148 resultados para Ancillary ligand
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Introduction Sphingosine-1-phosphate receptor 1 (S1P1) is crucial for regulation of immunity and bone metabolism. This study aimed to investigate the expression of S1P1 in rat periapical lesions and its relationship with receptor activator of nuclear factor kappa B ligand (RANKL) and regulatory T (Treg) cells. Methods Periapical lesions were induced by pulp exposure in the first lower molars of 55 Wistar rats. Thirty rats were killed on days 0, 7, 14, 21, 28, and 35, and their mandibles were harvested for x-ray imaging, micro–computed tomography scanning, histologic observation, immunohistochemistry, enzyme histochemistry, and double immunofluorescence analysis. The remaining 25 rats were killed on days 0, 14, 21, 28, and 35, and mandibles were harvested for flow cytometry. Results The volume and area of the periapical lesions increased from day 0 to day 21 and then remained comparably stable after day 28. S1P1-positive cells were observed in the inflammatory periapical regions; the number of S1P1-positive cells peaked at day 14 and then decreased from day 21 to day 35. The distribution of S1P1-positive cells was positively correlated with the dynamics of RANKL-positive cells but was negatively correlated with that of Treg cells. Conclusions S1P1 expression was differentially correlated with RANKL and Treg cell infiltration in the periapical lesions and is therefore a contributing factor to the pathogenesis of such lesions.
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The structures of the isomorphous potassium and rubidium polymeric coordination complexes with 4-nitrobenzoic acid, poly[mu2-aqua-aqua-mu3-(4-nitrobenzoato)-potassium], [K(C7H4N2O2)(H2O)2]n, (I) and poly[mu3-aqua-aqua-mu5-(4-nitrobenzoato)-rubidium], [Rb(C7H4N2O2)(H2O)2]n, (II) have been determined. In (I) the very distorted KO6 coordination sphere about the K+ centres in the repeat unit comprise two bridging nitro O-atom donors, a single bridging carboxyl O-atom donor and two water molecules, one of which is bridging. In the the Rb complex (II), the same basic MO6 coordination is found in the repeat unit but is expanded to RbO9 through a slight increase in the accepted Rb-O bond length range and includes an additional Rb-O(carboxyl) bond, completing a bidentate O,O'-chelate interaction, and additional bridging Rb-Onitro) and Rb-O(water) bonds. The comparative K-O and Rb-O bond length ranges are 2.738(3)-3.002(3)Ang. (I) and 2.884(2)-3.182(2)Ang. (II). The structure of (II) is also isomorphous as well as isostructural with the known structure of the nine-coordinate caesium 4-nitrobenzoate analogue, [Cs(C7H4N2O~2~)(H~2~O)2]n, (III) in which the Cs---O range is 3.047(4)-3.338(4)Ang. In all three complexes, common basic polymeric extensions are found, including two different centrosymmetric bridging interactions through both water and nitro groups as well as extensions along c through the p-related carboxyl group, giving a two-dimensional structure in (I). In (II) and (III), three-dimensional structures are generated through additional bridges through the nitro and water O-atoms. In all structures, both water molecules are involved in similar intra-polymer O-H...O hydrogen-bonding interactions to both carboxyl as well as water O-atom acceptors. A comparison of the varied coordination behaviour of the full set of Li-Cs salts with 4-nitrobenzoic acid is also made.
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Businesses in various consumer service industries have begun to unbundle their service offerings by introducing numerous fees for products and services that were previously provided as “free.” Anecdotal evidence in the media indicates that these fees cause widespread public displeasure, frustration, and outrage. This paper develops a framework of fee acceptability, negative emotions, and dysfunctional customer behavior, which is tested using data from the airline industry. Findings identify the strongest effects on betrayal in the case of baggage fees, followed by charges for comfort. Also, betrayal has a direct effect on complaining, whereas anger mediates the relationship between betrayal and negative word of mouth.
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The use of Australian screen content in Australian schools and universities is undergoing rapid change due to digital and online distribution capacity on the supply side and digital and online affordance embedded in student cultures. This paper examines the ways in which Australian screen content and its distribution are beginning to adapt to educational usage. Issues facing content rights holders, distribution companies and emerging digital platforms reflect broad-based digital disruption patterns. Learning opportunities that can coincide with the growth in uptake of Australian screen content in Australia's education sector are not immune to the challenges posed by emerging digital consumption behaviours and issues of sustainability. At the same time, the growth in the use of digital and online screen content learning resources, under current copyright conditions, poses significant increases in the underlying cost structure for educational interests. This paper examines the innovations occurring in both the supply and the demand sides of Australian screen content and the expanded learning opportunities arising out of emerging digital affordances. Precedents in the UK are explored that demonstrate how stronger connections can be forged between nationally produced film and media content and a national curriculum. While addressing recent issues arising out of the Australian Law Review Commission's inquiry into copyright in the digital economy, the purpose of this discussion is not to assess policy debates about fair use versus fair dealing. What is clear, however, is that independent research is required that draws upon research-based evidence with an aim to better understanding the needs of the education sector against the transformative shifts taking place in digital-based learning materials and their modes of delivery.
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Modulation of protein binding specificity is important for basic biology and for applied science. Here we explore how binding specificity is conveyed in PDZ (postsynaptic density protein-95/discs large/zonula occludens-1) domains, small interaction modules that recognize various proteins by binding to an extended C terminus. Our goal was to engineer variants of the Erbin PDZ domain with altered specificity for the most C-terminal position (position 0) where a Val is strongly preferred by the wild-type domain. We constructed a library of PDZ domains by randomizing residues in direct contact with position 0 and in a loop that is close to but does not contact position 0. We used phage display to select for PDZ variants that bind to 19 peptide ligands differing only at position 0. To verify that each obtained PDZ domain exhibited the correct binding specificity, we selected peptide ligands for each domain. Despite intensive efforts, we were only able to evolve Erbin PDZ domain variants with selectivity for the aliphatic C-terminal side chains Val, Ile and Leu. Interestingly, many PDZ domains with these three distinct specificities contained identical amino acids at positions that directly contact position 0 but differed in the loop that does not contact position 0. Computational modeling of the selected PDZ domains shows how slight conformational changes in the loop region propagate to the binding site and result in different binding specificities. Our results demonstrate that second-sphere residues could be crucial in determining protein binding specificity.
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This thesis explores perspectives on the accountability of Private Ancillary Funds (PAFs), a type of Australian endowed philanthropic foundation. Privately established for a public benefit purpose, with limited formal accountability requirements, there are differing and sometimes conflicting perspectives on the nature and scope of PAF accountability. Through in-depth interviews with managers and trustees of 10 PAFs, forms and relationships of PAF accountability are uncovered. Findings reveal accountability for PAFs does not necessarily include public disclosure or transparency. However, engagement with accountability for a PAF results in greater impact and satisfaction for those involved.
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Targeted nanomedicines offer a strategy for greatly enhancing accumulation of a therapeutic within a specific tissue in animals. In this study, we report on the comparative targeting efficiency toward prostate-specific membrane antigen (PSMA) of a number of different ligands that are covalently attached by the same chemistry to a polymeric nanocarrier. The targeting ligands included a small molecule (glutamate urea), a peptide ligand, and a monoclonal antibody (J591). A hyperbranched polymer (HBP) was utilized as the nanocarrier and contained a fluorophore for tracking/analysis, whereas the pendant functional chain-ends provided a handle for ligand conjugation. Targeting efficiency of each ligand was assessed in vitro using flow cytometry and confocal microscopy to compare degree of binding and internalization of the HBPs by human prostate cancer (PCa) cell lines with different PSMA expression status (PC3-PIP (PSMA+) and PC3-FLU (PSMA−). The peptide ligand was further investigated in vivo, in which BALB/c nude mice bearing subcutaneous PC3-PIP and PC3-FLU PCa tumors were injected intravenously with the HBP-peptide conjugate and assessed by fluorescence imaging. Enhanced accumulation in the tumor tissue of PC3-PIP compared to PC3-FLU highlighted the applicability of this system as a future imaging and therapeutic delivery vehicle.
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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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Raman spectra were recorded in the range 400–1800 cm−1 for a series of 15 mixed \[tetrakis(4-tert-butylphenyl)porphyrinato](2,3-naphthalocyaninato) rare earth double-deckers M(TBPP)(Nc) (M = Y; La–Lu except Pm) using laser excitation at 632.8 and 785 nm. Comparisons with bis(naphthalocyaninato) rare earth counterparts reveal that the vibrations of the metallonaphthalocyanine M(Nc) fragment dominate the Raman features of M(TBPP)(Nc). When excited with radiation of 632.8 nm, the most intense vibration appears at about 1595 cm−1, due to the naphthalene stretching. These complexes exhibit the marker Raman band for Nc•− as a medium-intense band in the range 1496–1507 cm−1, attributed to the coupling of pyrrole and aza stretching, while the marker Raman band of Nc2− in intermediate-valence Ce(TBPP)(Nc) appears as a strong band at 1493 cm−1 and is due to the isoindole stretchings. By contrast, when excited with radiation of 785 nm that is in close resonance with the main Q absorption band of the naphthalocyanine ligand, the ring radial vibrations at ca 680 and 735 cm−1 for MIII(TBPP)(Nc) are selectively intensified and are the most intense bands. For the cerium double-decker, the most intense vibration also acting as the marker Raman band of Nc2− appears at 1497 cm−1 with contributions from both pyrrole CC and aza CN stretches. The same vibrational modes show weak to medium intensity scattering at 1506–1509 cm−1 for MIII(TBPP)(Nc) and this is the marker Raman band of Nc•− when thus excited. The scatterings due to the Nc breathings, ring radial vibration, aza group stretchings, naphthalene stretchings, benzoisoindole stretchings and the coupling of pyrrole CC and aza CN stretchings in MIII(TBPP)(Nc) are all slightly blue shifted along with the decrease in rare earth ionic radius, confirming the effects of increased ring–ring interactions on the Raman characteristics of naphthalocyanine in the mixed ring double-deckers.
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Schools in Queensland, Australia, are undergoing inclusive education reform, following the report of the Ministerial Taskforce on Inclusive Education (Students with Disabilities) in 2004. The State government’s responses to the taskforce report emphasise a commitment to social justice and equity so that all students can be included in ways that enable them to achieve their potential. Teacher aides are employed in schools as ancillary staff to support students with disabilities and learning difficulties. Their support roles in schools are emerging within an educational context in which assumptions about disability, difference and inclusion of students with disabilities and learning difficulties are changing. It is important to acknowledge teacher aides as support practitioners, and to understand their roles in relation to the inclusion of students with disabilities and learning difficulties as inclusive education reform continues. This study used a phenomenological approach to explore the lived experiences of teacher aides as they supported students with disabilities and learning difficulties in primary schools. Four key insights into the support roles of teacher aides in primary schools in Brisbane, Queensland emerged from the study: 1) teacher aides develop empathetic relationships with students that contribute significantly to the students’ sense of belonging within school communities; 2) lack of clear definition of roles and responsibilities for teacher aides has detrimental effects on inclusion of students; 3) collaborative planning and implementation of classroom learning and socialisation programs enhances inclusion; and 4) teacher aides learn about supporting students while on-the-job, and in consultation and collaboration with other members of the students’ support networks.
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Debates concerning the veracity, ethics and politics of the documentary form circle endlessly around the function of those who participate in it, and the meaning attributed to their participation. Great significance is attached to the way that documentary filmmakers do or do not participate in the world they seek to represent, just as great significance is attached to those subjects whose participation extends beyond playing the part of eyewitness or expert, such that they become part of the very filmmaking process itself. This Ph.D. explores the interface between documentary practice and participatory culture by looking at how their practices, discursive fields and histories intersect, but also by looking at how participating in one might mean participating in the other. In short, the research is an examination of participatory culture through the lens of documentary practice and documentary criticism. In the process, however, this examination of participatory culture will in turn shed light on documentary thinking, especially the meaning and function of ‘the participant’ in contemporary documentary practice. A number of ways of conceiving of participation in documentary practice are discussed in this research, but one of the ideas that gives purpose to that investigation is the notion that the participant in contemporary documentary practice is someone who belongs to a participatory culture in particular. Not only does this mean that those subjects who play a part in a documentary are already informed by their engagement with a range of everyday media practices before the documentary apparatus arrives, the audience for such films are similarly informed and engaged. This audience have their own expectations about how they should be addressed by media producers in general, a fact that feeds back into their expectations about participatory approaches to documentary practice too. It is the ambition of this research to get closer to understanding the relationship between participants in the audience, in documentary and ancillary media texts, as well as behind the camera, and to think about how these relationships constitute a context for the production and reception of documentary films, but also how this context might provide a model for thinking about participatory culture itself. One way that documentary practice and participatory culture converge in this research is in the kind of participatory documentary that I call the ‘Camera Movie’, a narrow mode of documentary filmmaking that appeals directly to contemporary audiences’ desires for innovation and participation, something that is achieved in this case by giving documentary subjects control of the camera. If there is a certain inevitability about this research having to contend with the notion of the ‘participatory documentary’, the ‘participatory camera’ also emerges strongly in this context, especially as a conduit between producer and consumer. Making up the creative component of this research are two documentaries about the reality television event Band In A Bubble, and participatory media practices more broadly. The single-screen film, Hubbub , gives form to the collective intelligence and polyphonous voice of contemporary audiences who must be addressed and solicited in increasingly innovative ways. One More Like That is a split-screen, DVD-Video with alternate audio channels selected by a user who thereby chooses who listens and who speaks in the ongoing conversation between media producers and media consumers. It should be clear from the description above that my own practice does not extend to highly interactive, multi-authored or web-enabled practices, nor the distributed practices one might associate with social media and online collaboration. Mine is fundamentally a single authored, documentary video practice that seeks to analyse and represent participatory culture on screen, and for this reason the Ph.D. refrains from a sustained discussion of the kinds of collaborative practices listed above. This is not to say that such practices don’t also represent an important intersection of documentary practice and participatory culture, they simply represent a different point of intersection. Being practice-led, this research takes its procedural cues from the nature of the practice itself, and sketches parameters that are most enabling of the idea that the practice sets the terms of its own investigation.
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A surface plasmon resonance-based solution affinity assay is described for measuring the Kd of binding of heparin/heparan sulfate-binding proteins with a variety of ligands. The assay involves the passage of a pre-equilibrated solution of protein and ligand over a sensor chip onto which heparin has been immobilised. Heparin sensor chips prepared by four different methods, including biotin–streptavidin affinity capture and direct covalent attachment to the chip surface, were successfully used in the assay and gave similar Kd values. The assay is applicable to a wide variety of heparin/HS-binding proteins of diverse structure and function (e.g., FGF-1, FGF-2, VEGF, IL-8, MCP-2, ATIII, PF4) and to ligands of varying molecular weight and degree of sulfation (e.g., heparin, PI-88, sucrose octasulfate, naphthalene trisulfonate) and is thus well suited for the rapid screening of ligands in drug discovery applications.
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Purpose: In the present work we consider our (in progress) spectroscopy study of zinc and iron phosphates under the influence external high pressure to determine zinc ion change coordination from tetrahedral to octahedral (or hexahedral) structure.----- Design/methodology/approach: The standard equipment is the optical high pressure cell with diamond (DAC). The DAC is assembled and then vibrational or electronic spectra are collected by mounting the cell in an infrared, Raman, EXAFS or UV-visible spectrometer.----- Findings: Mechanism by which zinc and iron methaphosphate material is transformed to glassy meta-phosphate is enhancing mechanical properties of tribofilm. The two decades of intensive study demonstrates that Zn (II) and Fe (III) ions participate to cross-link network under friction, hardening the phosphate.----- Research limitations/implications: Transition metal atoms with d orbital have flexible coordination numbers, for example zinc acts as a cross-linking agent increasing hardness, by changing coordination from tetrahedral to octahedral. Perhaps the external pressure effect on the [Zn–(O-P-)4 ] complex causes a transformation to an [Zn –(O-P-)6] grouping.----- Originality/value: This paper analyses high-pressure spectroscopy which has been applied for the investigation of 3D transition metal ions in solids. When studying pressure effects on coordination compounds structure, we can expect changes in ground electronic state (spin-crossovers), electronic spectra due to structural distortions (piezochromism), and changes in the ligand field causing shifts in the electronic transitions.