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61.
Tobias Schröder Satya Narayan Sahu Dario Anselmetti Jochen Mattay 《Israel journal of chemistry》2011,51(7):725-742
Self-assembly by H-bonding and by metal-coordination of functionalized calix[4]arenes and cavitands to large supramolecular capsules is described. In addition, a new method of analyzing supramolecular recognition processes at the single molecule level is discussed. By measuring interaction forces in a hydrogen-bonded assembly using single-molecule force spectroscopy (SMFS), the dynamics of the self-assembly process can be evaluated. In the future, consequent application of this new technique will influence supramolecular design principles and the use of non-covalent interactions as construction elements in the field of nanotechnology. 相似文献
62.
63.
Roberto C. Dante Pablo Martín-Ramos Pedro Chamorro-Posada Dario Rutto José Vázquez-Cabo Denisse G. Dante 《Fullerenes, Nanotubes and Carbon Nanostructures》2020,28(7):533-540
AbstractIn this work, a new g-C3N4-based Z-scheme with γ-Fe2O3 and β-Ag2Se both n-type semiconductors, and graphite to favor electron exchange is presented. The composite material was studied by XRD, FTIR, UV-Vis, TEM, XPS, TGA, DSC and TOF-SIMS, and the ability of this photocatalytic system to act as a photo-reductant was assessed using crystal violet (CV+) dye. Solar light driven photo-reduction of CV+ in the presence of tri-sodium citrate evidenced a synergistic enhancement of the activity of the composite toward reduction, with ~20 times higher conversion rates per unit of surface area than those of g-C3N4. Photo-oxidation experiments under Xe lamp irradiation in the presence of H2O2 also showed that the AgFeCN composite featured a higher activity (~8×) than g-C3N4. This Z-scheme may deserve further study as a photo-reductant to obtain hydrogen or hydrogenated compounds. Moreover, the use of CV+ may represent a facile procedure that can aid in the selection of new photocatalysts to be used in hydrogen production. 相似文献
64.
A new route for obtaining 1,4-cyclooctadiene by catalytic isomerization of 1,5-cyclooctadiene at low temperature in presence of H2 in a three-phase reactor is presented. Wei, Prater and Silvestri methods are used for the kinetic studies. A comparison of the activity-selectivity patterns of the Pd/pumice catalysts with Pd on silica and Pt and Pd–Pt on pumice catalysts is performed. Although Pt catalysts are not active in the hydro-isomerization of 1,5-cyclooctadiene, the presence of small amount of Pt in Pd/pumice catalysts increases the yield to 1,4-cyclooctadiene. Besides the catalyst characteristics, temperature and H2 pressure influence the production of 1,4-cyclooctadiene. A mechanism of the process is proposed. This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
65.
Marco Domenichini Ranjana Sahai Piero Castrataro Roberto Valsecchi Claudio Tonelli Francesco Greco Paolo Dario 《Microfluidics and nanofluidics》2013,15(6):753-762
The development of multilayer soft lithography methodology has seen polydimethysiloxane (PDMS) as the preferred material for the fabrication of microfluidic devices. However, the functionality of these PDMS microfluidic chips is often limited by the poor chemical resistance of PDMS to certain solvents. Here, we propose the use of a photocurable perfluoropolyether (PFPE), specifically FOMBLIN® MD40 PFPE, as a candidate material to provide a solvent-resistant buffer layer to make the device substantially impervious to chemically induced swelling. We first carried out a systematic study of the solvent resistance properties of FOMBLIN® MD40 PFPE as compared with PDMS. The comparison presented here demonstrates the superiority of FOMBLIN® MD40 PFPE over PDMS in this regard; moreover, the results permitted to categorize solvents in four different groups depending on their swelling ratio. We then present a step-by-step recipe for a novel fabrication process that uses multilayer lithography to construct a comprehensive solvent-resistant device with fluid and control channels integrated with a valve structure and also permitting easy establishment of outside connections. 相似文献
66.
Heinis Christian; Huber Adrian; Demartis Salvatore; Bertschinger Julian; Melkko Samu; Lozzi Luisa; Neri Paolo; Neri Dario 《Protein engineering, design & selection : PEDS》2001,14(12):1043-1052
Phage display has been shown to facilitate greatly the selectionof polypeptides with desired properties by establishing a directlink between the polypeptide and the gene that encodes it. However,selection for catalytic activities displayed on phage remainsa challenge, since reaction products diffuse away from the enzymeand make it difficult to recover catalytically active phageenzymes.We have recently described a selection methodology in whichthe reaction substrate (and eventually the reaction product)is anchored on calmodulin-tagged phageenzymes by meansof a calmodulin binding peptide. Phage displaying a catalyticactivity are physically isolated by means of affinity reagentsspecific for the product of reaction. In this study, we investigatedthe efficiency of selection for catalysis by phage display,using a ligase (the Escherichia coli biotin ligase BirA) andan endopeptidase (the rat trypsin His57 相似文献
68.
At EuroCrypt '99 Paillier proposed a new encryption scheme based on higher residuosity classes. The new scheme was proven
to be one-way under the assumption that computing
N -residuosity classes in Z
N2
*
is hard. Similarly the scheme can be proven to be semantically secure under a much stronger decisional assumption: given w ∈ Z
N2
*
it is impossible to decide if w is an N -residue or not.
In this paper we examine the bit security of Paillier's scheme. We prove that if computing residuosity classes is hard, then
given a random w it is impossible to predict the least significant bit of its class significantly better than at random. This immediately
yields a way to obtain semantic security without relying on the decisional assumption (at the cost of several invocations
of Paillier's original function).
In order to improve efficiency we then turn to the problem of simultaneous security of many bits. We prove that Paillier's
scheme hides n-b (up to O(n) ) bits if one assumes that computing the class c of a random w remains hard even when we are told that c<2
b
. We thoroughly examine the security of this stronger version of the intractability of the class problem.
An important theoretical implication of our result is the construction of the first trapdoor function that hides super-logarithmically
(up to O(n) ) many bits. We generalize our techniques to provide sufficient conditions for a trapdoor function to have this property. 相似文献
69.
The 228Th/228Ra activity ratio can provide a tool for age measurements of newly formed minerals, down to about 15 yr. A general discussion of the method is followed by an experimental check on an aphthitalite brine, crystallized from a geothermal well at Cesano (Rome) in July, 1978 (the real age is 85 ± 5 months). It yielded an age of 75 + 8/-5 months through alpha-spectrometry activity measurements, and 85 ± 3 months through gamma-spectrometry activity measurements. A residence time of the fluid in the rock ranging from 3 to 10 centuries has been estimated by comparing the Ra isotopic composition of the fluid with the U/Th ratio of the wall rocks, according to a model proposed by Cherdyntsev (1971). 相似文献
70.
Graves Franklynn C.; Wallen Kim; Maestripieri Dario 《Canadian Metallurgical Quarterly》2002,116(3):489
This study investigated the role of the endogenous opioid system in maternal and affiliative behavior of group-living rhesus macaque (Macaca mularta) mothers with a history of abusive parenting. 18 mothers received an injection of the opioid antagonist naltrexone or saline for 5 days per wk for the first 4 wks of the infant's life. After treatment, mother-infant pairs were focally observed. Naltrexone did not significantly affect infant abuse or other measures of maternal behavior. Naltrexone increased the amount of grooming received by mothers from other group members and reduced the mothers' rate of displacement activities such as scratching, yawning, and self-grooming. These results concur with previous primate studies in suggesting that opioids mediate the rewarding effects of receiving grooming and affect anxiety-related behaviors. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献