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381.
Giuliano M. Laudone G. Peter Matthews Patrick A. C. Gane Alexander G. Matthews Cathy J. Ridgway Joachim Schoelkopf Stephen A. Huggett 《Transport in Porous Media》2007,66(3):403-419
An algorithm has been developed for the calculation of the size of the effective structural or skeletal elements which make
up the solid phase of an unconsolidated or consolidated porous block. It is based on a previously presented algorithm, but
it has now been validated on unconsolidated samples and tested on consolidated samples. It also includes a virtual reality
representation of the structures. First, a network model named Pore-Cor is made to reproduce the percolation behaviour of
the experimental sample, by matching its simulated percolation characteristics to an experimental mercury intrusion curve.
The algorithm then grows skeletal elements between the cubic pores and cylindrical throats of the void network model until
they touch up to four of the adjacent void features. The size distributions of the simulated solid elements are compared with
each other and with experimentally determined particle size distributions, using a Mann–Whitney test. The algorithm was shown
to simulate skeletal elements with the correct trends in size distribution for two different sand samples, provided the sand
packed itself optimally under the applied mercury pressure. It was also applied to two samples of variously compressed calcium
carbonate powder, having fine and coarse particle size distributions respectively. The simulation demonstrated that on compressing
the powder at the minimum force, the skeletal elements differed from the constituent particle sizes, as expected. The average
size of the skeletal elements increased as the compression force was increased on the calcium carbonate powders. The results
suggest that the method could be useful as a tool for probing the effect of compaction on aggregation or sintering, and for
studying other effects such as cementation in geological samples, where other more direct techniques cannot be applied. 相似文献
382.
383.
Raffaello Lazzaroni Roberta Settambolo Giuliano Alagona Caterina Ghio 《Coordination chemistry reviews》2010,254(5-6):696-706
This review describes experimental results obtained for regioselectivities and diastereoselectivities in rhodium-catalyzed hydroformylations and deuterioformylations of a variety of unsaturated substrates with unmodified Rh catalysts and compares them with values computed in the density functional theory (DFT) framework. Deuterioformylation experiments pointed out that under mild reaction conditions isomeric alkyl metal intermediate formation is non-reversible; hence the selectivity for alkyls reflects the selectivity for the aldehydes. The stability of the relevant alkyl rhodium transition states (TS) has been determined with computational methods at the B3P86/6-31G* level (employing effective core potentials for Rh in the LanL2DZ valence basis set). Theoretical results turn out to be in good agreement with the experimental ones obtained under mild reaction conditions. Significant differences between theory and experiment are conversely obtained for hydroformylations of vinylidenic olefins, such as 1,1-diphenylethene, carried out at high temperature, where β-hydride elimination takes place. To clarify the reaction mechanism under those reaction conditions, it was necessary to compute the whole reaction mechanism, including zero point and thermal corrections also. The calculations, performed on the hydroformylation of 1,1-diphenylethene (yielding almost exclusively linear aldehydes), allowed us to put forward a novel explanation for that behavior: the addition of the fourth CO group to the tricarbonyl intermediate to give the tetracarbonyl one is prevented in the branched isomer, but not in the linear isomer. 相似文献
384.
385.
The decay of a steady acoustic field in an enclosure is studied both theoretically and experimentally. Our main result is that the initial part of any local sound decay is driven by an exponential function of time whose rate constant is equal in modulus to the inverse of the mean energy velocity divergence. This is empirically demonstrated by experimental analysis of both 1-D and 3-D case studies, thus showing that the reverberation time is strictly connected with the sound energy velocity field and can be determined from its differential properties. A further property of the mean energy velocity is found: it is related not only with the reverberation time, but also with the angular momentum density and with the non-uniform distribution of energy. 相似文献
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389.
Elisabetta Rubini Marco Minacori Giuliano Paglia Alberto Macone Silvia Chichiarelli Fabio Altieri Margherita Eufemi 《Molecules (Basel, Switzerland)》2021,26(23)
The β-isomer of hexachlorocyclohexane (β-HCH) is a globally widespread pollutant that embodies all the physicochemical characteristics of organochlorine pesticides, constituting an environmental risk factor for a wide range of noncommunicable diseases. Previous in vitro studies from our group disclosed the carcinogenic potential of β-HCH, which contributes to neoplastic transformation by means of multifaceted intracellular mechanisms. Considering the positive evidence regarding the protective role of natural bioactive compounds against pollution-induced toxicity, micronutrients from olive and tomato endowed with the capability of modulating β-HCH cellular targets were tested. For this purpose, the solution obtained from a patented food supplement (No. EP2851080A1), referred to as Tomato and Olive Bioactive Compounds (TOBC), was administered to the androgen-sensitive prostate cancer cells LNCaP and different biochemical and cellular assays were performed to evaluate its efficiency. TOBC shows a dose-dependent significant chemoprotection by contrasting β-HCH-induced intracellular responses such as STAT3 and AhR activation, disruption of AR signaling, antiapoptotic and proliferative activity, and increase in ROS production and DNA damage. These experimental outcomes identified TOBC as a suitable functional food to be included in a diet regimen aimed at defending cells from β-HCH negative effects, recommending the development of tailored enriched formulations for exposed individuals. 相似文献
390.
Annibale Giuliano Marangoni Giampaolo Pitteri Bruno Visentin Fabiano Bobbo Tatiana 《Transition Metal Chemistry》2000,25(4):485-489
The reactions of AuIII, PtII and PdII complexes with 2-pyridinecarboxaldehyde (2CHO-py) have been examined in protic (H2O, MeOH, EtOH) and aprotic (DMF, CH2Cl2) solvents. Compounds in which the pyridine ligand is N-coordinated, either in the original aldehydic form or in a new form
derived from addition of one or two protic molecules, have been isolated, namely: [Au(2CHO-py · H2O)Cl3], [Au(2CHO-py · MeOH)Cl3], [Au(2CHO-py · 2EtOH)Cl3], cis-[Pt(2CHO-py)2Cl2], trans-[Pd(2CHO-py)2Cl2], trans-[Pt(dmso)(2CHO-py)Cl2], [Pt{C5H4N-(CH2SMe)}Cl(2CHO-py)](ClO4), [Pt(terpy)(2CHOpy)](ClO4)2, [Pt(terpy)(2CHO-py · H2O)](ClO4)2 (terpy = 2,2′:6′,2′′-terpyridine). 1H-n.m.r. experiments show that the addition of the protic molecule(s) to the PtII and PdII complexes is reversible. The effects of the nature of the metal ion and the ancillary ligands as well as of the total charge
of the complexes on the relative stability of the addition products are discussed.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献