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Sample records for substrate oxidation appetite

  1. Lean and obese dietary phenotypes: differences in energy and substrate metabolism and appetite.

    PubMed

    Clamp, Louise; Hehir, Anthony P J; Lambert, Estelle V; Beglinger, Christoph; Goedecke, Julia H

    2015-11-28

    This study aimed to characterise lean and obese phenotypes according to diet and body composition, and to compare fasting and postprandial appetite and metabolic profiles following a high-fat test meal. A total of ten lean (BMI40 and 30 kg/m2) high-fat consumers (OHF; >40 % energy from fat) were recruited. Before and following the test meal (4727 kJ (1130 kcal), 77 % fat, 20 % carbohydrate (CHO) and 3 % protein), fasting plasma glucose, insulin, leptin, ghrelin, peptide YY (PYY), RER, RMR and subjective appetite ratings (AR) were measured for 6 h. Thereafter, subjects consumed a self-selected portion of a standardised post-test meal (40 % fat, 45 % CHO and 15 % protein) and reported AR. Fasting (P=0·01) and postprandial (P<0·001) fat oxidation was significantly higher in LHF than in LLF but was not different between LHF and OHF. Although similar between the lean groups, fasting and postprandial energy expenditures were significantly higher in OHF compared with LHF (P<0·01). Despite similar AR across groups, LLF consumed a relatively greater quantity of the post-test meal than did LHF (7·87 (sd 2·96) v. 7·23 (sd 2·67) g/kg, P=0·013). The lean groups showed appropriate changes in plasma ghrelin and PYY following the test meal, whereas the OHF group showed a blunted response. In conclusion, the LHF phenotype had a greater capacity for fat oxidation, which may be protective against weight gain. OHF individuals had a blunted appetite hormone response to the high-fat test meal, which may subsequently increase energy intake, driving further weight gain. PMID:26382929

  2. Substrate-Sensitive Graphene Oxidation.

    PubMed

    Zhang, Zhuhua; Yin, Jun; Liu, Xiaofei; Li, Jidong; Zhang, Jiahuan; Guo, Wanlin

    2016-03-01

    The inertness of graphene toward reaction with ambient molecules is essential for realizing durable devices with stable performance. Many device applications require graphene to contact with substrates, but whose impact on the chemical property of graphene has been largely overlooked. Here, we combine comprehensive first-principles analyses with experiments to show that graphene oxidation is highly sensitive to substrates. Graphene remains inert on SiO2 and hexagonal boron nitride but becomes increasingly weak against oxidation on metal substrates because of enhanced charge transfer and chemical interaction between them. In particular, Ni and Co substrates lead to spontaneous oxidation of graphene, while a Cu substrate maximally promotes the oxygen diffusion on graphene, with an estimated diffusivity 13 orders of magnitude higher than that on freestanding graphene. Bilayer graphene is revealed to have high oxidation resistance independent of substrate and thus is a better choice for high-performance nanoelectronics. Our findings should be extendable to a wide spectrum of chemical functionalizations of two-dimensional materials mediated by substrates. PMID:26884318

  3. The SEEKING mind: primal neuro-affective substrates for appetitive incentive states and their pathological dynamics in addictions and depression.

    PubMed

    Alcaro, Antonio; Panksepp, Jaak

    2011-10-01

    Appetitive motivation and incentive states are essential functions sustained by a common emotional brain process, the SEEKING disposition, which drives explorative and approach behaviors, sustains goal-directed activity, promotes anticipatory cognitions, and evokes feelings of positive excitement which control reward-learning. All such functions are orchestrated by the same "archetypical" neural processes, activated in ancient subcortical areas and transported to the forebrain by the mesolimbic dopamine (ML-DA) system. In mammals, the neurophysiology of the SEEKING urge is expressed by DA-promoted high-frequency oscillations, in the form of transient and synchronized gamma waves (>30Hz) emerging in limbic forebrain and diffusing throughout basal ganglia-thalamocortical (BG-T-C) circuits. These patterns may be considered basic "SEEKING neurodynamic impulses" which represent the primary-process exploratory disposition getting integrated with information relative to the external and the internal environment. Abnormal manifestation of SEEKING and its neural substrates are evident in clinical depression and addiction. Specifically, depression is characterized by reduced recruitment of SEEKING, while addictions reflect re-organizations of the SEEKING disposition around ultra-specific appetitive memories and compulsive activities. PMID:21396397

  4. Involvement of oxidative stress in the regulation of NPY/CART-mediated appetite control in amphetamine-treated rats.

    PubMed

    Hsieh, Yih-Shou; Chen, Pei-Ni; Yu, Ching-Han; Chen, Chia-Hui; Tsai, Tsung-Ta; Kuo, Dong-Yih

    2015-05-01

    Amphetamine (AMPH) treatment can suppress appetite and increase oxidative stress in the brain. AMPH-induced appetite suppression is associated with the regulation of neuropeptide Y (NPY) and cocaine- and amphetamine-regulated transcript (CART) in the hypothalamus. The present study explored whether antioxidants, including glutathione S-transferase (GST) and glutathione peroxidase (GP), were involved in this NPY/CART-mediated appetite control. Rats were treated daily with AMPH for four days. Changes in food intake and expression levels of hypothalamic NPY, CART, GST, and GP were examined and compared. Results showed that, in AMPH-treated rats, (1) food intake and NPY expression decreased, while CART, GST, and GP expression increased; (2) NPY knockdown in the brain enhanced the decrease in NPY and the increases in CART, GST, and GP expression; and (3) central inhibition of reactive oxygen species production decreased GST and GP and modulated AMPH anorexia and the expression levels of NPY and CART. The present results suggest that oxidative stress in the brain participates in regulating NPY/CART-mediated appetite control in AMPH-treated rats. These results may advance the knowledge regarding the molecular mechanism of AMPH-evoked or NPY/CART-mediated appetite suppression. PMID:25825358

  5. High quality oxide films on substrates

    DOEpatents

    Ruckman, Mark W.; Strongin, Myron; Gao, Yong L.

    1994-01-01

    A method for providing an oxide film of a material on the surface of a substrate using a reactive deposition of the material onto the substrate surface in the presence of a solid or liquid layer of an oxidizing gas. The oxidizing gas is provided on the substrate surface in an amount sufficient to dissipate the latent heat of condensation occurring during deposition as well as creating a favorable oxidizing environment for the material.

  6. High quality oxide films on substrates

    DOEpatents

    Ruckman, M.W.; Strongin, M.; Gao, Y.L.

    1994-02-01

    A method is described for providing an oxide film of a material on the surface of a substrate using a reactive deposition of the material onto the substrate surface in the presence of a solid or liquid layer of an oxidizing gas. The oxidizing gas is provided on the substrate surface in an amount sufficient to dissipate the latent heat of condensation occurring during deposition as well as creating a favorable oxidizing environment for the material. 4 figures.

  7. Silica substrate or portion formed from oxidation of monocrystalline silicon

    DOEpatents

    Matzke, Carolyn M.; Rieger, Dennis J.; Ellis, Robert V.

    2003-07-15

    A method is disclosed for forming an inclusion-free silica substrate using a monocrystalline silicon substrate as the starting material and oxidizing the silicon substrate to convert it entirely to silica. The oxidation process is performed from both major surfaces of the silicon substrate using a conventional high-pressure oxidation system. The resulting product is an amorphous silica substrate which is expected to have superior etching characteristics for microfabrication than conventional fused silica substrates. The present invention can also be used to convert only a portion of a monocrystalline silicon substrate to silica by masking the silicon substrate and locally thinning a portion the silicon substrate prior to converting the silicon portion entirely to silica. In this case, the silica formed by oxidizing the thinned portion of the silicon substrate can be used, for example, as a window to provide optical access through the silicon substrate.

  8. Salt appetite in the elderly.

    PubMed

    Hendi, Khadeja; Leshem, Micah

    2014-11-28

    The present study investigated whether salt appetite in the elderly is impaired similar to thirst because of the commonality of their physiological substrates and whether alterations in salt appetite are related to mood. Elderly (65-85 years, n 30) and middle-aged (45-58 years, n 30) men and women were compared in two test sessions. Thirst, psychophysical ratings of taste solutions, dietary Na and energy intakes, seasoning with salt and sugar, number of salty and sweet snacks consumed, preferred amounts of salt in soup and sugar in tea, and an overall measure of salt appetite and its relationship with mood, nocturia and sleep were measured. Elderly participants were found to be less thirsty and respond less to thirst. In contrast, no impairment of salt appetite was found in them, and although they had a reduced dietary Na intake, it dissipated when corrected for their reduced dietary energy intake. Diet composition and Na intake were found to be similar in middle-aged and elderly participants, despite the lesser intake in elderly participants. There were no age-related differences in the intensity of taste or hedonic profile of Na, in salting habits, in tests of salting soup, or number of salty snacks consumed. No relationship of any measure of salt appetite with mood measured by the Positive and Negative Affect Schedule, frequency of nocturia, or sleep duration was observed. The age-related impairment of the physiology of mineralofluid regulation, while compromising thirst and fluid intake, spares salt appetite, suggesting that salt appetite in humans is not regulated physiologically. Intact salt appetite in the elderly might be utilised judiciously to prevent hyponatraemia, increase thirst and improve appetite. PMID:25287294

  9. Method for producing high quality oxide films on substrates

    DOEpatents

    Ruckman, M.W.; Strongin, M.; Gao, Y.L.

    1993-11-23

    A method is described for providing an oxide film of a material on the surface of a substrate using a reactive deposition of the material onto the substrate surface in the presence of a solid or liquid layer of an oxidizing gas. The oxidizing gas is provided on the substrate surface in an amount sufficient to dissipate the latent heat of condensation occurring during deposition as well as creating a favorable oxidizing environment for the material. 4 figures.

  10. Method for producing high quality oxide films on substrates

    DOEpatents

    Ruckman, Mark W.; Strongin, Myron; Gao, Yong L.

    1993-01-01

    A method for providing an oxide film of a material on the surface of a substrate using a reactive deposition of the material onto the substrate surface in the presence of a solid or liquid layer of an oxidizing gas. The oxidizing gas is provided on the substrate surface in an amount sufficient to dissipate the latent heat of condensation occurring during deposition as well as creating a favorable oxidizing environment for the material.

  11. Single crystal complex oxide on flexible substrate

    NASA Astrophysics Data System (ADS)

    Bakaul, Saidur; Serrao, Claudy; Lee, Oukjae; Salahuddin, Sayeef

    Flexible ferroelectrics are needed for various applications such as biocompatible energy harvesting and flexible memory. In this sector, most of the current research is focused on organic piezoelectric materials which have advantage of flexibility but suffers severely from poor energy conversion and generation efficiency. On the contrary, owing to very high electromechanical coupling factor (representing energy conversion efficiency) complex oxides are the best choices as energy harvesting and transduction elements, especially for transforming mechanical energies into electronic energy. Still their usage in energy harvesting is very limited mainly due to the stringent growth conditions of single crystals, high temperature needed for crystallization and lack of flexibility and stretchability. We have shown that single crystal Pb0.8Zr0.2TiO3 can be epitaxially transferred on flexible plastic substrate. The transferred PZT shows 70 uC/cm2 remnant polarization and dielectric constant over 100 even when it is bent. These results suggest the possibility of single crystal complex oxide devices on flexible platform.

  12. Oxidative-stress induced increase in circulating fatty acids does not contribute to phospholipase A2-dependent appetitive long-term memory failure in the pond snail Lymnaeastagnalis

    PubMed Central

    2014-01-01

    Background Reactive oxygen species (ROS) are essential for normal physiological functioning of the brain. However, uncompensated increase in ROS levels may results in oxidative stress. Phospholipase A2 (PLA2) is one of the key players activated by elevated ROS levels resulting in the hydrolysis of various products from the plasmamembrane such as peroxidized fatty acids. Free fatty acids (FFAs) and fatty acid metabolites are often implicated to the genesis of cognitive impairment. Previously we have shown that age-, and experimentally induced oxidative stress causes PLA2-dependent long-term memory (LTM) failure in an aversive operant conditioning model in Lymnaea stagnalis. In the present study, we investigate the effects of experimentally induced oxidative stress and the role of elevated levels of circulating FFAs on LTM function using a non-aversive appetitive classical conditioning paradigm. Results We show that intracoelomic injection of exogenous PLA2 or pro-oxidant induced PLA2 activation negatively affects LTM performance in our learning paradigm. In addition, we show that experimental induction of oxidative stress causes significant temporal changes in circulating FFA levels. Importantly, the time of training coincides with the peak of this change in lipid metabolism. However, intracoelomic injection with exogenous arachidonic acid, one of the main FFAs released by PLA2, does not affect LTM function. Moreover, sequestrating circulating FFAs with the aid of bovine serum albumin does not rescue pro-oxidant induced appetitive LTM failure. Conclusions Our data substantiates previous evidence linking lipid peroxidation and PLA2 activation to age- and oxidative stress-related cognitive impairment, neuronal dysfunction and disease. In addition however, our data indicate that lipid peroxidation induced increased levels of circulating (per)oxidized FFAs are not a factor in oxidative stress induced LTM impairment. PMID:24886155

  13. [Appetite and nutrition].

    PubMed

    Castillo, C; Acharán, X; Alvarez, P; Bustos, P

    1990-01-01

    Physiological, pathological and therapeutic aspect of appetite are reviewed. The importance of developmental alterations originated at early infancy and lack of appropriate interactions between mother and infant in abnormalities of appetite are emphasized. The role of vitamins, minerals and appetite stimulating drugs is analyzed and major disturbances of appetite and feeding conducts are described together with some therapeutic considerations on anorexia nervosa, bulimia, pica and rumination. PMID:2152223

  14. Alkoxysilane adsorption on metal oxide substrates

    NASA Technical Reports Server (NTRS)

    Ramsier, R. D.; Zhuang, G. R.; Henriksen, P. N.

    1989-01-01

    Reflection-absorption infrared and inelastic electron tunneling spectroscopies have been used to study adsorption of liquid phase mono-, di-, and trialkoxysilanes on evaporated Al and Cu substrates. Spectral evidence shows that substrate properties influence the chemical and physical nature of trialkoxysilane films and that silane functionality plays a role in molecular orientation. Results show that dialkoxysilane films contain structural gradients, with adsorption at the monomolecular level influenced by surface morphology, and with organofunctionality and dosing procedure affecting the formation of thicker films. Evidence is presented that monoalkoxysilanes react with alumina surfaces, and a broad, multipeaked band from 1600 to 1900/cm has been interpreted as characteristic of the silylated AlO(x)Pb interface.

  15. Interfacial Shear Strength of Oxide Scale and SS 441 Substrate

    SciTech Connect

    Liu, Wenning N.; Sun, Xin; Stephens, Elizabeth V.; Khaleel, Mohammad A.

    2011-05-01

    Recent developments on decreasing the operating temperature for Solid Oxide Fuel Cells (SOFCs) have enabled the use of high temperature ferritic alloys as interconnect materials. Oxide scale will inevitably grow on the ferritic interconnects in a high temperature oxidation environment of SOFCs. The growth of the oxide scale induces growth stresses in the scale layer and on the scale/substrate interface. These growth stresses combined with the thermal stresses induced upon stacking cooling by the thermal expansion coefficient mismatch between the oxide scale and the substrate may lead to scale delamination/buckling and eventual spallation, which may lead to serious cell performance degradation. Hence the interfacial adhesion strength between the oxide scale and the substrate is crucial to the reliability and durability of the metallic interconnect in SOFC operating environments. In this paper, we applied an integrated experimental/modeling methodology to quantify the interfacial adhesion strength between the oxide scale and the SS 441 metallic interconnect. The predicted interfacial strength is discussed in details.

  16. Effect of Substrate Thickness on Oxide Scale Spallation for Solid Oxide Fuel Cells

    SciTech Connect

    Liu, Wenning N.; Sun, Xin; Stephens, Elizabeth V.; Khaleel, Mohammad A.

    2011-07-01

    In this paper, the effect of the ferritic substrate's thickness on the delamination/spallation of the oxide scale was investigated experimentally and numerically. At the high-temperature oxidation environment of solid oxide fuel cells (SOFCs), a combination of growth stress with thermal stresses may lead to scale delamination/buckling and eventual spallation during SOFC stack cooling, even leading to serious degradation of cell performance. The growth stress is induced by the growth of the oxide scale on the scale/substrate interface, and thermal stress is induced by a mismatch of the coefficient of thermal expansion between the oxide scale and the substrate. The numerical results show that the interfacial shear stresses, which are the driving force of scale delamination between the oxide scale and the ferritic substrate, increase with the growth of the oxide scale and also with the thickness of the ferritic substrate; i.e., the thick ferritic substrate can easily lead to scale delamination and spallation. Experimental observation confirmed the predicted results of the delamination and spallation of the oxide scale on the ferritic substrate.

  17. Gold coated zinc oxide nanonecklaces as a SERS substrate.

    PubMed

    He, Lili; Shi, Jian; Sun, Xin; Lin, Mengshi; Yu, Ping; Li, Hao

    2011-04-01

    Faceted zinc oxide nanonecklace (ZnO NN) arrays were grown on r-plane sapphires along one direction (ZnO [0001] II sapphire [10-11] and ZnO (-12-10) II sapphire (01-12)) using chemical vapor deposition. After coated with 45 nm gold films and annealed at 250 degrees C for 30 seconds, the coated ZnO NNs exhibit satisfactory and stable surface enhanced Raman scattering (SERS) effects when tested with melamine and other chemicals. The limit of detection of melamine is 10(-5) mol/L and the analytical enhancement factor is 10(4), which is competitive to a commercial substrate. This study indicates that gold coated ZnO NN substrates have a great potential as SERS-active substrates in rapid detection of trace amount food contaminants such as melamine and other chemicals. PMID:21776731

  18. Epitaxial Zinc Oxide Semiconductor Film deposited on Gallium Nitride Substrate

    NASA Astrophysics Data System (ADS)

    McMaster, Michael; Oder, Tom

    2011-04-01

    Zinc oxide (ZnO) is a wide bandgap semiconductor which is very promising for making efficient electronic and optical devices. The goal of this research was to produce high quality ZnO film on gallium nitride (GaN) substrate by optimizing the substrate temperature. The GaN substrates were chemically cleaned and mounted on a ceramic heater and loaded into a vacuum deposition chamber that was pumped down to a base pressure of 3 x 10-7 Torr. The film deposition was preceded by a 30 minute thermal desorption carried in vacuum at 500 ^oC. The ZnO thin film was then sputter-deposited using an O2/Ar gas mixture onto GaN substrates heated at temperatures varying from 20 ^oC to 500 ^oC. Post-deposition annealing was done in a rapid thermal processor at 900 ^oC for 5 min in an ultrapure N2 ambient to improve the crystal quality of the films. The films were then optically characterized using photoluminescence (PL) measurement with a UV laser excitation. Our measurements reveal that ZnO films deposited on GaN substrate held at 200 ^oC gave the best film with the highest luminous intensity, with a peak energy of 3.28 eV and a full width half maximum of 87.4 nm. Results from low temperature (10 K) PL measurements and from x-ray diffraction will also be presented.

  19. Substrate Oxidation by Indoleamine 2,3-Dioxygenase

    PubMed Central

    Booth, Elizabeth S.; Basran, Jaswir; Lee, Michael; Handa, Sandeep; Raven, Emma L.

    2015-01-01

    The kynurenine pathway is the major route of l-tryptophan (l-Trp) catabolism in biology, leading ultimately to the formation of NAD+. The initial and rate-limiting step of the kynurenine pathway involves oxidation of l-Trp to N-formylkynurenine. This is an O2-dependent process and catalyzed by indoleamine 2,3-dioxygenase and tryptophan 2,3-dioxygenase. More than 60 years after these dioxygenase enzymes were first isolated (Kotake, Y., and Masayama, I. (1936) Z. Physiol. Chem. 243, 237–244), the mechanism of the reaction is not established. We examined the mechanism of substrate oxidation for a series of substituted tryptophan analogues by indoleamine 2,3-dioxygenase. We observed formation of a transient intermediate, assigned as a Compound II (ferryl) species, during oxidation of l-Trp, 1-methyl-l-Trp, and a number of other substrate analogues. The data are consistent with a common reaction mechanism for indoleamine 2,3-dioxygenase-catalyzed oxidation of tryptophan and other tryptophan analogues. PMID:26511316

  20. Electrical and mechanical properties of graphene oxide on flexible substrate

    NASA Astrophysics Data System (ADS)

    Kang, Shao-Hui; Fang, Te-Hua; Hong, Zheng-Han

    2013-12-01

    Graphene oxide (GO) was deposited via the electrophoretic deposition (EPD) method to lower the oxygen concentration of graphene sheets for large-scale production. In addition, the direct synthesis of large-scale GO films using transfer processes on a polydimethylsiloxane (PDMS) substrate was conducted. The thickness of the GO films was controlled to adjust the optical, electrical, and mechanical properties. The Young's modulus values of films with thicknesses of 100-200 nm were 324-529 GPa. Moreover, the GO films exhibited excellent conductivity, with a sheet resistance of 276-2024 Ω/sq at 23-77% transparency. Experiments show that transfer processes for flexible substrates can produce high-quality cost-effective transparent conductive films.

  1. Oxidized SWCNT chemically attached to a modified copper substrate

    NASA Astrophysics Data System (ADS)

    Hernandez, Dionne; Cabrera, Carlos R.; Mendez, Laura; Diaz-Serrano, Madeline; Vega, Omar; Weiner, Brad R.; Rosa, Luis G.

    2015-08-01

    Oxidized single-wall carbon nanotubes were chemically attached to a modified copper substrate by means of a 4-aminothiophenol (4-ATP) self-assembly monolayer (SAM). This bottom up approach offers a low cost route to attach carbon nanotubes by using a condensation reaction. Here, the exposed amine from the 4-ATP SAM reacts with the carboxylic group (COOH) on the CNT. The reaction was followed using ATR-FTIR and the surface was characterized using SEM, XPS, and Raman. The analytical techniques used on this study suggest that the condensation reaction employed using a carbodiimide such as 1-Ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride (EDC) produced SWCNT attached to the copper substrate.

  2. Two Oxidation Sites for Low Redox Potential Substrates

    PubMed Central

    Morales, María; Mate, María J.; Romero, Antonio; Martínez, María Jesús; Martínez, Ángel T.; Ruiz-Dueñas, Francisco J.

    2012-01-01

    Versatile peroxidase shares with manganese peroxidase and lignin peroxidase the ability to oxidize Mn2+ and high redox potential aromatic compounds, respectively. Moreover, it is also able to oxidize phenols (and low redox potential dyes) at two catalytic sites, as shown by biphasic kinetics. A high efficiency site (with 2,6-dimethoxyphenol and p-hydroquinone catalytic efficiencies of ∼70 and ∼700 s−1 mm−1, respectively) was localized at the same exposed Trp-164 responsible for high redox potential substrate oxidation (as shown by activity loss in the W164S variant). The second site, characterized by low catalytic efficiency (∼3 and ∼50 s−1 mm−1 for 2,6-dimethoxyphenol and p-hydroquinone, respectively) was localized at the main heme access channel. Steady-state and transient-state kinetics for oxidation of phenols and dyes at the latter site were improved when side chains of residues forming the heme channel edge were removed in single and multiple variants. Among them, the E140G/K176G, E140G/P141G/K176G, and E140G/W164S/K176G variants attained catalytic efficiencies for oxidation of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) at the heme channel similar to those of the exposed tryptophan site. The heme channel enlargement shown by x-ray diffraction of the E140G, P141G, K176G, and E140G/K176G variants would allow a better substrate accommodation near the heme, as revealed by the up to 26-fold lower Km values (compared with native VP). The resulting interactions were shown by the x-ray structure of the E140G-guaiacol complex, which includes two H-bonds of the substrate with Arg-43 and Pro-139 in the distal heme pocket (at the end of the heme channel) and several hydrophobic interactions with other residues and the heme cofactor. PMID:23071108

  3. Flexible Metal Oxide/Graphene Oxide Hybrid Neuromorphic Transistors on Flexible Conducting Graphene Substrates.

    PubMed

    Wan, Chang Jin; Liu, Yang Hui; Feng, Ping; Wang, Wei; Zhu, Li Qiang; Liu, Zhao Ping; Shi, Yi; Wan, Qing

    2016-07-01

    Flexible metal oxide/graphene oxide hybrid multi-gate neuromorphic transistors are fabricated on flexible conducting graphene substrates. Dendritic integrations in both spatial and temporal modes are emulated, and spatiotemporal correlated logics are obtained. A proof-of-principle visual system model for emulating Lobula Giant Motion Detector neuron is also investigated. The results are of great significance for flexible sensors and neuromorphic cognitive systems. PMID:27159546

  4. Charge inhomogeneity determines oxidative reactivity of graphene on substrates.

    PubMed

    Yamamoto, Mahito; Einstein, Theodore L; Fuhrer, Michael S; Cullen, William G

    2012-09-25

    Single-layer graphene (SLG) supported on SiO(2) shows anomalously large chemical reactivity compared to thicker graphene, with charge inhomogeneity-induced potential fluctuations or topographic corrugations proposed as the cause. Here we systematically probe the oxidative reactivity of graphene supported on substrates with different surface roughnesses and charged impurity densities: hexagonal boron nitride (hBN), mica, thermally grown SiO(2) on Si, and SiO(2) nanoparticle thin films. SLG on low charge trap density hBN is not etched and shows little doping after oxygen treatment at temperatures up to 550 °C, in sharp contrast with oxidative etching under similar conditions of graphene on high charge trap density SiO(2) and mica. Furthermore, bilayer graphene shows reduced reactivity compared to SLG regardless of its substrate-induced roughness. Together the observations indicate that graphene's reactivity is predominantly controlled by charge inhomogeneity-induced potential fluctuations rather than surface roughness. PMID:22917254

  5. Atomic layer deposition of hafnium oxide on germanium substrates

    NASA Astrophysics Data System (ADS)

    Delabie, Annelies; Puurunen, Riikka L.; Brijs, Bert; Caymax, Matty; Conard, Thierry; Onsia, Bart; Richard, Olivier; Vandervorst, Wilfried; Zhao, Chao; Heyns, Marc M.; Meuris, Marc; Viitanen, Minna M.; Brongersma, Hidde H.; de Ridder, Marco; Goncharova, Lyudmila V.; Garfunkel, Eric; Gustafsson, Torgny; Tsai, Wilman

    2005-03-01

    Germanium combined with high-κ dielectrics has recently been put forth by the semiconductor industry as potential replacement for planar silicon transistors, which are unlikely to accommodate the severe scaling requirements for sub-45-nm generations. Therefore, we have studied the atomic layer deposition (ALD) of HfO2 high-κ dielectric layers on HF-cleaned Ge substrates. In this contribution, we describe the HfO2 growth characteristics, HfO2 bulk properties, and Ge interface. Substrate-enhanced HfO2 growth occurs: the growth per cycle is larger in the first reaction cycles than the steady growth per cycle of 0.04nm. The enhanced growth goes together with island growth, indicating that more than a monolayer coverage of HfO2 is required for a closed film. A closed HfO2 layer is achieved after depositing 4-5HfO2 monolayers, corresponding to about 25 ALD reaction cycles. Cross-sectional transmission electron microscopy images show that HfO2 layers thinner than 3nm are amorphous as deposited, while local epitaxial crystallization has occurred in thicker HfO2 films. Other HfO2 bulk properties are similar for Ge and Si substrates. According to this physical characterization study, HfO2 can be used in Ge-based devices as a gate oxide with physical thickness scaled down to 1.6nm.

  6. Oxide perovskite crystals for HTSC film substrates microwave applications

    NASA Technical Reports Server (NTRS)

    Bhalla, A. S.; Guo, Ruyan

    1995-01-01

    The research focused upon generating new substrate materials for the deposition of superconducting yttrium barium cuprate (YBCO) has yielded several new hosts in complex perovskites, modified perovskites, and other structure families. New substrate candidates such as Sr(Al(1/2)Ta(1/2))O3 and Sr(Al(1/2)Nb(1/2))O3, Ba(Mg(1/3)Ta(2/3))O3 in complex oxide perovskite structure family and their solid solutions with ternary perovskite LaAlO3 and NdGaO3 are reported. Conventional ceramic processing techniques were used to fabricate dense ceramic samples. A laser heated molten zone growth system was utilized for the test-growth of these candidate materials in single crystal fiber form to determine crystallographic structure, melting point, thermal, and dielectric properties as well as to make positive identification of twin free systems. Some of those candidate materials present an excellent combination of properties suitable for microwave HTSC substrate applications.

  7. Oxidation stress evolution and relaxation of oxide film/metal substrate system

    NASA Astrophysics Data System (ADS)

    Dong, Xuelin; Feng, Xue; Hwang, Keh-Chih

    2012-07-01

    Stresses in the oxide film/metal substrate system are crucial to the reliability of the system at high temperature. Two models for predicting the stress evolution during isothermal oxidation are proposed. The deformation of the system is depicted by the curvature for single surface oxidation. The creep strain of the oxide and metal, and the lateral growth strain of the oxide are considered. The proposed models are compared with the experimental results in literature, which demonstrates that the elastic model only considering for elastic strain gives an overestimated stress in magnitude, but the creep model is consistent with the experimental data and captures the stress relaxation phenomenon during oxidation. The effects of the parameter for the lateral growth strain rate are also analyzed.

  8. Lateral solid-phase epitaxy of oxide thin films on glass substrate seeded with oxide nanosheets.

    PubMed

    Taira, Kenji; Hirose, Yasushi; Nakao, Shoichiro; Yamada, Naoomi; Kogure, Toshihiro; Shibata, Tatsuo; Sasaki, Takayoshi; Hasegawa, Tetsuya

    2014-06-24

    We developed a technique to fabricate oxide thin films with uniaxially controlled crystallographic orientation and lateral size of more than micrometers on amorphous substrates. This technique is lateral solid-phase epitaxy, where epitaxial crystallization of amorphous precursor is seeded with ultrathin oxide nanosheets sparsely (≈10% coverage) deposited on the substrate. Transparent conducting Nb-doped anatase TiO2 thin films were fabricated on glass substrates by this technique. Perfect (001) orientation and large grains with lateral sizes up to 10 μm were confirmed by X-ray diffraction, atomic force microscopy, and electron beam backscattering diffraction measurements. As a consequence of these features, the obtained film exhibited excellent electrical transport properties comparable to those of epitaxial thin films on single-crystalline substrates. This technique is a versatile method for fabricating high-quality oxide thin films other than anatase TiO2 and would increase the possible applications of oxide-based thin film devices. PMID:24867286

  9. Polycrystalline ferroelectric or multiferroic oxide articles on biaxially textured substrates and methods for making same

    SciTech Connect

    Goyal, Amit; Shin, Junsoo

    2015-03-31

    A polycrystalline ferroelectric and/or multiferroic oxide article includes a substrate having a biaxially textured surface; at least one biaxially textured buffer layer supported by the substrate; and a biaxially textured ferroelectric or multiferroic oxide layer supported by the buffer layer. Methods for making polycrystalline ferroelectric and/or multiferroic oxide articles are also disclosed.

  10. Decoding the Substrate Supply to Human Neuronal Nitric Oxide Synthase

    PubMed Central

    Habermeier, Alice; Closs, Ellen I.

    2013-01-01

    Nitric oxide, produced by the neuronal nitric oxide synthase (nNOS) from L-arginine is an important second messenger molecule in the central nervous system: It influences the synthesis and release of neurotransmitters and plays an important role in long-term potentiation, long-term depression and neuroendocrine secretion. However, under certain pathological conditions such as Alzheimer’s or Parkinson’s disease, stroke and multiple sclerosis, excessive NO production can lead to tissue damage. It is thus desirable to control NO production in these situations. So far, little is known about the substrate supply to human nNOS as a determinant of its activity. Measuring bioactive NO via cGMP formation in reporter cells, we demonstrate here that nNOS in both, human A673 neuroepithelioma and TGW-nu-I neuroblastoma cells can be fast and efficiently nourished by extracellular arginine that enters the cells via membrane transporters (pool I that is freely exchangeable with the extracellular space). When this pool was depleted, NO synthesis was partially sustained by intracellular arginine sources not freely exchangeable with the extracellular space (pool II). Protein breakdown made up by far the largest part of pool II in both cell types. In contrast, citrulline to arginine conversion maintained NO synthesis only in TGW-nu-I neuroblastoma, but not A673 neuroepithelioma cells. Histidine mimicked the effect of protease inhibitors causing an almost complete nNOS inhibition in cells incubated additionally in lysine that depletes the exchangeable arginine pool. Our results identify new ways to modulate nNOS activity by modifying its substrate supply. PMID:23874440

  11. Efficient Direct Reduction of Graphene Oxide by Silicon Substrate

    PubMed Central

    Chan Lee, Su; Some, Surajit; Wook Kim, Sung; Jun Kim, Sun; Seo, Jungmok; Lee, Jooho; Lee, Taeyoon; Ahn, Jong-Hyun; Choi, Heon-Jin; Chan Jun, Seong

    2015-01-01

    Graphene has been studied for various applications due to its excellent properties. Graphene film fabrication from solutions of graphene oxide (GO) have attracted considerable attention because these procedures are suitable for mass production. GO, however, is an insulator, and therefore a reduction process is required to make the GO film conductive. These reduction procedures require chemical reducing agents or high temperature annealing. Herein, we report a novel direct and simple reduction procedure of GO by silicon, which is the most widely used material in the electronics industry. In this study, we also used silicon nanosheets (SiNSs) as reducing agents for GO. The reducing effect of silicon was confirmed by various characterization methods. Furthermore, the silicon wafer was also used as a reducing template to create a reduced GO (rGO) film on a silicon substrate. By this process, a pure rGO film can be formed without the impurities that normally come from chemical reducing agents. This is an easy and environmentally friendly method to prepare large scale graphene films on Si substrates. PMID:26194107

  12. Efficient Direct Reduction of Graphene Oxide by Silicon Substrate.

    PubMed

    Lee, Su Chan; Some, Surajit; Kim, Sung Wook; Kim, Sun Jun; Seo, Jungmok; Lee, Jooho; Lee, Taeyoon; Ahn, Jong-Hyun; Choi, Heon-Jin; Jun, Seong Chan

    2015-01-01

    Graphene has been studied for various applications due to its excellent properties. Graphene film fabrication from solutions of graphene oxide (GO) have attracted considerable attention because these procedures are suitable for mass production. GO, however, is an insulator, and therefore a reduction process is required to make the GO film conductive. These reduction procedures require chemical reducing agents or high temperature annealing. Herein, we report a novel direct and simple reduction procedure of GO by silicon, which is the most widely used material in the electronics industry. In this study, we also used silicon nanosheets (SiNSs) as reducing agents for GO. The reducing effect of silicon was confirmed by various characterization methods. Furthermore, the silicon wafer was also used as a reducing template to create a reduced GO (rGO) film on a silicon substrate. By this process, a pure rGO film can be formed without the impurities that normally come from chemical reducing agents. This is an easy and environmentally friendly method to prepare large scale graphene films on Si substrates. PMID:26194107

  13. Regulation of Blood Pressure, Appetite, and Glucose by Leptin After Inactivation of Insulin Receptor Substrate 2 Signaling in the Entire Brain or in Proopiomelanocortin Neurons.

    PubMed

    do Carmo, Jussara M; da Silva, Alexandre A; Wang, Zhen; Freeman, Nathan J; Alsheik, Ammar J; Adi, Ahmad; Hall, John E

    2016-02-01

    Insulin receptor substrate 2 (IRS2) is one of the 3 major leptin receptor signaling pathways, but its role in mediating the chronic effects of leptin on blood pressure, food intake, and glucose regulation is unclear. We tested whether genetic inactivation of IRS2 in the entire brain (IRS2/Nestin-cre mice) or specifically in proopiomelanocortin (POMC) neurons (IRS2/POMC-cre mice) attenuates the chronic cardiovascular, metabolic, and antidiabetic effects of leptin. Mice were instrumented with telemetry probes for measurement of blood pressure and heart rate and with venous catheters for intravenous infusions. After a 5-day control period, mice received leptin infusion (2 μg/kg per minute) for 7 days. Compared with control IRS2(flox/flox) mice, IRS2/POMC-cre mice had similar body weight and food intake (33±1 versus 35±1 g and 3.6±0.5 versus 3.8±0.2 g per day) but higher mean arterial pressure (MAP) and heart rate (110±2 versus 102±2 mm Hg and 641±9 versus 616±5 bpm). IRS2/Nestin-cre mice were heavier (38±2 g), slightly hyperphagic (4.5±1.0 g per day), and had higher MAP and heart rate (108±2 mm Hg and 659±9 bpm) compared with control mice. Leptin infusion gradually increased MAP despite decreasing food intake by 31% in IRS2(flox/flox) and in Nestin-cre control mice. In contrast, leptin infusion did not change MAP in IRS2/Nestin-cre or IRS2/POMC-cre mice. The anorexic and antidiabetic effects of leptin, however, were similar in all 3 groups. These results indicate that IRS2 signaling in the central nervous system, and particularly in POMC neurons, is essential for the chronic actions of leptin to raise MAP but not for its anorexic or antidiabetic effects. PMID:26628674

  14. Titanium oxide as substrate for neural cell growth.

    PubMed

    Carballo-Vila, Mónica; Moreno-Burriel, Berta; Chinarro, Eva; Jurado, José R; Casañ-Pastor, Nieves; Collazos-Castro, Jorge E

    2009-07-01

    Titanium oxide has antiinflammatory activity and tunable electrochemical behavior that make it an attractive material for the fabrication of implantable devices. The most stable composition is TiO2 and occurs mainly in three polymorphs, namely, anatase, rutile, and brookite, which differ in its crystallochemical properties. Here, we report the preparation of rutile surfaces that permit good adherence and axonal growth of cultured rat cerebral cortex neurons. Rutile disks were obtained by sinterization of TiO2 powders of commercial origin or precipitated from hydrolysis of Ti(IV)-isopropoxide. Commercial powders sintered at 1300-1600 degrees C produced rutile surfaces with abnormal grain growth, probably because of impurities of the powders. Neurons cultured on those surfaces survived in variable numbers and showed fewer neurites than on control materials. On the other hand, rutile sintered from precipitated powders had less contaminants and more homogenous grain growth. By adjusting the thermal treatment it was possible to obtain surfaces performing well as substrate for neuron survival for at least 10 days. Some surfaces permitted normal axonal elongation, whereas dendrite growth was generally impaired. These findings support the potential use of titanium oxide in neuroprostheses and other devices demanding materials with enhanced properties in terms of biocompatibility and axon growth promotion. PMID:18481786

  15. Energy intake over 2 days is unaffected by acute sprint interval exercise despite increased appetite and energy expenditure.

    PubMed

    Beaulieu, Kristine; Olver, T Dylan; Abbott, Kolten C; Lemon, Peter W R

    2015-01-01

    A cumulative effect of reduced energy intake, increased oxygen consumption, and/or increased lipid oxidation could explain the fat loss associated with sprint interval exercise training (SIT). This study assessed the effects of acute sprint interval exercise (SIE) on energy intake, subjective appetite, appetite-related peptides, oxygen consumption, and respiratory exchange ratio over 2 days. Eight men (25 ± 3 years, 79.6 ± 9.7 kg, body fat 13% ± 6%; mean ± SD) completed 2 experimental treatments: SIE and recovery (SIEx) and nonexercise control. Each 34-h treatment consisted of 2 consecutive 10-h test days. Between 0800-1800 h, participants remained in the laboratory for 8 breath-by-breath gas collections, 3 buffet-type meals, 14 appetite ratings, and 4 blood samples for appetite-related peptides. Treatment comparisons were made using 2-way repeated measures ANOVA or t tests. An immediate, albeit short-lived (<1 h), postexercise suppression of appetite and increase in peptide YY (PYY) were observed (P < 0.001). However, overall hunger and motivation to eat were greater during SIEx (P < 0.02) without affecting energy intake. Total 34-h oxygen consumption was greater during SIEx (P = 0.04), elicited by the 1491-kJ (22%) greater energy expenditure over the first 24 h (P = 0.01). Despite its effects on oxygen consumption, appetite, and PYY, acute SIE did not affect energy intake. Consequently, if these dietary responses to SIE are sustained with regular SIT, augmentations in oxygen consumption and/or a substrate shift toward increased fat use postexercise are most likely responsible for the observed body fat loss with this type of exercise training. PMID:25494974

  16. Gastrointestinal hormones regulating appetite.

    PubMed

    Chaudhri, Owais; Small, Caroline; Bloom, Steve

    2006-07-29

    The role of gastrointestinal hormones in the regulation of appetite is reviewed. The gastrointestinal tract is the largest endocrine organ in the body. Gut hormones function to optimize the process of digestion and absorption of nutrients by the gut. In this capacity, their local effects on gastrointestinal motility and secretion have been well characterized. By altering the rate at which nutrients are delivered to compartments of the alimentary canal, the control of food intake arguably constitutes another point at which intervention may promote efficient digestion and nutrient uptake. In recent decades, gut hormones have come to occupy a central place in the complex neuroendocrine interactions that underlie the regulation of energy balance. Many gut peptides have been shown to influence energy intake. The most well studied in this regard are cholecystokinin (CCK), pancreatic polypeptide, peptide YY, glucagon-like peptide-1 (GLP-1), oxyntomodulin and ghrelin. With the exception of ghrelin, these hormones act to increase satiety and decrease food intake. The mechanisms by which gut hormones modify feeding are the subject of ongoing investigation. Local effects such as the inhibition of gastric emptying might contribute to the decrease in energy intake. Activation of mechanoreceptors as a result of gastric distension may inhibit further food intake via neural reflex arcs. Circulating gut hormones have also been shown to act directly on neurons in hypothalamic and brainstem centres of appetite control. The median eminence and area postrema are characterized by a deficiency of the blood-brain barrier. Some investigators argue that this renders neighbouring structures, such as the arcuate nucleus of the hypothalamus and the nucleus of the tractus solitarius in the brainstem, susceptible to influence by circulating factors. Extensive reciprocal connections exist between these areas and the hypothalamic paraventricular nucleus and other energy-regulating centres of the

  17. Postprandial thermogenesis and substrate oxidation are unaffected by sleep restriction

    PubMed Central

    Shechter, Ari; Rising, Russell; Wolfe, Scott; Albu, Jeanine B.; St-Onge, Marie-Pierre

    2014-01-01

    Background/Objectives The extent to which alterations in energy expenditure (EE) in response to sleep restriction contribute to the short sleep-obesity relationship is not clearly defined. Short sleep may induce changes in resting metabolic rate (RMR), thermic effect of food (TEF), and postprandial substrate oxidation. Subjects/Methods Ten females (age and BMI: 22-43 y and 23.4-28 kg/m2) completed a randomized, crossover study assessing the effects of short (4 h/night) and habitual (8 h/night) sleep duration on fasting and postprandial RMR and respiratory quotient (RQ). Measurements were taken after 3 nights using whole-room indirect calorimetry. The TEF was assessed over a 6-h period following consumption of a high-fat liquid meal. Results Short vs. habitual sleep did not affect RMR (1.01 ± 0.05 and 0.97 ± 0.04 kcal/min; p=0.23). Fasting RQ was significantly lower after short vs. habitual sleep (0.84 ± 0.01 and 0.88 ± 0.01; p=0.028). Postprandial EE (short: 1.13 ± 0.04 and habitual: 1.10 ± 0.04, p=0.09) and RQ (short: 0.88 ± 0.01 and habitual: 0.88 ± 0.01, p=0.50) after the high-fat meal were not different between conditions. TEF was similar between conditions (0.24 ± 0.02 kcal/min in both; p=0.98), as was the ~6-h incremental area under the curve (1.16 ± 0.10 and 1.17 ± 0.09 kcal/min x 356 min after short and habitual sleep, respectively; p=0.92). Conclusions Current findings observed in non-obese healthy premenopausal women do not support the hypothesis that alterations in TEF and postprandial substrate oxidation are major contributors to the higher rate of obesity observed in short sleepers. In exploring a role of sleep duration on EE, research should focus on potential alterations in physical activity to explain the increased obesity risk in short sleepers. PMID:24352294

  18. Composite anodes based on nanotube titanium oxide from electro-oxidation of Ti metal substrate

    NASA Astrophysics Data System (ADS)

    Pozio, A.; Carewska, M.; Mura, F.; D'Amato, R.; Falconieri, M.; De Francesco, M.; Appetecchi, G. B.

    2014-02-01

    In this manuscript is reported an investigation on lithium-ion battery composite anodes based on nanotube titanium oxide active material obtained from electrochemical oxidation of titanium metal substrates. Nanotube TiO2 showed a good nominal capacity, particularly taking into account that no electronic conductive additive as well as no binder was incorporated into the TiO2 material. The performance of nanotube titanium oxide anode tapes was compared with that of electrodes based on TiO2 both commercially available and obtained from laser pyrolysis. Cycling tests have indicated that the anodes based on electrosynthesized nanotube TiO2 exhibit the best performance in terms of capacity values and rate capability in combination with very good capacity retention and coulombic efficiency leveling 100% even at high rates.

  19. Enhanced transparent conducting networks on plastic substrates modified with highly oxidized graphene oxide nanosheets

    NASA Astrophysics Data System (ADS)

    Woo, Jong Seok; Sin, Dong Hun; Kim, Haena; Jang, Jeong In; Kim, Ho Young; Lee, Geon-Woong; Cho, Kilwon; Park, Soo-Young; Han, Joong Tark

    2016-03-01

    Atomically thin and two-dimensional graphene oxide (GO) is a very fascinating material because of its functional groups, high transparency, and solution processability. Here we show that highly oxidized GO (HOGO) nanosheets serve as an effective interfacial modifier of transparent conducting films with one-dimensional (1D) silver nanowires (AgNWs) and single-walled carbon nanotubes (SWCNTs). Optically transparent and small-sized GO nanosheets, with minimal sp2 domains, were successfully fabricated by step-wise oxidation and exfoliation of graphite. We demonstrated that under-coated HOGO further decreases the sheet resistance of the SWCNT film top-coated with HOGO by increasing the contact area between the SWCNTs and HOGO nanosheets by generating hole carriers in the SWCNT as a result of charge transfer. Moreover, HOGO nanosheets with AgNWs contribute to the efficient thermal joining of AgNW networks on plastic substrates by limiting the thermal embedding of AgNWs into the plastic surface, resulting in efficient decrease of the sheet resistance. Furthermore, flexible organic photovoltaic cells with GO-modified AgNW anodes on a flexible substrate were successfully demonstrated.Atomically thin and two-dimensional graphene oxide (GO) is a very fascinating material because of its functional groups, high transparency, and solution processability. Here we show that highly oxidized GO (HOGO) nanosheets serve as an effective interfacial modifier of transparent conducting films with one-dimensional (1D) silver nanowires (AgNWs) and single-walled carbon nanotubes (SWCNTs). Optically transparent and small-sized GO nanosheets, with minimal sp2 domains, were successfully fabricated by step-wise oxidation and exfoliation of graphite. We demonstrated that under-coated HOGO further decreases the sheet resistance of the SWCNT film top-coated with HOGO by increasing the contact area between the SWCNTs and HOGO nanosheets by generating hole carriers in the SWCNT as a result of charge

  20. Neuropharmacology of Human Appetite Expression

    ERIC Educational Resources Information Center

    Halford, Jason C. G.; Harrold, Joanne A.

    2008-01-01

    The regulation of appetite relies on the integration of numerous episodic (meal) and tonic (energy storage) generated signals in energy regulatory centres within the central nervous system (CNS). These centers provide the pharmacological potential to modify human appetite (hunger and satiety) to increase or decrease caloric intake, or to normalize…

  1. Enhanced transparent conducting networks on plastic substrates modified with highly oxidized graphene oxide nanosheets.

    PubMed

    Woo, Jong Seok; Sin, Dong Hun; Kim, Haena; Jang, Jeong In; Kim, Ho Young; Lee, Geon-Woong; Cho, Kilwon; Park, Soo-Young; Han, Joong Tark

    2016-03-28

    Atomically thin and two-dimensional graphene oxide (GO) is a very fascinating material because of its functional groups, high transparency, and solution processability. Here we show that highly oxidized GO (HOGO) nanosheets serve as an effective interfacial modifier of transparent conducting films with one-dimensional (1D) silver nanowires (AgNWs) and single-walled carbon nanotubes (SWCNTs). Optically transparent and small-sized GO nanosheets, with minimal sp(2) domains, were successfully fabricated by step-wise oxidation and exfoliation of graphite. We demonstrated that under-coated HOGO further decreases the sheet resistance of the SWCNT film top-coated with HOGO by increasing the contact area between the SWCNTs and HOGO nanosheets by generating hole carriers in the SWCNT as a result of charge transfer. Moreover, HOGO nanosheets with AgNWs contribute to the efficient thermal joining of AgNW networks on plastic substrates by limiting the thermal embedding of AgNWs into the plastic surface, resulting in efficient decrease of the sheet resistance. Furthermore, flexible organic photovoltaic cells with GO-modified AgNW anodes on a flexible substrate were successfully demonstrated. PMID:26946993

  2. Stress generation in thermally grown oxide films. [oxide scale spalling from superalloy substrates

    NASA Technical Reports Server (NTRS)

    Kumnick, A. J.; Ebert, L. J.

    1981-01-01

    A three dimensional finite element analysis was conducted, using the ANSYS computer program, of the stress state in a thin oxide film thermally formed on a rectangular piece of NiCrAl alloy. The analytical results indicate a very high compressive stress in the lateral directions of the film (approximately 6200 MPa), and tensile stresses in the metal substrate that ranged from essentially zero to about 55 MPa. It was found further that the intensity of the analytically determined average stresses could be approximated reasonably well by the modification of an equation developed previously by Oxx for stresses induced into bodies by thermal gradients.

  3. Effect of substrate temperature on structural and electrical properties of RF sputtered hafnium oxide thin films

    SciTech Connect

    Das, K. C.; Ghosh, S. P.; Tripathy, N.; Kar, J. P.; Bose, G.; Lee, T.; Myoung, J. M.

    2015-06-24

    In this work hafnium oxide thin films were deposited on p-type silicon substrate by Radio frequency magnetron sputtering at different substrate temperature ranging from room temperature to 300 °C. The structural and electrical properties of the sputtered films were investigated by x-ray diffraction, capacitance-voltage and current-voltage measurements. The XRD results show the formation monoclinic structure of the hafnium oxide thin films. The shifting of C-V curves towards negative voltage side depicts the increase in positive oxide charges with the rise of substrate temperature. Leakage current was found increased, when temperature enhanced from room temperature to 300 °C.

  4. Novel synthetic methodology for controlling the orientation of zinc oxide nanowires grown on silicon oxide substrates.

    PubMed

    Cho, Jinhyun; Salleh, Najah; Blanco, Carlos; Yang, Sungwoo; Lee, Chul-Jin; Kim, Young-Woo; Kim, Jungsang; Liu, Jie

    2014-04-01

    This study presents a simple method to reproducibly obtain well-aligned vertical ZnO nanowire arrays on silicon oxide (SiOx) substrates using seed crystals made from a mixture of ammonium hydroxide (NH4OH) and zinc acetate (Zn(O2CCH3)2) solution. In comparison, high levels of OH(-) concentration obtained using NaOH or KOH solutions lead to incorporation of Na or K atoms into the seed crystals, destroying the c-axis alignment of the seeds and resulting in the growth of misaligned nanowires. The use of NH4OH eliminates the metallic impurities and ensures aligned nanowire growth in a wide range of OH(-) concentrations in the seed solution. The difference of crystalline orientations between NH4OH- and NaOH-based seeds is directly observed by lattice-resolved images and electron diffraction patterns using a transmission electron microscope (TEM). This study obviously suggests that metallic impurities incorporated into the ZnO nanocrystal seeds are one of the factors that generates the misaligned ZnO nanowires. This method also enables the use of silicon oxide substrates for the growth of vertically aligned nanowires, making ZnO nanostructures compatible with widely used silicon fabrication technology. PMID:24584438

  5. A Molecular Dissociation between Cued and Contextual Appetitive Learning

    ERIC Educational Resources Information Center

    Kheirbek, Mazen A.; Beeler, Jeff A.; Chi, Wanhao; Ishikawa, Yoshihiro; Zhuang, Xiaoxi

    2010-01-01

    In appetitive Pavlovian learning, animals learn to associate discrete cues or environmental contexts with rewarding outcomes, and these cues and/or contexts can potentiate an ongoing instrumental response for reward. Although anatomical substrates underlying cued and contextual learning have been proposed, it remains unknown whether specific…

  6. Screening method for selecting semiconductor substrates having defects below a predetermined level in an oxide layer

    DOEpatents

    Warren, W.L.; Vanheusden, K.J.R.; Schwank, J.R.; Fleetwood, D.M.; Shaneyfelt, M.R.; Winokur, P.S.; Devine, R.A.B.

    1998-07-28

    A method is disclosed for screening or qualifying semiconductor substrates for integrated circuit fabrication. The method comprises the steps of annealing at least one semiconductor substrate at a first temperature in a defect-activating ambient (e.g. hydrogen, forming gas, or ammonia) for sufficient time for activating any defects within on oxide layer of the substrate; measuring a defect-revealing electrical characteristic of at least a portion of the oxide layer for determining a quantity of activated defects therein; and selecting substrates for which the quantity of activated defects is below a predetermined level. The defect-revealing electrical characteristic may be a capacitance-versus voltage (C-V) characteristic or a current-versus-voltage (I-V) characteristic that is dependent on an electrical charge in the oxide layer generated by the activated defects. Embodiments of the present invention may be applied for screening any type of semiconductor substrate or wafer having an oxide layer formed thereon or therein. This includes silicon-on-insulator substrates formed by a separation by the implantation of oxygen (SIMOX) process or the bond and etch back silicon-on-insulator (BESOI) process, as well as silicon substrates having a thermal oxide layer or a deposited oxide layer. 5 figs.

  7. Screening method for selecting semiconductor substrates having defects below a predetermined level in an oxide layer

    DOEpatents

    Warren, William L.; Vanheusden, Karel J. R.; Schwank, James R.; Fleetwood, Daniel M.; Shaneyfelt, Marty R.; Winokur, Peter S.; Devine, Roderick A. B.

    1998-01-01

    A method for screening or qualifying semiconductor substrates for integrated circuit fabrication. The method comprises the steps of annealing at least one semiconductor substrate at a first temperature in a defect-activating ambient (e.g. hydrogen, forming gas, or ammonia) for sufficient time for activating any defects within on oxide layer of the substrate; measuring a defect-revealing electrical characteristic of at least a portion of the oxide layer for determining a quantity of activated defects therein; and selecting substrates for which the quantity of activated defects is below a predetermined level. The defect-revealing electrical characteristic may be a capacitance-versus-voltage (C-V) characteristic or a current-versus-voltage (I-V) characteristic that is dependent on an electrical charge in the oxide layer generated by the activated defects. Embodiments of the present invention may be applied for screening any type of semiconductor substrate or wafer having an oxide layer formed thereon or therein. This includes silicon-on-insulator substrates formed by a separation by the implantation of oxygen (SIMOX) process or the bond and etch back silicon-on-insulator (BESOI) process, as well as silicon substrates having a thermal oxide layer or a deposited oxide layer.

  8. Is My Child's Appetite Normal?

    MedlinePlus

    ... normal way, not overeat. That is a good habit for lifelong health. Provided by NIBBLES FOR HEALTH 17 Nutrition Newsletters for Parents of Young Children, USDA, Food and Nutrition Service Is My Child’s Appetite Normal? ...

  9. Overlay coating degradation by simultaneous oxidation and coating/substrate interdiffusion. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Nesbitt, J. A.

    1983-01-01

    Degradation of NiCrAlZr overlay coatings on various NiCrAl substrates was examined after cyclic oxidation. Concentration/distance profiles were measured in the coating and substrate after various oxidation exposures at 1150 C. For each stubstrate, the Al content in the coating decreased rapidly. The concentration/distance profiles, and particularly that for Al, reflected the oxide spalling resistance of each coated substrate. A numerical model was developed to simulate diffusion associated with overlay-coating degradation by oxidation and coating/substrate interdiffusion. Input to the numerical model consisted of the Cr and Al content of the coating and substrate, ternary diffusivities, and various oxide spalling parameters. The model predicts the Cr and Al concentrations in the coating and substrate after any number of oxidation/thermal cycles. The numerical model also predicts coating failure based on the ability of the coating to supply sufficient Al to the oxide scale. The validity of the model was confirmed by comparison of the predicted and measured concentration/distance profiles. The model was subsequently used to identify the most critical system parameters affecting coating life.

  10. Obesity and Appetite Control

    PubMed Central

    Suzuki, Keisuke; Jayasena, Channa N.; Bloom, Stephen R.

    2012-01-01

    Obesity is one of the major challenges to human health worldwide; however, there are currently no effective pharmacological interventions for obesity. Recent studies have improved our understanding of energy homeostasis by identifying sophisticated neurohumoral networks which convey signals between the brain and gut in order to control food intake. The hypothalamus is a key region which possesses reciprocal connections between the higher cortical centres such as reward-related limbic pathways, and the brainstem. Furthermore, the hypothalamus integrates a number of peripheral signals which modulate food intake and energy expenditure. Gut hormones, such as peptide YY, pancreatic polypeptide, glucagon-like peptide-1, oxyntomodulin, and ghrelin, are modulated by acute food ingestion. In contrast, adiposity signals such as leptin and insulin are implicated in both short- and long-term energy homeostasis. In this paper, we focus on the role of gut hormones and their related neuronal networks (the gut-brain axis) in appetite control, and their potentials as novel therapies for obesity. PMID:22899902

  11. Application of a mixed metal oxide catalyst to a metallic substrate

    NASA Technical Reports Server (NTRS)

    Sevener, Kathleen M. (Inventor); Lohner, Kevin A. (Inventor); Mays, Jeffrey A. (Inventor); Wisner, Daniel L. (Inventor)

    2009-01-01

    A method for applying a mixed metal oxide catalyst to a metallic substrate for the creation of a robust, high temperature catalyst system for use in decomposing propellants, particularly hydrogen peroxide propellants, for use in propulsion systems. The method begins by forming a prepared substrate material consisting of a metallic inner substrate and a bound layer of a noble metal intermediate. Alternatively, a bound ceramic coating, or frit, may be introduced between the metallic inner substrate and noble metal intermediate when the metallic substrate is oxidation resistant. A high-activity catalyst slurry is applied to the surface of the prepared substrate and dried to remove the organic solvent. The catalyst layer is then heat treated to bind the catalyst layer to the surface. The bound catalyst layer is then activated using an activation treatment and calcinations to form the high-activity catalyst system.

  12. Determination of interfacial adhesion strength between oxide scale and substrate for metallic SOFC interconnects

    NASA Astrophysics Data System (ADS)

    Sun, X.; Liu, W. N.; Stephens, E.; Khaleel, M. A.

    The interfacial adhesion strength between the oxide scale and the substrate is crucial to the reliability and durability of metallic interconnects in solid oxide fuel cell (SOFC) operating environments. It is necessary, therefore, to establish a methodology to quantify the interfacial adhesion strength between the oxide scale and the metallic interconnect substrate, and furthermore to design and optimize the interconnect material as well as the coating materials to meet the design life of an SOFC system. In this paper, we present an integrated experimental/analytical methodology for quantifying the interfacial adhesion strength between the oxide scale and a ferritic stainless steel interconnect. Stair-stepping indentation tests are used in conjunction with subsequent finite element analyses to predict the interfacial strength between the oxide scale and Crofer 22 APU substrate.

  13. Nitrosyl-Heme Structures of Bacillus subtilis Nitric Oxide Synthase Have Implications for Understanding Substrate Oxidation

    SciTech Connect

    Pant,K.; Crane, B.

    2006-01-01

    The crystal structures of nitrosyl-heme complexes of a prokaryotic nitric oxide synthase (NOS) from Bacillus subtilis (bsNOS) reveal changes in active-site hydrogen bonding in the presence of the intermediate N{sup {omega}}-hydroxy-L-arginine (NOHA) compared to the substrate L-arginine (L-Arg). Correlating with a Val-to-Ile residue substitution in the bsNOS heme pocket, the Fe(II)-NO complex with both L-Arg and NOHA is more bent than the Fe(II)-NO, L-Arg complex of mammalian eNOS. Structures of the Fe(III)-NO complex with NOHA show a nearly linear nitrosyl group, and in one subunit, partial nitrosation of bound NOHA. In the Fe(II)-NO complexes, the protonated NOHA N{sup {omega}} atom forms a short hydrogen bond with the heme-coordinated NO nitrogen, but active-site water molecules are out of hydrogen bonding range with the distal NO oxygen. In contrast, the L-Arg guanidinium interacts more weakly and equally with both NO atoms, and an active-site water molecule hydrogen bonds to the distal NO oxygen. This difference in hydrogen bonding to the nitrosyl group by the two substrates indicates that interactions provided by NOHA may preferentially stabilize an electrophilic peroxo-heme intermediate in the second step of NOS catalysis.

  14. Process for depositing an oxide epitaxially onto a silicon substrate and structures prepared with the process

    DOEpatents

    McKee, Rodney A.; Walker, Frederick J.

    1993-01-01

    A process and structure involving a silicon substrate utilizes an ultra high vacuum and molecular beam epitaxy (MBE) methods to grow an epitaxial oxide film upon a surface of the substrate. As the film is grown, the lattice of the compound formed at the silicon interface becomes stabilized, and a base layer comprised of an oxide having a sodium chloride-type lattice structure grows epitaxially upon the compound so as to cover the substrate surface. A perovskite may then be grown epitaxially upon the base layer to render a product which incorporates silicon, with its electronic capabilities, with a perovskite having technologically-significant properties of its own.

  15. Substrate Effects on the High Temperature Oxidation Behavior of a Gold-Based Braze Filler Metal

    SciTech Connect

    Weil, K. Scott; Rice, Joseph P.

    2005-06-01

    Oxidation testing was conducted on a commercial gold-based braze alloy, Gold ABA®, and on zirconia/stainless steel couples joined using this filler metal. Preliminary results reveal that both substrates play a significant role in determining the overall oxidation behavior of the brazed joint.

  16. Substrate Effects on the High Temperature Oxidation Behavior of a Gold-Based Braze Filler Metal

    SciTech Connect

    Weil, K. Scott; Rice, Joseph P.

    2005-06-30

    Oxidation testing was conducted on a commercial gold-based braze alloy, Gold ABA, and on zirconia and stainless steel joining couples prepared using this braze filler metal. Preliminary results reveal that both substrates play a significant role in determining the overall oxidation resistance of the brazed joint.

  17. Direct growth of cerium oxide nanorods on diverse substrates for superhydrophobicity and corrosion resistance

    NASA Astrophysics Data System (ADS)

    Cho, Young Jun; Jang, Hanmin; Lee, Kwan-Soo; Kim, Dong Rip

    2015-06-01

    Superhydrophobic surfaces with anti-corrosion properties have attracted great interest in many industrial fields, particularly to enhance the thermal performance of offshore applications such as heat exchangers, pipelines, power plants, and platform structures. Nanostructures with hydrophobic materials have been widely utilized to realize superhydrophobicity of surfaces, and cerium oxide has been highlighted due to its good corrosion resistive and intrinsically hydrophobic properties. However, few studies of direct growth of cerium oxide nanostructures on diverse substrates have been reported. Herein we report a facile hydrothermal method to directly grow cerium oxide nanorods on diverse substrates, such as aluminum alloy, stainless steel, titanium, and silicon. Diverse substrates with cerium oxide nanorods exhibited superhydrophobicity with no hydrophobic modifiers on their surfaces, and showed good corrosion resistive properties in corrosive medium. We believe our method could pave the way for realization of scalable and sustainable corrosion resistive superhydrophobic surfaces in many industrial fields.

  18. Rare earth zirconium oxide buffer layers on metal substrates

    DOEpatents

    Williams, Robert K.; Paranthaman, Mariappan; Chirayil, Thomas G.; Lee, Dominic F.; Goyal, Amit; Feenstra, Roeland

    2001-01-01

    A laminate article comprises a substrate and a biaxially textured (RE.sub.x A.sub.(1-x)).sub.2 O.sub.2-(x/2) buffer layer over the substrate, wherein 0substrate can be a biaxially textured metal, such as nickel. A method of forming the laminate article is also disclosed.

  19. Fracture toughness of solid oxide fuel cell anode substrates determined by a double-torsion technique

    NASA Astrophysics Data System (ADS)

    Pećanac, G.; Wei, J.; Malzbender, J.

    2016-09-01

    Planar solid oxide fuel cell anode substrates are exposed to high mechanical loads during assembly, start-up, steady-state operation and thermal cycling. Hence, characterization of mechanical stability of anode substrates under different oxidation states and at relevant temperatures is essential to warrant a reliable operation of solid oxide fuel cells. As a basis for mechanical assessment of brittle supports, two most common anode substrate material variants, NiO-3YSZ and NiO-8YSZ, were analyzed in this study with respect to their fracture toughness at room temperature and at a typical stack operation temperature of 800 °C. The study considered both, oxidized and reduced materials' states, where also an outlook is given on the behavior of the re-oxidized state that might be induced by malfunctions of sealants or other functional components. Aiming at the improvement of material's production, different types of warm pressed and tape cast NiO-8YSZ substrates were characterized in oxidized and reduced states. Overall, the results confirmed superior fracture toughness of 3YSZ compared to 8YSZ based composites in the oxidized state, whereas in the reduced state 3YSZ based composites showed similar fracture toughness at room temperature, but a higher value at 800 °C compared to 8YSZ based composites. Complementary microstructural analysis aided the interpretation of mechanical characterization.

  20. Growth of indium oxide nanowalls on patterned conducting substrates: towards direct fabrication of gas sensors.

    PubMed

    Chen, Changlong; Wei, Yuling; Sun, Guoxin; Shao, Baiqi

    2012-05-01

    Nanowall materials are ideal two-dimensional structures with high surface-to-volume ratios and open edge geometries. We first report on the growth and characterization of indium oxide nanowalls on transparent and conducting indium tin oxide substrates. The nanosheets that compose the nanowalls are single-crystalline and are approximately 8 nm in thickness. The density and the lateral dimensions of the nanosheets on the substrate can be controlled by the growth time. Adopting a bridgework-like strategy, we directly construct indium oxide nanowall gas sensors on the patterned indium tin oxide substrates. The pattern lines on the substrates are etched using transparent plastic adhesive tape as shadow mask, which is both simple and cheap in comparison with the conventional photolithography technique. The sensors exhibit fast response/recovery behavior and good reproducibility to NO(2) gas under mild testing conditions, such as room temperature, ambient pressure, dry air background, and 1.5 V dc bias, and can achieve a detection limit as low as 50 ppb. We propose an assumption that the gas adsorption is composed of deep adsorption and probe adsorption to explain the interesting gas-sensing behavior of the indium oxide nanowalls. We suggest that the work reported herein, including the facile growth of indium oxide nanowalls, the bridgework-like strategy to directly construct electronic devices, and the high gas-sensing performance of the indium oxide nanowalls sensors, is a significant step towards the real applications of novel semiconductor nanostructures. PMID:22328146

  1. The amphetamine appetite suppressant saga.

    PubMed

    2004-02-01

    (1) In 1999, all amphetamine derivatives still sold in France as appetite suppressants were withdrawn from the market because of serious cardiovascular adverse effects. Sibutramine, marketed in France since 2001, is closely related to this group of drugs. (2) The adverse effects shared by these drugs are mainly neuropsychiatric (due to a psychostimulant action) and cardiovascular (arterial hypertension and tachycardia). (3) More specific cardiovascular adverse effects, such as pulmonary hypertension and severe cardiac valve damage, emerged after several years of use. The first reports date back to the 1960s. (4) The pulmonary hypertension associated with appetite suppressants can be fatal or necessitate transplantation. (5) Cardiac valve damage due to appetite suppressants is generally irreversible and sometimes requires surgery. PMID:15055225

  2. H2 oxidation versus organic substrate oxidation in non-heme iron mediated reactions with H2O2.

    PubMed

    Hassanpour, Azin; Acuña-Parés, Ferran; Luis, Josep M; Cusso, Olaf; Morales de la Rosa, Silvia; Campos-Martín, José Miguel; Fierro, Jose L G; Costas, Miquel; Lloret-Fillol, Julio; Mas-Ballesté, Rubén

    2015-10-18

    Herein we show that species generated upon reaction of α-[Fe(CF3SO3)2(BPMCN)] (BPMCN = N,N'-bis(2-pyridylmethyl)-trans-1,2-diaminocyclohexane) with H2O2 (putatively [Fe(V)(O)(OH)(BPMCN)]) is able to efficiently oxidize H2 to H2O even in the presence of organic substrates, while species formed in the presence of acetic acid (putatively [Fe(V)(O)(OAc)(BPMCN)]) prefer organic substrate oxidation over H2 activation. Mechanistic implications have been analysed with the aid of computational methods. PMID:26311021

  3. Electrochemically deposited gallium oxide nanostructures on silicon substrates

    PubMed Central

    2014-01-01

    We report a synthesis of β-Ga2O3 nanostructures on Si substrate by electrochemical deposition using a mixture of Ga2O3, HCl, NH4OH, and H2O. The presence of Ga3+ ions contributed to the deposition of Ga2O3 nanostructures on the Si surface with the assistance of applied potentials. The morphologies of the grown structures strongly depended on the molarity of Ga2O3 and pH level of electrolyte. β-Ga2O3 nanodot-like structures were grown on Si substrate at a condition with low molarity of Ga2O3. However, Ga2O3 nanodot structures covered with nanorods on top of their surfaces were obtained at higher molarity, and the densities of nanorods seem to increase with the decrease of pH level. High concentration of Ga3+ and OH- ions may promote the reaction of each other to produce Ga2O3 nanorods in the electrolyte. Such similar nature of Ga2O3 nanorods was also obtained by using hydrothermal process. The grown structures seem to be interesting for application in electronic and optoelectronic devices as well as to be used as a seed structure for subsequent chemical synthesis of GaN by thermal transformation method. PMID:24629107

  4. Complete coverage of reduced graphene oxide on silicon dioxide substrates

    NASA Astrophysics Data System (ADS)

    Huang, Jingfeng; Melanie, Larisika; Chen, Hu; Steve, Faulkner; Myra, A. Nimmo; Christoph, Nowak; Alfred Tok Iing, Yoong

    2014-08-01

    Reduced graphene oxide (RGO) has the advantage of an aqueous and industrial-scale production route. No other approaches can rival the RGO field effect transistor platform in terms of cost (oxide with ethanol, carbon islets are deposited preferentially at the edges of existing flakes. With a 2-h treatment, the standard deviation in electrical resistance of the treated chips can be reduced by 99.95%. Thus this process could enable RGO to be used in practical electronic devices.

  5. Oxidative Attack of Carbon/Carbon Substrates through Coating Pinholes

    NASA Technical Reports Server (NTRS)

    Jacobson, Nathan S.; Leonhardt, Todd; Curry, Donald; Rapp, Robert A.

    1998-01-01

    A critical issue with oxidation protected carbon/carbon composites used for spacecraft thermal protection is the formation of coating pinholes. In laboratory experiments, artificial pinholes were drilled through SiC-coatings on a carbon/carbon material and the material was oxidized at 600, 1000, and 1400 C at reduced pressures of air. The attack of the carbon/carbon was quantified by both weight loss and a novel cross-sectioning technique. A two-zone, one dimensional diffusion control model was adapted to analyze this problem. Agreement of the model with experiment was reasonable at 1000 and 1400 C; however results at lower temperatures show clear deviations from the theory suggesting that surface reaction control plays a role.

  6. Process for depositing epitaxial alkaline earth oxide onto a substrate and structures prepared with the process

    DOEpatents

    McKee, Rodney A.; Walker, Frederick J.

    1996-01-01

    A process and structure involving a silicon substrate utilize molecular beam epitaxy (MBE) and/or electron beam evaporation methods and an ultra-high vacuum facility to grow a layup of epitaxial alkaline earth oxide films upon the substrate surface. By selecting metal constituents for the oxides and in the appropriate proportions so that the lattice parameter of each oxide grown closely approximates that of the substrate or base layer upon which oxide is grown, lattice strain at the film/film or film/substrate interface of adjacent films is appreciably reduced or relieved. Moreover, by selecting constituents for the oxides so that the lattice parameters of the materials of adjacent oxide films either increase or decrease in size from one parameter to another parameter, a graded layup of films can be grown (with reduced strain levels therebetween) so that the outer film has a lattice parameter which closely approximates that of, and thus accomodates the epitaxial growth of, a pervoskite chosen to be grown upon the outer film.

  7. [Oxidation of sulfur-containing substrates by aboriginal and experimentally designed microbial communities].

    PubMed

    Pivovarova, T A; Bulaev, A G; Roshchupko, P V; Belyĭ, A V; Kondrat'eva, T F

    2012-01-01

    Aboriginal and experimental (constructed of pure microbial cultures) communities of acidophilic chemolithotrophs have been studied. The oxidation of elemental sulfur, sodium thiosulfate, and potassium tetrathionate as sole sources of energy has been monitored. The oxidation rate of the experimental community is higher as compared to the aboriginal community isolated from a flotation concentrate of pyrrhotine-containing pyrite-arsenopyrite gold-arsenic sulfide ore. The degree of oxidation of the mentioned S substrates amounts to 17.91, 68.30, and 93.94% for the experimental microbial community and to 10.71, 56.03, and 79.50% for the aboriginal community, respectively. The degree of oxidation of sulfur sulfide forms in the ore flotation concentrate is 59.15% by the aboriginal microbial community and 49.40% by the experimental microbial community. Despite a higher rate of oxidation of S substrates as a sole source of energy by the experimental microbial community, the aboriginal community oxidizes S substrates at a higher rate in the flotation concentrate of pyrrhotine-containing pyrite-arsenopyrite gold-arsenic sulfide ore, from which it was isolated. Bacterial-chemical oxidation of the flotation concentrate by the aboriginal microbial community allows for the extraction of an additional 32.3% of gold from sulfide minerals, which is by 5.7% larger compared to the yield obtained by the experimental microbial community. PMID:23330391

  8. Electrochemical oxidation of imazapyr with BDD electrode in titanium substrate.

    PubMed

    Souza, F L; Teodoro, T Q; Vasconcelos, V M; Migliorini, F L; Lima Gomes, P C F; Ferreira, N G; Baldan, M R; Haiduke, R L A; Lanza, M R V

    2014-12-01

    In this work we have studied the treatment of imazapyr by electrochemical oxidation with boron-doped diamond anode. Electrochemical degradation experiments were performed in a one-compartment cell containing 0.45 L of commercial formulations of herbicide in the pH range 3.0-10.0 by applying a density current between 10 and 150 mA cm(-2) and in the temperature range 25-45 °C. The maximum current efficiencies were obtained at lower current densities since the electrochemical system is under mass transfer control. The mineralization rate increased in acid medium and at higher temperatures. The treatment was able to completely degrade imazapyr in the range 4.6-100.0 mg L(-1), although the current charge required rises along with the increasing initial concentration of the herbicide. Toxicity analysis with the bioluminescent bacterium Vibrio fischeri showed that at higher pollutant concentrations the toxicity was reduced after the electrochemical treatment. To clarify the reaction pathway for imazapyr mineralization by OH radicals, LC-MS/MS analyses we performed together with a theoretical study. Ions analysis showed the formation of high levels of ammonium in the cathode. The main final products of the electrochemical oxidation of imazapyr with diamond thin film electrodes are formic, acetic and butyric acids. PMID:25461923

  9. Laser patterning of very thin indium tin oxide thin films on PET substrates

    NASA Astrophysics Data System (ADS)

    McDonnell, C.; Milne, D.; Prieto, C.; Chan, H.; Rostohar, D.; O'Connor, G. M.

    2015-12-01

    This work investigates the film removal properties of 30 nm thick Indium Tin Oxide (ITO) thin films, on flexible polyethylene terephthalate (PET) substrates, using 355, 532 and 1064 nm nanosecond pulses (ns), and 343 and 1064 nm femtosecond pulses. The ablation threshold was found to be dependent on the applied wavelength and pulse duration. The surface topography of the laser induced features were examined using atomic force microscopy across the range of wavelengths and pulse durations. The peak temperature, strain and stress tensors were examined in the film and substrate during laser heating, using finite element computational methods. Selective removal of the thin ITO film from the polymer substrate is possible at all wavelengths except at 266 nm, were damage to substrate is observed. The damage to the substrate results in periodic surface structures (LIPPS) on the exposed PET, with a period of twice the incident wavelength. Fragmented crater edges are observed at all nanosecond pulse durations. Film removal using 1030 nm femtosecond pulses results in clean crater edges, however, minor 5 nm damage to the substrate is also observed. The key results show that film removal for ITO on PET, is through film de-lamination across all wavelengths and pulse durations. Film de-lamination occurs due to thermo-elastic stress at the film substrate interface region, as the polymer substrate expands under heating from direct laser absorption and heat conduction across the film substrate interface.

  10. Effect of substrate temperature on electrochromic properties of spray-deposited Ir-oxide thin films

    NASA Astrophysics Data System (ADS)

    Patil, P. S.; Kawar, R. K.; Sadale, S. B.

    2005-08-01

    Electrochromic iridium oxide thin films were prepared by using a simple and inexpensive spray pyrolysis technique onto fluorine doped tin oxide (FTO)-coated glass substrates, from iridium chloride solution. The substrate temperature was varied between 250 and 400 °C. The as-deposited samples were amorphous. The electrochromic properties of thin films were studied in aqueous electrolyte (0.5N H 2SO 4) using cyclic voltammetry (CV), chronoamperometry (CA) and spectroelectrochemical techniques. The films exhibit anodic electrochromism upon intercalation and deintercalation of H + ions. The colouration efficiency at 630 nm was calculated and found maximum for I 250 sample, owing its hydration.

  11. Oxytocin and appetite.

    PubMed

    Leng, Gareth; Onaka, Tatsushi; Caquineau, Celine; Sabatier, Nancy; Tobin, Vicky A; Takayanagi, Yuki

    2008-01-01

    Oxytocin has potent central effects on feeding behaviour, as well as on social and sexual behaviours, and one likely substrate for its anorectic effect is the ventromedial nucleus of the hypothalamus. This nucleus expresses a high density of oxytocin receptors, but contains very few oxytocin-containing fibres, hence it is a likely target of 'neurohormonal' actions of oxytocin, including possibly oxytocin released from the dendrites of magnocellular oxytocin neurones. As oxytocin release from dendrites is regulated independent of electrical activity and of secretion from the neurohypophysis, exactly how this release is regulated by metabolic and reproduction-related signals remains to be established fully. Intriguingly though, it looks as though this central release of oxytocin from magnocellular neurons might be instrumental in a fundamental shift in motivational behaviour - switching behaviour from being driven by the need to find and consume food, to the need to reproduce. PMID:18655879

  12. Sex difference in substrate oxidation during low-intensity isometric exercise in young adults.

    PubMed

    Sarafian, Delphine; Schutz, Yves; Montani, Jean-Pierre; Dulloo, Abdul G; Miles-Chan, Jennifer L

    2016-09-01

    Low-intensity physical activity is increasingly promoted as an alternative to sedentary behavior. However, much research to date has focused on moderate- to vigorous-intensity physical activity, and in particular dynamic work, with the effect of low-intensity isometric exercise (<4 METs) on substrate utilization yet to be explored. Here we investigate the effects of such exercise on respiratory quotient (RQ) and determine the extent of intra- and inter-individual variability in response. Energy expenditure, RQ, and substrate oxidation were measured by ventilated-hood indirect calorimetry at rest and in response to standardized, intermittent, low-level isometric leg-press exercises at 5 loads (+5, +10, +15, +20, +25 kg) in 26 healthy, young adults. Nine participants repeated the experiment on 3 separate days to assess within-subject, between-day variability. There was no significant difference in energy cost and heart rate responses to low-intensity isometric exercise (<2 METs) between men and women. However, a sex difference was apparent in terms of substrate oxidation - with men increasing both fat and carbohydrate oxidation, and women only increasing fat oxidation while maintaining carbohydrate oxidation at baseline, resting levels. This sex difference was repeatable and persisted when substrate oxidation was adjusted for differences in body weight or body composition. Individual variability in RQ was relatively low, with both intra- and inter-individual coefficients of variation in the range of 3%-6% in both sexes. These results suggest that women preferentially increase fat oxidation during low-level isometric exercise. Whether such physical activity could be incorporated into treatment/prevention strategies aimed at optimizing fat oxidation in women warrants further investigation. PMID:27540628

  13. Protective Effect of Selected Medicinal Plants against Hydrogen Peroxide Induced Oxidative Damage on Biological Substrates.

    PubMed

    Pai Kotebagilu, Namratha; Reddy Palvai, Vanitha; Urooj, Asna

    2014-01-01

    Oxidative stress is developed due to susceptibility of biological substrates to oxidation by generation of free radicals. In degenerative diseases, oxidative stress level can be reduced by antioxidants which neutralize free radicals. Primary objective of this work was to screen four medicinal plants, namely, Andrographis paniculata, Costus speciosus, Canthium parviflorum, and Abrus precatorius, for their antioxidant property using two biological substrates-RBC and microsomes. The antioxidative ability of three solvent extracts, methanol (100% and 80%) and aqueous leaf extracts, was studied at different concentrations by thiobarbituric acid reactive substances method using Fenton's reagent to induce oxidation in the substrates. The polyphenol and flavonoid content were analyzed to relate with the observed antioxidant effect of the extracts. The phytochemical screening indicated the presence of flavonoids, polyphenols, tannins, and β-carotene in the samples. In microsomes, 80% methanol extract of Canthium and Costus and, in RBC, 80% methanol extract of Costus showed highest inhibition of oxidation and correlated well with the polyphenol and flavonoid content. From the results it can be concluded that antioxidants from medicinal plants are capable of inhibiting oxidation in biological systems, suggesting scope for their use as nutraceuticals. PMID:25436152

  14. Thermally-driven structural changes of graphene oxide multilayer films deposited on glass substrate

    NASA Astrophysics Data System (ADS)

    Lazauskas, A.; Baltrusaitis, J.; Grigaliūnas, V.; Guobienė, A.; Prosyčevas, I.; Narmontas, P.; Abakevičienė, B.; Tamulevičius, S.

    2014-11-01

    Graphene oxide (GO) has been recognized as an important intermediate compound for a potential low-cost large-scale graphene-like film fabrication. In this work, graphene oxide multilayer films deposited on glass substrate were reduced using different thermal reduction methods, including low-temperature annealing, flame-induced and laser reduction, and the corresponding surface morphology and structural properties were investigated. These graphene oxide thermal reduction methods strongly affected surface morphology and differently facilitated structural and chemical transformations of graphene oxide. As evidenced by Raman measurements, thermal annealing and laser reduction of graphene oxide produced more ordered graphene-like structure multilayer films. However, surface morphological differences were observed and attributed to the different de-oxidation mechanisms of GO. This Letter provides an important systematic comparison between the GO reduction methods and thermally-driven structural changes they provide to the reduced GO multilayer films obtained.

  15. Benzene oxide is a substrate for glutathione S-transferases.

    PubMed

    Zarth, Adam T; Murphy, Sharon E; Hecht, Stephen S

    2015-12-01

    Benzene is a known human carcinogen which must be activated to benzene oxide (BO) to exert its carcinogenic potential. BO can be detoxified in vivo by reaction with glutathione and excretion in the urine as S-phenylmercapturic acid. This process may be catalyzed by glutathione S-transferases (GSTs), but kinetic data for this reaction have not been published. Therefore, we incubated GSTA1, GSTT1, GSTM1, and GSTP1 with glutathione and BO and quantified the formation of S-phenylglutathione. Kinetic parameters were determined for GSTT1 and GSTP1. At 37 °C, the putative Km and Vmax values for GSTT1 were 420 μM and 450 fmol/s, respectively, while those for GSTP1 were 3600 μM and 3100 fmol/s. GSTA1 and GSTM1 did not exhibit sufficient activity for determination of kinetic parameters. We conclude that GSTT1 is a critical enzyme in the detoxification of BO and that GSTP1 may also play an important role, while GSTA1 and GSTM1 seem to be less important. PMID:26554337

  16. Oxidation of ultrafast radical clock substrate probes by the soluble methane monooxygenase from Methylococcus capsulatus (Bath).

    PubMed

    Valentine, A M; LeTadic-Biadatti, M H; Toy, P H; Newcomb, M; Lippard, S J

    1999-04-16

    Radical clock substrate probes were used to assess the viability of a discrete substrate radical species in the mechanism of hydrocarbon oxidation by the soluble methane monooxygenase (sMMO) from Methylococcus capsulatus (Bath). New substituted cyclopropane probes were used with very fast ring-opening rate constants and other desirable attributes, such as the ability to discriminate between radical and cationic intermediates. Oxidation of these substrates by a reconstituted sMMO system resulted in no rearranged products, allowing an upper limit of 150 fs to be placed on the lifetime of a putative radical species. This limit strongly suggests that there is no such substrate radical intermediate. The two enantiomers of trans-1-methyl-2-phenyl-cyclopropane were prepared, and the regioselectivity of their oxidation to the corresponding cyclopropylmethanol and cyclopropylphenol products was determined. The results are consistent with selective orientation of the two enantiomeric substrates in the hydrophobic cavity at the active site of sMMO, specific models for which were examined by molecular modeling. PMID:10196150

  17. Bovine plasma amine oxidase (PAO) oxidizes substrate by a proton activation mechanism

    SciTech Connect

    Hartmann, C.; Klinman, J.P.

    1986-05-01

    PAO catalyzes the oxidative deamination of amines to aldehydes, concomitant with a 2e/sup -/ reduction of O/sub 2/ to H/sub 2/O/sub 2/. Several investigators have proposed recently that the organic cofactor in PAO is pyrroloquinoline quinone (PQQ), hitherto seen exclusively in prokaryotes. The structure and properties of PQQ predict first, that substrate and PAO will form a covalent adduct and second, that substrate will be oxidized via proton abstraction. In earlier studies from this laboratory, steady state isotope effects, in conjunction with an intrinsic isotope effect, have been shown to provide microscopic rate constants from complex mechanisms. In this study, V, D/sub V/, V/K and /sup D/(V/K) have been measured for the oxidation of a series of nine ring-substituted benzylamines and (1-/sup 2/H/sub 2/)-benzylamines with PAO. The series of substrates was chosen to minimize collinearity in the electronic and hydrophobic properties of ring substituents. Computed rate constants for the C-H bond cleavage step indicate a strong correlation with electron withdrawing substituents, rho = 1.3, confirming the formation of a discrete carbanion intermediate upon substrate activation. Additional studies are in progress, with the objective of trapping and characterizing the putative adduct between PAO and substrates.

  18. Species identification of Aeromonas strains based on carbon substrate oxidation profiles.

    PubMed Central

    Carnahan, A M; Joseph, S W; Janda, J M

    1989-01-01

    Twenty clinical strains each of Aeromonas hydrophila, Aeromonas caviae, and Aeromonas sobria were evaluated for their abilities to oxidize one or more of 95 carbon sources on a GN Microplate (BIOLOG, Hayward, Calif.). Nine substrates yielded good, discriminatory values for the three species tested. The panel appears to be useful for the species identification of Aeromonas isolates originating from human material. PMID:2778077

  19. Microplasmas for direct, substrate-independent deposition of nanostructured metal oxides

    NASA Astrophysics Data System (ADS)

    Mackie, Katherine E.; Pebley, Andrew C.; Butala, Megan M.; Zhang, Jinping; Stucky, Galen D.; Gordon, Michael J.

    2016-07-01

    A general, substrate-independent method for plasma deposition of nanostructured, crystalline metal oxides is presented. The technique uses a flow-through, micro-hollow cathode plasma discharge (supersonic microplasma jet) with a "remote" ring anode to deliver a highly directed flux of growth species to the substrate. A diverse range of nanostructured materials (e.g., CuO, α-Fe2O3, and NiO) can be deposited on any room temperature surface, e.g., conductors, insulators, plastics, fibers, and patterned surfaces, in a conformal fashion. The effects of deposition conditions, substrate type, and patterning on film morphology, nanostructure, and surface coverage are highlighted. The synthesis approach presented herein provides a general and tunable method to deposit a variety of functional and hierarchical metal oxide materials on many different surfaces. High surface area, conversion-type CuO electrodes for Li-ion batteries are demonstrated as a proof-of-concept example.

  20. PERIPHERAL MECHANISMS IN APPETITE REGULATION

    PubMed Central

    Camilleri, Michael

    2014-01-01

    Peripheral mechanisms in appetite regulation include the motor functions of the stomach, such as the rate of emptying and accommodation, which convey symptoms of satiation to the brain. The rich repertoire of peripherally released peptides and hormones provides feedback from the arrival of nutrients in different regions of the gut from where they are released to exert effects on satiation, or regulate metabolism through their incretin effects. Ultimately, these peripheral factors provide input to the highly organized hypothalamic circuitry and vagal complex of nuclei to determine cessation of energy intake during meal ingestion, and the return of appetite and hunger after fasting. Understanding these mechanisms is key to the physiological control of feeding and the derangements that occur in obesity and their restoration with treatment (as demonstrated by the effects of bariatric surgery). PMID:25241326

  1. Copper substrate as a catalyst for the oxidation of chemical vapor deposition-grown graphene

    SciTech Connect

    Li, Zhiting; Zhou, Feng; Parobek, David; Shenoy, Ganesh J.; Muldoon, Patrick; Liu, Haitao

    2015-04-15

    We report the catalytic effect of copper substrate on graphene–oxygen reaction at high temperature. Previous studies showed that graphene grown on copper are mostly defect-free with strong oxidation resistance. We found that a freshly prepared copper-supported graphene sample can be completely oxidized in trace amount of oxygen (<3 ppm) at 600 °C within 2 h. Both X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) suggest that upon ambient air exposure, oxygen molecules diffuse into the space between graphene and copper, resulting in the formation of copper oxide which acts as catalytic sites for the graphene-oxygen reaction. This result has important implications for the characterization, processing, and storage of copper-supported graphene samples. - Graphical abstract: The copper substrate enhances the thermel oxidation of single-layer graphene. - Highlights: • A copper-supported graphene can be oxidized in Ar (O{sub 2}<3 ppm, 600 °C, 2 h). • O{sub 2} intercalates between graphene and copper upon exposure to air. • The copper foil should not be considered as an inert substrate.

  2. Copper Oxide Substrates and Epitaxial Copper Oxide/Zinc Oxide Thin Film Heterostructures for Solar Energy Conversion

    NASA Astrophysics Data System (ADS)

    Darvish, Davis Solomon

    Future fossil fuel scarcity and environmental degradation have demonstrated the need for renewable, low-carbon sources of energy to power an increasingly industrialized world. Solar energy with its infinite supply makes it an extraordinary resource that should not go unused. However with current materials, adoption is limited by cost and so a paradigm shift must occur to get everyone on the same page embracing solar technology. Cuprous Oxide (Cu2O) is a promising earth abundant material that can be a great alternative to traditional thin-film photovoltaic materials like CIGS, CdTe, etc. We have prepared Cu 2O bulk substrates by the thermal oxidation of copper foils as well Cu2O thin films deposited via plasma-assisted Molecular Beam Epitaxy. From preliminary Hall measurements it was determined that Cu2O would need to be doped extrinsically. This was further confirmed by simulations of ZnO/Cu2O heterojunctions. A cyclic interdependence between, defect concentration, minority carrier lifetime, film thickness, and carrier concentration manifests itself a primary reason for why efficiencies greater than 4% has yet to be realized. Our growth methodology for our thin-film heterostructures allow precise control of the number of defects that incorporate into our film during both equilibrium and nonequilibrium growth. We also report process flow/device design/fabrication techniques in order to create a device. A typical device without any optimizations exhibited open-circuit voltages Voc, values in excess 500mV; nearly 18% greater than previous solid state devices.

  3. Effect of Phosphate and Uncouplers on Substrate Transport and Oxidation by Isolated Corn Mitochondria 1

    PubMed Central

    Day, David A.; Hanson, John B.

    1977-01-01

    A study was made to determine conditions under which malate oxidation rates in corn (Zea mays L.) mitochondria are limited by transport processes. In the absence of added ADP, inorganic phosphate increased malate oxidation rates by processes inhibited by mersalyl and oligomycin, but phosphate did not stimulate uncoupled respiration. However, the uncoupled oxidation rates were inhibited by butylmalonate and mersalyl. When uncoupler was added prior to substrate, subsequent O2 uptake rates were reduced when malate and succinate, but not exogenous NADH, were used. Uncoupler and butylmalonate also inhibited swelling in malate solutions and malate accumulation by these mitochondria, which were found to have a high endogenous phosphate content. Addition of uncoupler after malate or succinate produced an initial rapid oxidation which declined as the mitochondria lost solute and contracted. This decline was not affected by addition of ADP or AMP, and was not observed when exogenous NADH was substrate. Increasing K+ permeability with valinomycin increased the P-trifluoromethoxy (carboxylcyanide)phenyl hydrazone inhibition. Kinetic studies showed the slow rate of malate oxidation in the presence of uncoupler to be characterized by a high Km and a low Vmax, probably reflecting a diffusion-limited process. The results indicate that rapid malate and succinate oxidation require the operation of both the phosphate and dicarboxylate transporters, which in turn depend on maintenance of a proton motive force across the inner membrane. In addition, phosphate can stimulate acceptorless malate oxidation by reaction with the coupling mechanism, and in uncoupled mitochondria which are depleted of substrate there is a slow rate of oxidation which appears to be limited by diffusive entry. PMID:16659803

  4. Effects of hydrolysed casein, intact casein and intact whey protein on energy expenditure and appetite regulation: a randomised, controlled, cross-over study.

    PubMed

    Bendtsen, Line Q; Lorenzen, Janne K; Gomes, Sisse; Liaset, Bjørn; Holst, Jens J; Ritz, Christian; Reitelseder, Søren; Sjödin, Anders; Astrup, Arne

    2014-10-28

    Casein and whey differ in amino acid composition and in the rate of absorption; however, the absorption rate of casein can be increased to mimic that of whey by exogenous hydrolysis. The objective of the present study was to compare the effects of hydrolysed casein (HC), intact casein (IC) and intact whey (IW) on energy expenditure (EE) and appetite regulation, and thereby to investigate the influence of amino acid composition and the rate of absorption. In the present randomised cross-over study, twenty-four overweight and moderately obese young men and women consumed three isoenergetic dietary treatments that varied in protein source. The study was conducted in a respiration chamber, where EE, substrate oxidation and subjective appetite were measured over 24 h at three independent visits. Moreover, blood and urine samples were collected from the participants. The results showed no differences in 24 h and postprandial EE or appetite regulation. However, lipid oxidation, estimated from the respiratory quotient (RQ), was found to be higher after consumption of IW than after consumption of HC during daytime (P= 0·014) as well as during the time after the breakfast meal (P= 0·008) when the food was provided. Likewise, NEFA concentrations were found to be higher after consumption of IW than after consumption of HC and IC (P< 0·01). However, there was no overall difference in the concentration of insulin or glucagon-like peptide 1. In conclusion, dietary treatments when served as high-protein mixed meals induced similar effects on EE and appetite regulation, except for lipid oxidation, where RQ values suggest that it is higher after consumption of IW than after consumption of HC. PMID:25191896

  5. Substrate inhibition: Oxidation of D-sorbitol and D-mannitol by potassium periodate in alkaline medium

    NASA Astrophysics Data System (ADS)

    Lakshman Kumar, Y.; Venkata Nadh, R.; Radhakrishnamurti, P. S.

    2014-05-01

    In the oxidation of D-sorbitol and D-mannitol by potassium periodate in alkaline media, substrate inhibition was observed with both substrates, i.e., a decrease in the rate of the reaction was observed with an increase in the concentration of substrate. The substrate inhibition was attributed to the formation of stable complex between the substrate and periodate. The reactions were found to be first order in case of periodate and a positive fractional order with hydroxide ions. Arrhenius parameters were calculated for the oxidation of sorbitol and mannitol by potassium periodate in alkali media.

  6. In-situ Reflectance Monitoring of GaSb Substrate Oxide Desorption

    SciTech Connect

    C.J. Vineis; C.A. Wang; K.F. Jensen

    2000-08-21

    The use of specular reflectance to monitor GaSb substrate oxide desorption in-situ is reported. Substrates were loaded into the organometallic vapor phase epitaxy reactor either as-received (epi-ready) or after receiving a solvent degrease, acid etch and rinse. A variety of surface preparations and anneal conditions were investigated. HCL was used as the etchant, and in certain cases was followed by an additional etch in Br{sub 2}-HCl-HNO{sub 3}-CH{sub 3}COOH for comparison. Rinse comparisons included 2-propanol, methanol, and deionized water. Substrates were heated to either 525, 550, or 575 C. Features observed in the in-situ reflectance associated with the oxide desorption process were interpreted based on the starting oxide chemistry and thickness. Based on in-situ reflectance and ex-situ atomic force microscopy data, a recommendation on a reproducible GaSb substrate preparation technique suitable for high-quality epitaxial growth is suggested.

  7. Structure, stability and electrochromic properties of polyaniline film covalently bonded to indium tin oxide substrate

    NASA Astrophysics Data System (ADS)

    Zhang, Wenzhi; Ju, Wenxing; Wu, Xinming; Wang, Yan; Wang, Qiguan; Zhou, Hongwei; Wang, Sumin; Hu, Chenglong

    2016-03-01

    Indium tin oxide (ITO) substrate was modified with 4-aminobenzylphosphonic acid (ABPA), and then the polyaniline (PANI) film covalently bonded to ITO substrate was prepared by the chemical oxidation polymerization. X-ray photoelectron spectroscopy (XPS), attenuated total reflection infrared (ATR-IR) spectroscopy, and atomic force microscopy (AFM) measurements demonstrated that chemical binding was formed between PANI and ABPA-modified ITO surface, and the maximum thickness of PANI layer is about 30 nm. The adhesive strength of PANI film on ITO substrate was tested by sonication. It was found that the film formed on the modified ITO exhibited a much better stability than that on bare one. Cyclic voltammetry (CV) and UV-vis spectroscopy measurements indicated that the oxidative potentials of PANI film on ABPA-modified ITO substrate were decreased and the film exhibited high electrochemical activities. Moreover, the optical contrast increased from 0.58 for PANI film (without ultrasound) to 1.06 for PANI film (after ultrasound for 60 min), which had an over 83% enhancement. The coloration time was 20.8 s, while the bleaching time was 19.5 s. The increase of electrochromic switching time was due to the lower ion diffusion coefficient of the large cation of (C4H9)4N+ under the positive and negative potentials as comparison with the small Li+ ion.

  8. Protective Effect of Selected Medicinal Plants against Hydrogen Peroxide Induced Oxidative Damage on Biological Substrates

    PubMed Central

    Pai Kotebagilu, Namratha; Reddy Palvai, Vanitha

    2014-01-01

    Oxidative stress is developed due to susceptibility of biological substrates to oxidation by generation of free radicals. In degenerative diseases, oxidative stress level can be reduced by antioxidants which neutralize free radicals. Primary objective of this work was to screen four medicinal plants, namely, Andrographis paniculata, Costus speciosus, Canthium parviflorum, and Abrus precatorius, for their antioxidant property using two biological substrates—RBC and microsomes. The antioxidative ability of three solvent extracts, methanol (100% and 80%) and aqueous leaf extracts, was studied at different concentrations by thiobarbituric acid reactive substances method using Fenton's reagent to induce oxidation in the substrates. The polyphenol and flavonoid content were analyzed to relate with the observed antioxidant effect of the extracts. The phytochemical screening indicated the presence of flavonoids, polyphenols, tannins, and β-carotene in the samples. In microsomes, 80% methanol extract of Canthium and Costus and, in RBC, 80% methanol extract of Costus showed highest inhibition of oxidation and correlated well with the polyphenol and flavonoid content. From the results it can be concluded that antioxidants from medicinal plants are capable of inhibiting oxidation in biological systems, suggesting scope for their use as nutraceuticals. PMID:25436152

  9. EXAMINATION OF THE OXIDATION PROTECTION OF ZINC COATINGS FORMED ON COPPER ALLOYS AND STEEL SUBSTRATES

    SciTech Connect

    Papazoglou, M.; Chaliampalias, D.; Vourlias, G.; Pavlidou, E.; Stergioudis, G.; Skolianos, S.

    2010-01-21

    The exposure of metallic components at aggressive high temperature environments, usually limit their usage at similar application because they suffer from severe oxidation attack. Copper alloys are used in a wide range of high-quality indoor and outdoor applications, statue parts, art hardware, high strength and high thermal conductivity applications. On the other hand, steel is commonly used as mechanical part of industrial set outs or in the construction sector due to its high mechanical properties. The aim of the present work is the examination of the oxidation resistance of pack cementation zinc coatings deposited on copper, leaded brass and steel substrates at elevated temperature conditions. Furthermore, an effort made to make a long-term evaluation of the coated samples durability. The oxidation results showed that bare substrates appear to have undergone severe damage comparing with the coated ones. Furthermore, the mass gain of the uncoated samples was higher than this of the zinc covered ones. Particularly zinc coated brass was found to be more resistant to oxidation conditions in which it was exposed as it has the lower mass gain as compared to the bare substrates and zinc coated copper. Zinc coated steel was also proved to be more resistive than the uncoated steel.

  10. Low-voltage protonic/electronic hybrid indium zinc oxide synaptic transistors on paper substrates

    NASA Astrophysics Data System (ADS)

    Wu, Guodong; Wan, Changjin; Zhou, Jumei; Zhu, Liqiang; Wan, Qing

    2014-03-01

    Low-voltage (1.5 V) indium zinc oxide (IZO)-based electric-double-layer (EDL) thin-film transistors (TFTs) gated by nanogranular proton conducting SiO2 electrolyte films are fabricated on paper substrates. Both enhancement-mode and depletion-mode operation are obtained by tuning the thickness of the IZO channel layer. Furthermore, such flexible IZO protonic/electronic hybrid EDL TFTs can be used as artificial synapses, and synaptic stimulation response and short-term synaptic plasticity function are demonstrated. The protonic/electronic hybrid EDL TFTs on paper substrates proposed here are promising for low-power flexible paper electronics, artificial synapses and bioelectronics.

  11. Highly flexible, hybrid-structured indium tin oxides for transparent electrodes on polymer substrates

    SciTech Connect

    Triambulo, Ross E.; Kim, Jung-Hoon; Park, Jin-Woo; Na, Min-Young; Chang, Hye-Jung

    2013-06-17

    We developed highly flexible, hybrid-structured crystalline indium tin oxide (ITO) for use as transparent electrodes on polymer substrates by embedding Ag nanoparticles (AgNPs) into the substrate. The hybrid ITO consists of domains in one orientation grown on the AgNPs and a matrix of the other orientation. The domains are stronger than the matrix and function as barriers to crack propagation. As a result, both the critical bending radius (r{sub c}) (under which the resistivity change ({Delta}{rho}) is less than a given value) and the change in {Delta}{rho} with decreasing r significantly decreased in the hybrid ITO compared with homogenous ITO.

  12. X-ray Characterisation of Zinc Oxide (ZnO) Single Crystal Substrates

    SciTech Connect

    Dhanaraj, G.; Raghothamachar, B; Dudley, M

    2010-01-01

    Single crystal substrates of low defect density are paramount for fully realizing the numerous applications of zinc oxide (ZnO) wide bandgap semiconductors. While ZnO substrates are commercially available from various vendors, very little information is available on the structural properties of these substrates. Therefore, an extensive evaluation of available substrates would serve as a basis for the development of ZnO based devices and technologies. In this study, bulk ZnO single crystal substrates grown by different growth techniques have been characterised using synchrotron white beam X-ray topography and high resolution X-ray diffraction. The substrates exhibit a wide range of dislocation densities from as high as 10{sup 6} cm{sup -2} down to less than 1000 cm{sup -2} depending on the growth technique employed. The authors evaluation reveals that ZnO crystals grown by the hydrothermal technique possess the best structural quality with dislocation densities of 800-1000 cm{sup -2} and rocking curves with a full width half maximum of less than 12 arc seconds.

  13. Solution processable broadband transparent mixed metal oxide nanofilm optical coatings via substrate diffusion doping

    NASA Astrophysics Data System (ADS)

    Glynn, Colm; Aureau, Damien; Collins, Gillian; O'Hanlon, Sally; Etcheberry, Arnaud; O'Dwyer, Colm

    2015-11-01

    Devices composed of transparent materials, particularly those utilizing metal oxides, are of significant interest due to increased demand from industry for higher fidelity transparent thin film transistors, photovoltaics and a myriad of other optoelectronic devices and optics that require more cost-effective and simplified processing techniques for functional oxides and coatings. Here, we report a facile solution processed technique for the formation of a transparent thin film through an inter-diffusion process involving substrate dopant species at a range of low annealing temperatures compatible with processing conditions required by many state-of-the-art devices. The inter-diffusion process facilitates the movement of Si, Na and O species from the substrate into the as-deposited vanadium oxide thin film forming a composite fully transparent V0.0352O0.547Si0.4078Na0.01. Thin film X-ray diffraction and Raman scattering spectroscopy show the crystalline component of the structure to be α-NaVO3 within a glassy matrix. This optical coating exhibits high broadband transparency, exceeding 90-97% absolute transmission across the UV-to-NIR spectral range, while having low roughness and free of surface defects and pinholes. The production of transparent films for advanced optoelectronic devices, optical coatings, and low- or high-k oxides is important for planar or complex shaped optics or surfaces. It provides opportunities for doping metal oxides to ternary, quaternary or other mixed metal oxides on glass, encapsulants or other substrates that facilitate diffusional movement of dopant species.Devices composed of transparent materials, particularly those utilizing metal oxides, are of significant interest due to increased demand from industry for higher fidelity transparent thin film transistors, photovoltaics and a myriad of other optoelectronic devices and optics that require more cost-effective and simplified processing techniques for functional oxides and coatings

  14. Appetite-Enhancing Effects of Curry Oil.

    PubMed

    Ogawa, Kakuyou; Ito, Michiho

    2016-01-01

    Inhalation of scent compounds with phenylpropanoidal structures, such as trans-cinnamaldehyde, is expected to increase the appetite. The scent of curry powder is well known for its appetite-enhancing effect on humans. In this work, we show that the appetite of mice after inhalation of curry powder essential oil or benzylacetone showed a similar increase. The components of curry oil, trans-cinnamaldehyde, trans-anethole, and eugenol, each showed appetite-enhancing effects; therefore, these three scent compounds may be the active compounds in curry powder oil. PMID:27582336

  15. Anomalous charge trapping dynamics in cerium oxide grown on germanium substrate

    NASA Astrophysics Data System (ADS)

    Rahman, M. S.; Evangelou, E. K.; Dimoulas, A.; Mavrou, G.; Galata, S.

    2008-03-01

    We have observed charge trapping phenomena in thin films of cerium oxide on n-type germanium (Ge) substrate under constant voltage stress (CVS) condition. The measured shift of the flatband voltage of a high frequency C-V curve immediately after each CVS cycle, was utilized as a method to study the capture dynamics of both preexisting and stress induced oxide defects. At low stress electric field, it is the creation of new interface traps that dominates the trapping characteristics of the corresponding metal-oxide semiconductor capacitors. At higher stress electric field, negative charges are trapped on preexisting traps uniformly located in the bulk of the oxide. From data analysis, the capture cross section of the traps is estimated to be around 1×10-19cm2 which indicates neutral traps possibly related to H+ species and/or oxygen vacancies.

  16. Solution processable broadband transparent mixed metal oxide nanofilm optical coatings via substrate diffusion doping.

    PubMed

    Glynn, Colm; Aureau, Damien; Collins, Gillian; O'Hanlon, Sally; Etcheberry, Arnaud; O'Dwyer, Colm

    2015-12-21

    Devices composed of transparent materials, particularly those utilizing metal oxides, are of significant interest due to increased demand from industry for higher fidelity transparent thin film transistors, photovoltaics and a myriad of other optoelectronic devices and optics that require more cost-effective and simplified processing techniques for functional oxides and coatings. Here, we report a facile solution processed technique for the formation of a transparent thin film through an inter-diffusion process involving substrate dopant species at a range of low annealing temperatures compatible with processing conditions required by many state-of-the-art devices. The inter-diffusion process facilitates the movement of Si, Na and O species from the substrate into the as-deposited vanadium oxide thin film forming a composite fully transparent V0.0352O0.547Si0.4078Na0.01. Thin film X-ray diffraction and Raman scattering spectroscopy show the crystalline component of the structure to be α-NaVO3 within a glassy matrix. This optical coating exhibits high broadband transparency, exceeding 90-97% absolute transmission across the UV-to-NIR spectral range, while having low roughness and free of surface defects and pinholes. The production of transparent films for advanced optoelectronic devices, optical coatings, and low- or high-k oxides is important for planar or complex shaped optics or surfaces. It provides opportunities for doping metal oxides to ternary, quaternary or other mixed metal oxides on glass, encapsulants or other substrates that facilitate diffusional movement of dopant species. PMID:26575987

  17. Electrochromic properties of vanadium oxide thin films prepared by PSPT: Effect of substrate temperature

    NASA Astrophysics Data System (ADS)

    Patil, C. E.; Jadhav, P. R.; Tarwal, N. L.; Deshmukh, H. P.; Karanjakar, M. M.; Wali, A. A.; Patil, P. S.

    2013-06-01

    Electrochromic vanadium oxide (V2O5) thin films were deposited onto glass and fluorine doped tin oxide (FTO) coated glass substrates from methanolic vanadium chloride solution by pulsed spray pyrolysis technique (PSPT). The films were synthesized at different substrate temperatures ranging from 350°C-450°C with a temperature step of 50°C. The structural, morphological, optical and electrochromic properties of the synthesized films were investigated. The films were polycrystalline with tetragonal crystal structure. Scanning electron microscopy reveals compact morphology at high temperature. All films exhibited cathodic electrochromism in lithium containing electrolyte (0.5 M LiClO4 + Propylene Carbonate). Maximum coloration efficiency (CE) 15.16 cm2C-1, was observed for the films deposited at 350°C.

  18. Preparation of hydroxyapatite-containing titania coating on titanium substrate by micro-arc oxidation

    SciTech Connect

    Ni Jiahua; Shi Yulong Yan Fengying; Chen Jianzhi; Wang Lei

    2008-01-08

    Hydroxyapatite-containing titania coatings on titanium substrates were formed by micro-arc oxidation (MAO) in electrolyte containing calcium acetate monohydrate (CH{sub 3}COO){sub 2}Ca.H{sub 2}O) and sodium phosphate monobasic dihydrate (NaH{sub 2}PO{sub 4}.2H{sub 2}O) using a pulse power supply. Scanning electron microscopy (SEM) with Energy dispersive X-ray spectrometer (EDX) and X-ray diffraction (XRD) were employed to characterize the microstructure, elemental composition and phase components of the coatings. The coatings were rough and porous, without apparent interface to the titanium substrates. All the oxidized coatings contained Ca and P as well as Ti and O, and the porous coatings were made up of anatase, rutile and hydroxyapatite. Such MAO films are expected to have significant applications as artificial bone joints and dental implants.

  19. Dye-sensitized solar cells based on different nano-oxides on plastic PET substrate

    NASA Astrophysics Data System (ADS)

    Mikula, Milan; Gemeiner, Pavol; Beková, Zuzana; Dvonka, Vladimír; Búc, Dalibor

    2015-01-01

    Polyethylene-terephthalate (PET) foils and glass slides coated with thin conductive layers were used as substrates for TiO2 or ZnO based photoactive electrodes of dye-sensitized solar cells (DSSC) with organo-metallic Ru-dye, standard iodine electrolyte and Pt coated FTO/glass counterelectrode (CE). Different compositions of nanoparticle oxides in forms of alcohol pastes as well as the CE paste were applied onto the substrates by screen printing or by doctor blade techniques. Photocurrents and I-V loading characteristics were measured depending on the solar cell structure and preparation, including the oxide composition, electrode conductivity and the dye type. The influence of thin TiO2 blocking layer prepared by sol-gel technique is also discussed.

  20. Multiwell 14CO2-capture assay for evaluation of substrate oxidation rates of cells in culture.

    PubMed

    Collins, C L; Bode, B P; Souba, W W; Abcouwer, S F

    1998-05-01

    14CO2 capture is commonly used to evaluate the cellular oxidation rate of respiratory substrates. A modification of the established 14CO2-capture method was developed that enables the use of cells in adherent culture and easy analysis of multiple samples under different culture conditions. The use of commercially available culture and filter plates designed for use in a multiplate scintillation spectrophotometer enabled substrate oxidation rates to be evaluated for cells in a 24-well plate format without the need to dislodge the cells from the culture substrate as is required in traditional methods. Evaluation of radioactivity captured in potassium hydroxide-saturated filters was accomplished by adding scintillation fluid to the filter plate wells and counting. Alternatively, filters could be removed and placed in vials for evaluation in a conventional scintillation counter. This method was applied to the oxidation of 14C-glutamine by human breast cell lines and demonstrated concentration-dependent linear accumulation of captured counts. PMID:9591130

  1. Low-voltage indium gallium zinc oxide thin film transistors on paper substrates

    NASA Astrophysics Data System (ADS)

    Lim, Wantae; Douglas, E. A.; Norton, D. P.; Pearton, S. J.; Ren, F.; Heo, Young-Woo; Son, S. Y.; Yuh, J. H.

    2010-02-01

    We have fabricated bottom-gate amorphous (α-) indium-gallium-zinc-oxide (InGaZnO4) thin film transistors (TFTs) on both paper and glass substrates at low processing temperature (≤100 °C). As a water and solvent barrier layer, cyclotene (BCB 3022-35 from Dow Chemical) was spin-coated on the entire paper substrate. TFTs on the paper substrates exhibited saturation mobility (μsat) of 1.2 cm2 V-1 s-1, threshold voltage (VTH) of 1.9 V, subthreshold gate-voltage swing (S ) of 0.65 V decade-1, and drain current on-to-off ratio (ION/IOFF) of ˜104. These values were only slightly inferior to those obtained from devices on glass substrates (μsat˜2.1 cm2 V-1 s-1, VTH˜0 V, S ˜0.74 V decade-1, and ION/IOFF=105-106). The uneven surface of the paper sheet led to relatively poor contact resistance between source-drain electrodes and channel layer. The ability to achieve InGaZnO TFTs on cyclotene-coated paper substrates demonstrates the enormous potential for applications such as low-cost and large area electronics.

  2. [Characterization of peroxidase-catalyzed oxidation of chromogenic substrates by tetrazole and its 5-substituted derivatives].

    PubMed

    Karaseva, E I; Gaponik, P N; Metelitsa, D I

    2005-01-01

    Peroxidase-catalyzed oxidation of 2,2-azino-di(3-ethyl-benzthiazolydine-6-sulfonic acid) (ABTS) and 3,3',5,5'-tetramethylbenzidine (TMB) is activated by tetrazole and its 5-substituted derivatives--5-amino-(AmT), 5-methyl- (MeT), 5-phenyl- (PhT), and 5-CF3- (CF3-T) tetrazoles. In phosphate-citrate or phosphate buffer (pH 6.4 or 7.2; 20 degrees C), the activating effect of tetrazoles on TMB and ABTS oxidation decreased in the series AmT > MeT > T > PhT > CF3-T and T > AmT > MeT > PhT, respectively. The (coefficient) degree of activation (alpha), expressed in M(-1), determined for both substrates and all activators, depended on substrate type, buffer nature, and pH (it increased as pH increased from 6.4 to 7.2). For TMB oxidation, good correlation between lgalpha and the Hammet constants sigma(meta) for m-substituents in the benzene series NH2, CH3, C6H5, and CF3 was found. It is suggested that AmT, MeT, and T can be used as activators of peroxidase-catalyzed oxidation of TMB and ABTS, as well as in designing peroxidase-based biosensors. PMID:15859456

  3. Raman spectroscopy analysis of air grown oxide scale developed on pure zirconium substrate

    NASA Astrophysics Data System (ADS)

    Kurpaska, L.; Favergeon, J.; Lahoche, L.; El-Marssi, M.; Grosseau Poussard, J.-L.; Moulin, G.; Roelandt, J.-M.

    2015-11-01

    Using Raman spectroscopy technique, external and internal parts of zirconia oxide films developed at 500 °C and 600 °C on pure zirconium substrate under air at normal atmospheric pressure have been examined. Comparison of Raman peak positions of tetragonal and monoclinic zirconia phases, recorded during the oxide growth at elevated temperature, and after cooling at room temperature have been presented. Subsequently, Raman peak positions (or shifts) were interpreted in relation with the stress evolution in the growing zirconia scale, especially closed to the metal/oxide interface, where the influence of compressive stress in the oxide is the biggest. Reported results, for the first time show the presence of a continuous layer of tetragonal zirconia phase developed in the proximity of pure zirconium substrate. Based on the Raman peak positions we prove that this tetragonal layer is stabilized by the high compressive stress and sub-stoichiometry level. Presence of the tetragonal phase located in the outer part of the scale have been confirmed, yet its Raman characteristics suggest a stress-free tetragonal phase, therefore different type of stabilization mechanism. Presented study suggest that its stabilization could be related to the lattice defects introduced by highstoichiometry of zirconia or presence of heterovalent cations.

  4. Extracting mechanical properties of copper coatings on oxidized silicon substrates by nanoindentation

    NASA Astrophysics Data System (ADS)

    Moharrami, N.; Oila, A.; Bull, S. J.

    2014-08-01

    The thickness of the copper coatings that are used for the manufacture of conducting tracks in microelectronic devices are being aggressively scaled down and there is a need to monitor the mechanical response of metallization at a scale comparable to the material microstructure. When using indentation tests to assess the properties of thin films, the plastic zone dimensions are of a similar scale to the grain size. For the purposes of designs based on continuum mechanics approaches it is usually required that the grain size is much smaller than the deforming volume, which is not always observed in practice. Considerable differences between predicted and observed performance can be seen depending on the material tested and its grain size; the extent of oxidation of the copper after deposition is critical, as is that of its underlying silicon substrate. Whereas it is possible to make good measurements of metallization properties on stiff substrates such as silicon there are serious issues with the reliability of Young's modulus and hardness data from coatings on device quality wafers which may have been oxidized prior to use. The effects of grain size, shape and orientation on the mechanical response of metallic thin films used for semiconductor metallization on oxidized silicon are presented in this paper. The appropriate conditions for the successful use of continuum mechanics are discussed and the importance of considering the consequences of crystallographic anisotropy and oxidation on the selection of suitable design data is presented with regards to copper coatings.

  5. Biochemical Competition Makes Fatty-Acid β-Oxidation Vulnerable to Substrate Overload

    PubMed Central

    van Eunen, Karen; Simons, Sereh M. J.; Gerding, Albert; Bleeker, Aycha; den Besten, Gijs; Touw, Catharina M. L.; Houten, Sander M.; Groen, Bert K.; Krab, Klaas; Reijngoud, Dirk-Jan; Bakker, Barbara M.

    2013-01-01

    Fatty-acid metabolism plays a key role in acquired and inborn metabolic diseases. To obtain insight into the network dynamics of fatty-acid β-oxidation, we constructed a detailed computational model of the pathway and subjected it to a fat overload condition. The model contains reversible and saturable enzyme-kinetic equations and experimentally determined parameters for rat-liver enzymes. It was validated by adding palmitoyl CoA or palmitoyl carnitine to isolated rat-liver mitochondria: without refitting of measured parameters, the model correctly predicted the β-oxidation flux as well as the time profiles of most acyl-carnitine concentrations. Subsequently, we simulated the condition of obesity by increasing the palmitoyl-CoA concentration. At a high concentration of palmitoyl CoA the β-oxidation became overloaded: the flux dropped and metabolites accumulated. This behavior originated from the competition between acyl CoAs of different chain lengths for a set of acyl-CoA dehydrogenases with overlapping substrate specificity. This effectively induced competitive feedforward inhibition and thereby led to accumulation of CoA-ester intermediates and depletion of free CoA (CoASH). The mitochondrial [NAD+]/[NADH] ratio modulated the sensitivity to substrate overload, revealing a tight interplay between regulation of β-oxidation and mitochondrial respiration. PMID:23966849

  6. Metal Catalyst for Low-Temperature Growth of Controlled Zinc Oxide Nanowires on Arbitrary Substrates

    PubMed Central

    Kim, Baek Hyun; Kwon, Jae W.

    2014-01-01

    Zinc oxide nanowires generated by hydrothermal method present superior physical and chemical characteristics. Quality control of the growth has been very challenging and controlled growth is only achievable under very limited conditions using homogeneous seed layers with high temperature processes. Here we show the controlled ZnO nanowire growth on various organic and inorganic materials without the requirement of a homogeneous seed layer and a high temperature process. We also report the discovery of an important role of the electronegativity in the nanowire growth on arbitrary substrates. Using heterogeneous metal oxide interlayers with low-temperature hydrothermal methods, we demonstrate well-controlled ZnO nanowire arrays and single nanowires on flat or curved surfaces. A metal catalyst and heterogeneous metal oxide interlayers are found to determine lattice-match with ZnO and to largely influence the controlled alignment. These findings will contribute to the development of novel nanodevices using controlled nanowires. PMID:24625584

  7. Oxidation resistant high temperature thermal cycling resistant coatings on silicon-based substrates and process for the production thereof

    DOEpatents

    Sarin, Vinod K.

    1990-01-01

    An oxidation resistant, high temperature thermal cycling resistant coated ceramic article for ceramic heat engine applications. The substrate is a silicon-based material, i.e. a silicon nitride- or silicon carbide-based monolithic or composite material. The coating is a graded coating of at least two layers: an intermediate AlN or Al.sub.x N.sub.y O.sub.z layer and an aluminum oxide or zirconium oxide outer layer. The composition of the coating changes gradually from that of the substrate to that of the AlN or Al.sub.x N.sub.y O.sub.z layer and further to the composition of the aluminum oxide or zirconium oxide outer layer. Other layers may be deposited over the aluminum oxide layer. A CVD process for depositing the graded coating on the substrate is also disclosed.

  8. Oxidation resistant high temperature thermal cycling resistant coatings on silicon-based substrates and process for the production thereof

    DOEpatents

    Sarin, V.K.

    1990-08-21

    An oxidation resistant, high temperature thermal cycling resistant coated ceramic article for ceramic heat engine applications is disclosed. The substrate is a silicon-based material, i.e. a silicon nitride- or silicon carbide-based monolithic or composite material. The coating is a graded coating of at least two layers: an intermediate AlN or Al[sub x]N[sub y]O[sub z] layer and an aluminum oxide or zirconium oxide outer layer. The composition of the coating changes gradually from that of the substrate to that of the AlN or Al[sub x]N[sub y]O[sub z] layer and further to the composition of the aluminum oxide or zirconium oxide outer layer. Other layers may be deposited over the aluminum oxide layer. A CVD process for depositing the graded coating on the substrate is also disclosed.

  9. Enriched Iron(III)-Reducing Bacterial Communities are Shaped by Carbon Substrate and Iron Oxide Mineralogy

    PubMed Central

    Lentini, Christopher J.; Wankel, Scott D.; Hansel, Colleen M.

    2012-01-01

    Iron (Fe) oxides exist in a spectrum of structures in the environment, with ferrihydrite widely considered the most bioavailable phase. Yet, ferrihydrite is unstable and rapidly transforms to more crystalline Fe(III) oxides (e.g., goethite, hematite), which are poorly reduced by model dissimilatory Fe(III)-reducing microorganisms. This begs the question, what processes and microbial groups are responsible for reduction of crystalline Fe(III) oxides within sedimentary environments? Further, how do changes in Fe mineralogy shape oxide-hosted microbial populations? To address these questions, we conducted a large-scale cultivation effort using various Fe(III) oxides (ferrihydrite, goethite, hematite) and carbon substrates (glucose, lactate, acetate) along a dilution gradient to enrich for microbial populations capable of reducing Fe oxides spanning a wide range of crystallinities and reduction potentials. While carbon source was the most important variable shaping community composition within Fe(III)-reducing enrichments, both Fe oxide type and sediment dilution also had a substantial influence. For instance, with acetate as the carbon source, only ferrihydrite enrichments displayed a significant amount of Fe(III) reduction and the well-known dissimilatory metal reducer Geobacter sp. was the dominant organism enriched. In contrast, when glucose and lactate were provided, all three Fe oxides were reduced and reduction coincided with the presence of fermentative (e.g., Enterobacter spp.) and sulfate-reducing bacteria (e.g., Desulfovibrio spp.). Thus, changes in Fe oxide structure and resource availability may shift Fe(III)-reducing communities between dominantly metal-respiring to fermenting and/or sulfate-reducing organisms which are capable of reducing more recalcitrant Fe phases. These findings highlight the need for further targeted investigations into the composition and activity of speciation-directed metal-reducing populations within natural environments. PMID

  10. Influence of substrate preparation on the shaping of the topography of the surface of nanoceramic oxide layers

    NASA Astrophysics Data System (ADS)

    Bara, Marek; Kubica, Marek

    2014-02-01

    The paper discusses the shaping mechanism and changes occurring in the structure and topography of the surface of nanoceramic oxide layers during their formation. The paper presents the influence of substrate preparation on the surface topography of oxide layers. The layers were produced via hard anodizing on the EN AW-5251 aluminum alloy. The layers obtained were subjected to microscope examinations, image and chemical composition analyses, and stereometric examinations. Heredity of substrate properties in the topography of the surface of nanoceramic oxide layers formed as a result of electrochemical oxidation has been shown.

  11. Thermal oxidation-grown vanadium dioxide thin films on FTO (Fluorine-doped tin oxide) substrates

    NASA Astrophysics Data System (ADS)

    Tong, Guoxiang; Li, Yi; Wang, Feng; Huang, Yize; Fang, Baoying; Wang, Xiaohua; Zhu, Huiqun; Li, Liu; Shen, Yujian; Zheng, Qiuxin; Liang, Qian; Yan, Meng; Qin, Yuan; Ding, Jie

    2013-11-01

    By deposition of metallic vanadium on FTO substrate in Argon atmosphere at room temperature, the sample was then annealed in furnace for 2 h at the temperature of 410 °C in air ambient. (1 1 0) -orientated vanadium dioxide films were prepared on the FTO surface. A maximum transmittance of ˜40% happened at 900-1250 nm region at room temperature. The change of optical transmittance at this region was ˜25% between semiconducting and metallic states. In particular, vanadium dioxide thin films on FTO exhibit semiconductor-metal phase transition at ˜51 °C, the width of the hysteresis loop is ˜8 °C.

  12. Stoichiometry of Proton Translocation Coupled to Substrate Oxidation in Plant Mitochondria

    PubMed Central

    Moreau, François; de Virville, Jacques Davy

    1985-01-01

    The proton translocation coupled to the electron flux from succinate, exogenous NADH, and NAD+-linked substrates (malate and isocitrate) to cytochrome c and to oxygen was studied in purified potato (Solanum tuberosum) mitochondria using oxygen and ferricyanide pulse techniques. In the presence of valinomycin plus K+ (used as a charge compensating cation), optimum values of H+/2 e− were obtained when low amounts of electron acceptors (oxygen or ferricyanide) were added to the mitochondria (1-2 nanogram [2 e−] equivalents per milligram protein). The stoichiometry of proton translocation to electron flux was unaffected in the presence of N-ethylmaleimide, an inhibitor of the Pi/H+ symport. With succinate as substrate, H+/2 e− ratios were 4.0 ± 0.2 and 3.7 ± 0.3 with oxygen and ferricyanide as electron acceptors, respectively. With exogenous NADH, H+/2e− ratios were 4.1 ± 0.9 and 3.4 ± 0.2, respectively. The proton translocation coupled to the oxidation of NAD+-linked substrates (malate, isocitrate) was dependent upon the presence of adenylates (ADP, AMP, or ATP). For malate (+ glutamate) oxidation the observed H+/2 e− ratios were increased from 3.6 ± 2.2 to 6.5 ± 0.5 in the presence of 20 micromolar ADP. PMID:16663992

  13. Gaseous Oxidized Mercury Flux from Substrates Associated with Industrial Scale Gold Mining in Nevada, USA

    NASA Astrophysics Data System (ADS)

    Miller, M. B.

    2015-12-01

    Gaseous elemental and oxidized mercury (Hg) fluxes were measured in a laboratory setting from substrate materials derived from industrial-scale open pit gold mining operations in Nevada, USA. Mercury is present in these substrates at a range of concentrations (10 - 40000 ng g-1), predominantly of local geogenic origin in association with the mineralized gold ores, but altered and redistributed to a varying degree by subsequent ore extraction and processing operations, including deposition of Hg recently emitted to the atmosphere from large point sources on the mines. Waste rock, heap leach, and tailings material usually comprise the most extensive and Hg emission relevant substrate surfaces. All three of these material types were collected from active Nevada mine sites in 2010 for previous research, and have since been stored undisturbed at the University of Nevada, Reno. Gaseous elemental Hg (GEM) flux was previously measured from these materials under a variety of conditions, and was re-measured in this study, using Teflon® flux chambers and Tekran® 2537A automated ambient air analyzers. GEM flux from dry undisturbed materials was comparable between the two measurement periods. Gaseous oxidized Hg (GOM) flux from these materials was quantified using an active filter sampling method that consisted of polysulfone cation-exchange membranes deployed in conjunction with the GEM flux apparatus. Initial measurements conducted within greenhouse laboratory space indicate that in dry conditions GOM is deposited to relatively low Hg cap and leach materials, but may be emitted from the much higher Hg concentration tailings material.

  14. Spinel-structured metal oxide on a substrate and method of making same by molecular beam epitaxy

    DOEpatents

    Chambers, Scott A.

    2006-02-21

    A method of making a spinel-structured metal oxide on a substrate by molecular beam epitaxy, comprising the step of supplying activated oxygen, a first metal atom flux, and at least one other metal atom flux to the surface of the substrate, wherein the metal atom fluxes are individually controlled at the substrate so as to grow the spinel-structured metal oxide on the substrate and the metal oxide is substantially in a thermodynamically stable state during the growth of the metal oxide. A particular embodiment of the present invention encompasses a method of making a spinel-structured binary ferrite, including Co ferrite, without the need of a post-growth anneal to obtain the desired equilibrium state.

  15. (110)-oriented indium tin oxide films grown on m- and r-plane sapphire substrates

    NASA Astrophysics Data System (ADS)

    Chern, Ming-Yau; Lu, Tso-Wen; Xu, Wei-Lun

    2015-04-01

    Indium tin oxide (ITO) thin films have been deposited by pulsed laser deposition on m-plane (100) and r-plane (012) sapphire substrates. For both substrates, the films were grown with their [110] direction perpendicular to the substrate planes under the conditions of high growth temperature and high oxygen pressure. Their in-plane epitaxial relations with the substrates were identified to be ITO[001] ∥ Al2O3[020] and \\text{ITO}[1\\bar{1}0]\\parallel \\text{Al}2\\text{O}3[001] for the m-plane substrate. For the r-plane substrate, two types of lattice matching were observed: one being \\text{ITO}[001]\\parallel \\text{Al}2\\text{O}3[2,1, - 1/2] and \\text{ITO}[1\\bar{1}0]\\parallel \\text{Al}2\\text{O}3[4/3, - 4/3,2/3], the other being \\text{ITO}[001]\\parallel \\text{Al}2\\text{O}3[1, - 1,1/2] and \\text{ITO}[1\\bar{1}0]/\\text{Al}2\\text{O}3[8/3,4/3, - 2/3]. The electrical properties were measured by the Hall effect and van der Pauw methods at room temperature. All of the samples have low electrical resistivity on the order of 3.0 × 10-4 Ω cm, high carrier concentration of about 2.5 × 1020 cm-3, and mobility ranging from 70 to 90 cm2 V-1 s-1.

  16. Influence of Substrate Complexity on the Diastereoselective Formation of Spiroiminodihydantoin and Guanidinohydantoin from Chromate Oxidation

    PubMed Central

    Gremaud, Julia N.; Martin, Brooke D.; Sugden, Kent D.

    2009-01-01

    Chromate is a human carcinogen with a poorly defined mechanism of DNA damage. In vitro and prokaryotic studies have shown that DNA damage may occur via the formation of the hydantoin lesions guanidinohydantoin (Gh) and spiroiminodihydantoin (Sp) from further oxidation of 8-oxo-7,8-dihydroguanine (8oxoG). The unusual structure of these lesions coupled with their enhanced mutagenicity make them attractive for study with regard to their role in chromate-induced cancer. We have studied the formation of Gh versus Sp and their associated diastereomers following oxidation by model Cr(V) complexes and from in situ chromate reduction by ascorbate and glutathione. Identification of the two optically assigned diastereomers of Sp (R-Sp, S-Sp) as well as the two diastereomers of Gh, (Gh1 and Gh2; not yet optically assigned) were carried out using increasingly sterically hindered substrates (nucleoside → ssDNA → dsDNA). Lesion formation and diastereomeric preference was found to be highly oxidant- and substrate-dependent. The Ir(IV) positive control showed a shift from near equal levels of Gh and Sp, and near equal levels of all four diastereomers in the nucleoside, to all Gh formation in dsDNA, with a 5-fold enhancement in Gh2 over Gh1. The two model Cr(V) complexes used in this study, Cr(V)-salen and Cr(V)-ehba, showed opposite trends going from nucleoside to dsDNA with Cr(V)-salen giving enhanced Sp formation (with mainly R-Sp formed) and the Cr(V)-ehba having an oxidation profile nearly identical to that of Ir(IV). The two chromate reduction systems, Cr6+/ascorbate and Cr6+/glutathione, designed to model the intracellular reduction of chromate, showed lower levels of oxidation in all substrates. Notable in this group was the shift in the formation of the lesions to essentially all Sp for the Cr6+/ascorbate system with the most sterically hindered substrate, dsDNA. These results, when coupled with the known diastereomeric preference for excision of hydantoin lesions by

  17. Oxidization without substrate unfolding triggers proteolysis of the peroxide-sensor, PerR.

    PubMed

    Ahn, Bo-Eun; Baker, Tania A

    2016-01-01

    Peroxide operon regulator (PerR) is a broadly conserved hydrogen peroxide sensor in bacteria, and oxidation of PerR at its regulatory metal-binding site is considered irreversible. Here, we tested whether this oxidation specifically targets PerR for proteolysis. We find that oxidizing conditions stimulate PerR degradation in vivo, and LonA is the principal AAA+ (ATPases associated with diverse cellular activities) protease that degrades PerR. Degradation of PerR by LonA is recapitulated in vitro, and biochemical dissection of this degradation reveals that the presence of regulatory metal and PerR-binding DNA dramatically extends the half-life of the protein. We identified a LonA-recognition site critical for oxidation-controlled PerR turnover. Key residues for LonA-interaction are exposed to solvent in PerR lacking metal, but are buried in the metal-bound form. Furthermore, one residue critical for Lon recognition is also essential for specific DNA-binding by PerR, thus explaining how both the metal and DNA ligands prevent PerR degradation. This ligand-controlled allosteric mechanism for protease recognition provides a compelling explanation for how the oxidation-induced conformational change in PerR triggers degradation. Interestingly, the critical residues recognized by LonA and exposed by oxidation do not function as a degron, because they are not sufficient to convert a nonsubstrate protein into a LonA substrate. Rather, these residues are a conformation-discriminator sequence, which must work together with other residues in PerR to evoke efficient degradation. This mechanism provides a useful example of how other proteins with only mild or localized oxidative damage can be targeted for degradation without the need for extensive oxidation-dependent protein denaturation. PMID:26677871

  18. The crystallinity and mechanical properties of indium tin oxide coatings on polymer substrates

    SciTech Connect

    Kim, Eun-Hye; Yang, Chan-Woo; Park, Jin-Woo

    2011-02-15

    We present the relationship between the microstructure and mechanical strength of indium tin oxide (ITO) on flexible substrates. With varying thickness (h{sub f}), ITO is deposited on polyethylene terephthalate (PET) by dc magnetron sputtering. The microstructure of ITO is controlled by substrate surface conditions and sputtering parameters. The maximum substrate temperature during deposition is limited to 80 deg. C due to the low glass transition temperature (T{sub g}) of PET. The crystallinity and surface roughness (R{sub rms}) are analyzed by high resolution x-ray diffraction, high resolution transmission electron microscopy, and AFM. The crack resistance of ITO is evaluated by uniaxial tension test. The experimental results reveal that, at a fixed h{sub f}, the degree and quality of crystallinity of ITO are highly improved by increasing sputtering power and the substrate temperature. As the crystallinity is improved, the ratio of preferred growth orientations of (222) to (400) is increased and the degree of peak shifts to lower 2{theta} is decreased. They indicate that the crystallinity is improved as the lattice damage is reduced and film density is increased. The tension test results confirm that, up to a certain h{sub f}, the strength of ITO can be significantly enhanced by improving the microstructures.

  19. The crystallinity and mechanical properties of indium tin oxide coatings on polymer substrates

    NASA Astrophysics Data System (ADS)

    Kim, Eun-Hye; Yang, Chan-Woo; Park, Jin-Woo

    2011-02-01

    We present the relationship between the microstructure and mechanical strength of indium tin oxide (ITO) on flexible substrates. With varying thickness (hf), ITO is deposited on polyethylene terephthalate (PET) by dc magnetron sputtering. The microstructure of ITO is controlled by substrate surface conditions and sputtering parameters. The maximum substrate temperature during deposition is limited to 80 °C due to the low glass transition temperature (Tg) of PET. The crystallinity and surface roughness (Rrms) are analyzed by high resolution x-ray diffraction, high resolution transmission electron microscopy, and AFM. The crack resistance of ITO is evaluated by uniaxial tension test. The experimental results reveal that, at a fixed hf, the degree and quality of crystallinity of ITO are highly improved by increasing sputtering power and the substrate temperature. As the crystallinity is improved, the ratio of preferred growth orientations of (222) to (400) is increased and the degree of peak shifts to lower 2θ is decreased. They indicate that the crystallinity is improved as the lattice damage is reduced and film density is increased. The tension test results confirm that, up to a certain hf, the strength of ITO can be significantly enhanced by improving the microstructures.

  20. Stretchable metal oxide thin film transistors on engineered substrate for electronic skin applications.

    PubMed

    Romeo, Alessia; Lacour, Stphanie P

    2015-08-01

    Electronic skins aim at providing distributed sensing and computation in a large-area and elastic membrane. Control and addressing of high-density soft sensors will be achieved when thin film transistor matrices are also integrated in the soft carrier substrate. Here, we report on the design, manufacturing and characterization of metal oxide thin film transistors on these stretchable substrates. The TFTs are integrated onto an engineered silicone substrate with embedded strain relief to protect the devices from catastrophic cracking. The TFT stack is composed of an amorphous In-Ga-Zn-O active layer, a hybrid AlxOy/Parylene dielectric film, gold electrodes and interconnects. All layers are prepared and patterned with planar, low temperature and dry processing. We demonstrate the interconnected IGZO TFTs sustain applied tensile strain up to 20% without electrical degradation and mechanical fracture. Active devices are critical for distributed sensing. The compatibility of IGZO TFTs with soft and biocompatible substrates is an encouraging step towards wearable electronic skins. PMID:26738152

  1. Influence of organic substrates on the kinetics of bacterial As(III) oxidation

    NASA Astrophysics Data System (ADS)

    Lescure, T.; Joulian, C.; Bauda, P.; Hénault, C.; Battaglia-Brunet, F.

    2012-04-01

    Soil microflora plays a major role on the behavior of metals and metalloids. Arsenic speciation, in particular, is related to the activity of bacteria able to oxidize, reduce or methylate this element, and determines mobility, bioavailability and toxicity of As. Arsenite (AsIII) is more toxic and more mobile than arsenate (AsV). Bacterial As(III)-oxidation tends to reduce the toxicity of arsenic in soils and the risk of transfer toward underlying aquifers, that would affect the quality of water resources. Previous results suggest that organic matter may affect kinetics or efficiency of bacterial As(III)-oxidation in presence of oxygen, thus in conventional physico-chemical conditions of a surface soil. Different hypothesis can be proposed to explain the influence of organic matter on As(III) oxidation. Arsenic is a potential energy source for bacteria. The presence of easily biodegradable organic matter may inhibit the As(III) oxidation process because bacteria would first metabolize these more energetic substrates. A second hypothesis would be that, in presence of organic matter, the Ars system involved in bacterial resistance to arsenic would be more active and would compete with the Aio system of arsenite oxidation, decreasing the global As(III) oxidation rate. In addition, organic matter influences the solubility of iron oxides which often act as the main pitfalls of arsenic in soils. The concentration and nature of organic matter could therefore have a significant influence on the bioavailability of arsenic and hence on its environmental impact. The influence of organic matter on biological As(III) oxidation has not yet been determined in natural soils. In this context, soil amendment with organic matter during operations of phytostabilization or, considering diffuse pollutions, through agricultural practices, may affect the mobility and bio-availability of the toxic metalloid. The objective of the present project is to quantify the influence of organic matter

  2. Polypyrrole Coated Cellulosic Substrate Modified by Copper Oxide as Electrode for Nitrate Electroreduction

    NASA Astrophysics Data System (ADS)

    Hamam, A.; Oukil, D.; Dib, A.; Hammache, H.; Makhloufi, L.; Saidani, B.

    2015-08-01

    The aim of this work is to synthesize polypyrrole (PPy) films on nonconducting cellulosic substrate and modified by copper oxide particles for use in the nitrate electroreduction process. Firstly, the chemical polymerization of polypyrrole onto cellulosic substrate is conducted by using FeCl3 as an oxidant and pyrrole as monomer. The thickness and topography of the different PPy films obtained were estimated using a profilometer apparatus. The electrochemical reactivity of the obtained electrodes was tested by voltamperometry technique and electrochemical impedance spectroscopy. Secondly, the modification of the PPy film surface by incorporation of copper oxide particles is conducted by applying a galvanostatic procedure from a CuCl2 solution. The SEM, EDX and XRD analysis showed the presence of CuO particles in the polymer films with dimensions less than 50 nm. From cyclic voltamperometry experiments, the composite activity for the nitrate electroreduction reaction was evaluated and the peak of nitrate reduction is found to vary linearly with initial nitrate concentration.

  3. Fabrication of a substrate-independent aluminum oxide-GaAs distributed Bragg reflector

    SciTech Connect

    Wohlert, D.E.; Lin, H.C.; Chang, K.L.; Pickrell, G.W. Jr.; Epple, J.H.; Hsieh, K.C.; Cheng, K.Y. )

    1999-09-01

    We propose a method for forming a top distributed Bragg reflector (DBR) during very-low temperature (VLT) molecular-beam epitaxy (MBE) growth that is independent of the substrate being used. By varying the arsenic overpressure during VLT MBE, it was determined by Auger electron spectroscopy and cross-section transmission electron microscopy that alternating layers of polycrystalline GaAs and amorphous (Al,As) can be deposited. Because these layers are not single crystal, they can be grown on any host lattice. After lateral wet oxidation, the polycrystalline GaAs does not undergo any significant changes; whereas the amorphous (Al,As) becomes an amorphous aluminum oxide. An index step of [Delta]n=1.88 is realized between these two layers which makes it possible to fabricate a high efficiency DBR with very few polycrystal-GaAs/amorphous-Al-oxide pairs on GaAs-, GaP-, or InP-based materials. Using reflectivity measurements, we demonstrate a five pair GaAs/AlAs-based DBR grown on an InP substrate that reflects wavelengths between 1.4 and 2.3 [mu]m up to 95[percent]. [copyright] [ital 1999 American Institute of Physics.

  4. Hydrogen peroxide generation by higher plant mitochondria oxidizing complex I or complex II substrates.

    PubMed

    Braidot, E; Petrussa, E; Vianello, A; Macri, F

    1999-05-28

    The generation of H2O2 by isolated pea stem mitochondria, oxidizing either malate plus glutamate or succinate, was examined. The level of H2O2 was almost one order of magnitude higher when mitochondria were energized by succinate. The succinate-dependent H2O2 formation was abolished by malonate, but unaffected by rotenone. The lack of effect of the latter suggests that pea mitochondria were working with a proton motive force below the threshold value required for reverse electron transfer. The activation by pyruvate of the alternative oxidase was reflected in an inhibition of H2O2 formation. This effect was stronger when pea mitochondria oxidized malate plus glutamate. Succinate-dependent H2O2 formation was ca. four times lower in Arum sp. mitochondria (known to have a high alternative oxidase) than in pea mitochondria. An uncoupler (FCCP) completely prevented succinate-dependent H2O2 generation, while it only partially (40-50%) inhibited that linked to malate plus glutamate. ADP plus inorganic phosphate (transition from state 4 to state 3) also inhibited the succinate-dependent H2O2 formation. Conversely, that dependent on malate plus glutamate oxidation was unaffected by low and stimulated by high concentrations of ADP. These results show that the main bulk of H2O2 is formed during substrate oxidation at the level of complex II and that this generation may be prevented by either dissipation of the electrochemical proton gradient (uncoupling and transition state 4-state 3), or preventing its formation (alternative oxidase). Conversely, H2O2 production, dependent on oxidation of complex I substrate, is mainly lowered by the activation of the alternative oxidase. PMID:10371218

  5. Cerium oxide layers on the Cu(1 1 1) surface: Substrate-mediated redox properties

    NASA Astrophysics Data System (ADS)

    Wrobel, R.; Suchorski, Y.; Becker, S.; Weiss, H.

    Ceria submonolayers consisting of nanosized 2D islands on a Cu(1 1 1) surface have been prepared by oxidation of the nucleating Ce submonolayer (0.7 ML) and characterized using XPS and STM. The reducibility of the resulting well-defined CeO 2-x/Cu(1 1 1) model system of the "inverse supported catalyst" type was studied by XPS using CO as reducing agent. In order to investigate the contribution of the substrate in the redox process, the properties of a ceria submonolayer (0.7 ML) on Cu(1 1 1), of an optically dense layer of ceria (1.5 ML) on Cu(1 1 1) and of a ceria submonolayer (0.7 ML) on Pt(1 1 1) have been compared. The direct comparison reveals the (metal substrate mediated) spillover mechanism of the ceria reduction by CO in the present CeO 2-x/Me fcc(1 1 1) model systems.

  6. Electrophoretic deposition of graphene oxide reinforced chitosan-hydroxyapatite nanocomposite coatings on Ti substrate.

    PubMed

    Shi, Y Y; Li, M; Liu, Q; Jia, Z J; Xu, X C; Cheng, Y; Zheng, Y F

    2016-03-01

    Electrophoretic deposition (EPD) is a facile and feasible technique to prepare functional nanocomposite coatings for application in orthopedic-related implants. In this work, a ternary graphene oxide-chitosan-hydroxyapatite (GO-CS-HA) composite coating on Ti substrate was successfully fabricated by EPD. Coating microstructure and morphologies were investigated by scanning electron microscopy, contact angle test, Raman spectroscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis. It was found GO-CS surface were uniformly decorated by HA nanoparticles. The potentiodynamic polarization test in simulated body fluid indicated that the GO-CS-HA coatings could provide effective protection of Ti substrate from corrosion. This ternary composite coating also exhibited good biocompatibility during incubation with MG63 cells. In addition, the nanocomposite coatings could decrease the attachment of Staphylococcus aureus. PMID:26758895

  7. Tailored surfaces of perovskite oxide substrates for conducted growth of thin films.

    PubMed

    Sánchez, Florencio; Ocal, Carmen; Fontcuberta, Josep

    2014-04-01

    Oxide electronics relies on the availability of epitaxial oxide thin films. The extreme flexibility of the chemical composition of ABO3 perovskites and the broad spectrum of properties they cover, inspire the creativity of scientists and place perovskites in the lead of functional materials for advanced technologies. Moreover, emerging properties are being discovered at interfaces between distinct perovskites that could not be anticipated on the basis of those of the adjacent epitaxial layers. All dreamed new prospects require the use of suitable substrates for epitaxial growth. Perovskite single crystals are the workhorses of this activity and understanding and controlling their surface properties have become critical. In this tutorial review we will chiefly focus on the impact of the morphology and composition of the surface of ABO3 perovskite substrates on the growth mechanisms and properties of thin films epitaxially grown on them. As SrTiO3 is the most popular substrate, we will mostly concentrate on describing the current understanding and achievements for it. Illustrative examples of other perovskite substrates (LaAlO3, LSAT and DyScO3) will be also included. We will show that distinct chemical terminations can exist on the surfaces used for growth and we will review methods employed either to select the most appropriate one for specific growth to allow, for instance, tailoring the ultimate outmost epilayer, or to induce self-ordering to engineer long-range nanoscale patterns of chemical terminations. We will demonstrate the capacity of this knowledge by the growth of low-dimensional organic and inorganic structures. PMID:24553667

  8. Electrical and optical properties of pyrolytically electrostatic sprayed fluorine-doped tin-oxide: Dependence on substrate-temperature and substrate-nozzle distance

    NASA Astrophysics Data System (ADS)

    Zaouk, D.; Zaatar, Y.; Khoury, A.; Llinares, C.; Charles, J.-P.; Bechara, J.

    2000-05-01

    Tin-oxide (SnO2) thin films were prepared by a modified spray technique called electrostatic spray pyrolysis. Their electrical and optical properties dependence on fluorine concentration, substrate temperature Ts, and the substrate-nozzle distance Dsn was studied. Dsn and Ts seem to be interrelated for the optimization of good quality fluorine-doped SnO2 films. Films of about 9×10-4 Ω cm resistivity and high visible 85% transparency were obtained for a substrate temperature of 550 °C, a 6 cm substrate nozzle distance, and 80% of hydrofluorhydric acid HF in the starting solution. These data are discussed in light of the kinetics reaction.

  9. Elemental Metals or Oxides Distributed on a Carbon Substrate or Self-Supported and the Manufacturing Process Using Graphite Oxide as Template

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Chen (Inventor)

    1999-01-01

    A process for providing elemental metals or metal oxides distributed on a carbon substrate or self-supported utilizing graphite oxide as a percursor. The graphite oxide is exposed to one or more metal chlorides to form an intermediary product comprising carbon, metal, chloride, and oxygen. This intermediary product can be further processed by direct exposure to carbonate solutions to form a second intermediary product comprising carbon, metal carbonate, and oxygen. Either intermediary product may be further processed: a) in air to produce metal oxide; b) in an inert environment to produce metal oxide on carbon substrate; c) in a reducing environment to produce elemental metal distributed on carbon substrate. The product generally takes the shape of the carbon precursor.

  10. Elemental Metals or Oxides Distributed on a Carbon Substrate or Self-Supported and the Manufacturing Process Using Graphite Oxide as Template

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Cheh (Inventor)

    1999-01-01

    A process for providing elemental metals or metal oxides distributed on a carbon substrate or self-supported utilizing graphite oxide as a precursor. The graphite oxide is exposed to one or more metal chlorides to form an intermediary product comprising carbon, metal, chloride, and oxygen. This intermediary product can be further processed by direct exposure to carbonate-solutions to form a second intermediary product comprising carbon, metal carbonate, and oxygen. Either intermediary product may be further processed: a) in air to produce metal oxide; b) in an inert environment to produce metal oxide on carbon substrate; c) in a reducing environment to produce elemental metal distributed on carbon substrate. The product generally takes the shape of the carbon precursor.

  11. Substrate oxidation capacity in rodent skeletal muscle: effects of exposure to zero gravity

    NASA Technical Reports Server (NTRS)

    Baldwin, K. M.; Herrick, R. E.; McCue, S. A.

    1993-01-01

    A study was conducted, as part of the integrated National Aeronautics and Space Administration Space Life Sciences 1 mission flown in June of 1991, to ascertain the effects of 9 days of exposure to zero gravity on the capacity of rodent skeletal muscle fiber types to oxidize either [14C]pyruvate or [14C]palmitate under state 3 metabolic conditions, i.e., nonlimiting amounts of substrate and cofactors. In addition, activity levels of marker enzymes of the tricarboxylic acid cycle, malate shuttle, and beta-oxidation were measured. Results showed that significant differences in muscle weight occurred in both the predominantly slow vastus intermedius and predominantly fast vastus lateralis of flight vs. control groups (P < 0.05). Total protein content of the muscle samples was similar between groups. Both pyruvate oxidation capacity and the marker oxidative enzymes were not altered in the flight relative to control animals. However, the capacity to oxidize long-chain fatty acids was significantly reduced by 37% in both the high- and low-oxidative regions of the vastus muscle (P < 0.05). Although these findings of a selective reduction in fatty acid oxidation capacity in response to spaceflight are surprising, they are consistent with previous findings showing 1) an increased capacity to take up glucose and upregulate glucose transporter proteins and 2) a marked accumulation of triglycerides in the skeletal muscles of rats subjected to states of unloading. Thus, skeletal muscle of animals exposed to non-weight-bearing environments undergo subcellular transformations that may preferentially bias energy utilization to carbohydrates.

  12. Crystal Structure of Oxidative Stress Sensor Keap1 in Complex with Selective Autophagy Substrate p62

    NASA Astrophysics Data System (ADS)

    Kurokawa, Hirofumi

    Keap1, an adaptor protein of cullin-RING ubiquitin ligase complex, represses cytoprotective transcription factor Nrf2 in an oxidative stress-dependent manner. The accumulation of selective autophagy substrate p62 also activates Nrf2 target genes, but the detailed mechanism has not been elucidated. Crystal structure of Keap1-p62 complex revealed the structural basis for the Nrf2 activation in which Keap1 is inactivated by p62. The accumulation of p62 is observed in hepatocellular carcinoma. The activation of Nrf2 target genes, including detoxifying enzymes and efflux transporters, by p62 may protect the cancer cells from anti-cancer drugs.

  13. Transparent conductive indium oxide film deposited on low temperature substrates by activated reactive evaporation.

    PubMed

    Marcovitch, O; Klein, Z; Lubezky, I

    1989-07-15

    High quality conductive coatings for the visible region were prepared on low temperature glass substrates. The conductive layer was an indium oxide film deposited by the activated reactive evaporation technique using a glow discharge hollow cathode ion gun. An antireflective layer of MgF(2) was deposited over the conductive layer. The average transmission in the visible region of the coated glass with sheet resistance of < 15 Omega/sq was greater than 90%. The coating was durable and passed a series of environmental tests according to MIL-C-675C. PMID:20555600

  14. Graphdiyne oxides as excellent substrate for electroless deposition of Pd clusters with high catalytic activity.

    PubMed

    Qi, Hetong; Yu, Ping; Wang, Yuexiang; Han, Guangchao; Liu, Huibiao; Yi, Yuanping; Li, Yuliang; Mao, Lanqun

    2015-04-29

    Graphdiyne (GDY), a novel kind of two-dimensional carbon allotrope consisting of sp- and sp(2)-hybridized carbon atoms, is found to be able to serve as the reducing agent and stabilizer for electroless deposition of highly dispersed Pd nanoparticles owing to its low reduction potential and highly conjugated electronic structure. Furthermore, we observe that graphdiyne oxide (GDYO), the oxidation form of GDY, can be used as an even excellent substrate for electroless deposition of ultrafine Pd clusters to form Pd/GDYO nanocomposite that exhibits a high catalytic performance toward the reduction of 4-nitrophenol. The high catalytic performance is considered to benefit from the rational design and electroless deposition of active metal catalysts with GDYO as the support. PMID:25871853

  15. Effects of substrates on N2O emissions in an anaerobic ammonium oxidation (anammox) reactor.

    PubMed

    Jin, Yue; Wang, Dunqiu; Zhang, Wenjie

    2016-01-01

    N2O emission in the anaerobic ammonium oxidation (anammox) process is of growing concern. In this study, effects of substrate concentrations on N2O emissions were investigated in an anammox reactor. Extremely high N2O emissions of 1.67 % were led by high NH4-N concentrations. Results showed that N2O emissions have a positive correlation with NH4-N concentrations in the anammox reactor. Reducing NH4-N concentrations by recycling pump resulted in decreasing N2O emissions. In addition, further studies were performed to identify a key biological process that is contributed to N2O emissions from the anammox reactor. Based on the results obtained, Nitrosomonas, which can oxidize ammonia to nitrite, was deemed as the main sources of N2O emissions. PMID:27376009

  16. Alkylamine-Dependent Amino-Acid Oxidation by Lysine Monooxygenase—Fragmented Substrate of Oxygenase

    PubMed Central

    Yamamoto, Shozo; Yamauchi, Takashi; Hayaishi, Osamu

    1972-01-01

    Lysine monooxygenase catalyzes the oxygenative decarboxylation of L-lysine and produces a corresponding acid amide. L-Alanine was inactive as substrate. However, when propylamine was present, oxidation, but not oxygenation, of alanine was demonstrated with the oxygenase. Alanine was converted to pyruvate, with the liberation of ammonia and hydrogen peroxide, but propylamine remained unchanged. Other α-monoamino acids were also oxidized in the presence of alkylamines with various carbon chain lengths. The highest oxidase activity was observed when the total chain length of both amino acid and amine was nearly identical with that of lysine. Available evidence indicates that the amine-dependent amino-acid oxidase activity is associated with the lysine oxygenase activity. PMID:4509334

  17. Cytochrome P450-like substrate oxidation catalyzed by cytochrome c and immobilized cytochrome c.

    PubMed

    Akasaka, R; Mashino, T; Hirobe, M

    1993-03-01

    Cytochrome c (cyt.c) was shown to catalyze cytochrome P450 (P450)-like oxidative reactions, such as N-, and O-demethylation, S-oxidation, and epoxidation of olefins. A more detailed examination showed that (i) N-methylcarbazole and thioanisole oxidation with H2(18)O2 catalyzed by cyt.c resulted in introduction of 18O into the product, and (ii) during the epoxidation of cis-stilbene catalyzed by cyt.c, the stereochemistry of the substrate was retained and 18O was introduced when H2(18)O2 was used as an oxidant. These results show that cyt.c catalyzed N-demethylation, S-oxidation, and epoxidation in the same manner as P450. To utilize these P450-like reactivities effectively, cyt.c was immobilized on poly-gamma-methyl-L-glutamate. Up to 99% of the cyt.c used was immobilized. This immobilized cyt.c catalyzed N-demethylation, S-oxidation, and epoxidation in the same manner as both P450 and free cyt.c, and the activities of these reactions were increased by the immobilization. In N-demethylation of N,N-dimethylaniline with cumene hydroperoxide (CHP) catalyzed by cyt.c, the Vmax for CHP was increased by 4.4-fold by the immobilization of the enzyme, while the Km remained unchanged. Since P450 is involved in the metabolism of many xenobiotics, the above results suggest that immobilized cyt.c may be useful in drug metabolism research. PMID:7681661

  18. Latina mothers' influences on child appetite regulation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Parents influence child weight through interactions that shape the development of child eating behaviors. In this study we examined the association between maternal autonomy promoting serving practices and child appetite regulation. We predicted that maternal autonomy promoting serving practices wou...

  19. Reduced Graphene Oxide Thin Film on Conductive Substrates by Bipolar Electrochemistry

    NASA Astrophysics Data System (ADS)

    Anis, Allagui; Mohammad, Ali Abdelkareem; Hussain, Alawadhi; Ahmed, S. Elwakil

    2016-02-01

    Recent years have shown an increased interest in developing manufacturing processes for graphene and its derivatives that consider the environmental impact and large scale cost-effectiveness. However, today’s most commonly used synthesis routes still suffer from their excessive use of harsh chemicals and/or the complexity and financial cost of the process. Furthermore, the subsequent transfer of the material onto a substrate makes the overall process even more intricate and time-consuming. Here we describe a single-step, single-cell preparation procedure of metal-supported reduced graphene oxide (rGO) using the principle of bipolar electrochemistry of graphite in deionized water. Under the effect of an electric field between two stainless steel feeder electrodes, grapheme layers at the anodic pole of the wireless graphite were oxidized into colloidal dispersion of GO, which migrated electrophoretically towards the anodic side of the cell, and deposited in the form of rGO (d(002) = 0.395 nm) by van der Waals forces. For substrates chemically more susceptible to the high anodic voltage, we show that the electrochemical setup can be adapted by placing the latter between the wireless graphite and the stainless steel feeder anode. This method is straightforward, inexpensive, environmentally-friendly, and could be easily scaled up for high yield and large area production of rGO thin films.

  20. Reduced Graphene Oxide Thin Film on Conductive Substrates by Bipolar Electrochemistry.

    PubMed

    Anis, Allagui; Mohammad, Ali Abdelkareem; Hussain, Alawadhi; Ahmed, S Elwakil

    2016-01-01

    Recent years have shown an increased interest in developing manufacturing processes for graphene and its derivatives that consider the environmental impact and large scale cost-effectiveness. However, today's most commonly used synthesis routes still suffer from their excessive use of harsh chemicals and/or the complexity and financial cost of the process. Furthermore, the subsequent transfer of the material onto a substrate makes the overall process even more intricate and time-consuming. Here we describe a single-step, single-cell preparation procedure of metal-supported reduced graphene oxide (rGO) using the principle of bipolar electrochemistry of graphite in deionized water. Under the effect of an electric field between two stainless steel feeder electrodes, grapheme layers at the anodic pole of the wireless graphite were oxidized into colloidal dispersion of GO, which migrated electrophoretically towards the anodic side of the cell, and deposited in the form of rGO (d(002) = 0.395 nm) by van der Waals forces. For substrates chemically more susceptible to the high anodic voltage, we show that the electrochemical setup can be adapted by placing the latter between the wireless graphite and the stainless steel feeder anode. This method is straightforward, inexpensive, environmentally-friendly, and could be easily scaled up for high yield and large area production of rGO thin films. PMID:26883173

  1. Gate stack dielectric degradation of rare-earth oxides grown on high mobility Ge substrates

    NASA Astrophysics Data System (ADS)

    Shahinur Rahman, Md.; Evangelou, E. K.; Konofaos, N.; Dimoulas, A.

    2012-11-01

    We report on the reliability characteristics and their analysis, of rare-earth oxides (REOs) dielectric degradation, when used as interfacial buffer layers together with HfO2 high-k films (REOs/HfO2) on high mobility Ge substrates. Metal-oxide-semiconductor (MOS) devices with these stacks, show dissimilar charge trapping phenomena under varying levels of constant-voltage-stress (CVS) conditions, influencing the measured densities of the interface (Nit) and border (NBT) traps. In the present study, we report on C-Vg hysteresis curves related to both Nit and NBT. We propose a new model based on the Maxwell-Wagner mechanism, and this model explains the current decay transient observed under CVS bias from low to higher fields of MOS gate stack devices grown on Ge substrates. The proposed model is unlike to those used for other MOS devices. Finally, CVS measurements for very long times at moderate fields reveal an initial current decay due to relaxation, followed by charge trapping and generation of stress-induced leakage which eventually lead to hard breakdown.

  2. Synthesis of reduced graphene oxide/ZnO nanorods composites on graphene coated PET flexible substrates

    SciTech Connect

    Huang, Lei Guo, Guilue; Liu, Yang; Chang, Quanhong; Shi, Wangzhou

    2013-10-15

    Graphical abstract: - Highlights: • ZnO nanorods synthesized on CVD-graphene and rGO surfaces, respectively. • ZnO/CVD-graphene and ZnO/rGO form a distinctive porous 3D structure. • rGO/ZnO nanostructures possibility in energy storage devices. - Abstract: In this work, reduced graphene oxide (rGO)/ZnO nanorods composites were synthesized on graphene coated PET flexible substrates. Both chemical vapor deposition (CVD) graphene and reduced graphene oxide (rGO) films were prepared following by hydrothermal growth of vertical aligned ZnO nanorods. Reduced graphene sheets were then spun coated on the ZnO materials to form a three dimensional (3D) porous nanostructure. The morphologies of the ZnO/CVD graphene and ZnO/rGO were investigated by SEM, which shows that the ZnO nanorods grown on rGO are larger in diameters and have lower density compared with those grown on CVD graphene substrate. As a result of fact, the rough surface of nano-scale ZnO on rGO film allows rGO droplets to seep into the large voids of ZnO nanorods, then to form the rGO/ZnO hierarchical structure. By comparison of the different results, we conclude that rGO/ZnO 3D nanostructure is more desirable for the application of energy storage devices.

  3. Designing interlayers to improve the mechanical reliability of transparent conductive oxide coatings on flexible substrates

    SciTech Connect

    Kim, Eun-Hye; Yang, Chan-Woo; Park, Jin-Woo

    2012-05-01

    In this study, we investigate the effect of interlayers on the mechanical properties of transparent conductive oxide (TCO) on flexible polymer substrates. Indium tin oxide (ITO), which is the most widely used TCO film, and Ti, which is the most widely used adhesive interlayer, are selected as the coating and the interlayer, respectively. These films are deposited on the polymer substrates using dc-magnetron sputtering to achieve varying thicknesses. The changes in the following critical factors for film cracking and delamination are analyzed: the internal stress ({sigma}{sup i}) induced in the coatings during deposition using a white light interferometer, the crystallinity using a transmission electron microscope, and the surface roughness of ITO caused by the interlayer using an atomic force microscope. The resistances to the cracking and delamination of ITO are evaluated using a fragmentation test. Our tests and analyses reveal the important role of the interlayers, which significantly reduce the compressive {sigma}{sup i} that is induced in the ITO and increase the resistance to the buckling delamination of the ITO. However, the relaxation of {sigma}{sup i} is not beneficial to cracking because there is less compensation for the external tension as {sigma}{sup i} further decreases. Based on these results, the microstructural control is revealed as a more influential factor than {sigma}{sup i} for improving crack resistance.

  4. Reduced Graphene Oxide Thin Film on Conductive Substrates by Bipolar Electrochemistry

    PubMed Central

    Anis, Allagui; Mohammad, Ali Abdelkareem; Hussain, Alawadhi; Ahmed, S. Elwakil

    2016-01-01

    Recent years have shown an increased interest in developing manufacturing processes for graphene and its derivatives that consider the environmental impact and large scale cost-effectiveness. However, today’s most commonly used synthesis routes still suffer from their excessive use of harsh chemicals and/or the complexity and financial cost of the process. Furthermore, the subsequent transfer of the material onto a substrate makes the overall process even more intricate and time-consuming. Here we describe a single-step, single-cell preparation procedure of metal-supported reduced graphene oxide (rGO) using the principle of bipolar electrochemistry of graphite in deionized water. Under the effect of an electric field between two stainless steel feeder electrodes, grapheme layers at the anodic pole of the wireless graphite were oxidized into colloidal dispersion of GO, which migrated electrophoretically towards the anodic side of the cell, and deposited in the form of rGO (d(002) = 0.395 nm) by van der Waals forces. For substrates chemically more susceptible to the high anodic voltage, we show that the electrochemical setup can be adapted by placing the latter between the wireless graphite and the stainless steel feeder anode. This method is straightforward, inexpensive, environmentally-friendly, and could be easily scaled up for high yield and large area production of rGO thin films. PMID:26883173

  5. Microstructural characteristics of tin oxide-based thin films on (0001) Al2O3 substrates: effects of substrate temperature and RF power during co-sputtering.

    PubMed

    Hwang, Sooyeon; Lee, Ju Ho; Kim, Young Yi; Yun, Myeong Goo; Lee, Kwan-Hun; Lee, Jeong Yong; Cho, Hyung Koun

    2014-12-01

    While tin oxides such as SnO and SnO2 are widely used in various applications, surprisingly, only a limited number of reports have been presented on the microstructural characteristics of tin oxide thin films grown under various growth conditions. In this paper, the effects of the substrate temperature and content of foreign Zn ion on the microstructural characteristics of tin oxide thin films grown by radio-frequency magnetron sputtering were investigated. The increase in substrate temperature induced change in the stoichiometry of the thin films from SnO(1+x) to SnO(2-x). Additionally, the phase contrast in the transmission electron microscopy image revealed that SnO(1+x) and SnO(2-x) phases were alternating in thin films and the width of each phase became narrower at high substrate temperature. The ternary zinc tin oxide thin films were deposited using the co-sputtering method. As the ZnO target power increased, the crystallinity of the thin films became poly-crystalline, and then showed improved crystallinity again with two types of phases. PMID:25970980

  6. Investigation into the role of NaCL deposited on oxide and metal substrates in the initiation of hot corrosion

    NASA Technical Reports Server (NTRS)

    Birks, N.

    1981-01-01

    The conversion to Na2SO4 of NaCl deposited on oxide substrates was studied as a function of temperature, in air with various SO2 and H2O partial pressures. The substrate was either a pure oxide or an oxide scale growing on a metal specimen. The progress of the reaction was observed using the SEM-EDAX technique to monitor morphological effects and, as far as possible, establish the rate of the process. The physical characteristics of the interaction between salt and substrate were also examined with particular reference to physical damage to the underlying oxide, especially when this is a scale on a metal specimen. An effort was also made to establish the conditions under which liquid phases may form and the mechanisms by which they form.

  7. Regulatory role for the arginine-nitric oxide pathway in metabolism of energy substrates.

    PubMed

    Jobgen, Wenjuan Shi; Fried, Susan K; Fu, Wenjiang J; Meininger, Cynthia J; Wu, Guoyao

    2006-09-01

    Nitric oxide (NO) is synthesized from L-arginine by NO synthase in virtually all cell types. Emerging evidence shows that NO regulates the metabolism of glucose, fatty acids and amino acids in mammals. As an oxidant, pathological levels of NO inhibit nearly all enzyme-catalyzed reactions through protein oxidation. However, as a signaling molecule, physiological levels of NO stimulate glucose uptake as well as glucose and fatty acid oxidation in skeletal muscle, heart, liver and adipose tissue; inhibit the synthesis of glucose, glycogen, and fat in target tissues (e.g., liver and adipose); and enhance lipolysis in adipocytes. Thus, an inhibition of NO synthesis causes hyperlipidemia and fat accretion in rats, whereas dietary arginine supplementation reduces fat mass in diabetic fatty rats. The putative underlying mechanisms may involve multiple cyclic guanosine-3',5'-monophosphate-dependent pathways. First, NO stimulates the phosphorylation of adenosine-3',5'-monophosphate-activated protein kinase, resulting in (1) a decreased level of malonyl-CoA via inhibition of acetyl-CoA carboxylase and activation of malonyl-CoA decarboxylase and (2) a decreased expression of genes related to lipogenesis and gluconeogenesis (glycerol-3-phosphate acyltransferase, sterol regulatory element binding protein-1c and phosphoenolpyruvate carboxykinase). Second, NO increases the phosphorylation of hormone-sensitive lipase and perilipins, leading to the translocation of the lipase to the neutral lipid droplets and, hence, the stimulation of lipolysis. Third, NO activates expression of peroxisome proliferator-activated receptor-gamma coactivator-1alpha, thereby enhancing mitochondrial biogenesis and oxidative phosphorylation. Fourth, NO increases blood flow to insulin-sensitive tissues, promoting substrate uptake and product removal via the circulation. Modulation of the arginine-NO pathway through dietary supplementation with L-arginine or L-citrulline may aid in the prevention and

  8. Hippocampus ghrelin signaling mediates appetite through lateral hypothalamic orexin pathways

    PubMed Central

    Hsu, Ted M; Hahn, Joel D; Konanur, Vaibhav R; Noble, Emily E; Suarez, Andrea N; Thai, Jessica; Nakamoto, Emily M; Kanoski, Scott E

    2015-01-01

    Feeding behavior rarely occurs in direct response to metabolic deficit, yet the overwhelming majority of research on the biology of food intake control has focused on basic metabolic and homeostatic neurobiological substrates. Most animals, including humans, have habitual feeding patterns in which meals are consumed based on learned and/or environmental factors. Here we illuminate a novel neural system regulating higher-order aspects of feeding through which the gut-derived hormone ghrelin communicates with ventral hippocampus (vHP) neurons to stimulate meal-entrained conditioned appetite. Additional results show that the lateral hypothalamus (LHA) is a critical downstream substrate for vHP ghrelin-mediated hyperphagia and that vHP ghrelin activated neurons communicate directly with neurons in the LHA that express the neuropeptide, orexin. Furthermore, activation of downstream orexin-1 receptors is required for vHP ghrelin-mediated hyperphagia. These findings reveal novel neurobiological circuitry regulating appetite through which ghrelin signaling in hippocampal neurons engages LHA orexin signaling. DOI: http://dx.doi.org/10.7554/eLife.11190.001 PMID:26745307

  9. Lipid oxidation in minced beef meat with added Krebs cycle substrates to stabilise colour.

    PubMed

    Yi, G; Grabež, V; Bjelanovic, M; Slinde, E; Olsen, K; Langsrud, O; Phung, V T; Haug, A; Oostindjer, M; Egelandsdal, B

    2015-11-15

    Krebs cycle substrates (KCS) can stabilise the colour of packaged meat by oxygen reduction. This study tested whether this reduction releases reactive oxygen species that may lead to lipid oxidation in minced meat under two different storage conditions. KCS combinations of succinate and glutamate increased peroxide forming potential (PFP, 1.18-1.32 mmol peroxides/kg mince) and thiobarbituric acid reactive substances (TBARS, 0.30-0.38 mg malondialdehyde (MDA) equivalents/kg mince) under low oxygen storage conditions. Both succinate and glutamate were metabolised. Moreover, under high oxygen (75%) storage conditions, KCS combinations of glutamate, citrate and malate increased PFP (from 1.22 to 1.29 mmol peroxides/kg) and TBARS (from 0.37 to 0.40 mg MDA equivalents/kg mince). Only glutamate was metabolised. The KCS combinations that were added to stabilise colour were metabolised during storage, and acted as pro-oxidants that promoted lipid oxidation in both high and low oxygen conditions. PMID:25977064

  10. Effect of substrate availability on nitrous oxide production by deammonification processes under anoxic conditions

    PubMed Central

    Schneider, Yvonne; Beier, Maike; Rosenwinkel, Karl‐Heinz

    2012-01-01

    Summary Due to its high global warming potential, nitrous oxide (N2O) emissions from wastewater treatment processes have recently received a high degree of attention. Nevertheless, there is still a lack of information regarding the microbiological processes leading to N2O production. In this study, two lab‐scale sequencing batch reactors were operated with deammonification biomass to investigate the role of denitrification and the influence of substrate availability regarding N2O formation during the anoxic phase of deammonification. Three different operational phases were established: within the first phase conversion by anammox was favoured and after a transition phase, denitrification activity was promoted. Low nitrous oxide production was observed during stable operation aiming for anammox conversion. Pulsed inflow of the wastewater containing ammonium (NH4+) and nitrite (NO2‐) led to increased N2O production rates. Within the period of denitrification as dominating nitrogen conversion process, the nitrous oxide concentration level was higher during continuous inflow conditions, but the reaction to pulsed inflow was less pronounced. The results indicated that denitrification was responsible for N2O formation from the deammonification biomass. Operational settings to achieve suppression of denitrification processes to a large extend were deducted from the results of the experiments. PMID:22296600

  11. Effect of substrate availability on nitrous oxide production by deammonification processes under anoxic conditions.

    PubMed

    Schneider, Yvonne; Beier, Maike; Rosenwinkel, Karl-Heinz

    2012-05-01

    Due to its high global warming potential, nitrous oxide (N(2)O) emissions from wastewater treatment processes have recently received a high degree of attention. Nevertheless, there is still a lack of information regarding the microbiological processes leading to N(2)O production. In this study, two lab-scale sequencing batch reactors were operated with deammonification biomass to investigate the role of denitrification and the influence of substrate availability regarding N(2)O formation during the anoxic phase of deammonification. Three different operational phases were established: within the first phase conversion by anammox was favoured and after a transition phase, denitrification activity was promoted. Low nitrous oxide production was observed during stable operation aiming for anammox conversion. Pulsed inflow of the wastewater containing ammonium (NH(4)(+)) and nitrite (NO(2)(-)) led to increased N(2)O production rates. Within the period of denitrification as dominating nitrogen conversion process, the nitrous oxide concentration level was higher during continuous inflow conditions, but the reaction to pulsed inflow was less pronounced. The results indicated that denitrification was responsible for N(2)O formation from the deammonification biomass. Operational settings to achieve suppression of denitrification processes to a large extend were deducted from the results of the experiments. PMID:22296600

  12. Dewatering of saline sewage sludge using iron-oxidizing bacteria: Effect of substrate concentration.

    PubMed

    Wong, Jonathan W C; Murugesan, Kumarasamy; Selvam, Ammaiyappan; Ravindran, Balasubramanian; Kurade, Mayur B; Yu, Shuk-Man

    2016-08-01

    This study investigated the improvement in dewaterability of activated sludge (ACS) and anaerobically digested sludge (ADS) through bioacidification approach using iron-oxidizing bacterium, Acidithiobacillus ferrooxidans. ACS and ADS were treated with A. ferrooxidans culture with addition of different concentrations of energy substrate, in terms of Fe(2+):sludge solids ratio (0:1, 0.01:1, 0.05:1 and 0.1:1), and the dewaterability was assessed by determining the capillary suction time (CST), time to filter (TTF) and specific resistance to filtration (SRF) of the sludge. The results revealed that the levels of Fe(2+) significantly influenced the sludge acidification (pH⩽3). The CST, TTF and SRF values rapidly decreased in treated sludge, indicating that dewaterability of the sludge was significantly (p<0.05) improved than untreated sludge. This investigation clearly demonstrates that A. ferrooxidans culture, as biogenic flocculant, can be potentially used for improving the sludge flocculation, stabilization and dewaterability. PMID:27095409

  13. Oxidative potential of some endophytic fungi using 1-indanone as a substrate.

    PubMed

    Fill, Taicia Pacheco; da Silva, Jose Vinicius; de Oliveira, Kleber Thiago; da Silva, Bianca Ferreira; Rodrigues-Fo, Edson

    2012-06-01

    The oxidative potential of the fungus Penicillium brasilianum, a strain isolated as an endophyte from a Meliaceae plant (Melia azedarach), was investigated using 1-indanone as a substrate to track the production of monooxygenases. The fungus produced the dihydrocoumarin from 1-indanone with the classical Baeyer-Villiger reaction regiochemistry, and (-)-(R)-3-hydroxy-1-indanone with 78% ee. Minor compounds resulting from lipase and SAM activities were also detected. The biotransformation procedures were also applied to a collection of Penicillium and Aspergillus fungi obtained from M. azedarach and Murraya paniculata. The results showed that Baeyer-Villiger were mostly active in fungi isolated from M. azedarach. Almost all of the fungi tested produced 3-hydroxy-1-indanone.. PMID:22573162

  14. Green luminescent center in undoped zinc oxide films deposited on silicon substrates

    NASA Astrophysics Data System (ADS)

    Lin, Bixia; Fu, Zhuxi; Jia, Yunbo

    2001-08-01

    The photoluminescence (PL) spectra of the undoped ZnO films deposited on Si substrates by dc reactive sputtering have been studied. There are two emission peaks, centered at 3.18 eV (UV) and 2.38 eV (green). The variation of these peak intensities and that of the I-V properties of the ZnO/Si heterojunctions were investigated at different annealing temperatures and atmospheres. The defect levels in ZnO films were also calculated using the method of full-potential linear muffin-tin orbital. It is concluded that the green emission corresponds to the local level composed by oxide antisite defect OZn rather than oxygen vacancy VO, zinc vacancy VZn, interstitial zinc Zni, and interstitial oxygen Oi.

  15. Purely sonochemical route for oriented zinc oxide nanowire growth on arbitrary substrate

    NASA Astrophysics Data System (ADS)

    Nayak, Avinash P.; Katzenmeyer, Aaron M.; Kim, Ja-Yeon; Kwon, Min Ki; Gosho, Yasuhiro; Islam, M. Saif

    2010-04-01

    We report a simple sonochemical method for the seeding and synthesis of Zinc Oxide nanowire arrays that can be formed on a number of substrates that are stable in alcohol and aqueous solution. Vertically aligned ZnO NWs were synthesized from a single solution at room-ambient via ultrasonic excitation. Prior to the NW growth, a ZnO seed layer was deposited using the same system with a different solution. The optimal conditions to produce a high density of oriented wires along with their optical characteristics are presented for ZnO NWs with a significantly high growth rate compared with traditional growth techniques such as evaporation, chemical vapor deposition and sputtering. Our method promises a mass-manufacturable process for fast and inexpensive ZnO NW production for practical low cost electronics, photonics and energy conversion applications.

  16. Laser scribing of indium tin oxide (ITO) thin films deposited on various substrates for touch panels

    NASA Astrophysics Data System (ADS)

    Tseng, Shih-Feng; Hsiao, Wen-Tse; Huang, Kuo-Cheng; Chiang, Donyau; Chen, Ming-Fei; Chou, Chang-Pin

    2010-12-01

    In this study, a Nd:YAG laser with wavelength of 1064 nm is used to scribe the indium tin oxide (ITO) thin films coated on three types of substrate materials, i.e. soda-lime glass, polycarbonate (PC), and cyclic-olefin-copolymer (COC) materials with thickness of 20 nm, 30 nm, and 20 nm, respectively. The effect of exposure time adjusted from 10 μs to 100 μs on the ablated mark width, depth, and electrical properties of the scribed film was investigated. The maximum laser power of 2.2 W was used to scribe these thin films. In addition, the surface morphology, surface reaction, surface roughness, optical properties, and electrical conductivity properties were measured by a scanning electron microscope, a three-dimensional confocal laser scanning microscope, an atomic force microscope, and a four-point probe. The measured results of surface morphology show that the residual ITO layer was produced on the scribed path with the laser exposure time at 10 μs and 20 μs. The better edge qualities of the scribed lines can be obtained when the exposure time extends from 30 μs to 60 μs. When the laser exposure time is longer than 60 μs, the partially burned areas of the scribed thin films on PC and COC substrates are observed. Moreover, the isolated line width and resistivity values increase when the laser exposure time increases.

  17. THz behavior of indium-tin-oxide films on p-Si substrates

    SciTech Connect

    Brown, E. R. Zhang, W-D.; Chen, H.; Mearini, G. T.

    2015-08-31

    This paper reports broadband THz free-space transmission measurements and modeling of indium-tin-oxide (ITO) thin films on p-doped Si substrates. Two such samples having ITO thickness of 50 and 100 nm, and DC sheet conductance 260 and 56 Ω/sq, respectively, were characterized between 0.2 and 1.2 THz using a frequency-domain spectrometer. The 50-nm-film sample displayed very flat transmittance over the 1-THz bandwidth, suggesting it is close to the critical THz sheet conductance that suppresses multi-pass interference in the substrate. An accurate transmission-line-based equivalent circuit is developed to explain the effect, and then used to show that the net reflectivity and absorptivity necessarily oscillate with frequency. This has important implications for the use of thin-film metallic coupling layers on THz components and devices, such as detectors and sources. Consistent with previous reported results, the sheet conductance that best fits the THz transmittance data is roughly 50% higher than the DC values for both samples.

  18. Flexible electrochromics: magnetron sputtered tungsten oxide (WO3-x) thin films on Lexan (optically transparent polycarbonate) substrates

    NASA Astrophysics Data System (ADS)

    Uday Kumar, K.; Murali, Dhanya S.; Subrahmanyam, A.

    2015-06-01

    Tungsten oxide (WO3-x) based electrochromics on flexible substrates is a topic of recent interest. The present communication reports the electrochromic properties of WO3-x thin films grown on lexan, an optically transparent polycarbonate thermoplastic substrate. The WO3-x films are prepared at room temperature (300 K) by the reactive DC magnetron sputtering technique. The physical properties of metal oxide thin films are known to be controlled by the oxygen stoichiometry of the film. In the present work, the WO3-x thin films are prepared by varying the oxygen flow rates. All the WO3-x thin films are amorphous in nature. The electrochromic performance of the WO3-x thin films is evaluated by cyclic voltammetry measurements on tin doped indium oxide (ITO) coated lexan and glass substrates. The optical band gap of WO3-x thin films grown on lexan substrates (at any given oxygen flow rate) is significantly higher than those grown on glass substrates. The coloration efficiency of WO3-x thin films (at an oxygen flow rate of 10 sccm) on lexan substrates is: 143.9 cm2 C-1 which is higher compared to that grown on glass: 90.4 cm2 C-1.

  19. Electronic interface properties of silicon substrates after ozone based wet-chemical oxidation studied by SPV measurements

    NASA Astrophysics Data System (ADS)

    Angermann, Heike; Wolke, Klaus; Gottschalk, Christiane; Moldovan, Ana; Roczen, Maurizio; Fittkau, Jens; Zimmer, Martin; Rentsch, Jochen

    2012-08-01

    The preparation of ultra-thin oxide layers on mono-crystalline silicon substrate surfaces with ozone dissolved in ultra pure water at ambient temperature was investigated as a low cost alternative to current wet-chemical cleaning and passivation processes in solar cell manufacturing. Surface photovoltage technique was applied as fast, nondestructive, and surface sensitive method, to provide detailed information about the influence of oxidation rate and substrate surface morphology on electronic properties of the oxidised silicon interfaces and subsequently prepared hydrogen terminated surfaces. Sequences of wet-chemical oxidation in ozone containing ultra pure water and subsequent oxide removal in diluted hydrofluoric acid solution could be utilised to prepare hydrophobic substrates, which are predominantly required as starting point for layer deposition and contact formation. On so prepared hydrogen-terminated substrates values of interface state densities Dit,min ≈ 5 × 1011 eV-1 cm-2 could be achieved, comparable to values obtained on the same substrates by the standard RCA process followed by HF dip.

  20. Measurement of β-oxidation capacity of biological samples by respirometry: a review of principles and substrates.

    PubMed

    Ojuka, Edward; Andrew, Brittany; Bezuidenhout, Nicole; George, Siddiqah; Maarman, Gerald; Madlala, Hlengiwe P; Mendham, Amy; Osiki, Prisca Ofure

    2016-05-01

    Oxidation of fatty acids is a major source of energy in the heart, liver, and skeletal muscle. It can be measured accurately using respirometry in isolated mitochondria, intact cells, and permeabilized cells or tissues. This technique directly measures the rate of oxygen consumption or flux at various respiratory states when appropriate substrates, uncouplers, and inhibitors are used. Acylcarnitines such as palmitoylcarnitine or octanoylcarnitine are the commonly used substrates. The β-oxidation pathway is prone to feedforward inhibition resulting from accumulation of short-chain acyl-CoA and depletion of CoA, but inclusion of malate or carnitine prevents accumulation of these intermediaries and CoA depletion. PMID:26908505

  1. Low-cost flexible supercapacitors based on laser reduced graphene oxide supported on polyethylene terephthalate substrate

    NASA Astrophysics Data System (ADS)

    Ghoniem, Engy; Mori, Shinsuke; Abdel-Moniem, Ahmed

    2016-08-01

    A controlled high powered CO2 laser system is used to reduce and pattern graphene oxide (GO) film supported onto a flexible polyethylene terephthalate (PET) substrate. The laser reduced graphene oxide (rGO) film is characterized and evaluated electrochemically in the absence and presence of an overlying anodicaly deposited thin film of pseuodcapactive MnO2 as electrodes for supercapacitor applications using aqueous electrolyte. The laser treatment of the GO film leads to an overlapped structure of defective multi-layer rGO sheets with an electrical conductivity of 273 S m-1. The rGO and MnO2/rGO electrodes exhibit specific capacitance in the range of 82-107 and 172-368 Fg-1 at applied current range of 0.1-1.0 mA cm-2 and retain 98 and 95% of their initial capacitances after 2000 cycles at a current density of 1.0 mA cm-2, respectively. Also, the rGO is assigned as an electrode material for flexible conventionally stacked and interdigitated in-plane supercapacitor structures using gel electrolyte. Three electrode architectures of 2, 4, and 6 sub-electrodes are studied for the interdigital in-plane design. The device with interdigital 6 sub-electrodes architecture I-PS(6) delivers power density of 537.1 Wcm-3 and an energy density of 0.45 mWh cm-3.

  2. [Oxidation of sulfur-containing substrates by an association of acidophilic chemolithotrophic microorganisms].

    PubMed

    Revenko, A A; Melamud, V S; Krasil'nikov, G S; Pivovarova, T A; Belyĭ, V A; Kondrat'eva, T F

    2009-01-01

    Quantitative and qualitative changes in the content of elements in the solid and liquid phases occurred as the pulp moved through fermenters during biooxidation of an ore flotation concentrate. The association of microorganisms were adapted for utilizing sulfur-containing substrates; however, the rate of their oxidation was insufficient, which led to an increase in the amount of sodium cyanide required for gold recovery. The replacement of one-fourth of the liquid phase of the pulp (density, 13%) with a mineral medium without an energy source, the fractional addition of FeSO4 x 7H2O (1 g/l per day), and the improvement of pulp aeration made it possible to increase the content of SO4(2-) by 80.7, 86.2, and 58.5%, respectively. When one-fourth of the liquid phasa of the pulp (density, 24%) was replaced with a mineral medium without an energy source, the rate of additional oxidation of sulfide minerals increased, which increased the efficiency of gold extraction into solution and gold recovery on charcoal by 3.4 and 3.6%, respectively, and reduced sodium cyanide consumption by 3 kg/ton. PMID:19764615

  3. Thermal stability studies of plasma sprayed yttrium oxide coatings deposited on pure tantalum substrate

    NASA Astrophysics Data System (ADS)

    Nagaraj, A.; Anupama, P.; Mukherjee, Jaya; Sreekumar, K. P.; Satpute, R. U.; Padmanabhan, P. V. A.; Gantayet, L. M.

    2010-02-01

    Plasma sprayed Yttrium oxide is used for coating of crucibles and moulds that are used at high temperature to handle highly reactive molten metals like uranium, titanium, chromium, and beryllium. The alloy bond layer is severely attacked by the molten metal. This commonly used layer contributes to the impurity addition to the pure liquid metal. Yttrium oxide was deposited on tantalum substrates (25 mm × 10mm × 1mm thk and 40 mm × 8mm × 1mm thk) by atmospheric plasma spray technique with out any bond coat using optimized coating parameters. Resistance to thermal shock was evaluated by subjecting the coated specimens, to controlled heating and cooling cycles between 300K to 1600K in an induction furnace in argon atmosphere having <= 0.1ppm of oxygen. The experiments were designed to examine the sample tokens by both destructive and non-destructive techniques, after a predetermined number of thermal cycles. The results upto 24 thermal cycles of 25 mm × 10mm × 1mm thk coupons and upto 6 cycles of 40 mm × 8mm × 1mm thk coupons are discussed. The coatings produced with the optimized parameters were found to exhibit excellent thermal shock resistance.

  4. Appetitive vs. Aversive conditioning in humans.

    PubMed

    Andreatta, Marta; Pauli, Paul

    2015-01-01

    In classical conditioning, an initially neutral stimulus (conditioned stimulus, CS) becomes associated with a biologically salient event (unconditioned stimulus, US), which might be pain (aversive conditioning) or food (appetitive conditioning). After a few associations, the CS is able to initiate either defensive or consummatory responses, respectively. Contrary to aversive conditioning, appetitive conditioning is rarely investigated in humans, although its importance for normal and pathological behaviors (e.g., obesity, addiction) is undeniable. The present study intents to translate animal findings on appetitive conditioning to humans using food as an US. Thirty-three participants were investigated between 8 and 10 am without breakfast in order to assure that they felt hungry. During two acquisition phases, one geometrical shape (avCS+) predicted an aversive US (painful electric shock), another shape (appCS+) predicted an appetitive US (chocolate or salty pretzel according to the participants' preference), and a third shape (CS-) predicted neither US. In a extinction phase, these three shapes plus a novel shape (NEW) were presented again without US delivery. Valence and arousal ratings as well as startle and skin conductance (SCR) responses were collected as learning indices. We found successful aversive and appetitive conditioning. On the one hand, the avCS+ was rated as more negative and more arousing than the CS- and induced startle potentiation and enhanced SCR. On the other hand, the appCS+ was rated more positive than the CS- and induced startle attenuation and larger SCR. In summary, we successfully confirmed animal findings in (hungry) humans by demonstrating appetitive learning and normal aversive learning. PMID:26042011

  5. Appetitive vs. Aversive conditioning in humans

    PubMed Central

    Andreatta, Marta; Pauli, Paul

    2015-01-01

    In classical conditioning, an initially neutral stimulus (conditioned stimulus, CS) becomes associated with a biologically salient event (unconditioned stimulus, US), which might be pain (aversive conditioning) or food (appetitive conditioning). After a few associations, the CS is able to initiate either defensive or consummatory responses, respectively. Contrary to aversive conditioning, appetitive conditioning is rarely investigated in humans, although its importance for normal and pathological behaviors (e.g., obesity, addiction) is undeniable. The present study intents to translate animal findings on appetitive conditioning to humans using food as an US. Thirty-three participants were investigated between 8 and 10 am without breakfast in order to assure that they felt hungry. During two acquisition phases, one geometrical shape (avCS+) predicted an aversive US (painful electric shock), another shape (appCS+) predicted an appetitive US (chocolate or salty pretzel according to the participants' preference), and a third shape (CS–) predicted neither US. In a extinction phase, these three shapes plus a novel shape (NEW) were presented again without US delivery. Valence and arousal ratings as well as startle and skin conductance (SCR) responses were collected as learning indices. We found successful aversive and appetitive conditioning. On the one hand, the avCS+ was rated as more negative and more arousing than the CS– and induced startle potentiation and enhanced SCR. On the other hand, the appCS+ was rated more positive than the CS– and induced startle attenuation and larger SCR. In summary, we successfully confirmed animal findings in (hungry) humans by demonstrating appetitive learning and normal aversive learning. PMID:26042011

  6. Neuroendocrine regulation of appetitive ingestive behavior

    PubMed Central

    Keen-Rhinehart, Erin; Ondek, Katelynn; Schneider, Jill E.

    2013-01-01

    Food availability in nature is often irregular, and famine is commonplace. Increased motivation to engage in ingestive behaviors increases the chance of survival, providing additional potential opportunities for reproduction. Because of the advantages conferred by entraining ingestive behavior to environmental conditions, neuroendocrine mechanisms regulating the motivation to acquire and ingest food have evolved to be responsive to exogenous (i.e., food stored for future consumption) and endogenous (i.e., body fat stores) fuel availability. Motivated behaviors like eating occur in two phases. The appetitive phase brings animals into contact with food (e.g., foraging, food hoarding), and the more reflexive consummatory phase results in ingestion (e.g., chewing, swallowing). Quantifiable appetitive behaviors are part of the natural ingestive behavioral repertoire of species such as hamsters and humans. This review summarizes current knowledge about neuroendocrine regulators of ingestive behavior, with an emphasis appetitive behavior. We will discuss hormonal regulators of appetitive ingestive behaviors, including the orexigenic hormone ghrelin, which potently stimulates foraging and food hoarding in Siberian hamsters. This section includes a discussion of the hormone leptin, its relation to endogenous fat stores, and its role in food deprivation-induced increases in appetitive ingestive behaviors. Next, we discuss how hormonal regulators interact with neurotransmitters involved in the regulation of ingestive behaviors, such as neuropeptide Y (NPY), agouti-related protein (AgRP) and α-melanocyte stimulating hormone (α-MSH), to regulate ingestive behavior. Finally, we discuss the potential impact that perinatal nutrient availability can have on the neuroendocrine regulation of ingestive behavior. Understanding the hormonal mechanisms that connect metabolic fuel availability to central appetite regulatory circuits should provide a better understanding of the

  7. Role of guar fiber in appetite control.

    PubMed

    Rao, Theertham Pradyumna

    2016-10-01

    Appetite control and reduction of additional calorie intake may be a logical approach for proper weight management. Viscous dietary fibers are effective in appetite control but difficult to apply in normal serving sizes in foods and nutritional supplements due to their viscosity and required high doses. Guar fiber popularly known as partially hydrolyzed guar gum (PHGG) is near non-viscous soluble fiber that has been proven effective in providing many physiological benefits. Guar fiber has also been identified as potential natural food and nutritional supplement ingredient for appetite control. The aim of this review is to summarize all the clinical studies pertinent to its effects on appetite control in normal subjects and postulate the mechanism of action. Guar fiber exhibited appetite control via delaying the colonic transit time of digested food, stimulation of satiety hormone cholecystokinin (CCK) and induction of prolonged perception of post-meal satiation and satiety effects. Regular intake of guar fiber at a dose of 2g/serving provided significant sustained post-meal satiation effects and minimized the inter-meal calorie intake by about 20% in normal subjects. The intake of guar fiber alone at a dose >5g/serving or its combination with protein (2.6g guar fiber+8g protein/serving) showed acute satiety effects in normal subjects. Guar fiber containing >85% dietary fiber, with clear solubility and negligible taste impact, may be an ideal natural dietary fiber for use in food and supplement applications at low dosage levels for appetite control. PMID:27317834

  8. Cyclic Oxidation Behavior of Cold Sprayed CuCrAl-Coated and Uncoated GRCop-84 Substrates for Space Launch Vehicles

    NASA Technical Reports Server (NTRS)

    Raj, S. V.; Barrett, C.; Karthikeyan, J.; Garlick, R.

    2006-01-01

    A newly developed Cu-23 (wt %) Cr-5%Al (CuCrAl) alloy shown to resist hydridation and oxidation in an as-cast form is currently being considered as a protective coating for GRCop-84, which is an advanced copper alloy containing 8 (at.%) Cr and 4 (at.%) Nb. The coating was deposited on GRCop-84 substrates by the cold spray deposition technique. Cyclic oxidation tests conducted in air on both coated and uncoated substrates between 773 and 1073 K revealed that the coating remained intact and protected the substrate up to 1073 K. No significant weight loss of the coated specimens were observed at 773 and 873 K even after a cumulative cyclic time of 500 h. About a 10 percent weight loss observed at 973 and 1073 K was attributed to the excessive oxidation of the uncoated sides. In contrast, the uncoated substrate lost as much as 80 percent of its original weight under similar test conditions. It is concluded that the cold sprayed CuCrAl coating is suitable for protecting GRCop-84 substrates.

  9. Film-edge-induced dislocation generation in silicon substrates. II. Application of the theoretical model for local oxidation processes on (001) silicon substrates

    NASA Astrophysics Data System (ADS)

    Vanhellemont, J.; Amelinckx, S.; Claeys, C.

    1987-03-01

    A theoretical model which allows prediction of the type and of the equilibrium configuration of dislocations generated or captured in fcc substrates at the edges of thin films is applied to local oxidation processes on (001) Czochralski silicon substrates. Nitride film structures aligned along the two most interesting crystallographic directions on the (001) surface, i.e., the <110> and the <100> directions, are studied by high-voltage electron microscopy. The model allows to explain the observed dislocation types including most of the previous reports in the literature. Some numerical examples are given which illustrate the strength of the model to obtain even quantitative information both on the film stresses and on the critical glide force from the observed equilibrium configuration of the defects. Good agreement is obtained between the observed shape and position of the defects and computer simulations based on the model.

  10. Heterologous Expression of Pleurotus eryngii Peroxidase Confirms Its Ability To Oxidize Mn2+ and Different Aromatic Substrates

    PubMed Central

    Ruiz-Dueñas, Francisco Javier; Martínez, María Jesús; Martínez, Ángel T.

    1999-01-01

    A versatile ligninolytic peroxidase has been cloned from Pleurotus eryngii and its allelic variant MnPL2 expressed in Aspergillus nidulans, with properties similar to those of the mature enzyme from P. eryngii. These include the ability to oxidize Mn2+ and aromatic substrates, confirming that this is a new peroxidase type sharing catalytic properties of lignin peroxidase and manganese peroxidase. PMID:10508113

  11. Electrodeposited Manganese Oxides on Three-Dimensional Carbon Nanotube Substrate: Supercapacitive Behaviour in Aqueous and Organic Electrolytes

    SciTech Connect

    Nam,K.W.; Yang,X.

    2009-03-01

    Thin amorphous manganese oxide layers with a thickness of 3-5nm are electrodeposited on a carbon nanotube (CNT) film substrate that has a three-dimensional nanoporous structure (denoted asMnO2/CNT electrode). For the purpose of comparison, manganese oxide films are also electrodeposited on a flat Pt-coated Si wafer substrate (denoted as MnO2 film electrode). The pseudocapacitive properties of the MnO2 film and MnO2/CNT electrodes are examined in both aqueous electrolyte (1.0M KCl) and nonaqueousorganic electrolyte (1.0M LiClO4 in propylene carbonate). While both types of electrode showpseudocapacitive behaviour in the aqueous electrolyte, only the MnO2/CNT electrode does so in the organic electrolyte, due to its high oxide/electrolyte interfacial area and improved electron conduction through the CNT substrate. Compared with the MnO2 film electrode, the MnO2/CNT electrode shows a much higher specific capacitance and better high-rate capability, regardless of the electrolyte used.Use of the organic electrolyte results in a ∼6 times higher specific energy compared with that obtained with the aqueous electrolyte, while maintaining a similar specific power. The construction of a threedimensional nanoporous network structure consisting of a thin oxide layer on a CNT film substrate at the nm scale and the use of an organic electrolyte are promising approaches to improving the specific energyof supercapacitors.

  12. Method of depositing an electrically conductive oxide buffer layer on a textured substrate and articles formed therefrom

    DOEpatents

    Paranthaman, M. Parans; Aytug, Tolga; Christen, David K.

    2003-09-09

    An article with an improved buffer layer architecture includes a substrate having a textured metal surface, and an electrically conductive lanthanum metal oxide epitaxial buffer layer on the surface of the substrate. The article can also include an epitaxial superconducting layer deposited on the epitaxial buffer layer. An epitaxial capping layer can be placed between the epitaxial buffer layer and the superconducting layer. A method for preparing an epitaxial article includes providing a substrate with a metal surface and depositing on the metal surface a lanthanum metal oxide epitaxial buffer layer. The method can further include depositing a superconducting layer on the epitaxial buffer layer, and depositing an epitaxial capping layer between the epitaxial buffer layer and the superconducting layer.

  13. Method of depositing an electrically conductive oxide buffer layer on a textured substrate and articles formed therefrom

    DOEpatents

    Paranthaman, M. Parans; Aytug, Tolga; Christen, David K.

    2005-10-18

    An article with an improved buffer layer architecture includes a substrate having a textured metal surface, and an electrically conductive lanthanum metal oxide epitaxial buffer layer on the surface of the substrate. The article can also include an epitaxial superconducting layer deposited on the epitaxial buffer layer. An epitaxial capping layer can be placed between the epitaxial buffer layer and the superconducting layer. A method for preparing an epitaxial article includes providing a substrate with a metal surface and depositing on the metal surface a lanthanum metal oxide epitaxial buffer layer. The method can further include depositing a superconducting layer on the epitaxial buffer layer, and depositing an epitaxial capping layer between the epitaxial buffer layer and the superconducting layer.

  14. Localized Plasmon-Stimulated Nanochemistry of Graphene Oxide on a SERS Substrate.

    PubMed

    Ramanauskaite, Lina; Xu, Huizhong; Snitka, Valentinas

    2016-03-16

    In recent years, there has been remarkable progress in the reduction and functionalization of graphene oxide (GO) using nanoparticles and high-energy optical photons. Most of these reactions are carried out in solutions, whereas the local modification of GO on solid substrates still remains a challenge. In this work, we demonstrate the local reduction of GO and its further destruction, leading to the synthesis of polyaromatic hydrocarbons (PAHs) stimulated by localized surface plasmons (LSPs). The reduction of GO and the synthesis of PAHs have been carried out on a substrate designed for surface-enhanced Raman spectroscopy (SERS). We found that LSPs initiate the destruction of water molecules entrapped in the nanogaps between silver nanoparticles after the deposition of GO from the aqueous suspension. It was demonstrated that OH radicals, as a result of water decomposition, initiate the reduction of GO, leading to the synthesis of PAHs. The reactions have been observed in real time by using SERS. The measurement of current-voltage (I-V) characteristics through conductive atomic force microscopy (AFM), recorded in an LSP-stimulated area, have shown the increased electrical conductivity (more than ten times) compared with the conductivity of GO. The synthesis of new compounds in the LSP-stimulated area has been confirmed by the appearance of new peaks in the Raman spectra and nonlinear I-V characteristics typical for PAHs. We show that the used method allows the local modification of electrical properties of GO and controlled nanopattering of organic compounds on the surface. PMID:26728625

  15. Fabrication of silver nanoparticles decorated anodic aluminum oxide as the SERS substrate for the detection of pesticide thiram

    NASA Astrophysics Data System (ADS)

    Tan, En-zhong

    2015-07-01

    An efficient surface-enhanced Raman scattering (SERS) substrate is developed based on silver nanoparticles decorated anodic aluminum oxide (Ag/AAO). The AAO templates were fabricated using a two-step anodization approach, and silver nanoparticles (AgNPs) were obtained by thermal decomposition of Ag nitrate in AAO. The structure of Ag/AAO hybrid substrate is characterized by scanning electron microscopy (SEM). The results show that the as-prepared SERS substrates consist of high-density AgNPs with sizes of tens of nanometers. The AgNPs are adsorbed on the surface of AAO template in the form of network structure which is called "hot spot". The SERS enhancement ability of the nanostructure is verified using thiram as probing molecules. The limit of detection is as low as 1×10-9 mol/L. The results indicate that the as-prepared substrate possesses excellent SERS sensitivity, high stability and uniformity enhancement.

  16. Mechanical and piezoelectric properties of zinc oxide nanorods grown on conductive textile fabric as an alternative substrate

    NASA Astrophysics Data System (ADS)

    Khan, Azam; Hussain, Mushtaque; Nur, Omer; Willander, Magnus

    2014-08-01

    The present research is devoted to understanding the mechanism and causes of variation in the piezoelectric potential generated from vertically aligned zinc oxide (ZnO) nanorods (NRs), which were grown on a conductive textile fabric as an alternative substrate by using the aqueous chemical growth method. The piezoelectric voltage was harvested from vertically aligned ZnO NRs having different physical parameters by using atomic force microscopy in contact mode and the variation in the generated piezoelectricity was investigated. The generated output potential indicates that different physical parameters such aspect ratio, crystal size and lattice internal crystal strain have a strong influence on the piezoelectric properties of vertically aligned ZnO NRs, which were grown on a textile fabric. Presented results indicate that textiles can be used as an alternative substrate just like the other conventional substrates, because our results are similar/better than many reported works on conventional substrates.

  17. Method of depositing an electrically conductive oxide film on a textured metallic substrate and articles formed therefrom

    DOEpatents

    Christen, David K.; He, Qing

    2001-01-01

    The present invention provides a biaxially textured laminate article having a polycrystalline biaxially textured metallic substrate with an electrically conductive oxide layer epitaxially deposited thereon and methods for producing same. In one embodiment a biaxially texture Ni substrate has a layer of LaNiO.sub.3 deposited thereon. An initial layer of electrically conductive oxide buffer is epitaxially deposited using a sputtering technique using a sputtering gas which is an inert or forming gas. A subsequent layer of an electrically conductive oxide layer is then epitaxially deposited onto the initial layer using a sputtering gas comprising oxygen. The present invention will enable the formation of biaxially textured devices which include HTS wires and interconnects, large area or long length ferromagnetic and/or ferroelectric memory devices, large area or long length, flexible light emitting semiconductors, ferroelectric tapes, and electrodes.

  18. Method of depositing an electrically conductive oxide film on a textured metallic substrate and articles formed therefrom

    DOEpatents

    Christen, David K.; He, Qing

    2003-04-29

    The present invention provides a biaxially textured laminate article having a polycrystalline biaxially textured metallic substrate with an electrically conductive oxide layer epitaxially deposited thereon and methods for producing same. In one embodiment a biaxially texture Ni substrate has a layer of LaNiO.sub.3 deposited thereon. An initial layer of electrically conductive oxide buffer is epitaxially deposited using a sputtering technique using a sputtering gas which is an inert or forming gas. A subsequent layer of an electrically conductive oxide layer is then epitaxially deposited onto the initial layer using a sputtering gas comprising oxygen. The present invention will enable the formation of biaxially textured devices which include HTS wires and interconnects, large area or long length ferromagnetic and/or ferroelectric memory devices, large area or long length, flexible light emitting semiconductors, ferroelectric tapes, and electrodes.

  19. Stereoselectivity in the oxidation of bufuralol, a chiral substrate, by human cytochrome P450s.

    PubMed

    Narimatsu, Shizuo; Takemi, Chie; Kuramoto, Shino; Tsuzuki, Daisuke; Hichiya, Hiroyuki; Tamagake, Keietsu; Yamamoto, Shigeo

    2003-05-01

    Bufuralol (BF), a nonselective beta-adrenoceptor blocking agent, has a chiral center in its molecule, yielding the enantiomers 1'R-BF and 1'S-BF. beta-Adrenoceptor blocking potency is much higher in 1'S-BF than in 1'R-BF. One of the metabolic pathways of BF is 1"-hydroxylation of an ethyl group attached at the aromatic 7-position forming a carbinol metabolite (1"-hydroxybufuralol, 1"-OH-BF), and further oxidation (or dehydrogenation) produces a ketone metabolite (1-oxobufuralol, 1"-Oxo-BF). Both 1"-OH-BF and 1"-Oxo-BF are known to have beta-adrenoceptor blocking activities comparable to or higher than those of the parent drug. The 1"-hydroxylation introduces another chiral center into the BF molecule and four 1"-OH-BF diastereomers are formed from BF racemate in mammals, including humans, making elucidation of the metabolic profiles complicated. HPLC methods employing derivatization, reversed phase, or chiral columns have been developed to efficiently separate the four 1"-OH-BF diastereomers formed from BF enantiomers or racemate. Accumulated in vitro experimental results revealed that 1'R-BF is a much more preferential substrate than 1'S-BR for BF 1"-hydroxylation in human liver microsomes. Kinetic studies using recombinant human cytochrome P450 (CYP) enzymes indicate that CYP2D6 serves as a major BF 1"-hydroxylase and that CYP1A2 and CYP2C19 also contribute to BF 1"-hydroxylation in human livers. This mini-review summarizes the knowledge reported so far on the pharmacology of BF and its metabolites and the profiles of BF metabolism, especially focusing on the stereoselectivity in the oxidation of BF mainly in human livers and recombinant CYP enzymes. PMID:12666241

  20. Rate-determining Attack on Substrate Precedes Rieske Cluster Oxidation during cis-Dihydroxylation by Benzoate Dioxygenase

    PubMed Central

    Rivard, Brent S.; Rogers, Melanie S.; Marell, Daniel J.; Neibergall, Matthew B.; Chakrabarty, Sarmistha; Cramer, Christopher J.; Lipscomb, John D.

    2015-01-01

    Rieske dearomatizing dioxygenases utilize a Rieske iron-sulfur cluster and a mononuclear Fe(II) located 15 Å across a subunit boundary to catalyze O2-dependent formation of cis-dihydrodiol products from aromatic substrates. During catalysis, O2 binds to the Fe(II) while the substrate bind nearby. Single turnover reactions have shown that one electron from each metal center is required for catalysis. This finding suggested that the reactive intermediate is Fe(III)-(H)peroxo or HO-Fe(V)=O formed by O-O bond scission. Surprisingly, several kinetic phases were observed during the single turnover Rieske cluster oxidation. Here, the Rieske cluster oxidation and product formation steps of a single turnover of benzoate 1,2-dioxygenase are investigated using benzoate and three fluorinated analogs. It is shown that the rate constant for product formation correlates with the reciprocal relaxation time of only the fastest kinetic phase (RRT-1) for each substrate, suggesting that the slower phases are not mechanistically relevant. RRT-1 is strongly dependent on substrate type, suggesting a role for substrate in electron transfer from the Rieske cluster to the mononuclear iron site. This insight, together with the substrate and O2 concentration dependencies of RRT-1, indicates that a reactive species is formed after substrate and O2 binding, but before electron transfer from the Rieske cluster. Computational studies show that RRT-1 is correlated with the electron density at the substrate carbon closest to the Fe(II), consistent with initial electrophilic attack by an Fe(III)-superoxo intermediate. The resulting Fe(III)-peroxo-aryl radical species would then readily accept an electron from the Rieske cluster to complete the cis-dihydroxylation reaction. PMID:26154836

  1. Laser Cladding to Improve Oxidation Behavior of Air Plasma-Sprayed Ni-20Cr Coating on Stainless Steel Substrate

    NASA Astrophysics Data System (ADS)

    Rauf, M. Mudassar; Shahid, Muhammad; Nusair Khan, A.; Mehmood, K.

    2015-09-01

    Air plasma-sprayed Ni-20Cr coating on stainless steel (AISI-304) substrate was re-melted using CO2 laser to remove the inherent defects, i.e., porosity, splat boundaries, and oxides of air plasma-sprayed coating. The (1) uncoated, (2) air plasma-sprayed, and (3) laser-re-melted specimens were exposed to cyclic oxidation at 900 °C for a hundred cycles run. The oxidation products were characterized using XRD and SEM. Weight changes were determined after every 4th cycle; Uncoated samples showed severe oxidation indicated by substantial weight loss, whereas air plasma-coated samples demonstrated noticeable weight gain. However, oxidation resistance of laser-cladded samples was found to be significantly improved as the samples showed negligible weight change; porosity within the coating was minimized with an improvement in interface quality causing reduction in delamination damage.

  2. Correlating the chemical composition and size of various metal oxide substrates with the catalytic activity and stability of as-deposited Pt nanoparticles for the methanol oxidation reaction

    SciTech Connect

    Megan E. Scofield; Wong, Stanislaus S.; Koenigsmann, Christopher; Bobb-Semple, Dara; Tao, Jing; Tong, Xiao; Wang, Lei; Lewis, Crystal S.; Vuklmirovic, Miomir; Zhu, Yimei; Adzic, Radoslav R.

    2015-12-09

    The performance of electrode materials in conventional direct alcohol fuel cells (DAFC) is constrained by (i) the low activity of the catalyst materials relative to their overall cost, (ii) the poisoning of the active sites due to the presence of partially oxidized carbon species (such as but not limited to CO, formate, and acetate) produced during small molecule oxidation, and (iii) the lack of catalytic stability and durability on the underlying commercial carbon support. Therefore, as a viable alternative, we have synthesized various metal oxide and perovskite materials of different sizes and chemical compositions as supports for Pt nanoparticles (NPs). Our results including unique mechanistic studies demonstrate that the SrRuO3 substrate with immobilized Pt NPs at its surface evinces the best methanol oxidation performance as compared with all of the other substrate materials tested herein, including commercial carbon itself. In addition, data from electron energy loss spectroscopy (EELS) and X-ray photoelectron spectroscopy (XPS) confirmed the presence of electron transfer from bound Pt NPs to surface Ru species within the SrRuO3 substrate itself, thereby suggesting that favorable metal support interactions are responsible for the increased methanol oxidation reaction (MOR) activity of Pt species with respect to the underlying SrRuO3 composite catalyst material.

  3. Correlating the chemical composition and size of various metal oxide substrates with the catalytic activity and stability of as-deposited Pt nanoparticles for the methanol oxidation reaction

    DOE PAGESBeta

    Megan E. Scofield; Wong, Stanislaus S.; Koenigsmann, Christopher; Bobb-Semple, Dara; Tao, Jing; Tong, Xiao; Wang, Lei; Lewis, Crystal S.; Vuklmirovic, Miomir; Zhu, Yimei; et al

    2015-12-09

    The performance of electrode materials in conventional direct alcohol fuel cells (DAFC) is constrained by (i) the low activity of the catalyst materials relative to their overall cost, (ii) the poisoning of the active sites due to the presence of partially oxidized carbon species (such as but not limited to CO, formate, and acetate) produced during small molecule oxidation, and (iii) the lack of catalytic stability and durability on the underlying commercial carbon support. Therefore, as a viable alternative, we have synthesized various metal oxide and perovskite materials of different sizes and chemical compositions as supports for Pt nanoparticles (NPs).more » Our results including unique mechanistic studies demonstrate that the SrRuO3 substrate with immobilized Pt NPs at its surface evinces the best methanol oxidation performance as compared with all of the other substrate materials tested herein, including commercial carbon itself. In addition, data from electron energy loss spectroscopy (EELS) and X-ray photoelectron spectroscopy (XPS) confirmed the presence of electron transfer from bound Pt NPs to surface Ru species within the SrRuO3 substrate itself, thereby suggesting that favorable metal support interactions are responsible for the increased methanol oxidation reaction (MOR) activity of Pt species with respect to the underlying SrRuO3 composite catalyst material.« less

  4. Xylo- and cello-oligosaccharide oxidation by gluco-oligosaccharide oxidase from Sarocladium strictum and variants with reduced substrate inhibition

    PubMed Central

    2013-01-01

    Background The oxidation of carbohydrates from lignocellulose can facilitate the synthesis of new biopolymers and biochemicals, and also reduce sugar metabolism by lignocellulolytic microorganisms, reserving aldonates for fermentation to biofuels. Although oxidoreductases that oxidize cellulosic hydrolysates have been well characterized, none have been reported to oxidize substituted or branched xylo-oligosaccharides. Moreover, this is the first report that identifies amino acid substitutions leading to GOOX variants with reduced substrate inhibition. Results The recombinant wild type gluco-oligosaccharide oxidase (GOOX) from the fungus Sarocladium strictum, along with variants that were generated by site-directed mutagenesis, retained the FAD cofactor, and showed high activity on cello-oligosaccharide and xylo-oligosaccharides, including substituted and branched xylo-oligosaccharides. Mass spectrometric analyses confirmed that GOOX introduces one oxygen atom to oxidized products, and 1H NMR and tandem mass spectrometry analysis confirmed that oxidation was restricted to the anomeric carbon. The A38V mutation, which is close to a predicted divalent ion-binding site in the FAD-binding domain of GOOX but 30 Å away from the active site, significantly increased the kcat and catalytic efficiency of the enzyme on all oligosaccharides. Eight amino acid substitutions were separately introduced to the substrate-binding domain of GOOX-VN (at positions Y72, E247, W351, Q353 and Q384). In all cases, the Km of the enzyme variant was higher than that of GOOX, supporting the role of corresponding residues in substrate binding. Most notably, W351A increased Km values by up to two orders of magnitude while also increasing kcat up to 3-fold on cello- and xylo-oligosaccharides and showing no substrate inhibition. Conclusions This study provides further evidence that S. strictum GOOX has broader substrate specificity than the enzyme name implies, and that substrate inhibition can be

  5. Compound semiconductor native oxide-based technologies for optical and electrical devices grown on gallium arsenide substrates using MOCVD

    NASA Astrophysics Data System (ADS)

    Holmes, Adrian Lawrence

    1999-11-01

    The beginning of the modern microelectronics industry can be traced back to an invention made in 1947 when Bardeen and Brattain created the first semiconductor switch, called a transistor. Several other important discoveries followed; however, two of the more significant were (i) the development of the first planar process using silicon dioxide (SiO2) as a mask for diffusions into silicon by Frosch in 1955, and (ii) the subsequent integration of several transistors in tiny circuits by Kilby in 1958. Due to the superior quality of the SiO2-silicon interface, Si-based metal-oxide-semiconductor (MOS) transistors have primarily been used in integrated circuits. Until recently, compound semiconductors did not have a native oxide of sufficient quality to create similar MOS transistors. In 1990, research performed by Professor Holonyak and his group at the University of Illinois at Urbana-Champaign has led to a high-quality, stable, and insulating native oxide created from aluminum-containing compound semiconductor alloys. This study investigates native oxide films that are formed by the thermal oxidation of AlAs and InAlP epitaxial layers grown lattice-matched on GaAs substrates using metalorganic chemical vapor deposition (MOCVD). The primary goal is to evaluate how these native oxides can help form novel device structures and transistors. To qualify the material properties of these native oxide films, we have used several characterization techniques including photoluminescence, cross-sectional scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Additionally, we have performed leakage current and capacitance-voltage measurements to evaluate the electrical characteristics of the native oxide-semiconductor interface. The kinetics of the thermal oxidation process for both the surface oxidation of InAlP and lateral oxidation of AlAs are studied and contrasted. Aided by this knowledge, we have created a sealed

  6. Uncouplers of mitochondrial oxidative phosphorylation are not substrates of the erythrocyte glutathione-S-conjugate pump.

    PubMed

    Sokal, A; Bartosz, G

    1998-01-01

    Uncouplers of mitochondrial oxidative phosphorylation, dinitrophenol (DNP) and carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP), were found to stimulate Mg(2+)-ATPase activity of human erythrocyte membranes in a manner competitive with respect to 2,4-dinitrophenyl-S-glutathione (DNP-SG) which suggested that these compounds may also be substrates of the glutathione-S-conjugate pump. We confirm that the stimulation of erythrocyte membrane ATPase activity by DNP and by another uncoupler, carbonyl cyanide m-chlorophenylhydrazone (CCCP), is competitive with respect to DNP-SG. However, we found no evidence for active transport of DNP and CCCP out of erythrocytes and demonstrate that they inhibit the low-affinity component of DNP-SG transport noncompetitively while stimulating the high-affinity DNP-SG transport (mediated by multidrug resistance-associated protein, MRP1). Implications of these findings may indicate the electrogenic nature of MRP1-mediated transport of glutathione-S conjugates and stimulation of aminophospholipid translocase (flippase) rather than the glutathione-S-conjugate pump by the uncouplers. PMID:9439589

  7. Optoelectrochemical biorecognition by optically transparent highly conductive graphene-modified fluorine-doped tin oxide substrates.

    PubMed

    Lamberti, F; Brigo, L; Favaro, M; Luni, C; Zoso, A; Cattelan, M; Agnoli, S; Brusatin, G; Granozzi, G; Giomo, M; Elvassore, N

    2014-12-24

    Both optical and electrochemical graphene-based sensors have gone through rapid development, reaching high sensitivity at low cost and with fast response time. However, the complex validating biochemical operations, needed for their consistent use, currently limits their effective application. We propose an integration strategy for optoelectrochemical detection that overcomes previous limitations of these sensors used separately. We develop an optoelectrochemical sensor for aptamer-mediated protein detection based on few-layer graphene immobilization on selectively modified fluorine-doped tin oxide (FTO) substrates. Our results show that the electrochemical properties of graphene-modified FTO samples are suitable for complex biological detection due to the stability and inertness of the engineered electrodic interface. In addition, few-layer immobilization of graphene sheets through electrostatic linkage with an electrochemically grafted FTO surface allows obtaining an optically accessible and highly conductive platform. As a proof of concept, we used insulin as the target molecule to reveal in solution. Because of its transparency and low sampling volume (a few microliters), our sensing unit can be easily integrated in lab-on-a-chip cell culture systems for effectively monitoring subnanomolar concentrations of proteins relevant for biomedical applications. PMID:25438087

  8. Transparent resistive switching memory using aluminum oxide on a flexible substrate

    NASA Astrophysics Data System (ADS)

    Yeom, Seung-Won; Shin, Sang-Chul; Kim, Tan-Young; Ha, Hyeon Jun; Lee, Yun-Hi; Shim, Jae Won; Ju, Byeong-Kwon

    2016-02-01

    Resistive switching memory (ReRAM) has attracted much attention in recent times owing to its fast switching, simple structure, and non-volatility. Flexible and transparent electronic devices have also attracted considerable attention. We therefore fabricated an Al2O3-based ReRAM with transparent indium-zinc-oxide (IZO) electrodes on a flexible substrate. The device transmittance was found to be higher than 80% in the visible region (400-800 nm). Bended states (radius = 10 mm) of the device also did not affect the memory performance because of the flexibility of the two transparent IZO electrodes and the thin Al2O3 layer. The conduction mechanism of the resistive switching of our device was explained by ohmic conduction and a Poole-Frenkel emission model. The conduction mechanism was proved by oxygen vacancies in the Al2O3 layer, as analyzed by x-ray photoelectron spectroscopy analysis. These results encourage the application of ReRAM in flexible and transparent electronic devices.

  9. Transparent resistive switching memory using aluminum oxide on a flexible substrate.

    PubMed

    Yeom, Seung-Won; Shin, Sang-Chul; Kim, Tan-Young; Ha, Hyeon Jun; Lee, Yun-Hi; Shim, Jae Won; Ju, Byeong-Kwon

    2016-02-19

    Resistive switching memory (ReRAM) has attracted much attention in recent times owing to its fast switching, simple structure, and non-volatility. Flexible and transparent electronic devices have also attracted considerable attention. We therefore fabricated an Al2O3-based ReRAM with transparent indium-zinc-oxide (IZO) electrodes on a flexible substrate. The device transmittance was found to be higher than 80% in the visible region (400-800 nm). Bended states (radius = 10 mm) of the device also did not affect the memory performance because of the flexibility of the two transparent IZO electrodes and the thin Al2O3 layer. The conduction mechanism of the resistive switching of our device was explained by ohmic conduction and a Poole-Frenkel emission model. The conduction mechanism was proved by oxygen vacancies in the Al2O3 layer, as analyzed by x-ray photoelectron spectroscopy analysis. These results encourage the application of ReRAM in flexible and transparent electronic devices. PMID:26763473

  10. Optical and Structural Properties of Europium Oxide Thin Films on Silicon Substrates

    NASA Astrophysics Data System (ADS)

    Bellocchi, Gabriele; Franzò, G.; Iacona, F.; Boninelli, S.; Miritello, M.; Terrasi, A.; Spinella, C.; Priolo, F.

    Europium-based materials are known for their intense and stable emission in the visible region. Moreover Eu is stable in both its divalent and trivalent oxidation states. In particular, emission of Eu2+ is much stronger, being allowed for electric dipole transition rules and is characterized by a broad peak, centered in the wavelength range 400-600 nm, while that of Eu3+ presents several sharp lines at around 600 nm. These peculiar optical properties make Eu-based systems an interesting material for photonic applications. The optical and structural properties of Eu2O3 thin films grown by RF magnetron sputtering on Si substrates have been studied. PL emission has been observed at room temperature and it is strongly dependent on the thermal process. In particular, annealing in O2 atmosphere leads to an enhancement of the Eu3+ emission, while films annealed in N2 ambient exhibit a very intense PL signal due to Eu2+. The chemical and structural characterization of the films, performed by TEM and XPS, reveals that a massive mixing at the Eu2O3-Si interface occurs in N2-annealed samples, leading to the formation of Eu (II) silicates, while in the case of O2-annealed samples we observe the formation of a SiOx layer at the interface, that minimize the diffusion of Si into the Eu2O3 layer.

  11. Substrate-dependent nitric oxide synthesis by secreted endoplasmic reticulum aminopeptidase 1 in macrophages.

    PubMed

    Goto, Yoshikuni; Ogawa, Kenji; Nakamura, Takahiro J; Hattori, Akira; Tsujimoto, Masafumi

    2015-06-01

    In this study, we examined the role of aminopeptidases with reference to endoplasmic reticulum aminopeptidase 1 (ERAP1) in nitric oxide (NO) synthesis employing murine macrophage cell line RAW264.7 cells activated by lipopolysaccharide (LPS) and interferon (IFN)-γ and LPS-activated peritoneal macrophages derived from ERAP1 knockout mouse. When NO synthesis was measured in the presence of peptides having N-terminal Arg, comparative NO synthesis was seen with that measured in the presence of Arg. In the presence of an aminopeptidase inhibitor amastatin, NO synthesis in activated RAW264.7 cells was significantly decreased. These results suggest that aminopeptidases are involved in the NO synthesis in activated RAW264.7 cells. Subsequently, significant reduction of NO synthesis was observed in ERAP1 knockdown cells compared with wild-type cells. This reduction was rescued by exogenously added ERAP1. Furthermore, when peritoneal macrophages prepared from ERAP1 knockout mouse were employed, reduction of NO synthesis in knockout mouse macrophages was also attributable to ERAP1. In the presence of amastatin, further reduction was observed in knockout mouse-derived macrophages. Taken together, these results suggest that several aminopeptidases play important roles in the maximum synthesis of NO in activated macrophages in a substrate peptide-dependent manner and ERAP1 is one of the aminopeptidases involved in the NO synthesis. PMID:25577645

  12. Oxidation and interdiffusion behavior of Niobium substrate coated MoSi2 coating prepared by spark plasma sintering

    NASA Astrophysics Data System (ADS)

    Yan, JianHui; Wang, Yi; Liu, LongFei; Wang, Yueming

    2014-11-01

    In order to protect Niobium material from oxidation, MoSi2 coating was prepared on the Niobium substrate by spark plasma sintering. Oxidation behavior of MoSi2 coating was investigated in air over the temperature range of 1200-1500 °C. The interfacial diffusion between MoSi2 coating and Niobium substrate was also examined. Dense MoSi2 coating was successfully prepared using spark plasma sintering. The porosities of top and side coatings are about 5.5% and 6.4%, respectively. No cracks were present in the MoSi2 coating. Cracking and spallation of the SiO2 scale did not occur at test temperatures. Two intermediate phases-(Nb,Mo)5Si3 and Nb5Si3 phases, were detected in the boundary of MoSi2 coating and Nb substrate. The growth of the reaction layer was dominated by the diffusion of Si toward the Nb substrate and obeyed a parabolic rate law. A multi-layered structural coating formed on Nb substrate, which consisted of MoSi2, (Mo,Nb)5Si3 and Nb5Si3 in turn.

  13. Probing the structural dependency of photoinduced properties of colloidal quantum dots using metal-oxide photo-active substrates

    SciTech Connect

    Patty, Kira; Campbell, Quinn; Hamilton, Nathan; West, Robert G.; Sadeghi, Seyed M.; Mao, Chuanbin

    2014-09-21

    We used photoactive substrates consisting of about 1 nm coating of a metal oxide on glass substrates to investigate the impact of the structures of colloidal quantum dots on their photophysical and photochemical properties. We showed during irradiation these substrates can interact uniquely with such quantum dots, inducing distinct forms of photo-induced processes when they have different cores, shells, or ligands. In particular, our results showed that for certain types of core-shell quantum dot structures an ultrathin layer of a metal oxide can reduce suppression of quantum efficiency of the quantum dots happening when they undergo extensive photo-oxidation. This suggests the possibility of shrinking the sizes of quantum dots without significant enhancement of their non-radiative decay rates. We show that such quantum dots are not influenced significantly by Coulomb blockade or photoionization, while those without a shell can undergo a large amount of photo-induced fluorescence enhancement via such blockade when they are in touch with the metal oxide.

  14. Large-area alignment of tungsten oxide nanowires over flat and patterned substrates for room-temperature gas sensing.

    PubMed

    Cheng, Wei; Ju, Yanrui; Payamyar, Payam; Primc, Darinka; Rao, Jingyi; Willa, Christoph; Koziej, Dorota; Niederberger, Markus

    2015-01-01

    Alignment of nanowires over a large area of flat and patterned substrates is a prerequisite to use their collective properties in devices such as gas sensors. In this work, uniform single-crystalline ultrathin W18 O49 nanowires with diameters less than 2 nm and aspect ratios larger than 100 have been synthesized, and, despite their flexibility, assembled into thin films with high orientational order over a macroscopic area by the Langmuir-Blodgett technique. Alignment of the tungsten oxide nanowires was also possible on top of sensor substrates equipped with electrodes. Such sensor devices were found to exhibit outstanding sensitivity to H2 at room temperature. PMID:25412600

  15. Appetitive Aggression in Women: Comparing Male and Female War Combatants

    PubMed Central

    Meyer-Parlapanis, Danie; Weierstall, Roland; Nandi, Corina; Bambonyé, Manassé; Elbert, Thomas; Crombach, Anselm

    2016-01-01

    Appetitive aggression refers to positive feelings being associated with the perpetration of violent behavior and has been shown to provide resilience against the development of PTSD in combatants returning from the battlefield. Until this point, appetitive aggression has been primarily researched in males. This study investigates appetitive aggression in females. Female and male combatants and civilians from Burundi were assessed for levels of appetitive aggression. In contrast to non-combatants, no sex difference in appetitive aggression could be detected for combatants. Furthermore, each of the female and male combatant groups displayed substantially higher levels of appetitive aggression than each of the male and female civilian control groups. This study demonstrates that in violent contexts, such as armed conflict, in which individuals perpetrate numerous aggressive acts against others, the likelihood for an experience of appetitive aggression increases- regardless of whether the individuals are male or female. PMID:26779084

  16. Appetitive Aggression in Women: Comparing Male and Female War Combatants.

    PubMed

    Meyer-Parlapanis, Danie; Weierstall, Roland; Nandi, Corina; Bambonyé, Manassé; Elbert, Thomas; Crombach, Anselm

    2015-01-01

    Appetitive aggression refers to positive feelings being associated with the perpetration of violent behavior and has been shown to provide resilience against the development of PTSD in combatants returning from the battlefield. Until this point, appetitive aggression has been primarily researched in males. This study investigates appetitive aggression in females. Female and male combatants and civilians from Burundi were assessed for levels of appetitive aggression. In contrast to non-combatants, no sex difference in appetitive aggression could be detected for combatants. Furthermore, each of the female and male combatant groups displayed substantially higher levels of appetitive aggression than each of the male and female civilian control groups. This study demonstrates that in violent contexts, such as armed conflict, in which individuals perpetrate numerous aggressive acts against others, the likelihood for an experience of appetitive aggression increases- regardless of whether the individuals are male or female. PMID:26779084

  17. Nd:YVO4 laser direct ablation of indium tin oxide films deposited on glass and polyethylene terephthalate substrates.

    PubMed

    Wang, Jian-Xun; Kwon, Sang Jik; Han, Jae-Hee; Cho, Eou Sik

    2013-09-01

    A Q-switched diode-pumped neodymium-doped yttrium vanadate (Nd:YVO4, lambda = 1064 nm) laser was applied to obtain the indium tin oxide (ITO) patterns on flexible polyethylene terephthalate (PET) substrate by a direct etching method. After the ITO films were deposited on a soda-lime glass and PET substrate, laser ablations were carried out on the ITO films for various conditions and the laser ablated results on the ITO films were investigated and analyzed considering the effects of substrates on the laser etching. The laser ablated widths on ITO deposited on glass were found to be much narrower than those on ITO deposited on PET substrate, especially, at a higher scanning speed of laser beam such as 1000 mm/s and 2000 mm/s. As the thermal conductivity of glass substrate is about 7.5 times higher than that of PET, more thermal energy would be spread and transferred to lateral direction in the ITO film in case of PET substrate. PMID:24205645

  18. Plasma surface oxidation of 316L stainless steel for improving adhesion strength of silicone rubber coating to metal substrate

    NASA Astrophysics Data System (ADS)

    Latifi, Afrooz; Imani, Mohammad; Khorasani, Mohammad Taghi; Daliri Joupari, Morteza

    2014-11-01

    Stainless steel 316L is one of the most widely used materials for fabricating of biomedical devices hence, improving its surface properties is still of great interest and challenging in biomaterial sciences. Plasma oxidation, in comparison to the conventional chemical or mechanical methods, is one of the most efficient methods recently used for surface treatment of biomaterials. Here, stainless steel specimens were surface oxidized by radio-frequency plasma irradiation operating at 34 MHz under pure oxygen atmosphere. Surface chemical composition of the samples was significantly changed after plasma oxidation by appearance of the chromium and iron oxides on the plasma-oxidized surface. A wettable surface, possessing high surface energy (83.19 mN m-1), was observed after plasma oxidation. Upon completion of the surface modification process, silicone rubber was spray coated on the plasma-treated stainless steel surface. Morphology of the silicone rubber coating was investigated by scanning electron microscopy (SEM). A uniform coating was formed on the oxidized surface with no delamination at polymer-metal interface. Pull-off tests showed the lowest adhesion strength of coating to substrate (0.12 MPa) for untreated specimens and the highest (0.89 MPa) for plasma-oxidized ones.

  19. Composite plasma electrolytic oxidation to improve the thermal radiation performance and corrosion resistance on an Al substrate

    NASA Astrophysics Data System (ADS)

    Kim, Donghyun; Sung, Dahye; Lee, Junghoon; Kim, Yonghwan; Chung, Wonsub

    2015-12-01

    A composite plasma electrolytic oxidation (PEO) was performed for enhancing the thermal radiation performance and corrosion resistance on an Al alloy by dispersing cupric oxide (CuO) particles in a conventional PEO electrolyte. Cu-based oxides (CuO and Cu2O) formed by composite PEO increased the emissivity of the substrate to 0.892, and made the surface being dark color, similar to a black body, i.e., an ideal radiator. In addition, the corrosion resistance was analyzed using potentio-dynamic polarization and electrochemical impedance spectroscopy tests in 3.5 wt.% NaCl aqueous solution. An optimum condition of 10 ampere per square decimeter (ASD) current density and 30 min processing time produced appropriate surface morphologies and coating thicknesses, as well as dense Cu- and Al-based oxides that constituted the coating layers.

  20. Growth of light-emitting SiGe heterostructures on strained silicon-on-insulator substrates with a thin oxide layer

    SciTech Connect

    Baidakova, N. A.; Bobrov, A. I.; Drozdov, M. N.; Novikov, A. V.; Pavlov, D. A.; Shaleev, M. V.; Yunin, P. A.; Yurasov, D. V.; Krasilnik, Z. F.

    2015-08-15

    The possibility of using substrates based on “strained silicon on insulator” structures with a thin (25 nm) buried oxide layer for the growth of light-emitting SiGe structures is studied. It is shown that, in contrast to “strained silicon on insulator” substrates with a thick (hundreds of nanometers) oxide layer, the temperature stability of substrates with a thin oxide is much lower. Methods for the chemical and thermal cleaning of the surface of such substrates, which make it possible to both retain the elastic stresses in the thin Si layer on the oxide and provide cleaning of the surface from contaminating impurities, are perfecte. It is demonstrated that it is possible to use the method of molecular-beam epitaxy to grow light-emitting SiGe structures of high crystalline quality on such substrates.

  1. Network of hypothalamic neurons that control appetite

    PubMed Central

    Sohn, Jong-Woo

    2015-01-01

    The central nervous system (CNS) controls food intake and energy expenditure via tight coordinations between multiple neuronal populations. Specifically, two distinct neuronal populations exist in the arcuate nucleus of hypothalamus (ARH): the anorexigenic (appetite-suppressing) pro-opiomelanocortin (POMC) neurons and the orexigenic (appetite-increasing) neuropeptide Y (NPY)/agouti-related peptide (AgRP) neurons. The coordinated regulation of neuronal circuit involving these neurons is essential in properly maintaining energy balance, and any disturbance therein may result in hyperphagia/obesity or hypophagia/starvation. Thus, adequate knowledge of the POMC and NPY/AgRP neuron physiology is mandatory to understand the pathophysiology of obesity and related metabolic diseases. This review will discuss the history and recent updates on the POMC and NPY/AgRP neuronal circuits, as well as the general anorexigenic and orexigenic circuits in the CNS. [BMB Reports 2015; 48(4): 229-233] PMID:25560696

  2. Ex Vivo Antioxidant Activity of Selected Medicinal Plants against Fenton Reaction-Mediated Oxidation of Biological Lipid Substrates

    PubMed Central

    Pai Kotebagilu, Namratha; Reddy Palvai, Vanitha; Urooj, Asna

    2015-01-01

    Free radical-mediated oxidation is often linked to various degenerative diseases. Biological substrates with lipids as major components are susceptible to oxygen-derived lipid peroxidation due to their composition. Lipid peroxide products act as biomarkers in evaluating the antioxidant potential of various plants and functional foods. The study focused on evaluation of the antioxidant potential of two extracts (methanol and 80% methanol) of four medicinal plants, Andrographis paniculata, Costus speciosus, Canthium parviflorum, and Abrus precatorius, against Fenton reaction-mediated oxidation of three biological lipid substrates; cholesterol, low-density lipoprotein, and brain homogenate. The antioxidant activity of the extracts was measured by thiobarbituric acid reactive substances method. Also, the correlation between the polyphenol, flavonoid content, and the antioxidant activity in biological substrates was analyzed. Results indicated highest antioxidant potential by 80% methanol extract of Canthium parviflorum (97.55%), methanol extract of Andrographis paniculata (72.15%), and methanol extract of Canthium parviflorum (49.55%) in cholesterol, low-density lipoprotein, and brain, respectively. The polyphenol and flavonoid contents of methanol extract of Andrographis paniculata in cholesterol (r = 0.816) and low-density lipoprotein (r = 0.948) and Costus speciosus in brain (r = 0.977, polyphenols, and r = 0.949, flavonoids) correlated well with the antioxidant activity. The findings prove the antioxidant potential of the selected medicinal plants against Fenton reaction in biological lipid substrates. PMID:26933511

  3. Ex Vivo Antioxidant Activity of Selected Medicinal Plants against Fenton Reaction-Mediated Oxidation of Biological Lipid Substrates.

    PubMed

    Pai Kotebagilu, Namratha; Reddy Palvai, Vanitha; Urooj, Asna

    2015-01-01

    Free radical-mediated oxidation is often linked to various degenerative diseases. Biological substrates with lipids as major components are susceptible to oxygen-derived lipid peroxidation due to their composition. Lipid peroxide products act as biomarkers in evaluating the antioxidant potential of various plants and functional foods. The study focused on evaluation of the antioxidant potential of two extracts (methanol and 80% methanol) of four medicinal plants, Andrographis paniculata, Costus speciosus, Canthium parviflorum, and Abrus precatorius, against Fenton reaction-mediated oxidation of three biological lipid substrates; cholesterol, low-density lipoprotein, and brain homogenate. The antioxidant activity of the extracts was measured by thiobarbituric acid reactive substances method. Also, the correlation between the polyphenol, flavonoid content, and the antioxidant activity in biological substrates was analyzed. Results indicated highest antioxidant potential by 80% methanol extract of Canthium parviflorum (97.55%), methanol extract of Andrographis paniculata (72.15%), and methanol extract of Canthium parviflorum (49.55%) in cholesterol, low-density lipoprotein, and brain, respectively. The polyphenol and flavonoid contents of methanol extract of Andrographis paniculata in cholesterol (r = 0.816) and low-density lipoprotein (r = 0.948) and Costus speciosus in brain (r = 0.977, polyphenols, and r = 0.949, flavonoids) correlated well with the antioxidant activity. The findings prove the antioxidant potential of the selected medicinal plants against Fenton reaction in biological lipid substrates. PMID:26933511

  4. Latina mothers' influences on child appetite regulation.

    PubMed

    Silva Garcia, Karina; Power, Thomas G; Fisher, Jennifer Orlet; O'Connor, Teresia M; Hughes, Sheryl O

    2016-08-01

    Parents influence child weight through interactions that shape the development of child eating behaviors. In this study we examined the association between maternal autonomy promoting serving practices and child appetite regulation. We predicted that maternal autonomy promoting serving practices would be positively associated with child appetite regulation. Participants were low-income Latino children-a group at high risk for the development of childhood obesity. A total of 186 low-income Latina mothers and their 4-5 year old children came to a laboratory on two separate days. On the first day, mothers and children chose foods for a meal from a buffet and were audio/videotaped so that maternal autonomy promoting serving practices could be later coded. On the second day, children completed the Eating in the Absence of Hunger (EAH) task to measure child appetite regulation. Mothers also completed the Child Eating Behavior Questionnaire (CEBQ) to measure other aspects of child appetite regulation (food responsiveness, satiety responsiveness, and emotional overeating). Maternal autonomy promotion during serving was assessed using seven separate measures of child and maternal behavior. Principal components analyses of these serving measures yielded three components: allows child choice, child serves food, and mother does not restrict. Consistent with hypotheses, maternal autonomy promoting serving practices (i.e., allows child choice and does not restrict) were negatively associated with maternal reports of child food responsiveness and emotional overeating (CEBQ). The results for the EAH task were more complex-mothers who were autonomy promoting in their serving practices had children who ate the most in the absence of hunger, but this linear effect was moderated somewhat by a quadratic effect, with moderate levels of autonomy promotion during serving associated with the greatest child EAH. PMID:27083128

  5. Oxidations of Organic and Inorganic Substrates by Superoxo-, hydroperoxo-, and oxo-compounds of the transition metals.

    SciTech Connect

    Michael John Vasbinder

    2006-12-12

    Hammett correlation. It was found that the values of the Hammett reaction constant PN were -1.0(1) for 4-nitro-2-methylpyridine-N-oxide and -2.6(4) for 4-methylpyridine-N-oxide as substrates. The negative value confirms pyridine is acting as a nucleophile. Nucleophiles other than pyridine derivatives were also tested. In the end, it was found that the most effective nucleophiles were the pyridine-N-oxides themselves, meaning that a second equivalent of substrate serves as the most efficient promoter of this oxygen-atom transfer reaction. This relative nucleophilicity of pyridines and pyridine-N-oxides is similar to what is observed in other OAT reactions generating high-valent metal-oxo species.

  6. Method for Fabricating Textured High-Haze ZnO:Al Transparent Conduction Oxide Films on Chemically Etched Glass Substrates.

    PubMed

    Park, Hyeongsik; Nam, Sang-Hun; Shin, Myunghun; Ju, Minkyu; Lee, Youn-Jung; Yu, Jung-Hoon; Jung, Junhee; Kim, Sunbo; Ahn, Shihyun; Boo, Jin-Hyo; Yi, Junsin

    2016-05-01

    We developed a technique for forming textured aluminum-doped zinc oxide (ZnO:Al) transparent conductive oxide (TCO) films on glass substrates, which were etched using a mixture of hydrofluoric (HF) and hydrochloric (HCl) acids. The etching depth and surface roughness increased with an increase in the HF content and the etching time. The HF-based residues produced insoluble hexafluorosilicate anion- and oxide impurity-based semipermeable films, which reduced the etching rate. Using a small amount of HCl dissolved the Ca compounds, helping to fragment the semipermeable film. This formed random, complex structures on the glass substrates. The angled deposition of three layers of ZnO:Al led to the synthesis of multiscaled ZnO:Al textures on the glass substrates. The proposed approach resulted in textured ZnO:Al TCO films that exhibited high transmittance (-80%) and high haze (> 40%) values over wavelengths of 400-1000 nm, as well as low sheet resistances (< 18 Ω/sq)..Si tandem solar cells based on the ZnO:Al textured TCO films exhibited photocurrents and cell efficiencies that were 40% higher than those of cells with conventional TCO films. PMID:27483840

  7. Multi-laminated copper nanoparticles deposited on conductive substrates for electrocatalytic oxidation of methanol in alkaline electrolytes

    NASA Astrophysics Data System (ADS)

    Xia, Lun-Peng; Guo, Peng; Wang, Yan; Ding, Shi-Qi; He, Jian-Bo

    2014-09-01

    A simple electrodeposition approach to grow multi-laminated copper particles on two conductive substrates is presented. Morphological and structural characterization was performed using SEM and XRD. The copper crystallites are preferentially oriented with {111} planes parallel to the substrate surfaces, providing an optimum interface for methanol oxidation. There are a large number of edges, corners, and atomic steps around individual multi-laminated nanostructured particles. The excellent electrocatalytic activity of the particles to methanol oxidation in alkaline solutions is demonstrated by cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry. The presence of the conductive poly(2-amino-5-mercapto-1,3,4-thiadiazole) interlayer between the Cu particles and the carbon paste substrate results in larger specific surface areas of the particles and smaller charge-transfer resistances of methanol oxidation reaction in the lower potential range. Such an anisotropic laminated structure of non-noble metal nanomaterials deserves further investigation for finding a suitable alternative to noble metal-based anodic catalysts in fuel cells.

  8. Stimulants for the Control of Hedonic Appetite

    PubMed Central

    Poulton, Alison S.; Hibbert, Emily J.; Champion, Bernard L.; Nanan, Ralph K. H.

    2016-01-01

    The focus of this paper is treatment of obesity in relation to the management of hedonic appetite. Obesity is a complex condition which may be potentiated by excessive reward seeking in combination with executive functioning deficits that impair cognitive control of behavior. Stimulant medications address both reward deficiency and enhance motivation, as well as suppressing appetite. They have long been recognized to be effective for treating obesity. However, stimulants can be abused for their euphoric effect. They induce euphoria via the same neural pathway that underlies their therapeutic effect in obesity. For this reason they have generally not been endorsed for use in obesity. Among the stimulants, only phentermine (either alone or in combination with topiramate) and bupropion (which has stimulant-like properties and is used in combination with naltrexone), are approved by the United States Food and Drug Administration (FDA) for obesity, although dexamphetamine and methylpenidate are approved and widely used for treating attention deficit hyperactivity disorder (ADHD) in adults and children. Experience gained over many years in the treatment of ADHD demonstrates that with careful dose titration, stimulants can be used safely. In obesity, improvement in mood and executive functioning could assist with the lifestyle changes necessary for weight control, acting synergistically with appetite suppression. The obesity crisis has reached the stage that strong consideration should be given to adequate utilization of this effective and inexpensive class of drug. PMID:27199749

  9. Stimulants for the Control of Hedonic Appetite.

    PubMed

    Poulton, Alison S; Hibbert, Emily J; Champion, Bernard L; Nanan, Ralph K H

    2016-01-01

    The focus of this paper is treatment of obesity in relation to the management of hedonic appetite. Obesity is a complex condition which may be potentiated by excessive reward seeking in combination with executive functioning deficits that impair cognitive control of behavior. Stimulant medications address both reward deficiency and enhance motivation, as well as suppressing appetite. They have long been recognized to be effective for treating obesity. However, stimulants can be abused for their euphoric effect. They induce euphoria via the same neural pathway that underlies their therapeutic effect in obesity. For this reason they have generally not been endorsed for use in obesity. Among the stimulants, only phentermine (either alone or in combination with topiramate) and bupropion (which has stimulant-like properties and is used in combination with naltrexone), are approved by the United States Food and Drug Administration (FDA) for obesity, although dexamphetamine and methylpenidate are approved and widely used for treating attention deficit hyperactivity disorder (ADHD) in adults and children. Experience gained over many years in the treatment of ADHD demonstrates that with careful dose titration, stimulants can be used safely. In obesity, improvement in mood and executive functioning could assist with the lifestyle changes necessary for weight control, acting synergistically with appetite suppression. The obesity crisis has reached the stage that strong consideration should be given to adequate utilization of this effective and inexpensive class of drug. PMID:27199749

  10. Generic process for preparing a crystalline oxide upon a group IV semiconductor substrate

    DOEpatents

    McKee, Rodney A.; Walker, Frederick J.; Chisholm, Matthew F.

    2000-01-01

    A process for growing a crystalline oxide epitaxially upon the surface of a Group IV semiconductor, as well as a structure constructed by the process, is described. The semiconductor can be germanium or silicon, and the crystalline oxide can generally be represented by the formula (AO).sub.n (A'BO.sub.3).sub.m in which "n" and "m" are non-negative integer repeats of planes of the alkaline earth oxides or the alkaline earth-containing perovskite oxides. With atomic level control of interfacial thermodynamics in a multicomponent semiconductor/oxide system, a highly perfect interface between a semiconductor and a crystalline oxide can be obtained.

  11. Superhydrophobic SERS Substrates Based on Silver-Coated Reduced Graphene Oxide Gratings Prepared by Two-Beam Laser Interference.

    PubMed

    Yan, Zhao-Xu; Zhang, Yong-Lai; Wang, Wei; Fu, Xiu-Yan; Jiang, Hao-Bo; Liu, Yu-Qing; Verma, Prabhat; Kawata, Satoshi; Sun, Hong-Bo

    2015-12-16

    Reported here is the fabrication of reduced graphene oxide (RGO) grating structures by two-beam laser interference (TBLI) for the development of highly efficient SERS substrates via simple physical vapor deposition (PVD) coating of silver. TBLI has been utilized to make hierarchical RGO grating structures with microscale gratings and nanoscale folders through a laser treatment induced ablation and photoreduction process. The hierarchical structures contribute to the formation of plasmonic structures after silver coating, giving rise to the formation of plenty of SERS "hot spots", while the RGO substrate would provide chemical enhancement of Raman signal through interaction with analytes molecules. The significantly increased roughness with respect to the hierarchical structures in combination with the removal of hydrophilic oxygen-containing groups endow the resultant substrates with unique superhydrophobicity, which leads to the enrichment of analytes and further lowers the detection limit. The synergistic effects make the silver coated RGO gratings a highly efficient SERS substrate; in the detection of Rhodamine B, our SERS substrates showed high SERS enhancement and good reproducibility, a detection limit of 10(-10) M has been achieved. PMID:26595745

  12. Growth of tin oxide thin films composed of nanoparticles on hydrophilic and hydrophobic glass substrates by spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Paloly, Abdul Rasheed; Satheesh, M.; Martínez-Tomás, M. Carmen; Muñoz-Sanjosé, Vicente; Rajappan Achary, Sreekumar; Bushiri, M. Junaid

    2015-12-01

    In this paper, we have demonstrated the growth of tin oxide (SnO2) thin films composed of nanoparticles on hydrophobic (siliconized) and hydrophilic (non-siliconized) glass substrates by using the spray pyrolysis technique. X-ray diffraction (XRD) analysis confirmed the formation of SnO2 thin films with tetragonal rutile-phase structure. Average particle size of nanoparticles was determined to be in the range of 3-4 nm measured from the front view images obtained by a field emission gun scanning electron microscope (FESEM), while the size of nanoparticle clusters, when present, were in the range of 11-20 nm. Surface morphology of SnO2 films grown over hydrophobic substrates revealed larger isolated particles which are less crowded compared to the highly crowded and agglomerated smaller particles in films on hydrophilic substrates. Blue shift in the band gap is observed in samples in which the average particle size is slightly larger than the exciton Bohr radius. Photoluminescence (PL) analysis of samples grown over hydrophobic substrates exhibited an intense defect level emission and a weak near band edge emission. The enhanced visible emission from these SnO2 thin films is attributed to lattice defects formed during the film growth due to the mismatch between the film and the hydrophobic substrate surface.

  13. Hypothalamic metabolic compartmentation during appetite regulation as revealed by magnetic resonance imaging and spectroscopy methods

    PubMed Central

    Lizarbe, Blanca; Benitez, Ania; Peláez Brioso, Gerardo A.; Sánchez-Montañés, Manuel; López-Larrubia, Pilar; Ballesteros, Paloma; Cerdán, Sebastián

    2013-01-01

    We review the role of neuroglial compartmentation and transcellular neurotransmitter cycling during hypothalamic appetite regulation as detected by Magnetic Resonance Imaging (MRI) and Spectroscopy (MRS) methods. We address first the neurochemical basis of neuroendocrine regulation in the hypothalamus and the orexigenic and anorexigenic feed-back loops that control appetite. Then we examine the main MRI and MRS strategies that have been used to investigate appetite regulation. Manganese-enhanced magnetic resonance imaging (MEMRI), Blood oxygenation level-dependent contrast (BOLD), and Diffusion-weighted magnetic resonance imaging (DWI) have revealed Mn2+ accumulations, augmented oxygen consumptions, and astrocytic swelling in the hypothalamus under fasting conditions, respectively. High field 1H magnetic resonance in vivo, showed increased hypothalamic myo-inositol concentrations as compared to other cerebral structures. 1H and 13C high resolution magic angle spinning (HRMAS) revealed increased neuroglial oxidative and glycolytic metabolism, as well as increased hypothalamic glutamatergic and GABAergic neurotransmissions under orexigenic stimulation. We propose here an integrative interpretation of all these findings suggesting that the neuroendocrine regulation of appetite is supported by important ionic and metabolic transcellular fluxes which begin at the tripartite orexigenic clefts and become extended spatially in the hypothalamus through astrocytic networks becoming eventually MRI and MRS detectable. PMID:23781199

  14. A colorimetric sensor based on anodized aluminum oxide (AAO) substrate for the detection of nitroaromatics.

    SciTech Connect

    Liu, Y.; Wang, H. H.; Indacochea, J. E.; Wang, M. L.

    2011-12-15

    Simple and low cost colorimetric sensors for explosives detection were explored and developed. Anodized aluminum oxide (AAO) with large surface area through its porous structure and light background color was utilized as the substrate for colorimetric sensors. Fabricated thin AAO films with thickness less than {approx} 500 nm allowed us to observe interference colors which were used as the background color for colorimetric detection. AAO thin films with various thickness and pore-to-pore distance were prepared through anodizing aluminum foils at different voltages and times in dilute sulfuric acid. Various interference colors were observed on these samples due to their difference in structures. Accordingly, suitable anodization conditions that produce AAO samples with desired light background colors for optical applications were obtained. Thin film interference model was applied to analyze the UV-vis reflectance spectra and to estimate the thickness of the AAO membranes. We found that the thickness of produced AAO films increased linearly with anodization time in sulfuric acid. In addition, the growth rate was higher for AAO anodized using higher voltages. The thin film interference formulism was further validated with a well established layer by layer deposition technique. Coating poly(styrene sulfonate) sodium salt (PSS) and poly(allylamine hydrochloride) (PAH) layer by layer on AAO thin film consistently shifted its surface color toward red due to the increase in thickness. The red shift of UV-vis reflectance was correlated quantitatively to the number of layers been assembled. This sensitive red shift due to molecular attachment (increase in thickness) on AAO substrate was applied toward nitroaromatics detection. Aminopropyltrimethoxysilane (APTS) which can be attached onto AAO nanowells covalently through silanization and attract TNT molecules was coated and applied for TNT detection. UV-vis spectra of AAO with APTS shifted to the longer wavelength side due to

  15. Development and Comparison of the Substrate Scope of Pd-Catalysts for the Aerobic Oxidation of Alcohols

    PubMed Central

    Schultz, Mitchell J.; Hamilton, Steven S.; Jensen, David R.; Sigman, Matthew S.

    2009-01-01

    Three catalysts for aerobic oxidation of alcohols are discussed and the effectiveness of each is evaluated for allylic, benzylic, aliphatic, and functionalized alcohols. Additionally, chiral nonracemic substrates as well as chemoselective and diastereoselective oxidations are investigated. In this study, the most convenient system for the Pd-catalyzed aerobic oxidation of alcohols is Pd(OAc)2 in combination with triethylamine. This system functions effectively for the majority of alcohols tested and uses mild conditions (3 to 5 mol % of catalyst, room temperature). Pd(IiPr)(OAc)2(H2O) (1) also successfully oxidizes the majority of alcohols evaluated. This system has the advantage of significantly lowering catalyst loadings but requires higher temperatures (0.1 to 1 mol % of catalyst, 60 °C). A new catalyst is also disclosed, Pd(IiPr)(OPiv)2 (2). This catalyst operates under very mild conditions (1 mol %, room temperature, and air as the O2 source) but with a more limited substrate scope. PMID:15844968

  16. Synthesis of gallium nitride nanostructures by nitridation of electrochemically deposited gallium oxide on silicon substrate

    PubMed Central

    2014-01-01

    Gallium nitride (GaN) nanostructures were successfully synthesized by the nitridation of the electrochemically deposited gallium oxide (Ga2O3) through the utilization of a so-called ammoniating process. Ga2O3 nanostructures were firstly deposited on Si substrate by a simple two-terminal electrochemical technique at a constant current density of 0.15 A/cm2 using a mixture of Ga2O3, HCl, NH4OH and H2O for 2 h. Then, the deposited Ga2O3 sample was ammoniated in a horizontal quartz tube single zone furnace at various ammoniating times and temperatures. The complete nitridation of Ga2O3 nanostructures at temperatures of 850°C and below was not observed even the ammoniating time was kept up to 45 min. After the ammoniating process at temperature of 900°C for 15 min, several prominent diffraction peaks correspond to hexagonal GaN (h-GaN) planes were detected, while no diffraction peak of Ga2O3 structure was detected, suggesting a complete transformation of Ga2O3 to GaN. Thus, temperature seems to be a key parameter in a nitridation process where the deoxidization rate of Ga2O3 to generate gaseous Ga2O increase with temperature. The growth mechanism for the transformation of Ga2O3 to GaN was proposed and discussed. It was found that a complete transformation can not be realized without a complete deoxidization of Ga2O3. A significant change of morphological structures takes place after a complete transformation of Ga2O3 to GaN where the original nanorod structures of Ga2O3 diminish, and a new nanowire-like GaN structures appear. These results show that the presented method seems to be promising in producing high-quality h-GaN nanostructures on Si. PMID:25593562

  17. Catalytic transformations of biomass substrates using mixed metal oxides derived from substituted hydrotalcites

    NASA Astrophysics Data System (ADS)

    Macala, Gerald Stephen, II

    Fueled by seemingly endless reserves of cheap and easily accessible fossil energy, the industrial age has brought to the developed world tremendous advances in human health and well being. Unfortunately the burning of fossil fuels has also been implicated in increasing atmospheric CO2 concentrations and global climate change. Concerns about short-term and long-term supply further build a case for the need for alternative energy sources. Biomass derived materials are a tantalizing source of fuels and fine chemicals. Unlike petroleum derived hydrocarbons, biomass can be both renewable and carbon neutral. Crops can be regenerated annually or even more often in tropical climates, and since the captured carbon originates as atmospheric CO2, the overall cycle has the potential to be nearly carbon neutral regardless of the final fate of the carbon. In contrast to petroleum derived hydrocarbons, which can often be made more valuable by adding functionality, biomass derived materials are already highly functionalized and can usually be made more valuable by selective removal of functionality. The development of robust catalysts capable of selective defuntionalization of biomass derived substrates remains an important challenge with potentially enormous economic and societal impact. In addition to being robust and selective, catalysts should preferably be heterogeneous to allow for easier removal and regeneration after the reaction is complete. New materials consisting of Mg-Al hydrotalcite-like structures, with a limiting percentage of Mg or Al substituted with other M2+ or M3+ cations, were synthesized by a co-precipitation process in basic aqueous solution with carbonate as counterion. Calcination of these materials at 460 °C resulted in evolution of CO2 and water and yielded high surface area mixed metal oxides with enhanced reactivity. Materials were characterized by ICP for elemental analysis, XRD for structural information, XPS for surface elemental analysis and TEM

  18. Method For Improving The Oxidation Resistance Of Metal Substrates Coated With Thermal Barrier Coatings

    DOEpatents

    Thompson, Anthony Mark; Gray, Dennis Michael; Jackson, Melvin Robert

    2003-05-13

    A method for providing a protective coating on a metal-based substrate is disclosed. The method involves the application of an aluminum-rich mixture to the substrate to form a discontinuous layer of aluminum-rich particles, followed by the application of a second coating over the discontinuous layer of aluminum-rich particles. Aluminum diffuses from the aluminum-rich layer into the substrate, and into any bond coat layer which is subsequently applied. Related articles are also described. A method for providing a protective coating on a metal-based substrate is disclosed. The method involves the application of an aluminum-rich mixture to the substrate to form a discontinuous layer of aluminum-rich particles, followed by the application of a second coating over the discontinuous layer of aluminum-rich particles. Aluminum diffuses from the aluminum-rich layer into the substrate, and into any bond coat layer which is subsequently applied. Related articles are also described.

  19. Identification of Novel in vivo MAP Kinase Substrates in Arabidopsis thaliana Through Use of Tandem Metal Oxide Affinity Chromatography*

    PubMed Central

    Hoehenwarter, Wolfgang; Thomas, Martin; Nukarinen, Ella; Egelhofer, Volker; Röhrig, Horst; Weckwerth, Wolfram; Conrath, Uwe; Beckers, Gerold J. M.

    2013-01-01

    Mitogen-activated protein kinase (MPK) cascades are important for eukaryotic signal transduction. They convert extracellular stimuli (e.g. some hormones, growth factors, cytokines, microbe- or damage-associated molecular patterns) into intracellular responses while at the same time amplifying the transmitting signal. By doing so, they ensure proper performance, and eventually survival, of a given organism, for example in times of stress. MPK cascades function via reversible phosphorylation of cascade components MEKKs, MEKs, and MPKs. In plants the identity of most MPK substrates remained elusive until now. Here, we provide a robust and powerful approach to identify and quantify, with high selectivity, site-specific phosphorylation of MPK substrate candidates in the model plant Arabidopsis thaliana. Our approach represents a two-step chromatography combining phosphoprotein enrichment using Al(OH)3-based metal oxide affinity chromatography, tryptic digest of enriched phosphoproteins, and TiO2-based metal oxide affinity chromatography to enrich phosphopeptides from complex protein samples. When applied to transgenic conditional gain-of-function Arabidopsis plants supporting in planta activation of MPKs, the approach allows direct measurement and quantification ex vivo of site-specific phosphorylation of several reported and many yet unknown putative MPK substrates in just a single experiment. PMID:23172892

  20. Process for the deposition of high temperature stress and oxidation resistant coatings on silicon-based substrates

    DOEpatents

    Sarin, Vinod K.

    1991-01-01

    A process for depositing a high temperature stress and oxidation resistant coating on a silicon nitride- or silicon carbide-based substrate body. A gas mixture is passed over the substrate at about 900.degree.-1500.degree. C. and about 1 torr to about ambient pressure. The gas mixture includes one or more halide vapors with other suitable reactant gases. The partial pressure ratios, flow rates, and process times are sufficient to deposit a continuous, fully dense, adherent coating. The halide and other reactant gases are gradually varied during deposition so that the coating is a graded coating of at least two layers. Each layer is a graded layer changing in composition from the material over which it is deposited to the material of the layer and further to the material, if any, deposited thereon, so that no clearly defined compositional interfaces exist. The gases and their partial pressures are varied according to a predetermined time schedule and the halide and other reactant gases are selected so that the layers include (a) an adherent, continuous intermediate layer about 0.5-20 microns thick of an aluminum nitride or an aluminum oxynitride material, over and chemically bonded to the substrate body, and (b) an adherent, continuous first outer layer about 0.5-900 microns thick including an oxide of aluminum or zirconium over and chemically bonded to the intermediate layer.

  1. Process for the deposition of high temperature stress and oxidation resistant coatings on silicon-based substrates

    DOEpatents

    Sarin, V.K.

    1991-07-30

    A process is disclosed for depositing a high temperature stress and oxidation resistant coating on a silicon nitride- or silicon carbide-based substrate body. A gas mixture is passed over the substrate at about 900--1500 C and about 1 torr to about ambient pressure. The gas mixture includes one or more halide vapors with other suitable reactant gases. The partial pressure ratios, flow rates, and process times are sufficient to deposit a continuous, fully dense, adherent coating. The halide and other reactant gases are gradually varied during deposition so that the coating is a graded coating of at least two layers. Each layer is a graded layer changing in composition from the material over which it is deposited to the material of the layer and further to the material, if any, deposited thereon, so that no clearly defined compositional interfaces exist. The gases and their partial pressures are varied according to a predetermined time schedule and the halide and other reactant gases are selected so that the layers include (a) an adherent, continuous intermediate layer about 0.5-20 microns thick of an aluminum nitride or an aluminum oxynitride material, over and chemically bonded to the substrate body, and (b) an adherent, continuous first outer layer about 0.5-900 microns thick including an oxide of aluminum or zirconium over and chemically bonded to the intermediate layer.

  2. Investigation for surface resistance of yttrium-barium-copper-oxide thin films on various substrates for microwave applications

    NASA Astrophysics Data System (ADS)

    Yao, Hongjun

    High temperature superconducting (HTS) materials such as YBCO (Yttrium-Barium-Copper-Oxide) are very attractive in microwave applications because of their extremely low surface resistance. In the proposed all-HTS tunable filter, a layer of HTS thin film on a very thin substrate (100 mum) is needed to act as the toractor that can be rotated to tune the frequency. In order to provide more substrate candidates that meet both electrical and mechanical requirements for this special application, surface resistance of YBCO thin films on various substrates was measured using microstrip ring resonator method. For alumina polycrystalline substrate, a layer of YSZ (Yttrium stabilized Zirconia) was deposited using IBAD (ion beam assisted deposition) method prior to YBCO deposition. The surface resistance of the YBCO thin film on alumina was found to be 22 mO due to high-angle grain boundary problem caused by the mixed in-plane orientations and large FWHM (full width at half maximum) of the thin film. For YBCO thin films on a YSZ single crystal substrate, the surface resistance showed even higher value of 30 mO because of the mixed in-plane orientation problem. However, by annealing the substrate in 200 Torr oxygen at 730°C prior to deposition, the in-plane orientation of YBCO thin films can be greatly improved. Therefore, the surface resistance decreased to 1.4 mO, which is still more than an order higher than the reported best value. The YBCO thin films grown on LaAlO3 single crystal substrate showed perfect in-plane orientation with FWHM less 1°. The surface resistance was as low as 0.032 mO. A tunable spiral resonator made of YBCO thin film on LaAlO3 single crystal substrate demonstrated that the resonant frequency can be tuned in a rang as large as 500 MHz by changing the gap between toractor and substrate. The Q-factor was more than 12,000, which ensured the extraordinarily high sensitivity for the proposed all-HTS tunable filter.

  3. An overview of appetite decline in older people.

    PubMed

    Pilgrim, Anna L; Robinson, Sian M; Sayer, Avan Aihie; Roberts, Helen C

    2015-06-01

    Poor appetite is a common problem in older people living at home and in care homes, as well as hospital inpatients. It can contribute to weight loss and nutritional deficiencies, and associated poor healthcare outcomes, including increased mortality. Understanding the causes of reduced appetite and knowing how to measure it will enable nurses and other clinical staff working in a range of community and hospital settings to identify patients with impaired appetite. A range of strategies can be used to promote better appetite and increase food intake. PMID:26018489

  4. Consistency of metabolic responses and appetite sensations under postabsorptive and postprandial conditions.

    PubMed

    Gonzalez, Javier T; Veasey, Rachel C; Rumbold, Penny L S; Stevenson, Emma J

    2012-10-01

    The present study aimed to investigate the reliability of metabolic and subjective appetite responses under fasted conditions and following consumption of a cereal-based breakfast. Twelve healthy, physically active males completed two postabsorption (PA) and two postprandial (PP) trials in a randomised order. In PP trials a cereal based breakfast providing 1859 kJ of energy was consumed. Expired gas samples were used to estimate energy expenditure and fat oxidation and 100mm visual analogue scales were used to determine appetite sensations at baseline and every 30 min for 120 min. Reliability was assessed using limits of agreement, coefficient of variation (CV), intraclass coefficient of correlation and 95% confidence limits of typical error. The limits of agreement and typical error were 292.0 and 105.5 kJ for total energy expenditure, 9.3 and 3.4 g for total fat oxidation and 22.9 and 8.3mm for time-averaged AUC for hunger sensations, respectively over the 120 min period in the PP trial. The reliability of energy expenditure and appetite in the 2h response to a cereal-based breakfast would suggest that an intervention requires a 211 kJ and 16.6mm difference in total postprandial energy expenditure and time-averaged hunger AUC to be meaningful, fat oxidation would require a 6.7 g difference which may not be sensitive to most meal manipulations. PMID:22369956

  5. Laser-induced dehydration of graphite oxide coatings on polymer substrates

    SciTech Connect

    Longo, Angela Palomba, Mariano; Carotenuto, Gianfranco; Nicolais, Luigi; Orabona, Emanuele; Maddalena, Pasqualino; Ambrosio, Antonio

    2014-05-15

    Nanosized graphite has been oxidized by the Hummers method to give high quality graphite oxide. This reaction is characterized by a very fast kinetic behavior and a high yield. The produced graphite oxide has been conveniently used to pattern graphene by using a standard photolithographic method, and the resulting systems have been characterized by optical microscopy (OM), scanning electron microscopy (SEM) and by Fourier transform infrared spectroscopy (FT-IR) and Visible-Near Infrared spectroscopy (Vis-NIR)

  6. Facile fabrication of Ag dendrite-integrated anodic aluminum oxide membrane as effective three-dimensional SERS substrate

    NASA Astrophysics Data System (ADS)

    Zhang, Cong-yun; Lu, Ya; Zhao, Bin; Hao, Yao-wu; Liu, Ya-qing

    2016-07-01

    A novel surface enhanced Raman scattering (SERS)-active substrate has been successfully developed, where Ag-dendrites are assembled on the surface and embedded in the channels of anodic aluminum oxide (AAO) membrane, via electrodeposition in AgNO3/PVP aqueous system. Reaction conditions were systematically investigated to attain the best Raman enhancement. The growth mechanism of Ag dendritic nanostructures has been proposed. The Ag dendrite-integrated AAO membrane with unique hierarchical structures exhibits high SERS activity for detecting rhodamine 6G with a detection limit as low as 1 × 10-11 M. Furthermore, the three-dimensional (3D) substrates display a good reproducibility with the average intensity variations at the major Raman peak less than 12%. Most importantly, the 3D SERS substrates without any surface modification show an outstanding SERS response for the molecules with weak affinity for noble metal surfaces. The potential application for the detection of polycyclic aromatic hydrocarbons (PAHs) was evaluated with fluoranthene as Raman target molecule and a sensitive SERS detection with a limit down to 10-8 M was reached. The 3D SERS-active substrate shows promising potential for rapid detection of trace organic pollutants even weak affinity molecules in the environment.

  7. Optimization of substrate-target distance for pulsed laser deposition of tungsten oxide thin films using Langmuir probe

    NASA Astrophysics Data System (ADS)

    Panda, A. Kumar; Singh, A.; Thirumurugesan, R.; Kuppusami, P.; Mohandas, E.

    2015-09-01

    The paper investigates the spatial and temporal variation of laser produced plasma of tungsten oxide using a Langmuir probe. The plasma was produced by laser ablation of tungsten oxide target using an Excimer laser of wavelength 248 nm. Our experimental studies confirmed that oxygen partial pressure (P) of 2× 10-2 mbar is sufficient enough to get stoichiometric tungsten oxide thin films and the plume dynamics was diagnosed for their spatial and temporal behaviour at the above optimised oxygen pressure. Spatial distribution was recorded with the target to substrate distance (D) ranging from the target position to a distance of 75 mm away from the target, whereas the temporal variation was taken in the range of 0-50 μ S with an interval of 0.5 μ S. The average electron densities were found to be maximum at 30 mm from the target position. However, ion density was constant beyond the probe distance of 45 mm from the target. The plasma current was found to be maximum at 28 μ S. The target to substrate distance was optimized for homogenous adherent good quality thin films using plasma parameters such as ion density and average electron density obtained at different oxygen pressure. The target distance and background gas pressure were correlated as PD scaling law and fitted as PD3 in the model.

  8. Role of surfactant-mediated electrodeposited titanium oxide substrate in improving electrocatalytic features of supported platinum particles

    NASA Astrophysics Data System (ADS)

    Spătaru, Tanţa; Preda, Loredana; Osiceanu, Petre; Munteanu, Cornel; Anastasescu, Mihai; Marcu, Maria; Spătaru, Nicolae

    2014-01-01

    A new hybrid system with improved photocatalytic and electrocatalytic performances was obtained by two-step potentiostatic deposition on highly boron-doped diamond (BDD) substrate. First, hydrated TiO2 was anodically deposited from a TiCl3 aqueous solution, both in the presence and in the absence of sodium dodecyl sulfate (SDS). The study of the UV irradiation effect evidenced that titanium oxide coatings obtained by surfactant-assisted electrodeposition (TiO2:SDS) exhibit enhanced photocurrent, due to its very rough texture and presumably to better efficiency of charge carrier separation. Electrochemical deposition of platinum on the oxide-coated BDD was carried out in a second step and AFM, SEM and XPS measurements have shown that, on the TiO2:SDS substrate, Pt particles are smaller, more uniformly distributed, and tend to form clusters, leading to a specific surface area of the electrocatalyst of ca. 6.55 m2 g-1. Carbon monoxide stripping experiments demonstrated that, when deposited on TiO2:SDS, Pt particles are also less sensitive to CO-poisoning during methanol anodic oxidation.

  9. Oxide mediated liquid-solid growth of high aspect ratio aligned gold silicide nanowires on Si(110) substrates.

    PubMed

    Bhatta, Umananda M; Rath, Ashutosh; Dash, Jatis K; Ghatak, Jay; Yi-Feng, Lai; Liu, Chuan-Pu; Satyam, P V

    2009-11-18

    Silicon nanowires grown using the vapor-liquid-solid method are promising candidates for nanoelectronics applications. The nanowires grow from an Au-Si catalyst during silicon chemical vapor deposition. In this paper, the effect of temperature, oxide at the interface and substrate orientation on the nucleation and growth kinetics during formation of nanogold silicide structures is explained using an oxide mediated liquid-solid growth mechanism. Using real time in situ high temperature transmission electron microscopy (with 40 ms time resolution), we show the formation of high aspect ratio ( approximately 15.0) aligned gold silicide nanorods in the presence of native oxide at the interface during in situ annealing of gold thin films on Si(110) substrates. Steps observed in the growth rate and real time electron diffraction show the existence of liquid Au-Si nano-alloy structures on the surface besides the un-reacted gold nanostructures. These results might enable us to engineer the growth of nanowires and similar structures with an Au-Si alloy as a catalyst. PMID:19843987

  10. Oxide mediated liquid-solid growth of high aspect ratio aligned gold silicide nanowires on Si(110) substrates

    NASA Astrophysics Data System (ADS)

    Bhatta, Umananda M.; Rath, Ashutosh; Dash, Jatis K.; Ghatak, Jay; Yi-Feng, Lai; Liu, Chuan-Pu; Satyam, P. V.

    2009-11-01

    Silicon nanowires grown using the vapor-liquid-solid method are promising candidates for nanoelectronics applications. The nanowires grow from an Au-Si catalyst during silicon chemical vapor deposition. In this paper, the effect of temperature, oxide at the interface and substrate orientation on the nucleation and growth kinetics during formation of nanogold silicide structures is explained using an oxide mediated liquid-solid growth mechanism. Using real time in situ high temperature transmission electron microscopy (with 40 ms time resolution), we show the formation of high aspect ratio (≈15.0) aligned gold silicide nanorods in the presence of native oxide at the interface during in situ annealing of gold thin films on Si(110) substrates. Steps observed in the growth rate and real time electron diffraction show the existence of liquid Au-Si nano-alloy structures on the surface besides the un-reacted gold nanostructures. These results might enable us to engineer the growth of nanowires and similar structures with an Au-Si alloy as a catalyst.

  11. Influence of superalloy substrate roughness on adhesion and oxidation behavior of magnetron-sputtered NiCoCrAlY coatings

    NASA Astrophysics Data System (ADS)

    Li, Zhiming; Qian, Shiqiang; Wang, Wei

    2011-10-01

    The present study has been conducted in order to determine the influence of superalloy substrate roughness on adhesion and oxidation behavior of magnetron-sputtered NiCoCrAlY coatings. Six types of coating samples with different substrate roughness were tested. The surface roughness and real surface area of both the substrates and coatings were studied by atomic force microscopy (AFM) techniques. The scratch tests performed at progressive loads were employed to evaluate the adhesion of the coatings. Cyclic oxidation tests were performed at 1100 °C in air for 50 cycles, each cycle consisting of 1 h heating in the tube furnace followed by 15 min cooling in the open air. The AFM measurements exhibit that the surface roughness of the sputtered NiCoCrAlY coating increases with the increasing of the superalloy substrate roughness. The NiCoCrAlY coatings present slightly lower roughness than the corresponding superalloy substrate. The scratch adhesion tests indicate that the coatings on substrates with a smoother surface possess better adhesion than on those with a rougher surface. Both the real surface area and oxidation weight gain of the coatings decrease with the decreasing of the superalloy substrate roughness. The NiCoCrAlY coating sputtered on the superalloy substrate with lower roughness provides relatively higher antioxidant protection than that provided by the coating with rougher substrate.

  12. Effects of MAR-M247 substrate (modified) composition on coating oxidation coating/substrate interdiffusion. M.S. Thesis. Final Report; [protective coatings for hot section components of gas turbine engines

    NASA Technical Reports Server (NTRS)

    Pilsner, B. H.

    1985-01-01

    The effects of gamma+gamma' Mar-M247 substrate composition on gamma+beta Ni-Cr-Al-Zr coating oxidation and coating/substrate interdiffusion were evaluated. These results were also compared to a prior study for a Ni-Cr-Al-Zr coated gamma Ni-Cr-Al substrate with equivalent Al and Cr atomic percentages. Cyclic oxidation behavior at 1130 C was investigated using change in weight curves. Concentration/distance profiles were measured for Al, Cr, Co, W, and Ta. The surface oxides were examined by X-ray diffraction and scanning electron microscopy. The results indicate that variations of Ta and C concentrations in the substrate do not affect oxidation resistance, while additions of grain boundary strengthening elements (Zr, Hf, B) increase oxidation resistance. In addition, the results indicate that oxidation phenomena in gamma+beta/gamma+gamma' Mar-M247 systems have similar characteristics to the l gamma+beta/gamma Ni-Cr-Al system.

  13. Fabrication of p-type porous silicon nanowire with oxidized silicon substrate through one-step MACE

    SciTech Connect

    Li, Shaoyuan; Ma, Wenhui; Zhou, Yang; Chen, Xiuhua; Xiao, Yongyin; Ma, Mingyu; Wei, Feng; Yang, Xi

    2014-05-01

    In this paper, the simple pre-oxidization process is firstly used to treat the starting silicon wafer, and then MPSiNWs are successfully fabricated from the moderately doped wafer by one-step MACE technology in HF/AgNO{sub 3} system. The PL spectrum of MPSiNWs obtained from the oxidized silicon wafers show a large blue-shift, which can be attributed to the deep Q. C. effect induced by numerous mesoporous structures. The effects of HF and AgNO{sub 3} concentration on formation of SiNWs were carefully investigated. The results indicate that the higher HF concentration is favorable to the growth of SiNWs, and the density of SiNWs is significantly reduced when Ag{sup +} ions concentrations are too high. The deposition behaviors of Ag{sup +} ions on oxidized and unoxidized silicon surface were studied. According to the experimental results, a model was proposed to explain the formation mechanism of porous SiNWs by etching the oxidized starting silicon. - Graphical abstract: Schematic cross-sectional views of PSiNWs array formation by etching oxidized silicon wafer in HF/AgNO{sub 3} solution. (A) At the starting point; (B) during the etching process; and (C) after Ag dendrites remove. - Highlights: • Prior to etching, a simple pre-oxidation is firstly used to treat silicon substrate. • The medially doped p-type MPSiNWs are prepared by one-step MACE. • Deposition behaviors of Ag{sup +} ions on oxidized and unoxidized silicon are studied. • A model is finally proposed to explain the formation mechanism of PSiNWs.

  14. Electrochemical investigation of chromium oxide-coated Ti-6Al-4V and Co-Cr-Mo alloy substrates.

    PubMed

    Swaminathan, Viswanathan; Zeng, Haitong; Lawrynowicz, Daniel; Zhang, Zongtao; Gilbert, Jeremy L

    2011-08-01

    Hard coatings for articulating surfaces of total joint replacements may improve the overall wear resistance. However, any coating approach must take account of changes in corrosion behavior. This preliminary assessment analyzes the corrosion kinetics, impedance and mechanical-electrochemical stability of 100 μm thick plasma sprayed chromium oxide (Cr₂O₃) coatings on bearing surfaces in comparison to the native alloy oxide films on Co-Cr-Mo and Ti-6Al-6V. Cyclic potentiodynamic polarization, electrochemical impedance spectroscopy, and mechanical abrasion under potentiostatic conditions were performed on coated and substrate surfaces in physiological saline. SEM analysis characterized the coating morphology. The results showed that the corrosion current density values of chromium oxide coatings (0.4-1.2 μA/cm²) were of the same order of magnitude as Ti-6Al-4V alloy. Mechanical abrasion did not increase corrosion rates of chromium oxide coatings but did for uncoated Co-Cr-Mo and Ti-6Al-4V. The impedance response of chromium oxide coatings was very different than Co-Cr-Mo and Ti-6Al-4V native oxides characterized by a defected coating model. More of a frequency-independent purely resistive response was seen in mid-frequency range for the coatings (CPE(coat) : 40-280 nF/cm² (rad/s)(1-α) , α: 0.67-0.83) whereas a more capacitive character is seen for Co-Cr-Mo and Ti-6Al-4V (CPE(ox) around 20 μF/cm² (rad/s)(1-α) , α around 0.9). Pores, interparticle gaps and incomplete fusion typical for thermal spray coatings were present in these oxides which could have influenced corrosion resistance. The coating microstructure could have allowed some fluid penetration. Overall, these coatings appear to have suitable corrosion properties for wear surfaces. PMID:21648063

  15. Zinc oxide films chemically grown onto rigid and flexible substrates for TFT applications

    NASA Astrophysics Data System (ADS)

    Suchea, M.; Kornilios, N.; Koudoumas, E.

    2010-10-01

    This contribution presents some preliminary results regarding the use of a chemical route for the growth of good quality ZnO thin films that can be used for the fabrication of thin film transistors (TFTs). The films were grown at rather low temperature (60 °C) on glass and PET substrates using non-aqueous (zinc acetate dihydrate in methanol) precursor solution and their surface morphology, crystalline structure, optical transmittance and electrical characteristics were studied. The study indicated that good quality films with desirable ZnO structure onto rigid and flexible substrates can be obtained, using a simple, cheap, low temperature chemical growth method.

  16. Samarium electrodeposited acetate and oxide thin films on stainless steel substrate characterized by XPS

    DOE PAGESBeta

    Myhre, Kristian; Burns, Jonathan; Meyer, Harry; Sims, Nathan; Boll, Rose

    2016-06-01

    Characterization of a samarium thin film deposited on a stainless steel substrate using molecular electrodeposition was carried out using a Thermo Scientific K-Alpha X-ray photoelectron spectrometer. We studied two types of samarium electrodeposition samples, one as-deposited and one heated to 700 °C in an air flow. Survey scans include peaks coming from the stainless steel substrate, such as Fe and Cr. An X-ray photoelectron spectroscopy (XPS) survey spectrum, Sm 3d, C 1s, and O 1s narrow scans are shown. It was determined that the heating process decomposed the deposited Sm acetate to Sm2O3 using XPS.

  17. Ultrasensitive Strain Sensor Produced by Direct Patterning of Liquid Crystals of Graphene Oxide on a Flexible Substrate.

    PubMed

    Coskun, M Bulut; Akbari, Abozar; Lai, Daniel T H; Neild, Adrian; Majumder, Mainak; Alan, Tuncay

    2016-08-31

    Ultrasensitive flexible strain sensors were developed through the combination of shear alignment of a high concentration graphene oxide (GO) dispersion with fast and precise patterning of multiple rectangular features on a flexible substrate. Resistive changes in the reduced GO films were investigated under various uniaxial strain cycles ranging from 0.025 to 2%, controlled with a motorized nanopositioning stage. The devices uniquely combine a very small detection limit (0.025%) and a high gauge factor with a rapid fabrication process conducive to batch production. PMID:27490520

  18. Crossed ferric oxide nanosheets supported cobalt oxide on 3-dimensional macroporous Ni foam substrate used for diesel soot elimination under self-capture contact mode

    NASA Astrophysics Data System (ADS)

    Cao, Chunmei; Li, Xingang; Zha, Yuqing; Zhang, Jing; Hu, Tiandou; Meng, Ming

    2016-03-01

    Crossed Fe2O3 nanosheets supported cobalt oxide nanoparticles on three-dimensionally macroporous nickel foam substrate (xCo/Fe-NF) was designed and successfully prepared through a facile hydrothermal and impregnation route. These catalysts showed high catalytic soot combustion activities under self-capture contact mode. The three-dimensional macroporous structures of Ni foam and the crossed Fe2O3 nanosheets constituted macroporous voids can greatly increase the contact efficiency between soot particulates and catalysts. The interaction between Co and Fe facilitated the activation of the Fe-O bond and increased the amounts of active oxygen species, thus improving the redox property of the catalysts. The 0.6Co/Fe-NF catalyst exhibited the highest turnover frequency (TOF) for soot combustion, which is in good accordance with the largest amount of active oxygen species. Based upon the catalytic performance and multiple characterization results, two reaction pathways for soot oxidation are identified, namely, the direct oxidation by the activated oxygen species via oxygen vacancies and the NOx-aided soot oxidation.Crossed Fe2O3 nanosheets supported cobalt oxide nanoparticles on three-dimensionally macroporous nickel foam substrate (xCo/Fe-NF) was designed and successfully prepared through a facile hydrothermal and impregnation route. These catalysts showed high catalytic soot combustion activities under self-capture contact mode. The three-dimensional macroporous structures of Ni foam and the crossed Fe2O3 nanosheets constituted macroporous voids can greatly increase the contact efficiency between soot particulates and catalysts. The interaction between Co and Fe facilitated the activation of the Fe-O bond and increased the amounts of active oxygen species, thus improving the redox property of the catalysts. The 0.6Co/Fe-NF catalyst exhibited the highest turnover frequency (TOF) for soot combustion, which is in good accordance with the largest amount of active oxygen

  19. Versatile Oxidation Methods for Organic and Inorganic Substrates Catalyzed by Platinum-Group Metals on Carbons.

    PubMed

    Sawama, Yoshinari; Asai, Shota; Monguchi, Yasunari; Sajiki, Hironao

    2016-02-01

    Platinum-group metals on activated carbon catalysts, represented by Pd/C, Ru/C, Rh/C, etc., are widely utilized to accomplish green and sustainable organic reactions due to their favorable features, such as easy handling, recoverability, and reusability. The efficient oxidation methods of various organic compounds using heterogeneous platinum-group metals on carbons with or without added oxidants are summarized in this Personal Account. The oxidation of internal alkynes into diketones was effectively catalyzed by Pd/C in the presence of dimethyl sulfoxide and molecular oxygen or pyridine N-oxide. The Pd/C-catalyzed mild combustion of gaseous hydrogen with molecular oxygen provided hydrogen peroxide, which could be directly utilized for the oxidation of sulfide derivatives into sulfoxides. Furthermore, the Ru/C-catalyzed aerobic oxidation of primary and secondary alcohols gave the corresponding aldehydes and ketones, respectively. On the other hand, the dehydrogenative oxidation of secondary alcohols into ketones was achieved using Rh/C in water, and primary alcohols were effectively dehydrogenated by Pd/C in water under mildly reduced pressure to produce carboxylic acids. PMID:26666634

  20. The extended amygdala and salt appetite

    NASA Technical Reports Server (NTRS)

    Johnson, A. K.; de Olmos, J.; Pastuskovas, C. V.; Zardetto-Smith, A. M.; Vivas, L.

    1999-01-01

    Both chemo- and mechanosensitive receptors are involved in detecting changes in the signals that reflect the status of body fluids and of blood pressure. These receptors are located in the systemic circulatory system and in the sensory circumventricular organs of the brain. Under conditions of body fluid deficit or of marked changes in fluid distribution, multiple inputs derived from these humoral and neural receptors converge on key areas of the brain where the information is integrated. The result of this central processing is the mobilization of homeostatic behaviors (thirst and salt appetite), hormone release, autonomic changes, and cardiovascular adjustments. This review discusses the current understanding of the nature and role of the central and systemic receptors involved in the facilitation and inhibition of thirst and salt appetite and on particular components of the central neural network that receive and process input derived from fluid- and cardiovascular-related sensory systems. Special attention is paid to the structures of the lamina terminalis, the area postrema, the lateral parabrachial nucleus, and their association with the central nucleus of the amygdala and the bed nucleus of the stria terminalis in controlling the behaviors that participate in maintaining body fluid and cardiovascular homeostasis.

  1. Self-aligned graphene field-effect transistors on SiC (0001) substrates with self-oxidized gate dielectric

    NASA Astrophysics Data System (ADS)

    Jia, Li; Cui, Yu; Li, Wang; Qingbin, Liu; Zezhao, He; Shujun, Cai; Zhihong, Feng

    2014-07-01

    A scalable self-aligned approach is employed to fabricate monolayer graphene field-effect transistors on semi-insulated 4H-SiC (0001) substrates. The self-aligned process minimized access resistance and parasitic capacitance. Self-oxidized Al2O3, formed by deposition of 2 nm Al followed by exposure in air to be oxidized, is used as gate dielectric and shows excellent insulation. An intrinsic cutoff frequency of 34 GHz and maximum oscillation frequency of 36.4 GHz are realized for the monolayer graphene field-effect transistor with a gate length of 0.2 μm. These studies show a pathway to fabricate graphene transistors for future applications in ultra-high frequency circuits.

  2. High critical current density YBa 2Cu 3O 7- δ films on surface-oxidized metallic substrates

    NASA Astrophysics Data System (ADS)

    Matsumoto, Kaname; Kim, SeokBeom; Yamagiwa, Katsuya; Koike, Yoshihiro; Hirabayashi, Izumi; Watanabe, Tomonori; Uno, Naoki; Ikeda, Masaru

    2000-06-01

    YBa 2Cu 3O 7-δ (YBCO) films with high critical current density ( Jc) were fabricated on nickel tapes buffered with bi-axially textured NiO prepared by surface-oxidation epitaxy (SOE). The effects of oxide cap layers, such as YSZ, CeO 2 and MgO, on the SOE-grown NiO were investigated to improve the superconducting properties of the YBCO films on NiO. By inserting a thin MgO cap layer between NiO layer and YBCO film, a Jc of 3×10 5 A/cm 2 (77 K, 0 T) was achieved. This result indicates the potentiality of the SOE method. In this paper, the application of the NiO/Ni substrate to non-vacuum processings, such as metal-organic deposition (MOD) and liquid phase epitaxy (LPE) will be also introduced.

  3. Atomic layer deposition of ultrathin blocking layer for low-temperature solid oxide fuel cell on nanoporous substrate

    SciTech Connect

    Yu, Wonjong; Cho, Gu Young; Noh, Seungtak; Tanveer, Waqas Hassan; Cha, Suk Won; Ji, Sanghoon; An, Jihwan

    2015-01-15

    An ultrathin yttria-stabilized zirconia (YSZ) blocking layer deposited by atomic layer deposition (ALD) was utilized for improving the performance and reliability of low-temperature solid oxide fuel cells (SOFCs) supported by an anodic aluminum oxide substrate. Physical vapor-deposited YSZ and gadolinia-doped ceria (GDC) electrolyte layers were deposited by a sputtering method. The ultrathin ALD YSZ blocking layer was inserted between the YSZ and GDC sputtered layers. To investigate the effects of an inserted ultrathin ALD blocking layer, SOFCs with and without an ultrathin ALD blocking layer were electrochemically characterized. The open circuit voltage (1.14 V) of the ALD blocking-layered SOFC was visibly higher than that (1.05 V) of the other cell. Furthermore, the ALD blocking layer augmented the power density and improved the reproducibility.

  4. Sn and Cu oxide nanoparticles deposited on TiO2 nanoflower 3D substrates by Inert Gas Condensation technique

    NASA Astrophysics Data System (ADS)

    Kusior, A.; Kollbek, K.; Kowalski, K.; Borysiewicz, M.; Wojciechowski, T.; Adamczyk, A.; Trenczek-Zajac, A.; Radecka, M.; Zakrzewska, K.

    2016-09-01

    Sn and Cu oxide nanoparticles were deposited by Inert Gas Condensation (IGC) technique combined with dc magnetron sputtering onto nanoflower TiO2 3D substrates obtained in the oxidation process of Ti-foil in 30% H2O2. Sputtering parameters such as insertion length and Ar/He flow rates were optimized taking into account the nanostructure morphology. Comparative studies with hydrothermal method were carried out. Surface properties of the synthesized nanomaterials were studied by Scanning Electron Microscopy, SEM, Atomic Force Microscopy, AFM, and X-ray Photoelectron Spectroscopy, XPS. X-ray diffraction, XRD and Raman spectroscopy were performed in order to determine phase composition. Impedance spectroscopy demonstrated the influence of nanoparticles on the electrical conductivity.

  5. Differential Recruitment of Distinct Amygdalar Nuclei across Appetitive Associative Learning

    ERIC Educational Resources Information Center

    Cole, Sindy; Powell, Daniel J.; Petrovich, Gorica D.

    2013-01-01

    The amygdala is important for reward-associated learning, but how distinct cell groups within this heterogeneous structure are recruited during appetitive learning is unclear. Here we used Fos induction to map the functional amygdalar circuitry recruited during early and late training sessions of Pavlovian appetitive conditioning. We found that a…

  6. Appetitive Motivation and Negative Emotion Reactivity among Remitted Depressed Youth

    ERIC Educational Resources Information Center

    Hankin, Benjamin L.; Wetter, Emily K.; Flory, Kate

    2012-01-01

    Depression has been characterized as involving altered appetitive motivation and emotional reactivity. Yet no study has examined objective indices of emotional reactivity when the appetitive/approach system is suppressed in response to failure to attain a self-relevant goal and desired reward. Three groups of youth (N = 98, ages 9-15; remitted…

  7. Multifunctional porous titanium oxide coating with apatite forming ability and photocatalytic activity on a titanium substrate formed by plasma electrolytic oxidation.

    PubMed

    Akatsu, T; Yamada, Y; Hoshikawa, Y; Onoki, T; Shinoda, Y; Wakai, F

    2013-12-01

    Plasma electrolytic oxidation (PEO) was used to make a multifunctional porous titanium oxide (TiO2) coating on a titanium substrate. The key finding of this study is that a highly crystalline TiO2 coating can be made by performing the PEO in an ammonium acetate (CH3COONH4) solution; the PEO coating was formed by alternating between rapid heating by spark discharges and quenching in the solution. The high crystallinity of the TiO2 led to the surface having multiple functions, including apatite forming ability and photocatalytic activity. Hydroxyapatite formed on the PEO coating when it was soaked in simulated body fluid. The good apatite forming ability can be attributed to the high density of hydroxyl groups on the anatase and rutile phases in the coating. The degradation of methylene blue under ultraviolet radiation indicated that the coating had high photocatalytic activity. PMID:24094199

  8. Oxidation of Phe454 in the Gating Segment Inactivates Trametes multicolor Pyranose Oxidase during Substrate Turnover

    PubMed Central

    Volc, Jindrich; Peterbauer, Clemens K.; Leitner, Christian; Haltrich, Dietmar

    2016-01-01

    The flavin-dependent enzyme pyranose oxidase catalyses the oxidation of several pyranose sugars at position C-2. In a second reaction step, oxygen is reduced to hydrogen peroxide. POx is of interest for biocatalytic carbohydrate oxidations, yet it was found that the enzyme is rapidly inactivated under turnover conditions. We studied pyranose oxidase from Trametes multicolor (TmPOx) inactivated either during glucose oxidation or by exogenous hydrogen peroxide using mass spectrometry. MALDI-MS experiments of proteolytic fragments of inactivated TmPOx showed several peptides with a mass increase of 16 or 32 Da indicating oxidation of certain amino acids. Most of these fragments contain at least one methionine residue, which most likely is oxidised by hydrogen peroxide. One peptide fragment that did not contain any amino acid residue that is likely to be oxidised by hydrogen peroxide (DAFSYGAVQQSIDSR) was studied in detail by LC-ESI-MS/MS, which showed a +16 Da mass increase for Phe454. We propose that oxidation of Phe454, which is located at the flexible active-site loop of TmPOx, is the first and main step in the inactivation of TmPOx by hydrogen peroxide. Oxidation of methionine residues might then further contribute to the complete inactivation of the enzyme. PMID:26828796

  9. Catalyst-Free Synthesis of ZnO Nanowires on Oxidized Silicon Substrate for Gas Sensing Applications.

    PubMed

    Behera, B; Chandra, S

    2015-06-01

    In the present work, we report the synthesis of nanostructured ZnO by oxidation of zinc film without using a seed or catalyst layer. The zinc films were deposited on oxidized Si substrates by RF magnetron sputtering process. These were oxidized in dry and wet air/oxygen ambient. The optimized process yielded long nanowires of ZnO having diameter of around 60-70 nm and spread uniformly over the surface. The effect of oxidation temperature, time, Zn film thickness and the ambient has strong influence on the morphology of resulting nanostruxctured ZnO film. The films were characterized by scanning electron microscopy for morphological studies and X-ray diffraction (XRD) analysis to study the phase of the nanostructured ZnO. Room temperature photoluminescence (PL) measurements of the nanowires show UV and green emission. A sensor was designed and fabricated using nanostructured ZnO film, incorporating inter-digital-electrode (IDE) for the measurement of resistance of the sensing layer. The gas sensing properties were investigated from the measurement of change in resistance when exposed to vapours of different volatile organic compound (VOC) such as acetone, ethanol, methanol and 2-propanol. The results suggest that ZnO nanowires fabricated by this method have potential application in gas sensors. PMID:26369077

  10. COSIM: A Finite-Difference Computer Model to Predict Ternary Concentration Profiles Associated with Oxidation and Interdiffusion of Overlay-Coated Substrates

    NASA Technical Reports Server (NTRS)

    Nesbitt, James A.

    2000-01-01

    A finite-difference computer program (COSIM) has been written which models the one-dimensional, diffusional transport associated with high-temperature oxidation and interdiffusion of overlay-coated substrates. The program predicts concentration profiles for up to three elements in the coating and substrate after various oxidation exposures. Surface recession due to solute loss is also predicted. Ternary cross terms and concentration-dependent diffusion coefficients are taken into account. The program also incorporates a previously-developed oxide growth and spalling model to simulate either isothermal or cyclic oxidation exposures. In addition to predicting concentration profiles after various oxidation exposures, the program can also be used to predict coating fife based on a concentration dependent failure criterion (e.g., surface solute content drops to two percent). The computer code, written in an extension of FORTRAN 77, employs numerous subroutines to make the program flexible and easily modifiable to other coating oxidation problems.

  11. COSIM: A Finite-Difference Computer Model to Predict Ternary Concentration Profiles Associated With Oxidation and Interdiffusion of Overlay-Coated Substrates

    NASA Technical Reports Server (NTRS)

    Nesbitt, James A.

    2001-01-01

    A finite-difference computer program (COSIM) has been written which models the one-dimensional, diffusional transport associated with high-temperature oxidation and interdiffusion of overlay-coated substrates. The program predicts concentration profiles for up to three elements in the coating and substrate after various oxidation exposures. Surface recession due to solute loss is also predicted. Ternary cross terms and concentration-dependent diffusion coefficients are taken into account. The program also incorporates a previously-developed oxide growth and spalling model to simulate either isothermal or cyclic oxidation exposures. In addition to predicting concentration profiles after various oxidation exposures, the program can also be used to predict coating life based on a concentration dependent failure criterion (e.g., surface solute content drops to 2%). The computer code is written in FORTRAN and employs numerous subroutines to make the program flexible and easily modifiable to other coating oxidation problems.

  12. Estimation of the cytoplasmic pH of Coxiella burnetii and effect of substrate oxidation on proton motive force.

    PubMed Central

    Hackstadt, T

    1983-01-01

    The magnitude of the proton motive force generated during in vitro substrate oxidation by Coxiella burnetii was examined. The intracellular pH of C. burnetii varied from about 5.1 to 6.95 in resting cells over an extracellular pH range of 2 to 7. Similarly, delta psi varied from about 15 mV to -58 mV over approximately the same range of extracellular pH. Both components of the proton motive force increased during substrate oxidation, resulting in an increase in proton motive force from about -92 mV in resting cells to -153 mV in cells metabolizing glutamate at pH 4.2. The respiration-dependent increase in proton motive force was blocked by respiratory inhibitors, but the delta pH was not abolished even by the addition of proton ionophores such as carbonyl cyanide-m-chlorophenyl hydrazone or 2,4-dinitrophenol. Because of this apparently passive component of delta pH maintenance, the largest proton motive force was obtained at an extracellular pH too low to permit respiration. C. burnetii appears, therefore, to behave in many respects like other acidophilic bacteria. Such responses are proposed to contribute to the extreme resistance of C. burnetii to environmental conditions and subsequent activation upon entry into the phagolysosome of eucaryotic cells in which this organism multiplies. PMID:6302078

  13. Spontaneous Reduction and Assembly of Graphene oxide into Three-Dimensional Graphene Network on Arbitrary Conductive Substrates

    PubMed Central

    Hu, Chuangang; Zhai, Xiangquan; Liu, Lili; Zhao, Yang; Jiang, Lan; Qu, Liangti

    2013-01-01

    Chemical reduction of graphene oxide (GO) is the main route to produce the mass graphene-based materials with tailored surface chemistry and functions. However, the toxic reducing circumstances, multiple steps, and even incomplete removal of the oxygen-containing groups were involved, and the produced graphenes existed usually as the assembly-absent precipitates. Herein, a substrate-assisted reduction and assembly of GO (SARA-GO) method was developed for spontaneous formation of 3D graphene network on arbitrary conductive substrates including active and inert metals, semiconducting Si, nonmetallic carbon, and even indium-tin oxide glass without any additional reducing agents. The SARA-GO process offers a facile, efficient approach for constructing unique graphene assemblies such as microtubes, multi-channel networks, micropatterns, and allows the fabrication of high-performance binder-free rechargeable lithium-ion batteries. The versatile SARD-GO method significantly improves the processablity of graphenes, which could thus benefit many important applications in sensors and energy-related devices. PMID:23799368

  14. Crossed ferric oxide nanosheets supported cobalt oxide on 3-dimensional macroporous Ni foam substrate used for diesel soot elimination under self-capture contact mode.

    PubMed

    Cao, Chunmei; Li, Xingang; Zha, Yuqing; Zhang, Jing; Hu, Tiandou; Meng, Ming

    2016-03-21

    Crossed Fe2O3 nanosheets supported cobalt oxide nanoparticles on three-dimensionally macroporous nickel foam substrate (xCo/Fe-NF) was designed and successfully prepared through a facile hydrothermal and impregnation route. These catalysts showed high catalytic soot combustion activities under self-capture contact mode. The three-dimensional macroporous structures of Ni foam and the crossed Fe2O3 nanosheets constituted macroporous voids can greatly increase the contact efficiency between soot particulates and catalysts. The interaction between Co and Fe facilitated the activation of the Fe-O bond and increased the amounts of active oxygen species, thus improving the redox property of the catalysts. The 0.6Co/Fe-NF catalyst exhibited the highest turnover frequency (TOF) for soot combustion, which is in good accordance with the largest amount of active oxygen species. Based upon the catalytic performance and multiple characterization results, two reaction pathways for soot oxidation are identified, namely, the direct oxidation by the activated oxygen species via oxygen vacancies and the NOx-aided soot oxidation. PMID:26509240

  15. Osteogenic potential of in situ TiO2 nanowire surfaces formed by thermal oxidation of titanium alloy substrate

    NASA Astrophysics Data System (ADS)

    Tan, A. W.; Ismail, R.; Chua, K. H.; Ahmad, R.; Akbar, S. A.; Pingguan-Murphy, B.

    2014-11-01

    Titanium dioxide (TiO2) nanowire surface structures were fabricated in situ by a thermal oxidation process, and their ability to enhance the osteogenic potential of primary osteoblasts was investigated. Human osteoblasts were isolated from nasal bone and cultured on a TiO2 nanowires coated substrate to assess its in vitro cellular interaction. Bare featureless Ti-6Al-4V substrate was used as a control surface. Initial cell adhesion, cell proliferation, cell differentiation, cell mineralization, and osteogenic related gene expression were examined on the TiO2 nanowire surfaces as compared to the control surfaces after 2 weeks of culturing. Cell adhesion and cell proliferation were assayed by field emission scanning electron microscope (FESEM) and Alamar Blue reduction assay, respectively. The nanowire surfaces promoted better cell adhesion and spreading than the control surface, as well as leading to higher cell proliferation. Our results showed that osteoblasts grown onto the TiO2 nanowire surfaces displayed significantly higher production levels of alkaline phosphatase (ALP), extracellular (ECM) mineralization and genes expression of runt-related transcription factor (Runx2), bone sialoprotein (BSP), ostoepontin (OPN) and osteocalcin (OCN) compared to the control surfaces. This suggests the potential use of such surface modification on Ti-6Al-4V substrates as a promising means to improve the osteointegration of titanium based implants.

  16. Fabrication of SERS-active substrates using silver nanofilm-coated porous anodic aluminum oxide for detection of antibiotics.

    PubMed

    Chen, Jing; Feng, Shaolong; Gao, Fang; Grant, Edward; Xu, Jie; Wang, Shuo; Huang, Qian; Lu, Xiaonan

    2015-04-01

    We have developed a silver nanofilm-coated porous anodic aluminum oxide (AAO) as a surface-enhanced Raman scattering (SERS)-active substrate for the detection of trace level of chloramphenicol, a representative antibiotic in food systems. The ordered aluminum template generated during the synthesis of AAO serves as a patterned matrix on which a coated silver film replicates the patterned AAO matrix to form a 2-dimensional ordered nanostructure. We used atomic force microscopy and scanning electron microscopy images to determine the morphology of this nanosubstrate, and characterized its localized surface plasmon resonance by ultraviolet-visible reflection. We gauged the SERS effect of this nanosubstrate by confocal micro-Raman spectroscopy (782-nm laser), finding a satisfactory and consistent performance with enhancement factors of approximately 2 × 10(4) and a limit of detection for chloramphenicol of 7.5 ppb. We applied principal component analysis to determine the limit of quantification for chloramphenicol of 10 ppb. Using electromagnetic field theory, we developed a detailed mathematical model to explain the mechanism of Raman signal enhancement of this nanosubstrate. With simple sample pretreatment and separation steps, this silver nanofilm-coated AAO substrate could detect 50 ppb chloramphenicol in milk, indicating good potential as a reliable SERS-active substrate for rapid detection of chemical contaminants in agricultural and food products. PMID:25736080

  17. Influence of defects and processing parameters on the properties of indium tin oxide films on polyethylene napthalate substrate

    SciTech Connect

    Han, H.; Zoo, Yeongseok; Bhagat, S. K.; Lewis, J. S.; Alford, T. L.

    2007-09-15

    Indium tin oxide (ITO) thin films were deposited on polyethylene napthalate (PEN) by rf sputtering using different rf powers (60 and 120 W) and at different substrate temperatures (room temperature and 100 deg. C). Selected PEN substrates were pretreated using an Ar plasma before ITO sputter deposition. Rutherford backscattering spectrometry was used to determine the oxygen content in the films. Hall effect measurements were used to evaluate the electrical properties. In this paper the influence of defect structure, sputtering conditions, and the effect of annealing on the electrical and optical properties of ITO on PEN have been investigated. Electrical properties such as carrier concentration, mobility, and resistivity of the ITO films varied with rf power and substrate temperature. The electrical and optical properties of the films changed after annealing in air. This study also describes how the as-deposited amorphous ITO changes from amorphous to crystalline as a result of heat treatment, and investigates the effects of Sn defect clustering on electrical and optical properties of the ITO films.

  18. Ultrafast dynamics of ligand and substrate interaction in endothelial nitric oxide synthase under Soret excitation.

    PubMed

    Hung, Chih-Chang; Yabushita, Atsushi; Kobayashi, Takayoshi; Chen, Pei-Feng; Liang, Keng S

    2016-01-01

    Ultrafast transient absorption spectroscopy of endothelial NOS oxygenase domain (eNOS-oxy) was performed to study dynamics of ligand or substrate interaction under Soret band excitation. Photo-excitation dissociates imidazole ligand in <300fs, then followed by vibrational cooling and recombination within 2ps. Such impulsive bond breaking and late rebinding generate proteinquakes, which relaxes in several tens of picoseconds. The photo excited dynamics of eNOS-oxy with L-arginine substrate mainly occurs at the local site of heme, including ultrafast internal conversion within 400fs, vibrational cooling, charge transfer, and complete ground-state recovery within 1.4ps. The eNOS-oxy without additive is partially bound with water molecule, thus its photoexcited dynamics also shows ligand dissociation in <800fs. Then it followed by vibrational cooling coupled with charge transfer in 4.8ps, and recombination of ligand to distal side of heme in 12ps. PMID:27183248

  19. C-Myc regulates substrate oxidation patterns during early pressure-overload hypertrophy

    SciTech Connect

    Ledee, Dolena R.; Smith, Lincoln; Kajimoto, Masaki; Bruce, Margaret; Isern, Nancy G.; Xu, Chun; Portman, Michael A.; Olson, Aaron

    2013-11-26

    Pressure overload cardiac hypertrophy alters substrate metabolism. Prior work showed that myocardial inactivation of c-Myc (Myc) attenuated hypertrophy and decreased expression of glycolytic genes after aortic constriction. Accordingly, we hypothesize that Myc regulates substrate preferences for the citric acid cycle during pressure overload hypertrophy from transverse aortic constriction (TAC) and that these metabolic changes impact cardiac function and growth. To test this hypothesis, we subjected FVB mice with cardiac specific, inducible Myc inactivation (MycKO-TAC) and non-transgenic littermates (Cont-TAC) to transverse aortic constriction (n=7/group). A separate group underwent sham surgery (Sham, n=5). After two weeks, function was measured in isolated working hearts along with substrate fractional contributions to the citric acid cycle by using perfusate with 13C labeled mixed fatty acids, lactate, ketones and unlabeled glucose and insulin. Western blots were used to evaluate metabolic enzymes. Cardiac function was similar between groups after TAC although +dP/dT and -dP/dT trended towards improvement in MycKO-TAC versus Cont-TAC. Compared to Sham, Cont-TAC had increased free fatty acid fractional contribution with a concurrent decrease in unlabeled (presumably glucose) contribution. Myc inactivation (MycKO-TAC) inhibited these metabolic changes. Hypertrophy in general increased protein levels of PKM2; however this change was not linked to Myc status. Protein post-translation modification by O-GlcNAc was significantly greater in Cont-TAC versus both Sham and MycKO-TAC. In conclusion, Myc regulates substrate utilization during early pressure overload hypertrophy. Our results show that the metabolic switch during hypertrophy is not necessary to maintain cardiac function, but it may be important mechanism to promote cardiomyocyte growth. Myc also regulates protein O-GlcNAcylation during hypertrophy.

  20. Inclined-substrate deposition of biaxially textured magnesium oxide thin films for YBCO coated conductors.

    SciTech Connect

    Ma, B.; Li, M.; Jee, Y. A.; Koritala, R. E.; Fisher, B. L.; Balachandran, U.; Energy Technology

    2002-02-01

    Highly textured MgO films were grown by the inclined-substrate deposition (ISD) technique at a high deposition rate. A columnar grain with a roofing-tile-shaped surface was observed in these MgO films. X-ray pole figure, and {phi}- and {omega}-scan were used to characterize in-plane and out-of-plane textures. MgO films deposited when the incline angle {alpha} was 55 and 30 degrees exhibited the best in-plane and out-of-plane texture, respectively. High-quality YBCO films were epitaxially grown on ISD-MgO-buffered Hastelloy C substrates by pulsed laser deposition. {Tc}=88 K, with sharp transition, and j{sub c} values of {approx}2x10{sup 5} A/cm{sup 2} at 77 K in zero field were observed on films 5 mm wide and 1 cm long. This work has demonstrated that biaxially textured ISD MgO buffer layers deposited on metal substrates are excellent candidates for fabrication of high-quality YBCO coated conductors.

  1. Amygdala Dopamine Receptors Are Required for the Destabilization of a Reconsolidating Appetitive Memory1,2

    PubMed Central

    Merlo, Emiliano; Ratano, Patrizia; Ilioi, Elena C.; Robbins, Miranda A.L.S.; Everitt, Barry J.

    2015-01-01

    Abstract Disrupting maladaptive memories may provide a novel form of treatment for neuropsychiatric disorders, but little is known about the neurochemical mechanisms underlying the induction of lability, or destabilization, of a retrieved consolidated memory. Destabilization has been theoretically linked to the violation of expectations during memory retrieval, which, in turn, has been suggested to correlate with prediction error (PE). It is well-established that PE correlates with dopaminergic signaling in limbic forebrain structures that are critical for emotional learning. The basolateral amygdala is a key neural substrate for the reconsolidation of pavlovian reward-related memories, but the involvement of dopaminergic mechanisms in inducing lability of amygdala-dependent memories has not been investigated. Therefore, we tested the hypothesis that dopaminergic signaling within the basolateral amygdala is required for the destabilization of appetitive pavlovian memories by investigating the effects dopaminergic and protein synthesis manipulations on appetitive memory reconsolidation in rats. Intra-amygdala administration of either the D1-selective dopamine receptor antagonist SCH23390 or the D2-selective dopamine receptor antagonist raclopride prevented memory destabilization at retrieval, thereby protecting the memory from the effects of an amnestic agent, the protein synthesis inhibitor anisomycin. These data show that dopaminergic transmission within the basolateral amygdala is required for memory labilization during appetitive memory reconsolidation. PMID:26464966

  2. Growth and properties of crystalline barium oxide on the GaAs(100) substrate

    SciTech Connect

    Yasir, M.; Dahl, J.; Lång, J.; Tuominen, M.; Punkkinen, M. P. J.; Laukkanen, P. Kokko, K.; Kuzmin, M.; Korpijärvi, V.-M.; Polojärvi, V.; Guina, M.

    2013-11-04

    Growing a crystalline oxide film on III-V semiconductor renders possible approaches to improve operation of electronics and optoelectronics heterostructures such as oxide/semiconductor junctions for transistors and window layers for solar cells. We demonstrate the growth of crystalline barium oxide (BaO) on GaAs(100) at low temperatures, even down to room temperature. Photoluminescence (PL) measurements reveal that the amount of interface defects is reduced for BaO/GaAs, compared to Al{sub 2}O{sub 3}/GaAs, suggesting that BaO is a useful buffer layer to passivate the surface of the III-V device material. PL and photoemission data show that the produced junction tolerates the post heating around 600 °C.

  3. Impact of high-fat, low-carbohydrate diet on myocardial substrate oxidation, insulin sensitivity, and cardiac function after ischemia-reperfusion.

    PubMed

    Liu, Jian; Wang, Peipei; Douglas, Samuel L; Tate, Joshua M; Sham, Simon; Lloyd, Steven G

    2016-07-01

    High-fat, low-carbohydrate Diet (HFLCD) impairs the myocardial response to ischemia-reperfusion, but the underlying mechanisms remain elusive. We sought to determine the magnitude of diet-induced alterations in intrinsic properties of the myocardium (including insulin sensitivity and substrate oxidation) and circulating substrate and insulin differences resulting from diet, leading to this impaired response. Rats were fed HFLCD (60% kcal from fat/30% protein/10% carbohydrate) or control diet (CONT) (16%/19%/65%) for 2 wk. Isolated hearts underwent global low-flow ischemia followed by reperfusion (I/R). Carbon-13 NMR spectroscopy was used to determine myocardial substrate TCA cycle entry. Myocardial insulin sensitivity was assessed as dose-response of Akt phosphorylation. There was a significant effect of HFLCD and I/R with both these factors leading to an increase in free fatty acid (FFA) oxidation and a decrease in carbohydrate or ketone oxidation. Following I/R, HFLCD led to decreased ketone and increased FFA oxidation; the recovery of left ventricular (LV) function was decreased in HFLCD and was negatively correlated with FFA oxidation and positively associated with ketone oxidation. HFLCD also resulted in reduced insulin sensitivity. Under physiologic ranges, there were no direct effects of buffer insulin and ketone levels on oxidation of any substrate and recovery of cardiac function after I/R. An insulin-ketone interaction exists for myocardial substrate oxidation characteristics. We conclude that the impaired recovery of function after ischemia-reperfusion with HFLCD is largely due to intrinsic diet effects on myocardial properties, rather than to diet effect on circulating insulin or substrate levels. PMID:27199129

  4. Surface engineering of nanoporous substrate for solid oxide fuel cells with atomic layer-deposited electrolyte

    PubMed Central

    Ji, Sanghoon; Tanveer, Waqas Hassan; Yu, Wonjong; Kang, Sungmin; Cho, Gu Young; Kim, Sung Han

    2015-01-01

    Summary Solid oxide fuel cells with atomic layer-deposited thin film electrolytes supported on anodic aluminum oxide (AAO) are electrochemically characterized with varying thickness of bottom electrode catalyst (BEC); BECs which are 0.5 and 4 times thicker than the size of AAO pores are tested. The thicker BEC ensures far more active mass transport on the BEC side and resultantly the thicker BEC cell generates ≈11 times higher peak power density than the thinner BEC cell at 500 °C. PMID:26425432

  5. Surface engineering of nanoporous substrate for solid oxide fuel cells with atomic layer-deposited electrolyte.

    PubMed

    Ji, Sanghoon; Tanveer, Waqas Hassan; Yu, Wonjong; Kang, Sungmin; Cho, Gu Young; Kim, Sung Han; An, Jihwan; Cha, Suk Won

    2015-01-01

    Solid oxide fuel cells with atomic layer-deposited thin film electrolytes supported on anodic aluminum oxide (AAO) are electrochemically characterized with varying thickness of bottom electrode catalyst (BEC); BECs which are 0.5 and 4 times thicker than the size of AAO pores are tested. The thicker BEC ensures far more active mass transport on the BEC side and resultantly the thicker BEC cell generates ≈11 times higher peak power density than the thinner BEC cell at 500 °C. PMID:26425432

  6. Enhancement of Characteristics of Transparent Conductive Electrode on Flexible Substrate by Combination of Solution-Based Oxide and Metallic Layers.

    PubMed

    Hong, Sung-Jei; Kim, Yong-Hoon; Cha, Seung-Jae; Kim, Yong-Sung

    2015-10-01

    This study investigates solution-processed transparent conductors with hybrid structure consisting of silver nanowires (AgNWs) and indium-tin-oxide nanoparticles (ITO-NPs) layers fabricated on polymeric flexible polyethylene terephthalate (PET) substrate. The transparent conductors had stacked structures of AgNWs/ITO-NPs on 125-μm-thick PET and ITO-NPs/AgNWs/ITO-NPs on 125-μm-thick PET, 188-μm-thick PET, or 700-μm-thick glass substrate, respectively. Successful integrations were possible on the substrates without any deformation or distortion. Sheet resistance of the triple-layered transparent conductor samples exhibits low values ranging from 22.41 Ω/square to 22.99 Ω/squarer. Also, their optical transmittance exhibits high values ranging from 83.78 to 87.29% at 550 nm. The triple-layered transparent conductor showed a good thermal stability in terms of sheet resistance and optical transmittance against the high-temperature environment up to 250 °C. All the double and triple-layered transparent conductors fabricated on PET and glass substrates are so stable against the accelerated thermal aging from 110 °C to 130 °C, that ΔR/R0 and ΔT(550)/T0(550) values exhibit less than 0.068 and 0.049, respectively. Furthermore, the layers are so flexible that ΔR/R0 of the layers on PET substrates is lower than 0.1 even at 4.0-mm bending. Especially, triple-layered transparent conductor on 125-μm-thick PET substrates exhibits ΔR/R0 value of 0.042 even at 4.0 mm bending. Thus, it can be concluded that the hybrid structures have the advantage of both thermal stability and flexibility for electrical and optical properties of transparent conductive electrode; which makes them highly applicable in flexible electronics. PMID:26726453

  7. Solution-processed indium-tin-oxide nanoparticle transparent conductors on flexible glass substrate with high optical transmittance and high thermal stability

    NASA Astrophysics Data System (ADS)

    Hong, Sung-Jei; Kim, Sun-Woo; In Han, Jeong

    2014-08-01

    In this study, solution-processed transparent conductors on flexible glass substrate were investigated using indium-tin-oxide (ITO) nanoparticle (NP) ink. The ITO-NP conductors were well fabricated on the flexible glass substrate with neither distortion nor deformation. Optical transmittances of the ITO-NP conductors on flexible glass substrate were enhanced to more than 91% that is higher than those on rigid glass substrate owing to decreased thickness. As well, the ITO-NP conductors on flexible glass substrate heat-treated at 500 and 600 °C showed good thermal stabilities of electrical and optical properties. In case of bending characteristics of samples heat-treated at 500 and 600 °C, the change in resistance was slight within 14%, which is smaller than those of conventional TCOs on flexible films. Based on the results, we propose that the solution-processed ITO-NP conductors are suitable for TCOs on flexible glass substrates.

  8. Increased cell survival of cells exposed to superparamagnetic iron oxide nanoparticles through biomaterial substrate-induced autophagy.

    PubMed

    Tseng, Ting-Chen; Hsieh, Fu-Yu; Hsu, Shan-Hui

    2016-04-22

    The cellular uptake of nanoparticles (NPs) can be promoted by NP surface modification but cell viability is often sacrificed. Our previous study has shown that intracellular uptake of iron oxide NPs was significantly increased for cells cultured on chitosan. However, the mechanism for having the higher cellular uptake as well as better cell survival on the chitosan surface remains unclear. In this study, we sought to clarify if the autophagic response may contribute to cell survival under excessive NP exposure conditions on chitosan. L929 fibroblasts and neural stem cells (NSCs) were challenged with different concentrations (0-300 μg ml(-1)) of superparamagnetic iron oxide NPs. The autophagic response as well as the metabolic activity of cells was evaluated. Results showed that culturing both types of cells on chitosan substrates significantly enhanced the cellular uptake of NPs. At higher NP concentrations, cells on chitosan showed a greater survival rate than those on TCPS. The expression levels of autophagy-related genes (Atg5 and Atg7 genes) and autophagy associated protein (LC3-II) on chitosan were higher than that on TCPS. The NP exposure further increased the expressions. We suggest that cells cultured on chitosan were more tolerant to NP cytotoxicity because of the increased autophagic response. Moreover, NP exposure increased the metabolic activity of cells grown on chitosan, while it decreased the metabolism of cells cultured on TCPS. In animal studies, iron oxide-labeled NSCs were injected in zebrafish embryos. Results also showed that cells grown on chitosan had better survival after transplantation than those grown on TCPS. Taken together, chitosan as a culture substrate can induce cell autophagy to increase cell survival in particular for NP-labeled cells. This will be valuable for the biomedical application of NPs in cell therapy. PMID:26815305

  9. Appetitive floral odours prevent aggression in honeybees

    PubMed Central

    Nouvian, Morgane; Hotier, Lucie; Claudianos, Charles; Giurfa, Martin; Reinhard, Judith

    2015-01-01

    Honeybees defend their colonies aggressively against intruders and release a potent alarm pheromone to recruit nestmates into defensive tasks. The effect of floral odours on this behaviour has never been studied, despite the relevance of these olfactory cues for the biology of bees. Here we use a novel assay to investigate social and olfactory cues that drive defensive behaviour in bees. We show that social interactions are necessary to reveal the recruiting function of the alarm pheromone and that specific floral odours—linalool and 2-phenylethanol—have the surprising capacity to block recruitment by the alarm pheromone. This effect is not due to an olfactory masking of the pheromone by the floral odours, but correlates with their appetitive value. In addition to their potential applications, these findings provide new insights about how honeybees make the decision to engage into defence and how conflicting information affects this process. PMID:26694599

  10. Appetitive floral odours prevent aggression in honeybees.

    PubMed

    Nouvian, Morgane; Hotier, Lucie; Claudianos, Charles; Giurfa, Martin; Reinhard, Judith

    2015-01-01

    Honeybees defend their colonies aggressively against intruders and release a potent alarm pheromone to recruit nestmates into defensive tasks. The effect of floral odours on this behaviour has never been studied, despite the relevance of these olfactory cues for the biology of bees. Here we use a novel assay to investigate social and olfactory cues that drive defensive behaviour in bees. We show that social interactions are necessary to reveal the recruiting function of the alarm pheromone and that specific floral odours-linalool and 2-phenylethanol-have the surprising capacity to block recruitment by the alarm pheromone. This effect is not due to an olfactory masking of the pheromone by the floral odours, but correlates with their appetitive value. In addition to their potential applications, these findings provide new insights about how honeybees make the decision to engage into defence and how conflicting information affects this process. PMID:26694599

  11. Effects of sputtering power on properties of copper oxides thin films deposited on glass substrates

    SciTech Connect

    Ooi, P. K.; Ng, S. S.; Abdullah, M. J.

    2015-04-24

    Copper oxides are deposited by radio frequency sputtering using copper target in the mixture of argon and oxygen gasses. The structural and optical properties of the copper oxides deposited at different sputtering powers have been investigated. All the films are single phase polycrystalline. At low RF power (100 W), the film is monoclinic structure of cupric oxide (CuO). Meanwhile, the films are cubic structure of cuprous oxide (Cu2O) at higher RF power. Field emission scanning electron microscopy images show the films have different morphologies with small grain size and consist of a lot of voids. The analysis of energy dispersive X-ray spectroscopy shows that the ratio of Cu to O is increased as the RF power increased. From the ultraviolet–visible spectroscopy, the films have a broad absorption edge in the range of 300–500 nm. The band gap of the films grown at RF power of 100 W, and 120 W and above, were 1.18 eV and 2.16 eV, respectively.

  12. Genetics of Amino Acid Taste and Appetite.

    PubMed

    Bachmanov, Alexander A; Bosak, Natalia P; Glendinning, John I; Inoue, Masashi; Li, Xia; Manita, Satoshi; McCaughey, Stuart A; Murata, Yuko; Reed, Danielle R; Tordoff, Michael G; Beauchamp, Gary K

    2016-07-01

    The consumption of amino acids by animals is controlled by both oral and postoral mechanisms. We used a genetic approach to investigate these mechanisms. Our studies have shown that inbred mouse strains differ in voluntary amino acid consumption, and these differences depend on sensory and nutritive properties of amino acids. Like humans, mice perceive some amino acids as having a sweet (sucrose-like) taste and others as having an umami (glutamate-like) taste. Mouse strain differences in the consumption of some sweet-tasting amino acids (d-phenylalanine, d-tryptophan, and l-proline) are associated with polymorphisms of a taste receptor, type 1, member 3 gene (Tas1r3), and involve differential peripheral taste responsiveness. Strain differences in the consumption of some other sweet-tasting amino acids (glycine, l-alanine, l-glutamine, and l-threonine) do not depend on Tas1r3 polymorphisms and so must be due to allelic variation in other, as yet unknown, genes involved in sweet taste. Strain differences in the consumption of l-glutamate may depend on postingestive rather than taste mechanisms. Thus, genes and physiologic mechanisms responsible for strain differences in the consumption of each amino acid depend on the nature of its taste and postingestive properties. Overall, mouse strain differences in amino acid taste and appetite have a complex genetic architecture. In addition to the Tas1r3 gene, these differences depend on other genes likely involved in determining the taste and postingestive effects of amino acids. The identification of these genes may lead to the discovery of novel mechanisms that regulate amino acid taste and appetite. PMID:27422518

  13. Fabrication and characterization of ZnO nanowires by wet oxidation of Zn thin film deposited on Teflon substrate

    NASA Astrophysics Data System (ADS)

    Farhat, O. F.; Halim, M. M.; Abdullah, M. J.; Ali, M. K. M.; Ahmed, Naser M.; Bououdina, M.

    2015-10-01

    In this study, ZnO nanowires (NWs) were successfully grown for the first time on to Teflon substrate by a wet oxidation of a Zn thin film coated by RF sputtering technique. The sputtered Zn thin film was oxidized at 100 °C for 5 h under water-vapour using a horizontal furnace. This oxidation process transformed Zn thin film into ZnO with wire-like nanostructure. XRD analysis confirms the formation of single nanocrystalline ZnO phase having a low compressive strain. FESEM observations reveal high density of ZnO NWs with diameter ranging from 34 to 52 nm and length about 2.231 μm, which are well distributed in different direction. A flexible ZnO NWs-based metal-semiconductor-metal UV photodetector was fabricated. Photo-response and sensitivity measurements under low power illumination (375 nm, 1.5 mW/cm2) showed a high sensitivity of 2050%, which can be considered a relatively fast response and baseline recovery for UV detection.

  14. Alcohol gains access to appetitive learning through adolescent heavy drinking.

    PubMed

    DiLeo, Alyssa; Wright, Kristina M; Mangone, Elizabeth; McDannald, Michael A

    2015-08-01

    Adolescent heavy alcohol drinking increases the risk for alcohol use disorders in adulthood, yet mechanisms conferring increased risk are not well understood. We propose that adolescent alcohol drinking shapes alcohol's aversive or appetitive properties in adulthood. Alcohol normally drives aversive learning and alcohol-predictive cues are avoided. We hypothesize that through adolescent heavy drinking alcohol gains access to appetitive learning. A primary consequence is that alcohol-predictive cues become valued and sought out. To test this hypothesis, we gave genetically heterogeneous, male Long Evans rats voluntary, chronic intermittent access to water or alcohol throughout adolescence and then identified moderate and heavy alcohol drinkers. After a short abstinence period, we assessed the aversive or appetitive properties of alcohol using flavor learning procedures. We compared alcohol to the known appetitive properties of sugar. Flavor learning in adult rats who were alcohol-naïve or adolescent moderate alcohol drinkers revealed alcohol to be aversive and sugar to be appetitive. The same flavor learning procedures revealed both alcohol and sugar to be appetitive in adult rats who were adolescent heavy drinkers. The results demonstrate that alcohol gains access to neurobehavioral circuits for appetitive learning through adolescent heavy alcohol drinking. PMID:26052793

  15. Alcohol gains access to appetitive learning through adolescent heavy drinking

    PubMed Central

    DiLeo, Alyssa; Wright, Kristina M.; Mangone, Elizabeth; McDannald, Michael A.

    2015-01-01

    Adolescent heavy alcohol drinking increases the risk for alcohol use disorders in adulthood, yet mechanisms conferring increased risk are not well understood. We propose that adolescent alcohol drinking shapes alcohol’s aversive or appetitive properties in adulthood. Alcohol normally drives aversive learning and alcohol-predictive cues are avoided. We hypothesize that through adolescent heavy drinking alcohol gains access to appetitive learning. A primary consequence is that alcohol-predictive cues become valued and sought out. To test this hypothesis, we gave genetically heterogeneous, male Long Evans rats voluntary, chronic intermittent access to water or alcohol throughout adolescence and then identified moderate and heavy alcohol drinkers. After a short abstinence period, we assessed the aversive or appetitive properties of alcohol using flavor learning procedures. We compared alcohol to the known appetitive properties of sugar. Flavor learning in adult rats who were alcohol-naïve or adolescent moderate alcohol drinkers revealed alcohol to be aversive and sugar to be appetitive. The same flavor learning procedures revealed both alcohol and sugar to be appetitive in adult rats who were adolescent heavy drinkers. The results demonstrate that alcohol gains access to neurobehavioral circuits for appetitive learning through adolescent heavy alcohol drinking. PMID:26052793

  16. Stability Comparison of Perovskite Solar Cells Based on Zinc Oxide and Titania on Polymer Substrates.

    PubMed

    Dkhissi, Yasmina; Meyer, Steffen; Chen, Dehong; Weerasinghe, Hasitha C; Spiccia, Leone; Cheng, Yi-Bing; Caruso, Rachel A

    2016-04-01

    Device scale-up and long-term stability constitute two major hurdles that the emerging perovskite solar technology will have to overcome before commercialization. Here, a comparative study was performed between ZnO and TiO2 electron-selective layers, two materials that allow the low-temperature processing of perovskite solar cells on polymer substrates. Although the use of TiO2 is well established on glass substrates, ZnO was chosen because it can be readily printed at low temperature and offers the potential for the large-scale roll-to-roll manufacturing of flexible photovoltaics at a low cost. However, a rapid degradation of CH3 NH3 PbI3 was observed if it was deposited on ZnO, therefore, the influence of the perovskite film preparation conditions on its morphology and degradation kinetics was investigated. This study showed that CH3 NH3 PbI3 could withstand a higher temperature on TiO2 than ZnO and that TiO2 -based perovskite devices were more stable than their ZnO analogues. PMID:26893225

  17. Effect of Oxidation Temperature on Physical and Electrical Properties of Sm2O3 Thin-Film Gate Oxide on Si Substrate

    NASA Astrophysics Data System (ADS)

    Goh, Kian Heng; Haseeb, A. S. M. A.; Wong, Yew Hoong

    2016-06-01

    Thermal oxidation of 150-nm sputtered pure samarium metal film on silicon substrate has been carried out in oxygen ambient at various temperatures (600°C to 900°C) for 15 min and the effect of the oxidation temperature on the structural, chemical, and electrical properties of the resulting Sm2O3 layers investigated. The crystallinity of the Sm2O3 films and the existence of an interfacial layer were evaluated by x-ray diffraction (XRD) analysis, Fourier-transform infrared (FTIR) spectroscopy, and Raman analysis. The crystallite size and microstrain of Sm2O3 were estimated by Williamson-Hall (W-H) plot analysis, with comparison of the former with the crystallite size of Sm2O3 as calculated using the Scherrer equation. High-resolution transmission electron microscopy (HRTEM) with energy-dispersive x-ray (EDX) spectroscopy analysis was carried out to investigate the cross-sectional morphology and chemical distribution of selected regions. The activation energy or growth rate of each stacked layer was calculated from Arrhenius plots. The surface roughness and topography of the Sm2O3 layers were examined by atomic force microscopy (AFM) analysis. A physical model based on semipolycrystalline nature of the interfacial layer is suggested and explained. Results supporting such a model were obtained by FTIR, XRD, Raman, EDX, and HRTEM analyses. Electrical characterization revealed that oxidation temperature at 700°C yielded the highest breakdown voltage, lowest leakage current density, and highest barrier height value.

  18. Marine sediments microbes capable of electrode oxidation as a surrogate for lithotrophic insoluble substrate metabolism

    PubMed Central

    Rowe, Annette R.; Chellamuthu, Prithiviraj; Lam, Bonita; Okamoto, Akihiro; Nealson, Kenneth H.

    2015-01-01

    Little is known about the importance and/or mechanisms of biological mineral oxidation in sediments, partially due to the difficulties associated with culturing mineral-oxidizing microbes. We demonstrate that electrochemical enrichment is a feasible approach for isolation of microbes capable of gaining electrons from insoluble minerals. To this end we constructed sediment microcosms and incubated electrodes at various controlled redox potentials. Negative current production was observed in incubations and increased as redox potential decreased (tested −50 to −400 mV vs. Ag/AgCl). Electrode-associated biomass responded to the addition of nitrate and ferric iron as terminal electron acceptors in secondary sediment-free enrichments. Elemental sulfur, elemental iron and amorphous iron sulfide enrichments derived from electrode biomass demonstrated products indicative of sulfur or iron oxidation. The microbes isolated from these enrichments belong to the genera Halomonas, Idiomarina, Marinobacter, and Pseudomonas of the Gammaproteobacteria, and Thalassospira and Thioclava from the Alphaproteobacteria. Chronoamperometry data demonstrates sustained electrode oxidation from these isolates in the absence of alternate electron sources. Cyclic voltammetry demonstrated the variability in dominant electron transfer modes or interactions with electrodes (i.e., biofilm, planktonic or mediator facilitated) and the wide range of midpoint potentials observed for each microbe (from 8 to −295 mV vs. Ag/AgCl). The diversity of extracellular electron transfer mechanisms observed in one sediment and one redox condition, illustrates the potential importance and abundance of these interactions. This approach has promise for increasing our understanding the extent and diversity of microbe mineral interactions, as well as increasing the repository of microbes available for electrochemical applications. PMID:25642220

  19. Development of Oxidation Resistant Coatings on GRCop-84 Substrates by Cold Spray Process

    NASA Technical Reports Server (NTRS)

    Karthikeyan, J.

    2007-01-01

    GRCop-84, a Cu-CR-Nb alloy, has been developed for rocket engine liner applications. For maximum life additional oxidation protection is required to prevent blanching. NiCrAlY was identified as a suitable coating, and efforts were initiated to develop suitable coating techniques. Cold spray is one technique under consideration. Efforts at ASB Industries to produce dense, adherent coatings are detailed. The work culminated in the production of samples for testing at NASA Glenn Research Center.

  20. Air, aqueous and thermal stabilities of Ce3+ ions in cerium oxide nanoparticle layers with substrates.

    PubMed

    Naganuma, Tamaki; Traversa, Enrico

    2014-06-21

    Abundant oxygen vacancies coexisting with Ce(3+) ions in fluorite cerium oxide nanoparticles (CNPs) have the potential to enhance catalytic ability, but the ratio of unstable Ce(3+) ions in CNPs is typically low. Our recent work, however, demonstrated that the abundant Ce(3+) ions created in cerium oxide nanoparticle layers (CNPLs) by Ar ion irradiation were stable in air at room temperature. Ce valence states in CNPs correlate with the catalytic ability that involves redox reactions between Ce(3+) and Ce(4+) ions in given application environments (e.g. high temperature in carbon monoxide gas conversion and immersion conditions in biomedical applications). To better understand the mechanism by which Ce(3+) ions achieve stability in CNPLs, we examined (i) extra-long air-stability, (ii) thermal stability up to 500 °C, and (iii) aqueous stability of Ce(3+) ions in water, buffer solution and cell culture medium. It is noteworthy that air-stability of Ce(3+) ions in CNPLs persisted for more than 1 year. Thermal stability results showed that oxidation of Ce(3+) to Ce(4+) occurred at 350 °C in air. Highly concentrated Ce(3+) ions in ultra-thin CNPLs slowly oxidized in water within 1 day, but stability was improved in the cell culture medium. Ce(3+) stability of CNPLs immersed in the medium was associated with phosphorus adsorption on the Ce(3+) sites. This study also illuminates the potential interaction mechanisms of stable Ce(3+) ions in CNPLs. These findings could be utilized to understand catalytic mechanisms of CNPs with abundant oxygen vacancies in their application environments. PMID:24812662

  1. Marine sediments microbes capable of electrode oxidation as a surrogate for lithotrophic insoluble substrate metabolism.

    PubMed

    Rowe, Annette R; Chellamuthu, Prithiviraj; Lam, Bonita; Okamoto, Akihiro; Nealson, Kenneth H

    2014-01-01

    Little is known about the importance and/or mechanisms of biological mineral oxidation in sediments, partially due to the difficulties associated with culturing mineral-oxidizing microbes. We demonstrate that electrochemical enrichment is a feasible approach for isolation of microbes capable of gaining electrons from insoluble minerals. To this end we constructed sediment microcosms and incubated electrodes at various controlled redox potentials. Negative current production was observed in incubations and increased as redox potential decreased (tested -50 to -400 mV vs. Ag/AgCl). Electrode-associated biomass responded to the addition of nitrate and ferric iron as terminal electron acceptors in secondary sediment-free enrichments. Elemental sulfur, elemental iron and amorphous iron sulfide enrichments derived from electrode biomass demonstrated products indicative of sulfur or iron oxidation. The microbes isolated from these enrichments belong to the genera Halomonas, Idiomarina, Marinobacter, and Pseudomonas of the Gammaproteobacteria, and Thalassospira and Thioclava from the Alphaproteobacteria. Chronoamperometry data demonstrates sustained electrode oxidation from these isolates in the absence of alternate electron sources. Cyclic voltammetry demonstrated the variability in dominant electron transfer modes or interactions with electrodes (i.e., biofilm, planktonic or mediator facilitated) and the wide range of midpoint potentials observed for each microbe (from 8 to -295 mV vs. Ag/AgCl). The diversity of extracellular electron transfer mechanisms observed in one sediment and one redox condition, illustrates the potential importance and abundance of these interactions. This approach has promise for increasing our understanding the extent and diversity of microbe mineral interactions, as well as increasing the repository of microbes available for electrochemical applications. PMID:25642220

  2. Immobilization of iron oxide nanoclusters on surface functionalized silicon substrate and their catalytic behavior to synthesize multi-walled carbon nanotubes.

    PubMed

    Adhikari, Prashanta Dhoj; Kim, Sunghwan; Lee, Sui; Park, Chong-Yun

    2013-07-01

    Multi-walled carbon nanotubes (MWCNTs) were grown using iron oxide nanoclusters (Nc) assisted by self-assembled monolayer (SAM) on substrate. The amine-terminated SAM fabricated on silicon substrate (APTMS/SI) was carried out by UV-treatment and immersed into the FeCI3/HCI aqueous solution. Then, Nc were immobilized onto oxidized SAM silicon substrate (SAMs/Si) through electrostatic interaction between cationic Nc and anionic SAMs/Si. The characterization results clearly show that the well-graphitized MWCNTs were synthesized by using functionalized silicon substrate (Nc/SAMs/Si) as a template having appropriate density of catalyst. These consequences show that SAM containing template is important to achieve the effective layer of catalyst to synthesize MWCNTs in chemical vapor deposition (CVD). PMID:23901478

  3. Epitaxial iron oxide nanocrystals with memory function grown on Si substrates

    NASA Astrophysics Data System (ADS)

    Ishibe, Takafumi; Matsui, Hideki; Watanabe, Kentaro; Takeuchi, Shotaro; Sakai, Akira; Nakamura, Yoshiaki

    2016-05-01

    High-density Fe3O4‑δ nanocrystals (NCs) were epitaxially grown on Si substrates by molecular beam epitaxy with epitaxial Ge NCs being used as nucleation sites. Scanning tunneling spectroscopy measurements showed that the surface bandgap of the as-grown Fe3O4‑δ NCs was ∼0.2 eV, consistent with that reported for Fe3O4‑δ films. Conductive atomic force microscopy measurements of the NCs revealed hysteresis in the voltage–current curves, indicating bipolar resistive switching behavior. The measurement results established the superiority of the NCs to thin conventional polycrystalline Fe3O4‑δ films/Si in terms of resistive switching characteristics. This demonstrated the possibility of developing resistance random access memory devices composed of ubiquitous Fe3O4‑δ NC materials.

  4. Synthesis, characterization, structural, and optical properties of zinc oxide nanostructures embedded in silicon based substrates

    NASA Astrophysics Data System (ADS)

    Pandey, Bimal

    Structural and optical properties of ZnO nanostructures synthesized by low energy ion implantation technique were examined. ZnO molecular ions were implanted into Si/SiO2 substrates at room temperature and then furnace annealed under different temperatures and environments. In all as-implanted samples only Zn nanostructures with varying diameters distributed into the Si/SiO2 matrices were observed. No trace of ZnO was found. The distributions of Zn nanostructures in Si/SiO2 closely matched results from Stopping and Range of Ions in Matter (SRIM) simulations. During annealing at 750 °C, Zn diffused both toward and away from the surface of the substrate and combine with oxygen to form ZnO nanostructures. At higher annealing temperatures ZnO bonding started to break down and transfer to zinc silicate (Zn2SiO4), and at 900 °C the ZnO was completely converted into Zn2SiO4. The average sizes of Zn/ZnO nanostructures depended on the ion fluence. If the fluence increased the average sizes of nanostructures also increased and vice versa. For room temperature photoluminescence (RT-PL), band-edge emission in the ultraviolet (UV) region was observed from all samples annealed at 700 °C/750 °C and were slightly blue shifted as compare to bulk ZnO. Donor-bound exciton (D,X) and acceptor-bound exciton (A,X) transitions were observed in low temperature photoluminescence (PL). The lifetime of both donor-bound excitonic emission (D, X) and acceptor-bound excitonic emission (A, X) were found to be in the picosecond (ps) range.

  5. Ceria catalyst for inert-substrate-supported tubular solid oxide fuel cells running on methane fuel

    NASA Astrophysics Data System (ADS)

    Zhao, Kai; Kim, Bok-Hee; Du, Yanhai; Xu, Qing; Ahn, Byung-Guk

    2016-05-01

    A ceria catalyst is applied to an inert-substrate supported tubular single cell for direct operation on methane fuel. The tubular single cell comprises a porous yttria-stabilized zirconia (YSZ) supporter, a Ni-Ce0.8Sm0.2O1.9 anode, a YSZ/Ce0.8Sm0.2O1.9 bi-layer electrolyte, and a La0.6Sr0.4Co0.2Fe0.8O3-δ cathode. The ceria catalyst is incorporated into the porous YSZ supporter layer by a cerium nitrate impregnation. The effects of ceria on the microstructure and electrochemical performance of the tubular single cell are investigated with respect to the number of impregnations. The optimum number of impregnations is determined to be four based on the maximum power density and polarization property of the tubular single cell in hydrogen and methane fuels. At 700 °C, the tubular single cell shows similar maximum power densities of ∼260 mW cm-2 in hydrogen and methane fuels, respectively. Moreover, the ceria catalyst significantly improves the performance stability of the cell running on methane fuel. At a current density of 350 mA cm-2, the single cell shows a low degradation rate of 2.5 mV h-1 during the 13 h test in methane fuel. These results suggest the feasibility of applying the ceria catalyst to the inert-substrate supported tubular single cell for direct operation on methane fuel.

  6. Effect of time and of precursor molecule on the deposition of hydrophobic nanolayers on ethyelene tetrafluoroethylene-silicon oxide substrates

    NASA Astrophysics Data System (ADS)

    Rossi, Gabriella; Castellano, Piera; Incarnato, Loredana

    2016-01-01

    A method was developed for generating transparent and hydrophobic nanolayers chemisorbed onto flexible substrates of ethylene tetrafluoroethylene-silicon oxide (ETFE-SiOx). In particular, the effect of the deposition time and of the precursor molecule on the nanocoating process was analyzed with the aim of pursuing an optimization of the above method in an industrial application perspective. It was found that precursor molecule of triethoxysilane allowed to obtain better hydrophobic properties on the SiOx surface in shorter times compared to trichlorosilane, reaching the 92 % of final contact angle (CA) value of 106° after only 1 h of deposition. The optical properties and surface morphology were also assessed in function of time, revealing that an initial transparency reduction is followed by a subsequent transmittance increase during the self assembly of fluoroalkylsilanes on the SiOx surface, coherently with the surface roughness analysis data. Encouraging results were also obtained in terms of oleophobic properties improvement of the nanocoated surfaces.

  7. Magneto-transport properties of oriented Mn{sub 2}CoAl films sputtered on thermally oxidized Si substrates

    SciTech Connect

    Xu, G. Z.; Du, Y.; Zhang, X. M.; Liu, E. K.; Wang, W. H. Wu, G. H.; Zhang, H. G.

    2014-06-16

    Spin gapless semiconductors are interesting family of materials by embracing both magnetism and semiconducting due to their unique band structure. Its potential application in future spintronics requires realization in thin film form. In this Letter, we report fabrication and transport properties of spin gapless Mn{sub 2}CoAl films prepared on thermally oxidized Si substrates by magnetron sputtering deposition. The films deposited at 673 K are well oriented to (001) direction and display a uniform-crystalline surface. Magnetotransport measurements on the oriented films reveal a semiconducting-like resistivity, small anomalous Hall conductivity, and linear magnetoresistance representative of the transport signatures of spin gapless semiconductors. The magnetic properties of the films have also been investigated and compared to that of bulk Mn{sub 2}CoAl, showing small discrepancy induced by the composition deviation.

  8. Enhanced field emission properties from well-aligned zinc oxide nanoneedles grown on the Au/Ti/n-Si substrate

    SciTech Connect

    Park, Chan Jun; Choi, Duck-Kyun; Yoo, Jinkyoung; Yi, Gyu-Chul; Lee, Cheol Jin

    2007-02-19

    The authors investigated the field emission from vertically well-aligned zinc oxide (ZnO) nanoneedles grown on the Au/Ti/n-Si (100) substrate using metal organic chemical vapor deposition. The turn-on field of ZnO nanoneedles was about 0.85 V/{mu}m at the current density of 0.1 {mu}A/cm{sup 2}, and the emission current density of 1 mA/cm{sup 2} was achieved at the applied electric field of 5.0 V/{mu}m. The low turn-on field of the ZnO nanoneedles was attributed to very sharp tip morphology, and the high emission current density was mainly caused by the formation of the stable Ohmic contact between the ZnO nanoneedles and Au film.

  9. Formation of oxides and their role in the growth of Ag nanoplates on GaAs substrates.

    SciTech Connect

    Sun, Y.; Gosztola, D.; Lei, C.; Haasch, R.; Center for Nanoscale Materials; Univ. of Illinois

    2008-10-21

    Simple galvanic reactions between highly doped n-type GaAs wafers and a pure aqueous solution of AgNO3 at room temperature provide an easy and efficient protocol to directly deposit uniform Ag nanoplates with tunable dimensions on the GaAs substrates. The anisotropic growth of the Ag nanoplates in the absence of surfactant molecules might be partially ascribed to the codeposition of oxides of gallium and arsenic, which are revealed by extensive data from electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy, during the growth of the Ag nanoplates. The electron microscopic characterization shows that each Ag nanoplate has a 'necked' geometry, that is, it pins on the GaAs lattices through only a tiny neck (with sizes of <10 nm). In addition, the as-grown Ag nanoplates exhibit strong enhancement toward Raman scattering of materials on (or around) their surfaces.

  10. Substrate Fermi level effects in photocatalysis on oxides: Properties of ultrathin TiO2/Si films

    NASA Astrophysics Data System (ADS)

    Kazazis, D.; Guha, S.; Bojarczuk, N. A.; Zaslavsky, A.; Kim, H.-C.

    2009-08-01

    Photocatalysis has widespread applications from solar cells to photolithography. We studied the photocatalytic properties of TiO2 films of thicknesses down to 2 nm, grown on n-type and p-type silicon wafers, using the oxidation of isopropanol as a model system. Direct in vacuo mass spectrometry measurements were performed under irradiation above the TiO2 bandgap. We present a model consistent with our experimental results, which indicate that only near-surface electron-hole pair generation is relevant and that the reaction rate can be controlled by varying the substrate Fermi level in going from n-type to p-type silicon, by approximately a factor of 2.

  11. Surface studies on aluminized and thermally oxidized superalloy 690 substrates interacted with simulated nuclear waste and sodium borosilicate melt

    NASA Astrophysics Data System (ADS)

    Yusufali, C.; Kshirsagar, R. J.; Mishra, R. K.; Kaushik, C. P.; Sengupta, P.; Dutta, R. S.; Dey, G. K.

    2014-04-01

    Aluminized and thermally oxidized Ni-Cr-Fe based superalloy 690 substrates with Al2O3 layer on top have been exposed in nitrate based environment (simulated high level nuclear liquid waste) at 373 K for 216 hours and sodium borosilicate melt at 1248 K for 192 hours. The surfaces of exposed samples have been characterized by using Electron probe micro-analyzer (EPMA). Elemental X-ray mapping on coated specimen that exposed in simulated nuclear waste solution revealed that the surface is enriched with Ni, Cr and Al. X-ray mapping on surface of the specimen that interacted with sodium borosilicate melt indicated that the surface is composed of Al, Fe, Ni and Cr.

  12. Flexible nickel-doped zinc oxide thin-film transistors fabricated on plastic substrates at low temperature

    NASA Astrophysics Data System (ADS)

    Huang, Lingling; Han, Dedong; Chen, Zhuofa; Cong, Yingying; Wu, Jing; Zhao, Nannan; Dong, Junchen; Zhao, Feilong; Liu, Lifeng; Zhang, Shengdong; Zhang, Xing; Wang, Yi

    2015-04-01

    High-performance nickel (Ni)-doped zinc oxide thin-film transistors (NZO TFTs) have been successfully fabricated on transparent flexible plastic substrates at a low temperature. The effect of different oxygen partial pressures during channel deposition on the electrical properties of NZO TFTs was studied to improve the device performance. We found that the oxygen partial pressure during channel deposition has a significant influence on the performance of NZO TFTs. Finally, it was demonstrated that a NZO film with 100% Ar sputtering gas during channel deposition exhibited the best electrical properties, with a drain current on/off ratio of 108, a positive threshold voltage of 2.59 V, a subthreshold swing of 233 mV/decade, and a saturation mobility of 118.9 cm2·V-1·s-1. The results show that Ni-doped ZnO is a promising candidate for flexible fully transparent displays.

  13. Surface studies on aluminized and thermally oxidized superalloy 690 substrates interacted with simulated nuclear waste and sodium borosilicate melt

    SciTech Connect

    Yusufali, C. Sengupta, P.; Dutta, R. S.; Dey, G. K.; Kshirsagar, R. J.; Mishra, R. K.; Kaushik, C. P.

    2014-04-24

    Aluminized and thermally oxidized Ni-Cr-Fe based superalloy 690 substrates with Al{sub 2}O{sub 3} layer on top have been exposed in nitrate based environment (simulated high level nuclear liquid waste) at 373 K for 216 hours and sodium borosilicate melt at 1248 K for 192 hours. The surfaces of exposed samples have been characterized by using Electron probe micro-analyzer (EPMA). Elemental X-ray mapping on coated specimen that exposed in simulated nuclear waste solution revealed that the surface is enriched with Ni, Cr and Al. X-ray mapping on surface of the specimen that interacted with sodium borosilicate melt indicated that the surface is composed of Al, Fe, Ni and Cr.

  14. Effect of Fe coating of nucleation sites on epitaxial growth of Fe oxide nanocrystals on Si substrates

    NASA Astrophysics Data System (ADS)

    Ishibe, Takafumi; Watanabe, Kentaro; Nakamura, Yoshiaki

    2016-08-01

    We studied the effect of Fe coating on the epitaxial growth of Fe3O4 nanocrystals (NCs) over Fe-coated Ge epitaxial nuclei on Si(111). To completely cover Ge nuclei with Fe, some amount of Fe (>8 monolayers) must be deposited. Such covering is a key to epitaxial growth because an Fe coating layer prevents the oxidation of Ge surfaces during Fe3O4 formation, resulting in the epitaxial growth of Fe3O4 on them. This study demonstrates that an appropriate Fe coating of nucleation sites leads to the epitaxial growth of Fe3O4 NCs on Si substrates, indicating the realization of environmentally friendly and low-cost Fe3O4 NCs as the resistance random access memory material.

  15. Toward Plastic Smart Windows: Optimization of Indium Tin Oxide Electrodes for the Synthesis of Electrochromic Devices on Polycarbonate Substrates.

    PubMed

    Laurenti, Marco; Bianco, Stefano; Castellino, Micaela; Garino, Nadia; Virga, Alessandro; Pirri, Candido F; Mandracci, Pietro

    2016-03-01

    Plastic smart windows are becoming one of the key elements in view of the fabrication of inexpensive, lightweight electrochromic (EC) devices to be integrated in the new generation of high-energy-efficiency buildings and automotive applications. However, fabricating electrochromic devices on polymer substrates requires a reduction of process temperature, so in this work we focus on the development of a completely room-temperature deposition process aimed at the preparation of ITO-coated polycarbonate (PC) structures acting as transparent and conductive plastic supports. Without providing any substrate heating or surface activation pretreatments of the polymer, different deposition conditions are used for growing indium tin oxide (ITO) thin films by the radiofrequency magnetron sputtering technique. According to the characterization results, the set of optimal deposition parameters is selected to deposit ITO electrodes having high optical transmittance in the visible range (∼90%) together with low sheet resistance (∼8 ohm/sq). The as-prepared ITO/PC structures are then successfully tested as conductive supports for the fabrication of plastic smart windows. To this purpose, tungsten trioxide thin films are deposited by the reactive sputtering technique on the ITO/PC structures, and the resulting single electrode EC devices are characterized by chronoamperometric experiments and cyclic voltammetry. The fast switching response between colored and bleached states, together with the stability and reversibility of their electrochromic behavior after several cycling tests, are considered to be representative of the high quality of the EC film but especially of the ITO electrode. Indeed, even if no adhesion promoters, additional surface activation pretreatments, or substrate heating were used to promote the mechanical adhesion among the electrode and the PC surface, the observed EC response confirmed that the developed materials can be successfully employed for the

  16. Thermal Catalytic Oxidation of Airborne Contaminants by a Reactor Using Ultra-Short Channel Length, Monolithic Catalyst Substrates

    NASA Technical Reports Server (NTRS)

    Perry, J. L.; Tomes, K. M.; Tatara, J. D.

    2005-01-01

    Contaminated air, whether in a crewed spacecraft cabin or terrestrial work and living spaces, is a pervasive problem affecting human health, performance, and well being. The need for highly effective, economical air quality processes spans a wide range of terrestrial and space flight applications. Typically, air quality control processes rely on absorption-based processes. Most industrial packed-bed adsorption processes use activated carbon. Once saturated, the carbon is either dumped or regenerated. In either case, the dumped carbon and concentrated waste streams constitute a hazardous waste that must be handled safely while minimizing environmental impact. Thermal catalytic oxidation processes designed to address waste handling issues are moving to the forefront of cleaner air quality control and process gas decontamination processes. Careful consideration in designing the catalyst substrate and reactor can lead to more complete contaminant destruction and poisoning resistance. Maintenance improvements leading to reduced waste handling and process downtime can also be realized. Performance of a prototype thermal catalytic reaction based on ultra-short waste channel, monolith catalyst substrate design, under a variety of process flow and contaminant loading conditions, is discussed.

  17. Steady-state kinetics with nitric oxide reductase (NOR): new considerations on substrate inhibition profile and catalytic mechanism.

    PubMed

    Duarte, Américo G; Cordas, Cristina M; Moura, José J G; Moura, Isabel

    2014-03-01

    Nitric oxide reductase (NOR) from denitrifying bacteria is an integral membrane protein that catalyses the two electron reduction of NO to N2O, as part of the denitrification process, being responsible for an exclusive reaction, the NN bond formation, the key step of this metabolic pathway. Additionally, this class of enzymes also presents residual oxidoreductase activity, reducing O2 to H2O in a four electron/proton reaction. In this work we report, for the first time, steady-state kinetics with the Pseudomonas nautica NOR, either in the presence of its physiological electron donor (cyt. c552) or immobilised on a graphite electrode surface, in the presence of its known substrates, namely NO or O2. The obtained results show that the enzyme has high affinity for its natural substrate, NO, and different kinetic profiles according to the electron donor used. The kinetic data, as shown by the pH dependence, is modelled by ionisable amino acid residues nearby the di-nuclear catalytic site. The catalytic mechanism is revised and a mononitrosyl-non-heme Fe complex (FeB(II)-NO) species is favoured as the first catalytic intermediate involved on the NO reduction. PMID:24412239

  18. Spectroscopic Ellipsometry Measurements of Wurtzite Gallium Nitride Surfaces as a Function of Buffered Oxide Etch Substrate Submersion

    NASA Astrophysics Data System (ADS)

    Szwejkowski, Chester; Constantin, Costel; Duda, John; Hopkins, Patrick; Optical Studies of GaN interfaces Collaboration

    2013-03-01

    Gallium nitride (GaN) is considered the most important semiconductor after the discovery of silicon. Understanding the optical properties of GaN surfaces is imperative in determining the utility and applicability of this class of materials to devices. In this work, we present preliminary results of spectroscopic ellipsometry measurements as a function of surface root mean square (RMS). We used commercially available 5mm x 5mm, one side polished GaN (3-7 μm)/Sapphire (430 μm) substrates that have a wurtzite crystal structure and they are slightly n-type doped. The GaN substrates were cleaned with Acetone (20 min)/Isopropanol(20 min)/DI water (20 min) before they were submerged into Buffered Oxide Etch (BOE) for 10s - 60s steps. This BOE treatment produced RMS values of 1-30 nm as measured with an atomic force microscope. Preliminary qualitative ellipsometric measurements show that the complex refractive index and the complex dielectric function decrease with an increase of RMS. More measurements need to be done in order to provide explicit quantitative results. This work was supported by the 4-VA Collaborative effort between James Madison University and University of Virginia.

  19. Lateral-coupling coplanar-gate oxide-based thin-film transistors on bare paper substrates

    NASA Astrophysics Data System (ADS)

    Wu, Guodong; Wan, Xiang; Yang, Yi; Jiang, Shuanghe

    2014-11-01

    For conventional thin-film transistors (TFTs), bottom-gate or top-gate configuration is always adopted because the channel current is generally controlled by vertical capacitive coupling. In this article, depending on huge lateral electric-double-layer (EDL) capacitor induced by spatial movement of protons in phosphosilicate glass (PSG) solid electrolyte dielectrics, coplanar-gate indium-zinc-oxide (IZO)-TFTs based on the lateral capacitive coupling were fabricated on bare paper substrates. The PSG solid electrolyte films here were used at the same time as gate dielectrics and smooth buffer layers. These TFTs showed a low-voltage operation of only 1 V with a large field-effect mobility of 13.4 cm2 V-1·s, a high current on/off ratio of 6  ×  106 and a small subthreshold swing of 75 mV/decade. Furthermore, with introducing another coplanar gate, AND logic operation was also demonstrated on the coplanar dual-gate TFTs. These simple lateral-coupling coplanar-gate IZO-TFTs on bare paper substrates are very promising for low-cost portable sensors and bio-electronics.

  20. Effect of methanogenic substrates on anaerobic oxidation of methane and sulfate reduction by an anaerobic methanotrophic enrichment

    PubMed Central

    Jagersma, Christian G.; Khadem, Ahmad F.; Stams, Alfons J. M.; Lens, Piet N. L.

    2010-01-01

    Anaerobic oxidation of methane (AOM) coupled to sulfate reduction (SR) is assumed to be a syntrophic process, in which methanotrophic archaea produce an interspecies electron carrier (IEC), which is subsequently utilized by sulfate-reducing bacteria. In this paper, six methanogenic substrates are tested as candidate-IECs by assessing their effect on AOM and SR by an anaerobic methanotrophic enrichment. The presence of acetate, formate or hydrogen enhanced SR, but did not inhibit AOM, nor did these substrates trigger methanogenesis. Carbon monoxide also enhanced SR but slightly inhibited AOM. Methanol did not enhance SR nor did it inhibit AOM, and methanethiol inhibited both SR and AOM completely. Subsequently, it was calculated at which candidate-IEC concentrations no more Gibbs free energy can be conserved from their production from methane at the applied conditions. These concentrations were at least 1,000 times lower can the final candidate-IEC concentration in the bulk liquid. Therefore, the tested candidate-IECs could not have been produced from methane during the incubations. Hence, acetate, formate, methanol, carbon monoxide, and hydrogen can be excluded as sole IEC in AOM coupled to SR. Methanethiol did inhibit AOM and can therefore not be excluded as IEC by this study. PMID:20445975

  1. Part 2: Ultra-short pulse laser patterning of very thin indium tin oxide on glass substrates

    NASA Astrophysics Data System (ADS)

    McDonnell, C.; Milne, D.; Chan, H.; Rostohar, D.; O'Connor, G. M.

    2016-06-01

    We investigate selective patterning of ultra-thin 20 nm Indium Tin Oxide (ITO) thin films on glass substrates, using 343, 515, and 1030 nm femtosecond (fs), and 1030 nm picoseconds (ps) laser pulses. An ablative removal mechanism is observed for all wavelengths at both femtosecond and picoseconds time-scales. The absorbed threshold fluence values were determined to be 12.5 mJ cm-2 at 343 nm, 9.68 mJ cm-2 at 515 nm, and 7.50 mJ cm-2 at 1030 nm for femtosecond and 9.14 mJ cm-2 at 1030 nm for picosecond laser exposure. Surface analysis of ablated craters using atomic force microscopy confirms that the selective removal of the film from the glass substrate is dependent on the applied fluence. Film removal is shown to be primarily through ultrafast lattice deformation generated by an electron blast force. The laser absorption and heating process was simulated using a two temperature model (TTM). The predicted surface temperatures confirm that film removal below 1 J cm-2 to be predominately by a non-thermal mechanism.

  2. Substrate Controlled Synthesis of Benzisoxazole and Benzisothiazole Derivatives via PhI(OAc)2-Mediated Oxidation Followed by Intramolecular Oxidative O-N/S-N Bond Formation.

    PubMed

    Anand, Devireddy; Patel, Om P S; Maurya, Rahul K; Kant, Ruchir; Yadav, Prem P

    2015-12-18

    A phenyliodine(III) diacetate (PIDA)-mediated, highly efficient and tandem approach for the synthesis of aryldiazenylisoxazolo(isothiazolo)arenes from simple 2-amino-N'-arylbenzohydrazides has been developed. The reaction proceeds via formation of (E)-(2-aminoaryl)(aryldiazenyl)methanone as the key intermediate, followed by intramolecular oxidative O-N/S-N bond formation in one pot at room temperature. The quiet different reactivity of the substrate is due to the formation of a diazo intermediate which encounters a nucleophilic attack by carbonyl oxygen on the electrophilic amine to produce isoxazole products, as compared to the previous reportsa,b,4 in which an N-acylnitrenium ion intermediate is intramolecularly trapped by an amine group. PMID:26565748

  3. Fabrication of tantalum oxide/carbon nanotubes thin film composite on titanium substrate.

    PubMed

    Arnould, C; Korányi, T I; Delhalle, J; Mekhalif, Z

    2010-04-15

    The development of new biomaterials is one of the most challenging tasks in material science. Metals and particularly titanium and its alloys are widely used because of their good corrosion resistance, mechanical properties and biocompatibility. However, the toxicity of alloys, long term degradation in body fluids and risks of loosening are still problematic. To increase the corrosion resistance of the material and reduce ion release, our interest focused on tantalum, another metal well known for its excellent biocompatibility and resistance to bio-corrosion. These very good properties make tantalum a metal of interest for biomaterials but its high cost and high density disqualify it for use as bulk material. In this paper, we propose to combine the good bulk properties of titanium with the excellent surface properties of tantalum by using sol-gel deposition of a tantalum oxide layer on bare titanium. Furthermore, as orthopedics implants are part of our long term goals, we report on the formation of a composite layer of tantalum oxide and multiwalled carbon nanotubes (MWCNTs). MWCNTs have been shown to have promising properties in contact with bone and bone cells and could strengthen the implant. Characterizations are performed using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). PMID:20122696

  4. Instantaneous and continuous measurement of /sup 14/C-labeled substrate oxidation to /sup 14/CO2 by minute tissue specimens: an ionization chamber method

    SciTech Connect

    Davidson, W.D.; Klein, K.L.; Kurokawa, K.; Soll, A.H.

    1981-06-01

    The vibrating reed electrometer and ionization chamber have been adapted for the instantaneous and continuous measurement of /sup 14/C-labeled substrate oxidation to /sup 14/CO2 by minute quantities of isolated tissues. This modified technique, utilizing a ''closed'' circulation incubation system, is 10-50 times as sensitive as the previously described ''open'' circulation techniques. Substrate oxidation curves are described for human erythrocytes and polymorphonuclear leucocytes, canine parietal cells and isolated segments of the rat nephron. This apparatus should prove to be a useful tool for metabolic studies of small quantities of isolated tissue.

  5. Effect of Pore Size and Film Thickness on Gold-Coated Nanoporous Anodic Aluminum Oxide Substrates for Surface-Enhanced Raman Scattering Sensor

    PubMed Central

    Kassu, Aschalew; Farley, Carlton; Sharma, Anup; Kim, Wonkyu; Guo, Junpeng

    2015-01-01

    A sensitive surface enhanced Raman scattering chemical sensor is demonstrated by using inexpensive gold-coated nanoporous anodic aluminum oxide substrates. To optimize the performance of the substrates for sensing by the Surface-enhanced Raman scattering (SERS) technique, the size of the nanopores is varied from 18 nm to 150 nm and the gold film thickness is varied from 30 nm to 120 nm. The sensitivity of gold-coated nanoporous surface enhanced Raman scattering sensor is characterized by detecting low concentrations of Rhodamine 6G laser dye molecules. The morphology of the SERS substrates is characterized by atomic force microscopy. Optical properties of the nanoporous SERS substrates including transmittance, reflectance, and absorbance are also investigated. Relative signal enhancement is plotted for a range of substrate parameters and a detection limit of 10−6 M is established. PMID:26633402

  6. Enzyme-substrate complementarity governs access to a cationic reaction manifold in the P450(BM3)-catalysed oxidation of cyclopropyl fatty acids.

    PubMed

    Cryle, Max J; Hayes, Patricia Y; De Voss, James J

    2012-12-01

    The products of cytochrome P450(BM3)-catalysed oxidation of cyclopropyl-containing dodecanoic acids are consistent with the presence of a cationic reaction intermediate, which results in efficient dehydrogenation of the rearranged probes by the enzyme. These results highlight the importance of enzyme-substrate complementarity, with a cationic intermediate occurring only when the probes used begin to diverge from ideal substrates for this enzyme. This also aids in reconciling literature reports supporting the presence of cationic intermediates with certain cytochrome P450 enzyme/substrate pairs. PMID:23109039

  7. Flexible indium zinc oxide/Ag/indium zinc oxide multilayer electrode grown on polyethersulfone substrate by cost-efficient roll-to-roll sputtering for flexible organic photovoltaics

    SciTech Connect

    Park, Yong-Seok; Kim, Han-Ki

    2010-01-15

    The authors describe the preparation and characteristics of flexible indium zinc oxide (IZO)-Ag-IZO multilayer electrodes grown on flexible polyethersulfone (PES) substrates using a roll-to-roll sputtering system for use in flexible organic photovoltaics. By the continuous roll-to-roll sputtering of the bottom IZO, Ag, and top IZO layers at room temperature, they were able to fabricate a high quality IZO-Ag-IZO multilayer electrode with a sheet resistance of 6.15 {epsilon}/square, optical transmittance of 87.4%, and figure of merit value of 42.03x10{sup -3} {Omega}{sup -1} on the PES substrate. In addition, the IZO-Ag-IZO multilayer electrode exhibited superior flexibility to the roll-to-roll sputter grown single ITO electrode due to the existence of a ductile Ag layer between the IZO layers and stable amorphous structure of the IZO film. Furthermore, the flexible organic solar cells (OSCs) fabricated on the roll-to-roll sputter grown IZO-Ag-IZO electrode showed higher power efficiency (3.51%) than the OSCs fabricated on the roll-to-roll sputter grown single ITO electrode (2.67%).

  8. Nanostructural surface engineering of grafted polymers on inorganic oxide substrates for membrane separations

    NASA Astrophysics Data System (ADS)

    Yoshida, Wayne Hiroshi

    Nanostructural engineering of inorganic substrates by free radical graft polymerization was studied with the goal of developing new membrane materials for pervaporation. Graft polymerization consisted of modification of surface hydroxyls with vinyl trimethoxysilane, followed by solution graft polymerization reaction using either vinyl acetate (VAc) or vinyl pyrrolidone (VP). The topology of the modified surfaces was studied by atomic force microscopy (AFM) on both atomically smooth silicon wafer substrates and microporous inorganic membrane supports in order to deduce the effects of modification on the nanostructural properties of the membrane. While unmodified wafers showed a root-mean-square (RMS) surface roughness of 0.21 +/- 0.03 nm, roughness increased to 3.15 +/- 0.23 nm upon silylation. Under poor solvent conditions (i.e., air), surfaces modified with higher poly(vinyl acetate) (PVAc) or poly(vinyl pyrrolidone) (PVP) polymer graft yields displayed lateral inhomogeneities in the polymer layer. Although RMS surface roughness was nearly identical (0.81--0.85 nm) for PVAc-modified surfaces grafted at different monomer concentrations, the skewness of the height distribution decreased from 2.22 to 0.78 as polymer graft yield increased from 0.8 to 3.5 mg/m2. The polymer-modified surfaces were used to create inorganic pervaporation membranes consisting of a single macromolecular separation layer formed by graft polymerization. PVAc grafted silica membranes (500A native pore size) were found selective for MTBE in the separation of 0.1--1% (v/v) MTBE from water, achieving MTBE enrichment factors as high as 371 at a permeate flux of 0.38 l/m2 hr and a Reynolds number of 6390; however, these membranes could not separate anhydrous organic mixtures. Pervaporative separation of methanol/MTBE mixtures was possible with PVAc and PVP-modified alumina supports of 50A native pore size, where the separation layer consisted of grafted polymer chains with estimated radius of

  9. Validation of screening tools to assess appetite among geriatric patients.

    PubMed

    Hanisah, R; Suzana, S; Lee, F S

    2012-07-01

    Poor appetite is one of the main contributing factors of poor nutritional status among elderly individuals. Recognizing the importance of assessment of appetite, a cross sectional study was conducted to determine the validity of appetite screening tools namely, the Council on Nutrition Appetite questionnaire (CNAQ) and the simplified nutritional appetite questionnaire (SNAQ) against the appetite, hunger and sensory perception questionnaire (AHSPQ), measures of nutritional status and food intake among geriatric patients at the main general hospital in Malaysia. Nutritional status was assessed using the subjective global assessment (SGA) while food intake was measured using the dietary history questionnaire (DHQ). Anthropometric parameters included weight, height, body mass index (BMI), calf circumference (CC) and mid upper arm circumference (MUAC). A total of 145 subjects aged 60 to 86 years (68.3 ± 5.8 years) with 31.7% men and 68.3% women were recruited from outpatients (35 subjects) and inpatients (110 subjects) of Kuala Lumpur Hospital of Malaysia. As assessed by SGA, most subjects were classified as mild to moderately malnourished (50.4%), followed by normal (38.6%) and severely malnourished (11.0%). A total of 79.3% and 57.2% subjects were classified as having poor appetite according to CNAQ and SNAQ, respectively. CNAQ (80.9%) had a higher sensitivity than SNAQ (69.7%) when validated against nutritional status as assessed using SGA. However, the specificity of SNAQ (62.5%) was higher than CNAQ (23.2%). Positive predictive value for CNAQ and SNAQ were 62.6% and 74.7%, respectively. Cronbach's alpha for CNAQ and SNAQ were 0.546 and 0.578, respectively. History of weight loss over the past one year (Adjusted odds ratio 2.49) (p < 0.01) and thiamine intake less than the recommended nutrient intake (RNI) (Adjusted odds ratio 3.04) (p < 0.05) were risk factors for poor appetite among subjects. In conclusion, malnutrition and poor appetite were prevalent among the

  10. Substrate-tuning of correlated spin-orbit oxides revealed by optical conductivity calculations

    NASA Astrophysics Data System (ADS)

    Kim, Bongjae; Kim, Beom Hyun; Kim, Kyoo; Min, B. I.

    2016-06-01

    We have systematically investigated substrate-strain effects on the electronic structures of two representative Sr-iridates, a correlated-insulator Sr2IrO4 and a metal SrIrO3. Optical conductivities obtained by the ab initio electronic structure calculations reveal that the tensile strain shifts the optical peak positions to higher energy side with altered intensities, suggesting the enhancement of the electronic correlation and spin-orbit coupling (SOC) strength in Sr-iridates. The response of the electronic structure upon tensile strain is found to be highly correlated with the direction of magnetic moment, the octahedral connectivity, and the SOC strength, which cooperatively determine the robustness of Jeff = 1/2 ground states. Optical responses are analyzed also with microscopic model calculation and compared with corresponding experiments. In the case of SrIrO3, the evolution of the electronic structure near the Fermi level shows high tunability of hole bands, as suggested by previous experiments.

  11. Substrate-tuning of correlated spin-orbit oxides revealed by optical conductivity calculations.

    PubMed

    Kim, Bongjae; Kim, Beom Hyun; Kim, Kyoo; Min, B I

    2016-01-01

    We have systematically investigated substrate-strain effects on the electronic structures of two representative Sr-iridates, a correlated-insulator Sr2IrO4 and a metal SrIrO3. Optical conductivities obtained by the ab initio electronic structure calculations reveal that the tensile strain shifts the optical peak positions to higher energy side with altered intensities, suggesting the enhancement of the electronic correlation and spin-orbit coupling (SOC) strength in Sr-iridates. The response of the electronic structure upon tensile strain is found to be highly correlated with the direction of magnetic moment, the octahedral connectivity, and the SOC strength, which cooperatively determine the robustness of Jeff = 1/2 ground states. Optical responses are analyzed also with microscopic model calculation and compared with corresponding experiments. In the case of SrIrO3, the evolution of the electronic structure near the Fermi level shows high tunability of hole bands, as suggested by previous experiments. PMID:27256281

  12. Reaction mechanisms for atomic layer deposition of aluminum oxide on semiconductor substrates

    SciTech Connect

    Delabie, Annelies; Sioncke, Sonja; Rip, Jens; Van Elshocht, Sven; Pourtois, Geoffrey; Mueller, Matthias; Beckhoff, Burkhard; Pierloot, Kristine

    2012-01-15

    In this work, we have studied the TMA/H{sub 2}O (TMA = Al(CH{sub 3}){sub 3}) atomic layer deposition (ALD) of Al{sub 2}O{sub 3} on hydroxyl (OH) and thiol (SH) terminated semiconductor substrates. Total reflection x-ray fluorescence reveals a complex growth-per-cycle evolution during the early ALD reaction cycles. OH and SH terminated surfaces demonstrate growth inhibition from the second reaction cycle on. Theoretical calculations, based on density functional theory, are performed on cluster models to investigate the first TMA/H{sub 2}O reaction cycle. Based on the theoretical results, we discuss possible mechanisms for the growth inhibition from the second reaction cycle on. In addition, our calculations show that AlCH{sub 3} groups are hydrolyzed by a H{sub 2}O molecule adsorbed on a neighboring Al atom, independent of the type of backbonds (Si-O, Ge-O, or Ge-S) of AlCH{sub 3}. The coordination of Al remains four-fold after the first TMA/H{sub 2}O reaction cycle.

  13. Involvement of singlet oxygen in cytochrome P450-dependent substrate oxidations.

    PubMed

    Osada, M; Ogura, Y; Yasui, H; Sakurai, H

    1999-09-24

    Cytochrome P450 (P450)-dependent p-hydroxylation of aniline and o-deethylation of 7-ethoxycoumarin were examined in rat liver microsomes in the presence of radical scavengers. The addition of beta-carotene, a quencher of singlet oxygen species ((1)O(2)), suppressed the aniline hydroxylation, while the addition of sodium azide (NaN(3)) ((1)O(2) quencher) enhanced the reaction. No other reactive oxygen scavengers or chelating agents such as superoxide dismutase, catalase, dimethylsulfoxide, or deferoxamine altered the reaction. In contrast, the microsomal o-deethylation of 7-ethoxycoumarin was suppressed by the addition of NaN(3). (1)O(2) was detectable during the reaction of microsomes and NADPH by ESR spin-trapping when 2,2,6,6-tetramethyl-4-piperidone (TMPD) was used as a spin trap, and the (1)O(2) was quenched by the additions of beta-carotene, NaN(3), aniline, and 7-ethoxycoumarin. The enhancement effect of NaN(3) in the hydroxylation of aniline appeared to be due to the conformational change of P450 protein, which in turn enhances the binding of aniline to P450 in terms of the spectral dissociation constant (K(s)). In contrast, (1)O(2) appeared to be active in the o-deethylation of 7-ethoxycoumarin. On the basis of the results, the involvement of (1)O(2) in P450-dependent substrate oxygenations is proposed. PMID:10491304

  14. Substrate-tuning of correlated spin-orbit oxides revealed by optical conductivity calculations

    PubMed Central

    Kim, Bongjae; Kim, Beom Hyun; Kim, Kyoo; Min, B. I.

    2016-01-01

    We have systematically investigated substrate-strain effects on the electronic structures of two representative Sr-iridates, a correlated-insulator Sr2IrO4 and a metal SrIrO3. Optical conductivities obtained by the ab initio electronic structure calculations reveal that the tensile strain shifts the optical peak positions to higher energy side with altered intensities, suggesting the enhancement of the electronic correlation and spin-orbit coupling (SOC) strength in Sr-iridates. The response of the electronic structure upon tensile strain is found to be highly correlated with the direction of magnetic moment, the octahedral connectivity, and the SOC strength, which cooperatively determine the robustness of Jeff = 1/2 ground states. Optical responses are analyzed also with microscopic model calculation and compared with corresponding experiments. In the case of SrIrO3, the evolution of the electronic structure near the Fermi level shows high tunability of hole bands, as suggested by previous experiments. PMID:27256281

  15. Photoluminescence Spectroscopy Of Thin Indium-Tin-Oxide Contacts On Mercuric Iodide Substrates

    NASA Astrophysics Data System (ADS)

    James, Ralph B.; Bao, Xue J.; Schlesinger, Tuviah E.; Markakis, Jeff; Cheng, A. Y.; Ortale, Carol

    1989-05-01

    Mercuric iodide (HgI2) photodetectors with sputtered indium-tin-oxide (ITO) entrance electodes were studied using low-temperature photoluminesence spectroscopy. The photoluminescence spectra obtained on each photodetector was found to differ for points beneath the ITO contact and points adjacent to it, indicating that the contact fabrication process introduces new carrier traps and radiative recombination centers within the ITO-HgI2 interfacial region. In particular, a new broad band was observed in the spectra taken from points beneath the ITO electrode. Photo-current-versus-position measurements showed that the intensity of this broad band was enhanced in regions having relatively poor photoresponse. Specimens of HgI2 with evaporated semi-transparent tin and indium films were also investigated. The spectra obtained from points beneath the Sn and In films suggest that the regions having poor photoresponse in the ITO-contacted photodetector contain either free tin or indium metal.

  16. N-sulfotestosteronan, a novel substrate for heparan sulfate 6-O-sulfotransferases and its analysis by oxidative degradation

    PubMed Central

    Li, Guoyun; Masuko, Sayaka; Green, Dixy E.; Xu, Yongmei; Li, Lingyun; Zhang, Fuming; Xue, Changhu; Liu, Jian; DeAngelis, Paul. L.; Linhardt, Robert J.

    2013-01-01

    Testosteronan, an unusual glycosaminoglycan first isolated from the microbe Comamonas testosteroni, was enzymatically synthesized in vitro by transferring uridine diphosphate sugars on β-p-nitrophenyl glucuronide acceptor. After chemically converting testosteronan to N-sulfotestosteronan it was tested as a substrate for sulfotransferases involved in the biosynthesis of the glycosaminoglycan, heparan sulfate. Studies using 35S-labeled 3′-phosphodenosine-5′-phosphosulfate (PAPS) showed that only 6-O-sulfotransferases acted on N-sulfotestosteronan. An oxidative depolymerization reaction was explored to generate oligosaccharides from 34S-labeled 6-O-sulfo-N-sulfotestosteroran using 34S-labeled PAPS because testosteronan was resistant to all of the tested glycosaminoglycan-degrading enzymes. Liquid chromotography-mass spectrometric analysis of the oxidatively depolymerized polysaccharides confirmed the incorporation of 34S into ~14% of the glucosamine residues. Nuclear magnetic resonance spectroscopy also showed that the sulfo groups were transferred to ~20% of the 6-hydroxyl groups in the glucosamine residue of N-sulfotestosteronan. The bioactivity of 6-O–sulfo-N-sulfotestosteronan was examined by performing protein-binding studies with fibroblast growth factors and antithrombin III using a surface plasmon resonance competition assay. The introduction of 6-O-sulfo groups enhanced N-sulfotestosteronan binding to the fibroblast growth factors, but not to antithrombin III. PMID:23606289

  17. CaMKII is a RIP3 substrate mediating ischemia- and oxidative stress-induced myocardial necroptosis.

    PubMed

    Zhang, Ting; Zhang, Yan; Cui, Mingyao; Jin, Li; Wang, Yimei; Lv, Fengxiang; Liu, Yuli; Zheng, Wen; Shang, Haibao; Zhang, Jun; Zhang, Mao; Wu, Hongkun; Guo, Jiaojiao; Zhang, Xiuqin; Hu, Xinli; Cao, Chun-Mei; Xiao, Rui-Ping

    2016-02-01

    Regulated necrosis (necroptosis) and apoptosis are crucially involved in severe cardiac pathological conditions, including myocardial infarction, ischemia-reperfusion injury and heart failure. Whereas apoptotic signaling is well defined, the mechanisms that underlie cardiomyocyte necroptosis remain elusive. Here we show that receptor-interacting protein 3 (RIP3) triggers myocardial necroptosis, in addition to apoptosis and inflammation, through activation of Ca(2+)-calmodulin-dependent protein kinase (CaMKII) rather than through the well-established RIP3 partners RIP1 and MLKL. In mice, RIP3 deficiency or CaMKII inhibition ameliorates myocardial necroptosis and heart failure induced by ischemia-reperfusion or by doxorubicin treatment. RIP3-induced activation of CaMKII, via phosphorylation or oxidation or both, triggers opening of the mitochondrial permeability transition pore and myocardial necroptosis. These findings identify CaMKII as a new RIP3 substrate and delineate a RIP3-CaMKII-mPTP myocardial necroptosis pathway, a promising target for the treatment of ischemia- and oxidative stress-induced myocardial damage and heart failure. PMID:26726877

  18. Stability improvement of organic light emitting diodes by the insertion of hole injection materials on the indium tin oxide substrate

    SciTech Connect

    Chang, Jung-Hung; Liu, Shang-Yi; Wu, I-Wen; Chen, Tsung-Chin; Liu, Chia-Wei; Wu, Chih-I

    2014-03-28

    The degradation of organic light-emitting diodes (OLEDs) is a very complex issue, which might include interfacial charge accumulation, material diffusion, and electrical-induced chemical reaction during the operation. In this study, the origins of improvement in device stability from inserting a hole injection layer (HIL) at the indium tin oxide (ITO) anode are investigated. The results from aging single-layer devices show that leakage current increases in the case of ITO/hole transport layer contact, but this phenomenon can be prevented by inserting molybdenum oxide (MoO{sub 3}) or 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HAT-CN{sub 6}) as an HIL. Moreover, X-ray photoemission spectroscopy suggests that the diffusion of indium atoms and active oxygen species can be impeded by introducing MoO{sub 3} or HAT-CN{sub 6} as an HIL. These results reveal that the degradation of OLEDs is related to indium and oxygen out-diffusion from the ITO substrates, and that the stability of OLEDs can be improved by impeding this diffusion with HILs.

  19. Influence of oxidation on the wetting behavior of liquid silicon on Si 3N 4-coated substrates

    NASA Astrophysics Data System (ADS)

    Brynjulfsen, Ingvild; Bakken, Astrid; Tangstad, Merete; Arnberg, Lars

    2010-08-01

    Silicon nitride coating on a silica substrate has been fired in atmospheres of air, argon and nitrogen, at temperatures of 900 and 1100 °C, with holding times of 30 min, two and four hours. The oxygen concentration after oxidation, measured by LECO analyses, increased with increase in oxidation temperature, time and partial pressure of oxygen. The increase in mass of the coating together with the increase in oxygen concentration corresponded to the formation of a Si 2N 2O layer. Sessile drop wetting experiments with holding temperatures of approximately 50, 100 and 150 °C above the melting point of silicon has been performed. It was found that a high oxygen content in the coating led to enhanced non-wettability properties. Wetting angles around 100° were achieved with oxygen concentrations higher than 14 wt%. In contrast, oxygen levels around 2 wt% resulted in angles around 60°. During the experiments, deoxidation and infiltration of the coating occurred. At high temperatures the reaction rate increased significantly leading to penetration of the coating.

  20. [Prevention and management of appetite loss during cancer chemotherapy].

    PubMed

    Tsujimura, Hideki; Yamada, Mitsugi; Asako, Eri; Kodama, Yukako; Sato, Tsuneo; Nabeya, Yoshihiro

    2014-10-01

    Appetite loss during cancer chemotherapy may lead to malnutrition and a decreased quality of life. To overcome this problem, evidence-based guidelines have been established for chemotherapy-induced emesis and mucositis. However, unsolved issues such as taste alimentation remain. Since the clinical picture of appetite loss is complex, individual management strategies depending on the type of the disease and treatment are required. PMID:25335699

  1. Zinc oxide epitaxial thin film deposited over carbon on various substrate by pulsed laser deposition technique.

    PubMed

    Manikandan, E; Moodley, M K; Sinha Ray, S; Panigrahi, B K; Krishnan, R; Padhy, N; Nair, K G M; Tyagi, A K

    2010-09-01

    Zinc Oxide (ZnO) is a promising candidate material for optical and electronic devices due to its direct wide band gap (3.37 eV) and high exciton binding energy (60 meV). For applications in various fields such as light emitting diode (LED) and laser diodes, growth of p-type ZnO is a prerequisite. ZnO is an intrinsically n-type semiconductor. In this paper we report on the synthesis of Zinc Oxide-Carbon (ZnO:C) thin films using pulsed laser deposition technique (PLD). The deposition parameters were optimized to obtain high quality epitaxial ZnO films over a carbon layer. The structural and optical properties were studied by glazing index X-ray diffraction (GIXRD), photoluminescence (PL), optical absorption (OA), and Raman spectroscopy. Rutherford backscattering spectroscopy (RBS), scanning electron microscopy with energy dispersive spectroscopy (SEMEDS) and atomic force microscopy (AFM) were employed to determine the composition and surface morphology of these thin films. The GIXRD pattern of the synthesized films exhibited hexagonal wurtzite crystal structure with a preferred (002) orientation. PL spectroscopy results showed that the emission intensity was maximum at -380 nm at a deposition temperature of 573 K. In the Raman spectra, the E2 phonon frequency around at 438 cm(-1) is a characteristic peak of the wurtzite lattice and could be seen in all samples. Furthermore, the optical direct band gap of ZnO films was found to be in the visible region. The growth of the epitaxial layer is discussed in the light of carbon atoms from the buffer layer. Our work demonstrates that the carbon is a novel dopant in the group of doped ZnO semiconductor materials. The introduction of carbon impurities enhanced the visible emission of red-green luminescence. It is concluded that the carbon impurities promote the zinc related native defect in ZnO. PMID:21133080

  2. Effects of substrate microstructure on the formation of oriented oxide nanotube arrays on Ti and Ti alloys

    NASA Astrophysics Data System (ADS)

    Ferreira, C. P.; Gonçalves, M. C.; Caram, R.; Bertazzoli, R.; Rodrigues, C. A.

    2013-11-01

    The formation of nanotubular oxide layers on Ti and Ti alloys has been widely investigated for the photocatalytic degradation of organic compounds due to their excellent catalytic efficiency, chemical stability, and low cost and toxicity. Aiming to improve the photocatalytic efficiency of this nanostructured oxide, this work investigated the influence of substrate grain size on the growth of nanotubular oxide layers. Ti and Ti alloys (Ti-6Al, Ti-6Al-7Nb) were produced by arc melting with non-consumable tungsten electrode and water-cooled copper hearth under argon atmosphere. Some of the ingots were heat-treated at 1000 °C for 12 and 24 h in argon atmosphere, followed by slow cooling rates to reduce crystalline defects and increase the grain size of their microstructures. Three types of samples were anodized: commercial substrate, as-prepared and heat-treated samples. The anodization was performed using fluoride solution and a cell potential of 20 V. The samples were characterized by optical microscopy, field-emission scanning electron microscopy and X-ray diffraction. The heat treatment preceding the anodization process increased the grain size of pure Ti and Ti alloys and promoted the formation of Widmanstätten structures in Ti6Al7Nb. The nanotubes layers grown on smaller grain and thermally untreated samples were more regular and homogeneous. In the case of Ti-6Al-7Nb alloy, which presents a α + β phase microstructure, the morphology of nanotubes nucleated on α matrix was more regular than those of nanotubes nucleated on β phase. After the annealing process, the Ti-6Al-7Nb alloy presented full diffusion process and the growth of equilibrium phases resulting in the appearance of regions containing higher concentrations of Nb, i.e. beta phase. In those regions the dissolution rate of Nb2O5 is lower than that of TiO2, resulting in a nanoporous layer. In general, heat treating reduces crystalline defects and promotes the increasing of the grain sizes, not

  3. Appetitive conditioning: neural bases and implications for psychopathology

    PubMed Central

    Martin-Soelch, C; Linthicum, J.; Ernst, M

    2009-01-01

    Appetitive conditioning is the process through which new rewards are learned and acquire their motivational salience. Although it has the same evolutionary survival significance as aversive conditioning, appetitive conditioning has rarely been studied in humans. This gap may be explained by the difficulty to find in humans suitable appetitive stimuli that can elicit physiological responses similar to those elicited by aversive stimuli. To help remedy this gap, we review the literature on conditioning, with emphasis on appetitive conditioning. This review comprises three parts. First, we examine the different forms of conditioning. Second, we review the neural basis of appetitive conditioning, particularly from a functional neuroimaging perspective. And third, we demonstrate how perturbations in processes involved in appetitive conditioning can be involved in psychopathologies and suggest neurobiological models underlying these pathologies. The ultimate goal of this review is to stimulate new avenues of research that have direct links to molecular biology, and thus could prove to be invaluable to progress in the understanding and treatment of psychiatric disabilities. PMID:17210179

  4. Appetitive conditioning: neural bases and implications for psychopathology.

    PubMed

    Martin-Soelch, C; Linthicum, J; Ernst, M

    2007-01-01

    Appetitive conditioning is the process through which new rewards are learned and acquire their motivational salience. Although it has the same evolutionary survival significance as aversive conditioning, appetitive conditioning has rarely been studied in humans. This gap may be explained by the difficulty to find in humans suitable appetitive stimuli that can elicit physiological responses similar to those elicited by aversive stimuli. To help remedy this gap, we review the literature on conditioning, with emphasis on appetitive conditioning. This review comprises three parts. First, we examine the different forms of conditioning. Second, we review the neural basis of appetitive conditioning, particularly from a functional neuroimaging perspective. And third, we demonstrate how perturbations in processes involved in appetitive conditioning can contribute to implicated psychopathologies and suggest neurobiological models underlying these pathologies. The ultimate goal of this review is to stimulate new avenues of research that have direct links to molecular biology, and thus could prove to be invaluable to progress in the understanding and treatment of psychiatric disabilities. PMID:17210179

  5. Increased oxidative stress and apoptosis in the hypothalamus of diabetic male mice in the insulin receptor substrate-2 knockout model.

    PubMed

    Baquedano, Eva; Burgos-Ramos, Emma; Canelles, Sandra; González-Rodríguez, Agueda; Chowen, Julie A; Argente, Jesús; Barrios, Vicente; Valverde, Angela M; Frago, Laura M

    2016-05-01

    Insulin receptor substrate-2-deficient (IRS2(-/-)) mice are considered a good model to study the development of diabetes because IRS proteins mediate the pleiotropic effects of insulin-like growth factor-I (IGF-I) and insulin on metabolism, mitogenesis and cell survival. The hypothalamus might play a key role in the early onset of diabetes, owing to its involvement in the control of glucose homeostasis and energy balance. Because some inflammatory markers are elevated in the hypothalamus of diabetic IRS2(-/-) mice, our aim was to analyze whether the diabetes associated with the absence of IRS2 results in hypothalamic injury and to analyze the intracellular mechanisms involved. Only diabetic IRS2(-/-) mice showed increased cell death and activation of caspase-8 and -3 in the hypothalamus. Regulators of apoptosis such as FADD, Bcl-2, Bcl-xL and p53 were also increased, whereas p-IκB and c-FLIPL were decreased. This was accompanied by increased levels of Nox-4 and catalase, enzymes involved in oxidative stress. In summary, the hypothalamus of diabetic IRS2(-/-) mice showed an increase in oxidative stress and inflammatory markers that finally resulted in cell death via substantial activation of the extrinsic apoptotic pathway. Conversely, non-diabetic IRS2(-/-) mice did not show cell death in the hypothalamus, possibly owing to an increase in the levels of circulating IGF-I and in the enhanced hypothalamic IGF-IR phosphorylation that would lead to the stimulation of survival pathways. In conclusion, diabetes in IRS2-deficient male mice is associated with increased oxidative stress and apoptosis in the hypothalamus. PMID:27013528

  6. Increased oxidative stress and apoptosis in the hypothalamus of diabetic male mice in the insulin receptor substrate-2 knockout model

    PubMed Central

    Canelles, Sandra; Argente, Jesús; Barrios, Vicente

    2016-01-01

    ABSTRACT Insulin receptor substrate-2-deficient (IRS2−/−) mice are considered a good model to study the development of diabetes because IRS proteins mediate the pleiotropic effects of insulin-like growth factor-I (IGF-I) and insulin on metabolism, mitogenesis and cell survival. The hypothalamus might play a key role in the early onset of diabetes, owing to its involvement in the control of glucose homeostasis and energy balance. Because some inflammatory markers are elevated in the hypothalamus of diabetic IRS2−/− mice, our aim was to analyze whether the diabetes associated with the absence of IRS2 results in hypothalamic injury and to analyze the intracellular mechanisms involved. Only diabetic IRS2−/− mice showed increased cell death and activation of caspase-8 and -3 in the hypothalamus. Regulators of apoptosis such as FADD, Bcl-2, Bcl-xL and p53 were also increased, whereas p-IκB and c-FLIPL were decreased. This was accompanied by increased levels of Nox-4 and catalase, enzymes involved in oxidative stress. In summary, the hypothalamus of diabetic IRS2−/− mice showed an increase in oxidative stress and inflammatory markers that finally resulted in cell death via substantial activation of the extrinsic apoptotic pathway. Conversely, non-diabetic IRS2−/− mice did not show cell death in the hypothalamus, possibly owing to an increase in the levels of circulating IGF-I and in the enhanced hypothalamic IGF-IR phosphorylation that would lead to the stimulation of survival pathways. In conclusion, diabetes in IRS2-deficient male mice is associated with increased oxidative stress and apoptosis in the hypothalamus. PMID:27013528

  7. Introduction of thiol moieties, including their thiol-ene reactions and air oxidation, onto polyelectrolyte multilayer substrates.

    PubMed

    Madaan, Nitesh; Romriell, Naomi; Tuscano, Joshua; Schlaad, Helmut; Linford, Matthew R

    2015-12-01

    We describe the derivatization of uncross-linked and cross-linked layer-by-layer (LbL) assemblies of polyelectrolytes (polyallylamine hydrochloride and polyacrylic acid) with sulfydryl groups via Traut's reagent (2-iminothiolane). This thiolation was optimized with regards to temperature, concentration, and pH. The stability of the resulting -SH groups in the air was determined by X-ray photoelectron spectroscopy (XPS). This air oxidation has obvious implications for the use of thiol-ene reactions in materials chemistry, and there appears to be little on this topic in the literature. Three main S 2s signals were observed by XPS: at 231.5 eV (oxidized sulfur), 227.6 eV (thiol groups), and 225.4 eV (thiolate groups). Due to their rapid oxidation, we recommend that thiolated surfaces be used immediately after they are prepared. As driven by 254 nm UV light, thiol groups on polyelectrolyte multilayers react with 1,2-polybutadiene (PBd), and residual carbon-carbon double bonds on adsorbed PBd similarly react with another thiol. In the case of a fluorinated thiol, surfaces with high water contact angles (ca. 120°) are obtained. Modest exposures to light result in derivatization, while longer exposures damage the assemblies. Polyelectrolyte-thiol-PBd-thiol assemblies delaminate from their substrates when immersed for long periods of time in water. Surface silanization with an amino silane prevents this delamination and leads to stable assemblies. These assemblies withstand various stability tests. Techniques used to analyze the materials in this study include X-ray photoelectron spectroscopy (XPS), spectroscopic ellipsometry (SE), atomic force microscopy (AFM), and contact angle goniometry. PMID:26295196

  8. Probing the chemical steps of nitroalkane oxidation catalyzed by 2-nitropropane dioxygenase with solvent viscosity, pH, and substrate kinetic isotope effects.

    PubMed

    Francis, Kevin; Gadda, Giovanni

    2006-11-21

    Among the enzymes that catalyze the oxidative denitrification of nitroalkanes to carbonyl compounds, 2-nitropropane dioxygenase is the only one known to effectively utilize both the neutral and anionic (nitronate) forms of the substrate. A recent study has established that the catalytic pathway is common to both types of substrates, except for the initial removal of a proton from the carbon of the neutral substrates [Francis, K., Russell, B., and Gadda, G. (2005) J. Biol. Chem. 280, 5195-5204]. In the present study, the mechanistic properties of the enzyme have been investigated with solvent viscosity, pH, and kinetic isotope effects. With nitroethane or ethylnitronate, the kcat/Km and kcat values were independent of solvent viscosity, consistent with the substrate and product binding to the enzyme in rapid equilibrium. The abstraction of the proton from the alpha carbon of neutral substrates was investigated by measuring the pH dependence of the D(kcat/KNE) value with 1,1-[2H2]-nitroethane. The formation of the enzyme-bound flavosemiquinone formed during catalysis was examined by determining the pH dependence of the kcat/Km values with ethylnitronate and nitroethane and the inhibition by m-nitrobenzoate. Finally, alpha-secondary kinetic isotope effects with 1-[2H]-ethylnitronate were used to propose a non-oxidative tautomerization pathway, in which the enzyme catalyzes the interconversion of nitroalkanes between their anionic and neutral forms. The data presented suggest that enzymatic turnover of 2-nitropropane dioxygenase with neutral substrates is limited by the cleavage of the substrate CH bond at low pH, whereas that with anionic substrates is limited by the non-oxidative tautomerization of ethylnitroante to nitroethane at high pH. PMID:17105207

  9. Critical nitric oxide concentration for Pseudomonas aeruginosa biofilm reduction on polyurethane substrates.

    PubMed

    Neufeld, Bella H; Reynolds, Melissa M

    2016-01-01

    Bacterial colonies that reside on a surface, known as biofilms, are intrinsically impenetrable to traditional antibiotics, ultimately driving research toward an alternative therapeutic approach. Nitric oxide (NO) has gained attention for its biologically beneficial properties, particularly centered around its antibacterial capabilities. NO donors that can release the molecule under physiological conditions (such as S-nitrosothiols) can be utilized in clinical settings to combat bacterial biofilm infections. Herein the authors describe determining a critical concentration of NO necessary to cause >90% reduction of a Pseudomonas aeruginosa biofilm grown on medical grade polyurethane films. The biofilm was grown under optimal culture conditions [in nutrient broth media (NBM) at 37 °C] for 24 h before the addition of the NO donor S-nitrosoglutathione (GSNO) in NBM for an additional 24 h. The cellular viability of the biofilm after the challenge period was tested using varying concentrations of NO to determine the critical amount necessary to cause at least a 90% reduction in bacterial biofilm viability. The critical GSNO concentration was found to be 10 mM, which corresponds to 2.73 mM NO. Time kill experiments were performed on the 24 h biofilm using the critical amount of NO at 4, 8, 12, and 16 h and it was determined that the 90% biofilm viability reduction occurred at 12 h and was sustained for the entire 24 h challenge period. This critical concentration was subsequently tested for total NO release via a nitric oxide analyzer. The total amount of NO released over the 12 h challenge period was found to be 5.97 ± 0.66 × 10(-6) mol NO, which corresponds to 1.49 ± 0.17 μmol NO/ml NBM. This is the first identification of the critical NO concentration needed to elicit this biological response on a medically relevant polymer. PMID:27604080

  10. Preferential Growth of Semiconducting Single-Walled Carbon Nanotubes on Substrate by Europium Oxide

    PubMed Central

    2010-01-01

    In this paper, we have demonstrated that europium oxide (Eu2O3) is a new type of active catalyst for single-walled carbon nanotubes (SWNTs) growth under suitable conditions. Both random SWNT networks and horizontally aligned SWNT arrays are efficiently grown on silicon wafers. The density of the SWNT arrays can be altered by the CVD conditions. This result further provides the experimental evidence that the efficient catalyst for SWNT growth is more size dependent than the catalysts themselves. Furthermore, the SWNTs from europium sesquioxides have compatibly higher quality than that from Fe/Mo catalyst. More importantly, over 80% of the nanotubes from Eu2O3 are semiconducting SWNTs (s-SWNTs), indicating the preferential growth of s-SWNTs from Eu2O3. This new finding could open a way for selective growth of s-SWNTs, which can be used as high-current nanoFETs and sensors. Moreover, the successful growth of SWNTs by Eu2O3 catalyst provides new experimental information for understanding the preferential growth of s-SWNTs from Eu2O3, which may be helpful for their controllable synthesis. PMID:21076709

  11. Substrate dependant capacitive performance of spray pyrolysed titanium oxide (TiO2) thin films

    NASA Astrophysics Data System (ADS)

    Fugare, B. Y.; Ingole, R. S.; Ambare, R. C.; Lokhande, B. J.

    2016-04-01

    Using 60 ml, 0.06 M aqueous solution of potassium titanium oxalate (pto), thin films of titanium oxide were prepared by using well known spray pyrolysis technique. Depositions of the films carried out at 723° K by maintain the spray rate 12 Cc/min. prepared thin films were characterized structurally, morphologically and electrochemically. Sample shows tetragonal crystal structure with rutile as prominent phase at very low deposition temperature. SEM morphology shows porous, dense, nanorods and nanoplates like morphology. The electrochemical cyclic voltammetery shows mixed capacitive behavior. The specific capacitance values observed from cyclic voltammetery in 1 M NaOH are 2497.19, 29.60, 424.22 F/g. for the electrode deposited on copper, FTO and stainless steel (SS) respectively. Charge discharge behavior was observed for the samples deposited on stainless steel gives specific energy (SE), specific power (SP) and efficiency (η) are 43.25 Wh/kg, 35.25 kW/kg and 98.22 % respectively. Impedance study was carried out in the frequency range 1 mHz to 1 MHz exhibits very less internal resistance 1.066 Ohm for the deposited electrode.

  12. Initiation of atomic layer deposition of metal oxides on polymer substrates by water plasma pretreatment

    SciTech Connect

    Steven Brandt, E.; Grace, Jeremy M.

    2012-01-15

    The role of surface hydroxyl content in atomic layer deposition (ALD) of aluminum oxide (AO) on polymers is demonstrated by performing an atomic layer deposition of AO onto a variety of polymer types, before and after pretreatment in a plasma struck in water vapor. The treatment and deposition reactions are performed in situ in a high vacuum chamber that is interfaced to an x-ray photoelectron spectrometer to prevent adventitious exposure to atmospheric contaminants. X-ray photoelectron spectroscopy is used to follow the surface chemistries of the polymers, including theformation of surface hydroxyls and subsequent growth of AO by ALD. Using dimethyl aluminum isopropoxide and water as reactants, ALD is obtained for water-plasma-treated poly(styrene) (PS), poly(propylene) (PP), poly(vinyl alcohol) (PVA), and poly(ethylene naphthalate) (PEN). For PS, PP, and PEN, initial growth rates of AO on the native (untreated) polymers are at least an order of magnitude lower than on the same polymer surface following the plasma treatment. By contrast, native PVA is shown to initiate ALD of AO as a result of the presence of intrinsic surface hydroxyls that are derived from the repeat unit of this polymer.

  13. Substrate arrays of iridium oxide microelectrodes for in vitro neuronal interfacing.

    PubMed

    Gawad, Shady; Giugliano, Michele; Heuschkel, Marc; Wessling, Börge; Markram, Henry; Schnakenberg, Uwe; Renaud, Philippe; Morgan, Hywel

    2009-01-01

    The design of novel bidirectional interfaces for in vivo and in vitro nervous systems is an important step towards future functional neuroprosthetics. Small electrodes, structures and devices are necessary to achieve high-resolution and target-selectivity during stimulation and recording of neuronal networks, while significant charge transfer and large signal-to-noise ratio are required for accurate time resolution. In addition, the physical properties of the interface should remain stable across time, especially when chronic in vivo applications or in vitro long-term studies are considered, unless a procedure to actively compensate for degradation is provided. In this short report, we describe the use and fabrication of arrays of 120 planar microelectrodes (MEAs) of sputtered Iridium Oxide (IrOx). The effective surface area of individual microelectrodes is significantly increased using electrochemical activation, a procedure that may also be employed to restore the properties of the electrodes as required. The electrode activation results in a very low interface impedance, especially in the lower frequency domain, which was characterized by impedance spectroscopy. The increase in the roughness of the microelectrodes surface was imaged using digital holographic microscopy and electron microscopy. Aging of the activated electrodes was also investigated, comparing storage in saline with storage in air. Demonstration of concept was achieved by recording multiple single-unit spike activity in acute brain slice preparations of rat neocortex. Data suggests that extracellular recording of action potentials can be achieved with planar IrOx MEAs with good signal-to-noise ratios. PMID:19194527

  14. Appetite sensations, appetite signaling proteins, and glucose in obese adolescents with subclinical binge eating disorder.

    PubMed

    Adamo, Kristi B; Wilson, Shanna L; Ferraro, Zachary M; Hadjiyannakis, Stasia; Doucet, Eric; Goldfield, Gary S

    2014-01-01

    Objective. This study aimed to investigate potential differences in appetite sensations, ghrelin, peptide YY, and glucose and their relationship with energy and macronutrient intake in obese adolescents with subclinical binge eating disorder. Methods. Fifteen obese adolescents (six and nine individuals with and without subclinical binge eating disorder, resp.) qualified for this study. Visual analog scales and Three-Factor Eating Questionnaires were used to assess eating behaviours. Circulating ghrelin, peptide YY, and glucose were measured after fasting and at multiple time points postprandially following a standardized breakfast meal. Energy and macronutrient intake were measured with an ad libitum lunch buffet. Results. Emotional eating scores were significantly higher in obese adolescents with subclinical binge eating disorder. Hunger levels rose and satiety levels fell significantly over the course of the monitoring period but there was no difference between the two groups. Obese adolescents with subclinical binge eating disorder did not have significantly different levels of appetite signaling proteins or glucose. Obese adolescents with subclinical binge eating disorder had a nonsignificantly higher energy and macronutrient intake. Conclusions. A significant difference between the two groups in terms of their emotional eating scores highlights the important role that psychological factors play in relation to eating behaviours. PMID:25006530

  15. Structural and optical properties of Ag-doped copper oxide thin films on polyethylene napthalate substrate prepared by low temperature microwave annealing

    SciTech Connect

    Das, Sayantan; Alford, T. L.

    2013-06-28

    Silver doped cupric oxide thin films are prepared on polyethylene naphthalate (flexible polymer) substrates. Thin films Ag-doped CuO are deposited on the substrate by co-sputtering followed by microwave assisted oxidation of the metal films. The low temperature tolerance of the polymer substrates led to the search for innovative low temperature processing techniques. Cupric oxide is a p-type semiconductor with an indirect band gap and is used as selective absorption layer solar cells. X-ray diffraction identifies the CuO phases. Rutherford backscattering spectrometry measurements confirm the stoichiometry of each copper oxide formed. The surface morphology is determined by atomic force microscopy. The microstructural properties such as crystallite size and the microstrain for (-111) and (111) planes are calculated and discussed. Incorporation of Ag led to the lowering of band gap in CuO. Consequently, it is determined that Ag addition has a strong effect on the structural, morphological, surface, and optical properties of CuO grown on flexible substrates by microwave annealing. Tauc's plot is used to determine the optical band gap of CuO and Ag doped CuO films. The values of the indirect and direct band gap for CuO are found to be 2.02 eV and 3.19 eV, respectively.

  16. Room temperature reduction of multilayer graphene oxide film on a copper substrate: Penetration and participation of coper phase in redox reactions.

    SciTech Connect

    Voylov, Dmitry N; Agapov, Alexander L; Sokolov, Alexei P; Shulga, Y.M.; Arbuzov, Artem

    2014-01-01

    A self-reduction of graphene oxide (GO) at room temperature after prolonged storage on a copper substrate is evidenced by decrease of oxygen content and a dramatic, 6 orders in magnitude, increase in dc conductivity. Experiments revealed that the stored GO film contains copper hydroxide phase embedded in the reduced GO structure.

  17. Raman spectroscopy and electrical properties of InAs nanowires with local oxidation enabled by substrate micro-trenches and laser irradiation

    SciTech Connect

    Tanta, R.; Krogstrup, P.; Nygård, J.; Jespersen, T. S.; Madsen, M. H.; Liao, Z.; Vosch, T.

    2015-12-14

    The thermal gradients along indium arsenide nanowires were engineered by a combination of fabricated micro-trenches in the supporting substrate and focused laser irradiation. This allowed local spatial control of thermally activated oxidation reactions of the nanowire on the scale of the diffraction limit. The locality of the oxidation was detected by micro-Raman mapping, and the results were found to be consistent with numerical simulations of the temperature profile. Applying the technique to nanowires in electrical devices the locally oxidized nanowires remained conducting with a lower conductance as expected for an effectively thinner conducting core.

  18. Genetic identification of a neural circuit that suppresses appetite.

    PubMed

    Carter, Matthew E; Soden, Marta E; Zweifel, Larry S; Palmiter, Richard D

    2013-11-01

    Appetite suppression occurs after a meal and in conditions when it is unfavourable to eat, such as during illness or exposure to toxins. A brain region proposed to play a role in appetite suppression is the parabrachial nucleus, a heterogeneous population of neurons surrounding the superior cerebellar peduncle in the brainstem. The parabrachial nucleus is thought to mediate the suppression of appetite induced by the anorectic hormones amylin and cholecystokinin, as well as by lithium chloride and lipopolysaccharide, compounds that mimic the effects of toxic foods and bacterial infections, respectively. Hyperactivity of the parabrachial nucleus is also thought to cause starvation after ablation of orexigenic agouti-related peptide neurons in adult mice. However, the identities of neurons in the parabrachial nucleus that regulate feeding are unknown, as are the functionally relevant downstream projections. Here we identify calcitonin gene-related peptide-expressing neurons in the outer external lateral subdivision of the parabrachial nucleus that project to the laterocapsular division of the central nucleus of the amygdala as forming a functionally important circuit for suppressing appetite. Using genetically encoded anatomical, optogenetic and pharmacogenetic tools, we demonstrate that activation of these neurons projecting to the central nucleus of the amygdala suppresses appetite. In contrast, inhibition of these neurons increases food intake in circumstances when mice do not normally eat and prevents starvation in adult mice whose agouti-related peptide neurons are ablated. Taken together, our data demonstrate that this neural circuit from the parabrachial nucleus to the central nucleus of the amygdala mediates appetite suppression in conditions when it is unfavourable to eat. This neural circuit may provide targets for therapeutic intervention to overcome or promote appetite. PMID:24121436

  19. Genetic identification of a neural circuit that suppresses appetite

    PubMed Central

    Carter, Matthew E.; Soden, Marta E.; Zweifel, Larry S.; Palmiter, Richard D.

    2013-01-01

    Appetite suppression occurs following a meal and also during conditions when it is unfavorable to eat, such as during illness or exposure to toxins. A brain region hypothesized to play a role in appetite suppression is the parabrachial nucleus (PBN)1-3, a heterogeneous population of neurons surrounding the superior cerebellar peduncle in the brainstem. The PBN is thought to mediate the suppression of appetite induced by the anorectic hormones amylin and cholecystokinin, as well as lithium chloride and lipopolysaccharide, compounds that mimic the effects of toxic foods and bacterial infections, respectively4-6. Hyperactivity of the PBN is also thought to cause starvation following ablation of orexigenic agouti-related peptide (AgRP) neurons in adult mice1,7. However, the identities of PBN neurons that regulate feeding are unknown, as are the functionally relevant downstream projections. Here we identify calcitonin gene-related peptide (CGRP)-expressing neurons in the outer external lateral subdivision of the PBN that project to the laterocapsular division of the central nucleus of the amygdala (CeAlc) as forming a functionally important circuit for the suppression of appetite. Using genetically-encoded anatomical, optogenetic8, and pharmacogenetic9 tools, we demonstrate that activation of PBelo CGRP neurons projecting to the CeAlc suppresses appetite. In contrast, inhibition of these neurons increases food intake in circumstances when mice do not normally eat and prevents starvation in adult AgRP neuron-ablated mice. Taken together, our data demonstrate that this neural circuit from the PBN to CeAlc mediates appetite suppression in conditions when it is unfavorable to eat. This neural circuit may provide targets for therapeutic intervention to overcome or promote appetite. PMID:24121436

  20. Study of the oxidation effects on isothermal solidification based high temperature stable Pt/In/Au and Pt/In/Ag thick film interconnections on LTCC substrate

    NASA Astrophysics Data System (ADS)

    Kumar, Duguta Suresh; Suri, Nikhil; Khanna, P. K.; Sharma, R. P.

    2016-03-01

    The objective of the presented paper is to determine the oxidized phase compositions of indium lead-free solders during solidification at 190 ° C under room environment with the help of X-ray diffraction (XRD) and Energy dispersive spectroscopy (EDX). Many lead-free solders alloys available oxidizes and have poor wetting properties. The oxidation of pure indium solder foil, Au, Pt, and Ag alloys were identified and investigated, in the process of isothermal solidification based solder joints construction at room environment and humidity. Both EDX and XRD characterization techniques were performed to trace out the amount of oxide levels and variety of oxide formations at solder interface respectively. The paper also aims to report the isothermal solidification technique to provide interconnections to pads on Low temperature co-fired ceramic (LTCC) substrate. It also elaborates advantages of isothermal solidification over the other methods of interconnection. Scanning electron microscope (SEM) used to identify the oxidized spots on the surface of Pt, Ag substrates and In solder. The identified oxides were reported.

  1. Curvature aided efficient axial field emission from carbon nanofiber-reduced graphene oxide superstructures on tungsten wire substrate

    NASA Astrophysics Data System (ADS)

    Jha, Arunava; Roy, Rajarshi; Sen, Dipayan; Chattopadhyay, Kalyan K.

    2016-03-01

    Field emission characteristics found in reduced graphene oxide (RGO) and RGO based composite systems have always been an area of research interest mainly due to presence of prolific quasi aligned edges working as emitter sites. However, the specific role and extent of edge curvature geometry in RGO systems in regards to the enhancement of field emission has not discussed thoroughly prior to this work. In this work we demonstrate enhanced axial field emission due to top assembly of thin RGO layer over a quasi-vertically aligned carbon nanofiber thin film supported on a tungsten wire substrate. Furthermore, simulation analysis for our RGO based hybrid system using finite element modeling showed that two-stage local field amplification in RGO is responsible for the overall improvement of field emission characteristics. In support of our findings, a tentative explanation has been proposed based on the additional emission from RGO edges in between the CNF network resulting to the enhancement of axial field emission in the nanocomposite superstructure.

  2. Low-temperature growth of well-aligned zinc oxide nanorod arrays on silicon substrate and their photocatalytic application

    PubMed Central

    Azam, Ameer; Babkair, Saeed Salem

    2014-01-01

    Well-aligned and single-crystalline zinc oxide (ZnO) nanorod arrays were grown on silicon (Si) substrate using a wet chemical route for the photodegradation of organic dyes. Structural analysis using X-ray diffraction, high-resolution transmission electron microscopy, and selected area electron diffraction confirmed the formation of ZnO nanorods grown preferentially oriented in the (001) direction and with a single phase nature with a wurtzite structure. Field emission scanning electron microscopy and transmission electron microscopy micrographs showed that the length and diameter of the well-aligned rods were about ~350–400 nm and ~80–90 nm, respectively. Raman scattering spectra of ZnO nanorod arrays revealed the characteristic E2 (high) mode that is related to the vibration of oxygen atoms in the wurtzite ZnO. The photodegradation of methylene blue (MB) using ZnO nanorod arrays was performed under ultraviolet light irradiation. The results of photodegradation showed that ZnO nanorod arrays were capable of degrading ~80% of MB within 60 minutes of irradiation, whereas ~92% of degradation was achieved in 120 minutes. Complete degradation of MB was observed after 270 minutes of irradiation time. Owing to enhanced photocatalytic degradation efficiency and low-temperature growth method, prepared ZnO nanorod arrays may open up the possibility for the successful utilization of ZnO nanorod arrays as a future photocatalyst for environmental remediation. PMID:24812511

  3. Structure-Based Alteration of Substrate Specificity and Catalytic Activity of Sulfite Oxidase from Sulfite Oxidation to Nitrate Reduction

    SciTech Connect

    Qiu, James A.; Wilson, Heather L.; Rajagopalan, K.V.

    2012-04-18

    Eukaryotic sulfite oxidase is a dimeric protein that contains the molybdenum cofactor and catalyzes the metabolically essential conversion of sulfite to sulfate as the terminal step in the metabolism of cysteine and methionine. Nitrate reductase is an evolutionarily related molybdoprotein in lower organisms that is essential for growth on nitrate. In this study, we describe human and chicken sulfite oxidase variants in which the active site has been modified to alter substrate specificity and activity from sulfite oxidation to nitrate reduction. On the basis of sequence alignments and the known crystal structure of chicken sulfite oxidase, two residues are conserved in nitrate reductases that align with residues in the active site of sulfite oxidase. On the basis of the crystal structure of yeast nitrate reductase, both positions were mutated in human sulfite oxidase and chicken sulfite oxidase. The resulting double-mutant variants demonstrated a marked decrease in sulfite oxidase activity but gained nitrate reductase activity. An additional methionine residue in the active site was proposed to be important in nitrate catalysis, and therefore, the triple variant was also produced. The nitrate reducing ability of the human sulfite oxidase triple mutant was nearly 3-fold greater than that of the double mutant. To obtain detailed structural data for the active site of these variants, we introduced the analogous mutations into chicken sulfite oxidase to perform crystallographic analysis. The crystal structures of the Mo domains of the double and triple mutants were determined to 2.4 and 2.1 {angstrom} resolution, respectively.

  4. Epitaxial growth of highly-crystalline spinel ferrite thin films on perovskite substrates for all-oxide devices.

    PubMed

    Moyer, Jarrett A; Gao, Ran; Schiffer, Peter; Martin, Lane W

    2015-01-01

    The potential growth modes for epitaxial growth of Fe3O4 on SrTiO3 (001) are investigated through control of the energetics of the pulsed-laser deposition growth process (via substrate temperature and laser fluence). We find that Fe3O4 grows epitaxially in three distinct growth modes: 2D-like, island, and 3D-to-2D, the last of which is characterized by films that begin growth in an island growth mode before progressing to a 2D growth mode. Films grown in the 2D-like and 3D-to-2D growth modes are atomically flat and partially strained, while films grown in the island growth mode are terminated in islands and fully relaxed. We find that the optimal structural, transport, and magnetic properties are obtained for films grown on the 2D-like/3D-to-2D growth regime boundary. The viability for including such thin films in perovskite-based all-oxide devices is demonstrated by growing a Fe3O4/La0.7Sr0.3MnO3 spin valve epitaxially on SrTiO3. PMID:26030835

  5. Epitaxial growth of highly-crystalline spinel ferrite thin films on perovskite substrates for all-oxide devices

    PubMed Central

    Moyer, Jarrett A.; Gao, Ran; Schiffer, Peter; Martin, Lane W.

    2015-01-01

    The potential growth modes for epitaxial growth of Fe3O4 on SrTiO3 (001) are investigated through control of the energetics of the pulsed-laser deposition growth process (via substrate temperature and laser fluence). We find that Fe3O4 grows epitaxially in three distinct growth modes: 2D-like, island, and 3D-to-2D, the last of which is characterized by films that begin growth in an island growth mode before progressing to a 2D growth mode. Films grown in the 2D-like and 3D-to-2D growth modes are atomically flat and partially strained, while films grown in the island growth mode are terminated in islands and fully relaxed. We find that the optimal structural, transport, and magnetic properties are obtained for films grown on the 2D-like/3D-to-2D growth regime boundary. The viability for including such thin films in perovskite-based all-oxide devices is demonstrated by growing a Fe3O4/La0.7Sr0.3MnO3 spin valve epitaxially on SrTiO3. PMID:26030835

  6. Electrophoretic-deposited novel ternary silk fibroin/graphene oxide/hydroxyapatite nanocomposite coatings on titanium substrate for orthopedic applications

    NASA Astrophysics Data System (ADS)

    Li, Ming; Xiong, Pan; Mo, Maosong; Cheng, Yan; Zheng, Yufeng

    2016-06-01

    The combination of graphene oxide (GO) with robust mechanical property, silk fibroin (SF) with fascinating biological effects and hydroxyapatite (HA) with superior osteogenic activity is a competitive approach to make novel coatings for orthopedic applications. Herein, the feasibility of depositing ternary SF/GO/HA nanocomposite coatings on Ti substrate was firstly verified by exploiting electrophoretic nanotechnology, with SF being used as both a charging additive and a dispersion agent. The surface morphology, microstructure and composition, in vitro hemocompatibility and in vitro cytocompatibility of the resulting coatings were investigated by SEM, Raman, FTIR spectra and biocompatibility tests. Results demonstrated that GO, HA and SF could be co-deposited with a uniform, smooth thin-film morphology. The hemolysis rate analysis and the platelet adhesion test indicated good blood compatibility of the coatings. The human osteosarcoma MG63 cells displayed well adhesion and proliferation behaviors on the prepared coatings, with enhanced ALP activities. The present study suggested that SF/GO/HA nanocomposite coatings could be a promising candidate for the surface functionalization of biomaterials, especially as orthopedic implant coating.

  7. Electrophoretic-deposited novel ternary silk fibroin/graphene oxide/hydroxyapatite nanocomposite coatings on titanium substrate for orthopedic applications

    NASA Astrophysics Data System (ADS)

    Li, Ming; Xiong, Pan; Mo, Maosong; Cheng, Yan; Zheng, Yufeng

    2016-09-01

    The combination of graphene oxide (GO) with robust mechanical property, silk fibroin (SF) with fascinating biological effects and hydroxyapatite (HA) with superior osteogenic activity is a competitive approach to make novel coatings for orthopedic applications. Herein, the feasibility of depositing ternary SF/GO/HA nanocomposite coatings on Ti substrate was firstly verified by exploiting electrophoretic nanotechnology, with SF being used as both a charging additive and a dispersion agent. The surface morphology, microstructure and composition, in vitro hemocompatibility and in vitro cytocompatibility of the resulting coatings were investigated by SEM, Raman, FTIR spectra and biocompatibility tests. Results demonstrated that GO, HA and SF could be co-deposited with a uniform, smooth thin-film morphology. The hemolysis rate analysis and the platelet adhesion test indicated good blood compatibility of the coatings. The human osteosarcoma MG63 cells displayed well adhesion and proliferation behaviors on the prepared coatings, with enhanced ALP activities. The present study suggested that SF/GO/HA nanocomposite coatings could be a promising candidate for the surface functionalization of biomaterials, especially as orthopedic implant coating.

  8. Specific food structures supress appetite through reduced gastric emptying rate

    PubMed Central

    Rafiee, Hameed; Malcolm, Paul; Salt, Louise; van Aken, George

    2013-01-01

    The aim of this study was to determine the extent to which gastric layering and retention of a meal could be used to reduce appetite using the same caloric load. Liquid (control) and semi-solid (active) meals were produced with the same protein, fat, carbohydrate, and mass. These were fed to 10 volunteers on separate days in a crossover study, and subjective appetite ratings, gastric contents, and plasma cholecystokinin (CCK) were assessed over a period of 3 h. The active meal showed food boluses in the stomach persisting for ∼45 min, slower emptying rates, and lower plasma CCK levels over the first hour. After the first hour, both gastric emptying rates and plasma CCK levels were similar for both systems and slightly increased compared with the unfed situation. Despite the lower plasma CCK levels for the active meal over the first hour, this meal reduced appetite more than the control meal over the 3 h of the study. For a moderately increased plasma CCK level in the fed state, appetite was correlated with the volume of gastric contents rather than gastric emptying rates or plasma CCK. This suggests that enhanced gastric retention was the key factor in decreasing appetite and was probably mediated by a combination of intestinal nutrient sensing and increased viscosity in the stomach. PMID:23578786

  9. Energy expenditure and substrate oxidation in patients with cirrhosis: the impact of cause, clinical staging and nutritional state.

    PubMed

    Müller, M J; Lautz, H U; Plogmann, B; Bürger, M; Körber, J; Schmidt, F W

    1992-05-01

    Many clinicians subjectively feel that cirrhotic patients frequently have clinical signs of hypermetabolism. However, it is unknown whether hypermetabolism is a constant feature of chronic liver disease, corresponds to liver destruction and repair or is of prognostic value. This article is about resting energy expenditure and substrate oxidation rates in 123 patients with biopsy-proven cirrhosis differing with respect to cause, duration of the disease, biochemical parameters of parenchymal cell damage, cholestasis, liver function, number of complications, clinical staging and nutritional state. Resting energy expenditure varied between 1,090 and 2,300 kcal/day and differed from the predicted values in 70% of the patients. Resting energy expenditure was closely related to fat-free mass, and 52% of the variability could be explained by fat-free mass, age and sex. Of all the patients, 18% were hypermetabolic and 31% were hypometabolic. Hypermetabolism showed no strict association with the cause of cirrhosis, the duration of the disease, liver function, cholestasis, cell damage, clinical staging, blood hemoglobin, plasma thyroid hormone levels or human leukocyte antigens. An increased resting energy expenditure was associated with significant losses of muscle, body cell mass and extracellular mass at unchanged body fat, whereas fat and fat-free mass were increased in hypometabolic patients when compared with normometabolic patients. Lipid oxidation was increased, but glucose oxidation was reduced in nearly all patients with cirrhosis. This was most pronounced at advanced stages of liver disease. Although similar with respect to liver function and clinical staging, 76.2% of hypermetabolic patients had transplants within the observation period, compared with only 16.7% and 8.1% in the normometabolic group and hypometabolic group, respectively. Posttransplantation mortality was independent of pretransplantation resting energy expenditure, but it increased significantly in

  10. Dioxygen-Initiated Oxidation of Heteroatomic Substrates Incorporated into Ancillary Pyridine Ligands of Carboxylate-Rich Diiron(II) Complexes

    PubMed Central

    Carson, Emily C.; Lippard, Stephen J.

    2008-01-01

    Progress toward the development of functional models of the carboxylate-bridged diiron active site in soluble methane monooxygenase is described in which potential substrates are introduced as substituents on bound pyridine ligands. Thiol, sulfide, sulfoxide, and phosphine moieties incorporated into a pyridine ligand were allowed to react with the preassembled diiron(II) complex [Fe2(μ-O2CArR)2(O2CArR)2(THF)2], where -O2CArR is a sterically hindered 2,6-di(p-tolyl)- or 2,6-di(p-fluorophenyl)benzoate (R = Tol or 4-FPh). The resulting diiron(II) complexes were characterized crystallographically. Triply- and doubly-bridged compounds [Fe2(μ-O2CArTol)3(O2CArTol)(2-MeSpy)] (4) and [Fe2(μ-O2CArTol)2(O2CArTol)2(2-MeS(O)py)2] (5) resulted when 2-methylthiopyridine (2-MeSpy) and 2-pyridylmethylsulfoxide (2-MeS(O)py), respectively, were employed. Another triply-bridged diiron(II) complex, [Fe2(μ-O2CAr4-FPh)3(O2CAr4-FPh)(2-Ph2Ppy)] (3), was obtained containing 2-diphenylphosphinopyridine (2-Ph2Ppy). Use of 2-mercaptopyridine (2-HSpy) afforded the mononuclear complex [Fe(O2CArTol)2(2-HSpy)2] (6a). Together with that of previously reported [Fe2(μ-O2CArTol)3(O2CArTol)(2-PhSpy)] (2) and [Fe2(μ-O2CArTol)3(O2CArTol)(2-Ph2Ppy)] (1), the dioxygen reactivity of these iron(II) complexes was investigated. A dioxygen-dependent intermediate (6b) formed upon exposure of 6a to O2, the electronic structure of which was probed by various spectroscopic methods. Exposure of 4 and 5 to dioxygen revealed both sulfide and sulfoxide oxidation. Oxidation of 3 in CH2Cl2 affords [Fe2(μ-OH)2(μ-O2CAr4-FPh)(O2CAr4-FPh)3(OH2)(2-Ph2P(O)py)] (8), which contains the biologically relevant {Fe2(μ-OH)2(μ-O2CR)}3+ core. This reaction is sensitive to the choice of carboxylate ligands, however, since the p-tolyl analog 1 yielded a hexanuclear species, 7, upon oxidation. PMID:16411722

  11. Appetitive Aggression as a Resilience Factor against Trauma Disorders: Appetitive Aggression and PTSD in German World War II Veterans

    PubMed Central

    Weierstall, Roland; Huth, Sina; Knecht, Jasmin; Nandi, Corina; Elbert, Thomas

    2012-01-01

    Background Repeated exposure to traumatic stressors such as combat results in chronic symptoms of PTSD. However, previous findings suggest that former soldiers who report combat-related aggression to be appetitive are more resilient to develop PTSD. Appetitive Aggression should therefore prevent widespread mental suffering in perpetrators of severe atrocities even after decades. Methods and Findings To test the long-term relationship between trauma-related illness and attraction to aggression, we surveyed a sample of 51 German male World-War II veterans (age: M = 86.7, SD = 2.8). War-related appetitive aggression was assessed with the Appetitive Aggression Scale (AAS). Current- and lifetime PTSD symptoms were assessed with the PSS-I. In a linear regression analysis accounting for 31% of the variance we found that veterans that score higher on the AAS show lower PSS-I symptom severity scores across their whole post-war lifetime (β = − .31, p = .014). The effect size and power were sufficient (f2 = 0.51, (1-β) = .99). The same was true for current PTSD (β = − .27, p = .030). Conclusions Appetitive Aggression appears to be a resilience factor for negative long-term effects of combat experiences in perpetrators of violence. This result has practical relevance for preventing trauma-related mental suffering in Peace Corps and for designing adequate homecoming reception for veterans. PMID:23251398

  12. Use of human wastes oxidized to different degrees in cultivation of higher plants on the soil-like substrate intended for closed ecosystems

    NASA Astrophysics Data System (ADS)

    Tikhomirov, A. A.; Kudenko, Yu. A.; Ushakova, S. A.; Tirranen, L. S.; Gribovskaya, I. A.; Gros, J.-B.; Lasseur, Ch.

    2010-09-01

    To close mass exchange loops in bioregenerative life support systems more efficiently, researchers of the Institute of Biophysics SB RAS (Krasnoyarsk, Russia) have developed a procedure of wet combustion of human wastes and inedible parts of plants using H 2O 2 in alternating electromagnetic field. Human wastes pretreated in this way can be used as nutrient solutions to grow plants in the phototrophic unit of the LSS. The purpose of this study was to explore the possibilities of using human wastes oxidized to different degrees to grow plants cultivated on the soil-like substrate (SLS). The treated human wastes were analyzed to test their sterility. Then we investigated the effects produced by human wastes oxidized to different degrees on growth and development of wheat plants and on the composition of microflora in the SLS. The irrigation solution contained water, substances extracted from the substrate, and certain amounts of the mineralized human wastes. The experiments showed that the human wastes oxidized using reduced amounts of 30% H 2O 2: 1 ml/g of feces and 0.25 ml/ml of urine were still sterile. The experiments with wheat plants grown on the SLS and irrigated by the solution containing treated human wastes in the amount simulating 1/6 of the daily diet of a human showed that the degree of oxidation of human wastes did not significantly affect plant productivity. On the other hand, the composition of the microbiota of irrigation solutions was affected by the oxidation level of the added metabolites. In the solutions supplemented with partially oxidized metabolites yeast-like microscopic fungi were 20 times more abundant than in the solutions containing fully oxidized metabolites. Moreover, in the solutions containing incompletely oxidized human wastes the amounts of phytopathogenic bacteria and denitrifying microorganisms were larger. Thus, insufficiently oxidized sterile human wastes added to the irrigation solutions significantly affect the composition of

  13. Appetite Loss and Neurocognitive Deficits in Late-Life Depression

    PubMed Central

    Potter, Guy G.; McQuoid, Douglas R.; Steffens, David C.

    2015-01-01

    Objectives Examine association of appetite loss symptoms to neurocognitive performance in late-life depression (LLD). Methods Cross-sectional data from individuals aged 60+ with Major Depressive Disorder (N =322). Participants received clinical assessment of depression and neuropsychological testing. Factor analysis was used to characterize depression symptom factors, and composite scales were developed for episodic memory, psychomotor executive functions, verbal fluency, and working memory span. Results Factor analysis produced a five-factor solution: (1) Anhedonia/Sadness, (2) Suicidality/Guilt, (3) Appetite/Weight Loss, (4) Sleep Disturbance, and (5) Anxiety/Tension. In separate multivariate models for each neurocognitive domain and including all 5 depression factors, higher appetite-loss-related symptoms were associated with lower performance in episodic memory, psychomotor executive functions, and verbal fluency; results were significant with covariates of age, education, race, sex, age of depression onset, and illness burden. No other depression factors were associated with neurocognitive performance in these models. In an additional set of models, the Appetite factor mediated the association between global depression severity and neurocognitive performance. Discussion A factor of appetite and weight loss symptoms in LLD was uniquely associated with neurocognitive performance, in contrast to lack of association among other depression symptom factors. Conclusion Cognitive deficits are a major adverse outcome of LLD, and prominent appetite loss during acute depression may be a marker for these deficits, independent of overall depression severity. Research is needed to understand the mechanisms that may explain this association, and how it is related to the cognitive and symptomatic course of LLD. PMID:25315155

  14. Appetite and falls: Old age and lived experiences

    PubMed Central

    Sarvimäki, Anneli

    2012-01-01

    Falling among older adults is a well-known public health problem but the association between falling and appetite is seldom studied although poor nutritional status is accepted as a risk factor for falls. On this background the aim of this study was to understand how older adults, who have fallen several times within a year, related their experiences of appetite as a phenomenon in everyday life. In narrative in-depth interviews, eight women and four men contributed with their stories. Using interpretative phenomenology the thematic analysis resulted in three main themes: appetite for food; appetite for social relations and appetite for influence. Eating was not trivial everyday routine and required self-regimentation. Meals were not an object of desire, but of discipline out of the wish to survive. Feelings, reflections and ambivalence were bound to the lack of appetite on food. The participants were oriented towards the forbidden, the delicious and to everyday food as a strengthener and as medicine. In their dependency on help, home was the framework for establishing social relations as means of social support. As well as family and neighbours, the significant others were persons on whom the participants were dependent. Personal relationships and mutual dependencies may ensure social security in lives characterised by contingency and maintain influence in daily life. Falling is both a dramatic and a trivial incident where life and death could be at stake. From this perspective, connectedness was prominent in all fall stories. The quest for influence and a sense of social connectedness was the incentive to re-enter local community arenas and to express solidarity. In health-care practice multi-factorial fall-prevention should be complemented with a multi-dimensional approach in order to balance the medical approach with humanistic and societal approaches towards fall-prevention. PMID:22389651

  15. Specific Appetite for Carotenoids in a Colorful Bird

    PubMed Central

    Senar, Juan Carlos; Møller, Anders Pape; Ruiz, Iker; Negro, Juan José; Broggi, Juli; Hohtola, Esa

    2010-01-01

    Background Since carotenoids have physiological functions necessary for maintaining health, individuals should be selected to actively seek and develop a specific appetite for these compounds. Methodology/Principal Findings Great tits Parus major in a diet choice experiment, both in captivity and the field, preferred carotenoid-enriched diets to control diets. The food items did not differ in any other aspects measured besides carotenoid content. Conclusions/Significance Specific appetite for carotenoids is here demonstrated for the first time, placing these compounds on a par with essential nutrients as sodium or calcium. PMID:20502717

  16. Differential recruitment of distinct amygdalar nuclei across appetitive associative learning

    PubMed Central

    Cole, Sindy; Powell, Daniel J.; Petrovich, Gorica D.

    2013-01-01

    The amygdala is important for reward-associated learning, but how distinct cell groups within this heterogeneous structure are recruited during appetitive learning is unclear. Here we used Fos induction to map the functional amygdalar circuitry recruited during early and late training sessions of Pavlovian appetitive conditioning. We found that a number of distinct amygdalar nuclei were differentially recruited by tone–food pairings during the early and late stages of training, suggesting evidence of learning-induced plasticity. Notably, these selectively activated nuclei belong to dissociable subsystems that are well placed to simultaneously inform cortical (cognitive) processing and behavioral control during tone–food learning. PMID:23676201

  17. The role of short chain fatty acids in appetite regulation and energy homeostasis

    PubMed Central

    Byrne, C S; Chambers, E S; Morrison, D J; Frost, G

    2015-01-01

    Over the last 20 years there has been an increasing interest in the influence of the gastrointestinal tract on appetite regulation. Much of the focus has been on the neuronal and hormonal relationship between the gastrointestinal tract and the brain. There is now mounting evidence that the colonic microbiota and their metabolic activity have a significant role in energy homeostasis. The supply of substrate to the colonic microbiota has a major impact on the microbial population and the metabolites they produce, particularly short chain fatty acids (SCFAs). SCFAs are produced when non-digestible carbohydrates, namely dietary fibres and resistant starch, undergo fermentation by the colonic microbiota. Both the consumption of fermentable carbohydrates and the administration of SCFAs have been reported to result in a wide range of health benefits including improvements in body composition, glucose homeostasis, blood lipid profiles and reduced body weight and colon cancer risk. However, published studies tend to report the effects that fermentable carbohydrates and SCFAs have on specific tissues and metabolic processes, and fail to explain how these local effects translate into systemic effects and the mitigation of disease risk. Moreover, studies tend to investigate SCFAs collectively and neglect to report the effects associated with individual SCFAs. Here, we bring together the recent evidence and suggest an overarching model for the effects of SCFAs on one of their beneficial aspects: appetite regulation and energy homeostasis. PMID:25971927

  18. Low-Temperature Oxidation-Free Selective Laser Sintering of Cu Nanoparticle Paste on a Polymer Substrate for the Flexible Touch Panel Applications.

    PubMed

    Kwon, Jinhyeong; Cho, Hyunmin; Eom, Hyeonjin; Lee, Habeom; Suh, Young Duk; Moon, Hyunjin; Shin, Jaeho; Hong, Sukjoon; Ko, Seung Hwan

    2016-05-11

    Copper nanomaterials suffer from severe oxidation problem despite the huge cost effectiveness. The effect of two different processes for conventional tube furnace heating and selective laser sintering on copper nanoparticle paste is compared in the aspects of chemical, electrical and surface morphology. The thermal behavior of the copper thin films by furnace and laser is compared by SEM, XRD, FT-IR, and XPS analysis. The selective laser sintering process ensures low annealing temperature, fast processing speed with remarkable oxidation suppression even in air environment while conventional tube furnace heating experiences moderate oxidation even in Ar environment. Moreover, the laser-sintered copper nanoparticle thin film shows good electrical property and reduced oxidation than conventional thermal heating process. Consequently, the proposed selective laser sintering process can be compatible with plastic substrate for copper based flexible electronics applications. PMID:27128365

  19. Utilization of Anodized Aluminum Oxide Substrate for the Growth of ZnO Microcrystals on Polygonized Spirals

    NASA Astrophysics Data System (ADS)

    Deulkar, Sundeep H.; Bhosale, C. H.; Huang, Jow-Lay

    2015-04-01

    Anodized Aluminum Oxide (AAO) has been utilized as a substrate for the screw dislocation assisted growth of polygonize spirals (PS) of ZnO with diameter of the order of 230 μm by Chemical Vapour Deposition (CVD) process. Stoichiometric ZnO microcrystals nucleated on the terraces and tops of these polygonized spirals. Stress inherent in the ZnO polygonized spiral morphology ( 3.57 GPa) was deciphered from the values of the magnitude of shift in observed 2θ values of Glancing Incidence angle XRD (GIXRD) peaks from the standard values (JCPDS 36-1451) for hexagonal Zincite. The growth mechanism of these PS was explained albeit to a limited extent on the basis of the Burton, Cabrera and Frank (BCF) theory and its later modification, wherein data obtained from exsitu SEM measurements concomitant with numerical analysis was utilized to decipher values of the critical radius and supersaturation ratios. Nucleation of ZnO microcrystals on the PS was explained on the basis of the supersaturation ratio and the plausible values of diffusion lengths, existent on the summits of these PS. Retardation of the step rotation of the PS, due to elastic stress around the dislocation source and the Gibbs-Thomson effect, was explained on the basis of numerical coefficient ω0, the dimensionless frequency of spiral rotation. Role of stress in inhibition of ZnO nucleation on PS of smaller heights and with larger supersaturation ratio, has been discussed albeit qualitatively. The optical characteristics of a single ZnO microcrystal has been analyzed by room temperature CL measurements in the wavelength range 350 nm to 650 nm, revealing a single high intensity peak at 382 nm corresponding to a excitonic bandgap of 3.25 eV.

  20. Electrical and physicochemical properties of atomic-layer-deposited HfO2 film on Si substrate with interfacial layer grown by nitric acid oxidation

    NASA Astrophysics Data System (ADS)

    Kim, Seung Hyun; Seok, Tae Jun; Jin, Hyun Soo; Kim, Woo-Byoung; Park, Tae Joo

    2016-03-01

    The ultrathin SiO2 interfacial layer (IL) was adopted at the interface between atomic-layer-deposited HfO2 gate dielectric film and a Si substrate, which was grown using nitric acid oxidation (NAO) and O3 oxidation (OZO) prior to HfO2 film deposition. X-ray photoelectron spectroscopy result revealed that Si diffusion from the substrate into the film was suppressed for the film with NAO compared to that with OZO, which was attributed to the higher physical density of IL. The electrical measurement using metal-insulator-semiconductor devices showed that the film with NAO exhibited higher effective permittivity and lower densities of fixed charge and slow state at the interface. Furthermore, the leakage current density at an equivalent electrical thickness was lower for the film with NAO than OZO.

  1. Plasma-enhanced atomic layer deposition of nanoscale yttria-stabilized zirconia electrolyte for solid oxide fuel cells with porous substrate.

    PubMed

    Ji, Sanghoon; Cho, Gu Young; Yu, Wonjong; Su, Pei-Chen; Lee, Min Hwan; Cha, Suk Won

    2015-02-11

    Nanoscale yttria-stabilized zirconia (YSZ) electrolyte film was deposited by plasma-enhanced atomic layer deposition (PEALD) on a porous anodic aluminum oxide supporting substrate for solid oxide fuel cells. The minimum thickness of PEALD-YSZ electrolyte required for a consistently high open circuit voltage of 1.17 V at 500 °C is 70 nm, which is much thinner than the reported thickness of 180 nm using nonplasmatic ALD and is also the thinnest attainable value reported in the literatures on a porous supporting substrate. By further reducing the electrolyte thickness, the grain size reduction resulted in high surface grain boundary density at the cathode/electrolyte interface. PMID:25625537

  2. Study of preferred orientation of zinc oxide films on the 64 deg. LiNbO{sub 3} substrates and their applications as liquid sensors

    SciTech Connect

    Jian, S.-J.; Chu, S.-Y.; Huang, T.-Y.; Water, Walter

    2004-11-01

    The preferred (002) orientation of zinc oxide (ZnO) films has been grown and demonstrated on 64 deg. LiNbO{sub 3} substrates using a rf magnetron sputtering system. The film orientations and crystallinity are strongly dependent on the rf power, total chamber pressure, ratio of argon to oxygen, and substrate temperature. We investigated the crystalline structure of the films by x-ray diffraction and scanning electron microscopy. Highly oriented (002) films were obtained under a total chamber pressure of 1.33 Pa, containing 40% oxygen and 60% argon, and a substrate temperature around 120 deg. C. Love-wave devices based on this structure (ZnO/IDTs/64 deg. LiNbO{sub 3}) are presented.

  3. The effect of substrate temperature on the microstructural, electrical and optical properties of Sn-doped indium oxide thin films

    NASA Astrophysics Data System (ADS)

    Raoufi, Davood; Taherniya, Atefeh

    2015-06-01

    In this work, Sn doping In2O3 (ITO) thin films with a thickness of 200 nm were deposited on glass substrates by electron beam evaporation (EBE) method at different substrate temperatures. The crystal structure of these films was studied by X-ray diffraction technique. The sheet resistance was measured by a four-point probe. Van der Pauw method was used to measure carrier density and mobility of ITO films. The optical transmittance spectra were recorded in the wavelength region of 300-800 nm. Scanning electron microscope (SEM) has been used for the surface morphology analysis. The prepared ITO films exhibited body-centered cubic (BCC) structure with preferred orientation of growth along the (2 2 2) crystalline plane. The grain size of the films increases by rising the substrate temperature. Transparency of the films, over the visible light region, is increased with increasing the substrate temperature. It is found that the electrical properties of ITO films are significantly affected by substrate temperature. The electrical resistivity decreases with increasing substrate temperature, whereas the carrier density and mobility are enhanced with an increase in substrate temperature. The evaluated values of energy band gap Eg for ITO films were increase from 3.84 eV to 3.91 eV with increasing the substrate temperatures from 200 °C to 500 °C. The SEM micrographs of the films revealed a homogeneous growth without perceptible cracks with particles which are well covered on the substrate.

  4. Universal Relationship between Substrate Current and History Effect in Silicon-on-Insulator Metal-Oxide-Semiconductor Field-Effect Transistors

    NASA Astrophysics Data System (ADS)

    Amakawa, Shuhei; Toda, Asato; Ohyama, Katsuroh; Higashiguchi, Naoya; Hori, Daisuke; Shintaku, Yasuhiro; Miyake, Masataka; Miura-Mattausch, Mitiko

    2011-04-01

    This paper presents an experimentally found device-size-independent universal relationship between the settling time of floating-body silicon-on-insulator (SOI) metal-oxide-semiconductor field-effect transistors (MOSFETs) and the substrate current in body-tied devices. Such a relationship could enable one to characterize dynamic properties of SOI MOSFETs through DC measurements and would be useful for physical compact modeling of history effects.

  5. An Appetitive Conditioned Stimulus Enhances Fear Acquisition and Impairs Fear Extinction

    ERIC Educational Resources Information Center

    Leung, Hiu T.; Holmes, Nathan M.; Westbrook, R. Frederick

    2016-01-01

    Four experiments used between- and within-subject designs to examine appetitive-aversive interactions in rats. Experiments 1 and 2 examined the effect of an excitatory appetitive conditioned stimulus (CS) on acquisition and extinction of conditioned fear. In Experiment 1, a CS shocked in a compound with an appetitive excitor (i.e., a stimulus…

  6. Charge transfer from an adsorbed ruthenium-based photosensitizer through an ultra-thin aluminium oxide layer and into a metallic substrate

    SciTech Connect

    Gibson, Andrew J.; Temperton, Robert H.; Handrup, Karsten; Weston, Matthew; Mayor, Louise C.; O’Shea, James N.

    2014-06-21

    The interaction of the dye molecule N3 (cis-bis(isothiocyanato)bis(2,2-bipyridyl-4,4′-dicarbo-xylato) -ruthenium(II)) with the ultra-thin oxide layer on a AlNi(110) substrate, has been studied using synchrotron radiation based photoelectron spectroscopy, resonant photoemission spectroscopy, and near edge X-ray absorption fine structure spectroscopy. Calibrated X-ray absorption and valence band spectra of the monolayer and multilayer coverages reveal that charge transfer is possible from the molecule to the AlNi(110) substrate via tunnelling through the ultra-thin oxide layer and into the conduction band edge of the substrate. This charge transfer mechanism is possible from the LUMO+2 and 3 in the excited state but not from the LUMO, therefore enabling core-hole clock analysis, which gives an upper limit of 6.0 ± 2.5 fs for the transfer time. This indicates that ultra-thin oxide layers are a viable material for use in dye-sensitized solar cells, which may lead to reduced recombination effects and improved efficiencies of future devices.

  7. Charge transfer from an adsorbed ruthenium-based photosensitizer through an ultra-thin aluminium oxide layer and into a metallic substrate

    NASA Astrophysics Data System (ADS)

    Gibson, Andrew J.; Temperton, Robert H.; Handrup, Karsten; Weston, Matthew; Mayor, Louise C.; O'Shea, James N.

    2014-06-01

    The interaction of the dye molecule N3 (cis-bis(isothiocyanato)bis(2,2-bipyridyl-4,4'-dicarbo-xylato)-ruthenium(II)) with the ultra-thin oxide layer on a AlNi(110) substrate, has been studied using synchrotron radiation based photoelectron spectroscopy, resonant photoemission spectroscopy, and near edge X-ray absorption fine structure spectroscopy. Calibrated X-ray absorption and valence band spectra of the monolayer and multilayer coverages reveal that charge transfer is possible from the molecule to the AlNi(110) substrate via tunnelling through the ultra-thin oxide layer and into the conduction band edge of the substrate. This charge transfer mechanism is possible from the LUMO+2 and 3 in the excited state but not from the LUMO, therefore enabling core-hole clock analysis, which gives an upper limit of 6.0 ± 2.5 fs for the transfer time. This indicates that ultra-thin oxide layers are a viable material for use in dye-sensitized solar cells, which may lead to reduced recombination effects and improved efficiencies of future devices.

  8. Preparation of a well-defined amino-terminated self-assembled monolayer and copper microlines on a polyimide substrate covered with an oxide nanoskin.

    PubMed

    Hozumi, Atsushi; Asakura, Shuichi; Fuwa, Akio; Shirahata, Naoto; Kameyama, Tetsuya

    2005-08-30

    A well-ordered, uniform amino (NH(2))-terminated organosilane self-assembled monolayer (SAM) was prepared on a polyimide (PI) substrate, the surface of which had silica-like reactivity. First, through chemical vapor deposition of 1,3,5,7-tetramethylcyclotetrasiloxane and subsequent photooxidation using 172 nm vacuum ultraviolet light, an extremely thin silicon dioxide (SiO(2)) layer about 1 nm thick, which we call an "oxide nanoskin" (ONS), was prepared on a PI substrate. Due to the presence of this ONS layer, the PI surface's properties became almost identical with those of Si covered with native oxide (SiO(2)/Si) without any marked change in surface morphology, as evidenced by zeta-potential measurements, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). Next, this ONS-covered PI (ONS/PI) surface was exposed to vapor of a 12.5 vol % solution of N-(6-aminohexyl)(3-aminopropyl)trimethoxysilane (AHAPS) molecules diluted with absolute toluene. On the basis of contact angle analysis, the surface energy of this AHAPS/ONS/PI sample was mostly consistent with that of a SiO(2)/Si substrate covered with an AHAPS-SAM (AHAPS/SiO(2)/Si). On the other hand, the surface energy of an AHAPS-treated PI (AHAPS/PI) substrate was much smaller than that of the AHAPS/ONS/PI substrate due to insufficient surface coverage by the AHAPS molecules. This was also confirmed by lateral force microscopy using photolithographically micropatterned samples. Fabricated micropatterns composed of AHAPS- and SiO(2)-covered regions were clearly imaged on the AHAPS/ONS/PI substrate through their difference in friction, while the friction contrast of the micropatterned AHAPS/PI substrate was unclear. This marked difference in packing density of the AHAPS molecules had a direct influence on the adsorption behavior of palladium colloids and subsequent electroless plating of copper (Cu). As confirmed by AFM and XPS, metallization proceeded only on the AHAPS-covered regions, while

  9. APPETITE CONTROL: METHODOLOGICAL ASPECTS OF THE EVALUATION OF FOODS

    PubMed Central

    Blundell, John; de Graaf, Cees; Hulshof, Toine; Jebb, Susan; Livingstone, Barbara; Lluch, Anne; Mela, David; Salah, Samir; Schuring, Ewoud; van der Knaap, Henk; Westerterp, Margriet

    2013-01-01

    This report describes a set of scientific procedures used to assess the impact of foods and food ingredients on the expression of appetite (psychological and behavioural). An overarching priority has been to enable potential evaluators of health claims about foods to identify justified claims, and to exclude claims that are not supported by scientific evidence for the effect cited. This priority follows precisely from the principles set down in the PASSCLAIM report. (4) The report allows the evaluation of the strength of health claims, about the effects of foods on appetite, which can be sustained on the basis of the commonly used scientific designs and experimental procedures. The report includes different designs for assessing effects on satiation as opposed to satiety,detailed coverage of the extent to which a change in hunger can stand-alone as a measure of appetite control, and an extensive discussion of the statistical procedures appropriate for handling data in this field of research. Since research in this area is continually evolving, new improved methodologies may emerge over time and will need to be incorporated into the framework. One main objective of the report has been to produce guidance on good practice in carrying out appetite research, and not to set down a series of commandments that must be followed. PMID:20122136

  10. Gender Differences in the Appetite Response to a Satiating Diet

    PubMed Central

    Bédard, Alexandra; Hudon, Anne-Marie; Drapeau, Vicky; Corneau, Louise; Dodin, Sylvie; Lemieux, Simone

    2015-01-01

    We examined gender differences in appetite sensations when exposed to Mediterranean diet (MedDiet) meals and determined whether there are gender differences in the change in the satiating properties of the MedDiet over time. Thirty-eight men and 32 premenopausal women consumed a 4-week isoenergetic MedDiet under controlled conditions. Visual analogue scales were used to measure perceived appetite sensations before and immediately after each meal consumed over the course of one day (Wednesday) of the first and the fourth week of intervention. Women reported greater decreases for desire to eat, hunger, and appetite score than men in response to the consumption of the MedDiet meals (gender-by-meal interactions, resp., P = 0.04, P = 0.048, and P = 0.03). Fullness and prospective food consumption responses did not significantly differ between men and women. Between the first and the fourth week of intervention, premeal prospective food consumption increased with time in men (P = 0.0007) but not in women (P = 0.84; P for gender-by-time interaction = 0.04). These results indicate gender differences in appetite sensations when exposed to the MedDiet. These results may be useful in order to have a better understanding of gender issues for body weight management. PMID:26442158

  11. Sensitive Periods for Developing a Robust Trait of Appetitive Aggression

    PubMed Central

    Köbach, Anke; Elbert, Thomas

    2015-01-01

    Violent behavior can be intrinsically rewarding; especially combatants fighting in current civil wars present with elevated traits of appetitive aggression. The majority of these fighters were recruited as children or adolescents. In the present study, we test whether there is a developmental period where combatants are sensitive for developing a robust trait of appetitive aggression. We investigated 95 combatants in their demobilization process that were recruited at different ages in the Kivu regions of the eastern Democratic Republic of Congo. Using random forest with conditional inference trees, we identified recruitment at the ages from 16 and 17 years as being predictive of the level of appetitive aggression; the number of lifetime, perpetrated acts was the most important predictor. We conclude that high levels of appetitive aggression develop in ex-combatants, especially in those recruited during their middle to late teenage, which is a developmental period marked by a natural inclination to exercise physical force. Consequently, ex-combatants may remain vulnerable for aggressive behavior patterns and re-recruitment unless they are provided alternative strategies for dealing with their aggression. PMID:26528191

  12. Diminished appetitive startle modulation following targeted inhibition of prefrontal cortex

    PubMed Central

    Hurlemann, René; Arndt, Stephan; Schlaepfer, Thomas E.; Reul, Juergen; Maier, Wolfgang; Scheele, Dirk

    2015-01-01

    From an evolutionary perspective the startle eye-blink response forms an integral part of the human avoidance behavioral repertoire and is typically diminished by pleasant emotional states. In major depressive disorder (MDD) appetitive motivation is impaired, evident in a reduced interference of positive emotion with the startle response. Given the pivotal role of frontostriatal neurocircuitry in orchestrating appetitive motivation, we hypothesized that inhibitory transcranial magnetic stimulation (TMS) would reduce appetitive neuromodulation in a manner similar to MDD. Based on a pre-TMS functional MRI (fMRI) experiment we selected the left dorsolateral and dorsomedial prefrontal cortices as target regions for subsequent sham-controlled inhibitory theta-burst TMS (TBS) in 40 healthy male volunteers. Consistent with our hypothesis, between-group comparisons revealed a TBS-induced inhibition of appetitive neuromodulation, manifest in a diminished startle response suppression by hedonic stimuli. Collectively, our results suggest that functional integrity of left dorsolateral and dorsomedial prefrontal cortex is critical for mediating a pleasure-induced down-regulation of avoidance responses which may protect the brain from a depressogenic preponderance of defensive stress. PMID:25752944

  13. Central Localization of Plasticity Involved in Appetitive Conditioning in "Lymnaea"

    ERIC Educational Resources Information Center

    Straub, Volko A.; Styles, Benjamin J.; Ireland, Julie S.; O'Shea, Michael; Benjamin, Paul R.

    2004-01-01

    Learning to associate a conditioned (CS) and unconditioned stimulus (US) results in changes in the processing of CS information. Here, we address directly the question whether chemical appetitive conditioning of "Lymnaea" feeding behavior involves changes in the peripheral and/or central processing of the CS by using extracellular recording…

  14. Gender Differences in the Appetite Response to a Satiating Diet.

    PubMed

    Bédard, Alexandra; Hudon, Anne-Marie; Drapeau, Vicky; Corneau, Louise; Dodin, Sylvie; Lemieux, Simone

    2015-01-01

    We examined gender differences in appetite sensations when exposed to Mediterranean diet (MedDiet) meals and determined whether there are gender differences in the change in the satiating properties of the MedDiet over time. Thirty-eight men and 32 premenopausal women consumed a 4-week isoenergetic MedDiet under controlled conditions. Visual analogue scales were used to measure perceived appetite sensations before and immediately after each meal consumed over the course of one day (Wednesday) of the first and the fourth week of intervention. Women reported greater decreases for desire to eat, hunger, and appetite score than men in response to the consumption of the MedDiet meals (gender-by-meal interactions, resp., P = 0.04, P = 0.048, and P = 0.03). Fullness and prospective food consumption responses did not significantly differ between men and women. Between the first and the fourth week of intervention, premeal prospective food consumption increased with time in men (P = 0.0007) but not in women (P = 0.84; P for gender-by-time interaction = 0.04). These results indicate gender differences in appetite sensations when exposed to the MedDiet. These results may be useful in order to have a better understanding of gender issues for body weight management. PMID:26442158

  15. Hindbrain serotonin and the rapid induction of sodium appetite

    NASA Technical Reports Server (NTRS)

    Menani, J. V.; De Luca, L. A. Jr; Thunhorst, R. L.; Johnson, A. K.

    2000-01-01

    Both systemically administered furosemide and isoproterenol produce water intake (i.e., thirst). Curiously, however, in light of the endocrine and hemodynamic effects produced by these treatments, they are remarkably ineffective in eliciting intake of hypertonic saline solutions (i.e., operationally defined as sodium appetite). Recent work indicates that bilateral injections of the serotonin receptor antagonist methysergide into the lateral parabrachial nuclei (LPBN) markedly enhance a preexisting sodium appetite. The present studies establish that a de novo sodium appetite can be induced with LPBN-methysergide treatment under experimental conditions in which only water is typically ingested. The effects of bilateral LPBN injections of methysergide were studied on the intake of water and 0. 3 M NaCl following acute (beginning 1 h after treatment) diuretic (furosemide)-induced sodium and water depletion and following subcutaneous isoproterenol treatment. With vehicle injected into the LPBN, furosemide treatment and isoproterenol injection both caused water drinking but essentially no intake of hypertonic saline. In contrast, bilateral treatment of the LPBN with methysergide induced the intake of 0.3 M NaCl after subcutaneous furosemide and isoproterenol. Water intake induced by subcutaneous furosemide or isoproterenol was not changed by LPBN-methysergide injections. The results indicate that blockade of LPBN-serotonin receptors produces a marked intake of hypertonic NaCl (i.e., a de novo sodium appetite) after furosemide treatment as well as subcutaneous isoproterenol.

  16. Diminished appetitive startle modulation following targeted inhibition of prefrontal cortex.

    PubMed

    Hurlemann, René; Arndt, Stephan; Schlaepfer, Thomas E; Reul, Juergen; Maier, Wolfgang; Scheele, Dirk

    2015-01-01

    From an evolutionary perspective the startle eye-blink response forms an integral part of the human avoidance behavioral repertoire and is typically diminished by pleasant emotional states. In major depressive disorder (MDD) appetitive motivation is impaired, evident in a reduced interference of positive emotion with the startle response. Given the pivotal role of frontostriatal neurocircuitry in orchestrating appetitive motivation, we hypothesized that inhibitory transcranial magnetic stimulation (TMS) would reduce appetitive neuromodulation in a manner similar to MDD. Based on a pre-TMS functional MRI (fMRI) experiment we selected the left dorsolateral and dorsomedial prefrontal cortices as target regions for subsequent sham-controlled inhibitory theta-burst TMS (TBS) in 40 healthy male volunteers. Consistent with our hypothesis, between-group comparisons revealed a TBS-induced inhibition of appetitive neuromodulation, manifest in a diminished startle response suppression by hedonic stimuli. Collectively, our results suggest that functional integrity of left dorsolateral and dorsomedial prefrontal cortex is critical for mediating a pleasure-induced down-regulation of avoidance responses which may protect the brain from a depressogenic preponderance of defensive stress. PMID:25752944

  17. Substrate-biasing during plasma-assisted atomic layer deposition to tailor metal-oxide thin film growth

    SciTech Connect

    Profijt, H. B.; Sanden, M. C. M. van de; Kessels, W. M. M.

    2013-01-15

    Two substrate-biasing techniques, i.e., substrate-tuned biasing and RF biasing, have been implemented in a remote plasma configuration, enabling control of the ion energy during plasma-assisted atomic layer deposition (ALD). With both techniques, substrate bias voltages up to -200 V have been reached, which allowed for ion energies up to 272 eV. Besides the bias voltage, the ion energy and the ion flux, also the electron temperature, the electron density, and the optical emission of the plasma have been measured. The effects of substrate biasing during plasma-assisted ALD have been investigated for Al{sub 2}O{sub 3}, Co{sub 3}O{sub 4}, and TiO{sub 2} thin films. The growth per cycle, the mass density, and the crystallinity have been investigated, and it was found that these process and material properties can be tailored using substrate biasing. Additionally, the residual stress in substrates coated with Al{sub 2}O{sub 3} films varied with the substrate bias voltage. The results reported in this article demonstrate that substrate biasing is a promising technique to tailor the material properties of thin films synthesized by plasma-assisted ALD.

  18. Investigation of the interfacial adhesion of the transparent conductive oxide films to large-area flexible polymer substrates using laser-induced thermo-mechanical stresses

    NASA Astrophysics Data System (ADS)

    Park, Jin-Woo; Lee, Seung-Ho; Yang, Chan-Woo

    2013-08-01

    In this study, we investigated the interfacial adhesion strength (σint) of transparent conductive oxide (TCO) coatings on polymer substrates using a nanosecond Nd:YAG pulsed laser. We compared our results with those achieved using conventional testing methods such as bending and fragmentation tests as well as theoretical calculations. In the fragmentation and bending tests, mechanical compressive stress is induced in the film due to mismatches in Poisson's ratio and Young's modulus between the substrate and film. But, the incident laser makes the film under compression due to the mismatch in thermal expansion between the TCO and the polymer substrate. With a pulse incident to the substrate, the TCO rapidly expands by laser-induced instant heating while the transparent polymer does little, which causes the TCO to buckle and delaminate over the critical pulse energy. The critical compressive stress that scales with σint was calculated using simple equations, which agreed well with the results from previous theoretical calculations. Because the films preferentially delaminate at the defects and grain boundaries, this technique also provided useful information regarding the interface microstructures. Moreover, because the laser can scan over large areas, this method is suitable for flexible substrates that are produced by a roll-to-roll process. Nevertheless, the mechanical stress introduced by the bending and fragmentation tests causes the TCO to buckle without interfacial delamination. Hence, the stresses at the buckling disagreed with the results obtained from the laser test and the theoretical calculations.

  19. Modes of heme binding and substrate access for cytochrome P450 CYP74A revealed by crystal structures of allene oxide synthase

    SciTech Connect

    Li, Lenong; Chang, Zhenzhan; Pan, Zhiqiang; Fu, Zheng-Qing; Wang, Xiaoqiang

    2009-01-12

    Cytochrome P450s exist ubiquitously in all organisms and are involved in many biological processes. Allene oxide synthase (AOS) is a P450 enzyme that plays a key role in the biosynthesis of oxylipin jasmonates, which are involved in signal and defense reactions in higher plants. The crystal structures of guayule (Parthenium argentatum) AOS (CYP74A2) and its complex with the substrate analog 13(S)-hydroxyoctadeca-9Z,11E-dienoic acid have been determined. The structures exhibit a classic P450 fold but possess a heme-binding mode with an unusually long heme binding loop and a unique I-helix. The structures also reveal two channels through which substrate and product may access and leave the active site. The entrances are defined by a loop between {beta}3-2 and {beta}3-3. Asn-276 in the substrate binding site may interact with the substrate's hydroperoxy group and play an important role in catalysis, and Lys-282 at the entrance may control substrate access and binding. These studies provide both structural insights into AOS and related P450s and a structural basis to understand the distinct reaction mechanism.

  20. Effects of substrate voltage on noise characteristics and hole lifetime in SOI metal-oxide-semiconductor field-effect transistor photon detector.

    PubMed

    Putranto, Dedy Septono Catur; Priambodo, Purnomo Sidi; Hartanto, Djoko; Du, Wei; Satoh, Hiroaki; Ono, Atsushi; Inokawa, Hiroshi

    2014-09-01

    Low-frequency noise and hole lifetime in silicon-on-insulator (SOI) metal-oxide-semiconductor field-effect transistors (MOSFETs) are analyzed, considering their use in photon detection based on single-hole counting. The noise becomes minimum at around the transition point between front- and back-channel operations when the substrate voltage is varied, and increases largely on both negative and positive sides of the substrate voltage showing peculiar Lorentzian (generation-recombination) noise spectra. Hole lifetime is evaluated by the analysis of drain current histogram at different substrate voltages. It is found that the peaks in the histogram corresponding to the larger number of stored holes become higher as the substrate bias becomes larger. This can be attributed to the prolonged lifetime caused by the higher electric field inside the body of SOI MOSFET. It can be concluded that, once the inversion channel is induced for detection of the photo-generated holes, the small absolute substrate bias is favorable for short lifetime and low noise, leading to high-speed operation. PMID:25321581

  1. Structural, optical and electrical properties studies of ultrasonically deposited tin oxide (SnO2) thin films with different substrate temperatures

    NASA Astrophysics Data System (ADS)

    Rahal, Achour; Benhaoua, Atmane; Jlassi, Mohamed; Benhaoua, Boubaker

    2015-10-01

    Undoped thin films of tin oxide (SnO2) were deposited onto microscopic glass substrates using an ultrasonic spray pyrolysis technique. The thin films were deposited on glass at large scale of temperature ranged in 400-500 °C and stepped by 20 °C. The effect of substrate temperature on structural, electrical and optical properties was studied using X-ray diffraction (XRD), UV-visible spectrophotometer and a conventional four point probe technique. XRD showed that all the films were polycrystalline with major reflex along (1 1 0) plane, manifested with amelioration of grain size from 6.51 to 29.80 nm upon increasing substrate temperature. Lattice constant 'a', 'c', microstrains and dislocation densities were affected by the substrate temperature. Transmittance of about 75% at more than 800 nm for films prepared at 480 °C has been observed. With increasing the substrate temperature the direct band gap energy was averaged in 4.03-4.133 eV. Plasma frequency (ωp) was estimated to be 4 ṡ 1014 Hz and optically estimated free electrons number N leading to predict that, in SnO2 material, the effective density of conduction band states is about 5 ṡ 1019 cm-3. Among all the samples the film that deposited at 480 °C exhibited lowest resistivity of about 9.19 × 10-3 Ω cm.

  2. Fabrication and characterization of nano-HA-45S5 bioglass composite coatings on calcium-phosphate containing micro-arc oxidized CP-Ti substrates

    NASA Astrophysics Data System (ADS)

    Farnoush, Hamidreza; Muhaffel, Faiz; Cimenoglu, Huseyin

    2015-01-01

    In the present study, micro-arc oxidation (MAO) was carried out on commercially pure titanium (CP-Ti) to fabricate porous titanium oxide coatings containing calcium phosphates (CaP) at different applied voltages of 300, 330 and 360 V for 5 min. Subsequently, nano-hydroxyapatite (HA) and HA-45S5 bioglass (BG) composite were effectively coated on micro-arc oxidized substrate by electrophoretic deposition (EPD) at a constant voltage of 30 V for 120 s. The phase, structural agents, microstructure and composition of MAO interlayer and subsequent EPD coatings were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy, respectively. Thermal stability of the as-deposited coatings was analyzed by simultaneous differential scanning calorimetry and thermal gravimetery. The pull-off adhesion tests showed the highest bonding strength was obtained for HA-BG coating on micro-oxidized sample at 360 V. The results of potentiodynamic polarization and impedance spectroscopic measurements in simulated body fluid solution depicted that the combination of MAO treatment at 360 V and EPD of HA-BG composite could effectively increase the corrosion resistance of CP-Ti substrates.

  3. The impact of implantation sequence on the characterization of n-MOSFET's with gate oxide grown on nitrogen-implanted Si substrate

    NASA Astrophysics Data System (ADS)

    Wu, You-Lin

    2002-08-01

    Both of the nitrogen implantation and threshold-voltage adjustment implantation introduce dopant atoms near the SiO 2/Si interface during the fabrication of n-channel metal-oxide-semiconductor field-effect transistor (n-MOSFET's) with gate oxide grown on nitrogen implanted silicon substrate. This work examined the impact of implantation sequence on the characterization of n-MOSFET's with gate oxide grown on nitrogen implanted silicon substrate. It is found that the sequence of nitrogen implantation and boron implantation affects both the electrical characteristics and hot-carrier properties of n-MOSFET's. It is found that no channel mobility degradation, less interface state density, lower subthreshold leakage current and better hot-carrier resistance can be achieved in the n-MOSFET's if the threshold-voltage adjustment implantation is performed after the nitrogen implantation during the gate oxide preparation. However lower channel mobility, higher interface state density, higher subthreshold leakage current and less hot-carrier resistance were observed if the implantation sequence was reversed.

  4. Effect of the chemical termination of conductive diamond substrate on the resistance to carbon monoxide-poisoning during methanol oxidation of platinum particles

    NASA Astrophysics Data System (ADS)

    Spătaru, Tanţa; Osiceanu, Petre; Anastasescu, Mihai; Pătrinoiu, Greta; Munteanu, Cornel; Spătaru, Nicolae; Fujishima, Akira

    2014-09-01

    Boron-doped diamond (BDD) films were annealed in hydrogen or oxygen streams and were further used as substrates for Pt electrochemical deposition. SEM and AFM measurements have shown that, from the point of view of the efficiency of noble metal utilization, a hydrogen-terminated diamond (HT-BDD) support is more convenient because it enables better dispersion and smaller size of the deposited particles. An enhancement of ca. 23% of the electrocatalyst specific surface area was observed for Pt/HT-BDD, compared to the case of Pt deposited at oxygen-terminated diamond (OT-BDD). Nevertheless, it was found that when deposited on oxidized BDD, Pt particles are more resistant to fouling during methanol oxidation. Electrochemical oxidation of adsorbed carbon monoxide was investigated by anodic stripping voltammetry and it was demonstrated that the use of OT-BDD substrate facilitates oxidative desorption of CO from the platinum active sites. This behavior was tentatively ascribed to the high surface concentration of oxygenated carbon species, evidenced by XPS, which may act as oxygen donors and/or could partially weaken Pt-CO bonds, thus enabling easier CO eviction from the electrocatalyst surface.

  5. Room-temperature single-electron memory made by pulse-mode atomic force microscopy nano oxidation process on atomically flat α-alumina substrate

    NASA Astrophysics Data System (ADS)

    Matsumoto, Kazuhiko; Gotoh, Yoshitaka; Maeda, Tatsuro; Dagata, John A.; Harris, James S.

    2000-01-01

    A single-electron memory was fabricated using the improved pulse-mode atomic force microscopy nano oxidation process which oxidized the surface of the thin titanium (Ti) metal on the atomically flat α-alumina (α-Al2O3) substrate and formed the narrow oxidized titanium (TiOx) line that works as a tunnel junction for the device. This single-electron memory consists of the multitunnel junction and a memory capacitance. The single-electron transistor, which works as an electrometer, was connected to the memory node of the single-electron memory to detect the potential change of the memory node by the injection of the individual electrons. The fabricated single-electron memory showed the hysteresis loop even at room temperature by the return trip of the memory bias when starting from 0 to 10 V and again coming back to 0 V. About 25 electrons were stored at the memory node.

  6. Interaction of hepatic microsomal epoxide hydrolase derived from a recombinant baculovirus expression system with an azarene oxide and an aziridine substrate analogue.

    PubMed

    Lacourciere, G M; Vakharia, V N; Tan, C P; Morris, D I; Edwards, G H; Moos, M; Armstrong, R N

    1993-03-16

    A recombinant baculovirus (vEHX) encoding rat hepatic microsomal epoxide hydrolase has been constructed. Infection of Spodoptera frugiperda (Sf9) cells with the recombinant virus results in the expression of the enzyme at a level estimated to be between 5% and 10% of the cellular protein. The enzyme, which can be purified in 15% yield by a simple three-step procedure involving detergent extraction, DEAE-cellulose chromatography, and removal of the detergent on hydroxylapatite, has physical and kinetic properties very close to those of the enzyme obtained from rat liver microsomes. The interaction of the enzyme with two nitrogen-containing analogues of the substrate phenanthrene 9,10-oxide (1) was investigated in order to delineate the contributions of the oxirane group and the hydrophobic surface of the substrate to substrate recognition. The enzyme exhibits altered kinetic properties toward 1,10-phenanthroline 5,6-oxide (2) in which the biphenyl group of 1 is replaced with a bipyridyl group, suggesting that hydrophobic interaction between the complementary surfaces of the substrate and active site has an influence on catalysis. The conjugate acid of the aziridine analogue of 1, phenanthrene 9,10-imine (3), in which the oxirane oxygen is replaced with NH, has a pKa of 6.1, which allows the characterization of both the neutral and protonated aziridine (3H+) as substrate analogues for the enzyme. The pH dependence of the solvolysis reveals that 3H+ rearranges to a 65/35 mixture of 9-aminophenanthrene and 9-amino-10-hydroxy-9,10-dihydrophenanthrene 10(3)-fold faster than does 3. The neutral aziridine is a competitive inhibitor (Ki = 26 microM) of the enzyme at pH 8.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8383521

  7. Investigation into the role of sodium chloride deposited on oxide and metal substrates in the initiation of hot corrosion

    NASA Technical Reports Server (NTRS)

    Birks, N.

    1983-01-01

    Sodium chloride is deposited on the surface of alumina substrates and exposed to air containing 1% SO2 at temperatures between 500 C and 700 C. In all cases the sodium chloride was converted to sodium sulfate. The volatilization of sodium chloride from the original salt particles was responsible for the development of a uniform coating of sodium sulfate on the alumina substrate. At temperatures above 625 C, a liquid NaCl-Na2SO4 autectic was formed on the substrate. The mechanisms for these reactions are given. One of the main roles of NaCl in low temperature hot corrosion lies in enabling a corrosive liquid to form.

  8. Dopamine interferes with appetitive long-term memory formation in honey bees.

    PubMed

    Klappenbach, Martín; Kaczer, Laura; Locatelli, Fernando

    2013-11-01

    Studies in vertebrates and invertebrates have proved the instructive role that different biogenic amines play in the neural representation of rewards and punishments during associative learning. Results from diverse arthropods and using different learning paradigms initially agreed that dopamine (DA) is needed for aversive learning and octopamine (OA) is needed for appetitive learning. However, the notion that both amines constitute separate pathways for appetitive and aversive learning is changing. Here, we asked whether DA, so far only involved in aversive memory formation in honey bees, does also modulate appetitive memory. Using the well characterized appetitive olfactory conditioning of the proboscis extension reflex (PER), we show that DA impairs appetitive memory consolidation. In addition, we found that blocking DA receptors enhances appetitive memory. These results are consistent with the view that aversive and appetitive components interact during learning and memory formation to ensure adaptive behavior. PMID:24076013

  9. 3D silver nanoparticles decorated zinc oxide/silicon heterostructured nanomace arrays as high-performance surface-enhanced Raman scattering substrates.

    PubMed

    Huang, Jian; Chen, Feng; Zhang, Qing; Zhan, Yonghua; Ma, Dayan; Xu, Kewei; Zhao, Yongxi

    2015-03-18

    Three-dimensional (3D) hierarchical nanostructures have been considered as one of the most promising surface-enhanced Raman spectroscopy (SERS) substrates because of the ordered arrangement of high-density hotspots along the third dimension direction. Herein, we reported a unique 3D nanostructure for SERS detection based on silver nanoparticles (AgNPs) decorated zinc oxide/silicon (ZnO/Si) heterostructured nanomace arrays. They were prepared by two steps: (1) Si nanoneedles were grafted onto ZnO nanorod arrays via a catalyst-assisted vapor-liquid-solid (VLS) growth mechanism. (2) AgNPs were rapidly immobilized on the surface of nanomaces by a facile galvanic displacement reaction. The fabricated substrates were employed to detect rhodamine 6G (R6G) with a detection limit down to 10(-16) M, and exhibited a high-enhanced performance (enhancement factor (EF) as high as 8.7 × 10(7)). To illustrate the potential value of the prepared substrates, the different concentrations of melamine aqueous solution (from 10(-4) to 10(-10) M) were detected, and a quantitative relationship between the SERS spectrum intensity and the melamine concentration had been established. In addition, the measure of melamine residual in pure milk was carried out successfully, and the results indicated that the prepared 3D nanomace substrates had great potential in food inspection, environment protection, and a few other technologically important fields. PMID:25731067

  10. Integrated biological and advanced oxidation based treatment of hexamine bearing wastewater: Effect of cow-dung as a co-substrate.

    PubMed

    Gupta, Mandeep Kumar; Mittal, Atul K

    2016-05-01

    This work examines the treatment of hexamethylenetetramine (HMT) bearing effluent from N, N-dinitroso pentamethylene tetra-mine producing industrial plants in India. Chemical treatment using Fenton's reagent and aerobic treatment using batch reactors with co-substrate were investigated. Aerobic batch reactors integrated with advanced oxidation process of Fenton's reagent provides effective treatment of HMT effluents. Influence of Fenton's reagent dose reaction/contact and effect of varying co-substrate with effluent initial concentration was observed. Higher dose 100 mL of Fenton's reagent with higher reaction time 20 h resulted better degradation (34.88%) of wastewater. HMT hydrolyzes in acidic environment to ammonia and formaldehyde. Formaldehyde under normal conditions is toxic for biological treatment processes. When hydrolysis and acidification in the reactors are accompanied by low pH, aerobic batch reactors with use of co-substrates glucose, sucrose, and cow-dung extract separately in different proportion to wastewater ranging from 0.67 to 4.00, degraded wastewater effectively. Higher proportion of co-substrate to wastewater resulted better degradation. The relationships between nitrate, pH, turbidity and COD are discussed. PMID:26855186

  11. Silicon oxide barrier films deposited on PET foils in pulsed plasmas: influence of substrate bias on deposition process and film properties

    NASA Astrophysics Data System (ADS)

    Steves, S.; Ozkaya, B.; Liu, C.-N.; Ozcan, O.; Bibinov, N.; Grundmeier, G.; Awakowicz, P.

    2013-02-01

    A widely used plastic for packaging, polyethylene terephtalate (PET) offers limited barrier properties against gas permeation. For many applications of PET (from food packaging to micro electronics) improved barrier properties are essential. A silicon oxide barrier coating of PET foils is applied by means of a pulsed microwave driven low-pressure plasma. While the adjustment of the microwave power allows for a control of the ion production during the plasma pulse, a substrate bias controls the energy of ions impinging on the substrate. Detailed analysis of deposited films applying oxygen permeation measurements, x-ray photoelectron spectroscopy and atomic force microscopy are correlated with results from plasma diagnostics describing the deposition process. The influence of a change in process parameters such as gas mixture and substrate bias on the gas temperature, electron density, mean electron energy, ion energy and the atomic oxygen density is studied. An additional substrate bias results in an increase in atomic oxygen density up to a factor of 6, although plasma parameter such as electron density of ne = 3.8 ± 0.8 × 1017 m-3 and electron temperature of kBTe = 1.7 ± 0.1 eV are unmodified. It is shown that atomic oxygen densities measured during deposition process higher than nO = 1.8 × 1021 m-3 yield in barrier films with a barrier improvement factor up to 150. Good barrier films are highly cross-linked and show a smooth morphology.

  12. Enzymological and Structural Studies of the Mechanism of Promiscuous Substrate Recognition by the Oxidative DNA Repair Enzyme AlkB

    SciTech Connect

    Yu, B.; Hunt, J

    2009-01-01

    Promiscuous substrate recognition, the ability to catalyze transformations of chemically diverse compounds, is an evolutionarily advantageous, but poorly understood phenomenon. The promiscuity of DNA repair enzymes is particularly important, because it enables diverse kinds of damage to different nucleotide bases to be repaired in a metabolically parsimonious manner. We present enzymological and crystallographic studies of the mechanisms underlying promiscuous substrate recognition by Escherichia coli AlkB, a DNA repair enzyme that removes methyl adducts and some larger alkylation lesions from endocyclic positions on purine and pyrimidine bases. In vitro Michaelis-Menten analyses on a series of alkylated bases show high activity in repairing N1-methyladenine (m1A) and N3-methylcytosine (m3C), comparatively low activity in repairing 1,N6-ethenoadenine, and no detectable activity in repairing N1-methylguanine or N3-methylthymine. AlkB has a substantially higher kcat and Km for m3C compared with m1A. Therefore, the enzyme maintains similar net activity on the chemically distinct substrates by increasing the turnover rate of the substrate with nominally lower affinity. Cocrystal structures provide insight into the structural basis of this 'kcat/Km compensation,' which makes a significant contribution to promiscuous substrate recognition by AlkB. In analyzing a large ensemble of crystal structures solved in the course of these studies, we observed 2 discrete global conformations of AlkB differing in the accessibility of a tunnel hypothesized to control diffusion of the O2 substrate into the active site. Steric interactions between a series of protein loops control this conformational transition and present a plausible mechanism for preventing O2 binding before nucleotide substrate binding.

  13. Effects of the once-daily GLP-1 analog liraglutide on gastric emptying, glycemic parameters, appetite and energy metabolism in obese, non-diabetic adults

    PubMed Central

    van Can, J; Sloth, B; Jensen, C B; Flint, A; Blaak, E E; Saris, W H M

    2014-01-01

    Introduction: Mechanisms for liraglutide-induced weight loss are poorly understood. Objective: We investigated the effects of liraglutide on gastric emptying, glycemic parameters, appetite and energy metabolism in obese non-diabetic individuals. Design: Participants (N=49, 18–75 years, body mass index: 30–40 kg m−2) were randomized to two of three treatments: liraglutide 1.8 mg, 3.0 mg, or placebo in a double-blind, incomplete crossover trial. After 5 weeks, 24-h energy expenditure (EE) and substrate oxidation were measured in a respiratory chamber. Gastric emptying (acetaminophen absorption method), glycemic parameters and appetite were assessed during a 5-h meal test. Ad libitum energy intake during a subsequent lunch was also assessed. Results: Five-hour gastric emptying (AUC0–300 min) was found to be equivalent for liraglutide 1.8 versus 3.0 mg (primary end point), and for both liraglutide doses versus placebo, as 90% confidence intervals for the estimated treatment ratios were contained within the prespecified interval (0.80–1.25). However, 1-h gastric emptying was 23% lower than placebo with liraglutide 3.0 mg (P=0.007), and a nonsignificant 13% lower than placebo with liraglutide 1.8 mg (P=0.14). Both liraglutide doses similarly reduced fasting glucose (0.5–0.6 mmol l−1 versus placebo, P<0.0001), glucose Cmax and 1-h AUC versus placebo; only liraglutide 3.0 mg reduced iAUC0–300 min (by ∼26% versus placebo, P=0.02). Glucagon iAUC0–300 min decreased by ∼30%, and iAUC0–60 min for insulin and C-peptide was ∼20% lower with both liraglutide doses versus placebo. Liraglutide doses similarly increased mean postprandial satiety and fullness ratings, reduced hunger and prospective food consumption and decreased ad libitum energy intake by ∼16%. Liraglutide-associated reductions in EE were partly explained by a decrease in body weight. A relative shift toward increased fat and reduced carbohydrate oxidation was

  14. Prolonged fasting identifies heat shock protein 10 as a Sirtuin 3 substrate: elucidating a new mechanism linking mitochondrial protein acetylation to fatty acid oxidation enzyme folding and function.

    PubMed

    Lu, Zhongping; Chen, Yong; Aponte, Angel M; Battaglia, Valentina; Gucek, Marjan; Sack, Michael N

    2015-01-23

    Although Sirtuin 3 (SIRT3), a mitochondrially enriched deacetylase and activator of fat oxidation, is down-regulated in response to high fat feeding, the rate of fatty acid oxidation and mitochondrial protein acetylation are invariably enhanced in this dietary milieu. These paradoxical data implicate that additional acetylation modification-dependent levels of regulation may be operational under nutrient excess conditions. Because the heat shock protein (Hsp) Hsp10-Hsp60 chaperone complex mediates folding of the fatty acid oxidation enzyme medium-chain acyl-CoA dehydrogenase, we tested whether acetylation-dependent mitochondrial protein folding contributes to this regulatory discrepancy. We demonstrate that Hsp10 is a functional SIRT3 substrate and that, in response to prolonged fasting, SIRT3 levels modulate mitochondrial protein folding. Acetyl mutagenesis of Hsp10 lysine 56 alters Hsp10-Hsp60 binding, conformation, and protein folding. Consistent with Hsp10-Hsp60 regulation of fatty acid oxidation enzyme integrity, medium-chain acyl-CoA dehydrogenase activity and fat oxidation are elevated by Hsp10 acetylation. These data identify acetyl modification of Hsp10 as a nutrient-sensing regulatory node controlling mitochondrial protein folding and metabolic function. PMID:25505263

  15. Alumina nanoparticle/polymer nanocomposite dielectric for flexible amorphous indium-gallium-zinc oxide thin film transistors on plastic substrate with superior stability

    SciTech Connect

    Lai, Hsin-Cheng; Pei, Zingway; Jian, Jyun-Ruri; Tzeng, Bo-Jie

    2014-07-21

    In this study, the Al{sub 2}O{sub 3} nanoparticles were incorporated into polymer as a nono-composite dielectric for used in a flexible amorphous Indium-Gallium-Zinc Oxide (a-IGZO) thin-film transistor (TFT) on a polyethylene naphthalate substrate by solution process. The process temperature was well below 100 °C. The a-IGZO TFT exhibit a mobility of 5.13 cm{sup 2}/V s on the flexible substrate. After bending at a radius of 4 mm (strain = 1.56%) for more than 100 times, the performance of this a-IGZO TFT was nearly unchanged. In addition, the electrical characteristics are less altered after positive gate bias stress at 10 V for 1500 s. Thus, this technology is suitable for use in flexible displays.

  16. Evidence of native oxides on the capping and substrate of Permalloy gratings by magneto-optical spectroscopy in the zeroth- and first-diffraction orders

    SciTech Connect

    Antos, Roman; Mistrik, Jan; Yamaguchi, Tomuo; Visnovsky, Stefan; Demokritov, Sergej O.; Hillebrands, Burkard

    2005-06-06

    Magneto-optical Kerr effect (MOKE) spectroscopy in the zeroth- and first-diffraction orders at polar magnetization is applied to Permalloy wire gratings deposited on Si substrates and protected by Cr capping. The experimental MOKE data are compared with data simulated using the local modes method. The extensive simulations of the MOKE spectroscopic parameters exhibit significant sensitivity to t(Cr{sub 2}O{sub 3}) and t(SiO{sub 2}), the thicknesses of native oxide layers developed on the capping and the substrate, respectively. The approach may be useful for monitoring the basic micromagnetic properties of small elements with nanometer-scale resolution, as well as for monitoring the deposition processes and aging of magnetic nanostructures in magnetic recording and magnetic random access memory technologies.

  17. In situ electro-mechanical experiments and mechanics modeling of tensile cracking in indium tin oxide thin films on polyimide substrates

    NASA Astrophysics Data System (ADS)

    Peng, Cheng; Jia, Zheng; Bianculli, Dan; Li, Teng; Lou, Jun

    2011-05-01

    Indium tin oxide (ITO) thin films supported by polymer substrates have been widely used as transparent electrodes/interconnects in flexible electronics. Understanding the electro-mechanical behaviors of such material system is crucial for reliable operation of flexible devices under large deformation. In this paper, we performed in situ mechanical and electrical tests of ITO thin films with two different thicknesses (200 and 80 nm) deposited on polyimide substrates inside a scanning electron microscope. The crack initiation and propagation, crack density evolution and the corresponding electrical resistance variation were systematically investigated. It was found that cracks initiated at a higher tensile strain level and saturated with a higher density in thinner ITO films. Integrated with a coherently formulated mechanics model, the cohesive toughness and fracture strength of ITO thin films and the ITO/polyimide interfacial toughness were quantitatively determined. The experimentally observed thickness dependence of the saturated crack density in ITO thin films was also quantitatively verified by the model.

  18. Structural, optical, and electrical properties of Cu2O nanocubes grown on indium-tin-oxide-coated glass substrates by using seed-layer-free electrochemical deposition method

    NASA Astrophysics Data System (ADS)

    No, Young Soo; Oh, Do Hyon; Kim, Su Yeon; Yoo, Keon-Ho; Kim, Tae Whan

    2012-07-01

    Electrochemical deposition was employed to fabricate Cu2O nanocubes on indium-tin-oxide (ITO)-coated glass substrates at 75 °C without using any template, catalyst, or seed layer. Scanning electron microscopy images showed that the Cu2O nanocubes with a nanoscale size were uniformly formed on ITO-coated glass substrates. X-ray patterns of the Cu2O nanocubes exhibited the dominant peaks corresponding to the Cu2O cubic structures. The current-voltage curves of an Au/n-type Al-doped ZnO/p-type Cu2O nanocube/ITO device clearly showed current rectifying behavior with a turn-on voltage of 3.6 V.

  19. Amorphous Indium Gallium Zinc Oxide Thin-Film Transistors with a Low-Temperature Polymeric Gate Dielectric on a Flexible Substrate

    NASA Astrophysics Data System (ADS)

    Hyung, Gun Woo; Park, Jaehoon; Wang, Jian-Xun; Lee, Ho Won; Li, Zhao-Hui; Koo, Ja-Ryong; Kwon, Sang Jik; Cho, Eou-Sik; Kim, Woo Young; Kim, Young Kwan

    2013-07-01

    Amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) with a solution-processed polymeric gate dielectric of cross-linked poly(4-vinylphenol) (c-PVP) film were fabricated on a poly(ethylene terephthalate) (PET) substrate on which an a-IGZO film, as the active channel layer, was deposited by radio frequency (RF) sputtering. The entire TFT fabrication process was carried out at a temperature below 110 °C. The device exhibited an on/off ratio of 1.5×106 and a high field-effect mobility of 10.2 cm2 V-1 s-1, which is, to our knowledge, the best result ever achieved among a-IGZO TFTs with polymeric gate dielectrics on a plastic substrate.

  20. An approach to the development of drugs for appetite disorders.

    PubMed

    Morley, J E

    1989-01-01

    This review covers some modern concepts in the development of drugs to treat appetite disorders. Specific attention is paid to the peripheral satiety system and the role of gastrointestinal peptides such as cholecystokinin in the pathogenesis of satiety. Alterations in neuropeptide Y and/or peptide YY are suggested to play a role in the pathophysiology of bulimia. Corticotropin-releasing factor is a putative candidate peptide involved in anorexia nervosa. The serotonin reuptake inhibitors fenfluramine and fluoxetene decrease weight in obese subjects. Endogenous opioids modulate the choice of palatable foods. Anorexia in the old appears to be related to a decrease in opioid feeding drive and an excess of the satiety action of cholecystokinin. Other agents involved in weight regulation include those which alter gastric emptying, increase thermogenesis, or modulate fat cell metabolism. It should be stressed that many neurotransmitters that modulate appetite also alter other behaviors, increasing their propensity to produce side effects. PMID:2573002

  1. Substrate Specificity of MarP, a Periplasmic Protease Required for Resistance to Acid and Oxidative Stress in Mycobacterium tuberculosis*

    PubMed Central

    Small, Jennifer L.; O'Donoghue, Anthony J.; Boritsch, Eva C.; Tsodikov, Oleg V.; Knudsen, Giselle M.; Vandal, Omar; Craik, Charles S.; Ehrt, Sabine

    2013-01-01

    The transmembrane serine protease MarP is important for pH homeostasis in Mycobacterium tuberculosis (Mtb). Previous structural studies revealed that MarP contains a chymotrypsin fold and a disulfide bond that stabilizes the protease active site in the substrate-bound conformation. Here, we determined that MarP is located in the Mtb periplasm and showed that this localization is essential for function. Using the recombinant protease domain of MarP, we identified its substrate specificity using two independent assays: positional-scanning synthetic combinatorial library profiling and multiplex substrate profiling by mass spectrometry. These methods revealed that MarP prefers bulky residues at P4, tryptophan or leucine at P2, arginine or hydrophobic residues at P1, and alanine or asparagine at P1′. Guided by these data, we designed fluorogenic peptide substrates and characterized the kinetic properties of MarP. Finally, we tested the impact of mutating MarP cysteine residues on the peptidolytic activity of recombinant MarP and its ability to complement phenotypes of Mtb ΔMarP. Taken together, our studies provide insight into the enzymatic properties of MarP, its substrate preference, and the importance of its transmembrane helices and disulfide bond. PMID:23504313

  2. Hypothalamic opioid-melanocortin appetitive balance and addictive craving.

    PubMed

    Reece, Albert Stuart

    2011-01-01

    Whilst the parallels between drug and food craving are receiving increasing attention, the recently elucidated complex physiology of the hypothalamic appetite regulatory centres has been largely overlooked in the efforts to understand drug craving which is one of the most refractory and problematic aspects of drug and behavioural addictions. Important conceptual gains could be made by researchers from both appetite and addiction neuroscience if they were to have an improved understanding of each others' disciplines. It is well known in addiction medicine that the use of many substances is elevated in opiate dependency. There is voluminous evidence of very high rates of drug use in opiate agonist maintained patients, and the real possibility exists that opiate agonist therapy therefore increases drug craving. Conversely, opiate antagonist therapy with naloxone or naltrexone has been shown to reduce most chemical and behavioural addictions, and naltrexone is now being developed together with bupropion as the anti-obesity drug "Contrave". Hypothalamic melanocortins, particularly α-MSH, are known to constitute the main brake to consumptive behaviour of food. There is a well described antagonism between melanocortins and opioids at many loci including the hypothalamus. Administration of exogenous opiates is known to both suppress α-MSH and to stimulate hedonic food consumption. Opiate maintenance programs are associated with weight gain. As monoamines, opioids and cannabinoids are known to be involved in appetite regulation, and as endorphin opioids are known to be perturbed in other addictions, further exploration of the hypothalamic appetite regulatory centre would appear to be an obvious, albeit presently largely overlooked, locus in which to study drug and other craving mechanisms. PMID:20926200

  3. Altered motivation masks appetitive learning potential of obese mice

    PubMed Central

    Harb, Mazen R.; Almeida, Osborne F. X.

    2014-01-01

    Eating depends strongly on learning processes which, in turn, depend on motivation. Conditioned learning, where individuals associate environmental cues with receipt of a reward, forms an important part of hedonic mechanisms; the latter contribute to the development of human overweight and obesity by driving excessive eating in what may become a vicious cycle. Although mice are commonly used to explore the regulation of human appetite, it is not known whether their conditioned learning of food rewards varies as a function of body mass. To address this, groups of adult male mice of differing body weights were tested two appetitive conditioning paradigms (pavlovian and operant) as well as in food retrieval and hedonic preference tests in an attempt to dissect the respective roles of learning/motivation and energy state in the regulation of feeding behavior. We found that (i) the rate of pavlovian conditioning to an appetitive reward develops as an inverse function of body weight; (ii) higher body weight associates with increased latency to collect food reward; and (iii) mice with lower body weights are more motivated to work for a food reward, as compared to animals with higher body weights. Interestingly, as compared to controls, overweight and obese mice consumed smaller amounts of palatable foods (isocaloric milk or sucrose, in either the presence or absence of their respective maintenance diets: standard, low fat-high carbohydrate or high fat-high carbohydrate). Notably, however, all groups adjusted their consumption of the different food types, such that their body weight-corrected daily intake of calories remained constant. Thus, overeating in mice does not reflect a reward deficiency syndrome and, in contrast to humans, mice regulate their caloric intake according to metabolic status rather than to the hedonic properties of a particular food. Together, these observations demonstrate that excess weight masks the capacity for appetitive learning in the mouse

  4. Moderate-intensity exercise affects perceived hunger and fullness but not appetite-related hormones in late pregnancy.

    PubMed

    Guelfi, Kym J; Halse, Rhiannon E

    2013-11-01

    The effect of exercise on appetite and appetite-related hormones during pregnancy is not known. This study found that 30 min of moderate-intensity stationary cycling transiently attenuated hunger and increased fullness in late gestational women (n = 12). Exercise did not affect perceived appetite or appetite-related hormones in response to subsequent caloric consumption. These observations suggest that appetite responses do not intrinsically compensate for the additional energy expenditure induced by exercise, at least in the short term. PMID:24053524

  5. Modeling Geometric Arrangements of TiO2-Based Catalyst Substrates and Isotropic Light Sources to Enhance the Efficiency of a Photocatalystic Oxidation (PCO) Reactor

    NASA Technical Reports Server (NTRS)

    Richards, Jeffrey T.; Levine, Lanfang H.; Husk, Geoffrey K.

    2011-01-01

    The closed confined environments of the ISS, as well as in future spacecraft for exploration beyond LEO, provide many challenges to crew health. One such challenge is the availability of a robust, energy efficient, and re-generable air revitalization system that controls trace volatile organic contaminants (VOCs) to levels below a specified spacecraft maximum allowable concentration (SMAC). Photocatalytic oxidation (PCO), which is capable of mineralizing VOCs at room temperature and of accommodating a high volumetric flow, is being evaluated as an alternative trace contaminant control technology. In an architecture of a combined air and water management system, placing a PCO unit before a condensing heat exchanger for humidity control will greatly reduce the organic load into the humidity condensate loop ofthe water processing assembly (WPA) thereby enhancing the life cycle economics ofthe WPA. This targeted application dictates a single pass efficiency of greater than 90% for polar VOCs. Although this target was met in laboratory bench-scaled reactors, no commercial or SBIR-developed prototype PCO units examined to date have achieved this goal. Furthermore, the formation of partial oxidation products (e.g., acetaldehyde) was not eliminated. It is known that single pass efficiency and partial oxidation are strongly dependent upon the contact time and catalyst illumination, hence the requirement for an efficient reactor design. The objective of this study is to maximize the apparent contact time and illuminated catalyst surface area at a given reactor volume and volumetric flow. In this study, a Ti02-based photocatalyst is assumed to be immobilized on porous substrate panels and illumination derived from linear isotropic light sources. Mathematical modeling using computational fluid dynamics (CFD) analyses were performed to investigate the effect of: 1) the geometry and configuration of catalyst-coated substrate panels, 2) porosity of the supporting substrate, and 3

  6. Appetite regulation in Schizothorax prenanti by three CART genes.

    PubMed

    Yuan, Dengyue; Wei, Rongbin; Wang, Tao; Wu, Yuanbing; Lin, Fangjun; Chen, Hu; Liu, Ju; Gao, Yundi; Zhou, Chaowei; Chen, Defang; Li, Zhiqiong

    2015-12-01

    In recent years, cocaine- and amphetamine-regulated transcript (CART) has received much attention as mediators of appetite regulation in mammals. However, the involvement of CART in the feeding behavior of teleosts has not been well understood. In this study, three distinct CARTs were cloned from the Schizothorax prenanti (S. prenanti). Real-time quantitative PCR were applied to characterize the tissue distribution and appetite regulatory effects of CARTs in S. prenanti. The S. prenanti CART-1, CART-2 and CART-3 full-length cDNA sequences were 597 bp, 694 bp and 749 bp in length, encoding the peptides of 125, 120 and 104 amino acid residues, respectively. All the S. prenanti CARTs consisted of three exons and two introns. Tissue distribution analysis showed that the high mRNA levels of S. prenanti CART-1 were observed in the telencephalon and eye, followed by the hypothalamus, myelencephalon, and mesencephalon. The S. prenanti CART-2 mRNA was mainly found in the mesencephalon, hypothalamus, telencephalon and myelencephalon. The S. prenanti CART-3 mRNA was widely distributed among the tissues, with the high levels in the hypothalamus and foregut. In the periprandial experiment, all three CARTs mRNA expressions in the hypothalamus were highly elevated after a meal, suggesting that CARTs are postprandial satiety signals. In the fasting experiment, all three CARTs mRNA expressions decreased after fasting and increased after refeeding, suggesting that CARTs might be involved in regulation of appetite in the S. prenanti. PMID:26316039

  7. Appetite and body weight regulation after bariatric surgery

    PubMed Central

    Münzberg, Heike; Laque, Amanda; Yu, Sangho; Rezai-Zadeh, Kavon; Berthoud, Hans-Rudolf

    2016-01-01

    Bariatric surgery continues to be remarkably efficient in treating obesity and T2DM and a debate has started whether it should remain the last resort only or also be used for the prevention of metabolic diseases. Intense research efforts in humans and rodent models are underway to identify the critical mechanisms underlying the beneficial effects with a view towards non-surgical treatment options. This non-systematic review summarizes and interprets some of this literature, with an emphasis on changes in the controls of appetite. Contrary to earlier views, surgery-induced reduction of energy intake and subsequent weight loss appear to be the main drivers for rapid improvements of glycemic control. The mechanisms responsible for suppression of appetite, particularly in the face of the large weight loss, are not well understood. Although a number of changes in food choice, taste functions, hedonic evaluation, motivation, and self-control have been documented in both humans and rodents after surgery, their importance and relative contribution to diminished appetite has not yet been demonstrated. Furthermore, none of the major candidate mechanisms postulated in mediating surgery induced changes from the gut and other organs to the brain, such as gut hormones and sensory neuronal pathways, have been confirmed yet. Future research efforts should focus on interventional rather than descriptive approaches in both humans and rodent models. PMID:25614206

  8. Highest transmittance and high-mobility amorphous indium gallium zinc oxide films on flexible substrate by room-temperature deposition and post-deposition anneals

    NASA Astrophysics Data System (ADS)

    Gadre, Mandar J.; Alford, T. L.

    2011-08-01

    Amorphous indium gallium zinc oxide (a-IGZO) thin films of the highest transmittance reported in literature were initially deposited onto flexible polymer substrates at room temperature. The films were annealed in vacuum, air, and oxygen to enhance their electrical and optical performances. Electrical and optical characterizations were done before and after anneals. A partial reversal of the degradation in electrical properties upon annealing in oxygen was achieved by subjecting the films to subsequent vacuum anneals. A model was developed based on film texture and structural defects which showed close agreement between the measured and calculated carrier mobility values at low carrier concentrations (2-6 × 1019 cm-3).

  9. Osteoconductivity and Hydrophilicity of TiO2 Coatings on Ti Substrates Prepared by Different Oxidizing Processes

    PubMed Central

    Yamamoto, Dai; Kawai, Ikki; Kuroda, Kensuke; Ichino, Ryoichi; Okido, Masazumi; Seki, Azusa

    2012-01-01

    Various techniques for forming TiO2 coatings on Ti have been investigated for the improvement of the osteoconductivity of Ti implants. However, it is not clear how the oxidizing process affects this osteoconductivity. In this study, TiO2 coatings were prepared using the following three processes: anodizing in 0.1 M H3PO4 or 0.1 M NaOH aqueous solution; thermal oxidation at 673 K for 2 h in air; and a two-step process of anodizing followed by thermal oxidation. The oxide coatings were evaluated using SEM, XRD, and XPS. The water contact angle on the TiO2 coatings was measured as a surface property. The osteoconductivity of these samples was evaluated by measuring the contact ratio of formed hard tissue on the implanted samples (defined as the RB-I value) after 14 d implantation in rats' tibias. Anatase was formed by anodizing and rutile by thermal oxidation, but the difference in the TiO2 crystal structure did not influence the osteoconductivity. Anodized TiO2 coatings were hydrophilic, but thermally oxidized TiO2 coatings were less hydrophilic than anodized TiO2 coatings because they lacked in surface OH groups. The TiO2 coating process using anodizing without thermal oxidation gave effective improvement of the osteoconductivity of Ti samples. PMID:23316128

  10. Template preparation of Pt-Ru and Pt nanowire array electrodes on a Ti/Si substrate for methanol electro-oxidation

    NASA Astrophysics Data System (ADS)

    Zhao, Guang-Yu; Xu, Cai-Ling; Guo, Dao-Jun; Li, Hua; Li, Hu-Lin

    Pt and Pt-Ru nanowire array electrodes were obtained by dc (direct current) electrodeposition of Pt and Ru into the pores of an anodic aluminum oxide (AAO) template on a Ti/Si substrate. Transmission electron microscope (TEM) examination showed all the nanowires had a uniform diameter of about 30 nm. The brush shaped Pt and Pt-Ru nanowire array electrodes could be seen clearly by scanning electron microscope. Pt and Pt-Ru nanowire array electrodes gave the X-ray diffraction pattern of a face-centered cubic (fcc) crystal structure. The electro-oxidation of methanol on these electrodes was investigated at room temperature using cyclic voltammetry. The results demonstrated that the alloy nanowire array electrode was catalytically more active than a pure platinum nanowire array electrode and the Pt-Ru nanowire array electrode may have good potential for applications in portable fuel cell power sources.

  11. Drawing Circuits with Carbon Nanotubes: Scratch-Induced Graphoepitaxial Growth of Carbon Nanotubes on Amorphous Silicon Oxide Substrates

    PubMed Central

    Choi, Won Jin; Chung, Yoon Jang; Kim, Yun Ho; Han, Jeongho; Lee, Young-Kook; Kong, Ki-jeong; Chang, Hyunju; Lee, Young Kuk; Kim, Byoung Gak; Lee, Jeong-O

    2014-01-01

    Controlling the orientations of nanomaterials on arbitrary substrates is crucial for the development of practical applications based on such materials. The aligned epitaxial growth of single-walled carbon nanotubes (SWNTs) on specific crystallographic planes in single crystalline sapphire or quartz has been demonstrated; however, these substrates are unsuitable for large scale electronic device applications and tend to be quite expensive. Here, we report a scalable method based on graphoepitaxy for the aligned growth of SWNTs on conventional SiO2/Si substrates. The “scratches” generated by polishing were found to feature altered atomic organizations that are similar to the atomic alignments found in vicinal crystalline substrates. The linear and circular scratch lines could promote the oriented growth of SWNTs through the chemical interactions between the C atoms in SWNT and the Si adatoms in the scratches. The method presented has the potential to be used to prepare complex geometrical patterns of SWNTs by ‘drawing' circuits using SWNTs without the need for state-of-the-art equipment or complicated lithographic processes. PMID:24924480

  12. Electrochemical Response of Biomolecules on Carbon Substrates: Comparison between Oxidized HOPG and O-Terminated Boron-Doped CVD Diamond

    NASA Astrophysics Data System (ADS)

    Baier, Claudia; Sternschulte, Hadwig; Denisenko, Andrej; Schlichtiger, Alice; Stimming, Ulrich

    In this work, two types of electroactive proteins, namely azurin and ferrocene-labeled papain, were adsorbed on differently oxidized diamond and investigated by cyclic voltammetry. A comparison was made with oxidized highly oriented pyrolytic graphite (HOPG). A direct electron transfer to the biomolecules was confirmed for all oxidized carbon electrodes. A strong influence of the oxygen termination process of diamond on the charge transfer through the interface has been observed. This effect has been attributed to different defects and electronic states at the interface, as confirmed by capacitance-voltage measurements in electrolyte, electrical characterisation and X-ray photoemission spectroscopy (XPS). Wet chemical oxidized diamond was proved to be the most effective electrode material for biomolecule anchoring with an electron transfer rate higher by factor of three than that of HOPG.

  13. Outcoupling-Enhanced Flexible Organic Light-Emitting Diodes on Ameliorated Plastic Substrate with Built-in Indium-Tin-Oxide-Free Transparent Electrode.

    PubMed

    Xiang, Heng-Yang; Li, Yan-Qing; Zhou, Lei; Xie, Hao-Jun; Li, Chi; Ou, Qing-Dong; Chen, Lin-Sen; Lee, Chun-Sing; Lee, Shuit-Tong; Tang, Jian-Xin

    2015-07-28

    Enhancing light outcoupling in flexible organic light-emitting diodes (FOLEDs) is an important task for increasing their efficiencies for display and lighting applications. Here, a strategy for an angularly and spectrally independent boost in light outcoupling of FOLEDs is demonstrated by using plastic substrates with a low refractive index, consisting of a bioinspired optical coupling layer and a transparent conductive electrode composed of a silver network. The good transmittance to full-color emission (>94% over the whole visible wavelength range), ultralow sheet resistance to carrier injection (<5 Ω sq(-1)), and high tolerance to mechanical bending of the ameliorated plastic substrates synergistically optimize the device performance of FOLEDs. The maximum power efficiencies reach 47, 93, 56, and 52 lm W(-1) for red, green, blue, and white emissions, which are competitive with similarly structured OLEDs fabricated on traditional indium-tin-oxide (ITO) glass. This paradigm for light outcoupling enhancement in ITO-free FOLEDs offers additional features and design freedoms for highly efficient flexible optoelectronics in large-scale and low-cost manufacturing without the need for a high-refractive-index plastic substrate. PMID:26143652

  14. Structure and corrosion behavior of sputter deposited cerium oxide based coatings with various thickness on Al 2024-T3 alloy substrates

    NASA Astrophysics Data System (ADS)

    Liu, Yuanyuan; Huang, Jiamu; Claypool, James B.; Castano, Carlos E.; O'Keefe, Matthew J.

    2015-11-01

    Cerium oxide based coatings from ∼100 to ∼1400 nm in thickness were deposited onto Al 2024-T3 alloy substrates by magnetron sputtering of a 99.99% pure CeO2 target. The crystallite size of CeO2 coatings increased from 15 nm to 46 nm as the coating thickness increased from ∼100 nm to ∼1400 nm. The inhomogeneous lattice strain increased from 0.36% to 0.91% for the ∼100 nm to ∼900 nm thick coatings and slightly decreased to 0.89% for the ∼1400 nm thick coating. The highest adhesion strength to Al alloy substrates was for the ∼210 nm thick coating, due to a continuous film coverage and low internal stress. Electrochemical measurements indicated that sputter deposited crystalline CeO2 coatings acted as physical barriers that provide good cathodic inhibition for Al alloys in saline solution. The ∼900 nm thick CeO2 coated sample had the best corrosion performance that increased the corrosion resistance by two orders magnitude and lowered the cathodic current density 30 times compared to bare Al 2024-T3 substrates. The reduced defects and exposed surface, along with suppressed charge mobility, likely accounts for the improved corrosion performance as coating thickness increased from ∼100 nm to ∼900 nm. The corrosion performance decreased for ∼1400 nm thick coatings due in part to an increase in coating defects and porosity along with a decrease in adhesion strength.

  15. Influence of the oxide thickness of a SiO2/Si(001) substrate on the optical second harmonic intensity of few-layer MoSe2

    NASA Astrophysics Data System (ADS)

    Miyauchi, Yoshihiro; Morishita, Ryo; Tanaka, Masatoshi; Ohno, Sinya; Mizutani, Goro; Suzuki, Takanori

    2016-08-01

    The nonlinear optical properties of few-layer MoSe2 on a SiO2/Si substrate were investigated with our optical second harmonic generation (SHG) microscope. Few-layer flakes were mechanically exfoliated from a single crystal onto a 90- or 270-nm-thick SiO2-coated Si(001) substrate. The polar plot of the second-harmonic (SH) intensity from a mono- or trilayer MoSe2 flake as a function of the rotation angle of incident polarization shows a threefold symmetry, indicating that the isolated few-layer flakes retain their single crystallographic orientation. SHG spectra were found to depend strongly on the oxide thickness of the substrate (90 or 270 nm), which was interpreted using the interference among the multiply reflected SH light beams in the system. By taking this interference into account, a resonant peak may be identified at a two-photon energy of equal to or less than 2.9 eV in an SHG spectrum. The spatial resolution of the SHG microscope was estimated as 0.53 µm.

  16. Poly-crystallinity of indium-tin-oxide films improved by using simultaneous ion beam and heat treatment of the plastic substrate

    NASA Astrophysics Data System (ADS)

    Son, Phil Kook; Kim, Taehyung; Choi, Suk-Won; Gwag, Jin Seog

    2012-08-01

    The combined treatment effects of an ion beam with directionality and heat of a low temperature on a plastic substrate was investigated as a method to increase the electrical conductivity of indiumtin-oxide (ITO) films deposited on plastic substrate surfaces at low temperatures. Polyethylene terephthalate (PET) surface treatment by using an ion beam at low temperature (120 °C), which can be applied to plastic substrates, improves the conductivity of ITO films. X-ray diffraction indicates that ITO films deposited on PET surfaces treated simultaneously by using an ion beam and heat of a low temperature have an almost polycrystalline structure even though they have small amorphous party on. As a supplementary measurement, the contact angle showed that the polycrystalline structure was due to a self-assembly effect at the PET surfaces. Consequently, the electrical conductivity of an ITO film deposited by using the proposed technique is three times higher than that of an ITO film treated only with heat of low temperature due to the improved polycrystalline structure.

  17. Investigation into the role of NaCl deposited on oxide and metal substrates in the initiation of hot corrosion

    NASA Technical Reports Server (NTRS)

    Birks, N.

    1981-01-01

    Morphological aspects of the conversion to Na2SO4 of NaCl deposits over the temperature range 500-700 C, in air with added SO2 and H2O. Progress of the reaction was observed by withdrawing samples at various times and examining them under the scanning electron microscope using EDAX to assess the extent of chloride to sulfate conversion. These initial results show that the conversion to Na2SO4 proceeds directly on the sodium chloride surface as well as on the surrounding substrate due to evaporation of NaCl from the solid particle. The mechanism of this reaction could involve reaction in the vapor to produce Na2SO4 which then deposits, alternatively Na2SO4 could form directly on the substrate surface due to direct reaction there between the vapors NaCl, SO2 and O2.

  18. Fabrication of Vanadium Oxide Thin Films on Fused Quartz Substrates by Metal-Organic Decomposition for Bolometer Detectors

    NASA Astrophysics Data System (ADS)

    Son, Le Ngoc; Tachiki, Takashi; Uchida, Takashi

    2012-08-01

    Axis-oriented V2O5 thin films were prepared on fused quartz substrates by metal-organic decomposition (MOD). Then these films were reduced to VOx thin films by heat treatment at a temperature of 530 °C and a pressure of 1.2 Pa in O2. The obtained VOx thin films exhibited an abrupt phase transition with a resistivity change of up to 4 orders of magnitude. These VOx films had a high temperature coefficient of resistance (TCR) of up to 4.8%/K at 300 K and these values were over two times higher than those of the films fabricated on SiO2/Si substrates.

  19. Process modeling and analysis of structure and stoichiometry of magnesium oxide nano thin films grown by molecular beam epitaxy on 6 hydrogen-silicon carbide substrates

    NASA Astrophysics Data System (ADS)

    Uddin, Ghulam Moeen

    In recent years there has been an increasing interest in effective integration of nano scale functional oxides with semiconductors for third and fourth generation nano devices including high-K dielectrics based electronic devices and paradigm-shifting spintronics-based circuits. In this research we investigate the growth of MgO nano thin films on 6H-SiC substrate in a molecular beam epitaxy process. Here MgO serves as a template layer to minimize the mismatch with both substrate and a functional oxide films such as BTO and BaM. In this research we constructed neural network based process models using historical experimental data. Based on these process models we performed structural and stoichiometric analyses through both design of experiments and Monte Carlo simulation. We found that the percentage starting oxygen on the substrate is the most critical variable that promotes the undesired bonding states, i.e., Mg-OH and excessive strain in film crystalline structure. In addition the impact of percentage of starting oxygen on structure and stoichiometry is affected by the film thickness. The interaction between substrate temperature and oxygen on the starting substrate surface is the critical pair that affects the dynamics of Mg-OH bonding state. This study helped us analyze the process behavior and gain process knowledge to conduct systematic experimentation. After conducting the systematic experiments we quantitatively studied the causal relationship the undesired bonding states and the percentage starting oxygen at 3 levels of film thickness. Moreover, the cleaning of silicon carbide (6H-SiC) substrate surface is an essential and important step to grow MgO films with minimum undesired bonding states. We investigated high temperature hydrogen etching process to clean the substrate surface. In this research we studied the impact of cleaning time and cleaning temperature by analyzing the reflection high energy electron diffraction (RHEED) structural performance

  20. Laser-induced oxidation of titanium substrate: Analysis of the physicochemical structure of the surface and sub-surface layers

    NASA Astrophysics Data System (ADS)

    Antończak, Arkadiusz J.; Skowroński, Łukasz; Trzcinski, Marek; Kinzhybalo, Vasyl V.; Łazarek, Łukasz K.; Abramski, Krzysztof M.

    2015-01-01

    This paper presents the results of the analysis of the complex chemical structure of the layers made on titanium in the process of the heating of its surfaces in an atmospheric environment, by irradiating samples with a nanosecond-pulsed laser. The study was carried out for electroplated, high purity, polycrystalline titanium substrates using a Yb:glass fiber laser. All measurements were made for samples irradiated in a broad range of accumulated fluence, below the ablation threshold. It has been determined how the complex index of refraction of both the oxynitride layers and the substrate vary as a function of accumulated laser fluence. It was also shown that the top layer of the film produced on titanium, which is transparent, is not a pure TiO2 as had been supposed before. The XPS and XRD analyses confirmed the presence of nitrogen compounds and the existence of nonstoichiometric compounds. By sputtering of the sample's surface using an Ar+ ion gun, the changes in the concentration of individual elements as a function of the layer's cross-section were determined. Lastly, an analysis of the surface morphology has also been carried out, explaining why the layers crack and exfoliate from their substrate.

  1. Microwave-assisted green synthesis of Ag/reduced graphene oxide nanocomposite as a surface-enhanced Raman scattering substrate with high uniformity

    NASA Astrophysics Data System (ADS)

    Hsu, Kai-Chih; Chen, Dong-Hwang

    2014-04-01

    A nanocomposite of silver nanoparticles/reduced graphene oxide (Ag/rGO) has been fabricated as a surface-enhanced Raman scattering (SERS) substrate owing to the large surface area and two-dimensional nanosheet structure of rGO. A facile and rapid microwave-assisted green route has been used for the formation of Ag nanoparticles and the reduction of graphene oxide simultaneously with L-arginine as the reducing agent. By increasing the cycle number of microwave irradiation from 1 and 4 to 8, the mean diameters of Ag nanoparticles deposited on the surface of rGO increased from 10.3 ± 4.6 and 21.4 ± 10.5 to 41.1 ± 12.6 nm. The SERS performance of Ag/rGO nanocomposite was examined using the common Raman reporter molecule 4-aminothiophenol (4-ATP). It was found that the Raman intensity of 4-ATP could be significantly enhanced by increasing the size and content of silver nanoparticles deposited on rGO. Although the Raman intensities of D-band and G-band of rGO were also enhanced simultaneously by the deposited Ag nanoparticles which limited the further improvement of SERS detection sensitivity, the detectable concentration of 4-ATP with Ag/rGO nanocomposite as the SERS substrate still could be lowered to be 10-10 M and the enhancement factor could be increased to 1.27 × 1010. Furthermore, it was also achievable to lower the relative standard deviation (RSD) values of the Raman intensities to below 5%. This revealed that the Ag/rGO nanocomposite obtained in this work could be used as a SERS substrate with high sensitivity and homogeneity.

  2. Epitaxial growth of zinc oxide by the method of atomic layer deposition on SiC/Si substrates

    NASA Astrophysics Data System (ADS)

    Kukushkin, S. A.; Osipov, A. V.; Romanychev, A. I.

    2016-07-01

    For the first time, zinc oxide epitaxial films on silicon were grown by the method of atomic layer deposition at a temperature T = 250°C. In order to avoid a chemical reaction between silicon and zinc oxide (at the growth temperature, the rate constant of the reaction is of the order of 1022), a high-quality silicon carbide buffer layer with a thickness of ~50 nm was preliminarily synthesized by the chemical substitution of atoms on the silicon surface. The zinc oxide films were grown on n- and p-type Si(100) wafers. The ellipsometric, Raman, electron diffraction, and trace element analyses showed that the ZnO films are epitaxial.

  3. Do ketogenic diets really suppress appetite? A systematic review and meta-analysis.

    PubMed

    Gibson, A A; Seimon, R V; Lee, C M Y; Ayre, J; Franklin, J; Markovic, T P; Caterson, I D; Sainsbury, A

    2015-01-01

    Very-low-energy diets (VLEDs) and ketogenic low-carbohydrate diets (KLCDs) are two dietary strategies that have been associated with a suppression of appetite. However, the results of clinical trials investigating the effect of ketogenic diets on appetite are inconsistent. To evaluate quantitatively the effect of ketogenic diets on subjective appetite ratings, we conducted a systematic literature search and meta-analysis of studies that assessed appetite with visual analogue scales before (in energy balance) and during (while in ketosis) adherence to VLED or KLCD. Individuals were less hungry and exhibited greater fullness/satiety while adhering to VLED, and individuals adhering to KLCD were less hungry and had a reduced desire to eat. Although these absolute changes in appetite were small, they occurred within the context of energy restriction, which is known to increase appetite in obese people. Thus, the clinical benefit of a ketogenic diet is in preventing an increase in appetite, despite weight loss, although individuals may indeed feel slightly less hungry (or more full or satisfied). Ketosis appears to provide a plausible explanation for this suppression of appetite. Future studies should investigate the minimum level of ketosis required to achieve appetite suppression during ketogenic weight loss diets, as this could enable inclusion of a greater variety of healthy carbohydrate-containing foods into the diet. PMID:25402637

  4. Ultra-thin body & buried oxide SOI substrate development and qualification for Fully Depleted SOI device with back bias capability

    NASA Astrophysics Data System (ADS)

    Schwarzenbach, Walter; Nguyen, Bich-Yen; Allibert, Frederic; Girard, Christophe; Maleville, Christophe

    2016-03-01

    This paper reviews the properties of the SOI wafers fabricated using the Smart Cut™ technology, with ultra-thin body and buried oxide (BOX) required for the FD-SOI CMOS platform. It focuses on the parameters that require specific attention for this technology, namely, the top silicon layer thickness uniformity and buried oxide reliability. The first one is linked to the threshold voltage variability and the second to the active role played by the BOX when a back-bias is used. An overview of the specific process optimization and metrology developed to achieve the targeted specifications is given.

  5. Effect of the substrate temperature on the physical properties of molybdenum tri-oxide thin films obtained through the spray pyrolysis technique

    SciTech Connect

    Martinez, H.M.; Torres, J.; Lopez Carreno, L.D.; Rodriguez-Garcia, M.E.

    2013-01-15

    Polycrystalline molybdenum tri-oxide thin films were prepared using the spray pyrolysis technique; a 0.1 M solution of ammonium molybdate tetra-hydrated was used as a precursor. The samples were prepared on Corning glass substrates maintained at temperatures ranging between 423 and 673 K. The samples were characterized through micro Raman, X-ray diffraction, optical transmittance and DC electrical conductivity. The species MoO{sub 3} (H{sub 2}O){sub 2} was found in the sample prepared at a substrate temperature of 423 K. As the substrate temperature rises, the water disappears and the samples crystallize into {alpha}-MoO{sub 3}. The optical gap diminishes as the substrate temperature rises. Two electrical transport mechanisms were found: hopping under 200 K and intrinsic conduction over 200 K. The MoO{sub 3} films' sensitivity was analyzed for CO and H{sub 2}O in the temperature range 160 to 360 K; the results indicate that CO and H{sub 2}O have a reduction character. In all cases, it was found that the sensitivity to CO is lower than that to H{sub 2}O. - Highlights: Black-Right-Pointing-Pointer A low cost technique is used which produces good material. Black-Right-Pointing-Pointer Thin films are prepared using ammonium molybdate tetra hydrated. Black-Right-Pointing-Pointer The control of the physical properties of the samples could be done. Black-Right-Pointing-Pointer A calculation method is proposed to determine the material optical properties. Black-Right-Pointing-Pointer The MoO{sub 3} thin films prepared by spray pyrolysis could be used as gas sensor.

  6. Use resources of human exometabolites of different oxidation levels for higher plants cultivation on the soil-like substrate as applied to closed ecosystems

    NASA Astrophysics Data System (ADS)

    Tikhomirov, Alexander A.; Kudenko, Yurii; Ushakova, Sofya; Tirranen, Lyalya; Gribovskaya, Illiada; Gros, Jean-Bernard; Lasseur, Christophe

    The technology of ‘wet incineration' of human exometabolites and inedible plants biomass by means of H2 O2 in alternating electromagnetic field to increase a closure of mass exchange processes in bioregenerative life support systems (BLSS) was developed at the Institute of Biophysics of the Siberian Branch of Russian Academy of Sciences (Krasnoyarsk, Russia). Human exometabolites mineralized can be used in a nutrient solution for plants cultivation in the BLSS phototrophic link. The objective of the given work appears to be the study of use resources of human exometabolites of different oxidation levels processed by the abovementioned method for higher plants cultivation on the soil-like substrate (SLS). The mineralized human wastes were tested for the purpose of their sterility. Then the effect of human exometabolites of different oxidation levels both on wheat productivity and on the SLS microflora composition was examined. The SLS extract with a definite amount of human mineralized wastes was used as an irrigation solution. The conducted experiments demonstrated that the H2 O2 decreasing to 1 ml on 1 g of feces and to 0.25 ml on 1 ml of urine had not affected the sterility of mineralized human wastes. Wheat cultivation on the SLS with the addition in an irrigation solution of mineralized human wastes in the amount simulating 1/6 of a daily human diet showed the absence of basic dependence of plants productivity on oxidation level of human exometabolites. Yet the analysis of the microflora composition of the irrigation solutions demonstrated its dependence on the oxidation level of the exometabolites introduced. The amount of yeast-like fungi increased in 20 times in the solutions containing less oxidized exometabolites in comparison with the variant in which the human wastes were subjected to a full-scale oxidation. Besides, the solutions with less oxidized exometabolites displayed a bigger content of plant pathogenic bacteria and denitrifies. Consequently the

  7. Fabrication of p-type porous silicon nanowire with oxidized silicon substrate through one-step MACE

    NASA Astrophysics Data System (ADS)

    Li, Shaoyuan; Ma, Wenhui; Zhou, Yang; Chen, Xiuhua; Xiao, Yongyin; Ma, Mingyu; Wei, Feng; Yang, Xi

    2014-05-01

    In this paper, the simple pre-oxidization process is firstly used to treat the starting silicon wafer, and then MPSiNWs are successfully fabricated from the moderately doped wafer by one-step MACE technology in HF/AgNO3 system. The PL spectrum of MPSiNWs obtained from the oxidized silicon wafers show a large blue-shift, which can be attributed to the deep Q. C. effect induced by numerous mesoporous structures. The effects of HF and AgNO3 concentration on formation of SiNWs were carefully investigated. The results indicate that the higher HF concentration is favorable to the growth of SiNWs, and the density of SiNWs is significantly reduced when Ag+ ions concentrations are too high. The deposition behaviors of Ag+ ions on oxidized and unoxidized silicon surface were studied. According to the experimental results, a model was proposed to explain the formation mechanism of porous SiNWs by etching the oxidized starting silicon.

  8. Appetite control and energy balance: impact of exercise.

    PubMed

    Blundell, J E; Gibbons, C; Caudwell, P; Finlayson, G; Hopkins, M

    2015-02-01

    Exercise is widely regarded as one of the most valuable components of behaviour that can influence body weight and therefore help in the prevention and management of obesity. Indeed, long-term controlled trials show a clear dose-related effect of exercise on body weight. However, there is a suspicion, particularly fuelled by media reports, that exercise serves to increase hunger and drive up food intake thereby nullifying the energy expended through activity. Not everyone performing regular exercise will lose weight and several investigations have demonstrated a huge individual variability in the response to exercise regimes. What accounts for this heterogeneous response? First, exercise (or physical activity) through the expenditure of energy will influence the energy balance equation with the potential to generate an energy deficit. However, energy expenditure also influences the control of appetite (i.e. the physiological and psychological regulatory processes underpinning feeding) and energy intake. This dynamic interaction means that the prediction of a resultant shift in energy balance, and therefore weight change, will be complicated. In changing energy intake, exercise will impact on the biological mechanisms controlling appetite. It is becoming recognized that the major influences on the expression of appetite arise from fat-free mass and fat mass, resting metabolic rate, gastric adjustment to ingested food, changes in episodic peptides including insulin, ghrelin, cholecystokinin, glucagon-like peptide-1 and tyrosine-tyrosine, as well as tonic peptides such as leptin. Moreover, there is evidence that exercise will influence all of these components that, in turn, will influence the drive to eat through the modulation of hunger (a conscious sensation reflecting a mental urge to eat) and adjustments in postprandial satiety via an interaction with food composition. The specific actions of exercise on each physiological component will vary in strength from

  9. Effect of viscosity on appetite and gastro-intestinal hormones.

    PubMed

    Zijlstra, Nicolien; Mars, Monica; de Wijk, René A; Westerterp-Plantenga, Margriet S; Holst, Jens Juul; de Graaf, Cees

    2009-04-20

    In previous studies we showed that higher viscosity resulted in lower ad libitum intake and that eating rate is an important factor. In this study we aimed to explore the effect of viscosity on the gastro-intestinal hormones ghrelin, CCK-8 and GLP-1. Thirty-two subjects (22+/-2 y, BMI 21.9+/-2.2 kg/m(2)) participated in this cross-over study. Subjects received a fixed amount of a chocolate flavored milk-based liquid or semi-solid product similar in energy density and macronutrient composition. Before intake and 15, 30, 60 and 90 min thereafter, appetite was rated and blood was drawn to determine glucose, CCK-8, active ghrelin, desacyl ghrelin and GLP-1 concentrations. After the last blood withdrawal, subjects were offered a chocolate cake meal to consume ad libitum. In the appetite ratings we observed a small effect showing that the semi-solid product is apparently considered as more satisfying than the liquid. There was a significant product effect for fullness (p 0.03), desire to eat (p 0.04), appetite something sweet (p 0.002) and prospective consumption (p 0.0009). We observed no clear effect of viscosity on gastro-intestinal hormones. Only for desacyl ghrelin there was a significant product effect (p 0.004). Concentrations were consistently higher after intake of the semi-solid product. Ad libitum intake of the chocolate cake was 102+/-55 g after the liquid and 96+/-46 g after the semi-solid product (ns). The results of our study show a similar response of the gastro-intestinal hormones CCK-8, ghrelin and GLP-1 after a fixed preload of a liquid and semi-solid product similar in energy- and macronutrient composition. PMID:19419670

  10. Electrolyte supported solid oxide fuel cells with the super large size and thin ytterbia stabilized zirconia substrate

    NASA Astrophysics Data System (ADS)

    Xue, Ye Jian; Miao, He; He, Chang Rong; Wang, Jian Xin; Liu, Man; Sun, Shan Shan; Wang, Qin; Wang, Wei Guo

    2015-04-01

    In this work, the (ZrO2)0.95(Yb2O3)0.05(5YbSZ) electrolyte supported SOFCs with the large area of 10 cm × 10 cm and thin substrate of about 70 μm are prepared, and the microstructures, electrochemical and anti-redox properties of the single cells are investigated systematically. The powders of 5YbSZ with the tetragonal and cubic mixed phase are synthesized by the so-called "solid-liquid composite method" at a somewhat low temperature of 1100 °C. The 5YbSZ electrolyte substrates which are prepared by the tape-casting, multilayer-lamination and sintering method showed the optimal comprehensive performances with the sintering temperature being 1500 °C. By using these electrolyte substrates, the NiO+GDC/5YbSZ/LSM+5YbSZ single cells are obtained at the co-sinter temperature of 1100 °C. The power densities of these cells can reach 0.56 W cm-2 at the output voltage of 0.7 V, and the degradation rate can attain 1.45% kh-1 under a constant current density of 0.2 A cm-2 at the temperature of 830 °C. After 11 redox cycles, no crack through the 5YbSZ electrolyte can be found in the single cells, and the electrochemical properties of the 5YbSZ electrolyte supported single cells show an acceptable degradation.

  11. Hierarchical cupric oxide nanostructures on copper substrate for cold cathode emission: an experimental venture with theoretical correlation.

    PubMed

    Das, Swati; Saha, Subhajit; Sen, Dipayan; Ghorai, Uttam Kumar; Chattopadhyay, Kalyan Kumar

    2015-04-01

    In this paper we report a facile route for the synthesis of controlled CuO nanoarchitectures directly grown on a copper substrate by a one-step simple chemical route with varying concentration of non-ionic surfactant PEG-6K. The phase purity and degree of crystallinity of the as-developed nanostructures were systemically investigated by X-ray diffraction, X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy (HRTEM). A detailed analysis by field emission scanning electron microscopy confirmed the uniformity of the prepared nanostructures on the substrates. These architectures displayed substantial improvement of field emission properties with respect to other structures of CuO reported so far. A particular nanostructure (needle) among them showed a down shift of the turn-on field to 2.2 V μm(-1) coupled with a good enhancement factor (β) ∼516, which are deemed as sufficient for electron emission based applications such as field emission displays and vacuum nanoelectronic devices. The origin of this efficient field emission from CuO nanoarchitectures, were probed computationally by investigating the local electric field distribution through finite element based simulation method using the ANSYS Maxwell simulation package. PMID:25727565

  12. Substrate biasing effect on the physical properties of reactive RF-magnetron-sputtered aluminum oxide dielectric films on ITO glasses.

    PubMed

    Liang, Ling Yan; Cao, Hong Tao; Liu, Quan; Jiang, Ke Min; Liu, Zhi Min; Zhuge, Fei; Deng, Fu Ling

    2014-02-26

    High dielectric constant (high-k) Al2O3 thin films were prepared on ITO glasses by reactive RF-magnetron sputtering at room temperature. The effect of substrate bias on the subband structural, morphological, electrode/Al2O3 interfacial and electrical properties of the Al2O3 films is systematically investigated. An optical method based on spectroscopic ellipsometry measurement and modeling is adopted to probe the subband electronic structure, which facilitates us to vividly understand the band-tail and deep-level (4.8-5.0 eV above the valence band maximum) trap states. Well-selected substrate biases can suppress both the trap states due to promoted migration of sputtered particles, which optimizes the leakage current density, breakdown strength, and quadratic voltage coefficient of capacitance. Moreover, high porosity in the unbiased Al2O3 film is considered to induce the absorption of atmospheric moisture and the consequent occurrence of electrolysis reactions at electrode/Al2O3 interface, as a result ruining the electrical properties. PMID:24490685

  13. Exercise-Trained Men and Women: Role of Exercise and Diet on Appetite and Energy Intake

    PubMed Central

    Howe, Stephanie M.; Hand, Taryn M.; Manore, Melinda M.

    2014-01-01

    The regulation of appetite and energy intake is influenced by numerous hormonal and neural signals, including feedback from changes in diet and exercise. Exercise can suppress subjective appetite ratings, subsequent energy intake, and alter appetite-regulating hormones, including ghrelin, peptide YY, and glucagon-like peptide 1(GLP-1) for a period of time post-exercise. Discrepancies in the degree of appetite suppression with exercise may be dependent on subject characteristics (e.g., body fatness, fitness level, age or sex) and exercise duration, intensity, type and mode. Following an acute bout of exercise, exercise-trained males experience appetite suppression, while data in exercise-trained women are limited and equivocal. Diet can also impact appetite, with low-energy dense diets eliciting a greater sense of fullness at a lower energy intake. To date, little research has examined the combined interaction of exercise and diet on appetite and energy intake. This review focuses on exercise-trained men and women and examines the impact of exercise on hormonal regulation of appetite, post-exercise energy intake, and subjective and objective measurements of appetite. The impact that low-energy dense diets have on appetite and energy intake are also addressed. Finally, the combined effects of high-intensity exercise and low-energy dense diets are examined. This research is in exercise-trained women who are often concerned with weight and body image issues and consume low-energy dense foods to keep energy intakes low. Unfortunately, these low-energy intakes can have negative health consequences when combined with high-levels of exercise. More research is needed examining the combined effect of diet and exercise on appetite regulation in fit, exercise-trained individuals. PMID:25389897

  14. Bottom-up synthesis of ordered metal/oxide/metal nanodots on substrates for nanoscale resistive switching memory

    NASA Astrophysics Data System (ADS)

    Han, Un-Bin; Lee, Jang-Sik

    2016-05-01

    The bottom-up approach using self-assembled materials/processes is thought to be a promising solution for next-generation device fabrication, but it is often found to be not feasible for use in real device fabrication. Here, we report a feasible and versatile way to fabricate high-density, nanoscale memory devices by direct bottom-up filling of memory elements. An ordered array of metal/oxide/metal (copper/copper oxide/copper) nanodots was synthesized with a uniform size and thickness defined by self-organized nanotemplate mask by sequential electrochemical deposition (ECD) of each layer. The fabricated memory devices showed bipolar resistive switching behaviors confirmed by conductive atomic force microscopy. This study demonstrates that ECD with bottom-up growth has great potential to fabricate high-density nanoelectronic devices beyond the scaling limit of top-down device fabrication processes.

  15. Bottom-up synthesis of ordered metal/oxide/metal nanodots on substrates for nanoscale resistive switching memory.

    PubMed

    Han, Un-Bin; Lee, Jang-Sik

    2016-01-01

    The bottom-up approach using self-assembled materials/processes is thought to be a promising solution for next-generation device fabrication, but it is often found to be not feasible for use in real device fabrication. Here, we report a feasible and versatile way to fabricate high-density, nanoscale memory devices by direct bottom-up filling of memory elements. An ordered array of metal/oxide/metal (copper/copper oxide/copper) nanodots was synthesized with a uniform size and thickness defined by self-organized nanotemplate mask by sequential electrochemical deposition (ECD) of each layer. The fabricated memory devices showed bipolar resistive switching behaviors confirmed by conductive atomic force microscopy. This study demonstrates that ECD with bottom-up growth has great potential to fabricate high-density nanoelectronic devices beyond the scaling limit of top-down device fabrication processes. PMID:27157385

  16. Bottom-up synthesis of ordered metal/oxide/metal nanodots on substrates for nanoscale resistive switching memory

    PubMed Central

    Han, Un-Bin; Lee, Jang-Sik

    2016-01-01

    The bottom-up approach using self-assembled materials/processes is thought to be a promising solution for next-generation device fabrication, but it is often found to be not feasible for use in real device fabrication. Here, we report a feasible and versatile way to fabricate high-density, nanoscale memory devices by direct bottom-up filling of memory elements. An ordered array of metal/oxide/metal (copper/copper oxide/copper) nanodots was synthesized with a uniform size and thickness defined by self-organized nanotemplate mask by sequential electrochemical deposition (ECD) of each layer. The fabricated memory devices showed bipolar resistive switching behaviors confirmed by conductive atomic force microscopy. This study demonstrates that ECD with bottom-up growth has great potential to fabricate high-density nanoelectronic devices beyond the scaling limit of top-down device fabrication processes. PMID:27157385

  17. Crystal Structure and Substrate Recognition of Cellobionic Acid Phosphorylase, Which Plays a Key Role in Oxidative Cellulose Degradation by Microbes*

    PubMed Central

    Nam, Young-Woo; Nihira, Takanori; Arakawa, Takatoshi; Saito, Yuka; Kitaoka, Motomitsu; Nakai, Hiroyuki; Fushinobu, Shinya

    2015-01-01

    The microbial oxidative cellulose degradation system is attracting significant research attention after the recent discovery of lytic polysaccharide mono-oxygenases. A primary product of the oxidative and hydrolytic cellulose degradation system is cellobionic acid (CbA), the aldonic acid form of cellobiose. We previously demonstrated that the intracellular enzyme belonging to glycoside hydrolase family 94 from cellulolytic fungus and bacterium is cellobionic acid phosphorylase (CBAP), which catalyzes reversible phosphorolysis of CbA into glucose 1-phosphate and gluconic acid (GlcA). In this report, we describe the biochemical characterization and the three-dimensional structure of CBAP from the marine cellulolytic bacterium Saccharophagus degradans. Structures of ligand-free and complex forms with CbA, GlcA, and a synthetic disaccharide product from glucuronic acid were determined at resolutions of up to 1.6 Å. The active site is located near the dimer interface. At subsite +1, the carboxylate group of GlcA and CbA is recognized by Arg-609 and Lys-613. Additionally, one residue from the neighboring protomer (Gln-190) is involved in the carboxylate recognition of GlcA. A mutational analysis indicated that these residues are critical for the binding and catalysis of the aldonic and uronic acid acceptors GlcA and glucuronic acid. Structural and sequence comparisons with other glycoside hydrolase family 94 phosphorylases revealed that CBAPs have a unique subsite +1 with a distinct amino acid residue conservation pattern at this site. This study provides molecular insight into the energetically efficient metabolic pathway of oxidized sugars that links the oxidative cellulolytic pathway to the glycolytic and pentose phosphate pathways in cellulolytic microbes. PMID:26041776

  18. Evidence for separate substrate binding sites for hydrogen peroxide and cumene hydroperoxide (CHP) in the oxidation of ethanol by catalase

    SciTech Connect

    DeMaster, E.G.; Nagasawa,ss H.T.

    1986-03-01

    The oxidation of ethanol by purified bovine liver catalase (Sigma, C-40) can be supported by H/sub 2/O/sub 2/ or by CHP. The time course of the H/sub 2/O/sub 2/ supported reaction (using glucose/glucose oxidase as the H/sub 2/O/sub 2/ source) was linear for at least one hr, whereas the rate of acetaldehyde formation in the CHP (4.2 mM) supported reaction decreased with time. When catalase was exposed o CHP for 5 min before the addition of ethanol, the rate of CHP supported ethanol oxidation was reduced by more than 90% compared to incubations where the addition of ethanol preceded that of CHP. In the CHP inhibited state, the peroxidative activity of catalase was not restored by further addition of CHP or ethanol; however, addition of fresh catalase yielded its expected activity. Significantly, the CHP inhibited enzyme was equally effective as the untreated enzyme in catalyzing (a) the oxidation of ethanol in the presence H/sub 2/O/sub 2/ supported peroxidative activity as well as catalytic activity by CHP inhibited catalase points to separate binding sites for H/sub 2/O/sub 2/ and CHP in this reaction. Alternatively, CHP may bind adjacent to a common peroxide active site, thereby sterically impeding the binding of CHP - but not of H/sub 2/O/sub 2/ - to this active site.

  19. Cocaine's appetite for fat and the consequences on body weight.

    PubMed

    Billing, Lawrence; Ersche, Karen D

    2015-03-01

    For many individuals in treatment for cocaine dependence, weight gain is a substantial problem during recovery. This weight gain causes significant distress and seems to increase the risk of relapse. The mechanisms underlying cocaine's effects on weight remain elusive. It is widely assumed that this weight gain reflects a metabolic or behavioural compensatory response to the cessation of cocaine use. Here we challenge this assumption and outline potential mechanisms by which chronic cocaine use produces disturbances in the regulation of fat intake and storage, through its effects on the central and peripheral nervous systems, specifically the sympathetic nervous system. We hypothesize that the cocaine-induced alteration in fat regulation results in cocaine users developing a pronounced appetite for fatty food but keeps their fat mass low. This altered fat appetite subsequently leads to excessive weight gain when individuals enter treatment and stop using cocaine. Our aim is to shed light on the neurobiological mechanisms that may underlie the alterations in eating and fat regulation in cocaine-dependent individuals, to open up potential new avenues to support these individuals in recovery. PMID:25321424

  20. Peripheral Insulin Doesn’t Alter Appetite of Broiler Chicks

    PubMed Central

    Liu, Lei; Xu, Shaohua; Wang, Xiaojuan; Jiao, Hongchao; Lin, Hai

    2016-01-01

    An experiment was conducted to investigate the effect of peripheral insulin treatment on appetite in chicks. Six-d-age chicks with ad libitum feeding or fasting for 3 h before injection received a subcutaneous injection of 0, 1, 3, 5, 10, or 20 IU of insulin or vehicle (saline). The results showed peripheral insulin treatment (1 to 20 IU) did not alter significantly the feed intake in chicks under either ad libitum feeding or fasting conditions within 4 h (p>0.05). Compared with the control, plasma glucose concentration was significantly decreased after insulin treatment of 3, 5, 10, and 20 IU for 4 h in chicks with ad libitum feeding (p<0.05). In fasted chicks, 10 and 20 IU insulin treatments significantly decreased the plasma glucose level for 4 h (p<0.05). Peripheral insulin treatment of 10 IU for 2 or 4 h did not significantly affect the hypothalamic genes expression of neuropeptide Y, proopiomelanocortin, corticotropin-releasing factor and insulin receptors (p>0.05). All results suggest peripheral administration of insulin has no effect on appetite in chicks. PMID:26954230

  1. Peripheral Insulin Doesn't Alter Appetite of Broiler Chicks.

    PubMed

    Liu, Lei; Xu, Shaohua; Wang, Xiaojuan; Jiao, Hongchao; Lin, Hai

    2016-09-01

    An experiment was conducted to investigate the effect of peripheral insulin treatment on appetite in chicks. Six-d-age chicks with ad libitum feeding or fasting for 3 h before injection received a subcutaneous injection of 0, 1, 3, 5, 10, or 20 IU of insulin or vehicle (saline). The results showed peripheral insulin treatment (1 to 20 IU) did not alter significantly the feed intake in chicks under either ad libitum feeding or fasting conditions within 4 h (p>0.05). Compared with the control, plasma glucose concentration was significantly decreased after insulin treatment of 3, 5, 10, and 20 IU for 4 h in chicks with ad libitum feeding (p<0.05). In fasted chicks, 10 and 20 IU insulin treatments significantly decreased the plasma glucose level for 4 h (p<0.05). Peripheral insulin treatment of 10 IU for 2 or 4 h did not significantly affect the hypothalamic genes expression of neuropeptide Y, proopiomelanocortin, corticotropin-releasing factor and insulin receptors (p>0.05). All results suggest peripheral administration of insulin has no effect on appetite in chicks. PMID:26954230

  2. Salt Appetite: Interaction of Forebrain Angiotensinergic and Hindbrain Serotonergic Mechanisms

    NASA Technical Reports Server (NTRS)

    Menani, Jose Vanderlei; Colombari, Debora S. A.; Beltz, Terry G.; Thunhorst, Robert L.; Johnson, Alan Kim

    1998-01-01

    Methysergide injected into the lateral parabrachial nucleus (LPBN) increases the salt appetite of rats depleted of sodium by furosemide (FURO). The present study investigated the effects of angiotensin 2 (ANG 2) receptor blockade in the subfornical organ (SFO) on this increased salt appetite. The intake of 0.3 M NaCl and water was induced by combined administration of the diuretic, FURO, and the angiotensin-convertina, enzyme inhibitor, captopril (CAP). Pretreatment of the SFO with the anciotensin Type 1 (AT,) receptor antagonist, losartan (1 microgram/200 nl), reduced water intake but not 0.3 M NaCl intake induced by subcutaneous FURO+ CAP. Methysergide (4 microgram/200 nl) injected bilaterally into the LPBN increased 0.3 M NaCl intake after FURO + CAP. Losartan injected into the SFO prevented additional 0.3 M NaCl intake caused by methysergide injections into the LPBN. These results indicate that AT, receptors located in the SFO may have a role in mediatina the intake of sodium and water induced by sodium depletion. They also suggest that after treatment with FURO + CAP an LPBN-associated scrotonergic mechanism inhibits increased sodium intake.

  3. On the properties of aluminium doped zinc oxide thin films deposited on plastic substrates from ceramic targets

    NASA Astrophysics Data System (ADS)

    Girtan, M.; Vlad, A.; Mallet, R.; Bodea, M. A.; Pedarnig, J. D.; Stanculescu, A.; Mardare, D.; Leontie, L.; Antohe, S.

    2013-06-01

    We report on the deposition of Al doped ZnO (AZO) thin films on unheated polyethylene terephthalate (PET) substrates by pulsed laser deposition technique using a UV excimer laser and Al2O3:ZnO ceramic targets (1.5 and 2 wt% Al2O3). The deposited AZO films have been investigated by atomic force microscopy, scanning electron microscopy, X-ray diffraction, and optical spectrophotometry. Films present excellent optical and electrical properties (transmission in the visible range T > 85%; resistivity at room temperature ρ = 1.3 × 10-3 Ω cm) as electrodes for plastic solar cells. A good correlation was found between deposition conditions (laser fluence) and structural, morphological, optical and electrical properties.

  4. Highest transmittance and high-mobility amorphous indium gallium zinc oxide films on flexible substrate by room-temperature deposition and post-deposition anneals

    SciTech Connect

    Gadre, Mandar J.; Alford, T. L.

    2011-08-01

    Amorphous indium gallium zinc oxide (a-IGZO) thin films of the highest transmittance reported in literature were initially deposited onto flexible polymer substrates at room temperature. The films were annealed in vacuum, air, and oxygen to enhance their electrical and optical performances. Electrical and optical characterizations were done before and after anneals. A partial reversal of the degradation in electrical properties upon annealing in oxygen was achieved by subjecting the films to subsequent vacuum anneals. A model was developed based on film texture and structural defects which showed close agreement between the measured and calculated carrier mobility values at low carrier concentrations (2-6 x 10{sup 19} cm{sup -3}).

  5. Continuous-flow Mass Production of Silicon Nanowires via Substrate-Enhanced Metal-Catalyzed Electroless Etching of Silicon with Dissolved Oxygen as an Oxidant

    NASA Astrophysics Data System (ADS)

    Hu, Ya; Peng, Kui-Qing; Liu, Lin; Qiao, Zhen; Huang, Xing; Wu, Xiao-Ling; Meng, Xiang-Min; Lee, Shuit-Tong

    2014-01-01

    Silicon nanowires (SiNWs) are attracting growing interest due to their unique properties and promising applications in photovoltaic devices, thermoelectric devices, lithium-ion batteries, and biotechnology. Low-cost mass production of SiNWs is essential for SiNWs-based nanotechnology commercialization. However, economic, controlled large-scale production of SiNWs remains challenging and rarely attainable. Here, we demonstrate a facile strategy capable of low-cost, continuous-flow mass production of SiNWs on an industrial scale. The strategy relies on substrate-enhanced metal-catalyzed electroless etching (MCEE) of silicon using dissolved oxygen in aqueous hydrofluoric acid (HF) solution as an oxidant. The distinct advantages of this novel MCEE approach, such as simplicity, scalability and flexibility, make it an attractive alternative to conventional MCEE methods.

  6. Continuous-flow Mass Production of Silicon Nanowires via Substrate-Enhanced Metal-Catalyzed Electroless Etching of Silicon with Dissolved Oxygen as an Oxidant

    PubMed Central

    Hu, Ya; Peng, Kui-Qing; Liu, Lin; Qiao, Zhen; Huang, Xing; Wu, Xiao-Ling; Meng, Xiang-Min; Lee, Shuit-Tong

    2014-01-01

    Silicon nanowires (SiNWs) are attracting growing interest due to their unique properties and promising applications in photovoltaic devices, thermoelectric devices, lithium-ion batteries, and biotechnology. Low-cost mass production of SiNWs is essential for SiNWs-based nanotechnology commercialization. However, economic, controlled large-scale production of SiNWs remains challenging and rarely attainable. Here, we demonstrate a facile strategy capable of low-cost, continuous-flow mass production of SiNWs on an industrial scale. The strategy relies on substrate-enhanced metal-catalyzed electroless etching (MCEE) of silicon using dissolved oxygen in aqueous hydrofluoric acid (HF) solution as an oxidant. The distinct advantages of this novel MCEE approach, such as simplicity, scalability and flexibility, make it an attractive alternative to conventional MCEE methods. PMID:24413157

  7. Indium-tin oxide thin films deposited at room temperature on glass and PET substrates: Optical and electrical properties variation with the H2-Ar sputtering gas mixture

    NASA Astrophysics Data System (ADS)

    Álvarez-Fraga, L.; Jiménez-Villacorta, F.; Sánchez-Marcos, J.; de Andrés, A.; Prieto, C.

    2015-07-01

    The optical and electrical properties of indium tin oxide (ITO) films deposited at room temperature on glass and polyethylene terephthalate (PET) substrates were investigated. A clear evolution of optical transparency and sheet resistance with the content of H2 in the gas mixture of H2 and Ar during magnetron sputtering deposition is observed. An optimized performance of the transparent conductive properties ITO films on PET was achieved for samples prepared using H2/(Ar + H2) ratio in the range of 0.3-0.6%. Moreover, flexible ITO-PET samples show a better transparent conductive figure of merit, ΦTC = T10/RS, than their glass counterparts. These results provide valuable insight into the room temperature fabrication and development of transparent conductive ITO-based flexible devices.

  8. Chemical bath deposition growth and characterization of zinc oxide nanostructures on plain and platinum-coated glass substrates for hydrogen peroxide gas sensor application

    NASA Astrophysics Data System (ADS)

    Jamasali, Y. D. J.; Alguno, A. C.

    2015-06-01

    Growth of zinc oxide on plain and Pt-coated glass substrate via chemical bath deposition technique (CBD) were studied. Aqueous solutions of ammonium hydroxide (NH4OH) and zinc sulfate (ZnSO4) were used as the precursor substances in the synthesis. Ultraviolet-visible spectroscopy (UV-Vis) was performed to determine the energy band gap and X-ray diffraction (XRD) to examine crystallinity. Sensitivity measurements were carried out in order to examine its potential to be fabricated as hydrogen peroxide (H2O2) gas sensor. Experimental results in the sensitivity experiment show that in the presence of H2O2 gas, the resistance of ZnOincrease which can be used as the basis for H2O-2 detection. UV-Vis showed variation of energy band gap values but were all near the generally accepted value. XRD spectra further verify that ZnOwere indeed synthesized.

  9. High-power blue laser diodes with indium tin oxide cladding on semipolar (202{sup ¯}1{sup ¯}) GaN substrates

    SciTech Connect

    Pourhashemi, A. Farrell, R. M.; Cohen, D. A.; Speck, J. S.; DenBaars, S. P.; Nakamura, S.

    2015-03-16

    We demonstrate a high power blue laser diode (LD) using indium tin oxide as a cladding layer on semipolar oriented GaN. These devices show peak output powers and external quantum efficiencies comparable to state-of-the-art commercial c-plane devices. Ridge waveguide LDs were fabricated on (202{sup ¯}1{sup ¯}) oriented GaN substrates using InGaN waveguiding layers and GaN cladding layers. At a lasing wavelength of 451 nm at room temperature, an output power of 2.52 W and an external quantum efficiency of 39% were measured from a single facet under a pulsed injection current of 2.34 A. The measured differential quantum efficiency was 50%.

  10. Growth of well-aligned carbon nanotubes on a large area of Co Ni co-deposited silicon oxide substrate by thermal chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Lee, Cheol Jin; Park, Jeunghee; Kang, Seung Youl; Lee, Jin Ho

    2000-06-01

    We have grown vertically well-aligned multiwalled carbon nanotubes (CNT) on a large area of cobalt-nickel (Co-Ni) co-deposited silicon oxide substrate by thermal chemical vapor deposition using C 2H 2 gas, at 950°C. The diameter of CNTs is in the range of 50-120 nm and the length is about 130 μm. The grown CNTs have a bamboo structure and closed tip with no catalytic particles inside. As the particle size of Co-Ni catalyst decreases, the vertical alignment is enhanced. The CNTs exhibits a low turn-on voltage of 0.8 V/μm with an emission current density of 0.1 μA cm -2.

  11. A Comparative Study of Co-electrodeposited Cu2ZnSnS4 Absorber Material on Fluorinated Tin Oxide and Molybdenum Substrates

    NASA Astrophysics Data System (ADS)

    Sarswat, Prashant K.; Free, Michael L.

    2012-08-01

    A comparative study of electrochemically grown Cu2ZnSnS4 (CZTS) thin films on transparent conducting fluorinated tin oxide (FTO) electrodes and molybdenum-coated substrates was conducted. CZTS on FTO is highly desirable for bifacial-semitransparent photovoltaic applications for next-generation, environmentally friendly, high-efficiency solar panels. CZTS films were synthesized using single-stage electrochemical deposition followed by sulfur diffusion. Detailed comparisons of structural, morphological, electrochemical, and optical properties were performed using several techniques including Raman and ultraviolet-visible spectroscopy, atomic force microscopy, scanning electron microscopy, and photoelectrochemical characterization. All of the characterization experiments indicated that there is sufficient potential for electrochemically grown CZTS on FTO-coated glass as an alternative to CZTS on molybdenum-coated glass.

  12. Photoelectrochemical characteristics of TiO2 nanorod arrays grown on fluorine doped tin oxide substrates by the facile seeding layer assisted hydrothermal method

    NASA Astrophysics Data System (ADS)

    Sui, Mei-rong; Han, Cui-ping; Gu, Xiu-quan; Wang, Yong; Tang, Lu; Tang, Hui

    2016-05-01

    TiO2 nanorod arrays (NRAs) were prepared on fluorine doped tin oxide (FTO) substrates by a facile two-step hydrothermal method. The nanorods were selectively grown on the FTO regions which were covered with TiO2 seeding layer. It took 5 h to obtain the compact arrays with the nanorod length of ~2 μm and diameter of ~50 nm. The photoelectrochemical (PEC) properties of TiO2 NRAs are also investigated. It is demonstrated that the TiO2 NRAs indicate the good photoelectric conversion ability with an efficiency of 0.22% at a full-wavelength irradiation. A photocurrent density of 0.21 mA/cm2 is observed at 0.7 V versus the saturated calomel electrode (SCE). More evidences suggest that the charge transferring resistance is lowered at an irradiation, while the flat-band potential ( V fb) is shifted towards the positive side.

  13. Influence of the gas flow of Argon and the distance between substrate and plasma on properties of Al-doped zinc oxide films

    NASA Astrophysics Data System (ADS)

    Jiang, Y. J.; Zhang, D. X.; Cai, H. K.; Tao, K.; Xue, Y.; Sui, Y. P.; Wang, L. S.; Zhao, J. F.; Wang, J.

    2009-03-01

    Al-doped ZnO(ZAO) films were deposited by DC magnetron sputtering using facing zinc oxide targets at room temperature and in argon atmosphere. The effects of the gas flow of Argon and the distance between substrate and plasma on the properties of the ZAO thin films were characterized by several techniques. By optimizing the craft of preparation, the electrical resistivity as low as 3.3×10-4 Ω·cm and the optical transmittance over 80% in the visible range were obtained for these thin ZAO films. Therefore, the ZAO thin films were suitable for the window layers of n-i-p thin film solar cells or transparent conductive films.

  14. Anodization control for barrier-oxide thinning and 3D interconnected pores and direct electrodeposition of nanowire networks on native aluminium substrates.

    PubMed

    Gillette, Eleanor; Wittenberg, Stefanie; Graham, Lauren; Lee, Kwijong; Rubloff, Gary; Banerjee, Parag; Lee, Sang Bok

    2015-02-01

    Here we report a strategy for combining techniques for pore branching and barrier layer thinning to produce 3D porous anodized aluminum oxide films with direct ohmic contact to the native aluminum. This method provides an example of a rationally designed template which need not be removed from the aluminum, but which is also not constrained to traditional 2D pore geometry. We first demonstrate the barrier layer removal and pore branching techniques independently, and then combine them to produce free standing arrays of interconnected Ni nanostructures. Nickel nanostructures are deposited directly onto the aluminum to demonstrate the success of the structural modification, and showcase the potential for these films to be used as templates. This approach is the first to demonstrate the design and execution of multiple pore modification techniques in the same membrane, and demonstrates the first directly deposited 3D structures on aluminum substrates. PMID:25562070

  15. Nitrification in a zeoponic substrate

    NASA Technical Reports Server (NTRS)

    McGilloway, R. L.; Weaver, R. W.; Ming, D. W.; Gruener, J. E.

    2003-01-01

    Clinoptilolite is a zeolite mineral with high cation exchange capacity used in zeoponic substrates that have been proposed as a solid medium for growing plants or as a fertilizer material. The kinetics of nitrification has not been measured for NH4+ saturated zeoponic substrate. Experiments were conducted to evaluate the production of NO2- and NO3-, and nitrifier populations in zeoponic substrates. Small columns were filled with zeoponic substrate inoculated with a commercial inoculum or soil enrichment culture of nitrifying bacteria. In addition to column studies, a growth chamber study was conducted to evaluate the kinetics of nitrification in zeoponic substrates used to grow radishes (Raphanus sativus L.). The zeoponic substrate provided a readily available source of NH4+, and nitrifying bacteria were active in the substrate. Ammonium oxidation rates in column studies ranged from 5 to 10 micrograms N g-1 substrate h-1, and NO2- oxidation rates were 2 to 9.5 micrograms N g-1 substrate h-1. Rates determined from the growth chamber study were approximately 1.2 micrograms N g-1 substrate h-1. Quantities of NH4+ oxidized to NO2- and NO3- in inoculated zeoponic substrate were in excess of plant up-take. Acidification as a result of NH4+ oxidation resulted in a pH decline, and the zeoponic substrate showed limited buffering capacity.

  16. Neural Correlates of Appetitive-Aversive Interactions in Pavlovian Fear Conditioning

    ERIC Educational Resources Information Center

    Nasser, Helen M.; McNally, Gavan P.

    2013-01-01

    We used Pavlovian counterconditioning in rats to identify the neural mechanisms for appetitive-aversive motivational interactions. In Stage I, rats were trained on conditioned stimulus (CS)-food (unconditioned stimulus [US]) pairings. In Stage II, this appetitive CS was transformed into a fear CS via pairings with footshock. The development of…

  17. Appetite-Focused Cognitive-Behavioral Therapy in the Treatment of Binge Eating with Purging

    ERIC Educational Resources Information Center

    Dicker, Stacy L.; Craighead, Linda Wilcoxon

    2004-01-01

    The first-line treatment for bulimia nervosa (BN), cognitive-behavioral therapy (CBT), uses food-based self-monitoring. Six young women presenting with BN or significant purging behavior were treated with a modification, Appetite-Focused CBT (CBT-AF), in which self-monitoring is based on appetite cues and food monitoring is proscribed. This change…

  18. Appetitive but Not Aversive Olfactory Conditioning Modifies Antennal Movements in Honeybees

    ERIC Educational Resources Information Center

    Cholé, Hanna; Junca, Pierre; Sandoz, Jean-Christophe

    2015-01-01

    In honeybees, two olfactory conditioning protocols allow the study of appetitive and aversive Pavlovian associations. Appetitive conditioning of the proboscis extension response (PER) involves associating an odor, the conditioned stimulus (CS) with a sucrose solution, the unconditioned stimulus (US). Conversely, aversive conditioning of the sting…

  19. Khat use and appetite: An overview and comparison of amphetamine, khat and cathinone

    PubMed Central

    Lemieux, Andrine M.; Li, Bingshuo; al’Absi, Mustafa

    2014-01-01

    Ethnopharmacological relevance To understand the role of khat (Catha edulis) use on the aberrations in appetite and weight which are common comorbidities for khat and other amphetamine users. Materials and methods We provide a comprehensive overview and conceptual summary of the historical cultural use of khat as a natural stimulant and describe the similarities and differences between cathinone (the main psychoactive constituent of khat) and amphetamine highlighting the limited literature on the neurophysiology of appetite and subsequent weight effects of khat. Results Animal and some human studies indicate that khat produces appetite suppression, although little is known about mechanisms of this effect. Both direct and indirect effects of khat stem from multiple factors including behavioral, chemical and neurophysiological effects on appetite and metabolism. Classic and newly identified appetite hormones have not been explored sufficiently in the study of appetite and khat use. Unique methodological challenges and opportunities are encountered when examining effects of khat and cathinone including khat-specific medical comorbidities, unique route of administration, differential patterns of behavioral effects relative to amphetamines and the nascent state of our understanding of the neurobiology of this drug. Conclusion A considerable amount of work remains in the study of the appetite effects of khat chewing and outline a program of research that could inform our understanding of this natural amphetamine’s appetite effects and help prepare health care workers for the unique health effects of this drug. PMID:25435289

  20. AMPK Activation through Mitochondrial Regulation Results in Increased Substrate Oxidation and Improved Metabolic Parameters in Models of Diabetes

    PubMed Central

    Foretz, Marc; Li, Wei; Nguyen, Henry; Li, Yingwu; Pan, Alison; Uy, Gerald; Gross, Lisa; Baltgalvis, Kristen; Yung, Stephanie L.; Gururaja, Tarikere; Kinoshita, Taisei; Owyang, Alexander; Smith, Ira J.; McCaughey, Kelly; White, Kathy; Godinez, Guillermo; Alcantara, Raniel; Choy, Carmen; Ren, Hong; Basile, Rachel; Sweeny, David J.; Xu, Xiang; Issakani, Sarkiz D.; Carroll, David C.; Goff, Dane A.; Shaw, Simon J.; Singh, Rajinder; Boros, Laszlo G.; Laplante, Marc-André; Marcotte, Bruno; Kohen, Rita; Viollet, Benoit; Marette, André; Payan, Donald G.; Kinsella, Todd M.; Hitoshi, Yasumichi

    2013-01-01

    Modulation of mitochondrial function through inhibiting respiratory complex I activates a key sensor of cellular energy status, the 5'-AMP-activated protein kinase (AMPK). Activation of AMPK results in the mobilization of nutrient uptake and catabolism for mitochondrial ATP generation to restore energy homeostasis. How these nutrient pathways are affected in the presence of a potent modulator of mitochondrial function and the role of AMPK activation in these effects remain unclear. We have identified a molecule, named R419, that activates AMPK in vitro via complex I inhibition at much lower concentrations than metformin (IC50 100 nM vs 27 mM, respectively). R419 potently increased myocyte glucose uptake that was dependent on AMPK activation, while its ability to suppress hepatic glucose production in vitro was not. In addition, R419 treatment of mouse primary hepatocytes increased fatty acid oxidation and inhibited lipogenesis in an AMPK-dependent fashion. We have performed an extensive metabolic characterization of its effects in the db/db mouse diabetes model. In vivo metabolite profiling of R419-treated db/db mice showed a clear upregulation of fatty acid oxidation and catabolism of branched chain amino acids. Additionally, analyses performed using both 13C-palmitate and 13C-glucose tracers revealed that R419 induces complete oxidation of both glucose and palmitate to CO2 in skeletal muscle, liver, and adipose tissue, confirming that the compound increases mitochondrial function in vivo. Taken together, our results show that R419 is a potent inhibitor of complex I and modulates mitochondrial function in vitro and in diabetic animals in vivo. R419 may serve as a valuable molecular tool for investigating the impact of modulating mitochondrial function on nutrient metabolism in multiple tissues and on glucose and lipid homeostasis in diabetic animal models. PMID:24339975

  1. Energy expenditure, substrate oxidation, and body composition in subjects with chronic alcoholism: new findings from metabolic assessment.

    PubMed

    Addolorato, G; Capristo, E; Greco, A V; Stefanini, G F; Gasbarrini, G

    1997-09-01

    There is some controversy as to the effect of ethanol on body weight and alcohol energy contribution to body mass. The aim of this study was to evaluate the effect of alcohol addiction on resting energy expenditure (REE) and body composition. Twelve patients with current alcoholism (A) without severe liver disease or lipid and carbohydrate malabsorption were compared with a group of healthy social drinkers (B) matched for sex, age, and height. Their caloric intake was computed on the basis of a food diary. REE was measured with indirect calorimetry, and body composition was assessed by both anthropometry and bioimpedance. A significant decrease in fat mass in A compared with B was found (14.8 +/- 5.39 vs. 19.0 +/- 3.50 kg; p < 0.05). No significant differences were observed in fat-free mass (FFM) or in total body water between the two groups. A showed higher REE values normalized by FFM than B (35.5 +/- 2.97 vs. 33.0 +/- 2.95 kcal/kgFFM; p < 0.05). The nonprotein respiratory quotient was significantly lower in A than in B (0.76 +/- 0.03 vs. 0.86 +/- 0.03; p < 0.001), and A showed significantly higher lipid oxidation and lower carbohydrate oxidation than B (p < 0.05). The daily caloric intake provided only by food ingestion was found to be significantly higher in controls, but because the percentage of alcohol calories of total energy intake was 46.3 +/- 6.80 in alcoholics and 13.6 +/- 3.59 in controls (p < 0.0001), the total caloric intake, computed as food intake plus alcohol intake, was higher in alcoholics than in control subjects. No statistical differences were found in urinary nitrogen excretion and fecal loss between groups. Patients with alcoholism showed an increased REE over predicted values and a preferential lipid oxidation with respect to controls; these findings could be related to induction of microsomal ethanol oxidizing system and to mitochondrial function adaptation secondary to chronic alcohol abuse. In either case, the effects of such changes in

  2. A New Family of Membrane Electron Transporters and Its Substrates, Including a New Cell Envelope Peroxiredoxin, Reveal a Broadened Reductive Capacity of the Oxidative Bacterial Cell Envelope

    PubMed Central

    Cho, Seung-Hyun; Parsonage, Derek; Thurston, Casey; Dutton, Rachel J.; Poole, Leslie B.; Collet, Jean-Francois; Beckwith, Jon

    2012-01-01

    ABSTRACT The Escherichia coli membrane protein DsbD functions as an electron hub that dispatches electrons received from the cytoplasmic thioredoxin system to periplasmic oxidoreductases involved in protein disulfide isomerization, cytochrome c biogenesis, and sulfenic acid reduction. Here, we describe a new class of DsbD proteins, named ScsB, whose members are found in proteobacteria and Chlamydia. ScsB has a domain organization similar to that of DsbD, but its amino-terminal domain differs significantly. In DsbD, this domain directly interacts with substrates to reduce them, which suggests that ScsB acts on a different array of substrates. Using Caulobacter crescentus as a model organism, we searched for the substrates of ScsB. We discovered that ScsB provides electrons to the first peroxide reduction pathway identified in the bacterial cell envelope. The reduction pathway comprises a thioredoxin-like protein, TlpA, and a peroxiredoxin, PprX. We show that PprX is a thiol-dependent peroxidase that efficiently reduces both hydrogen peroxide and organic peroxides. Moreover, we identified two additional proteins that depend on ScsB for reduction, a peroxiredoxin-like protein, PrxL, and a novel protein disulfide isomerase, ScsC. Altogether, our results reveal that the array of proteins involved in reductive pathways in the oxidative cell envelope is significantly broader than was previously thought. Moreover, the identification of a new periplasmic peroxiredoxin indicates that in some bacteria, it is important to directly scavenge peroxides in the cell envelope even before they reach the cytoplasm. PMID:22493033

  3. Growth of Sputtered-Aluminum Oxide Thin Films on si (100) and si (111) Substrates with Al2O3 Buffer Layer

    NASA Astrophysics Data System (ADS)

    Lim, Wei Qiang; Shanmugan, Subramani; Devarajan, Mutharasu

    2016-03-01

    Aluminum oxide (Al2O3) thin films with Al2O3 buffer layer were deposited on Si (100) and Si (111) substrates using RF magnetron sputtering of Al2O3 target in Ar atmosphere. The synthesized films were then annealed at the temperature of 400∘C, 600∘C and 800∘C in nitrogen (N2) environment for 6h. Structural properties and surface morphology are examined by using X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM) and Atomic Force Microscope (AFM). XRD analysis indicated that different orientation of Al2O3 were formed with different intensities due to increase in the annealing temperature. From FESEM cross-section analysis results, it is observed that the thickness of films were increased as the annealing temperature increased. EDX analysis shows that the concentration of aluminum and oxygen on both the Si substrates increased with the increase in annealing temperature. The surface roughness of the films were found to be decreased first when the annealing temperature is increased to 400∘C, yet the roughness increased when the annealing temperature is further increased to 800∘C.

  4. Direct growth of NiCo2O4 nanostructures on conductive substrates with enhanced electrocatalytic activity and stability for methanol oxidation.

    PubMed

    Qian, Lei; Gu, Li; Yang, Li; Yuan, Hongyan; Xiao, Dan

    2013-08-21

    In this report, NiCo2O4 nanostructures with different morphologies were directly grown on conductive substrates (stainless steel and ITO) by a facile electrodeposition method in addition to a post-annealing process. The morphology changes on different conductive substrates are discussed in detail. The NiCo2O4 on stainless steel (SS) had a high surface area (119 m(2) g(-1)) and was successfully used in the electrocatalytic oxidation of methanol. The electrocatalytic performance was investigated by cyclic voltammetry (CV), chronoamperometry and electrochemical impedance spectroscopy (EIS) measurements. Impressively, the NiCo2O4 showed much higher electrocatalytic activity, lower overpotential and greater stability compared to that of only NiO or Co3O4 synthesized by the same method. The higher electrocatalytic activity is due to the high electron conductivity, large surface area of NiCo2O4 and the fast ion/electron transport in the electrode and at the electrolyte-electrode interface. This is important for further development of high performance non-platinum electrocatalysts for application in direct methanol fuel cells. PMID:23828628

  5. Chemical synthesis, characterisation, and biocompatibility of nanometre scale porous anodic aluminium oxide membranes for use as a cell culture substrate for the vero cell line: a preliminary study.

    PubMed

    Poinern, Gérrard Eddy Jai; Le, Xuan Thi; O'Dea, Mark; Becker, Thomas; Fawcett, Derek

    2014-01-01

    In this preliminary study we investigate for the first time the biomedical potential of using porous anodic aluminium oxide (AAO) membranes as a cell substrate for culturing the Cercopithecus aethiops (African green monkey) Kidney (Vero) epithelial cell line. One advantage of using the inorganic AAO membrane is the presence of nanometre scale pore channels that allow the exchange of molecules and nutrients across the membrane. The size of the pore channels can be preselected by adjusting the controlling parameters of a temperature controlled two-step anodization process. The cellular interaction and response of the Vero cell line with an in-house synthesised AAO membrane, a commercially available membrane, and a glass control were assessed by investigating cell adhesion, morphology, and proliferation over a 72 h period. The number of viable cells proliferating over the respective membrane surfaces revealed that the locally produced in-house AAO membrane had cells numbers similar to the glass control. The study revealed evidence of focal adhesion sites over the surface of the nanoporous membranes and the penetration of cellular extensions into the pore structure as well. The outcome of the study has revealed that nanometre scale porous AAO membranes have the potential to become practical cell culture scaffold substrates with the capability to enhance adhesion and proliferation of Vero cells. PMID:24579077

  6. Chemical Synthesis, Characterisation, and Biocompatibility of Nanometre Scale Porous Anodic Aluminium Oxide Membranes for Use as a Cell Culture Substrate for the Vero Cell Line: A Preliminary Study

    PubMed Central

    Poinern, Gérrard Eddy Jai; Le, Xuan Thi; Becker, Thomas; Fawcett, Derek

    2014-01-01

    In this preliminary study we investigate for the first time the biomedical potential of using porous anodic aluminium oxide (AAO) membranes as a cell substrate for culturing the Cercopithecus aethiops (African green monkey) Kidney (Vero) epithelial cell line. One advantage of using the inorganic AAO membrane is the presence of nanometre scale pore channels that allow the exchange of molecules and nutrients across the membrane. The size of the pore channels can be preselected by adjusting the controlling parameters of a temperature controlled two-step anodization process. The cellular interaction and response of the Vero cell line with an in-house synthesised AAO membrane, a commercially available membrane, and a glass control were assessed by investigating cell adhesion, morphology, and proliferation over a 72 h period. The number of viable cells proliferating over the respective membrane surfaces revealed that the locally produced in-house AAO membrane had cells numbers similar to the glass control. The study revealed evidence of focal adhesion sites over the surface of the nanoporous membranes and the penetration of cellular extensions into the pore structure as well. The outcome of the study has revealed that nanometre scale porous AAO membranes have the potential to become practical cell culture scaffold substrates with the capability to enhance adhesion and proliferation of Vero cells. PMID:24579077

  7. The role of the substrate on the dispersion in accumulation in III-V compound semiconductor based metal-oxide-semiconductor gate stacks

    NASA Astrophysics Data System (ADS)

    Krylov, Igor; Ritter, Dan; Eizenberg, Moshe

    2015-09-01

    Dispersion in accumulation is a widely observed phenomenon in metal-oxide-semiconductor gate stacks based on III-V compound semiconductors. The physical origin of this phenomenon is attributed to border traps located in the dielectric material adjacent to the semiconductor. Here, we study the role of the semiconductor substrate on the electrical quality of the first layers at atomic layer deposited (ALD) dielectrics. For this purpose, either Al2O3 or HfO2 dielectrics with variable thicknesses were deposited simultaneously on two technology important semiconductors—InGaAs and InP. Significantly larger dispersion was observed in InP based gate stacks compared to those based on InGaAs. The observed difference is attributed to a higher border trap density in dielectrics deposited on InP compared to those deposited on InGaAs. We therefore conclude that the substrate plays an important role in the determination of the electrical quality of the first dielectric monolayers deposited by ALD. An additional observation is that larger dispersion was obtained in HfO2 based capacitors compared to Al2O3 based capacitors, deposited on the same semiconductor. This phenomenon is attributed to the lower conduction band offset rather than to a higher border trap density.

  8. The role of the substrate on the dispersion in accumulation in III-V compound semiconductor based metal-oxide-semiconductor gate stacks

    SciTech Connect

    Krylov, Igor; Ritter, Dan; Eizenberg, Moshe

    2015-09-07

    Dispersion in accumulation is a widely observed phenomenon in metal-oxide-semiconductor gate stacks based on III-V compound semiconductors. The physical origin of this phenomenon is attributed to border traps located in the dielectric material adjacent to the semiconductor. Here, we study the role of the semiconductor substrate on the electrical quality of the first layers at atomic layer deposited (ALD) dielectrics. For this purpose, either Al{sub 2}O{sub 3} or HfO{sub 2} dielectrics with variable thicknesses were deposited simultaneously on two technology important semiconductors—InGaAs and InP. Significantly larger dispersion was observed in InP based gate stacks compared to those based on InGaAs. The observed difference is attributed to a higher border trap density in dielectrics deposited on InP compared to those deposited on InGaAs. We therefore conclude that the substrate plays an important role in the determination of the electrical quality of the first dielectric monolayers deposited by ALD. An additional observation is that larger dispersion was obtained in HfO{sub 2} based capacitors compared to Al{sub 2}O{sub 3} based capacitors, deposited on the same semiconductor. This phenomenon is attributed to the lower conduction band offset rather than to a higher border trap density.

  9. Effect of γ-Aminobutyric Acid (GABA) Producing Bacteria on In vitro Rumen Fermentation, Biogenic Amine Production and Anti-oxidation Using Corn Meal as Substrate

    PubMed Central

    Ku, Bum Seung; Mamuad, Lovelia L.; Kim, Seon-Ho; Jeong, Chang Dae; Soriano, Alvin P.; Lee, Ho-Il; Nam, Ki-Chang; Ha, Jong K.; Lee, Sang Suk

    2013-01-01

    The effects and significance of γ-amino butyric acid (GABA) producing bacteria (GPB) on in vitro rumen fermentation and reduction of biogenic amines (histamine, methylamine, ethylamine, and tyramine) using corn meal as a substrate were determined. Ruminal samples collected from ruminally fistulated Holstein cows served as inoculum and corn was used as substrate at 2% dry matter (DM). Different inclusion rates of GPB and GABA were evaluated. After incubation, addition of GPB had no significant effect on in vitro fermentation pH and total gas production, but significantly increased the ammonia nitrogen (NH3-N) concentration and reduced the total biogenic amines production (p<0.05). Furthermore, antioxidation activity was improved as indicated by the significantly higher concentration of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) among treated samples when compared to the control (p<0.05). Additionally, 0.2% GPB was established as the optimum inclusion level. Taken together, these results suggest the potential of utilizing GPB as feed additives to improve growth performance in ruminants by reducing biogenic amines and increasing anti-oxidation. PMID:25049853

  10. Breakfast Macronutrient Composition Influences Thermic Effect of Feeding and Fat Oxidation in Young Women Who Habitually Skip Breakfast

    PubMed Central

    Neumann, Brianna L.; Dunn, Amy; Johnson, Dallas; Adams, J. D.; Baum, Jamie I.

    2016-01-01

    The purpose of this study was to determine if breakfast macronutrient composition improved thermic effect of feeding (TEF) and appetite after a one-week adaptation in young women who habitually skip breakfast. A randomized, controlled study was conducted in females (24.1 ± 2 years), who skip breakfast (≥5 times/week). Participants were placed into one of three groups for eight days (n = 8 per group): breakfast skipping (SKP; no breakfast), carbohydrate (CHO; 351 kcal; 59 g CHO, 10 g PRO, 8 g fat) or protein (PRO; 350 kcal; 39 g CHO, 30 g PRO, 8 g fat). On days 1 (D1) and 8 (D8), TEF, substrate oxidation, appetite and blood glucose were measured. PRO had higher (p < 0.05) TEF compared to SKP and CHO on D1 and D8, with PRO having 29% higher TEF than CHO on D8. On D1, PRO had 30.6% higher fat oxidation than CHO and on D8, PRO had 40.6% higher fat oxidation than CHO. SKP had higher (p < 0.05) fat oxidation on D1 and D8 compared to PRO and CHO. There was an interaction (p < 0.0001) of time and breakfast on appetite response. In addition, CHO had a significant increase (p < 0.05) in PP hunger response on D8 vs. D1. CHO and PRO had similar PP (postprandial) glucose responses on D1 and D8. Consumption of PRO breakfast for 8 days increased TEF compared to CHO and SKP, while consumption of CHO for one week increased PP hunger response. PMID:27517958

  11. Breakfast Macronutrient Composition Influences Thermic Effect of Feeding and Fat Oxidation in Young Women Who Habitually Skip Breakfast.

    PubMed

    Neumann, Brianna L; Dunn, Amy; Johnson, Dallas; Adams, J D; Baum, Jamie I

    2016-01-01

    The purpose of this study was to determine if breakfast macronutrient composition improved thermic effect of feeding (TEF) and appetite after a one-week adaptation in young women who habitually skip breakfast. A randomized, controlled study was conducted in females (24.1 ± 2 years), who skip breakfast (≥5 times/week). Participants were placed into one of three groups for eight days (n = 8 per group): breakfast skipping (SKP; no breakfast), carbohydrate (CHO; 351 kcal; 59 g CHO, 10 g PRO, 8 g fat) or protein (PRO; 350 kcal; 39 g CHO, 30 g PRO, 8 g fat). On days 1 (D1) and 8 (D8), TEF, substrate oxidation, appetite and blood glucose were measured. PRO had higher (p < 0.05) TEF compared to SKP and CHO on D1 and D8, with PRO having 29% higher TEF than CHO on D8. On D1, PRO had 30.6% higher fat oxidation than CHO and on D8, PRO had 40.6% higher fat oxidation than CHO. SKP had higher (p < 0.05) fat oxidation on D1 and D8 compared to PRO and CHO. There was an interaction (p < 0.0001) of time and breakfast on appetite response. In addition, CHO had a significant increase (p < 0.05) in PP hunger response on D8 vs. D1. CHO and PRO had similar PP (postprandial) glucose responses on D1 and D8. Consumption of PRO breakfast for 8 days increased TEF compared to CHO and SKP, while consumption of CHO for one week increased PP hunger response. PMID:27517958

  12. Metal oxide nanostructures synthesized on flexible and solid substrates and used for catalysts, UV detectors, and chemical sensors

    NASA Astrophysics Data System (ADS)

    Willander, Magnus; Sadollahkhani, Azar; Echresh, Ahmad; Nur, Omer

    2014-03-01

    In this paper we demonstrate the visibility of the low temperature chemical synthesis for developing device quality material grown on flexible and solid substrates. Both colorimetric sensors and UV photodetectors will be presented. The colorimetric sensors developed on paper were demonstrated for heavy metal detection, in particular for detecting copper ions in aqueous solutions. The demonstrated colorimetric copper ion sensors developed here are based on ZnO@ZnS core-shell nanoparticles (CSNPs). These sensors demonstrated an excellent low detection limit of less than 1 ppm of copper ions. Further the colorimetric sensors operate efficiently in a wide pH range between 4 and 11, and even in turbulent water. The CSNPs were additionally used as efficient photocatalytic degradation element and were found to be more efficient than pure ZnO nanoparticles (NPs). Also p-NiO/n-ZnO thin film/nanorods pn junctions were synthesized by a two-step synthesis process and were found to act as efficient UV photodetectors. Additionally we show the effect of the morphology of different CuO nanostructures on the efficiency of photo catalytic degradation of Congo red organic dye.

  13. Growth and characterization of ZnO/ZnTe core/shell nanowire arrays on transparent conducting oxide glass substrates

    PubMed Central

    2012-01-01

    We report the growth and characterization of ZnO/ZnTe core/shell nanowire arrays on indium tin oxide. Coating of the ZnTe layer on well-aligned vertical ZnO nanowires has been demonstrated by scanning electron microscope, tunneling electron microscope, X-ray diffraction pattern, photoluminescence, and transmission studies. The ZnO/ZnTe core/shell nanowire arrays were then used as the active layer and carrier transport medium to fabricate a photovoltaic device. The enhanced photocurrent and faster response observed in ZnO/ZnTe, together with the quenching of the UV emission in the PL spectra, indicate that carrier separation in this structure plays an important role in determining their optical response. The results also indicate that core/shell structures can be made into useful photovoltaic devices. PMID:22804871

  14. Efficient polymer solar cells fabricated on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)-etched old indium tin oxide substrates.

    PubMed

    Elshobaki, Moneim; Anderegg, James; Chaudhary, Sumit

    2014-08-13

    In organic electronic devices, indium tin oxide (ITO) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) are the most common transparent electrode and anodic buffer layer materials, respectively. A widespread concern is that PEDOT:PSS is acidic and etches ITO. We show that this issue is not serious: only a few nanometers of ITO are etched in typical device processing conditions and storage thereafter; conductivity losses are affordable; and optical transmission gains further offset these losses. Organic photovoltaic (OPV) devices fabricated on old ITO (with PEDOT:PSS history) were similar or higher in efficiency than devices on fresh ITO. Poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl

  15. Efficient Polymer Solar Cells Fabricated on Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate)-Etched Old Indium Tin Oxide Substrates

    SciTech Connect

    Elshobaki, Moneim; Anderegg, James; Chaudhary, Sumit

    2014-08-13

    In organic electronic devices, indium tin oxide (ITO) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) are the most common transparent electrode and anodic buffer layer materials, respectively. A widespread concern is that PEDOT:PSS is acidic and etches ITO. We show that this issue is not serious: only a few nanometers of ITO are etched in typical device processing conditions and storage thereafter; conductivity losses are affordable; and optical transmission gains further offset these losses. Organic photovoltaic (OPV) devices fabricated on old ITO (with PEDOT:PSS history) were similar or higher in efficiency than devices on fresh ITO. Poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl

  16. Preparation of thin hexagonal highly-ordered anodic aluminum oxide (AAO) template onto silicon substrate and growth ZnO nanorod arrays by electrodeposition

    NASA Astrophysics Data System (ADS)

    Chahrour, Khaled M.; Ahmed, Naser M.; Hashim, M. R.; Elfadill, Nezar G.; Qaeed, M. A.; Bououdina, M.

    2014-12-01

    In this study, anodic aluminum oxide (AAO) templates of Aluminum thin films onto Ti-coated silicon substrates were prepared for growth of nanostructure materials. Hexagonally highly ordered thin AAO templates were fabricated under controllable conditions by using a two-step anodization. The obtained thin AAO templates were approximately 70 nm in pore diameter and 250 nm in length with 110 nm interpore distances within an area of 3 cm2. The difference between first and second anodization was investigated in details by in situ monitoring of current-time curve. A bottom barrier layer of the AAO templates was removed during dropping the voltage in the last period of the anodization process followed by a wet etching using phosphoric acid (5 wt%) for several minutes at ambient temperature. As an application, Zn nanorod arrays embedded in anodic alumina (AAO) template were fabricated by electrodeposition. Oxygen was used to oxidize the electrodeposited Zn nanorods in the AAO template at 700 °C. The morphology, structure and photoluminescence properties of ZnO/AAO assembly were analyzed using Field-emission scanning electron microscope (FESEM), Energy dispersive X-ray spectroscopy (EDX), Atomic force microscope (AFM), X-ray diffraction (XRD) and photoluminescence (PL).

  17. Fasting substrate oxidation in relation to habitual dietary fat intake and insulin resistance in non-diabetic women: a case for metabolic flexibility?

    PubMed Central

    2013-01-01

    Background Metabolic flexibility described as “the capacity of the body to match fuel oxidation to fuel availability” has been implicated in insulin resistance. We examined fasting substrate oxidation in relation to dietary macronutrient intake, and markers of insulin resistance in otherwise healthy women, with and without a family history of diabetes mellitus (FH DM). Methods We measured body composition (dual x-ray absorptiometry), visceral and subcutaneous adipose tissue area (VAT, SAT, using Computerised Tomography), fasting [glucose], [insulin], [free fatty acids], [blood lipids], insulin resistance (HOMA-IR), resting energy expenditure (REE), respiratory exchange ratio(RER) and self-reported physical activity in a convenience sample of 180 women (18-45 yrs). A food frequency questionnaire was used to assess energy intake (EI) and calculate the RER: Food Quotient (FQ) ratio. Only those with EI:REE (1.05 -2.28) were included (N=140). Insulin resistance was defined HOMA-IR (>1.95). Results The Insulin Resistant (IR) group had higher energy, carbohydrate and protein intakes (p < 0.05) and lower PA levels than Insulin Sensitive (IS) group (P < 0.001), but there were no differences in RER or RER:FQ between groups. However, nearly 50% of the variance in HOMA-IR was explained by age, body fat %, VAT, RER:FQ and FH DM (adjusted R2 = 0.50, p < 0.0001). Insulin-resistant women, and those with FH DM had a higher RER:FQ than their counterparts (p < 0.01), independent of body fat % or distribution. Conclusion In these apparently healthy, weight-stable women, insulin resistance and FH DM were associated with lower fat oxidation in relation to dietary fat intake, suggesting lower metabolic flexibility. PMID:23317295

  18. Dielectric, electro-optical, and photoluminescence characteristics of ferroelectric liquid crystals on a graphene-coated indium tin oxide substrate.

    PubMed

    Singh, Dharmendra Pratap; Gupta, Swadesh Kumar; Vimal, Tripti; Manohar, Rajiv

    2014-08-01

    Multilayer graphene was deposited on indium tin oxide (ITO) -coated glass plates and characterized by suitable techniques. A liquid crystal sample cell was designed using graphene deposited ITO glass plates without any additional treatment for alignment. Ferroelectric liquid crystal (FLC) material was filled in the sample cell. The effect of multilayer graphene on the characteristics of FLC material was investigated. The extremely high relative permittivity of pristine graphene and charge transfer between graphene and FLC material were consequences of the enormous increase in relative permittivity for the graphene-FLC (GFLC) system as compared to pure FLC. The presence of multilayer graphene suppresses the ionic impurities, comprised in the FLC material at lower frequencies. The ionic charge annihilation mechanism might be responsible for the reduction of ionic impurities. The presence of graphene reduces the net ferroelectricity and results in a change in the spontaneous polarization of pure FLC. Rotational viscosity of the GFLC system also decreases due to the strong π-π interaction between the FLC molecule and multilayer graphene. The photoluminescence of the GFLC system is blueshifted as compared to pure FLC, which is due to the coupling of energy released in the process of charge annihilation and photon emission. PMID:25215743

  19. Structure and Thermoelectric Properties of Te-Ag-Ge-Sb (TAGS) Materials Obtained by Reduction of Melted Oxide Substrates

    NASA Astrophysics Data System (ADS)

    Kusz, B.; Miruszewski, T.; Bochentyn, B.; Łapiński, M.; Karczewski, J.

    2016-02-01

    Ge0.77Ag0.1Sb0.13Te1 alloy was fabricated by a novel two-step route. Firstly, oxide reagents were melted at high temperature and quenched into pellets. The pellets were milled to powder and then reduced in hydrogen at various temperatures for various periods of time. Energy-dispersive x-ray analysis indicated the possibility of successful fabrication of stoichiometric thermoelectric materials from the Te-Ag-Ge-Sb system. The electrical conductivity and Seebeck coefficient have been determined over the temperature range from 20°C to 340°C in argon atmosphere. It was also shown that, for most of the fabricated samples, the crystallite size as well as electrical parameters such as the electrical conductivity, Seebeck coefficient, and figure of merit ( ZT) increased with increasing reduction time. The highest value of ZT (˜1.0 at 340°C) was obtained for samples reduced in hydrogen atmosphere at 400°C for 20 h and 40 h.

  20. Growth mechanism and optical properties of Ti thin films deposited onto fluorine-doped tin oxide glass substrate

    SciTech Connect

    Einollahzadeh-Samadi, Motahareh; Dariani, Reza S.

    2015-03-15

    In this work, a detailed study of the influence of the thickness on the morphological and optical properties of titanium (Ti) thin films deposited onto rough fluorine-doped tin oxide glass by d.c. magnetron sputtering is carried out. The films were characterized by several methods for composition, crystallinity, morphology, and optical properties. Regardless of the deposition time, all the studied Ti films of 400, 1500, 2000, and 2500 nm in thickness were single crystalline in the α-Ti phase and also very similar to each other with respect to composition. Using the atomic force microscopy (AFM) technique, the authors analyzed the roughness evolution of the Ti films characteristics as a function of the film thickness. By applying the dynamic scaling theory to the AFM images, a steady growth roughness exponent α = 0.72 ± 0.02 and a dynamic growth roughness exponent β = 0.22 ± 0.02 were determined. The value of α and β are consistent with nonlinear growth model incorporating random deposition with surface diffusion. Finally, measuring the reflection spectra of the samples by a spectrophotometer in the spectral range of 300–1100 nm allowed us to investigate the optical properties. The authors observed the increments of the reflection of Ti films with thickness, which by employing the effective medium approximation theory showed an increase in thickness followed by an increase in the volume fraction of metal.

  1. Timing of fat and liquid sugar intake alters substrate oxidation and food efficiency in male Wistar rats.

    PubMed

    Oosterman, Johanneke E; Foppen, Ewout; van der Spek, Rianne; Fliers, Eric; Kalsbeek, Andries; la Fleur, Susanne E

    2015-03-01

    In addition to the amount of ingested calories, both timing of food intake and meal composition are determinants of body weight gain. However, at present, it is unknown if the inappropriate timing of diet components is responsible for body weight gain. In the present study, we therefore studied a time-dependent effect of the diet composition on energy homeostasis. Male Wistar rats were subjected to chow ad libitum (chow group) or a choice diet with saturated fat, a 30% sugar solution, chow and tap water. The choice diet was provided either with all components ad libitum (AL), with ad libitum access to chow, tap water and a 30% sugar solution, but with access to saturated fat only during the light period (LF), or with ad libitum access to chow, tap water and saturated fat, but access to a 30% sugar solution only during the light period (LS). Caloric intake and body weight gain were monitored during 31 days. Energy expenditure was measured in the third week in calorimetric cages. All rats on a choice diet showed hyperphagia and gained more body weight compared to the chow group. Within the choice diet groups, rats on the LS diet were most food efficient (i.e. gained most body weight per ingested calorie) and showed a lower respiratory exchange ratio (RER) with an anti-phasic pattern, whereas no differences in locomotor activity or heat production were found. Collectively these data indicate that the timing of the diet composition affects food efficiency, most likely due to a shifted oxidation pattern, which can predispose for obesity. Further studies are underway to assess putative mechanisms involved in this dysregulation. PMID:25317718

  2. Kraft Pulp Biobleaching and Mediated Oxidation of a Nonphenolic Substrate by Laccase from Streptomyces cyaneus CECT 3335

    PubMed Central

    Arias, M. Enriqueta; Arenas, María; Rodríguez, Juana; Soliveri, Juan; Ball, Andrew S.; Hernández, Manuel

    2003-01-01

    A new laccase (EC 1.10.3.2) produced by Streptomyces cyaneus CECT 3335 in liquid media containing soya flour (20 g per liter) was purified to homogeneity. The physicochemical, catalytic, and spectral characteristics of this enzyme, as well as its suitability for biobleaching of eucalyptus kraft pulps, were assessed. The purified laccase had a molecular mass of 75 kDa and an isoelectric point of 5.6, and its optimal pH and temperature were 4.5 and 70°C, respectively. The activity was strongly enhanced in the presence of Cu2+, Mn2+, and Mg2+ and was completely inhibited by EDTA and sodium azide. The purified laccase exhibited high levels of activity against 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) and 2,6-dimethoxyphenol and no activity against tyrosine. The UV-visible spectrum of the purified laccase was the typical spectrum of the blue laccases, with an absorption peak at 600 nm and a shoulder around 330 to 340 nm. The ability of the purified laccase to oxidize a nonphenolic compound, such as veratryl alcohol, in the presence of ABTS opens up new possibilities for the use of bacterial laccases in the pulp and paper industry. We demonstrated that application of the laccase from S. cyaneus in the presence of ABTS to biobleaching of eucalyptus kraft pulps resulted in a significant decrease in the kappa number (2.3 U) and an important increase in the brightness (2.2%, as determined by the International Standard Organization test) of pulps, showing the suitability of laccases produced by streptomycetes for industrial purposes. PMID:12676669

  3. Effects of multivitamin-multimineral supplementation on appetite of stunted young Beninese children.

    PubMed

    Dossa, R A M; Ategbo, E A D; van Raaij, J M A; de Graaf, C; Hautvast, J G A J

    2002-10-01

    In the developing world, food intake of young children is often insufficient for growth. Reduced appetite due to several factors including micronutrient deficiencies might be an explanation. We hypothesized that a multivitamin-multimineral supplementation will improve appetite of stunted children in south of Benin. Multivitamin-multimineral supplements (VITALIA-tablets) contain 11 vitamins and 8 minerals. Stunted children (Ht/Age Z score < -2) of 17-32 months old were randomly assigned to multivitamin-multimineral (n = 48) or placebo (n = 53) group. Supplementation was daily and supervised throughout 6 weeks. Knee-heel length, length, weight, arm circumference and appetite were assessed once a week for the three weeks preceding and the three weeks following the six-week intervention period. Growth was additionally assessed 4 months after intervention. Each appetite test day, morbidity data and mother's report on child's appetite throughout the preceding day were recorded. Reported appetite, intake of test food and knee-heel length increased after supplementation in both groups (p < 0.05), but were not different between groups. Growth was similar 4 months after the intervention. Morbidity was comparable in both groups before as well as after supplementation. We conclude that 6-week multivitamin-multimineral supplementation alone failed to improve appetite and growth of stunted young children. PMID:12354679

  4. The Histaminergic Tuberomamillary Nucleus Is Involved in Appetite for Sex, Water and Amphetamine.

    PubMed

    Contreras, Marco; Riveros, María E; Quispe, Maricel; Sánchez, Cristián; Perdomo, Guayec; Torrealba, Fernando; Valdés, José L

    2016-01-01

    The histaminergic system is one component of the ascending arousal system which is involved in wakefulness, neuroendocrine control, cognition, psychiatric disorders and motivation. During the appetitive phase of motivated behaviors the arousal state rises to an optimal level, thus giving proper intensity to the behavior. Previous studies have demonstrated that the histaminergic neurons show an earlier activation during the appetitive phase of feeding, compared to other ascending arousal system nuclei, paralleled with a high increase in arousal state. Lesions restricted to the histaminergic neurons in rats reduced their motivation to get food even after 24 h of food deprivation, compared with intact or sham lesioned rats. Taken together, these findings indicate that the histaminergic system is important for appetitive behavior related to feeding. However, its role in other goal-directed behaviors remains unexplored. In the present work, male rats rendered motivated to obtain water, sex, or amphetamine showed an increase in Fos-ir of histaminergic neurons in appetitive behaviors directed to get those reinforcers. However, during appetitive tests to obtain sex, or drug in amphetamine-conditioned rats, Fos expression increased in most other ascending arousal system nuclei, including the orexin neurons in the lateral hypothalamus, dorsal raphe, locus coeruleus and laterodorsal tegmental neurons, but not in the ventral tegmental area, which showed no Fos-ir increase in any of the 3 conditions. Importantly, all these appetitive behaviors were drastically reduced after histaminergic cell-specific lesion, suggesting a critical contribution of histamine on the intensity component of several appetitive behaviors. PMID:26845170

  5. The Histaminergic Tuberomamillary Nucleus Is Involved in Appetite for Sex, Water and Amphetamine

    PubMed Central

    Perdomo, Guayec; Torrealba, Fernando; Valdés, José L.

    2016-01-01

    The histaminergic system is one component of the ascending arousal system which is involved in wakefulness, neuroendocrine control, cognition, psychiatric disorders and motivation. During the appetitive phase of motivated behaviors the arousal state rises to an optimal level, thus giving proper intensity to the behavior. Previous studies have demonstrated that the histaminergic neurons show an earlier activation during the appetitive phase of feeding, compared to other ascending arousal system nuclei, paralleled with a high increase in arousal state. Lesions restricted to the histaminergic neurons in rats reduced their motivation to get food even after 24h of food deprivation, compared with intact or sham lesioned rats. Taken together, these findings indicate that the histaminergic system is important for appetitive behavior related to feeding. However, its role in other goal-directed behaviors remains unexplored. In the present work, male rats rendered motivated to obtain water, sex, or amphetamine showed an increase in Fos-ir of histaminergic neurons in appetitive behaviors directed to get those reinforcers. However, during appetitive tests to obtain sex, or drug in amphetamine-conditioned rats, Fos expression increased in most other ascending arousal system nuclei, including the orexin neurons in the lateral hypothalamus, dorsal raphe, locus coeruleus and laterodorsal tegmental neurons, but not in the ventral tegmental area, which showed no Fos-ir increase in any of the 3 conditions. Importantly, all these appetitive behaviors were drastically reduced after histaminergic cell-specific lesion, suggesting a critical contribution of histamine on the intensity component of several appetitive behaviors. PMID:26845170

  6. Appetitive Aggression and Adverse Childhood Experiences Shape Violent Behavior in Females Formerly Associated with Combat.

    PubMed

    Augsburger, Mareike; Meyer-Parlapanis, Danie; Bambonye, Manassé; Elbert, Thomas; Crombach, Anselm

    2015-01-01

    This study investigated the impact of violent experiences during childhood, posttraumatic stress disorder (PTSD) and appetitive aggression on everyday violent behavior in Burundian females with varying participation in war. Moreover, group differences in trauma-related and aggression variables were expected. Appetitive aggression describes the perception of violence perpetration as fascinating and appealing and is a common phenomenon in former combatants. Semi-structured interviews were conducted with 158 females, either former combatants, supporters of armed forces or civilians during the civil war in Burundi. The PTSD Symptom Scale Interview was used to assess PTSD symptom severity, the Appetitive Aggression Scale to measure appetitive aggression and the Domestic and Community Violence Checklist to assess both childhood maltreatment and recent aggressive behavior. Former combatants had experienced more traumatic events, perpetrated more violence and reported higher levels of appetitive aggression than supporters and civilians. They also suffered more severely from PTSD symptoms than civilians but not than supporters. The groups did not differ regarding childhood maltreatment. Both appetitive aggression and childhood violence predicted ongoing aggressive behavior, whereas the latter outperformed PTSD symptom severity. These findings support current research showing that adverse childhood experiences and a positive attitude toward aggression serve as the basis for aggressive behavior and promote an ongoing cycle of violence in post-conflict regions. Female members of armed groups are in need of demobilization procedures including trauma-related care and interventions addressing appetitive aggression. PMID:26635666

  7. Appetitive Aggression and Adverse Childhood Experiences Shape Violent Behavior in Females Formerly Associated with Combat

    PubMed Central

    Augsburger, Mareike; Meyer-Parlapanis, Danie; Bambonye, Manassé; Elbert, Thomas; Crombach, Anselm

    2015-01-01

    This study investigated the impact of violent experiences during childhood, posttraumatic stress disorder (PTSD) and appetitive aggression on everyday violent behavior in Burundian females with varying participation in war. Moreover, group differences in trauma-related and aggression variables were expected. Appetitive aggression describes the perception of violence perpetration as fascinating and appealing and is a common phenomenon in former combatants. Semi-structured interviews were conducted with 158 females, either former combatants, supporters of armed forces or civilians during the civil war in Burundi. The PTSD Symptom Scale Interview was used to assess PTSD symptom severity, the Appetitive Aggression Scale to measure appetitive aggression and the Domestic and Community Violence Checklist to assess both childhood maltreatment and recent aggressive behavior. Former combatants had experienced more traumatic events, perpetrated more violence and reported higher levels of appetitive aggression than supporters and civilians. They also suffered more severely from PTSD symptoms than civilians but not than supporters. The groups did not differ regarding childhood maltreatment. Both appetitive aggression and childhood violence predicted ongoing aggressive behavior, whereas the latter outperformed PTSD symptom severity. These findings support current research showing that adverse childhood experiences and a positive attitude toward aggression serve as the basis for aggressive behavior and promote an ongoing cycle of violence in post-conflict regions. Female members of armed groups are in need of demobilization procedures including trauma-related care and interventions addressing appetitive aggression. PMID:26635666

  8. A hot-spot-active magnetic graphene oxide substrate for microRNA detection based on cascaded chemiluminescence resonance energy transfer

    NASA Astrophysics Data System (ADS)

    Bi, Sai; Chen, Min; Jia, Xiaoqiang; Dong, Ying

    2015-02-01

    Herein, a cascaded chemiluminescence resonance energy transfer (C-CRET) process was demonstrated from horseradish peroxidase (HRP)-mimicking DNAzyme-catalyzed luminol-H2O2 to fluorescein and further to graphene oxide (GO) when HRP-mimicking DNAzyme/fluorescein was in close proximity to the GO surface. The proposed C-CRET system was successfully implemented to construct three modes of C-CRET hot-spot-active substrates (modes I, II and III) by covalently immobilizing HRP-mimicking DNAzyme/fluorescein-labeled hairpin DNAs (hot-spot-generation probes) on magnetic GO (MGO), resulting in a signal ``off'' state due to the quenching of the luminol/H2O2/HRP-mimicking DNAzyme/fluorescein CRET system by GO. Upon the introduction of microRNA-122 (miRNA-122), the targets (mode I) or the new triggers that were generated through a strand displacement reaction (SDR) initiated by miRNA-122 (modes II and III) hybridized with the loop domains of hairpin probes on MGO to form double-stranded (modes I and II) or triplex-stem structures (mode III), causing an ``open'' configuration of the hairpin probe and a CRET signal ``on'' state, thus achieving sensitive and selective detection of miRNA-122. More importantly, the substrate exhibited excellent controllability, reversibility and reproducibility through SDR and magnetic separation (modes II and III), especially sequence-independence for hairpin probes in mode III, holding great potential for the development of a versatile platform for optical biosensing.Herein, a cascaded chemiluminescence resonance energy transfer (C-CRET) process was demonstrated from horseradish peroxidase (HRP)-mimicking DNAzyme-catalyzed luminol-H2O2 to fluorescein and further to graphene oxide (GO) when HRP-mimicking DNAzyme/fluorescein was in close proximity to the GO surface. The proposed C-CRET system was successfully implemented to construct three modes of C-CRET hot-spot-active substrates (modes I, II and III) by covalently immobilizing HRP-mimicking DNAzyme

  9. Predictors of posttraumatic stress and appetitive aggression in active soldiers and former combatants

    PubMed Central

    Nandi, Corina; Crombach, Anselm; Bambonye, Manassé; Elbert, Thomas; Weierstall, Roland

    2015-01-01

    Background During the period between 1993 and 2005, the people of Burundi were trapped within a violent civil war. In post-conflict regions, symptoms of posttraumatic stress disorder (PTSD) were found to be widespread. At the same time, combatants often reported having perceived committing violence as exciting and appealing, an experience referred to as appetitive aggression. Both of these phenomena hamper the building of a functional and peaceful society. Objective This study aims to investigate the factors that are associated with the level of PTSD and appetitive aggression in former and still active combatants. Methods Semi-structured interviews were conducted with 948 male Burundians: 556 active soldiers and 392 ex-combatants. PTSD symptom severity was assessed using the PTSD Symptom Scale Interview, while appetitive aggression was assessed using the Appetitive Aggression Scale. Results Linear regression analyses revealed that the number of traumatic events, childhood maltreatment, and their interaction predicted PTSD symptom severity, whereas self-committed violence did not. The number of traumatic events and self-committed violence were associated with appetitive aggression. Childhood maltreatment alone was not associated with appetitive aggression; however, its interaction with self-committed violence did predict appetitive aggression. When controlling for predictors, ex-combatants reported a higher degree of PTSD symptomatology, whereas active soldiers reported a higher degree of appetitive aggression. Conclusion We conclude that childhood maltreatment is an additional, significant risk factor that exacerbates the psychological consequences of violent conflicts. Self-committed violence may not necessarily engender trauma-related disorders, but is highly related to appetitive aggression. PMID:25908529

  10. Effects of exercise intensity on plasma concentrations of appetite-regulating hormones: Potential mechanisms.

    PubMed

    Hazell, Tom J; Islam, Hashim; Townsend, Logan K; Schmale, Matt S; Copeland, Jennifer L

    2016-03-01

    The physiological control of appetite regulation involves circulating hormones with orexigenic (appetite-stimulating) and anorexigenic (appetite-inhibiting) properties that induce alterations in energy intake via perceptions of hunger and satiety. As the effectiveness of exercise to induce weight loss is a controversial topic, there is considerable interest in the effect of exercise on the appetite-regulating hormones such as acylated ghrelin, peptide YY (PYY), glucagon-like peptide-1 (GLP-1), and pancreatic polypeptide (PP). Research to date suggests short-term appetite regulation following a single exercise session is likely affected by decreases in acylated ghrelin and increases in PYY, GLP-1, and PP. Further, this exercise-induced response may be intensity-dependent. In an effort to guide future research, it is important to consider how exercise alters the circulating concentrations of these appetite-regulating hormones. Potential mechanisms include blood redistribution, sympathetic nervous system activity, gastrointestinal motility, cytokine release, free fatty acid concentrations, lactate production, and changes in plasma glucose and insulin concentrations. This review of relevant research suggests blood redistribution during exercise may be important for suppressing ghrelin, while other mechanisms involving cytokine release, changes in plasma glucose and insulin concentrations, SNS activity, and muscle metabolism likely mediate changes in the anorexigenic signals PYY and GLP-1. Overall, changes in appetite-regulating hormones following acute exercise appear to be intensity-dependent, with increasing intensity leading to a greater suppression of orexigenic signals and greater stimulation of anorexigenic signals. However, there is less research on how exercise-induced responses in appetite-regulating hormones differ between sexes or different age groups. A better understanding of how exercise intensity and workload affect appetite across the sexes and life

  11. Identifying the Elusive Sites of Tyrosyl Radicals in Cytochrome c Peroxidase: Implications for Oxidation of Substrates Bound at a Site Remote from the Heme

    PubMed Central

    2015-01-01

    The location of the Trp radical and the catalytic function of the [Fe(IV)=O Trp191•+] intermediate in cytochrome c peroxidase (CcP) are well-established; however, the unambiguous identification of the site(s) for the formation of tyrosyl radical(s) and their possible biological roles remain elusive. We have now performed a systematic investigation of the location and reactivity of the Tyr radical(s) using multifrequency Electron Paramagnetic Resonance (EPR) spectroscopy combined with multiple-site Trp/Tyr mutations in CcP. Two tyrosines, Tyr71 and Tyr236, were identified as those contributing primarily to the EPR spectrum of the tyrosyl radical, recorded at 9 and 285 GHz. The EPR characterization also showed that the heme distal-side Trp51 is involved in the intramolecular electron transfer between Tyr71 and the heme and that formation of Tyr71• and Tyr236• is independent of the [Fe(IV)=O Trp191•+] intermediate. Tyr71 is located in an optimal position to mediate the oxidation of substrates binding at a site, more than 20 Å from the heme, which has been reported recently in the crystal structures of CcP with bound guaicol and phenol [Murphy, E. J., et al. (2012) FEBS J. 279, 1632–1639]. The possibility of discriminating the radical intermediates by their EPR spectra allowed us to identify Tyr71• as the reactive species with the guaiacol substrate. Our assignment of the surface-exposed Tyr236 as the other radical site agrees well with previous studies based on MNP labeling and protein cross-linking [Tsaprailis, G., and English, A. M. (2003) JBIC, J. Biol. Inorg. Chem. 8, 248–255] and on its covalent modification upon reaction of W191G CcP with 2-aminotriazole [Musah, R. A., and Goodin, D. B. (1997) Biochemistry 36, 11665–11674]. Accordingly, while Tyr71 acts as a true reactive intermediate for the oxidation of certain small substrates that bind at a site remote from the heme, the surface-exposed Tyr236 would be more likely related to oxidative stress

  12. The role of redox-active amino acids on compound I stability, substrate oxidation, and protein cross-linking in yeast cytochrome C peroxidase.

    PubMed

    Pfister, T D; Gengenbach, A J; Syn, S; Lu, Y

    2001-12-11

    The role of two tryptophans (Trp51 and Trp191) and six tyrosines (Tyr36, Tyr39, Tyr42, Tyr187, Tyr229, and Tyr236) in yeast cytochrome c peroxidase (CcP) has been probed by site-directed mutagenesis. A series of sequential mutations of these redox-active amino acid residues to the corresponding, less oxidizable residues in lignin peroxidase (LiP) resulted in an increasingly more stable compound I, with rate constants for compound I decay decreasing from 57 s(-1) for CcP(MI, W191F) to 7 s(-1) for CcP(MI, W191F,W51F,Y187F,Y229F,Y236F,Y36F,Y39E,Y42F). These results provide experimental support for the proposal that the stability of compound I depends on the number of endogenous oxidizable amino acids in proteins. The higher stability of compound I in the variant proteins also makes it possible to observe its visible absorption spectroscopic features more clearly. The effects of the mutations on oxidation of ferrocytochrome c and 2,6-dimethoxyphenol were also examined. Since the first mutation in the series involved the change of Trp191, a residue that plays a critical role in the electron transfer pathway between CcP and cyt c, the ability to oxidize cyt c was negligible for all mutant proteins. On the other hand, the W191F mutation had little effect on the proteins' ability to oxidize 2,6-dimethoxyphenol. Instead, the W51F mutation resulted in the largest increase in the k(cat)/K(M), from 2.1 x 10(2) to 5.0 x 10(3) M(-1) s(-1), yielding an efficiency that is comparable to that of manganese peroxidase (MnP). The effect in W51F mutation can be attributed to the residue's influence on the stability and thus reactivity of the ferryl oxygen of compound II, whose substrate oxidation is the rate-determining step in the reaction mechanism. Finally, out of all mutant proteins in this study, only the variant containing the Y36F, Y39E, and Y42F mutations was found to prevent covalent protein cross-links in the presence of excess hydrogen peroxide and in the absence of exogenous

  13. A hot-spot-active magnetic graphene oxide substrate for microRNA detection based on cascaded chemiluminescence resonance energy transfer.

    PubMed

    Bi, Sai; Chen, Min; Jia, Xiaoqiang; Dong, Ying

    2015-02-28

    Herein, a cascaded chemiluminescence resonance energy transfer (C-CRET) process was demonstrated from horseradish peroxidase (HRP)-mimicking DNAzyme-catalyzed luminol-H2O2 to fluorescein and further to graphene oxide (GO) when HRP-mimicking DNAzyme/fluorescein was in close proximity to the GO surface. The proposed C-CRET system was successfully implemented to construct three modes of C-CRET hot-spot-active substrates (modes I, II and III) by covalently immobilizing HRP-mimicking DNAzyme/fluorescein-labeled hairpin DNAs (hot-spot-generation probes) on magnetic GO (MGO), resulting in a signal "off" state due to the quenching of the luminol/H2O2/HRP-mimicking DNAzyme/fluorescein CRET system by GO. Upon the introduction of microRNA-122 (miRNA-122), the targets (mode I) or the new triggers that were generated through a strand displacement reaction (SDR) initiated by miRNA-122 (modes II and III) hybridized with the loop domains of hairpin probes on MGO to form double-stranded (modes I and II) or triplex-stem structures (mode III), causing an "open" configuration of the hairpin probe and a CRET signal "on" state, thus achieving sensitive and selective detection of miRNA-122. More importantly, the substrate exhibited excellent controllability, reversibility and reproducibility through SDR and magnetic separation (modes II and III), especially sequence-independence for hairpin probes in mode III, holding great potential for the development of a versatile platform for optical biosensing. PMID:25644330

  14. Synthesis of zinc oxide nanostructures on graphene/glass substrate by electrochemical deposition: effects of current density and temperature.

    PubMed

    Hambali, Nur Ashikyn; Yahaya, Hafizal; Mahmood, Mohamad Rusop; Terasako, Tomoaki; Hashim, Abdul Manaf

    2014-01-01

    The electrochemical growth of zinc oxide (ZnO) nanostructures on graphene on glass using zinc nitrate hexahydrate was studied. The effects of current densities and temperatures on the morphological, structural, and optical properties of the ZnO structures were studied. Vertically aligned nanorods were obtained at a low temperature of 75°C, and the diameters increased with current density. Growth temperature seems to have a strong effect in generating well-defined hexagonal-shape nanorods with a smooth top edge surface. A film-like structure was observed for high current densities above -1.0 mA/cm(2) and temperatures above 80°C due to the coalescence between the neighboring nanorods with large diameter. The nanorods grown at a temperature of 75°C with a low current density of -0.1 mA/cm(2) exhibited the highest density of 1.45 × 10(9) cm(-2). X-ray diffraction measurements revealed that the grown ZnO crystallites were highly oriented along the c-axis. The intensity ratio of the ultraviolet (UV) region emission to the visible region emission, I UV/I VIS, showed a decrement with the current densities for all grown samples. The samples grown at the current density below -0.5 mA/cm(2) showed high I UV/I VIS values closer to or higher than 1.0, suggesting their fewer structural defects. For all the ZnO/graphene structures, the high transmittance up to 65% was obtained at the light wavelength of 550 nm. Structural and optical properties of the grown ZnO structures seem to be effectively controlled by the current density rather than the growth temperature. ZnO nanorod/graphene hybrid structure on glass is expected to be a promising structure for solar cell which is a conceivable candidate to address the global need for an inexpensive alternative energy source. PMID:25411567

  15. Synthesis of zinc oxide nanostructures on graphene/glass substrate by electrochemical deposition: effects of current density and temperature

    PubMed Central

    2014-01-01

    The electrochemical growth of zinc oxide (ZnO) nanostructures on graphene on glass using zinc nitrate hexahydrate was studied. The effects of current densities and temperatures on the morphological, structural, and optical properties of the ZnO structures were studied. Vertically aligned nanorods were obtained at a low temperature of 75°C, and the diameters increased with current density. Growth temperature seems to have a strong effect in generating well-defined hexagonal-shape nanorods with a smooth top edge surface. A film-like structure was observed for high current densities above -1.0 mA/cm2 and temperatures above 80°C due to the coalescence between the neighboring nanorods with large diameter. The nanorods grown at a temperature of 75°C with a low current density of -0.1 mA/cm2 exhibited the highest density of 1.45 × 109 cm-2. X-ray diffraction measurements revealed that the grown ZnO crystallites were highly oriented along the c-axis. The intensity ratio of the ultraviolet (UV) region emission to the visible region emission, IUV/IVIS, showed a decrement with the current densities for all grown samples. The samples grown at the current density below -0.5 mA/cm2 showed high IUV/IVIS values closer to or higher than 1.0, suggesting their fewer structural defects. For all the ZnO/graphene structures, the high transmittance up to 65% was obtained at the light wavelength of 550 nm. Structural and optical properties of the grown ZnO structures seem to be effectively controlled by the current density rather than the growth temperature. ZnO nanorod/graphene hybrid structure on glass is expected to be a promising structure for solar cell which is a conceivable candidate to address the global need for an inexpensive alternative energy source. PMID:25411567

  16. Energy Expenditure and Substrate Oxidation in Response to Side-Alternating Whole Body Vibration across Three Commonly-Used Vibration Frequencies

    PubMed Central

    Fares, Elie-Jacques; Charrière, Nathalie; Montani, Jean-Pierre; Schutz, Yves; Dulloo, Abdul G.; Miles-Chan, Jennifer L.

    2016-01-01

    Background and Aim There is increasing recognition about the importance of enhancing energy expenditure (EE) for weight control through increases in low-intensity physical activities comparable with daily life (1.5–4 METS). Whole-body vibration (WBV) increases EE modestly and could present both a useful adjuvant for obesity management and tool for metabolic phenotyping. However, it is unclear whether a “dose-response” exists between commonly-used vibration frequencies (VF) and EE, nor if WBV influences respiratory quotient (RQ), and hence substrate oxidation. We aimed to investigate the EE-VF and RQ-VF relationships across three different frequencies (30, 40, and 50Hz). Methods EE and RQ were measured in 8 healthy young adults by indirect calorimetry at rest, and subsequently during side-alternating WBV at one of 3 VFs (30, 40, and 50 Hz). Each frequency was assessed over 5 cycles of intermittent WBV (30s vibration/30s rest), separated by 5 min seated rest. During the WBV participants stood on the platform with knees flexed sufficiently to maintain comfort, prevent transmission of vibration to the upper body, and minimise voluntary physical exertion. Repeatability was assessed across 3 separate days in a subset of 4 individuals. In order to assess any sequence/habituation effect, an additional group of 6 men underwent 5 cycles of intermittent WBV (30s vibration/30s rest) at 40 Hz, separated by 5 min seated rest. Results Side-alternating WBV increased EE relative to standing, non-vibration levels (+36%, p<0.001). However, no differences in EE were observed across VFs. Similarly, no effect of VF on RQ was found, nor did WBV alter RQ relative to standing without vibration. Conclusion No relationship could be demonstrated between EE and VF in the range of 30-50Hz, and substrate oxidation did not change in response to WBV. Furthermore, the thermogenic effect of intermittent WBV, whilst robust, was quantitatively small (<2 METS). PMID:26974147

  17. Methods of repairing a substrate

    NASA Technical Reports Server (NTRS)

    Riedell, James A. (Inventor); Easler, Timothy E. (Inventor)

    2011-01-01

    A precursor of a ceramic adhesive suitable for use in a vacuum, thermal, and microgravity environment. The precursor of the ceramic adhesive includes a silicon-based, preceramic polymer and at least one ceramic powder selected from the group consisting of aluminum oxide, aluminum nitride, boron carbide, boron oxide, boron nitride, hafnium boride, hafnium carbide, hafnium oxide, lithium aluminate, molybdenum silicide, niobium carbide, niobium nitride, silicon boride, silicon carbide, silicon oxide, silicon nitride, tin oxide, tantalum boride, tantalum carbide, tantalum oxide, tantalum nitride, titanium boride, titanium carbide, titanium oxide, titanium nitride, yttrium oxide, zirconium boride, zirconium carbide, zirconium oxide, and zirconium silicate. Methods of forming the ceramic adhesive and of repairing a substrate in a vacuum and microgravity environment are also disclosed, as is a substrate repaired with the ceramic adhesive.

  18. Metal-oxide buffer layer for maintaining topological bumpy surface underlayer of columnar CoPt-SiO2 granular media deposited at high substrate temperature

    NASA Astrophysics Data System (ADS)

    Tham, Kim Kong; Hinata, Shintaro; Saito, Shin; Takahashi, Migaku

    2015-05-01

    Investigation of surface topography for underlayer with various metal-oxide buffer layer (BL) materials for magnetic recording media is reported. In the previous study, it was found out that the application of a high substrate temperature deposition process to a granular layer with a magnetic alloy and a non-magnetic oxide material, such as CoPtCr-SiO2, will induce lamellar and spherical grains due to the flattening of the underlayer bumpy surface by recrystallization. By depositing a CoCr-SiO2 BL onto the Ru underlayer at room temperature, CoCr grains grow epitaxially onto Ru grains and SiO2 segregates to Ru boundaries. Consequently, bumpy surface morphology of the underlayer is maintained even though heated to around 400 °C before depositing the granular layer. Therefore, CoPt magnetic grains of a Co82.4Pt17.6- 27.7 vol. % SiO2 granular film deposited on the underlayer grow epitaxially on CoCr grains with columnar structure. As a result, high average Ku⊥ of around 6.7 × 106 erg/cm3 can be obtained. Among the studied BL materials, CoCr-SiO2 shows the highest thermal resistance with root mean square surface roughness (Rq) of around 1.7 nm after heating at around 400 °C. To obtain columnar magnetic grains with critical thickness more than 13 nm, underlayer with Rq more than 1.6 nm is needed.

  19. Characteristics of low-resistivity aluminum-doped zinc oxide films deposited at room temperature by off-axis radio-frequency sputtering on flexible plastic substrates

    NASA Astrophysics Data System (ADS)

    Wang, Li-Min; Wang, Chih-Yi; Jheng, Ciao-Ren; Wu, Syu-Jhan; Sai, Chen-Kai; Lee, Ya-Ju; Chiang, Ching-Yu; Shew, Bor-Yuan

    2016-08-01

    The crystalline structure, morphology, composition, electrical transport, and optical properties of aluminum-doped zinc oxide (AZO) films are studied for applications in transparent electronics and optoelectronic devices. AZO thin films of c-axis-oriented growth and with different thickness were deposited on PET flexible plastic substrates at room temperature by rf magnetron sputtering. A larger grain size with a decreased strain ɛ value is observed in a thicker film, while changes in composition for films with different thicknesses are insignificant. Moreover, the resistivity of film decreases with increasing thickness, and the low-temperature electrical transport properties can be described by the scenario of quantum corrections to conductivity. With the room-temperature growth conditions, the resistivity of 4.5 × 10-4 Ω cm, carrier concentration of 6.4 × 1020 cm-3, and transmittance of 80 % for the 1100-nm-thick film are obtained. In addition, the optical bandgap energy decreases with increasing film thickness, which can be attributed to the bandgap renormalization and crystallite size effects.

  20. Demethylmenaquinol is a substrate of Escherichia coli nitrate reductase A (NarGHI) and forms a stable semiquinone intermediate at the NarGHI quinol oxidation site.

    PubMed

    Rendon, Julia; Pilet, Eric; Fahs, Zeinab; Seduk, Farida; Sylvi, Léa; Hajj Chehade, Mahmoud; Pierrel, Fabien; Guigliarelli, Bruno; Magalon, Axel; Grimaldi, Stephane

    2015-08-01

    Quinones are essential building blocks of respiration, a universal process dedicated to efficient harvesting of environmental energy and its conversion into a transmembrane chemiosmotic potential. Quinones differentiate mostly by their midpoint redox potential. As such, γ-proteobacteria such as Escherichia coli are characterized by the presence of demethylmenaquinone (DMK) with an intermediate redox potential between low-potential (menaquinone) and high-potential (ubiquinone) quinones. In this study, we show that demethylmenaquinol (DMKH2) is a good substrate for nitrate reductase A (NarGHI) in nitrate respiration in E. coli. Kinetic studies performed with quinol analogs on NarGHI show that removal of the methyl group on the naphthoquinol ring impacts modestly the catalytic constant but not the KM. EPR-monitored redox titrations of NarGHI-enriched membrane vesicles reveal that endogeneous demethylmenasemiquinone (DMSK) intermediates are stabilized in the enzyme. The measured midpoint potential of the DMK/DMKH2 redox couple in NarGHI (E'm,7.5 (DMK/DMKH2) ~-70mV) is significantly lower than that previously measured for unbound species. High resolution pulsed EPR experiments demonstrate that DMSK are formed within the NarGHI quinol oxidation site. Overall, our results provide the first characterization of a protein-bound DMSK and allows for comparison for distinct use of three quinones at a single Q-site in NarGHI. PMID:25976528