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  1. Article: Influence of a flame-retardant on the fire-behaviour and the residual mechanical properties of C/PEKK composite laminates exposed to a kerosene flame

    Vieille, B. / Coppalle, A. / Le Pluart, L. / Schuhler, E. / Chaudhary, A. / Rijal, B. / Alia, A. / Delpouve, N. / Bourdet, A.

    Composites. 2022 Jan., v. 152

    2022  

    Abstract: ... consolidation process from unidirectional (UD) carbon fibers (C) and a PEKK (Polyether-ketone-ketone ... additive not only delays the thermal degradation of C/PEKK laminates but also efficiently contributes ... 116 kW/m² and 1100 °C), on the composites structural integrity was examined. The changes ...

    Abstract This work examines the influence of a phosphorus-based flame-retardant additive (Exolit) on the fire-behaviour and the residual mechanical properties of composite laminates manufactured by a thermo-consolidation process from unidirectional (UD) carbon fibers (C) and a PEKK (Polyether-ketone-ketone) thermoplastic associated with or without Exolit. Depending on the laminates lay-up (orthotropic or quasi-isotropic), the influence of Exolit on the thermal degradation, resulting from a kerosene flame exposure (116 kW/m² and 1100 °C), on the composites structural integrity was examined. The changes in the residual tensile properties (axial stiffness and strength) were compared with respect to the virgin materials (experiencing no prior flame exposure) in room temperature (RT) conditions post fire exposure. The discussions on fire- and mechanically-induced damage mechanisms are supported by fractographic analysis of specimens. It is therefore possible to better understand how the fire-induced damages within the laminates micro- and meso-structures modify the mechanical behaviour of flame-exposed laminates. Thus, the axial stiffness and strength decrease moderately (−6% and −18%, respectively) in quasi-isotropic laminates with respect to virgin specimens. In orthotropic laminates, the axial stiffness decreases by 15%, whereas the axial strength dramatically decreases (−55%). The obtained results suggests that the flame-retardant additive not only delays the thermal degradation of C/PEKK laminates but also efficiently contributes to maintain the structural integrity of the composites, hence resulting in good mechanical properties. The positive effect of Exolit is particularly noticeable in orthotropic laminates whose mechanical behaviour is driven by 0° carbon fibers.
    Keywords ambient temperature ; carbon ; fire behavior ; kerosene ; thermal degradation ; thermoplastics
    Language English
    Dates of publication 2022-01
    Publishing place Elsevier Ltd
    Document type Article
    ZDB-ID 2012223-8
    ISSN 1359-835X
    ISSN 1359-835X
    DOI 10.1016/j.compositesa.2021.106720
    Database NAL-Catalogue (AGRICOLA)

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  2. Article ; Online: Malassezia pachydermatis (Weidman) C.W. Dodge.

    Cruz, Rodrigo / Vieille, Peggy

    Revista chilena de infectologia : organo oficial de la Sociedad Chilena de Infectologia

    2015  Volume 32, Issue 1, Page(s) 71–72

    Title translation Malassezia pachydermatis (Weidman) C.W. Dodge.
    MeSH term(s) Animals ; Humans ; Malassezia/genetics ; Malassezia/growth & development ; Malassezia/isolation & purification
    Language Spanish
    Publishing date 2015-02
    Publishing country Chile
    Document type Journal Article
    ZDB-ID 2048815-4
    ISSN 0717-6341 ; 0716-1018
    ISSN (online) 0717-6341
    ISSN 0716-1018
    DOI 10.4067/S0716-10182015000200014
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Malassezia pachydermatis (Weidman) C.W. Dodge

    Rodrigo Cruz / Peggy Vieille

    Revista Chilena de Infectología, Vol 32, Iss 1, Pp 71-

    2015  Volume 72

    Keywords Infectious and parasitic diseases ; RC109-216 ; Internal medicine ; RC31-1245 ; Medicine ; R
    Language Spanish
    Publishing date 2015-02-01T00:00:00Z
    Publisher Sociedad Chilena de Infectología
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Dynamics in Thermotoga neapolitana adenylate kinase: 15N relaxation and hydrogen-deuterium exchange studies of a hyperthermophilic enzyme highly active at 30 degrees C.

    Krishnamurthy, Harini / Munro, Kim / Yan, Honggao / Vieille, Claire

    Biochemistry

    2009  Volume 48, Issue 12, Page(s) 2723–2739

    Abstract: ... and inhibitor-bound form (TNAK*Ap5A) were investigated at 30 degrees C using (15)N NMR relaxation ... to those of Escherichia coli AK (ECAK) at 30 degrees C, TNAK is a unique hyperthermophilic enzyme. These catalytic properties ... states of TNAK and ECAK at 30 degrees C reveals a uniformly higher rigidity across all domains of TNAK ...

    Abstract Backbone conformational dynamics of Thermotoga neapolitana adenylate kinase in the free form (TNAK) and inhibitor-bound form (TNAK*Ap5A) were investigated at 30 degrees C using (15)N NMR relaxation measurements and NMR monitored hydrogen-deuterium exchange. With kinetic parameters identical to those of Escherichia coli AK (ECAK) at 30 degrees C, TNAK is a unique hyperthermophilic enzyme. These catalytic properties make TNAK an interesting and novel model to study the interplay between protein rigidity, stability, and activity. Comparison of fast time scale dynamics (picosecond to nanosecond) in the open and closed states of TNAK and ECAK at 30 degrees C reveals a uniformly higher rigidity across all domains of TNAK. Within this framework of a rigid TNAK structure, several residues located in the AMP-binding domain and in the core-lid hinge regions display high picosecond to nanosecond time scale flexibility. Together with the recent comparison of ECAK dynamics with those of hyperthermophilic Aquifex aeolicus AK (AAAK), our results provide strong evidence for the role of picosecond to nanosecond time scale fluctuations in both stability and activity. In the slow time scales, TNAK's increased rigidity is not uniform but localized in the AMP-binding and lid domains. The core domain amides of ECAK and TNAK in the open and closed states show comparable protection against exchange. Significantly, the hinges framing the lid domain show similar exchange data in ECAK and TNAK open and closed forms. Our NMR relaxation and hydrogen-deuterium exchange studies therefore suggest that TNAK maintains high activity at 30 degrees C by localizing flexibility to the hinge regions that are key to facilitating conformational changes.
    MeSH term(s) Adenylate Kinase/chemistry ; Amino Acid Sequence ; Bacterial Proteins/chemistry ; Deuterium Exchange Measurement ; Models, Biological ; Molecular Sequence Data ; Nuclear Magnetic Resonance, Biomolecular ; Sequence Alignment ; Temperature ; Thermotoga neapolitana/enzymology
    Chemical Substances Bacterial Proteins ; Adenylate Kinase (EC 2.7.4.3)
    Language English
    Publishing date 2009-03-31
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1108-3
    ISSN 1520-4995 ; 0006-2960
    ISSN (online) 1520-4995
    ISSN 0006-2960
    DOI 10.1021/bi802001w
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article: Thermotoga neapolitana adenylate kinase is highly active at 30 degrees C.

    Vieille, Claire / Krishnamurthy, Harini / Hyun, Hyung-Hwan / Savchenko, Alexei / Yan, Honggao / Zeikus, J Gregory

    The Biochemical journal

    2003  Volume 372, Issue Pt 2, Page(s) 577–585

    Abstract: ... 2+)/mol of recombinant TNAK. The EDTA-treated enzyme has a melting temperature (T (m)=93.5 degrees C ... 6.2 degrees C below that of the holoenzyme (99.7 degrees C), identifying Zn(2+) as a stabilizing ... and K (m) values at 30 degrees C identical with those of the E. coli AK at 30 degrees C, and displays ...

    Abstract The adenylate kinase (AK) gene from Thermotoga neapolitana, a hyperthermophilic bacterium, was cloned and overexpressed in Escherichia coli, and the recombinant enzyme was biochemically characterized. The T. neapolitana AK (TNAK) sequence indicates that this enzyme belongs to the long bacterial AKs. TNAK contains the four cysteine residues that bind Zn(2+) in all Gram-positive AKs and in a few other Zn(2+)-containing bacterial AKs. Atomic emission spectroscopy and titration data indicate a content of 1 mol of Zn(2+)/mol of recombinant TNAK. The EDTA-treated enzyme has a melting temperature (T (m)=93.5 degrees C) 6.2 degrees C below that of the holoenzyme (99.7 degrees C), identifying Zn(2+) as a stabilizing feature in TNAK. TNAK is a monomeric enzyme with a molecular mass of approx. 25 kDa. TNAK displays V (max) and K (m) values at 30 degrees C identical with those of the E. coli AK at 30 degrees C, and displays very high activity at 80 degrees C, with a specific activity above 8000 units/mg. The unusually high activity of TNAK at 30 degrees C makes it an interesting model to test the role of enzyme flexibility in activity.
    MeSH term(s) Adenylate Kinase/chemistry ; Adenylate Kinase/genetics ; Adenylate Kinase/metabolism ; Amino Acid Sequence ; Apoenzymes ; Bacterial Proteins/chemistry ; Bacterial Proteins/metabolism ; Circular Dichroism ; Cloning, Molecular ; DNA, Bacterial/genetics ; DNA, Bacterial/metabolism ; Enzyme Stability ; Escherichia coli/genetics ; Escherichia coli/metabolism ; Gram-Negative Anaerobic Straight, Curved, and Helical Rods/enzymology ; Gram-Negative Anaerobic Straight, Curved, and Helical Rods/genetics ; Hot Temperature ; Hydrogen-Ion Concentration ; Kinetics ; Molecular Sequence Data ; Protein Folding ; Sequence Homology, Amino Acid ; Spectrophotometry ; Zinc/chemistry ; Zinc/metabolism
    Chemical Substances Apoenzymes ; Bacterial Proteins ; DNA, Bacterial ; Adenylate Kinase (EC 2.7.4.3) ; Zinc (J41CSQ7QDS)
    Language English
    Publishing date 2003-06-01
    Publishing country England
    Document type Comparative Study ; Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 2969-5
    ISSN 1470-8728 ; 0264-6021 ; 0006-2936 ; 0306-3275
    ISSN (online) 1470-8728
    ISSN 0264-6021 ; 0006-2936 ; 0306-3275
    DOI 10.1042/BJ20021377
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Secondary Alcohol Dehydrogenases from Thermoanaerobacter pseudoethanolicus and Thermoanaerobacter brockii as Robust Catalysts.

    Musa, Musa M / Vieille, Claire / Phillips, Robert S

    Chembiochem : a European journal of chemical biology

    2021  Volume 22, Issue 11, Page(s) 1884–1893

    Abstract: Alcohol dehydrogenases (ADHs) are an important type of enzyme that have significant applications as biocatalysts. Secondary ADHs from Thermoanaerobacter pseudoethanolicus (TeSADH) and Thermoanaerobacter brockii (TbSADH) are well-known as robust catalysts. ...

    Abstract Alcohol dehydrogenases (ADHs) are an important type of enzyme that have significant applications as biocatalysts. Secondary ADHs from Thermoanaerobacter pseudoethanolicus (TeSADH) and Thermoanaerobacter brockii (TbSADH) are well-known as robust catalysts. However, like most other ADHs, these enzymes suffer from their high substrate specificities (i. e., limited substrate scope), which to some extent restricts their use as biocatalysts. This minireview discusses recent efforts to expand the substrate scope and tune the enantioselectivity of TeSADH and TbSADH by using site-directed mutagenesis and directed evolution. Various examples of asymmetric synthesis of optically active alcohols using both enzymes are highlighted. Moreover, the unique thermal stability and organic solvent tolerance of these enzymes is illustrated by their concurrent inclusion with other interesting reactions to synthesize optically active alcohols and amines. For instance, TeSADH has been used in quantitative non-stereoselective oxidation of alcohols to deracemize alcohols via cyclic deracemization and in the racemization of enantiopure alcohols to accomplish a bienzymatic dynamic kinetic resolution.
    MeSH term(s) Alcohol Dehydrogenase/genetics ; Alcohol Dehydrogenase/metabolism ; Alcohols/chemistry ; Alcohols/metabolism ; Biocatalysis ; Molecular Structure ; Mutagenesis, Site-Directed ; Thermoanaerobacter/enzymology
    Chemical Substances Alcohols ; Alcohol Dehydrogenase (EC 1.1.1.1)
    Language English
    Publishing date 2021-04-08
    Publishing country Germany
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 2020469-3
    ISSN 1439-7633 ; 1439-4227
    ISSN (online) 1439-7633
    ISSN 1439-4227
    DOI 10.1002/cbic.202100043
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article: Experimental and Finite Element Analysis of the Tensile Behavior of Architectured Cu-Al Composite Wires.

    Dashti, Alireza / Keller, Clément / Vieille, Benoit / Guillet, Alain / Bouvet, Christophe

    Materials (Basel, Switzerland)

    2021  Volume 14, Issue 21

    Abstract: The present study investigates, experimentally and numerically, the tensile behavior of copper-clad aluminum composite wires. Two fiber-matrix configurations, the conventional Al-core/Cu-case and a so-called architectured wire with a continuous copper ... ...

    Abstract The present study investigates, experimentally and numerically, the tensile behavior of copper-clad aluminum composite wires. Two fiber-matrix configurations, the conventional Al-core/Cu-case and a so-called architectured wire with a continuous copper network across the cross-section, were considered. Two different fiber arrangements with 61 or 22 aluminum fibers were employed for the architectured samples. Experimentally, tensile tests on the two types of composites show that the flow stress of architectured configurations is markedly higher than that of the linear rule of mixtures' prediction. Transverse stress components and processing-induced residual stresses are then studied via numerical simulations to assess their potential effect on this enhanced strength. A set of elastic-domain and elastoplastic simulations were performed to account for the influence of Young's modulus and volume fraction of each phase on the magnitude of transverse stresses and how theses stresses contribute to the axial stress-strain behavior. Besides, residual stress fields of different magnitude with literature-based distributions expected for cold-drawn wires were defined. The findings suggest that the improved yield strength of architectured Cu-Al wires cannot be attributed to the weak transverse stresses developed during tensile testing, while there are compelling implications regarding the strengthening effect originating from the residual stress profile. Finally, the results are discussed and concluded with a focus on the role of architecture and residual stresses.
    Language English
    Publishing date 2021-10-22
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2487261-1
    ISSN 1996-1944
    ISSN 1996-1944
    DOI 10.3390/ma14216305
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Sensibilidad in vitro de cepas chilenas de Cryptococcus neoformans de origen clínico.

    Cruz Ch, Rodrigo / Vieille O, Peggy / Stojanova, Jana

    Revista chilena de infectologia : organo oficial de la Sociedad Chilena de Infectologia

    2020  Volume 37, Issue 2, Page(s) 124–128

    Abstract: ... drug sensitivity strips (MIC Test Strips).: Results: All strains corresponded to C. neoformans ...

    Title translation In vitro susceptibility of Chilean Cryptococcus neoformans strains of clinical source.
    Abstract Background: Cryptococcus yeast infections primarily affect immunocompromised patients. There have been few susceptibility studies conducted for this genus in Chile.
    Aims: To determine the in vitro susceptibility to commonly used antifungals and evaluate the concordance between susceptibility determined by microdilution in broth and commercially available strips.
    Methods: Descriptive study of 21 Cryptococcus strains, isolated from cerebrospinal fluid and blood. The MIC50 and MIC90 for fluconazole, voriconazole and amphotericin B was determined by broth microdilution (Sensititre Yeast One®) and by commercial drug sensitivity strips (MIC Test Strips).
    Results: All strains corresponded to C. neoformans. The ranges of MIC50 and MIC90 for each antifungal studied were wide by both methods. The essential agreement between Sensititre Yeast One test and strips was 24, 62 and 29% for fluconazole, voriconazole and amphotericin B, respectively.
    Conclusions: The Sensititre Yeast One test and MIC Test Strips exhibited poor essential concordance, especially for fluconazole and amphotericin B.
    MeSH term(s) Antifungal Agents ; Chile ; Cryptococcosis ; Cryptococcus neoformans ; Fluconazole ; Humans ; Microbial Sensitivity Tests
    Chemical Substances Antifungal Agents ; Fluconazole (8VZV102JFY)
    Language Spanish
    Publishing date 2020-07-31
    Publishing country Chile
    Document type Journal Article
    ZDB-ID 2048815-4
    ISSN 0717-6341 ; 0716-1018
    ISSN (online) 0717-6341
    ISSN 0716-1018
    DOI 10.4067/s0716-10182020000200124
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Escherichia coli endocarditis in an hemodialysis patient.

    Vieille, T / Winiszewski, H / Chirouze, C / Bertrand, X / Fournier, D

    Medecine et maladies infectieuses

    2019  Volume 49, Issue 6, Page(s) 478–479

    MeSH term(s) Aged ; Endocarditis, Bacterial/complications ; Endocarditis, Bacterial/diagnosis ; Escherichia coli Infections/complications ; Escherichia coli Infections/diagnosis ; Female ; Humans ; Radiation Injuries/complications ; Radiation Injuries/microbiology ; Rectal Diseases/etiology ; Renal Dialysis/adverse effects ; Renal Insufficiency, Chronic/etiology ; Renal Insufficiency, Chronic/microbiology ; Renal Insufficiency, Chronic/therapy ; Uterine Neoplasms/radiotherapy
    Language English
    Publishing date 2019-03-27
    Publishing country France
    Document type Case Reports ; Letter
    ZDB-ID 423536-8
    ISSN 1769-6690 ; 0399-077X ; 1166-8237
    ISSN (online) 1769-6690
    ISSN 0399-077X ; 1166-8237
    DOI 10.1016/j.medmal.2019.03.004
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article ; Online: Designed Ankyrin Repeat Proteins provide insights into the structure and function of CagI and are potent inhibitors of CagA translocation by the Helicobacter pylori type IV secretion system.

    Blanc, Marine / Lettl, Clara / Guérin, Jérémy / Vieille, Anaïs / Furler, Sven / Briand-Schumacher, Sylvie / Dreier, Birgit / Bergé, Célia / Plückthun, Andreas / Vadon-Le Goff, Sandrine / Fronzes, Rémi / Rousselle, Patricia / Fischer, Wolfgang / Terradot, Laurent

    PLoS pathogens

    2023  Volume 19, Issue 5, Page(s) e1011368

    Abstract: ... domains (CagIN) prolonged by globular C-terminal domains (CagIC). Three Designed Ankyrin Repeat Proteins ...

    Abstract The bacterial human pathogen Helicobacter pylori produces a type IV secretion system (cagT4SS) to inject the oncoprotein CagA into gastric cells. The cagT4SS external pilus mediates attachment of the apparatus to the target cell and the delivery of CagA. While the composition of the pilus is unclear, CagI is present at the surface of the bacterium and required for pilus formation. Here, we have investigated the properties of CagI by an integrative structural biology approach. Using Alpha Fold 2 and Small Angle X-ray scattering, it was found that CagI forms elongated dimers mediated by rod-shape N-terminal domains (CagIN) prolonged by globular C-terminal domains (CagIC). Three Designed Ankyrin Repeat Proteins (DARPins) K2, K5 and K8 selected against CagI interacted with CagIC with subnanomolar affinities. The crystal structures of the CagI:K2 and CagI:K5 complexes were solved and identified the interfaces between the molecules, thereby providing a structural explanation for the difference in affinity between the two binders. Purified CagI and CagIC were found to interact with adenocarcinoma gastric (AGS) cells, induced cell spreading and the interaction was inhibited by K2. The same DARPin inhibited CagA translocation by up to 65% in AGS cells while inhibition levels were 40% and 30% with K8 and K5, respectively. Our study suggests that CagIC plays a key role in cagT4SS-mediated CagA translocation and that DARPins targeting CagI represent potent inhibitors of the cagT4SS, a crucial risk factor for gastric cancer development.
    MeSH term(s) Humans ; Bacterial Proteins/metabolism ; Antigens, Bacterial/metabolism ; Type IV Secretion Systems/genetics ; Type IV Secretion Systems/metabolism ; Designed Ankyrin Repeat Proteins ; Helicobacter pylori/metabolism ; Helicobacter Infections/microbiology
    Chemical Substances Bacterial Proteins ; Antigens, Bacterial ; Type IV Secretion Systems ; Designed Ankyrin Repeat Proteins
    Language English
    Publishing date 2023-05-08
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2205412-1
    ISSN 1553-7374 ; 1553-7374
    ISSN (online) 1553-7374
    ISSN 1553-7374
    DOI 10.1371/journal.ppat.1011368
    Database MEDical Literature Analysis and Retrieval System OnLINE

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