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41.
Marina Enterría Fabián Suárez-García Amelia Martínez-Alonso Juan M.D. Tascón 《Carbon》2012,50(10):3826-3835
Hierarchical micro–mesoporous carbons with high porosity development and ordered structure were prepared. The innovative proposal consists in developing microporosity in ordered mesoporous carbon by chemical activation in template presence in order to minimize the structural damage. Thus, we have directly carried out the chemical activation of a mesoporous carbon/silica composite with KOH. The effect on mesoporous ordered structure of both KOH/carbon ratio and activation temperature has been studied. Following chemical activation the specific surface area is increased from 341 to 1757 m2/g and the micropore volume becomes almost six times larger than initial value. Although a slight widening of the mesopore distribution and an increase in the mesopore volume has been observed during activation, TEM and XRD results reveal an excellent conservation of the ordered mesoporous structure during activation even at conditions well above the limits that a CMK-3 type carbon can resist. 相似文献
42.
Ajna Tóth Kateryna V. Voitko Olga Bakalinska Gennadiy P. Prykhod’ko Imre Bertóti Amelia Martínez-Alonso Juan M.D. Tascón Vladimir M. Gun’ko Krisztina László 《Carbon》2012,50(2):577-585
The poor compatibility of carbon materials with different dispersion media can be overcome by surface functionalization. In this work, multiwall carbon nanotubes (MWCNTs) were doped by oxygen and nitrogen at low concentrations. Morphological and structural changes caused by chemical treatment were monitored using nitrogen, propane and water vapor adsorption measurements. Pore size distribution (PSD) functions derived from various models are compared. The contribution of slit-shaped pores to the total surface area available for adsorbed molecules is smaller than that of cylindrical pores. Functionalities with heteroatoms (both O and N) enhance water adsorption onto MWCNTs. However, no statistical difference is observed between the water adsorption properties of O- or N-containing MWCNTs. 相似文献
43.
Amelia Barreiro Riccardo Rurali Eduardo R. Hernández Adrian Bachtold 《Small (Weinheim an der Bergstrasse, Germany)》2011,7(6):698-698
The reversible atomic‐mass transport along graphene devices has been achieved. The motion of Al and Au in the form of atoms or clusters is driven by applying an electric field between the metal electrodes that contact the graphene sheet. It is shown that Al moves in the direction of the applied electric field whereas Au tends to diffuse in all directions. The control of the motion of Al is further demonstrated by achieving a 90° turn, using a graphene device patterned in a crossroads configuration. The controlled motion of Al is attributed to the charge transfer from Al onto the graphene so that the Al is effectively charged and can be accelerated by the applied electric field. To get further insight into the actuation mechanism, theoretical simulations of individual Al and Au impurities on a perfect graphene sheet were performed. The direct (electrostatic) force was found to be ~1 pN and dominant over the wind force. These findings hold promise for practical use in future mass transport in complex circuits. 相似文献
44.
María Julia Spotti Martina J. Perduca Andrea Piagentini Liliana G. Santiago Amelia C. Rubiolo Carlos R. Carrara 《Food Hydrocolloids》2013
The effect of Maillard reaction on the mechanical properties of whey protein isolate (WPI) heat-induced gels was evaluated. WPI and dextran (15–25 kDa) conjugates were obtained by controlled dry heating during storage at 60 °C and 63% relative humidity for 2, 5 and 9 days. Changes in browning intensity and content of free amino groups were used to estimate the Maillard reaction. A decrease in free amino groups of WPI was observed when increasing polysaccharide concentration and reaction time. An increase in both a* and b* CIE Lab colour parameters indicated the development of a reddish-brown colour, typical of the Maillard reaction. Uniaxial compression and stress relaxation tests were performed to measure the mechanical properties of mixed and conjugate gels. Maillard reaction significantly modified the mechanical properties of WPI/DX gels, and even prevented fracture when conjugate gels were subjected to 80% deformation in uniaxial compression test. 相似文献
45.
Virginia León-Ruiz Soledad Vera Amelia V. González-Porto María Paz San Andrés 《Food Analytical Methods》2013,6(2):488-496
An isocratic RP-HPLC method has been developed for the identification and quantification of water-soluble vitamins in honey. The mobile phase tested was an aqueous solution of sulphuric acid and the detection was carried out simultaneously by UV and fluorescence. The separation of vitamins C (l-ascorbic acid), B1 (thiamine), B3N (nicotinamide), B3H (nicotinic acid), B5 (d-pantothenic acid) and B6 (pyridoxine) is achieved in these conditions in 15 min. The addition to the mobile phase of methanol 2 %?v/v reduced significantly the analysis time in the separation of these vitamins up to 10 min. Moreover, in presence of a cationic surfactant hexadecyltrimethylammonium bromide (CTAB) in the mobile phase, the separation of vitamin C, B1, B3N, B3H, B2 (riboflavin) and B6 is possible in 6 min. The combination of both mobile phases, H2SO4/methanol and H2SO4/methanol/CTAB, has been applied to the analysis, in isocratic mode, of several monofloral honeys (rosemary, thyme, lavender, chestnut, echium) and a honeydew honey in a short time analysis. 相似文献
46.
Nunzia Novizio Raffaella Belvedere Emanuela Pessolano Silvana Morello Alessandra Tosco Pietro Campiglia Amelia Filippelli Antonello Petrella 《International journal of molecular sciences》2021,22(20)
The tumor microenvironment (TME) is a dynamic system where nontumor and cancer cells intercommunicate through soluble factors and extracellular vesicles (EVs). The TME in pancreatic cancer (PC) is critical for its aggressiveness and the annexin A1 (ANXA1) has been identified as one of the oncogenic elements. Previously, we demonstrated that the autocrine/paracrine activities of extracellular ANXA1 depend on its presence in EVs. Here, we show that the complex ANXA1/EVs modulates the macrophage polarization further contributing to cancer progression. The EVs isolated from wild type (WT) and ANXA1 knock-out MIA PaCa-2 cells have been administrated to THP-1 macrophages finding that ANXA1 is crucial for the acquisition of a protumor M2 phenotype. The M2 macrophages activate endothelial cells and fibroblasts to induce angiogenesis and matrix degradation, respectively. We have also found a significantly increased presence of M2 macrophage in mice tumor and liver metastasis sections previously obtained by orthotopic xenografts with WT cells. Taken together, our data interestingly suggest the relevance of ANXA1 as potential diagnostic/prognostic and/or therapeutic PC marker. 相似文献
47.
Isabel de Marco Juan Andres Legarreta M Felisa Laresgoiti Amelia Torres Jose F. Cambra M Jesús Chomn Blanca Caballero Koldo Gondra 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1997,69(2):187-192
An SMC (Sheeting Moulding Compound) of fibre-glass and orthophthalic polyester has been pyrolysed in a 3·5 dm3 autoclave for 30 min in a nitrogen atmosphere at 300, 400, 500, 600 and 700°C. Gas yields of 8–13 weight%, liquid yields of 9–16 weight% and solid residues of 72–82 weight% were obtained. The suitability of the pyrolysis process for recycling SMC is discussed. The characteristics, compositions and possible ways of reusing the liquid and gaseous fractions are presented. The solid pyrolysis residue has been recycled in another thermoset composite (Bulk Moulding Compound, BMC) and its mechanical properties have been compared with those of virgin BMC. The main conclusion is that pyrolysis can be an appropriate method for recycling thermoset polymeric composites such as SMC. The pyrolysis gas fraction can be sufficient to provide the energy requirements of the process plant. The pyrolysis liquids have high gross calorific values (36·8 MJ kg−1) and are non-polluting liquid fuels; about 40 weight% of such liquids could be used as petrols, and the remaining 60% could be mixed with fuel oils. The solid pyrolysis residue can be recycled in BMC with no detrimental effect on the BMC mechanical properties. Concerning temperature, it has been concluded that 400–500°C are the most suitable temperatures for recycling SMC by pyrolysis. © 1997 SCI. 相似文献
48.
Andrew W. Kelly Amelia M. Wheaton Aaron D. Nicholas Howard H. Patterson Robert D. Pike 《Journal of Inorganic and Organometallic Polymers and Materials》2018,28(2):528-534
Catena-poly[fac-triiodobismuth(III)-tris-(µ-ethane-1,2-diylbis(diphenylphosphane oxide-κ2O,O′))], a 2-D sheet network of BiI3 was synthesized from BiI3 and ethane-1,2-diylbis(diphenylphosphane oxide) (DppeO2) in tetrahydrofuran. The crystal structure revealed a trigonal structure with three-fold symmetry at Bi. Bismuth centers show fac-BiI3O3 coordination, with Bi–I?=?2.9416(2) Å and Bi–O?=?2.4583(17) Å. The I–Bi–I and O–Bi–O angles (95.520(7)° and 79.04(6)°, respectively) indicate trigonal distortion in the Bi octahedron. Bridging DppeO2 ligands centered on inversion centers give rise to a 2-D sheet polymer. The 8.3 Å thick sheets consist of three layers in a sandwich structure. The outer layers are composed of phenyl rings and BiI3 groups with the iodide atoms pointing outward. The central layer consists of the O=PCH2CH2P=O bridging groups. Computational results suggest that semi-conducting behavior arises from Bi(III) centers. A halide to DppeO2 π* transition is suggested by theoretical results. 相似文献
49.
Understanding the preferential oxidation of carbon monoxide (PrOx) using size‐controlled Au nanocrystal catalyst 下载免费PDF全文
Arik Beck An‐Chih Yang Amelia R. Leland Andrew R. Riscoe Francisco A. Lopez Emmett D. Goodman Matteo Cargnello 《American Institute of Chemical Engineers》2018,64(8):3159-3167
Removing CO from hydrogen streams is an important industrial process. The catalytic preferential oxidation of CO (PrOx) is a promising method for CO removal, leaving the hydrogen concentration unchanged. Here, the effect of size and support on the gold‐catalyzed PrOx reaction using size‐controlled Au nanocrystals (NCs) is investigated. For all supports, Au NC sizes of 2–5 nm show the highest rates, whereas for larger sizes rates drop. Ceria‐supported Au shows by far the best performance. By analyzing the dependency of the reaction rate on the NC diameter, the most active centers for CO oxidation on Au/CeO2 are Au+ corner atoms at the interface with the support, resulting in 2.1 nm Au NCs supported on ceria reaching full O2 conversion and CO selectivity of about 50%. Therefore, it is suggested that increasing the fraction of Au‐ceria interface sites would lead to the best performing materials for this reaction. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3159–3167, 2018 相似文献
50.
Virtual water is an important addendum to how we view a country's water resources. This study examines the virtual water embedded in Jordan's agricultural produce and its impact on future water–energy–food policies. Blue and green virtual waters are calculated from data on rainfall, crop patterns, yields, and water requirements at the district level. Results highlight the advantages of blue water usage in the Jordan Valley and of harnessing more available green water in the Highlands, with both displaying low energy impact. Results also emphasize the high groundwater usage and energy footprint in the Desert regions, signalling a need to rein in groundwater extraction and take advantage of solar power. 相似文献