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111.
Fabrication of liquid crystalline (LC) nanomaterials in an aligned pattern along the multiwalled carbon nanotubes (CNT) has been reported here. The nanocomposite was prepared by sonicating esterified CNTs and the ferroelectric liquid crystal (FLC) in chloroform. The nanohybrid shish kebab (NHSK) like pattern was observed in SEM analysis. The nanocomposite materials were characterized by Fourier transform infrared spectroscopy (FTIR), polarizing optical microscopy and electron microscopy. The DC and AC electrical properties of the composite materials were investigated. The DC conductivity of the nanocomposite increased by 2 order from the FLC materials and AC relaxation has been observed, in the nanocomposite, which was totally absent in the FLC materials. 相似文献
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Expression of IL-10 as a transgene inhibits murine mammary tumor growth and metastasis. Using differential display methodology, we sought genes whose expression was modulated by IL-10. We compared mRNA isolated from parental murine mammary 66.1 tumors, as well as tumors derived from neo(r)-transfected cells and 6 different IL-10-expressing cell lines. We identified 2 cDNA products that were up-regulated in all 6 IL-10-expressing tumors in comparison to parental and 66-neo tumors. One cDNA corresponds to the murine guanylate-binding protein gene Gbp-1/Mag-1. The other cDNA corresponds to the chemokine Mig-1 (monokine induced by IFN-gamma). Both genes were originally identified in IFN-gamma-activated macrophages or macrophage cell lines. We now report that cultured mammary epithelial tumor cell lines also express both genes in response to treatment with IFN-gamma and LPS. Furthermore, IFN-gamma mRNA is elevated in IL-10-expressing tumors in comparison with parental or neo-transfected tumors. Thus, high-level expression of IL-10 as a transgene results in activation rather than suppression of IFN-gamma as well as 2 IFN-gamma-inducible genes. Up-regulation of host IFN-gamma is critical to anti-tumor activity since IL-10 no longer inhibits tumor growth in hosts with a deletion in the IFN-gamma gene. Additionally, Gbp-1/Mag-1 and Mig-1 gene induction no longer occur in IFN-gamma mutant mice. 相似文献
114.
Mriganka Sadhukhan Manas Kumar Kundu Tanmay Bhowmik Sudip Barman 《International Journal of Hydrogen Energy》2017,42(15):9371-9383
Finding efficient electrocatalyst for oxidation of small organic molecules such as methanol (CH3OH), formic acid (HCOOH), formaldehyde (HCHO) etc. is essential for the development of their respective direct fuel cells. We report here highly dispersed platinum nanoparticles (PtNPs) on carbon nitride (CNx) were successfully synthesized by the ultrasound mediated sodium borohydride reduction of H2PtCl6 in presence of CNx nanosheets. This platinum–carbon nitride (Pt/CNx) composite exhibited superior electrocatalytic activity towards oxidation of CH3OH, HCOOH and HCHO in acid media. The mass activity, onset potential, tolerance to carbon monoxide (CO) poisoning and long term durability for the catalytic oxidation of CH3OH, HCOOH, HCHO on Pt/CNx catalyst in acid media is much higher than that of commercial Pt/C catalyst. The mass activity of Pt/CNx catalyst at ~0.64 V (forward scan) is 310 mA/mgPt which is 2.7 time higher than that of commercial Pt/C for methanol oxidation. The electrooxidation of HCOOH on Pt/CNx occurs via dual mechanism with greatly enhanced oxidation through dehydrogenation pathway in comparison with commercial Pt/C. The mass activity on Pt/CNx at 0.3 V (vs. NHE) is 25 times higher than that of Pt/C for oxidation of HCOOH. The superior catalytic activity and durability of this Pt/CNx catalyst can be attributed to high dispersion of PtNPs and strong catalyst support interaction. 相似文献
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A new class of nanocrystal quantum dot (NQD), the "giant" NQD (g-NQD), was investigated for its potential to address outstanding issues associated with the use of NQDs as down-conversion phosphors in light-emitting devices, namely, insufficient chemical/photostability and extensive self-reabsorption when packed in high densities or in thick films. Here, we demonstrate that g-NQDs afford significantly enhanced operational stability compared to their conventional NQD counterparts and minimal self-reabsorption losses. The latter results from a characteristic large Stokes shift (>100 nm; >0.39 eV), which itself is a manifestation of the internal structure of these uniquely thick-shelled NQDs. In carefully prepared g-NQDs, light absorption occurs predominantly in the shell but emission occurs exclusively from the core. We directly compare for the first time the processes of shell→core energy relaxation and core→core energy transfer by evaluating CdS→CdSe down-conversion of blue→red light in g-NQDs and in a comparable mixed-NQD (CdSe and CdS) thin film, revealing that the internal energy relaxation process affords a more efficient and color-pure conversion of blue to red light compared to energy transfer. Lastly, we demonstrate the facile fabrication of white-light devices with correlated color temperature tuned from ~3200 to 5800 K. 相似文献
118.
Kratz K Narasimhan A Tangirala R Moon S Revanur R Kundu S Kim HS Crosby AJ Russell TP Emrick T Kolmakov G Balazs AC 《Nature nanotechnology》2012,7(2):87-90
Nanoparticles have useful properties, but it is often important that they only start working after they are placed in a desired location. The encapsulation of nanoparticles allows their function to be preserved until they are released at a specific time or location, and this has been exploited in the development of self-healing materials and in applications such as drug delivery. Encapsulation has also been used to stabilize and control the release of substances, including flavours, fragrances and pesticides. We recently proposed a new technique for the repair of surfaces called 'repair-and-go'. In this approach, a flexible microcapsule filled with a solution of nanoparticles rolls across a surface that has been damaged, stopping to repair any defects it encounters by releasing nanoparticles into them, then moving on to the next defect. Here, we experimentally demonstrate the repair-and-go approach using droplets of oil that are stabilized with a polymer surfactant and contain CdSe nanoparticles. We show that these microcapsules can find the cracks on a surface and selectively deliver the nanoparticle contents into the crack, before moving on to find the next crack. Although the microcapsules are too large to enter the cracks, their flexible walls allow them to probe and adhere temporarily to the interior of the cracks. The release of nanoparticles is made possible by the thin microcapsule wall (comparable to the diameter of the nanoparticles) and by the favourable (hydrophobic-hydrophobic) interactions between the nanoparticle and the cracked surface. 相似文献
119.
The quest for alternative energy sources has stimulated interest in several new materials. Using an aqueous suspension of zinc oxide nanoparticles in specially-designed electrochemical cells we have observed significant voltage (maximum 498.0 mV) and storage capacity (∼60 h) upon thermal excitation. Voltage increased gradually with increasing temperature. The cells exhibited reasonable energy conversion efficiency (maximum 1.05%). Moreover, increases in efficiency and storage duration were observed with the insertion of a planar lipid membrane (PLM) within the electrochemical cell, since the hydrophobic barrier of the lipid membrane hindered back recombination of the charges produced by thermal excitation. The novelty of the cells lies in the fact that voltage was generated by utilizing the heat energy of solar radiation, as opposed to the light quanta of the solar influx used in conventional photovoltaic cells. 相似文献
120.
Impact of reform and privatization on consumers: A case study of power sector reform in Orissa,India
Orissa is the first state in India to have undergone reform in the power sector, with the government withdrawing its control. The model of this reform is known as the WB–Orissa model. The goal of this paper is to examine the impact of this reform on consumers of electricity, which has been measured using multiple regression models. The variables represent the parameters that consumers are most interested in, and the regression coefficients represent the weights of the corresponding variables. The data were collected using a survey methodology. The impact of reform was found to be mixed. Some groups of consumers saw benefits, while others felt a negative impact. A focus group study was conducted to identify the variables of interest to consumers of electricity. The model was used to estimate consumer benefit and was validated using primary data and structural equation modeling. The study revealed beneficial aspects of reform and areas with no benefits. 相似文献