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  • 1
    Language: English
    In: Journal of the American Chemical Society, 23 September 2015, Vol.137(37), pp.12110-20
    Description: In contrast to hydrogen bonding, which is firmly established in organocatalysis, there are still very few applications of halogen bonding in this field. Herein, we present the first catalytic application of cationic halogen-bond donors in a halide abstraction reaction. First, halopyridinium-, haloimidazolium-, and halo-1,2,3-triazolium-based catalysts were systematically tested. In contrast to the pyridinium compounds, both the imidazolium and the triazolium salts showed promising potency. For the haloimidazolium-based organocatalysts, we could show that the catalytic activity is based on halogen bonding using, e.g., the chlorinated derivatives as reference compounds. On the basis of these studies, halobenzimidazolium organocatalysts were then investigated. Monodentate compounds featured the same trends as the corresponding imidazolium analogues but showed a stronger catalytic activity. In order to prepare bidentate versions which are preorganized for anion binding, a new class of rigid bis(halobenzimidazolium) compounds was synthesized and structurally characterized. The corresponding syn isomer showed unprecedented catalytic potency and could be used in as low as 0.5 mol % in the benchmark reaction of 1-chloroisochroman with a silyl enol ether. Calculations confirmed that the syn isomer may bind in a bidentate fashion to chloride. The respective anti isomer is less active and binds halides in a monodentate fashion. Kinetic investigations confirmed that the syn isomer led to a 20-fold rate acceleration compared to a neutral tridentate halogen-bond donor. The strength of the preorganized halogen-bond donor seems to approach the limit under the reaction conditions, as decomposition is observed in the presence of chloride in the same solvent at higher temperatures. Calorimetric titrations of the syn isomer with bromide confirmed the strong halogen-bond donor strength of the former (K ≈ 4 × 10(6) M(-1), ΔG ≈ 38 kJ/mol).
    Keywords: Halogens ; Catalyst-Activity ; Isomers ; Chlorides ; Pyridinium-Compounds ; Hydrogen ; Anions ; Solvents ; Acceleration ; Titration ; Reaction-Condition ; Compound-Strength ; High-TC ; Halogene ; Katalytische Aktivität ; Isomer ; Chlorid ; Pyridiniumverbindung ; Wasserstoff ; Anion ; Lösungsmittel ; Beschleunigung ; Titration ; Reaktionsbedingung ; Verbundfestigkeit ; Hochtemperatur ; Chemistry;
    ISSN: 00027863
    E-ISSN: 1520-5126
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  • 2
    Language: English
    In: Journal of Chromatography A, 2011, Vol.1218(17), pp.2374-2380
    Description: We have developed a method for quantification of a specific monoclonal IgM directed toward embryonic stem cells based on a peptide affinity monolith. A peptide affinity ligand with the sequence C–C–H–Q–R–L–S–Q–R–K was obtained by epitope mapping using peptide SPOT synthesis. The peptide ligand was covalently immobilized by coupling the N-terminal cysteine to a monolithic disk that was previously modified with iodated spacer molecules. The monolithic disc was used for quantification of purified IgM and for IgM present in mammalian cell culture supernatant. We observed 17% unspecific binding of IgM to the monolithic disk and additionally a product loss in the flow through of 20%. Nevertheless, calibration curves had high correlation coefficients and inter/intra-assay variability experiments proved sufficient precision of the method. A limit of quantification of 51.69 μg/mL for purified IgM and 48.40 μg/mL for IgM in cell culture supernatant could be calculated. The binding capacity was consistent within the period of the study which included more than 200 cycles. The analysis time of less than 2 min is an advantage over existing chromatographic methods that rely on pore diffusion.
    Keywords: Peptide Spot Synthesis ; Igm ; Antibody ; Monolith ; Convective Interaction Media ; Chemistry
    ISSN: 0021-9673
    E-ISSN: 18733778
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  • 3
    Language: English
    In: Chemistry – A European Journal, 21 September 2015, Vol.21(39), pp.13625-13636
    Description: The binding properties of neutral halogen‐bond donors (XB donors) bearing two multidentate Lewis acidic motifs toward halides were investigated. Employing polyfluorinated and polyiodinated terphenyl and quaterphenyl derivatives as anion receptors, we obtained X‐ray crystallographic data of the adducts of three structurally related XB donors with tetraalkylammonium chloride, bromide, and iodide. The stability of these XB complexes in solution was determined by isothermal titration calorimetry (ITC), and the results were compared to X‐ray analyses as well as to calculated binding patterns in the gas phase. Density functional theory (DFT) calculations on the gas‐phase complexes indicated that the experimentally observed distortion of the XB donors during multiple multidentate binding can be reproduced in 1:1 complexes with halides, whereas adducts with two halides show a symmetric binding pattern in the gas phase that is markedly different from the solid state structures. Overall, this study demonstrates the limitations in the transferability of binding data between solid state, solution, and gas phase in the study of complex multidentate XB donors. of neutral halogen bond donors bearing two multidentate Lewis acidic sites toward chloride, bromide, and iodide were investigated by X‐ray structural analyses, isothermal titration calorimetry, and density functional calculations. This study demonstrates that the transferability of the binding data of such complexes between the solid state, solution, and gas phase has severe limitations.
    Keywords: Anions ; Halogen Compounds ; Molecular Recognition ; Noncovalent Interactions ; Thermodynamics
    ISSN: 0947-6539
    E-ISSN: 1521-3765
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  • 4
    Language: English
    In: Chemistry - A European Journal, Oct 26, 2015, Vol.21(44), p.15467(1)
    Description: To purchase or authenticate to the full-text of this article, please visit this link: http://onlinelibrary.wiley.com/doi/10.1002/chem.201503723/abstract Byline: Stefan H. Jungbauer, Severin Schindler, Eberhardt Herdtweck, Sandro Keller, Stefan M. Huber Keywords: anions; halogen compounds; molecular recognition; noncovalent interactions; thermodynamics ***** No abstract is available for this article. *****
    ISSN: 0947-6539
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  • 5
    Language: English
    In: Child and Adolescent Social Work Journal, 2014, Vol.31(2), pp.181-196
    Description: This article presents results from an in-depth interview study investigating challenges and coping strategies of children with parents affected by schizophrenia. Thirty-four qualitative interviews of children were conducted and evaluated by content analysis. The interviewees spoke of a wide range of challenges that they must deal with daily. A variety of available coping strategies, social and personal resources were identified in the study. The results show that there is a need for professional support, especially on a low-threshold basis, that helps affected children to develop appropriate and diverse forms of coping.
    Keywords: Children ; Parents affected by schizophrenia ; Challenges ; Coping ; Individual resources
    ISSN: 0738-0151
    E-ISSN: 1573-2797
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  • 6
    Language: English
    In: Journal of Applied Physics, May 7, 2013, Vol.113(17), p.17D709-1-17D709-3
    Description: The exchange bias (EB) observed in [La.sub.0.7][Sr.sub.0.3]Mn[O.sub.3]/SrMn[O.sub.3]/ [La.sub.0.7][Sr.sub.0.3]Mn[O.sub.3] trilayers is explained. It is suggested that the interplay of a spinglass state at the interface and theoretically proposed mechanism based on the Dzyaloshinskii-Moriya interaction can help in explaining this EB behaviour.
    Keywords: Chemical Vapor Deposition -- Methods ; Electron-electron Interactions -- Analysis ; Magnetic Hysteresis -- Analysis ; Strontium Compounds -- Magnetic Properties ; Strontium Compounds -- Thermal Properties
    ISSN: 0021-8979
    Source: Cengage Learning, Inc.
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  • 7
    Language: English
    In: Proceedings Of The 55th Annual Conference On Magnetism And Magnetic Materials, Atlanta, Georgia (14-18 November 2010):
    In: Journal of Applied Physics, 07 May 2013, Vol.113(17)
    Description: We report ferromagnetic, T C = 240   K , and metallic, T MI = 250   K , behaviors of a three unit cell thick interface engineered lanthanum manganite film, grown by metalorganic aerosol deposition technique on SrTiO 3 (100) substrates. Atomically resolved electron microscopy and chemical analysis show that ultrathin manganite films start to grow with La-O layer on a strongly Mn/Ti-intermixed interface, engineered by an additional deposition of 2 u.c. of Sr-Mn-O. Such interface engineering results in a hole-doped manganite layer and stabilizes ferromagnetism and metallic conductivity down to the thickness of d = 3 u.c. The films with d  = 8 u.c. demonstrate a bulk-like transport behavior with T MI ∼ T C = 310 − 330   K .
    Keywords: Proceedings Of The 12th Joint Mmm-Intermag Conference
    ISSN: 0021-8979
    E-ISSN: 1089-7550
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  • 8
    Language: English
    In: Trends in Biotechnology, August 2013, Vol.31(8), pp.479-492
    Description: Continuous manufacturing has been applied in many different industries but has been pursued reluctantly in biotechnology where the batchwise process is still the standard. A shift to continuous operation can improve productivity of a process and substantially reduce the footprint. Continuous operation also allows robust purification of labile biomolecules. A full set of unit operations is available to design continuous downstream processing of biopharmaceuticals. Chromatography, the central unit operation, is most advanced in respect to continuous operation. Here, the problem of ‘batch’ definition has been solved. This has also paved the way for implementation of continuous downstream processing from a regulatory viewpoint. Economic pressure, flexibility, and parametric release considerations will be the driving force to implement continuous manufacturing strategies in future.
    Keywords: Engineering ; Chemistry
    ISSN: 0167-7799
    E-ISSN: 1879-3096
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  • 9
    Language: English
    In: Transfusion and Apheresis Science, 2011, Vol.45(1), pp.61-68
    Description: During the last decade a number of blood establishments started using molecular methods for typing a subset of their blood donors for minor red cell antigens as a part of their routine work. It can be expected that this development will continue and that DNA testing will take a significant role in future. A sufficient number of antigen-typing in the donor-database allows for the efficient supply of red cell units for patients who carry irregular antibodies directed to red cell antigens. Therefore blood centres often operate antigen typing programs for a subset of their repeat donors. Large-scale donor typing programs are labour-intensive and costly. DNA testing is a feasible alternative to standard serological assays. The most important advantage is the easy access to a spectrum of hundreds of antigens independent of the availability of serological reagents. Besides, that there are both positive, but also less favourable aspects, which are related to the different particular methods and platforms available for molecular testing. Several of them enable medium- and high-throughput applications and some are more cost-efficient than serology.
    Keywords: Medicine
    ISSN: 1473-0502
    E-ISSN: 1878-1683
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  • 10
    Language: English
    In: Journal of Chromatography A, Dec 6, 2013, Vol.1319, p.107(11)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.chroma.2013.10.039 Byline: Martin Wellhoefer, Wolfgang Sprinzl, Rainer Hahn, Alois Jungbauer Abstract: acents A chromatographic refolding method which saves up to 99% refolding buffer. acents The methods shifts refolding equilibrium. acents The method can be connected to a purification step. Author Affiliation: (a) Austrian Centre of Industrial Biotechnology (ACIB), Muthgasse 11, 1190 Vienna, Austria (b) Department of Biotechnology, University of Natural Resources and Life Sciences Vienna, Muthgasse 18, 1190 Vienna, Austria Article History: Received 6 August 2013; Revised 8 October 2013; Accepted 9 October 2013
    Keywords: Recycling ; Chromatography ; Recombinant Proteins
    ISSN: 0021-9673
    Source: Cengage Learning, Inc.
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