119 resultados para integrable 3-wave interactions

em Queensland University of Technology - ePrints Archive


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Bronfenbrenner.s Bioecological Model, expressed as the developmental equation, D f PPCT, is the theoretical framework for two studies that bring together diverse strands of psychology to study the work-life interface of working adults. Occupational and organizational psychology is focused on the demands and resources of work and family, without emphasising the individual in detail. Health and personality psychology examine the individual but without emphasis on the individual.s work and family roles. The current research used Bronfenbrenner.s theoretical framework to combine individual differences, work and family to understand how these factors influence the working adult.s psychological functioning. Competent development has been defined as high well-being (measured as life satisfaction and psychological well-being) and high work engagement (as work vigour, work dedication and absorption in work) and as the absence of mental illness (as depression, anxiety and stress) and the absence of burnout (as emotional exhaustion, cynicism and professional efficacy). Study 1 and 2 were linked, with Study 1 as a cross-sectional survey and Study 2, a prospective panel study that followed on from the data used in Study1. Participants were recruited from a university and from a large public hospital to take part in a 3-wave, online study where they completed identical surveys at 3-4 month intervals (N = 470 at Time 1 and N = 198 at Time 3). In Study 1, hierarchical multiple regressions were used to assess the effects of individual differences (Block 1, e.g. dispositional optimism, coping self-efficacy, perceived control of time, humour), work and family variables (Block 2, e.g. affective commitment, skill discretion, work hours, children, marital status, family demands) and the work-life interface (Block 3, e.g. direction and quality of spillover between roles, work-life balance) on the outcomes. There were a mosaic of predictors of the outcomes with a group of seven that were the most frequent significant predictors and which represented the individual (dispositional optimism and coping self-efficacy), the workplace (skill discretion, affective commitment and job autonomy) and the work-life interface (negative work-to-family spillover and negative family-to-work spillover). Interestingly, gender and working hours were not important predictors. The effects of job social support, generally and for work-life issues, perceived control of time and egalitarian gender roles on the outcomes were mediated by negative work-to-family spillover, particularly for emotional exhaustion. Further, the effect of negative spillover on depression, anxiety and work engagement was moderated by the individual.s personal and workplace resources. Study 2 modelled the longitudinal relationships between the group of the seven most frequent predictors and the outcomes. Using a set of non-nested models, the relative influences of concurrent functioning, stability and change over time were assessed. The modelling began with models at Time 1, which formed the basis for confirmatory factor analysis (CFA) to establish the underlying relationships between the variables and calculate the composite variables for the longitudinal models. The CFAs were well fitting with few modifications to ensure good fit. However, using burnout and work engagement together required additional analyses to resolve poor fit, with one factor (representing a continuum from burnout to work engagement) being the only acceptable solution. Five different longitudinal models were investigated as the Well-Being, Mental Distress, Well-Being-Mental Health, Work Engagement and Integrated models using differing combinations of the outcomes. The best fitting model for each was a reciprocal model that was trimmed of trivial paths. The strongest paths were the synchronous correlations and the paths within variables over time. The reciprocal paths were more variable with weak to mild effects. There was evidence of gain and loss spirals between the variables over time, with a slight net gain in resources that may provide the mechanism for the accumulation of psychological advantage over a lifetime. The longitudinal models also showed that there are leverage points at which personal, psychological and managerial interventions can be targeted to bolster the individual and provide supportive workplace conditions that also minimise negative spillover. Bronfenbrenner.s developmental equation has been a useful framework for the current research, showing the importance of the person as central to the individual.s experience of the work-life interface. By taking control of their own life, the individual can craft a life path that is most suited to their own needs. Competent developmental outcomes were most likely where the person was optimistic and had high self-efficacy, worked in a job that they were attached to and which allowed them to use their talents and without too much negative spillover between their work and family domains. In this way, individuals had greater well-being, better mental health and greater work engagement at any one time and across time.

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The excitation of pairs of electron surface waves via nonresonant decay of plasma waves incident onto a solid surface is studied in the context of controlling the interaction of pulsed electromagnetic radiation with plasma-exposed solid surfaces. The role of the plasma-exposed surfaces in nonlinear heating of the plasma edge and related power transfer is discussed. It is shown that the maximum efficiency of the power transfer at solid surfaces with dielectric permittivity εd <3 corresponds to the resonant two-surface wave decay. On the other hand, for solids with εd >3 the maximum power transfer efficiency is achieved through nonresonant excitation of the quasistatic surface waves. In this case the plasma waves generated by external radiation dissipate their energy into the plasma periphery most effectively.

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Controlled interaction of high-power pulsed electromagnetic radiation with plasma-exposed solid surfaces is a major challenge in applications spanning from electron beam accelerators in microwave electronics to pulsed laser ablation-assisted synthesis of nanomaterials. It is shown that the efficiency of such interaction can be potentially improved via an additional channel of wave power dissipation due to nonlinear excitation of two counterpropagating surface waves, resonant excitations of the plasma-solid system.Physics.

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This study aimed to develop a 3-Dimensional (D) hydrogel system for the co-culture of autologous human renal and immune cells. Previous studies have shown that human renal epithelial cells are able to modulate autologous immune cell responses. However, these studies were undertaken in a standard 2D culture system. The 3D model was developed to re-capitulate these observations within a more physiological relevant in vivo like environment.

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The electrochemical characteristics of a series of heteroleptic tris(phthalocyaninato) complexes with identical rare earths or mixed rare earths (Pc)M(OOPc)M(OOPc) [M = Eu...Lu, Y; H2Pc = unsubstituted phthalocyanine, H2(OOPc) = 3,4,12,13,21,22,30,31-octakis(octyloxy)phthalocyanine] and (Pc)Eu(OOPc)Er(OOPc) have been recorded and studied comparatively by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in CH2Cl2 containing 0.1 M tetrabutylammonium perchlorate (TBAP). Up to five quasi-reversible one-electron oxidations and four one-electron reductions have been revealed. The half-wave potentials of the first, second and fifth oxidations depend on the size of the metal center, but the fifth changes in the opposite direction to that of the first two. Moreover, the difference in redox potentials of the first oxidation and first reduction for (Pc)M(OOPc)M(OOPc), 0.85−0.98 V, also decreases linearly along with decreasing rare earth ion radius, clearly showing the rare earth ion size effect and indicating enhanced π−π interactions in the triple-deckers connected by smaller lanthanides. This order follows the red-shift seen in the lowest energy band of triple-decker compounds. The electronic differences between the lanthanides and yttrium are more apparent for triple-decker sandwich complexes than for the analogous double-deckers. By comparing triple-decker, double-decker and mononuclear [ZnII] complexes containing the OOPc ligand, the HOMO−LUMO gap has been shown to contract approximately linearly with the number of stacked phthalocyanine ligands.

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The electrochemistry of homoleptic substituted phthalocyaninato rare earth double-decker complexes M(TBPc)2 and M(OOPc)2 [M = Y, La...Lu except Pm; H2TBPc = 3(4),12(13),21(22),30(31)-tetra-tert-butylphthalocyanine, H2OOPc = 3,4,12,13,21,22,30,31-octakis(octyloxy)phthalocyanine] has been comparatively studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in CH2Cl2 containing 0.1 M tetra-n-butylammonium perchlorate (TBAP). Two quasi-reversible one-electron oxidations and three or four quasi-reversible one-electron reductions have been revealed for these neutral double-deckers of two series of substituted complexes, respectively. For comparison, unsubstituted bis(phthalocyaninato) rare earth analogues M(Pc)2 (M = Y, La...Lu except Pm; H2Pc = phthalocyanine) have also been electrochemically investigated. Two quasi-reversible one-electron oxidations and up to five quasi-reversible one-electron reductions have been revealed for these neutral double-decker compounds. The three bis(phthalocyaninato)cerium compounds display one cerium-centered redox wave between the first ligand-based oxidation and reduction. The half-wave potentials of the first and second oxidations and first reduction for double-deckers of the tervalent rare earths depend on the size of the metal center. The difference between the redox potentials of the second and third reductions for MIII(Pc)2, which represents the potential difference between the first oxidation and first reduction of [MIII(Pc)2]−, lies in the range 1.08−1.37 V and also gradually diminishes along with the lanthanide contraction, indicating enhanced π−π interactions in the double-deckers connected by the smaller, lanthanides. This corresponds well with the red-shift of the lowest energy band observed in the electronic absorption spectra of reduced double-decker [MIII(Pc′)2]− (Pc′ = Pc, TBPc, OOPc).

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Mixtures of Regioregular Poly(3-hexyl-thiophene) (rrP3HT) and multi wall carbon nanotubes have been investigated by Scanning Tunneling Microscopy in Ultra High Vacuum. Carbon nanotubes covered by rrP3HT have been imaged and analyzed, providing a clear evidence that this polymer self assembles on the nanotube surface following geometrical constraints and adapting its equilibrium chain-to-chain distance. Largely spaced covered nanotubes have been analyzed to investigate the role played by nanotube chirality in the polymer wrapping, evidencing strong rrP3HT interactions along well defined directions.

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In the title compound, C8H12NO+ C7H3N2O6-, the anilinium and hydroxyl protons of the cation result in N-H...O, N-H..(O,O) and O-H...O hydrogen-bonding interactions with carboxylate O atom acceptors, forming a two-dimensional network structure. An intermolecular C-H...O interaction is also present.

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Interactions between small molecules with biopolymers e.g. the bovine serum albumin (BSA protein), are important, and significant information is recorded in the UV–vis and fluorescence spectra of their reaction mixtures. The extraction of this information is difficult conventionally and principally because there is significant overlapping of the spectra of the three analytes in the mixture. The interaction of berberine chloride (BC) and the BSA protein provides an interesting example of such complex systems. UV–vis and fluorescence spectra of BC and BSA mixtures were investigated in pH 7.4 Tris–HCl buffer at 37 °C. Two sample series were measured by each technique: (1) [BSA] was kept constant and the [BC] was varied and (2) [BC] was kept constant and the [BSA] was varied. This produced four spectral data matrices, which were combined into one expanded spectral matrix. This was processed by the multivariate curve resolution–alternating least squares method (MCR–ALS). The results produced: (1) the extracted pure BC, BSA and the BC–BSA complex spectra from the measured heavily overlapping composite responses, (2) the concentration profiles of BC, BSA and the BC–BSA complex, which are difficult to obtain by conventional means, and (3) estimates of the number of binding sites of BC.

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The binding interaction of the pesticide Isoprocarb and its degradation product, sodium 2-isopropylphenate, with bovine serum albumin (BSA) was studied by spectrofluorimetry under simulated physiological conditions. Both Isoprocarb and sodium 2-isopropylphenate quenched the intrinsic fluorescence of BSA. This quenching proceeded via a static mechanism. The thermodynamic parameters (ΔH°, ΔS° and ΔG°) obtained from the fluorescence data measured at two different temperatures showed that the binding of Isoprocarb to BSA involved hydrogen bonds and that of sodium 2-isopropylphenate to BSA involved hydrophobic and electrostatic interactions. Synchronous fluorescence spectroscopy of the interaction of BSA with either Isoprocarb or sodium 2-isopropylphenate showed that the molecular structure of the BSA was changed significantly, which is consistent with the known toxicity of the pesticide, i.e., the protein is denatured. The sodium 2-isopropylphenate, was estimated to be about 4–5 times more toxic than its parent, Isoprocarb. Synchronous fluorescence spectroscopy and the resolution of the three-way excitation–emission fluorescence spectra by the PARAFAC method extracted the relative concentration profiles of BSA, Isoprocab and sodium 2-isopropylphenate as a function of the added sodium 2-isopropylphenate. These profiles showed that the degradation product, sodium 2-isopropylphenate, displaced the pesticide in a competitive reaction with the BSA protein.

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In the structure of the title compound C8H12NO+ C7H5O6S- . H2O, from the reaction of 2-(4-aminophenyl)ethanol with 5-sulfosalicylic acid, the cations form head-to-tail hydrogen-bonded chains through C1/1(9) anilinium N+-H...O(hydroxyl} interactions while the anions also form similar but C1/1(8)-linked chains through carboxylic acid O-..O(sulfonate) interactions. The chains inter-associate through a number of N-H...O and O-H...O bridging interactions giving a two-dimensional array in the ab plane.

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The interactions of phenyldithioesters with gold nanoparticles (AuNPs) have been studied by monitoring changes in the surface plasmon resonance (SPR), depolarised light scattering, and surface enhanced Raman spectroscopy (SERS). Changes in the SPR indicated that an AuNP-phenyldithioester charge transfer complex forms in equilibrium with free AuNPs and phenyldithioester. Analysis of the Langmuir binding isotherms indicated that the equilibrium adsorption constant, Kads, was 2.3 ± 0.1 × 106 M−1, which corresponded to a free energy of adsorption of 36 ± 1 kJ mol−1. These values are comparable to those reported for interactions of aryl thiols with gold and are of a similar order of magnitude to moderate hydrogen bonding interactions. This has significant implications in the application of phenyldithioesters for the functionalization of AuNPs. The SERS results indicated that the phenyldithioesters interact with AuNPs through the C═S bond, and the molecules do not disassociate upon adsorption to the AuNPs. The SERS spectra are dominated by the portions of the molecule that dominate the charge transfer complex with the AuNPs. The significance of this in relation to the use of phenyldithioesters for molecular barcoding of nanoparticle assemblies is discussed.

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The 1:1 proton-transfer compounds of L-tartaric acid with 3-aminopyridine [3-aminopyridinium hydrogen (2R,3R)-tartrate dihydrate, C5H7N2+·C4H5O6-·2H2O, (I)], pyridine-3-carboxylic acid (nicotinic acid) [anhydrous 3-carboxypyridinium hydrogen (2R,3R)-tartrate, C6H6NO2+·C4H5O6-, (II)] and pyridine-2-carboxylic acid [2-carboxypyridinium hydrogen (2R,3R)-tartrate monohydrate, C6H6NO2+·C4H5O6-·H2O, (III)] have been determined. In (I) and (II), there is a direct pyridinium-carboxyl N+-HO hydrogen-bonding interaction, four-centred in (II), giving conjoint cyclic R12(5) associations. In contrast, the N-HO association in (III) is with a water O-atom acceptor, which provides links to separate tartrate anions through Ohydroxy acceptors. All three compounds have the head-to-tail C(7) hydrogen-bonded chain substructures commonly associated with 1:1 proton-transfer hydrogen tartrate salts. These chains are extended into two-dimensional sheets which, in hydrates (I) and (III) additionally involve the solvent water molecules. Three-dimensional hydrogen-bonded structures are generated via crosslinking through the associative functional groups of the substituted pyridinium cations. In the sheet struture of (I), both water molecules act as donors and acceptors in interactions with separate carboxyl and hydroxy O-atom acceptors of the primary tartrate chains, closing conjoint cyclic R44(8), R34(11) and R33(12) associations. Also, in (II) and (III) there are strong cation carboxyl-carboxyl O-HO hydrogen bonds [OO = 2.5387 (17) Å in (II) and 2.441 (3) Å in (III)], which in (II) form part of a cyclic R22(6) inter-sheet association. This series of heteroaromatic Lewis base-hydrogen L-tartrate salts provides further examples of molecular assembly facilitated by the presence of the classical two-dimensional hydrogen-bonded hydrogen tartrate or hydrogen tartrate-water sheet substructures which are expanded into three-dimensional frameworks via peripheral cation bifunctional substituent-group crosslinking interactions.