1,395 research outputs found
Synthesis, structure and pyrolysis of stabilised phosphonium ylides containing saturated oxygen heterocycles
yesA range of twelve stabilised phosphonium ylides containing tetrahydrofuran, tetrahydropyran or 2,2-
dimethyl-1,3-dioxolane rings have been prepared and fully characterised, including one X-ray structure
determination of each type. The X-ray structures confirm the PvC and CvO functions to be syn and all
the compounds undergo thermal extrusion of Ph3PO to give the corresponding alkynes. In some cases
there is also competing loss of Ph3P to give different carbene-derived products and evidence has been
obtained for the generation of 2-phenyloxete in this way. Raising the pyrolysis temperature leads in
several cases to new secondary reactions of the alkyne products involving a sequence of alkyne to vinylidene
isomerisation, intramolecular CH insertion, and retro Diels Alder reaction
Real-time single image and video super-resolution using an efficient sub-pixel convolutional neural network
Recently, several models based on deep neural networks have achieved great success in terms of both reconstruction accuracy and computational performance for single image super-resolution. In these methods, the low resolution (LR) input image is upscaled to the high resolution (HR) space using a single filter, commonly bicubic interpolation, before reconstruction. This means that the super-resolution (SR) operation is performed in HR space. We demonstrate that this is sub-optimal and adds computational complexity. In this paper, we present the first convolutional neural network (CNN) capable of real-time SR of 1080p videos on a single K2 GPU. To achieve this, we propose a novel CNN architecture where the feature maps are extracted in the LR space. In addition, we introduce an efficient sub-pixel convolution layer which learns an array of upscaling filters to upscale the final LR feature maps into the HR output. By doing so, we effectively replace the handcrafted bicubic filter in the SR pipeline with more complex upscaling filters specifically trained for each feature map, whilst also reducing the computational complexity of the overall SR operation. We evaluate the proposed approach using images and videos from publicly available datasets and show that it performs significantly better (+0.15dB on Images and +0.39dB on Videos) and is an order of magnitude faster than previous CNN-based methods
Real-time single image and video super-resolution using an efficient sub-pixel convolutional neural network
Recently, several models based on deep neural networks have achieved great success in terms of both reconstruction accuracy and computational performance for single image super-resolution. In these methods, the low resolution (LR) input image is upscaled to the high resolution (HR) space using a single filter, commonly bicubic interpolation, before reconstruction. This means that the super-resolution (SR) operation is performed in HR space. We demonstrate that this is sub-optimal and adds computational complexity. In this paper, we present the first convolutional neural network (CNN) capable of real-time SR of 1080p videos on a single K2 GPU. To achieve this, we propose a novel CNN architecture where the feature maps are extracted in the LR space. In addition, we introduce an efficient sub-pixel convolution layer which learns an array of upscaling filters to upscale the final LR feature maps into the HR output. By doing so, we effectively replace the handcrafted bicubic filter in the SR pipeline with more complex upscaling filters specifically trained for each feature map, whilst also reducing the computational complexity of the overall SR operation. We evaluate the proposed approach using images and videos from publicly available datasets and show that it performs significantly better (+0.15dB on Images and +0.39dB on Videos) and is an order of magnitude faster than previous CNN-based methods
4-Chlorobenzyl chloride
The X-ray structure of the title compound has been determined for the first time. Its molecular structure is in good agreement with those previously determined for similar benzyl halides and the angles between the ring–Cl bonds in adjacent molecules show values in good agreement with an early Zeeman quadrupole spectroscopy study.Publisher PDFPeer reviewe
5-Amino-3-methyl-1,2,4-thiadiazole
An improved procedure for isolation of 5-amino-3-methyl-1,2,4-thiadiazole in pure form on a multi-gram scale without chromatography is reported. Its 1H and 13C NMR and IR data are presented and previously published erroneous data corrected. The molecular structure is confirmed by X-ray diffraction which shows layers consisting of an elaborate two-dimensional hydrogen bonded network of moleculesPublisher PDFPublisher PDFPeer reviewe
3,5-Dithiatricyclo[5.2.1.02,6]decan-2-one
The X-ray structure of the title compound has been determined and the structure shows an exo-configured planar dithiolanone ring. This is in contrast to the few previous dithiolanones to be characterised crystallographically which are all twisted.Publisher PDFPeer reviewe
Rationalisation of patterns of competing reactivity by X-ray structure determination : reaction of isomeric (benzyloxythienyl)oxazolines with a base
Funding: We thank EPSRC (UK) for a DTA studentship to ADH (Grant EP/L505079/1) and the EPSRC UK National Mass Spectrometry Facility at Swansea University.Three isomeric (benzyloxythienyl)oxazolines 9 , 11 and 13 have been prepared and are found, upon treatment with strong base, to undergo either Wittig rearrangement or intramolecular attack of the benzylic anion on the oxazoline function to give products derived from cleavage of the initially formed 3-aminothienofuran products. This pattern of reactivity is directly linked to the distance between the two reactive groups as determined by X-ray diffraction, with the greatest distance in 11 leading to exclusive Wittig rearrangement, the shortest distance in 13 giving exclusively cyclisation-derived products, and the intermediate distance in 9 leading to both processes being observed. The corresponding N-butyl amides were also obtained in two cases and one of these undergoes efficient Wittig rearrangement leading to a thieno[2,3-c]pyrrolone product.Publisher PDFPeer reviewe
Structure and NMR spectra of bicyclo[2.2.1]hepta-2,5-diene-2,3-dicarboxylic acid and its anhydride
Two of the three published sets of 1H and 13C NMR data for bicyclo[2.2.1]hepta-2,5-diene-2,3-dicarboxylic anhydride have been found to actually be those of the corresponding diacid. The NMR spectroscopic distinction between these two compounds is clarified and 1JC–H values are reported for the anhydride, the diacid and a related diester. The X-ray structure of the diacid has been determined and features chains of molecules involving both intra- and inter-molecular hydrogen bonding.PostprintPeer reviewe
The role of brokering in healthcare networks: what does it mean for reforms, practitioners and patients?
Well-integrated systems are required to deliver effective healthcare services. Research suggests misaligned organisational and functional boundaries still thwart effective patient care. Using social network theory and knowledge transfer framework we examine two long-term condition health networks where brokering occurs to bridge the gaps in provision or information exchange. The experiences of patients, relatives and healthcare practitioners illustrate where information/knowledge is transferred, translated and transformed across organisational and functional boundaries. We propose brokering is essential to the integrated healthcare system. Areas of further research include power of brokers and the value and cost of brokering
2,6-exo-8,10-exo-4-Butyl-9-oxa-4-azatetracyclo[5.3.1.02,6.08,10]undecane-3,5-dione
The title epoxide was obtained by spontaneous epoxidation of the corresponding unsaturated imide in air or by peracid oxidation. Unambiguous assignment of the 1H and 13C NMR spectra is achieved by comparison between analogous compounds and its X-ray structure confirms the exo,exo-configuration.Publisher PDFPeer reviewe
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