48 research outputs found
Synthesis and Reactivity of Iridium(III) Dihydrido Aminocarbenes
Iridium complexes supported by the PNP amidophosphine scaffold (PNP = [N(2-PiPr2-4-Me-C6H3)2]â) perform the selective double CâH activation of methyl amines to produce iridium(III) dihydrido aminocarbenes. The reactivity of these complexes is presented and contrasted with that observed for the previously reported iridium(I) alkoxycarbenes
Regulation of plasmid-encoded isoprene metabolism in Rhodococcus, a representative of an important link in the global isoprene cycle
Emissions of biogenic volatile organic compounds (VOCs) form an important part of the global carbon cycle, comprising a significant proportion of net ecosystem productivity. They impact atmospheric chemistry and contribute directly and indirectly to greenhouse gases. Isoprene, emitted largely from plants, comprises one third of total VOCs, yet in contrast to methane, which is released in similar quantities, we know little of its biodegradation. Here, we report the genome of an isoprene degrading isolate, Rhodococcus sp. AD45, and, using mutagenesis shows that a plasmid-encoded soluble di-iron centre isoprene monooxygenase (IsoMO) is essential for isoprene metabolism. Using RNA sequencing (RNAseq) to analyse cells exposed to isoprene or epoxyisoprene in a substrate-switch time-course experiment, we show that transcripts from 22 contiguous genes, including those encoding IsoMO, were highly upregulated, becoming among the most abundant in the cell and comprising over 25% of the entire transcriptome. Analysis of gene transcription in the wild type and an IsoMO-disrupted mutant strain showed that epoxyisoprene, or a subsequent product of isoprene metabolism, rather than isoprene itself, was the inducing molecule. We provide a foundation of molecular data for future research on the environmental biological consumption of this important, climate-active compound
trans-Acetyldicarbonyl(g5 -cyclopentadienyl)(methyldiphenylphosphane)- molybdenum(II)
The title compound, [Mo(C5H5)(C2H3O)(C13H13P)(CO)2], was prepared by reaction of [Mo(CH3)(C5H5)(CO)3] with methyldiphenylphosphane. The MoII atom exhibits a fourlegged piano-stool coordination geometry with the acetyl and phosphane ligands trans to each other. There are several intermolecular CâHO hydrogen-bonding interactions involving carbonyl and acetyl O atoms as acceptors. A close nearly parallel â interaction between the cyclopentadienyl plane and the phenyl ring of the phosphane ligand is present, with an angle of 6.4 (1) between the two least-squares planes. The centroid-to-centroid distance between these groups is 3.772 (3) AË , and the closest distance between two atoms of these groups is 3.449 (4) AË . Since each Mo complex is engaged in two of these interactions, the complexes form an infinite - stack coincident with the a axis
Gender Differences in Russian Colour Naming
In the present study we explored Russian colour naming in a web-based psycholinguistic experiment
(http://www.colournaming.com). Colour singletons representing the Munsell Color Solid (N=600 in total) were presented on a computer monitor and named using an unconstrained colour-naming method. Respondents were
Russian speakers (N=713). For gender-split equal-size samples (NF=333, NM=333) we estimated and compared (i)
location of centroids of 12 Russian basic colour terms (BCTs); (ii) the number of words in colour descriptors; (iii) occurrences of BCTs most frequent non-BCTs. We found a close correspondence between femalesâ and malesâ
BCT centroids. Among individual BCTs, the highest inter-gender agreement was for seryj âgreyâ and goluboj
âlight blueâ, while the lowest was for sinij âdark blueâ and krasnyj âredâ. Females revealed a significantly richer repertory of distinct colour descriptors, with great variety of monolexemic non-BCTs and âfancyâ colour names; in comparison, males offered relatively more BCTs or their compounds. Along with these measures, we gauged
denotata of most frequent CTs, reflected by linguistic segmentation of colour space, by employing a synthetic
observer trained by gender-specific responses. This psycholinguistic representation revealed femalesâ more
refined linguistic segmentation, compared to males, with higher linguistic density predominantly along the redgreen axis of colour space
Physiological characteristics of dysphagia following thermal burn injury
The study aim was to document the acute physiological characteristics of swallowing impairment following thermal burn injury. A series of 19 participants admitted to a specialised burn centre with thermal burn injury were identified with suspected aspiration risk by a clinical swallow examination (CSE) conducted by a speech-language pathologist and referred to the study. Once medically stable, each then underwent more detailed assessment using both a CSE and fiberoptic evaluation of swallowing (FEES). FEES confirmed six individuals (32%) had no aspiration risk and were excluded from further analyses. Of the remaining 13, CSE confirmed that two had specific oral-phase deficits due to orofacial scarring and contractures, and all 13 had generalised oromotor weakness. FEES revealed numerous pharyngeal-phase deficits, with the major findings evident in greater than 50% being impaired secretion management, laryngotracheal edema, delayed swallow initiation, impaired sensation, inadequate movement of structures within the hypopharynx and larynx, and diffuse pharyngeal residue. Penetration and/or aspiration occurred in 83% (n = 10/12) of thin fluids trials, with a lack of response to the penetration/aspiration noted in 50% (n = 6/12 penetration aspiration events) of the cases. Most events occurred post swallow. Findings support the fact that individuals with dysphagia post thermal burn present with multiple risk factors for aspiration that appear predominantly related to generalised weakness and inefficiency and further impacted by edema and sensory impairments. Generalised oromotor weakness and orofacial contractures (when present) impact oral-stage swallow function. This study has identified a range of factors that may contribute to both oral- and pharyngeal-stage dysfunction in this clinical population and has highlighted the importance of using a combination of clinical and instrumental assessments to fully understand the influence of burn injury on oral intake and swallowing
Chemical Annealing of Zinc Tetraphenylporphyrin Films: Effects on Film Morphology and Organic Photovoltaic Performance
We present a chemical annealing process for organic thin
films.
In this process, a thin film of a molecular material, such as zinc
tetraphenylporphyrin (ZnTPP), is exposed to a vapor of nitrogen-based
ligand (e.g., pyrazine, pz, and triazine, tz), forming a film composed
of the metalâligand complex. Fast and quantitative formation
of the complex leads to marked changes in the morphology and optical
properties of the film. X-ray diffraction studies show that the chemical
annealing process converts amorphous ZnTPP films to crystalline ZnTPP¡ligand
films, whose porphryin planes lie nearly parallel to the substrate
(average deviation is 8° for the ZnTPP¡pz film). Organic
solar cells were prepared with ZnTPP donor and C<sub>60</sub> acceptor
layers. Devices were prepared with and without chemical annealing
of the ZnTPP layer with a pyrazine ligand. The devices with chemically
annealed ZnTPP donor layer show an increase in short-circuit current
(<i>J</i><sub>SC</sub>) and fill factor (<i>FF</i>) relative to analogous unannealed devices, presumably because of
enhanced exciton diffusion length and improved charge conductivity.
The open circuit voltages (<i>V</i><sub>OC</sub>) of the
chemically annealed devices are lower than their unannealed counterpart
because of enhanced polaron pair recombination at the donor/acceptor
heterojunction. A net improvement of 5â20% in efficiency has
been achieved, after chemical annealing of ZnTPP films with pyrazine