408 research outputs found

    Tricarbonylchlorido(6'7'-dihydro-5’H-spiro[cyclopentane-1,6'-dipyrido-[3,2-d:2',3'-f][1,3]diazepine]-κ2N1,N11)-rhenium(I)

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    In the title compound, [ReCl(C15H16N4)(CO)3], the ReI ion is coordinated in a distorted octahedral geometry by one Cl atom, two N atoms of the bidentate ligand and three carbonyl groups. The cyclopentane group is orientated in a transoid fashion with respect to the chloride ligand. The dihedral angle between the pryridine rings is 10.91 (12)°. In the crystal, N-H...Cl hydrogen bonds link complex molecules, forming a two-dimensional network parallel to (001)

    Tricarbonylchlorido(6’,7’-dihydro-5’H-spiro[cyclohexane-1,6’-dipyrido[3,2-d :2’,3’-f][1,3]diazepine]-κ2N1,N11)rhenium(I)

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    In the title compound, [ReCl(C16H18N4)(CO)3], the ReI ion is coordinated in a distorted octahedral geometry by one Cl atom, two N atoms of the bidentate ligand and three carbonyl groups. The cyclohexane group is orientated in a transoid fashion with respect to the chloride ligand. In the crystal, N-H...Cl hydrogen bonds link complex molecules, forming a two-dimensional network parallel to (100)

    Challenges in using hydrology and water quality models for assessing Freshwater Ecosystem Services:A Review

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    Freshwater ecosystems contribute to many ecosystem services, many of which are being threatened by human activities such as land use change, river morphological changes and climate change. Many disciplines have studied the processes underlying freshwater ecosystem functions, ranging from hydrology to ecology, including water quality, and a panoply of models are available to simulate their behaviour. This understanding is useful for the prediction of ecosystem services, but the model outputs must go beyond the production of time-series of biophysical variables, to include notions of value and accessibility to the ecosystems? beneficiaries. This article analyses the literature of ad hoc approaches that aim at quantifying one or more freshwater ecosystem services. It identifies the strategies used to use disciplinary-specific models for the prediction of the services. This review identifies that hydrological, water quality, and ecological models form a valuable knowledge base to predict changes in ecosystem conditions, but challenges remain to make proper and useful use of these models. In particular, considerations of temporal and spatial scales could be given more attention in order to provide better justifications for the choice of a particular model over another, including the uncertainty in their predictions.publishersversionPeer reviewe

    Palliative opioid use, palliative sedation and euthanasia:reaffirming the distinction

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    From PubMed via Jisc Publications RouterHistory: received 2018-11-12, revised 2019-05-08, accepted 2019-05-12Publication status: aheadofprintWe read with interest the extended essay published from Riisfeldt and are encouraged by an empirical ethics article which attempts to ground theory and its claims in the real world. However, such attempts also have real-world consequences. We are concerned to read the paper's conclusion that clinical evidence weakens the distinction between euthanasia and normal palliative care prescribing. This is important. Globally, the most significant barrier to adequate symptom control in people with life-limiting illness is poor access to opioid analgesia. Opiophobia makes clinicians reluctant to prescribe and their patients reluctant to take opioids that might provide significant improvements in quality of life. We argue that the evidence base for the safety of opioid prescribing is broader than that presented, restricting the search to palliative care literature produces significant bias as safety experience and literature for opioids and sedatives exists in many fields. This is not acknowledged in the synthesis presented. By considering additional evidence, we reject the need for agnosticism and reaffirm that palliative opioid prescribing is safe. Second, palliative sedation in a clinical context is a poorly defined concept covering multiple interventions and treatment intentions. We detail these and show that continuous deep palliative sedation (CDPS) is a specific practice that remains controversial globally and is not considered routine practice. Rejecting agnosticism towards opioids and excluding CDPS from the definition of routine care allows the rejection of Riisfeldt's headline conclusion. On these grounds, we reaffirm the important distinction between palliative care prescribing and euthanasia in practice. [Abstract copyright: © Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.

    Control of metallo-supramolecular assemblies via steric, hydrogen bonding and argentophilic interactions; formation of a 3-dimensional polymer of circular helicates

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    This work shows how multiple non-covalent interactions are employed to control metallosupramolecular architectures and we demonstrate that a ligand, which contains two bidentate domains separated by a ArOH spacer, forms a mesocate when complexed with Ag(I). However, changing this to an ArOCH2CH2Ph spacer unit results in a 1-dimensional helical polymer upon reaction with the same cation. Reaction of Ag(I) with the ArOMe derivative gives a hexanuclear circular helicate which forms inter-assembly Ag⋯Ag interactions resulting in a 3-dimensional honeycomb-like polymer of hexanuclear circular helicates

    Evaporation fractionation in a peatland drainage network affects stream water isotope composition

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    There is increasing interest in improving understanding of evaporation within a catchment for an enhanced representation of dominant processes in hydrological models. We used a dual‐isotope approach within a nested experimental design in a boreal catchment in the Scottish Highlands (Bruntland Burn) to quantify the spatiotemporal dynamics of evaporation fractionation in a peatland drainage network and its effect on stream water isotopes. We conducted spatially distributed water sampling within the saturated peatland under different wetness conditions. We used the lc‐excess—which describes the offset of a water sample from the local meteoric water line in the dual‐isotope space—to understand the development of kinetic fractionation during runoff in a peatland network. The evaporation fractionation signal correlated positively with the potential evapotranspiration and negatively with the discharge. The variability of the isotopic enrichment within the peatland drainage network was higher with higher potential evapotranspiration and lower with higher discharge. We found an increased evaporation fractionation toward the center of the peatland, while groundwater seepage from minerogenic soils influenced the isotopic signal at the edge of the peatland. The evaporation signal was imprinted on the stream water, as the discharge from a peatland dominated subcatchment showed a more intense deviation from the local meteoric water line than the discharge from the Bruntland Burn. The findings underline that evaporation fractionation within peatland drainage networks affects the isotopic signal of headwater catchments, which questions the common assumption in hydrological modeling that the isotopic composition of stream waters did not undergo fractionation processes
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