588 research outputs found

    Effect of intraligand π-delocalization on the photophysical properties of two new Ru(II) complexes

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    Two new Ru(II) complexes, [Ru(bpy)2(1-COO-iqu)]+ (2; bpy = 2,2_-bipyridine, 1-COO-iqu− = isoquinoline- 1-carboxylate) and [Ru(bpy)2(3-COO-iqu)]+ (3; 3-COO-iqu− = isoquinoline-3-carboxylate), were prepared and their crystal structures solved. The ground and excited state properties of 2 and 3 were characterized and compared to those of [Ru(bpy)3]2+ (1). The presence of the oxygen atom in the Ru(II) coordination sphere makes 2 and 3 easier to oxidize than 1. The Ru→bpy MLCT absorption and emission of 2 and 3 are red-shifted relative to that of 1 in CH2Cl2, and the E00 energies were estimated to be 1.89 eV and 1.95 eV from the low temperature emission of 2 and 3, resulting in excited state oxidation potentials of −1.03V and −1.10V vs SCE, respectively. In addition to the short-lived emissive 3MLCT state, a longlived species is observed in the transient absorption of 3 in DMSO (Ƭ=49μs) and pyridine (Ƭ =44μs), assigned to a solvent-coordinated complex. This intermediate is not observed for 3 in non-polar solvents or for 2. The absence of the solvent coordinated intermediate in 2 is explained by the stronger Ru–O bond afforded by the lower conjugation in that extends onto the carboxylic acid in the 1-COO-iquo−ligand, compared to that in the 3-COO-iqu−ligand in 3. Transient absorption experiments also show that the 3MLCT excited state of 3 is able to reduce methyl viologen

    Tris(3-nitro­pentane-2,4-dionato-κ2 O,O′)­cobalt(III)

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    The structure of the title compound, [Co(C5H6NO4)3], consists of a CoIII ion octahedrally coordinated by three bidentate 3-nitro­pentane-2,4-dionate ligands. The complex was prepared via the nitration of tris­(2,4-penta­nedionato-κ2 O,O′)cobalt(III) with a solution of copper(II) nitrate in glacial acetic acid. The central C atom and the nitro group of one 3-nitro­pentane-2,4-dionate ligand are disordered over two positions with an occupancy ratio of 0.848 (4):0.152 (4). A second nitro group is also disordered over two orientations with an occupancy ratio of 0.892 (7):0.108 (7). Two of the ligand methyl groups form C—H⋯O inter­actions with two different nitro groups to form chains running along the c axis. Additional C—H⋯O inter­actions are found between ligand methyl groups and the cobalt-bound O atoms, also resulting in the formation of chains along the c axis

    A low-temperature phase of bis(tetrabutylammonium) octa-l3-chloridohexachlorido- octahedro-hexatungstate

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    The article discusses the low-temperature phase of bis(tetrabutylammonium) octa-µ3-chlorido-hexachlorido-octahedro-hexa-tungstate, which undergoes a reversible phase transition at 268 K. The unit cells of the room- and low-temperature polymorphs of this compound are found to be closely related. The hydrocarbon chain of one of the tetrabutylammonium cations is found to be disordered at both 150 and 200 K

    Healthy country, healthy people: the relationship between Indigenous health status and "caring for country"

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    Objective: To investigate associations between “caring for country” — an activity that Indigenous peoples assert promotes good health — and health outcomes relevant to excess Indigenous morbidity and mortality.Design, setting and participants: Cross-sectional study involving 298 Indigenous adults aged 15–54 years in an Arnhem Land community, recruited from March to September 2005.Main outcome measures: Self-reported involvement in caring for country, health behaviours and clinically measured body mass index (BMI), waist circumference, blood pressure, type 2 diabetes status, albumin to creatinine ratio (ACR), levels of glycated haemoglobin (HbA1c) and high-density lipoprotein (HDL) cholesterol, lipid ratio, score on the five-item version of the Kessler Psychological Distress Scale (K5), and 5-year cardiovascular disease (CVD) risk.Results: Controlling for sociodemographic characteristics and health behaviours, multivariate regression revealed significant and substantial associations between caring for country and health outcomes. An interquartile range rise in the weighted composite caring-for-country score was significantly associated with more frequent physical activity, better diet, lower BMI (regression coefficient [b] = − 2.83; 95% CI, − 4.56 to − 1.10), less abdominal obesity (odds ratio [OR], 0.43; 95% CI, 0.26–0.72), lower systolic blood pressure (b = − 7.59; 95% CI, − 12.01 to − 3.17), less diabetes (OR, 0.12; 95% CI, 0.03–0.52), lower HbA1c level (b = − 0.45; 95% CI, − 0.79 to − 0.11), non-elevated ACR (OR, 0.28; 95% CI, 0.13–0.60), higher HDL cholesterol level (b = 0.06; 95% CI, 0.01–0.12), lower K5 score (b = − 0.97; 95% CI, − 1.64 to − 0.31) and lower CVD risk (b = − 0.77; 95% CI, − 1.43 to − 0.11).Conclusions: Greater Indigenous participation in caring for country activities is associated with significantly better health. Although the causal direction of these associations requires clarification, our findings suggest that investment in caring for country may be a means to foster sustainable economic development and gains for both ecological and Indigenous peoples’ health

    2,5-Dimethyl-1,3-dinitro­benzene

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    The title compound, C8H8N2O4, was prepared via the nitration of p-xylene. The mol­ecules are stacked along the c axis in an antiparallel manner. The two nitro groups are rotated relative to the benzene ring with dihedral angles of 44.50 (7) and 31.67 (8)°. The tilt of the nitro groups allows the formation of C—H⋯O inter­actions between the ring C—H and nitro groups of adjacent mol­ecules creating puckered sheets perpendicular to the c axis. The H atoms of the methyl group in the 5-position are disordered (60° rotation) with an occupancy of 0.616 (19) for the major component. The crystal was found to be a non-merohedral twin with a twin law [−1 −0.002 0.005, 0.00031 −1 0.002, 0.118 −0.007 1] corresponding to a rotation of 180° about the reciprocal axis (001) and refined to give a minor component fraction of 0.320 (2)

    TB STIGMA – MEASUREMENT GUIDANCE

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    TB is the most deadly infectious disease in the world, and stigma continues to play a significant role in worsening the epidemic. Stigma and discrimination not only stop people from seeking care but also make it more difficult for those on treatment to continue, both of which make the disease more difficult to treat in the long-term and mean those infected are more likely to transmit the disease to those around them. TB Stigma – Measurement Guidance is a manual to help generate enough information about stigma issues to design and monitor and evaluate efforts to reduce TB stigma. It can help in planning TB stigma baseline measurements and monitoring trends to capture the outcomes of TB stigma reduction efforts. This manual is designed for health workers, professional or management staff, people who advocate for those with TB, and all who need to understand and respond to TB stigma

    Pannexin 1 binds β-catenin to modulate melanoma cell growth and metabolism

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    Melanoma is the most aggressive skin malignancy with increasing incidence worldwide. Pannexin1 (PANX1), a member of the pannexin family of channel-forming glycoproteins, regulates cellular processes in melanoma cells including proliferation, migration, and invasion/metastasis. However, the mechanisms responsible for coordinating and regulating PANX1 function remain unclear. Here, we demonstrated a direct interaction between the C-terminal region of PANX1 and the N-terminal portion of β-catenin, a key transcription factor in the Wnt pathway. At the protein level, β-catenin was significantly decreased when PANX1 was either knocked down or inhibited by two PANX1 blockers, Probenecid and Spironolactone. Immunofluorescence imaging showed a disrupted pattern of β-catenin localization at the cell membrane in PANX1-deficient cells, and transcription of several Wnt target genes, including MITF, was suppressed. In addition, a mitochondrial stress test revealed that the metabolism of PANX1-deficient cells was impaired, indicating a role for PANX1 in the regulation of the melanoma cell metabolic profile. Taken together, our data show that PANX1 directly interacts with β-catenin to modulate growth and metabolism in melanoma cells. These findings provide mechanistic insight into PANX1-mediated melanoma progression and may be applicable to other contexts where PANX1 and β-catenin interact as a potential new component of the Wnt signaling pathway

    Creating the collective: social media, the Occupy Movement and its constitution as a collective actor

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    This paper examines the process through which Occupy activists came to constitute themselves as a collective actor and the role of social media in this process. The theoretical framework combines Melucci's (1996) theory of collective identity with insights from the field of organizational communication and particularly from the ‘CCO’ strand – short for ‘Communication is Constitutive of Organizing’. This allows us to conceptualize collective identity as an open-ended and dynamic process that is constructed in conversations and codified in texts. Based on interviews with Occupy activists in New York, London and other cities, I then discuss the communication processes through which the movement was drawing the boundaries with its environment, creating codes and foundational documents, as well as speaking in a collective voice. The findings show that social media tended to blur the boundaries between the inside and the outside of the movement in a way that suited its values of inclusiveness and direct participation. Social media users could also follow remotely the meetings of the general assembly where the foundational documents were ratified, but their voices were not included in the process. The presence of the movement on social media also led to conflicts and negotiations around Occupy's collective voice as constructed on these platforms. Thus, viewing the movement as a phenomenon emerging in communication allows us an insight into the efforts of Occupy activists to create a collective that was both inclusive of the 99% and a distinctive actor with its own identity

    Influence of apical oxygen on the extent of in-plane exchange interaction in cuprate superconductors

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    In high Tc superconductors the magnetic and electronic properties are determined by the probability that valence electrons virtually jump from site to site in the CuO2 planes, a mechanism opposed by on-site Coulomb repulsion and favored by hopping integrals. The spatial extent of the latter is related to transport properties, including superconductivity, and to the dispersion relation of spin excitations (magnons). Here, for three antiferromagnetic parent compounds (single-layer Bi2Sr0.99La1.1CuO6+delta, double-layer Nd1.2Ba1.8Cu3O6 and infinite-layer CaCuO2) differing by the number of apical atoms, we compare the magnetic spectra measured by resonant inelastic x-ray scattering over a significant portion of the reciprocal space and with unprecedented accuracy. We observe that the absence of apical oxygens increases the in-plane hopping range and, in CaCuO2, it leads to a genuine 3D exchange-bond network. These results establish a corresponding relation between the exchange interactions and the crystal structure, and provide fresh insight into the materials dependence of the superconducting transition temperature.Comment: 9 pages, 4 figures, 1 Table, 42 reference

    Indentation Plastometry of Welds

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    This investigation concerns the application of the profilometry‐based indentation plastometry (PIP) methodology to obtain stress–strain relationships for material in the vicinity of fusion welds. These are produced by The Welding Institute (TWI), using submerged arc welding to join pairs of thick steel plates. The width of the welds varies from about 5 mm at the bottom to about 40–50 mm at the top. For one weld, the properties of parent and weld metal are similar, while for the other, the weld metal is significantly harder than the parent. Both weldments are shown to be approximately isotropic in terms of mechanical response, while there is a small degree of anisotropy in the parent metal (with the through‐thickness direction being slightly softer than the in‐plane directions). The PIP procedure has a high sensitivity for detecting such anisotropy. It is also shown that there is excellent agreement between stress–strain curves obtained using PIP and via conventional uniaxial testing (tensile and compressive). Finally, the PIP methodology is used to explore properties in the transition regime between weld and parent, with a lateral resolution of the order of 1–2 mm. This reveals variations on a scale that would be very difficult to examine using conventional testing
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