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8 results on '"PHUs"'

1. Crystal structure of the Pseudomonas aeruginosa cytoplasmic heme binding protein, Apo-PhuS

Author

Tripathi, Sarvind, O'Neill, Maura J, Wilks, Angela, and Poulos, Thomas L

Subjects
Inorganic Chemistry, Chemical Sciences, Infectious Diseases, 2.2 Factors relating to the physical environment, 1.1 Normal biological development and functioning, Infection, Amino Acid Sequence, Bacterial Proteins, Binding Sites, Carrier Proteins, Crystallography, X-Ray, Cytoplasm, Heme-Binding Proteins, Hemeproteins, Histidine, Models, Molecular, Molecular Sequence Data, Protein Multimerization, Protein Structure, Secondary, Protein Structure, Tertiary, Pseudomonas aeruginosa, Sequence Homology, Amino Acid, PhuS, Iron, Herne, Transport, Heme, Theoretical and Computational Chemistry, Other Chemical Sciences, Inorganic & Nuclear Chemistry, Inorganic chemistry
Abstract

Iron is an essential element to all living organisms and is an important determinant of bacterial virulence. Bacteria have evolved specialized systems to sequester and transport iron from the environment or host. Pseudomonas aeruginosa, an opportunistic pathogen, uses two outer membrane receptor mediated systems (Phu and Has) to utilize host heme as a source of iron. PhuS is a 39 kDa soluble cytoplasmic heme binding protein which interacts and transports heme from the inner membrane heme transporter to the cytoplasm where it is degraded by heme oxygenase thus releasing iron. PhuS is unique among other cytoplasmic heme transporter proteins owing to the presence of three histidines in the heme binding pocket which can potentially serve as heme ligands. Out of the three histidine residues on the heme binding helix, His 209 is conserved among heme trafficking proteins while His 210 and His 212 are unique to PhuS. Here we report the crystal structure of PhuS at 1.98Å resolution which shows a unique heme binding pocket and oligomeric structure compared to other known cytoplasmic heme transporter and accounts for some of the unusual biochemical properties of PhuS.

Published
2013

2. Sustainable Non-Isocyanate Polyurethane Hot-melt Adhesives

Abstract

EN:The formation of non-isocyanate polyurethanes (NIPUs) based on polyaddition of dicyclic carbonates and diamines represents one of the most promising alternatives for replacing conventional polyurethanes which are more toxic. However, the low reactivity of five membered cyclic carbonates, even in the presence of catalysts, restricts the use of this reaction for industrial applications. One way to improve the applicability of NIPU adhesives based on 5-membered cyclic carbonates is to synthesise hot melt NIPUs. In this study, a diamine and two dicylic carbonates are combined to create sustainable hot melt NIPUs which have suitable properties to act as adhesives. The completion of the synthesis is followed by FTIR-ATR, and materials are characterised by 1H-NMR. The behaviour of the polymers is addressed by rheology measurements and the adhesive properties are evaluated on stainless steel substrates by probe tack, lap-shear tests and Shear Adhesion Failure Temperature (SAFT) as well as Shear Resistance experiments. Finally, adhesion tests on different substrates (oak wood, PMMA and HDPE) are performed., ES:la poliadición entre diaminas y carbonatos dicíclicos, es una de las alternativas más prometedoras para remplazar los poliuretanos convencionales. Sin embargo, el uso de dicha reacción para aplicaciones industriales se ve limitada por la baja reactividad de los carbonatos cíclicos de cinco miembros, incluso en presencia de catalizadores. Una manera de mejorar la utilidad de los adhesivos de poliuretano sin isocianato basados en los carbonatos cíclicos de cinco miembros, es sintetizar ashesivos hotmelt. En este estudio, se combinan una diamina y dos carbonatos dicíclicos con el fin de formar hotmelts sostenibles que contengan propiedades adecuadas para actuar como adhesivos. La reacción se sigue por FTIR-ATR y la caracterización de los materiales se lleva a cabo a través de 1H-RMN. El comportamiento de los polímeros es analizado mediante medidas reológicas. Las propiedades adhesivas son evaluadas en substratos de acero inoxidable a través de pruebas de pegajosidad (Tack), ensayos de cizallamiento (lap-shear), experimentos para medir la temperatura de falla de adherencia por cizallamiento (SAFT), y experimentos para analizar la resistencia al corte. Por último, pruebas de adhesión en diferentes substratos (madera de roble, PMMA y HDPE) son llevadas a cabo.

Published
2021

3. Sustainable Non-Isocyanate Polyurethane Hot-melt Adhesives

Abstract

EN:The formation of non-isocyanate polyurethanes (NIPUs) based on polyaddition of dicyclic carbonates and diamines represents one of the most promising alternatives for replacing conventional polyurethanes which are more toxic. However, the low reactivity of five membered cyclic carbonates, even in the presence of catalysts, restricts the use of this reaction for industrial applications. One way to improve the applicability of NIPU adhesives based on 5-membered cyclic carbonates is to synthesise hot melt NIPUs. In this study, a diamine and two dicylic carbonates are combined to create sustainable hot melt NIPUs which have suitable properties to act as adhesives. The completion of the synthesis is followed by FTIR-ATR, and materials are characterised by 1H-NMR. The behaviour of the polymers is addressed by rheology measurements and the adhesive properties are evaluated on stainless steel substrates by probe tack, lap-shear tests and Shear Adhesion Failure Temperature (SAFT) as well as Shear Resistance experiments. Finally, adhesion tests on different substrates (oak wood, PMMA and HDPE) are performed., ES:la poliadición entre diaminas y carbonatos dicíclicos, es una de las alternativas más prometedoras para remplazar los poliuretanos convencionales. Sin embargo, el uso de dicha reacción para aplicaciones industriales se ve limitada por la baja reactividad de los carbonatos cíclicos de cinco miembros, incluso en presencia de catalizadores. Una manera de mejorar la utilidad de los adhesivos de poliuretano sin isocianato basados en los carbonatos cíclicos de cinco miembros, es sintetizar ashesivos hotmelt. En este estudio, se combinan una diamina y dos carbonatos dicíclicos con el fin de formar hotmelts sostenibles que contengan propiedades adecuadas para actuar como adhesivos. La reacción se sigue por FTIR-ATR y la caracterización de los materiales se lleva a cabo a través de 1H-RMN. El comportamiento de los polímeros es analizado mediante medidas reológicas. Las propiedades adhesivas son evaluadas en substratos de acero inoxidable a través de pruebas de pegajosidad (Tack), ensayos de cizallamiento (lap-shear), experimentos para medir la temperatura de falla de adherencia por cizallamiento (SAFT), y experimentos para analizar la resistencia al corte. Por último, pruebas de adhesión en diferentes substratos (madera de roble, PMMA y HDPE) son llevadas a cabo.

Published
2021

4. Sustainable Non-Isocyanate Polyurethane Hot-melt Adhesives

Abstract

EN:The formation of non-isocyanate polyurethanes (NIPUs) based on polyaddition of dicyclic carbonates and diamines represents one of the most promising alternatives for replacing conventional polyurethanes which are more toxic. However, the low reactivity of five membered cyclic carbonates, even in the presence of catalysts, restricts the use of this reaction for industrial applications. One way to improve the applicability of NIPU adhesives based on 5-membered cyclic carbonates is to synthesise hot melt NIPUs. In this study, a diamine and two dicylic carbonates are combined to create sustainable hot melt NIPUs which have suitable properties to act as adhesives. The completion of the synthesis is followed by FTIR-ATR, and materials are characterised by 1H-NMR. The behaviour of the polymers is addressed by rheology measurements and the adhesive properties are evaluated on stainless steel substrates by probe tack, lap-shear tests and Shear Adhesion Failure Temperature (SAFT) as well as Shear Resistance experiments. Finally, adhesion tests on different substrates (oak wood, PMMA and HDPE) are performed., ES:la poliadición entre diaminas y carbonatos dicíclicos, es una de las alternativas más prometedoras para remplazar los poliuretanos convencionales. Sin embargo, el uso de dicha reacción para aplicaciones industriales se ve limitada por la baja reactividad de los carbonatos cíclicos de cinco miembros, incluso en presencia de catalizadores. Una manera de mejorar la utilidad de los adhesivos de poliuretano sin isocianato basados en los carbonatos cíclicos de cinco miembros, es sintetizar ashesivos hotmelt. En este estudio, se combinan una diamina y dos carbonatos dicíclicos con el fin de formar hotmelts sostenibles que contengan propiedades adecuadas para actuar como adhesivos. La reacción se sigue por FTIR-ATR y la caracterización de los materiales se lleva a cabo a través de 1H-RMN. El comportamiento de los polímeros es analizado mediante medidas reológicas. Las propiedades adhesivas son evaluadas en substratos de acero inoxidable a través de pruebas de pegajosidad (Tack), ensayos de cizallamiento (lap-shear), experimentos para medir la temperatura de falla de adherencia por cizallamiento (SAFT), y experimentos para analizar la resistencia al corte. Por último, pruebas de adhesión en diferentes substratos (madera de roble, PMMA y HDPE) son llevadas a cabo.

Published
2021

5. Sustainable Non-Isocyanate Polyurethane Hot-melt Adhesives

Author

Ayensa Serrano, Naroa, Sardon Muguruza, Haritz, Casado Pérez, Nerea, F. CIENCIAS QUIMICAS, KIMIKA ZIENTZIEN F., Grado en Química, and Kimikako Gradua

Subjects
NIPUs, adhesive properties, PHUs, Non-isocyanate polyurethanes, adhesives, shear, lap-shear strength, SAFT
Abstract

EN:The formation of non-isocyanate polyurethanes (NIPUs) based on polyaddition of dicyclic carbonates and diamines represents one of the most promising alternatives for replacing conventional polyurethanes which are more toxic. However, the low reactivity of five membered cyclic carbonates, even in the presence of catalysts, restricts the use of this reaction for industrial applications. One way to improve the applicability of NIPU adhesives based on 5-membered cyclic carbonates is to synthesise hot melt NIPUs. In this study, a diamine and two dicylic carbonates are combined to create sustainable hot melt NIPUs which have suitable properties to act as adhesives. The completion of the synthesis is followed by FTIR-ATR, and materials are characterised by 1H-NMR. The behaviour of the polymers is addressed by rheology measurements and the adhesive properties are evaluated on stainless steel substrates by probe tack, lap-shear tests and Shear Adhesion Failure Temperature (SAFT) as well as Shear Resistance experiments. Finally, adhesion tests on different substrates (oak wood, PMMA and HDPE) are performed. ES:la poliadición entre diaminas y carbonatos dicíclicos, es una de las alternativas más prometedoras para remplazar los poliuretanos convencionales. Sin embargo, el uso de dicha reacción para aplicaciones industriales se ve limitada por la baja reactividad de los carbonatos cíclicos de cinco miembros, incluso en presencia de catalizadores. Una manera de mejorar la utilidad de los adhesivos de poliuretano sin isocianato basados en los carbonatos cíclicos de cinco miembros, es sintetizar ashesivos hotmelt. En este estudio, se combinan una diamina y dos carbonatos dicíclicos con el fin de formar hotmelts sostenibles que contengan propiedades adecuadas para actuar como adhesivos. La reacción se sigue por FTIR-ATR y la caracterización de los materiales se lleva a cabo a través de 1H-RMN. El comportamiento de los polímeros es analizado mediante medidas reológicas. Las propiedades adhesivas son evaluadas en substratos de acero inoxidable a través de pruebas de pegajosidad (Tack), ensayos de cizallamiento (lap-shear), experimentos para medir la temperatura de falla de adherencia por cizallamiento (SAFT), y experimentos para analizar la resistencia al corte. Por último, pruebas de adhesión en diferentes substratos (madera de roble, PMMA y HDPE) son llevadas a cabo.

Published
2021

6. Ultraschall der Finger zur Beurteilung struktureller peri- und postmenopausaler Knochenveränderungen

Author

Boschitsch E, Isani R, and Szanto E

Subjects
DEXA, Knochenultraschall, Mineralstoffwechsel, BMD, lcsh:R, PHUS, lcsh:Medicine, Menopause, Ultraschall, Bone Mineral Density, Dual Energy X-ray Absorptiometry, Knochendichte, phalangeale Ultrasonographie
Abstract

Die phalangeale Ultrasonographie (PHUS) ist eines der neueren Ultraschallverfahren, die in den vergangenen Jahren zur Einschätzung des Frakturrisikos entwickelt worden sind. Basierend auf der Transmission von Ultraschallwellen durch die proximalen Phalangen der Hand werden spezifische Parameter, wie die amplitudenabhängige Schallgeschwindigkeit (amplitude dependent speed of sound, ADSOS) gemessen. In einer prospektiven offenen Studie wurde bei 338 peri- und postmenopausalen Frauen die PHUS anhand zweier für das Osteoporoserisiko bedeutender Veränderungen des Knochengewebes evaluiert und mit einer etablierten Methode zur Bestimmung der Knochendichte (bone mineral density, BMD), der dual energy X-ray absorptiometry (DEXA), in Beziehung gesetzt: Erstens wurden die vom Alter abhängigen Veränderungen und zweitens die durch eine Hormonersatztherapie (hormone replacement therapy, HRT) hervorgerufenen Effekte geprüft. Zur Beurteilung altersabhängiger Knochenveränderungen wurde ADSOS mit BMD verglichen: Beide Parameter wiesen eine negative lineare Korrelation mit dem Alter der Patientinnen auf. Diese war für ADSOS besser als für BMD. Die Sensitivität von PHUS und DEXA für den Effekt einer HRT wurde durch den Vergleich einer Gruppe substituierter Frauen mit einer Kontrollgruppe geprüft: ein signifikanter Unterschied zwischen den Gruppen war für ADSOS, nicht aber für BMD festzustellen. Die schwache Korrelation zwischen ADSOS und BMD weist darauf hin, daß mit den beiden Techniken verschiedene Eigenschaften des Knochengewebes gemessen werden. BMD ist der klassische Parameter des Mineralgehalts, ADSOS hingegen scheint in erster Linie strukturelle Eigenschaften wiederzuspiegeln. Die gegebenen Daten sollten in weiterführenden Untersuchungen dahingehend überprüft werden, ob die kombinierte Anwendung von Knochendichtemessung (DEXA) und Knochenultraschall (PHUS) die Einschätzung des Frakturrisikos verbessern kann.

Published
2000

7. From petrochemical polyurethanes to biobased polyhydroxyurethanes

Author

Zéphirin Mouloungui, Bassam Nohra, Celine Guerin, Laure Candy, Jean-François Blanco, Yann Raoul, Centre National de la Recherche Scientifique - CNRS (FRANCE), CONDAT (FRANCE), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Institut National de la Recherche Agronomique - INRA (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), ONIDOL (FRANCE), Chimie Agro-Industrielle (CAI), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole nationale supérieure des ingénieurs en arts chimiques et technologiques-Institut National de la Recherche Agronomique (INRA), Université Fédérale Toulouse Midi-Pyrénées, LGC - Laboratoire de Génie Chimique, CONDAT, Organisation Nationale Interprofessionnelle des Oléagineux (ONIDOL), and Institut National Polytechnique de Toulouse - INPT (FRANCE)

Subjects
Green chemistry, PUs, Polymers and Plastics, Biochimie, Biologie Moléculaire, PHUs, 02 engineering and technology, 010402 general chemistry, Vetegale oil, 01 natural sciences, Petrobased polyurethanes, Inorganic Chemistry, chemistry.chemical_compound, [SDV.IDA]Life Sciences [q-bio]/Food engineering, Materials Chemistry, Organic chemistry, Génie chimique, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, Polyurethane, Biobased polyhydroxyurethanes, Natural oil, Chemistry, Organic Chemistry, 021001 nanoscience & nanotechnology, Isocyanate, 0104 chemical sciences, Petrochemical, 13. Climate action, 0210 nano-technology
Abstract

International audience; From a green and sustainable chemistry standpoint, the current challenge in the polyurethane's industry is to switch from petrobased polyurethanes (PUs) to biobased polyhydroxyurethanes (PHUs). This review describes the main alternative strategies being developed with a focus on PHUs from vegetable oils and derivatives. The substitution of petrobased polyols by natural oil based polyols was the first route to biobased PUs to be developed. The second strategy involves synthesis without the need of harmful isocyanate by the nucleophilic polyaddition of polyamines to polycyclic carbonates. The technological barrier to the synthesis of biobased cyclic carbonates could be overcome by the chemical transformation of epoxidized vegetable oils or by the use of glycerine carbonate-based intermediates. New families of biobased PHUs with a lower environmental footprint could be generated.

Published
2013

8. Crystal structure of the Pseudomonas aeruginosa cytoplasmic heme binding protein, Apo-PhuS.

Author

Tripathi S, O'Neill MJ, Wilks A, and Poulos TL

Subjects
Amino Acid Sequence, Bacterial Proteins genetics, Bacterial Proteins metabolism, Binding Sites genetics, Carrier Proteins genetics, Carrier Proteins metabolism, Crystallography, X-Ray, Cytoplasm metabolism, Heme-Binding Proteins, Hemeproteins genetics, Hemeproteins metabolism, Histidine chemistry, Histidine genetics, Histidine metabolism, Models, Molecular, Molecular Sequence Data, Protein Multimerization, Protein Structure, Secondary, Pseudomonas aeruginosa genetics, Sequence Homology, Amino Acid, Bacterial Proteins chemistry, Carrier Proteins chemistry, Hemeproteins chemistry, Protein Structure, Tertiary, Pseudomonas aeruginosa metabolism
Abstract

Iron is an essential element to all living organisms and is an important determinant of bacterial virulence. Bacteria have evolved specialized systems to sequester and transport iron from the environment or host. Pseudomonas aeruginosa, an opportunistic pathogen, uses two outer membrane receptor mediated systems (Phu and Has) to utilize host heme as a source of iron. PhuS is a 39 kDa soluble cytoplasmic heme binding protein which interacts and transports heme from the inner membrane heme transporter to the cytoplasm where it is degraded by heme oxygenase thus releasing iron. PhuS is unique among other cytoplasmic heme transporter proteins owing to the presence of three histidines in the heme binding pocket which can potentially serve as heme ligands. Out of the three histidine residues on the heme binding helix, His 209 is conserved among heme trafficking proteins while His 210 and His 212 are unique to PhuS. Here we report the crystal structure of PhuS at 1.98Å resolution which shows a unique heme binding pocket and oligomeric structure compared to other known cytoplasmic heme transporter and accounts for some of the unusual biochemical properties of PhuS., (© 2013. Published by Elsevier Inc. All rights reserved.)

Published
2013
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