84 research outputs found
Philip Power at 65:An icon of organometallic chemistry
We are delighted to present this collection of articles to celebrate the work of Philip Power on the occasion of his 65th birthday.</p
Selective reduction of CO<sub>2</sub> to a methanol equivalent by B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>-activated alkaline earth catalysis
Treatment of β-diketiminato Mg and Ca amidoborane compounds with B(C6F5)3 induces hydride elimination and formation of alkaline earth hydrido-tris(pentafluorophenyl)borate derivatives. Both species react with CO2 to provide formate complexes, one of which has been structurally characterised, and may be applied to the highly selective reductive hydroboration of CO2 with pinacolborane (HBpin) to provide the methanol equivalent, CH3OBpin
'Surf's up!':A call to take english soccer fan interactions on the internet more seriously
Soccer fandom practices in England have been significantly impacted by globalization. The creation of the Premier League in 1992, and the way in which satellite television company BSkyB dominated coverage of this, together with other developments, have led to changes in how fans consume top-level English soccer. Whilst such global transformations are well documented in the sociology of soccer literature, the implications of the rise of the most advanced global form of communication - the Internet - on the practices of fans of English soccer clubs, have not been fully taken into account by academics. As such, the significance of the Internet as a site for fans to interact remains under-investigated. This article argues that online interactions between fans of English clubs need to be taken more seriously by academics if they are to more fully understand how soccer contributes to the maintenance of social identities in contemporary England
Gluten Induces Subtle Histological Changes in Duodenal Mu-cosa of Patients with Non-Coeliac Gluten Sensitivity: A Multi-center Study
Histological changes induced by gluten in the duodenal mucosa of patients with non-coeliac gluten sensitivity (NCGS) are poorly defined. Objectives: To evaluate the structural and inflammatory features of NCGS compared to controls and coeliac disease (CeD) with milder enteropathy (Marsh I-II). Methods: Well-oriented biopsies of 262 control cases with normal gastroscopy and histologic findings, 261 CeD, and 175 NCGS biopsies from 9 contributing countries were examined. Villus height (VH, in μm), crypt depth (CrD, in μm), villus-to-crypt ratios (VCR), IELs (intraepithelial lymphocytes/100 enterocytes), and other relevant histological, serologic, and demographic parameters were quantified. Results: The median VH in NCGS was significantly shorter (600, IQR: 400−705) than controls (900, IQR: 667−1112) (p < 0.001). NCGS patients with Marsh I-II had similar VH and VCR to CeD [465 µm (IQR: 390−620) vs. 427 µm (IQR: 348−569, p = 0·176)]. The VCR in NCGS with Marsh 0 was lower than controls (p < 0.001). The median IEL in NCGS with Marsh 0 was higher than controls (23.0 vs. 13.7, p < 0.001). To distinguish Marsh 0 NCGS from controls, an IEL cut-off of 14 showed 79% sensitivity and 55% specificity. IEL densities in Marsh I-II NCGS and CeD groups were similar. Conclusion: NCGS duodenal mucosa exhibits distinctive changes consistent with an intestinal response to luminal antigens, even at the Marsh 0 stage of villus architecture
In vivo study of experimental pneumococcal meningitis using magnetic resonance imaging
<p>Abstract</p> <p>Background</p> <p>Magnetic Resonance Imaging (MRI) methods were evaluated as a tool for the study of experimental meningitis. The identification and characterisation of pathophysiological parameters that vary during the course of the disease could be used as markers for future studies of new treatment strategies.</p> <p>Methods</p> <p>Rats infected intracisternally with <it>S. pneumoniae </it>(n = 29) or saline (n = 13) were randomized for imaging at 6, 12, 24, 30, 36, 42 or 48 hours after infection. T1W, T2W, quantitative diffusion, and post contrast T1W images were acquired at 4.7 T. Dynamic MRI (dMRI) was used to evaluate blood-brain-barrier (BBB) permeability and to obtain a measure of cerebral and muscle perfusion. Clinical- and motor scores, bacterial counts in CSF and blood, and WBC counts in CSF were measured.</p> <p>Results</p> <p>MR images and dMRI revealed the development of a highly significant increase in BBB permeability (P < 0.002) and ventricle size (P < 0.0001) among infected rats. Clinical disease severity was closely related to ventricle expansion (P = 0.024).</p> <p>Changes in brain water distribution, assessed by ADC, and categorization of brain 'perfusion' by cortex ΔSI<sub>(bolus) </sub>were subject to increased inter-rat variation as the disease progressed, but without overall differences compared to uninfected rats (P > 0.05). Areas of well-'perfused' muscle decreased with the progression of infection indicative of septicaemia (P = 0.05).</p> <p>Conclusion</p> <p>The evolution of bacterial meningitis was successfully followed <it>in-vivo </it>with MRI. Increasing BBB-breakdown and ventricle size was observed in rats with meningitis whereas changes in brain water distribution were heterogeneous. MRI will be a valuable technique for future studies aiming at evaluating or optimizing adjunctive treatments</p
Mechanisms of the Thermal and Catalytic Redistributions, Oligomerizations, and Polymerizations of Linear Diborazanes
Activation of N-heterocyclic carbenes by {BeH<sub>2</sub>} and {Be(H)(Me)} fragments
A stable three-coordinate dimethylberyllium
species coordinated
by the 1,3-bisÂ(2,4,6-trimethylphenyl)Âimidazol-2-ylidene (IMes) ligand
is readily converted to the corresponding methylhydrido derivative
through metathetical reaction with phenylsilane. Attempts to synthesize
the corresponding molecular dihydrides are, however, unsuccessful
and result in ring opening of an IMes ligand through hydride transfer
to the donor carbon atom and the consequent formation of a heterocyclic
beryllium organoamide. In agreement with previous calculations, we
suggest that this process occurs via a Schlenk-type equilibration
process and formation of a four-coordinate bis-NHC beryllium dihydride.
These species are not observed, however, as the steric pressure exerted
by coordination of the two sterically demanding IMes ligands is sufficient
to induce hydride transfer. The latter deduction is supported by the
observation that a similar ring-opened product, but derived from methyl
and hydride transfer, is available through the introduction of a further
equivalent of IMes to the isolated beryllium methyl hydride species.
In the latter case the ring-opening process is more facile, which
we ascribe to the increased steric pressure achieved upon the formation
of four-coordinate beryllium. In a further striking reaction under
more forcing thermal conditions, the carbene carbon center of an IMes
ligand is observed to be completely eliminated with selective formation
of a three-coordinate diamidoberyllium species
Philip Power at 65:An icon of organometallic chemistry
Professor Philip P. Power turns 65 in 2018. His contributions to organometallic and inorganic chemistry over the last four decades are expansive, and he has been instrumental in the definition of several new subfields in the discipline. Professor Power has contributed over 500 publications to the literature. His lab remains an active source of exciting chemistry and has been a way point in numerous successful chemists’ careers. A focus on low-coordinate, low-valent and low-oxidation state compounds defines Power's career and molecules in this class generally feature a small energy difference between frontier orbitals.</p
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