72 research outputs found

    A simplified framework for first-order languages and its formalization in Mizar

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    A strictly formal, set-theoretical treatment of classical first-order logic is given. Since this is done with the goal of a concrete Mizar formalization of basic results (Lindenbaum lemma; Henkin, satisfiability, completeness and Lowenheim-Skolem theorems) in mind, it turns into a systematic pursue of simplification: we give up the notions of free occurrence, of derivation tree, and study what inference rules are strictly needed to prove the mentioned results. Afterwards, we discuss details of the actual Mizar implementation, and give general techniques developed therein.Comment: Ph.D. thesis, defended on January, 20th, 201

    Inorganic-organic hybrid double sulfates as catalysts of the diastereoselective nitroaldol reaction

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    International audienceBis(1-phenylethanaminium) disulfatotetraaquazincate(II) dihydrate (C8H12N)2[Zn(H2O)4(SO4)2]*2H2O (1), bis(1H-benzo[d]imidazolium) hexaaquazinc(II) bis(sulfate) tetrahydrate (C7H7N2)2[Zn(H2O)6](SO4)2*4H2O (2) and bis(2-methyl-1H-imidazolium) hexaaquazinc(II) bis(sulfate) dihydrate (C4H7N2)2[Zn(H2O)6](SO4)2*2H2O (3) have been synthesized and fully structurally characterized including single-crystal X-ray diffraction analysis. 1-3 are organically templated hybrid layered materials comprising aquazinc(II) and aminium cations and sulfate anions. 1-3 are effective catalysts in the asymmetric Henry reaction; 1 being the most efficient one (yields up to 85% and threo/erythro diastereoselectivity up to 89:11)

    The Nature and Impact of Service Employees’ Innovative Behaviour; a personal-interactive services perspective

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    The amount of research on service innovation rapidly increased since the start of the third millennium, likely due to the continuous diversification of manufacturing companies into the service sector and the decline of manufacturing in the traditional industrial western countries compared to the World’s emerging economies. Service innovation, furthermore, has received significant attention from academics and practitioners alike and has been increasingly perceived as a means of creating competitive advantage. Arguably, this is due to the growing competition between service companies to reach unconventional levels which led to higher customer expectations of continuous improvement of services.This study investigated the nature and impact of service employees’ innovative behaviour leading to initiating innovation within the sub-sector of personal-interactive services, where the hotel sector was investigated respectively. In doing so, the study also critically reviewed the established literature relevant to service innovation and added further insight to previous research underpinning service employees’ role in initiating innovation.A qualitative case-study research strategy, which compared between three cases, was applied to achieve the objectives of the study. The application of qualitative case-study research allowed closer assessment and observation while the researcher was directly present within the service delivery environment. The combining of qualitative research methods, such as semi-structured interviews, focus groups and direct observation, was applied to congregate evidence of employees’ innovative behaviour patterns from multiple perspectives. The expected limitations of the applied research methods are classically associated with qualitative case-study research such as access barriers, high volume of data outcome and also the complications associated with data collection and analysis.The research findings contributed to the general body of knowledge by highlighting the nature and impact of service employees’ innovative behaviour. A novel classification of six innovative behaviour patterns was established under the three main categories of mandatory, quasi-mandatory and voluntary conduct. The research findings further revealed the significant impact of service employees’ innovative behaviour in initiating innovation, where 49 out of 70 innovative ideas were realised as innovations through employees’ innovative behaviour. The research also added further insight by identifying management procedures and motivation as contextual determinants that enable or inhibit service employees’ innovative behaviour

    Naphthoquinone-mediated inhibition of lysine acetyltransferase KAT3B/p300, basis for non-toxic inhibitor synthesis

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    Hydroxynaphthoquinone-based inhibitors of the lysine acetyltransferase KAT3B (p300), such as plumbagin, are relatively toxic. Here, we report that free thiol reactivity and redox cycling properties greatly contribute to the toxicity of plumbagin. A reactive 3rd position in the naphthoquinone derivatives is essential for thiol reactivity and enhances redox cycling. Using this clue, we synthesized PTK1, harboring a methyl substitution at the 3rd position of plumbagin. This molecule loses its thiol reactivity completely and its redox cycling ability to a lesser extent. Mechanistically, non-competitive, reversible binding of the inhibitor to the lysine acetyltransferase (KAT) domain of p300 is largely responsible for the acetyltransferase inhibition. Remarkably, the modified inhibitor PTK1 was a nearly non-toxic inhibitor of p300. The present report elucidates the mechanism of acetyltransferase activity inhibition by 1,4-naphthoquinones, which involves redox cycling and nucleophilic adduct formation, and it suggests possible routes of synthesis of the non-toxic inhibitor

    Molecular and functional characterization of an evolutionarily conserved CREB-binding protein in the Lymnaea CNS

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    In eukaryotes, CREB-binding protein (CBP), a coactivator of CREB, functions both as a platform for recruiting other components of the transcriptional machinery and as a histone acetyltransferase (HAT) that alters chromatin structure. We previously showed that the transcriptional activity of cAMP-responsive element binding protein (CREB) plays a crucial role in neuronal plasticity in the pond snail Lymnaea stagnalis. However, there is no information on the molecular structure and HAT activity of CBP in the Lymnaea central nervous system (CNS), hindering an investigation of its postulated role in long-term memory (LTM). Here, we characterize the Lymnaea CBP (LymCBP) gene and identify a conserved domain of LymCBP as a functional HAT. Like CBPs of other species, LymCBP possesses functional domains, such as the KIX domain, which is essential for interaction with CREB and was shown to regulate LTM. In-situ hybridization showed that the staining patterns of LymCBP mRNA in CNS are very similar to those of Lymnaea CREB1. A particularly strong LymCBP mRNA signal was observed in the cerebral giant cell (CGC), an identified extrinsic modulatory interneuron of the feeding circuit, the key to both appetitive and aversive LTM for taste. Biochemical experiments using the recombinant protein of the LymCBP HAT domain showed that its enzymatic activity was blocked by classical HAT inhibitors. Preincubation of the CNS with such inhibitors blocked cAMP-induced synaptic facilitation between the CGC and an identified follower motoneuron of the feeding system. Taken together, our findings suggest a role for the HAT activity of LymCBP in synaptic plasticity in the feeding circuitry

    Synthesis of 2,4,6-Substituted Pyrrolo[2,3-d]pyrimidines as Potential Anticancer Agents

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    This thesis mainly focuses on the introduction of the background and work have been done in the areas of antifolates development, such as folate function, its three uptake mechanisms inside human cells, antifolates’ role in chemotherapy, et. al. In addition, the Structure-Activity-Relationship design rationale for the series of antifolates will also be discussed. Nevertheless, the details of synthesizing these pyrrolo[2,3-d]pyrimidines as potential antifolates have been described, including chemistry reviews on the pyrrolo[2,3-d]pyrimidine scaffold, and the challenges encountered and the solutions how to solve or improve in order to achieve better yield

    Emerging trends proceedings of the 17th International Conference on Theorem Proving in Higher Order Logics: TPHOLs 2004

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    technical reportThis volume constitutes the proceedings of the Emerging Trends track of the 17th International Conference on Theorem Proving in Higher Order Logics (TPHOLs 2004) held September 14-17, 2004 in Park City, Utah, USA. The TPHOLs conference covers all aspects of theorem proving in higher order logics as well as related topics in theorem proving and verification. There were 42 papers submitted to TPHOLs 2004 in the full research cate- gory, each of which was refereed by at least 3 reviewers selected by the program committee. Of these submissions, 21 were accepted for presentation at the con- ference and publication in volume 3223 of Springer?s Lecture Notes in Computer Science series. In keeping with longstanding tradition, TPHOLs 2004 also offered a venue for the presentation of work in progress, where researchers invite discussion by means of a brief introductory talk and then discuss their work at a poster session. The work-in-progress papers are held in this volume, which is published as a 2004 technical report of the School of Computing at the University of Utah

    Extracting proofs from documents

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    Often, theorem checkers like PVS are used to check an existing proof, which is part of some document. Since there is a large difference between the notations used in the documents and the notations used in the theorem checkers, it is usually a laborious task to convert an existing proof into a format which can be checked by a machine. In the system that we propose, the author is assisted in the process of converting an existing proof into the PVS language and having it checked by PVS. 1 Introduction The now-classic ALGOL 60 report [5] recognized three different levels of language: a reference language, a publication language and several hardware representations, whereby the publication language was intended to admit variations on the reference language and was to be used for stating and communicating processes. The importance of publication language ---often referred to nowadays as "pseudo-code"--- is difficult to exaggerate since a publication language is the most effective way..
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