39 research outputs found

    Sustainable polyimidazolium networks as versatile hydrogel materials

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    Stability of the zwitterionic liquid butyl-methyl-imidazol-2-ylidene borane

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    Modification of the C2 position of the standard 1-butyl-3-methyl imidazolium cation by a borohydride group leads to a zwitterionic liquid (ZIL). The resulting imidazol-2-ylidene borane ZIL is liquid at room temperature. Dynamic viscosity as well as thermal and electrochemical stability are investigated. Thermal decomposition follows a similar pathway as in comparable imidazolium ionic liquids. The surprisingly low viscosity and good reductive stability make it a promising candidate for electrochemical applications

    Tunable gas permeation behavior in self-standing cellulose nanocrystal-based membranes

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    Biopolymers arise as environmentally benign alternatives to bio-accumulating, fossil resource-based synthetic polymers for a variety of applications, many of which require self-standing films or membranes. Novel sustainable amine-functionalized cellulose nanocrystals (CNCs) form dense films with low porosity suitable for gas barriers. Due to their brittleness, pure CNC membranes are challenging to work with but represent an attractive support material for selectivity-inducing additives. Supported ionic liquid membranes (SILMs) are promising due to their tunable properties and good performance in gas separation. In this study, we investigate the possibilities to realize such applications by applying glucose and ionic liquids (ILs) as additives with different functions in CNC-based membranes. By the choice of the plasticizer, the gas permeation behavior of the flexible self-standing films can be tuned from impermeable, using glucose as an additive, to permeable by addition of the ILs 1,3-dibutylimidazolium acetate and 1,3-ditetrahydrofurfurylimidazolium acetate. Tunability is also observed through the choice of the CNC source in the form of an inversed selectivity of the gas pair N2/O2, which was traceable to the CNCs’ source-specific properties. The contributions of the matrix and additive were analyzed by comparing CNC to chitosan membranes and considering gas solubilities and diffusivities. The obtained results underline the diversity and tunability of bio-derived functional materials.AB - Biopolymers arise as environmentally benign alternatives to bio-accumulating, fossil resource-based synthetic polymers for a variety of applications, many of which require self-standing films or membranes. Novel sustainable amine-functionalized cellulose nanocrystals (CNCs) form dense films with low porosity suitable for gas barriers. Due to their brittleness, pure CNC membranes are challenging to work with but represent an attractive support material for selectivity-inducing additives. Supported ionic liquid membranes (SILMs) are promising due to their tunable properties and good performance in gas separation. In this study, we investigate the possibilities to realize such applications by applying glucose and ionic liquids (ILs) as additives with different functions in CNC-based membranes. By the choice of the plasticizer, the gas permeation behavior of the flexible self-standing films can be tuned from impermeable, using glucose as an additive, to permeable by addition of the ILs 1,3-dibutylimidazolium acetate and 1,3-ditetrahydrofurfurylimidazolium acetate. Tunability is also observed through the choice of the CNC source in the form of an inversed selectivity of the gas pair Nsub>2/O, which was traceable to the CNCs’ source-specific properties. The contributions of the matrix and additive were analyzed by comparing CNC to chitosan membranes and considering gas solubilities and diffusivities. The obtained results underline the diversity and tunability of bio-derived functional materials

    Renewable pyridinium ionic liquids from the continuous hydrothermal decarboxylation of furfural-amino acid derived pyridinium zwitterions

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    Fully renewable pyridinium ionic liquids were synthesised via the hydrothermal decarboxylation of pyridinium zwitterions derived from furfural and amino acids in flow. The functionality of the resulting ionic liquid (IL) can be tuned by choice of different amino acids as well as different natural carboxylic acids as the counterions. A representative member of this new class of ionic liquids was successfully used for the synthesis of ionogels and as a solvent for the Heck coupling

    Halogen free 1,2,3- and 1,2,4-triazolide based ionic liquids : synthesis and properties

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    Triazoles have been successfully used as building blocks to create "fully organic" ILs featuring on both sides organic ions, i.e., 1,2,3- or 1,2,4-triazolide anions and 1,2,4-triazolium or imidazolium cations. Glass transition temperatures, densities and viscosities of these ILs were determined. Their electrochemical and thermal stability, and also conductivity, are higher than those for known ILs

    Evidence for short range orbital order in paramagnetic insulating (Al,V)_2O_3

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    The local structure of (Al_0.06V_0.94)_2O_3 in the paramagnetic insulating (PI) and antiferromagnetically ordered insulating (AFI) phase has been investigated using hard and soft x-ray absorption techniques. It is shown that: 1) on a local scale, the symmetry of the vanadium sites in both the PI and the AFI phase is the same; and 2) the vanadium 3d - oxygen 2p hybridization, as gauged by the oxygen 1s absorption edge, is the same for both phases, but distinctly different from the paramagnetic metallic phase of pure V_2O_3. These findings can be understood in the context of a recently proposed model which relates the long range monoclinic distortion of the antiferromagnetically ordered state to orbital ordering, if orbital short range order in the PI phase is assumed. The measured anisotropy of the x-ray absorption spectra is discussed in relation to spin-polarized density functional calculations.Comment: 8 pages, 5 figure

    The unusual electronic structure of the "pseudo-ladder" compound CaCu2O3

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    Experimental and theoretical studies of the unoccupied electronic structure of CaCu2O3 single crystals have been performed using polarization-dependent x-ray absorption spectroscopy and band structure calculations. The measured hole distribution shows an unusual large number of holes in orbitals parallel to the interlayer direction which is in agreement with the theoretical analysis. CaCu2O3 deviates significantly from the standard pd-sigma cuprate picture. The corresponding strong interlayer exchange is responsible for the missing spin gap generic for other two-leg ladder cuprates.Comment: 4 pages, 3 figures include

    An AKAP-Lbc-RhoA interaction inhibitor promotes the translocation of aquaporin-2 to the plasma membrane of renal collecting duct principal cells

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    Stimulation of renal collecting duct principal cells with antidiuretic hormone (arginine-vasopressin, AVP) results in inhibition of the small GTPase RhoA and the enrichment of the water channel aquaporin-2 (AQP2) in the plasma membrane. The membrane insertion facilitates water reabsorption from primary urine and fine-tuning of body water homeostasis. Rho guanine nucleotide exchange factors (GEFs) interact with RhoA, catalyze the exchange of GDP for GTP and thereby activate the GTPase. However, GEFs involved in the control of AQP2 in renal principal cells are unknown. The A-kinase anchoring protein, AKAP-Lbc, possesses GEF activity, specifically activates RhoA, and is expressed in primary renal inner medullary collecting duct principal (IMCD) cells. Through screening of 18,431 small molecules and synthesis of a focused library around one of the hits, we identified an inhibitor of the interaction of AKAP-Lbc and RhoA. This molecule, Scaff10-8, bound to RhoA, inhibited the AKAP-Lbc-mediated RhoA activation but did not interfere with RhoA activation through other GEFs or activities of other members of the Rho family of small GTPases, Rac1 and Cdc42. Scaff10-8 promoted the redistribution of AQP2 from intracellular vesicles to the periphery of IMCD cells. Thus, our data demonstrate an involvement of AKAP-Lbc-mediated RhoA activation in the control of AQP2 trafficking

    Effectiveness and safety of opicapone in Parkinson's disease patients with motor fluctuations: The OPTIPARK open-label study

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    BACKGROUND: The efficacy and safety of opicapone, a once-daily catechol-O-methyltransferase inhibitor, have been established in two large randomized, placebo-controlled, multinational pivotal trials. Still, clinical evidence from routine practice is needed to complement the data from the pivotal trials. METHODS: OPTIPARK (NCT02847442) was a prospective, open-label, single-arm trial conducted in Germany and the UK under clinical practice conditions. Patients with Parkinson’s disease and motor fluctuations were treated with opicapone 50 mg for 3 (Germany) or 6 (UK) months in addition to their current levodopa and other antiparkinsonian treatments. The primary endpoint was the Clinician’s Global Impression of Change (CGI-C) after 3 months. Secondary assessments included Patient Global Impressions of Change (PGI-C), the Unified Parkinson’s Disease Rating Scale (UPDRS), Parkinson’s Disease Questionnaire (PDQ-8), and the Non-Motor Symptoms Scale (NMSS). Safety assessments included evaluation of treatment-emergent adverse events (TEAEs) and serious adverse events (SAEs). RESULTS: Of the 506 patients enrolled, 495 (97.8%) took at least one dose of opicapone. Of these, 393 (79.4%) patients completed 3 months of treatment. Overall, 71.3 and 76.9% of patients experienced any improvement on CGI-C and PGI-C after 3 months, respectively (full analysis set). At 6 months, for UK subgroup only (n = 95), 85.3% of patients were judged by investigators as improved since commencing treatment. UPDRS scores at 3 months showed statistically significant improvements in activities of daily living during OFF (mean ± SD change from baseline: − 3.0 ± 4.6, p < 0.0001) and motor scores during ON (− 4.6 ± 8.1, p < 0.0001). The mean ± SD improvements of − 3.4 ± 12.8 points for PDQ-8 and -6.8 ± 19.7 points for NMSS were statistically significant versus baseline (both p < 0.0001). Most of TEAEs (94.8% of events) were of mild or moderate intensity. TEAEs considered to be at least possibly related to opicapone were reported for 45.1% of patients, with dyskinesia (11.5%) and dry mouth (6.5%) being the most frequently reported. Serious TEAEs considered at least possibly related to opicapone were reported for 1.4% of patients. CONCLUSIONS: Opicapone 50 mg was effective and generally well-tolerated in PD patients with motor fluctuations treated in clinical practice. TRIAL REGISTRATION: Registered in July 2016 at clinicaltrials.gov (NCT02847442)

    Transverse momentum spectra of charged particles in proton-proton collisions at s=900\sqrt{s} = 900 GeV with ALICE at the LHC

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    The inclusive charged particle transverse momentum distribution is measured in proton-proton collisions at s=900\sqrt{s} = 900 GeV at the LHC using the ALICE detector. The measurement is performed in the central pseudorapidity region (η<0.8)(|\eta|<0.8) over the transverse momentum range 0.15<pT<100.15<p_{\rm T}<10 GeV/cc. The correlation between transverse momentum and particle multiplicity is also studied. Results are presented for inelastic (INEL) and non-single-diffractive (NSD) events. The average transverse momentum for η<0.8|\eta|<0.8 is <pT>INEL=0.483±0.001\left<p_{\rm T}\right>_{\rm INEL}=0.483\pm0.001 (stat.) ±0.007\pm0.007 (syst.) GeV/cc and \left_{\rm NSD}=0.489\pm0.001 (stat.) ±0.007\pm0.007 (syst.) GeV/cc, respectively. The data exhibit a slightly larger <pT>\left<p_{\rm T}\right> than measurements in wider pseudorapidity intervals. The results are compared to simulations with the Monte Carlo event generators PYTHIA and PHOJET.Comment: 20 pages, 8 figures, 2 tables, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/390
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