48 research outputs found
tert-Butyl N-hydrÂoxy-N-[(1S*,2R*)-2-(1-naphthÂyl)cycloÂpent-3-en-1-yl]carbamate
The relative stereochemistry of the title compound, C20H23NO3, was established by X-ray analysis. The asymmetric unit contains two independent molÂecules. In the crystal structure, each type of molÂecule forms a centrosymmetric dimer via pairs of interÂmolecular OâHâŻO hydrogen bonds, resulting in an R
2
2(10) loop in each case
Formal [4 + 2] cycloaddition of alkoxy-substituted donor-acceptor cyclobutanes and aldehydes catalyzed by Yb(OTf)3.
The cycloaddition between 2-alkoxy-1,1-cyclobutane diesters and aromatic, heteroaromatic, or aliphatic aldehydes under Yb(OTf)(3) catalysis generates tetrahydropyrans in high yields with exclusive cis-stereochemistry
Increased yields and simplified purification with a second-generation cobalt catalyst for the oxidative formation of trans-THF rings.
The synthesis of a second-generation cobalt catalyst for the formation of trans-THF products via the Mukaiyama aerobic oxidative cyclization is reported. Two procedures have been developed with the new water-soluble catalyst that give superior yields and greatly simplify purification compared to the previous catalysts
Formal [4 + 2] Cycloaddition of Alkoxy-Substituted DonorâAcceptor Cyclobutanes and Aldehydes Catalyzed by Yb(OTf) 3
Reliability of a novel thermal imaging system for temperature assessment of healthy feet
Abstract Background Thermal imaging is a useful modality for identifying preulcerative lesions (âhot spotsâ) in diabetic foot patients. Despite its recognised potential, at present, there is no readily available instrument for routine podiatric assessment of patients at risk. To address this need, a novel thermal imaging system was recently developed. This paper reports the reliability of this device for temperature assessment of healthy feet. Methods Plantar skin foot temperatures were measured with the novel thermal imaging device (Diabetic Foot Ulcer Prevention System (DFUPS), constructed by Photometrix Imaging Ltd) and also with a hand-held infrared spot thermometer (ThermofocusÂź 01500A3, Tecnimed, Italy) after 20Â min of barefoot resting with legs supported and extended in 105 subjects (52 males and 53 females; age range 18 to 69Â years) as part of a multicentre clinical trial. The temperature differences between the right and left foot at five regions of interest (ROIs), including 1st and 4th toes, 1st, 3rd and 5th metatarsal heads were calculated. The intra-instrument agreement (three repeated measures) and the inter-instrument agreement (hand-held thermometer and thermal imaging device) were quantified using intra-class correlation coefficients (ICCs) and the 95% confidence intervals (CI). Results Both devices showed almost perfect agreement in replication by instrument. The intra-instrument ICCs for the thermal imaging device at all five ROIs ranged from 0.95 to 0.97 and the intra-instrument ICCs for the hand-held-thermometer ranged from 0.94 to 0.97. There was substantial to perfect inter-instrument agreement between the hand-held thermometer and the thermal imaging device and the ICCs at all five ROIs ranged between 0.94 and 0.97. Conclusions This study reports the performance of a novel thermal imaging device in the assessment of foot temperatures in healthy volunteers in comparison with a hand-held infrared thermometer. The newly developed thermal imaging device showed very good agreement in repeated temperature assessments at defined ROIs as well as substantial to perfect agreement in temperature assessment with the hand-held infrared thermometer. In addition to the reported non-inferior performance in temperature assessment, the thermal imaging device holds the potential to provide an instantaneous thermal image of all sites of the feet (plantar, dorsal, lateral and medial views). Trial registration Diabetic Foot Ulcer Prevention System NCT02317835, registered December 10, 201
Potential for improved radiation thermometry measurement uncertainty through implementing a primary scale in an industrial laboratory
A primary temperature scale requires realising a unit in terms of its definition. For high
temperature radiation thermometry in terms of the International Temperature Scale of 1990
this means extrapolating from the signal measured at the freezing temperature of gold, silver
or copper using Planckâs radiation law. The difficulty in doing this means that primary scales
above 1000 °C require specialist equipment and careful characterisation in order to achieve the
extrapolation with sufficient accuracy. As such, maintenance of the scale at high temperatures
is usually only practicable for National Metrology Institutes, and calibration laboratories have
to rely on a scale calibrated against transfer standards. At lower temperatures it is practicable
for an industrial calibration laboratory to have its own primary temperature scale, which
reduces the number of steps between the primary scale and end user. Proposed changes to the
SI that will introduce internationally accepted high temperature reference standards might
make it practicable to have a primary high temperature scale in a calibration laboratory. In
this study such a scale was established by calibrating radiation thermometers directly to high
temperature reference standards. The possible reduction in uncertainty to an end user as a
result of the reduced calibration chain was evaluated
Molecular excitation in the Interstellar Medium: recent advances in collisional, radiative and chemical processes
We review the different excitation processes in the interstellar mediumComment: Accepted in Chem. Re
Using mobile technology to deliver a cognitive behaviour therapy-informed intervention in early psychosis (Actissist): study protocol for a randomised controlled trial
Evaluating the Effects of SARS-CoV-2 Spike Mutation D614G on Transmissibility and Pathogenicity.
Global dispersal and increasing frequency of the SARS-CoV-2 spike protein variant D614G are suggestive of a selective advantage but may also be due to a random founder effect. We investigate the hypothesis for positive selection of spike D614G in the United Kingdom using more than 25,000 whole genome SARS-CoV-2 sequences. Despite the availability of a large dataset, well represented by both spike 614 variants, not all approaches showed a conclusive signal of positive selection. Population genetic analysis indicates that 614G increases in frequency relative to 614D in a manner consistent with a selective advantage. We do not find any indication that patients infected with the spike 614G variant have higher COVID-19 mortality or clinical severity, but 614G is associated with higher viral load and younger age of patients. Significant differences in growth and size of 614G phylogenetic clusters indicate a need for continued study of this variant