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Sample records for growth substrate depending

  1. Effect of Trichoderma on horticultural seedlings' growth promotion depending on inoculum and substrate type.

    Science.gov (United States)

    Marín-Guirao, J I; Rodríguez-Romera, P; Lupión-Rodríguez, B; Camacho-Ferre, F; Tello-Marquina, J C

    2016-10-01

    The biostimulant effect of Trichoderma spp. on horticultural crops are highly variable. Thus, practical use of Trichoderma sp. requires feasible formulated products and suitable substrates. This study evaluates the survival and the growth-promotion effect of a Trichoderma saturnisporum rice formulation compared with a nonformulated conidia suspension (seven treatments in total), on tomato, pepper and cucumber seedlings grown in two substrates: (i) rich in organic matter (OM) and (ii) mineral substrate without OM. The results showed beneficial effects on seedling growth in the OM-rich substrate when T. saturnisporum rice formulation (mainly at maximum concentration) was applied, but the effects were opposite when the mineral substrate without OM was used. The effects were closely linked to the level of inoculum in the substrate, which was greater upon application of the formulated inoculum as opposed to the nonformulated one. The use of rice to prepare the inoculum of T. saturnisporum seems to be promising for seedling growth in the nursery when it is applied in a substrate that is rich in organic matter, but it must be considered that under certain conditions of food shortage, Trichoderma sp. could show pathogenicity to seedlings. This study provides evidence of the complexity inherent in the use of micro-organisms in agriculture, while also confirming that the activity of the biofertilizers based on Trichoderma depends on the type of inoculum and its concentration, as well as the properties of the medium in which the fungi develop. Further studies assessing the effectiveness or possible pathogenicity of Trichoderma in different soils under greenhouse conditions must be addressed. © 2016 The Society for Applied Microbiology.

  2. Temperature dependence of ordered GeSi island growth on patterned Si (001) substrates

    International Nuclear Information System (INIS)

    ZhongZhenyang; Chen Peixuan; Jiang Zuimin; Bauer, Guenther

    2008-01-01

    Statistical information on GeSi islands grown on two-dimensionally pit-patterned Si substrates at different temperatures is presented. Three growth regimes on patterned substrates are identified: (i) kinetically limited growth at low growth temperatures, (ii) ordered island growth in an intermediate temperature range, and (iii) stochastic island growth within pits at high temperatures. A qualitative model based on growth kinetics is proposed to explain these phenomena. It can serve as a guidance to realize optimum growth conditions for ordered islands on patterned substrates

  3. Substrate structure dependence of the growth modes of p-quaterphenyl thin films on gold

    International Nuclear Information System (INIS)

    Muellegger, S.; Mitsche, S.; Poelt, P.; Haenel, K.; Birkner, A.; Woell, C.; Winkler, A.

    2005-01-01

    The variably oriented crystallite surfaces of a recrystallized polycrystalline gold sample served as substrates for the investigation of the structure dependence of p-quaterphenyl (4P) thin film growth. The films were prepared in ultrahigh vacuum by organic molecular beam evaporation. Optical microscopy, scanning electron microscopy, combined with laterally resolved electron backscatter diffraction and scanning tunnelling microscopy have been applied to determine the correlation between the substrate surface structure and 4P film morphology. Crystallite surfaces consisting of (110) terraces favour highly anisotropic needle-like 4P growth with the needle orientation normal to the Au directions. Atomic steps on vicinal planes with narrow terraces (< 2 nm) can also induce anisotropy in the 4P thin film growth, in particular elongated 4P islands normal to the step direction. In contrast to that, a nearly isotropic distribution of the needle orientations is observed on Au grains terminated by highly symmetric (111) or (100) crystal planes. Additionally, patches of continuous 4P layers can be found on these surfaces. There is strong evidence that the 4P molecules within the needle-like crystallites are oriented parallel to the Au surface, whereas for the continuous layers the 4P molecules are oriented nearly upright on the surface

  4. Growth and flowering of Helleborus argutifolius (Viviani grown in pots depending on substrate type

    Directory of Open Access Journals (Sweden)

    Monika Henschke

    2014-09-01

    Full Text Available An experiment was conducted on the effect of substrate type on growth of Corsican hellebore (Helleborus argutifolius Viviani. Plants were grown for two years in pots with substrates whose components included Klasmann highmoor peat and Hartmann highmoor peat, mineral soil, expanded clay and perlite at various volumetric ratios. Vegetative growth and flowering were observed in hellebores. It was shown that substrates exhibited a varied effect on plant growth. Corsican hellebore in a substrate with a considerable addition of mineral soil was lower, but more branched, and it did not form inflorescences. An optimal medium for growing H. argutifolius in pots was Hartmann’s de-acidified peat + mineral soil (1:1 v:v. In this medium vegetative growth of plants was extensive, flowering was early and abundant, and long peduncles were produced.

  5. Temperature dependence of InN growth on (0001) sapphire substrates by atmospheric pressure hydride vapor phase epitaxy

    International Nuclear Information System (INIS)

    Kumagai, Yoshinao; Adachi, Hirokazu; Otake, Aya; Higashikawa, Yoshihiro; Togashi, Rie; Murakami, Hisashi; Koukitu, Akinori

    2010-01-01

    The temperature dependence of InN growth on (0001) sapphire substrates by atmospheric pressure hydride vapor phase epitaxy (HVPE) was investigated. N-polarity single-crystal InN layers were successfully grown at temperatures ranging from 400 to 500 C. The a and c lattice constants of InN layers grown at 450 C or below were slightly larger than those of InN layers grown above 450 C due to oxygen incorporation that also increased the carrier concentration. The optical absorption edge of the InN layer decreased from above 2.0 to 0.76 eV when the growth temperature was increased from 450 to 500 C. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Maintenance-energy-dependent dynamics of growth and poly(3-hydroxybutyrate [P(3HB] production by Azohydromonas lata MTCC 2311 using simple and renewable carbon substrates

    Directory of Open Access Journals (Sweden)

    M. Zafar

    2014-06-01

    Full Text Available The dynamics of microbial growth and poly(3-hydroxybutyrate [P(3HB] production in growth/ non-growth phases of Azhohydromonas lata MTCC 2311 were studied using a maintenance-energy-dependent mathematical model. The values of calculated model kinetic parameters were: m s1 = 0.0005 h-1, k = 0.0965, µmax = 0.25 h-1 for glucose; m s1 = 0.003 h-1, k = 0.1229, µmax = 0.27 h-1 for fructose; and m s1 = 0.0076 h-1, k = 0.0694, µmax = 0.25 h-1 for sucrose. The experimental data of biomass growth, substrate consumption, and P(3HB production on different carbon substrates were mathematically fitted using non-linear least square optimization technique and similar trends, but different levels were observed at varying initial carbon substrate concentration. Further, on the basis of substrate assimilation potential, cane molasses was used as an inexpensive and renewable carbon source for P(3HB production. Besides, the physico-chemical, thermal, and material properties of synthesized P(3HB were determined which reveal its suitability in various applications.

  7. Distinction of [220] and [204] textures of Cu(In,Ga)Se{sub 2} film and their growth behaviors depending on substrate nature and Na incorporation

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Dae-Hyung, E-mail: dhcho@etri.re.kr [IT Components and Materials Industry Technology Research Department, Electronics and Telecommunications Research Institute (ETRI), 218 Gajeongno, Yuseong-gu, Daejeon 305-700 (Korea, Republic of); Kim, Jeha [Department of Solar & Energy Engineering, Cheongju University, 298 Daeseongro, Sangdang-gu, Cheongju, Chungbuk 360-764 (Korea, Republic of); Chung, Yong-Duck [IT Components and Materials Industry Technology Research Department, Electronics and Telecommunications Research Institute (ETRI), 218 Gajeongno, Yuseong-gu, Daejeon 305-700 (Korea, Republic of); Korea University of Science and Technology (UST), 217 Gajeongno, Yuseong-gu, Daejeon 305-350 (Korea, Republic of)

    2015-08-31

    For better understanding of the structural property of polycrystalline tetragonal Cu(In,Ga)Se{sub 2} (CIGS) thin films grown on soda-lime glass, it is necessary to characterize the [220]- and [204]-oriented textures clearly that are related to the different physical properties. However, the distinction between the [220]- and [204]-oriented textures is very difficult because of their nearly identical plane spacings and atomic arrangements. Using X-ray diffraction techniques of high resolution θ–2θ scanning and reciprocal space mapping, we distinguished the [220]- and [204]-oriented textures of CIGS films and observed that the behaviors of [220] and [204] textures independently depended on both substrate nature and Na presence. We report the Na- and substrate-related dependence of the physical properties of the CIGS film was attributed to the independent growth behaviors of the [220] and [204] textures in the CIGS. - Highlights: • We investigated [220]- and [204]-oriented textures of Cu(In,Ga)Se{sub 2} (CIGS) films. • X-ray diffraction methods distinguished two textures. • The growth behaviors were influenced by underlying substrate and Na. • The [220] and [204] textures in CIGS should be differentially observed.

  8. Olive mill wastewater triggered changes in physiology and nutritional quality of tomato (Lycopersicon esculentum mill) depending on growth substrate.

    Science.gov (United States)

    Ouzounidou, G; Asfi, M; Sotirakis, N; Papadopoulou, P; Gaitis, F

    2008-10-30

    We have studied the changes in the physiology and nutritional quality of Lycopersicon esculentum exposed to olive mill wastewater (OMW) with regard to cultivation in sand and soil. Tomato plant performance decreased with increasing concentration of OMW to both substrates. Root was more sensitive to OMW than the upper parts of the plants, grown either in sand or in soil for 10 days and 3 months, respectively, probably due to the direct OMW toxicity on roots as compared to other parts. Significant restriction on uptake and translocation of nutrients (K, Na, Fe, Ca and Mg) under OMW application was found. The decrease in the photochemical efficiency of PSII photochemistry in the light adapted state and the big decrease in photochemical quenching, indicate that OMW resulted in diminished reoxidation of Q(A)(-) and started to inactivate the reaction centers of PSII. The OMW supply on soil and sand, resulted in leaf water stress and lesser water use efficiency. Plants treated with high OMW concentration, produced fewer but bigger tomatoes as compared to plants treated with lower OMW concentration. Generally, fruit yield and nutritional value was inhibited under OMW application.

  9. Biomimetic growth and substrate dependent mechanical properties of bone like apatite nucleated on Ti and magnetron sputtered TiO2 nanostructure

    Science.gov (United States)

    Sarma, Bimal K.; Das, Apurba; Barman, Pintu; Pal, Arup R.

    2016-04-01

    This report presents findings on biomimetic growth of hydroxyapatite (HAp) nanocrystals on Ti and sputtered TiO2 substrates. The possibility of TiO2 nanostructure as candidate materials for future biomedical applications has been explored through the comparison of microstructural and mechanical properties of bone like apatite grown on Ti and nano-TiO2 surfaces. Raman spectroscopy and x-ray diffraction studies reveal formation of carbonate apatite with apparent domain size in the nanoscale range. A better interaction at the nano-TiO2/nano-HAp interface due to higher interfacial area could promote the growth of bone like apatite. The crystal phases, crystallinity, and surface morphology of nano-TiO2 are considered as parameters to understand the nucleation and growth of apatite with different mechanical properties at the nanoscale. The methodology of x-ray line profile analysis encompasses deconvolution of merged peaks by preserving broadening due to nanosized HAp aggregates. The Young’s modulus of bone like apatite exhibits crystallographic directional dependence which suggests the presence of elastic anisotropy in bone like apatite. The lattice contraction in the c-direction is associated with the degree of carbonate substitution in the apatite lattice. The role of residual stress is critical for the lattice distortion of HAp deposited at physiological conditions of temperature and pH of human blood plasma. The ion concentration is crucial for the uniformity, crystallinity, and mechanical behaviour of the apatite.

  10. Biomimetic growth and substrate dependent mechanical properties of bone like apatite nucleated on Ti and magnetron sputtered TiO2 nanostructure

    International Nuclear Information System (INIS)

    Sarma, Bimal K; Das, Apurba; Barman, Pintu; Pal, Arup R

    2016-01-01

    This report presents findings on biomimetic growth of hydroxyapatite (HAp) nanocrystals on Ti and sputtered TiO 2 substrates. The possibility of TiO 2 nanostructure as candidate materials for future biomedical applications has been explored through the comparison of microstructural and mechanical properties of bone like apatite grown on Ti and nano-TiO 2 surfaces. Raman spectroscopy and x-ray diffraction studies reveal formation of carbonate apatite with apparent domain size in the nanoscale range. A better interaction at the nano-TiO 2 /nano-HAp interface due to higher interfacial area could promote the growth of bone like apatite. The crystal phases, crystallinity, and surface morphology of nano-TiO 2 are considered as parameters to understand the nucleation and growth of apatite with different mechanical properties at the nanoscale. The methodology of x-ray line profile analysis encompasses deconvolution of merged peaks by preserving broadening due to nanosized HAp aggregates. The Young’s modulus of bone like apatite exhibits crystallographic directional dependence which suggests the presence of elastic anisotropy in bone like apatite. The lattice contraction in the c-direction is associated with the degree of carbonate substitution in the apatite lattice. The role of residual stress is critical for the lattice distortion of HAp deposited at physiological conditions of temperature and pH of human blood plasma. The ion concentration is crucial for the uniformity, crystallinity, and mechanical behaviour of the apatite. (paper)

  11. Growth-dependent modulation of casein kinase II and its substrate nucleolin in primary human cell cultures and HeLa cells

    DEFF Research Database (Denmark)

    Schneider, H R; Issinger, O G

    1989-01-01

    We have previously provided evidence that casein kinase II (CKII) and its substrate nucleolin increase concomitantly during certain development stages during embryogenesis (Schneider et al., Eur. J. Biochem. 161, 733-738). We now show that during normal growth of primary cell cultures and He...

  12. The dependence of the wavelength on MBE growth parameters of GaAs quantum dot in AlGaAs NWs on Si (111) substrate

    Science.gov (United States)

    Reznik, R. R.; Shtrom, I. V.; Samsonenko, Yu B.; Khrebtov, A. I.; Soshnikov, I. P.; Cirlin, G. E.

    2017-11-01

    The data on the growth peculiarities and physical properties of GaAs insertions embedded in AlGaAs nanowires grown on Si (111) substrates by Au-assisted molecular beam epitaxy are presented. It is shown that by varying of the growth parameters it is possible to form structures like quantum dots emitting in a wide wavelengths range for both active and barrier parts. The technology proposed opens new possibilities for the integration of direct-band AIIIBV materials on silicon platform.

  13. Microbial growth and substrate utilization kinetics | Okpokwasili ...

    African Journals Online (AJOL)

    Microbial growth on and utilization of environmental contaminants as substrates have been studied by many researchers. Most times, substrate utilization results in removal of chemical contaminant, increase in microbial biomass and subsequent biodegradation of the contaminant. These are all aimed at detoxification of the ...

  14. Maintenance-energy-dependent dynamics of growth and poly(3-hydroxybutyrate) [P(3HB)] production by Azohydromonas lata MTCC 2311 using simple and renewable carbon substrates

    OpenAIRE

    Zafar,M.; Kumar,S.; Kumar,S.; Dhiman,A. K.; Park,H.-S.

    2014-01-01

    The dynamics of microbial growth and poly(3-hydroxybutyrate) [P(3HB)] production in growth/ non-growth phases of Azhohydromonas lata MTCC 2311 were studied using a maintenance-energy-dependent mathematical model. The values of calculated model kinetic parameters were: m s1 = 0.0005 h-1, k = 0.0965, µmax = 0.25 h-1 for glucose; m s1 = 0.003 h-1, k = 0.1229, µmax = 0.27 h-1 for fructose; and m s1 = 0.0076 h-1, k = 0.0694, µmax = 0.25 h-1 for sucrose. The experimental data of biomass growth, sub...

  15. Anaerobic digestion characteristics of pig manures depending on various growth stages and initial substrate concentrations in a scaled pig farm in Southern China.

    Science.gov (United States)

    Zhang, Wanqin; Lang, Qianqian; Wu, Shubiao; Li, Wei; Bah, Hamidou; Dong, Renjie

    2014-03-01

    The characteristics of anaerobic digestion of pig manure from different growth stages were investigated. According to growth stage, batch experiments were performed using gestating sow manure (GSM), swine nursery with post-weaned piglet manure (SNM), growing fattening manure (GFM) and mixed manure (MM) as substrates at four substrate concentrations (40, 50, 65 and 80gVS/L) under mesophilic conditions. The maximum methane yields of MM, SNM, GSM and GFM were 354.7, 328.7, 282.4 and 263.5mLCH4/gVSadded, respectively. Volatile fatty acids/total inorganic carbon (VFA/TIC) ratio increased from 0.10 to 0.89 when loading increased from 40 to 80gVS/L for GFM. The modified Gompertz model shows a better fit to the experimental results than the first order model with a lower difference between measured and predicted methane yields. The kinetic parameters indicated that the methane production curve on the basis of differences in biodegradability of the pig manure at different growth stages. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Influence of nutrition and various substrates on spruce seedling growth

    Directory of Open Access Journals (Sweden)

    Đukić Matilda

    2004-01-01

    Full Text Available The results of the influence of main macronutrients (N, P, and K on growth and development of spruce (Picea abies L. Karst one-year old seedlings are presented. They were grown in containers, in nursery conditions, on four different substrates. There is a good influence on biogenous element contents, height, root collar diameter, needle length and mass, root mass as well as physiological vitality of spruce seedlings. It was observed that the effect of nutrition depends also on the type of substrate.

  17. Alloyed surfaces: New substrates for graphene growth

    Science.gov (United States)

    Tresca, C.; Verbitskiy, N. I.; Fedorov, A.; Grüneis, A.; Profeta, G.

    2017-11-01

    We report a systematic ab-initio density functional theory investigation of Ni(111) surface alloyed with elements of group IV (Si, Ge and Sn), demonstrating the possibility to use it to grow high quality graphene. Ni(111) surface represents an ideal substrate for graphene, due to its catalytic properties and perfect matching with the graphene lattice constant. However, Dirac bands of graphene growth on Ni(111) are completely destroyed due to the strong hybridization between carbon pz and Ni d orbitals. Group IV atoms, namely Si, Ge and Sn, once deposited on Ni(111) surface, form an ordered alloyed surface with √{ 3} ×√{ 3} -R30° reconstruction. We demonstrate that, at variance with the pure Ni(111) surface, alloyed surfaces effectively decouple graphene from the substrate, resulting unstrained due to the nearly perfect lattice matching and preserves linear Dirac bands without the strong hybridization with Ni d states. The proposed surfaces can be prepared before graphene growth without resorting on post-growth processes which necessarily alter the electronic and structural properties of graphene.

  18. Directional growth of Ag nanorod from polymeric silver cyanide: A potential substrate for concentration dependent SERS signal enhancement leading to melamine detection

    Science.gov (United States)

    Roy, Anindita; Sahoo, Ramkrishna; Chowdhury, Joydeep; Bhattacharya, Tara Shankar; Agarwal, Ratnesh; Pal, Tarasankar

    2017-08-01

    Attention has been directed to prepare exclusive one-dimensional silver nanostructure from the linear inorganic polymer AgCN. Successive color change from yellow to orange, to red and finally to green reflects the evolution of high yielding Ag nanorods (NRs) from well-known -[Ag-CN]- chains of polymeric AgCN at room temperature. The parental 1D morphology of AgCN is retained within the as-synthesized Ag NRs. So we could successfully exploit the Ag NR for surface-enhanced Raman scattering (SERS) studies for sensing a popular milk adulterant melamine down to picomolar level. We observed interesting concentration dependent selective SERS band enhancement of melamine. The enhanced 1327 cm- 1 SERS signal intensity at lower concentration (10- 9 and 10- 12 M) of melamine speaks for the preferential participation of -C-N of melamine molecule with Ag surface. On the other hand, '-NH2' group together with ring 'N' participation of melamine molecule onto Ag surface suggested an adsorptive stance at higher (10- 3-10- 7 M) concentration range. Thus the binding modes of the molecule at the Ag surface justify its fluxional behavior.

  19. Effects of mixed substrates on growth and vitamin production by ...

    African Journals Online (AJOL)

    SERVER

    2007-10-16

    Oct 16, 2007 ... The cells were grown mixotrophically in glucose (G), ethanol ... Key words: mixed substrate culture, Euglena gracilis, cell growth, vitamin production. ..... Biological elimination of nitric oxide from fuel gas by marine micro-.

  20. Connective tissue growth factor is a substrate of ADAM28

    International Nuclear Information System (INIS)

    Mochizuki, Satsuki; Tanaka, Rena; Shimoda, Masayuki; Onuma, Junko; Fujii, Yutaka; Jinno, Hiromitsu; Okada, Yasunori

    2010-01-01

    Research highlights: → The hyper-variable region in the cysteine-rich domain of ADAM28 binds to C-terminal domain of CTGF. → ADAM28 cleaves CTGF alone and CTGF in the CTGF/VEGF 165 complex. → CTGF digestion by ADAM28 releases biologically active VEGF 165 from the complex. → ADAM28, CTGF and VEGF 165 are commonly co-expressed by carcinoma cells in human breast carcinoma tissues. → These suggest that ADAM28 promotes VEGF 165 -induced angiogenesis in the breast carcinomas by selective CTGF digestion in the CTGF/VEGF 165 complex. -- Abstract: ADAM28, a member of the ADAM (a disintegrin and metalloproteinase) gene family, is over-expressed by carcinoma cells and the expression correlates with carcinoma cell proliferation and progression in human lung and breast carcinomas. However, information about substrates of ADAM28 is limited. We screened interacting molecules of ADAM28 in human lung cDNA library by yeast two-hybrid system and identified connective tissue growth factor (CTGF). Binding of CTGF to proADAM28 was demonstrated by yeast two-hybrid assay and protein binding assay. ADAM28 cleaved CTGF in dose- and time-dependent manners at the Ala 181 -Tyr 182 and Asp 191 -Pro 192 bonds in the hinge region of the molecule. ADAM28 selectively digested CTGF in the complex of CTGF and vascular endothelial growth factor 165 (VEGF 165 ), releasing biologically active VEGF 165 from the complex. RT-PCR and immunohistochemical analyses demonstrated that ADAM28, CTGF and VEGF are commonly co-expressed in the breast carcinoma tissues. These data provide the first evidence that CTGF is a novel substrate of ADAM28 and suggest that ADAM28 may promote VEGF 165 -induced angiogenesis in the breast carcinomas by the CTGF digestion in the CTGF/VEGF 165 complex.

  1. Fluorination of some highly functionalized cycloalkanes: chemoselectivity and substrate dependence

    Directory of Open Access Journals (Sweden)

    Attila Márió Remete

    2017-11-01

    Full Text Available A study exploring the chemical behavior of some dihydroxylated β-amino ester stereo- and regioisomers, derived from unsaturated cyclic β-amino acids is described. The nucleophilic fluorinations involving hydroxy–fluorine exchange of some highly functionalized alicyclic diol derivatives have been carried out in view of selective fluorination, investigating substrate dependence, neighboring group assistance and chemodifferentiation.

  2. Fluorination of some highly functionalized cycloalkanes: chemoselectivity and substrate dependence.

    Science.gov (United States)

    Remete, Attila Márió; Nonn, Melinda; Fustero, Santos; Haukka, Matti; Fülöp, Ferenc; Kiss, Loránd

    2017-01-01

    A study exploring the chemical behavior of some dihydroxylated β-amino ester stereo- and regioisomers, derived from unsaturated cyclic β-amino acids is described. The nucleophilic fluorinations involving hydroxy-fluorine exchange of some highly functionalized alicyclic diol derivatives have been carried out in view of selective fluorination, investigating substrate dependence, neighboring group assistance and chemodifferentiation.

  3. Catalyst–substrate interaction and growth delay in vapor–liquid–solid nanowire growth

    Science.gov (United States)

    Kolíbal, Miroslav; Pejchal, Tomáš; Musálek, Tomáš; Šikola, Tomáš

    2018-05-01

    Understanding of the initial stage of nanowire growth on a bulk substrate is crucial for the rational design of nanowire building blocks in future electronic and optoelectronic devices. Here, we provide in situ scanning electron microscopy and Auger microscopy analysis of the initial stage of Au-catalyzed Ge nanowire growth on different substrates. Real-time microscopy imaging and elementally resolved spectroscopy clearly show that the catalyst dissolves the underlying substrate if held above a certain temperature. If the substrate dissolution is blocked (or in the case of heteroepitaxy) the catalyst needs to be filled with nanowire material from the external supply, which significantly increases the initial growth delay. The experiments presented here reveal the important role of the substrate in metal-catalyzed nanowire growth and pave the way for different growth delay mitigation strategies.

  4. Acclimatization and growth of ornamental pineapple seedlings under organic substrates

    Directory of Open Access Journals (Sweden)

    Ronan Carlos Colombo

    2017-09-01

    Full Text Available The in vitro propagation techniques are commonly used to produce ornamental pineapple seedlings in commercial scale, aiming to attend the growers with genetic and sanitary quality seedlings. However, the choice of the ideal substrate is essential for the acclimatization and growth stage of the seedlings propagated by this technique, since some substrates can increase the seedling mortality and/or limit the seedling growth due to its physical and chemical characteristics. Thus, the aim of this study was to evaluate the acclimatization of ornamental pineapple [Ananas comosus (L. Merr. var. ananassoides (Baker Coppens & Leal] on different substrates. Seedlings with approximately seven centimeters, obtained from in vitro culture, were transplanted into styrofoam trays filled with the following substrates: sphagnum; semi-composed pine bark; carbonized rice husk; sphagnum + semicomposed pine bark; sphagnum + carbonized rice husk; and semi-composed pine bark + carbonized rice husk. Each treatment was replicated five times using 10 plants. At 180 days, there were evaluated the following variables: survival percentage, plant height, number of leaves, leaf area, largest root length, and shoot and root dry matter. The substrate semi-composed pine bark + carbonized rice husk presented the lowest mean (62% for survival percentage. The semi-composed pine bark and semi-composed pine bark + carbonized rice husk treatments presented significant increments in some evaluated biometric characteristics. The semi-composed pine bark is the most favorable substrate for the A. comosus var. ananassoids acclimatization.

  5. Epitaxial growth mechanisms of graphene and effects of substrates

    OpenAIRE

    Özçelik, V. Ongun; Cahangirov, S.; Ciraci, S.

    2012-01-01

    The growth process of single layer graphene with and without substrate is investigated using ab initio, finite temperature molecular dynamic calculations within density functional theory. An understanding of the epitaxial graphene growth mechanisms in the atomic level is provided by exploring the transient stages which occur at the growing edges of graphene. These stages are formation and collapse of large carbon rings together with the formation and healing of Stone-Wales like pentagon-hepta...

  6. Epitaxial growth mechanisms of graphene and effects of substrates

    Science.gov (United States)

    Özçelik, V. Ongun; Cahangirov, S.; Ciraci, S.

    2012-06-01

    The growth process of single layer graphene with and without substrate is investigated using ab initio, finite temperature molecular dynamic calculations within density functional theory. An understanding of the epitaxial graphene growth mechanisms in the atomic level is provided by exploring the transient stages which occur at the growing edges of graphene. These stages are formation and collapse of large carbon rings together with the formation and healing of Stone-Wales like pentagon-heptagon defects. The activation barriers for the healing of these growth induced defects on various substrates are calculated using the climbing image nudge elastic band method and compared with that of the Stone-Wales defect. It is found that the healing of pentagon-heptagon defects occurring near the edge in the course of growth is much easier than that of Stone-Wales defect. The role of the substrate in the epitaxial growth and in the healing of defects are also investigated in detail, along with the effects of using carbon dimers as the building blocks of graphene growth.

  7. Kinetic models of cell growth, substrate utilization and bio ...

    African Journals Online (AJOL)

    Bio-decolorization kinetic studies of distillery effluent in a batch culture were conducted using Aspergillus fumigatus. A simple model was proposed using the Logistic Equation for the growth, Leudeking-Piret kinetics for bio-decolorization, and also for substrate utilization. The proposed models appeared to provide a suitable ...

  8. Growth, Plastochron, and the Final Number of Nodes of China Pink Seedlings Grown on Different Substrates

    Directory of Open Access Journals (Sweden)

    Marília Milani

    Full Text Available ABSTRACT The objective of this work was to plot the growth curves and determine the plastochron and the final number of nodes of China pink seedlings grown on different substrates. Thus, 392 China pink seedlings were grown on seven substrates under greenhouse conditions, in Santa Maria in the state of Rio Grande do Sul, Brazil. The growth curves were plotted using the logistic model. The plastochron was estimated by the inverse of the angular coefficient of the simple linear regression between the number of accumulated nodes and accumulated thermal sum from the subsampling of the seedlings. In all substrates, the logistic model fit better for the variable number of leaves than for the plant height. The plants in substrates with 50% of soil plus 50% of rice husk ash, and 80% of rice husk ash plus 20% earthworm humus had the longest cycles with 74 and 65 days, respectively. They completed the cycles with a thermal sum of 1317.9 ºC day for number of leaves and plant height. The growth curves that were plotted by the logistic model and the plastochron of the China pink seedlings are dependent on the type of substrate used. The commercial substrate Mecplant® had the best results. The average final number of nodes of the main stem of the plants was 14 for all substrates.

  9. Neutrophil adhesion and chemotaxis depend on substrate mechanics

    International Nuclear Information System (INIS)

    Jannat, Risat A; Hammer, Daniel A; Robbins, Gregory P; Ricart, Brendon G; Dembo, Micah

    2010-01-01

    Neutrophil adhesion to the vasculature and chemotaxis within tissues play critical roles in the inflammatory response to injury and pathogens. Unregulated neutrophil activity has been implicated in the progression of numerous chronic and acute diseases such as rheumatoid arthritis, asthma and sepsis. Cell migration of anchorage-dependent cells is known to depend on both chemical and mechanical interactions. Although neutrophil responses to chemical cues have been well characterized, little is known about the effect of underlying tissue mechanics on neutrophil adhesion and migration. To address this question, we quantified neutrophil migration and traction stresses on compliant hydrogel substrates with varying elasticity in a micromachined gradient chamber in which we could apply either a uniform concentration or a precise gradient of the bacterial chemoattractant fMLP. Neutrophils spread more extensively on substrates of greater stiffness. In addition, increasing the stiffness of the substrate leads to a significant increase in the chemotactic index for each fMLP gradient tested. As the substrate becomes stiffer, neutrophils generate higher traction forces without significant changes in cell speed. These forces are often displayed in pairs and focused in the uropod. Increases in the mean fMLP concentration beyond the K D of the receptor lead to a decrease in chemotactic index on all surfaces. Blocking with an antibody against β 2 -integrins leads to a significant reduction, but not an elimination, of directed motility on stiff materials, but no change in motility on soft materials, suggesting neutrophils can display both integrin-dependent and integrin-independent motility. These findings are critical for understanding how neutrophil migration may change in different mechanical environments in vivo and can be used to guide the design of migration inhibitors that more efficiently target inflammation.

  10. Neutrophil adhesion and chemotaxis depend on substrate mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Jannat, Risat A; Hammer, Daniel A [Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210 South 33rd Street, Philadelphia, PA 19104 (United States); Robbins, Gregory P; Ricart, Brendon G [Department of Chemical and Biomolecular Engineering, University of Pennsylvania, 311A Towne Building, 220 South 33rd Street, Philadelphia, PA 19104 (United States); Dembo, Micah, E-mail: hammer@seas.upenn.ed [Department of Biomedical Engineering, Boston University, 44 Cummington Street, Boston, MA 02215 (United States)

    2010-05-19

    Neutrophil adhesion to the vasculature and chemotaxis within tissues play critical roles in the inflammatory response to injury and pathogens. Unregulated neutrophil activity has been implicated in the progression of numerous chronic and acute diseases such as rheumatoid arthritis, asthma and sepsis. Cell migration of anchorage-dependent cells is known to depend on both chemical and mechanical interactions. Although neutrophil responses to chemical cues have been well characterized, little is known about the effect of underlying tissue mechanics on neutrophil adhesion and migration. To address this question, we quantified neutrophil migration and traction stresses on compliant hydrogel substrates with varying elasticity in a micromachined gradient chamber in which we could apply either a uniform concentration or a precise gradient of the bacterial chemoattractant fMLP. Neutrophils spread more extensively on substrates of greater stiffness. In addition, increasing the stiffness of the substrate leads to a significant increase in the chemotactic index for each fMLP gradient tested. As the substrate becomes stiffer, neutrophils generate higher traction forces without significant changes in cell speed. These forces are often displayed in pairs and focused in the uropod. Increases in the mean fMLP concentration beyond the K{sub D} of the receptor lead to a decrease in chemotactic index on all surfaces. Blocking with an antibody against {beta}{sub 2}-integrins leads to a significant reduction, but not an elimination, of directed motility on stiff materials, but no change in motility on soft materials, suggesting neutrophils can display both integrin-dependent and integrin-independent motility. These findings are critical for understanding how neutrophil migration may change in different mechanical environments in vivo and can be used to guide the design of migration inhibitors that more efficiently target inflammation.

  11. Molecular Beam Epitaxial Growth of GaAs on (631) Oriented Substrates

    International Nuclear Information System (INIS)

    Cruz Hernandez, Esteban; Rojas Ramirez, Juan-Salvador; Contreras Hernandez, Rocio; Lopez Lopez, Maximo; Pulzara Mora, Alvaro; Mendez Garcia, Victor H.

    2007-01-01

    In this work, we report the study of the homoepitaxial growth of GaAs on (631) oriented substrates by molecular beam epitaxy (MBE). We observed the spontaneous formation of a high density of large scale features on the surface. The hilly like features are elongated towards the [-5, 9, 3] direction. We show the dependence of these structures with the growth conditions and we present the possibility of to create quantum wires structures on this surface

  12. The role of the substrate surface morphology and water in growth of vertically aligned single-walled carbon nanotubes.

    Science.gov (United States)

    Pint, Cary; Pheasant, Sean; Nicholas, Nolan; Horton, Charles; Hauge, Robert

    2008-11-01

    Growth of high quality, vertically aligned single-walled carbon nanotubes (carpets) is achieved using a rapid insertion hot filament chemical vapor deposition (HF-CVD) technique. The effect of the substrate morphology on growth is explored by comparing carpets grown on epitaxially polished MgO substrates to those grown on "as-cut", macroscopically rough MgO substrates. Depending on the substrate morphology, we observe differences in both the overall carpet morphology as well as the diameter distribution of nanotubes grown in the carpet based on optical measurements. In addition, we explore the role of water in the growth of carpets on MgO and the conventional Al2O3 coated Si substrates. We find that the addition of a small amount of water is beneficial to the growth rates of the SWNT carpets, enhancing the growth rates by up to eight times.

  13. Solution growth of microcrystalline silicon on amorphous substrates

    Energy Technology Data Exchange (ETDEWEB)

    Heimburger, Robert

    2010-07-05

    This work deals with low-temperature solution growth of micro-crystalline silicon on glass. The task is motivated by the application in low-cost solar cells. As glass is an amorphous material, conventional epitaxy is not applicable. Therefore, growth is conducted in a two-step process. The first step aims at the spatial arrangement of silicon seed crystals on conductive coated glass substrates, which is realized by means of vapor-liquid-solid processing using indium as the solvent. Seed crystals are afterwards enlarged by applying a specially developed steady-state solution growth apparatus. This laboratory prototype mainly consists of a vertical stack of a silicon feeding source and the solvent (indium). The growth substrate can be dipped into the solution from the top. The system can be heated to a temperature below the softening point of the utilized glass substrate. A temperature gradient between feeding source and growth substrate promotes both, supersaturation and material transport by solvent convection. This setup offers advantages over conventional liquid phase epitaxy at low temperatures in terms of achievable layer thickness and required growth times. The need for convective solute transport to gain the desired thickness of at least 50 {mu}m is emphasized by equilibrium calculations in the binary system indium-silicon. Material transport and supersaturation conditions inside the utilized solution growth crucible are analyzed. It results that the solute can be transported from the lower feeding source to the growth substrate by applying an appropriate heating regime. These findings are interpreted by means of a hydrodynamic analysis of fluid flow and supporting FEM simulation. To ensure thermodynamic stability of all materials involved during steady-state solution growth, the ternary phase equilibrium between molybdenum, indium and silicon at 600 C was considered. Based on the obtained results, the use of molybdenum disilicide as conductive coating

  14. Growth regulators and substrates for Oncidium baueri Lindl. micropropagation

    Directory of Open Access Journals (Sweden)

    Daniele Brandstetter Rodrigues

    2016-10-01

    Full Text Available An adequate concentration of growth regulators as well as the replacement of agar by an alternative medium may be promising from practical and financial points of view to produce orchid plants by micropropagation. The objective of this work was to evaluate different concentrations of growth regulator and alternative substrates for agar replacement in culture medium for in vitro multiplication and rooting of Oncidium baueri. In the explant multiplication phase, two experimental factors were evaluated- various concentrations of 6-benzylaminopurine (BAP (0.0, 1.0, 2.0, and 3.0 mg L-1 and substrates (agar, vermiculite, and coconut fiber added to MS medium. In the rooting phase, different concentrations of indole butyric acid (IBA (0.0, 0.5, 1.0, and 1.5 mg L-1 were added to culture medium containing the same substrate. Six months after the experiments were initiated, the survival percentage, number of leaves, shoots, and roots and length of the aerial part and the major root were evaluated. The results suggested that addition of 1.0 mg L-1 BAP is necessary for the O. baueri in vitro multiplication phase, but IBA is not necessary in the rooting phase. For the substrate, vermiculite is not indicated as an agar replacement. In contrast, coconut fiber can be used in both multiplication and rooting phases of Oncidium baueri in vitro culture.

  15. Selective growth of carbon nanotube on silicon substrates

    Institute of Scientific and Technical Information of China (English)

    ZOU Xiao-ping; H. ABE; T. SHIMIZU; A. ANDO; H. TOKUMOT; ZHU Shen-ming; ZHOU Hao-shen

    2006-01-01

    The carbon nanotube (CNT) growth of iron oxide-deposited trench-patterns and the locally-ordered CNT arrays on silicon substrate were achieved by simple thermal chemical vapor deposition(STCVD) of ethanol vapor. The CNTs were uniformly synthesized with good selectivity on trench-patterned silicon substrates. This fabrication process is compatible with currently used semiconductor-processing technologies,and the carbon-nanotube fabrication process can be widely applied for the development of electronic devices using carbon-nanotube field emitters as cold cathodes and can revolutionize the area of field-emitting electronic devices. The site-selective growth of CNT from an iron oxide nanoparticle catalyst patterned were also achieved by drying-mediated self-assembly technique. The present method offers a simple and cost-effective method to grow carbon nanotubes with self-assembled patterns.

  16. Epitaxial growth of nobel metals on alumina substrates

    International Nuclear Information System (INIS)

    Al-Mohammad, A.

    2007-06-01

    The influence of the reconstructed (0001) α-Al 2 O 3 surface on the heteroepitaxial growth and adhesion properties of small metal particles (gold, silver and copper) of noncontinuous thin films has been investigated. The crystallographic structure and morphology of substrate surfaces were examined by Reflection High Energy Electron Diffraction and Atomic Force Microscopy techniques. The reconstructed surfaces are terminated by one or more Aluminum atomic layers. By means of the Transmission Electronic Microscopy, the various granulometric and lattice parameters variations are investigated during different stages of the heteroepitaxial growth of metallic thin films. We estimated the adhesion energy values for each case of metal//(0001)α-Al 2 O 3 interfaces by two methods: the maximum cluster density and the Lifshits theory of Van der Waals energy of interfaces. The results of both methods are in good agreement. Using these methods, we found interfaces Hamaker's constants values and we investigated all the heteroepitaxial growth steps.(author)

  17. Temperature and angular dependence of substrate response in SEGR

    International Nuclear Information System (INIS)

    Mouret, I.; Allenspach, M.; Schrimpf, R.D.; Brews, J.R.; Galloway, K.F.

    1994-01-01

    This work examines the role of the substrate response in determining the temperature and angular dependence of Single-Event Gate Rupture (SEGR). Experimental data indicate that the likelihood of SEGR increases when the temperature of the device is increased or when the incident angle is made closer to normal. In this work, simulations are used to explore this influence of high temperature on SEGR and to support physical explanations for this effect. The reduced hole mobility at high temperature causes the hole concentration at the oxide-silicon interface to be greater, increasing the transient oxide field near the strike position. In addition, numerical calculations show that the transient oxide field decreases as the ion's angle of incidence is changed from normal. This decreased field suggests a lowered likelihood for SEGR, in agreement with the experimental trend

  18. EVALUATION OF THE GROWTH OF SELECTED LACTOBACILLI IN PSEUDOCEREAL SUBSTRATE

    Directory of Open Access Journals (Sweden)

    Denisa Liptáková

    2011-12-01

    Full Text Available The growth dynamics of Lactobacillus spp. in sweet water- and milk-based substrates from cooked buckwheat and amaranth flour were studied in this work. The numbers of lactobacilli were observed during fermentation in 5% CO2 atmosphere at 37 °C and storage (3 weeks at 6 °C. The earned data and estimated growth parameters showed that certain strains grew well in the milk-based gruels, even water-based amaranth gruel. This was also the case of the species under study characterized with the fastest growth. Based on the rates, only the strains of Lactobacillus rhamnosus GG and VT1 were able to grow with the values higher than 0.6 log CFU.ml-1.h-1 that can be expressed as the times to double (td lower than 0.5 h. This was found in both the amaranth and buckwheat milk-based gruels and water-based amaranth gruels but fermented only by the probiotic GG strain. The 3-week storage tests aimed on survival of the lactobacilli at 6 °C showed minimal decrease of the counts in buckwheat gruels with the average rates of -0.084 and -0.004 log CFU.ml-1.d-1 in water- and milk-based gruels, respectively. On the other hand in amaranth gruels, the numbers of lactobacilli slightly increased with the rate of 0.02 log CFU.ml-1.d-1, on average. The results of this pilot study pointed out that the selection of suitable lactic acid bacteria should be performed for optimal fermentation of pseudo-cereal substrates. The numbers of lactobacilli at the end of fermentation were not or very slightly affected by the type of substrate at 6 °C during three weeks.doi:10.5219/169

  19. GaN growth via HVPE on SiC/Si substrates: growth mechanisms

    Science.gov (United States)

    Sharofidinov, Sh Sh; Redkov, A. V.; Osipov, A. V.; Kukushkin, S. A.

    2017-11-01

    The article focuses on the study of GaN thin film growth via chloride epitaxy on SiC/Si hybrid substrate. SiC buffer layer was grown by a method of substitution of atoms, which allows one to reduce impact of mechanical stress therein on subsequent growth of III-nitride films. It is shown, that change in GaN growth conditions leads to change in its growth mechanism. Three mechanisms: epitaxial, spiral and stepwise growth are considered and mechanical stresses are estimated via Raman spectroscopy.

  20. Graphene growth on Ge(100)/Si(100) substrates by CVD method.

    Science.gov (United States)

    Pasternak, Iwona; Wesolowski, Marek; Jozwik, Iwona; Lukosius, Mindaugas; Lupina, Grzegorz; Dabrowski, Pawel; Baranowski, Jacek M; Strupinski, Wlodek

    2016-02-22

    The successful integration of graphene into microelectronic devices is strongly dependent on the availability of direct deposition processes, which can provide uniform, large area and high quality graphene on nonmetallic substrates. As of today the dominant technology is based on Si and obtaining graphene with Si is treated as the most advantageous solution. However, the formation of carbide during the growth process makes manufacturing graphene on Si wafers extremely challenging. To overcome these difficulties and reach the set goals, we proposed growth of high quality graphene layers by the CVD method on Ge(100)/Si(100) wafers. In addition, a stochastic model was applied in order to describe the graphene growth process on the Ge(100)/Si(100) substrate and to determine the direction of further processes. As a result, high quality graphene was grown, which was proved by Raman spectroscopy results, showing uniform monolayer films with FWHM of the 2D band of 32 cm(-1).

  1. Substrate Dependence of the Freezing Dynamics of Supercooled Water Films: A High-Speed Optical Microscope Study.

    Science.gov (United States)

    Pach, E; Rodriguez, L; Verdaguer, A

    2018-01-18

    The freezing of supercooled water films on different substrates was investigated using a high-speed camera coupled to an optical microscope, obtaining details of the freezing process not described in the literature before. We observed the two well known freezing stages (fast dendritic growth and slow freezing of the water liquid left after the dendritic growth), but we separated the process into different phenomena that were studied separately: two-dimensional dendrite growth on the substrate interface, vertical dendrite growth, formation and evolution of ice domains, trapping of air bubbles and freezing of the water film surface. We found all of these processes to be dependent on both the supercooling temperature and the substrate used. Ice dendrite (or ice front) growth during the first stage was found to be dependent on thermal properties of the substrate but could not be unequivocally related to them. Finally, for low supercooling, a direct relationship was observed between the morphology of the dendrites formed in the first stage, which depends on the substrate, and the roughness and the shape of the surface of the ice, when freezing of the film was completed. This opens the possibility of using surfaces and coatings to control ice morphology beyond anti-icing properties.

  2. The effect of substrate modification on microbial growth on surfaces

    International Nuclear Information System (INIS)

    Brown, Angela Ann

    1998-01-01

    The principle aim of the program was to produce a novel, non-leaching antimicrobial surface for commercial development and future use in the liquid food packaging industry. Antimicrobial surfaces which exist presently have been produced to combat the growth of prokaryotic organisms and usually function as slow release systems. A system which could inhibit eukaryotic growth without contaminating the surrounding 'environment' with the inhibitor was considered of great commercial importance. The remit of this study was concerned with creating a surface which could control the growth of eukaryotic organisms found in fruit juice with particular interest in the yeast, Saccharomyces cerevisiae. Putative antimicrobial surfaces were created by the chemical modification of the test substrate polymers; nylon and ethylvinyl alcohol (EVOH). Surfaces were chemically modified by the covalent coupling of antimicrobial agents known to be active against the yeast Saccharomyces cerevisiae as ascertained by the screening process determining the minimum inhibitory concentration (MIC) values of agents in the desired test medium. During the study it was found that a number of surfaces did appear to inhibit yeast growth in fruit juice, however on further investigation the apparent inhibitory effect was discovered to be the result of un-bound material free in the test medium. On removing the possibility of any un-bound material present on the test surface, by a series of surface washings, the inhibitory effect on yeast growth was eliminated. Of the agents tested only one appeared to have an inhibitory effect which could be attributed to a true antimicrobial surface effect, Amical 48. As there is little known about this agent in the literature, its affect on yeast growth was examined and in particular a proposal for the mode of action on yeast is discussed, providing a plausible explanation for the inhibitory effect observed when this agent is covalently immobilised onto nylon. (author)

  3. Identification of secreted proteins of Aspergillus oryzae associated with growth on solid cereal substrates

    NARCIS (Netherlands)

    Biesebeke, R. te; Boussier, A.; Biezen, N. van; Hondel, C.A.M.J.J. van den; Punt, P.J.

    2006-01-01

    Filamentous growth of Aspergillus oryzae on solid cereal substrates involves secretion of substrate converting enzymes and a solid substrate specific polarised hyphal growth phenotype. To identify proteins produced under these specific conditions, the extracts of A. oryzae grown on wheat-based media

  4. Hydrogen-surfactant-assisted coherent growth of GaN on ZnO substrate

    Science.gov (United States)

    Zhang, Jingzhao; Zhang, Yiou; Tse, Kinfai; Zhu, Junyi

    2018-01-01

    Heterostructures of wurtzite based devices have attracted great research interest because of the tremendous success of GaN in light emitting diodes (LED) industry. High-quality GaN thin films on inexpensive and lattice matched ZnO substrates are both commercially and technologically desirable. Intrinsic wetting conditions, however, forbid such heterostructures as the energy of ZnO polar surfaces is much lower than that of GaN polar surfaces, resulting in 3D growth mode and poor crystal quality. Based on first-principles calculations, we propose the use of surfactant hydrogen to dramatically alter the growth mode of the heterostructures. Stable H-involved surface configurations and interfaces are investigated with the help of our newly developed modelling techniques. The temperature and chemical potential dependence of our proposed strategy, which is critical in experiments, is predicted by applying the experimental Gibbs free energy of H2. Our thermodynamic wetting condition analysis is a crucial step for the growth of GaN on ZnO, and we find that introducing H will not degrade the stability of ZnO substrate. This approach will allow the growth of high-quality GaN thin films on ZnO substrates. We believe that our new strategy may reduce the manufactory cost, improve the crystal quality, and improve the efficiency of GaN-based devices.

  5. Epitaxial growth of ZnO layers on (111) GaAs substrates by laser molecular beam epitaxy

    International Nuclear Information System (INIS)

    Ding Jian; Zhang Di; Konomi, Takaharu; Saito, Katsuhiko; Guo Qixin

    2012-01-01

    ZnO layers were grown on (111) GaAs substrates by laser molecular epitaxy at substrate temperatures between 200 and 550 °C. X-ray diffraction analysis revealed that c-axis of ZnO epilayer with a wurtzite structure is perpendicular to the substrate surface. X-ray rocking curves and Raman spectroscopy showed that the crystal quality of ZnO epilayers depends on the substrate temperature during the growth. Strong near-band-edge emission in the UV region without any deep-level emissions was observed from the ZnO epilayers at room temperature. The results indicate that laser molecular beam epitaxy is a promising growth method for obtaining high-quality ZnO layers on (111) GaAs substrates.

  6. Epidermal growth factor pathway substrate 15, Eps15

    DEFF Research Database (Denmark)

    Salcini, A E; Chen, H; Iannolo, G

    1999-01-01

    Eps15 was originally identified as a substrate for the kinase activity of the epidermal growth factor receptor (EGFR). Eps15 has a tripartite structure comprising a NH2-terminal portion, which contains three EH domains, a central putative coiled-coil region, and a COOH-terminal domain containing...... multiple copies of the amino acid triplet Aspartate-Proline-Phenylalanine. A pool of Eps15 is localized at clathrin coated pits where it interacts with the clathrin assembly complex AP-2 and a novel AP-2 binding protein, Epsin. Perturbation of Eps15 and Epsin function inhibits receptor-mediated endocytosis...... of EGF and transferrin, demonstrating that both proteins are components of the endocytic machinery. Since the family of EH-containing proteins is implicated in various aspects of intracellular sorting, biomolecular strategies aimed at interfering with these processes can now be envisioned...

  7. Substrates of neuropsychological functioning in stimulant dependence: a review of functional neuroimaging research

    NARCIS (Netherlands)

    Crunelle, C.L.; Veltman, D.J.; Booij, J.; van Emmerik-van Oortmerssen, K.; van den Brink, W.

    2012-01-01

    Stimulant dependence is associated with neuropsychological impairments. Here, we summarize and integrate the existing neuroimaging literature on the neural substrates of neuropsychological (dys)function in stimulant dependence, including cocaine, (meth-)amphetamine, ecstasy and nicotine dependence,

  8. Simulation and theory of island growth on stepped substrates

    International Nuclear Information System (INIS)

    Pownall, C.D.

    1999-10-01

    The nucleation, growth and coalescence of islands on stepped substrates is investigated by Monte Carlo simulations and analytical theories. Substrate steps provide a preferential site for the nucleation of islands, making many of the important processes one-dimensional in nature, and are of potentially major importance in the development of low-dimensional structures as a means of growing highly ordered chains of 'quantum dots' or continuous 'quantum wires'. A model is developed in which island nucleation is entirely restricted to the step edge, islands grow in compact morphologies by monomer capture, and eventually coalesce with one another until a single continuous cluster of islands covers the entire step. A series of analytical theories is developed to describe the dynamics of the whole evolution. The initial nucleation and aggregation regimes are modeled using the traditional approach of rate equations, rooted in mean field theory, but incorporating corrections to account for correlations in the nucleation and capture processes. This approach is found to break down close to the point at which the island density saturates and a new approach is developed based upon geometric and probabilistic arguments to describe the saturation behaviour, including the characteristic dynamic scaling which is found to persist through the coalescence regime as well. A further new theory, incorporating arguments based on the geometry of Capture Zones, is presented which reproduces the dynamics of the coalescence regime. The, latter part of the. thesis considers the spatial properties of the system, in particular the spacing of the islands along the step. An expression is derived which describes the distribution of gap sizes, and this is solved using a recently-developed relaxation method. An important result is the discovery that larger critical island sizes tend to yield more evenly spaced arrays of islands. The extent of this effect is analysed by solving for critical island

  9. Rayleigh-Taylor instability under curved substrates: An optimal transient growth analysis

    Science.gov (United States)

    Balestra, Gioele; Brun, P.-T.; Gallaire, François

    2016-12-01

    We investigate the stability of thin viscous films coated on the inside of a horizontal cylindrical substrate. In such a case, gravity acts both as a stabilizing force through the progressive drainage of the film and as a destabilizing force prone to form droplets via the Rayleigh-Taylor instability. The drainage solution, derived from lubrication equations, is found asymptotically stable with respect to infinitesimally small perturbations, although in reality, droplets often form. To resolve this paradox, we perform an optimal transient growth analysis for the first-order perturbations of the liquid's interface, generalizing the results of Trinh et al. [Phys. Fluids 26, 051704 (2014), 10.1063/1.4876476]. We find that the system displays a linear transient growth potential that gives rise to two different scenarios depending on the value of the Bond number (prescribing the relative importance of gravity and surface tension forces). At low Bond numbers, the optimal perturbation of the interface does not generate droplets. In contrast, for higher Bond numbers, perturbations on the upper hemicircle yield gains large enough to potentially form droplets. The gain increases exponentially with the Bond number. In particular, depending on the amplitude of the initial perturbation, we find a critical Bond number above which the short-time linear growth is sufficient to trigger the nonlinear effects required to form dripping droplets. We conclude that the transition to droplets detaching from the substrate is noise and perturbation dependent.

  10. Growth and properties of ZnO films on polymeric substrate by spray pyrolysis method

    Energy Technology Data Exchange (ETDEWEB)

    Kriisa, Merike; Kärber, Erki [Department of Materials Science, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia); Krunks, Malle, E-mail: malle.krunks@ttu.ee [Department of Materials Science, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia); Mikli, Valdek [Centre for Materials Research, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia); Unt, Tarmo; Kukk, Mart; Mere, Arvo [Department of Materials Science, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia)

    2014-03-31

    The growth of ZnO layers deposited by spray pyrolysis on polymeric substrate was studied. Zinc acetate precursor solution was sprayed onto preheated polyimide (PI) and glass reference substrates at 380 °C. The structural, morphological, optical and electrical properties of the layers were measured by X-ray diffraction, scanning electron microscopy, optical spectroscopy and van der Pauw and Hall method. ZnO:In layers could be grown on PI when deposited onto undoped ZnO layer acting as a buffer layer on PI. Independent of the substrate type, the ZnO/ZnO:In bilayer showed a mixed morphology from smooth canvas-like surface to large scrolled belt grains dependent on buffer layer morphology. Due to the formation of scrolled belts, the ZnO:In layer shows no preferential orientation, yet the preferred orientation of the ZnO buffer crystallites is (100) plane parallel to the substrate. The bilayers deposited on PI exhibit high light scattering capability (haze factor of 85–95% in the spectral region of 350–1500 nm). The resistivity of the ZnO:In film in bilayer on PI is 4.4 × 10{sup −2} Ω cm mainly due to low carrier mobility of 1.5 cm{sup 2}/Vs, the carrier concentration is 10{sup 20} cm{sup −3}. - Highlights: • ZnO:In layers were grown on polyimide substrate by spray pyrolysis. • The buffer layer morphology is controlled by the layer thickness and spray rate. • ZnO/ZnO:In bilayer morphology is dependent on the surface of buffer layer. • Rough buffer layer leads to rough bilayer with scrolled belts (diameter of 2–6 μm). • Due to scrolled belts layers show no preferential growth yet highly scatter light.

  11. Microbial uptake of radiolabeled substrates: estimates of growth rates from time course measurements

    International Nuclear Information System (INIS)

    Li, W.K.W.

    1984-01-01

    The uptake of [ 3 H]glucose and a mixture of 3 H-labeled amino acids was measured, in time course fashion, in planktonic microbial assemblages of the eastern tropical Pacific Ocean. The average generation times of those portions of the assemblages able to utilize these substrates were estimated from a simple exponential growth model. Other workers have independently used this model in its integrated or differential form. A mathematical verification and an experimental demonstration of the equivalence of the two approaches are presented. A study was made of the size distribution of heterotrophic activity, using time course measurements. It was found that the size distribution and the effect of sample filtration before radiolabeling were dependent on time of incubation. In principle, it was possible to ascribe these time dependences to differences in th specific growth rate and initial standing stock of the microbial assemblages. 33 references

  12. Substrate engineering for Ni-assisted growth of carbon nano-tubes

    Energy Technology Data Exchange (ETDEWEB)

    Kolahdouz, Z.; Kolahdouz, M. [Department of Electrical and Computer Engineering, Nano-electronic Laboratory, University of Tehran, Tehran (Iran, Islamic Republic of); Ghanbari, H. [Tarbiat Modarres University, Tehran (Iran, Islamic Republic of); Mohajerzadeh, S. [Department of Electrical and Computer Engineering, Nano-electronic Laboratory, University of Tehran, Tehran (Iran, Islamic Republic of); Naureen, S. [School of Information and Communication Technology, KTH (Royal Institute of Technology) Kista (Sweden); Radamson, H.H., E-mail: rad@kth.se [School of Information and Communication Technology, KTH (Royal Institute of Technology) Kista (Sweden)

    2012-10-01

    The growth of carbon multi-walled nano-tubes (MWCNTs) using metal catalyst (e.g. Ni, Co, and Fe) has been extensively investigated during the last decade. In general, the physical properties of CNTs depend on the type, quality and diameter of the tubes. One of the parameters which affects the diameter of a MWCNT is the size of the catalyst metal islands. Considering Ni as the metal catalyst, the formed silicide layer agglomerates (island formation) after a thermal treatment. One way to decrease the size of Ni islands is to apply SiGe as the base for the growth. In this study, different methods based on substrate engineering are proposed to change/control the MWCNT diameters. These include (i) well-controlled oxide openings containing Ni to miniaturize the metal island size, and (ii) growth on strained or partially relaxed SiGe layers for smaller Ni silicide islands.

  13. Single crystalline metal films as substrates for graphene growth

    Energy Technology Data Exchange (ETDEWEB)

    Zeller, Patrick; Henss, Ann-Kathrin; Wintterlin, Joost [Department Chemie, Ludwig-Maximilians-Universitaet Muenchen (Germany); Weinl, Michael; Schreck, Matthias [Institut fuer Physik, Universitaet Augsburg (Germany); Speck, Florian; Ostler, Markus [Lehrstuhl fuer Technische Physik, Universitaet Erlangen-Nuernberg, Erlangen (Germany); Institut fuer Physik, Technische Universitaet Chemnitz (Germany); Seyller, Thomas [Institut fuer Physik, Technische Universitaet Chemnitz (Germany)

    2017-11-15

    Single crystalline metal films deposited on YSZ-buffered Si(111) wafers were investigated with respect to their suitability as substrates for epitaxial graphene. Graphene was grown by CVD of ethylene on Ru(0001), Ir(111), and Ni(111) films in UHV. For analysis a variety of surface science methods were used. By an initial annealing step the surface quality of the films was strongly improved. The temperature treatments of the metal films caused a pattern of slip lines, formed by thermal stress in the films, which, however, did not affect the graphene quality and even prevented wrinkle formation. Graphene was successfully grown on all three types of metal films in a quality comparable to graphene grown on bulk single crystals of the same metals. In the case of the Ni(111) films the originally obtained domain structure of rotational graphene phases could be transformed into a single domain by annealing. This healing process is based on the control of the equilibrium between graphene and dissolved carbon in the film. For the system graphene/Ni(111) the metal, after graphene growth, could be removed from underneath the epitaxial graphene layer by a pure gas phase reaction, using the reaction of CO with Ni to give gaseous Ni(CO){sub 4}. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Substrate-dependent cell elasticity measured by optical tweezers indentation

    Science.gov (United States)

    Yousafzai, Muhammad S.; Ndoye, Fatou; Coceano, Giovanna; Niemela, Joseph; Bonin, Serena; Scoles, Giacinto; Cojoc, Dan

    2016-01-01

    In the last decade, cell elasticity has been widely investigated as a potential label free indicator for cellular alteration in different diseases, cancer included. Cell elasticity can be locally measured by pulling membrane tethers, stretching or indenting the cell using optical tweezers. In this paper, we propose a simple approach to perform cell indentation at pN forces by axially moving the cell against a trapped microbead. The elastic modulus is calculated using the Hertz-model. Besides the axial component, the setup also allows us to examine the lateral cell-bead interaction. This technique has been applied to measure the local elasticity of HBL-100 cells, an immortalized human cell line, originally derived from the milk of a woman with no evidence of breast cancer lesions. In addition, we have studied the influence of substrate stiffness on cell elasticity by performing experiments on cells cultured on two substrates, bare and collagen-coated, having different stiffness. The mean value of the cell elastic modulus measured during indentation was 26±9 Pa for the bare substrate, while for the collagen-coated substrate it diminished to 19±7 Pa. The same trend was obtained for the elastic modulus measured during the retraction of the cell: 23±10 Pa and 13±7 Pa, respectively. These results show the cells adapt their stiffness to that of the substrate and demonstrate the potential of this setup for low-force probing of modifications to cell mechanics induced by the surrounding environment (e.g. extracellular matrix or other cells).

  15. Substrates of neuropsychological functioning in stimulant dependence: a review of functional neuroimaging research

    NARCIS (Netherlands)

    Crunelle, Cleo L.; Veltman, Dick J.; Booij, Jan; Emmerik-van Oortmerssen, Katelijne; den Brink, Wim

    2012-01-01

    Stimulant dependence is associated with neuropsychological impairments. Here, we summarize and integrate the existing neuroimaging literature on the neural substrates of neuropsychological (dys) function in stimulant dependence, including cocaine, (meth-) amphetamine, ecstasy and nicotine

  16. Temperature-dependent evolution of chemisorbed digermane in Ge thin film growth

    International Nuclear Information System (INIS)

    Eres, D.; Sharp, J.W.

    1992-01-01

    The formation and evolution of chemisorbed digermane layers in context with germanium thin film growth was investigated by time- resolved surface reflectometry. Modulation of the source gas supply made possible the separation and independent study of the temperature dependence of the adsorption and desorption processes. The regeneration of active sites by molecular hydrogen desorption was identified as the rate-limiting step at low substrate temperatures. A dynamic method of thin film growth was demonstrated by repetitively replenishing the active film growth sites regenerated between two successive source gas pulses. The film growth rate was shown to be related to the substrate temperature and the delay time between successive source gas pulses

  17. Strawberry Production in Soilless Substrate Troughs – Plant Growth

    Science.gov (United States)

    Soilless substrates made of peat moss, coconut coir, perlite, rockwool or bark are pathogen free and they have been used in strawberry production in Europe in troughs or containers. Open field strawberry production in soilless substrate is new to California growers. The objective of this study was t...

  18. Effects of bamboo substrate and supplementary feed on growth and ...

    African Journals Online (AJOL)

    application as control (C), control and substrate installation (C + S) and, control and substrate with supplementary feeding (C + S + F) were randomly allotted to six earthen ponds each with an area of 100m2. Catfish fingerlings of mean weight 27.5g + 1.25 were stocked at the rate of 80 fish per 100m2. Water temperature, pH ...

  19. Molecular beam epitaxial growth and characterization of GaSb layers on GaAs (0 0 1) substrates

    International Nuclear Information System (INIS)

    Li Yanbo; Zhang Yang; Zhang Yuwei; Wang Baoqiang; Zhu Zhanping; Zeng Yiping

    2012-01-01

    We report on the growth of GaSb layers on GaAs (0 0 1) substrates by molecular beam epitaxy (MBE). We investigate the influence of the GaAs substrate surface treatment, growth temperature, and V/III flux ratios on the crystal quality and the surface morphology of GaSb epilayers. Comparing to Ga-rich GaAs surface preparation, the Sb-rich GaAs surface preparation can promote the growth of higher-quality GaSb material. It is found that the crystal quality, electrical properties, and surface morphology of the GaSb epilayers are highly dependent on the growth temperature, and Sb/Ga flux ratios. Under the optimized growth conditions, we demonstrate the epitaxial growth of high quality GaSb layers on GaAs substrates. The p-type nature of the unintentionally doped GaSb is studied and from the growth conditions dependence of the hole concentrations of the GaSb, we deduce that the main native acceptor in the GaSb is the Ga antisite (Ga Sb ) defect.

  20. Chemically Functionalized Carbon Nanotubes as Substrates for Neuronal Growth

    Science.gov (United States)

    Hu, Hui; Ni, Yingchun; Montana, Vedrana; Haddon, Robert C.; Parpura, Vladimir

    2009-01-01

    We report the use of chemically modified carbon nanotubes as a substrate for cultured neurons. The morphological features of neurons that directly reflect their potential capability in synaptic transmission are characterized. The chemical properties of carbon nanotubes are systematically varied by attaching different functional groups that confer known characteristics to the substrate. By manipulating the charge carried by functionalized carbon nanotubes we are able to control the outgrowth and branching pattern of neuronal processes. PMID:21394241

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

    Energy Technology Data Exchange (ETDEWEB)

    Paloly, Abdul Rasheed; Satheesh, M. [Nano Functional Materials Lab, Department of Physics, Cochin University of Science and Technology, Kochi 682022, Kerala (India); Martínez-Tomás, M. Carmen; Muñoz-Sanjosé, Vicente [Departamento de Física Aplicada y Electromagnetismo, Universitat de Valencia, c/Dr Moliner 50, Burjassot, Valencia 46100 (Spain); Rajappan Achary, Sreekumar [Nano Functional Materials Lab, Department of Physics, Cochin University of Science and Technology, Kochi 682022, Kerala (India); Bushiri, M. Junaid, E-mail: junaidbushiri@gmail.com [Nano Functional Materials Lab, Department of Physics, Cochin University of Science and Technology, Kochi 682022, Kerala (India)

    2015-12-01

    Highlights: • SnO{sub 2} thin films were grown on hydrophilic and hydrophobic glass substrates. • Samples on hydrophobic substrates are having comparatively larger lattice volume. • Films on hydrophobic substrates have larger particles and low density distribution. • Substrate dependent photoluminescence emission is observed and studied. • SnO{sub 2} thin films grown over hydrophobic substrates may find potential applications. - Abstract: In this paper, we have demonstrated the growth of tin oxide (SnO{sub 2}) 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 SnO{sub 2} 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 SnO{sub 2} 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 SnO{sub 2} thin films is attributed to lattice defects formed during the film growth due to the mismatch between the film and the hydrophobic substrate surface.

  2. Outcome dependency alters the neural substrates of impression formation

    Science.gov (United States)

    Ames, Daniel L.; Fiske, Susan T.

    2015-01-01

    How do people maintain consistent impressions of other people when other people are often inconsistent? The present research addresses this question by combining recent neuroscientific insights with ecologically meaningful behavioral methods. Participants formed impressions of real people whom they met in a personally involving situation. fMRI and supporting behavioral data revealed that outcome dependency (i.e., depending on another person for a desired outcome) alters previously identified neural dynamics of impression formation. Consistent with past research, a functional localizer identified a region of dorsomedial PFC previously linked to social impression formation. In the main task, this ROI revealed the predicted patterns of activity across outcome dependency conditions: greater BOLD response when information confirmed (vs. violated) social expectations if participants were outcome-independent and the reverse pattern if participants were outcome-dependent. We suggest that, although social perceivers often discount expectancy-disconfirming information as noise, being dependent on another person for a desired outcome focuses impression-formation processing on the most diagnostic information, rather than on the most tractable information. PMID:23850465

  3. Substrate bias voltage and deposition temperature dependence on ...

    Indian Academy of Sciences (India)

    Thin films or a coating of any sort prior to its application into real world has to be studied for the dependence of ..... For line focusing, incident beam mask was employed with ..... org/content/avs/journal/jvst/11/4/10.1116/1.1312732. Thornton J A ...

  4. Correlation between substrate bias, growth process and structural properties of phosphorus incorporated tetrahedral amorphous carbon films

    International Nuclear Information System (INIS)

    Liu Aiping; Zhu Jiaqi; Han Jiecai; Wu Huaping; Jia Zechun

    2007-01-01

    We investigate the growth process and structural properties of phosphorus incorporated tetrahedral amorphous carbon (ta-C:P) films which are deposited at different substrate biases by filtered cathodic vacuum arc technique with PH 3 as the dopant source. The films are characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy, Raman spectroscopy, residual stress measurement, UV/VIS/NIR absorption spectroscopy and temperature-dependent conductivity measurement. The atomic fraction of phosphorus in the films as a function of substrate bias is obtained by XPS analysis. The optimum bias for phosphorus incorporation is about -80 V. Raman spectra show that the amorphous structures of all samples with atomic-scaled smooth surface are not remarkably changed when PH 3 is implanted, but some small graphitic crystallites are formed. Moreover, phosphorus impurities and higher-energetic impinging ions are favorable for the clustering of sp 2 sites dispersed in sp 3 skeleton and increase the level of structural ordering for ta-C:P films, which further releases the compressive stress and enhances the conductivity of the films. Our analysis establishes an interrelationship between microstructure, stress state, electrical properties, and substrate bias, which helps to understand the deposition mechanism of ta-C:P films

  5. Calcium-Dependent Protein Kinases from Arabidopsis show substrate specificity differences in an analysis of 103 substrates

    Directory of Open Access Journals (Sweden)

    Amy eCurran

    2011-08-01

    Full Text Available The identification of substrates represents a critical challenge for understanding any protein kinase-based signal transduction pathway. In Arabidopsis, there are more than 1000 different protein kinases, 34 of which belong to a family of Ca2+-dependent protein kinases (CPKs. While CPKs are implicated in regulating diverse aspects of plant biology, from ion transport to transcription, relatively little is known about isoform-specific differences in substrate specificity, or the number of phosphorylation targets. Here, in vitro kinase assays were used to compare phosphorylation targets of four CPKs from Arabidopsis (CPK1, 10, 16 and 34. Significant differences in substrate specificity for each kinase were revealed by assays using 103 different substrates. For example CPK16 phosphorylated Serine 109 in a peptide from the stress-regulated protein, Di19-2 with KM ~70 µM, but this site was not phosphorylated significantly by CPKs 1, 10, or 34. In contrast, CPKs 1, 10, and 34 phosphorylated 93 other peptide substrates not recognized by CPK16. Examples of substrate specificity differences among all four CPKs were verified by kinetic analyses. To test the correlation between in vivo phosphorylation events and in vitro kinase activities, assays were performed with 274 synthetic peptides that contained phosphorylation sites previously mapped in proteins isolated from plants (in vivo-mapped sites. Of these, 74 (27% were found to be phosphorylated by at least one of the four CPKs tested. This 27% success rate validates a robust strategy for linking the activities of specific kinases, such as CPKs, to the thousands of in planta phosphorylation sites that are being uncovered by emerging technologies.

  6. Substrate dependent morphologies of self-assembled nanocrystalline manganite films: An atomic force microscopy study

    International Nuclear Information System (INIS)

    Kale, S.N.; Mona, J.; Ganesan, V.; Choudhary, R.J.; Phase, D.M.

    2009-06-01

    Thin films of La 0 .7Sr 0 .3MnO 3 (LSMO) have been deposited on different substrates: Si (001), Al 2 O 3 (AlO) (0001) and LaAlO 3 (LAO) (001), using a pulsed laser deposition system. 100 nm films have been deposited at substrate temperature of 700 deg C and oxygen partial pressure of 400 mTorr. X-Ray diffraction analysis shows a polycrystalline growth of both layers on Si and Al 2 O 3 substrates, while a c-axis oriented growth on LAO substrate. Atomic force microscopy images exhibit interesting island-like morphology of grain size ∼ 250 nm on Si substrate. Similar morphology with much smaller (∼ 150 nm), closely packed islands are seen to grow on AlO substrate. Films on LAO show comparatively a smooth morphology with the grains size less than 100 nm, decorated by characteristic depressions at the grain boundaries. The formation of self-assembled nanostructures can be understood on the basis of film-substrate lattice misfit, strains in the systems and eventual growth of the films to attain energy minimization (author)

  7. AlGaInAs narrow stripe selective growth on substrates patterned with different mask designs

    International Nuclear Information System (INIS)

    Feng, W; Pan, J Q; Yang, H; Hou, L P; Zhou, F; Zhao, L J; Zhu, H L; Wang, W

    2006-01-01

    We have performed a narrow stripe selective growth of oxide-free AlGaInAs waveguides on InP substrates patterned with pairs of SiO 2 mask stripes under optimized growth conditions. The mask stripe width varied from 0 to 40 μm, while the window region width between a pair of mask stripes was fixed at 1.5, 2.5 or 3.5 μm. Flat and smooth AlGaInAs waveguides covered by specific InP layers are successfully grown on substrates patterned with different mask designs. The thickness enhancement ratio and the photoluminescence (PL) spectrum of the AlGaInAs narrow stripe waveguides are strongly dependent on the mask stripe width and the window region width. In particular, a large PL wavelength shift of 79 nm and a PL FWHM of less than 64 meV are obtained simultaneously with a small mask stripe width varying from 0 to 40 μm when the window region width is 1.5 μm. We present some possible interpretations of the experimental observations in considering both the migration effect from a masked region and the lateral vapour diffusion effect

  8. High-yield growth of vertically aligned carbon nanotubes on a continuously moving substrate

    International Nuclear Information System (INIS)

    Guzman de Villoria, R; Hart, A J; Steiner, S A III; Wardle, B L; Figueredo, S L; Slocum, A H

    2009-01-01

    Vertically aligned carbon nanotube (CNT) arrays are grown on a moving substrate, demonstrating continuous growth of nanoscale materials with long-range order. A cold-wall chamber with an oscillating moving platform is used to locally heat a silicon growth substrate coated with an Fe/Al 2 O 3 catalyst film for CNT growth via chemical vapor deposition. The reactant gases are introduced over the substrate through a directed nozzle to attain high-yield CNT growth. Aligned multi-wall carbon nanotube arrays (or 'forests') with heights of ∼1 mm are achieved at substrate speeds up to 2.4 mm s -1 . Arrays grown on moving substrates at different velocities are studied in order to identify potential physical limitations of repeatable and fast growth on a continuous basis. No significant differences are noted between static and moving growth as characterized by scanning electron microscopy and Raman spectroscopy, although overall growth height is marginally reduced at the highest substrate velocity. CNT arrays produced on moving substrates are also found to be comparable to those produced through well-characterized batch processes consistent with a base-growth mechanism. Growth parameters required for the moving furnace are found to differ only slightly from those used in a comparable batch process; thermal uniformity appears to be the critical parameter for achieving large-area uniform array growth. If the continuous-growth technology is combined with a reaction zone isolation scheme common in other types of processing (e.g., in the manufacture of carbon fibers), large-scale dense and aligned CNT arrays may be efficiently grown and harvested for numerous applications including providing interlayers for advanced composite reinforcement and improved electrical and thermal transport.

  9. High-yield growth of vertically aligned carbon nanotubes on a continuously moving substrate.

    Science.gov (United States)

    Guzmán de Villoria, R; Figueredo, S L; Hart, A J; Steiner, S A; Slocum, A H; Wardle, B L

    2009-10-07

    Vertically aligned carbon nanotube (CNT) arrays are grown on a moving substrate, demonstrating continuous growth of nanoscale materials with long-range order. A cold-wall chamber with an oscillating moving platform is used to locally heat a silicon growth substrate coated with an Fe/Al2O3 catalyst film for CNT growth via chemical vapor deposition. The reactant gases are introduced over the substrate through a directed nozzle to attain high-yield CNT growth. Aligned multi-wall carbon nanotube arrays (or 'forests') with heights of approximately 1 mm are achieved at substrate speeds up to 2.4 mm s(-1). Arrays grown on moving substrates at different velocities are studied in order to identify potential physical limitations of repeatable and fast growth on a continuous basis. No significant differences are noted between static and moving growth as characterized by scanning electron microscopy and Raman spectroscopy, although overall growth height is marginally reduced at the highest substrate velocity. CNT arrays produced on moving substrates are also found to be comparable to those produced through well-characterized batch processes consistent with a base-growth mechanism. Growth parameters required for the moving furnace are found to differ only slightly from those used in a comparable batch process; thermal uniformity appears to be the critical parameter for achieving large-area uniform array growth. If the continuous-growth technology is combined with a reaction zone isolation scheme common in other types of processing (e.g., in the manufacture of carbon fibers), large-scale dense and aligned CNT arrays may be efficiently grown and harvested for numerous applications including providing interlayers for advanced composite reinforcement and improved electrical and thermal transport.

  10. Onset temperature for Si nanostructure growth on Si substrate during high vacuum electron beam annealing.

    Science.gov (United States)

    Fang, F; Markwitz, A

    2009-05-01

    Silicon nanostructures, called Si nanowhiskers, are successfully synthesized on Si(100) substrate by high vacuum electron beam annealing. The onset temperature and duration needed for the Si nanowhiskers to grow was investigated. It was found that the onset and growth morphology of Si nanowhiskers strongly depend on the annealing temperature and duration applied in the annealing cycle. The onset temperature for nanowhisker growth was determined as 680 degrees C using an annealing duration of 90 min and temperature ramps of +5 degrees C s(-1) for heating and -100 degrees C s(-1) for cooling. Decreasing the annealing time at peak temperature to 5 min required an increase in peak temperature to 800 degrees C to initiate the nanowhisker growth. At 900 degrees C the duration for annealing at peak temperature can be set to 0 s to grow silicon nanowhiskers. A correlation was found between the variation in annealing temperature and duration and the nanowhisker height and density. Annealing at 900 degrees C for 0 s, only 2-3 nanowhiskers (average height 2.4 nm) grow on a surface area of 5 x 5 microm, whereas more than 500 nanowhiskers with an important average height of 4.6 nm for field emission applications grow on the same surface area for a sample annealed at 970 degrees C for 0 s. Selected results are presented showing the possibility of controlling the density and height of Si nanowhisker growth for field emission applications by applying different annealing temperature and duration.

  11. Germanium growth on electron beam lithography patterned Si3N4/Si(001) substrate using molecular beam epitaxy

    Science.gov (United States)

    Sarkar, Subhendu Sinha; Katiyar, Ajit K.; Sarkar, Arijit; Dhar, Achintya; Rudra, Arun; Khatri, Ravinder K.; Ray, Samit Kumar

    2018-04-01

    It is important to investigate the growth dynamics of Ge adatoms under different surface stress regimes of the patterned dielectric to control the selective growth of self-assembled Ge nanostructures on silicon. In the present work, we have studied the growth of Ge by molecular beam epitaxy on nanometer scale patterned Si3N4/Si(001) substrates generated using electron beam lithography. The pitch of the patterns has been varied to investigate its effect on the growth of Ge in comparison to un-patterned Si3N4. For the patterned Si3N4 film, Ge did not desorbed completely from the Si3N4 film and hence no site selective growth pattern is observed. Instead, depending upon the pitch, Ge growth has occurred in different growth modes around the openings in the Si3N4. For the un-patterned substrate, the morphology exhibits the occurrence of uniform 3D clustering of Ge adatoms on Si3N4 film. This variation in the growth modes of Ge is attributed to the variation of residual stress in the Si3N4 film for different pitch of holes, which has been confirmed theoretically through Comsol Multiphysics simulation. The variation in stress for different pitches resulted in modulation of surface energy of the Si3N4 film leading to the different growth modes of Ge.

  12. Experimental Results and Integrated Modeling of Bacterial Growth on an Insoluble Hydrophobic Substrate (Phenanthrene)

    DEFF Research Database (Denmark)

    Adam, Iris K. U.; Rein, Arno; Miltner, Anja

    2014-01-01

    Metabolism of a low-solubility substrate is limited by dissolution and availability and can hardly be determined. We developed a numerical model for simultaneously calculating dissolution kinetics of such substrates and their metabolism and microbial growth (Monod kinetics with decay) and tested ...

  13. Growth of fullerene on Ag and hydrogen-passivated Si substrates: Effect of electron beam exposure on growth modes

    International Nuclear Information System (INIS)

    Rundhe, M.V.; Dev, B.N.

    2008-01-01

    We have used Auger electron spectroscopy (AES) to investigate the effect of electron beam exposure on growth modes of fullerene (C 60 ) on substrates like Ag and hydrogen-passivated Si(1 1 1). The electron beam comprises of 3.4 keV electrons, which are used in the AES study. To investigate the effect, Auger signal (AS) vs. deposition time (t) measurements were conducted in a sequential mode, i.e., alternating deposition of C 60 and analysis using the electron beam. Duration of AES data collection after each deposition was the duration of exposure to electron beam in this experiment. For the growth study of C 60 on Ag, three AS-t plots were recorded for three different durations of exposure to electron beam. Changes in the AS-t plot, depending on the duration of exposure to the electron beam, reflect the electron beam-induced damage. Electron beam-induced damages of C 60 produce carbon materials of different densities and consequently transmission coefficient (α) of Auger electron through this material changes. In order to fit the AES (AS vs. t) data a model has been used which simultaneously provides the growth mode and the transmission coefficient. Observation of an increasing transmission coefficient with the increasing duration of exposure to the electron beam from α=0.34 to 0.60 indicates the change of the nature of the carbon material due to the partial damage of C 60

  14. Influence of substrate temperature, growth rate and TCO substrate on the properties of CSS deposited CdS thin films

    Energy Technology Data Exchange (ETDEWEB)

    Schaffner, J., E-mail: jschaffner@surface.tu-darmstadt.de; Feldmeier, E.; Swirschuk, A.; Schimper, H.-J.; Klein, A.; Jaegermann, W.

    2011-08-31

    The growth of CdS thin films by close space sublimation (CSS) has been systematically studied using an ultra-high vacuum system known as DAISY-SOL in order to understand the basic growth mechanisms and their impact on the film properties. Substrate temperature and deposition rate were varied, and the surface properties of the CdS layer were determined by photoelectron spectroscopy (XPS) without breaking the vacuum. To analyze the influence of the deposition conditions on the layer morphology and crystallographic structure, the films were further characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The SEM and AFM studies show a correlation between the deposition rate and the film morphology. For high deposition rates, edged grain shapes and smoother surfaces were observed than for low deposition rates. CdS films were deposited onto two different commercially available fluorine-doped tin oxide (FTO) substrates. XRD studies show that a high <200> texture of the FTO substrate prefers the CdS growth in <0001> orientation of the hexagonal crystal modification.

  15. Effects of mixed substrates on growth and vitamin production by ...

    African Journals Online (AJOL)

    The effects of mixed carbon sources on growth and production of vitamins E and A by Euglena gracilis cells were investigated in batch culture. The cells were grown mixotrophically in glucose (G), ethanol (E) and a mixture of glucose and ethanol (EG). Cell growth was measured by counting the cell number with microscope, ...

  16. Logistic growth models of China pinks, cultivated on seven substrates, as a function of degree days

    Directory of Open Access Journals (Sweden)

    Marília Milani

    Full Text Available ABSTRACT: The objective of this study was to characterize the height (H and leaf number (LN of China pinks, grown in seven substrates, as a function of degree days, using the logistic growth model. H and LN were measured from 56 plants per substrate, for 392 plants in total. Plants that were grown on substrates formed of 50% soil with 50% rice husk ash (50% S + 50% RH and 80% rice husk ash with 20% worm castings (80% RH + 20% W had the longest vegetative growth period (74d, corresponding to 1317.9ºCd. The logistic growth model, adjusted for H, showed differences in the estimation of maximum expected height (α between the substrates, with values between 10.47cm for 50% S + 50% RH and 35.75cm for Mecplant(r. When α was estimated as LN, variation was also observed between the different substrates, from approximately 30 leaves on plants growing on 50% S + 50% RH to 34 leaves on the plants growing on the substrate formed of 80% RH + 20% W. Growth of China pinks can be characterized using H or LN in the logistic growth model as a function of degree days, being the provided plants adequately fertilized. The best substrates in terms of maximum height and leaf number were 80% soil + 20% worm castings and Mecplant(r. However, users must recalibrate the model with the estimated parameters before applying it to different growing conditions.

  17. Vertical epitaxial wire-on-wire growth of Ge/Si on Si(100) substrate.

    Science.gov (United States)

    Shimizu, Tomohiro; Zhang, Zhang; Shingubara, Shoso; Senz, Stephan; Gösele, Ulrich

    2009-04-01

    Vertically aligned epitaxial Ge/Si heterostructure nanowire arrays on Si(100) substrates were prepared by a two-step chemical vapor deposition method in anodic aluminum oxide templates. n-Butylgermane vapor was employed as new safer precursor for Ge nanowire growth instead of germane. First a Si nanowire was grown by the vapor liquid solid growth mechanism using Au as catalyst and silane. The second step was the growth of Ge nanowires on top of the Si nanowires. The method presented will allow preparing epitaxially grown vertical heterostructure nanowires consisting of multiple materials on an arbitrary substrate avoiding undesired lateral growth.

  18. Impact of the silicon substrate resistivity and growth condition on the deep levels in Ni-Au/AlN/Si MIS Capacitors

    Science.gov (United States)

    Wang, Chong; Simoen, Eddy; Zhao, Ming; Li, Wei

    2017-10-01

    Deep levels formed under different growth conditions of a 200 nm AlN buffer layer on B-doped Czochralski Si(111) substrates with different resistivity were investigated by deep-level transient spectroscopy (DLTS) on metal-insulator-semiconductor capacitors. Growth-temperature-dependent Al diffusion in the Si substrate was derived from the free carrier density obtained by capacitance-voltage measurement on samples grown on p- substrates. The DLTS spectra revealed a high concentration of point and extended defects in the p- and p+ silicon substrates, respectively. This indicated a difference in the electrically active defects in the silicon substrate close to the AlN/Si interface, depending on the B doping concentration.

  19. Peroxisomal catalase deficiency modulates yeast lifespan depending on growth conditions

    NARCIS (Netherlands)

    Kawalek, Adam; Lefevre, Sophie D.; Veenhuis, Marten; van der Klei, Ida J.

    We studied the role of peroxisomal catalase in chronological aging of the yeast Hansenula polymorpha in relation to various growth substrates. Catalase-deficient (cat) cells showed a similar chronological life span (CLS) relative to the wild-type control upon growth on carbon and nitrogen sources

  20. Effect of Growth Pressure on Epitaxial Graphene Grown on 4H-SiC Substrates by Using Ethene Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Shuxian Cai

    2015-08-01

    Full Text Available The Si(0001 face and C(000-1 face dependences on growth pressure of epitaxial graphene (EG grown on 4H-SiC substrates by ethene chemical vapor deposition (CVD was studied using atomic force microscopy (AFM and micro-Raman spectroscopy (μ-Raman. AFM revealed that EGs on Si-faced substrates had clear stepped morphologies due to surface step bunching. However, This EG formation did not occur on C-faced substrates. It was shown by μ-Raman that the properties of EG on both polar faces were different. EGs on Si-faced substrates were relatively thinner and more uniform than on C-faced substrates at low growth pressure. On the other hand, D band related defects always appeared in EGs on Si-faced substrates, but they did not appear in EG on C-faced substrate at an appropriate growth pressure. This was due to the μ-Raman covering the step edges when measurements were performed on Si-faced substrates. The results of this study are useful for optimized growth of EG on polar surfaces of SiC substrates.

  1. Kinetic models of cell growth, substrate utilization and bio ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-05-02

    May 2, 2008 ... Aspergillus fumigatus. A simple model was proposed using the Logistic Equation for the growth, ... costs and also involved in less sophisticated fermentation ... apply and they are accurately proved that the model can express ...

  2. Catalyst free growth of CNTs by CVD on nanoscale rough surfaces of silicon substrates

    Science.gov (United States)

    Damodar, D.; Sahoo, R. K.; Jacob, C.

    2013-06-01

    Catalyst free growth of carbon nanotubes (CNT) has been achieved using atmospheric pressure chemical vapor deposition (APCVD) on surface modified Si(111) substrates. The effect of the substrate surface has been observed by partially etching with KOH (potassium hydroxide) solution which is an anisotropic etchant. Scanning electron microscopy (SEM) confirmed the formation of CNTs over most of the area of the substrate where substrates were anisotropically etched. Transmission electron microscopy (TEM) was used to observe the internal structure of the CNTs. Raman spectroscopy further confirmed the formation of the carbon nanostructures and also their graphitic crystallinity.

  3. New Crystal-Growth Methods for Producing Lattice-Matched Substrates for High-Temperature Superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Boatner, L.A.

    2008-06-24

    This effort addressed the technical problem of identifying and growing, on a commercial scale, suitable single-crystal substrates for the subsequent deposition of epitaxial thin films of high temperature semiconductors such as GaN/AlN. The lack of suitable lattice-matched substrate materials was one of the major problem areas in the development of semiconducting devices for use at elevated temperatures as well as practical opto-electronic devices based on Al- and GaN technology. Such lattice-matched substrates are necessary in order to reduce or eliminate high concentrations of defects and dislocations in GaN/AlN and related epitaxial thin films. This effort concentrated, in particular, on the growth of single crystals of ZnO for substrate applications and it built on previous ORNL experience in the chemical vapor transport growth of large single crystals of zinc oxide. This combined expertise in the substrate growth area was further complemented by the ability of G. Eres and his collaborators to deposit thin films of GaN on the subject substrates and the overall ORNL capability for characterizing the quality of such films. The research effort consisted of research on the growth of two candidate substrate materials in conjunction with concurrent research on the growth and characterization of GaN films, i.e. the effort combined bulk crystal growth capabilities in the area of substrate production at both ORNL and the industrial partner, Commercial Crystal Growth Laboratories (CCL), Naples, Florida, with the novel thin-film deposition techniques previously developed in the ORNL SSD.

  4. WhiB6 is required for the secretion-dependent regulation of ESX-1 substrates in pathogenic mycobacteria.

    KAUST Repository

    Abdallah, Abdallah

    2018-04-09

    The mycobacterial type VII secretion system ESX-1 is responsible for the secretion of a number of proteins that play important roles during host infection. The regulation of the expression of secreted proteins is often essential to establish successful infection. Using transcriptome sequencing, we found that the abrogation of ESX-1 function in Mycobacterium marinum leads to a pronounced increase in gene expression levels of the espA operon during the infection of macrophages, suggesting an important role in ESX-1-mediated virulence during the early phase of infection. In addition, the disruption of ESX-1-mediated protein secretion also leads to a specific down-regulation of the ESX-1 substrates, but not of the structural components of this system, during growth in culture medium. This effect is observed in both M. marinum and M. tuberculosis. We established that down-regulation of ESX-1 substrates is the result of a regulatory process that is influenced by the putative transcriptional regulator whib6, which is located adjacent to the esx-1 locus. In addition, the overexpression of the ESX-1-associated PE35/PPE68 protein pair resulted in a significantly increased secretion of the ESX-1 substrate EsxA, demonstrating a functional link between these proteins. Taken together, these data show that WhiB6 is required for the secretion-dependent regulation of ESX-1 substrates and that ESX-1 substrates are regulated independently from the structural components, both during infection and as a result of active secretion.

  5. WhiB6 is required for the secretion-dependent regulation of ESX-1 substrates in pathogenic mycobacteria.

    KAUST Repository

    Abdallah, Abdallah; Weerdenburg, Eveline; Guan, Qingtian; Ummels, Roy; Borggreve, S; Adroub, Sabir; Malas, Tareq; Naeem, Raeece; Zhang, Huoming; Otto, Thomas; Bitter, Wilbert; Pain, Arnab

    2018-01-01

    The mycobacterial type VII secretion system ESX-1 is responsible for the secretion of a number of proteins that play important roles during host infection. The regulation of the expression of secreted proteins is often essential to establish successful infection. Using transcriptome sequencing, we found that the abrogation of ESX-1 function in Mycobacterium marinum leads to a pronounced increase in gene expression levels of the espA operon during the infection of macrophages, suggesting an important role in ESX-1-mediated virulence during the early phase of infection. In addition, the disruption of ESX-1-mediated protein secretion also leads to a specific down-regulation of the ESX-1 substrates, but not of the structural components of this system, during growth in culture medium. This effect is observed in both M. marinum and M. tuberculosis. We established that down-regulation of ESX-1 substrates is the result of a regulatory process that is influenced by the putative transcriptional regulator whib6, which is located adjacent to the esx-1 locus. In addition, the overexpression of the ESX-1-associated PE35/PPE68 protein pair resulted in a significantly increased secretion of the ESX-1 substrate EsxA, demonstrating a functional link between these proteins. Taken together, these data show that WhiB6 is required for the secretion-dependent regulation of ESX-1 substrates and that ESX-1 substrates are regulated independently from the structural components, both during infection and as a result of active secretion.

  6. Simulation study of temperature-dependent diffusion behaviors of Ag/Ag(001) at low substrate temperature

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Danyun; Mo, Yunjie [State Key Laboratory of Optoelectronic Materials and Technologies, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou, 510275 (China); Feng, Xiaofang [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou, 510275 (China); He, Yingyou [State Key Laboratory of Optoelectronic Materials and Technologies, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou, 510275 (China); Jiang, Shaoji, E-mail: stsjsj@mail.sysu.edu.cn [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou, 510275 (China)

    2017-06-01

    Highlights: • The model of combinations of nearest-neighbor atoms of adatom was built to calculate the diffusion barrier of every configuration for Ag/Ag(001). • The complete potential energy curve of a specific diffusion path on the surface was worked out with the help of elementary diffusion behaviors. • The non-monotonic relation between the surface roughness and the substrate temperature (decreasing from 300 K to 100 K) was demonstrated. • A theoretical explanation of diffusion mechanism for the non-monotonic variation of roughness at low substrate temperature was presented. - Abstract: In this study, a model based on the First Principles calculations and Kinetic Monte Carlo simulation were established to study the growth characteristic of Ag thin film at low substrate temperature. On the basis of the interaction between the adatom and nearest-neighbor atoms, some simplifications and assumptions were made to categorize the diffusion behaviors of Ag adatoms on Ag(001). Then the barriers of all possible diffusion behaviors were calculated using the Climbing Image Nudged Elastic Band method (CI-NEB). Based on the Arrhenius formula, the morphology variation, which is attributed to the surface diffusion behaviors during the growth, was simulated with a temperature-dependent KMC model. With this model, a non-monotonic relation between the surface roughness and the substrate temperature (decreasing from 300 K to 100 K) were discovered. The analysis of the temperature dependence on diffusion behaviors presents a theoretical explanation of diffusion mechanism for the non-monotonic variation of roughness at low substrate temperature.

  7. Simulation study of temperature-dependent diffusion behaviors of Ag/Ag(001) at low substrate temperature

    International Nuclear Information System (INIS)

    Cai, Danyun; Mo, Yunjie; Feng, Xiaofang; He, Yingyou; Jiang, Shaoji

    2017-01-01

    Highlights: • The model of combinations of nearest-neighbor atoms of adatom was built to calculate the diffusion barrier of every configuration for Ag/Ag(001). • The complete potential energy curve of a specific diffusion path on the surface was worked out with the help of elementary diffusion behaviors. • The non-monotonic relation between the surface roughness and the substrate temperature (decreasing from 300 K to 100 K) was demonstrated. • A theoretical explanation of diffusion mechanism for the non-monotonic variation of roughness at low substrate temperature was presented. - Abstract: In this study, a model based on the First Principles calculations and Kinetic Monte Carlo simulation were established to study the growth characteristic of Ag thin film at low substrate temperature. On the basis of the interaction between the adatom and nearest-neighbor atoms, some simplifications and assumptions were made to categorize the diffusion behaviors of Ag adatoms on Ag(001). Then the barriers of all possible diffusion behaviors were calculated using the Climbing Image Nudged Elastic Band method (CI-NEB). Based on the Arrhenius formula, the morphology variation, which is attributed to the surface diffusion behaviors during the growth, was simulated with a temperature-dependent KMC model. With this model, a non-monotonic relation between the surface roughness and the substrate temperature (decreasing from 300 K to 100 K) were discovered. The analysis of the temperature dependence on diffusion behaviors presents a theoretical explanation of diffusion mechanism for the non-monotonic variation of roughness at low substrate temperature.

  8. The effect of clay amendment on substrate properties and growth of woody plants

    Directory of Open Access Journals (Sweden)

    Tomáš Meisl

    2012-01-01

    Full Text Available This work deals with the effect of two clay products differing in particle size distribution on properties of growing substrate and on growth of containerized woody plants in substrates amended with these clay products. Fine and coarse clay were added to a peat substrate, each at two rates. The peat substrate without clay was used as a control. The substrates were tested in experiments with two woody ornamentals (Thuja occidentalis ’Smaragd’ and Prunus cistena. Chemical and physical properties of the substrates were measured according to European Standards before planting. Proportion of water categories differing in availability to the plants were calculated from retention curves measured on the sand box. Properties of substrates in containers with and without plants were evaluated in the same way at the end of the culture. Clay addition changed chemical and physical properties of the tested substrates in terms: available nutrients content, particle density, bulk density, total pore volume, easy available water, water buffering capacity, air capacity, and shrinkage. The effect of fine clay was much stronger. In comparison with the clear effect of clay addition on the substrate chemical and physical properties, the effect on the growth and quality of model woody plants was not so explicit.

  9. Cell-substrate interaction with cell-membrane-stress dependent adhesion.

    Science.gov (United States)

    Jiang, H; Yang, B

    2012-01-10

    Cell-substrate interaction is examined in a two-dimensional mechanics model. The cell and substrate are treated as a shell and an elastic solid, respectively. Their interaction through adhesion is treated using nonlinear springs. Compared to previous cell mechanics models, the present model introduces a cohesive force law that is dependent not only on cell-substrate distance but also on internal cell-membrane stress. It is postulated that a living cell would establish focal adhesion sites with density dependent on the cell-membrane stress. The formulated mechanics problem is numerically solved using coupled finite elements and boundary elements for the cell and the substrate, respectively. The nodes in the adhesion zone from either side are linked by the cohesive springs. The specific cases of a cell adhering to a homogeneous substrate and a heterogeneous bimaterial substrate are examined. The analyses show that the substrate stiffness affects the adhesion behavior significantly and regulates the direction of cell adhesion, in good agreement with the experimental results in the literature. By introducing a reactive parameter (i.e., cell-membrane stress) linking biological responses of a living cell to a mechanical environment, the present model offers a unified mechanistic vehicle for characterization and prediction of living cell responses to various kinds of mechanical stimuli including local extracellular matrix and neighboring cells. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. New phenomena in epitaxial growth: solid films on quasicrystalline substrates

    International Nuclear Information System (INIS)

    Fournee, V; Thiel, P A

    2005-01-01

    An overview is given of the research conducted in the field of solid film growth on quasiperiodic surfaces. An atomistic description of quasicrystalline surfaces is presented and discussed in relation to bulk structural models. The various systems for which thin film growth has been attempted so far are reviewed. Emphasis is placed on the nucleation mechanisms of the solid films, on their growth modes in relation to the nature of the deposited metals, on the possibility of intermixing or alloying at the interface and on the epitaxial relationships at the crystal-quasicrystal interfaces. We also describe situations where the deposited elements adopt a quasiperiodic structure, which opens up the possibility of extending our understanding of the relation between quasiperiodicity and the physical properties of such structurally and chemically complex solids. (topical review)

  11. Time dependency of morphological remodeling of endothelial cells in response to substrate stiffness

    Science.gov (United States)

    Goli-Malekabadi, Zahra; Tafazzoli-shadpour, Mohammad; Tamayol, Ali; Seyedjafari, Ehsan

    2017-01-01

    Introduction: Substrate stiffness regulates cellular behavior as cells experience different stiffness values of tissues in the body. For example, endothelial cells (ECs) covering the inner layer of blood vessels are exposed to different stiffness values due to various pathologic and physiologic conditions. Despite numerous studies, cells by time span sense mechanical properties of the substrate, but the response is not well understood. We hypothesized that time is a major determinant influencing the behavior of cells seeded on substrates of varying stiffness. Methods: We monitored cell spreading, internal structure, 3D topography, and the viability of ECs over 24 hours of culture on polydimethylsiloxane (PDMS) substrates with two different degrees of elastic modulus. Results: Despite significant differences in cell spreading after cell seeding, cells showed a similar shape and internal structure after 24 hours of culture on both soft and stiff substrates. However, 3D topographical images confirmed existence of rich lamellipodia and filopodia around the cells cultured on stiffer PDMS substrates. Conclusion: It was concluded that the response of ECs to the substrate stiffness was time dependent with initial enhanced cellular spreading and viability on stiffer substrates. Results can provide a better comprehension of cell mechanotransduction for tissue engineering applications. PMID:28546952

  12. Thickness-controlled direct growth of nanographene and nanographite film on non-catalytic substrates

    Science.gov (United States)

    Du, Lei; Yang, Liu; Hu, Zhiting; Zhang, Jiazhen; Huang, Chunlai; Sun, Liaoxin; Wang, Lin; Wei, Dacheng; Chen, Gang; Lu, Wei

    2018-05-01

    Metal-catalyzed chemical vapor deposition (CVD) has been broadly employed for large-scale production of high-quality graphene. However, a following transfer process to targeted substrates is needed, which is incompatible with current silicon technology. We here report a new CVD approach to form nanographene and nanographite films with accurate thickness control directly on non-catalytic substrates such as silicon dioxide and quartz at 800 °C. The growth time is as short as a few seconds. The approach includes using 9-bis(diethylamino)silylanthracene as the carbon source and an atomic layer deposition (ALD) controlling system. The structure of the formed nanographene and nanographite films were characterized using atomic force microscopy, high resolution transmission electron microscopy, Raman scattering, and x-ray photoemission spectroscopy. The nanographite film exhibits a transmittance higher than 80% at 550 nm and a sheet electrical resistance of 2000 ohms per square at room temperature. A negative temperature-dependence of the resistance of the nanographite film is also observed. Moreover, the thickness of the films can be precisely controlled via the deposition cycles using an ALD system, which promotes great application potential for optoelectronic and thermoelectronic-devices.

  13. Effect of Substrate Morphology on Growth and Field Emission Properties of Carbon Nanotube Films

    Directory of Open Access Journals (Sweden)

    Kumar Vikram

    2008-01-01

    Full Text Available AbstractCarbon nanotube (CNT films were grown by microwave plasma-enhanced chemical vapor deposition process on four types of Si substrates: (i mirror polished, (ii catalyst patterned, (iii mechanically polished having pits of varying size and shape, and (iv electrochemically etched. Iron thin film was used as catalytic material and acetylene and ammonia as the precursors. Morphological and structural characteristics of the films were investigated by scanning and transmission electron microscopes, respectively. CNT films of different morphology such as vertically aligned, randomly oriented flowers, or honey-comb like, depending on the morphology of the Si substrates, were obtained. CNTs had sharp tip and bamboo-like internal structure irrespective of growth morphology of the films. Comparative field emission measurements showed that patterned CNT films and that with randomly oriented morphology had superior emission characteristics with threshold field as low as ~2.0 V/μm. The defective (bamboo-structure structures of CNTs have been suggested for the enhanced emission performance of randomly oriented nanotube samples.

  14. Effect of substrate on the growth, nutritional and bioactive ...

    African Journals Online (AJOL)

    rosemary

    2016-07-06

    Jul 6, 2016 ... growth, determining nutritional and bioactive components of two oyster mushroom, Pleurotus ostreatus and. Pleurotus ... and the method of cultivation are of major importance ..... rendered alkaline with a few drops of ammonia solution. 5 ..... production and non-enzymatic antioxidant activity of Pleurotus.

  15. Substrate dependent hierarchical structures of RF sputtered ZnS films

    Science.gov (United States)

    Chalana, S. R.; Mahadevan Pillai, V. P.

    2018-05-01

    RF magnetron sputtering technique was employed to fabricate ZnS nanostructures with special emphasis given to study the effect of substrates (quartz, glass and quartz substrate pre-coated with Au, Ag, Cu and Pt) on the structure, surface evolution and optical properties. Type of substrate has a significant influence on the crystalline phase, film morphology, thickness and surface roughness. The present study elucidates the suitability of quartz substrate for the deposition of stable and highly crystalline ZnS films. We found that the role of metal layer on quartz substrate is substantial in the preparation of hierarchical ZnS structures and these structures are of great importance due to its high specific area and potential applications in various fields. A mechanism for morphological evolution of ZnS structures is also presented based on the roughness of substrates and primary nonlocal effects in sputtering. Furthermore, the findings suggest that a controlled growth of hierarchical ZnS structures may be achieved with an ordinary RF sputtering technique by changing the substrate type.

  16. The Aspergillus niger growth on the treated concrete substrate using variable antifungals

    Science.gov (United States)

    Parjo, U. K.; Sunar, N. M.; Leman, A. M.; Gani, P.; Embong, Z.; Tajudin, S. A. A.

    2016-11-01

    The aim of this study was to evaluate the Aspergillus niger (A. niger) growth on substrates after incorporates with different compounds of antifungals which is normally used in food industry. The antifungals named as potassium sorbate (PS), calcium benzoate (CB) and zinc salicylate (ZS) were applied on concrete substrate covered with different wall finishing such as acrylic paint (AP), glycerol based paint (GBP), thin wallpaper (THIN) and thick wallpaper (THICK). The concrete substrate were inoculated with spore suspension, incubated at selected temperature (30oC) and relative humidity (90%)in plant growth chamber. The observations were done from the Day 3 until Day 27. The results showed that the growth of the A. niger for concrete treated by PS for AP, GBP, THIN, and THICK were 64%, 32%, 11% and 100%, respectively. Meanwhile for CB, the growth of A. niger on AP, GBP, THIN, and THICK were 100%, 12%, 41%, and 13%, respectively. Similarly, treated concrete by ZS revealed that the growth of A. niger on the same substrate cover were 33%, 47%, 40%, and 39%, respectively. The results obtained in this study provide a valuable knowledge on the abilities of antifungals to remediate A. niger that inoculated on the concrete substrate. Consequently, this study proved that the PS covering with THIN more efficiency compares CB and ZS to prevent A. niger growth.

  17. Growth and yield of Dutch cucumber grown in a protected environment and with alternative organic substrates

    Directory of Open Access Journals (Sweden)

    Cinthya Meneses Fernández

    2018-05-01

    Full Text Available The replacement of imported substrates by local materials is a trend in severaltechnifiedproduction systems, given the cost reduction and the importance of agricultural by-products, formerly considered to be waste. The main objective of this work was to validate the effect of different substrates on the growth and productivity of Dutch cucumber plants under greenhouse conditions. The study took place from October 2012 to January 2013, at the Agricultural Experiment Station Fabio Baudrit, Alajuela, Costa Rica. Variety Fuerte was used and four mixed substrates (volume ratio made of local raw materials as coconut fiber (FC, oil palm leaf fiber (FP, organic compost (ABO, and sawdust (AS as well as a commercial treatment (control constituted by coco coir slabs were analyzed. Substrate water content, plant growth (vegetative phase, and yield were evaluated according to commercial size (S, M, L, XL, and rejected. The growth of Dutch cucumber plants, variety Fuerte, was higher on substrates with coconut fiber 40% + oil palm leaf fiber 40% + organic compost 20%, and coconut fiber 70% + organic compost 30%, while yield of the same two substrates was 15.57 and 15.44 kg/m2, respectively. Both treatments were statistically equal to the commercial coco coir substrate slabs with a yield of 14.77 kg/m2. Result attributed to the nutritional contribution of the organic compost (high K, Ca, and Mg along with and to the effects of aeration and water retention of fibers.

  18. Unbounded autocatalytic growth on diffusive substrate: The extinction transition

    International Nuclear Information System (INIS)

    Moalem, Sasi; Shnerb, Nadav M.

    2007-01-01

    The effect of diffusively correlated spatial fluctuations on the proliferation-extinction transition of autocatalytic agents is investigated numerically. Reactants adaptation to spatio-temporal active regions is shown to lead to proliferation even if the mean field rate equations predict extinction, in agreement with previous theoretical predictions. While in the proliferation phase the system admits a typical time scale that dictates the exponential growth, the extinction times distribution obeys a power law at the parameter region considered

  19. Epitaxial growth on porous GaAs substrates

    Czech Academy of Sciences Publication Activity Database

    Grym, Jan; Nohavica, Dušan; Gladkov, Petar; Hulicius, Eduard; Pangrác, Jiří; Piksová, K.

    2013-01-01

    Roč. 16, č. 1 (2013), s. 59-64 ISSN 1631-0748 R&D Projects: GA ČR GAP102/10/1201; GA ČR GAP108/10/0253 Institutional support: RVO:67985882 ; RVO:68378271 Keywords : Electrochemical etching * Porous semiconductors * Epitaxial growth * GaAs Subject RIV: BH - Optics, Masers, Lasers; JA - Electronics ; Optoelectronics, Electrical Engineering (FZU-D) Impact factor: 1.483, year: 2013

  20. Influence of the Hydrothermal Method Growth Parameters on the Zinc Oxide Nanowires Deposited on Several Substrates

    Directory of Open Access Journals (Sweden)

    Concepción Mejía-García

    2014-01-01

    Full Text Available We report the synthesis of ZnO nanowires grown on several substrates (PET, glass, and Si using a two-step process: (a preparation of the seed layer on the substrate by spin coating, from solutions of zinc acetate dihydrate and 1-propanol, and (b growth of the ZnO nanostructures by dipping the substrate in an equimolar solution of zinc nitrate hexahydrate and hexamethylenetetramine. Subsequently, films were thermally treated with a commercial microwave oven (350 and 700 W for 5, 20, and 35 min. The ZnO nanowires obtained were characterized structurally, morphologically, and optically using XRD, SEM, and UV-VIS transmission, respectively. XRD patterns spectra revealed the presence of Zn(OH2 on the films grown on glass and Si substrates. A preferential orientation along c-axis directions for films grown on PET substrate was observed. An analysis by SEM revealed that the growth of the ZnO nanowires on PET and glass is better than the growth on Si when the same growth parameters are used. On glass substrates, ZnO nanowires less than 50 nm in diameter and between 200 nm and 1200 nm in length were obtained. The ZnO nanowires band gap energy for the films grown on PET and glass was obtained from optical transmission spectra.

  1. Substrates and oxygen dependent citric acid production by Yarrowia lipolytica: insights through transcriptome and fluxome analyses.

    Science.gov (United States)

    Sabra, Wael; Bommareddy, Rajesh Reddy; Maheshwari, Garima; Papanikolaou, Seraphim; Zeng, An-Ping

    2017-05-08

    Unlike the well-studied backer yeast where catabolite repression represents a burden for mixed substrate fermentation, Yarrowia lipolytica, an oleaginous yeast, is recognized for its potential to produce single cell oils and citric acid from different feedstocks. These versatilities of Y. lipolytica with regards to substrate utilization make it an attractive host for biorefinery application. However, to develop a commercial process for the production of citric acid by Y. lipolytica, it is necessary to better understand the primary metabolism and its regulation, especially for growth on mixed substrate. Controlling the dissolved oxygen concentration (pO 2 ) in Y. lipolytica cultures enhanced citric acid production significantly in cultures grown on glucose in mono- or dual substrate fermentations, whereas with glycerol as mono-substrate no significant effect of pO 2 was found on citrate production. Growth on mixed substrate with glucose and glycerol revealed a relative preference of glycerol utilization by Y. lipolytica. Under optimized conditions with pO 2 control, the citric acid titer on glucose in mono- or in dual substrate cultures was 55 and 50 g/L (with productivity of 0.6 g/L*h in both cultures), respectively, compared to a maximum of 18 g/L (0.2 g/L*h) with glycerol in monosubstrate culture. Additionally, in dual substrate fermentation, glycerol limitation was found to trigger citrate consumption despite the presence of enough glucose in pO 2 -limited culture. The metabolic behavior of this yeast on different substrates was investigated at transcriptomic and 13 C-based fluxomics levels. Upregulation of most of the genes of the pentose phosphate pathway was found in cultures with highest citrate production with glucose in mono- or in dual substrate fermentation with pO 2 control. The activation of the glyoxylate cycle in the oxygen limited cultures and the imbalance caused by glycerol limitation might be the reason for the re-consumption of citrate in

  2. Substrate-dependent denitrification of abundant probe-defined denitrifying bacteria in activated sludge.

    Science.gov (United States)

    Morgan-Sagastume, Fernando; Nielsen, Jeppe Lund; Nielsen, Per Halkjaer

    2008-11-01

    The denitrification capacity of different phylogenetic bacterial groups was investigated on addition of different substrates in activated sludge from two nutrient-removal plants. Nitrate/nitrite consumption rates (CRs) were calculated from nitrate and nitrite biosensor, in situ measurements. The nitrate/nitrite CRs depended on the substrate added, and acetate alone or combined with other substrates yielded the highest rates (3-6 mg N gVSS(-1) h(-1)). The nitrate CRs were similar to the nitrite CRs for most substrates tested. The structure of the active denitrifying population was investigated using heterotrophic CO2 microautoradiography (HetCO2-MAR) and FISH. Probe-defined denitrifiers appeared as specialized substrate utilizers despite acetate being preferentially used by most of them. Azoarcus and Accumulibacter abundance in the two different sludges was related to differences in their substrate-specific nitrate/nitrite CRs. Aquaspirillum-related bacteria were the most abundant potential denitrifiers (c. 20% of biovolume); however, Accumulibacter (3-7%) and Azoarcus (2-13%) may have primarily driven denitrification by utilizing pyruvate, ethanol, and acetate. Activated sludge denitrification was potentially conducted by a diverse, versatile population including not only Betaproteobacteria (Aquaspirillum, Thauera, Accumulibacter, and Azoarcus) but also some Alphaproteobacteria and Gammaproteobacteria, as indicated by the assimilation of 14CO2 by these probe-defined groups with a complex substrate mixture as an electron donor and nitrite as an electron acceptor in HetCO2-MAR-FISH tests.

  3. Three-dimensionally structured silicon as a substrate for the MOVPE growth of GaN nanoLEDs

    Energy Technology Data Exchange (ETDEWEB)

    Fuendling, Soenke; Li, Shunfeng; Soekmen, Uensal; Merzsch, Stephan; Peiner, Erwin; Wehmann, Hergo-Heinrich; Waag, Andreas [Institut fuer Halbleitertechnik, TU Braunschweig, Braunschweig (Germany); Hinze, Peter; Weimann, Thomas [Physikalisch-Technische Bundesanstalt (PTB), Braunschweig (Germany); Jahn, Uwe; Trampert, Achim; Riechert, Henning [Paul-Drude-Institut fuer Festkoerperelektronik, Berlin (Germany)

    2009-06-15

    Three-dimensionally patterned Si(111) substrates are used to grow GaN based heterostructures by metalorganic vapour phase epitaxy, with the goal of fabricating well controlled, defect reduced GaN-based nanoLEDs. In contrast to other approaches to achieve GaN nanorods, we employed silicon substrates with deep etched nanopillars to control the GaN nanorods growth by varying the size and distance of the Si pillars. The small footprint of GaN nanorods grown on Si pillars minimise the influence of the lattice mismatched substrate and improve the material quality. For the Si pillars an inductively coupled plasma dry-etching process at cryogenic temperature has been developed. An InGaN/GaN multi quantum well (MQW) structure has been incorporated into the GaN nanorods. We found GaN nanostructures grown on top of the silicon pillars with a pyramidal shape. This shape results from a competitive growth on different facets as well as from surface diffusion of the growth species. Spatially resolved optical properties of the structures are analysed by cathodoluminescence. Strongly spatial-dependent MQW emission spectra indicate the growth rate differences on top of the rods. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Substrate temperature dependence of ZnTe epilayers grown on GaAs(0 0 1) by molecular beam epitaxy

    Science.gov (United States)

    Zhao, Jie; Zeng, Yiping; Liu, Chao; Li, Yanbo

    2010-04-01

    ZnTe thin films have been grown on GaAs(0 0 1) substrates at different temperatures with constant Zn and Te beam equivalent pressures (BEPs) by molecular beam epitaxy (MBE). In situ reflection high-energy electron diffraction (RHEED) observation indicates that two-dimensional (2D) growth mode can be established after around one-minute three-dimensional (3D) nucleation by increasing the substrate temperature to 340 °C. We found that Zn desorption from the ZnTe surface is much greater than that of Te at higher temperatures, and estimated the Zn sticking coefficient by the evolution of growth rate. The Zn sticking coefficient decreases from 0.93 to 0.58 as the temperature is elevated from 320 to 400 °C. The ZnTe epilayer grown at 360 °C displays the narrowest full-width at half-maximum (FWHM) of 660 arcsec from (0 0 4) reflection in double-crystal X-ray rocking curve (DCXRC) measurements. The surface morphology of ZnTe epilayers is strongly dependent on the substrate temperature, and the root-mean-square (RMS) roughness diminishes drastically with the increase in temperature.

  5. Effects of substrate concentrations on the growth of heterotrophic bacteria and algae in secondary facultative ponds.

    Science.gov (United States)

    Kayombo, S; Mbwette, T S A; Katima, J H Y; Jorgensen, S E

    2003-07-01

    This paper presents the effect of substrate concentration on the growth of a mixed culture of algae and heterotrophic bacteria in secondary facultative ponds (SFPs) utilizing settled domestic sewage as a sole source of organic carbon. The growth of the mixed culture was studied at the concentrations ranging between 200 and 800 mg COD/l in a series of batch chemostat reactors. From the laboratory data, the specific growth rate (micro) was determined using the modified Gompertz model. The maximum specific growth rate ( micro(max)) and half saturation coefficients (K(s)) were calculated using the Monod kinetic equation. The maximum observed growth rate ( micro(max)) for heterotrophic bacteria was 3.8 day(-1) with K(s) of 200 mg COD/l. The micro(max) for algal biomass based on suspended volatile solids was 2.7 day(-1) with K(s) of 110 mg COD/l. The micro(max) of algae based on the chlorophyll-a was 3.5 day(-1) at K(s) of 50mg COD/l. The observed specific substrate removal by heterotrophic bacteria varied between the concentrations of substrate used and the average value was 0.82 (mg COD/mg biomass). The specific substrate utilization rate in the bioreactors was direct proportional to the specific growth rate. Hence, the determined Monod kinetic parameters are useful for the definition of the operation of SFPs.

  6. Aqueous chemical growth and patterning of ZnO nanopillars on different substrate materials

    Energy Technology Data Exchange (ETDEWEB)

    Kreye, M.; Postels, B.; Wehmann, H.H.; Waag, A. [Institute of Semiconductor Technology, Technical University of Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany); Fuhrmann, D.; Hangleiter, A. [Institute of Applied Physics, Technical University of Braunschweig, Mendelssohnstrasse 2, 38106 Braunschweig (Germany)

    2006-03-15

    Aqueous chemical growth (ACG) is a low-temperature approach that is only weakly influenced by the substrate and allows for the growth of ZnO nanopillars on various substrates. ACG is an efficient way to generate wafer-scale and densely packed arrays of ZnO nanopillars even on polymer materials. Photoluminescence (PL) characterisation clearly shows a comparatively strong band-edge luminescence even at room temperature that is accompanied with a rather weak visible luminescence in the yellow/orange spectral range. We introduce a rather simple postgrowth lithographic technique. Patterning of ZnO nanopillars even on layered conducting and flexible substrate materials using ACG as a low-temperature growth technique is demonstrated. The economical potential for future applications and devices using ZnO nanopillar arrays is discussed. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Profiling Y561-dependent and -independent substrates of CSF-1R in epithelial cells.

    Directory of Open Access Journals (Sweden)

    Melodie L Knowlton

    2010-10-01

    Full Text Available Receptor tyrosine kinases (RTKs activate multiple downstream cytosolic tyrosine kinases following ligand stimulation. SRC family kinases (SFKs, which are recruited to activated RTKs through SH2 domain interactions with RTK autophosphorylation sites, are targets of many subfamilies of RTKs. To date, there has not been a systematic analysis of the downstream substrates of such receptor-activated SFKs. Here, we conducted quantitative mass spectrometry utilizing stable isotope labeling (SILAC analysis to profile candidate SRC-substrates induced by the CSF-1R tyrosine kinase by comparing the phosphotyrosine-containing peptides from cells expressing either CSF-1R or a mutant form of this RTK that is unable to bind to SFKs. This analysis identified previously uncharacterized changes in tyrosine phosphorylation induced by CSF-1R in mammary epithelial cells as well as a set of candidate substrates dependent on SRC recruitment to CSF-1R. Many of these candidates may be direct SRC targets as the amino acids flanking the phosphorylation sites in these proteins are similar to known SRC kinase phosphorylation motifs. The putative SRC-dependent proteins include known SRC substrates as well as previously unrecognized SRC targets. The collection of substrates includes proteins involved in multiple cellular processes including cell-cell adhesion, endocytosis, and signal transduction. Analyses of phosphoproteomic data from breast and lung cancer patient samples identified a subset of the SRC-dependent phosphorylation sites as being strongly correlated with SRC activation, which represent candidate markers of SRC activation downstream of receptor tyrosine kinases in human tumors. In summary, our data reveal quantitative site-specific changes in tyrosine phosphorylation induced by CSF-1R activation in epithelial cells and identify many candidate SRC-dependent substrates phosphorylated downstream of an RTK.

  8. Aminoacid polymorphisms of insulin receptor substrate-1 in non-insulin-dependent diabetes mellitus

    DEFF Research Database (Denmark)

    Almind, K; Bjørbaek, C; Vestergaard, H

    1993-01-01

    Since relative or absolute insulin deficiency and insulin insensitivity are involved in the aetiology of non-insulin-dependent diabetes mellitus (NIDDM), we examined whether patients with NIDDM exhibit genetic variability in the coding region of insulin receptor substrate-1 (IRS-1), a candidate...

  9. Growth and sporulation of Trichoderma polysporum on organic substrates by addition of carbon and nitrogen sources

    International Nuclear Information System (INIS)

    Rajput, A.Q.; Shahzad, S.

    2015-01-01

    During the present study nine different organic substrates viz., rice grains, sorghum grains, wheat grains, millet grains, wheat straw, rice husk, cow dung, sawdust and poultry manure were used for mass multiplication of Trichoderma polysporum. Grains, especially sorghum grains were found to be the best substrate for T. polysporum. Wheat straw and rice husk were less suitable, whereas, cow dung, sawdust and poultry manure were not suitable for growth of the fungus. Sucrose at the rate of 30,000 ppm and ammonium nitrate at the rate of 3,000 ppm were found to be the best carbon and nitrogen sources for growth and sporulation of T. polysporum. Amendment of the selected C and N sources to wheat straw, rice husk and millet grains resulted in significantly higher growth and conidia production by T. polysporum as compared to un-amended substrates. Sorghum and rice grains showed suppression in growth and sporulation of T. polysporum when amended with C and N sources. During studies on shelf life, populations of T. polysporum attained the peck at 60-135 days intervals on different substrates and declined gradually thereafter. However, even after 330 days, the populations were greater than the population at 0-day. At 345-360 days interval, populations were less than the initial populations at 0- days. Shelf life on C+N amended wheat straw and rice husk were more as compared to un-amended substrates. (author)

  10. Mammalian cell growth on gold nanoparticle-decorated substrates is influenced by the nanoparticle coating

    Directory of Open Access Journals (Sweden)

    Christina Rosman

    2014-12-01

    Full Text Available In this work, we study epithelial cell growth on substrates decorated with gold nanorods that are functionalized either with a positively charged cytotoxic surfactant or with a biocompatible polymer exhibiting one of two different end groups, resulting in a neutral or negative surface charge of the particle. Upon observation of cell growth for three days by live cell imaging using optical dark field microscopy, it was found that all particles supported cell adhesion while no directed cell migration and no significant particle internalization occurred. Concerning cell adhesion and spreading as compared to cell growth on bare substrates after 3 days of incubation, a reduction by 45% and 95%, respectively, for the surfactant particle coating was observed, whereas the amino-terminated polymer induced a reduction by 30% and 40%, respectively, which is absent for the carboxy-terminated polymer. Furthermore, interface-sensitive impedance spectroscopy (electric cell–substrate impedance sensing, ECIS was employed in order to investigate the micromotility of cells added to substrates decorated with various amounts of surfactant-coated particles. A surface density of 65 particles/µm2 (which corresponds to 0.5% of surface coverage with nanoparticles diminishes micromotion by 25% as compared to bare substrates after 35 hours of incubation. We conclude that the surface coating of the gold nanorods, which were applied to the basolateral side of the cells, has a recognizable influence on the growth behavior and thus the coating should be carefully selected for biomedical applications of nanoparticles.

  11. Growth and properties of blue/green InGaN/GaN MQWs on Si(111) substrates

    International Nuclear Information System (INIS)

    Lee, Kang Jea; Oh, Tae Su; Kim, Tae Ki; Yang, Gye Mo; Lim, Kee Young

    2005-01-01

    InGaN/GaN multiple quantum wells (MQWs) were grown on highly tensile-strained GaN films on Si(111) substrate by metalorganic chemical vapor deposition. Due to the large difference of lattice constant and thermal expansion coefficient between GaN and Si, GaN growth on Si(111) substrate usually leads to an initially high dislocation density and cracks. We demonstrate low dislocation-density and crack-free GaN films grown on Si(111) substrate by introducing an AlN/GaN strain-compensation layer and Si x N y dislocation masking layer. Blue/green-emitting InGaN/GaN MQW heterostructures have been successfully grown on Si(111) substrates. Two sets of InGaN/GaN MQWs with different In solid composition and number of pairs grown between 820 .deg. C and 900 .deg. C were studied by high-resolution X-ray diffraction and photoluminescence spectroscopy. The emission wavelengths of InGaN MQW structures were significantly dependent on growth temperature.

  12. Growth on elastic silicone substrate elicits a partial myogenic response in periodontal ligament derived stem cells

    Directory of Open Access Journals (Sweden)

    Daniel Pelaez

    2016-12-01

    Full Text Available The processes of cellular differentiation and phenotypic maintenance can be influenced by stimuli from a variety of different factors. One commonly overlooked factor is the mechanical properties of the growth substrate in which stem cells are maintained or differentiated down various lineages. Here we explored the effect that growth on an elastic silicone substrate had on the myogenic expression and cytoskeletal morphology of periodontal ligament derived stem cells. Cells were grown on either collagen I coated tissue culture polystyrene plates or collagen I coated elastic silicone membranes for a period of 4 days without further induction from soluble factors in the culture media. Following the 4-day growth, gene expression and immunohistochemical analysis for key cardiomyogenic markers was performed along with a morphological assessment of cytoskeletal organization. Results show that cells grown on the elastic substrate significantly upregulate key markers associated with contractile activity in muscle tissues. Namely, the myosin light chain polypeptides 2 and 7, as well as the myosin heavy chain polypeptide 7 genes underwent a statistically significant upregulation in the cells grown on elastic silicone membranes. Similarly, the cells on the softer elastic substrate stained positive for both sarcomeric actin and cardiac troponin t proteins following just 4 days of growth on the softer material. Cytoskeletal analysis showed that substrate stiffness had a marked effect on the organization and distribution of filamentous actin fibers within the cell body. Growth on silicone membranes produced flatter and shorter cellular morphologies with filamentous actin fibers projecting anisotropically throughout the cell body. These results demonstrate how crucial the mechanical properties of the growth substrate of cells can be on the ultimate cellular phenotype. These observations highlight the need to further optimize differentiation protocols to enhance

  13. Growth of Gold-assisted Gallium Arsenide Nanowires on Silicon Substrates via Molecular Beam Epitaxy

    Directory of Open Access Journals (Sweden)

    Ramon M. delos Santos

    2008-06-01

    Full Text Available Gallium arsenide nanowires were grown on silicon (100 substrates by what is called the vapor-liquid-solid (VLS growth mechanism using a molecular beam epitaxy (MBE system. Good quality nanowires with surface density of approximately 108 nanowires per square centimeter were produced by utilizing gold nanoparticles, with density of 1011 nanoparticles per square centimeter, as catalysts for nanowire growth. X-ray diffraction measurements, scanning electron microscopy, transmission electron microscopy and Raman spectroscopy revealed that the nanowires are epitaxially grown on the silicon substrates, are oriented along the [111] direction and have cubic zincblende structure.

  14. Evaluation of pyritic mine tailings as a plant growth substrate.

    Science.gov (United States)

    Roseby, Stuart J; Kopittke, Peter M; Mulligan, David R; Menzies, Neal W

    2017-10-01

    At the Kidston gold mine, Australia, the direct establishment of vegetation on tailings was considered as an alternative to the use of a waste rock cover. The tailings acid/base account was used to predict plant growth limitation by acidity, and thus methods capable of identifying tailings that would acidify to pH 4.5 or lower were sought. Total S was found to be poorly correlated with acid-generating sulfide, and total C was poorly correlated with acid-neutralizing carbonate, precluding the use of readily determined total S and C as predictors of net acid generation. Therefore, the selected approach used assessment of sulfide content as a predictor of acid generation, and carbonate content as a measure of the acid-neutralizing capacity available at pH 5 and above. Using this approach, the majority of tailings (67%) were found to be non-acid generating. However, areas of potentially acid-generating tailings were randomly distributed across the dam, and could only be located by intensive sampling. The limitations imposed by the large sample numbers, and costly analysis of sulfide and carbonate, make it impractical to identify and ameliorate acid-generating areas prior to vegetation establishment. However, as only a small proportion of the tailings will acidify, a strategy of re-treating acid areas following oxidation is suggested. The findings of the present study will assist in the selection of appropriate methods for the prediction of net acid generation, particularly where more conservative measurements are required to allow vegetation to be established directly in tailings. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Critical Determinants of Substrate Recognition by Cyclin-Dependent Kinase-like 5 (CDKL5).

    Science.gov (United States)

    Katayama, Syouichi; Sueyoshi, Noriyuki; Kameshita, Isamu

    2015-05-19

    Cyclin-dependent kinase-like 5 (CDKL5) is a Ser/Thr protein kinase known to be associated with X-linked neurodevelopmental disorders. In a previous study, we identified amphiphysin 1 (Amph1) as a potential substrate for CDKL5 and identified a single phosphorylation site at Ser-293. In this study, we investigated the molecular mechanisms of substrate recognition by CDKL5 using Amph1 as a model substrate. Amph1 served as an efficient CDKL5 substrate, whereas Amph2, a structurally related homologue of Amph1, was not phosphorylated by CDKL5. The sequence around the Amph1 phosphorylation site is RPR(293)SPSQ, while the corresponding sequence in Amph2 is IPK(332)SPSQ. To define the amino acid sequence specificity of the substrate, various point mutants of Amph1 and Amph2 were prepared and phosphorylated by CDKL5. Both Amph2(I329R) and Amph1 served as efficient CDKL5 substrates, but Amph1(R290I) did not, indicating that the arginyl residue at the P -3 position is critical for substrate recognition. With regard to prolyl residues around the phosphorylation site of Amph1, Pro-291 at the P -2 position, but not Pro-294 at the P +1 position, is indispensable for phosphorylation by CDKL5. Phosphorylation experiments using various deletion mutants of Amph1 revealed that the proline-rich domain (PRD) (amino acids 247-315) alone was not phosphorylated by CDKL5. In contrast, Amph1(247-385), which comprised the PRD and CLAP domains, served as an efficient CDKL5 substrate. These results, taken together, suggest that both the phosphorylation site sequence (RPXSX) and the CLAP domain structure in Amph1 play crucial roles in recognition and phosphorylation by CDKL5.

  16. GDH-Dependent Glutamate Oxidation in the Brain Dictates Peripheral Energy Substrate Distribution

    DEFF Research Database (Denmark)

    Karaca, Melis; Frigerio, Francesca; Migrenne, Stephanie

    2015-01-01

    in a central energy-deprivation state with increased ADP/ATP ratios and phospho-AMPK in the hypothalamus. This induced changes in the autonomous nervous system balance, with increased sympathetic activity promoting hepatic glucose production and mobilization of substrates reshaping peripheral energy stores...... glutamate dehydrogenase (GDH) activity. Here, we investigated the significance of glutamate as energy substrate for the brain. Upon glutamate exposure, astrocytes generated ATP in a GDH-dependent way. The observed lack of glutamate oxidation in brain-specific GDH null CnsGlud1(-/-) mice resulted...

  17. Modeling of metal nanocluster growth on patterned substrates and surface pattern formation under ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Numazawa, Satoshi

    2012-11-01

    are considered as local transition events constrained in potential energy wells over certain local time periods. These processes are represented by Markov chains of multi-dimensional Boolean valued functions in three dimensional lattice space. Consequently, the fluctuating system evolution process is implemented as a Markov chain of equivalence class objects. It is shown that the process can be characterized by the acceptance of metastable local transitions. The method is applied to a problem of Au and Ag cluster growth on a rippled surface. The simulation predicts the existence of a morphology dependent transition time limit from a local metastable to stable state for subsequent cluster growth by accretion. The third topic is the formation of ripple structures on ion bombarded semiconductor surfaces treated in the first topic as the prepatterned substrate of the metallic deposition. This intriguing phenomenon has been known since the 1960's and various theoretical approaches have been explored. These previous models are discussed and a new non-linear model is formulated, based on the local atomic flow and associated density change in the near surface region. Within this framework ripple structures are shown to form without the necessity to invoke surface diffusion or large sputtering as important mechanisms. The model can also be extended to the case where sputtering is important and it is shown that in this case, certain 'magic' angles can occur at which the ripple patterns are most clearly defined. The results including some analytic solutions of the nonlinear equation of motions are in very good agreement with experimental observation.

  18. Modeling of metal nanocluster growth on patterned substrates and surface pattern formation under ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Numazawa, Satoshi

    2012-11-01

    are considered as local transition events constrained in potential energy wells over certain local time periods. These processes are represented by Markov chains of multi-dimensional Boolean valued functions in three dimensional lattice space. Consequently, the fluctuating system evolution process is implemented as a Markov chain of equivalence class objects. It is shown that the process can be characterized by the acceptance of metastable local transitions. The method is applied to a problem of Au and Ag cluster growth on a rippled surface. The simulation predicts the existence of a morphology dependent transition time limit from a local metastable to stable state for subsequent cluster growth by accretion. The third topic is the formation of ripple structures on ion bombarded semiconductor surfaces treated in the first topic as the prepatterned substrate of the metallic deposition. This intriguing phenomenon has been known since the 1960's and various theoretical approaches have been explored. These previous models are discussed and a new non-linear model is formulated, based on the local atomic flow and associated density change in the near surface region. Within this framework ripple structures are shown to form without the necessity to invoke surface diffusion or large sputtering as important mechanisms. The model can also be extended to the case where sputtering is important and it is shown that in this case, certain 'magic' angles can occur at which the ripple patterns are most clearly defined. The results including some analytic solutions of the nonlinear equation of motions are in very good agreement with experimental observation.

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

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Young Jun; Jang, Hanmin; Lee, Kwan-Soo [School of Mechanical Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Kim, Dong Rip, E-mail: dongrip@hanyang.ac.kr [School of Mechanical Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Institute of Nano Science and Technology, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2015-06-15

    Graphical abstract: - Highlights: • Cerium oxide nanorods were uniformly grown on diverse substrates. • Changes in growth conditions led to morphology evolution of cerium oxide nanostructures. • The grown cerium oxide nanostructures were single or poly crystalline. • Direct growth of cerium oxide nanorods made the diverse substrates superhydrophobic and anti-corrosive without any surface modifiers. - Abstract: 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.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    Graphical abstract: - Highlights: • Cerium oxide nanorods were uniformly grown on diverse substrates. • Changes in growth conditions led to morphology evolution of cerium oxide nanostructures. • The grown cerium oxide nanostructures were single or poly crystalline. • Direct growth of cerium oxide nanorods made the diverse substrates superhydrophobic and anti-corrosive without any surface modifiers. - Abstract: 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

  1. Molecular-mediated crystal growth of PbTiO3 nanostructure on silicon substrate

    International Nuclear Information System (INIS)

    Chao Chunying; Ren Zhaohui; Liu Zhenya; Xiao Zhen; Xu Gang; Li Xiang; Wei Xiao; Shen Ge; Han Gaorong

    2011-01-01

    A simple approach based on an organically modified sol-gel process has been developed to fabricate PbTiO 3 (PT) nanocrystals on Si (1 0 0) substrate, where the amorphous powder modified by acetylacetone (acac) was used as precursor. After dropping the amorphous powder precursor prepared by freeze-drying process, PT nanocrystals on Si (1 0 0) substrate were obtained after heat treatment at 720 deg. C for 30 min in air. PT nanocrystals have been detected by XRD to be tetragonal perovskite structure. With the increase of acac/Pb molar ratio, the relative (1 0 0)/(0 0 1) diffraction peak intensity gradually increases, which probably suggested an oriented growth of PT nanocrystal along [1 0 0] on Si (1 0 0) substrates. In addition, Atomic force microscopy (AFM) results indicated that the height and the average lateral size of PT nanocrystal increased and then decreased as the acac/Pb molar ratio increased. Piezoelectric force microscopy (PFM) results demonstrated that all the samples show obvious piezoelectric activity. These results implied that the acetylacetone molecular mediated the growth of PT nanocrystals on Si (1 0 0) substrates possibly by the acac/Pb molar ratio. This simple method has been suggested to be attractive for tailoring an oriented growth of the nanostructures of perovskite oxide systems on Si substrates.

  2. Investment in secreted enzymes during nutrient-limited growth is utility dependent.

    Science.gov (United States)

    Cezairliyan, Brent; Ausubel, Frederick M

    2017-09-12

    Pathogenic bacteria secrete toxins and degradative enzymes that facilitate their growth by liberating nutrients from the environment. To understand bacterial growth under nutrient-limited conditions, we studied resource allocation between cellular and secreted components by the pathogenic bacterium Pseudomonas aeruginosa during growth on a protein substrate that requires extracellular digestion by secreted proteases. We identified a quantitative relationship between the rate of increase of cellular biomass under nutrient-limiting growth conditions and the rate of increase in investment in secreted proteases. Production of secreted proteases is stimulated by secreted signals that convey information about the utility of secreted proteins during nutrient-limited growth. Growth modeling using this relationship recapitulated the observed kinetics of bacterial growth on a protein substrate. The proposed regulatory strategy suggests a rationale for quorum-sensing-dependent stimulation of the production of secreted enzymes whereby investment in secreted enzymes occurs in proportion to the utility they confer. Our model provides a framework that can be applied toward understanding bacterial growth in many environments where growth rate is limited by the availability of nutrients.

  3. Temperature dependent magnetic properties of the GaAs substrate of spin-LEDs

    International Nuclear Information System (INIS)

    Ney, A; Harris, J S Jr; Parkin, S S P

    2006-01-01

    The temperature dependence of the magnetization of a light emitting diode having a ferromagnetic contact (spin-LED) is measured from 2 to 300 K in magnetic fields from 30 to 70 kOe and it is found that it originates from the GaAs substrate. The magnetization of GaAs comprises a van Vleck-type paramagnetic contribution to the susceptibility which scales inversely with the band gap of the semiconductor. Thus, the temperature dependence of the band gap of GaAs accounts for the non-linear temperature dependent magnetic susceptibility of GaAs and thus, at large magnetic fields, for the spin-LED

  4. Patterned growth of carbon nanotubes on Si substrates without predeposition of metal catalysts

    Science.gov (United States)

    Chen, Y.; Yu, J.

    2005-07-01

    Aligned carbon nanotubes (CNTs) can be readily synthesized on quartz or silicon-oxide-coated Si substrates using a chemical vapor deposition method, but it is difficult to grow them on pure Si substrates without predeposition of metal catalysts. We report that aligned CNTs were grown by pyrolysis of iron phthalocyanine at 1000°C on the templates created on Si substrates with simple mechanical scratching. Scanning electron microscopy and x-ray energy spectroscopy analysis revealed that the trenches and patterns created on the surface of Si substrates were preferred nucleation sites for nanotube growth due to a high surface energy, metastable surface structure, and possible capillarity effect. A two-step pyrolysis process maintained Fe as an active catalyst.

  5. Growth of bi- and tri-layered graphene on silicon carbide substrate via molecular dynamics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Min, Tjun Kit; Yoon, Tiem Leong [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Lim, Thong Leng [Faculty of Engineering and Technology, Multimedia University, Melaka Campus, 75450 Melaka (Malaysia)

    2015-04-24

    Molecular dynamics (MD) simulation with simulated annealing method is used to study the growth process of bi- and tri-layered graphene on a 6H-SiC (0001) substrate via molecular dynamics simulation. Tersoff-Albe-Erhart (TEA) potential is used to describe the inter-atomic interactions among the atoms in the system. The formation temperature, averaged carbon-carbon bond length, pair correlation function, binding energy and the distance between the graphene formed and the SiC substrate are quantified. The growth mechanism, graphitization of graphene on the SiC substrate and characteristics of the surface morphology of the graphene sheet obtained in our MD simulation compare well to that observed in epitaxially grown graphene experiments and other simulation works.

  6. Rapid growth of single-layer graphene on the insulating substrates by thermal CVD

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C.Y. [Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Dai, D.; Chen, G.X.; Yu, J.H. [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Nishimura, K. [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Advanced Nano-processing Engineering Lab, Mechanical Systems Engineering, Kogakuin University (Japan); Lin, C.-T. [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Jiang, N., E-mail: jiangnan@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Zhan, Z.L., E-mail: zl_zhan@sohu.com [Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093 (China)

    2015-08-15

    Highlights: • A rapid thermal CVD process has been developed to directly grow graphene on the insulating substrates. • The treating time consumed is ≈25% compared to conventional CVD procedure. • Single-layer and few-layer graphene can be formed on quartz and SiO{sub 2}/Si substrates, respectively. • The formation of thinner graphene at the interface is due to the fast precipitation rate of carbon atoms during cooling. - Abstract: The advance of CVD technique to directly grow graphene on the insulating substrates is particularly significant for further device fabrication. As graphene is catalytically grown on metal foils, the degradation of the sample properties is unavoidable during transfer of graphene on the dielectric layer. Moreover, shortening the treatment time as possible, while achieving single-layer growth of graphene, is worthy to be investigated for promoting the efficiency of mass production. Here we performed a rapid heating/cooling process to grow graphene films directly on the insulating substrates by thermal CVD. The treating time consumed is ≈25% compared to conventional CVD procedure. In addition, we found that high-quality, single-layer graphene can be formed on quartz, but on SiO{sub 2}/Si substrate only few-layer graphene can be obtained. The pronounced substrate effect is attributed to the different dewetting behavior of Ni films on the both substrates at 950 °C.

  7. Effect of Different Substrates and Casing Materials on the Growth and Yield of Calocybe indica.

    Science.gov (United States)

    Amin, Ruhul; Khair, Abul; Alam, Nuhu; Lee, Tae Soo

    2010-06-01

    Calocybe indica, a tropical edible mushroom, is popular because it has good nutritive value and it can be cultivated commercially. The current investigation was undertaken to determine a suitable substrate and the appropriate thickness of casing materials for the cultivation of C. indica. Optimum mycelial growth was observed in coconut coir substrate. Primordia initiation with the different substrates and casing materials was observed between the 13th and 19th day. The maximum length of stalk was recorded from sugarcane leaf, while diameter of stalk and pileus, and thickness of pileus were found in rice straw substrate. The highest biological and economic yield, and biological efficiency were also obtained in the rice straw substrate. Cow dung and loamy soil, farm-yard manure, loamy soil and sand, and spent oyster mushroom substrates were used as casing materials to evaluate the yield and yield-contributing characteristics of C. indica. The results indicate that the number of effective fruiting bodies, the biological and economic yield, and the biological efficiency were statistically similar all of the casing materials used. The maximum biological efficiency was found in the cow dung and loamy soil casing material. The cow dung and loamy soil (3 cm thick) was the best casing material and the rice straw was the best substrate for the commercial cultivation of C. indica.

  8. Transfer free graphene growth on SiO2 substrate at 250 °C

    Science.gov (United States)

    Vishwakarma, Riteshkumar; Rosmi, Mohamad Saufi; Takahashi, Kazunari; Wakamatsu, Yuji; Yaakob, Yazid; Araby, Mona Ibrahim; Kalita, Golap; Kitazawa, Masashi; Tanemura, Masaki

    2017-03-01

    Low-temperature growth, as well as the transfer free growth on substrates, is the major concern of graphene research for its practical applications. Here we propose a simple method to achieve the transfer free graphene growth on SiO2 covered Si (SiO2/Si) substrate at 250 °C based on a solid-liquid-solid reaction. The key to this approach is the catalyst metal, which is not popular for graphene growth by chemical vapor deposition. A catalyst metal film of 500 nm thick was deposited onto an amorphous C (50 nm thick) coated SiO2/Si substrate. The sample was then annealed at 250 °C under vacuum condition. Raman spectra measured after the removal of the catalyst by chemical etching showed intense G and 2D peaks together with a small D and intense SiO2 related peaks, confirming the transfer free growth of multilayer graphene on SiO2/Si. The domain size of the graphene confirmed by optical microscope and atomic force microscope was about 5 μm in an average. Thus, this approach will open up a new route for transfer free graphene growth at low temperatures.

  9. Growth on nonpolar and semipolar GaN: The substrate dilemma

    Energy Technology Data Exchange (ETDEWEB)

    Wernicke, T.; Weyers, M. [Ferdinand-Braun-Institute, Berlin (Germany); Kneissl, M. [Ferdinand-Braun-Institute, Berlin (Germany); Institute of Solid State Physics, TU Berlin (Germany)

    2009-07-01

    Growth of nonpolar and semipolar GaN is very promising for achieving green laser diodes (LDs). However, the choice of the substrate is a difficult one: Heteroepitaxial growth on sapphire, SiC, LiAlO{sub 2} yields GaN films with a poor surface quality and high defect densities. On the other hand non- and semipolar bulk GaN substrates provide excellent crystal quality, but are so far only available in very small sizes. In this paper hetero- and homoepitaxial growth is compared. For all heteroepitaxially grown semi- and nonpolar GaN layers threading dislocations (TD) and basal plane stacking faults (BSF) can be found. There are four possible mechanisms for the generation of BSF: Growth of the N-polar basal plane, formation during nucleation at substrate steps, formation at the coalescence front of differently stacked nucleation islands, and generation at planar defects occurring in m-plane GaN on LiAlO{sub 2}. BSF induce surface roughening and are associated with partial dislocations causing nonradiative recombination. Thus they affect the performance of devices. We show that BSFs and TDs can be reduced by epitaxial lateral overgrowth resulting in several micrometer wide defect free areas. However, for LEDs larger defect-free areas are required. GaN layers grown on bulk GaN substrates exhibit a high crystal quality, but show in many cases long-range surface structures with a height of {approx}1{mu}m.

  10. The relative importance of exogenous and substrate-derived nitrogen for microbial growth during leaf decomposition

    Science.gov (United States)

    B.M. Cheever; J. R. Webster; E. E. Bilger; S. A. Thomas

    2013-01-01

    Heterotrophic microbes colonizing detritus obtain nitrogen (N) for growth by assimilating N from their substrate or immobilizing exogenous inorganic N. Microbial use of these two pools has different implications for N cycling and organic matter decomposition in the face of the global increase in biologically available N. We used sugar maple leaves labeled with

  11. Plasma deposition of thin film silicon at low substrate temperature and at high growth rate

    NARCIS (Netherlands)

    Verkerk, A.D.|info:eu-repo/dai/nl/304831719

    2009-01-01

    To expand the range of applications for thin film solar cells incorporating hydrogenated amorphous silicon (a-Si:H) and hydrogenated nanocrystalline silicon (nc-Si:H), the growth rate has to be increased 0.5 or less to several nm/s and the substrate temperature should be lowered to around 100 C. In

  12. Selective-area growth and controlled substrate coupling of transition metal dichalcogenides

    Science.gov (United States)

    Bersch, Brian M.; Eichfeld, Sarah M.; Lin, Yu-Chuan; Zhang, Kehao; Bhimanapati, Ganesh R.; Piasecki, Aleksander F.; Labella, Michael, III; Robinson, Joshua A.

    2017-06-01

    Developing a means for true bottom-up, selective-area growth of two-dimensional (2D) materials on device-ready substrates will enable synthesis in regions only where they are needed. Here, we demonstrate seed-free, site-specific nucleation of transition metal dichalcogenides (TMDs) with precise control over lateral growth by utilizing an ultra-thin polymeric surface functionalization capable of precluding nucleation and growth. This polymer functional layer (PFL) is derived from conventional photoresists and lithographic processing, and is compatible with multiple growth techniques, precursors (metal organics, solid-source) and TMDs. Additionally, we demonstrate that the substrate can play a major role in TMD transport properties. With proper TMD/substrate decoupling, top-gated field-effect transistors (FETs) fabricated with selectively-grown monolayer MoS2 channels are competitive with current reported MoS2 FETs. The work presented here demonstrates that substrate surface engineering is key to realizing precisely located and geometrically-defined 2D layers via unseeded chemical vapor deposition techniques.

  13. Effects of substrate type on plant growth and nitrogen and nitrate concentration in spinach

    Science.gov (United States)

    The effects of three commercial substrates (a mixture of forest residues, composted grape husks, and white peat; black peat; and coir) on plant growth and nitrogen (N) and nitrate (NO3) concentration and content were evaluated in spinach (Spinacia oleracea L. cv. Tapir). Spinach seedlings were trans...

  14. Connection between the growth rate distribution and the size dependent crystal growth

    Science.gov (United States)

    Mitrović, M. M.; Žekić, A. A.; IIić, Z. Z.

    2002-07-01

    The results of investigations of the connection between the growth rate dispersions and the size dependent crystal growth of potassium dihydrogen phosphate (KDP), Rochelle salt (RS) and sodium chlorate (SC) are presented. A possible way out of the existing confusion in the size dependent crystal growth investigations is suggested. It is shown that the size independent growth exists if the crystals belonging to one growth rate distribution maximum are considered separately. The investigations suggest possible reason for the observed distribution maxima widths, and the high data scattering on the growth rate versus the crystal size dependence.

  15. Crystallization and growth of Ni-Si alloy thin films on inert and on silicon substrates

    Science.gov (United States)

    Grimberg, I.; Weiss, B. Z.

    1995-04-01

    The crystallization kinetics and thermal stability of NiSi2±0.2 alloy thin films coevaporated on two different substrates were studied. The substrates were: silicon single crystal [Si(100)] and thermally oxidized silicon single crystal. In situ resistance measurements, transmission electron microscopy, x-ray diffraction, Auger electron spectroscopy, and Rutherford backscattering spectroscopy were used. The postdeposition microstructure consisted of a mixture of amorphous and crystalline phases. The amorphous phase, independent of the composition, crystallizes homogeneously to NiSi2 at temperatures lower than 200 °C. The activation energy, determined in the range of 1.4-2.54 eV, depends on the type of the substrate and on the composition of the alloyed films. The activation energy for the alloys deposited on the inert substrate was found to be lower than for the alloys deposited on silicon single crystal. The lowest activation energy was obtained for nonstoichiometric NiSi2.2, the highest for NiSi2—on both substrates. The crystallization mode depends on the structure of the as-deposited films, especially the density of the existing crystalline nuclei. Substantial differences were observed in the thermal stability of the NiSi2 compound on both substrates. With the alloy films deposited on the Si substrate, only the NiSi2 phase was identified after annealing to temperatures up to 800 °C. In the films deposited on the inert substrate, NiSi and NiSi2 phases were identified when the Ni content in the alloy exceeded 33 at. %. The effects of composition and the type of substrate on the crystallization kinetics and thermal stability are discussed.

  16. Temperature-dependent respiration-growth relations in ancestral maize cultivars

    Science.gov (United States)

    Bruce N. Smith; Jillian L. Walker; Rebekka L. Stone; Angela R. Jones; Lee D. Hansen

    2001-01-01

    Shoots from 4- to 6-day old seedlings of seven ancestral or old cultivars of Zea mays L. were placed in a calorimeter. Dark metabolic heat rate (q) and CO2 production rate (RCO2) were measured at nine temperatures (5, 10, 15, 20, 25, 30, 35, 40, and 45 °C). Temperature dependencies of q and RCO2 were used to model response of both growth and substrate carbon conversion...

  17. Effect of hydrogen flow on growth of 3C-SiC heteroepitaxial layers on Si(111) substrates

    International Nuclear Information System (INIS)

    Yan, Guoguo; Zhang, Feng; Niu, Yingxi; Yang, Fei; Liu, Xingfang; Wang, Lei; Zhao, Wanshun; Sun, Guosheng; Zeng, Yiping

    2015-01-01

    Highlights: • 3C-SiC thin films of preferential orientation along with Si(111) substrates were obtained using home-made horizontal LPCVD with different H_2 flow rate ranging from15 to 30 slm. • High H_2 flow rate will inhibit the out-diffusion of silicon atoms from silicon substrates effectively. Transformation and the mechanism of void formation are discussed based on our model. • The variation of growth rate and n-type doping with increasing H_2 flow rate is researched and the influencing mechanism is discussed. - Abstract: 3C-SiC thin films were grown on Si(111) substrates at 1250 °C by horizontal low pressure chemical vapor deposition (LPCVD). We performed an exhaustive study on the effect of H_2 flow rate on the crystalline quality, surface morphologies, growth rate, n-type doping of 3C-SiC thin films and the voids at the interface. The films show epitaxial nature with high crystal quality and surface morphology increase obviously with increasing H_2 flow rate. The growth rate and n-type doping are also dependent on H_2 flow rate. The properties of the voids at the interface are discussed based on the cross-sectional scanning electron microscope characterization. Transformation of voids with increasing H_2 flow rate are attributed to higher 3C-SiC film growth rate and H_2 etching rate. The mechanism of void formation is discussed based on our model, too. The results demonstrate that H_2 flow rate plays a very important role in the heteroepitaxial growth of 3C-SiC films.

  18. Effect of hydrogen flow on growth of 3C-SiC heteroepitaxial layers on Si(111) substrates

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Guoguo [Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Zhang, Feng, E-mail: fzhang@semi.ac.cn [Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Niu, Yingxi; Yang, Fei [Electrical Engineering New Materials and Microelectronics Department, State Grid Smart Grid Research Institute, Beijing 100192 (China); Liu, Xingfang; Wang, Lei; Zhao, Wanshun [Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Sun, Guosheng [Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Dongguan Tianyu Semiconductor, Inc., Dongguan 523000 (China); Zeng, Yiping [Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)

    2015-10-30

    Highlights: • 3C-SiC thin films of preferential orientation along with Si(111) substrates were obtained using home-made horizontal LPCVD with different H{sub 2} flow rate ranging from15 to 30 slm. • High H{sub 2} flow rate will inhibit the out-diffusion of silicon atoms from silicon substrates effectively. Transformation and the mechanism of void formation are discussed based on our model. • The variation of growth rate and n-type doping with increasing H{sub 2} flow rate is researched and the influencing mechanism is discussed. - Abstract: 3C-SiC thin films were grown on Si(111) substrates at 1250 °C by horizontal low pressure chemical vapor deposition (LPCVD). We performed an exhaustive study on the effect of H{sub 2} flow rate on the crystalline quality, surface morphologies, growth rate, n-type doping of 3C-SiC thin films and the voids at the interface. The films show epitaxial nature with high crystal quality and surface morphology increase obviously with increasing H{sub 2} flow rate. The growth rate and n-type doping are also dependent on H{sub 2} flow rate. The properties of the voids at the interface are discussed based on the cross-sectional scanning electron microscope characterization. Transformation of voids with increasing H{sub 2} flow rate are attributed to higher 3C-SiC film growth rate and H{sub 2} etching rate. The mechanism of void formation is discussed based on our model, too. The results demonstrate that H{sub 2} flow rate plays a very important role in the heteroepitaxial growth of 3C-SiC films.

  19. Rational growth of semi-polar ZnO texture on a glass substrate for optoelectronic applications

    Science.gov (United States)

    Lu, B.; Ma, M. J.; Ye, Y. H.; Lu, J. G.; He, H. P.; Ye, Z. Z.

    2013-02-01

    Semi-polar ZnO films with surface texture were grown on glass substrates via pulsed-laser deposition (PLD) through Co-Ga co-doping. Oxygen pressure (PO2) was found to have significant effects on the structural and optical properties of the Zn(Co, Ga)O (ZCGO) films. A self-textured film with (1\\,0\\,\\bar {1}\\,1) preferred orientation (PO) was achieved by varying the growth conditions including a crucial narrow PO2 window and growth time. A possible mechanism underlying the PO evolution and the final texture of the films was proposed, which can be attributed to the collaboration of the doping effect and the PO2-dependent evolutionary selection process, in which certain grains can have increased vertical growth rate with respect to the substrate surface through interplane diffusion. Moreover, the growth of undoped pure ZnO films proceeded by using the (1\\,0\\,\\bar {1}\\,1) ZCGO film as a buffer layer. The ZnO layers retained a semi-polar characteristic with improved crystallinity and better optical quality. The epitaxy-like orientation of ZnO layers grown on (1\\,0\\,\\bar {1}\\,1) ZCGO films has applications in the development of semi-polar ZnO-based light-emitting diodes.

  20. Stress-driven lithium dendrite growth mechanism and dendrite mitigation by electroplating on soft substrates

    Science.gov (United States)

    Wang, Xu; Zeng, Wei; Hong, Liang; Xu, Wenwen; Yang, Haokai; Wang, Fan; Duan, Huigao; Tang, Ming; Jiang, Hanqing

    2018-03-01

    Problems related to dendrite growth on lithium-metal anodes such as capacity loss and short circuit present major barriers to next-generation high-energy-density batteries. The development of successful lithium dendrite mitigation strategies is impeded by an incomplete understanding of the Li dendrite growth mechanisms, and in particular, Li-plating-induced internal stress in Li metal and its effect on Li growth morphology are not well addressed. Here, we reveal the enabling role of plating residual stress in dendrite formation through depositing Li on soft substrates and a stress-driven dendrite growth model. We show that dendrite growth is mitigated on such soft substrates through surface-wrinkling-induced stress relaxation in the deposited Li film. We demonstrate that this dendrite mitigation mechanism can be utilized synergistically with other existing approaches in the form of three-dimensional soft scaffolds for Li plating, which achieves higher coulombic efficiency and better capacity retention than that for conventional copper substrates.

  1. Three-dimensional growth simulation: A study of substrate oriented films

    International Nuclear Information System (INIS)

    Besnard, A; Martin, N; Carpentier, L

    2010-01-01

    Monte Carlo simulations are developed to simulate the growth of three-dimensional columnar microstructure in thin films. We are studying in particular oriented microstructure like those produced with the Glancing Angle Deposition technique (GLAD). Some geometrical characteristics of the particles flux, the organization of defect sites on the substrate surface and the atomic surface diffusion are mainly investigated in order to predict the growth processes and the resulting features of the films. This study reports on simulations of thin film growth exhibiting an oblique and zigzag columnar microstructure. Column angle evolution and density are investigated versus incidence angle α or period number n and compared with experimental measurements.

  2. Substrate temperature dependence of microcrystallinity in plasma-deposited, boron-doped hydrogenated silicon alloys

    International Nuclear Information System (INIS)

    Rajeswaran, G.; Kampas, F.J.; Vanier, P.E.; Sabatini, R.L.; Tafto, J.

    1983-01-01

    The glow-discharge decomposition of silane diluted in hydrogen using diborane as a dopant results in the deposition of p-type microcrystalline silicon films at relatively low temperatures. The conductivity of these films is critically dependent on the substrate temperature when the ratio of silane flow rate to total gas flow rate is 1%. Electron micrographs show that highly conducting films contain numerous clusters of 2.5-nm crystallites that are embedded in an amorphous medium

  3. Modeling gravity effects on water retention and gas transport characteristics in plant growth substrates

    DEFF Research Database (Denmark)

    Deepagoda Thuduwe Kankanamge Kelum, Chamindu; Jones, Scott B.; Tuller, Markus

    2014-01-01

    utilization to conserve energy and to limit transport costs, native materials mined on Moon or Mars are of primary interest for plant growth media in a future outpost, while terrestrial porous substrates with optimal growth media characteristics will be useful for onboard plant growth during space missions....... Due to limited experimental opportunities and prohibitive costs, liquid and gas behavior in porous substrates under reduced gravity conditions has been less studied and hence remains poorly understood. Based on ground-based measurements, this study examined water retention, oxygen diffusivity and air...... that estimates the gas percolation threshold based on the pore size distribution. The model successfully captured measured data for all investigated media and demonstrated the implications of the poorly-understood shift in gas percolation threshold with improved gas percolation in reduced gravity. Finally, using...

  4. Epitaxial growth of AlN on single crystal Mo substrates

    International Nuclear Information System (INIS)

    Okamoto, Koichiro; Inoue, Shigeru; Nakano, Takayuki; Kim, Tae-Won; Oshima, Masaharu; Fujioka, Hiroshi

    2008-01-01

    We have grown AlN films on single-crystalline Mo(110), (100), and (111) substrates using a low temperature pulsed laser deposition (PLD) growth technique and investigated their structural properties. Although c-axis oriented AlN films grow on Mo(100), the films contain 30 o rotated domains due to the difference in the rotational symmetry between AlN(0001) and Mo(100). AlN films with only poor crystalline quality grow on Mo(111) substrates, probably due to the poor surface morphology and high reactivity of the substrates. On the other hand, single crystal AlN films grow epitaxially on Mo(110) substrates with an in-plane relationship of AlN[11-20] // Mo[001]. Reflection high-energy electron diffraction or electron backscattered diffraction analysis has revealed that neither in-plane 30 deg. rotated domains nor cubic phase domains exist in the AlN films. X-ray reflectivity measurements have revealed that the heterointerface between AlN and Mo prepared by PLD at 450 deg. C is quite abrupt. These results indicate that PLD epitaxial growth of AlN on single crystal Mo substrates is quite promising for the fabrication of future high frequency filter devices

  5. Epitaxial growth of AlN on single crystal Mo substrates

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, Koichiro; Inoue, Shigeru [Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505 (Japan); Nakano, Takayuki; Kim, Tae-Won [Kanagawa Academy of Science and Technology (KAST) KSP east 301, 3-2-1 Sakado, Takatsu-ku, Kawasaki, Kanagawa, 213-0012 (Japan); Oshima, Masaharu [Department of Applied Chemistry, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656 (Japan); Fujioka, Hiroshi [Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505 (Japan); Kanagawa Academy of Science and Technology (KAST) KSP east 301, 3-2-1 Sakado, Takatsu-ku, Kawasaki, Kanagawa, 213-0012 (Japan)], E-mail: hfujioka@iis.u-tokyo.ac.jp

    2008-06-02

    We have grown AlN films on single-crystalline Mo(110), (100), and (111) substrates using a low temperature pulsed laser deposition (PLD) growth technique and investigated their structural properties. Although c-axis oriented AlN films grow on Mo(100), the films contain 30{sup o} rotated domains due to the difference in the rotational symmetry between AlN(0001) and Mo(100). AlN films with only poor crystalline quality grow on Mo(111) substrates, probably due to the poor surface morphology and high reactivity of the substrates. On the other hand, single crystal AlN films grow epitaxially on Mo(110) substrates with an in-plane relationship of AlN[11-20] // Mo[001]. Reflection high-energy electron diffraction or electron backscattered diffraction analysis has revealed that neither in-plane 30 deg. rotated domains nor cubic phase domains exist in the AlN films. X-ray reflectivity measurements have revealed that the heterointerface between AlN and Mo prepared by PLD at 450 deg. C is quite abrupt. These results indicate that PLD epitaxial growth of AlN on single crystal Mo substrates is quite promising for the fabrication of future high frequency filter devices.

  6. [Nutrient transfer and growth of Pinus greggii Engelm. inoculated with edible ectomycorrhizal mushrooms in two substrates].

    Science.gov (United States)

    Rentería-Chávez, María C; Pérez-Moreno, Jesús; Cetina-Alcalá, Víctor M; Ferrera-Cerrato, Ronald; Xoconostle-Cázares, Beatriz

    An ectomycorrhiza is a mutualistic symbiosis of paramount importance in forestry and tree production. One of the selection criteria of ectomycorrhizal fungi that has currently gained importance is their edibility due to the economic, ecological and cultural relevance of edible ectomycorrhizal mushrooms as a non-timber forest product. The effect of the inoculation with three edible ectomycorrhizal mushrooms: Laccaria laccata, Laccaria bicolor y Hebeloma leucosarx, which are widely sold in Mexico, on the growth and nutrient contents of Pinus greggii grown in an experimental substrate and a commercial substrate enriched with a slow-release fertilizer, was evaluated. Two years after sowing, differences in terms of shoot and root biomass and macro and micronutrient contents between inoculated and non-inoculated plants, were recorded independently of the fungal species and the substrate. Despite the fact that plants grown in the commercial substrate had higher growth and nutrient contents, their ectomycorrhizal colonization percentages were smaller than those of the plants grown in the experimental substrate. The differences in the nutrient transfer to the inoculated plant shoots among the evaluated fungal species were recorded. Ca mobilization by L. laccata, Na by L. bicolor and Mn by H. leucosarx were observed in the plants growing in the experimental substrate. It has been demonstrated that the selection of substrates constitutes an important factor in the production of ectomycorrhizal plants and that the three evaluated species of edible ectomycorrhizal mushrooms have an enormous potential in the controlled mycorrhization of P. greggii. Copyright © 2017 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  7. Substrate dependent physical properties of evaporated CdO thin films for optoelectronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Purohit, Anuradha; Chander, S.; Patel, S.L. [Department of Physics, Mohanlal Sukhadia University, Udaipur-313001 (India); Rangra, K.J. [Sensors and Transducers Group, CSIR-CEERI, Pilani-333031 (India); Dhaka, M.S., E-mail: msdhaka75@yahoo.co.in [Department of Physics, Mohanlal Sukhadia University, Udaipur-313001 (India)

    2017-06-15

    Highlights: • Substrate dependent physical properties of CdO thin films are carried out. • XRD patterns reveal that the films have cubic structure of space group Fm3m. • Optical direct band gap is found to vary with the substrates. • SEM images show that the films are compact and homogeneous. • I–V characteristics show ohmic behavior of the deposited CdO films. - Abstract: In this study, CdO thin films were grown by e-beam evaporation technique on glass, indium tin oxide (ITO), fluorine-doped tin oxide (FTO) and silicon (Si) wafer. The deposited films were analyzed by X-ray diffraction (XRD), UV–Vis spectrophotometer, scanning electron microscopy, energy dispersive spectroscopy (EDS) and source meter (current–voltage) for structural, optical, surface morphological, elemental and electrical analysis, respectively. The films have single phase of cubic structure (space group Fm3m) with (200) preferred orientation. The structural parameters viz. inter-planar spacing, grain size, lattice constant, internal strain and dislocation density are calculated and found to vary with the nature of the substrates. The optical band gap was found in the range 2.24–3.95 eV and strongly dependents on the substrates. The SEM analysis shows that the films are compact, homogeneous and have granular structure without any defects like pin holes and cracks. The EDS spectra confirmed the presence of cadmium (Cd) and oxygen (O) in the films deposited on different substrates. The current–voltage characteristics of the films show ohmic behavior.

  8. Direct growth of nanocrystalline hexagonal boron nitride films on dielectric substrates

    Energy Technology Data Exchange (ETDEWEB)

    Tay, Roland Yingjie [School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, Singapore 639798 (Singapore); Temasek Laboratories@NTU, 50 Nanyang Avenue, Singapore, Singapore 639798 (Singapore); Tsang, Siu Hon [Temasek Laboratories@NTU, 50 Nanyang Avenue, Singapore, Singapore 639798 (Singapore); Loeblein, Manuela; Chow, Wai Leong [School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, Singapore 639798 (Singapore); CNRS-International NTU Thales Research Alliance CINTRA UMI 3288, Research Techno Plaza, 50 Nanyang Drive, Singapore, Singapore 637553 (Singapore); Loh, Guan Chee [Institue of High Performance Computing, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632 (Singapore); Department of Physics, Michigan Technological University, Houghton, Michigan 49931 (United States); Toh, Joo Wah; Ang, Soon Loong [School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, Singapore 639798 (Singapore); Teo, Edwin Hang Tong, E-mail: htteo@ntu.edu.sg [School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, Singapore 639798 (Singapore); School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, Singapore 639798 (Singapore)

    2015-03-09

    Atomically thin hexagonal-boron nitride (h-BN) films are primarily synthesized through chemical vapor deposition (CVD) on various catalytic transition metal substrates. In this work, a single-step metal-catalyst-free approach to obtain few- to multi-layer nanocrystalline h-BN (NCBN) directly on amorphous SiO{sub 2}/Si and quartz substrates is demonstrated. The as-grown thin films are continuous and smooth with no observable pinholes or wrinkles across the entire deposited substrate as inspected using optical and atomic force microscopy. The starting layers of NCBN orient itself parallel to the substrate, initiating the growth of the textured thin film. Formation of NCBN is due to the random and uncontrolled nucleation of h-BN on the dielectric substrate surface with no epitaxial relation, unlike on metal surfaces. The crystallite size is ∼25 nm as determined by Raman spectroscopy. Transmission electron microscopy shows that the NCBN formed sheets of multi-stacked layers with controllable thickness from ∼2 to 25 nm. The absence of transfer process in this technique avoids any additional degradation, such as wrinkles, tears or folding and residues on the film which are detrimental to device performance. This work provides a wider perspective of CVD-grown h-BN and presents a viable route towards large-scale manufacturing of h-BN substrates and for coating applications.

  9. a-Si:H crystallization from isothermal annealing and its dependence on the substrate used

    Energy Technology Data Exchange (ETDEWEB)

    Rojas-Lopez, M., E-mail: marlonrl@yahoo.com.mx [CIBA-Tlaxcala, Instituto Politecnico Nacional, Tepetitla, Tlax. 90700 (Mexico); Orduna-Diaz, A.; Delgado-Macuil, R.; Gayou, V.L.; Bibbins-Martinez, M. [CIBA-Tlaxcala, Instituto Politecnico Nacional, Tepetitla, Tlax. 90700 (Mexico); Torres-Jacome, A.; Trevino-Palacios, C.G. [INAOE, Tonantzintla, Puebla, Pue. 72000 (Mexico)

    2010-10-25

    We present hydrogenated amorphous silicon (a-Si:H) films which were deposited on two different substrates (glass and mono-crystalline silicon) after an isothermal annealing treatment at 250 deg. C for up to 14 h. The annealed amorphous films were analyzed using atomic force microscopy, Raman and FTIR spectroscopy. Films deposited on glass substrate experienced an amorphous-crystalline phase transition after annealing because of the metal-induced crystallization effect, reaching approximately 70% conversion after 14 h of annealing. An absorption frequency of the TO-phonon mode that varies systematically with the substoichiometry of the silicon oxide in the 1046-1170 cm{sup -1} region was observed, revealing the reactivity of the film with the annealing time. For similar annealing time, films deposited on mono-crystalline silicon substrate remained mainly amorphous with minimal Si-crystalline formation. Therefore, the crystalline formations and the shape of the films surfaces depends on the annealing time as well as on the substrate employed during the deposition process of the a-Si:H film.

  10. Thermal oxidation of seeds for the hydrothermal growth of WO3 nanorods on ITO glass substrate

    International Nuclear Information System (INIS)

    Ng, Chai Yan; Abdul Razak, Khairunisak; Lockman, Zainovia

    2015-01-01

    This work reports a simple seed formation method for the hydrothermal growth of tungsten oxide (WO 3 ) nanorods. A WO 3 seed layer was prepared by thermal oxidation, where a W-sputtered substrate was heated and oxidized in a furnace. Oxidation temperatures and periods were varied at 400–550 °C and 5–60 min, respectively, to determine an appropriate seed layer for nanorod growth. Thermal oxidation at 500 °C for 15 min was found to produce a seed layer with sufficient crystallinity and good adhesion to the substrate. These properties prevented the seed from peeling off during the hydrothermal process, thereby allowing nanorod growth on the seed. The nanorod film showed better electrochromic behavior (higher current density of − 1.11 and + 0.65 mA cm −2 ) than compact film (lower current density of − 0.54 and + 0.28 mA cm −2 ). - Highlights: • A simple seed formation method (thermal oxidation) on sputtered W film is reported. • Crystalline seed with good adhesion to substrate is required for nanorod growth. • The appropriate temperature and period for seed formation were 500 °C and 15 min. • WO 3 nanorods exhibited higher electrochromic current density than WO 3 compact film.

  11. Localized Technological Change and Path-Dependent Growth

    OpenAIRE

    Bassanini, A.

    1997-01-01

    In recent years the theory of macroeconomic growth has seen an expanding literature building upon the idea that technological change is localized (technology-specific) to investigate various phenomena such as leapfrogging, take-off, and social mobility. In this paper I explore the relationship between localized technological change and dependence on history of long-run aggregate output growth. The growth model I set forth show that, subject to mild assumptions on the stochastic process repres...

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

    Science.gov (United States)

    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.

  13. Homo-epitaxial diamond film growth on ion implanted diamond substrates

    Energy Technology Data Exchange (ETDEWEB)

    Weiser, P.S.; Prawer, S.; Nugent, K.W.; Bettiol, A.A.; Kostidis, L.I.; Jamieson, D.N. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    The nucleation of CVD diamond is a complicated process, governed by many interrelated parameters. In the present work we attempt to elucidate the effect of strain on the growth of a homo-epitaxial CVD diamond. We have employed laterally confined high dose (MeV) Helium ion implantation to produce surface swelling of the substrate. The strain is enhanced by the lateral confinement of the implanted region to squares of 100 x 100 {mu}m{sup 2}. After ion implantation, micro-Raman spectroscopy was employed to map the surface strain. The substrates were then inserted into a CVD reactor and a CVD diamond film was grown upon them. Since the strained regions were laterally confined, it was then possible to monitor the effect of strain on diamond nucleation. The substrates were also analysed using Rutherford Backscattering Spectroscopy (RBS), Proton induced X-ray Emission (PIXE) and Ion Beam induced Luminescence (IBIL). 7 refs., 5 figs.

  14. Diamond film growth with modification properties of adhesion between substrate and diamond film

    Directory of Open Access Journals (Sweden)

    Setasuwon P.

    2004-03-01

    Full Text Available Diamond film growth was studied using chemical vapor deposition (CVD. A special equipment was build in-house, employing a welding torch, and substrate holder with a water-cooling system. Acetylene and oxygen were used as combustion gases and the substrate was tungsten carbide cobalt. It was found that surface treatments, such as diamond powder scratching or acid etching, increase the adhesion and prevent the film peel-off. Diamond powder scratching and combined diamond powder scratching with acid etching gave the similar diamond film structure with small grain and slightly rough surface. The diamond film obtained with both treatments has high adhesion and can withstand internal stress better than ones obtained by untreated surface or acid etching alone. It was also found that higher substrate temperature produced smoother surface and more uniform diamond grain.

  15. Heteroepitaxial Growth of Ferromagnetic MnSb(0001) Films on Ge/Si(111) Virtual Substrates.

    Science.gov (United States)

    Burrows, Christopher W; Dobbie, Andrew; Myronov, Maksym; Hase, Thomas P A; Wilkins, Stuart B; Walker, Marc; Mudd, James J; Maskery, Ian; Lees, Martin R; McConville, Christopher F; Leadley, David R; Bell, Gavin R

    2013-11-06

    Molecular beam epitaxial growth of ferromagnetic MnSb(0001) has been achieved on high quality, fully relaxed Ge(111)/Si(111) virtual substrates grown by reduced pressure chemical vapor deposition. The epilayers were characterized using reflection high energy electron diffraction, synchrotron hard X-ray diffraction, X-ray photoemission spectroscopy, and magnetometry. The surface reconstructions, magnetic properties, crystalline quality, and strain relaxation behavior of the MnSb films are similar to those of MnSb grown on GaAs(111). In contrast to GaAs substrates, segregation of substrate atoms through the MnSb film does not occur, and alternative polymorphs of MnSb are absent.

  16. Homo-epitaxial diamond film growth on ion implanted diamond substrates

    Energy Technology Data Exchange (ETDEWEB)

    Weiser, P S; Prawer, S; Nugent, K W; Bettiol, A A; Kostidis, L I; Jamieson, D N [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1997-12-31

    The nucleation of CVD diamond is a complicated process, governed by many interrelated parameters. In the present work we attempt to elucidate the effect of strain on the growth of a homo-epitaxial CVD diamond. We have employed laterally confined high dose (MeV) Helium ion implantation to produce surface swelling of the substrate. The strain is enhanced by the lateral confinement of the implanted region to squares of 100 x 100 {mu}m{sup 2}. After ion implantation, micro-Raman spectroscopy was employed to map the surface strain. The substrates were then inserted into a CVD reactor and a CVD diamond film was grown upon them. Since the strained regions were laterally confined, it was then possible to monitor the effect of strain on diamond nucleation. The substrates were also analysed using Rutherford Backscattering Spectroscopy (RBS), Proton induced X-ray Emission (PIXE) and Ion Beam induced Luminescence (IBIL). 7 refs., 5 figs.

  17. Homo-epitaxial diamond film growth on ion implanted diamond substrates

    International Nuclear Information System (INIS)

    Weiser, P.S.; Prawer, S.; Nugent, K.W.; Bettiol, A.A.; Kostidis, L.I.; Jamieson, D.N.

    1996-01-01

    The nucleation of CVD diamond is a complicated process, governed by many interrelated parameters. In the present work we attempt to elucidate the effect of strain on the growth of a homo-epitaxial CVD diamond. We have employed laterally confined high dose (MeV) Helium ion implantation to produce surface swelling of the substrate. The strain is enhanced by the lateral confinement of the implanted region to squares of 100 x 100 μm 2 . After ion implantation, micro-Raman spectroscopy was employed to map the surface strain. The substrates were then inserted into a CVD reactor and a CVD diamond film was grown upon them. Since the strained regions were laterally confined, it was then possible to monitor the effect of strain on diamond nucleation. The substrates were also analysed using Rutherford Backscattering Spectroscopy (RBS), Proton induced X-ray Emission (PIXE) and Ion Beam induced Luminescence (IBIL). 7 refs., 5 figs

  18. Density-dependent growth in invasive Lionfish (Pterois volitans).

    Science.gov (United States)

    Benkwitt, Cassandra E

    2013-01-01

    Direct demographic density dependence is necessary for population regulation and is a central concept in ecology, yet has not been studied in many invasive species, including any invasive marine fish. The red lionfish (Pterois volitans) is an invasive predatory marine fish that is undergoing exponential population growth throughout the tropical western Atlantic. Invasive lionfish threaten coral-reef ecosystems, but there is currently no evidence of any natural population control. Therefore, a manipulative field experiment was conducted to test for density dependence in lionfish. Juvenile lionfish densities were adjusted on small reefs and several demographic rates (growth, recruitment, immigration, and loss) were measured throughout an 8-week period. Invasive lionfish exhibited direct density dependence in individual growth rates, as lionfish grew slower at higher densities throughout the study. Individual growth in length declined linearly with increasing lionfish density, while growth in mass declined exponentially with increasing density. There was no evidence, however, for density dependence in recruitment, immigration, or loss (mortality plus emigration) of invasive lionfish. The observed density-dependent growth rates may have implications for which native species are susceptible to lionfish predation, as the size and type of prey that lionfish consume is directly related to their body size. The absence of density-dependent loss, however, contrasts with many native coral-reef fish species and suggests that for the foreseeable future manual removals may be the only effective local control of this invasion.

  19. Density-dependent growth in invasive Lionfish (Pterois volitans.

    Directory of Open Access Journals (Sweden)

    Cassandra E Benkwitt

    Full Text Available Direct demographic density dependence is necessary for population regulation and is a central concept in ecology, yet has not been studied in many invasive species, including any invasive marine fish. The red lionfish (Pterois volitans is an invasive predatory marine fish that is undergoing exponential population growth throughout the tropical western Atlantic. Invasive lionfish threaten coral-reef ecosystems, but there is currently no evidence of any natural population control. Therefore, a manipulative field experiment was conducted to test for density dependence in lionfish. Juvenile lionfish densities were adjusted on small reefs and several demographic rates (growth, recruitment, immigration, and loss were measured throughout an 8-week period. Invasive lionfish exhibited direct density dependence in individual growth rates, as lionfish grew slower at higher densities throughout the study. Individual growth in length declined linearly with increasing lionfish density, while growth in mass declined exponentially with increasing density. There was no evidence, however, for density dependence in recruitment, immigration, or loss (mortality plus emigration of invasive lionfish. The observed density-dependent growth rates may have implications for which native species are susceptible to lionfish predation, as the size and type of prey that lionfish consume is directly related to their body size. The absence of density-dependent loss, however, contrasts with many native coral-reef fish species and suggests that for the foreseeable future manual removals may be the only effective local control of this invasion.

  20. Bacterial growth and substrate degradation by BTX-oxidizing culture in response to salt stress.

    Science.gov (United States)

    Lee, Chi-Yuan; Lin, Ching-Hsing

    2006-01-01

    Interactions between microbial growth and substrate degradation are important in determining the performance of trickle-bed bioreactors (TBB), especially when salt is added to reduce biomass formation in order to alleviate media clogging. This study was aimed at quantifying salinity effects on bacterial growth and substrate degradation, and at acquiring kinetic information in order to improve the design and operation of TBB. Experiment works began by cultivating a mixed culture in a chemostat reactor receiving artificial influent containing a mixture of benzene, toluene, and xylene (BTX), followed by using the enrichment culture to degrade the individual BTX substrates under a particular salinity, which ranged 0-50 g l(-1) in batch mode. Then, the measured concentrations of biomass and residual substrate versus time were analyzed with the microbial kinetics; moreover, the obtained microbial kinetic constants under various salinities were modeled using noncompetitive inhibition kinetics. For the three substrates the observed bacterial yields appeared to be decreased from 0.51-0.74 to 0.20-0.22 mg mg(-1) and the maximum specific rate of substrate utilization, q, declined from 0.25-0.42 to 0.07-0.11 h(-1), as the salinity increased from 0 to 50 NaCl g l(-1). The NaCl acted as noncompetitive inhibitor, where the modeling inhibitions of the coefficients, K ( T(S)), were 22.7-29.7 g l(-1) for substrate degradation and K ( T(mu)), 13.0-19.0 g l(-1), for biomass formation. The calculated ratios for the bacterial maintenance rate, m (S), to q, further indicated that the percentage energy spent on maintenance increased from 19-24 to 86-91% as salinity level increased from 0 to 50 g l(-1). These results revealed that the bacterial growth was more inhibited than substrate degradation by the BTX oxidizers under the tested salinity levels. The findings from this study demonstrate the potential of applying NaCl salt to control excessive biomass formation in biotrickling filters.

  1. EFFECT OF PLANT EXTRACTS AND GROWTH SUBSTRATES ON CONTROLLING DAMPING-OFF IN PINUS TECUNUMANII SEEDLINGS

    Directory of Open Access Journals (Sweden)

    Maria Alejandra Fajardo-Mejía

    2016-09-01

    Full Text Available Damping-off is considered one of the most limiting phytosanitary problems in conifer seedling production because it may cause massive damage or total plant death in short time periods. This pathology is caused by a complex of microorganisms, the most common of which are Fusarium spp. and Rhizoctonia spp. This study evaluated the effect of growth substrates and plant extracts at different concentrations on germination and incidence of disease in Pinus tecunumanii plants. The plants were inoculated with the damping-off pathogen Fusarium oxysporum and treatments were applied in a completely randomized design with a factorial arrangement of 4x2x3. This corresponded to four substrates (pine bark, rice hull, coconut husk and sandy soil (4:1; two plant extracts (Matricaria chamomilla and Datura stramonium, andthree concentrations of each extract (Control concentration: 0%, Concentration 1: 50 % and Concentration 2: Undiluted. Each treatment had three repetitions, with 25 plants per repetition. The growth substrates affected germination; the most effective of these were sandy soil (4:1 and pine bark, with 90% and 92% germination at day 20, respectively. No significant difference was observed between the germination obtained with these substrates and that obtained with coconut husk after day 19. Meanwhile, all of the extracts had a significant effect on controlling the disease when they were combined with the substrates, with the exception of coconut husk. With this last substrate the incidence of disease was lower than 4% without the application of plant extracts; this indicates that coconut husk discourages the development of the disease on its own.

  2. Differential growth responses of soil bacterial taxa to carbon substrates of varying chemical recalcitrance

    Energy Technology Data Exchange (ETDEWEB)

    Goldfarb, K.C.; Karaoz, U.; Hanson, C.A.; Santee, C.A.; Bradford, M.A.; Treseder, K.K.; Wallenstein, M.D.; Brodie, E.L.

    2011-04-18

    Soils are immensely diverse microbial habitats with thousands of co-existing bacterial, archaeal, and fungal species. Across broad spatial scales, factors such as pH and soil moisture appear to determine the diversity and structure of soil bacterial communities. Within any one site however, bacterial taxon diversity is high and factors maintaining this diversity are poorly resolved. Candidate factors include organic substrate availability and chemical recalcitrance, and given that they appear to structure bacterial communities at the phylum level, we examine whether these factors might structure bacterial communities at finer levels of taxonomic resolution. Analyzing 16S rRNA gene composition of nucleotide analog-labeled DNA by PhyloChip microarrays, we compare relative growth rates on organic substrates of increasing chemical recalcitrance of >2,200 bacterial taxa across 43 divisions/phyla. Taxa that increase in relative abundance with labile organic substrates (i.e., glycine, sucrose) are numerous (>500), phylogenetically clustered, and occur predominantly in two phyla (Proteobacteria and Actinobacteria) including orders Actinomycetales, Enterobacteriales, Burkholderiales, Rhodocyclales, Alteromonadales, and Pseudomonadales. Taxa increasing in relative abundance with more chemically recalcitrant substrates (i.e., cellulose, lignin, or tannin-protein) are fewer (168) but more phylogenetically dispersed, occurring across eight phyla and including Clostridiales, Sphingomonadalaes, Desulfovibrionales. Just over 6% of detected taxa, including many Burkholderiales increase in relative abundance with both labile and chemically recalcitrant substrates. Estimates of median rRNA copy number per genome of responding taxa demonstrate that these patterns are broadly consistent with bacterial growth strategies. Taken together, these data suggest that changes in availability of intrinsically labile substrates may result in predictable shifts in soil bacterial composition.

  3. Substrate mediated growth of organic semiconducting thin films; Templateffekte bei der Strukturierung organischer Halbleiterfilme

    Energy Technology Data Exchange (ETDEWEB)

    Goetzen, Jan

    2010-09-17

    Since electronic properties of molecular materials are closely related to their structural order a precise control of the molecular packing and crystalline orientation of thin films is of vital interest for an optimization of organic electronic devices. Of particular interest in this respect is the initial stage of film formation which is largely governed by the interplay of intermolecular and molecule-substrate interactions. One approach to control the molecular film structure is based on substrate mediated growth. In this respect we have studied structural properties of thin films of pentacene, pentacene- 5,7,12,14-tetrone and perfluoro-pentacene which were grown onto various substrates including metals, metal oxides and graphite. On metal surfaces the molecules initially form a chemisorbed monolayer where molecules even can be uniformly aligned when using appropriate substrates with twofold symmetry. Further deposition, however, is accompanied by a pronounced dewetting and formation of disjoined islands which results from a large structural mismatch between the molecular arrangement in the monolayer and the crystalline phase. In some cases it is possible to orient such islands by utilizing step mediated nucleation and decoration of step bunches which allows the preparation of azimuthally well oriented elongated islands. On single crystalline oxides the growth parallels the situation found before for SiO{sub 2} where islands of upright oriented molecules are formed. The growth on graphite is somewhat particular since the lattice provides a natural template for acenes yielding epitaxially ordered monolayer films with planar adsorption geometry like in case of metals. Interestingly, however, no dewetting occurs upon further growth and instead rather smooth films are formed. The detailed analysis for the case of pentacene showed that the substrate-molecule interaction actually is weaker than the intermolecular interaction so that multilayer films can lift the

  4. Twin-assisted growth of nominally stable substrates underneath dewetted Au nanoparticles

    International Nuclear Information System (INIS)

    Liu, Fang; Xie, Dong Yue; Majdi, Tahereh; Zhu, Guo-zhen

    2016-01-01

    By applying a simple and inexpensive thermal treatment, we synthesized supported gold-oxide nanostructures, which have potential applications to plasmonic devices and biosensors. The regrowth of nominally stable substrates under gold nanoparticles is associated with the appearance of preferential orientations of dewetted nanoparticles and the formation of atomically sharp interfacial monolayers. Steps present at the interfacial monolayer usually occur at defects including the intersection points of twin planes at the interface. They were related to the nucleation and immigration of the interfacial monolayers, prompting the substrate regrowth. Accordingly, we proposed the twin-assisted growth mechanism, which provides insight on the synthesis of gold-oxide nanostructures. - Highlights: • The twin-assisted growth mechanism is proposed for the abnormal regrowth of substrate underneath Au nanoparticles. • The substrate regrowth is related to the steps and ledges that are present at the Au–MgAl_2O_4 interfacial monolayers. • Interfacial steps are detected at defects such as the intersecting points of twin planes at the interface.

  5. Twin-assisted growth of nominally stable substrates underneath dewetted Au nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Fang; Xie, Dong Yue [State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240 (China); Majdi, Tahereh [Department of Engineering Physics, McMaster University, 1280 Main St. W., Hamilton, ON L8S 4L7 (Canada); Zhu, Guo-zhen, E-mail: zhugz@sjtu.edu.cn [State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240 (China)

    2016-03-15

    By applying a simple and inexpensive thermal treatment, we synthesized supported gold-oxide nanostructures, which have potential applications to plasmonic devices and biosensors. The regrowth of nominally stable substrates under gold nanoparticles is associated with the appearance of preferential orientations of dewetted nanoparticles and the formation of atomically sharp interfacial monolayers. Steps present at the interfacial monolayer usually occur at defects including the intersection points of twin planes at the interface. They were related to the nucleation and immigration of the interfacial monolayers, prompting the substrate regrowth. Accordingly, we proposed the twin-assisted growth mechanism, which provides insight on the synthesis of gold-oxide nanostructures. - Highlights: • The twin-assisted growth mechanism is proposed for the abnormal regrowth of substrate underneath Au nanoparticles. • The substrate regrowth is related to the steps and ledges that are present at the Au–MgAl{sub 2}O{sub 4} interfacial monolayers. • Interfacial steps are detected at defects such as the intersecting points of twin planes at the interface.

  6. Enhancing trichloroethylene degradation using non-aromatic compounds as growth substrates.

    Science.gov (United States)

    Kim, Seungjin; Hwang, Jeongmin; Chung, Jinwook; Bae, Wookeun

    2014-06-30

    The effect of non-aromatic compounds on the trichloroethylene (TCE) degradation of toluene-oxidizing bacteria were evaluated using Burkholderia cepacia G4 that expresses toluene 2-monooxygenase and Pseudomonas putida that expresses toluene dioxygenase. TCE degradation rates for B. cepacia G4 and P. putida with toluene alone as growth substrate were 0.144 and 0.123 μg-TCE/mg-protein h, respectively. When glucose, acetate and ethanol were fed as additional growth substrates, those values increased up to 0.196, 0.418 and 0.530 μg-TCE/mg-protein h, respectively for B. cepacia G4 and 0.319, 0.219 and 0.373 μg-TCE/mg-protein h, respectively for P. putida. In particular, the addition of ethanol resulted in a high TCE degradation rate regardless of the initial concentration. The use of a non-aromatic compound as an additional substrate probably enhanced the TCE degradation because of the additional supply of NADH that is consumed in co-metabolic degradation of TCE. Also, it is expected that the addition of a non-aromatic substrate can reduce the necessary dose of toluene and, subsequently, minimize the potential competitive inhibition upon TCE co-metabolism by toluene. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Effect of different substrates on growth of Mimosa bimucronata seedlings inoculate with rhizobium

    Directory of Open Access Journals (Sweden)

    Juliana Müller Freire

    2017-06-01

    Full Text Available The objective of this study was to evaluate the growth response of Mimosa bimucronata (DC O. Kuntze seedlings in nursery conditions to inoculation with rhizobium strains previously selected using different substrates. An experimental design of randomized blocks with split plots was used, testing three substrates (pure organic-containing clay, sand and manure in 1: 1: 1 v: v: v ratio; organomineral mixed with 30% straw and sand with vermiculite in 1: 1 v: v and four N sources (inoculation with strains BR 3461 and BR 3470, control with N fertilization and control without fertilization, totalizing 12 treatments. Height and stem diameter were evaluate after 90 days and shoot, root and nodules dry mass were evaluate after 120 days. Organomineral substrates provided better seedling growth. However, only organic-substrate with straw and sand with vermiculite showed positive responses of plants inoculated with BR3470 strain. The performance of the inoculated seedlings was not higher than that of seedlings fertilized with N. The rate of N applied stimulated nodulation rather than inhibit it.

  8. Dracaena marginata biofilter: design of growth substrate and treatment of stormwater runoff.

    Science.gov (United States)

    Vijayaraghavan, K; Praveen, R S

    2016-01-01

    The purpose of this research was to investigate the efficiency of Dracaena marginata planted biofilters to decontaminate urban runoff. A new biofilter growth substrate was prepared using low-cost and locally available materials such as red soil, fine sand, perlite, vermiculite, coco-peat and Sargassum biomass. The performance of biofilter substrate was compared with local garden soil based on physical and water quality parameters. Preliminary analyses indicated that biofilter substrate exhibited desirable characteristics such as low bulk density (1140 kg/m(3)), high water holding capacity (59.6%), air-filled porosity (7.82%) and hydraulic conductivity (965 mm/h). Four different biofilter assemblies, with vegetated and non-vegetated systems, were examined for several artificial rain events (un-spiked and metal-spiked). Results from un-spiked artificial rain events suggested that concentrations of most of the chemical components in effluent were highest at the beginning of rain events and thereafter subsided during the subsequent rain events. Biofilter growth substrate showed superior potential over garden soil to retain metal ions such as Al, Fe, Cu, Cr, Ni, Zn, Cd and Pb during metal-spiked rain events. Significant differences were also observed between non-vegetated and vegetated biofilter assemblies in runoff quality, with the latter producing better results.

  9. Growth and BZO-doping of the nanostructured YBCO thin films on buffered metal substrates

    DEFF Research Database (Denmark)

    Huhtinen, H.; Irjala, M.; Paturi, P.

    2010-01-01

    The growth of the nanostructured YBa2Cu3O6+x (YBCO) films is investigated for the first time on biaxially textured NiW substrates used in coated conductor technology. The optimization process of superconducting layers is made in wide magnetic field and temperature range in order to understand...... the vortex pinning structure and mechanism in our films prepared from nanostructured material. Structural analysis shows that growth mechanism in YBCO films grown on NiW is completely different when compared to YBCO on STO. Films on NiW are much rougher, there is huge in-plane variation of YBCO crystals...... and moreover out-of-plane long range lattice ordering is greatly reduced. Magnetic measurements demonstrate that jc in films grown on NiW is higher in high magnetic fields and low temperatures. This effect is connected to the amount of pinning centres observed in films on metal substrates which are effective...

  10. Growth and substrate consumption of Nitrobacter agilis cells immobilized in carrageenan: part 1. Dynamic modeling.

    Science.gov (United States)

    de Gooijer, C D; Wijffels, R H; Tramper, J

    1991-07-01

    The modeling of the growth of Nitrobacter agilis cell immobilized in kappa-carrageenan is presented. A detailed description is given of the modeling of internal diffusion and growth of cells in the support matrix in addition to external mass transfer resistance. The model predicts the substrate and biomass profiles in the support as well as the macroscopic oxygen consumption rate of the immobilized biocatalyst in time. The model is tested by experiments with continuously operated airlift loop reactors containing cells immobilized in kappa-carrageenan. The model describes experimental data very well. It is clearly shown that external mass transfer may not be neglected. Furthermore, a sensitivity analysis of the parameters at their values during the experiments revealed that apart from the radius of the spheres and the substrate bulk concentration, the external mass transfer resistance coefficient is the most sensitive parameter for our case.

  11. Growth of Horizonatal ZnO Nanowire Arrays on Any Substrate

    KAUST Repository

    Qin, Yong

    2008-12-04

    A general method is presented for growing laterally aligned and patterned ZnO nanowire (NW) arrays on any substrate as long as it is flat. The orientation control is achieved using the combined effect from ZnO seed layer and the catalytically inactive Cr (or Sn) layer for NW growth. The growth temperature (< 100 °C) is so low that the method can be applied to a wide range of substrates that can be inorganic, organic, single crystal, polycrystal, or amorphous. The laterally aligned ZnO NW arrays can be employed for various applications, such as gas sensor, field effect transistor, nanogenerator, and flexible electronics. © 2008 American Chemical Society.

  12. Growth of higher fungi on wheat straw and their impact on the digestibility of the substrate

    Energy Technology Data Exchange (ETDEWEB)

    Moyson, E.; Verachtert, H. (Catholic Univ. of Leuven (Belgium). Faculty of Agriculture)

    1991-12-01

    The influence of the growth of three higher fungi on the composition of wheat straw was investigated. Pleurotus pulmonarius, P. sajor-caju and Lentinus edodes grew very well on lignocellulosic substrates, breaking down a considerable amount of lignin. The initial lignin concentration of straw was halved after 12 weeks of fungal growth, doubling the enzymic digestibility. Together with lignin, the higher fungi consumed half of the amount of hemicellulose (i.e. 15%), leaving cellulose fairly intact, which should remain as an energy source for ruminants. (orig.).

  13. Growth of CNTs on Fe-Si catalyst prepared on Si and Al coated Si substrates

    International Nuclear Information System (INIS)

    Teng, F-Y; Ting, J-M; Sharma, Sahendra P; Liao, Kun-Hou

    2008-01-01

    In this paper we report the effect of Al interlayers on the growth characteristics of carbon nanotubes (CNTs) using as-deposited and plasma etched Fe-Si catalyst films as the catalysts. Al interlayers having various thicknesses ranging from 2 to 42 nm were deposited on Si substrates prior to the deposition of Fe-Si catalysts. It was found that the Al interlayer diffuses into the Fe-Si catalyst during the plasma etching prior to the CNT growth, leading to the swelling and amorphization of the catalyst. This allows enhanced carbon diffusion in the catalyst and therefore a faster growth rate of the resulting CNTs. It was also found that use of an Al interlayer having a thickness of ∼3 ± 1 nm is most effective. Due to the effectiveness of this, the normally required catalyst etching is no longer needed for the growth of CNTs

  14. Growth of CNTs on Fe-Si catalyst prepared on Si and Al coated Si substrates.

    Science.gov (United States)

    Teng, F-Y; Ting, Jyh-Ming; Sharma, Sahendra P; Liao, Kun-Hou

    2008-03-05

    In this paper we report the effect of Al interlayers on the growth characteristics of carbon nanotubes (CNTs) using as-deposited and plasma etched Fe-Si catalyst films as the catalysts. Al interlayers having various thicknesses ranging from 2 to 42 nm were deposited on Si substrates prior to the deposition of Fe-Si catalysts. It was found that the Al interlayer diffuses into the Fe-Si catalyst during the plasma etching prior to the CNT growth, leading to the swelling and amorphization of the catalyst. This allows enhanced carbon diffusion in the catalyst and therefore a faster growth rate of the resulting CNTs. It was also found that use of an Al interlayer having a thickness of ∼3 ± 1 nm is most effective. Due to the effectiveness of this, the normally required catalyst etching is no longer needed for the growth of CNTs.

  15. MOVPE growth of violet GaN LEDs on β-Ga2O3 substrates

    Science.gov (United States)

    Li, Ding; Hoffmann, Veit; Richter, Eberhard; Tessaro, Thomas; Galazka, Zbigniew; Weyers, Markus; Tränkle, Günther

    2017-11-01

    We report that a H2-free atmosphere is essential for the initial stage of metalorganic vapour phase epitaxy (MOVPE) growth of GaN on β-Ga2O3 to prevent the surface from damage. A simple growth method is proposed that can easily transfer established GaN growth recipes from sapphire to β-Ga2O3 with both (-2 0 1) and (1 0 0) orientations. This method features a thin AlN nucleation layer grown below 900 °C in N2 atmosphere to protect the surface of β-Ga2O3 from deterioration during further growth under the H2 atmosphere. Based on this, we demonstrate working violet vertical light emitting diodes (VLEDs) on n-conductive β-Ga2O3 substrates.

  16. Characterization of dependencies between growth and division in budding yeast.

    Science.gov (United States)

    Mayhew, Michael B; Iversen, Edwin S; Hartemink, Alexander J

    2017-02-01

    Cell growth and division are processes vital to the proliferation and development of life. Coordination between these two processes has been recognized for decades in a variety of organisms. In the budding yeast Saccharomyces cerevisiae , this coordination or 'size control' appears as an inverse correlation between cell size and the rate of cell-cycle progression, routinely observed in G 1 prior to cell division commitment. Beyond this point, cells are presumed to complete S/G 2 /M at similar rates and in a size-independent manner. As such, studies of dependence between growth and division have focused on G 1 Moreover, in unicellular organisms, coordination between growth and division has commonly been analysed within the cycle of a single cell without accounting for correlations in growth and division characteristics between cycles of related cells. In a comprehensive analysis of three published time-lapse microscopy datasets, we analyse both intra- and inter-cycle dependencies between growth and division, revisiting assumptions about the coordination between these two processes. Interestingly, we find evidence (i) that S/G 2 /M durations are systematically longer in daughters than in mothers, (ii) of dependencies between S/G 2 /M and size at budding that echo the classical G 1 dependencies, and (iii) in contrast with recent bacterial studies, of negative dependencies between size at birth and size accumulated during the cell cycle. In addition, we develop a novel hierarchical model to uncover inter-cycle dependencies, and we find evidence for such dependencies in cells growing in sugar-poor environments. Our analysis highlights the need for experimentalists and modellers to account for new sources of cell-to-cell variation in growth and division, and our model provides a formal statistical framework for the continued study of dependencies between biological processes. © 2017 The Author(s).

  17. Aminoacid polymorphisms of insulin receptor substrate-1 in non-insulin-dependent diabetes mellitus

    DEFF Research Database (Denmark)

    Almind, K; Bjørbaek, C; Vestergaard, H

    1993-01-01

    Since relative or absolute insulin deficiency and insulin insensitivity are involved in the aetiology of non-insulin-dependent diabetes mellitus (NIDDM), we examined whether patients with NIDDM exhibit genetic variability in the coding region of insulin receptor substrate-1 (IRS-1), a candidate...... with NIDDM and 3 of the controls were heterozygous at codon 972 for a polymorphism in which glycine was substituted with arginine. Moreover, at codon 513, 6 patients with NIDDM and 2 controls had a heterozygous polymorphism with a transition from alanine to proline. None of the polymorphism carriers had both...

  18. Growth orientation dependence of Si doping in GaAsN

    Energy Technology Data Exchange (ETDEWEB)

    Han, Xiuxun, E-mail: xxhan@semi.ac.cn [Laboratory of Clean Energy Chemistry and Materials, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China); State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China); Dong, Chen [Laboratory of Clean Energy Chemistry and Materials, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China); Feng, Qiang [Optoelectronic Department, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033 (China); Ohshita, Yoshio; Yamaguchi, Masafumi [Toyota Technological Institute, 2-12-1 Hisakata, Tempaku, Nagoya, 468-8511 (Japan)

    2015-02-07

    The incorporation of Si in GaAsN alloys grown simultaneously on (100), (311)A, (311)B, and (211)B GaAs substrates by the chemical beam epitaxy has been investigated. The decrease in electron concentration with the increasing N composition suggests the occurrence of N and Si interaction, whereas the interaction exhibits evidently different extent depending on the growth orientation. Combined with the secondary ion mass spectrometry and photoluminescence measurements, it is revealed that (311)B and (211)B are the promising substrate orientations to reduce the N-Si passivation and improve n-type Si doping in GaAsN over a wider N composition range. A surface bonding model is utilized to explain the plane polarity dependent incorporation behaviors of Si and N.

  19. Growth of TiO2 Thin Film on Various Substrates using RF Magnetron Sputtering

    International Nuclear Information System (INIS)

    Ali, Riyaz Ahmad Mohamed; Nayan, Nafarizal

    2011-01-01

    The conductivity of Titanium Dioxide (TiO 2 ) thin film fabricated using Radio Frequency (RF) Magnetron Sputtering on Silicon (Si), Indium doped--Tin Oxide (ITO) and microscope glass (M) substrates is presented in this paper. The dependant of thin film thickness and type of substrate been discussed. TiO 2 was deposited using Ti target in Ar+O 2 (45:10) mixture at 250 W for 45, 60, 75, 90, 105 and 120 minute. Resultant thickness varies from 295 nm to 724 nm with deposition rate 6.4 nm/min. On the other hand, resistivity, Rs value for ITO substrate is between 5.72x10 -7 to 1.54x10 -6 Ω.m, Si substrate range is between 3.52x10 -6 to 1.76x10 -5 Ω.m and M substrate range is between 99 to 332 Ω.m. The value of resistivity increases with the thickness of the thin film.

  20. Growth-rate-dependent dynamics of a bacterial genetic oscillator

    Science.gov (United States)

    Osella, Matteo; Lagomarsino, Marco Cosentino

    2013-01-01

    Gene networks exhibiting oscillatory dynamics are widespread in biology. The minimal regulatory designs giving rise to oscillations have been implemented synthetically and studied by mathematical modeling. However, most of the available analyses generally neglect the coupling of regulatory circuits with the cellular “chassis” in which the circuits are embedded. For example, the intracellular macromolecular composition of fast-growing bacteria changes with growth rate. As a consequence, important parameters of gene expression, such as ribosome concentration or cell volume, are growth-rate dependent, ultimately coupling the dynamics of genetic circuits with cell physiology. This work addresses the effects of growth rate on the dynamics of a paradigmatic example of genetic oscillator, the repressilator. Making use of empirical growth-rate dependencies of parameters in bacteria, we show that the repressilator dynamics can switch between oscillations and convergence to a fixed point depending on the cellular state of growth, and thus on the nutrients it is fed. The physical support of the circuit (type of plasmid or gene positions on the chromosome) also plays an important role in determining the oscillation stability and the growth-rate dependence of period and amplitude. This analysis has potential application in the field of synthetic biology, and suggests that the coupling between endogenous genetic oscillators and cell physiology can have substantial consequences for their functionality.

  1. Multilayer graphene growth on polar dielectric substrates using chemical vapour deposition

    Science.gov (United States)

    Karamat, S.; Çelik, K.; Shah Zaman, S.; Oral, A.

    2018-06-01

    High quality of graphene is necessary for its applications at industrial scale production. The most convenient way is its direct growth on dielectrics which avoid the transfer route of graphene from metal to dielectric substrate usually followed by graphene community. The choice of a suitable dielectric for the gate material which can replace silicon dioxide (SiO2) is in high demand. Various properties like permittivity, thermodynamic stability, film morphology, interface quality, bandgap and band alignment of other dielectrics with graphene needs more exploration. A potential dielectric material is required which could be used to grow graphene with all these qualities. Direct growth of graphene on magnesium oxide (MgO) substrates is an interesting idea and will be a new addition in the library of 2D materials. The present work is about the direct growth of graphene on MgO substrates by an ambient pressure chemical vapour deposition (CVD) method. We address the surface instability issue of the polar oxides which is the most challenging factor in MgO. Atomic force microscopy (AFM) measurements showed the topographical features of the graphene coated on MgO. X-ray photoelectron spectroscopy (XPS) study is carried out to extract information regarding the presence of necessary elements, their bonding with substrates and to confirm the sp-2 hybridization of carbon, which is a characteristic feature of graphene film. The chemical shift is due to the surface reconstruction of MgO in the prepared samples. For graphene-MgO interface, valence band offset (VBO) and conduction band offset (CBO) extracted from valence band spectra reported. Further, we predicted the energy band diagram for single layer and thin film of graphene. By using the room-temperature energy band gap values of MgO and graphene, the CBO is calculated to be 6.85 eV for single layer and 5.66 eV for few layer (1-3) of graphene layers.

  2. Effects of substrate misorientation and growth rate on ordering in GaInP

    Science.gov (United States)

    Su, L. C.; Ho, I. H.; Stringfellow, G. B.

    1994-05-01

    Epitaxial layers of GaxIn1-xP with x≊0.52 have been grown by organometallic vapor-phase epitaxy on GaAs substrates misoriented from the (001) plane in the [1¯10] direction by angles ϑm, of 0°, 3°, 6°, and 9°. For each substrate orientation growth rates rg of 1, 2, and 4 μm/h have been used. The ordering was characterized using transmission electron diffraction (TED), dark-field imaging, and photoluminescence. The (110) cross-sectional images show domains of the Cu-Pt structure separated by antiphase boundaries (APBs). The domain size and shape and the degree of order are found to be strongly affected by both the substrate misorientation and the growth rate. For example, lateral domain dimensions range from 50 Å for layers grown with rg=4 μm/h and ϑm=0° to 2500 Å for rg=1 μm/h and ϑm=9°. The APBs generally propagate from the substrate/epilayer interface to the top surface at an angle to the (001) plane that increases dramatically as the angle of misorientation increases. The angle is nearly independent of growth rate. From the superspot intensities in the TED patterns, the degree of order appears to be a maximum for ϑm≊5°. Judging from the reduction in photoluminescence peak energy caused by ordering, the maximum degree of order appears to occur at ϑm≊4°.

  3. BMP signaling regulates satellite cell-dependent postnatal muscle growth.

    Science.gov (United States)

    Stantzou, Amalia; Schirwis, Elija; Swist, Sandra; Alonso-Martin, Sonia; Polydorou, Ioanna; Zarrouki, Faouzi; Mouisel, Etienne; Beley, Cyriaque; Julien, Anaïs; Le Grand, Fabien; Garcia, Luis; Colnot, Céline; Birchmeier, Carmen; Braun, Thomas; Schuelke, Markus; Relaix, Frédéric; Amthor, Helge

    2017-08-01

    Postnatal growth of skeletal muscle largely depends on the expansion and differentiation of resident stem cells, the so-called satellite cells. Here, we demonstrate that postnatal satellite cells express components of the bone morphogenetic protein (BMP) signaling machinery. Overexpression of noggin in postnatal mice (to antagonize BMP ligands), satellite cell-specific knockout of Alk3 (the gene encoding the BMP transmembrane receptor) or overexpression of inhibitory SMAD6 decreased satellite cell proliferation and accretion during myofiber growth, and ultimately retarded muscle growth. Moreover, reduced BMP signaling diminished the adult satellite cell pool. Abrogation of BMP signaling in satellite cell-derived primary myoblasts strongly diminished cell proliferation and upregulated the expression of cell cycle inhibitors p21 and p57 In conclusion, these results show that BMP signaling defines postnatal muscle development by regulating satellite cell-dependent myofiber growth and the generation of the adult muscle stem cell pool. © 2017. Published by The Company of Biologists Ltd.

  4. Substrate in the emergence and initial growth of seedlings of Caesalpinia pulcherrima

    Directory of Open Access Journals (Sweden)

    Magnólia Martins Alves

    Full Text Available ABSTRACT: Caesalpinia pulcherrima is an exotic species belongs to the Fabaceae family commonly known as flamboyant-mirim, and widely used for urban forestry. This study aimed to evaluate the effect of different substrates on the emergence and early seedlings growth of C. pulcherrima . The experiment was conducted in a greenhouse belonging to the Centro de Ciências Agrárias, Universidade Federal da Paraíba. The experimental design was completely randomized and treatments had 14 substrates: sand, vegetable soil, vermiculite, wood dust, carbonized rice straw, vegetable soil + sand 1:1, sand + wood dust 1:1, sand + carbonized rice straw 1:1, earth + wood dust 1:1, vegetable soil + carbonized rice straw 1:1, vermiculite + sand 1:1, vermiculite + wood dust 1:1, vermiculite + earth 1:1 and vermiculite + carbonized rice straw 1:1. Evaluation of the effect of the treatments was through the following determinations: percentage of emergency, first count, index of germination speed, length and dry weight of roots and shoots. The vermiculite, vegetable soil + sand 1:1, vermiculite + sand 1:1, vermiculite + saw dust 1:1, are suitable for emergence and early growth of seedlings of Caesalpinia pulcherrima . Substrates saw dust and carbonized rice straw were responsible for the worst performers on emergence and seedling development.

  5. Growth and yield performance of Pleurotus ostreatus (Jacq. Fr.) Kumm (oyster mushroom) on different substrates.

    Science.gov (United States)

    Girmay, Zenebe; Gorems, Weldesemayat; Birhanu, Getachew; Zewdie, Solomon

    2016-12-01

    Mushroom cultivation is reported as an economically viable bio-technology process for conversion of various lignocellulosic wastes. Given the lack of technology know-how on the cultivation of mushroom, this study was conducted in Wondo Genet College of Forestry and Natural Resource, with the aim to assess the suitability of selected substrates (agricultural and/or forest wastes) for oyster mushroom cultivation. Accordingly, four substrates (cotton seed, paper waste, wheat straw, and sawdust) were tested for their efficacy in oyster mushroom production. Pure culture of oyster mushroom was obtained from Mycology laboratory, Department of Plant Biology and Biodiversity Management, Addis Ababa University. The pure culture was inoculated on potato dextrose agar for spawn preparation. Then, the spawn containing sorghum was inoculated with the fungal culture for the formation of fruiting bodies on the agricultural wastes. The oyster mushroom cultivation was undertaken under aseptic conditions, and the growth and development of mushroom were monitored daily. Results of the study revealed that oyster mushroom can grow on cotton seed, paper waste, sawdust and wheat straw, with varying growth performances. The highest biological and economic yield, as well as the highest percentage of biological efficiency of oyster mushroom was obtained from cotton seed, while the least was from sawdust. The study recommends cotton seed, followed by paper waste as suitable substrates for the cultivation of oyster mushroom. It also suggests that there is a need for further investigation on various aspects of oyster mushroom cultivation in Ethiopia to promote the industry.

  6. Halo(natronoarchaea isolated from hypersaline lakes utilize cellulose and chitin as growth substrates

    Directory of Open Access Journals (Sweden)

    Dimitry Y Sorokin

    2015-09-01

    Full Text Available Until recently, extremely halophilic euryarchaeota were considered mostly as aerobic heterotrophs utilizing simple organic compounds as growth substrates. Almost nothing is known on the ability of these prokaryotes to utilize complex polysaccharides as cellulose, xylan and chitin. Although few haloarchaeal cellulases and chitinases were recently characterized, the analysis of currently available haloarchaeal genomes deciphered numerous genes encoding glycosidases (GHs of various families including endoglucanases and chitinases. However, all these haloarchaea were isolated and cultivated on simple substrates and their ability to grow on polysaccharides in situ or in vitro is unknown. This study examines several halo(natronoarchaeal strains from geographically distant hypersaline lakes for the ability to grow on insoluble polymers as a sole growth substrate in salt-saturated mineral media. Some of them belonged to known taxa, while other represented novel phylogenetic lineages within the class Halobacteria. All isolates produced extracellular extremely salt tolerant cellulases or chitinases, either cell-free or cell-bound. Obtained results demonstrate a presence of diverse population of haloarchaeal cellulo/chitinotrophs in hypersaline habitats indicating that euryarchaea participate in aerobic mineralization of recalcitrant organic polymers in salt-saturated environments.

  7. Growth-substrate induced performance degradation in chemically synthesized monolayer MoS{sub 2} field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Amani, Matin; Chin, Matthew L.; Mazzoni, Alexander L.; Burke, Robert A.; Dubey, Madan, E-mail: madan.dubey.civ@mail.mil [Sensors and Electron Devices Directorate, US Army Research Laboratory, Adelphi, Maryland 20723 (United States); Najmaei, Sina; Ajayan, Pulickel M.; Lou, Jun [Department of Materials Science and Nanoengineering, Rice University, Houston, Texas 77005 (United States)

    2014-05-19

    We report on the electronic transport properties of single-layer thick chemical vapor deposition (CVD) grown molybdenum disulfide (MoS{sub 2}) field-effect transistors (FETs) on Si/SiO{sub 2} substrates. MoS{sub 2} has been extensively investigated for the past two years as a potential semiconductor analogue to graphene. To date, MoS{sub 2} samples prepared via mechanical exfoliation have demonstrated field-effect mobility values which are significantly higher than that of CVD-grown MoS{sub 2}. In this study, we will show that the intrinsic electronic performance of CVD-grown MoS{sub 2} is equal or superior to that of exfoliated material and has been possibly masked by a combination of interfacial contamination on the growth substrate and residual tensile strain resulting from the high-temperature growth process. We are able to quantify this strain in the as-grown material using pre- and post-transfer metrology and microscopy of the same crystals. Moreover, temperature-dependent electrical measurements made on as-grown and transferred MoS{sub 2} devices following an identical fabrication process demonstrate the improvement in field-effect mobility.

  8. Effects of substrate type on growth and mortality of blue mussels ( Mytilus edulis ) exposed to the predator Carcinus maenas

    DEFF Research Database (Denmark)

    Frandsen, Rikke; Dolmer, Per

    2002-01-01

    Structure and complexity of the substrate are important habitat characteristics for benthic epifauna. The specific growth and mortality rates and inducible defence characters on medium- sized blue mussels (Mytilus edulis L.) exposed to shore crabs (Carcinus maenas L.) were examined on three...... different substrate types in combined field and laboratory experiments. The experiments showed that complexity of the substrate increased blue mussel survival significantly, through a decrease in predation pressure. However, increased intraspecific competition for food on the complex substrate resulted...... in significantly lower growth rates of the mussels. Inducible defence characters were also influenced by substrate type. Blue mussels were more affected by predators on the structurally simple substrate, where they developed thicker shells and a larger posterior adductor muscle....

  9. Dual inoculation with an Aarbuscular Mycorrhizal fungus and Rhizobium to facilitate the growth of alfalfa on coal mine substrates

    Energy Technology Data Exchange (ETDEWEB)

    Wu, F.Y.; Bi, Y.L.; Wong, M.H. [China University of Mining & Technology, Beijing (China)

    2009-07-01

    A pot experiment was conducted to investigate the effects of Glomus mosseae and Rhizobium on Medicago sativa grown on three types of coal mine substrates, namely a mixture of coal wastes and sands (CS), coal wastes and fly ash (CF), and fly ash (FA). Inoculation with Rhizobium alone did not result in any growth response but G. mosseae alone displayed a significant effect on plant growth. G. mosseae markedly increased the survival rate of M. sativa in CS substrate. In CF and FA substrates the respective oven dry weights of M. sativa inoculated with G. mosseae were 1.8 and 5.1 times higher than those without inoculation. Based on nitrogen (N), phosphorus (P) and potassium (K) uptake and legume growth, the results also show that dual inoculation in CS and CF substrates elicited a synergistic effect. This indicates that inoculation with arbuscular mycorrhizal (AM) fungi may be a promising approach for revegetation of coal mine substrates.

  10. Substrate-dependent inhibition of human MATE1 by cationic ionic liquids.

    Science.gov (United States)

    Martínez-Guerrero, Lucy J; Wright, Stephen H

    2013-09-01

    The multidrug and toxin extruders 1- and 2-K (MATE1 and MATE2-K) are expressed in the luminal membrane of renal proximal tubule cells and provide the active step in the secretion of molecules that carry a net positive charge at physiologic pH, so-called organic cations. The present study tested whether structurally distinct MATE substrates can display different quantitative profiles of inhibition when interacting with structurally distinct ligands. The tested ligands were three structurally similar cationic ionic liquids (ILs, salts in the liquid state: N-butylpyridinium, NBuPy; 1-methyl-3-butylimidazolium, Bmim; and N-butyl-N-methylpyrrolidinium, BmPy). Uptake was measured using Chinese hamster ovary cells that stably expressed MATE1 or MATE2-K. By trans-stimulation, all three ILs were transported by both MATE transporters. The three ILs also inhibited uptake of three structurally distinct MATE substrates: 1-methyl-4-phenylpyridinium (MPP), triethylmethylammonium (TEMA), and N,N,N-trimethyl-2-[methyl(7-nitrobenzo[c][1,2,5]oxadiazol-4-yl)amino]ethanaminium (NBD-MTMA). MATE1 displayed a higher affinity for the pyridinium-based NBuPy (IC50 values, 2-4 µM) than for either the pyrrolidinium- (BmPy; 20-70 µM) or imidazolium-based ILs (Bmim; 15-60 µM). Inhibition of MPP, TEMA, and NBD-MTMA transport by NBuPy was competitive, with comparable Ki values against all substrates. Bmim also competitively blocked the three substrates but with Ki values that differed significantly (20 µM against MPP and 30 µM against NBD-MTMA versus 60 µM against TEMA). Together, these data indicate that renal secretion of ILs by the human kidney involves MATE transporters and suggest that the mechanism of transport inhibition is ligand-dependent, supporting the hypothesis that the binding of substrates to MATE transporters involves interaction with a binding surface with multiple binding sites.

  11. Differential subcellular localization of insulin receptor substrates depends on C-terminal regions and importin β

    International Nuclear Information System (INIS)

    Kabuta, Tomohiro; Take, Kazumi; Kabuta, Chihana; Hakuno, Fumihiko; Takahashi, Shin-Ichiro

    2008-01-01

    Insulin receptor substrates (IRSs) play essential roles in signal transduction of insulin and insulin-like growth factors. Previously, we showed that IRS-3 is localized to the nucleus as well as the cytosol, while IRS-1 and 2 are mainly localized to the cytoplasm. In the present study, we found that importin β directly interacts with IRS-3 and is able to mediate nuclear transport of IRS-3. Importin β interacted with the pleckstrin homology domain, the phosphotyrosine binding domain and the C-terminal region of IRS-3; indeed all of these fragments exhibited predominant nuclear localization. By contrast, almost no interaction of importin β with IRS-1 and -2 was observed, and their C-terminal regions displayed discrete spotty images in the cytosol. In addition, using chimeric proteins between IRS-1 and IRS-3, we revealed that the C-terminal regions are the main determinants of the differing subcellular localizations of IRS-1 and IRS-3.

  12. Room temperature growth of biaxially aligned yttria-stabilized zirconia films on glass substrates by pulsed-laser deposition

    CERN Document Server

    Li Peng; Mazumder, J

    2003-01-01

    Room temperature deposition of biaxially textured yttria-stabilized zirconia (YSZ) films on amorphous glass substrates was successfully achieved by conventional pulsed-laser deposition. The influence of the surrounding gases, their pressure and the deposition time on the structure of the films was studied. A columnar growth process was revealed based on the experimental results. The grown biaxial texture appears as a kind of substrate independence, which makes it possible to fabricate in-plane aligned YSZ films on various substrates.

  13. Substrate and growth related microstructural and magnetic properties in La{sub 0.67}Sr{sub 0.33}MnO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Hawley, M.E.; Brown, G.W.; Kwon, C.; Jia, Q.

    1998-12-31

    Ambient observation of magnetic domain structures by magnetic force microscopy (MFM) in La{sub 0.67}Sr{sub 0.33}MnO{sub 3} films has not yet been clearly correlated with stresses induced by kinetic or thermodynamic growth processes or the compressive (LaAlO{sub 3}) or tensile (SrTiO{sub 3}) nature of the film-substrate lattice mismatch. Although domain-like magnetic structures have been seen in some as-grown films and related to substrate-induced stress and film thickness, no magnetic structure has been seen for other films grown under similar conditions on the same pair of substrates. In this study the authors have grown films over a range of temperatures by pulsed-laser deposition, using the above substrates, to determine the relationship between growth and stress-induced magnetic structures. Results from scanning tunneling, atomic force, and magnetic force microscopies, measurements of temperature-dependent magnetization and structure-dependent coercivity show the relationship between growth and magnetic properties. Maze-like domain structures, with separations between 150 nm and 200 nm, were only observed for the thicker films grown at the highest temperature, 800 C. Application of an in-plane magnetic field converted these domain structures to stripe-like domains whose spacing and out of plane component decreased as the field was increased.

  14. Influence of electron beam irradiation on growth of Phytophthora cinnamomi and its control in substrates

    Science.gov (United States)

    MigdaŁ, Wojciech; Orlikowski, Leszek B.; Ptaszek, Magdalena; Gryczka, Urszula

    2012-08-01

    Very extensive production procedure, especially in plants growing under covering, require methods, which would allow quick elimination or substantial reduction of populations of specific pathogens without affecting the growth and development of the cultivated plants. Among soil-borne pathogens, the Phytophthora species are especially dangerous for horticultural plants. In this study, irradiation with electron beam was applied to control Phytophthora cinnamomi. The influence of irradiation dose on the reduction of in vitro growth and the population density of the pathogen in treated peat and its mixture with composted pine bark (1:1), as well as the health of Chamaecyparis lawsoniana and Lavandula angustifolia plants were evaluated. Application of irradiation at a dose of 1.5 kGy completely inhibited the in vitro development of P. cinnamomi. This irradiation effect was connected with the disintegration of the hyphae and spores of the species. Irradiation of peat and its mixture with composted pine bark with 10 kGy resulted in the inhibition of stem base rot development in Ch. lawsoniana. Symptoms of the disease were not observed when the substrates were treated with 15 kGy. In the case of L. angustifolia, stem root rot was not observed on cuttings transplanted to infected peat irradiated at a dose of 10 kGy. Irradiation of the horticultural substrates did not affect plant growth.

  15. Poinsettia Growth and Development Response to Container Root Substrate with Biochar

    Directory of Open Access Journals (Sweden)

    Yanjun Guo

    2018-01-01

    Full Text Available A greenhouse study was conducted to evaluate the growth and development of poinsettia ‘Prestige Red’ (Euphorbia pulcherrima grown in a commercial peat-based potting mix (Sunshine Mix #1 amended with biochar at 0%, 20%, 40%, 60%, 80%, or 100% (by volume at four different fertigation regimes: F1: 100 to 200 mg·L−1 nitrogen (N, F2: 200 to 300 mg·L−1 N (control, F3: 300 to 400 mg·L−1 N, or F4: 400 to 500 mg·L−1 N. The experiment was a two-factor factorial design with 10 replications for each combination of biochar by fertigation. As the percentage of biochar increased, root substrate pore space and bulk density increased, while container capacity decreased. Root rot and red bract necrosis only occurred in F4 combined with 100% biochar. Plants grown in 40% biochar had a similar growth and development to those in 0% biochar. Up to 80% biochar, plants exhibited no significant change, except in terms of dry weight, which decreased at higher biochar percentages (60% and 80%. In summary, at a fertigation rate of 100 mg·L−1 N to 400 mg·L−1 N, up to 80% biochar could be used as an amendment to peat-based root substrate with acceptable growth reduction and no changes in quality.

  16. Redox-dependent substrate-cofactor interactions in the Michaelis-complex of a flavin-dependent oxidoreductase

    Science.gov (United States)

    Werther, Tobias; Wahlefeld, Stefan; Salewski, Johannes; Kuhlmann, Uwe; Zebger, Ingo; Hildebrandt, Peter; Dobbek, Holger

    2017-07-01

    How an enzyme activates its substrate for turnover is fundamental for catalysis but incompletely understood on a structural level. With redox enzymes one typically analyses structures of enzyme-substrate complexes in the unreactive oxidation state of the cofactor, assuming that the interaction between enzyme and substrate is independent of the cofactors oxidation state. Here, we investigate the Michaelis complex of the flavoenzyme xenobiotic reductase A with the reactive reduced cofactor bound to its substrates by X-ray crystallography and resonance Raman spectroscopy and compare it to the non-reactive oxidized Michaelis complex mimics. We find that substrates bind in different orientations to the oxidized and reduced flavin, in both cases flattening its structure. But only authentic Michaelis complexes display an unexpected rich vibrational band pattern uncovering a strong donor-acceptor complex between reduced flavin and substrate. This interaction likely activates the catalytic ground state of the reduced flavin, accelerating the reaction within a compressed cofactor-substrate complex.

  17. Strain- and Substrate-Dependent Redox Mediator and Electricity Production by Pseudomonas aeruginosa.

    Science.gov (United States)

    Bosire, Erick M; Blank, Lars M; Rosenbaum, Miriam A

    2016-08-15

    Pseudomonas aeruginosa is an important, thriving member of microbial communities of microbial bioelectrochemical systems (BES) through the production of versatile phenazine redox mediators. Pure culture experiments with a model strain revealed synergistic interactions of P. aeruginosa with fermenting microorganisms whereby the synergism was mediated through the shared fermentation product 2,3-butanediol. Our work here shows that the behavior and efficiency of P. aeruginosa in mediated current production is strongly dependent on the strain of P. aeruginosa We compared levels of phenazine production by the previously investigated model strain P. aeruginosa PA14, the alternative model strain P. aeruginosa PAO1, and the BES isolate Pseudomonas sp. strain KRP1 with glucose and the fermentation products 2,3-butanediol and ethanol as carbon substrates. We found significant differences in substrate-dependent phenazine production and resulting anodic current generation for the three strains, with the BES isolate KRP1 being overall the best current producer and showing the highest electrochemical activity with glucose as a substrate (19 μA cm(-2) with ∼150 μg ml(-1) phenazine carboxylic acid as a redox mediator). Surprisingly, P. aeruginosa PAO1 showed very low phenazine production and electrochemical activity under all tested conditions. Microbial fuel cells and other microbial bioelectrochemical systems hold great promise for environmental technologies such as wastewater treatment and bioremediation. While there is much emphasis on the development of materials and devices to realize such systems, the investigation and a deeper understanding of the underlying microbiology and ecology are lagging behind. Physiological investigations focus on microorganisms exhibiting direct electron transfer in pure culture systems. Meanwhile, mediated electron transfer with natural redox compounds produced by, for example, Pseudomonas aeruginosa might enable an entire microbial

  18. Molecular mechanism of pH-dependent substrate transport by an arginine-agmatine antiporter.

    Science.gov (United States)

    Wang, Sheng; Yan, Renhong; Zhang, Xi; Chu, Qi; Shi, Yigong

    2014-09-02

    Enteropathogenic bacteria, exemplified by Escherichia coli, rely on acid-resistance systems (ARs) to survive the acidic environment of the stomach. AR3 consumes intracellular protons through decarboxylation of arginine (Arg) in the cytoplasm and exchange of the reaction product agmatine (Agm) with extracellular Arg. The latter process is mediated by the Arg:Agm antiporter AdiC, which is activated in response to acidic pH and remains fully active at pH 6.0 and below. Despite our knowledge of structural information, the molecular mechanism by which AdiC senses acidic pH remains completely unknown. Relying on alanine-scanning mutagenesis and an in vitro proteoliposome-based transport assay, we have identified Tyr74 as a critical pH sensor in AdiC. The AdiC variant Y74A exhibited robust transport activity at all pH values examined while maintaining stringent substrate specificity for Arg:Agm. Replacement of Tyr74 by Phe, but not by any other amino acid, led to the maintenance of pH-dependent substrate transport. These observations, in conjunction with structural information, identify a working model for pH-induced activation of AdiC in which a closed conformation is disrupted by cation-π interactions between proton and the aromatic side chain of Tyr74.

  19. pH and generation dependent morphologies of PAMAM dendrimers on a graphene substrate.

    Science.gov (United States)

    Gosika, Mounika; Maiti, Prabal K

    2018-03-07

    The adsorption of PAMAM dendrimers at solid/water interfaces has been extensively studied, and is mainly driven by electrostatic and van der Waals interactions between the substrate and the dendrimers. However, the pH dependence of the adsorption driven predominantly by the van der Waals interactions is poorly explored, although it is crucial for investigating the potentiality of these dendrimers in supercapacitors and surface patterning. Motivated by this aspect, we have studied the adsorption behavior of PAMAM dendrimers of generations 2 (G2) to 5 (G5) with pH and salt concentration variation, on a charge neutral graphene substrate, using fully atomistic molecular dynamics simulations. The instantaneous snapshots from our simulations illustrate that the dendrimers deform significantly from their bulk structures. Based on various structural property calculations, we classify the adsorbed dendrimer morphologies into five categories and map them to a phase diagram. Interestingly, the morphologies we report here have striking analogies with those reported in star-polymer adsorption studies. From the fractional contacts and other structural property analyses we find that the deformations are more pronounced at neutral pH as compared to high and low pH. Higher generation dendrimers resist deformation following the deformation trend, G2 > G3 > G4 > G5 at any given pH level. As the adsorption here is mainly driven by van der Waals interactions, we observe no desorption of the dendrimers as the salt molarity is increased, unlike that reported in the electrostatically driven adsorption studies.

  20. Growth of InAs/InGaAs nanowires on GaAs(111)B substrates

    Energy Technology Data Exchange (ETDEWEB)

    Scholz, Sven; Schott, Ruediger; Ludwig, Arne; Wieck, Andreas D. [Lehrstuhl fuer Angewandte Festkoerperphysik, Ruhr-Universitaet Bochum (Germany); Reuter, Dirk [Arbeitsgruppe fuer optoelektronische Materialien und Bauelemente, Universitaet Paderborn (Germany)

    2013-07-01

    To investigate the structure and behavior of individual 1D-quantum structures, so called nanowires, we have grown single localized Au seeded InAs/InGaAs nanowires on GaAs(111)B substrate by molecular beam epitaxy. The Au-seeds are implanted by focused ion beam (FIB) technology. We developed a AuGa-LMIS to avoid the beam spread induced by using a Wien-Filter, which allows us to reduce the spot size of the focused ion beam and as consequence the number of implanted ions necessary to seed a wire. At present the growth of InAs nanowires is not fully understood and we have been working on optimizing the process. We identified an optimal growth temperature and arsenic to indium ratio for nanowire growth. Further investigations also aim at analyzing the influence of the growth rates and growth directions. We studied the morphology of the nanowires by SEM imaging and the optical properties with photoluminescence spectroscopy.

  1. Stabilisation of spent mushroom substrate for application as a plant growth-promoting organic amendment.

    Science.gov (United States)

    Paula, Fabiana S; Tatti, Enrico; Abram, Florence; Wilson, Jude; O'Flaherty, Vincent

    2017-07-01

    Over three million tonnes of spent mushroom substrate (SMS) are produced in Europe every year as a by-product of the cultivation of Agaricus bisporus. The management of SMS has become an increasing challenge for the mushroom production industry, and finding environmentally and economically sustainable solutions for this organic residue is, therefore, highly desirable. Due to its physical properties and nutrient content, SMS has great potential to be employed in agricultural and horticultural sectors, and further contribute to reduce the use of non-renewable resources, such as peat. However, SMS is often regarded as not being stable and/or mature, which hampers its wide use for crop production. Here, we demonstrate the stabilisation of SMS and its subsequent use as organic fertiliser and partial peat replacement in horticulture. The stabilisation was performed in a laboratory-scale composting system, with controlled temperature and aeration. Physical and chemical parameters were monitored during composting and provided information on the progress of the process. Water soluble carbohydrates (WSC) content was found to be the most reliable parameter to predict SMS stability. In situ oxygen consumption indicated the main composting phases, reflecting major changes in microbial activity. The structure of the bacterial community was also found to be a potential predictor of stability, as the compositional changes followed the composting progress. By contrast, the fungal community did not present clear successional process along the experiment. Maturity and quality of the stabilised SMS were assessed in a horticultural growing trial. When used as the sole fertiliser source, SMS was able to support Lolium multiflorum (Italian ryegrass) growth and significantly improved grass yield with a concentration-dependent response, increasing grass biomass up to 300%, when compared to the untreated control. In summary, the results indicated that the method employed was efficient in

  2. Nucleation and Growth of GaN on GaAs (001) Substrates

    International Nuclear Information System (INIS)

    Drummond, Timothy J.; Hafich, Michael J.; Heller, Edwin J.; Lee, Stephen R.; Liliental-Weber, Zuzanna; Ruvimov, Sergei; Sullivan, John P.

    1999-01-01

    The nucleation of GaN thin films on GaAs is investigated for growth at 620 ''C. An rf plasma cell is used to generate chemically active nitrogen from N 2 . An arsenic flux is used in the first eight monolayer of nitride growth to enhance nucleation of the cubic phase. Subsequent growth does not require an As flux to preserve the cubic phase. The nucleation of smooth interfaces and GaN films with low stacking fault densities is dependent upon relative concentrations of active nitrogen species in the plasma and on the nitrogen to gallium flux ratio

  3. Nucleation and growth microstructural study of ti films on 304 SS substrates

    Directory of Open Access Journals (Sweden)

    Rogério de Almeida Vieira

    2004-09-01

    Full Text Available Coating of steel surfaces with titanium films has been studied with the objective to protect them against corrosion, and to create an intermediate film for CVD diamond and TiN film deposition. In this work, the nucleation, growth mechanisms and microstructural formation of the titanium films deposited on 304 stainless steel (304 SS substrate are presented and discussed. The titanium films of variable thickness were obtained by vapour phase deposition produced by electron beam. The surfaces of these samples were observed by scanning electron microscopy. The cross sections of these samples were observed by using an atomic force microscope. The Ti film-304 SS interfaces were analyzed by X-ray diffraction. The results showed that titanium films have a columnar growth. The Ti film-304 SS interface had a residual compression stress at room temperature due to the inter-diffusion process.

  4. Low temperature metal free growth of graphene on insulating substrates by plasma assisted chemical vapor deposition

    Science.gov (United States)

    Muñoz, R.; Munuera, C.; Martínez, J. I.; Azpeitia, J.; Gómez-Aleixandre, C.; García-Hernández, M.

    2017-03-01

    Direct growth of graphene films on dielectric substrates (quartz and silica) is reported, by means of remote electron cyclotron resonance plasma assisted chemical vapor deposition r-(ECR-CVD) at low temperature (650 °C). Using a two step deposition process- nucleation and growth- by changing the partial pressure of the gas precursors at constant temperature, mostly monolayer continuous films, with grain sizes up to 500 nm are grown, exhibiting transmittance larger than 92% and sheet resistance as low as 900 Ω sq-1. The grain size and nucleation density of the resulting graphene sheets can be controlled varying the deposition time and pressure. In additon, first-principles DFT-based calculations have been carried out in order to rationalize the oxygen reduction in the quartz surface experimentally observed. This method is easily scalable and avoids damaging and expensive transfer steps of graphene films, improving compatibility with current fabrication technologies.

  5. Plantago lanceolata growth and Cr uptake after mycorrhizal inoculation in a Cr amended substrate

    Directory of Open Access Journals (Sweden)

    Amaia Nogales

    2012-03-01

    Full Text Available Arbuscular mycorrhizal fungi from two chromium contaminated sites, one with 275 mg kg-1 of Cr (zone A and the other with 550 mg kg-1 Cr (zone B, were multiplied and tentatively identified. The effect of both fungal consortia on Plantago lanceolata plant growth in a substrate amended with 200 mg kg-1 of Cr and with 400 mg kg-1 Cr was assessed and compared with the growth of plants inoculated with Glomus intraradices BEG72. Only the plants inoculated with G. intraradices BEG72 and with the fungal consortia obtained from the area with a high Cr contamination (zone B grew in the soil with 400 mg kg-1 of Cr. The consortia of fungi from zone B, decreased the plant’s uptake/translocation of the heavy metal compared with G. intraradices BEG72. These results underscore the differential effect of AM fungi in conferring bioprotection in Cr contaminated soils.

  6. Growth and characterization of straight InAs/GaAs nanowire heterostructures on Si substrate

    International Nuclear Information System (INIS)

    Yan Xin; Zhang Xia; Li Jun-Shuai; Lü Xiao-Long; Ren Xiao-Min; Huang Yong-Qing

    2013-01-01

    Vertical InAs/GaAs nanowire (NW) heterostructures with a straight InAs segment have been successfully fabricated on Si (111) substrate by using AlGaAs/GaAs buffer layers coupled with a composition grading InGaAs segment. Both the GaAs and InAs segments are not limited by the misfit strain induced critical diameter. The low growth rate of InAs NWs is attributed to the AlGaAs/GaAs buffer layers which dramatically decrease the adatom diffusion contribution to the InAs NW growth. The crystal structure of InAs NW can be tuned from zincblende to wurtzite by controlling its diameter as well as the length of GaAs NWs. This work helps to open up a road for the integration of high-quality III-V NW heterostructures with Si

  7. Effects of Precursor-Substrate Distances on the Growth of GaN Nanowires

    Directory of Open Access Journals (Sweden)

    Hongbin Cheng

    2015-01-01

    Full Text Available GaN nanowires were synthesized through the Ni-catalyzed chemical vapor deposition (CVD method using Ga2O3/GaN mixtures as gallium sources, and precursor-substrate distances were investigated as the important factor for the growth of GaN nanowires. The microstructure, composition, and photoluminescence property were characterized by X-ray diffraction, field emission scanning electron microscopy, high-resolution transmission electron microscopy, and photoluminescence spectra. The results showed that single crystalline GaN nanowires with the diameter of about 90 nm and the length up to tens of micrometers had been grown thickly across Si (100 substrates with uniform density. Moreover, the variations of the GaN nanowire morphology, density, and size were largely attributed to substrate positions which would influence Ga precursor density in the carrier gas, the saturation degree of gaseous reactants, and the catalyst activity, respectively, in the fabrication of GaN nanowires by the vapour liquid solid mechanism.

  8. History-dependent excitability as a single-cell substrate of transient memory for information discrimination.

    Directory of Open Access Journals (Sweden)

    Fabiano Baroni

    Full Text Available Neurons react differently to incoming stimuli depending upon their previous history of stimulation. This property can be considered as a single-cell substrate for transient memory, or context-dependent information processing: depending upon the current context that the neuron "sees" through the subset of the network impinging on it in the immediate past, the same synaptic event can evoke a postsynaptic spike or just a subthreshold depolarization. We propose a formal definition of History-Dependent Excitability (HDE as a measure of the propensity to firing in any moment in time, linking the subthreshold history-dependent dynamics with spike generation. This definition allows the quantitative assessment of the intrinsic memory for different single-neuron dynamics and input statistics. We illustrate the concept of HDE by considering two general dynamical mechanisms: the passive behavior of an Integrate and Fire (IF neuron, and the inductive behavior of a Generalized Integrate and Fire (GIF neuron with subthreshold damped oscillations. This framework allows us to characterize the sensitivity of different model neurons to the detailed temporal structure of incoming stimuli. While a neuron with intrinsic oscillations discriminates equally well between input trains with the same or different frequency, a passive neuron discriminates better between inputs with different frequencies. This suggests that passive neurons are better suited to rate-based computation, while neurons with subthreshold oscillations are advantageous in a temporal coding scheme. We also address the influence of intrinsic properties in single-cell processing as a function of input statistics, and show that intrinsic oscillations enhance discrimination sensitivity at high input rates. Finally, we discuss how the recognition of these cell-specific discrimination properties might further our understanding of neuronal network computations and their relationships to the distribution and

  9. Influence of electron beam irradiation on growth of Phytophthora cinnamomi and its control in substrates

    International Nuclear Information System (INIS)

    MigdaŁ, Wojciech; Orlikowski, Leszek B.; Ptaszek, Magdalena; Gryczka, Urszula

    2012-01-01

    Very extensive production procedure, especially in plants growing under covering, require methods, which would allow quick elimination or substantial reduction of populations of specific pathogens without affecting the growth and development of the cultivated plants. Among soil-borne pathogens, the Phytophthora species are especially dangerous for horticultural plants. In this study, irradiation with electron beam was applied to control Phytophthora cinnamomi. The influence of irradiation dose on the reduction of in vitro growth and the population density of the pathogen in treated peat and its mixture with composted pine bark (1:1), as well as the health of Chamaecyparis lawsoniana and Lavandula angustifolia plants were evaluated. Application of irradiation at a dose of 1.5 kGy completely inhibited the in vitro development of P. cinnamomi. This irradiation effect was connected with the disintegration of the hyphae and spores of the species. Irradiation of peat and its mixture with composted pine bark with 10 kGy resulted in the inhibition of stem base rot development in Ch. lawsoniana. Symptoms of the disease were not observed when the substrates were treated with 15 kGy. In the case of L. angustifolia, stem root rot was not observed on cuttings transplanted to infected peat irradiated at a dose of 10 kGy. Irradiation of the horticultural substrates did not affect plant growth. - Highlights: ► Electron beam irradiation is effective against soil-borne pathogens. ► Application of irradiation at dose 1.5 kGy completely inhibited in vitro development of Phytophthora cinnamomi. ► Irradiation of horticultural substrata did not influence the growth of plants.

  10. Growth specificity of vertical ZnO nanorods on patterned seeded substrates through integrated chemical process

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, P. Suresh [Thin Film and Nanomaterials Laboratory, Department of Physics, Bharathiar University, Coimbatore 641 046 (India); Maniam, S.M. [Centre for Quantum Technologies, National University of Singapore (Singapore); Sundaramurthy, J. [Department of Chemical and Biomolecular Engineering, National University of Singapore (NUS) (Singapore); Arokiaraj, J. [3M R and D Center (Singapore); Mangalaraj, D., E-mail: dmraj800@yahoo.com [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641046 (India); Rajarathnam, D. [CERAR, University of South Australia, Mawson Lakes, SA-5095 (Australia); Srinivasan, M.P. [Department of Chemical and Biomolecular Engineering, National University of Singapore (NUS) (Singapore); Jian, L.K. [Singapore Synchrotron Light Source (SSLS), National University of Singapore (NUS) (Singapore)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Simple integrated chemical process was adopted for specific ZnO nanorod growth. Black-Right-Pointing-Pointer Size and orientation of nanorods are well controlled by optimum reaction time and temperature. Black-Right-Pointing-Pointer Different site-selective ZnO nanorod growths are demonstrated. - Abstract: A simple and cost effective method has been employed for the random growth and oriented ZnO nanorod arrays over as-prepared and patterned seeded glass substrates by low temperature two step growth process and growth specificity by direct laser writing (DLW) process. Scanning electron microscopy (SEM) images and X-ray diffraction analysis confirm the growth of vertical ZnO nanorods with perfect (0 0 2) orientation along c-axis which is in conjunction with optimizing the parameters at different reaction times and temperatures. Transmission electron microscopy (TEM) images show the formation of vertical ZnO nanorods with diameter and length of {approx}120 nm and {approx}400 nm respectively. Photoluminescence (PL) spectroscopic studies show a narrow emission at {approx}385 nm and a broad visible emission from 450 to 600 nm. Further, site-selective ZnO nanorod growth is demonstrated for its high degree of control over size, orientation, uniformity, and periodicity on a positive photoresist ZnO seed layer by simple geometrical (line, circle and ring) patterns of 10 {mu}m and 5 {mu}m dimensions. The demonstrated control over size, orientation and periodicity of ZnO nanorods process opens up an opportunity to develop multifunctional properties which promises their potential applications in sensor, piezoelectric, and optoelectronic devices.

  11. Catalytic growth of carbon nanowires on composite diamond/silicon substrates

    Energy Technology Data Exchange (ETDEWEB)

    Sellam, Amine [Université de Lorraine, Institut Jean Lamour, Département CP2S (UMR CNRS 7198), Parc de Saurupt, F-54042 Nancy Cedex (France); Miska, Patrice [Université de Lorraine, Institut Jean Lamour, Département P2M (UMR CNRS 7198), Parc de Saurupt, F-54042 Nancy Cedex (France); Ghanbaja, Jaafar [Université de Lorraine, Institut Jean Lamour, Département CP2S (UMR CNRS 7198), Parc de Saurupt, F-54042 Nancy Cedex (France); Barrat, Silvère, E-mail: Silvere.Barrat@ijl.nancy-universite.fr [Université de Lorraine, Institut Jean Lamour, Département CP2S (UMR CNRS 7198), Parc de Saurupt, F-54042 Nancy Cedex (France)

    2014-01-01

    Polycrystalline diamond (PCD) films and carbon nanowires (CNWs) provide individually highly attractive properties for science and technology applications. The possibility of carbon composite materials made from a combination of these materials remains a potential approach widely discussed in literature but modestly investigated. We report in this work an early attempt to explore this opportunity in the light of some specific experimental considerations. Carbon nanowires (CNWs) are grown at low temperature without the conventional use of external hydrocarbon vapor source on silicon substrates partially covered by a thin film of coalesced micrometric CVD diamond. Composite substrates constituted by PCD on silicon were first cleaned with H{sub 2} plasma then used for the PVD deposition of 5 nm Ni thin films. Then, samples were heat treated in a CVD reactor at 580 °C in the presence of pure H{sub 2} pressure of 60 hPa at different annealing times. Comparative effect of annealing time on the dewetting of Ni thin films and the subsequent CNWs growth process was considered in this work using systematic observations by SEM. Possible mechanisms underlying CNWs growth in pure H{sub 2} gas were proposed. The nature and structure of these CNWs have been investigated by TEM microscopy and by Raman spectroscopy on the sample showing the highest CNWs density.

  12. Multiple growths of epitaxial lift-off solar cells from a single InP substrate

    International Nuclear Information System (INIS)

    Lee, Kyusang; Shiu, Kuen-Ting; Zimmerman, Jeramy D.; Forrest, Stephen R.; Renshaw, Christopher K.

    2010-01-01

    We demonstrate multiple growths of flexible, thin-film indium tin oxide-InP Schottky-barrier solar cells on a single InP wafer via epitaxial lift-off (ELO). Layers that protect the InP parent wafer surface during the ELO process are subsequently removed by selective wet-chemical etching, with the active solar cell layers transferred to a thin, flexible plastic host substrate by cold welding at room temperature. The first- and second-growth solar cells exhibit no performance degradation under simulated Atmospheric Mass 1.5 Global (AM 1.5G) illumination, and have a power conversion efficiency of η p =14.4±0.4% and η p =14.8±0.2%, respectively. The current-voltage characteristics for the solar cells and atomic force microscope images of the substrate indicate that the parent wafer is undamaged, and is suitable for reuse after ELO and the protection-layer removal processes. X-ray photoelectron spectroscopy, reflection high-energy electron diffraction observation, and three-dimensional surface profiling show a surface that is comparable or improved to the original epiready wafer following ELO. Wafer reuse over multiple cycles suggests that high-efficiency; single-crystal thin-film solar cells may provide a practical path to low-cost solar-to-electrical energy conversion.

  13. Vertically aligned ZnO nanorods on porous silicon substrates: Effect of growth time

    Directory of Open Access Journals (Sweden)

    R. Shabannia

    2015-04-01

    Full Text Available Vertically aligned ZnO nanorods were successfully grown on porous silicon (PS substrates by chemical bath deposition at a low temperature. X-ray diffraction, field-emission scanning electron microscopy (FESEM, transmission electron microscopy (TEM, and photoluminescence (PL analyses were carried out to investigate the effect of growth duration (2 h to 8 h on the optical and structural properties of the aligned ZnO nanorods. Strong and sharp ZnO (0 0 2 peaks of the ZnO nanorods proved that the aligned ZnO nanorods were preferentially fabricated along the c-axis of the hexagonal wurtzite structure. FESEM images demonstrated that the ZnO nanorod arrays were well aligned along the c-axis and perpendicular to the PS substrates regardless of the growth duration. The TEM image showed that the top surfaces of the ZnO nanorods were round with a smooth curvature. PL spectra demonstrated that the ZnO nanorods grown for 5 h exhibited the sharpest and most intense PL peaks within the ultraviolet range among all samples.

  14. The growth and characterization of well aligned RuO2 nanorods on sapphire substrates

    International Nuclear Information System (INIS)

    Chen, C C; Chen, R S; Tsai, T Y; Huang, Y S; Tsai, D S; Tiong, K K

    2004-01-01

    Self-assembled and well aligned RuO 2 nanorods (NRs) have been grown on sapphire (SA) substrates via metal-organic chemical vapour deposition (MOCVD), using bis(ethylcyclopentadienyl)ruthenium as the source reagent. The surface morphology, structural, and spectroscopic properties of the as-deposited NRs were characterized using field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), selected-area electron diffractometry (SAD), x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and micro-Raman spectroscopy. FESEM micrographs reveal that vertically aligned nanorods (NRs) were grown on SA(100), while the NRs on the SA(012) were grown with a tilt angle of ∼ 35 degrees from the normal to the substrates. TEM and SAD measurements showed that the RuO 2 NRs with square cross-section have the long axis directed along the [001] direction. The XRD results indicate that the RuO 2 NRs are (002) oriented on SA(100) and (101) oriented on SA(012) substrates. A strong substrate effect on the alignment of the RuO 2 NRs growth has been demonstrated and the probable mechanism for the formation of these NRs has been discussed. XP spectra show the coexistence of higher oxidation state of ruthenium in the as-grown RuO 2 NRs. Micro-Raman spectra show the red-shift and peak broadening of the RuO 2 signatures with respect to that of the bulk counterpart which may be indicative of a phonon confinement effect for these NRs

  15. Time-dependent crack growth in steam generator tube leakage

    International Nuclear Information System (INIS)

    Chung, H.D.; Lee, J.H.; Park, Y.W.; Choi, Y.H.

    2006-01-01

    In general, cracks found in steam generator tubes have semi-elliptical shapes and it is assumed to be rectangular shape for conservatism after crack penetration. Hence, the leak and crack growth behavior has not been clearly understood after the elliptical crack penetrates the tube wall. Several experimental results performed by Argonne Nation Laboratory exhibited time-dependent crack growth behavior of rectangular flaws as well as trapezoidal flaws under constant pressure. The crack growth faster than expected was observed in both cases, which is likely attributed to time-dependent crack growth accompanied by fatigue sources such as the interaction between active jet and crack. The stress intensity factor, K 1 , is necessary for the prediction of the observed fatigue crack growth behavior. However, no K 1 solution is available for a trapezoidal flaw. The objective of this study is to develop the stress intensity factor which can be used for the fatigue analysis of a trapezoidal crack. To simplify the analysis, the crack is assumed to be a symmetric trapezoidal shape. A new K 1 formula for axial trapezoidal through-wall cracks was proposed based on the FEM results. (author)

  16. Resolving nanoparticle growth mechanisms from size- and time-dependent growth rate analysis

    Science.gov (United States)

    Pichelstorfer, Lukas; Stolzenburg, Dominik; Ortega, John; Karl, Thomas; Kokkola, Harri; Laakso, Anton; Lehtinen, Kari E. J.; Smith, James N.; McMurry, Peter H.; Winkler, Paul M.

    2018-01-01

    Atmospheric new particle formation occurs frequently in the global atmosphere and may play a crucial role in climate by affecting cloud properties. The relevance of newly formed nanoparticles depends largely on the dynamics governing their initial formation and growth to sizes where they become important for cloud microphysics. One key to the proper understanding of nanoparticle effects on climate is therefore hidden in the growth mechanisms. In this study we have developed and successfully tested two independent methods based on the aerosol general dynamics equation, allowing detailed retrieval of time- and size-dependent nanoparticle growth rates. Both methods were used to analyze particle formation from two different biogenic precursor vapors in controlled chamber experiments. Our results suggest that growth rates below 10 nm show much more variation than is currently thought and pin down the decisive size range of growth at around 5 nm where in-depth studies of physical and chemical particle properties are needed.

  17. Growth and characterization of InAs columnar quantum dots on GaAs substrate

    International Nuclear Information System (INIS)

    Li, L. H.; Patriarche, G.; Rossetti, M.; Fiore, A.

    2007-01-01

    The growth of InAs columnar quantum dots (CQDs) on GaAs substrates by molecular beam epitaxy was investigated. The CQDs were formed by depositing a 1.8 monolayer (ML) InAs seed dot layer and a short period GaAs/InAs superlattice (SL). It was found that the growth of the CQDs is very sensitive to growth interruption (GI) and growth temperature. Both longer GI and higher growth temperature impact the size dispersion of the CQDs, which causes the broadening of photoluminescence (PL) spectrum and the presence of the additional PL peak tails. By properly choosing the GI and the growth temperature, CQDs including GaAs (3 ML)/InAs (0.62 ML) SL with period number up to 35 without plastic relaxation were grown. The corresponding equivalent thickness of the SL is 41 nm which is two times higher than the theoretical critical thickness of the strained InGaAs layer with the same average In composition of 16%. The increase of the critical thickness is partially associated with the formation of the CQDs. Based on a five-stack CQD active region, laser diodes emitting around 1120 nm at room temperature were demonstrated, indicating a high material quality. CQDs with nearly isotropic cross section (20 nmx20 nm dimensions) were formed by depositing a 16-period GaAs (3 ML)/InAs (0.62 ML) SL on an InAs seed dot layer, indicating the feasibility of artificial shape engineering of QDs. Such a structure is expected to be very promising for polarization insensitive device applications, such as semiconductor optical amplifiers

  18. Study of molecular-beam epitaxy growth on patterned GaAs (311)A substrates with different mesa height

    NARCIS (Netherlands)

    Gong, Q.; Nötzel, R.; Schönherr, H.-P.; Ploog, K.

    2000-01-01

    We report on the evolution of the growth front during molecular-beam epitaxy on GaAs (3 1 1)A substrates stripe patterned along the [ ] direction as a function of the mesa height. During growth (1 0 0) and (2 1 1)A facets are formed and expand at the corners near the two opposite lying ( )A and (1 1

  19. A Xylenol Orange-Based Screening Assay for the Substrate Specificity of Flavin-Dependent para-Phenol Oxidases

    Directory of Open Access Journals (Sweden)

    Tom A. Ewing

    2018-01-01

    Full Text Available Vanillyl alcohol oxidase (VAO and eugenol oxidase (EUGO are flavin-dependent enzymes that catalyse the oxidation of para-substituted phenols. This makes them potentially interesting biocatalysts for the conversion of lignin-derived aromatic monomers to value-added compounds. To facilitate their biocatalytic exploitation, it is important to develop methods by which variants of the enzymes can be rapidly screened for increased activity towards substrates of interest. Here, we present the development of a screening assay for the substrate specificity of para-phenol oxidases based on the detection of hydrogen peroxide using the ferric-xylenol orange complex method. The assay was used to screen the activity of VAO and EUGO towards a set of twenty-four potential substrates. This led to the identification of 4-cyclopentylphenol as a new substrate of VAO and EUGO and 4-cyclohexylphenol as a new substrate of VAO. Screening of a small library of VAO and EUGO active-site variants for alterations in their substrate specificity led to the identification of a VAO variant (T457Q with increased activity towards vanillyl alcohol (4-hydroxy-3-methoxybenzyl alcohol and a EUGO variant (V436I with increased activity towards chavicol (4-allylphenol and 4-cyclopentylphenol. This assay provides a quick and efficient method to screen the substrate specificity of para-phenol oxidases, facilitating the enzyme engineering of known para-phenol oxidases and the evaluation of the substrate specificity of novel para-phenol oxidases.

  20. A Xylenol Orange-Based Screening Assay for the Substrate Specificity of Flavin-Dependent para-Phenol Oxidases.

    Science.gov (United States)

    Ewing, Tom A; van Noord, Aster; Paul, Caroline E; van Berkel, Willem J H

    2018-01-14

    Vanillyl alcohol oxidase (VAO) and eugenol oxidase (EUGO) are flavin-dependent enzymes that catalyse the oxidation of para -substituted phenols. This makes them potentially interesting biocatalysts for the conversion of lignin-derived aromatic monomers to value-added compounds. To facilitate their biocatalytic exploitation, it is important to develop methods by which variants of the enzymes can be rapidly screened for increased activity towards substrates of interest. Here, we present the development of a screening assay for the substrate specificity of para -phenol oxidases based on the detection of hydrogen peroxide using the ferric-xylenol orange complex method. The assay was used to screen the activity of VAO and EUGO towards a set of twenty-four potential substrates. This led to the identification of 4-cyclopentylphenol as a new substrate of VAO and EUGO and 4-cyclohexylphenol as a new substrate of VAO. Screening of a small library of VAO and EUGO active-site variants for alterations in their substrate specificity led to the identification of a VAO variant (T457Q) with increased activity towards vanillyl alcohol (4-hydroxy-3-methoxybenzyl alcohol) and a EUGO variant (V436I) with increased activity towards chavicol (4-allylphenol) and 4-cyclopentylphenol. This assay provides a quick and efficient method to screen the substrate specificity of para -phenol oxidases, facilitating the enzyme engineering of known para- phenol oxidases and the evaluation of the substrate specificity of novel para -phenol oxidases.

  1. Mutually exclusive STAT1 modifications identified by Ubc9/substrate dimerization-dependent SUMOylation.

    Science.gov (United States)

    Zimnik, Susan; Gaestel, Matthias; Niedenthal, Rainer

    2009-03-01

    Post-translational modifications control the physiological activity of the signal transducer and activator of transcription STAT1. While phosphorylation at tyrosine Y701 is a prerequisite for STAT1 dimerization, its SUMOylation represses the transcriptional activity. Recently, we have demonstrated that SUMOylation at lysine K703 inhibits the phosphorylation of nearby localized Y701 of STAT1. Here, we analysed the influence of phosphorylation of Y701 on SUMOylation of K703 in vivo. For that reason, an Ubc9/substrate dimerization-dependent SUMOylation (USDDS) system was developed, which consists of fusions of the SUMOylation substrate and of the SUMO-conjugating enzyme Ubc9 to the chemically activatable heterodimerization domains FKBP and FRB, respectively. When FKBP fusion proteins of STAT1, p53, CRSP9, FOS, CSNK2B, HES1, TCF21 and MYF6 are coexpressed with Ubc9-FRB, treatment of HEK293 cells with the rapamycin-related dimerizer compound AP21967 induces SUMOylation of these proteins in vivo. For STAT1-FKBP and p53-FKBP we show that this SUMOylation takes place at their specific SUMOylation sites in vivo. Using USDDS, we then demonstrate that STAT1 phosphorylation at Y701 induced by interferon-beta treatment inhibits SUMOylation of K703 in vivo. Thus, pY701 and SUMO-K703 of STAT1 represent mutually exclusive modifications, which prevent signal integration at this molecule and probably ensure the existence of differentially modified subpopulations of STAT1 necessary for its regulated nuclear cytoplasmic activation/inactivation cycle.

  2. Protein farnesyltransferase isoprenoid substrate discrimination is dependent on isoprene double bonds and branched methyl groups.

    Science.gov (United States)

    Micali, E; Chehade, K A; Isaacs, R J; Andres, D A; Spielmann, H P

    2001-10-16

    Farnesylation is a posttranslational lipid modification in which a 15-carbon farnesyl isoprenoid is linked via a thioether bond to specific cysteine residues of proteins in a reaction catalyzed by protein farnesyltransferase (FTase). We synthesized the benzyloxyisoprenyl pyrophosphate (BnPP) series of transferable farnesyl pyrophosphate (FPP) analogues (1a-e) to test the length dependence of the isoprenoid substrate on the FTase-catalyzed transfer of lipid to protein substrate. Kinetic analyses show that pyrophosphates 1a-e and geranyl pyrophosphate (GPP) transfer with a lower efficiency than FPP whereas geranylgeranyl pyrophosphate (GGPP) does not transfer at all. While a correlation was found between K(m) and analogue hydrophobicity and length, there was no correlation between k(cat) and these properties. Potential binding geometries of FPP, GPP, GGPP, and analogues 1a-e were examined by modeling the molecules into the active site of the FTase crystal structure. We found that analogue 1d displaces approximately the same volume of the active site as does FPP, whereas GPP and analogues 1a-c occupy lesser volumes and 1e occupies a slightly larger volume. Modeling also indicated that GGPP adopts a different conformation than the farnesyl chain of FPP, partially occluding the space occupied by the Ca(1)a(2)X peptide in the ternary X-ray crystal structure. Within the confines of the FTase pocket, the double bonds and branched methyl groups of the geranylgeranyl chain significantly restrict the number of possible conformations relative to the more flexible lipid chain of analogues 1a-e. The modeling results also provide a molecular explanation for the observation that an aromatic ring is a good isostere for the terminal isoprene of FPP.

  3. Evolution of space dependent growth in the teleost Astyanax mexicanus.

    Directory of Open Access Journals (Sweden)

    Natalya D Gallo

    Full Text Available The relationship between growth rate and environmental space is an unresolved issue in teleosts. While it is known from aquaculture studies that stocking density has a negative relationship to growth, the underlying mechanisms have not been elucidated, primarily because the growth rate of populations rather than individual fish were the subject of all previous studies. Here we investigate this problem in the teleost Astyanax mexicanus, which consists of a sighted surface-dwelling form (surface fish and several blind cave-dwelling (cavefish forms. Surface fish and cavefish are distinguished by living in spatially contrasting environments and therefore are excellent models to study the effects of environmental size on growth. Multiple controlled growth experiments with individual fish raised in confined or unconfined spaces showed that environmental size has a major impact on growth rate in surface fish, a trait we have termed space dependent growth (SDG. In contrast, SDG has regressed to different degrees in the Pachón and Tinaja populations of cavefish. Mating experiments between surface and Pachón cavefish show that SDG is inherited as a dominant trait and is controlled by multiple genetic factors. Despite its regression in blind cavefish, SDG is not affected when sighted surface fish are raised in darkness, indicating that vision is not required to perceive and react to environmental space. Analysis of plasma cortisol levels showed that an elevation above basal levels occurred soon after surface fish were exposed to confined space. This initial cortisol peak was absent in Pachón cavefish, suggesting that the effects of confined space on growth may be mediated partly through a stress response. We conclude that Astyanax reacts to confined spaces by exhibiting SDG, which has a genetic component and shows evolutionary regression during adaptation of cavefish to confined environments.

  4. Sintered tantalum carbide coatings on graphite substrates: Highly reliable protective coatings for bulk and epitaxial growth

    International Nuclear Information System (INIS)

    Nakamura, Daisuke; Suzumura, Akitoshi; Shigetoh, Keisuke

    2015-01-01

    Highly reliable low-cost protective coatings have been sought after for use in crucibles and susceptors for bulk and epitaxial film growth processes involving wide bandgap materials. Here, we propose a production technique for ultra-thick (50–200 μmt) tantalum carbide (TaC) protective coatings on graphite substrates, which consists of TaC slurry application and subsequent sintering processes, i.e., a wet ceramic process. Structural analysis of the sintered TaC layers indicated that they have a dense granular structure containing coarse grain with sizes of 10–50 μm. Furthermore, no cracks or pinholes penetrated through the layers, i.e., the TaC layers are highly reliable protective coatings. The analysis also indicated that no plastic deformation occurred during the production process, and the non-textured crystalline orientation of the TaC layers is the origin of their high reliability and durability. The TaC-coated graphite crucibles were tested in an aluminum nitride (AlN) sublimation growth process, which involves extremely corrosive conditions, and demonstrated their practical reliability and durability in the AlN growth process as a TaC-coated graphite. The application of the TaC-coated graphite materials to crucibles and susceptors for use in bulk AlN single crystal growth, bulk silicon carbide (SiC) single crystal growth, chemical vapor deposition of epitaxial SiC films, and metal-organic vapor phase epitaxy of group-III nitrides will lead to further improvements in crystal quality and reduced processing costs

  5. Sintered tantalum carbide coatings on graphite substrates: Highly reliable protective coatings for bulk and epitaxial growth

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Daisuke; Suzumura, Akitoshi; Shigetoh, Keisuke [Toyota Central R and D Labs., Inc., Nagakute, Aichi 480-1192 (Japan)

    2015-02-23

    Highly reliable low-cost protective coatings have been sought after for use in crucibles and susceptors for bulk and epitaxial film growth processes involving wide bandgap materials. Here, we propose a production technique for ultra-thick (50–200 μmt) tantalum carbide (TaC) protective coatings on graphite substrates, which consists of TaC slurry application and subsequent sintering processes, i.e., a wet ceramic process. Structural analysis of the sintered TaC layers indicated that they have a dense granular structure containing coarse grain with sizes of 10–50 μm. Furthermore, no cracks or pinholes penetrated through the layers, i.e., the TaC layers are highly reliable protective coatings. The analysis also indicated that no plastic deformation occurred during the production process, and the non-textured crystalline orientation of the TaC layers is the origin of their high reliability and durability. The TaC-coated graphite crucibles were tested in an aluminum nitride (AlN) sublimation growth process, which involves extremely corrosive conditions, and demonstrated their practical reliability and durability in the AlN growth process as a TaC-coated graphite. The application of the TaC-coated graphite materials to crucibles and susceptors for use in bulk AlN single crystal growth, bulk silicon carbide (SiC) single crystal growth, chemical vapor deposition of epitaxial SiC films, and metal-organic vapor phase epitaxy of group-III nitrides will lead to further improvements in crystal quality and reduced processing costs.

  6. In situ observation of carbon nanotube layer growth on microbolometers with substrates at ambient temperature

    Science.gov (United States)

    Svatoš, Vojtěch; Gablech, Imrich; Ilic, B. Robert; Pekárek, Jan; Neužil, Pavel

    2018-03-01

    Carbon nanotubes (CNTs) have near unity infrared (IR) absorption efficiency, making them extremely attractive for IR imaging devices. Since CNT growth occurs at elevated temperatures, the integration of CNTs with IR imaging devices is challenging and has not yet been achieved. Here, we show a strategy for implementing CNTs as IR absorbers using differential heating of thermally isolated microbolometer membranes in a C2H2 environment. During the process, CNTs were catalytically grown on the surface of a locally heated membrane, while the substrate was maintained at an ambient temperature. CNT growth was monitored in situ in real time using optical microscopy. During growth, we measured the intensity of light emission and the reflected light from the heated microbolometer. Our measurements of bolometer performance show that the CNT layer on the surface of the microbolometer membrane increases the IR response by a factor of (2.3 ± 0.1) (mean ± one standard deviation of the least-squares fit parameters). This work opens the door to integrating near unity IR absorption, CNT-based, IR absorbers with hybrid complementary metal-oxide-semiconductor focal plane array architectures.

  7. Solid-support substrates for plant growth at a lunar base

    Science.gov (United States)

    Ming, D. W.; Galindo, C.; Henninger, D. L.

    1990-01-01

    Zeoponics is only in its developmental stages at the Johnson Space Center and is defined as the cultivation of plants in zeolite substrates that contain several essential plant growth cations on their exchange sites, and have minor amounts of mineral phases and/or anion-exchange resins that supply essential plant growth anions. Zeolites are hydrated aluminosilicates of alkali and alkaline earth cations with the ability to exchange most of their constituent exchange cations as well as hydrate/dehydrate without change to their structural framework. Because zeolites have extremely high cation exchange capabilities, they are very attractive media for plant growth. It is possible to partially or fully saturate plant-essential cations on zeolites. Zeoponic systems will probably have their greatest applications at planetary bases (e.g., lunar bases). Lunar raw materials will have to be located that are suited for the synthesis of zeolites and other exchange resings. Lunar 'soil' simulants have been or are being prepared for zeolite/smectite synthesis and 'soil' dissolution studies.

  8. Growth and nutrient balance of Enterolobium contortsiliquum seedlings with addition of organic substrates and wastewater

    Directory of Open Access Journals (Sweden)

    Emanuel França Araújo

    2016-06-01

    Full Text Available Given the strong generation of solid organic waste and wastewater, the use of these materials as a primary source of nutrients is an important practice in environmental management, especially in the production of seedlings with emphasis on degraded areas. The objective of this study was to evaluate growth and nutrient balance of “tamboril” (Enterolobium contortsiliquum (Vell. Morong seedlings grown on substrates with different formulations proportions of organic matter irrigated with wastewater. It was tested five ratios of organic composts and soil: 0:100; 20:80; 40:60; 60:40 and 80:20 v/v. Two procedences of irrigation water was tested: water supply and wastewater from swine farming, arranged in a completely randomized design in a factorial scheme 5 x 2, with four replications. At 90 days, we evaluate seedlings morphological variables, the integrate diagnosis recommendation index and the nutrient balance index. The organic residue contributes to seedlings growth and nutritional balance. The proportion 80:20 proved to be the most suitable for “tamboril” seedlings production. Seedlings presented lower growth and nutritional balance when irrigate with swine farm wastewater.

  9. Growth and characterization of thick cBN coatings on silicon and tool substrates

    International Nuclear Information System (INIS)

    Bewilogua, K.; Keunecke, M.; Weigel, K.; Wiemann, E.

    2004-01-01

    Recently some research groups have achieved progress in the deposition of cubic boron nitride (cBN) coatings with a thickness of 2 μm and more, which is necessary for cutting tool applications. In our laboratory, thick cBN coatings were sputter deposited on silicon substrates using a boron carbide target. Following a boron carbide interlayer (few 100 nm thick), a gradient layer with continuously increasing nitrogen content was prepared. After the cBN nucleation, the process parameters were modified for the cBN film growth to a thickness of more than 2 μm. However, the transfer of this technology to technically relevant substrates, like cemented carbide cutting inserts, required some further process modifications. At first, a titanium interlayer had to be deposited followed by a more than 1-μm-thick boron carbide layer. The next steps were identical to those on silicon substrates. The total coating thickness was in the range of 3 μm with a 0.5- to nearly 1-μm-thick cBN top layer. In spite of the enormous intrinsic stress, both the coatings on silicon and on cemented carbide exhibited a good adhesion and a prolonged stability in humid air. Oxidation experiments revealed a stability of the coating system on cemented carbide up to 700 deg. C and higher. Coated cutting inserts were tested in turning operations with different metallic workpiece materials. The test results will be compared to those of well-established cutting materials, like polycrystalline cubic boron nitride (PCBN) and oxide ceramics, considering the wear of coated tools

  10. Homo- and heteroepitaxial growth behavior of upright InAs nanowires on InAs and GaAs substrates

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Jens; Gottschalch, Volker; Paetzelt, Hendrik [Institut fuer Anorganische Chemie, Universitaet Leipzig, Johannesallee 29, D-04103 Leipzig (Germany); Wagner, Gerald [Institut fuer Kristallographie und Mineralogie, Universitaet Leipzig, Linnestr. 5, D-04103 Leipzig (Germany); Pietsch, Ulrich [Festkoerperphysik, Universitaet Siegen, D-57068 Siegen (Germany)

    2008-07-01

    Semiconductor nanowires (NW) acquire recently attraction because of promising new application fields in electronics and optoelectronic. We applied the vapor-liquid-solid mechanism with gold seeds in combination with low-pressure metal-organic vapor phase epitaxy (LP-MOVPE) to achieve replicable InAs NW growth with high growth rates. Since the initial alloying of the gold seeds with the substrate material plays a deciding role for the inceptive NW growth, InAs free standing nanowires were grown on GaAs(111)B substrate as well as on InAs/GaAs(111)B quasi-substrate. The influence of the MOVPE parameters will be discussed with respect to NW morphology and real-structure. A special focus will be set on the heteroepitaxial InAs NW growth on GaAs substrates. Gracing-incidence X-ray studies and transmission electron microscopy investigations revealed the existence of a thin Ga{sub x}In{sub 1-x}As graduated alloy layer with embedded crystalline gold alloy particles at the NW substrate interface. The effect of droplet composition on the VLS growth will be presented in a thermodynamic model.

  11. Evolutionary selection growth of two-dimensional materials on polycrystalline substrates

    Science.gov (United States)

    Vlassiouk, Ivan V.; Stehle, Yijing; Pudasaini, Pushpa Raj; Unocic, Raymond R.; Rack, Philip D.; Baddorf, Arthur P.; Ivanov, Ilia N.; Lavrik, Nickolay V.; List, Frederick; Gupta, Nitant; Bets, Ksenia V.; Yakobson, Boris I.; Smirnov, Sergei N.

    2018-03-01

    There is a demand for the manufacture of two-dimensional (2D) materials with high-quality single crystals of large size. Usually, epitaxial growth is considered the method of choice1 in preparing single-crystalline thin films, but it requires single-crystal substrates for deposition. Here we present a different approach and report the synthesis of single-crystal-like monolayer graphene films on polycrystalline substrates. The technological realization of the proposed method resembles the Czochralski process and is based on the evolutionary selection2 approach, which is now realized in 2D geometry. The method relies on `self-selection' of the fastest-growing domain orientation, which eventually overwhelms the slower-growing domains and yields a single-crystal continuous 2D film. Here we have used it to synthesize foot-long graphene films at rates up to 2.5 cm h-1 that possess the quality of a single crystal. We anticipate that the proposed approach could be readily adopted for the synthesis of other 2D materials and heterostructures.

  12. The influence of substrate type and chlormequat on the growth and flowering of marigold (Tagetes L.

    Directory of Open Access Journals (Sweden)

    Maślanka Małgorzata

    2017-12-01

    Full Text Available This study was conducted to investigate the effect of various horticultural substrates (compost, peat-coconut, peat TS1, flower soil, lowmoor peat and a foliar spray of chlormequat (at a concentration of 1380 mg dm-3 on the growth and flowering of the marigold cultivars belonging to two species: Tagetes erecta - ʻMarvel Mixtureʼ and ʻTaishan Orangeʼ, and Tagetes patula - ʻDurango Redʼ and ʻBonanza Flameʼ. The obtained results show that the plants grown in peat TS1 and peat-coconut were taller, had longer internodes and leaves, and thicker stems than the plants grown in the other substrates. Chlormequat significantly reduced the height of ʻMarvel Mixtureʼ (in peat TS1, ʻTaishan Orangeʼ (in lowmoor peat and ‘Bonanza Flameʼ (in peat-coconut. The use of chlormequat also accelerated the development of flower heads in ʻTaishan Orangeʼ (in lowmoor peat.

  13. Gold nanoparticle growth control - Implementing novel wet chemistry method on silicon substrate

    KAUST Repository

    Al-Ameer, Ammar

    2013-04-01

    Controlling particle size, shape, nucleation, and self-assembly on surfaces are some of the main challenges facing electronic device fabrication. In this work, growth of gold nanoparticles over a wide range of sizes was investigated by using a novel wet chemical method, where potassium iodide is used as the reducing solution and gold chloride as the metal precursor, on silicon substrates. Four parameters were studied: soaking time, solution temperature, concentration of the solution of gold chloride, and surface pre-treatment of the substrate. Synthesized nanoparticles were then characterized using scanning electron microscopy (SEM). The precise control of the location and order of the grown gold overlayer was achieved by using focused ion beam (FIB) patterning of a silicon surface, pre-treated with potassium iodide. By varying the soaking time and temperature, different particle sizes and shapes were obtained. Flat geometrical shapes and spherical shapes were observed. We believe, that the method described in this work is potentially a straightforward and efficient way to fabricate gold contacts for microelectronics. © 2013 IEEE.

  14. Direct growth of graphene on quartz substrate as saturable absorber for femtosecond solid-state laser

    International Nuclear Information System (INIS)

    Xu, S C; Man, B Y; Jiang, S Z; Chen, C S; Liu, M; Yang, C; Gao, S B; Zhang, C; Feng, D J; Huang, Q J; Hu, G D; Chen, X F

    2014-01-01

    We present a novel method for the direct metal-free growth of graphene on quartz substrate. The direct-grown graphene yields excellent nonlinear saturable absorption properties and is demonstrated to be suitable as a saturable absorber (SA) for an ultrafast solid-state laser. Nearly Fourier-limited 367 fs was obtained at a central wavelength of 1048 nm with a repetition rate of 105.7 MHz. At a pump power of 7.95 W, the average output power was 1.93 W and the highest pulse energy reached 18.3 nJ, with a peak power of 49.8 kW. Our work opens an easy route for making a reliable graphene SA with a mode-locking technique and also displays an exciting prospect in making low-cost and ultrafast lasers. (letter)

  15. Direct growth of graphene on quartz substrates for label-free detection of adenosine triphosphate.

    Science.gov (United States)

    Xu, Shicai; Man, Baoyuan; Jiang, Shouzhen; Yue, Weiwei; Yang, Cheng; Liu, Mei; Chen, Chuansong; Zhang, Chao

    2014-04-25

    We demonstrate that continuous, uniform graphene films can be directly synthesized on quartz substrates using a two-temperature-zone chemical vapor deposition system and that their layers can be controlled by adjusting the precursor partial pressure. Raman spectroscopy and transmission electron microscopy confirm the formation of monolayer graphene with a grain size of ∼100 nm. Hall measurements show a room-temperature carrier mobility above 1500 cm2 V(-1) s(-1). The optical transmittance and conductance of the graphene films are comparable to those of transferred metal-catalyzed graphene. The method avoids the complicated and skilled post-growth transfer process and allows the graphene to be directly incorporated into a fully functional biosensor for label-free detection of adenosine triphosphate (ATP). This device shows a fast response time of a few milliseconds and achieves a high sensitivity to ATP molecules over a very wide range from 0.002 to 5 mM.

  16. Heteroepitaxial Growth of Vacuum-Evaporated Si-Ge Films on Nano structured Silicon Substrates

    International Nuclear Information System (INIS)

    Ayu Wazira Azhari; Ayu Wazira Azhari; Kamaruzzaman Sopian; Saleem Hussain Zaidi

    2015-01-01

    In this study, a low-cost vacuum-evaporated technique is used in the heteroepitaxial growth of Si-Ge films. Three different surface variations are employed: for example polished Si, Si micro pyramids and Si nano pillars profiles. A simple metal-assisted chemical etching method is used to fabricate the Si nano pillars, with Ag acting as a catalyst. Following deposition, substrates are subjected to post-deposition thermal annealing at 1000 degree Celsius to improve the crystallinity of the Ge layer. Optical and morphological studies of surface area are conducted using field emission scanning electron microscopy (FE-SEM), Energy Dispersive X-ray (EDX), Raman spectroscopy and infrared spectroscopy. From the infrared spectroscopy analysis, the energy bandgap for Si-Ge films is estimated to be around 0.94 eV. This high-quality Si-Ge film is most favourable for optics, optoelectronics and high-efficiency solar cell applications. (author)

  17. Growth and quantum transport properties of vertical Bi2Se3 nanoplate films on Si substrates.

    Science.gov (United States)

    Li, M Z; Wang, Z H; Yang, L; Pan, D S; Li, Da; Gao, Xuan; Zhang, Zhi-Dong

    2018-05-14

    Controlling the growth direction (planar vs. vertical) and surface-to-bulk ratio can lead to lots of unique properties for two-dimensional (2D) layered materials. We report a simple method to fabricate continuous films of vertical Bi2Se3 nanoplates on Si substrate and investigate the quantum transport properties of such films. In contrast to (001) oriented planar Bi2Se3 nanoplate film, vertical Bi2Se3 nanoplate films are enclosed by (015) facets, which possess high surface-to-bulk ratio that can enhance the quantum transport property of topological surface states. And by controlling the compactness of vertical Bi2Se3 nanoplates, we realized an effective tuning of the weak antilocalization (WAL) effect from topological surface states in Bi2Se3 films. Our work paves a way for exploring the unique transport properties of this unconventional structure topological insulator film. © 2018 IOP Publishing Ltd.

  18. Study of carbide-forming element interlayers for diamond nucleation and growth on silicon and WC-Co substrates

    International Nuclear Information System (INIS)

    Tang, Y.; Li, Y.S.; Yang, Q.; Hirose, A.

    2010-01-01

    Diamond nucleation and growth on several typical carbide-forming elements (CFE) (Ti, Cr and W) coated Si and WC-Co substrates were studied. The ion beam sputtered CFE interlayers show an amorphous/nanocrystalline microstructure. The diamond formed on the CFE coated substrates shows higher nucleation density and rate and finer grain structure than on uncoated substrates. Consequently, nanocrystalline diamond thin films can be formed on the CFE coated substrates under conventional microcrystalline diamond growth conditions. Among the three tested CFE interlayers, diamond has the highest nucleation density and rate on W layer and the lowest on Ti layer. The diamond nucleation density and rate on CFE coated WC-Co are much higher than those on widely used metal nitride coated WC-Co.

  19. Tolerance of GaAs as an original substrate for HVPE growth of free standing GaN

    Science.gov (United States)

    Suzuki, Mio; Sato, T.; Suemasu, T.; Hasegawa, F.

    2004-09-01

    In order to investigate possibility of thick GaN growth on a GaAs substrate by halide vapar phase epitaxy (HVPE), GaN was grown on GaAs(111)/Ti wafer with Ti deposited by E-gun. It was found that surface treatment of the GaAs substrate by HF solution deteriorated greatly the tolerence of GaAs and that Ti can protected GaAs from erosion by NH3. By depositing Ti on GaAs(111)A surface, a millor-like GaN layer could be grown at 1000 °C for 1 hour without serious deterioration of the original GaAs substrate. By increasing the growth rate, a thick free standing GaN will be obtained with GaAs as an original substrate in near future.

  20. Tolerance of GaAs as an original substrate for HVPE growth of free standing GaN

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Mio; Sato, T.; Suemasu, T.; Hasegawa, F. [University of Tsukuba, Institute of Applied Physics, Tsukuba, Ibaraki 305-8573 (Japan)

    2004-09-01

    In order to investigate possibility of thick GaN growth on a GaAs substrate by halide vapar phase epitaxy (HVPE), GaN was grown on GaAs(111)/Ti wafer with Ti deposited by E-gun. It was found that surface treatment of the GaAs substrate by HF solution deteriorated greatly the tolerance of GaAs and that Ti can protected GaAs from erosion by NH{sub 3}. By depositing Ti on GaAs(111)A surface, a mirror-like GaN layer could be grown at 1000 C for 1 hour without serious deterioration of the original GaAs substrate. By increasing the growth rate, a thick free standing GaN will be obtained with GaAs as an original substrate in near future. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Selective area growth of GaN rod structures by MOVPE: Dependence on growth conditions

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shunfeng; Fuendling, Soenke; Wang, Xue; Erenburg, Milena; Al-Suleiman, Mohamed Aid Mansur; Wei, Jiandong; Wehmann, Hergo-Heinrich; Waag, Andreas [Institut fuer Halbleitertechnik, TU Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany); Bergbauer, Werner [Institut fuer Halbleitertechnik, TU Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany); Osram Opto Semiconductors GmbH, Leibnizstr. 4, 93055 Regensburg (Germany); Strassburg, Martin [Osram Opto Semiconductors GmbH, Leibnizstr. 4, 93055 Regensburg (Germany)

    2011-07-15

    Selective area growth of GaN nanorods by metalorganic vapor phase epitaxy is highly demanding for novel applications in nano-optoelectronic and nanophotonics. Recently, we report the successful selective area growth of GaN nanorods in a continuous-flow mode. In this work, as examples, we show the morphology dependence of GaN rods with {mu}m or sub-{mu}m in diameters on growth conditions. Firstly, we found that the nitridation time is critical for the growth, with an optimum from 90 to 180 seconds. This leads to more homogeneous N-polar GaN rods growth. A higher temperature during GaN rod growth tends to increase the aspect ratio of the GaN rods. This is due to the enhanced surface diffusion of growth species. The V/III ratio is also an important parameter for the GaN rod growth. Its increase causes reduction of the aspect ratio of GaN rods, which could be explained by the relatively lower growth rate on (000-1) N-polar top surface than it on {l_brace}1-100{r_brace} m-planes by supplying more NH{sub 3} (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Aerobic Degradation of Trichloroethylene by Co-Metabolism Using Phenol and Gasoline as Growth Substrates

    Directory of Open Access Journals (Sweden)

    Yan Li

    2014-05-01

    Full Text Available Trichloroethylene (TCE is a common groundwater contaminant of toxic and carcinogenic concern. Aerobic co-metabolic processes are the predominant pathways for TCE complete degradation. In this study, Pseudomonas fluorescens was studied as the active microorganism to degrade TCE under aerobic condition by co-metabolic degradation using phenol and gasoline as growth substrates. Operating conditions influencing TCE degradation efficiency were optimized. TCE co-metabolic degradation rate reached the maximum of 80% under the optimized conditions of degradation time of 3 days, initial OD600 of microorganism culture of 0.14 (1.26 × 107 cell/mL, initial phenol concentration of 100 mg/L, initial TCE concentration of 0.1 mg/L, pH of 6.0, and salinity of 0.1%. The modified transformation capacity and transformation yield were 20 μg (TCE/mg (biomass and 5.1 μg (TCE/mg (phenol, respectively. Addition of nutrient broth promoted TCE degradation with phenol as growth substrate. It was revealed that catechol 1,2-dioxygenase played an important role in TCE co-metabolism. The dechlorination of TCE was complete, and less chlorinated products were not detected at the end of the experiment. TCE could also be co-metabolized in the presence of gasoline; however, the degradation rate was not high (28%. When phenol was introduced into the system of TCE and gasoline, TCE and gasoline could be removed at substantial rates (up to 59% and 69%, respectively. This study provides a promising approach for the removal of combined pollution of TCE and gasoline.

  3. Time-dependent crack growth and fracture in concrete

    International Nuclear Information System (INIS)

    Zhou Fan Ping.

    1992-02-01

    The objectives of this thesis are to study time-dependent fracture behaviour in concrete. The thesis consists of an experimental study, costitutive modelling and numerical analysis. The experimental study was undertaken to investigate the influences of time on material properties for the fracture process zone and on crack growth and fracture in plain concrete structures. The experiments include tensile relaxation tests, bending tests on notched beams to determine fracture energy at varying deflection rates, and sustained bending and compact tensile tests. From the tensile relaxation tests, the envelope of the σ-w relation does not seem to be influenced by holding periods, though some local detrimental effect does occur. Fracture energy seems to decrease as rates become slower. In the sustained loading tests, deformation (deflection or CMOD) growth curves display three stages, as usually observed in a creep rupture test. The secondary stage dominates the whole failure lifetime, and the secondary deformation rate appears to have good correlation with the failure lifetime. A crack model for time-dependent fracture is proposed, by applying the idea of the Fictitious Crack Model. In this model, a modified Maxwell model is introduced for the fracture process zone incorporated with the static σ-w curve as a failure criterion, based on the observation of the tensile relaxation tests. The time-dependent σ-w curve is expressed in an incremental law. The proposed model has been implemented in a finite element program and applied to simulating sustained flexural and compact tensile tests. Numerical analysis includes simulations of crack growth, load-CMOD curves, stress-failure lifetime curves, size effects on failure life etc. The numerical results indicate that the model seems to be able to properly predict the main features of time-dependent fracture behaviour in concrete, as compared with the experimental results. 97 refs

  4. Direct Growth of High-Quality InP Layers on GaAs Substrates by MOCVD

    Directory of Open Access Journals (Sweden)

    K. F. Yarn

    2003-01-01

    group V partial pressure, growth rate and V/III ratios. A mirror-like, uniform surface and high crystal quality of the metamorphic buffer layer directly grown on a GaAs substrate can be achieved. Finally, to investigate the performance of the metamorphic microwave devices, we also fabricate the InAlAs/InGaAs metamorphic HEMT on GaAs substrates.

  5. High Quality, Low Cost Bulk Gallium Nitride Substrates Grown by the Electrochemical Solution Growth Method

    Energy Technology Data Exchange (ETDEWEB)

    Seacrist, Michael [SunEdison Inc., St. Peters, MO (United States)

    2017-08-15

    The objective of this project was to develop the Electrochemical Solution Growth (ESG) method conceived / patented at Sandia National Laboratory into a commercially viable bulk gallium nitride (GaN) growth process that can be scaled to low cost, high quality, and large area GaN wafer substrate manufacturing. The goal was to advance the ESG growth technology by demonstrating rotating seed growth at the lab scale and then transitioning process to prototype commercial system, while validating the GaN material and electronic / optical device quality. The desired outcome of the project is a prototype commercial process for US-based manufacturing of high quality, large area, and lower cost GaN substrates that can drive widespread deployment of energy efficient GaN-based power electronic and optical devices. In year 1 of the project (Sept 2012 – Dec 2013) the overall objective was to demonstrate crystalline GaN growth > 100um on a GaN seed crystal. The development plan included tasks to demonstrate and implement a method for purifying reagent grade salts, develop the reactor 1 process for rotating seed Electrochemical Solution Growth (ESG) of GaN, grow and characterize ESG GaN films, develop a fluid flow and reaction chemistry model for GaN film growth, and design / build an improved growth reactor capable of scaling to 50mm seed diameter. The first year’s project objectives were met in some task areas including salt purification, film characterization, modeling, and reactor 2 design / fabrication. However, the key project objective of the growth of a crystalline GaN film on the seed template was not achieved. Amorphous film growth on the order of a few tenths of a micron has been detected with a film composition including Ga and N, plus several other impurities originating from the process solution and hardware. The presence of these impurities, particularly the oxygen, has inhibited the demonstration of crystalline GaN film growth on the seed template. However, the

  6. Nanoscale imaging of the growth and division of bacterial cells on planar substrates with the atomic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Van Der Hofstadt, M. [Institut de Bioenginyeria de Catalunya (IBEC), C/ Baldiri i Reixac 11-15, 08028 Barcelona (Spain); Hüttener, M.; Juárez, A. [Institut de Bioenginyeria de Catalunya (IBEC), C/ Baldiri i Reixac 11-15, 08028 Barcelona (Spain); Departament de Microbiologia, Universitat de Barcelona, Avinguda Diagonal 645, 08028 Barcelona (Spain); Gomila, G., E-mail: ggomila@ibecbarcelona.eu [Institut de Bioenginyeria de Catalunya (IBEC), C/ Baldiri i Reixac 11-15, 08028 Barcelona (Spain); Departament d' Electronica, Universitat de Barcelona, C/ Marti i Franqués 1, 08028 Barcelona (Spain)

    2015-07-15

    With the use of the atomic force microscope (AFM), the Nanomicrobiology field has advanced drastically. Due to the complexity of imaging living bacterial processes in their natural growing environments, improvements have come to a standstill. Here we show the in situ nanoscale imaging of the growth and division of single bacterial cells on planar substrates with the atomic force microscope. To achieve this, we minimized the lateral shear forces responsible for the detachment of weakly adsorbed bacteria on planar substrates with the use of the so called dynamic jumping mode with very soft cantilever probes. With this approach, gentle imaging conditions can be maintained for long periods of time, enabling the continuous imaging of the bacterial cell growth and division, even on planar substrates. Present results offer the possibility to observe living processes of untrapped bacteria weakly attached to planar substrates. - Highlights: • Gelatine coatings used to weakly attach bacterial cells onto planar substrates. • Use of the dynamic jumping mode as a non-perturbing bacterial imaging mode. • Nanoscale resolution imaging of unperturbed single living bacterial cells. • Growth and division of single bacteria cells on planar substrates observed.

  7. Bonding temperature dependence of GaInAsP/InP laser diode grown on hydrophilically directly bonded InP/Si substrate

    Science.gov (United States)

    Aikawa, Masaki; Onuki, Yuya; Hayasaka, Natsuki; Nishiyama, Tetsuo; Kamada, Naoki; Han, Xu; Kallarasan Periyanayagam, Gandhi; Uchida, Kazuki; Sugiyama, Hirokazu; Shimomura, Kazuhiko

    2018-02-01

    The bonding-temperature-dependent lasing characteristics of 1.5 a µm GaInAsP laser diode (LD) grown on a directly bonded InP/Si substrate were successfully obtained. We have fabricated the InP/Si substrate using a direct hydrophilic wafer bonding technique at bonding temperatures of 350, 400, and 450 °C, and deposited GaInAsP/InP double heterostructure layers on this InP/Si substrate. The surface conditions, X-ray diffraction (XRD) analysis, photoluminescence (PL) spectra, and electrical characteristics after the growth were compared at these bonding temperatures. No significant differences were confirmed in X-ray diffraction analysis and PL spectra at these bonding temperatures. We realized the room-temperature lasing of the GaInAsP LD on the InP/Si substrate bonded at 350 and 400 °C. The threshold current densities were 4.65 kA/cm2 at 350 °C and 4.38 kA/cm2 at 400 °C. The electrical resistance was found to increase with annealing temperature.

  8. Molten Salt-Based Growth of Bulk GaN and InN for Substrates

    Energy Technology Data Exchange (ETDEWEB)

    Waldrip, Karen Elizabeth [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Power Sources Technology Dept.; Tsao, Jeffrey Yeenien [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Energy Sciences Dept.; Kerley, Thomas M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Materials Sciences Dept.

    2006-09-01

    An atmospheric pressure approach to growth of bulk group III-nitrides is outlined. Native III-nitride substrates for optoelectronic and high power, high frequency electronics are desirable to enhance performance and reliability of these devices; currently, these materials are available in research quantities only for GaN, and are unavailable in the case of InN. The thermodynamics and kinetics of the reactions associated with traditional crystal growth techniques place these activities on the extreme edges of experimental physics. The technique described herein relies on the production of the nitride precursor (N3-) by chemical and/or electrochemical methods in a molten halide salt. This nitride ion is then reacted with group III metals in such a manner as to form the bulk nitride material. The work performed during the period of funding (July 2004-September 2005) focused on the initial measurement of the solubility of GaN in molten LiCl as a function of temperature, the construction of electrochemical cells, the modification of a commercial glove box (required for handling very hygroscopic LiCl), and on securing intellectual property for the technique.

  9. Radiation effects on time-dependent deformation: Creep and growth

    International Nuclear Information System (INIS)

    Simonen, E.P.

    1989-03-01

    Observations of irradiation creep strain as well as irradiation growth strain and related microstructures are reviewed and compared to mechanisms for radiation effects on time-dependent deformation. Composition, microstructure, stress and temperature affect irradiation creep less than thermal creep. Irradiation creep rates can often dominate thermal creep rates, particularly at low temperatures and low stresses. Irradiation creep mechanisms are classified in two general categories: (1) stress-induced preferential absorption and (2) climb-glide. In the former, creep results from dislocation climb, whereas in the latter, creep results from dislocation glide. The effects of irradiation creep on failure modes in nuclear environments are discussed. 53 refs., 18 figs., 1 tab

  10. GaMnAs on patterned GaAs(001) substrates: Growth and magnetotransport

    Energy Technology Data Exchange (ETDEWEB)

    Daeubler, Joachim; Glunk, Michael; Hummel, Thomas; Schoch, Wladimir; Limmer, Wolfgang; Sauer, Rolf [Institut fuer Halbleiterphysik, Universitaet Ulm, 89069 Ulm (Germany)

    2007-07-01

    A new type of GaMnAs microstructures with laterally confined electronic and magnetic properties has been realized in a bottom-up procedure by growing GaMnAs films on [1 anti 10]-oriented ridge structures with (113)A sidewalls and (001) top layers prepared on GaAs(001) substrates. Previous studies on planar GaMnAs samples have revealed different incorporation of Mn and excess As in (001) and (113)A layers. Accordingly, temperature- and field-dependent magnetotransport measurements on the overgrown ridge structures clearly demonstrate the coexistence of electronic and magnetic properties specific for (001) and (113)A GaMnAs in one single sample. This introduces an additional degree of freedom in the development of new functional structures.

  11. Surface morphology of polyethylene glycol films produced by matrix-assisted pulsed laser evaporation (MAPLE): Dependence on substrate temperature

    DEFF Research Database (Denmark)

    Rodrigo, K.; Czuba, P.; Toftmann, B.

    2006-01-01

    The dependence of the surface morphology on the substrate temperature during film deposition was investigated for polyethylene glycol (PEG) films by matrix-assisted pulsed laser evaporation (MAPLE). The surface structure was studied with a combined technique of optical imaging and AFM measurements...

  12. SNOSite: exploiting maximal dependence decomposition to identify cysteine S-nitrosylation with substrate site specificity.

    Directory of Open Access Journals (Sweden)

    Tzong-Yi Lee

    Full Text Available S-nitrosylation, the covalent attachment of a nitric oxide to (NO the sulfur atom of cysteine, is a selective and reversible protein post-translational modification (PTM that regulates protein activity, localization, and stability. Despite its implication in the regulation of protein functions and cell signaling, the substrate specificity of cysteine S-nitrosylation remains unknown. Based on a total of 586 experimentally identified S-nitrosylation sites from SNAP/L-cysteine-stimulated mouse endothelial cells, this work presents an informatics investigation on S-nitrosylation sites including structural factors such as the flanking amino acids composition, the accessible surface area (ASA and physicochemical properties, i.e. positive charge and side chain interaction parameter. Due to the difficulty to obtain the conserved motifs by conventional motif analysis, maximal dependence decomposition (MDD has been applied to obtain statistically significant conserved motifs. Support vector machine (SVM is applied to generate predictive model for each MDD-clustered motif. According to five-fold cross-validation, the MDD-clustered SVMs could achieve an accuracy of 0.902, and provides a promising performance in an independent test set. The effectiveness of the model was demonstrated on the correct identification of previously reported S-nitrosylation sites of Bos taurus dimethylarginine dimethylaminohydrolase 1 (DDAH1 and human hemoglobin subunit beta (HBB. Finally, the MDD-clustered model was adopted to construct an effective web-based tool, named SNOSite (http://csb.cse.yzu.edu.tw/SNOSite/, for identifying S-nitrosylation sites on the uncharacterized protein sequences.

  13. Design and development of green roof substrate to improve runoff water quality: plant growth experiments and adsorption.

    Science.gov (United States)

    Vijayaraghavan, K; Raja, Franklin D

    2014-10-15

    Many studies worldwide have investigated the potential benefits achievable by transforming brown roofs of buildings to green roofs. However, little literature examined the runoff quality/sorption ability of green roofs. As the green roof substrate is the main component to alter the quality of runoff, this investigation raises the possibility of using a mixture of low-cost inorganic materials to develop a green roof substrate. The tested materials include exfoliated vermiculite, expanded perlite, crushed brick and sand along with organic component (coco-peat). Detailed physical and chemical analyses revealed that each of these materials possesses different characteristics and hence a mix of these materials was desirable to develop an optimal green roof substrate. Using factorial design, 18 different substrate mixes were prepared and detailed examination indicated that mix-12 exhibited desirable characteristics of green roof substrate with low bulk density (431 kg/m(3)), high water holding capacity (39.4%), air filled porosity (19.5%), and hydraulic conductivity (4570 mm/h). The substrate mix also provided maximum support to Portulaca grandiflora (380% total biomass increment) over one month of growth. To explore the leaching characteristics and sorption capacity of developed green roof substrate, a down-flow packed column arrangement was employed. High conductivity and total dissolved solids along with light metal ions (Na, K, Ca and Mg) were observed in the leachates during initial stages of column operation; however the concentration of ions ceased during the final stages of operation (600 min). Experiments with metal-spiked deionized water revealed that green roof substrate possess high sorption capacity towards various heavy metal ions (Al, Fe, Cr, Cu, Ni, Pb, Zn and Cd). Thus the developed growth substrate possesses desirable characteristics for green roofs along with high sorption capacity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Substrate dependence of TM-polarized light emission characteristics of BAlGaN/AlN quantum wells

    Science.gov (United States)

    Park, Seoung-Hwan; Ahn, Doyeol

    2018-06-01

    To study the substrate dependence of light emission characteristics of transverse-magnetic (TM)-polarized light emitted from BAlGaN/AlN quantum wells (QWs) grown on GaN and AlN substrates were investigated theoretically. It is found that the topmost valence subband for QW structures grown on AlN substrate, is heavy hole state (HH1) while that for QW structures grown on GaN substrate is crystal-field split off light hole state (CL1), irrespective of the boron content. Since TM-polarized light emission is associated with the light hole state, the TM-polarized emission peak of BAlGaN/AlN QW structures grown on GaN substrate is expected to be much larger than that of the QW structure grown on AlN substrate. Also, both QW structures show that the spontaneous emission peak of BAlGaN/AlN QW structures would be improved with the inclusion of the boron. However, it rapidly begins to decrease when the boron content exceeds a critical value.

  15. Cultured representatives of two major phylogroups of human colonic Faecalibacterium prausnitzii can utilize pectin, uronic acids, and host-derived substrates for growth.

    Science.gov (United States)

    Lopez-Siles, Mireia; Khan, Tanweer M; Duncan, Sylvia H; Harmsen, Hermie J M; Garcia-Gil, L Jesús; Flint, Harry J

    2012-01-01

    Faecalibacterium prausnitzii is one of the most abundant commensal bacteria in the healthy human large intestine, but information on genetic diversity and substrate utilization is limited. Here, we examine the phylogeny, phenotypic characteristics, and influence of gut environmental factors on growth of F. prausnitzii strains isolated from healthy subjects. Phylogenetic analysis based on the 16S rRNA sequences indicated that the cultured strains were representative of F. prausnitzii sequences detected by direct analysis of fecal DNA and separated the available isolates into two phylogroups. Most F. prausnitzii strains tested grew well under anaerobic conditions on apple pectin. Furthermore, F. prausnitzii strains competed successfully in coculture with two other abundant pectin-utilizing species, Bacteroides thetaiotaomicron and Eubacterium eligens, with apple pectin as substrate, suggesting that this species makes a contribution to pectin fermentation in the colon. Many F. prausnitzii isolates were able to utilize uronic acids for growth, an ability previously thought to be confined to Bacteroides spp. among human colonic anaerobes. Most strains grew on N-acetylglucosamine, demonstrating an ability to utilize host-derived substrates. All strains tested were bile sensitive, showing at least 80% growth inhibition in the presence of 0.5 μg/ml bile salts, while inhibition at mildly acidic pH was strain dependent. These attributes help to explain the abundance of F. prausnitzii in the colonic community but also suggest factors in the gut environment that may limit its distribution.

  16. Substrate and metabolite diffusion within model medium for soft cheese in relation to growth of Penicillium camembertii.

    Science.gov (United States)

    Aldarf, Mazen; Fourcade, Florence; Amrane, Abdeltif; Prigent, Yves

    2006-08-01

    Penicillium camembertii was cultivated on a jellified peptone-lactate based medium to simulate the composition of Camembert cheese. Diffusional limitations due to substrate consumption were not involved in the linear growth recorded during culture, while nitrogen (peptone) limitation accounted for growth cessation. Examination of gradients confirmed that medium neutralization was the consequence of lactate consumption and ammonium production. The diffusion of the lactate assimilated from the core to the rind and that of the ammonium produced from the rind to the core was described by means of a diffusion/reaction model involving a partial linking of consumption or production to growth. The model matched experimental data throughout growth.

  17. Growth pattern and growth dependent mortality of larval and pelagic juvenile North Sea cod Gadus morhua

    DEFF Research Database (Denmark)

    Nielsen, Rune; Munk, Peter

    2004-01-01

    and May 2001), and larval/juvenile growth history from each of the sampling sequences was outlined. Growth rate was estimated by fitting a Laird-Gompertz equation to lengths-at-age, and we found the mean specific growth rate in length at age 20 d was 3.2% d(-1), declining to 1.9% d(-1) at an age of 90 d....... Otolith radius and larval standard length were highly correlated, and otolith growth was used as a measure of larval somatic growth. The larvae were divided into 3 groups dependent on their hatch-date, and for each hatch group, the same period of past growth was compared between fish sampled in April...... and May. A 2-way repeated-measurement ANOVA revealed a significant higher past growth of fish sampled in May in 2 of the 3 hatch-groups, implying a higher mortality of the slow growing larvae. Additionally, otolith size at age differed significantly between the April and May sampling of the oldest larvae...

  18. Metabolic efficiency in yeast Saccharomyces cerevisiae in relation to temperature dependent growth and biomass yield.

    Science.gov (United States)

    Zakhartsev, Maksim; Yang, Xuelian; Reuss, Matthias; Pörtner, Hans Otto

    2015-08-01

    Canonized view on temperature effects on growth rate of microorganisms is based on assumption of protein denaturation, which is not confirmed experimentally so far. We develop an alternative concept, which is based on view that limits of thermal tolerance are based on imbalance of cellular energy allocation. Therefore, we investigated growth suppression of yeast Saccharomyces cerevisiae in the supraoptimal temperature range (30-40°C), i.e. above optimal temperature (Topt). The maximal specific growth rate (μmax) of biomass, its concentration and yield on glucose (Yx/glc) were measured across the whole thermal window (5-40°C) of the yeast in batch anaerobic growth on glucose. Specific rate of glucose consumption, specific rate of glucose consumption for maintenance (mglc), true biomass yield on glucose (Yx/glc(true)), fractional conservation of substrate carbon in product and ATP yield on glucose (Yatp/glc) were estimated from the experimental data. There was a negative linear relationship between ATP, ADP and AMP concentrations and specific growth rate at any growth conditions, whilst the energy charge was always high (~0.83). There were two temperature regions where mglc differed 12-fold, which points to the existence of a 'low' (within 5-31°C) and a 'high' (within 33-40°C) metabolic mode regarding maintenance requirements. The rise from the low to high mode occurred at 31-32°C in step-wise manner and it was accompanied with onset of suppression of μmax. High mglc at supraoptimal temperatures indicates a significant reduction of scope for growth, due to high maintenance cost. Analysis of temperature dependencies of product formation efficiency and Yatp/glc revealed that the efficiency of energy metabolism approaches its lower limit at 26-31°C. This limit is reflected in the predetermined combination of Yx/glc(true), elemental biomass composition and degree of reduction of the growth substrate. Approaching the limit implies a reduction of the safety margin

  19. Growth of nano hexagon-like flake arrays cerium carbonate created with PAH as the substrate

    Energy Technology Data Exchange (ETDEWEB)

    Li, M., E-mail: limei@imust.cn [School of Materials Science and Engineering, Beijing University of Chemical Engineering, Department of Materials, Beijing 100029 (China); School of Materials and Metallurgy, Inner Mongolia University of Science and Technology, Department of Inorganic and Metalloid Materials, Key Laboratory of New Technologies of Modern Metallurgy and Application of Rare Materials, Baotou 014010 (China); Hu, Y.H., E-mail: bthyh@163.com [School of Materials Science and Engineering, Beijing University of Chemical Engineering, Department of Materials, Beijing 100029 (China); School of Materials and Metallurgy, Inner Mongolia University of Science and Technology, Department of Inorganic and Metalloid Materials, Key Laboratory of New Technologies of Modern Metallurgy and Application of Rare Materials, Baotou 014010 (China); Liu, Z.G.; Wang, X.F.; Wang, M.T. [School of Materials and Metallurgy, Inner Mongolia University of Science and Technology, Department of Inorganic and Metalloid Materials, Key Laboratory of New Technologies of Modern Metallurgy and Application of Rare Materials, Baotou 014010 (China)

    2015-01-15

    Petals-like Ce{sub 2}(CO{sub 3}){sub 3} on Ce{sub 2}(CO{sub 3}){sub 3} nano hexagon-like flake arrays have been precipitatingly fabricated using PAH substrates. By changing the way of feeding, PAH concentration and aging time, petals-like Ce{sub 2}(CO{sub 3}){sub 3} was created best when adding PAH into the Ce(NO{sub 3}){sub 3} solution, joined (NH{sub 4}){sub 2}CO{sub 3} solution along with mixing, PAH concentration is 0.9 g/L, aging time is 4 h. A growth mechanism was proposed to account for the growth of the petals-like Ce{sub 2}(CO{sub 3}){sub 3} with PAH as the substrate. Poly allylamine hydrochloride (PAH) is as template agent which forms π-allyl complex with Ce{sup 3+} and controls the morphology of Ce{sub 2}(CO{sub 3}){sub 3} particle. PAH and Ce{sup 3+} form π-allyl complex, and then induce the formation of Ce{sub 2}(CO{sub 3}){sub 3} crystal nucleus. And infrared spectrum analysis verified. XRD show that after adding PAH which is adsorbed on the crystal plane, the growth of Ce{sub 2}(CO{sub 3}){sub 3} crystal is inhibited on (2 4 2), the growth is promoted on (2 0 2) which is differentiated into the new (1 5 1), (2 2 2) is unchanged, Ce{sub 2}(CO{sub 3}){sub 3} crystal is accumulated petals shape by hexagon-like flake. UV absorption spectra show that CeO{sub 2} as prepared precursor Ce{sub 2}(CO{sub 3}){sub 3} after calcinations in air at high temperatures, the petal-like CeO{sub 2} has strong UV absorption and reflection effects, and absorption interval changed significantly by the move to UVA from UVB. - Graphical abstract: Each Ce-atom connects three Cl-atoms and three allyls in three dimensional spaces. To take the plane as a reference plane which is arrayed with three Ce-atom as equilateral triangle. The triangular each vertex is Ce-atom, the triangular center place is Cl-atom, the equilateral triangle which is mutually perpendicular with Ce-triangle surface and the inclined angle is 60° is made up with three Cl-atoms. - Highlights: • Petals

  20. Substrate dependence of electron-stimulated O - yields from dissociative electron attachment to physisorbed O2

    Science.gov (United States)

    Huels, M. A.; Parenteau, L.; Sanche, L.

    1994-03-01

    We present measurements of O- electron stimulated desorption yields obtained under identical experimental conditions from 0.15 monolayers (ML) of O2 deposited onto disordered substrates consisting of 4 ML of either Kr, Xe, C2H6, C2H4, N2O, CH3Cl, or H2O, all condensed on Pt (polycrystalline). The resulting O- yield functions, for incident electron energies below 20 eV, are compared to that obtained from the O2/Kr solid; this allows us to assess the order of magnitude effects of the local substrate environment on dissociative electron attachment (DEA) via the 2Πu and gas phase forbidden 2Σ+g,u resonances of O-2. We note that, in addition to electron energy losses in the substrate prior to DEA to O2 and post-dissociation interactions of the O- with the substrate molecules, charge or energy transfer from the O-2 transient anion to a substrate molecule, and capture of the incident electron into a dissociative anion resonance of the substrate molecule may contribute to a reduced O- yield from the physisorbed O2. In the case of O2 deposited on amorphous ice, we find that the O- signal from DEA to O2 is completely absent for electron energies below 14 eV; we attribute this to a complete quenching of the dissociative O-2(2Πu, 2Σ+) resonances by the adjacent water molecules.

  1. Temperature sensitivity of soil respiration is dependent on readily decomposable C substrate concentration

    Science.gov (United States)

    Larionova, A. A.; Yevdokimov, I. V.; Bykhovets, S. S.

    2007-06-01

    Temperature acclimation of soil organic matter (SOM) decomposition is one of the major uncertainties in predicting soil CO2 efflux by the increase in global mean temperature. A reasonable explanation for an apparent acclimation proposed by Davidson and colleagues (2006) based on Michaelis-Menten kinetics suggests that temperature sensitivity decreases when both maximal activity of respiratory enzymes (Vmax) and half- saturation constant (Ks) cancel each other upon temperature increase. We tested the hypothesis of the canceling effect by the mathematical simulation of the data obtained in the incubation experiments with forest and arable soils. Our data confirm the hypothesis and suggest that concentration of readily decomposable C substrate as glucose equivalent is an important factor controlling temperature sensitivity. The highest temperature sensitivity was observed when C substrate concentration was much lower than Ks. Increase of substrate content to the half-saturation constant resulted in temperature acclimation associated with the canceling effect. Addition of the substrate to the level providing respiration at a maximal rate Vmax leads to the acclimation of the whole microbial community as such. However, growing microbial biomass was more sensitive to the temperature alterations. This study improves our understanding of the instability of temperature sensitivity of soil respiration under field conditions, explaining this phenomenon by changes in concentration of readily decomposable C substrate. It is worth noting that this pattern works regardless of the origin of C substrate: production by SOM decomposition, release into the soil by rhizodeposition, litter fall or drying-rewetting events.

  2. Remote and direct plasma regions for low-temperature growth of carbon nanotubes on glass substrates for display applications

    International Nuclear Information System (INIS)

    Tabatabaei, M K; Ghafouri fard, H; Koohsorkhi, J; Khatami, S; Mohajerzadeh, S

    2011-01-01

    A novel method for growing carbon nanotubes (CNTs) on glass substrates is introduced in this study. A two-stage plasma was used to achieve low-temperature and vertically aligned CNTs. Ni deposited on indium tin oxide/glass substrate was used as the catalyst and hydrogen and acetylene were used as gas feeds. In this investigation a new technique was developed to grow vertically aligned CNTs at temperatures below 400 deg. C while CNT growth by plasma-enhanced chemical vapour deposition required high temperatures. Low-temperature growth of vertically aligned CNTs was suitable for the fabrication of micro-lens and self-oriented displays on glass substrates. Also, we have reported a new configuration for CNT-based display by means of controlling the refractive index of liquid crystal around the CNT by applying a proper voltage to the top and bottom array.

  3. Epitaxial growth of YBa2Cu3O7-δ thin films on LiNbO3 substrates

    International Nuclear Information System (INIS)

    Lee, S.G.; Koren, G.; Gupta, A.; Segmuller, A.; Chi, C.C.

    1989-01-01

    In situ epitaxial growth of YBa 2 Cu 3 O 7-δ thin films on Y-cut LiNbO 3 substrates using a standard laser ablation technique is reported. Resistance of the films shows a normal metallic behavior and a very sharp ( c (R=0) of 92 K. High critical current density of J c (77 K)=2x10 5 A/cm 2 is observed, which is in accordance with epitaxial growth. Film orientation observed from x-ray diffraction spectra indicates that the c axis is normal to the substrate plane and the a axis is at 45 degree to the [11.0] direction of the hexagonal lattice of the substrate with two domains in mirror image to the (110) plane

  4. Influence of periphyton substrates and rearing density on Liza aurata growth and production in marine nursery ponds

    NARCIS (Netherlands)

    Richard, M.; Maurice, J.T.; Anginot, A.; Paticat, F.; Verdegem, M.C.J.; Hussenot, J.M.E.

    2010-01-01

    The main objectives of this investigation were to test the effects of (i) the presence of periphyton substrates, (ii) rearing density and (iii) supplemental feeding with dry feed on the growth and production of golden mullet (Liza aurata) juveniles. Twenty-six 1 m2-cages were installed in a French

  5. The Effect of Nitrogen Form on pH and Petunia Growth in a WholeTree Substrate

    Science.gov (United States)

    The objective of our research was to investigate the effect of nitrogen form and proportion on peat-lite (PL) and WholeTree (WT) substrate pH and petunia growth. Chipped whole pine trees (consisting of needles, limbs, bark, wood and cones) were obtained from a commercial fuel wood chipping operation...

  6. Control by substrate of the cytochrome p450-dependent redox machinery: mechanistic insights.

    Science.gov (United States)

    Hlavica, Peter

    2007-08-01

    Based on initial studies with bacterial CYP101A1, a popular concept emerged predicting that substrate-induced low-to-high spin conversion of P450s is universally associated with shifts of the midpoint potential to a more positive value to maximize rates of electron transfer and metabolic turnover. However, evaluation of the plethora of observations with pro- and eukaryotic hemoproteins suggests a caveat as to generalization of this principle. Thus, some P450s are inherently high-spin, so that there is no need for a supportive substrate-triggered impulse to electron flow. With other enzymes, high-spin content is not consonant with reductive activity, and spin transition as such is not essential to sustaining substrate oxidation. Also, with certain proteins the low-spin conformer is reduced as swift as the high-spin entity. Moreover, there is not regularly a linear relationship between high-spin level and anodic shift of the reduction potential. Similarly, in given cases turnover may proceed despite insignificant or even lacking substrate-provoked alterations in the redox behaviour. Thus, folding of the disparate and sometimes conflicting data into a harmonized overall picture is a lingering problem. Apart from direct perturbation of the electrochemical properties, substrate docking may entail changes in enzyme conformation such as to favour productive complexation with redox partners or modulate electron transfer conduits within preformed donor/acceptor adducts, resulting in elevated ease of flow of reducing equivalents. Substrate-steered ordering of the oligomeric aggregation state of P450s is likely to impose steric constraints on heterodimers, causing one component to more readily align with electron carriers. Careful uncovering of electrochemical mechanisms in these systems will be fruitful to tailoring of novel bioenergetic machines and redox chains via redox-inspired protein engineering or molecular Lego, capable of generating products of interest or degrading

  7. Biochar increases plant growth and alters microbial communities via regulating the moisture and temperature of green roof substrates.

    Science.gov (United States)

    Chen, Haoming; Ma, Jinyi; Wei, Jiaxing; Gong, Xin; Yu, Xichen; Guo, Hui; Zhao, Yanwen

    2018-09-01

    Green roofs have increasingly been designed and applied to relieve environmental problems, such as water loss, air pollution as well as heat island effect. Substrate and vegetation are important components of green roofs providing ecosystem services and benefiting the urban development. Biochar made from sewage sludge could be potentially used as the substrate amendment for green roofs, however, the effects of biochar on substrate quality and plant performance in green roofs are still unclear. We evaluated the effects of adding sludge biochar (0, 5, 10, 15 and 20%, v/v) to natural soil planted with three types of plant species (ryegrass, Sedum lineare and cucumber) on soil properties, plant growth and microbial communities in both green roof and ground ecosystems. Our results showed that sludge biochar addition significantly increased substrate moisture, adjusted substrate temperature, altered microbial community structure and increased plant growth. The application rate of 10-15% sludge biochar on the green roof exerted the most significant effects on both microbial and plant biomass by 63.9-89.6% and 54.0-54.2% respectively. Path analysis showed that biochar addition had a strong effect on microbial biomass via changing the soil air-filled porosity, soil moisture and temperature, and promoted plant growth through the positive effects on microbial biomass. These results suggest that the applications of biochar at an appropriate rate can significantly alter plant growth and microbial community structure, and increase the ecological benefits of green roofs via exerting effects on the moisture, temperature and nutrients of roof substrates. Copyright © 2018 Elsevier B.V. All rights reserved.

  8. Properties of nickel films growth by radio frequency magnetron sputtering at elevated substrate temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Muslim, Noormariah, E-mail: 14h8702@ubd.edu.bn [Centre for Advanced Material and Energy Sciences, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong BE1410 (Brunei Darussalam); Soon, Ying Woan [Centre for Advanced Material and Energy Sciences, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong BE1410 (Brunei Darussalam); Physical and Geological Sciences, Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong BE1410 (Brunei Darussalam); Lim, Chee Ming; Voo, Nyuk Yoong [Centre for Advanced Material and Energy Sciences, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong BE1410 (Brunei Darussalam)

    2016-08-01

    Pure nickel (Ni) thin films of thicknesses of 100 nm were deposited on glass substrates by radio frequency magnetron sputtering at a power of 100 W and at various substrate temperatures i.e., room temperature, 100, 200, and 300 °C. The crystalline structure, surface topography, surface morphology, electrical resistivity, and optical properties of the deposited films were studied. The properties of the Ni films could be controlled by altering the substrate temperature. Specifically, the films featured a face-centered cubic crystalline structure with predominant (111) crystallite orientation at all the substrate temperatures employed, as observed from the X-ray diffraction analysis. Films deposited at substrate temperatures greater than 200 °C additionally displayed crystalline (200) and (220) diffraction peaks. The surface morphology analysis revealed that the grain size of the Ni thin films increased with increasing substrate temperatures employed. This increase was accompanied with a decrease in the resistivity of the Ni films. The surface roughness of the films increased with increasing substrate temperatures employed, as observed from the atomic force microscopy analysis. - Highlights: • RF magnetron sputtering is a good alternative method to deposit Ni films. • Properties of Ni films could be controlled simply by tuning substrate temperatures. • Crystallite size and surface roughness increased with substrate temperatures. • Electrical resistivity reduced with increasing substrate temperatures. • Optical properties also changed with substrate temperatures.

  9. Growth and characterization of AlxGa1-xN LEO substrates

    International Nuclear Information System (INIS)

    Paek, H.S.; Sakong, T.; Lee, S.N.; Son, J.K.; Ryu, H.Y.; Nam, O.H.; Park, Y.

    2006-01-01

    We have studied the effect of Al composition on the properties of Al x Ga 1-x N LEO substrates. Al x Ga 1-x N LEO substrates were prepared on stripe-patterned 2μm-thick undoped GaN/sapphire substrates by metalorganic chemical vapor deposition. To investigate the dislocation and crack density, and the surface morphology of Al x Ga 1-x N LEO substrates with different Al compositions, photoluminescence and optical microscope were used. At a 1% of Al composition, we obtained crack-free and mirror-like substrates having a low dislocation density of ∼1E6cm -2 . We expect considerable reduction in threshold current density to be achieved from blue-violet laser diodes grown on Al x Ga 1-x N LEO substrates because of the increased optical gain, as compared to the laser diodes grown on Al-free LEO substrates

  10. Bootstrapping as a Resource Dependence Management Strategy and its Association with Startup Growth

    OpenAIRE

    T. VANACKER; S. MANIGART; M. MEULEMAN; L. SELS

    2011-01-01

    This paper studies the association between bootstrapping and startup growth. Bootstrapping reduces a startup’s dependence on financial investors, but may create new dependencies. Drawing upon resource dependence theory, we hypothesize that when bootstrapping does not create new strong dependencies it will benefit startup growth, especially when dependence from financial investors is high. However, when bootstrapping creates new strong dependencies it will constrain growth, especially when dep...

  11. Temperature-dependent thermal conductivity of flexible yttria-stabilized zirconia substrate via 3ω technique

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Shivkant; Yarali, Milad; Mavrokefalos, Anastassios [Department of Mechanical Engineering, University of Houston, Houston, TX (United States); Shervin, Shahab [Materials Science and Engineering Program, University of Houston, Houston, TX (United States); Venkateswaran, Venkat; Olenick, Kathy; Olenick, John A. [ENrG Inc., Buffalo, NY (United States); Ryou, Jae-Hyun [Department of Mechanical Engineering, University of Houston, Houston, TX (United States); Materials Science and Engineering Program, University of Houston, Houston, TX (United States); Texas Center for Superconductivity, University of Houston (TcSUH), Houston, TX (United States)

    2017-10-15

    Thermal management in flexible electronic has proven to be challenging thereby limiting the development of flexible devices with high power densities. To truly enable the technological implementation of such devices, it is imperative to develop highly thermally conducting flexible substrates that are fully compatible with large-scale fabrication. Here, we present the thermal conductivity of state-of-the-art flexible yttria-stabilized zirconia (YSZ) substrates measured using the 3ω technique, which is already commercially manufactured via roll-to-roll technique. We observe that increasing the grain size increases the thermal conductivity of the flexible 3 mol.% YSZ, while the flexibility and transparency of the sample are hardly affected by the grain size enlargement. We exhibit thermal conductivity values of up to 4.16 Wm{sup -1}K {sup -1} that is at least 4 times higher than state-of-the-art polymeric flexible substrates. Phonon-hopping model (PHM) for granular material was used to fit the measured thermal conductivity and accurately define the thermal transport mechanism. Our results show that through grain size optimization, YSZ flexible substrates can be realized as flexible substrates, that pave new avenues for future novel application in flexible electronics through the utilization of both their ceramic structural flexibility and high heat dissipating capability. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Direct growth of graphene on quartz substrates for label-free detection of adenosine triphosphate

    International Nuclear Information System (INIS)

    Xu, Shicai; Man, Baoyuan; Jiang, Shouzhen; Yue, Weiwei; Yang, Cheng; Liu, Mei; Chen, Chuansong; Zhang, Chao

    2014-01-01

    We demonstrate that continuous, uniform graphene films can be directly synthesized on quartz substrates using a two-temperature-zone chemical vapor deposition system and that their layers can be controlled by adjusting the precursor partial pressure. Raman spectroscopy and transmission electron microscopy confirm the formation of monolayer graphene with a grain size of ∼100 nm. Hall measurements show a room-temperature carrier mobility above 1500 cm 2  V −1  s −1 . The optical transmittance and conductance of the graphene films are comparable to those of transferred metal-catalyzed graphene. The method avoids the complicated and skilled post-growth transfer process and allows the graphene to be directly incorporated into a fully functional biosensor for label-free detection of adenosine triphosphate (ATP). This device shows a fast response time of a few milliseconds and achieves a high sensitivity to ATP molecules over a very wide range from 0.002 to 5 mM. (paper)

  13. High Performance Bioanode Development for Fermentable Substrates via Controlled Electroactive Biofilm Growth

    Energy Technology Data Exchange (ETDEWEB)

    Ichihashi, Osamu [ORNL; Vishnivetskaya, Tatiana A [ORNL; Borole, Abhijeet P [ORNL

    2014-11-11

    A bioanode was optimized to generate current densities reaching 38.4 4.9 A m-2, which brings bioelectrochemical systems closer to commercial consideration. Glucose and lactate were fed together in a continuous or fed-batch mode. The current density increased from 2.3 A m-2 to 38.4 A m-2 over a 33 day period and remained stable thereafter. The coulombic efficiency ranged from 50% to 80%. A change in substrate concentration from 200 mg L-1 to 5 mg L-1 decreased maximum current density from 38.4 A m-2 to 12.3 A m-2. The anode consortia included Firmicutes (55.0%), Proteobacteria (41.8%) and Bacteroidetes (2.1%) constituting two potential electrogenic genera: Geobacter (6.8%) and Aeromonas (31.9%). The current production was found to be limited by kinetics during the growth period (33 days), and mass transfer, thereafter. The results indicate the necessity of removing spent biomass for efficient long term operation and treatment of wastewater streams.

  14. The controlled growth of GaN microrods on Si(111) substrates by MOCVD

    Science.gov (United States)

    Foltynski, Bartosz; Garro, Nuria; Vallo, Martin; Finken, Matthias; Giesen, Christoph; Kalisch, Holger; Vescan, Andrei; Cantarero, Andrés; Heuken, Michael

    2015-03-01

    In this paper, a selective area growth (SAG) approach for growing GaN microrods on patterned SiNx/Si(111) substrates by metal-organic chemical vapor deposition (MOCVD) is studied. The surface morphology, optical and structural properties of vertical GaN microrods terminated by pyramidal shaped facets (six { 10 1 bar 1} planes) were characterized using scanning electron microscopy (SEM), room temperature photoluminescence (PL) and Raman spectroscopy, respectively. Measurements revealed high-quality GaN microcolumns grown with silane support. Characterized structures were grown nearly strain-free (central frequency of Raman peak of 567±1 cm-1) with crystal quality comparable to bulk crystals (FWHM=4.2±1 cm-1). Such GaN microrods might be used as a next-generation device concept for solid-state lighting (SSL) applications by realizing core-shell InGaN/GaN multi-quantum wells (MQWs) on the n-GaN rod base.

  15. Substrate dependence of energy level alignment at the donor-acceptor interface in organic photovoltaic devices

    International Nuclear Information System (INIS)

    Zhou, Y.C.; Liu, Z.T.; Tang, J.X.; Lee, C.S.; Lee, S.T.

    2009-01-01

    The interface energy level alignment between copper phthalocyanine (CuPC) and fullerene (C60), the widely studied donor-acceptor pair in organic photovoltaics (OPVs), on indium-tin oxide (ITO) and Mg substrate was investigated. The CuPC/C60 interface formed on ITO shows a nearly common vacuum level, but a dipole and band bending exist, resulting in a 0.8 eV band offset at the same interface on Mg. This observation indicates that the energy difference between the highest occupied molecular orbital of CuPC and the lowest unoccupied molecular orbital of C60, which dictates the open circuit voltage of the CuPC/C60 OPV, can be tuned by the work function of the substrate. Furthermore, the substrate effect on the energy alignment at the donor/acceptor interface can satisfactorily explain that a device with an anode of a smaller work function can provide a higher open circuit voltage.

  16. Temperature dependence of critical current and transport current losses of 4 mm YBCO coated conductors manufactured using nonmagnetic substrate

    Science.gov (United States)

    Kvitkovic, J.; Hatwar, R.; Pamidi, S. V.; Fleshler, S.; Thieme, C.

    2015-12-01

    The temperature dependence of the critical current and AC losses were measured on American Superconductor Corporation's (AMSC) second generation high temperature superconducting (2G HTS) wire produced by Rolling Assisted Biaxially Textured Substrate (RABiTS) and Metal Organic Deposition (MOD) process. Wires manufactured with two types of substrates were characterized. The magnetic substrate with composition Ni5a%W exhibits a magnetic signature and has non-negligible AC losses in AC power applications. A new nonmagnetic substrate with an alloy composition Ni9a%W has been developed by AMSC to address the AC losses in 2G HTS. The data presented show that the performance of the new conductor is identical to the conductor with magnetic substrate in terms of critical current density. The data on AC losses demonstrate the absence of ferromagnetic loss component in the new conductor and significantly reduced AC losses at low to moderate values of I/Ic. The reduced losses will translate into reduced capital costs and lower operating costs of superconducting electrical devices for AC applications.

  17. Threonine deaminase from extremely halophilic bacteria - Cooperative substrate kinetics and salt dependence.

    Science.gov (United States)

    Lieberman, M. M.; Lanyi, J. K.

    1972-01-01

    The effect of salt on the activity, stability, and allosteric properties of catabolic threonine deaminase from Halobacterium cutirubrum was studied. The enzyme exhibits sigmoidal kinetics with the substrate, threonine. The Hill slope is 1.55 at pH 10. The enzyme is activated by ADP at low substrate concentrations. In the presence of this effector, sigmoidal kinetics are no longer observed. At pH 10, in the absence of ADP, enzyme activity increases with increasing NaCl concentration from 0 to 4 M.

  18. Concentration dependence of biotransformation in fish liver S9: Optimizing substrate concentrations to estimate hepatic clearance for bioaccumulation assessment.

    Science.gov (United States)

    Lo, Justin C; Allard, Gayatri N; Otton, S Victoria; Campbell, David A; Gobas, Frank A P C

    2015-12-01

    In vitro bioassays to estimate biotransformation rate constants of contaminants in fish are currently being investigated to improve bioaccumulation assessments of hydrophobic contaminants. The present study investigates the relationship between chemical substrate concentration and in vitro biotransformation rate of 4 environmental contaminants (9-methylanthracene, pyrene, chrysene, and benzo[a]pyrene) in rainbow trout (Oncorhynchus mykiss) liver S9 fractions and methods to determine maximum first-order biotransformation rate constants. Substrate depletion experiments using a series of initial substrate concentrations showed that in vitro biotransformation rates exhibit strong concentration dependence, consistent with a Michaelis-Menten kinetic model. The results indicate that depletion rate constants measured at initial substrate concentrations of 1 μM (a current convention) could underestimate the in vitro biotransformation potential and may cause bioconcentration factors to be overestimated if in vitro biotransformation rates are used to assess bioconcentration factors in fish. Depletion rate constants measured using thin-film sorbent dosing experiments were not statistically different from the maximum depletion rate constants derived using a series of solvent delivery-based depletion experiments for 3 of the 4 test chemicals. Multiple solvent delivery-based depletion experiments at a range of initial concentrations are recommended for determining the concentration dependence of in vitro biotransformation rates in fish liver fractions, whereas a single sorbent phase dosing experiment may be able to provide reasonable approximations of maximum depletion rates of very hydrophobic substances. © 2015 SETAC.

  19. Atomic force microscopy investigation of growth process of organic TCNQ aggregates on SiO2 and mica substrates

    Science.gov (United States)

    Huan, Qing; Hu, Hao; Pan, Li-Da; Xiao, Jiang; Du, Shi-Xuan; Gao, Hong-Jun

    2010-08-01

    Deposition patterns of tetracyanoquinodimethane (TCNQ) molecules on different surfaces are investigated by atomic force microscopy. A homemade physical vapour deposition system allows the better control of molecule deposition. Taking advantage of this system, we investigate TCNQ thin film growth on both SiO2 and mica surfaces. It is found that dense island patterns form at a high deposition rate, and a unique seahorse-like pattern forms at a low deposition rate. Growth patterns on different substrates suggest that the fractal pattern formation is dominated by molecule-molecule interaction. Finally, a phenomenal “two-branch" model is proposed to simulate the growth process of the seahorse pattern.

  20. Atomic force microscopy investigation of growth process of organic TCNQ aggregates on SiO2 and mica substrates

    International Nuclear Information System (INIS)

    Qing, Huan; Hao, Hu; Li-Da, Pan; Jiang, Xiao; Shi-Xuan, Du; Hong-Jun, Gao

    2010-01-01

    Deposition patterns of tetracyanoquinodimethane (TCNQ) molecules on different surfaces are investigated by atomic force microscopy. A homemade physical vapour deposition system allows the better control of molecule deposition. Taking advantage of this system, we investigate TCNQ thin film growth on both SiO 2 and mica surfaces. It is found that dense island patterns form at a high deposition rate, and a unique seahorse-like pattern forms at a low deposition rate. Growth patterns on different substrates suggest that the fractal pattern formation is dominated by molecule–molecule interaction. Finally, a phenomenal “two-branch” model is proposed to simulate the growth process of the seahorse pattern. (general)

  1. A novel, substrate independent three-step process for the growth of uniform ZnO nanorod arrays

    International Nuclear Information System (INIS)

    Byrne, D.; McGlynn, E.; Henry, M.O.; Kumar, K.; Hughes, G.

    2010-01-01

    We report a three-step deposition process for uniform arrays of ZnO nanorods, involving chemical bath deposition of aligned seed layers followed by nanorod nucleation sites and subsequent vapour phase transport growth of nanorods. This combines chemical bath deposition techniques, which enable substrate independent seeding and nucleation site generation with vapour phase transport growth of high crystalline and optical quality ZnO nanorod arrays. Our data indicate that the three-step process produces uniform nanorod arrays with narrow and rather monodisperse rod diameters (∼ 70 nm) across substrates of centimetre dimensions. X-ray photoelectron spectroscopy, scanning electron microscopy and X-ray diffraction were used to study the growth mechanism and characterise the nanostructures.

  2. Effects of substrate anisotropy and edge diffusion on submonolayer growth during molecular beam epitaxy: A Kinetic Monte Carlo study

    International Nuclear Information System (INIS)

    Devkota, J.; Shrestha, S.P.

    2007-12-01

    We have performed Kinetic Monte Carlo simulation work to study the effect of diffusion anisotropy, bonding anisotropy and edge diffusion on island formation at different temperatures during the sub-monolayer film growth in Molecular Beam Epitaxy. We use simple cubic solid on solid model and event based Bortz, Kalos and Labowitch (BKL) algorithm on the Kinetic Monte Carlo method to simulate the physical phenomena. We have found that the island morphology and growth exponent are found to be influenced by substrate anisotropy as well as edge diffusion, however they do not play a significant role in island elongation. The growth exponent and island size distribution are observed to be influenced by substrate anisotropy but are negligibly influenced by edge diffusion. We have found fractal islands when edge diffusion is excluded and compact islands when edge diffusion is included. (author)

  3. Physical growth in children with transfusion-dependent thalassemia

    Directory of Open Access Journals (Sweden)

    Harish K Pemde

    2011-02-01

    Full Text Available Harish K Pemde, Jagdish Chandra, Divya Gupta, Varinder Singh, Rajni Sharma, AK DuttaDepartment of Pediatrics, Lady Hardinge Medical College, Kalawati Saran Children's Hospital, New Delhi, IndiaObjective: To describe physical growth and related factors in transfusion-dependent thalassemia patients.Methods: This is a cross-sectional analysis of the records of the patients registered at and being followed up by the Thalassemia Day Care Center (TDCC at Kalawati Saran Children's Hospital, New Delhi, India. Clinical and laboratory parameters were recorded on a spreadsheet for analysis. Clinical parameters included weight, height, sexual maturity ratings, and general and systemic physical examination. Laboratory parameters included pretransfusion hemoglobin (Hb, periodic serum ferritin, and tests for viral markers of human immunodeficiency virus (HIV and hepatitis B and C. Z-scores for weight, height, and body mass index (BMI were calculated using World Health Organization reference data. Statistical analysis was carried out using Microsoft Excel® and Stata® software.Results: Out of 214 patients registered at the TDCC since 2001, 154 were included in this study. The mean age of patients was 9.19 years (range 0.5–20 years. Pretransfusion Hb was well maintained (mean 9.21 g/dL; 95% confidence interval [CI]: 9.06–9.36, but the mean serum ferritin levels were approximately three times (3112 ng/mL the desired value despite the patients being on deferiprone (72% or deferasirox (25%. One-third (33.11% of the patients had short stature, 13% were thin, and 10.82% were very thin (BMI z-score <-3. No patient was overweight or obese. Linear regression coefficient showed that for every 1-year increase in age, the mean ferritin value increased by 186.21 pg/mL (95% CI: 143.31–228.27. Height z-scores had significant correlation with mean ferritin levels, whereas correlation with mean pretransfusion Hb was not significant statistically. Mean ferritin levels

  4. Efficiency of vibrational sounding in parasitoid host location depends on substrate density.

    Science.gov (United States)

    Fischer, S; Samietz, J; Dorn, S

    2003-10-01

    Parasitoids of concealed hosts have to drill through a substrate with their ovipositor for successful parasitization. Hymenopteran species in this drill-and-sting guild locate immobile pupal hosts by vibrational sounding, i.e., echolocation on solid substrate. Although this host location strategy is assumed to be common among the Orussidae and Ichneumonidae there is no information yet whether it is adapted to characteristics of the host microhabitat. This study examined the effect of substrate density on responsiveness and host location efficiency in two pupal parasitoids, Pimpla turionellae and Xanthopimpla stemmator (Hymenoptera: Ichneumonidae), with different host-niche specialization and corresponding ovipositor morphology. Location and frequency of ovipositor insertions were scored on cylindrical plant stem models of various densities. Substrate density had a significant negative effect on responsiveness, number of ovipositor insertions, and host location precision in both species. The more niche-specific species X. stemmator showed a higher host location precision and insertion activity. We could show that vibrational sounding is obviously adapted to the host microhabitat of the parasitoid species using this host location strategy. We suggest the attenuation of pulses during vibrational sounding as the energetically costly limiting factor for this adaptation.

  5. Spatiotemporal stability of neonatal rat cardiomyocyte monolayers spontaneous activity is dependent on the culture substrate.

    Directory of Open Access Journals (Sweden)

    Jonathan Boudreau-Béland

    Full Text Available In native conditions, cardiac cells must continuously comply with diverse stimuli necessitating a perpetual adaptation. Polydimethylsiloxane (PDMS is commonly used in cell culture to study cellular response to changes in the mechanical environment. The aim of this study was to evaluate the impact of using PDMS substrates on the properties of spontaneous activity of cardiomyocyte monolayer cultures. We compared PDMS to the gold standard normally used in culture: a glass substrate. Although mean frequency of spontaneous activity remained unaltered, incidence of reentrant activity was significantly higher in samples cultured on glass compared to PDMS substrates. Higher spatial and temporal instability of the spontaneous rate activation was found when cardiomyocytes were cultured on PDMS, and correlated with decreased connexin-43 and increased CaV3.1 and HCN2 mRNA levels. Compared to cultures on glass, cultures on PDMS were associated with the strongest response to isoproterenol and acetylcholine. These results reveal the importance of carefully selecting the culture substrate for studies involving mechanical stimulation, especially for tissue engineering or pharmacological high-throughput screening of cardiac tissue analog.

  6. Substrate specificity and pH dependence of homogeneous wheat germ acid phosphatase.

    Science.gov (United States)

    Van Etten, R L; Waymack, P P

    1991-08-01

    The broad substrate specificity of a homogeneous isoenzyme of wheat germ acid phosphatase (WGAP) was extensively investigated by chromatographic, electrophoretic, NMR, and kinetic procedures. WGAP exhibited no divalent metal ion requirement and was unaffected upon incubation with EDTA or o-phenanthroline. A comparison of two catalytically homogeneous isoenzymes revealed little difference in substrate specificity. The specificity of WGAP was established by determining the Michaelis constants for a wide variety of substrates. p-Nitrophenyl phosphate, pyrophosphate, tripolyphosphate, and ATP were preferred substrates while lesser activities were seen toward sugar phosphates, trimetaphosphate, phosphoproteins, and (much less) phosphodiesters. An extensive table of Km and Vmax values is given. The pathway for the hydrolysis of trimetaphosphate was examined by colorimetric and 31P NMR methods and it was found that linear tripolyphosphate is not a free intermediate in the enzymatic reaction. In contrast to literature reports, homogeneous wheat germ acid phosphatase exhibits no measurable carboxylesterase activity, nor does it hydrolyze phenyl phosphonothioate esters or phytic acid at significant rates.

  7. Effects of water depth and substrate color on the growth and body color of the red sea cucumber, Apostichopus japonicus

    Science.gov (United States)

    Jiang, Senhao; Dong, Shuanglin; Gao, Qinfeng; Ren, Yichao; Wang, Fang

    2015-05-01

    Three color variants of the sea cucumber, Apostichopus japonicus are recognized, the red one is highly valued in the market. When the red variant is cultured in ponds in China, its body color changes from red to celadon in 3-6 months. The effects of water depth and substrate color on the growth and body color of this animal were investigated. Juveniles of red A. japonicus were cultured in cages suspended at a range of water depths (20, 50, 100, 150 and 200 cm). The specific growth rate of red sea cucumbers was significantly higher in animals cultured at deeper water layers compared with those grown at shallowers. Body weights were greatest for sea cucumbers cultured at a depth of 150 cm and their survival rates were highest at a depth of 200 cm. A scale to evaluate the color of red sea cucumbers ( R value) was developed using a Pantone standard color card. All stocked animals in the 9-month trial retained a red color, however the red body color was much more intense in sea cucumbers cultured at shallower depths, while animals suspended in deeper layers became pale. In a separate trial, A. japonicus were cultured in suspended cages with seven different colored substrates. Substrate color had a significant effect on the growth and body-color of red A. japonicus. The yield were greatest for A. japonicus cultured on a yellow substrate, followed by green > white > orange > red > black and blue. All sea cucumbers in the 7-month trial retained a red color, although the red was most intense (highest R value) in animals cultured on a blue substrate and pale (lowest R value) for animals cultured on a green substrate.

  8. Epitaxial growth of manganese oxide films on MgAl2O4 (001) substrates and the possible mechanism

    Science.gov (United States)

    Ren, Lizhu; Wu, Shuxiang; Zhou, Wenqi; Li, Shuwei

    2014-03-01

    Three types of manganese oxide films were grown on MgAl2O4 (001) substrates by plasma-assisted molecular beam epitaxy (PA-MBE) under different growth rates and substrate temperatures. The structural characteristics and chemical compositions of the films were investigated by using in-situ reflection high-energy electron diffraction (RHEED), ex-situ X-ray diffraction, Raman, and X-ray photoelectron spectra (XPS). At a lower substrate temperature (730 K), the epitaxial film tends to form mixed phases with a coexistence of Mn3O4 and Mn5O8 in order to relieve the mismatch-strain. However, at a higher substrate temperature (750 K), all of the films crystallize into Mn3O4; the critical thickness of the film grown under a lower growth rate (7 Å/min) is much larger than that under a high growth rate (10 Å/min). When the film reaches a certain critical thickness, the surface will become fairly rough, and another oriented phase Mn3O4 would crystallize on such a surface.

  9. Plasma assisted growth of MoO{sub 3} films on different substrate locations relative to sublimation source

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Rabindar K., E-mail: rkrksharma6@gmail.com; Saini, Sujit K.; Kumar, Prabhat; Singh, Megha; Reddy, G. B. [Thin film laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi – 110016 (India)

    2016-05-06

    In the present paper, we reported the role of substrate locations relative to source on the growth of MoO{sub 3} films deposited on Ni coated glass substrates using plasma assisted sublimation process (PASP). According to the XRD and SEM results, substrate location is very crucial factor to control the morphology of MoO{sub 3} films and the best nanostructure growth (in terms of alignments and features) is obtained in case of Sample B (in which substrate is placed on source). The structural results point out that all films exhibit only orthorhombic phase of molybdenum oxide (i.e. α-MoO{sub 3})but the most preferential growth is recorded in Sample B due to the presence of intense peaks crossponding to only (0 k 0) family of crystal planes (k = 2, 4,6..). The Raman analysis again confirms the orthorhombic nature of MoO{sub 3} NFs and details of vibrational bondsin Sample B have been given in the present report. The MoO{sub 3} NFs show intense PL emission in wavelength range of 300-700 nm with three peaks located at 415, 490, and 523 nm in accordance to the improved crystallinity in Sample B.

  10. Carbon nanotube-based substrates promote cardiogenesis in brown adipose-derived stem cells via β1-integrin-dependent TGF-β1 signaling pathway

    Science.gov (United States)

    Sun, Hongyu; Mou, Yongchao; Li, Yi; Li, Xia; Chen, Zi; Duval, Kayla; Huang, Zhu; Dai, Ruiwu; Tang, Lijun; Tian, Fuzhou

    2016-01-01

    Stem cell-based therapy remains one of the promising approaches for cardiac repair and regeneration. However, its applications are restricted by the limited efficacy of cardiac differentiation. To address this issue, we examined whether carbon nanotubes (CNTs) would provide an instructive extracellular microenvironment to facilitate cardiogenesis in brown adipose-derived stem cells (BASCs) and to elucidate the underlying signaling pathways. In this study, we systematically investigated a series of cellular responses of BASCs due to the incorporation of CNTs into collagen (CNT-Col) substrates that promoted cell adhesion, spreading, and growth. Moreover, we found that CNT-Col substrates remarkably improved the efficiency of BASCs cardiogenesis by using fluorescence staining and quantitative real-time reverse transcription-polymerase chain reaction. Critically, CNTs in the substrates accelerated the maturation of BASCs-derived cardiomyocytes. Furthermore, the underlying mechanism for promotion of BASCs cardiac differentiation by CNTs was determined by immunostaining, quantitative real-time reverse transcription-polymerase chain reaction, and Western blotting assay. It is notable that β1-integrin-dependent TGF-β1 signaling pathway modulates the facilitative effect of CNTs in cardiac differentiation of BASCs. Therefore, it is an efficient approach to regulate cardiac differentiation of BASCs by the incorporation of CNTs into the native matrix. Importantly, our findings can not only facilitate the mechanistic understanding of molecular events initiating cardiac differentiation in stem cells, but also offer a potentially safer source for cardiac regenerative medicine. PMID:27660434

  11. Experimental and simulation study of growth of TiO2 films on different substrates and its applications

    Science.gov (United States)

    Ghogare, Trupti T.; Kartha, Moses J.; Kendre, Subhash D.; Pathan, Habib M.

    2018-04-01

    Monte-Carlo Ballistic Deposition simulations have done on substrates with different initial roughness. The grown films were observed to be porous. The initial growths of the films with seed like initiations are observed for substrate with high initial roughness. In order to confirm this effect TiO2 films were deposited on different substrates using chemical bath deposition. The surface morphological and optical properties were measured using scanning electron microscopy and a UV-Vis spectrophotometer. Flower like porous structure are obtained on glass substrate and continuous porous morphology is formed on ITO substrate. The morphology of the surfaces was successfully reconstructed and the surface porosity was calculated after digitalising images and reconstructed the surfaces. The TiO2 film formed on ITO is observed to be 10% more porous than on the film formed on glass substrate. Diffusion Limited Aggregation simulations with multiple seeds confirms that the observed flower like structure formed are due to the screening effects of the diffusing ion by already deposited particles.

  12. Reynolds-number dependence of turbulence enhancement on collision growth

    Directory of Open Access Journals (Sweden)

    R. Onishi

    2016-10-01

    Full Text Available This study investigates the Reynolds-number dependence of turbulence enhancement on the collision growth of cloud droplets. The Onishi turbulent coagulation kernel proposed in Onishi et al. (2015 is updated by using the direct numerical simulation (DNS results for the Taylor-microscale-based Reynolds number (Reλ up to 1140. The DNS results for particles with a small Stokes number (St show a consistent Reynolds-number dependence of the so-called clustering effect with the locality theory proposed by Onishi et al. (2015. It is confirmed that the present Onishi kernel is more robust for a wider St range and has better agreement with the Reynolds-number dependence shown by the DNS results. The present Onishi kernel is then compared with the Ayala–Wang kernel (Ayala et al., 2008a; Wang et al., 2008. At low and moderate Reynolds numbers, both kernels show similar values except for r2 ∼ r1, for which the Ayala–Wang kernel shows much larger values due to its large turbulence enhancement on collision efficiency. A large difference is observed for the Reynolds-number dependences between the two kernels. The Ayala–Wang kernel increases for the autoconversion region (r1, r2 < 40 µm and for the accretion region (r1 < 40 and r2 > 40 µm; r1 > 40 and r2 < 40 µm as Reλ increases. In contrast, the Onishi kernel decreases for the autoconversion region and increases for the rain–rain self-collection region (r1, r2 > 40 µm. Stochastic collision–coalescence equation (SCE simulations are also conducted to investigate the turbulence enhancement on particle size evolutions. The SCE with the Ayala–Wang kernel (SCE-Ayala and that with the present Onishi kernel (SCE-Onishi are compared with results from the Lagrangian Cloud Simulator (LCS; Onishi et al., 2015, which tracks individual particle motions and size evolutions in homogeneous isotropic turbulence. The SCE-Ayala and SCE-Onishi kernels show consistent

  13. MBE growth and characterization of GaAs1-x Sb x epitaxial layers on Si (0 0 1) substrates

    International Nuclear Information System (INIS)

    Toda, T.; Nishino, F.; Kato, A.; Kambayashi, T.; Jinbo, Y.; Uchitomi, N.

    2006-01-01

    We investigated the growth of GaAs 1- x Sb x (x=1.0, 0.82, 0.69, 0.44, 0.0) layers on Si (0 0 1) substrates using AlSb as a buffer layer. Epilayers were grown as a function of As beam equivalent pressure (BEP) under a constant Sb BEP, and they were then characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), and micro-Raman scattering analysis. We confirmed that GaAs 1- x Sb x layers have been successfully grown on Si substrates by introducing AlSb layers

  14. Layer Dependence and Light Tuning Surface Potential of 2D MoS2 on Various Substrates.

    Science.gov (United States)

    Li, Feng; Qi, Junjie; Xu, Minxuan; Xiao, Jiankun; Xu, Yuliang; Zhang, Xiankun; Liu, Shuo; Zhang, Yue

    2017-04-01

    Here surface potential of chemical vapor deposition (CVD) grown 2D MoS 2 with various layers is reported, and the effect of adherent substrate and light illumination on surface potential of monolayer MoS 2 are investigated. The surface potential of MoS 2 on Si/SiO 2 substrate decreases from 4.93 to 4.84 eV with the increase in the number of layer from 1 to 4 or more. Especially, the surface potentials of monolayer MoS 2 are strongly dependent on its adherent substrate, which are determined to be 4.55, 4.88, 4.93, 5.10, and 5.50 eV on Ag, graphene, Si/SiO 2 , Au, and Pt substrates, respectively. Light irradiation is introduced to tuning the surface potential of monolayer MoS 2 , with the increase in light intensity, the surface potential of MoS 2 on Si/SiO 2 substrate decreases from 4.93 to 4.74 eV, while increases from 5.50 to 5.56 eV on Pt substrate. The I-V curves on vertical of monolayer MoS 2 /Pt heterojunction show the decrease in current with the increase of light intensity, and Schottky barrier height at MoS 2 /Pt junctions increases from 0.302 to 0.342 eV. The changed surface potential can be explained by trapped charges on surface, photoinduced carriers, charge transfer, and local electric field. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Reconstructed ancestral enzymes reveal that negative selection drove the evolution of substrate specificity in ADP-dependent kinases.

    Science.gov (United States)

    Castro-Fernandez, Víctor; Herrera-Morande, Alejandra; Zamora, Ricardo; Merino, Felipe; Gonzalez-Ordenes, Felipe; Padilla-Salinas, Felipe; Pereira, Humberto M; Brandão-Neto, Jose; Garratt, Richard C; Guixe, Victoria

    2017-09-22

    One central goal in molecular evolution is to pinpoint the mechanisms and evolutionary forces that cause an enzyme to change its substrate specificity; however, these processes remain largely unexplored. Using the glycolytic ADP-dependent kinases of archaea, including the orders Thermococcales , Methanosarcinales , and Methanococcales , as a model and employing an approach involving paleoenzymology, evolutionary statistics, and protein structural analysis, we could track changes in substrate specificity during ADP-dependent kinase evolution along with the structural determinants of these changes. To do so, we studied five key resurrected ancestral enzymes as well as their extant counterparts. We found that a major shift in function from a bifunctional ancestor that could phosphorylate either glucose or fructose 6-phosphate (fructose-6-P) as a substrate to a fructose 6-P-specific enzyme was started by a single amino acid substitution resulting in negative selection with a ground-state mode against glucose and a subsequent 1,600-fold change in specificity of the ancestral protein. This change rendered the residual phosphorylation of glucose a promiscuous and physiologically irrelevant activity, highlighting how promiscuity may be an evolutionary vestige of ancestral enzyme activities, which have been eliminated over time. We also could reconstruct the evolutionary history of substrate utilization by using an evolutionary model of discrete binary characters, indicating that substrate uses can be discretely lost or acquired during enzyme evolution. These findings exemplify how negative selection and subtle enzyme changes can lead to major evolutionary shifts in function, which can subsequently generate important adaptive advantages, for example, in improving glycolytic efficiency in Thermococcales . © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  16. Effects of hepatocyte growth factor on glutathione synthesis, growth, and apoptosis is cell density-dependent

    International Nuclear Information System (INIS)

    Yang Heping; Magilnick, Nathaniel; Xia Meng; Lu, Shelly C.

    2008-01-01

    Hepatocyte growth factor (HGF) is a potent hepatocyte mitogen that exerts opposing effects depending on cell density. Glutathione (GSH) is the main non-protein thiol in mammalian cells that modulates growth and apoptosis. We previously showed that GSH level is inversely related to cell density of hepatocytes and is positively related to growth. Our current work examined whether HGF can modulate GSH synthesis in a cell density-dependent manner and how GSH in turn influence HGF's effects. We found HGF treatment of H4IIE cells increased cell GSH levels only under subconfluent density. The increase in cell GSH under low density was due to increased transcription of GSH synthetic enzymes. This correlated with increased protein levels and nuclear binding activities of c-Jun, c-Fos, p65, p50, Nrf1 and Nrf2 to the promoter region of these genes. HGF acts as a mitogen in H4IIE cells under low cell density and protects against tumor necrosis factor α (TNFα)-induced apoptosis by limiting JNK activation. However, HGF is pro-apoptotic under high cell density and exacerbates TNFα-induced apoptosis by potentiating JNK activation. The increase in cell GSH under low cell density allows HGF to exert its full mitogenic effect but is not necessary for its anti-apoptotic effect

  17. Thermal oxidation of seeds for the hydrothermal growth of WO{sub 3} nanorods on ITO glass substrate

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Chai Yan [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Department of Mechanical and Material Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Sungai Long, Bandar Sungai Long, Cheras, 43000 Kajang, Selangor (Malaysia); Abdul Razak, Khairunisak, E-mail: khairunisak@usm.my [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); NanoBiotechnology Research and Innovation (NanoBRI), Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Lockman, Zainovia, E-mail: zainovia@usm.my [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)

    2015-11-30

    This work reports a simple seed formation method for the hydrothermal growth of tungsten oxide (WO{sub 3}) nanorods. A WO{sub 3} seed layer was prepared by thermal oxidation, where a W-sputtered substrate was heated and oxidized in a furnace. Oxidation temperatures and periods were varied at 400–550 °C and 5–60 min, respectively, to determine an appropriate seed layer for nanorod growth. Thermal oxidation at 500 °C for 15 min was found to produce a seed layer with sufficient crystallinity and good adhesion to the substrate. These properties prevented the seed from peeling off during the hydrothermal process, thereby allowing nanorod growth on the seed. The nanorod film showed better electrochromic behavior (higher current density of − 1.11 and + 0.65 mA cm{sup −2}) than compact film (lower current density of − 0.54 and + 0.28 mA cm{sup −2}). - Highlights: • A simple seed formation method (thermal oxidation) on sputtered W film is reported. • Crystalline seed with good adhesion to substrate is required for nanorod growth. • The appropriate temperature and period for seed formation were 500 °C and 15 min. • WO{sub 3} nanorods exhibited higher electrochromic current density than WO{sub 3} compact film.

  18. Temperature dependence of the aggregation behavior of aluminum nanoparticles on liquid substrate

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Qi-Fa; Cheng, Yi; Tao, Xiang-Ming; Yang, Bo [Zhejiang University, Department of Physics (China); Li, Bao-Xing [Hangzhou Normal University, Department of Physics (China); Ye, Gao-Xiang, E-mail: gxye@zju.edu.cn, E-mail: gxye@mail.hz.zj.cn [Zhejiang University, Department of Physics (China)

    2015-03-15

    Aluminum (Al) nanoparticle aggregates have been fabricated by thermal evaporation method on silicone oil surfaces at different substrate temperatures. The average diameter and height of the Al nanoparticles, namely Φ{sub avg} and H{sub avg}, are of the order of 10{sup 1} and 10{sup 0} nm, respectively. As the substrate temperature T{sub s} increases from 293 to 393 K, to the first order of approximation, Φ{sub avg} increases exponentially and H{sub avg} increases quickly between 333 and 373 K. By transmission electron microscopy measurement, we find that the Al nanoparticles and their aggregates exhibit amorphous structure over the whole temperature range. A simple theoretical model is established to explain the coalescence process of the nanoparticles with T{sub s}.

  19. Substrate-Dependent Inhibition of P-glycoprotein Mediated Efflux Transport of Digoxin

    DEFF Research Database (Denmark)

    Saaby, Lasse; Ozgür, Burak; Brodin, Birger

    , distribution and excretion of a wide range of structurally diverse drug compounds and P-gp therefore constitutes a potential site for drug-drug interactions. The U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) recommend that all new investigational drugs be screened...... for interactions with P-gp among other transporters in vitro. This includes an evaluation of new drug compounds as inhibitors of P-gp, preferably in competition with a clinically relevant probe substrate such as digoxin. However, increasing evidence indicates that the binding pocket of P-gp contains several...... overlapping binding sites for substrates. This suggests that drug-drug interactions may be pairwise specific and observations of interaction from a single drug-drug combination may therefore not apply to a second drug combination. At present, it is not known which drug combinations should be considered...

  20. Temperature dependence of the aggregation behavior of aluminum nanoparticles on liquid substrate

    International Nuclear Information System (INIS)

    Pan, Qi-Fa; Cheng, Yi; Tao, Xiang-Ming; Yang, Bo; Li, Bao-Xing; Ye, Gao-Xiang

    2015-01-01

    Aluminum (Al) nanoparticle aggregates have been fabricated by thermal evaporation method on silicone oil surfaces at different substrate temperatures. The average diameter and height of the Al nanoparticles, namely Φ avg and H avg , are of the order of 10 1 and 10 0 nm, respectively. As the substrate temperature T s increases from 293 to 393 K, to the first order of approximation, Φ avg increases exponentially and H avg increases quickly between 333 and 373 K. By transmission electron microscopy measurement, we find that the Al nanoparticles and their aggregates exhibit amorphous structure over the whole temperature range. A simple theoretical model is established to explain the coalescence process of the nanoparticles with T s

  1. Substrate and pH-Dependent Kinetic Profile of 3-Mercaptopropionate Dioxygenase from Pseudomonas aeruginosa.

    Science.gov (United States)

    Fellner, Matthias; Aloi, Sekotilani; Tchesnokov, Egor P; Wilbanks, Sigurd M; Jameson, Guy N L

    2016-03-08

    Thiol dioxygenases catalyze the synthesis of sulfinic acids in a range of organisms from bacteria to mammals. A thiol dioxygenase from the bacterium Pseudomonas aeruginosa oxidizes both 3-mercaptopropionic acid and cysteine, with a ∼70 fold preference for 3-mercaptopropionic acid over all pHs. This substrate reactivity is widened compared to other thiol dioxygenases and was exploited in this investigation of the residues important for activity. A simple model incorporating two protonation events was used to fit profiles of the Michaelis-Menten parameters determined at different pH values for both substrates. The pKs determined using plots of k(cat)/Km differ at low pH, but not in a way easily attributable to protonation of the substrate alone and share a common value at higher pH. Plots of k(cat) versus pH are also quite different at low pH showing the monoprotonated ES complexes with 3-mercaptopropionic acid and cysteine have different pKs. At higher pH, k(cat) decreases sigmoidally with a similar pK regardless of substrate. Loss of reactivity at high pH is attributed to deprotonation of tyrosine 159 and its influence on dioxygen binding. A mechanism is proposed by which deprotonation of tyrosine 159 both blocks oxygen binding and concomitantly promotes cystine formation. Finally, the role of tyrosine 159 was further probed by production of a G95C variant that is able to form a cysteine-tyrosine crosslink homologous to that found in mammalian cysteine dioxygenases. Activity of this variant is severely impaired. Crystallography shows that when un-crosslinked, the cysteine thiol excludes tyrosine 159 from its native position, while kinetic analysis shows that the thioether bond impairs reactivity of the crosslinked form.

  2. Sumo-dependent substrate targeting of the SUMO protease Ulp1

    Directory of Open Access Journals (Sweden)

    Westerbeck Jason W

    2011-10-01

    Full Text Available Abstract Background In the yeast Saccharomyces cerevisiae, the essential small ubiquitin-like modifier (SUMO protease Ulp1 is responsible for both removing SUMO/Smt3 from specific target proteins and for processing precursor SUMO into its conjugation-competent form. Ulp1 localizes predominantly to nuclear pore complexes but has also been shown to deconjugate sumoylated septins at the bud-neck of dividing cells. How Ulp1 is directed to bud-neck localized septins and other cytoplasmic deconjugation targets is not well understood. Results Using a structure/function approach, we set out to elucidate features of Ulp1 that are required for substrate targeting. To aid our studies, we took advantage of a catalytically inactive mutant of Ulp1 that is greatly enriched at the septin ring of dividing yeast cells. We found that the localization of Ulp1 to the septins requires both SUMO and specific structural features of Ulp1's catalytic domain. Our analysis identified a 218-amino acid, substrate-trapping mutant of the catalytic domain of Ulp1, Ulp1(3(C580S, that is necessary and sufficient for septin localization. We also used the targeting and SUMO-binding properties of Ulp1(3(C580S to purify Smt3-modified proteins from cell extracts. Conclusions Our study provides novel insights into how the Ulp1 SUMO protease is actively targeted to its substrates in vivo and in vitro. Furthermore, we found that a substrate-trapping Ulp1(3(C580S interacts robustly with human SUMO1, SUMO2 and SUMO2 chains, making it a potentially useful tool for the analysis and purification of SUMO-modified proteins.

  3. Structural properties, crystal quality and growth modes of MOCVD-grown AlN with TMAl pretreatment of sapphire substrate

    KAUST Repository

    Sun, Haiding; Wu, Feng; Altahtamouni, Talal Mohammed Ahmad; Alfaraj, Nasir; Li, Kun; Detchprohm, Theeradetch; Dupuis, Russell; Li, Xiaohang

    2017-01-01

    The growth of high quality AlN epitaxial films relies on precise control of the initial growth stages. In this work, we examined the influence of the trimethylaluminum (TMAl) pretreatment of sapphire substrates on the structural properties, crystal quality and growth modes of heteroepitaxial AlN films on (0001) sapphire substrates. Without the pretreatment, the AlN films nucleated on the smooth surface but exhibited mixed crystallographic Al- (N-) polarity, resulting in rough AlN film surfaces. With increasing the pretreatment time from 1 to 5 s, the N-polarity started to be impeded. However, small islands were formed on sapphire surface due to the decompostion of TMAl. As a result, small voids became noticeable at the nucleation layer (NL) because the growth started as quasi three-dimensional (3D) but transformed to 2D mode as the film grew thicker and got coalesced, leading to smoother and Al-polar films. On the other hand, longer pretreatment time of 40 s formed large 3D islands on sapphire, and thus initiated a 3D-growth mode of the AlN film, generating Al-polar AlN nanocolumns with different facets, which resulted into rougher film surfaces. The epitaxial growth modes and their correlation with the AlN film crystal quality under different TMAl pretreatments are also discussed.

  4. Structural properties, crystal quality and growth modes of MOCVD-grown AlN with TMAl pretreatment of sapphire substrate

    KAUST Repository

    Sun, Haiding

    2017-08-08

    The growth of high quality AlN epitaxial films relies on precise control of the initial growth stages. In this work, we examined the influence of the trimethylaluminum (TMAl) pretreatment of sapphire substrates on the structural properties, crystal quality and growth modes of heteroepitaxial AlN films on (0001) sapphire substrates. Without the pretreatment, the AlN films nucleated on the smooth surface but exhibited mixed crystallographic Al- (N-) polarity, resulting in rough AlN film surfaces. With increasing the pretreatment time from 1 to 5 s, the N-polarity started to be impeded. However, small islands were formed on sapphire surface due to the decompostion of TMAl. As a result, small voids became noticeable at the nucleation layer (NL) because the growth started as quasi three-dimensional (3D) but transformed to 2D mode as the film grew thicker and got coalesced, leading to smoother and Al-polar films. On the other hand, longer pretreatment time of 40 s formed large 3D islands on sapphire, and thus initiated a 3D-growth mode of the AlN film, generating Al-polar AlN nanocolumns with different facets, which resulted into rougher film surfaces. The epitaxial growth modes and their correlation with the AlN film crystal quality under different TMAl pretreatments are also discussed.

  5. Investigation of growth, structural and electronic properties of V2O3 thin films on selected substrates

    International Nuclear Information System (INIS)

    Nateprov, Alexei

    2006-08-01

    The present work is devoted to the experimental study of the MI transition in V 2 O 3 thin films, grown on different substrates. The main goal of the work was to develop a technology of growth of V 2 O 3 thin films on substrates with different electrical and structural properties (diamond and LiNbO 3 ), designed for specific applications. The structural and electrical properties of the obtained films were characterized in detail with a special focus on their potential applications. The MIT of V 2 O 3 was investigated by SAW using first directly deposited V 2 O 3 thin film onto a LiNbO 3 substrate. (orig.)

  6. Methylene blue improves mitochondrial respiration and decreases oxidative stress in a substrate-dependent manner in diabetic rat hearts.

    Science.gov (United States)

    Duicu, Oana M; Privistirescu, Andreea; Wolf, Adrian; Petruş, Alexandra; Dănilă, Maria D; Raţiu, Corina D; Muntean, Danina M; Sturza, Adrian

    2017-11-01

    Diabetic cardiomyopathy has been systematically associated with compromised mitochondrial energetics and increased generation of reactive oxygen species (ROS) that underlie its progression to heart failure. Methylene blue is a redox drug with reported protective effects mainly on brain mitochondria. The purpose of the present study was to characterize the effects of acute administration of methylene blue on mitochondrial respiration, H 2 O 2 production, and calcium sensitivity in rat heart mitochondria isolated from healthy and 2 months (streptozotocin-induced) diabetic rats. Mitochondrial respiratory function was assessed by high-resolution respirometry. H 2 O 2 production and calcium retention capacity were measured spectrofluorimetrically. The addition of methylene blue (0.1 μmol·L -1 ) elicited an increase in oxygen consumption of mitochondria energized with complex I and II substrates in both normal and diseased mitochondria. Interestingly, methylene blue elicited a significant increase in H 2 O 2 release in the presence of complex I substrates (glutamate and malate), but had an opposite effect in mitochondria energized with complex II substrate (succinate). No changes in the calcium retention capacity of healthy or diabetic mitochondria were found in the presence of methylene blue. In conclusion, in cardiac mitochondria isolated from diabetic and nondiabetic rat hearts, methylene blue improved respiratory function and elicited a dichotomic, substrate-dependent effect on ROS production.

  7. The effect of substrate orientation on the kinetics and thermodynamics of initial oxide-film growth on metals

    Energy Technology Data Exchange (ETDEWEB)

    Reichel, Friederike

    2007-11-19

    This thesis addresses the effect of the parent metal-substrate orientation on the thermodynamics and kinetics of ultra-thin oxide-film growth on bare metals upon their exposure to oxygen gas at low temperatures (up to 650 K). A model description has been developed to predict the thermodynamically stable microstructure of a thin oxide film grown on its bare metal substrate as function of the oxidation conditions and the substrate orientation. For Mg and Ni, the critical oxide-film thickness is less than 1 oxide monolayer and therefore the initial development of an amorphous oxide phase on these metal substrates is unlikely. Finally, for Cu and densely packed Cr and Fe metal surfaces, oxide overgrowth is predicted to proceed by the direct formation and growth of a crystalline oxide phase. Further, polished Al single-crystals with {l_brace}111{r_brace}, {l_brace}100{r_brace} and {l_brace}110{r_brace} surface orientations were introduced in an ultra-high vacuum system for specimen processing and analysis. After surface cleaning and annealing, the bare Al substrates have been oxidized by exposure to pure oxygen gas. During the oxidation, the oxide-film growth kinetics has been established by real-time in-situ spectroscopic ellipsometry. After the oxidation, the oxide-film microstructures were investigated by angle-resolved X-ray photoelectron spectroscopy and low energy electron diffraction. Finally, high-resolution transmission electron microscopic analysis was applied to study the microstructure and morphology of the grown oxide films on an atomic scale. (orig.)

  8. Combining affinity proteomics and network context to identify new phosphatase substrates and adapters in growth pathways.

    Directory of Open Access Journals (Sweden)

    Francesca eSacco

    2014-05-01

    Full Text Available Protein phosphorylation homoeostasis is tightly controlled and pathological conditions are caused by subtle alterations of the cell phosphorylation profile. Altered levels of kinase activities have already been associated to specific diseases. Less is known about the impact of phosphatases, the enzymes that down-regulate phosphorylation by removing the phosphate groups. This is partly due to our poor understanding of the phosphatase-substrate network. Much of phosphatase substrate specificity is not based on intrinsic enzyme specificity with the catalytic pocket recognizing the sequence/structure context of the phosphorylated residue. In addition many phosphatase catalytic subunits do not form a stable complex with their substrates. This makes the inference and validation of phosphatase substrates a non-trivial task. Here, we present a novel approach that builds on the observation that much of phosphatase substrate selection is based on the network of physical interactions linking the phosphatase to the substrate. We first used affinity proteomics coupled to quantitative mass spectrometry to saturate the interactome of eight phosphatases whose down regulations was shown to affect the activation of the RAS-PI#K pathway. By integrating information from functional siRNA with protein interaction information, we develop a strategy that aims at inferring phosphatase physiological substrates. Graph analysis is used to identify protein scaffolds that may link the catalytic subunits to their substrates. By this approach we rediscover several previously described phosphatase substrate interactions and characterize two new protein scaffolds that promote the dephosphorylation of PTPN11 and ERK by DUSP18 and DUSP26 respectively.

  9. Arbuscular Mycorrhiza Improves Substrate Hydraulic Conductivity in the Plant Available Moisture Range Under Root Growth Exclusion.

    Science.gov (United States)

    Bitterlich, Michael; Franken, Philipp; Graefe, Jan

    2018-01-01

    Arbuscular mycorrhizal fungi (AMF) proliferate in soils and are known to affect soil structure. Although their contribution to structure is extensively investigated, the consequences of those processes for soil water extractability and transport has, so far, gained surprisingly little attention. Therefore we asked, whether AMF can affect water retention and unsaturated hydraulic conductivity under exclusion of root ingrowth, in order to minimize plant driven effects. We carried out experiments with tomato inoculated with Rhizoglomus irregulare in a soil substrate with sand and vermiculite that created variation in colonization by mixed pots with wild type (WT) plants and mycorrhiza resistant (RMC) mutants. Sampling cores were introduced and used to assess substrate moisture retention dynamics and modeling of substrate water retention and hydraulic conductivity. AMF reduced the saturated water content and total porosity, but maintained air filled porosity in soil spheres that excluded root ingrowth. The water content between field capacity and the permanent wilting point (6-1500 kPa) was only reduced in mycorrhizal substrates that contained at least one RMC mutant. Plant available water contents correlated positively with soil protein contents. Soil protein contents were highest in pots that possessed the strongest hyphal colonization, but not significantly affected. Substrate conductivity increased up to 50% in colonized substrates in the physiologically important water potential range between 6 and 10 kPa. The improvements in hydraulic conductivity are restricted to substrates where at least one WT plant was available for the fungus, indicating a necessity of a functional symbiosis for this effect. We conclude that functional mycorrhiza alleviates the resistance to water movement through the substrate in substrate areas outside of the root zone.

  10. Determination of Nitrate Reductase Assay Depending on the Microbial Growth

    International Nuclear Information System (INIS)

    El-Kabbany, H.M.

    2012-01-01

    A rapid micro-dilution assay for determination of the antimicrobial susceptibility of different bacterial isolates was developed. This assay is based on the ability of the most of viable organisms to reduce nitrates. The MIC or MBC could be determined by nitrate reductase (NR) only after 30 to 90 min of incubation depending on the behaviour of microbial growth. Bacterial viability is detected by a positive nitrite reduction rather than visible turbidity. The nitrate reduction assay was compared with standard micro-assay using 250 isolates of different taxa against 10 antibiotics belonging to different classes. An excellent agreement of 82.5 % was found between the two methods and only 17.5 % of 1794 trials showed difference in the determined MIC by tow-dilution interval above or below the MIC determined by the turbidimetric method under the same test conditions. However, the nitrate reduction assay was more rapid and sensitive in detecting viable bacteria and so, established an accurate estimate of the minimal inhibitory concentration (MIC) or the minimal bacterial concentration (MBC). The nitrate reduction assay offers the additional advantage that it could be used to determine the MBC without having to subculture the broth. 232 cases of resistance were detected by NR and 4 different media were tested for susceptibility test. The bacterial isolates were exposed to ultra violet (UV) light for different period

  11. Identification of Toxoplasma gondii cAMP dependent protein kinase and its role in the tachyzoite growth.

    Directory of Open Access Journals (Sweden)

    Hitomi Kurokawa

    Full Text Available cAMP-dependent protein kinase (PKA has been implicated in the asexual stage of the Toxoplasma gondii life cycle through assaying the effect of a PKA-specific inhibitor on its growth rate. Since inhibition of the host cell PKA cannot be ruled out, a more precise evaluation of the role of PKA, as well as characterization of the kinase itself, is necessary.The inhibitory effects of two PKA inhibitors, H89, an ATP-competitive chemical inhibitor, and PKI, a substrate-competitive mammalian natural peptide inhibitor, were estimated. In the in vitro kinase assay, the inhibitory effect of PKI on a recombinant T. gondii PKA catalytic subunit (TgPKA-C was weaker compared to that on mammalian PKA-C. In a tachyzoite growth assay, PKI had little effect on the growth of tachyzoites, whereas H89 strongly inhibited it. Moreover, T. gondii PKA regulatory subunit (TgPKA-R-overexpressing tachyzoites showed a significant growth defect.Our data suggest that PKA plays an important role in the growth of tachyzoites, and the inhibitory effect of substrate-competitive inhibitor PKI on T. gondii PKA was low compared to that of the ATP competitive inhibitor H89.

  12. RHEED and EELS study of Pd/Al bimetallic thin film growth on different α-Al 2O 3 substrates

    Science.gov (United States)

    Moroz, V.; Rajs, K.; Mašek, K.

    2002-06-01

    Pd/Al bimetallic thin films were grown by molecular beam epitaxy on single-crystalline α-Al 2O 3(0 0 0 1) and (1 1 2¯ 0) surfaces. Substrate and deposit crystallographic structures and evolution of deposit lattice parameter during the growth were studied by reflection high-energy electron diffraction. The electron energy loss spectroscopy was used as an auxiliary method for chemical analysis. The bimetallic films were prepared by successive deposition of both Pd and Al metals. The structure of Pd and Al deposits in early stages of the growth and its dependence on the preparation conditions were studied. Two phases of Pd clusters covered by Al overlayer have been found. The formation of Al overlayer strongly influenced the lattice parameter of Pd clusters.

  13. Thickness dependent properties of CMR Manganite thin films on lattice mismatched substrates: Distinguishing Strain and Interface Effects

    Science.gov (United States)

    Davidson, Anthony, III; Kolagani, Rajeswari; Bacharova, Ellisaveta; Yong, Grace; Smolyaninova, Vera; Schaefer, David; Mundle, Rajeh

    2007-03-01

    Epitaxial thin films of CMR manganite materials have been known to show thickness dependent electrical and magnetic properties on lattice mismatched substrates. Below a critical thickness, insulator-metal transition is suppressed. These effects have been largely attributed to the role of bi-axial lattice mismatch strain. Our recent results of epitaxial thin films of La0.67Ca0.33MnO3 (LCMO) on two substrates with varying degrees of compressive lattice mismatch indicate that, in addition to the effect of lattice mismatch strain, the thickness dependence of the properties are influenced by other factors possibly related to the nature of the film substrate interface and defects such as twin boundaries. We have compared the properties of LCMO films on (100) oriented LaAlO3 and (001) oriented NdCaAlO4 both of which induce compressive bi-axial strain. Interestingly, the suppression of the insulator-metal transition is less in films on NCAO which has a larger lattice mismatch. We will present results correlating the electrical and magneto transport properties with the structure and morphology of the films.

  14. Epitaxial growth of Si1−xGex alloys and Ge on Si(100) by electron-cyclotron-resonance Ar plasma chemical vapor deposition without substrate heating

    International Nuclear Information System (INIS)

    Ueno, Naofumi; Sakuraba, Masao; Murota, Junichi; Sato, Shigeo

    2014-01-01

    By using electron-cyclotron-resonance (ECR) Ar-plasma chemical vapor deposition (CVD) without substrate heating, the epitaxial growth process of Si 1−x Ge x alloy and Ge films deposited directly on dilute-HF-treated Si(100) was investigated. From the reflection high energy electron diffraction patterns of the deposited Si 1−x Ge x alloy (x = 0.50, 0.75) and Ge films on Si(100), it is confirmed that epitaxial growth can be realized without substrate heating, and that crystallinity degradation at larger film thickness is observed. The X-ray diffraction peak of the epitaxial films reveals the existence of large compressive strain, which is induced by lattice matching with the Si(100) substrate at smaller film thicknesses, as well as strain relaxation behavior at larger film thicknesses. The Ge fraction of Si 1−x Ge x thin film is in good agreement with the normalized GeH 4 partial pressure. The Si 1−x Ge x deposition rate increases with an increase of GeH 4 partial pressure. The GeH 4 partial pressure dependence of partial deposition rates [(Si or Ge fraction) × (Si 1−x Ge x thickness) / (deposition time)] shows that the Si partial deposition rate is slightly enhanced by the existence of Ge. From these results, it is proposed that the ECR-plasma CVD process can be utilized for Ge fraction control in highly-strained heterostructure formation of group IV semiconductors. - Highlights: • Si 1−x Ge x alloy and Ge were epitaxially grown on Si(100) without substrate heating. • Large strain and its relaxation behavior can be observed by X-ray diffraction. • Ge fraction of Si 1−x Ge x is equal to normalized GeH 4 partial pressure. • Si partial deposition rate is slightly enhanced by existence of Ge

  15. Molecular dynamics study of growth and interface structure during aluminum deposition on Ni(1 0 0) substrate

    International Nuclear Information System (INIS)

    er, Laboratory of Radiation and Matter, Faculty of Science and Technology, 26000 Settat (Morocco); Univ Hassan 1er, Laboratory LS3M, Faculté Polydisciplinaire of Khouribga, 26000 Settat (Morocco))" data-affiliation=" (Univ Hassan 1er, Laboratory of Radiation and Matter, Faculty of Science and Technology, 26000 Settat (Morocco); Univ Hassan 1er, Laboratory LS3M, Faculté Polydisciplinaire of Khouribga, 26000 Settat (Morocco))" >Hassani, A.; Makan, A.; er, Laboratory LS3M, Faculté Polydisciplinaire of Khouribga, 26000 Settat (Morocco))" data-affiliation=" (Univ Hassan 1er, Laboratory LS3M, Faculté Polydisciplinaire of Khouribga, 26000 Settat (Morocco))" >Sbiaai, K.; er, Laboratory of Radiation and Matter, Faculty of Science and Technology, 26000 Settat (Morocco))" data-affiliation=" (Univ Hassan 1er, Laboratory of Radiation and Matter, Faculty of Science and Technology, 26000 Settat (Morocco))" >Tabyaoui, A.; er, Laboratory LS3M, Faculté Polydisciplinaire of Khouribga, 26000 Settat (Morocco))" data-affiliation=" (Univ Hassan 1er, Laboratory LS3M, Faculté Polydisciplinaire of Khouribga, 26000 Settat (Morocco))" >Hasnaoui, A.

    2015-01-01

    Highlights: • Aluminum thin film growth on Ni(1 0 0) substrate was investigated. • Molecular dynamics simulation based on EAM interaction potential was considered. • Hexagonal and fourfold structures coexisted in the first layer. • Interface mismatch was revealed by wavy effect occurring in both lateral directions. • Film growth followed a layer-by-layer mode only in the first three deposited layers. - Abstract: We investigate aluminum thin film growth on Ni(1 0 0) substrate by means of molecular dynamics simulation. Embedded Atom Method interaction potential is considered. The simulation is performed at 300 K using an incident energy of 1 eV. The substrate-grown film interface shows the coexistence of hexagonal and fourfold structures in the first layer during the initial stage of deposition. As the deposition proceeds, the hexagonal geometry transforms to fourfold one which becomes dominant toward the end of deposition. The coverage of this layer exceeded 100%. Moreover, the deposited Al atoms with fourfold geometry adopt the lattice parameter of Ni as the thickness of deposited film increases. The interface mismatch investigation revealed that the roughness is dictated by how the Al(1 1 1) fits to the Ni(1 0 0) substrate, which may be reflected by a wavy effect occurring in both lateral directions. Furthermore, the film grows by a layer-by-layer mode with a coverage rate greater than 66.7% in the first three layers, while it follows an island mode with a coverage rate lower than the previous value (66.7%) beyond the third layer. Overall, a detailed analysis of each layer growth has established a relationship between the number of deposited atoms and the coverage rate of each layer

  16. High Momentum Particle Identification Detector The Study of Cesium Iodide Quantum Efficiency Dependency on Substrate Material, Temperature and Quartz Window

    CERN Document Server

    Wisna, Gde Bimananda M

    2014-01-01

    The Cesium Iodide (CsI) is used as a material for detecting Cherenkov radiation produced by high momentum particle in High Momentum Particle Identification Detector (HMPID) at ALICE Experiment at CERN. This work provides investigation and analysis of The Quantum Efficiency (QE) result of CsI which is deposited on five samples substrates such as copper passivated red, copper passivated yellow, aluminium, copper coated with nickel and copper coated with nickel then coated with gold. The measurement of five samples is held under temperature $60^{0}$ C and $25^{0}$ C (room temperature) and also with optical quartz window which can be adjusted to limit the wavelength range which reach the CsI. The result shows there are dependency of substrate, temperature due to enhancement effect and also quartz windows usage on QE of CsI. The results of five samples is then compared and analyzed.

  17. Effect of substrate roughness on growth of diamond by hot filament ...

    Indian Academy of Sciences (India)

    Administrator

    Polycrystalline diamond coatings are grown on Si (100) substrate by hot filament CVD technique. We investigate ... toughness of the film as the crystal changes its phase from monocrystalline to .... is a characteristic of graphite. We mark the.

  18. JORDANIAN ZEOLITIC TUFF AS A RAW MATERIAL FOR THE PREPARATION OF SUBSTRATES USED FOR PLANT GROWTH

    Directory of Open Access Journals (Sweden)

    Ivan Manolov

    2006-07-01

    Full Text Available One of the problems faced in front of industry for potting media is limited amount of quality row materials (mainly peat for unlimited production of quality substrates in the future. The using of natural minerals for production of substrates or as amendments for existing substrates is possible solution for this problem. The natural zeolites with their specific properties – high CEC, high content of macro and microelements are one of good alternatives to the traditional potting media. Each zeolite deposit has unique chemical composition, physical and mechanical properties. That is why obligatory preliminary condition for their successful application in agriculture is caring out of biological study with agricultural plants for determination of the optimal parameters of chemical and physicochemical properties of the substrates.

  19. Growth optimization and characterization of GaN epilayers on multifaceted (111) surfaces etched on Si(100) substrates

    Energy Technology Data Exchange (ETDEWEB)

    Ansah-Antwi, KwaDwo Konadu, E-mail: kakadee@gmail.com; Chua, Soo Jin [Institute of Materials Research and Engineering (IMRE), A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, Innovis # 08-03, Singapore 138634 (Singapore); Department of Electrical and Computer Engineering, National University of Singapore, E4-5-45, 4 Engineering Drive 3, Singapore 117576 (Singapore); Soh, Chew Beng [Singapore Institute of Technology, 10 Dover Drive, Singapore 138683 (Singapore); Liu, Hongfei [Institute of Materials Research and Engineering (IMRE), A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, Innovis # 08-03, Singapore 138634 (Singapore)

    2015-11-15

    The four nearest Si(111) multifaceted sidewalls were exposed inside an array of 3 μm-wide square holes patterned on an Si(100) substrate, and this patterned Si(100) substrate was used as a substrate for the deposition of a gallium nitride (GaN) epilayer. Subsequently the effect that the growth pressure, the etched-hole profiles, and the etched-hole arrangement had upon the quality of the as-grown GaN was investigated. The coalescence of the as-grown GaN epilayer on the exposed Si(111) facets was observed to be enhanced with reduced growth pressure from 120 to 90 Torr. A larger Si(001) plane area at the bottom of the etched holes resulted in bidirectional GaN domains, which resulted in poor material quality. The bidirectional GaN domains were observed as two sets of six peaks via a high-resolution x-ray diffraction phi scan of the GaN(10-11) reflection. It was also shown that a triangular array of etched holes was more desirable than square arrays of etched holes for the growth high-quality and continuous GaN films.

  20. Growth and characterization of semi-polar (11-22) GaN on patterned (113) Si substrates

    International Nuclear Information System (INIS)

    Bai, J; Yu, X; Gong, Y; Hou, Y N; Zhang, Y; Wang, T

    2015-01-01

    Patterned (113) Si substrates have been fabricated for the growth of (11-22) semi-polar GaN, which completely eliminates one of the great issues in the growth of semi-polar GaN on silicon substrates, ‘Ga melting-back’. Furthermore, unlike any other mask patterning approaches which normally lead to parallel grooves along a particular orientation, our approach is to form periodic square window patterns. As a result, crack-free semi-polar (11-22) GaN with a significant improvement in crystal quality has been achieved, in particular, basal stacking faults (BSFs) have been significantly reduced. The mechanism for the defect suppression has been investigated based on detailed transmission electron microscopy measurements. It has been found that the BSFs can be impeded effectively at an early growth stage due to the priority growth along the 〈0001〉 direction. The additional 〈1-100〉 lateral growth above the masks results in a further reduction in dislocation density. The significant reduction in BSFs has been confirmed by low temperature photoluminescence measurements. (paper)

  1. Growth and yield performance of Pleurotus ostreatus (Jacq. Fr.) Kumm (oyster mushroom) on different substrates

    OpenAIRE

    Girmay, Zenebe; Gorems, Weldesemayat; Birhanu, Getachew; Zewdie, Solomon

    2016-01-01

    Mushroom cultivation is reported as an economically viable bio-technology process for conversion of various lignocellulosic wastes. Given the lack of technology know-how on the cultivation of mushroom, this study was conducted in Wondo Genet College of Forestry and Natural Resource, with the aim to assess the suitability of selected substrates (agricultural and/or forest wastes) for oyster mushroom cultivation. Accordingly, four substrates (cotton seed, paper waste, wheat straw, and sawdust) ...

  2. A study of size dependent structure, morphology and luminescence behavior of CdS films on Si substrate

    International Nuclear Information System (INIS)

    Kaushik, Diksha; Singh, Ragini Raj; Sharma, Madhulika; Gupta, D.K.; Lalla, N.P.; Pandey, R.K.

    2007-01-01

    Size tunable cadmium sulfide (CdS) films deposited by a dip coating technique on silicon (100) and indium tin oxide/glass substrates have been characterized using X-ray diffraction, X-ray reflectivity, transmission electron microscopy, atomic force microscopy and photoluminescence spectroscopy. The structural characterization indicated growth of an oriented phase of cadmium sulfide. Transmission electron microscopy used to calculate the particle size indicated narrow size dispersion. The tendency of nanocrystalline CdS films to form ordered clusters of CdS quantum dots on silicon (100) substrate has been revealed by morphological studies using atomic force microscopy. The photoluminescence emission spectroscopy of the cadmium sulfide films has also been investigated. It is shown that the nanocrystalline CdS exhibit intense photoluminescence as compared to the large grained polycrystalline CdS films. The effect of quantum confinement also manifested as a blue shift of photoluminescence emission. It is shown that the observed photoluminescence behavior of CdS is substantially enhanced when the nanocrystallites are assembled on silicon (100) substrate

  3. Size- and phase-dependent mechanical properties of ultrathin Si films on polyimide substrates

    International Nuclear Information System (INIS)

    Schlich, Franziska F.; Spolenak, Ralph

    2016-01-01

    Ultrathin Si films in the nanometer range are extensively used for electronic and optoelectronic devices. Their mechanical properties have a high impact on the durability of the devices during lifetime. Here, fragmentation and buckling of 8–103 nm thin amorphous and polycrystalline (poly-) Si films on polyimide substrates have been studied by in situ light microscopy, Raman spectroscopy and resistance measurements. Generally, a smaller film thickness and a compressive residual stress delays the fracture of the film. The fracture strength of poly-Si films is larger compared to that of amorphous Si films while the adhesion to the substrate is better for amorphous Si compared to poly-Si. The onset delamination as a function of film thickness differs for the two phases and is described by two different models. Thin-film models for fracture toughness (amorphous Si: K 1C  = 1.49 ± 0.22, poly-Si: K 1C  = 3.36 ± 1.37) are applied, discussed, and found to be consistent with literature values.

  4. Temporal, spatial and substrate-dependent variations of Danish hard-bottom macrofauna

    DEFF Research Database (Denmark)

    Dahl, L.; Dahl, K.

    2002-01-01

    Detailed knowledge of the Danish hard-bottom fauna is at present limited because of sampling problems. In this study, two different sampling units were used to yield quantitative results of the fauna on two stone reefs in Kattegat: natural holdfasts of Laminaria digitata and plastic pan-scourers ......Detailed knowledge of the Danish hard-bottom fauna is at present limited because of sampling problems. In this study, two different sampling units were used to yield quantitative results of the fauna on two stone reefs in Kattegat: natural holdfasts of Laminaria digitata and plastic pan...... on the Shannon-Wiener diversity index, and it showed a high degree of spatial and temporal variation. ANOSIM analyses showed a significant difference in species compositions between both sampling location, time and substrate type. The plastic pan-scourers proved to be a valuable substrate for quantitative...... investigations of the fauna. In contrast, the Laminaria holdfasts were too small and variable to be suitable for such studies...

  5. Hepatocyte growth factor regulated tyrosine kinase substrate in the peripheral development and function of B-cells

    International Nuclear Information System (INIS)

    Nagata, Takayuki; Murata, Kazuko; Murata, Ryo; Sun, Shu-lan; Saito, Yutaro; Yamaga, Shuhei; Tanaka, Nobuyuki; Tamai, Keiichi; Moriya, Kunihiko; Kasai, Noriyuki; Sugamura, Kazuo; Ishii, Naoto

    2014-01-01

    Highlights: •ESCRT-0 protein regulates the development of peripheral B-cells. •BCR expression on cell surface should be controlled by the endosomal-sorting system. •Hrs plays important roles in responsiveness to Ag stimulation in B lymphocytes. -- Abstract: Hepatocyte growth factor (HGF)-regulated tyrosine kinase substrate (Hrs) is a vesicular sorting protein that functions as one of the endosomal-sorting proteins required for transport (ESCRT). Hrs, which binds to ubiquitinated proteins through its ubiquitin-interacting motif (UIM), contributes to the lysosomal transport and degradation of ubiquitinated membrane proteins. However, little is known about the relationship between B-cell functions and ESCRT proteins in vivo. Here we examined the immunological roles of Hrs in B-cell development and functions using B-cell-specific Hrs-deficient (Hrs flox/flox ;mb1 cre/+ :Hrs-cKO) mice, which were generated using a cre-LoxP recombination system. Hrs deficiency in B-cells significantly reduced T-cell-dependent antibody production in vivo and impaired the proliferation of B-cells treated in vitro with an anti-IgM monoclonal antibody but not with LPS. Although early development of B-cells in the bone marrow was normal in Hrs-cKO mice, there was a significant decrease in the number of the peripheral transitional B-cells and marginal zone B-cells in the spleen of Hrs-cKO mice. These results indicate that Hrs plays important roles during peripheral development and physiological functions of B lymphocytes

  6. Hepatocyte growth factor regulated tyrosine kinase substrate in the peripheral development and function of B-cells

    Energy Technology Data Exchange (ETDEWEB)

    Nagata, Takayuki [Department of Pharmacy, Iwaki Meisei University, 5-5-1 Chuodai Iino, Iwaki, Fukushima 970-8551 (Japan); Department of Microbiology and Immunology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575 (Japan); Murata, Kazuko, E-mail: murata-k@iwakimu.ac.jp [Department of Pharmacy, Iwaki Meisei University, 5-5-1 Chuodai Iino, Iwaki, Fukushima 970-8551 (Japan); Murata, Ryo [Department of Pharmacy, Iwaki Meisei University, 5-5-1 Chuodai Iino, Iwaki, Fukushima 970-8551 (Japan); Sun, Shu-lan [Department of Microbiology and Immunology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575 (Japan); Saito, Yutaro; Yamaga, Shuhei [Department of Pharmacy, Iwaki Meisei University, 5-5-1 Chuodai Iino, Iwaki, Fukushima 970-8551 (Japan); Tanaka, Nobuyuki; Tamai, Keiichi [Division of Immunology, Miyagi Cancer Research Institute, 47-1 Nodayama, Medeshima-Shiode, Natori 981-1293 (Japan); Moriya, Kunihiko [Department of Pediatrics, Tohoku University School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8575 (Japan); Kasai, Noriyuki [Institute for Animal Experimentation, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575 (Japan); Sugamura, Kazuo [Division of Immunology, Miyagi Cancer Research Institute, 47-1 Nodayama, Medeshima-Shiode, Natori 981-1293 (Japan); Ishii, Naoto [Department of Microbiology and Immunology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575 (Japan)

    2014-01-10

    Highlights: •ESCRT-0 protein regulates the development of peripheral B-cells. •BCR expression on cell surface should be controlled by the endosomal-sorting system. •Hrs plays important roles in responsiveness to Ag stimulation in B lymphocytes. -- Abstract: Hepatocyte growth factor (HGF)-regulated tyrosine kinase substrate (Hrs) is a vesicular sorting protein that functions as one of the endosomal-sorting proteins required for transport (ESCRT). Hrs, which binds to ubiquitinated proteins through its ubiquitin-interacting motif (UIM), contributes to the lysosomal transport and degradation of ubiquitinated membrane proteins. However, little is known about the relationship between B-cell functions and ESCRT proteins in vivo. Here we examined the immunological roles of Hrs in B-cell development and functions using B-cell-specific Hrs-deficient (Hrs{sup flox/flox};mb1{sup cre/+}:Hrs-cKO) mice, which were generated using a cre-LoxP recombination system. Hrs deficiency in B-cells significantly reduced T-cell-dependent antibody production in vivo and impaired the proliferation of B-cells treated in vitro with an anti-IgM monoclonal antibody but not with LPS. Although early development of B-cells in the bone marrow was normal in Hrs-cKO mice, there was a significant decrease in the number of the peripheral transitional B-cells and marginal zone B-cells in the spleen of Hrs-cKO mice. These results indicate that Hrs plays important roles during peripheral development and physiological functions of B lymphocytes.

  7. The role of Aspergillus flavus veA in the production of extracellular proteins during growth on starch substrates.

    Science.gov (United States)

    Duran, Rocio M; Gregersen, Scott; Smith, Timothy D; Bhetariya, Preetida J; Cary, Jeffrey W; Harris-Coward, Pamela Y; Mattison, Christopher P; Grimm, Casey; Calvo, Ana M

    2014-06-01

    The aflatoxin-producer and opportunistic plant pathogenic, filamentous fungus Aspergillus flavus is responsible for the contamination of corn and other important agricultural commodities. In order to obtain nutrients from the host A. flavus produces a variety of extracellular hydrolytic enzymes. Interestingly, A. flavus amylase and protease activity are dependent on the global regulator veA, a gene known to regulate morphogenesis and secondary metabolism in numerous fungi. Analysis of starch degradation by fungal enzymes secreted into broths of starch- or corn kernel-based media showed a notable accumulation of glucose in samples of the A. flavus control strain while the deletion veA sample accumulated high levels of maltose and maltotriose and only a small amount of glucose. Furthermore, SDS-PAGE and proteomics analysis of culture broths from starch- or corn kernel-based media demonstrated differential production of a number of proteins that included a reduction in the amount of a glucoamylase protein in the veA mutant compared to the control strain, while an alpha-amylase was produced in greater quantities in the veA mutant. Quantitative real-time PCR and western blot analyses using anti-glucoamylase or alpha-amylase antisera supported the proteomics results. Additionally, an overall reduction in protease activity was observed in the veA mutant including production of the alkaline protease, oryzin, compared to the control strain. These findings contribute to our knowledge of mechanisms controlling production of hydrolases and other extracellular proteins during growth of A. flavus on natural starch-based substrates.

  8. A model framework to describe growth-linked biodegradation of trace-level pesticides in the presence of coincidental carbon substrates and microbes

    DEFF Research Database (Denmark)

    Liu, Li; Helbling, Damian E.; Kohler, Hans-Peter E.

    2014-01-01

    described were: the growth-linked biodegradation of micropollutant at environmentally relevant concentrations; the effect of coincidental assimilable organic carbon substrates; and the effect of coincidental microbes that compete for assimilable organic carbon substrates. We used Monod kinetic models...... to describe substrate utilization and microbial growth rates for specific pesticide and degrader pairs. We then extended the model to include terms for utilization of assimilable organic carbon substrates by the specific degrader and coincidental microbes, growth on assimilable organic carbon substrates......, challenges remain in developing engineered remediation strategies for pesticide-contaminated environments because the fundamental processes that regulate growth-linked biodegradation of pesticides in natural environments remain poorly understood. In this research, we developed a model framework to describe...

  9. Temperature dependences of growth rates and carrying capacities of marine bacteria depart from metabolic theoretical predictions

    KAUST Repository

    Huete-Stauffer, Tamara Megan

    2015-09-11

    Using the metabolic theory of ecology (MTE) framework, we evaluated over a whole annual cycle the monthly responses to temperature of the growth rates (μ) and carrying capacities (K) of heterotrophic bacterioplankton at a temperate coastal site. We used experimental incubations spanning 6oC with bacterial physiological groups identified by flow cytometry according to membrane integrity (live), nucleic acid content (HNA and LNA) and respiratory activity (CTC+). The temperature dependence of μat the exponential phase of growth was summarized by the activation energy (E), which was variable (-0.52 to 0.72 eV) but followed a seasonal pattern, only reaching the hypothesized value for aerobic heterotrophs of 0.65 eV during the spring bloom for the most active bacterial groups (live, HNA, CTC+). K (i.e. maximum experimental abundance) peaked at 4 × 106 cells mL-1 and generally covaried with μbut, contrary to MTE predictions, it did not decrease consistently with temperature. In the case of live cells, the responses of μand K to temperature were positively correlated and related to seasonal changes in substrate availability, indicating that the responses of bacteria to warming are far from homogeneous and poorly explained by MTE at our site. © FEMS 2015.

  10. Growth and nutritional status of Brazilian wood species Cedrella fissilis and Anadenanthera peregrina in bauxite spoil in response to arbuscular mycorrhizal inoculation and substrate amendment

    Directory of Open Access Journals (Sweden)

    Tótola Marcos Rogério

    2000-01-01

    Full Text Available The growth of Cedrella fissilis Vell. (Cedro Rosa and of Anadenanthera peregrina Benth (Angico Vermelho in bauxite spoil was studied to evaluate their response to substrate amendment or to inoculation with arbuscular mycorrhizal fungi (AMF. The plants were grown in bauxite spoil, topsoil or spoil amended with either topsoil or compost, and inoculated with the AMF Acaulospora scrobiculata, Gigaspora margarita or Glomus etunicatum. Root colonization was highly dependent on the interaction plant-fungus-substrate. In C. fissilis, root colonization by Gigaspora margarita dropped from 75% in bauxite spoil to only 4% in topsoil. Contrarily, root colonization of A. peregrina by the same fungus increased from 48% in spoil to 60% in topsoil. Root colonization of C. fissilis in topsoil was lower than in the three other substrates. The opposite was observed for A. peregrina. Inoculation of the plants with Acaulospora scrobiculata or Glomus etunicatum was very effective in promoting plant growth. Plants of both C. fissilis and A. peregrina did not respond to amendments of bauxite spoil unless they were mycorrhizal. Also, a preferential partitioning of photosynthates to the shoots of A. peregrina inoculated with G. etunicatum or A. scrobiculata, and of C. fissilis inoculated with any of the three species of AMF was observed. C. fissilis showed a greater response to mycorrhizal inoculation than A. peregrina. The mean mycorrhizal efficiency (ME for dry matter production by C. fissilis was 1,847% for A. scrobiculata, 1,922% for G. etunicatum, and 119% for G. margarita. In A. peregrina, the ME was 249% for A. scrobiculata, 540% for G. etunicatum, and 50% for G. margarita. The effect of mycorrhizal inoculation on plant growth seems to be related in part to an enhanced phosphorus absorption by inoculated plants. Moreover, the efficiency with which the absorbed nutrients were used to produce plant biomass was much greater in plants inoculated with A. scrobiculata or

  11. EFFECT OF DIFFERENT SUBSTRATES ON THE GROWTH AND YIELD OF TOMATO (Lycopersicum esculentum Mill UNDER GREENHOUSE CONDITIONS

    Directory of Open Access Journals (Sweden)

    Luis Daniel Ortega-Martínez

    2010-09-01

    Full Text Available The tomato (Lycopersicum esculentum Mill is the world's second most important vegetable. In Mexico, the crop gains economic and social relevance by the generation of foreign exchange and jobs, the production systems of this vegetable have been diversified in order to increase performance, incorporating innovative technologies such as plastic covers, drop irrigation and hydroponics. One of the main factors determining the success of the crop is the substrate, being the medium in which roots were developed which have great influence on the growth and development. In thisstudy, we evaluated during the crop season 2008-2009, the effect of substrate: pine sawdust, compost of sheep manure, agricultural land and red volcanic rock, on growth and yield of tomato. The experimental design used was randomized complete block with four repetitions and ten treatments were evaluated results from a combination of substrates in a volume of 1:1, each experimental unit consisted of four plants, the studied variables were subjected to an analysis of variance (ANOVA using the statistical package Statistical Package for the Social Sciences (SPSS. The genotype used was Sun 7705. Significant differences between substrates, composting with sawdust mixing affected to a greater response for the variables height 4.61 m, 2.1 cm thick of stem, the fruits of greater weight 107.8 g, yield per plant and 4 kg and 25 kg/m-2. However, the number of flowers and clusters was higher in the sawdust substrate, so the composting with sawdust mixture may be a viable option for greenhouse tomato production.

  12. Growth of InGaN multiple quantum wells and GaN eplilayer on GaN substrate

    International Nuclear Information System (INIS)

    Lee, Sung-Nam; Paek, H.S.; Son, J.K.; Sakong, T.; Yoon, E.; Nam, O.H.; Park, Y.

    2006-01-01

    We investigated that the surface morphology of GaN epilayers was significantly affected by the surface tilt orientation of GaN substrate. Surface morphologies of GaN epilayers on GaN substrates show three types: mirror, wavy, and hillock. These surface morphologies are dependent on the surface orientation of GaN substrates. It is found that the hillock morphology of GaN epilayer was formed on the GaN substrate with surface tilt orientation less than 0.1 o . As the surface tilt angle increased to 0.35 o , the surface morphology varied from hillock to wavy morphology. Above a surface tilt angle of 0.4 o , surface morphology changed to the mirror-like type morphology. Additionally, these three types of GaN surface morphology also affected the optical quality of GaN epilayers as well as InGaN multiple quantum wells on GaN substrates by non-uniform In incorporation on the different surface morphologies of GaN epilayers

  13. Study on the Deposition Rate Depending on Substrate Position by Using Ion Beam Sputtering Deposition

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yonggi; Kim, Bomsok; Lee, Jaesang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Ion beams have been used for over thirty years to modify materials in manufacturing of integrated circuits, and improving the corrosion properties of surfaces. Recently, the requirements for ion beam processes are becoming especially challenging in the following areas : ultra shallow junction formation for LSI fabrication, low damage high rate ion beam sputtering and smoothing, high quality functional surface treatment for electrical and optical properties. Ion beam sputtering is an attractive technology for the deposition of thin film coatings onto a broad variety of polymer, Si-wafer, lightweight substrates. Demand for the decoration metal is increasing. In addition, lightweight of parts is important, because of energy issues in the industries. Although a lot of researches have been done with conventional PVD methods for the deposition of metal or ceramic films on the surface of the polymer, there are still adhesion problems.

  14. Substrate-Dependent Differences in the Crystal Structures and Optical Properties of ZnSe Nanowires

    Directory of Open Access Journals (Sweden)

    Keumyoung Seo

    2015-01-01

    Full Text Available The optical and structural properties of ZnSe nanowires directly grown on three different substrates, SiO2, ITO, and graphene, were investigated. ZnSe nanowires grown on graphene and SiO2 were found to have cubic structures, while ZnSe nanowires grown on ITO had a mixed cubic and hexagonal structure. The main peaks in the photoluminescence spectra of ZnSe nanowires grown on SiO2, ITO, and graphene were located at 459, 627, and 627/460 nm, respectively. In addition, a field-emission light-emitting device was fabricated using ZnSe nanowires as a phosphor and graphene as an electrode. The device showed a red emission peak with Commission Internationale de L’Eclairage coordinates of (0.621, 0.315.

  15. Microcrystalline silicon growth by low laser energy crystallization on a plastic substrate

    International Nuclear Information System (INIS)

    Kim, D. Y.; Seo, C. K.; Shim, M. S.; Kim, C. H.; Yi, J.

    2004-01-01

    We are reporting the crystallization of amorphous silicon (a-Si) using a XeCl excimer laser treatment. Although polycarbonate (PC) plastic substrates are very weak at high temperatures of more than 150 .deg. C, they are very useful for applications to microelectronics because of light weight, high transmittance, and flexibility. In order to crystallize a-Si films on plastic substrates, we suggest that a CeO 2 seed layer will be very helpful at a low laser energy density. The seed layer is deposited at room temperature by rf using magnetron sputtering. A seed layer deposition method will be also presented in detail in this article. We compare a-Si crytallization without a seed layer with one with a seed layer deposited between the a-Si and the plastic substrate. The a-Si was deposited on the plastic substrate by using inductively coupled plasma Chemical-Vapor Deposition (ICPCVD) at the room temperature. In this paper, we will present the crystallization properties of a-Si with and without a CeO 2 seed layer on the plastic substrate.

  16. Epitaxial Growth of Permalloy Thin Films on MgO Single-Crystal Substrates

    International Nuclear Information System (INIS)

    Ohtake, Mitsuru; Tanaka, Takahiro; Matsubara, Katsuki; Futamoto, Masaaki; Kirino, Fumiyoshi

    2011-01-01

    Permalloy (Py: Ni - 20 at. % Fe) thin films were prepared on MgO single-crystal substrates of (100), (110), and (111) orientations by molecular beam epitaxy. Py crystals consisting of fcc(100) and hcp(112-bar 0) orientations epitaxially nucleate on MgO(100) substrates. With increasing the substrate temperature, the volume ratio of fcc(100) to hcp(112-bar 0) crystal increases. The metastable hcp(112-bar 0) structure transforms into more stable fcc(110) structure with increasing the film thickness. Py(110) fcc single-crystal films are obtained on MgO(110) substrates, whereas Py films epitaxially grow on MgO(111) substrates with two types of fcc(111) variants whose orientations are rotated around the film normal by 180 deg. each other. X-ray diffraction analysis indicates that the out-of-plane and the in-plane lattice spacings of these fcc-Py films agree within ±0.4% with the values of bulk fcc-Py crystal, suggesting that the strains in the films are very small. High-resolution transmission electron microscopy shows that periodical misfit dislocations are preferentially introduced in the films around the Py/MgO(100) and the Py/MgO(110) interfaces to reduce the lattice mismatches. The magnetic properties are considered to be reflecting the magnetocrystalline anisotropies of bulk fcc-Py and/or metastable hcp-Py crystals and the shape anisotropy caused by the surface undulations.

  17. Epitaxial Growth of Permalloy Thin Films on MgO Single-Crystal Substrates

    Energy Technology Data Exchange (ETDEWEB)

    Ohtake, Mitsuru; Tanaka, Takahiro; Matsubara, Katsuki; Futamoto, Masaaki [Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551 (Japan); Kirino, Fumiyoshi, E-mail: ohtake@futamoto.elect.chuo-u.ac.jp [Graduate School of Fine Arts, Tokyo National University of Fine Arts and Music, 12-8 Ueno-koen, Taito-ku, Tokyo 110-8714 (Japan)

    2011-07-06

    Permalloy (Py: Ni - 20 at. % Fe) thin films were prepared on MgO single-crystal substrates of (100), (110), and (111) orientations by molecular beam epitaxy. Py crystals consisting of fcc(100) and hcp(112-bar 0) orientations epitaxially nucleate on MgO(100) substrates. With increasing the substrate temperature, the volume ratio of fcc(100) to hcp(112-bar 0) crystal increases. The metastable hcp(112-bar 0) structure transforms into more stable fcc(110) structure with increasing the film thickness. Py(110){sub fcc} single-crystal films are obtained on MgO(110) substrates, whereas Py films epitaxially grow on MgO(111) substrates with two types of fcc(111) variants whose orientations are rotated around the film normal by 180 deg. each other. X-ray diffraction analysis indicates that the out-of-plane and the in-plane lattice spacings of these fcc-Py films agree within {+-}0.4% with the values of bulk fcc-Py crystal, suggesting that the strains in the films are very small. High-resolution transmission electron microscopy shows that periodical misfit dislocations are preferentially introduced in the films around the Py/MgO(100) and the Py/MgO(110) interfaces to reduce the lattice mismatches. The magnetic properties are considered to be reflecting the magnetocrystalline anisotropies of bulk fcc-Py and/or metastable hcp-Py crystals and the shape anisotropy caused by the surface undulations.

  18. Coenzyme Q Biosynthesis: Evidence for a Substrate Access Channel in the FAD-Dependent Monooxygenase Coq6.

    Directory of Open Access Journals (Sweden)

    Alexandre Ismail

    2016-01-01

    Full Text Available Coq6 is an enzyme involved in the biosynthesis of coenzyme Q, a polyisoprenylated benzoquinone lipid essential to the function of the mitochondrial respiratory chain. In the yeast Saccharomyces cerevisiae, this putative flavin-dependent monooxygenase is proposed to hydroxylate the benzene ring of coenzyme Q (ubiquinone precursor at position C5. We show here through biochemical studies that Coq6 is a flavoprotein using FAD as a cofactor. Homology models of the Coq6-FAD complex are constructed and studied through molecular dynamics and substrate docking calculations of 3-hexaprenyl-4-hydroxyphenol (4-HP6, a bulky hydrophobic model substrate. We identify a putative access channel for Coq6 in a wild type model and propose in silico mutations positioned at its entrance capable of partially (G248R and L382E single mutations or completely (a G248R-L382E double-mutation blocking access to the channel for the substrate. Further in vivo assays support the computational predictions, thus explaining the decreased activities or inactivation of the mutated enzymes. This work provides the first detailed structural information of an important and highly conserved enzyme of ubiquinone biosynthesis.

  19. Growth hormone-dependent phosphorylation of tyrosine 333 and/or 338 of the growth hormone receptor

    DEFF Research Database (Denmark)

    VanderKuur, J A; Wang, X; Zhang, L

    1995-01-01

    and a reduction of GH-dependent phosphorylation of the full-length receptor. Consistent with Tyr333 and/or Tyr338 serving as substrates of JAK2, these substitutions resulted in a loss of tyrosyl phosphorylation of truncated receptor in an in vitro kinase assay using substantially purified GH.GHR.JAK2 complexes...

  20. Microbial ecology of extreme environments: Antarctic dry valley yeasts and growth in substrate-limited habitats

    Science.gov (United States)

    Vishniac, H. S.

    1982-01-01

    The success of the Antarctic Dry Valley yeasts presumeably results from adaptations to multiple stresses, to low temperatures and substrate-limitation as well as prolonged resting periods enforced by low water availability. Previous investigations have suggested that the crucial stress is substrate limitation. Specific adaptations may be pinpointed by comparing the physiology of the Cryptococcus vishniacii complex, the yeasts of the Tyrol Valley, with their congeners from other habitats. Progress was made in methods of isolation and definition of ecological niches, in the design of experiments in competition for limited substrate, and in establishing the relationships of the Cryptococcus vishniacii complex with other yeasts. In the course of investigating relationships, a new method for 25SrRNA homology was developed. For the first time it appears that 25SrRNA homology may reflect parallel or convergent evolution.

  1. MBE growth and characterization of ZnTe epilayers on m-plane sapphire substrates

    Energy Technology Data Exchange (ETDEWEB)

    Nakasu, Taizo; Sun, Wei-Che; Yamashita, Sotaro; Aiba, Takayuki; Taguri, Kosuke [Department of Electrical Engineering and Bioscience, Waseda University, Tokyo 169-8555 (Japan); Kobayashi, Masakazu [Department of Electrical Engineering and Bioscience, Waseda University, Tokyo 169-8555 (Japan); Kagami Memorial Research Institute for Materials Science and Technology, Waseda University, 2-8-26, Tokyo 169-0051 (Japan); Asahi, Toshiaki [Technology Development Center, JX Nippon Mining and Metals Corporation, Hitachi 317-0056 (Japan); Togo, Hiroyoshi [NTT Microsystem Integration Laboratories, Atsugi 243-0198 (Japan)

    2014-07-15

    ZnTe epilayers were grown on transparent (10-10) oriented (m -plane) sapphire substrates by molecular beam epitaxy (MBE). Pole figure imaging was used to study the domain distribution within the layer. (211)-oriented ZnTe domains were formed on m -plane sapphire. The presence of only one kind of (211) ZnTe domain formed on the 2 -tilted m -plane sapphire substrates was confirmed. Thus, single domain (211) ZnTe epilayers can be grown on the m -plane sapphire using MBE. Although differences in the crystal structure and lattice mismatch are large, precise control of the substrate surface lattice arrangement result in the formation of high-quality epitaxial layers. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Growth of carbon nanotubes by Fe-catalyzed chemical vapor processes on silicon-based substrates

    Science.gov (United States)

    Angelucci, Renato; Rizzoli, Rita; Vinciguerra, Vincenzo; Fortuna Bevilacqua, Maria; Guerri, Sergio; Corticelli, Franco; Passini, Mara

    2007-03-01

    In this paper, a site-selective catalytic chemical vapor deposition synthesis of carbon nanotubes on silicon-based substrates has been developed in order to get horizontally oriented nanotubes for field effect transistors and other electronic devices. Properly micro-fabricated silicon oxide and polysilicon structures have been used as substrates. Iron nanoparticles have been obtained both from a thin Fe film evaporated by e-gun and from iron nitrate solutions accurately dispersed on the substrates. Single-walled nanotubes with diameters as small as 1 nm, bridging polysilicon and silicon dioxide “pillars”, have been grown. The morphology and structure of CNTs have been characterized by SEM, AFM and Raman spectroscopy.

  3. Characterization of TiO2 Thin Films on Glass Substrate Growth Using DC Sputtering Technique

    International Nuclear Information System (INIS)

    Agus Santoso; Tjipto Sujitno; Sayono

    2002-01-01

    It has been fabricated and characterization a TiO 2 thin films deposited on glass substrate using DC sputtering technique. Fabrication of TiO 2 thin films were carried out at electrode voltage 4 kV, sputtering current 5 mA, vacuum pressure 5 x 10 -4 torr, deposition time 150 minutes, and temperature of the substrate were varied from 150 -350 o C, while as a gas sputter was argon. The results was tested their micro structure using SEM, and crystal structure using XRD and found that the crystal structure of TiO 2 powder before deposited on glass substrate was rutile and anatase with orientation (110) and (200) for anatase and (100) and (111) rutile structure. While the crystal structure which deposited at temperature 150 o C and deposition time 2.5 hours was anatase with orientation (001) and (200). (author)

  4. Nickel enhanced graphene growth directly on dielectric substrates by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Wofford, Joseph M., E-mail: joewofford@gmail.com, E-mail: lopes@pdi-berlin.de; Lopes, Joao Marcelo J., E-mail: joewofford@gmail.com, E-mail: lopes@pdi-berlin.de; Riechert, Henning [Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany); Speck, Florian; Seyller, Thomas [Technische Universität Chemnitz, Institut für Physik, Reichenhainer Str. 70, 09126 Chemnitz (Germany)

    2016-07-28

    The efficacy of Ni as a surfactant to improve the crystalline quality of graphene grown directly on dielectric Al{sub 2}O{sub 3}(0001) substrates by molecular beam epitaxy is examined. Simultaneously exposing the substrate to a Ni flux throughout C deposition at 950 °C led to improved charge carrier mobility and a Raman spectrum indicating less structural disorder in the resulting nanocrystalline graphene film. X-ray photoelectron spectroscopy confirmed that no residual Ni could be detected in the film and showed a decrease in the intensity of the defect-related component of the C1s level. Similar improvements were not observed when a lower substrate temperature (850 °C) was used. A close examination of the Raman spectra suggests that Ni reduces the concentration of lattice vacancies in the film, possibly by catalytically assisting adatom incorporation.

  5. Seed-mediated direct growth of CdSe nanoclusters on substrates

    International Nuclear Information System (INIS)

    Pan Shangke; Ebrahim, Shaker; Soliman, Moataz; Qiao Qiquan

    2013-01-01

    Different shapes of CdSe nanostructures were obtained by hydrothermal method with varied Se sources and buffer layers. Hexagonal nanoparticles of CdSe with Wurtzite structure were synthesized from Se powder resource, while CdSe nanoclusters with Wurtzite structure were grown from Na 2 SeO 3 aqueous solution resources at 165 °C using cetyltrimethylammonium bromide as surfactant. Using ZnO nanoparticles as a seed layer, CdSe nanostructures only partially covered the indium tin oxide (ITO) substrates. With ZnO/CdSe quantum dots composite seed layer, CdSe nanostructures fully covered the ITO substrates.

  6. pH Dependence of a Mammalian Polyamine Oxidase: Insights into Substrate Specificity and the Role of Lysine 315†

    Science.gov (United States)

    Pozzi, Michelle Henderson; Gawandi, Vijay; Fitzpatrick, Paul F.

    2009-01-01

    Mammalian polyamine oxidases (PAO) catalyze the oxidation of N1-acetylspermine and N1-acetylspermidine to produce N-acetyl-3-aminopropanaldehyde and spermidine or putrescine. Structurally, PAO is a member of the monoamine oxidase family of flavoproteins. The effects of pH on kinetic parameters of mouse PAO have been determined to provide insight into the protonation state of the polyamine required for catalysis and the roles of ionizable residues in the active site in amine oxidation. For N1-acetylspermine, N1-acetylspermidine, and spermine, the kcat/Kamine-pH profiles are bell-shaped. In each case the profile agrees with that expected if the productive form of the substrate has a single positively charged nitrogen. The pKi-pH profiles for a series of polyamine analogs are most consistent with the nitrogen at the site of oxidation being neutral and one other nitrogen being positively charged in the reactive form of the substrate. With N1-acetylspermine as substrate, the value of kred, the limiting rate constant for flavin reduction, is pH dependent, decreasing below a pKa value of 7.3, again consistent with the requirement for an uncharged nitrogen for substrate oxidation. Lys315 in PAO corresponds to a conserved active site residue found throughout the monoamine oxidase family. Mutation of Lys315 to methionine has no effect on the kcat/Kamine profile for spermine, the kred value with N1-acetylspermine is only 1.8-fold lower in the mutant protein, and the pKa in the kred-pH profile with N1-acetylspermine shifts to 7.8. These results rule out Lys315 as a source of a pKa in the kcat/Kamine or kcat/kred profiles. They also establish that this residue does not play a critical role in amine oxidation by PAO. PMID:19199575

  7. Growth of vertically oriented InN nanorods from In-rich conditions on unintentionally patterned sapphire substrates

    Energy Technology Data Exchange (ETDEWEB)

    Terziyska, Penka T., E-mail: pterziy1@lakeheadu.ca [Semiconductor Research Laboratory, Department of Electrical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, ON P7B 5E1 (Canada); Butcher, Kenneth Scott A. [Semiconductor Research Laboratory, Department of Electrical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, ON P7B 5E1 (Canada); MEAglow Ltd., Box 398, 2400 Nipigon Road, Thunder Bay, ON P7C4W1 (Canada); Rafailov, Peter [Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., 1784 Sofia (Bulgaria); Alexandrov, Dimiter [Semiconductor Research Laboratory, Department of Electrical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, ON P7B 5E1 (Canada); MEAglow Ltd., Box 398, 2400 Nipigon Road, Thunder Bay, ON P7C4W1 (Canada)

    2015-10-30

    Highlights: • Vertical InN nanorods are grown on selective areas of sapphire substrates. • In metal droplets nucleate on the sharp needle apexes on the selective areas. • The preferred orientation and the growth direction of the nanorods are (0 0 0 1). • The nanorods grow from the supersaturated indium melt on their tops. - Abstract: Vertically oriented InN nanorods were grown on selective areas of unintentionally patterned c-oriented sapphire substrates exhibiting sharp needles that preferentially accommodate In-metal liquid droplets, using Migration Enhanced Afterglow (MEAglow) growth technique. We point out that the formation of AlN needles on selected areas can be reproduced intentionally by over-nitridation of unmasked areas of sapphire substrates. The liquid indium droplets serve as a self-catalyst and the nanorods grow from the supersaturated indium melt in the droplet in a vertical direction. X-ray diffraction measurements indicate the presence of hexagonal InN only, with preferred orientation along (0 0 0 1) crystal axis, and very good crystalline quality. The room temperature Raman spectrum shows the presence of the A{sub 1}(TO), E{sub 2}(high) and A{sub 1}(LO) phonon modes of the hexagonal InN.

  8. Epitaxial growth of fcc-CoxNi100-x thin films on MgO(110) single-crystal substrates

    International Nuclear Information System (INIS)

    Ohtake, Mitsuru; Nukaga, Yuri; Sato, Yoichi; Futamoto, Masaaki; Kirino, Fumiyoshi

    2009-01-01

    Co x Ni 100-x (x=100, 80, 20, 0 at. %) epitaxial thin films were prepared on MgO(110) single-crystal substrates heated at 300 deg. C by ultrahigh vacuum molecular beam epitaxy. The growth mechanism is discussed based on lattice strain and crystallographic defects. CoNi(110) single-crystal films with a fcc structure are obtained for all compositions. Co x Ni 100-x film growth follows the Volmer-Weber mode. X-ray diffraction analysis indicates that the out-of-plane and the in-plane lattice spacings of the Co x Ni 100-x films are in agreement within ±0.5% with the values of the respective bulk Co x Ni 100-x crystals, suggesting that the strain in the film is very small. High-resolution cross-sectional transmission microscopy shows that an atomically sharp boundary is formed between a Co(110) fcc film and a MgO(110) substrate, where periodical misfit dislocations are preferentially introduced in the film at the Co/MgO interface. The presence of such periodical misfit dislocations relieves the strain caused by the lattice mismatch between the film and the substrate.

  9. Another brick in the cell wall: biosynthesis dependent growth model.

    Directory of Open Access Journals (Sweden)

    Adelin Barbacci

    Full Text Available Expansive growth of plant cell is conditioned by the cell wall ability to extend irreversibly. This process is possible if (i a tensile stress is developed in the cell wall due to the coupling effect between turgor pressure and the modulation of its mechanical properties through enzymatic and physicochemical reactions and if (ii new cell wall elements can be synthesized and assembled to the existing wall. In other words, expansive growth is the result of coupling effects between mechanical, thermal and chemical energy. To have a better understanding of this process, models must describe the interplay between physical or mechanical variable with biological events. In this paper we propose a general unified and theoretical framework to model growth in function of energy forms and their coupling. This framework is based on irreversible thermodynamics. It is then applied to model growth of the internodal cell of Chara corallina modulated by changes in pressure and temperature. The results describe accurately cell growth in term of length increment but also in term of cell pectate biosynthesis and incorporation to the expanding wall. Moreover, the classical growth model based on Lockhart's equation such as the one proposed by Ortega, appears as a particular and restrictive case of the more general growth equation developed in this paper.

  10. Comparative study of initial growth stage in PVT growth of AlN on SiC and on native AlN substrates

    Energy Technology Data Exchange (ETDEWEB)

    Epelbaum, B.M.; Heimann, P.; Bickermann, M.; Winnacker, A. [Department of Materials Science 6, University of Erlangen-Nuernberg, Martensstr. 7, 91058 Erlangen (Germany)

    2005-05-01

    The main issue in homoepitaxial growth of aluminum nitride (AlN) on native seed substrates appears to be aluminum oxynitride poisoning of seed surface leading to polycrystalline growth at 1750-1850 C. This is well below the lowest growth temperature appropriate for physical vapor transport (PVT) of bulk AlN, which is about 2150 C. Contrary, heteroepitaxial growth of AlN on SiC is relatively easy to achieve because of natural formation of a thin molten layer on the seed surface and VLS growth of AlN via the molten buffer layer. The most critical issue of AlN growth on SiC is cracking of the grown layer upon cooling as a result of different thermal expansion. Optimization of seeded growth process can be achieved by proper choice of SiC seed orientation and by use of ultra-pure starting material. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. Basal metabolic state governs AIF-dependent growth support in pancreatic cancer cells

    International Nuclear Information System (INIS)

    Scott, Andrew J.; Wilkinson, Amanda S.; Wilkinson, John C.

    2016-01-01

    Apoptosis-inducing factor (AIF), named for its involvement in cell death pathways, is a mitochondrial protein that regulates metabolic homeostasis. In addition to supporting the survival of healthy cells, AIF also plays a contributory role to the development of cancer through its enzymatic activity, and we have previously shown that AIF preferentially supports advanced-stage prostate cancer cells. Here we further evaluated the role of AIF in tumorigenesis by exploring its function in pancreatic cancer, a disease setting that most often presents at an advanced stage by the time of diagnosis. A bioinformatics approach was first employed to investigate AIF mRNA transcript levels in pancreatic tumor specimens vs. normal tissues. AIF-deficient pancreatic cancer cell lines were then established via lentiviral infection. Immunoblot analysis was used to determine relative protein quantities within cells. Cell viability was measured by flow cytometry; in vitro and Matrigel™ growth/survival using Coulter™ counting and phase contrast microscopy; and glucose consumption in the absence and presence of Matrigel™ using spectrophotometric methods. Archival gene expression data revealed a modest elevation of AIF transcript levels in subsets of pancreatic tumor specimens, suggesting a possible role in disease progression. AIF expression was then suppressed in a panel of five pancreatic cancer cell lines that display diverse metabolic phenotypes. AIF ablation selectively crippled the growth of cells in vitro in a manner that directly correlated with the loss of mitochondrial respiratory chain subunits and altered glucose metabolism, and these effects were exacerbated in the presence of Matrigel™ substrate. This suggests a critical metabolic role for AIF to pancreatic tumorigenesis, while the spectrum of sensitivities to AIF ablation depends on basal cellular metabolic phenotypes. Altogether these data indicate that AIF supports the growth and survival of metabolically defined

  12. Variation in stonefly (Nemoura cinerea Retzius) growth and development in response to hydraulic and substrate conditions

    NARCIS (Netherlands)

    Franken, R.J.M.; Gardeniers, J.J.P.; Beijer, J.A.J.; Peeters, E.T.H.M.

    2008-01-01

    Spatial heterogeneity among microhabitat patches in aquatic ecosystems creates refuges (e.g., substrate interstices) that protect organisms against a variety of environmental constraints. Aquatic insects have evolved the ability to alter their life-history traits in response to environmental

  13. Growth of Horizonatal ZnO Nanowire Arrays on Any Substrate

    KAUST Repository

    Qin, Yong; Yang, Rusen; Wang, Zhong Lin

    2008-01-01

    A general method is presented for growing laterally aligned and patterned ZnO nanowire (NW) arrays on any substrate as long as it is flat. The orientation control is achieved using the combined effect from ZnO seed layer and the catalytically

  14. Growth of InN films on spinel substrates by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Mitamura, K. [Institute of Industrial Science (IIS), The University of Tokyo, 4-6-1 Komaba, Megruro-ku, Tokyo 153-8505 (Japan); Ohta, J.; Fujioka, H. [Institute of Industrial Science (IIS), The University of Tokyo, 4-6-1 Komaba, Megruro-ku, Tokyo 153-8505 (Japan); Kanagawa Academy of Science and Technology (KAST), 3-2-1 Sakado, Takatsu-ku, Kanagawa 213-0012 (Japan); Oshima, M. [Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2007-10-15

    We have grown InN films on MgAl{sub 2}O{sub 4}(111) substrates with atomically flat surfaces using pulsed laser deposition (PLD) and compared their structural properties with those grown on (Mn,Zn)Fe{sub 2}O{sub 4}(111) substrates. It has been revealed that InN(0001) films grow on MgAl{sub 2}O{sub 4}(111) with an in-plane epitaxial relationship of InN[1 anti 100]//MgAl{sub 2}O{sub 4}[1 anti 10], achieving a lattice mismatch minimum. The InN films exhibited a clear sixfold rotational symmetry, without 30 rotational domains and with a full width at half maximum value of the InN 0002 rocking curve being 17.5 arcmin. Comparison between InN films grown on MgAl{sub 2}O{sub 4} and those on (Mn,Zn)Fe{sub 2}O{sub 4} led us to conclude that suppression of the interfacial reactions between the InN films and the substrate is inherently important to obtain high quality InN on substrates with a spinel structure. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Nitrogen immobilization in plant growth substrates: clean chip residual, pine bark and peat moss

    Science.gov (United States)

    A study was undertaken to determine the extent of nitrogen (N) immobilization and microbial respiration in a high wood-fiber content substrate (clean chip residual (CCR)). Control treatments of pine bark (PB) and peat moss (PM) were compared to two screen sizes (0.95 cm and 0.48 cm) of CCR for micro...

  16. A vanadium-dependent bromoperoxidase in the marine red alga Kappaphycus alvarezii (Doty) Doty displays clear substrate specificity.

    Science.gov (United States)

    Kamenarska, Zornitsa; Taniguchi, Tomokazu; Ohsawa, Noboru; Hiraoka, Masanori; Itoh, Nobuya

    2007-05-01

    Bromoperoxidase activity was initially detected in marine macroalgae belonging to the Solieriaceae family (Gigartinales, Rhodophyta), including Solieria robusta (Greville) Kylin, Eucheuma serra J. Agardh and Kappaphycus alvarezii (Doty) Doty, which are important industrial sources of the polysaccharide carrageenan. Notably, the purification of bromoperoxidase was difficult because due to the coexistence of viscoid polysaccharides. The activity of the partially purified enzyme was dependent on the vanadate ion, and displayed a distinct substrate spectrum from that of previously reported vanadium-dependent bromoperoxidases of marine macroalgae. The enzyme was specific for Br- and I- ions and inactive toward F- and Cl-. The K(m) values for Br- and H2O2 were 2.5x10(-3) M and 8.5x10(-5) M, respectively. The halogenated product, dibromoacetaldehyde, that accumulated in K. alvarezii was additionally determined.

  17. The effect of sulphur-terminated GaAs substrates on the MOVPE growth of CuGaS{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Berndt, P.R. [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa)]. E-mail: pearl.berndt@nmmu.ac.za; Botha, J.R. [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Branch, M.S. [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Leitch, A.W.R. [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Kirmse, H. [Institute of Physics, Chair of Crystallography, Humboldt University of Berlin, Berlin (Germany); Neumann, W. [Institute of Physics, Chair of Crystallography, Humboldt University of Berlin, Berlin (Germany); Weber, J. [Institute for Applied Physics-Semiconductor Physics, University of Technology, Dresden (Germany)

    2007-05-31

    In this study, various CuGaS{sub 2} layers were grown on GaAs (001) substrates using metalorganic vapour phase epitaxy, for the purpose of studying the effect of sulphur-termination of the substrate on layer quality. The resultant films were investigated using X-ray diffractometry, and transmission electron microscopy, with high-resolution transmission electron microscopy providing additional insights into crystallite growth on the control substrates. This paper will demonstrate that sulphur-termination limits substrate degradation. In the absence of sulphur-termination, atypical three-dimensional MOVPE growth is observed, with epitaxial crystallites varying in size from 10 nm to 200 nm. Substrate degradation inhibits lateral growth at the interface resulting in amorphous regions, cavities, and epitaxial crystallites demonstrating overgrowth into mushroom-like structures.

  18. The effect of sulphur-terminated GaAs substrates on the MOVPE growth of CuGaS2 thin films

    International Nuclear Information System (INIS)

    Berndt, P.R.; Botha, J.R.; Branch, M.S.; Leitch, A.W.R.; Kirmse, H.; Neumann, W.; Weber, J.

    2007-01-01

    In this study, various CuGaS 2 layers were grown on GaAs (001) substrates using metalorganic vapour phase epitaxy, for the purpose of studying the effect of sulphur-termination of the substrate on layer quality. The resultant films were investigated using X-ray diffractometry, and transmission electron microscopy, with high-resolution transmission electron microscopy providing additional insights into crystallite growth on the control substrates. This paper will demonstrate that sulphur-termination limits substrate degradation. In the absence of sulphur-termination, atypical three-dimensional MOVPE growth is observed, with epitaxial crystallites varying in size from 10 nm to 200 nm. Substrate degradation inhibits lateral growth at the interface resulting in amorphous regions, cavities, and epitaxial crystallites demonstrating overgrowth into mushroom-like structures

  19. MBE growth of few-layer 2H-MoTe2 on 3D substrates

    Science.gov (United States)

    Vishwanath, Suresh; Sundar, Aditya; Liu, Xinyu; Azcatl, Angelica; Lochocki, Edward; Woll, Arthur R.; Rouvimov, Sergei; Hwang, Wan Sik; Lu, Ning; Peng, Xin; Lien, Huai-Hsun; Weisenberger, John; McDonnell, Stephen; Kim, Moon J.; Dobrowolska, Margaret; Furdyna, Jacek K.; Shen, Kyle; Wallace, Robert M.; Jena, Debdeep; Xing, Huili Grace

    2018-01-01

    MoTe2 is the least explored material in the Molybdenum-chalcogen family. Molecular beam epitaxy (MBE) provides a unique opportunity to tackle the small electronegativity difference between Mo and Te while growing layer by layer away from thermodynamic equilibrium. We find that for a few-layer MoTe2 grown at a moderate rate of ∼6 min per monolayer, a narrow window in temperature (above Te cell temperature) and Te:Mo ratio exists, where we can obtain pure phase 2H-MoTe2. This is confirmed using reflection high-energy electron diffraction (RHEED), Raman spectroscopy and X-ray photoemission spectroscopy (XPS). For growth on CaF2, Grazing incidence X-ray diffraction (GI-XRD) reveals a grain size of ∼90 Å and presence of twinned grains. In this work, we hypothesis the presence of excess Te incorporation in MBE grown few layer 2H-MoTe2. For film on CaF2, it is based on >2 Te:Mo stoichiometry using XPS as well as 'a' and 'c' lattice spacing greater than bulk 2H-MoTe2. On GaAs, its based on observations of Te crystallite formation on film surface, 2 × 2 superstructure observed in RHEED and low energy electron diffraction, larger than bulk c-lattice spacing as well as the lack of electrical conductivity modulation by field effect. Finally, thermal stability and air sensitivity of MBE 2H-MoTe2 is investigated by temperature dependent XRD and XPS, respectively.

  20. Asian outlook: New growth dependent on new productivity | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2018-04-18

    Apr 18, 2018 ... In short, generating new growth will require new productivity. ... Agricultural sector employment levels across the region, though, remain well ... that has created new jobs in construction, manufacturing, trade, and services.

  1. Effects of Growth Hormone and Insulin-Like Growth Factor-1 on Postoperative Muscle and Substrate Metabolism

    Directory of Open Access Journals (Sweden)

    Folke Hammarqvist

    2010-01-01

    To conclude, growth factors influences urea metabolism, protein degradation and protein synthesis. There was no clearcut additional effect when combining GH and IGF-1 but the study was probably underpowered to outrule this and effects on nitrogen balance.

  2. Attempts to lower the detection limits of heavy metals in standardized grass cultures by using alternative growth substrates

    International Nuclear Information System (INIS)

    Winter, A.; Mueller, P.; Wagner, G.

    1992-01-01

    In addition to the use of standardized grass cultures (cf. VDI 3792) within the framework of an effect cadastre, grass cultures were tested on two non-contaminated substrates with nutrient solution in the greenhouse and in the open land during different exposure cycles. The results: As compared to the standard cultures on standardized soil, the cultures have the same or a better growth performance and better dry resistance on the artificial substrates; the blind values and the refore the detection limits in particular for cadmium are by far lower; four-week exposure periods with a two-week overlap have an improved information yield for the same amount of work throughout the investigation period as compared to a two-week exposure. Recommendations are derived from the results for a simplified application of the grass culture method in practice. (orig.) [de

  3. Growth of misfit dislocation-free p/p+ thick epitaxial silicon wafers on Ge-B-codoped substrates

    International Nuclear Information System (INIS)

    Jiang Huihua; Yang Deren; Ma Xiangyang; Tian Daxi; Li Liben; Que Duanlin

    2006-01-01

    The growth of p/p + silicon epitaxial silicon wafers (epi-wafers) without misfit dislocations has been successfully achieved by using heavily boron-doped Czochralski (CZ) silicon wafers codoped with desirable level of germanium as the substrates. The lattice compensation by codoping of germanium and boron into the silicon matrix to reduce the lattice mismatch between the substrate (heavily boron-doped) and epi-layer (lightly boron-doped) is the basic idea underlying in the present achievement. In principle, the codoping of germanium and boron in the CZ silicon can be tailored to achieve misfit dislocation-free epi-layer with required thickness. It is reasonably expected that the presented solution to elimination of misfit dislocations in the p/p + silicon wafers can be applied in the volume production

  4. Catalytic growth of carbon nanofibers on Cr nanoparticles on a carbon substrate: adsorbents for organic dyes in water

    International Nuclear Information System (INIS)

    Alves de Oliveira, Luiz Carlos; Cândido da Silva, Adilson; Rodrigues Teixeira Machado, Alan; Diniz, Renata; César Pereira, Márcio

    2013-01-01

    We have produced carbon nanofibers (CNFs) using leather waste that had been tanned with a chromium bath, and when dried contained Cr 2 O 3 . Suitable reduction processing produced a carbon substrate with supported nanoparticles of chromium metal. Powder X-ray diffraction showed that the Cr 2 O 3 is reduced on the carbon surface to produce CrC and metal Cr, which is the effective catalyst for the CNFs growth. The CNF arrays were confirmed by TEM images. Raman data revealed that the synthesized CNFs have a poor-quality graphite structure which favors their use in adsorption processes. These CNFs presented higher affinity to adsorb anionic dyes, whereas the cationic dyes are better adsorbed on the carbon substrate. The low-cost and availability of the carbon precursor makes their potential use to produce CNFs of interest.

  5. Catalytic growth of carbon nanofibers on Cr nanoparticles on a carbon substrate: adsorbents for organic dyes in water

    Energy Technology Data Exchange (ETDEWEB)

    Alves de Oliveira, Luiz Carlos, E-mail: luizoliveira@qui.ufmg.br; Candido da Silva, Adilson; Rodrigues Teixeira Machado, Alan [ICEx, Universidade Federal de Minas Gerais, Departamento de Quimica (Brazil); Diniz, Renata [Universidade Federal de Juiz de Fora, Departamento de Quimica (Brazil); Cesar Pereira, Marcio [Universidade Federal dos Vales do Jequitinhonha e Mucuri, Instituto de Ciencia, Engenharia e Tecnologia (Brazil)

    2013-05-15

    We have produced carbon nanofibers (CNFs) using leather waste that had been tanned with a chromium bath, and when dried contained Cr{sub 2}O{sub 3}. Suitable reduction processing produced a carbon substrate with supported nanoparticles of chromium metal. Powder X-ray diffraction showed that the Cr{sub 2}O{sub 3} is reduced on the carbon surface to produce CrC and metal Cr, which is the effective catalyst for the CNFs growth. The CNF arrays were confirmed by TEM images. Raman data revealed that the synthesized CNFs have a poor-quality graphite structure which favors their use in adsorption processes. These CNFs presented higher affinity to adsorb anionic dyes, whereas the cationic dyes are better adsorbed on the carbon substrate. The low-cost and availability of the carbon precursor makes their potential use to produce CNFs of interest.

  6. Growth of GaAs-nanowires on GaAs (111)B substrates induced by focused ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Schott, Ruediger; Reuter, Dirk; Wieck, Andreas D. [Lehrstuhl fuer Angewandte Festkoerperphysik, Ruhr-Universitaet Bochum (Germany)

    2011-07-01

    Semiconductor nanowires are a promising system for applications in the areas of electronics and photonics and also for exploring phenomena at the nanoscale. There are several approaches to grow nanowires at arbitrary sites on the wafer. We report about growing GaAs-nanowires on GaAs(111)B substrates via the vapour-liquid-solid (VLS) mechanism in an ultra-high-vacuum (UHV)-cluster of a molecular beam epitaxy (MBE) and a focused ion beam (FIB) system. Our idea is to implant metal seeds (especially Au) for the nanowire growth by in situ patterning using FIB. Due to the UHV transfer between the FIB and the MBE chamber, no further cleaning step of the substrate surface is necessary. Formations of organized GaAs-nanowires and high aspect ratios are observed.

  7. Catalytic growth of carbon nanofibers on Cr nanoparticles on a carbon substrate: adsorbents for organic dyes in water

    Science.gov (United States)

    de Oliveira, Luiz Carlos Alves; da Silva, Adilson Cândido; Machado, Alan Rodrigues Teixeira; Diniz, Renata; Pereira, Márcio César

    2013-05-01

    We have produced carbon nanofibers (CNFs) using leather waste that had been tanned with a chromium bath, and when dried contained Cr2O3. Suitable reduction processing produced a carbon substrate with supported nanoparticles of chromium metal. Powder X-ray diffraction showed that the Cr2O3 is reduced on the carbon surface to produce CrC and metal Cr, which is the effective catalyst for the CNFs growth. The CNF arrays were confirmed by TEM images. Raman data revealed that the synthesized CNFs have a poor-quality graphite structure which favors their use in adsorption processes. These CNFs presented higher affinity to adsorb anionic dyes, whereas the cationic dyes are better adsorbed on the carbon substrate. The low-cost and availability of the carbon precursor makes their potential use to produce CNFs of interest.

  8. Factors influencing epitaxial growth of three-dimensional Ge quantum dot crystals on pit-patterned Si substrate

    International Nuclear Information System (INIS)

    Ma, Y J; Zhong, Z; Yang, X J; Fan, Y L; Jiang, Z M

    2013-01-01

    We investigated the molecular beam epitaxy growth of three-dimensional (3D) Ge quantum dot crystals (QDCs) on periodically pit-patterned Si substrates. A series of factors influencing the growth of QDCs were investigated in detail and the optimized growth conditions were found. The growth of the Si buffer layer and the first quantum dot (QD) layer play a key role in the growth of QDCs. The pit facet inclination angle decreased with increasing buffer layer thickness, and its optimized value was found to be around 21°, ensuring that all the QDs in the first layer nucleate within the pits. A large Ge deposition amount in the first QD layer favors strain build-up by QDs, size uniformity of QDs and hence periodicity of the strain distribution; a thin Si spacer layer favors strain correlation along the growth direction; both effects contribute to the vertical ordering of the QDCs. Results obtained by atomic force microscopy and cross-sectional transmission electron microscopy showed that 3D ordering was achieved in the Ge QDCs with the highest ever areal dot density of 1.2 × 10 10 cm −2 , and that the lateral and the vertical interdot spacing were ∼10 and ∼2.5 nm, respectively. (paper)

  9. Factors influencing epitaxial growth of three-dimensional Ge quantum dot crystals on pit-patterned Si substrate.

    Science.gov (United States)

    Ma, Y J; Zhong, Z; Yang, X J; Fan, Y L; Jiang, Z M

    2013-01-11

    We investigated the molecular beam epitaxy growth of three-dimensional (3D) Ge quantum dot crystals (QDCs) on periodically pit-patterned Si substrates. A series of factors influencing the growth of QDCs were investigated in detail and the optimized growth conditions were found. The growth of the Si buffer layer and the first quantum dot (QD) layer play a key role in the growth of QDCs. The pit facet inclination angle decreased with increasing buffer layer thickness, and its optimized value was found to be around 21°, ensuring that all the QDs in the first layer nucleate within the pits. A large Ge deposition amount in the first QD layer favors strain build-up by QDs, size uniformity of QDs and hence periodicity of the strain distribution; a thin Si spacer layer favors strain correlation along the growth direction; both effects contribute to the vertical ordering of the QDCs. Results obtained by atomic force microscopy and cross-sectional transmission electron microscopy showed that 3D ordering was achieved in the Ge QDCs with the highest ever areal dot density of 1.2 × 10(10) cm(-2), and that the lateral and the vertical interdot spacing were ~10 and ~2.5 nm, respectively.

  10. Substrate dependent reaction channels of the Wolff–Kishner reduction reaction: A theoretical study

    Directory of Open Access Journals (Sweden)

    Shinichi Yamabe

    2014-01-01

    Full Text Available Wolff–Kishner reduction reactions were investigated by DFT calculations for the first time. B3LYP/6-311+G(d,p SCRF=(PCM, solvent = 1,2-ethanediol optimizations were carried out. To investigate the role of the base catalyst, the base-free reaction was examined by the use of acetone, hydrazine (H2N–NH2 and (H2O8. A ready reaction channel of acetone → acetone hydrazine (Me2C=N–NH2 was obtained. The channel involves two likely proton-transfer routes. However, it was found that the base-free reaction was unlikely at the N2 extrusion step from the isopropyl diimine intermediate (Me2C(H–N=N–H. Two base-catalyzed reactions were investigated by models of the ketone, H2N–NH2 and OH−(H2O7. Here, ketones are acetone and acetophenone. While routes of the ketone → hydrazone → diimine are similar, those from the diimines are different. From the isopropyl diimine, the N2 extrusion and the C–H bond formation takes place concomitantly. The concomitance leads to the propane product concertedly. From the (1-phenylethyl substituted diimine, a carbanion intermediate is formed. The para carbon of the phenyl ring of the anion is subject to the protonation, which leads to a 3-ethylidene-1,4-cyclohexadiene intermediate. Its [1,5]-hydrogen migration gives the ethylbenzene product. For both ketone substrates, the diimines undergoing E2 reactions were found to be key intermediates.

  11. Brain substrates of social decision-making in dual diagnosis: cocaine dependence and personality disorders.

    Science.gov (United States)

    Verdejo-Garcia, Antonio; Verdejo-Román, Juan; Albein-Urios, Natalia; Martínez-González, José M; Soriano-Mas, Carles

    2017-03-01

    Cocaine dependence frequently co-occurs with personality disorders, leading to increased interpersonal problems and greater burden of disease. Personality disorders are characterised by patterns of thinking and feeling that divert from social expectations. However, the comorbidity between cocaine dependence and personality disorders has not been substantiated by measures of brain activation during social decision-making. We applied functional magnetic resonance imaging to compare brain activations evoked by a social decision-making task-the Ultimatum Game-in 24 cocaine dependents with personality disorders (CDPD), 19 cocaine dependents without comorbidities and 19 healthy controls. In the Ultimatum Game participants had to accept or reject bids made by another player to split monetary stakes. Offers varied in fairness (in fair offers the proposer shares ~50 percent of the money; in unfair offers the proposer shares <30 percent of the money), and participants were told that if they accept both players get the money, and if they reject both players lose it. We contrasted brain activations during unfair versus fair offers and accept versus reject choices. During evaluation of unfair offers CDPD displayed lower activation in the insula and the anterior cingulate cortex and higher activation in the lateral orbitofrontal cortex and superior frontal and temporal gyri. Frontal activations negatively correlated with emotion recognition. During rejection of offers CDPD displayed lower activation in the anterior cingulate cortex, striatum and midbrain. Dual diagnosis is linked to hypo-activation of the insula and anterior cingulate cortex and hyper-activation of frontal-temporal regions during social decision-making, which associates with poorer emotion recognition. © 2015 Society for the Study of Addiction.

  12. Effects of Growth Hormone and Insulin-Like Growth Factor-1 on Postoperative Muscle and Substrate Metabolism

    OpenAIRE

    Hammarqvist, Folke; Wennström, Ingmar; Wernerman, Jan

    2010-01-01

    This study explored if a combined supplementation of GH and IGF-1 had an additive effect on whole body nitrogen economy, energy, substrate and skeletal muscle metabolism following surgical trauma. Patients were randomized to controls (C; n = 10), to GH (0.15?IU/kg/injection) (GH; n = 7) or GH combined with IGF-1 (40??g/kg/injection) subcutaneously twice a day (GH-IGF-1; n = 9) together with standardized parenteral nutrition. Muscle amino acids, glutathione and the ribosomal pattern reflecting...

  13. Wafer bowing control of free-standing heteroepitaxial diamond (100) films grown on Ir(100) substrates via patterned nucleation growth

    International Nuclear Information System (INIS)

    Yoshikawa, Taro; Kodama, Hideyuki; Kono, Shozo; Suzuki, Kazuhiro; Sawabe, Atsuhito

    2015-01-01

    The potential of patterned nucleation growth (PNG) technique to control the wafer bowing of free-standing heteroepitaxial diamond films was investigated. The heteroepitaxial diamond (100) films were grown on an Ir(100) substrate via PNG technique with different patterns of nucleation regions (NRs), which were dot-arrays with 8 or 13 μm pitch aligned to < 100 > or < 110 > direction of the Ir(100) substrate. The wafer bows and the local stress distributions of the free-standing films were measured using a confocal micro-Raman spectrometer. For each NR pattern, the stress evolutions within the early stage of diamond growth were also studied together with a scanning electron microscopic observation of the coalescing diamond particles. These investigations revealed that the NR pattern, in terms of pitch and direction of dot-array, strongly affects the compressive stress on the nucleation side of the diamond film and dominantly contributes to the elastic deformation of the free-standing film. This indicates that the PNG technique with an appropriate NR pattern is a promising solution to fabricate free-standing heteroepitaxial diamond films with extremely small bows. - Highlights: • Wafer bowing control of free-standing heteroepitaxial diamond (100) films • Effect of patterned nucleation and growth (PNG) technique on wafer bowing reduction • Influence of nucleation region patterns of PNG on wafer bowing • Internal stress analysis of PNG films via confocal micro-Raman spectroscopy

  14. Growth kinetics, effect of carbon substrate in biosynthesis of mcl-PHA by Pseudomonas putida Bet001.

    Science.gov (United States)

    Gumel, A M; Annuar, M S M; Heidelberg, T

    2014-01-01

    Growth associated biosynthesis of medium chain length poly-3-hydroxyalkanoates (mcl-PHA) in Pseudomonas putida Bet001 isolated from palm oil mill effluent was studied. Models with substrate inhibition terms described well the kinetics of its growth. Selected fatty acids (C8:0 to C18:1) and ammonium were used as carbon and nitrogen sources during growth and PHA biosynthesis, resulting in PHA accumulation of about 50 to 69% (w/w) and PHA yields ranging from 10.12 g L(-1) to 15.45 g L(-1), respectively. The monomer composition of the PHA ranges from C4 to C14, and was strongly influenced by the type of carbon substrate fed. Interestingly, an odd carbon chain length (C7) monomer was also detected when C18:1 was fed. Polymer showed melting temperature (T m) of 42.0 (± 0.2) °C, glass transition temperature (T g) of -1.0 (± 0.2) °C and endothermic melting enthalpy of fusion (ΔHf) of 110.3 (± 0.1) J g(-1). The molecular weight (M w) range of the polymer was relatively narrow between 55 to 77 kDa.

  15. Growth kinetics, effect of carbon substrate in biosynthesis of mcl-PHA by Pseudomonas putida Bet001

    Directory of Open Access Journals (Sweden)

    A.M. Gumel

    2014-06-01

    Full Text Available Growth associated biosynthesis of medium chain length poly-3-hydroxyalkanoates (mcl-PHA in Pseudomonas putida Bet001 isolated from palm oil mill effluent was studied. Models with substrate inhibition terms described well the kinetics of its growth. Selected fatty acids (C8:0 to C18:1 and ammonium were used as carbon and nitrogen sources during growth and PHA biosynthesis, resulting in PHA accumulation of about 50 to 69% (w/w and PHA yields ranging from 10.12 g L-1 to 15.45 g L-1, respectively. The monomer composition of the PHA ranges from C4 to C14, and was strongly influenced by the type of carbon substrate fed. Interestingly, an odd carbon chain length (C7 monomer was also detected when C18:1 was fed. Polymer showed melting temperature (Tm of 42.0 (± 0.2 °C, glass transition temperature (Tg of -1.0 (± 0.2 °C and endothermic melting enthalpy of fusion (ΔHf of 110.3 (± 0.1 J g-1. The molecular weight (Mw range of the polymer was relatively narrow between 55 to 77 kDa.

  16. The investigation of alloy formation during InAs nanowires growth on GaAs (111)B substrate

    Energy Technology Data Exchange (ETDEWEB)

    Saqib, Muhammad; Biermanns, Andreas; Davydok, Anton; Pietsch, Ullrich [Festkoerperphysik, Universitaet Siegen, Walter-Flex-Str. 3, Siegen 57072 (Germany); Rieger, Torsten; Grap, Thomas; Lepsa, Mihail [Peter Gruenberg Institute (PGI-9), Forschungzentrum Juelich, Juelich 52425 (Germany)

    2013-07-01

    A possible way to obtain nanowires is the growth in molecular beam epitaxy (MBE) on the (111) oriented surface of the desired substrate, covered by a thin oxide layer. A crucial parameter in this method is the initial thickness of the oxide layer, often determined by an etching procedure. In this contribution, we report on the structural investigation of two different series (etched and unetched) of NWs samples. Vertically aligned InAs nanowires (NWs) doped with Si were self-assisted grown by molecular beam epitaxy on GaAs [111]B substrates covered with a thin SiO{sub x} layer. Using a combination of symmetric and asymmetric X-ray diffraction we study the influence of Si supply on the growth process and nanostructure formation. We find that the number of parasitic crystallites grown between the NWs increases with increasing Si flux. In addition, we observe the formation of a Ga{sub 0.2}In{sub 0.8}As alloy if the growth is performed on samples covered by a defective (etched) oxide layer. This alloy formation is observed within the crystallites and not within the nanowires. The Gallium concentration is determined from the lattice mismatch of the crystallites relative to the InAs nanowires. No alloy formation is found for samples with faultless oxide layers.

  17. Growth of M-plane (10-10)InN on LiAlO2(100) substrate

    International Nuclear Information System (INIS)

    Takagi, Yusuke; Muto, Daisuke; Araki, Tsutomu; Nanishi, Yasushi; Yamaguchi, Tomohiro

    2009-01-01

    In this study, we report the growth and characterization of M-plane InN films on LiAlO 2 (100) substrates by radio-frequency plasma assisted molecular beam epitaxy (RF-MBE). InN films were grown at various temperatures and under various V/III ratios on the substrates. Pure M -plane InN films were successfully grown at a high temperature of 450 C and under a slightly In-rich condition, while the incorporation of C-plane phase was observed in M -plane InN films grown at low temperatures of less than 400 C or under a N-rich condition. These indicate that controls of growth temperature and V/III ratio are important for the growth of pure M-plane InN films. The in-plane epitaxial relationships of M -plane InN on LiAlO 2 (100) were[0001] InN //[010] LiAlO 2 and[1-210] InN //[001] LiAlO 2 . A surface electron accumulation layer on the obtained M-plane InN film is also discussed. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Effects of bamboo substrate and supplemental feeding on growth and production of hybrid red tilapia fingerlings (Oreochromis mossambicusxOrechromis niloticus)

    NARCIS (Netherlands)

    Keshavanath, P.; Gangadhar, B.; Ramesh, T.J.; Dam, van A.A.; Beveridge, M.C.M.; Verdegem, M.C.J.

    2004-01-01

    Periphyton growing on artificial substrates can increase the production of herbivorous fish in aquaculture ponds. Periphyton may be an alternative or a complement for supplemental feed in fingerling production. Growth and production of hybrid red tilapia (Oreochromis mossambicus x Oreochromis

  19. Neuronal nicotinic acetylcholine receptors: Common molecular substrates of nicotine and alcohol dependence

    Directory of Open Access Journals (Sweden)

    Linzy M. Hendrickson

    2013-04-01

    Full Text Available Alcohol and nicotine are often co-abused. As many as 80-95% of alcoholics are also smokers, suggesting that ethanol and nicotine, the primary addictive component of tobacco smoke, may functionally interact in the central nervous system and/or share a common mechanism of action. While nicotine initiates dependence by binding to and activating neuronal nicotinic acetylcholine receptors (nAChRs, ligand-gated cation channels normally activated by endogenous acetylcholine (ACh, ethanol is much less specific with the ability to modulate multiple gene products including those encoding voltage-gated ion channels, and excitatory/inhibitory neurotransmitter receptors. However, emerging data indicate that ethanol interacts with nAChRs, both directly and indirectly, in the mesocorticolimbic dopaminergic (DAergic reward circuitry to affect brain reward systems. Like nicotine, ethanol activates DAergic neurons of the ventral tegmental area (VTA which project to the nucleus accumbens (NAc. Blockade of VTA nAChRs reduces ethanol-mediated activation of DAergic neurons, NAc DA release, consumption, and operant responding for ethanol in rodents. Thus, ethanol may increase ACh release into the VTA driving activation of DAergic neurons through nAChRs. In addition, ethanol potentiates distinct nAChR subtype responses to ACh and nicotine in vitro and in DAergic neurons. The smoking cessation therapeutic and nAChR partial agonist, varenicline, reduces alcohol consumption in heavy drinking smokers and rodent models of alcohol consumption. Finally, single nucleotide polymorphisms in nAChR subunit genes are associated with alcohol dependence phenotypes and smoking behaviors in human populations. Together, results from preclinical, clinical, and genetic studies indicate that nAChRs may have an inherent role in the abusive properties of ethanol, as well as in nicotine and alcohol co-dependence.

  20. Large-area selective CVD epitaxial growth of Ge on Si substrates

    NARCIS (Netherlands)

    Sammak, A.; De Boer, W.; Nanver, L.K.

    2011-01-01

    Selective epitaxial growth of crystalline Ge on Si in a standard ASM Epsilon 2000 CVD reactor is investigated for the fabrication of Ge p+n diodes. At the deposition temperature of 700?C, most of the lattice mismatch-defects are trapped within first 300nm of Ge growth and good quality single crystal

  1. Substrates of Mauritia flexuosa and wastewater from pig farming on growth and quality in seedlings of Acacia mangium

    Directory of Open Access Journals (Sweden)

    Emanuel França Araújo

    Full Text Available ABSTRACT Sustainable alternatives should be adopted to minimise the negative environmental impacts of agricultural activities. The use of wastewater as well as organic waste, from agricultural activities or found naturally, such as the decomposed stems of the Buriti palm (Mauritia flexuosa, can be a sustainable alternative in the production of seedlings for the reforestation of areas in the process of degradation or desertification, common in the State of Piauí, Brazil. The aim of this study was to evaluate growth and quality in seedlings of Acacia mangium Willd grown in substrates with different proportions of decomposed stems of Mauritia flexuosa (DSB, and irrigated with wastewater from pig farming (WPF. The experimental design was completely randomised, arranged in a 5 x 2 factorial scheme, corresponding to five proportions of DSB and soil (v/v,% - 0:100, 20:80, 40:60, 60:40, 80:20, and two sources of irrigation water (well water and WPF, with four replications. At 100 days after sowing (DAS, the seedlings were collected to measure the variables related to growth, quality and nodulation. Height, root collar diameter, shoot dry weight, leaf area and nitrogen accumulation in the shoots were significantly influenced (p≤0.05 by the interaction between substrate and source of irrigation water. The WPF had no significant influence on the growth or quality of the Acacia mangium Willd seedlings. The best ratio between DSB substrate and soil was 46:54, considered the most suitable for seedling production in Acacia mangium Willd.

  2. Growth of Ca2MnO4 Ruddlesden-Popper structured thin films using combinatorial substrate epitaxy

    International Nuclear Information System (INIS)

    Lacotte, M.; David, A.; Pravarthana, D.; Prellier, W.; Grygiel, C.; Rohrer, G. S.; Salvador, P. A.; Velazquez, M.; Kloe, R. de

    2014-01-01

    The local epitaxial growth of pulsed laser deposited Ca 2 MnO 4 films on polycrystalline spark plasma sintered Sr 2 TiO 4 substrates was investigated to determine phase formation and preferred epitaxial orientation relationships (ORs) for isostructural Ruddlesden-Popper (RP) heteroepitaxy, further developing the high-throughput synthetic approach called Combinatorial Substrate Epitaxy (CSE). Both grazing incidence X-ray diffraction and electron backscatter diffraction patterns of the film and substrate were indexable as single-phase RP-structured compounds. The optimal growth temperature (between 650 °C and 800 °C) was found to be 750 °C using the maximum value of the average image quality of the backscattered diffraction patterns. Films grew in a grain-over-grain pattern such that each Ca 2 MnO 4 grain had a single OR with the Sr 2 TiO 4 grain on which it grew. Three primary ORs described 47 out of 49 grain pairs that covered nearly all of RP orientation space. The first OR, found for 20 of the 49, was the expected RP unit-cell over RP unit-cell OR, expressed as [100][001] film ||[100][001] sub . The other two ORs were essentially rotated from the first by 90°, with one (observed for 17 of 49 pairs) being rotated about the [100] and the other (observed for 10 of 49 pairs) being rotated about the [110] (and not exactly by 90°). These results indicate that only a small number of ORs are needed to describe isostructural RP heteroepitaxy and further demonstrate the potential of CSE in the design and growth of a wide range of complex functional oxides

  3. Growth and characterization of indium tin oxide thin films deposited on PET substrates

    International Nuclear Information System (INIS)

    Lee, Jaehyeong; Jung, Hakkee; Lee, Jongin; Lim, Donggun; Yang, Keajoon; Yi, Junsin; Song, Woo-Chang

    2008-01-01

    Transparent and conductive indium tin oxide (ITO) thin films were deposited onto polyethylene terephthalate (PET) by d.c. magnetron sputtering as the front and back electrical contact for applications in flexible displays and optoelectronic devices. In addition, ITO powder was used for sputter target in order to reduce the cost and time of the film formation processes. As the sputtering power and pressure increased, the electrical conductivity of ITO films decreased. The films were increasingly dark gray colored as the sputtering power increased, resulting in the loss of transmittance of the films. When the pressure during deposition was higher, however, the optical transmittance improved at visible region of light. ITO films deposited onto PET have shown similar optical transmittance and electrical resistivity, in comparison with films onto glass substrate. High quality films with resistivity as low as 2.5 x 10 -3 Ω cm and transmittance over 80% have been obtained on to PET substrate by suitably controlling the deposition parameters

  4. Direct growth and patterning of multilayer graphene onto a targeted substrate without an external carbon source.

    Science.gov (United States)

    Kang, Dongseok; Kim, Won-Jun; Lim, Jung Ah; Song, Yong-Won

    2012-07-25

    Using only a simple tube furnace, we demonstrate the synthesis of patterned graphene directly on a designed substrate without the need for an external carbon source. Carbon atoms are absorbed onto Ni evaporator sources as impurities, and incorporated into catalyst layers during the deposition. Heat treatment conditions were optimized so that the atoms diffused out along the grain boundaries to form nanocrystals at the catalyst-substrate interfaces. Graphene patterns were obtained under patterned catalysts, which restricted graphene formation to within patterned areas. The resultant multilayer graphene was characterized by Raman spectroscopy and transmission electron microscopy to verify the high crystallinity and two-dimensional nanomorphology. Finally, a metal-semiconductor diode with a catalyst-graphene contact structure were fabricated and characterized to assess the semiconducting properties of the graphene sheets with respect to the display of asymmetric current-voltage behavior.

  5. Direct evidence of strain transfer for InAs island growth on compliant Si substrates

    Energy Technology Data Exchange (ETDEWEB)

    Marçal, L. A. B.; Magalhães-Paniago, R.; Malachias, Angelo, E-mail: angeloms@fisica.ufmg.br [Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, CEP 31270-901, Belo Horizonte (Brazil); Richard, M.-I. [European Synchrotron (ESRF), ID01 beamline, CS 40220, 38043 Grenoble Cedex 9 (France); Aix-Marseille University, IM2NP-CNRS, Faculté des Sciences de St Jérôme, 13397 Marseille (France); Cavallo, F. [Center for High Technology Materials, University of New Mexico, 1313 Goddard St., Albuquerque, New Mexico 87106 (United States); University of Wisconsin-Madison, 1500 Engineering Drive, Madison, Wisconsin 53706 (United States); Lagally, M. G. [University of Wisconsin-Madison, 1500 Engineering Drive, Madison, Wisconsin 53706 (United States); Schmidt, O. G. [Institute for Integrative Nanosciences, IFW-Dresden, D-01171 Dresden (Germany); Schülli, T. Ü. [European Synchrotron (ESRF), ID01 beamline, CS 40220, 38043 Grenoble Cedex 9 (France); Deneke, Ch. [Laboratório Nacional de Nanotecnologia (LNNano/CNPEM), C.P. 6192, CEP 13083-970, Campinas (Brazil)

    2015-04-13

    Semiconductor heteroepitaxy on top of thin compliant layers has been explored as a path to make inorganic electronics mechanically flexible as well as to integrate materials that cannot be grown directly on rigid substrates. Here, we show direct evidences of strain transfer for InAs islands on freestanding Si thin films (7 nm). Synchrotron X-ray diffraction measurements using a beam size of 300 × 700 nm{sup 2} can directly probe the strain status of the compliant substrate underneath deposited islands. Using a recently developed diffraction mapping technique, three-dimensional reciprocal space maps were reconstructed around the Si (004) peak for specific illuminated positions of the sample. The strain retrieved was analyzed using continuous elasticity theory via Finite-element simulations. The comparison of experiment and simulations yields the amount of strain from the InAs islands, which is transferred to the compliant Si thin film.

  6. Selective growth of vertically aligned Fe-filled carbon nanotubes on oxidized silicon substrates

    Energy Technology Data Exchange (ETDEWEB)

    Moench, I; Kozhuharova-Koseva, R; Ruemmeli, M; Elefant, D; Gemming, T; Kaltofen, R; Leonhardt, A; Schaefer, T; Buechner, B [Leibniz Institute of Solid State and Materials Research Dresden (IFW Dresden), Helmholtzstr. 20, D-01069 Dresden (Germany)

    2007-04-15

    Vertically aligned Fe-filled multi-wall carbon nanotubes (MWNTs) have been grown selectively on the SiO{sub 2} surfaces of patterned amorphous carbon (a-C)/SiO{sub 2}/Si substrates. Their morphology, structure and magnetic properties have been studied. The a-C patterns were prepared using conventional lithography processes combined with a sputter-deposition of a-C (thickness of 100 nm). The aligned Fe-filled MWNTs were produced by pyrolysis of ferrocene in a CVD reactor with a two zone furnace system and have high filling yield. The encapsulated Fe nanowires grown on the SiO{sub 2} structures of the patterned a-C/SiO{sub 2}/Si substrates have diameters of 10-20 nm and can reach a few micrometers in length. The described method enables the preparation of complex architectures of Fe-filled MWNTs and may be used for future applications based on filled nanotubes.

  7. Influence of synthesis parameters on CCVD growth of vertically aligned carbon nanotubes over aluminum substrate.

    Science.gov (United States)

    Szabó, Anna; Kecsenovity, Egon; Pápa, Zsuzsanna; Gyulavári, Tamás; Németh, Krisztián; Horvath, Endre; Hernadi, Klara

    2017-08-25

    In the past two decades, important results have been achieved in the field of carbon nanotube (CNT) research, which revealed that carbon nanotubes have extremely good electrical and mechanical properties The range of applications widens more, if CNTs form a forest-like, vertically aligned structure (VACNT) Although, VACNT-conductive substrate structure could be very advantageous for various applications, to produce proper system without barrier films i.e. with good electrical contact is still a challenge. The aim of the current work is to develop a cheap and easy method for growing carbon nanotubes forests on conductive substrate with the CCVD (Catalytic Chemical Vapor Deposition) technique at 640 °C. The applied catalyst contained Fe and Co and was deposited via dip coating onto an aluminum substrate. In order to control the height of CNT forest several parameters were varied during the both catalyst layer fabrication (e.g. ink concentration, ink composition, dipping speed) and the CCVD synthesis (e.g. gas feeds, reaction time). As-prepared CNT forests were investigated with various methods such as scanning electron microscopy, Raman spectroscopy, and cyclic voltammetry. With such an easy process it was possible to tune both the height and the quality of carbon nanotube forests.

  8. Nitrogen Immobilization in Plant Growth Substrates: Clean Chip Residual, Pine Bark, and Peatmoss

    Directory of Open Access Journals (Sweden)

    Cheryl R. Boyer

    2012-01-01

    Full Text Available Rising costs of potting substrates have caused horticultural growers to search for alternative, lower-cost materials. Objectives of this study were to determine the extent of nitrogen immobilization and microbial respiration in a high wood-fiber content substrate, clean chip residual. Microbial activity and nitrogen availability of two screen sizes (0.95 cm and 0.48 cm of clean chip residual were compared to control treatments of pine bark and peatmoss in a 60-day incubation experiment. Four rates (0, 1, 2, or 3 mg of supplemental nitrogen were assessed. Peatmoss displayed little microbial respiration over the course of the study, regardless of nitrogen rate; followed by pine bark, 0.95 cm clean chip residual, and 0.48 cm clean chip residual. Respiration increased with increasing nitrogen. Total inorganic nitrogen (plant available nitrogen was greatest with peatmoss; inorganic nitrogen in other treatments were similar at the 0, 1, and 2 mg supplemental nitrogen rates, while an increase occurred with the highest rate (3 mg. Clean chip residual and pine bark were similar in available nitrogen compared to peatmoss. This study suggests that nitrogen immobilization in substrates composed of clean chip residual is similar to pine bark and can be treated with similar fertilizer amendments during nursery production.

  9. Growth hormone, interferon-gamma, and leukemia inhibitory factor utilize insulin receptor substrate-2 in intracellular signaling

    DEFF Research Database (Denmark)

    Argetsinger, L S; Norstedt, G; Billestrup, Nils

    1996-01-01

    In this report, we demonstrate that insulin receptor substrate-2 (IRS-2) is tyrosyl-phosphorylated following stimulation of 3T3-F442A fibroblasts with growth hormone (GH), leukemia inhibitory factor and interferon-gamma. In response to GH and leukemia inhibitory factor, IRS-2 is immediately...... for GH is further demonstrated by the finding that GH stimulates association of IRS-2 with the 85-kDa regulatory subunit of phosphatidylinositol 3'-kinase and with the protein-tyrosine phosphatase SHP2. These results are consistent with the possibility that IRS-2 is a downstream signaling partner...

  10. Growth and phycocyanin synthesis in the heterotrophic microalga Galdieria sulphuraria on substrates made of food waste from restaurants and bakeries

    DEFF Research Database (Denmark)

    Sloth, Jenni K; Jensen, Henriette Casper; Pleissner, Daniel

    2017-01-01

    Galdieria sulphuraria 074G (Rhodophyta) was grown heterotrophically in defined medium and on amylolytic and proteolytic hydrolysed food waste from restaurants and bakeries. Substrate uptake, growth, and phycocyanin content were quantified in the cultures. The alga utilised carbohydrates and amino...... in quantities resulting in glucose concentrations of 10 and 50 g L−1 for bakery and restaurant waste, respectively. Still, G. sulphuraria 074G grew and produced phycocyanin efficiently on food waste under adequate conditions and may potentially be utilised for synthesise of high-valuable products from food...

  11. Epitaxial growth of cubic Gd{sub 2}O{sub 3} thin films on Ge substrates

    Energy Technology Data Exchange (ETDEWEB)

    Molle, A; Wiemer, C; Bhuiyan, M D N K; Tallarida, G; Fanciulli, M [CNR-INFM, Laboratorio Nazionale MDM, via C. Olivetti 2, I-20041 Agrate Brianza (Italy)], E-mail: alessandro.molle@mdm.infm.it

    2008-03-15

    Gd{sub 2}O{sub 3} thin films were grown on Ge (001) substrates by molecular beam epitaxy. The epitaxial character of the film is demonstrated by electron diffraction during the growth. The structural characterization of the films shows that the Gd{sub 2}O{sub 3} forms a bixbyite polymorph with a (110) out-of-plane orientation. The formation of bixbyite structured Gd{sub 2}O{sub 3} is discussed in terms of the atomic arrangement of the oxide planes on the Ge(001) surface.

  12. Enhanced growth of highly lattice-mismatched CdSe on GaAs substrates by molecular beam epitaxy

    International Nuclear Information System (INIS)

    Wang, Jyh-Shyang; Tsai, Yu-Hsuan; Wang, Hsiao-Hua; Ke, Han-Xiang; Tong, Shih-Chang; Yang, Chu-Shou; Wu, Chih-Hung; Shen, Ji-Lin

    2013-01-01

    This work demonstrates the improvement of the molecular beam epitaxial growth of zinc-blende CdSe on (0 0 1) GaAs substrate with a large lattice mismatch by introducing a small amount of Te atoms. Exposing the growing surface to Te atoms changes the reflection high-energy electron diffraction pattern from spotty to streaky together with (2 × 1) surface reconstruction, and greatly reduces the full width at half maximum of the X-ray rocking curve and increases the integral intensity of room-temperature photoluminescence by a factor of about nine.

  13. The limitations of seedling growth and drought tolerance to novel soil substrates in arid systems: Implications for restoration success

    Science.gov (United States)

    Bateman, Amber; Lewandrowski, Wolfgang; Stevens, Jason; Muñoz-Rojas, Miriam

    2016-04-01

    Introduction With the limited knowledge available regarding the impact of drought on seedling growth, an understanding of seedling tolerance to arid conditions is crucial for restoration success (James et al., 2013; Muñoz-Rojas et al., 2014). However, restoration in semi-arid areas faces the challenge of re-establishing plant communities on altered soil substrates (Muñoz-Rojas et al., 2015). These substrates are a result of anthropogenic disturbances such as mining which have altered the plant-soil-water dynamics of the ecosystem (Machado et al., 2013). The aim of this study was to assess the impact of mining on the plant-soil-water dynamics of an arid ecosystem of Western Australia (Pilbara region, North Western Australia) and the implications these altered relationships have on seedling growth and their responses to drought. Methods Drought responses of native plant species were assessed through a series of glasshouse experiments. Firstly, 21 species dominant to the Pilbara region were subjected to drought in a topsoil growth media to assess variation in responses (leaf water potential at the time of stomatal closure) across species and identify traits associated with drought tolerance. Secondly, four species ranging in their drought tolerance identified previously, were grown to two leaf stages (second and fourth leaf stage) in three mining substrates (topsoil, a topsoil and waste mix and waste) to assess seedling drought responses to various potential restoration substrates and how that varied with plant development stage. Results and discussion Four morphological traits were found to be significantly associated with drought indicators (leaf mass ratio, stem area, stem length, stem weight), however, these were weak correlations. Waste substrate and its addition to topsoil reduced plant total biomass but did not alter species responses to drought. However, the soil physical properties of the waste reduced water retention and water availability for plant uptake

  14. The influence of substrate source on the growth of Ralstonia eutropha, aiming at the production of polyhydroxyalkanoate

    Directory of Open Access Journals (Sweden)

    Marangoni C.

    2001-01-01

    Full Text Available With the aim of producing polyhydroxyalkanoates, a study of the influence of culture conditions (nitrogen and carbon sources and temperature on the growth of Ralstonia eutropha in stirred flasks was carried out and the use of some low-cost sources (hydrolyzed lactose, inverted sugar and corn steep liquor as evaluated. The best specific growth rate was obtained when inverted sugar was utilized as the substrate (mumax = 0.26 h-1. Two different phases in the assimilation of the carbon source were observed when hydrolyzed lactose was present, suggesting the assimilation first of glucose and then of galactose. To confirm the growth of Ralstonia eutropha using galactose as the only carbon source, experiments were carried out and the results showed that this bacterium is able to grow in the presence of this sugar at a growth rate of 0.13 h-1. The use of galactose by Ralstonia eutropha for its growth has not been reported in the literature until now. Corn steep liquor was found to be a viable alternative nitrogen source to ammonium sulfate. The results of experiments carried out at 30°C and 34°C were similar.

  15. Reducing the substrate dependent scanner leveling effect in low-k1 contact printing

    Science.gov (United States)

    Chang, C. S.; Tseng, C. F.; Huang, C. H.; Yang, Elvis; Yang, T. H.; Chen, K. C.

    2015-03-01

    As the scaling down of design rule for high-density memory device, the small depth of focus (DoF) budget may be deteriorated by focus leveling errors, which arises in unpredicted reflectivity from multilayer structures on the topographic wafer. The leveling sensors of ASML scanner use near infrared (NIR) range wavelength which can penetrate through most of films using in semiconductor fabrication such as photo-resist, bottom anti reflective coating (BARC) and dielectric materials. Consequently, the reflected light from underlying substructures would disturb leveling sensors from accurate leveling. The different pattern densities and layout characteristics between array and periphery of a memory chip are expected to result in different leveling signals. Furthermore, the process dependent variations between wafer central and edge areas are also considered to yield different leveling performances during wafer exposure. In this study, lower blind contact immunity was observed for peripheral contacts comparing to the array contacts especially around wafer edge region. In order to overcome this problem, a series of investigations have been carried out. The wafer edge leveling optimization through circuit dependent focus edge clearance (CDFEC) option doesn't get improvement. Air gauge improved process leveling (AGILE) function of ASML immersion scanner doesn't show improved result either. The ILD uniformity improvement and step height treatments around wafer edge such as edge exclusion of film deposition and bevel etching are also ineffective to mitigate the blind contact problem of peripheral patterns. Altering the etch hard-mask stack is finally found to be an effective approach to alleviate the issue. For instance, through either containing high temperature deposition advanced patterning film (APF) in the hard-mask or inserting higher opaque film such as amorphous Si in between the hard-mask stack.

  16. Regulation of AKT phosphorylation at Ser473 and Thr308 by endoplasmic reticulum stress modulates substrate specificity in a severity dependent manner.

    Directory of Open Access Journals (Sweden)

    Hong Wa Yung

    2011-03-01

    Full Text Available Endoplasmic reticulum (ER stress is a common factor in the pathophysiology of diverse human diseases that are characterised by contrasting cellular behaviours, from proliferation in cancer to apoptosis in neurodegenerative disorders. Coincidently, dysregulation of AKT/PKB activity, which is the central regulator of cell growth, proliferation and survival, is often associated with the same diseases. Here, we demonstrate that ER stress modulates AKT substrate specificity in a severity-dependent manner, as shown by phospho-specific antibodies against known AKT targets. ER stress also reduces both total and phosphorylated AKT in a severity-dependent manner, without affecting activity of the upstream kinase PDK1. Normalisation to total AKT revealed that under ER stress phosphorylation of Thr308 is suppressed while that of Ser473 is increased. ER stress induces GRP78, and siRNA-mediated knock-down of GRP78 enhances phosphorylation at Ser473 by 3.6 fold, but not at Thr308. Substrate specificity is again altered. An in-situ proximity ligation assay revealed a physical interaction between GRP78 and AKT at the plasma membrane of cells following induction of ER stress. Staining was weak in cells with normal nuclear morphology but stronger in those displaying rounded, condensed nuclei. Co-immunoprecipitation of GRP78 and P-AKT(Ser473 confirmed the immuno-complex consists of non-phosphorylated AKT (Ser473 and Thr308. The interaction is likely specific as AKT did not bind to all molecular chaperones, and GRP78 did not bind to p70 S6 kinase. These findings provide one mechanistic explanation for how ER stress contributes to human pathologies demonstrating contrasting cell fates via modulation of AKT signalling.

  17. Regulation of AKT Phosphorylation at Ser473 and Thr308 by Endoplasmic Reticulum Stress Modulates Substrate Specificity in a Severity Dependent Manner

    Science.gov (United States)

    Yung, Hong Wa

    2011-01-01

    Endoplasmic reticulum (ER) stress is a common factor in the pathophysiology of diverse human diseases that are characterised by contrasting cellular behaviours, from proliferation in cancer to apoptosis in neurodegenerative disorders. Coincidently, dysregulation of AKT/PKB activity, which is the central regulator of cell growth, proliferation and survival, is often associated with the same diseases. Here, we demonstrate that ER stress modulates AKT substrate specificity in a severity-dependent manner, as shown by phospho-specific antibodies against known AKT targets. ER stress also reduces both total and phosphorylated AKT in a severity-dependent manner, without affecting activity of the upstream kinase PDK1. Normalisation to total AKT revealed that under ER stress phosphorylation of Thr308 is suppressed while that of Ser473 is increased. ER stress induces GRP78, and siRNA-mediated knock-down of GRP78 enhances phosphorylation at Ser473 by 3.6 fold, but not at Thr308. Substrate specificity is again altered. An in-situ proximity ligation assay revealed a physical interaction between GRP78 and AKT at the plasma membrane of cells following induction of ER stress. Staining was weak in cells with normal nuclear morphology but stronger in those displaying rounded, condensed nuclei. Co-immunoprecipitation of GRP78 and P-AKT(Ser473) confirmed the immuno-complex consists of non-phosphorylated AKT (Ser473 and Thr308). The interaction is likely specific as AKT did not bind to all molecular chaperones, and GRP78 did not bind to p70 S6 kinase. These findings provide one mechanistic explanation for how ER stress contributes to human pathologies demonstrating contrasting cell fates via modulation of AKT signalling. PMID:21445305

  18. Perversities of Extreme Dependence and Unequal Growth in the TAR

    NARCIS (Netherlands)

    A.M. Fischer (Andrew Martín)

    2007-01-01

    textabstractThe official Chinese press recently came out with a series of articles reporting the latest statistics on the phenomenally rapid economic growth that has been taking place in the Tibet Autonomous Region (TAR) since the mid-1990s through sheer force of Central Government subsidies.

  19. Density-dependent growth and metamorphosis in the larval bronze ...

    Indian Academy of Sciences (India)

    Effects of density and kinship on growth and metamorphosis in tadpoles of Rana temporalis were studied in a 2 × 4 factorial experiment. Fifteen egg masses were collected from streams in the Western Ghat region of south India. The tadpoles were raised as siblings or in groups of non-siblings at increasing density levels, viz ...

  20. Growth orientation dependent photoluminescence of GaAsN alloys

    International Nuclear Information System (INIS)

    Han, Xiuxun; Tanaka, Tomohiro; Kojima, Nobuaki; Ohshita, Yoshio; Yamaguchi, Masafumi; Sato, Shinichiro

    2012-01-01

    We report photoluminescence (PL) studies of both as-grown and electron-irradiated GaAsN epilayers on (311)A/B and (100) GaAs substrates. A long room-temperature (RT) PL lifetime, as well as an enhanced N incorporation, is observed in (311)B GaAsN epilayers as compared with (311)A and (100) samples. There is no direct correlation between the RT PL lifetime and the emission intensity from Ga vacancy complex detected at low temperature. The lifetime damage coefficient is relatively low for (311)B GaAsN. The irradiation-induced nonradiative recombination defects are suggested to be N- and/or As-related according to a geometrical analysis based on the tetrahedral coordination of GaAsN crystal.

  1. Dependence on the growth direction of the strain in AlGaSb alloys

    Energy Technology Data Exchange (ETDEWEB)

    Rojas-Lopez, M; Delgado-Macuil, R; Gayou, V L; Orduna-Diaz, A [CIBA-Tlaxcala, IPN, Tlaxcala, Tlax. (Mexico); Momox-Beristain, E [FC-BUAP, Puebla, Pue. (Mexico); Salazar-Hernandez, B [CIICAp-UAEM, Cuernavaca, Mor. (Mexico); Rodriguez, A G, E-mail: marlonrl@yahoo.com.m [IICO-UASLP, San Luis Potosi, S.L.P. (Mexico)

    2009-05-01

    High resolution x-ray diffraction profiles were obtained from Al{sub x}Ga{sub 1-x}Sb layers grown on (001) and (111) GaSb substrates. The out of plane lattice parameter, was estimated directly from the symmetrical diffractions for (001) and (111) alloys. These results show that all the layers are strained, and those grown on (001) GaSb are slightly more strained than the corresponding layers grown on (111) GaSb. This difference is explained by the dependence of the strain ratio on growth direction. The out of plane lattice parameter as a function of Al content is higher than the corresponding bulk lattice parameter of Al{sub x}Ga{sub 1-x}Sb layers obtained with Vegard's law. Also, the perpendicular and the in-plane lattice parameter expected for pseudomorphic alloys, was estimated from the strain ratios, assuming an elastic deformation and using the EDX alloy composition to interpolate the elastic constants C{sub ij}. This estimation also shows that almost all the layers are fully strained.

  2. Composition and growth procedure-dependent properties of electrodeposited CuInSe 2 thin films

    Science.gov (United States)

    Babu, S. Moorthy; Ennaoui, A.; Lux-Steiner, M. Ch.

    2005-02-01

    CuInSe 2 thin films were deposited on molybdenum-coated glass substrates by electrodeposition. Deposition was carried out with a variety of electrochemical bath compositions. The quality of the deposits depends very much on the source materials as well as the concentration of the same in the electrolyte. The deposition potential was varied from -0.4 to -0.75 V vs. SCE. The pH of the solution was adjusted to 1.5-2 using diluted sulphuric acid. Chloride salts containing bath yield good surface morphology, but there is always excess of the metallic content in the deposited films. Different growth procedures, like initial metallic layers of copper or indium, layers of copper selenide or indium selenide before the actual deposition of ternary chalcopyrite layers were attempted. Fabrication pathway, morphological and compositional changes due to the different precursor route has been analysed. The quality of the deposits prepared by one-step electrodeposition is better than the deposits with a two-stage process. The deposited films were characterized with XRD, SEM-EDAX, UV-visible spectroscopy and I- V characteristics. The deposited films were annealed in air as well as in nitrogen atmosphere. The influence of annealing temperature, environment and annealing time on the properties of the films are evaluated. Attempts were made to fabricate solar cell structure from the deposited absorber films. The structure of Mo/CuInSe 2/CdS/ZnO/Ni was characterized with surface, optical and electrical studies.

  3. Frank-ter Haar syndrome protein Tks4 regulates epidermal growth factor-dependent cell migration.

    Science.gov (United States)

    Bögel, Gábor; Gujdár, Annamária; Geiszt, Miklós; Lányi, Árpád; Fekete, Anna; Sipeki, Szabolcs; Downward, Julian; Buday, László

    2012-09-07

    Mutations in the SH3PXD2B gene coding for the Tks4 protein are responsible for the autosomal recessive Frank-ter Haar syndrome. Tks4, a substrate of Src tyrosine kinase, is implicated in the regulation of podosome formation. Here, we report a novel role for Tks4 in the EGF signaling pathway. In EGF-treated cells, Tks4 is tyrosine-phosphorylated and associated with the activated EGF receptor. This association is not direct but requires the presence of Src tyrosine kinase. In addition, treatment of cells with LY294002, an inhibitor of PI 3-kinase, or mutations of the PX domain reduces tyrosine phosphorylation and membrane translocation of Tks4. Furthermore, a PX domain mutant (R43W) Tks4 carrying a reported point mutation in a Frank-ter Haar syndrome patient showed aberrant intracellular expression and reduced phosphoinositide binding. Finally, silencing of Tks4 was shown to markedly inhibit HeLa cell migration in a Boyden chamber assay in response to EGF or serum. Our results therefore reveal a new function for Tks4 in the regulation of growth factor-dependent cell migration.

  4. Gold nanoparticle growth control - Implementing novel wet chemistry method on silicon substrate

    KAUST Repository

    Al-Ameer, Ammar; Katsiev, Habib; Sinatra, Lutfan; Hussein, Irshad; Bakr, Osman

    2013-01-01

    Controlling particle size, shape, nucleation, and self-assembly on surfaces are some of the main challenges facing electronic device fabrication. In this work, growth of gold nanoparticles over a wide range of sizes was investigated by using a novel

  5. Relationships between stem CO2 efflux, substrate supply, and growth in young loblolly pine trees

    Science.gov (United States)

    Chris A. Maier; Kurt H. Johnsen; Barton D. Clinton; Kim H. Ludovici

    2009-01-01

    We examined the relationships between stem CO2 efflux (Es), diametergrowth, and nonstructural carbohydrate concentration in loblolly pine trees. Carbohydratesupply was altered via stem girdling during rapid stem growth in the

  6. Epitaxial growth of silicon and germanium on (100-oriented crystalline substrates by RF PECVD at 175 °C

    Directory of Open Access Journals (Sweden)

    Mauguin O.

    2012-11-01

    Full Text Available We report on the epitaxial growth of crystalline Si and Ge thin films by standard radio frequency plasma enhanced chemical vapor deposition at 175 °C on (100-oriented silicon substrates. We also demonstrate the epitaxial growth of silicon films on epitaxially grown germanium layers so that multilayer samples sustaining epitaxy could be produced. We used spectroscopic ellipsometry, Raman spectroscopy, transmission electron microscopy and X-ray diffraction to characterize the structure of the films (amorphous, crystalline. These techniques were found to provide consistent results and provided information on the crystallinity and constraints in such lattice-mismatched structures. These results open the way to multiple quantum-well structures, which have been so far limited to few techniques such as Molecular Beam Epitaxy or MetalOrganic Chemical Vapor Deposition.

  7. Influence of AlGaN Buffer Growth Temperature on GaN Epilayer based on Si(lll) Substrate

    International Nuclear Information System (INIS)

    Wei Meng; Wang Xiaoliang; Pan Xu; Xiao Hongling; Wang Cuimei; Zhang Minglan; Wang Zhanguo

    2011-01-01

    This paper investigated the influence of AlGaN buffer growth temperature on strain status and crystal quality of the GaN film on Si(111) sbustrates by metal organic chemical vapor deposition. It was demonstrated by the optical microscopy that AlGaN buffer gorwth temperature had a remarkable effect on compensating tensil stress in top GaN layer and preventing the formation of cracks. X-ray diffraction and atomic force microscopy analysis showed crystal quality and surface morphology of the GaN epilayer could be improved through increasing AlGaN buffer growth temperature. 1μm crack-free GaN epilayer on Si (111) substrates was obtained with graded AlGaN buffer layer at optimized temperature of 1050 deg. C. Transmission electron microscopy analysis revealed that a significant reduction in threading dislocations was achieved in GaN epilayer.

  8. Effect of substrate material on the growth and field emission characteristics of large-area carbon nanotube forests

    Energy Technology Data Exchange (ETDEWEB)

    Ummethala, Raghunandan; Täschner, Christine; Leonhardt, Albrecht; Büchner, Bernd [IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Wenger, Daniela; Tedde, Sandro F. [Siemens Healthcare GmbH, Technology Centre, Guenther-Scharowsky-Strasse 1, 91058 Erlangen (Germany); Eckert, Jürgen [Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, Jahnstrasse 12, A-8700 Leoben (Austria); Department Materials Physics, Montanuniversität Leoben, Jahnstraße 12, A-8700 Leoben (Austria)

    2016-01-28

    Carbon nanotubes (CNTs) are a promising replacement for tungsten filaments as electron emitters in conventional x-ray sources, owing to their higher aspect ratio, superior mechanical stability, chemical inertness, and high electrical and thermal conductivities. Conditions for realizing the best emission behavior from CNTs have been formulated over the last few years. In this paper, we report the relatively less-investigated factor, namely, the influence of the nature of substrate material on the growth as well as field emission characteristics of large-area multiwalled CNTs for their practical application in medical x-ray sources. We compare the morphology of CNTs on a variety of substrates such as stainless steel, copper, molybdenum, graphite, few-layer graphene, and carbon nanowalls grown by thermal chemical vapor deposition following a simple drop-coating of catalyst. We find that CNTs grown on stainless steel and graphite show the best combination of emission characteristics under pulsed operation mode. These studies are helpful in selecting the optimum substrate material for field emission applications. Ex situ studies on field emission degradation of CNTs are presented towards the end.

  9. Effect of substrate material on the growth and field emission characteristics of large-area carbon nanotube forests

    Science.gov (United States)

    Ummethala, Raghunandan; Wenger, Daniela; Tedde, Sandro F.; Täschner, Christine; Leonhardt, Albrecht; Büchner, Bernd; Eckert, Jürgen

    2016-01-01

    Carbon nanotubes (CNTs) are a promising replacement for tungsten filaments as electron emitters in conventional x-ray sources, owing to their higher aspect ratio, superior mechanical stability, chemical inertness, and high electrical and thermal conductivities. Conditions for realizing the best emission behavior from CNTs have been formulated over the last few years. In this paper, we report the relatively less-investigated factor, namely, the influence of the nature of substrate material on the growth as well as field emission characteristics of large-area multiwalled CNTs for their practical application in medical x-ray sources. We compare the morphology of CNTs on a variety of substrates such as stainless steel, copper, molybdenum, graphite, few-layer graphene, and carbon nanowalls grown by thermal chemical vapor deposition following a simple drop-coating of catalyst. We find that CNTs grown on stainless steel and graphite show the best combination of emission characteristics under pulsed operation mode. These studies are helpful in selecting the optimum substrate material for field emission applications. Ex situ studies on field emission degradation of CNTs are presented towards the end.

  10. CVD growth of large-area and high-quality HfS2 nanoforest on diverse substrates

    Science.gov (United States)

    Zheng, Binjie; Wang, Zegao; Qi, Fei; Wang, Xinqiang; Yu, Bo; Zhang, Wanli; Chen, Yuanfu

    2018-03-01

    Two-dimensional layered transition metal dichalcogenides (TMDs) have attracted burgeoning attention due to their various properties and wide potential applications. As a new TMD, hafnium disulfide (HfS2) is theoretically predicted to have better electrical performance than widely studied MoS2. The experimental researches also confirmed the extraordinary feature in electronics and optoelectronics. However, the maximal device performance may not be achieved due to its own limitation of planar structure and challenge of transfer without contamination. Here, through the chemical vapor deposition (CVD) technique, inch-size HfS2 nanoforest has been directly grown on diverse objective substrates covering insulating, semiconducting and conducting substrates. This direct CVD growth without conventional transfer process avoids contamination and degradation in quality, suggesting its promising and wide applications in high-quality and multifarious devices. It is noted that all the HfS2 nanoforests grown on diverse substrates are constructed with vertically aligned few-layered HfS2 nanosheets with high crystalline quality and edge orientation. Moreover, due to its unique structure, the HfS2 nanoforest owns abundant exposed edge sites and large active surface area, which is essential to apply in high-performance catalyst, sensor, and energy storage or field emitter.

  11. Prebiotic Amino Acid Thioester Synthesis: Thiol-Dependent Amino Acid Synthesis from Formose substrates (Formaldehyde and Glycolaldehyde) and Ammonia

    Science.gov (United States)

    Weber, Arthur L.

    1998-01-01

    Formaldehyde and glycolaldehyde (substrates of the formose autocatalytic cycle) were shown to react with ammonia yielding alanine and homoserine under mild aqueous conditions in the presence of thiol catalysts. Since similar reactions carried out without ammonia yielded alpha-hydroxy acid thioesters, the thiol-dependent synthesis of alanine and homoserine is presumed to occur via amino acid thioesters-intermediates capable of forming peptides. A pH 5.2 solution of 20 mM formaldehyde, 20 mM glycolaldehyde, 20 mM ammonium chloride, 23 mM 3-mercaptopropionic acid, and 23 mM acetic acid that reacted for 35 days at 40 C yielded (based on initial formaldehyde) 1.8% alanine and 0.08% homoserine. In the absence of thiol catalyst, the synthesis of alanine and homoserine was negligible. Alanine synthesis required both formaldehyde and glycolaldehyde, but homoserine synthesis required only glycolaldehyde. At 25 days the efficiency of alanine synthesis calculated from the ratio of alanine synthesized to formaldehyde reacted was 2.1%, and the yield (based on initial formaldehyde) of triose and tetrose intermediates involved in alanine and homoserine synthesis was 0.3 and 2.1%, respectively. Alanine synthesis was also seen in similar reactions containing only 10 mM each of aldehyde substrates, ammonia, and thiol. The prebiotic significance of these reactions that use the formose reaction to generate sugar intermediates that are converted to reactive amino acid thioesters is discussed.

  12. Characterization and growth mechanism of nonpolar and semipolar GaN layers grown on patterned sapphire substrates

    International Nuclear Information System (INIS)

    Okada, Narihito; Tadatomo, Kazuyuki

    2012-01-01

    Nonpolar and semipolar GaN layers with markedly improved crystalline quality can be obtained by selective-area growth from the sapphire sidewalls of patterned sapphire substrates (PSSs). In this paper, we review the crystalline qualities of GaN layers grown on PSSs and their growth mechanism. We grew semipolar {1 1 −2 2} and {1 0 −1 1} GaN layers on r- and n-PSSs. The crystalline qualities of the GaN layers grown on the PSSs were higher than those of GaN layers grown directly on heteroepitaxial substrates. To reveal the growth mechanism of GaN layers grown on PSSs, we also grew various nonpolar and semipolar GaN layers such as m-GaN on a-PSS, {1 1 −2 2} GaN on r-PSS, {1 0 − 1  1} GaN on n-PSS, m-GaN on c-PSS and a-GaN on m-PSS. It was found that the nucleation of GaN on the c-plane-like sapphire sidewall results in selective growth from the sapphire sidewall, and nonpolar or semipolar GaN can be obtained. Finally, we demonstrated a light-emitting diode fabricated on a {1 1 −2 2} GaN layer grown on an r-PSS. (paper)

  13. The growth of aligned carbon nanotubes on quartz substrate by spray pyrolysis of hexane

    International Nuclear Information System (INIS)

    Sadeghian, Zahra

    2008-01-01

    Vertically aligned multiwall carbon nanotubes were grown by spray pyrolysis of hexane as the carbon source in the presence of ferrocene as catalyst precursor on a quartz substrate. In recent work we used optimal experimental parameters for the feeding method, reactor conditions, reaction temperature and time, concentration of catalyst and flow rate of feed and gas. The process parameters were chosen so as to obtain multiwall carbon nanotubes and aligned multiwall carbon nanotubes. The tubes are around 15-80 nm in diameter. The morphology and structure of the samples were characterized by x-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy analyses

  14. Effects of Various Substrates and Foliar Application of Humic Acid ‎on Growth and some Qualitative and Quantitative Characteristics of Tomato (Lycopersicon esculentum Seedling

    Directory of Open Access Journals (Sweden)

    Nasibeh Pourghasemian

    2018-03-01

    Full Text Available Introduction: Successful greenhouse and nursery production of plants is largely dependent on the chemical and physical properties of the growing substrate. An ideal potting substrate should be free of weeds and diseases, heavy enough to avoid frequent tipping over and yet light enough to facilitate handling and shipping. The substrate should also be well drained and yet retain sufficient water to reduce the frequency of watering. Other parameters to consider include cost, availability, consistency between batches and stability in the media over time. Greenhouse crops in general, have higher nutrient demands than field grown crops. Therefore, in order to optimize production it is essential to focus on the growing substrate and fertilization. The physical properties of the growing medium are important parameters for successful plant growth, as these are related to the ability to adequately store and supply air and water to plants. Humic acid is a principal component of humic substances, which are the major organic constituents of soil (humus, peat and coal. It is also a major organic constituent of many upland streams, dystrophic lakes, and ocean water. It is produced by biodegradation of dead organic matter. It is not a single acid, but it is a complex mixture of many different acids containing carboxyl and phenolate groups so that the mixture behaves functionally as a dibasic acid or occasionally as a tribasic acid. Humic acids can form complexes with ions that are commonly found in the environment creating humic colloids. Humic and fulvic acids (fulvic acids are humic acids with lower molecular weight and higher oxygen content than other humic acids are commonly used as a soil supplement in agriculture. Humic Plus contains humic acid, fulvic acid, macro micro nutrients and proprietary constituents essential for plant growth. Organic matter soil amendments have been known by farmers to be beneficial to plant growth for longer than recorded

  15. Substrate dependent self-organization of mesoporous cobalt oxide nanowires with remarkable pseudocapacitance

    KAUST Repository

    Baby, Rakhi Raghavan

    2012-05-09

    A scheme of current collector dependent self-organization of mesoporous cobalt oxide nanowires has been used to create unique supercapacitor electrodes, with each nanowire making direct contact with the current collector. The fabricated electrodes offer the desired properties of macroporosity to allow facile electrolyte flow, thereby reducing device resistance and nanoporosity with large surface area to allow faster reaction kinetics. Co 3O 4 nanowires grown on carbon fiber paper collectors self-organize into a brush-like morphology with the nanowires completely surrounding the carbon microfiber cores. In comparison, Co 3O 4 nanowires grown on planar graphitized carbon paper collectors self-organize into a flower-like morphology. In three electrode configuration, brush-like and flower-like morphologies exhibited specific capacitance values of 1525 and 1199 F/g, respectively, at a constant current density of 1 A/g. In two electrode configuration, the brush-like nanowire morphology resulted in a superior supercapacitor performance with high specific capacitances of 911 F/g at 0.25 A/g and 784 F/g at 40 A/g. In comparison, the flower-like morphology exhibited lower specific capacitance values of 620 F/g at 0.25 A/g and 423 F/g at 40 A/g. The Co 3O 4 nanowires with brush-like morphology exhibited high values of specific power (71 kW/kg) and specific energy (81 Wh/kg). Maximum energy and power densities calculated for Co 3O 4 nanowires with flower-like morphology were 55 Wh/kg and 37 kW/kg respectively. Both electrode designs exhibited excellent cycling stability by retaining ∼91-94% of their maximum capacitance after 5000 cycles of continuous charge-discharge. © 2012 American Chemical Society.

  16. Survival and growth of epiphytic ferns depend on resource sharing

    Directory of Open Access Journals (Sweden)

    Hua-Zheng eLu

    2016-03-01

    Full Text Available Locally available resources can be shared within clonal plant systems through physiological integration, thus enhancing their survival and growth. Most epiphytes exhibit clonal growth habit, but few studies have tested effects of physiological integration (resource sharing on survival and growth of epiphytes and whether such effects vary with species. We conducted two experiments, one on individuals (single ramets and another on groups (several ramets within a plot, with severed and intact rhizome treatments (without and with physiological integration on two dominant epiphytic ferns (Polypodiodes subamoena and Lepisorus scolopendrium in a subtropical montane moist forest in Southwest China. Rhizome severing (preventing integration significantly reduced ramet survival in the individual experiment and number of surviving ramets in the group experiment, and it also decreased biomass of both species in both experiments. However, the magnitude of such integration effects did not vary significantly between the two species. We conclude that resource sharing may be a general strategy for clonal epiphytes to adapt to forest canopies where resources are limited and heterogeneously distributed in space and time.

  17. Frequency dependence of magnetic ac loss in a Roebel cable made of YBCO on a Ni-W substrate

    Science.gov (United States)

    Lakshmi, L. S.; Staines, M. P.; Badcock, R. A.; Long, N. J.; Majoros, M.; Collings, E. W.; Sumption, M. D.

    2010-08-01

    We have investigated the frequency dependent contributions to the magnetic ac loss in a 10 strand Roebel cable with 2 mm wide non-insulated strands and a transposition length of 90 mm. This cable is made from 40 mm wide YBCO coated conductor tape manufactured by AMSC and stabilized by electroplating 25 µm thick copper on either side prior to the mechanical punching of the cable strands. The measurements were carried out in both perpendicular and parallel field orientation, at frequencies in the range of 30-200 Hz. While the loss in the perpendicular orientation is predominantly hysteretic in nature, we observe some frequency dependence of the loss when the cable approaches full flux penetration at high field amplitudes. The magnitude is consistent with eddy current losses in the copper stabilization layer. This supports the fact that the inter-strand coupling loss is not significant in this frequency range. In the parallel field orientation, the hysteresis loss in the Ni-W alloy substrate dominates, but we see an unusually strong frequency dependent contribution to the loss which we attribute to intra-strand current loops.

  18. Molecular beam epitaxy of quasi-freestanding transition metal disulphide monolayers on van der Waals substrates: a growth study

    Science.gov (United States)

    Hall, Joshua; Pielić, Borna; Murray, Clifford; Jolie, Wouter; Wekking, Tobias; Busse, Carsten; Kralj, Marko; Michely, Thomas

    2018-04-01

    Based on an ultra-high vacuum compatible two-step molecular beam epitaxy synthesis with elemental sulphur, we grow clean, well-oriented, and almost defect-free monolayer islands and layers of the transition metal disulphides MoS2, TaS2 and WS2. Using scanning tunneling microscopy and low energy electron diffraction we investigate systematically how to optimise the growth process, and provide insight into the growth and annealing mechanisms. A large band gap of 2.55 eV and the ability to move flakes with the scanning tunneling microscope tip both document the weak interaction of MoS2 with its substrate consisting of graphene grown on Ir(1 1 1). As the method works for the synthesis of a variety of transition metal disulphides on different substrates, we speculate that it could be of great use for providing hitherto unattainable high quality monolayers of transition metal disulphides for fundamental spectroscopic investigations.

  19. Theoretical Investigation on Structural and Electronic Properties of InN Growth on Ce-Stabilized Zirconia (111 Substrates

    Directory of Open Access Journals (Sweden)

    Yao Guo

    2016-01-01

    Full Text Available The structural and electronic properties of InN on Ce-stabilized zirconia (CeSZ (111 substrates are investigated using first-principles calculations based on density functional theory with GGA + U method. Surface energy calculations indicate that the structure of Ce-segregated surface is more energetically stable than that of Ce-segregation-free surface. Adsorption energies of indium and nitrogen atoms on both Ce-segregated and Ce-segregation-free CeSZ (111 surfaces at the initial growth stage have been studied. The results suggest that the first layer of InN films consists of a nitrogen layer, which leads to epitaxial relationships between InN (0001 // CeSZ (111 and InN [112¯0] // CeSZ [11¯0]. In addition, density of states (DOS analysis revealed that the hybridization effect plays a crucial role in determining the interface structure for the growth of InN on CeSZ (111 surfaces. Furthermore, adsorption energies of indium atoms on the nitrogen layer have also been evaluated in order to investigate the lattice polarity determination for InN films. It was found that an indium atom preferentially adsorbs at the center of three nitrogen atoms stacked on the CeSZ substrate, which results in the formation of In-polarity InN.

  20. Growth of ZnO nanowire arrays directly onto Si via substrate topographical adjustments using both wet chemical and dry etching methods

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Nathan A., E-mail: 523615@swansea.ac.uk [Centre for Nanohealth, Department of Physics, College of Science, University of Swansea, Singleton Park SA2 8PP United Kingdom (United Kingdom); Evans, Jon E.; Jones, Daniel R. [Multidisciplinary Nanotechnology Centre, College of Engineering, University of Swansea, Singleton Park, SA2 8PP United Kingdom (United Kingdom); Lord, Alex M. [Centre for Nanohealth, College of Engineering, University of Swansea, Singleton Park, SA2 8PP United Kingdom (United Kingdom); Wilks, S.P. [Centre for Nanohealth, Department of Physics, College of Science, University of Swansea, Singleton Park SA2 8PP United Kingdom (United Kingdom)

    2015-03-15

    Highlights: • Arrays of catalyst-free ZnO NWs have been grown by CVD without seed layers on Si. • Si surface topography was altered by substrate etching, resulting in NW growth. • XPS analysis shows growth is related to topography and not surface contamination. • Using e-beam lithography with etching, selective nanowire growth is demonstrated. • Electrical measurements on the arrays show improved conduction through the Si. - Abstract: Arrays of CVD catalyst-free ZnO nanowires have been successfully grown without the use of seed layers, using both wet chemical and dry plasma etching methods to alter surface topography. XPS analysis indicates that the NW growth cannot be attributed to a substrate surface chemistry and is therefore directly related to the substrate topography. These nanowires demonstrate structural and optical properties typical of CVD ZnO nanowires. Moreover, the NW arrays exhibit a degree of vertical alignment of less than 20° from the substrate normal. Electrical measurements suggest an improved conduction path through the substrate over seed layer grown nanowires. Furthermore, the etching technique was combined with e-beam lithography to produce high resolution selective area nanowire growth. The ability to pattern uniform nanowires using mature dry etch technology coupled with the increased charge transport through the substrate demonstrates the potential of this technique in the vertical integration of nanowire arrays.

  1. Cowpeas as growth substrate do not support the production of aflatoxinby Aspergillus sp

    DEFF Research Database (Denmark)

    Houssou, P.A.; Schnidt-Heydt, M.; Geisen, R.

    2008-01-01

    A number of 21 Aspergillus sp. strains isolated from cowpeas from Benin (Africa) were characterizedby RAPD methodology. Seven of these strains grouped with A. flavus in the dendrogram generated with the RAPD data. Only three were able to produce aflatoxin in significant amounts. Twelve other...... produced high amounts of aflatoxin after growth on YES medium. However after growth on cowpea based medium aflatoxin biosynthesis was strongly ceased, albeit the growth of the colony was only partly reduced. This was true for media made either with the whole cowpea seed or with cowpea seed without seed...... coat. Interestingly when the cowpea medium was heat sterilized the fungus was able to produce high amounts of aflatoxin. This, however, was not the case after the use of gamma irradiation as sterilization method for the medium. The expression of the nor-1 gene, which is one of the early genes involved...

  2. Growth and domain structure of YBa2Cu3Ox films on neodymium gallate substrates with deviation of surface normal from [110] NdGaO3

    International Nuclear Information System (INIS)

    Bdikin, I.K.; Mozhaev, P.B.; Ovsyannikov, G.A.; Komissinskij, F.V.; Kotelyanskij, I.M.; Raksha, E.I.

    2001-01-01

    One investigated into growth, crystalline structure and electrophysical properties of YBa 2 Cu 3 O x (YBCO) epitaxial films grown on NdGaO 3 (NGO) substrates with substrate surface normal deviation from [110] by 5-26.6 deg angle around [001] with CeO 2 epitaxial sublayer or without it. Orientation of YBCO epitaxial films grown at these substrates is shown to be governed by occurrence of symmetrically equipment directions in substrates and in CeO 2 layer, as well as, by film precipitation rate. At precipitation high rate YBCO films on CeO 2 sublayer grow in [001] orientation independently of orientation of substrate and sublayer. One determined that at increase of substrate plane deviation angle from (110) NGO twinning of one or of both twin complexes in YBCO might be suppressed [ru

  3. Growth of InAs Quantum Dots on Germanium Substrate Using Metal Organic Chemical Vapor Deposition Technique

    Directory of Open Access Journals (Sweden)

    Tyagi Renu

    2009-01-01

    Full Text Available Abstract Self-assembled InAs quantum dots (QDs were grown on germanium substrates by metal organic chemical vapor deposition technique. Effects of growth temperature and InAs coverage on the size, density, and height of quantum dots were investigated. Growth temperature was varied from 400 to 450 °C and InAs coverage was varied between 1.40 and 2.35 monolayers (MLs. The surface morphology and structural characteristics of the quantum dots analyzed by atomic force microscope revealed that the density of the InAs quantum dots first increased and then decreased with the amount of InAs coverage; whereas density decreased with increase in growth temperature. It was observed that the size and height of InAs quantum dots increased with increase in both temperature and InAs coverage. The density of QDs was effectively controlled by growth temperature and InAs coverage on GaAs buffer layer.

  4. Microbial utilization of low molecular weight organic substrates in soil depends on their carbon oxidation state

    Science.gov (United States)

    Gunina, Anna; Smith, Andrew; Jones, Davey; Kuzyakov, Yakov

    2017-04-01

    Removal of low molecular weight organic substances (LMWOS), originating from plants and microorganisms, from soil solution is regulated by microbial uptake. In addition to the concentration of LMWOS in soil solution, the chemical properties of each substance (e.g. C oxidation state, number of C atoms, number of -COOH groups) can affect their uptake and subsequent partitioning of C within the soil microbial community. The aim of this study was to trace the initial fate of three dominant classes of LMWOS in soil (sugars, carboxylic and amino acids), including their removal from solution and utilization by microorganisms, and to reveal the effect of substance chemical properties on these processes. Soil solution, spiked at natural abundance levels with 14C-labelled glucose, fructose, malate, succinate, formate, alanine or glycine, was added to the soil and 14C was traced in the dissolved organic carbon (DOC), CO2, cytosol and soil organic carbon (SOC) over 24 hours. The half-life time of all LMWOS in the DOC (T1 /2-solution) varied between 0.6-5.0 min showing extremely fast initial uptake of LMWOS. The T1 /2-solution of substances was dependent on C oxidation state, indicating that less oxidized organic substances (with C oxidation state "0") were retained longer in soil solution than oxidized substances. The LMWOS-C T1 /2-fast, characterizing the half-life time of 14C in the fast mineralization pool, ranged between 30 and 80 min, with the T1 /2-fast of carboxylic acids (malic acid) being the fastest and the T1 /2-fast of amino acids (glycine) being the slowest. An absence of correlation between T1 /2-fast and either C oxidation state, number of C atoms, or number of -COOH groups suggests that intercellular metabolic pathways are more important for LMWOS transformation in soil than their basic chemical properties. The CO2 release during LMWOS mineralization accounted for 20-90% of 14C applied. Mineralization of LMWOS was the least for sugars and the greatest for

  5. Growth of n-alkane films on a single-crystal substrate

    DEFF Research Database (Denmark)

    Wu, Z. U.; Ehrlich, S. N.; Matthies, B.

    2001-01-01

    The structure and growth mode of alkane films (n-C/sub n/H/sub 2n+2/; n=4, 6, 7) adsorbed on a Ag(111) surface have been investigated by synchrotron X-ray scattering. New models are proposed for the butane (n=4) and hexane (n=6) monolayer and butane bilayer structures. Specular reflectivity scans...... reveal that growth of all films is preempted between two and three layers by nucleation of bulk particles oriented with a single bulk crystal plane parallel to the film. In the case of butane, the bulk particles also have a fixed azimuthal relationship with the film resulting in complete epitaxy....

  6. Gas Diffusivity-Based Design and Characterization of Greenhouse Growth Substrates

    DEFF Research Database (Denmark)

    Deepagoda Thuduwe Kankanamge Kelum, Chamindu; Møldrup, Per; Tuller, Markus

    2013-01-01

    combinations thereof, are commonly used as growth media, detailed and comparable physical characterization is key to identify the best performing media. In this study, five potential growth media and two mixtures thereof were characterized based on soil gas diffusivity (Dp/Do, where Dp and Do are gas diffusion...... coefficients in soil air and free air, respectively) and an operationally defined critical window of diffusivity (CWD) representing the interval of air-filled porosity between critical air filled porosity where Dp/Do ≈ 0.02 and interaggregate porosity. The Dp measurements were conducted with 100-cm3 samples...

  7. Impact of phenolic substrate and growth temperature on the arthrobacter chlorophenolicus proteome

    Energy Technology Data Exchange (ETDEWEB)

    Unell, Maria; Abraham, Paul E.; Shah, Manesh; Zhang, Bing; Ruckert, Christian; VerBerkmoes, Nathan C.; Jansson, Janet K.

    2009-02-15

    We compared the Arthrobacter chlorophenolicus proteome during growth on 4-chlorophenol, 4-nitrophenol or phenol at 5 C and 28 C; both for the wild type and a mutant strain with mass spectrometry based proteomics. A label free workflow employing spectral counting identified 3749 proteins across all growth conditions, representing over 70% of the predicted genome and 739 of these proteins form the core proteome. Statistically significant differences were found in the proteomes of cells grown under different conditions including differentiation of hundreds of unknown proteins. The 4-chlorophenol-degradation pathway was confirmed, but not that for phenol.

  8. Growth and lipid production of Umbelopsis isabellina on a solid substrate - Mechanistic modeling and validation

    NARCIS (Netherlands)

    Meeuwse, P.; Klok, A.J.; Haemers, S.; Tramper, J.; Rinzema, A.

    2012-01-01

    Microbial lipids are an interesting feedstock for biodiesel. Their production from agricultural waste streams by fungi cultivated in solid-state fermentation may be attractive, but the yield of this process is still quite low. In this article, a mechanistic model is presented that describes growth,

  9. Growth strategy of heterotrophic bacterial population along successional sequence on spoil of brown coal colliery substrate

    Czech Academy of Sciences Publication Activity Database

    Krištůfek, Václav; Elhottová, Dana; Chroňáková, Alica; Dostálková, I.; Picek, T.; Kalčík, Jiří

    2005-01-01

    Roč. 50, č. 5 (2005), s. 427-435 ISSN 0015-5632 R&D Projects: GA ČR(CZ) GA526/03/1259 Institutional research plan: CEZ:AV0Z60660521 Keywords : growth strategy * heterotrophic bacterial population * brown coal colliery spoil Subject RIV: EH - Ecology, Behaviour Impact factor: 0.918, year: 2005

  10. Dual substrate feedback control of specific growth-rate in vaccine production

    NARCIS (Netherlands)

    Neeleman, R.; Beuvery, E.C.; Vries, D.; Straten, van G.; Boxtel, van A.J.B.

    2004-01-01

    Abstract: Unexpectedly, primary concern of bio-pharmaceutical industry is not optimisation of product yield or cost reduction, but consistency in production and product quality. This paper describes the methodology and experimental results of specific growth-rate control for vaccine production. The

  11. Microbial ecology of extreme environments: Antarctic dry valley yeasts and growth in substrate limited habitats

    Science.gov (United States)

    Vishniac, H. S.

    1981-01-01

    The multiple stresses temperature, moisture, and for chemoheterotrophs, sources of carbon and energy of the Dry Valley Antarctica soils allow at best depauperate communities, low in species diversity and population density. The nature of community structure, the operation of biogeochemical cycles, the evolution and mechanisms of adaptation to this habitat are of interest in informing speculations upon life on other planets as well as in modeling the limits of gene life. Yeasts of the Cryptococcus vishniacil complex (Basidiobiastomycetes) are investigated, as the only known indigenes of the most hostile, lichen free, parts of the Dry Valleys. Methods were developed for isolating these yeasts (methods which do not exclude the recovery of other microbiota). The definition of the complex was refined and the importance of nitrogen sources was established as well as substrate competition in fitness to the Dry Valley habitats.

  12. Growth and Transfer of Monolithic Horizontal ZnO Nanowire Superstructures onto Flexible Substrates

    KAUST Repository

    Xu, Sheng

    2010-04-28

    A method of fabricating horizontally aligned ZnO nanowire (NW) arrays with full control over the width and length is demonstrated. A cross-sectional view of the NWs by transmission electron microscopy shows a "mushroom-like" structure. Novel monolithic multisegment superstructures are fabricated by making use of the lateral overgrowth. Ultralong horizontal ZnO NWs of an aspect ratio on the order often thousand are also demonstrated. These horizontal NWs are lifted off and transferred onto a flexible polymer substrate, which may have many great applications in horizontal ZnO NW-based nanosensor arrays, light-emitting diodes, optical gratings, integrated circuit interconnects, and high-output-power alternating-current nanogenerators. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA.

  13. Fibroblast growth factor receptor mediates fibroblast-dependent growth in EMMPRIN-depleted head and neck cancer tumor cells.

    Science.gov (United States)

    Liu, Zhiyong; Hartman, Yolanda E; Warram, Jason M; Knowles, Joseph A; Sweeny, Larissa; Zhou, Tong; Rosenthal, Eben L

    2011-08-01

    Head and neck squamous cell carcinoma tumors (HNSCC) contain a dense fibrous stroma which is known to promote tumor growth, although the mechanism of stroma-mediated growth remains unclear. As dysplastic mucosal epithelium progresses to cancer, there is incremental overexpression of extracellular matrix metalloprotease inducer (EMMPRIN) which is associated with tumor growth and metastasis. Here, we present evidence that gain of EMMPRIN expression allows tumor growth to be less dependent on fibroblasts by modulating fibroblast growth factor receptor-2 (FGFR2) signaling. We show that silencing EMMPRIN in FaDu and SCC-5 HNSCC cell lines inhibits cell growth, but when EMMPRIN-silenced tumor cells were cocultured with fibroblasts or inoculated with fibroblasts into severe combined immunodeficient mice, the growth inhibition by silencing EMMPRIN was blunted by the presence of fibroblasts. Coculture experiments showed fibroblast-dependent tumor cell growth occurred via a paracrine signaling. Analysis of tumor gene expression revealed expression of FGFR2 was inversely related to EMMPRIN expression. To determine the role of FGFR2 signaling in EMMPRIN-silenced tumor cells, ligands and inhibitors of FGFR2 were assessed. Both FGF1 and FGF2 enhanced tumor growth in EMMPRIN-silenced cells compared with control vector-transfected cells, whereas inhibition of FGFR2 with blocking antibody or with a synthetic inhibitor (PD173074) inhibited tumor cell growth in fibroblast coculture, suggesting the importance of FGFR2 signaling in fibroblast-mediated tumor growth. Analysis of xenografted tumors revealed that EMMPRIN-silenced tumors had a larger stromal compartment compared with control. Taken together, these results suggest that EMMPRIN acquired during tumor progression promotes fibroblast-independent tumor growth.

  14. Fibroblast growth factor receptor mediates fibroblast-dependent growth in EMMPRIN depleted head and neck cancer tumor cells

    Science.gov (United States)

    Liu, Zhiyong; Hartman, Yolanda E.; Warram, Jason M.; Knowles, Joseph A.; Sweeny, Larrisa; Zhou, Tong; Rosenthal, Eben L.

    2011-01-01

    Head and neck squamous cell carcinoma tumors (HNSCC) contain a dense fibrous stroma which is known to promote tumor growth, although the mechanism of stroma mediated growth remains unclear. As dysplastic mucosal epithelium progresses to cancer there is incremental overexpression of extracellular matrix metalloprotease inducer (EMMPRIN) which is associated with tumor growth and metastasis. Here we present evidence that gain of EMMPRIN expression allows tumor growth to be less dependent on fibroblasts by modulating fibroblast growth factor receptor-2 (FGFR2) signaling. We show that silencing EMMPRIN in FaDu and SCC-5 HNSCC cell lines inhibits cell growth, but when EMMPRIN-silenced tumor cells were co-cultured with fibroblasts or inoculated with fibroblasts into SCID mice, the growth inhibition by silencing EMMPRIN was blunted by the presence of fibroblasts. Co-culture experiments demonstrated fibroblast-dependent tumor cell growth occurred via a paracrine signaling. Analysis of tumor gene expression revealed expression of FGFR2 was inversely related to EMMPRIN expression. To determine the role of FGFR2 signaling in EMMPRIN silenced tumor cells, ligands and inhibitors of FGFR2 were assessed. Both FGF1 and FGF2 enhanced tumor growth in EMMPRIN silenced cells compared to control vector transfected cells, while inhibition of FGFR2 with blocking antibody or with a synthetic inhibitor (PD173074) inhibited tumor cell growth in fibroblast co-culture, suggesting the importance of FGFR2 signaling in fibroblast mediated tumor growth. Analysis of xenografted tumors revealed EMMPRIN silenced tumors had a larger stromal compartment compared to control. Taken together, these results suggest that EMMPRIN acquired during tumor progression promotes fibroblast independent tumor growth. PMID:21665938

  15. Electrochemical behaviour and nanoscale characteristics of CNT-based fibers as new substrate for cell growth

    Energy Technology Data Exchange (ETDEWEB)

    Polizu, S.; Yahia, L.H. [Ecole Polytechnique de Montreal, PQ (Canada). Laboratoire d' innovation et d' analyse de la bioperformance; Savadogo, O. [Ecole Polytechnique de Montreal, Montreal, PQ (Canada). Laboratoire de nouveaux materiaux pour l' energie et l' electrochimie; Maugey, M.; Poulin, P. [Centre de Recherche Paul Pascal, CNRS, Bordeaux (France); Rouabhia, M. [Laval Univ., Quebec City, PQ (Canada). Faculty of Medicine

    2008-07-01

    This paper reported on a study in which carbon nanotube (CNT) macroscopic fibers were formulated by a newly developed non-covalent method for fabricating fibrous substrate. The covalent and noncovalent chemistry of CNTs has been widely used in the development of CNT-based biomaterials as active substrates for living cells. Time of Flight Mass Spectroscopy (TOF-SIMS) analysis was used to determine the surface characteristics of the CNT-based fibers produced by wet spinning method. The structure and texture of fibers were imaged using Low-Vacuum Scanning Electron Microscopy (LV-SEM) equipped with an Energy Dispersive Spectrometer (EDS) for microanalysis. Atomic Force Microscopy (AFM) imaging revealed the structure of fibers. Cyclic Voltametry (CV) measurements were performed to examine the electrochemical behaviour of fibers. Sulfuric acid and a cell culture medium was used as the 2 different electrolytes. The influences of environmental parameters on the electrochemical phenomena taking place were identified. The intrinsic electrochemical characteristics of fibers were revealed through measurements in acid environment. The cell culture medium simulated the physiological conditions. It was concluded that the newly developed wet spinning method is very efficient for making CNT-based fibers as electroactive biomaterials. The structural nanoscale details evidenced a good alignment of nanotubes in the thread and the critical role it plays in electrochemical interactions. The differences induced by the variation of electrolytes suggest that a relationship could be established between the fiber chemistry and the electrochemical response. This correlation has considerably potential for the design of new biomedical devices. 2 refs.

  16. Controlling growth rate anisotropy for formation of continuous ZnO thin films from seeded substrates

    International Nuclear Information System (INIS)

    Zhang, R H; Slamovich, E B; Handwerker, C A

    2013-01-01

    Solution-processed zinc oxide (ZnO) thin films are promising candidates for low-temperature-processable active layers in transparent thin film electronics. In this study, control of growth rate anisotropy using ZnO nanoparticle seeds, capping ions, and pH adjustment leads to a low-temperature (90 ° C) hydrothermal process for transparent and high-density ZnO thin films. The common 1D ZnO nanorod array was grown into a 2D continuous polycrystalline film using a short-time pure solution method. Growth rate anisotropy of ZnO crystals and the film morphology were tuned by varying the chloride (Cl − ) ion concentration and the initial pH of solutions of zinc nitrate and hexamethylenetetramine (HMTA), and the competitive adsorption effects of Cl − ions and HMTA ligands on the anisotropic growth behavior of ZnO crystals were proposed. The lateral growth of nanorods constituting the film was promoted by lowering the solution pH to accelerate the hydrolysis of HMTA, thereby allowing the adsorption effects from Cl − to dominate. By optimizing the growth conditions, a dense ∼100 nm thickness film was fabricated in 15 min from a solution of [Cl − ]/[Zn 2+ ] = 1.5 and pH= 4.8 ± 0.1. This film shows >80% optical transmittance and a field-effect mobility of 2.730 cm 2 V −1 s −1 at zero back-gate bias. (paper)

  17. Thickness dependence of microstructures in La0.9Sr0.1MnO3 thin films grown on exact-cut and miscut SrTiO3 substrates

    International Nuclear Information System (INIS)

    Zhang Hongdi; An Yukai; Mai Zhenhong; Lu Huibin; Zhao Kun; Pan Guoqiang; Li Ruipeng; Fan Rong

    2008-01-01

    The thickness dependence of microstructures of La 0.9 Sr 0.1 MnO 3 (LSMO) thin films grown on exact-cut and miscut SrTiO 3 (STO) substrates, respectively, was investigated by high-angle X-ray diffraction (HXRD), X-ray small-angle reflection (XSAR), X-ray reciprocal space mapping and atomic force microscopy (AFM). Results show that the LSMO films are in pseudocubic structure and are highly epitaxial [0 0 1]-oriented growth on the (0 0 1) STO substrates. The crystalline quality of the LSMO film is improved with thickness. The epitaxial relationship between the LSMO films and the STO substrates is [0 0 1] LSMO -parallel [0 0 1] EXACT-STO , and the LSMO films have a slight mosaic structure along the q x direction for the samples grown on the exact-cut STO substrates. However, an oriented angle of about 0.24 deg. exists between [0 0 1] LSMO and [0 0 1] MISCUT-STO , and the LSMO films have a mosaic structure along the q z direction for that grown on the miscut STO substrates. The mosaic structure of both groups of the samples tends to reduce with thickness. The diffraction intensity of the (0 0 4) peaks increases with thickness of the LSMO film. The XSAR and AFM observations show that for both groups, the interface is sharp and the surface is rather smooth. The mechanism was discussed briefly

  18. Salicylic acid modulates levels of phosphoinositide dependent-phospholipase C substrates and products to remodel the Arabidopsis suspension cell transcriptome

    Directory of Open Access Journals (Sweden)

    Eric eRuelland

    2014-11-01

    Full Text Available Basal phosphoinositide-dependent phospholipase C (PI-PLC activity controls gene expression in Arabidopsis suspension cells and seedlings. PI-PLC catalyzes the production of phosphorylated inositol and diacylglycerol (DAG from phosphoinositides. It is not known how PI-PLC regulates the transcriptome although the action of DAG-kinase (DGK on DAG immediately downstream from PI-PLC is responsible for some of the regulation. We previously established a list of genes whose expression is affected in the presence of PI-PLC inhibitors. Here this list of genes was used as a signature in similarity searches of curated plant hormone response transcriptome data. The strongest correlations obtained with the inhibited PI-PLC signature were with salicylic acid (SA treatments. We confirm here that in Arabidopsis suspension cells SA treatment leads to an increase in phosphoinositides, then demonstrate that SA leads to a significant 20% decrease in phosphatidic acid, indicative of a decrease in PI-PLC products. Previous sets of microarray data were re-assessed. The SA response of one set of genes was dependent on phosphoinositides. Alterations in the levels of a second set of genes, mostly SA-repressed genes, could be related to decreases in PI-PLC products that occur in response to SA action. Together, the two groups of genes comprise at least 40% of all SA-responsive genes. Overall these two groups of genes are distinct in the functional categories of the proteins they encode, their promoter cis-elements and their regulation by DGK or phospholipase D. SA-regulated genes dependent on phosphoinositides are typical SA response genes while those with an SA response that is possibly dependent on PI-PLC products are less SA-specific. We propose a model in which SA inhibits PI-PLC activity and alters levels of PI-PLC products and substrates, thereby regulating gene expression divergently.

  19. Real-time optical modelling and investigation of inorganic nano-layer growth onto flexible polymeric substrates

    International Nuclear Information System (INIS)

    Laskarakis, A.; Georgiou, D.; Logothetidis, S.

    2010-01-01

    A major factor for the achievement of the desirable performance, efficiency and lifetime of flexible organic electronic devices is the optimization of the encapsulation layers that protect the device active layers by atmospheric gas molecule permeation. The active layers consisted of small molecule and/or polymer organic semiconductors as well as the organic conductors need to be encapsulated into a transparent medium that will provide the necessary protection and maintain their charge generation and transport characteristics. The encapsulation layers are generally consisted of inorganic thin films (silicon oxide-SiO x and aluminium oxide-AlO x ) deposited onto the polymeric substrates, such as PolyEthylene Terephthalate (PET). In this work, in situ and real-time Spectroscopic Ellipsometry in the ultraviolet spectral region has been implemented in order to investigate the growth of inorganic SiO x and AlO x nano-layers onto PET flexible polymeric substrates as well as the PET/inorganic interface effects during the early stages of growth. The analysis of the pseudodielectric function that was measured in real-time in very short time scales (in the order of hundreds of ms) has provided detailed information on the time evolution of the thickness and deposition rate of the inorganic nano-layers during their growth process as well as on their optical and electronic properties. This work proposes a methodology for using real-time optical monitoring technique with the aim to tailor and control the functionality of these materials for application in flexible electronic devices.

  20. Growth of cubic GaN on a nitrided AlGaAs (001) substrate by using hydried vapor phase epitaxy

    International Nuclear Information System (INIS)

    Lee, H. J.; Yang, M.; Ahn, H. S.; Kim, K. H.; Yi, J. Y.; Jang, K. S.; Chang, J. H.; Kim, H. S.; Cho, C. R.; Kim, S. W.

    2006-01-01

    GaN layers were grown on AlGaAs (001) substrates by using hydride vapor phase epitaxy (HVPE). Growth parameters such as the nitridation temperature of the AlGaAs substrate and the growth rate of the GaN layer were found to be critical determinants for the growth of cubic GaN layer. Nitridation of the AlGaAs surface was performed in a NH 3 atmosphere at a temperature range of 550 - 700 .deg. C. GaN layers were grown at different growth rates on the nitrided AlGaAs substrates. The surface morphologies and the chemical constituents of the nitrided AlGaAs layers were characterized with scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). For the optical and the crystalline characterization of the GaN films, cathodoluminescence (CL) and X-ray diffraction (XRD) were carried out.

  1. Reactive Oxygen Species (ROS)-Activated ATM-Dependent Phosphorylation of Cytoplasmic Substrates Identified by Large-Scale Phosphoproteomics Screen*

    Science.gov (United States)

    Kozlov, Sergei V.; Waardenberg, Ashley J.; Engholm-Keller, Kasper; Arthur, Jonathan W.; Graham, Mark E.; Lavin, Martin

    2016-01-01

    Ataxia-telangiectasia, mutated (ATM) protein plays a central role in phosphorylating a network of proteins in response to DNA damage. These proteins function in signaling pathways designed to maintain the stability of the genome and minimize the risk of disease by controlling cell cycle checkpoints, initiating DNA repair, and regulating gene expression. ATM kinase can be activated by a variety of stimuli, including oxidative stress. Here, we confirmed activation of cytoplasmic ATM by autophosphorylation at multiple sites. Then we employed a global quantitative phosphoproteomics approach to identify cytoplasmic proteins altered in their phosphorylation state in control and ataxia-telangiectasia (A-T) cells in response to oxidative damage. We demonstrated that ATM was activated by oxidative damage in the cytoplasm as well as in the nucleus and identified a total of 9,833 phosphorylation sites, including 6,686 high-confidence sites mapping to 2,536 unique proteins. A total of 62 differentially phosphorylated peptides were identified; of these, 43 were phosphorylated in control but not in A-T cells, and 19 varied in their level of phosphorylation. Motif enrichment analysis of phosphopeptides revealed that consensus ATM serine glutamine sites were overrepresented. When considering phosphorylation events, only observed in control cells (not observed in A-T cells), with predicted ATM sites phosphoSerine/phosphoThreonine glutamine, we narrowed this list to 11 candidate ATM-dependent cytoplasmic proteins. Two of these 11 were previously described as ATM substrates (HMGA1 and UIMCI/RAP80), another five were identified in a whole cell extract phosphoproteomic screens, and the remaining four proteins had not been identified previously in DNA damage response screens. We validated the phosphorylation of three of these proteins (oxidative stress responsive 1 (OSR1), HDGF, and ccdc82) as ATM dependent after H2O2 exposure, and another protein (S100A11) demonstrated ATM-dependence

  2. RhoA-Mediated Functions in C3H10T1/2 Osteoprogenitors Are Substrate Topography Dependent.

    Science.gov (United States)

    Ogino, Yoichiro; Liang, Ruiwei; Mendonça, Daniela B S; Mendonça, Gustavo; Nagasawa, Masako; Koyano, Kiyoshi; Cooper, Lyndon F

    2016-03-01

    Surface topography broadly influences cellular responses. Adherent cell activities are regulated, in part, by RhoA, a member of the Rho-family of GTPases. In this study, we evaluated the influence of surface topography on RhoA activity and associated cellular functions. The murine mesenchymal stem cell line C3H10T1/2 cells (osteoprogenitor cells) were cultured on titanium substrates with smooth topography (S), microtopography (M), and nanotopography (N) to evaluate the effect of surface topography on RhoA-mediated functions (cell spreading, adhesion, migration, and osteogenic differentiation). The influence of RhoA activity in the context of surface topography was also elucidated using RhoA pharmacologic inhibitor. Following adhesion, M and N adherent cells developed multiple projections, while S adherent cells had flattened and widespread morphology. RhoA inhibitor induced remarkable longer and thinner cytoplasmic projections on all surfaces. Cell adhesion and osteogenic differentiation was topography dependent with S topography roughness dependent (S topography. Smooth surface adherent cells appear highly sensitive to RhoA function, while nano-scale topography adherent cell may utilize alternative cellular signaling pathway(s) to influence adherent cellular functions regardless of RhoA activity. © 2015 Wiley Periodicals, Inc.

  3. Characterization of Angle Dependent Color Travel of Printed Multi-Color Effect Pigment on Different Color Substrates

    Directory of Open Access Journals (Sweden)

    Mirica Karlovits

    2015-03-01

    Full Text Available Color-travel pigments, which exhibit much more extensive color change as well provide angle-dependent optical effect can be used in many industrial products. In present paper the multi-color effect pigment printed on three different foils with different background color (black, silver and transparent was investigated. The pigment was based on synthetically produced transparent silicon dioxide platelets coated with titanium dioxide. CIEL*a*b* values and reflection of prints were measured by multi-angle spectrophotometer at constant illumination at an angle of 45º and different viewing angles (-15º, 15°, 25º, 45º, 75º and 110º were used. The measurements of printed multi-color pigment showed that CIEL*a*b* color coordinates varied to great extents, depending on detection angles as well on color of the printing substrate. The study revealed that pigmnet printed on black background obtained significant change in color. The study has also shown that when viewing angle increases, the reflection curves decreases.

  4. Dysprosium-Catalyzed Growth of Single-Walled Carbon Nanotube Arrays on Substrates

    Directory of Open Access Journals (Sweden)

    Qian Yong

    2009-01-01

    Full Text Available Abstract In this letter, we report that dysprosium is an effective catalyst for single-walled carbon nanotubes (SWNTs growth via a chemical vapor deposition (CVD process for the first time. Horizontally superlong well-oriented SWNT arrays on SiO2/Si wafer can be fabricated by EtOH-CVD under suitable conditions. The structure and properties are characterized by scanning electron microscopy, transition electron microscopy, Raman spectroscopy and atomic force microscopy. The results show that the SWNTs from dysprosium have better structural uniformity and better conductivity with fewer defects. This rare earth metal provides not only an alternative catalyst for SWNTs growth, but also a possible method to generate high percentage of superlong semiconducting SWNT arrays for various applications of nanoelectronic device.

  5. Population Growth Parameters of Tuta absoluta (Lepidoptera: Gelechiidae) on Tomato Plant Using Organic Substrate and Biofertilizers.

    Science.gov (United States)

    Mohamadi, P; Razmjou, J; Naseri, B; Hassanpour, M

    2017-01-01

    The tomato leafminer, Tuta absoluta (Meyrick) is a devastating pest associated with tomato. In this study, effects of tomato plants treated with vermicompost (20, 40, and 60%), humic fertilizer (2, 4 and 6 g/kg soil) and plant growth promoting rhizobacteria (Pseudomonas fluorescens and Bacillus subtilis) were investigated on the life table parameters of T. absoluta in a growth chamber at 25 ± 2 °C, 65 ± 5% RH, and 16:8 (L:D) h. Significant differences were found for the total developmental time, fecundity, and oviposition period of T. absoluta on the treatments tested. The net reproductive rate (R0), intrinsic rate of natural increase (rm), finite rate of increase (λ), mean generation time (T), and doubling time (DT) of T. absoluta were significantly different among treatments tested. We found that in all vermicompost, humic fertilizer and plant growth promoting rhizobacteria treatments, values of R0, rm, and λ were lower than control treatment. However, the lowest values of these parameters were obtained on 2 g/kg humic fertilizer and 40% vermicompost. Furthermore, T. absoluta had longest T and DT values on 2 g/kg humic fertilizer treatment. Data obtained showed that the addition of 2 g/kg humic fertilizer and 40% vermicompost to the growing soil reduced T. absoluta populations in tomato cultures. In addition, these levels of fertilizers improved growth parameters of tomato seedlings (plant height, wet weight, and dry weight) compared with other treatments. These results could be useful in improving the sustainable management of the moth. © The Author 2017. Published by Oxford University Press on behalf of the Entomological Society of America.

  6. Codon 972 polymorphism in the insulin receptor substrate-1 gene, obesity, and risk of noninsulin-dependent diabetes mellitus

    Energy Technology Data Exchange (ETDEWEB)

    Sigal, R.J.; Doria, A.; Warram, J.H.; Krolewski, A.S. [Joslin Diabetes Center, Boston, MA (United States)

    1996-04-01

    Because of the role of insulin receptor substrate-1 in insulin action, the insulin receptor substrate-1 gene is a candidate gene for noninsulin-dependent diabetes mellitus (NIDDM). Modest associations between NIDDM and a GGG-AGG single base substitution (corresponding to a glycine-arginine amino acid substitution) in codon 972 of the gene have been found, but none reached statistical significance. To examine further how large a proportion of NIDDM cases could be caused by the mutation, we performed a stratified analysis combining the results from the 6 earlier studies and those from our panel of 192 unrelated NIDDM subjects and 104 healthy controls. In addition, we looked for a possibility that the codon 972 mutation plays a role only in the presence of certain conditions. Genomic DNA samples obtained from NIDDM cases and healthy controls were genotyped using a PCR-restriction fragment length polymorphism protocol modified for genomic DNA. The GGG{r_arrow}AGG substitution was found in 5.7% of the diabetic subjects (11 of 192) and 6.9% of the controls (7 of 104). The difference between groups was not statistically significant, and it was not different from the results of other studies. The Mantel-Haenszel summary odds ratio across all studies was 1.49 (P < 0.05; 95% confidence intervals, 1.01-2.2). This summary odds ratio is consistent with a small proportion of NIDDM cases ({approximately}3%) being caused by the mutation. Exploratory subgroup analyses on our panel suggested a clustering of NIDDM, the codon 972 mutation, and overweight, raising the hypothesis that the mutation may predispose to NIDDM only in the presence of excess body weight. 9 refs., 2 tabs.

  7. Effect of Bifidobacterium upon Clostridium difficile growth and toxicity when co-cultured in different prebiotic substrates

    Directory of Open Access Journals (Sweden)

    Lorena Valdés Varela

    2016-05-01

    Full Text Available The intestinal overgrowth of Clostridium difficile, often after disturbance of the gut microbiota by antibiotic treatment, leads to C. difficile infection (CDI which manifestation ranges from mild diarrhoea to life-threatening conditions. The increasing CDI incidence, not only in compromised subjects but also in traditionally considered low-risk populations, together with the frequent relapses of the disease, has attracted the interest for prevention/therapeutic options. Among these, probiotics, prebiotics or synbiotics constitute a promising approach. In this study we determined the potential of selected Bifidobacterium strains for the inhibition of C. difficile growth and toxicity in different carbon sources. We conducted co-cultures of the toxigenic strain C. difficile LMG21717 with four Bifidobacterium strains (Bifidobacterium longum IPLA20022, Bifidobacterium breve IPLA20006, Bifidobacterium bifidum IPLA20015, and Bifidobacterium animalis subsp. lactis Bb12 in the presence of various prebiotic substrates (Inulin, Synergy and Actilight or glucose, and compared the results with those obtained for the corresponding mono-cultures. C. difficile and bifidobacteria levels were quantified by qPCR; the pH and the production of short chain fatty acids was also determined. Moreover, supernatants of the cultures were collected to evaluate their toxicity using a recently developed model. Results showed that co-culture with B. longum IPLA20022 and B. breve IPLA20006 in the presence of short-chain fructooligosaccharides, but not of Inulin, as carbon source significantly reduced the growth of the pathogen. With the sole exception of B. animalis Bb12, whose growth was enhanced, the presence of C. difficile did not show major effects upon the growth of the bifidobacteria. In accordance with the growth data, B. longum and B. breve were the strains showing higher reduction in the toxicity of the co-culture supernatants.

  8. RETRACTED: Nucleation and growth behavior of well-aligned ZnO nanorods on organic substrates in aqueous solutions

    Science.gov (United States)

    Lin, Chin-Ching; Chen, San-Yuan; Cheng, Syh-Yuh

    2005-09-01

    Available online : 21 July 2005 This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. Two papers published in the Journal of Crystal Growth are being retracted due to a case of misrepresentation and reuse of data. A reader of the Journal has brought to our attention the reuse of data within two published papers: Growth behavior and microstructure evolution of ZnO nanorods grown on Si in aqueous solution, Sz-Chian Liou, Chi-Sheng Hsiao, San-Yuan Chen, Journal of Crystal Growth 274 (2005) 438-446. DOI: 10.1016/j.jcrysgro.2004.10.025 Nucleation and growth behavior of well-aligned ZnO nanorods on organic substrates in aqueous solutions, Chin-Ching Lin, San-Yuan Chen, and Syh-Yuh Cheng, Journal of Crystal Growth 283 (2005) 141-146. DOI: 10.1016/j.jcrysgro.2005.05.065 In these papers the same transmission electron micrograph was used to describe two different experimental situations and results bringing into question the content of these papers. The reuse of data without proper attribution is not acceptable within the scientific publishing community. In the present case, this is compounded by the attribution of the micrograph to a different experimental situation and drawing , as a result, new conclusions from data obtained from different samples. Such behavior undermines the integrity of the scientific publishing endeavor and is not acceptable. The authors are responsible for the content of their papers.

  9. Temperature effect on the growth of Au-free InAs and InAs/GaSb heterostructure nanowires on Si substrate by MOCVD

    Science.gov (United States)

    Kakkerla, Ramesh Kumar; Anandan, Deepak; Hsiao, Chih-Jen; Yu, Hung Wei; Singh, Sankalp Kumar; Chang, Edward Yi

    2018-05-01

    We demonstrate the growth of vertically aligned Au-free InAs and InAs/GaSb heterostructure nanowires on Si (1 1 1) substrate by Metal Organic Chemical Vapor Deposition (MOCVD). The effect of growth temperature on the morphology and growth rate of the InAs and InAs/GaSb heterostructure nanowires (NWs) is investigated. Control over diameter and length of the InAs NWs and the GaSb shell thickness was achieved by using growth temperature. As the GaSb growth temperature increase, GaSb radial growth rate increases due to the increase in alkyl decomposition at the substrate surface. Diffusivity of the adatoms increases as the GaSb growth temperature increase which results in tapered GaSb shell growth. Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) measurements revealed that the morphology and shell thickness can be tuned by the growth temperature. Electron microscopy also shows the formation of GaSb both in radial and axial directions outside the InAs NW core can be controlled by the growth temperature. This study demonstrates the control over InAs NWs growth and the GaSb shell thickness can be achieved through proper growth temperature control, such technique is essential for the growth of nanowire for future nano electronic devices, such as Tunnel FET.

  10. Effect of growth temperature on the morphology and phonon properties of InAs nanowires on Si substrates

    Directory of Open Access Journals (Sweden)

    Lei Wen

    2011-01-01

    Full Text Available Abstract Catalyst-free, vertical array of InAs nanowires (NWs are grown on Si (111 substrate using MOCVD technique. The as-grown InAs NWs show a zinc-blende crystal structure along a < 111 > direction. It is found that both the density and length of InAs NWs decrease with increasing growth temperatures, while the diameter increases with increasing growth temperature, suggesting that the catalyst-free growth of InAs NWs is governed by the nucleation kinetics. The longitudinal optical and transverse optical (TO mode of InAs NWs present a phonon frequency slightly lower than those of InAs bulk materials, which are speculated to be caused by the defects in the NWs. A surface optical mode is also observed for the InAs NWs, which shifts to lower wave-numbers when the diameter of NWs is decreased, in agreement with the theory prediction. The carrier concentration is extracted to be 2.25 × 1017 cm-3 from the Raman line shape analysis. A splitting of TO modes is also observed. PACS: 62.23.Hj; 81.07.Gf; 63.22.Gh; 61.46.Km

  11. An Efficient Explicit Finite-Difference Scheme for Simulating Coupled Biomass Growth on Nutritive Substrates

    Directory of Open Access Journals (Sweden)

    G. F. Sun

    2015-01-01

    Full Text Available A novel explicit finite-difference (FD method is presented to simulate the positive and bounded development process of a microbial colony subjected to a substrate of nutrients, which is governed by a nonlinear parabolic partial differential equations (PDE system. Our explicit FD scheme is uniquely designed in such a way that it transfers the nonlinear terms in the original PDE into discrete sets of linear ones in the algebraic equation system that can be solved very efficiently, while ensuring the stability and the boundedness of the solution. This is achieved through (1 a proper design of intertwined FD approximations for the diffusion function term in both time and spatial variations and (2 the control of the time-step through establishing theoretical stability criteria. A detailed theoretical stability analysis is conducted to reveal that our FD method is indeed stable. Our examples verified the fact that the numerical solution can be ensured nonnegative and bounded to simulate the actual physics. Numerical examples have also been presented to demonstrate the efficiency of the proposed scheme. The present scheme is applicable for solving similar systems of PDEs in the investigation of the dynamics of biological films.

  12. Anisotropic corner diffusion as origin for dendritic growth on hexagonal substrates

    DEFF Research Database (Denmark)

    Brune, H.; Röder, H.; Bromann, K.

    1996-01-01

    Ag aggregation on Ag(111), Pt(111), and 1 ML Ag pseudomorphically grown on Pt(111), has been studied with variable temperature STM. These systems all have in common that dendritic patterns with trigonal symmetry rather than randomly ramified aggregates, which would be expected for a simple hit an...... theory show that this relaxation is highly asymmetric with respect to the two different kinds of close-packed steps. It leads to dendritic growth as verified by kinetic Monte-Carlo simulations which agree well with experiment....

  13. Effect of Time-Dependent Pinning Pressure on Abnormal Grain Growth: Phase Field Simulation

    Science.gov (United States)

    Kim, Jeong Min; Min, Guensik; Shim, Jae-Hyeok; Lee, Kyung Jong

    2018-05-01

    The effect of the time-dependent pinning pressure of precipitates on abnormal grain growth has been investigated by multiphase field simulation with a simple precipitation model. The application of constant pinning pressure is problematic because it always induces abnormal grain growth or no grain growth, which is not reasonable considering the real situation. To produce time-dependent pinning pressure, both precipitation kinetics and precipitate coarsening kinetics have been considered with two rates: slow and fast. The results show that abnormal grain growth is suppressed at the slow precipitation rate. At the slow precipitation rate, the overall grain growth caused by the low pinning pressure in the early stage indeed plays a role in preventing abnormal grain growth by reducing the mobility advantage of abnormal grains. In addition, the fast precipitate coarsening rate tends to more quickly transform abnormal grain growth into normal grain growth by inducing the active growth of grains adjacent to the abnormal grains in the early stage. Therefore, the present study demonstrates that the time dependence of the pinning pressure of precipitates is a critical factor that determines the grain growth mode.

  14. Oil palm waste and synthetic zeolite: an alternative soil-less growth substrate for lettuce production as a waste management practice

    Energy Technology Data Exchange (ETDEWEB)

    Jayasinghe, G.Y.; Tokashiki, Y.; Kitou, M.; Kinjo, K. [Kagoshima University, Kagoshima (Japan). United Graduate School of Agricultural Science

    2008-12-15

    A study was conducted to assess the characteristics and the prospective utilization of oil palm waste (OP) and synthetic zeolite (SZ) developed by coal fly ash, as an alternative substrate to peat and commercial perlite for lettuce (Lactuca sativa L.) production. The SZ, OP, sphagnum peat (PE), perlite (PL) and two different SZ-OP mixtures (v/v) at the ratio of 1 : 3 and 1 : 10 were utilized as the substrates under this study. The substrates formulated by mixing SZ with OP at the ratio of 1 : 3 and 1 : 10 showed improved substrate physical and chemical properties such as air space, bulk density, particle density, water-holding capacity, pH and electrical conductivity (EC), which were in the ideal substrate range when compared with PL. Furthermore, the water-holding capacity of the substrate having a 1 : 10 mixing ratio of SZ with OP was higher than that of the PL by 28.23%, whereas the bulk density was lower than that of PL by 35%. A greenhouse experiment was carried out to assess the influence of the substrates on the growth and development of lettuce. The results of the study suggest that the SZ-OP-based substrates and OP can be successfully utilized as alternatives to the commercial perlite and to substitute the conventional peat substrate for lettuce cultivation. In addition, this can be proposed as an alternative waste management practice.

  15. Caenorhabditis elegans fibroblast growth factor receptor signaling can occur independently of the multi-substrate adaptor FRS2.

    Science.gov (United States)

    Lo, Te-Wen; Bennett, Daniel C; Goodman, S Jay; Stern, Michael J

    2010-06-01

    The components of receptor tyrosine kinase signaling complexes help to define the specificity of the effects of their activation. The Caenorhabditis elegans fibroblast growth factor receptor (FGFR), EGL-15, regulates a number of processes, including sex myoblast (SM) migration guidance and fluid homeostasis, both of which require a Grb2/Sos/Ras cassette of signaling components. Here we show that SEM-5/Grb2 can bind directly to EGL-15 to mediate SM chemoattraction. A yeast two-hybrid screen identified SEM-5 as able to interact with the carboxy-terminal domain (CTD) of EGL-15, a domain that is specifically required for SM chemoattraction. This interaction requires the SEM-5 SH2-binding motifs present in the CTD (Y(1009) and Y(1087)), and these sites are required for the CTD role of EGL-15 in SM chemoattraction. SEM-5, but not the SEM-5 binding sites located in the CTD, is required for the fluid homeostasis function of EGL-15, indicating that SEM-5 can link to EGL-15 through an alternative mechanism. The multi-substrate adaptor protein FRS2 serves to link vertebrate FGFRs to Grb2. In C. elegans, an FRS2-like gene, rog-1, functions upstream of a Ras/MAPK pathway for oocyte maturation but is not required for EGL-15 function. Thus, unlike the vertebrate FGFRs, which require the multi-substrate adaptor FRS2 to recruit Grb2, EGL-15 can recruit SEM-5/Grb2 directly.

  16. GROWTH AND LEVELS OF N, P AND K IN ROOTSTOCKS OF TAMARIND TREES USING ORGANIC SUBSTRATES AND DOSES OF PHOSPHORUS

    Directory of Open Access Journals (Sweden)

    EDUARDO CASTRO PEREIRA

    2016-01-01

    Full Text Available The aim of this study was to evaluate different organic substrates and phosphorus doses on the growth and leaf content of nitrogen, phosphorus and potassium in rootstocks of Tamarindus indica L. The experiment was performed in a greenhouse nursery located on the campus of the Universidade Federal Rural do Semi-Árido (UFERSA, from March to October 2013. The treatments consisted of three organic sources at a concentration of 40% (v/v (bovine manure, goat manure and a commercial organic compound and four doses of simple superphosphate (0, 0 kg m-3, 2.5 kg m-3, 5.0 kg m-3 and 7.5 kg m-3. The experiment was conducted in a randomized block design (RBD, with 12 treatments (substrates, four replications and 10 plants per plot, totaling 480 plants. The goat manure and the organic compound were the most suitable treatments for the production of rootstocks of the tamarind tree. The maximum dose of 7.5 g kg-1 of simple superphosphate caused the highest levels of phosphorus and potassium in the dry mass of shoots. The nutrients in the dry matter of shoots accumulated in the following order: N > K > P.

  17. Growth and characterization of polar and nonpolar ZnO film grown on sapphire substrates by using atomic layer deposition

    International Nuclear Information System (INIS)

    Kim, Ki-Wook; Son, Hyo-Soo; Choi, Nak-Jung; Kim, Jihoon; Lee, Sung-Nam

    2013-01-01

    We investigated the electrical and the optical properties of polar and nonpolar ZnO films grown on sapphire substrates with different crystallographic planes. High resolution X-ray results revealed that polar c-plane (0001), nonpolar m-plane (10-10) and a-plane (11-20) ZnO thin films were grown on c-plane, m- and r-sapphire substrates by atomic layer deposition, respectively. Compared with the c-plane ZnO film, nonpolar m-plane and a-plane ZnO films showed smaller surface roughness and anisotropic surface structures. Regardless of ZnO crystal planes, room temperature photoluminescence spectra represented two emissions which consisted of the near bandedge (∼ 380 nm) and the deep level emission (∼ 500 nm). The a-plane ZnO films represented better optical and electrical properties than c-plane ZnO, while m-plane ZnO films exhibited poorer optical and electrical properties than c-plane ZnO. - Highlights: • Growth and characterization of a-, c- and m-plane ZnO film by atomic layer deposition. • The a-plane ZnO represented better optical and electrical properties than c-plane ZnO. • The m-plane ZnO exhibited poorer optical and electrical properties than c-plane ZnO

  18. Facile Five-Step Heteroepitaxial Growth of GaAs Nanowires on Silicon Substrates and the Twin Formation Mechanism.

    Science.gov (United States)

    Yao, Maoqing; Sheng, Chunyang; Ge, Mingyuan; Chi, Chun-Yung; Cong, Sen; Nakano, Aiichiro; Dapkus, P Daniel; Zhou, Chongwu

    2016-02-23

    Monolithic integration of III-V semiconductors with Si has been pursued for some time in the semiconductor industry. However, the mismatch of lattice constants and thermal expansion coefficients represents a large technological challenge for the heteroepitaxial growth. Nanowires, due to their small lateral dimension, can relieve strain and mitigate dislocation formation to allow single-crystal III-V materials to be grown on Si. Here, we report a facile five-step heteroepitaxial growth of GaAs nanowires on Si using selective area growth (SAG) in metalorganic chemical vapor deposition, and we further report an in-depth study on the twin formation mechanism. Rotational twin defects were observed in the nanowire structures and showed strong dependence on the growth condition and nanowire size. We adopt a model of faceted growth to demonstrate the formation of twins during growth, which is well supported by both a transmission electron microscopy study and simulation based on nucleation energetics. Our study has led to twin-free segments in the length up to 80 nm, a significant improvement compared to previous work using SAG. The achievements may open up opportunities for future functional III-V-on-Si heterostructure devices.

  19. Effect of precursor concentration on the growth of zinc oxide nanorod arrays on pre-treated substrates

    International Nuclear Information System (INIS)

    Urgessa, Z.N.; Oluwafemi, O.S.; Botha, J.R.

    2012-01-01

    Well aligned zinc oxide nanorod arrays (ZNAs) synthesized by a simple chemical bath deposition method were fabricated on pre-treated Si substrates. By keeping the molar VI/II ratio constant, the effect of precursor concentration on the growth and optical quality of the ZNAs was investigated. The as-synthesized ZNAs were characterized by field emission scanning electron microscopy (FESEM), x-ray diffraction (XRD) and photoluminescence spectroscopy (PL). FESEM images show that both the diameter and aspect ratio of the ZNAs increase dramatically as the precursor concentration increases. The XRD analysis indicates that all the as-grown ZNAs are crystalline and are preferentially oriented along the c-axis. The high intensity ratio of the UV emission to visible emission in the room temperature PL spectra illustrate that high optical quality ZNAs were produced.

  20. Effect of precursor concentration on the growth of zinc oxide nanorod arrays on pre-treated substrates

    Energy Technology Data Exchange (ETDEWEB)

    Urgessa, Z.N. [Department of Physics, P.O. Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa); Oluwafemi, O.S., E-mail: oluwafemi.oluwatobi@gmail.com [Department of Chemistry and Chemical Technology, Walter Sisulu University, Mthatha Campus, Private Bag XI, 5117 (South Africa); Botha, J.R. [Department of Physics, P.O. Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa)

    2012-05-15

    Well aligned zinc oxide nanorod arrays (ZNAs) synthesized by a simple chemical bath deposition method were fabricated on pre-treated Si substrates. By keeping the molar VI/II ratio constant, the effect of precursor concentration on the growth and optical quality of the ZNAs was investigated. The as-synthesized ZNAs were characterized by field emission scanning electron microscopy (FESEM), x-ray diffraction (XRD) and photoluminescence spectroscopy (PL). FESEM images show that both the diameter and aspect ratio of the ZNAs increase dramatically as the precursor concentration increases. The XRD analysis indicates that all the as-grown ZNAs are crystalline and are preferentially oriented along the c-axis. The high intensity ratio of the UV emission to visible emission in the room temperature PL spectra illustrate that high optical quality ZNAs were produced.

  1. A Molecular Dynamics Study of the Epitaxial Growth of Metallic Nanoclusters Softly Deposited on Substrates with Very Different Lattice Parameter

    International Nuclear Information System (INIS)

    Jimenez-Saez, J C; Perez-MartIn, A M C; Jimenez-RodrIguez, J J

    2007-01-01

    The soft deposition of Cu and Au clusters on Au(001) and Cu(001) surfaces respectively is studied by constant-temperature molecular-dynamics simulations. The initial shape of the nanoclusters is icosahedral or truncated octahedral (Wulff type). Their number of atoms ranges between 12 and 1289 atoms. Bombardment energy is of the order of a few meV/atom. The atomic interactions are mimicked by a many-body potential based on the tightbinding model. The effect of the temperature as activation to get the complete epitaxy is analysed. We have found that Cu clusters manage to align their {002} planes with the substrate by increasing the temperature. However, there is not epitaxial growth in any case since the lattice becomes bcc or important stacking faults are generated. For Au clusters, the alignment of these planes is practically independent of the temperature

  2. The growth of III-V nitrides heterostructure on Si substrate by plasma-assisted molecular beam epitaxy

    International Nuclear Information System (INIS)

    Beh, K.P.; Yam, F.K.; Chin, C.W.; Tneh, S.S.; Hassan, Z.

    2010-01-01

    This paper reports the growth of InGaN/GaN/AlN epitaxial layer on Si(1 1 1) substrate by utilizing plasma-assisted molecular beam epitaxy (PA-MBE) system. The as-grown film was characterized using high-resolution X-ray diffraction (HR-XRD) and photoluminescence (PL). High work function metals, iridium and gold were deposited on the film as metal contacts and their electrical characteristics at pre- and post-annealing were studied. The structural quality of this film is comparative to the values reported in the literature, and the indium molar fraction is 0.57 by employing Vegard's law. The relatively low yellow band emission signifies the grown film is of high quality. For metal contact studies it was found that the post-annealed sample for 5 min shows good conductivity as compared to the other samples.

  3. Growth dependence of conjugation explains limited plasmid invasion in biofilms: an individual‐based modelling study

    DEFF Research Database (Denmark)

    Merkey, Brian; Lardon, Laurent; Seoane, Jose Miguel

    2011-01-01

    Plasmid invasion in biofilms is often surprisingly limited in spite of the close contact of cells in a biofilm. We hypothesized that this poor plasmid spread into deeper biofilm layers is caused by a dependence of conjugation on the growth rate (relative to the maximum growth rate) of the donor......, we find that invasion of a resident biofilm is indeed limited when plasmid transfer depends on growth, but not so in the absence of growth dependence. Using sensitivity analysis we also find that parameters related to timing (i.e. a lag before the transconjugant can transfer, transfer proficiency...... and scan speed) and spatial reach (EPS yield, conjugal pilus length) are more important for successful plasmid invasion than the recipients' growth rate or the probability of segregational loss. While this study identifies one factor that can limit plasmid invasion in biofilms, the new individual...

  4. The growth of Micrococcus varians by utilizing sugar cane blackstrap molasses as substrate

    Directory of Open Access Journals (Sweden)

    Miranda Luís A. S.

    1999-01-01

    Full Text Available Comparative studies on the growth of Micrococcus varians were carried out in BHI culture medium (control as well as in a culture medium with 2% diluted sugar cane blackstrap molasses, enriched with 0.1% yeast extract. The experiment was conducted with three samples of the experimental and control media in a 5 liter fermentor with working volume of 3.5 liters, continuous agitation (150 rpm, 35 ± 0.1°C temperature, 0.7 L air. l-1 medium. min -1, initial pH 7.0 ± 0.2, 24 hour fermentation period, and approximate inoculum of 6.0 log10 CFU/ml. Samples were collected at 2-hour intervals. Micrococcus varians grew in the two culture media studied, which confirms the experimental medium viability for the growth of this species. The final average concentration of biomass was higher in the control medium than in the experimental medium: 0.99 g.l-1 and 0.78 g.l-1, respectively. The final number of viable cells at the end of fermentation was 20.65 log10 CFU/ml for the control medium (BHI, while in the experimental medium the number of viable cells was 19.43 log10 CFU/ml. The consumption of total sugars was higher for the biomass in the control medium (79.78%, while only 50.53% was consumed for the experimental medium.

  5. ARBUSCULAR MYCORRHIZAL IN THE GROWTH OF LEGUMINOUS TREES ON COALMINE WASTE ENRICHED SUBSTRATE

    Directory of Open Access Journals (Sweden)

    Shantau Camargo Gomes Stoffel

    2016-06-01

    Full Text Available The objective of this work was to evaluate the effects of arbuscular mycorrhizal inoculation in the growth, colonization and absorption of P and trace elements of leguminous trees on coal mine wastes. Independent assays for Mimosa scabrella Benth. (common name bracatinga, Mimosa bimucronata (DC. Kuntze (maricá and Parapiptadenia rigida (Benth. Brenan (angico-vermelho were carried out in a greenhouse on an entirely casualized experimental delineation composed of six treatments. Five coal mine autochthonous arbuscular mycorrhizal fungal isolates were tested, including Acaulospora colombiana, Acaulospora morrowiae, Dentiscutata heterogama, Rhizophagus clarus and Rhizophagus irregulars, aside from a control treatment, with four replications each. Results show that arbuscular mycorrhizal colonization was greater than 60% for Mimosa species, and up to 26% for Parapiptadenia. Overall, the fungal inoculation promoted better plant growth, with increments of up to 1430%. Phosphorous absorption was favored, especially when inoculation was done with A. colombiana, R. irregularis and A. morrowiae. Even though there was a conclusive reduction in the levels of trace elements in the plant´s shoots, the inoculation with those species of fungi promoted significant increments in the accumulated levels of As, Cu, Zn and Cr for all plant species tested. Therefore, arbuscular mycorrhizal fungi play important roles in these poor, degraded and often contaminated environments.

  6. Nitrogen form affects pH and EC of whole pine tree substrate and growth of petunia

    Science.gov (United States)

    Wood-based substrates are potential alternatives or amendments to traditional peat-based and pine bark substrates. Undesirable changes in substrate pH may result from the application of supplemental fertilizer required by some crops grown in wood-based substrates. Experiments were conducted to evalu...

  7. Growth, Structural and Optical Characterization of ZnO Nanotubes on Disposable-Flexible Paper Substrates by Low-Temperature Chemical Method

    Directory of Open Access Journals (Sweden)

    M. Y. Soomro

    2012-01-01

    Full Text Available We report the synthesis of vertically aligned ZnO nanotubes (NTs on paper substrates by low-temperature hydrothermal method. The growth of ZnO NTs on the paper substrate is discussed; further, the structural and optical properties are investigated by scanning electron microscope (SEM, transmission electron microscopy (TEM, X-ray diffraction (XRD, energy-dispersive X-ray spectroscopy (EDS, and cathodoluminescence (CL, and it was found that the ZnO NTs on paper substrate fulfill the structural and optical properties of ZnO NTs grown on other conventional substrates. This will be more beneficial in future usage of ZnO NTs in different fields and applications. Particularly, this approach opens the ways in research and development for high volume manufacturing of low-cost, flexible optoelectronics devices on disposable paper substrates and can be used in the future miniaturization trends.

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

    Energy Technology Data Exchange (ETDEWEB)

    Baidakova, N. A., E-mail: banatale@ipmras.ru [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Bobrov, A. I. [University of Nizhny Novgorod (Russian Federation); Drozdov, M. N.; Novikov, A. V. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Pavlov, D. A. [University of Nizhny Novgorod (Russian Federation); Shaleev, M. V.; Yunin, P. A.; Yurasov, D. V.; Krasilnik, Z. F. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)

    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.

  9. Comparison of different grading schemes in InGaAs metamorphic buffers on GaAs substrate: Tilt dependence on cross-hatch irregularities

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Rahul, E-mail: rkp203@gmail.com [Advanced Technology Development Centre, Indian Institute of Technology, Kharagpur 721302 (India); Bag, Ankush [Advanced Technology Development Centre, Indian Institute of Technology, Kharagpur 721302 (India); Mukhopadhyay, Partha [Rajendra Mishra School of Engineering Entrepreneurship, Indian Institute of Technology, Kharagpur 721302 (India); Das, Subhashis [Advanced Technology Development Centre, Indian Institute of Technology, Kharagpur 721302 (India); Biswas, Dhrubes [Department of Electronics & Electrical Communication Engineering, Indian Institute of Technology, Kharagpur 721 302 (India)

    2015-12-01

    Highlights: • InGaAs graded MBs with different grading scheme has been grown by MBE on GaAs. • Continuously graded MB exhibits smoother surface morphology. • Grading scheme has been found to have little impact on lattice relaxation. • Grading schemeaffects the lattice tilt significantly. • Cross-hatch surface irregularities affect the crystallographic tilt. - Abstract: InGaAs graded metamorphic buffers (MBs) with different grading strategies have been grown by molecular beam epitaxy (MBE) on GaAs (0 0 1) substrate. A detailed comparative analysis of surface using atomic force microscopy (AFM), and bulk properties using high resolution X-ray diffraction (HRXRD) and room temperature photoluminescence (RTPL) of grown MBs have been presented to comprehend the effectiveness of different grading scheme on InGaAs MBs. Conventional, statistical and fractal analysis on measured AFM data has been performed for in-depth investigation of these surfaces. The grading scheme has been found to have little impact on residual strain while it affects the epitaxial tilt significantly. Moreover, the tilt has been found to depend on growth front irregularities. Tilt magnitude in a graded MB has been found to vary with composition while tilt azimuth has been found to be almost same in the graded layers. PL Intensity and a shift in the PL peaks have been used to study the quality of the MB and residual strain comparatively.

  10. Comparison of different grading schemes in InGaAs metamorphic buffers on GaAs substrate: Tilt dependence on cross-hatch irregularities

    International Nuclear Information System (INIS)

    Kumar, Rahul; Bag, Ankush; Mukhopadhyay, Partha; Das, Subhashis; Biswas, Dhrubes

    2015-01-01

    Highlights: • InGaAs graded MBs with different grading scheme has been grown by MBE on GaAs. • Continuously graded MB exhibits smoother surface morphology. • Grading scheme has been found to have little impact on lattice relaxation. • Grading schemeaffects the lattice tilt significantly. • Cross-hatch surface irregularities affect the crystallographic tilt. - Abstract: InGaAs graded metamorphic buffers (MBs) with different grading strategies have been grown by molecular beam epitaxy (MBE) on GaAs (0 0 1) substrate. A detailed comparative analysis of surface using atomic force microscopy (AFM), and bulk properties using high resolution X-ray diffraction (HRXRD) and room temperature photoluminescence (RTPL) of grown MBs have been presented to comprehend the effectiveness of different grading scheme on InGaAs MBs. Conventional, statistical and fractal analysis on measured AFM data has been performed for in-depth investigation of these surfaces. The grading scheme has been found to have little impact on residual strain while it affects the epitaxial tilt significantly. Moreover, the tilt has been found to depend on growth front irregularities. Tilt magnitude in a graded MB has been found to vary with composition while tilt azimuth has been found to be almost same in the graded layers. PL Intensity and a shift in the PL peaks have been used to study the quality of the MB and residual strain comparatively.

  11. Attached biomass growth and substrate utilization rate in a moving bed biofilm reactor

    Directory of Open Access Journals (Sweden)

    J. J. Marques

    2008-12-01

    Full Text Available A moving bed bioreactor containing cubes of polyether foam immersed in a synthetic wastewater (an aqueous mixture of meat extract, yeast extract, dextrose, meat peptone, ammonium chloride, potassium chloride, sodium chloride, sodium bicarbonate, potassium mono-hydrogen-phosphate and magnesium sulphate was used to evaluate bacterial growth and biomass yield parameters based on Monod's equation. The wastewater was supplied in the bottom of the equipment flowing ascending in parallel with a diffused air current that provided the mixing of the reactor content. Suspended and attached biomass concentration was measured through gravimetric methods. Good agreement was found between experimental kinetic parameters values and those obtained by other researchers. The only significant difference was the high global biomass content about 2 times the values obtained in conventional processes, providing high performance with volumetric loading rates up to 5.5 kg COD/m³/d.

  12. Iron-Doped Carbon Aerogels: Novel Porous Substrates for Direct Growth of Carbon Nanotubes

    Science.gov (United States)

    Steiner, S. A.; Baumann, T. F.; Kong, J.; Satcher, J. H.; Dresselhaus, M. S.

    2007-02-20

    We present the synthesis and characterization of Fe-doped carbon aerogels (CAs) and demonstrate the ability to grow carbon nanotubes directly on monoliths of these materials to afford novel carbon aerogel-carbon nanotube composites. Preparation of the Fe-doped CAs begins with the sol-gel polymerization of the potassium salt of 2,4-dihydroxybenzoic acid with formaldehyde, affording K{sup +}-doped gels that can then be converted to Fe{sup 2+}- or Fe{sup 3+}-doped gels through an ion exchange process, dried with supercritical CO{sub 2} and subsequently carbonized under an inert atmosphere. Analysis of the Fe-doped CAs by TEM, XRD and XPS revealed that the doped iron species are reduced during carbonization to form metallic iron and iron carbide nanoparticles. The sizes and chemical composition of the reduced Fe species were related to pyrolysis temperature as well as the type of iron salt used in the ion exchange process. Raman spectroscopy and XRD analysis further reveal that, despite the presence of the Fe species, the CA framework is not significantly graphitized during pyrolysis. The Fe-doped CAs were subsequently placed in a thermal CVD reactor and exposed to a mixture of CH{sub 4} (1000 sccm), H{sub 2} (500 sccm), and C{sub 2}H{sub 4} (20 sccm) at temperatures ranging from 600 to 800 C for 10 minutes, resulting in direct growth of carbon nanotubes on the aerogel monoliths. Carbon nanotubes grown by this method appear to be multiwalled ({approx}25 nm in diameter and up to 4 mm long) and grow through a tip-growth mechanism that pushes catalytic iron particles out of the aerogel framework. The highest yield of CNTs were grown on Fe-doped CAs pyrolyzed at 800 C treated at CVD temperatures of 700 C.

  13. Iron-Doped Carbon Aerogels: Novel Porous Substrates for Direct Growth of Carbon Nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Steiner, S A; Baumann, T F; Kong, J; Satcher, J H; Dresselhaus, M S

    2007-02-15

    We present the synthesis and characterization of Fe-doped carbon aerogels (CAs) and demonstrate the ability to grow carbon nanotubes directly on monoliths of these materials to afford novel carbon aerogel-carbon nanotube composites. Preparation of the Fe-doped CAs begins with the sol-gel polymerization of the potassium salt of 2,4-dihydroxybenzoic acid with formaldehyde, affording K{sup +}-doped gels that can then be converted to Fe{sup 2+}- or Fe{sup 3+}-doped gels through an ion exchange process, dried with supercritical CO{sub 2} and subsequently carbonized under an inert atmosphere. Analysis of the Fe-doped CAs by TEM, XRD and XPS revealed that the doped iron species are reduced during carbonization to form metallic iron and iron carbide nanoparticles. The sizes and chemical composition of the reduced Fe species were related to pyrolysis temperature as well as the type of iron salt used in the ion exchange process. Raman spectroscopy and XRD analysis further reveal that, despite the presence of the Fe species, the CA framework is not significantly graphitized during pyrolysis. The Fe-doped CAs were subsequently placed in a thermal CVD reactor and exposed to a mixture of CH{sub 4} (1000 sccm), H{sub 2} (500 sccm), and C{sub 2}H{sub 4} (20 sccm) at temperatures ranging from 600 to 800 C for 10 minutes, resulting in direct growth of carbon nanotubes on the aerogel monoliths. Carbon nanotubes grown by this method appear to be multiwalled ({approx}25 nm in diameter and up to 4 mm long) and grow through a tip-growth mechanism that pushes catalytic iron particles out of the aerogel framework. The highest yield of CNTs were grown on Fe-doped CAs pyrolyzed at 800 C treated at CVD temperatures of 700 C.

  14. Growth and xanthan production of Xanthomonas campestris depending on the N-source concentration

    Energy Technology Data Exchange (ETDEWEB)

    Prell, A [Academy of Sciences of the Czech Republic, Prague (Czech Republic). Inst. of Microbiology; Lasik, J [Academy of Sciences of the Czech Republic, Prague (Czech Republic). Inst. of Microbiology; Konicek, J [Academy of Sciences of the Czech Republic, Prague (Czech Republic). Inst. of Microbiology; Sobotka, M [Academy of Sciences of the Czech Republic, Prague (Czech Republic). Inst. of Microbiology; Sys, J [Academy of Sciences of the Czech Republic, Prague (Czech Republic). Inst. of Microbiology

    1995-11-01

    Growth of X. campestris and production of xanthan were studied in several batch fermentations with different starting concentrations of N-source. The dependencies of growth, productivity and yields on initial N-source concentration were observed. The maximum yields in the course of cultivations were identified. (orig.)

  15. A simple equation for describing the temperature dependent growth of free-floating macrophytes

    NARCIS (Netherlands)

    Heide, van Tj.; Roijackers, R.M.M.; Nes, van E.H.; Peeters, E.T.H.M.

    2006-01-01

    Temperature is one of the most important factors determining growth rates of free-floating macrophytes in the field. To analyse and predict temperature dependent growth rates of these pleustophytes, modelling may play an important role. Several equations have been published for describing

  16. Plasmin-driven fibrinolysis facilitates skin tumor growth in a gender-dependent manner

    DEFF Research Database (Denmark)

    Hald, Andreas; Eickhardt, Hanne; Maerkedahl, Rasmus Baadsgaard

    2012-01-01

    deficiency was due to thrombosis and lost patency of the tumor vasculature, resulting in tumor necrosis. The connection between plasmin-dependent fibrinolysis, vascular patency, and tumor growth was further substantiated as the effect of plasminogen deficiency on tumor growth could be reverted...

  17. Magnetophotoluminescence study of the influence of substrate orientation and growth interruption on the electronic properties of InAs/GaAs quantum dots

    International Nuclear Information System (INIS)

    Godefroo, S.; Maes, J.; Hayne, M.; Moshchalkov, V.V.; Henini, M.; Pulizzi, F.; Patane, A.; Eaves, L.

    2004-01-01

    We have used photoluminescence in pulsed (≤50 T) and dc (≤12 T) magnetic fields to investigate the influence of substrate orientation and growth interruption (GI) on the electronic properties of InAs/GaAs quantum dots, grown by molecular beam epitaxy at 480 deg. C. Dot formation is very efficient on the (100) substrate: electronic confinement is already strong without GI and no significant change in confinement is observed with GI. On the contrary, for the (311)B substrate strong confinement of the charges only occurs after a GI is introduced. When longer GIs are applied the dots become higher

  18. The hemicellulolytic enzyme arsenal of Thermobacillus xylanilyticus depends on the composition of biomass used for growth

    Directory of Open Access Journals (Sweden)

    Rakotoarivonina Harivony

    2012-12-01

    Full Text Available Abstract Background Thermobacillus xylanilyticus is a thermophilic and highly xylanolytic bacterium. It produces robust and stable enzymes, including glycoside hydrolases and esterases, which are of special interest for the development of integrated biorefineries. To investigate the strategies used by T. xylanilyticus to fractionate plant cell walls, two agricultural by-products, wheat bran and straw (which differ in their chemical composition and tissue organization, were used in this study and compared with glucose and xylans. The ability of T. xylanilyticus to grow on these substrates was studied. When the bacteria used lignocellulosic biomass, the production of enzymes was evaluated and correlated with the initial composition of the biomass, as well as with the evolution of any residues during growth. Results Our results showed that T. xylanilyticus is not only able to use glucose and xylans as primary carbon sources but can also use wheat bran and straw. The chemical compositions of both lignocellulosic substrates were modified by T. xylanilyticus after growth. The bacteria were able to consume 49% and 20% of the total carbohydrates in bran and straw, respectively, after 24 h of growth. The phenolic and acetyl ester contents of these substrates were also altered. Bacterial growth on both lignocellulosic biomasses induced hemicellulolytic enzyme production, and xylanase was the primary enzyme secreted. Debranching activities were differentially produced, as esterase activities were more important to bacterial cultures grown on wheat straw; arabinofuranosidase production was significantly higher in bacterial cultures grown on wheat bran. Conclusion This study provides insight into the ability of T. xylanilyticus to grow on abundant agricultural by-products, which are inexpensive carbon sources for enzyme production. The composition of the biomass upon which the bacteria grew influenced their growth, and differences in the biomass provided

  19. Substrate Dependent Ad-Atom Migration on Graphene and the Impact on Electron-Beam Sculpting Functional Nanopores.

    Science.gov (United States)

    Freedman, Kevin J; Goyal, Gaurav; Ahn, Chi Won; Kim, Min Jun

    2017-05-10

    The use of atomically thin graphene for molecular sensing has attracted tremendous attention over the years and, in some instances, could displace the use of classical thin films. For nanopore sensing, graphene must be suspended over an aperture so that a single pore can be formed in the free-standing region. Nanopores are typically drilled using an electron beam (e-beam) which is tightly focused until a desired pore size is obtained. E-beam sculpting of graphene however is not just dependent on the ability to displace atoms but also the ability to hinder the migration of ad-atoms on the surface of graphene. Using relatively lower e-beam fluxes from a thermionic electron source, the C-atom knockout rate seems to be comparable to the rate of carbon ad-atom attraction and accumulation at the e-beam/graphene interface (i.e., R knockout ≈ R accumulation ). Working at this unique regime has allowed the study of carbon ad-atom migration as well as the influence of various substrate materials on e-beam sculpting of graphene. We also show that this information was pivotal to fabricating functional graphene nanopores for studying DNA with increased spatial resolution which is attributed to atomically thin membranes.

  20. In situ study of the growth and degradation processes in tetragonal lysozyme crystals on a silicon substrate by high-resolution X-ray diffractometry

    Science.gov (United States)

    Kovalchuk, M. V.; Prosekov, P. A.; Marchenkova, M. A.; Blagov, A. E.; D'yakova, Yu. A.; Tereshchenko, E. Yu.; Pisarevskii, Yu. V.; Kondratev, O. A.

    2014-09-01

    The results of an in situ study of the growth of tetragonal lysozyme crystals by high-resolution X-ray diffractometry are considered. The crystals are grown by the sitting-drop method on crystalline silicon substrates of different types: both on smooth substrates and substrates with artificial surface-relief structures using graphoepitaxy. The crystals are grown in a special hermetically closed crystallization cell, which enables one to obtain images with an optical microscope and perform in situ X-ray diffraction studies in the course of crystal growth. Measurements for lysozyme crystals were carried out in different stages of the crystallization process, including crystal nucleation and growth, developed crystals, the degradation of the crystal structure, and complete destruction.

  1. GROWTH AND NUTRITIONAL ANALYSIS OF TREE SPECIES IN CONTAMINATED SUBSTRATE BY LEACHABLE HERBICIDES

    Directory of Open Access Journals (Sweden)

    Rebecca de Araújo Fiore

    Full Text Available ABSTRACT Ecosystems contamination by residues of pesticides requires special attention to the herbicides subject to leaching. The objective was to select tree species to rhizodegradation contaminated by residues of 2,4-D and atrazine and to recompose riparian areas to agricultural fields, then reducing the risk of contamination of water courses. A total of 36 treatments consisted of the combinations of forest species were evaluated [Inga marginata (Inga, Schizolobium parahyba (guapuruvu, Handroanthus serratifolius (ipê amarelo, Jacaranda puberula (carobinha, Cedrela fissilis (cedro, Calophyllum brasiliensis (landin, Psidium mirsinoides (goiabinha, Tibouchina glandulosa (quaresmeira, Caesalpinia férrea (pau-ferro, Caesalpinia pluviosa (sibipiruna, Terminalia argêntea (capitão and Schinopsis brasiliensis (braúna] and three solutions simulating leachate compound (atrazine, 2,4-D and water - control, with four replicates each. The characteristics measured were plant height, stem diameter, number of leaves, leaf area and dry biomass, and foliar nutrition. Forest species survived the herbicide application, and most showed an increase in macronutrients even under an herbicide application, and the Inga had the highest tolerance regarding growth analysis. It is recommended to use species that are more tolerant to Atrazine and 2,4-D in field experiments to confirm previous results of this simulation.

  2. Alginate as a cell culture substrate for growth and differentiation of human retinal pigment epithelial cells.

    Science.gov (United States)

    Heidari, Razeih; Soheili, Zahra-Soheila; Samiei, Shahram; Ahmadieh, Hamid; Davari, Maliheh; Nazemroaya, Fatemeh; Bagheri, Abouzar; Deezagi, Abdolkhalegh

    2015-03-01

    The purpose of this study was to evaluate retinal pigment epithelium (RPE) cells' behavior in alginate beads that establish 3D environment for cellular growth and mimic extracellular matrix versus the conventional 2D monolayer culture. RPE cells were encapsulated in alginate beads by dripping alginate cell suspension into CaCl2 solution. Beads were suspended in three different media including Dulbecco's modified Eagle's medium (DMEM)/F12 alone, DMEM/F12 supplemented with 10 % fetal bovine serum (FBS), and DMEM/F12 supplemented with 30 % human amniotic fluid (HAF). RPE cells were cultivated on polystyrene under the same conditions as controls. Cell phenotype, cell proliferation, cell death, and MTT assay, immunocytochemistry, and real-time RT-PCR were performed to evaluate the effect of alginate on RPE cells characteristics and integrity. RPE cells can survive and proliferate in alginate matrixes. Immunocytochemistry analysis exhibited Nestin, RPE65, and cytokeratin expressions in a reasonable number of cultured cells in alginate beads. Real-time PCR data demonstrated high levels of Nestin, CHX10, RPE65, and tyrosinase gene expressions in RPE cells immobilized in alginate when compared to 2D monolayer culture systems. The results suggest that alginate can be used as a reliable scaffold for maintenance of RPE cells' integrity and in vitro propagation of human retinal progenitor cells for cell replacement therapies in retinal diseases.

  3. Direct in Situ Conversion of Metals into Metal-Organic Frameworks: A Strategy for the Rapid Growth of MOF Films on Metal Substrates.

    Science.gov (United States)

    Ji, Hoon; Hwang, Sunhyun; Kim, Keonmok; Kim, CheolGi; Jeong, Nak Cheon

    2016-11-30

    The fabrication of metal-organic framework (MOF) films on conducting substrates has demonstrated great potential in applications such as electronic conduction and sensing. For these applications, direct contact of the film to the conducting substrate without a self-assembled monolayer (SAM) is a desired step that must be achieved prior to the use of MOF films. In this report, we propose an in situ strategy for the rapid one-step conversion of Cu metal into HKUST-1 films on conducting Cu substrates. The Cu substrate acts both as a conducting substrate and a source of Cu 2+ ions during the synthesis of HKUST-1. This synthesis is possible because of the simultaneous reaction of an oxidizing agent and a deprotonating agent, in which the former agent dissolves the metal substrate to form Cu 2+ ions while the latter agent deprotonates the ligand. Using this strategy, the HKUST-1 film could not only be rapidly synthesized within 5 min but also be directly attached to the Cu substrate. Based on microscopic studies, we propose a plausible mechanism for the growth reaction. Furthermore, we show the versatility of this in situ conversion methodology, applying it to ZIF-8, which comprises Zn 2+ ions and imidazole-based ligands. Using an I 2 -filled HKUST-1 film, we further demonstrate that the direct contact of the MOF film to the conducting substrate makes the material more suitable for use as a sensor or electronic conductor.

  4. Profiling of Substrates for Zinc‐dependent Lysine Deacylase Enzymes: HDAC3 Exhibits Decrotonylase Activity In Vitro

    DEFF Research Database (Denmark)

    Madsen, Andreas Stahl; Olsen, Christian Adam

    2012-01-01

    Ein systematisches Screening der Aktivitäten der elf humanen zinkabhängigen Lysin-Deacylasen gegen eine Reihe fluorogener Substrate (siehe Schema) ergab wiederum geeignete Substrate für Screenings der Histon-Deacetylasen HDAC10 und HDAC11. Darüber hinaus wurde gefunden, dass HDAC3 im Komplex mit...

  5. The properties of TiN ultra-thin films grown on SiO{sub 2} substrate by reactive high power impulse magnetron sputtering under various growth angles

    Energy Technology Data Exchange (ETDEWEB)

    Shayestehaminzadeh, S., E-mail: ses30@hi.is [Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavik (Iceland); Tryggvason, T.K. [Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavik (Iceland); Karlsson, L. [School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, 28759 Bremen (Germany); Olafsson, S. [Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavik (Iceland); Gudmundsson, J.T. [Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavik (Iceland); University of Michigan-Shanghai Jiao Tong University, University Joint Institute, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240 (China)

    2013-12-02

    Thin TiN films were grown on SiO{sub 2} by reactive high power impulse magnetron sputtering (HiPIMS) and conventional dc magnetron sputtering (dcMS) while varying the angle between the target and the substrate surface from 0° (on-axis growth) to 90° (off-axis growth). Surface morphology and structural characterization were carried out using X-ray diffraction and reflection methods and the film properties were compared. The dcMS process shows higher growth rate than the HiPIMS process for on-axis grown films but the dcMS growth rate drops drastically for off-axis growth while the HiPIMS growth rate decreases slowly with increased angle between target and substrate for off-axis growth and becomes comparable to the dcMS growth rate. The dcMS grown films exhibit angle dependence in the density and surface roughness while the HiPIMS process creates denser and smoother films that are less angle dependent in all aspects. It was observed that the HiPIMS grown films remain poly-crystalline for all angles of rotation while the dcMS grown films are somewhat amorphous after 60°. The [111] and [200] grain sizes are comparable to the total film thickness in the HiPIMS grown films for all angles of rotation. In the case of dcMS, the [111], [200] and [220] grain sizes are roughly of the same size and much smaller than the total thickness for all growth angles except at 60° and higher. - Highlights: • TiN films were grown on SiO{sub 2} by HiPIMS and dcMS under various growth angles. • Influence of growth angle α = 0–90° on deposition rate and film quality was studied. • The HiPIMS process produces denser and smoother films for all growth angles. • At α = 0°, the growth rate of HiPIMS is 25% of dcMS while it is 50% at 90°. • The HiPIMS grown films remain poly-crystalline for all growth angles.

  6. Schottky barrier diode based on β-Ga2O3 (100) single crystal substrate and its temperature-dependent electrical characteristics

    Science.gov (United States)

    He, Qiming; Mu, Wenxiang; Dong, Hang; Long, Shibing; Jia, Zhitai; Lv, Hangbing; Liu, Qi; Tang, Minghua; Tao, Xutang; Liu, Ming

    2017-02-01

    The Pt/β-Ga2O3 Schottky barrier diode and its temperature-dependent current-voltage characteristics were investigated for power device application. The edge-defined film-fed growth (EFG) technique was utilized to grow the (100)-oriented β-Ga2O3 single crystal substrate that shows good crystal quality characterized by X-ray diffraction and high resolution transmission electron microscope. Ohmic and Schottky electrodes were fabricated by depositing Ti and Pt metals on the two surfaces, respectively. Through the current-voltage (I-V) measurement under different temperature and the thermionic emission modeling, the fabricated Pt/β-Ga2O3 Schottky diode was found to show good performances at room temperature, including rectification ratio of 1010, ideality factor (n) of 1.1, Schottky barrier height (ΦB) of 1.39 eV, threshold voltage (Vbi) of 1.07 V, ON-resistance (RON) of 12.5 mΩ.cm2, forward current density at 2 V (J@2V) of 56 A/cm2, and saturation current density (J0) of 2 × 10-16 A/cm2. The effective donor concentration Nd - Na was calculated to be about 2.3 × 1014 cm3. Good temperature dependent performance was also found in the device. The Schottky barrier height was estimated to be about 1.3 eV-1.39 eV at temperatures ranging from room temperature to 150 °C. With increasing temperature, parameters such as RON and J@2V become better, proving that the diode can work well at high temperature. The EFG grown β-Ga2O3 single crystal is a promising material to be used in the power devices.

  7. Calcium-dependent isolation of the 36-kilodalton substrate of pp60/sup src/-kinase. Fractionation of the phosphorylated and unphosphorylated species

    International Nuclear Information System (INIS)

    Soric, J.; Gordon, J.A.

    1986-01-01

    In this paper, the authors present a new and simple purification of the 36-kDa protein, a major substrate of both viral and growth factor-receptor associated tyrosine protein kinases, and its complex from normal and Schmidt-Ruppin strain Rous sarcoma virus-transformed chicken embryo fibroblasts that employs a DEAE-Sephacel column and introduces the calcium-dependent adsorption of 36-kDa protein. The use of EGTA step gradients differentially elutes the 36-kDa molecules from the DEAE-Sephacel column. An average total yield of the 36-kDa protein in all fractions approached 80% and represented 0.78% of the [ 35 S]methionine-labeled cellular protein. A purity of 95-99% was obtained with a yield of 60% in the central elution fractions from normal or Rous sarcoma virus-transformed chicken embryo fibroblasts. Furthermore, 2 mM EGTA elutes poorly phosphorylated molecules while heavily phosphorylated 36-kDa protein requires 4 or 6 M EGTA; a small residual fraction is released at 8-10 mM EGTA. If the EGTA step gradients were neutralized with Ca 2+ ion, elution of the 36-kDa protein is inhibited. Tyrosine phosphorylation of the 36-kDa protein is increased 2-3-fold following a short term incubation of whole cells with micromolar vanadate. The elution pattern (but not intensity) of the 36-kDa protein obtained from lysates of vanadate-treated cells was identical to untreated cell lysates. The additional phosphorylation appears to result from a recruitment of unphosphorylated 36-kDa protein as the position (but not intensity) of the phosphorylated tryptic peptides is unchanged. They conclude that the function of the 36-kDa protein may be calcium ion-dependent and may be influenced by the phosphorylation state of the protein

  8. Sunflower seed for human consumption as a substrate for the growth of mycopopulations

    Directory of Open Access Journals (Sweden)

    Škrinjar Marija M.

    2012-01-01

    Full Text Available These mycological investigations are implicating samples of protein sunflower seed from regular cultivation in the Vojvodina Province. Samples are examined in different stages of production: reception in the silo, separation of massive fraction on peeler and then peeling, kernel after peeling, hull, final product, i.e. kernels separated from visible impurities on conveyor bel, that are later manually divided in two fractions - a seemingly whole, undamaged kernels, without change of colour, and b seemingly damaged kernels, broken, with change of colour. For the determination of viable count of moulds and their isolation, two different media are used in parallel: Sabouraud maltose agar (SMA and malt/yeast extract with 50% of glucose (MY50G, favourable for growth of xerophilic moulds. All samples tested were contaminated with fungi. Total viable mould count per seed varied from 1.6 (SMA respecting 1.3 (MY50G on reception, to 5.6 (SMA and 7.5 (MY50G cfu/seed in visually damaged sunflower kernels (final product. From seeds, kernels and hull, numerous moulds were isolated, belonging to 8 genera and 13 species (Alternaria alternata, Arthrinium phaeospermum, Aspergillus candidus, A. flavus, A. niger, A. ochraceus, A. versicolor, A. wentii, Cladosporium cladosporioides, Eurotium herbariorum, Penicillium aurantiogriseum, Rhizopus stolonifer and Trichoderma harzianum. Alternaria alternata, Aspergillus flavus, A.ochraceus, A. versicolor and Eurotium herbariorum were isolated on both media. Aspergillus candidus, A. versicolor, C. Cladosporioides, P. aurantiogriseum and T. harzianum were isolated only on SMA, while A. niger, A. wentii and R. stolonifer were exclusively isolated on MY50G. Most ubiquitous species is A. alternata, which is isolated from all tested samples, while A. candidus, C. cladosporioides and T. harzianum were isolated from sunflower seed on reception in silo, using SMA medium.

  9. Neutrino masses, scale-dependent growth, and redshift-space distortions

    Energy Technology Data Exchange (ETDEWEB)

    Hernández, Oscar F., E-mail: oscarh@physics.mcgill.ca [Marianopolis College, 4873 Westmount Ave., Westmount, QC H3Y 1X9 (Canada)

    2017-06-01

    Massive neutrinos leave a unique signature in the large scale clustering of matter. We investigate the wavenumber dependence of the growth factor arising from neutrino masses and use a Fisher analysis to determine the aspects of a galaxy survey needed to measure this scale dependence.