1,626 research outputs found
Do we need summary and sequential scanning in (Cognitive) grammar?
No full textCognitive Grammar postulates two modes of cognitive processing for the structuring of complex scenes, summary scanning and sequential scanning. Generally speaking, the theory is committed to basing grammatical concepts upon more general cognitive principles. In the case of summary and sequential scanning, independent evidence is lacking, but Langacker argues that the distinction should nonetheless be accepted as it buys us considerable theory-internal explanatory power. For example, dynamic prepositions, to-infinitives and participles (e.g., into, to enter, entered) are distinguished from finite and bare verbs in terms of summary vs. sequential scanning. In this paper, we try to show that various theory-internal and theory-external arguments do not seem to support the two scanning modes. In particular, we offer a detailed examination of causatives (e.g., get, make) and argue that their complementation patterns are difficult to reconcile with differences in scanning. We conclude that the status of, and need for, summary and sequential scanning in (Cognitive) grammar is doubtful, especially if grammar is approached from the viewpoint of the language learner/user. It follows also that the parcelling of some form-function mappings may prove less clear-cut than previously assumed
Gras- und Kleesaaten, Gewinnung und Handel in Dänemark, Grossbritannien und Irland.
No full text[Pt. 1] issued separately as Hollmann. Gras- und Kleesamengewinnung in Dänemark, Stück 19 of Berichte über Land- und Forstwirtschaft im Ausland.[Pt. 1] Gras- und Kleesamengewinnung in Dänemark. Von dr. Hollmann.--[Pt. 2] Klee- und Grassaaten, Gewinnung und Handel in Grossbritannien und Irland. Von dr. Skalweit.Mode of access: Internet
Biocatalytic C=C Bond Reduction through Carbon Nanodot-Sensitized Regeneration of NADH Analogues
No full textLight-driven activation of redox enzymes is an emerging route for sustainable chemical synthesis. Among redox enzymes, the family of Old Yellow Enzyme (OYE) dependent on the nicotinamide adenine dinucleotide cofactor (NADH) catalyzes the stereoselective reduction of α,β-unsaturated hydrocarbons. Here, we report OYE-catalyzed asymmetric hydrogenation through light-driven regeneration of NADH and its analogues (mNADHs) by N-doped carbon nanodots (N-CDs), a zero-dimensional photocatalyst. Our spectroscopic and photoelectrochemical analyses verified the transfer of photo-induced electrons from N-CDs to an organometallic electron mediator (M) for highly regioselective regeneration of cofactors. Light triggered the reduction of NAD+ and mNAD+s with the cooperation of N-CDs and M, and the reduction behaviors of cofactors were dependent on their own reduction peak potentials. The regenerated cofactors subsequently delivered hydrides to OYE for stereoselective conversions of a broad range of substrates with excellent biocatalytic efficiencies.</p
Visualizing simultaneous stochastic microevents macroscopically: Nucleation processes with large ions leading to ionic crystals
No full textMüller A, Diemann E, Hollmann B, Ratajczak H. Visualizing simultaneous stochastic microevents macroscopically: Nucleation processes with large ions leading to ionic crystals. NATURWISSENSCHAFTEN. 1996;83(7):321-322
Motivational Antecedents and Consequences of the Mother–Adolescent Communication
No full textHollmann J, Gorges J, Wild E. Motivational Antecedents and Consequences of the Mother–Adolescent Communication. Journal of Child and Family Studies. 2016;25(3):767-780
Der Erwerb sprachlicher Kompetenzen im Elternhaus - Erste Befunde zur Güte eines Fragebogens zur Erfassung des Anregungsgehaltes von Familienkonversationen
No full textHollmann J, Wild E, Quasthoff U, Krah A, Otterpohl N. Der Erwerb sprachlicher Kompetenzen im Elternhaus - Erste Befunde zur Güte eines Fragebogens zur Erfassung des Anregungsgehaltes von Familienkonversationen. Unterrichtswissenschaft. 2012;40(1):47-63
Novel approaches for biocatalytic oxyfunctionalization reactions
No full textBiocatalytic oxyfunctionalizations, especially of non - activated hydrocarbons, attract considerable attention for synthetic organic chemistry thanks to their high chemo-, regio-, and stereoselectivity, which difficult to achieve by chemical means. Many enzymatic oxyfunctionalizations have been described. However, there are many hurdles towards large scale applications, such as low activity and stability of enzymes, substrate toxicity, overoxidation, oxygen mass transfer, etc. Therefore, the aim of this thesis is to setup robust and scalable biocatalytic oxyfunctionalizations. Chapter 1 gives a general introduction on enzymatic C-H oxyfunctionalizations highlighting the great potential of heme - iron peroxygenases. Peroxygenases do not rely on expensive NAD(P)H cofactors and catalyze a variety of useful synthetic transformations utilizing H2O2 as an oxidant. However, the practical applicability of heme - peroxygenases is limited by their low stability towards H2O2. To avoid the inactivation of the enzymes, we have developed two alternative catalytic approaches for the controlled in situ H2O2 generation from O2. General applicability of the proposed methods has been demonstrated for various peroxygenase - based biotransformations in Chapters 2, 3, 4. Thus, in Chapter 2 a photocatalytic approach for in situ H2O2 generation has been applied for the CPO (chloroperoxidase from Caldariomyces fumago) catalyzed thioanisole sulfoxidation. The enzyme stability has been drastically improved; however, the productivity of the system was severely limited by low solubility and evaporation of the substrate. Therefore, the photocatalytic approach was demonstrated at preparative - scale using a surfactant - stabilized two – liquid phase system (2 LPS). Both, initial rate and robustness of the system could be enhanced significantly leading to an increase of the final product concentration by more than one order of magnitude in comparison with monophasic set - up. In Chapter 3 the proposed photocatalytic in situ generation of H2O2 proved to be a suitable approach for AaeAPO (Agrocybe aegerita aromatic peroxygenase) catalyzed epoxidation and hydroxylation reactions. High productivities and excellent enantiomeric excesses (>97%) were obtained with a broad range of substrates. Furthermore, preliminary results indicate that hundreds of thousands of turnovers can be achieved after reaction engineering, demonstrating the high potential of AaeAPO for oxyfunctionalization catalysis. In Chapter 4 an alternative in situ H2O2 generation method has been developed using a synthetic nicotinamide cofactor mimic and flavin. This method has been applied for the specific ?- or ?-hydroxylation of fatty acid catalyzed by the cytochrome P450 peroxygenases. The cytochrome P450 peroxygenases P450bs? from Bacillus subtilis and P450cl? from Clostridium acetobutylicum belong to a unique group of P450s which consume H2O2 and therefore do not require additional electron transfer proteins and NAD(P)H cofactor. Using the new method for in situ H2O2 generation the final productivity of P450 peroxygenases could be enhanced due to higher enzyme stability under operation conditions. In addition to peroxygenases, various oxyfunctionalizations can be performed by oxygenases. However, the application of isolated oxygenases, relies on efficient cofactor regeneration techniques. Formate dehydrogenase (FDH) is widely applied for NAD(P)H regeneration. However, classical FDH -based reaction systems are limited to mainly aqueous media, wherein the majority of substrates are poorly soluble. In order to circumvent this limitation we propose in Chapter 6 using formic acid esters as ‘hydrophobized’ formic acid equivalents, which simultaneously can serve as an organic phase in 2LPS reaction and as source of reducing equivalents. The concept was demonstrated using 2-hydroxybiphenyl-3-monooxygenase (HbpA)-catalyzed specific ortho-hydroxylation of phenols as model reaction. In addition, chemical methods for NAD(P)H regeneration have been employed as an alternative to enzymatic methods. The organometallic compound [Cp*Rh(bpy)(H2O)]2+ has emerged as a catalyst of choice. However, the mutual inactivation between [Cp*Rh(bpy)(H2O)]2+ and enzymes is usually encountered. To overcome this issue, in Chapter 5, we propose using artificial transfer hydrogenases (ATHs) wherein the biotin - coordinated transition metal complex is sterically shielded by complexation with streptavidin. Thereby, the mutual inactivation of the regeneration catalysts and the production enzyme(s) can be efficiently circumvented. The applicability of the concept was illustrated by combining the ATHase with HbpA, demonstrating that the general catalytic properties of ATHase and enzyme are preserved. In conclusion, this thesis addresses some major challenges of oxyfunctionalization catalysis including enzyme stability, cofactor dependency and substrate supply. The proposed methods to overcome these issues have been implemented to various enzymatic oxyfunctionalizations. Furthermore, their practical applicability has been demonstrated at preparative - scale using a two liquid phase approach. Promising results in terms of productivity and selectivity have been obtained, thereby paving the way to preparative biocatalytic oxyfunctionalization. Nevertheless, further studies, e.g. combining enzyme immobilization techniques with reaction and process engineering, are needed to substantiate the full potential of biocatalytic oxyfunctionalizations.BiotechnologyApplied Science
You Will Attain My Goal—The Structure of Parental Goals for Children Based on an Adapted Version of the Aspirations Index
No full textHollmann J, Gorges J, Wild E. You Will Attain My Goal—The Structure of Parental Goals for Children Based on an Adapted Version of the Aspirations Index. European Journal of Psychological Assessment. 2018;34(1):22-29
Eine längsschnittliche Untersuchung des Zusammenspiels von domänenspezifischem Fähigkeitsselbstkonzept und Interesse bei Schülerinnen und Schülern mit sonderpädagogischem Förderbedarf Lernen
No full textStranghöner D, Hollmann J, Gorges J, Wild E. Eine längsschnittliche Untersuchung des Zusammenspiels von domänenspezifischem Fähigkeitsselbstkonzept und Interesse bei Schülerinnen und Schülern mit sonderpädagogischem Förderbedarf Lernen. Empirische Pädagogik. 2017;31(3):249-264
Control of the vortex flow in microchannel arrays produced in YBCO films by heavy-ion lithography
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