204 research outputs found

    A Facile Synthesis of Polypyrrole/Carbon Nanotube Composites with Ultrathin, Uniform and Thickness-Tunable Polypyrrole Shells

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    An improved approach to assemble ultrathin and thickness-tunable polypyrrole (PPy) films onto multiwall carbon nanotubes (MWCNTs) has been investigated. A facile procedure is demonstrated for controlling the morphology and thickness of PPy film by adding ethanol in the reaction system and a possible mechanism of the coating formation process is proposed. The coated PPy films can be easily tuned by adding ethanol and adjusting a mass ratio of pyrrole to MWCNTs. Moreover, the thickness of PPy significantly influences the electronic conductivity and capacitive behavior of the PPy/MWCNT composites. The method may provide a facile strategy for tailoring the polymer coating on carbon nanotubes (CNTs) for carbon-based device applications

    Uso de Plasma Seminal en la Criopreservación de Espermatozoides Epididimarios de Equinos

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    Equine seminal plasma was used in a lactose-EDTA extender for cryopreservation of equine epididymal sperm. Twelve pairs of testicles of slaughtered horses were used. Epididymides were separated and washed applying the retrograde technique to obtain sperm by injecting 10 ml of lactose-EDTA extender through the vas deferens. Samples with more than 30% motility were used. Samples were diluted 1: 1 with the lactose-EDTAextender seminal plasma and filled into 0.5 ml straws at a concentration of 386.3 x 106, frozen in liquid nitrogen and stored for 10 days. The values for fresh and thawed samples were: motility: 43.3 and 16.4% (p<0.05), viability: 48.3 and 40.5%, normal morphology: 67.1 and 56.5%, and integrity of the plasma membrane (HOS): 48.3 and 45.5%.Se utilizó plasma seminal equino en un dilutor de lactosa-EDTA para la criopreservación de espermatozoides epididimarios de equinos. Se trabajó con 12 pares de testículos de caballos beneficiados. Se separaron los epidídimos y se utilizó la técnica de lavado retrógrado para obtener los espermatozoides, inyectando 10 ml del dilutor lactosa-EDTA por el conducto deferente. Se utilizaron las muestras con más de 30% de motilidad progresiva. Las muestras fueron diluidas 1:1 con el diluyente lactosa-EDTA-plasma seminal y se envasó en pajillas de 0.5 ml a una concentración 386.3 x 106, y fueron congeladas en nitrógeno líquido y almacenadas por 10 días. Los valores obtenidos para las muestras frescas y descongeladas fueron: motilidad progresiva: 43.3 y 16.4% (p<0.05), viabilidad: 48.3 y 40.5%, morfología normal: 67.1 y 56.5%, e integridad de la membrana plasmática (HOS): 48.3 y 45.5%

    Riding over the Kuroshio from the South to the East China Sea: Mixing and transport of DIC

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    Export of dissolved inorganic carbon (DIC) to adjoining oceans enhances the potential of CO2 sequestration in marginal seas. By using a series of measured DIC depth profiles and reported flow transports, we estimated that the intermediate outflow (100-600 m) from the South China Sea is capable of transporting 6.5 +/- 4.1 Tg (1 Tg = 10(12) g) of biologically mediated carbon (DICbio) annually to the East China Sea (ECS) via the northwardly flowing Kuroshio current. The mixing and transport of these DIC-rich waters would raise 3% and 16% of DIC/TA ratio and the Revelle factor of the adjoining seawaters, respectively. Upon upwelling onto the ECS shelf, these DIC-rich waters would counteract the potential of CO2 uptake of shelf waters that might have been enhanced by the accompanying increase in nutrient inputs, thus complicating assessment of the ECS as a net CO2 source or sink. Citation: Sheu, D. D., W.-C. Chou, C. T. A. Chen, C.-L. Wei, H.-L. Hsieh, W.-P. Hou, and M. Dai (2009), Riding over the Kuroshio from the South to the East China Sea: Mixing and transport of DIC, Geophys. Res. Lett., 36, L07603, doi:10.1029/2008GL037017.National Science Council (Taiwan) [NSC-95-2611-M-110-003, NSC-96-2611-M-110-004

    Characterization of complete genome sequence of the spring viremia of carp virus isolated from common carp (Cyprinus carpio) in China

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    The complete genome of spring viraemia of carp virus (SVCV) strain A-1 isolated from cultured common carp (Cyprinus carpio) in China was sequenced and characterized. Reverse transcription-polymerase chain reaction (RT-PCR) derived clones were constructed and the DNA was sequenced. It showed that the entire genome of SVCV A-1 consists of 11,100 nucleotide base pairs, the predicted size of the viral RNA of rhabdoviruses. However, the additional insertions in bp 4633-4676 and bp 4684-4724 of SVCV A-1 were different from the other two published SVCV complete genomes. Five open reading frames (ORFs) of SVCV A-1 were identified and further confirmed by RT-PCR and DNA sequencing of their respective RT-PCR products. The 5 structural proteins encoded by the viral RNA were ordered 3'-N-P-M-G-L-5'. This is the first report of a complete genome sequence of SVCV isolated from cultured carp in China. Phylogenetic analysis indicates that SVCV A-1 is closely related to the members of the genus Vesiculovirus, family Rhabdoviridae.The complete genome of spring viraemia of carp virus (SVCV) strain A-1 isolated from cultured common carp (Cyprinus carpio) in China was sequenced and characterized. Reverse transcription-polymerase chain reaction (RT-PCR) derived clones were constructed and the DNA was sequenced. It showed that the entire genome of SVCV A-1 consists of 11,100 nucleotide base pairs, the predicted size of the viral RNA of rhabdoviruses. However, the additional insertions in bp 4633-4676 and bp 4684-4724 of SVCV A-1 were different from the other two published SVCV complete genomes. Five open reading frames (ORFs) of SVCV A-1 were identified and further confirmed by RT-PCR and DNA sequencing of their respective RT-PCR products. The 5 structural proteins encoded by the viral RNA were ordered 3'-N-P-M-G-L-5'. This is the first report of a complete genome sequence of SVCV isolated from cultured carp in China. Phylogenetic analysis indicates that SVCV A-1 is closely related to the members of the genus Vesiculovirus, family Rhabdoviridae

    Efectos de campos magnéticos en el metabolismo y crecimiento de Lactobacillus Plantarum

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    En la presente investigación se realizaron el cultivo microbiológico de Lactobacillus plantarum y de preparación de los sistemas de generación de campo magnético alterno de hasta 53 kHz. Se logró determinar la influencia del campo magnético variable sobre el crecimiento del Lactobacillus plantarum, observado en las muestras sometidas a campo en tiempos cortos con mediana frecuencia produciendo un aumento en el número de unidades formadoras de colonias - UFC, aproximadamente en un 70 % más comparado con las muestras control. Para el recuento bacteriano se utilizó agar Plate count marca Merck empleando el método de diseminación en placas de Agar. Para la generación de los campos de inducción magnética de distinta frecuencia, se diseñó, construyo y probo cinco bobinas tipo Helmholtz de diferentes características que producían campos magnéticos estables de hasta 60 KHz. en el orden de los miliGauss. La bobina utilizada en la presente investigación tiene un resistencia óhmica de 4.2 ohm y una inductancia de 0,345 mH con 140 espiras bifilar con un alambre awg # 23

    The Social Network: How People with Visual Impairment use Mobile Phones in Kibera, Kenya

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    Living in an informal settlement with a visual impairment can be very challenging resulting in social exclusion. Mobile phones have been shown to be hugely beneficial to people with sight loss in formal and high-income settings. However, little is known about whether these results hold true for people with visual impairment (VIPs) in informal settlements. We present the findings of a case study of mobile technology use by VIPs in Kibera, an informal settlement in Nairobi. We used contextual interviews, ethnographic observations and a co-design workshop to explore how VIPs use mobile phones in their daily lives, and how this use influences the social infrastructure of VIPs. Our findings suggest that mobile technology supports and shapes the creation of social infrastructure. However, this is only made possible through the existing support networks of the VIPs, which are mediated through four types of interaction: direct, supported, dependent and restricted

    Electrical properties of B-doped polycrystalline silicon thin films prepared by rapid thermal chemical vapour deposition

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    In this paper, about 30 mu m thick B-doped polycrystalline silicon (poly-Si) thin films were deposited on quartz substrates, n-type single crystalline silicon wafers and p(++)-type poly-Si ribbons by a rapid thermal chemical vapour deposition system in a temperature range from 1000 to 1150 degrees C. Activation energy measurement and room temperature/temperature dependent Hall effect measurement were performed on the poly-Si thin films prepared on the former two kinds of substrates, respectively. It seems that the electrical properties of as-prepared poly-Si thin films could be qualitatively explained by Seto's grain boundary (GB) trapping theory although there is a big difference between our samples and Seto's in gain size and film thickness etc. The experimental results reconfirm that GB itself is a kind of most effective recombination center with trapping level near the midgap and trapping state density in the order of 1012 cm(-2) magnitude. Electron beam induced current measurements on the poly-Si thin films prepared on the poly-Si ribbons also show that severe recombination occurs at the positions of GBs. (c) 2005 Elsevier B.V All rights reserved

    A Gravity Model Integrating Land-Use and Transportation Policies for Sustainable Development: Case Study of Fresno, California

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    ZSB12017-SJAUXCA-MTI-2222The idea of urban compaction has been long proposed and promoted to address the problem of urban sprawl in many American cities. However, successful cases of implementation in this regard are still rare in the United States. This study uses a classic gravity model, TELUM (Transportation, Economic, and Land-Use Model) to examine the extent to which a land-use or transportation policy must be regulated to make the urban compaction occur in a typical auto-dependent city\u2014Fresno, California. Five scenarios are considered (BL, L1, L2, T1, and T2), in which the baseline (BL) is a natural growth scenario. Without any policy interventions, the city will inevitably expand outward. The L1 (high-intensity zoning) and L2 (growth boundary) results suggest that high-density zoning and growth boundary policies could enable the compaction. The T1 (location impedance) and T2 (carbon tax) results reveal that transportation interventions would create barriers among regions/areas and therefore should be carefully used for compaction. This study not only adds to the literature on urban modeling but also contributes to the practice of smart growth or new urbanism policies for sustainability
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