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Andreazza P, Lemoine A, Coati A, Nelli D, Ferrando R, Garreau Y, Creuze J, Andreazza-Vignolle C. From metastability to equilibrium during the sequential growth of Co-Ag supported clusters: a real-time investigation. Nanoscale 2021; 13:6096-6104. [PMID: 33683240 DOI: 10.1039/d0nr08862e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Atomic motions and morphological evolution of growing Co-Ag nanoparticles are followed in situ and in real time, by wide and small angle X-ray scattering obtained simultaneously in grazing incidence geometry (GISAXS and GIWAXS), in single or multi-wavelength anomalous modes. The structural analysis of the experimental data is performed with the aid of equilibrium Monte Carlo simulations and of molecular-dynamics simulations of nanoparticle growth. Growth is performed by depositing Co atoms above preformed Ag nanoparticles. This growth procedure is strongly out of equilibrium, because Ag tends to surface segregation, and generates complex growth sequences. The real time analysis of the growth allows to follow the nanoparticle evolution pathways almost atom-by-atom, determining the key mechanisms during Co deposition: starting with the incorporation of Co atoms in sub-surface positions, to the off-center Co domain formation, then by which the nanoparticles finally approach their equilibrium quasi-Janus then core-shell structures.
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Affiliation(s)
- P Andreazza
- Interfaces, Confinement, Matériaux et Nanostructures, ICMN, Université d'Orléans, CNRS, Orléans, France.
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Grubinska B, Chen L, Alsaloum M, Rampal N, Matson DJ, Yang C, Taborn K, Zhang M, Youngblood B, Liu D, Galbreath E, Allred S, Lepherd M, Ferrando R, Kornecook TJ, Lehto SG, Waxman SG, Moyer BD, Dib-Hajj S, Gingras J. Rat Na V1.7 loss-of-function genetic model: Deficient nociceptive and neuropathic pain behavior with retained olfactory function and intra-epidermal nerve fibers. Mol Pain 2020; 15:1744806919881846. [PMID: 31550995 PMCID: PMC6831982 DOI: 10.1177/1744806919881846] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Recapitulating human disease pathophysiology using genetic animal models is a
powerful approach to enable mechanistic understanding of genotype–phenotype
relationships for drug development. NaV1.7 is a sodium channel
expressed in the peripheral nervous system with strong human genetic validation
as a pain target. Efforts to identify novel analgesics that are nonaddictive
resulted in industry exploration of a class of sulfonamide compounds that bind
to the fourth voltage-sensor domain of NaV1.7. Due to sequence
differences in this region, sulfonamide blockers generally are potent on human
but not rat NaV1.7 channels. To test sulfonamide-based chemical
matter in rat models of pain, we generated a humanized NaV1.7 rat
expressing a chimeric NaV1.7 protein containing the
sulfonamide-binding site of the human gene sequence as a replacement for the
equivalent rat sequence. Unexpectedly, upon transcription, the human insert was
spliced out, resulting in a premature stop codon. Using a validated antibody,
NaV1.7 protein was confirmed to be lost in the brainstem, dorsal
root ganglia, sciatic nerve, and gastrointestinal tissue but not in nasal
turbinates or olfactory bulb in rats homozygous for the knock-in allele
(HOM-KI). HOM-KI rats exhibited normal intraepidermal nerve fiber density with
reduced tetrodotoxin-sensitive current density and action potential firing in
small diameter dorsal root ganglia neurons. HOM-KI rats did not exhibit
nociceptive pain responses in hot plate or capsaicin-induced flinching assays
and did not exhibit neuropathic pain responses following spinal nerve ligation.
Consistent with expression of chimeric NaV1.7 in olfactory tissue,
HOM-KI rats retained olfactory function. This new genetic model highlights the
necessity of NaV1.7 for pain behavior in rats and indicates that
sufficient inhibition of NaV1.7 in humans may reduce pain in
neuropathic conditions. Due to preserved olfactory function, this rat model
represents an alternative to global NaV1.7 knockout mice that require
time-intensive hand feeding during early postnatal development.
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Affiliation(s)
- B Grubinska
- Neuroscience Department, Amgen Research, Cambridge, MA, USA.,Voyager Therapeutics, Cambridge, MA, USA
| | - L Chen
- Department of Neurology, Yale University, New Haven, CT, USA.,Center for Neuroscience & Regeneration Research, Yale University, West Haven, CT, USA.,Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT, USA
| | - M Alsaloum
- Department of Neurology, Yale University, New Haven, CT, USA.,Center for Neuroscience & Regeneration Research, Yale University, West Haven, CT, USA.,Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT, USA.,Interdepartmental Neuroscience Program, Yale University School of Medicine, New Haven, CT, USA.,Yale Medical Scientist Training Program, Yale School of Medicine, New Haven, CT, USA
| | - N Rampal
- Neuroscience Department, Amgen Research, Thousand Oaks, CA, USA
| | - D J Matson
- Neuroscience Department, Amgen Research, Cambridge, MA, USA
| | - C Yang
- Neuroscience Department, Amgen Research, Cambridge, MA, USA
| | - K Taborn
- Neuroscience Department, Amgen Research, Cambridge, MA, USA.,Wave Life Sciences, Ltd, Cambridge, MA, USA
| | - M Zhang
- Neuroscience Department, Amgen Research, Thousand Oaks, CA, USA
| | - B Youngblood
- Neuroscience Department, Amgen Research, Thousand Oaks, CA, USA
| | - D Liu
- Neuroscience Department, Amgen Research, Thousand Oaks, CA, USA
| | - E Galbreath
- Comparative Biology and Safety Sciences, Amgen Research, Cambridge, MA, USA.,Takeda Pharmaceutical Company Ltd, Cambridge, MA, USA
| | - S Allred
- Comparative Biology and Safety Sciences, Amgen Research, South San Francisco, CA, USA.,Seattle Genetics, Bothell, WA, USA
| | - M Lepherd
- Comparative Biology and Safety Sciences, Amgen Research, South San Francisco, CA, USA.,Genentech, Inc. South San Francisco, CA, USA
| | - R Ferrando
- Comparative Biology and Safety Sciences, Amgen Research, South San Francisco, CA, USA.,AbbVie Stemcentrx, Inc., South San Francisco, CA, USA
| | - T J Kornecook
- Neuroscience Department, Amgen Research, Thousand Oaks, CA, USA.,Biogen Inc., Cambridge, MA, USA
| | - S G Lehto
- Neuroscience Department, Amgen Research, Thousand Oaks, CA, USA
| | - S G Waxman
- Department of Neurology, Yale University, New Haven, CT, USA.,Center for Neuroscience & Regeneration Research, Yale University, West Haven, CT, USA.,Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT, USA
| | - B D Moyer
- Neuroscience Department, Amgen Research, Thousand Oaks, CA, USA
| | - S Dib-Hajj
- Department of Neurology, Yale University, New Haven, CT, USA.,Center for Neuroscience & Regeneration Research, Yale University, West Haven, CT, USA.,Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT, USA
| | - J Gingras
- Neuroscience Department, Amgen Research, Cambridge, MA, USA.,Homology Medicine Inc., Bedford, MA, USA
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3
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Smerieri M, Pal J, Savio L, Vattuone L, Ferrando R, Tosoni S, Giordano L, Pacchioni G, Rocca M. Spontaneous Oxidation of Ni Nanoclusters on MgO Monolayers Induced by Segregation of Interfacial Oxygen. J Phys Chem Lett 2015; 6:3104-3109. [PMID: 26267209 DOI: 10.1021/acs.jpclett.5b01362] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report the study of Ni nanoclusters deposited on MgO/Ag(100) ultrathin films (one monolayer) at T = 200 K. We show by STM analysis and DFT calculations that in the limit of low Ni coverage the formation of nanoclusters of four to six atoms occurs and that these aggregates are flat rather than 3D, as expected for Ni tetramers, pentamers, or hexamers. Both the shape of the clusters and the interatomic distance between neighboring Ni atoms are indicative that the nanoparticles do not consist of pure metal atoms but that a NiyOx structure has formed thanks to the availability of atomic oxygen accumulated at the MgO/Ag interface, with Ni clusters acting as oxygen pumps. Besides being of relevance in view of the use of metal nanoclusters in catalysis and other applications, this finding gives a further proof of the peculiar behavior of ultrathin oxide films.
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Affiliation(s)
- M Smerieri
- †IMEM-CNR, U.O.S. Genova, Via Dodecaneso 33, 16146 Genova, Italy
| | - J Pal
- †IMEM-CNR, U.O.S. Genova, Via Dodecaneso 33, 16146 Genova, Italy
- ‡Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, 16146 Genova, Italy
| | - L Savio
- †IMEM-CNR, U.O.S. Genova, Via Dodecaneso 33, 16146 Genova, Italy
| | - L Vattuone
- †IMEM-CNR, U.O.S. Genova, Via Dodecaneso 33, 16146 Genova, Italy
- ‡Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, 16146 Genova, Italy
| | - R Ferrando
- †IMEM-CNR, U.O.S. Genova, Via Dodecaneso 33, 16146 Genova, Italy
- §Dipartimento di Chimica e Chimica Industriale, Università di Genova, Via Dodecaneso 31, 16146 Genova, Italy
| | - S Tosoni
- ∥Dipartimento di Scienza dei Materiali, Università Milano Bicocca, via R. Cozzi 55, 20125 Milano, Italy
| | - L Giordano
- ∥Dipartimento di Scienza dei Materiali, Università Milano Bicocca, via R. Cozzi 55, 20125 Milano, Italy
| | - G Pacchioni
- ∥Dipartimento di Scienza dei Materiali, Università Milano Bicocca, via R. Cozzi 55, 20125 Milano, Italy
| | - M Rocca
- †IMEM-CNR, U.O.S. Genova, Via Dodecaneso 33, 16146 Genova, Italy
- ‡Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, 16146 Genova, Italy
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Ferrando R. The water problem. World Rev Nutr Diet 2015; 11:17-45. [PMID: 5366455 DOI: 10.1159/000387574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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7
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Laganapan AMK, Videcoq A, Bienia M, Ala-Nissila T, Bochicchio D, Ferrando R. Computation of shear viscosity of colloidal suspensions by SRD-MD. J Chem Phys 2015; 142:144101. [PMID: 25877556 DOI: 10.1063/1.4917039] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The behaviour of sheared colloidal suspensions with full hydrodynamic interactions (HIs) is numerically studied. To this end, we use the hybrid stochastic rotation dynamics-molecular dynamics (SRD-MD) method. The shear viscosity of colloidal suspensions is computed for different volume fractions, both for dilute and concentrated cases. We verify that HIs help in the collisions and the streaming of colloidal particles, thereby increasing the overall shear viscosity of the suspension. Our results show a good agreement with known experimental, theoretical, and numerical studies. This work demonstrates the ability of SRD-MD to successfully simulate transport coefficients that require correct modelling of HIs.
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Affiliation(s)
- A M K Laganapan
- SPCTS, UMR 7315, ENSCI, CNRS, Centre Européen de la Céramique, 12 rue Atlantis, 87068 Limoges Cedex, France
| | - A Videcoq
- SPCTS, UMR 7315, ENSCI, CNRS, Centre Européen de la Céramique, 12 rue Atlantis, 87068 Limoges Cedex, France
| | - M Bienia
- SPCTS, UMR 7315, ENSCI, CNRS, Centre Européen de la Céramique, 12 rue Atlantis, 87068 Limoges Cedex, France
| | - T Ala-Nissila
- COMP CoE at the Department of Applied Physics, Aalto University School of Science, P.O. Box 11000, FIN-00076 Aalto, Espoo, Finland
| | - D Bochicchio
- Dipartimento di Fisica and CNR-IMEM, via Dodecaneso 33, Genova I-16146, Italy
| | - R Ferrando
- Dipartimento di Fisica and CNR-IMEM, via Dodecaneso 33, Genova I-16146, Italy
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8
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Diamant M, Rahav S, Ferrando R, Alexandrowicz G. Interpretation of surface diffusion data with Langevin simulations: a quantitative assessment. J Phys Condens Matter 2015; 27:125008. [PMID: 25743627 DOI: 10.1088/0953-8984/27/12/125008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Diffusion studies of adsorbates moving on a surface are often analyzed using 2D Langevin simulations. These simulations are computationally cheap and offer valuable insight into the dynamics, however, they simplify the complex interactions between the substrate and adsorbate atoms, neglecting correlations in the motion of the two species. The effect of this simplification on the accuracy of observables extracted using Langevin simulations was previously unquantified. Here we report a numerical study aimed at assessing the validity of this approach. We compared experimentally accessible observables which were calculated using a Langevin simulation with those obtained from explicit molecular dynamics simulations. Our results show that within the range of parameters we explored Langevin simulations provide a good alternative for calculating the diffusion procress, i.e. the effect of correlations is too small to be observed within the numerical accuracy of this study and most likely would not have a significant effect on the interpretation of experimental data. Our comparison of the two numerical approaches also demonstrates the effect temperature dependent friction has on the calculated observables, illustrating the importance of accounting for such a temperature dependence when interpreting experimental data.
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Affiliation(s)
- M Diamant
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 32000, Israel
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9
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Abstract
The possible mechanisms for the B1 (NaCl-type) to B2 (CsCl-type) transition in crystalline colloidal clusters of equally sized particles are studied by means of two computational techniques: metadynamics and nudged elastic band calculations. The system is modelled by a screened Coulomb potential. Different interaction ranges are considered. The transition from a perfect NaCl cubic cluster to a full CsCl cluster is forced by metadynamics, revealing a transition path with intermediate metastable configurations in which planes are shifted one by one. The presence of metastable configurations in the transition path, corresponding to a certain number of NaCl planes turned into CsCl, has clear analogies with the known Hyde and O'Keeffe mechanism for ionic crystals, with some important differences due to finite-size effects. These comprise the fact that the transition starts by shifting a surface plane by means of a row-by-row mechanism that has no analog in bulk crystals. The energy barriers between the local minima in the transition path are calculated, showing that the barriers strongly depend on the screening length, in such a way that the B1 metastable phase can have very long lifetimes when the interaction is sufficiently long-ranged.
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Affiliation(s)
- D Bochicchio
- Dipartimento di Fisica and CNR-IMEM, Via Dodecaneso 33, Genova I-16146, Italy
| | - A Videcoq
- SPCTS, UMR 7315, ENSCI, CNRS, Centre Europeéen de la Céramique, 12 rue Atlantis, 87068 Limoges cedex, France
| | - R Ferrando
- Dipartimento di Fisica and CNR-IMEM, Via Dodecaneso 33, Genova I-16146, Italy
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10
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Abstract
Atomic-scale imaging using aberration-corrected scanning transmission electron microscopy reveals direct evidence for semicoherent interfacial epitaxy and coordinate-dependent surface contraction for the fcc (001) oriented Au nanoparticles (2-3 nm in diameter), suggesting that their interaction with the substrate is weaker than previously assumed. A significant change in interfacial separation distance from 2.47 ± 0.12 Å for the fcc (001) oriented Au nanoparticles to 3.07 ± 0.11 Å for the fcc (111) oriented Au nanoparticles has also been observed. These results are used to verify the atomistic models generated by the global optimization calculations, which shed further light on the intricate relation between the interfacial energy and the atomic structure of the nanoparticle and their combined effect on the inhomogeneous surface structural relaxation of supported nanoparticles.
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Affiliation(s)
- Y Han
- †Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - R Ferrando
- ‡Dipartimento di Fisica, Università di Genova and CNR/IMEM, via Dodecaneso 33, 16146 Genova, Italy
| | - Z Y Li
- †Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, United Kingdom
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Tomilov A, Videcoq A, Cerbelaud M, Piechowiak MA, Chartier T, Ala-Nissila T, Bochicchio D, Ferrando R. Aggregation in Colloidal Suspensions: Evaluation of the Role of Hydrodynamic Interactions by Means of Numerical Simulations. J Phys Chem B 2013; 117:14509-17. [DOI: 10.1021/jp407247y] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- A. Tomilov
- SPCTS, UMR 7315,
ENSCI, CNRS; Centre Européen de la Céramique, 12 rue Atlantis, 87068 Limoges cedex, France
| | - A. Videcoq
- SPCTS, UMR 7315,
ENSCI, CNRS; Centre Européen de la Céramique, 12 rue Atlantis, 87068 Limoges cedex, France
| | - M. Cerbelaud
- Institut
des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS, 2 rue de la Houssinière, BP32229, 44322 Nantes cedex 3, France
| | - M. A. Piechowiak
- SPCTS, UMR 7315,
ENSCI, CNRS; Centre Européen de la Céramique, 12 rue Atlantis, 87068 Limoges cedex, France
| | - T. Chartier
- SPCTS, UMR 7315,
ENSCI, CNRS; Centre Européen de la Céramique, 12 rue Atlantis, 87068 Limoges cedex, France
| | - T. Ala-Nissila
- Department
of Applied Physics and COMP CoE, Aalto University School of Science, P.O. Box 11000, FI-00076 Aalto, Espoo, Finland
- Department
of Physics, Brown University, Providence, Rhode Island 02912-8143, United States
| | - D. Bochicchio
- Dipartimento
di
Fisica and CNR-IMEM, Via Dodecaneso
33, Genova I-16146, Italy
| | - R. Ferrando
- Dipartimento
di
Fisica and CNR-IMEM, Via Dodecaneso
33, Genova I-16146, Italy
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Bochicchio D, Videcoq A, Ferrando R. Kinetically driven ordered phase formation in binary colloidal crystals. Phys Rev E Stat Nonlin Soft Matter Phys 2013; 87:022304. [PMID: 23496513 DOI: 10.1103/physreve.87.022304] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 01/17/2013] [Indexed: 06/01/2023]
Abstract
The aggregation of binary colloids of the same size and balanced charges is studied by Brownian dynamics simulations for dilute suspensions. It is shown that, under appropriate conditions, the formation of colloidal crystals is dominated by kinetic effects leading to the growth of well-ordered crystallites of the sodium-chloride (NaCl) bulk phase. These crystallites form with very high probability even when the cesium-chloride (CsCl) phase is more stable thermodynamically. Global optimization searches show that this result is not related to the most favorable structures of small clusters, which are either amorphous or of the CsCl structure. The formation of the NaCl phase is related to the specific kinetics of the crystallization process, which takes place by a two-step mechanism. In this mechanism, dense fluid aggregates form at first and then crystallization follows. It is shown that the type of short-range order in these dense fluid aggregates determines which phase is finally formed in the crystallites. The role of hydrodynamic effects in the aggregation process is analyzed by stochastic rotation dynamics - molecular dynamics simulations, and we find that these effects do not play a major role in the formation of the crystallites.
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Affiliation(s)
- D Bochicchio
- Dipartimento di Fisica and CNR-IMEM, Via Dodecaneso 33, Genova I-16146, Italy
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Piechowiak MA, Videcoq A, Ferrando R, Bochicchio D, Pagnoux C, Rossignol F. Aggregation kinetics and gel formation in modestly concentrated suspensions of oppositely charged model ceramic colloids: a numerical study. Phys Chem Chem Phys 2012; 14:1431-9. [DOI: 10.1039/c1cp22980j] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Piechowiak MA, Videcoq A, Rossignol F, Pagnoux C, Carrion C, Cerbelaud M, Ferrando R. Oppositely charged model ceramic colloids: numerical predictions and experimental observations by confocal laser scanning microscopy. Langmuir 2010; 26:12540-7. [PMID: 20604541 DOI: 10.1021/la101027d] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Fluorescent silica and alumina-like spherical particles with almost equal sizes are synthesized. Dilute aqueous suspensions are prepared with various ratios of those colloidal particles that exhibit opposite surface charges. These suspensions undergo heteroaggregation for a wide range of compositions. The structure of the formed aggregates is analyzed by means of confocal microscopy. The experimental results are compared to those of Brownian dynamics simulations in which the interactions between colloids are modeled by the DLVO potential. Good agreement between experiments and simulations is obtained.
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Affiliation(s)
- M A Piechowiak
- SPCTS, UMR 6638, ENSCI, CNRS, Centre Européen de la Céramique, 12 rue Atlantis, 87068 Limoges Cedex, France
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Cerbelaud M, Ferrando R, Videcoq A. Simulations of heteroaggregation in a suspension of alumina and silica particles: Effect of dilution. J Chem Phys 2010; 132:084701. [DOI: 10.1063/1.3328876] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Kapitán M, Ferrando R, Diéguez E, de Medina O, Aljanati R, Ventura R, Amorin I, Salinas D, Langhain M, Gioia A, Cardoso A, Lago G, Buzó R. Cambios de la perfusión cerebral en la enfermedad de Parkinson: relación con la duración de los síntomas. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/s0212-6982(09)71353-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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18
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Valenti S, Pastorello A, Cappellaro E, Benetti S, Mazzali PA, Manteca J, Taubenberger S, Elias-Rosa N, Ferrando R, Harutyunyan A, Hentunen VP, Nissinen M, Pian E, Turatto M, Zampieri L, Smartt SJ. A low-energy core-collapse supernova without a hydrogen envelope. Nature 2009; 459:674-7. [PMID: 19494909 DOI: 10.1038/nature08023] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Accepted: 03/24/2009] [Indexed: 11/09/2022]
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Abstract
It is shown, by density-functional theory calculations, that gold clusters on the MgO(001) surface prefer cage structures in the size range between 23 and 42 atoms. These structures belong to a new structural family, the open pyramidal hollow cages, which has no counterpart in gas-phase clusters. These cages are possible because of the peculiar features of the Au-Au and Au-MgO interactions, which include strong many-body and directional effects. These effects reinforce the tendency of Au to produce cage structures with respect to the gas phase.
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Affiliation(s)
- R Ferrando
- Dipartimento di Fisica and CNISM, Via Dodecaneso 33, Genova, I16146, Italy
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Kapitán M, Ferrando R, Diéguez E, de Medina O, Aljanati R, Ventura R, Amorin I, Salinas D, Langhain M, Gioia A, Cardoso A, Lago G, Buzó R. [Regional cerebral blood flow changes in Parkinson's disease: correlation with disease duration]. Rev Esp Med Nucl 2009; 28:114-120. [PMID: 19558951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
INTRODUCTION Changes in regional cerebral blood flow (rCBF) have been reported in idiopathic Parkinson's disease (PD). Nonetheless, their typical pattern still remains controversial regarding some features, such as basal ganglia involvement and the main cortical regions affected. Functional neuroimaging makes it possible to identify the brain dysfunctions of the neural circuits underlying the disease. Voxel-based analysis methods make it possible to increase the reliability of the results. OBJECTIVE To assess the rCBF changes in patients with PD and their relation with disease duration. MATERIALS AND METHODS Thirty PD adult patients without dementia underwent evaluation with (99m)Tc-ECD SPECT. SPM5 was used for statistical comparison with 25 normal controls of similar ages. The disease course duration in years was added as a covariate. Additionally, patients with a 6-year evolution or less and those with more than 6 years were compared separately with normal controls. RESULTS Significant hypoperfusion was detected in bilateral premotor and posterior parietal cortex and increase of perfusion was present in the cerebellum. These changes correlated with the years of evolution of the illness. Patients with longer evolution also presented thalamic, subthalamic and basal ganglia hypoperfusion. CONCLUSIONS We describe rCBF changes in PD in neural circuits related with control of movements. These changes are more manifest in patients with a longer duration of the disease.
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Affiliation(s)
- M Kapitán
- Centro de Medicina Nuclear, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
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Ferrando R. Afiatoxin and Oral Contraceptives. Nutr Rev 2009. [DOI: 10.1111/j.1753-4887.1977.tb06589.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Rossi G, Schiappelli G, Ferrando R. Formation Pathways and Energetic Stability of Icosahedral Ag shellCo core Nanoclusters. ACTA ACUST UNITED AC 2009. [DOI: 10.1166/jctn.2009.1116] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Rossi G, Ferrando R. Searching for low-energy structures of nanoparticles: a comparison of different methods and algorithms. J Phys Condens Matter 2009; 21:084208. [PMID: 21817360 DOI: 10.1088/0953-8984/21/8/084208] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Nanoparticles can have unusual, low symmetry or non-crystalline shapes. Since structure determines nanoparticle physical and chemical properties, many efforts have been devoted to predict what are the most stable structural motifs depending on cluster size and composition. The global optimization of the 3N-dimensional potential energy surface of a nanocluster is nevertheless a very difficult computational problem. Here we depict the scenery of the global optimization strategies applied to the study of nanoclusters, focusing on genetic and Basin-hopping approaches. Moreover, several strategies to improve Basin-hopping efficiency are discussed and compared through the optimization of test-systems with different size and composition.
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Affiliation(s)
- G Rossi
- Dipartimento di Fisica, Università di Genova and CNR/INFM, Via Dodecaneso, 33, 16146 Genova, Italy
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24
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Cerbelaud M, Videcoq A, Abélard P, Pagnoux C, Rossignol F, Ferrando R. Heteroaggregation between Al2O3 submicrometer particles and SiO2 nanoparticles: experiment and simulation. Langmuir 2008; 24:3001-3008. [PMID: 18312002 DOI: 10.1021/la702104u] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The aggregation process of a two-component dilute system (3 vol %), made of alumina submicrometer particles and silica nanoparticles, is studied by Brownian dynamics simulations. Alumina and silica particles have very different sizes (diameters of 400 and 25 nm, respectively). The particle-particle interaction potential is of the DLVO form. The parameters of the potential are extracted from the experiments. The simulations show that the experimentally observed aggregation phenomena between alumina particles are due to the silica-alumina attraction that induces an effective driving force for alumina-alumina aggregation. The experimental data for silica adsorption on alumina are very well reproduced.
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Affiliation(s)
- M Cerbelaud
- SPCTS, UMR 6638, ENSCI, CNRS, 47/73 Avenue Albert Thomas, 87065 Limoges, Cedex, France
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25
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26
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Toai TJ, Rossi G, Ferrando R. Global optimisation and growth simulation of AuCu clusters. Faraday Discuss 2008; 138:49-58; discussion 119-35, 433-4. [DOI: 10.1039/b707813g] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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27
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Gaspari R, Gliozzi A, Ferrando R. Aggregation phenomena in a system of molecules with two internal states. Phys Rev E Stat Nonlin Soft Matter Phys 2007; 76:041604. [PMID: 17995001 DOI: 10.1103/physreve.76.041604] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2007] [Revised: 09/01/2007] [Indexed: 05/25/2023]
Abstract
A model for the aggregation of molecules with two internal states is studied by kinetic Monte Carlo simulations. Molecules are represented by simple beads, discarding all stereochemical specificity. Monomers are placed in a three-dimensional lattice and diffusion processes are simulated, as well as internal state conversions of the molecules. The two internal states feature a stable (S) not assembly competent configuration, and an unstable assembly competent (A) configuration. Monomers in A state are given a higher energy if isolated, but they can reach the lowest energy level through short-range interactions between each other, so that their aggregation is promoted. Kinetics of cluster formation are examined, as well as the basic mechanisms ruling growth in our system. The simulations show that the aggregation process is preceded by a lag phase, which is followed by a fast growth phase. The duration of the lag phase is determined by the strength of the A-A interaction, whereas the time slope of the growth phase is mainly influenced by the conversion rate between internal states. The whole work has been inspired by the biological problem of amyloid aggregation, whose aggregation curves often present a sigmoidal behavior which is reproduced by the present model.
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Affiliation(s)
- R Gaspari
- Dipartimento di Fisica and INFM, Via Dodecaneso 33, Genova, I16146, Italy
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28
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Barcaro G, Fortunelli A, Rossi G, Nita F, Ferrando R. Epitaxy, truncations, and overhangs in palladium nanoclusters adsorbed on MgO(001). Phys Rev Lett 2007; 98:156101. [PMID: 17501363 DOI: 10.1103/physrevlett.98.156101] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2007] [Indexed: 05/15/2023]
Abstract
The structure of Pd clusters adsorbed on MgO(001) is determined by a combination of global-optimization methods using semiempirical potentials and density functional calculations. The transition to fcc clusters with (001) epitaxy is shown to take place in the size range 10<or=N<or=15 atoms. Truncations of vertices and basal corners in fcc epitaxial clusters proceed in parallel, while overhangs are already formed at small sizes, below 30 atoms.
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Affiliation(s)
- G Barcaro
- IPCF/CNR, G. Moruzzi 1, Pisa, I56124, Italy
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29
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Ceriotti M, Ferrando R, Montalenti F. Impact-driven effects in thin-film growth: steering and transient mobility at the Ag(110) surface. Nanotechnology 2006; 17:3556-3562. [PMID: 19661604 DOI: 10.1088/0957-4484/17/14/033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Low-energy atomic impacts on the Ag(110) surface are investigated by molecular dynamics simulations based on reliable many-body semiempirical potentials. Trajectory deflections (steering) caused by the atom-surface interaction are observed, together with impact-following, transient-mobility effects. Such processes are quantitatively analysed and their dependence on the initial kinetic energy and on the impinging direction is discussed. A clear influence of the surface anisotropy on both steering and transient mobility effects is revealed by our simulations for the simple isolated-atom case and in the submonolayer-growth regime. For the latter case, we illustrate how steering and transient mobility affect the film morphology at the nanoscale.
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Affiliation(s)
- M Ceriotti
- Dipartimento di Scienza dei Materiali della Università degli Studi di Milano-Bicocca, Via Cozzi 53, I-20125 Milano, Italy
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30
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Abstract
Experimental evidence suggests that Pd clusters on MgO, known to be good reaction catalysts, have face centered cubic (fcc) epitaxial structures. The structure of such clusters is the result of the interplay of Pd-Pd and Pd-substrate bonds, the former inclined to favor icosahedral (Ih) and decahedral (Dh)-like structures, the latter leading to place Pd atoms on top of oxygen sites, according to an epitaxial stacking. This paper shows the results of a basin-hopping global optimization procedure applied to free and MgO-supported Pd clusters in the size range 10 < or = N < or = 120. Pd-MgO interactions are modeled by an analytical function fitted to ab initio results, while Pd-Pd interactions are modeled by a semiempirical potential. Besides the tight-binding Rosato-Guillopé-Legrand (RGL) potential, we have adopted a modified version of RGL that better reproduces the experimental surface energy of palladium, modifying the attractive part of Pd atoms potential energy. We have compared the two potential models, and as a result, the RGL potential favors clusters with epitaxial arrangements, so that cluster structures are epitaxial fcc in almost all the size ranges considered. On the contrary, the alternative potential model preserves some Ih-like characteristics typical of the free Pd clusters, and it suggests that a transition size from Ih-like to epitaxial structures can take place at about 100 atoms.
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Affiliation(s)
- G Rossi
- Dipartimento di Fisica, INFM and IMEM/CNR, Via Dodecaneso 33, Genova I16146, Italy
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31
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Abstract
The diffusion of small palladium clusters on MgO(100) is theoretically investigated. It is found that small clusters can diffuse even faster than isolated adatoms by a variety of mechanisms (some of which are novel), such as dimer rotation, trimer walking, tetramer rolling, and sliding. The consequences of the diffusion of small clusters on the growth of Pd aggregates on MgO(100) are investigated, and it is shown that fast mobility of clusters larger than a single atom is essential to bring the theoretical results into agreement with the outcome of molecular beam epitaxy experiments.
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Affiliation(s)
- G Barcaro
- IPCF/CNR, Via Alfieri 1, Ghezzano, I56010, Italy
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32
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Abstract
We show by molecular dynamics simulations that the melting temperature of clusters can be tuned by selective doping. In fact, a single Ni or Cu impurity in Ag icosahedral clusters considerably increases the melting temperature even for sizes of more than a hundred atoms. The upward shift is correlated to the strain relaxation induced by a small central impurity in icosahedral clusters.
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Affiliation(s)
- C Mottet
- CRMCN/CNRS, Campus de Luminy, Case 913, 13288 Marseille Cedex 9, France
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33
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Rossi G, Rapallo A, Mottet C, Fortunelli A, Baletto F, Ferrando R. Magic polyicosahedral core-shell clusters. Phys Rev Lett 2004; 93:105503. [PMID: 15447416 DOI: 10.1103/physrevlett.93.105503] [Citation(s) in RCA: 155] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2004] [Indexed: 05/24/2023]
Abstract
A new family of magic cluster structures is found by genetic global optimization, whose results are confirmed by density functional calculations. These clusters are Ag-Ni and Ag-Cu nanoparticles with an inner Ni or Cu core and an Ag external shell, as experimentally observed for Ag-Ni, and present a polyicosahedral character. The interplay of the core-shell chemical ordering with the polyicosahedral structural arrangement gives high-symmetry clusters of remarkable structural, thermodynamic, and electronic stability, which can have high melting points (they melt higher than pure clusters of the same size), large energy gaps, and (in the case of Ag-Ni) nonzero magnetic moments.
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Affiliation(s)
- G Rossi
- INFM and IMEM/CNR, Dipartimento di Fisica, Via Dodecaneso 33, Genova, I16146, Italy
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34
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Aprà E, Baletto F, Ferrando R, Fortunelli A. Amorphization mechanism of icosahedral metal nanoclusters. Phys Rev Lett 2004; 93:065502. [PMID: 15323642 DOI: 10.1103/physrevlett.93.065502] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2004] [Indexed: 05/24/2023]
Abstract
The amorphization mechanism of icosahedral Pt nanoclusters is investigated by a combination of molecular dynamics simulations and density functional calculations. A general mechanism for amorphization, involving rosettelike structural transformations at fivefold vertices, is proposed. In the rosette, a fivefold vertex is transformed into a hexagonal ring. We show that, for icosahedral Pt nanoclusters, this transformation is associated with an energy gain, so that their most favorable structures have a low symmetry even at icosahedral magic numbers, and that the same mechanism underlies the formation of amorphous structures in gold.
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Affiliation(s)
- E Aprà
- William R Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, USA
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35
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Braun OM, Ferrando R, Tommei GE. Stimulated diffusion of an adsorbed dimer. Phys Rev E Stat Nonlin Soft Matter Phys 2003; 68:051101. [PMID: 14682782 DOI: 10.1103/physreve.68.051101] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2003] [Indexed: 05/24/2023]
Abstract
The mobility and the diffusivity of a dimer (two atoms coupled by an elastic spring) in a periodic substrate potential under the action of the dc and ac external forces are studied. It is shown that the dimer diffusivity may be strongly enhanced due to driving.
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Affiliation(s)
- O M Braun
- Institute of Physics, National Academy of Sciences of Ukraine, 03650 Kiev, Ukraine.
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36
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Abstract
We show by molecular dynamics simulations on three systems (B/A=Pd/Ag, Cu/Ag, and Ni/Ag) that three-shell metallic nanoparticles made by a core of a metal A, an intermediate shell of metal B and an external shell of metal A (A-B-A nanoparticles) can be grown by deposition of B atoms onto an A core. The growth of the intermediate B shell is triggered by the fact that the most favorable positions for isolated B impurities inside A clusters are located just one layer below the cluster surface.
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Affiliation(s)
- F Baletto
- INFM and IMEM/CNR, Dipartimento di Fisica dell'Università di Genova, via Dodecaneso 33, 16146 Genova, Italy
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37
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Abstract
We analyze a probability of atomic jumps for more than one lattice spacing in activated surface diffusion. First, we studied a role of coupling between the x and y degrees of freedom for the diffusion in a two-dimensional substrate potential. Simulation results show that in the underdamped limit the average jump length <lambda> scales with the damping coefficient eta as <lambda> proportional, variant eta(-sigma(lambda)) with 1/2<or=sigma(lambda) less, similar 2/3, so that the diffusion coefficient behaves as D proportional, variant eta(-sigma) with 0<or=sigma less, similar 1/3. Second, we introduced a realistic friction coefficient for the phonon damping mechanism and developed the technique for Langevin equation with a velocity-dependent friction coefficient. The study of diffusion in this model shows that long jumps play an essential role for diffusing atoms of small masses, especially in two limiting cases, in the case of a large Debye frequency of the substrate, when the rate of phonon damping is low, and in the case of a small Debye frequency, when the one-phonon damping mechanism is ineffective.
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Affiliation(s)
- O M Braun
- Institute of Physics, National Ukrainian Academy of Sciences, 03650 Kiev, Ukraine.
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38
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Zandrino F, Benzi L, Ferretti ML, Ferrando R, Reggiani G, Musante F. Multislice CT cholangiography without biliary contrast agent: technique and initial clinical results in the assessment of patients with biliary obstruction. Eur Radiol 2002; 12:1155-61. [PMID: 11976862 DOI: 10.1007/s00330-001-1188-y] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2001] [Revised: 08/21/2001] [Accepted: 09/14/2001] [Indexed: 12/18/2022]
Abstract
Our objective was to describe our technique for multislice CT cholangiography without cholangiographic contrast agent, and to present our preliminary clinical results. Thirty-seven patients with suspected biliary obstruction were studied. A multislice CT unit was used with the following technical parameters: 2.5-mm collimation; 7.5-mm/s table speed; pitch 6; 0.8-s rotation time; 300 mA; 120 kVp; 18- to 24-s scan time; scan volume ranging from the hepatic dome to below the pancreatic head; 70-s delay after injection of 150 ml of iodinated contrast agent at 4 ml/s. No biliary contrast material was given; oral iodinated contrast agent was administered to opacify bowel loops. Axial, multiplanar reformatted, and minimum intensity projection images were evaluated. The CT findings were compared with the gold standard techniques: endoscopic retrograde cholangiography (ERCP) in 30 patients, percutaneous transhepatic cholangiography in 5, and intraoperative cholangiography in 2. In 5 patients with ampullary lesions biopsy was made during ERCP, 9 underwent surgery, and 11 US-guided fine-needle aspiration. Bile ducts appeared hypodense within the surrounding enhanced structures. Regarding the site of obstruction, agreement between multislice CT and conventional cholangiography was observed in all cases. One patient presented negative findings on both CT and ERCP. In 31 of 36 (86%) patients, multislice CT cholangiography without cholangiographic contrast agent correctly assessed the cause of bile duct obstruction. Multislice CT cholangiography without cholangiographic contrast agent seems to be a promising diagnostic tool in the assessment of patients with bile duct obstruction.
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Affiliation(s)
- F Zandrino
- Department of Radiology, Azienda Ospedaliera SS Antonio e Biagio e C Arrigo, Alessandria, Italy.
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39
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40
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Baletto F, Ferrando R, Fortunelli A, Montalenti F, Mottet C. Crossover among structural motifs in transition and noble-metal clusters. J Chem Phys 2002. [DOI: 10.1063/1.1448484] [Citation(s) in RCA: 399] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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41
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Abstract
Molecular dynamics simulations of the growth of nanoclusters of C60 provide convincing evidence that experimental magic numbers, which are associated with structures based on Mackay icosahedra, are of kinetic origin. This finding resolves a long-standing contradiction between the experimental observations and the theoretically predicted most stable structures. Our results show that, even if a sticky intermolecular potential energetically disfavors icosahedral structures, the latter are frequently produced because the stickiness of the potential itself enhances kinetic trapping phenomena.
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Affiliation(s)
- F Baletto
- INFM and CFSBT/CNR, Dipartimento di Fisica dell'Università di Genova, via Dodecaneso 33, 16146 Genova, Italy
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42
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Carceller E, Salas J, Merlos M, Giral M, Ferrando R, Escamilla I, Ramis J, García-Rafanell J, Forn J. Novel azo derivatives as prodrugs of 5-aminosalicylic acid and amino derivatives with potent platelet activating factor antagonist activity. J Med Chem 2001; 44:3001-13. [PMID: 11520209 DOI: 10.1021/jm010852p] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
This paper describes the synthesis of a series of azo compounds able to deliver 5-aminosalicylic acid (5-ASA) and a potent platelet activating factor (PAF) antagonist in a colon-specific manner for the purpose of treating ulcerative colitis. We found it possible to add an amino group on the aromatic moiety of our reported 1-[(1-acyl-4-piperidyl)methyl]-1H-2-methylimidazo[4,5-c]pyridine derivatives or on British Biotech compounds BB-882 and BB-823 maintaining a high level of activity as PAF antagonist. A selected compound UR-12715 (49c) showed an IC(50) of 8 nM in the in vitro PAF-induced aggregation assay, and an ID(50) of 29 microg/kg in the in vivo PAF-induced hypotension test in normotensive rats. Through attachment of 49c to the 5-ASA via azo functionality we obtained UR-12746 (70). Pharmacokinetics experiments with [14C]-70 allow us to reach the following conclusions, critical in the design of these new prodrugs of 5-ASA. Neither the whole molecule 70 nor the carrier 49c were absorbed after oral administration of [14C]-70 in rat as was demonstrated by the absence of plasma levels of radioactivity and the high recovery of it in feces. Effective cleavage of azo bond (84%) by microflora in the colon is achieved. These facts ensure high topical concentrations of 5-ASA and 49c in the colon. Additionally, 70 exhibited a potent anticolitic effect in the trinitrobenzenesulfonic acid-induced colitis model in the rat. This profile suggests that UR-12746 (70) provides an attractive new approach to the treatment of ulcerative colitis.
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Affiliation(s)
- E Carceller
- Research Center, J. Uriach & Cía.S.A., Degà Bahí 59-67, 08026 Barcelona, Spain.
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44
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Ordoñez CL, Khashayar R, Wong HH, Ferrando R, Wu R, Hyde DM, Hotchkiss JA, Zhang Y, Novikov A, Dolganov G, Fahy JV. Mild and moderate asthma is associated with airway goblet cell hyperplasia and abnormalities in mucin gene expression. Am J Respir Crit Care Med 2001; 163:517-23. [PMID: 11179133 DOI: 10.1164/ajrccm.163.2.2004039] [Citation(s) in RCA: 409] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Excessive airway mucus is an important cause of morbidity and mortality in asthma, but the relationship between accumulation of mucus and goblet cell size, number, and function is incompletely understood. To address these questions, stored mucin in the epithelium and goblet cell size and number were measured morphometrically, and mucin gene expression was measured by polymerase chain reaction and immunohistochemistry in endobronchial biopsies from 13 subjects with mild and moderate asthma and from 12 healthy control subjects. Secreted mucin was measured in induced sputum. We found that stored mucin in the airway epithelium was three times higher than normal in the subjects with asthma (p < 0.005). Goblet cell size was similar in both groups, but goblet cell number was significantly higher in the subjects with asthma (93,043 +/- 15,824 versus 41,959 +/- 9,230/mm3, p < 0.05). In mild asthma (FEV1 > or = 80% pred, n = 7), the level of stored mucin was as high as in moderate asthma (FEV1 < 80% pred, n = 6), but the level of secreted mucin was significantly lower (28.4 +/- 6.3 versus 73.5 +/- 47.5 microg/ml, p < 0.05). Secreted mucin was inversely correlated with stored mucin for the whole asthma group (rs = -0.78, p = 0.007). MUC5AC was the predominant mucin gene expressed in healthy subjects and subjects with asthma, and MUC5AC protein was increased in the subjects with asthma. We conclude that even mild asthma is associated with goblet cell hyperplasia and increased stored mucin in the airway epithelium, whereas moderate asthma is associated with increased stored mucin and secreted mucin. These findings suggest that acute degranulation of hyperplastic goblet cells may represent a mechanism for asthma exacerbations in mild and moderate asthma and that chronic degranulation of goblet cells may contribute to chronic airway narrowing in moderate asthma.
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Affiliation(s)
- C L Ordoñez
- Department of Pediatrics and Cardiovascular Research Institute, University of California at San Francisco, San Francisco, California 94143, USA
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45
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Abstract
To determine whether the denudation of the bronchial epithelium observed in endobronchial biopsies from asthmatic subjects is a true pathologic feature or an artifact of tissue sampling, we analyzed epithelial integrity in bronchial biopsies from 14 subjects with mild and moderate asthma and 12 healthy subjects. In each subject, 4 to 8 bronchial biopsies were taken from large airways during bronchoscopy, fixed in 4% paraformaldehyde, embedded in glycomethacrylate, cut into 2-microM sections, and stained with toluidine blue. A x4 image of each biopsy was copied to a computer file using a video camera, and lines were drawn and measured along the basement membrane underlying areas completely denuded of overlying epithelium, areas covered by a single layer of basal cells, and areas of intact epithelium. We found that the percentage of basement membrane that was denuded of epithelium was similar in the healthy and asthmatic subjects (14.8 +/- 11.8 versus 11.4 +/- 9.8% respectively, p = 0.38); the percentage of basement membrane that was covered by a single layer of basal cells was also similar in the two groups (46.4 +/- 11.0 versus 54.5 +/- 9.8%, respectively, p = 0. 11). In the asthmatic subjects, we found no significant correlation between the percentage of basement membrane covered by denuded epithelium or by a single layer of basal cells and the FEV(1) percentage of predicted or the PC(20) methacholine. We conclude that denudation of bronchial epithelium in endobronchial biopsies from asthmatic subjects with stable mild and moderate disease is an artifact of tissue sampling and is not a true pathologic feature of the disease, and that the extent of airway epithelial denudation is not correlated with the severity of airway narrowing or the severity of bronchial hyperresponsiveness.
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Affiliation(s)
- C Ordoñez
- Department of Pediatrics, University of California, San Francisco, San Francisco, California 94143, USA
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46
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Ferrando R, Rollandi G, Derchi LE, Quilici P, Tornago S. [Post-traumatic costal fibrous dysplasia. A case]. Radiol Med 2000; 100:279-81. [PMID: 11155456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
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47
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Abstract
Members of the integrin family of adhesion receptors mediate both cell-cell and cell-matrix interactions and have been shown to play vital roles in embryonic development, wound healing, metastasis, and other biological processes. The integrin alpha9beta1 is a receptor for the extracellular matrix proteins osteopontin and tenacsin C and the cell surface immunoglobulin vascular cell adhesion molecule-1. This receptor is widely expressed in smooth muscle, hepatocytes, and some epithelia. To examine the in vivo function of alpha9beta1, we have generated mice lacking expression of the alpha9 subunit. Mice homozygous for a null mutation in the alpha9 subunit gene appear normal at birth but develop respiratory failure and die between 6 and 12 days of age. The respiratory failure is caused by an accumulation of large volumes of pleural fluid which is rich in triglyceride, cholesterol, and lymphocytes. alpha9(-/-) mice also develop edema and lymphocytic infiltration in the chest wall that appears to originate around lymphatics. alpha9 protein is transiently expressed in the developing thoracic duct at embryonic day 14, but expression is rapidly lost during later stages of development. Our results suggest that the alpha9 integrin is required for the normal development of the lymphatic system, including the thoracic duct, and that alpha9 deficiency could be one cause of congenital chylothorax.
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Affiliation(s)
- X Z Huang
- Lung Biology Center, Center for Occupational and Environmental Health, Cardiovascular Research Institute, San Francisco, California 94143-0854, USA
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48
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49
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Baletto F, Mottet C, Ferrando R. Reentrant morphology transition in the growth of free silver nanoclusters. Phys Rev Lett 2000; 84:5544-5547. [PMID: 10990990 DOI: 10.1103/physrevlett.84.5544] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2000] [Indexed: 05/23/2023]
Abstract
The growth of free silver nanoclusters is studied by molecular dynamics simulations, from a small seed up to sizes N approximately 150. It is shown that the final outcome of the growth process depends crucially on the growth conditions (deposition flux straight phi and temperature T). A reentrant morphology transition is obtained: at intermediate values of T and straight phi a "decahedral window" is found; the window is surrounded by regimes where icosahedra are preferentially grown.
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Affiliation(s)
- F Baletto
- INFM and CFSBT/CNR, Dipartimento di Fisica dell'Universita di Genova, via Dodecaneso 33, 16146 Genova, Italy
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50
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Ferrando R, Tornago S, Desalvo L. [Iatrogenic diverticulum at the level of the Douglas pouch in patient treated with Longo hemorrhoidectomy. A case report]. Radiol Med 2000; 99:480-2. [PMID: 11262831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Affiliation(s)
- R Ferrando
- Cattedra R, R, DICMI Università di Genova
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