345 research outputs found

    A nitrogen-gas-stream cryostat for general X-ray diffraction studies

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    Examining the Variability in General Education Placements for Students With Intellectual Disability

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    Despite the overwhelming body of research suggesting that students with intellectual disability benefit from access to general education placements, students with intellectual disability continue to be educated primarily in segregated settings. Furthermore, the percentage of students with intellectual disability included in general education classrooms varies greatly among and within states across the United States. In an effort to explore such variability in New York State, we examined trends in general education placement rates of students with intellectual disability across districts and possible predictors of placement in regular classes. Results suggest that although descriptive patterns of placement exist, a more definitive explanation of variability requires a deeper analysis of policy and procedure at the district level

    Hypoxia Sensitive Metal β-Ketoiminate Complexes Showing Induced Single Strand DNA Breaks and Cancer Cell Death by Apoptosis

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    A series of ruthenium and iridium complexes have been synthesised and characterised with 20 novel crystal structures discussed. The library of β-ketoiminate complexes has been shown to be active against MCF-7 (human breast carcino-ma), HT-29 (human colon carcinoma), A2780 (human ovarian carcinoma) and A2780cis (cisplatin resistant human ovarian carcinoma) cell lines, with selected complexes being more than three times as active as cisplatin against the A2780cis cell line. Complexes have also been shown to be highly active under hypoxic conditions, with the activities of some complexes increasing with a decrease in O2 concentration. The enzyme thioredoxin reductase is over-expressed in cancer cells and complexes reported herein have the advantage of inhibiting this enzyme, with IC50 values measured in the nanomolar range. The anti-cancer activity of these complexes was further investigated to determine whether activity is due to effects on cellular growth or cell survival. The complexes were found to induce significant cancer cell death by apoptosis with levels induced correlating closely with activity in chemosensitivity studies. As a possible cause of cell death, the ability of the complexes to induce damage to cellular DNA was also assessed. The complexes failed to induce double strand DNA break or DNA crosslinking but induced significant levels of single DNA strand breaks indi-cating a different mechanism of action to cisplatin

    Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

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    Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

    Ferroelastic phases and order parameter treatment in Pb 3

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    Rh-POP Pincer Xantphos Complexes for C-S and C-H Activation. Implications for Carbothiolation Catalysis

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    The neutral Rh­(I)–Xantphos complex [Rh­(κ<sup>3</sup>-<sub>P,O,P</sub>-Xantphos)­Cl]<sub><i>n</i></sub>, <b>4</b>, and cationic Rh­(III) [Rh­(κ<sup>3</sup>-<sub>P,O,P</sub>-Xantphos)­(H)<sub>2</sub>]­[BAr<sup>F</sup><sub>4</sub>], <b>2a</b>, and [Rh­(κ<sup>3</sup>-<sub>P,O,P</sub>-Xantphos-3,5-C<sub>6</sub>H<sub>3</sub>(CF<sub>3</sub>)<sub>2</sub>)­(H)<sub>2</sub>]­[BAr<sup>F</sup><sub>4</sub>], <b>2b</b>, are described [Ar<sup>F</sup> = 3,5-(CF<sub>3</sub>)<sub>2</sub>C<sub>6</sub>H<sub>3</sub>; Xantphos = 4,5-bis­(diphenylphosphino)-9,9-dimethylxanthene; Xantphos-3,5-C<sub>6</sub>H<sub>3</sub>(CF<sub>3</sub>)<sub>2</sub> = 9,9-dimethylxanthene-4,5-bis­(bis­(3,5-bis­(trifluoromethyl)­phenyl)­phosphine]. A solid-state structure of <b>2b</b> isolated from C<sub>6</sub>H<sub>5</sub>Cl solution shows a κ<sup>1</sup>-chlorobenzene adduct, [Rh­(κ<sup>3</sup>-<sub>P,O,P</sub>-Xantphos-3,5-C<sub>6</sub>H<sub>3</sub>(CF<sub>3</sub>)<sub>2</sub>)­(H)<sub>2</sub>(κ<sup>1</sup>-ClC<sub>6</sub>H<sub>5</sub>)]­[BAr<sup>F</sup><sub>4</sub>], <b>3</b>. Addition of H<sub>2</sub> to <b>4</b> affords, crystallographically characterized, [Rh­(κ<sup>3</sup>-<sub>P,O,P</sub>-Xantphos)­(H)<sub>2</sub>Cl], <b>5</b>. Addition of diphenyl acetylene to <b>2a</b> results in the formation of the C–H activated metallacyclopentadiene [Rh­(κ<sup>3</sup>-<sub>P,O,P</sub>-Xantphos)­(ClCH<sub>2</sub>Cl)­(σ,σ-(C<sub>6</sub>H<sub>4</sub>)­C­(H)CPh)]­[BAr<sup>F</sup><sub>4</sub>], <b>7</b>, a rare example of a crystallographically characterized Rh–dichloromethane complex, alongside the Rh­(I) complex <i>mer</i>-[Rh­(κ<sup>3</sup>-<sub>P,O,P</sub>-Xantphos)­(η<sup>2</sup>-PhCCPh)]­[BAr<sup>F</sup><sub>4</sub>], <b>6</b>. Halide abstraction from [Rh­(κ<sup>3</sup>-<sub>P,O,P</sub>-Xantphos)­Cl]<sub><i>n</i></sub> in the presence of diphenylacetylene affords <b>6</b> as the only product, which in the solid state shows that the alkyne binds perpendicular to the κ<sup>3</sup>-POP Xantphos ligand plane. This complex acts as a latent source of the [Rh­(κ<sup>3</sup>-<sub>P,O,P</sub>-Xantphos)]<sup>+</sup> fragment and facilitates <i>ortho</i>-directed C–S activation in a number of 2-arylsulfides to give <i>mer</i>-[Rh­(κ<sup>3</sup>-<sub>P,O,P</sub>-Xantphos)­(σ,κ<sup>1</sup>-Ar)­(SMe)]­[BAr<sup>F</sup><sub>4</sub>] (Ar = C<sub>6</sub>H<sub>4</sub>COMe, <b>8</b>; C<sub>6</sub>H<sub>4</sub>(CO)­OMe, <b>9</b>; C<sub>6</sub>H<sub>4</sub>NO<sub>2</sub>, <b>10</b>; C<sub>6</sub>H<sub>4</sub>CNCH<sub>2</sub>CH<sub>2</sub>O, <b>11</b>; C<sub>6</sub>H<sub>4</sub>C<sub>5</sub>H<sub>4</sub>N, <b>12</b>). Similar C–S bond cleavage is observed with allyl sulfide, to give <i>fac</i>-[Rh­(κ<sup>3</sup>-<sub>P,O,P</sub>-Xantphos)­(η<sup>3</sup>-C<sub>3</sub>H<sub>5</sub>)­(SPh)]­[BAr<sup>F</sup><sub>4</sub>], <b>13</b>. These products of C–S activation have been crystallographically characterized. For <b>8</b> in situ monitoring of the reaction by NMR spectroscopy reveals the initial formation of <i>fac</i>-κ<sup>3</sup>-<b>8</b>, which then proceeds to isomerize to the <i>mer</i>-isomer. With the <i>para</i>-ketone aryl sulfide, 4-SMeC <sub>6</sub>H<sub>4</sub>COMe, C–H activation <i>ortho</i> to the ketone occurs to give <i>mer</i>-[Rh­(κ<sup>3</sup>-<sub>P,O,P</sub>-Xantphos)­(σ,κ<sup>1</sup>-4-(COMe)­C<sub>6</sub>H<sub>3</sub>SMe)­(H)]­[BAr<sup>F</sup><sub>4</sub>], <b>14</b>. The temporal evolution of carbothiolation catalysis using <i>mer</i>-κ<sup>3</sup>-<b>8</b>, and phenyl acetylene and 2-(methylthio)­acetophenone substrates shows initial fast catalysis and then a considerably slower evolution of the product. We suggest that the initially formed <i>fac</i>-isomer of the C–S activation product is considerably more active than the <i>mer</i>-isomer (i.e., <i>mer</i>-<b>8</b>), the latter of which is formed rapidly by isomerization, and this accounts for the observed difference in rates. A likely mechanism is proposed based upon these data

    2-(4-Fluoro­phen­yl)-2-oxoethyl 4-meth­oxy­benzoate

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    In the title compound, C16H13FO4, the dihedral angle between the benzene rings is 84.28 (8)°. In the crystal, C—H⋯F and C—H⋯O hydrogen bonds link the mol­ecules to form a three-dimensional network. The crystal structure is consolidated by C—H⋯π inter­actions and short F⋯F contacts [2.7748 (14) Å] also occur

    Diethyl 4-[2-(4-meth­oxy­phen­yl)-1H-pyrazol-3-yl]-2,6-dimethyl-1,4-dihydro­pyridine-3,5-dicarboxyl­ate

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    In the title compound, C23H27N3O5, the pyrazole ring is inclined at dihedral angles of 38.16 (6) and 80.80 (6)°, respectively, to the least-squares planes of the benzene and dihydro­pyridine rings. In the crystal, adjacent mol­ecules are linked via a pair of N—H⋯N hydrogen bonds, forming an inversion dimer. The dimers are stacked in a column along the a axis through N—H⋯O hydrogen bonds. Intra- and inter­molecular C—H⋯N and C—H⋯O hydrogen bonds are also observed

    Ferrocene-1-carbaldehyde thio­semi­carbazone

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    The asymmetric unit of the title compound, [Fe(C5H5)(C7H8N3S)], consists of two crystallographically independent mol­ecules, A and B. The cyclo­penta­dienyl (Cp) rings in both mol­ecules adopt an eclipsed conformation and are parallel to each other, forming dihedral angles of 2.5 (3) and 1.1 (3)°, respectively. The mean plane of the semicarbazone group is coplanar with the attached Cp ring in mol­ecule A, whereas it is twisted away in mol­ecule B. In the crystal structure, inter­molecular N—H⋯S hydrogen bonds link the mol­ecules into two-dimensional planes parallel to the ab plane. The structure is further consolidated by C—H⋯π inter­actions
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