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Parvizi-Bahktar P, Mendez-Campos J, Raju L, Khalique NA, Jubeli E, Larsen H, Nicholson D, Pungente MD, Fyles TM. Structure–activity correlation in transfection promoted by pyridinium cationic lipids. Org Biomol Chem 2016; 14:3080-90. [DOI: 10.1039/c6ob00041j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The efficiency of transfection of a plasmid DNA promoted by a series of pyridinium lipids is correlated with molecular parameters of the lipids.
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Tan S(J, Do DD, Nicholson D. An efficientmethod to determine chemical potential of mixtures in the isothermal and isobaric bulk phase with kineticMonte Carlo simulation. Mol Phys 2015. [DOI: 10.1080/00268976.2015.1090634] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Nguyen VT, Tan SJ, Do D, Nicholson D. Application of kinetic Monte Carlo method to the vapour–liquid equilibria of associating fluids and their mixtures. MOLECULAR SIMULATION 2015. [DOI: 10.1080/08927022.2015.1067809] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Phadungbut P, Fan C, Do D, Nicholson D, Tangsathitkulchai C. Determination of absolute adsorption for argon on flat surfaces under sub- and supercritical conditions. Colloids Surf A Physicochem Eng Asp 2015. [DOI: 10.1016/j.colsurfa.2015.04.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Bruschi L, Mistura G, Phadungbut P, Do DD, Nicholson D, Mayamei Y, Lee W. Adsorption on ordered and disordered duplex layers of porous anodic alumina. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:4895-4905. [PMID: 25871845 DOI: 10.1021/acs.langmuir.5b00716] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We have carried out systematic experiments and numerical simulations of the adsorption on porous anodic aluminum oxide (AAO) duplex layers presenting either an ordered or a disordered interconnecting interface between the large (cavity) and small (constriction) sections of the structured pores. Selective blocking of the pore openings resulted in three different pore topologies: open structured pores, funnel pores, and ink-bottle pores. In the case of the structured pores having an ordered interface, the adsorption isotherms present a rich phenomenology characterized by the presence of two steps in the condensation branch and the opening of one (two) hysteresis loops during evaporation for the ink-bottle (open and funnel) pores. The isotherms can be obtained by summing the isotherms measured on uniform pores having the dimensions of the constrictions or of the cavities. The numerical analysis of the three different pore topologies indicates that the shape of the junction between the two pore sections is only important for the adsorption branch. In particular, a conic junction which resembles that of the AAO pores represents the experimental isotherms for the open and funnel pores better, but the shape of the junction in the ink bottle pores does not matter. The isotherms for the duplex layers with a disordered interface display the same general features found for the ordered duplex layers. In both cases, the adsorption branches coincide and have two steps which are shifted to lower relative pressures compared to those for the ordered duplex. Furthermore, the desorption branches comprise hysteresis loops much wider than those of the ordered duplex layers. Overall, this study highlights the important role played by morphologies where there are interconnections between large and small pores.
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Do D, Johnathan Tan S, Zeng Y, Fan C, Nguyen VT, Horikawa T, Nicholson D. The interplay between molecular layering and clustering in adsorption of gases on graphitized thermal carbon black – Spill-over phenomenon and the important role of strong sites. J Colloid Interface Sci 2015; 446:98-113. [DOI: 10.1016/j.jcis.2015.01.028] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 01/13/2015] [Accepted: 01/13/2015] [Indexed: 11/27/2022]
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Zeng Y, Do DD, Nicholson D. Existence of ultrafine crevices and functional groups along the edge surfaces of graphitized thermal carbon black. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:4196-4204. [PMID: 25797845 DOI: 10.1021/acs.langmuir.5b00667] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Adsorption of different gases on graphitized thermal carbon black (GTCB) has been studied with a new molecular model to examine the consequences of micropore crevices and functional groups at the junctions between adjacent basal planes. Adsorption was simulated in the Grand Canonical Monte Carlo ensemble and the theoretical Henry constants were calculated by Monte Carlo volume integration over the Boltzmann factor of the solid-fluid potential. The simulation results are in good agreement with high-resolution experimental isotherms for argon on mineralogical graphite measured by Lopez-Gonzalez et al.1 From detailed inspection of the argon isotherms at extremely low coverages, we find two distinct Henry law regions, separated by a plateau (suggesting saturation of the stronger sites) that spans over a few decades of pressure. The first Henry law region is attributed to adsorption in the ultrafine crevices at the junctions between two adjacent basal planes, and the second region corresponds to adsorption on the basal plane, as confirmed by the theoretical Henry constant. The simulated isosteric heat and snapshots of molecular configurations show that argon adsorbs preferentially in the ultrafine crevices where there is a deep potential well due to overlap from the opposite pore walls. Similar behavior was found for other nonassociating fluids (Ar, N2, and CO2); however, for associating fluids (NH3 and H2O), the strong sites for adsorption and nucleation come from the combined effects of functional groups and ultrafine crevices, since the latter cannot alone account for the observed adsorption.
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Phadungbut P, Do D, Nicholson D, Tangsathitkulchai C. On the phase transition of argon adsorption in an open end slit pore—Effects of temperature and pore size. Chem Eng Sci 2015. [DOI: 10.1016/j.ces.2014.12.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Fan C, Zeng Y, Do D, Nicholson D. A molecular simulation study of adsorption and desorption in closed end slit pores: Is there a hysteresis loop? Chem Eng Sci 2015. [DOI: 10.1016/j.ces.2014.08.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Klomkliang N, Do DD, Nicholson D. Hysteresis loop and scanning curves of argon adsorption in closed-end wedge pores. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:12879-12887. [PMID: 25314672 DOI: 10.1021/la5035992] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The hysteresis loop and scanning curves for argon adsorbed in a wedge pore with one end closed are studied with grand canonical Monte Carlo simulation. We have found multiple hysteresis loops for pores with either the narrow end or the wider end closed. In pores with the narrow end closed, adsorption and desorption exhibits a two-stage sequence of rapid change, followed by a gradual change in adsorbate density. The pore can be divided into zones of commensurate packing and junctions of incommensurate packing. A striking feature is that the sequence of these two stages is opposite for the adsorption and desorption processes. This can be explained by cohesion in the adsorbate, in which a steep condensation process is associated with the zones and a steep evaporation process is associated with the junctions between them. For pores with the wider end closed, the processes of adsorption and desorption from various zones are correlated with each other. In pores with the narrow end closed, the scanning curves trace reversibly along the segment of the isotherm, where the isotherm shows gradual change, and when the scanning curve reaches a point between the gradual change segment and the sharp change segment, the scanning curve crosses from one boundary of the hysteresis loop to the corresponding point on the other boundary. This indicates that the condensation and evaporation states are not affected by scanning but that, in scanning across the hysteresis loop, the adsorbate passes through a sequence of metastable states as the distribution of density is rearranged, without any significant change in the overall density. In contrast, for pores with the wider end closed, both the descending curve from a partially filled pore and the ascending curve are identical to the desorption branch of the corresponding pore with its narrow end closed.
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Kintz P, Nicholson D. Testing for ethanol markers in hair: Discrepancies after simultaneous quantification of ethyl glucuronide and fatty acid ethyl esters. Forensic Sci Int 2014; 243:44-6. [DOI: 10.1016/j.forsciint.2014.03.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 02/14/2014] [Accepted: 03/12/2014] [Indexed: 11/28/2022]
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Phadungbut P, Nguyen VT, Do D, Nicholson D, Tangsathitkulchai C. On the phase transition in a monolayer adsorbed on graphite at temperatures below the 2D-critical temperature. MOLECULAR SIMULATION 2014. [DOI: 10.1080/08927022.2014.958152] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Zeng Y, Fan C, Do DD, Nicholson D. Evaporation from an Ink-Bottle Pore: Mechanisms of Adsorption and Desorption. Ind Eng Chem Res 2014. [DOI: 10.1021/ie500215x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Saad W, Khaja M, Schwaner S, Davies M, Nicholson D, Pelletier S, Al-Osaimi A, Angle J, Matsumoto A. Portal vein stenosis in adult whole graft liver transplant recipients: primary management with transhepatic angioplasty. J Vasc Interv Radiol 2014. [DOI: 10.1016/j.jvir.2013.12.415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Nguyen VT, Do D, Nicholson D. Reconciliation of different simulation methods in the determination of the equilibrium branch for adsorption in pores. MOLECULAR SIMULATION 2014. [DOI: 10.1080/08927022.2013.829229] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Fan C, Do D, Nicholson D. On the existence of a hysteresis loop in open and closed end pores. MOLECULAR SIMULATION 2014. [DOI: 10.1080/08927022.2013.869805] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Fan C, Zeng Y, Do DD, Nicholson D. An undulation theory for condensation in open end slit pores: critical hysteresis temperature & critical hysteresis pore size. Phys Chem Chem Phys 2014; 16:12362-73. [DOI: 10.1039/c4cp00848k] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Carty C, Cronin N, Nicholson D, Lichtwark G, Mills P, Kerr G, Cresswell A, Barrett R. Reactive stepping behaviour in response to forward loss of balance predicts future falls in community-dwelling older adults. J Sci Med Sport 2013. [DOI: 10.1016/j.jsams.2013.10.053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Nguyen PT, Do D, Nicholson D. Pore connectivity and hysteresis in gas adsorption: A simple three-pore model. Colloids Surf A Physicochem Eng Asp 2013. [DOI: 10.1016/j.colsurfa.2013.03.028] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Nguyen VT, Fan C, Razak MA, Do D, Nicholson D, Ustinov E. Development of kinetic Monte Carlo and Bin-Monte Carlo schemes for simulation of mixtures – vapor–liquid equilibria & adsorption. Chem Eng Sci 2013. [DOI: 10.1016/j.ces.2013.07.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Fan C, Do DD, Nicholson D. Condensation and Evaporation in Capillaries with Nonuniform Cross Sections. Ind Eng Chem Res 2013. [DOI: 10.1021/ie402549z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Liu Z, Nguyen VT, Do D, Nicholson D. A Monte Carlo study of equilibrium transition in finite cylindrical pores. MOLECULAR SIMULATION 2013. [DOI: 10.1080/08927022.2013.829230] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Klomkliang N, Do DD, Nicholson D. On the hysteresis loop and equilibrium transition in slit-shaped ink-bottle pores. ADSORPTION 2013. [DOI: 10.1007/s10450-013-9569-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Nickmand Z, Do DD, Nicholson D, Aghamiri SF, Khozanie MRT, Sabzyan H. GCMC simulation of argon adsorption in wedge shaped mesopores of finite length. ADSORPTION 2013. [DOI: 10.1007/s10450-013-9565-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Fan C, Do D, Nicholson D, Ustinov E. Chemical potential, Helmholtz free energy and entropy of argon with kinetic Monte Carlo simulation. Mol Phys 2013. [DOI: 10.1080/00268976.2013.798696] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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