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1,575 results on '"Douglas, R. G."'

2. Confluent operator algebras and the closability property

Author

Bercovici, H., Douglas, R. G., Foias, C., and Pearcy, C.

Subjects
Mathematics - Functional Analysis, Mathematics - Operator Algebras, 47L10, 47A45, 47L40
Abstract

Certain operator algebras A on a Hilbert space have the property that every densely defined linear transformation commuting with A is closable. Such algebras are said to have the closability property. They are important in the study of the transitive algebra problem. More precisely, if A is a two-transitive algebra with the closability property, then A is dense in the algebra of all bounded operators, in the weak operator topology. In this paper we focus on algebras generated by a completely nonunitary contraction, and produce several new classes of algebras with the closability property. We show that this property follows from a certain strict cyclicity property, and we give very detailed information on the class of completely nonunitary contractions satisfying this property, as well as a stronger property which we call confluence., Comment: Preliminary version

Published
2009

4. Bi-isometries and commutant lifting

Author

Bercovici, H., Douglas, R. G., and Foias, C.

Subjects
Mathematics - Spectral Theory, Mathematics - Functional Analysis, 47A20, 47A15
Abstract

A new functional model for pairs of commuting isometries is described. Intertwining operators between such models are then studied in order to approach the classification of invariant subspaces of such pairs., Comment: 31 pages

Published
2008

5. On the clssification of multi-isometries

Author

Bercovici, H., Douglas, R. G., and Foias, C.

Subjects
Mathematics - Functional Analysis, 47A45
Abstract

We consider the classification, up to unitary equivalence, of commuting n-tuples of isometries. We pay special attention to the case when the product of the isometries is a shift of finite multiplicity, and we provide a complete classification when this multiplicity equals n. When n=2, we identify a pivotal operator which captures many of the properties of a bi-isometry., Comment: 17 pages

Published
2006

10. Canonical Models for Bi-isometries

Author

Bercovici, H., Douglas, R. G., Foias, C., Dym, Harry, editor, Kaashoek, Marinus A., editor, Lancaster, Peter, editor, Langer, Heinz, editor, and Lerer, Leonid, editor

Published
2012
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11. The EUFOREA pocket guide for chronic rhinosinusitis.

Author

Hellings, P. W., Fokkens, W. J., Orlandi, R., Adriaensen, G. F., Alobid, I., Baroody, F. M., Bjermer, L., Senior, B. A., Cervin, A., Cohen, N. A., Constantinidis, J., De Corso, E., Desrosiers, M., Diamant, Z., Douglas, R. G., Gane, S., Gevaert, P., Han, J. K., Harvey, R. J., and Hopkins, C.

Published
2023
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23. European Position Paper on Rhinosinusitis and Nasal Polyps 2020

Author

Fokkens, W J, Lund, V J, Hopkins, C, Hellings, P W, Kern, R, Reitsma, S, Toppila-Salmi, S, Bernal-Sprekelsen, M, Mullol, J, Alobid, I, Terezinha Anselmo-Lima, W, Bachert, C, Baroody, F, von Buchwald, C, Cervin, A, Cohen, N, Constantinidis, J, De Gabory, L, Desrosiers, M, Diamant, Z, Douglas, R G, Gevaert, P H, Hafner, A, Harvey, R J, Joos, G F, Kalogjera, L, Knill, A, Kocks, J H, Landis, B N, Limpens, J, Lebeer, S, Lourenco, O, Meco, C, Matricardi, P M, O'Mahony, L, Philpott, C M, Ryan, D, Schlosser, R, Senior, B, Smith, T L, Teeling, T, Tomazic, P V, Wang, D, Zhang, L, Agius, A M, Ahlstrom-Emanuelsson, C, Alabri, R, Albu, S, Alhabash, S, Aleksic, A, Aloulah, M, Al-Qudah, M, Alsaleh, S, Baban, M A, Baudoin, T, Balvers, T, Battaglia, P, Bedoya, J D, Beule, A, Bofares, K M, Braverman, I, Brozek-Madry, E, Richard, B, Callejas, C, Carrie, S, Caulley, L, Chussi, D, de Corso, E, Coste, A, El Hadi, U, Elfarouk, A, Eloy, P H, Farrokhi, S, Felisati, G, Ferrari, M D, Fishchuk, R, Grayson, W, Goncalves, P M, Grdinic, B, Grgic, V, Hamizan, A W, Heinichen, J V, Husain, S, Ping, T I, Ivaska, J, Jakimovska, F, Jovancevic, L, Kakande, E, Kamel, R, Karpischenko, S, Kariyawasam, H H, Kawauchi, H, Kjeldsen, A, Klimek, L, Krzeski, A, Kopacheva Barsova, G, Kim, S W, Lal, D, Letort, J J, Lopatin, A, Mahdjoubi, A, Mesbahi, A, Netkovski, J, Nyenbue Tshipukane, D, Obando-Valverde, A, Okano, M, Onerci, M, Ong, Y K, Orlandi, R, Otori, N, Ouennoughy, K, Ozkan, M, Peric, A, Plzak, J, Prokopakis, E, Prepageran, N, Psaltis, A, Pugin, B, Raftopulos, M, Rombaux, P, Riechelmann, H, Sahtout, S, Sarafoleanu, C-C, Searyoh, K, Rhee, C-S, Shi, J, Shkoukani, M, Shukuryan, A K, Sicak, M, Smyth, D, Sindvongs, K, Soklic Kosak, T, Stjarne, P, Sutikno, B, Steinsvag, S, Tantilipikorn, P, Thanaviratananich, S, Tran, T, Urbancic, J, Valiulius, A, Vasquez de Aparicio, C, Vicheva, D, Virkkula, P M, Vicente, G, Voegels, R, Wagenmann, M M, Wardani, R S, Welge-Lussen, A, Witterick, I, Wright, E, Zabolotniy, D, Zsolt, B, Zwetsloot, C P, Fokkens, W J, Lund, V J, Hopkins, C, Hellings, P W, Kern, R, Reitsma, S, Toppila-Salmi, S, Bernal-Sprekelsen, M, Mullol, J, Alobid, I, Terezinha Anselmo-Lima, W, Bachert, C, Baroody, F, von Buchwald, C, Cervin, A, Cohen, N, Constantinidis, J, De Gabory, L, Desrosiers, M, Diamant, Z, Douglas, R G, Gevaert, P H, Hafner, A, Harvey, R J, Joos, G F, Kalogjera, L, Knill, A, Kocks, J H, Landis, B N, Limpens, J, Lebeer, S, Lourenco, O, Meco, C, Matricardi, P M, O'Mahony, L, Philpott, C M, Ryan, D, Schlosser, R, Senior, B, Smith, T L, Teeling, T, Tomazic, P V, Wang, D, Zhang, L, Agius, A M, Ahlstrom-Emanuelsson, C, Alabri, R, Albu, S, Alhabash, S, Aleksic, A, Aloulah, M, Al-Qudah, M, Alsaleh, S, Baban, M A, Baudoin, T, Balvers, T, Battaglia, P, Bedoya, J D, Beule, A, Bofares, K M, Braverman, I, Brozek-Madry, E, Richard, B, Callejas, C, Carrie, S, Caulley, L, Chussi, D, de Corso, E, Coste, A, El Hadi, U, Elfarouk, A, Eloy, P H, Farrokhi, S, Felisati, G, Ferrari, M D, Fishchuk, R, Grayson, W, Goncalves, P M, Grdinic, B, Grgic, V, Hamizan, A W, Heinichen, J V, Husain, S, Ping, T I, Ivaska, J, Jakimovska, F, Jovancevic, L, Kakande, E, Kamel, R, Karpischenko, S, Kariyawasam, H H, Kawauchi, H, Kjeldsen, A, Klimek, L, Krzeski, A, Kopacheva Barsova, G, Kim, S W, Lal, D, Letort, J J, Lopatin, A, Mahdjoubi, A, Mesbahi, A, Netkovski, J, Nyenbue Tshipukane, D, Obando-Valverde, A, Okano, M, Onerci, M, Ong, Y K, Orlandi, R, Otori, N, Ouennoughy, K, Ozkan, M, Peric, A, Plzak, J, Prokopakis, E, Prepageran, N, Psaltis, A, Pugin, B, Raftopulos, M, Rombaux, P, Riechelmann, H, Sahtout, S, Sarafoleanu, C-C, Searyoh, K, Rhee, C-S, Shi, J, Shkoukani, M, Shukuryan, A K, Sicak, M, Smyth, D, Sindvongs, K, Soklic Kosak, T, Stjarne, P, Sutikno, B, Steinsvag, S, Tantilipikorn, P, Thanaviratananich, S, Tran, T, Urbancic, J, Valiulius, A, Vasquez de Aparicio, C, Vicheva, D, Virkkula, P M, Vicente, G, Voegels, R, Wagenmann, M M, Wardani, R S, Welge-Lussen, A, Witterick, I, Wright, E, Zabolotniy, D, Zsolt, B, and Zwetsloot, C P

Abstract

The European Position Paper on Rhinosinusitis and Nasal Polyps 2020 is the update of similar evidence based position papers published in 2005 and 2007 and 2012. The core objective of the EPOS2020 guideline is to provide revised, up-to-date and clear evidence-based recommendations and integrated care pathways in ARS and CRS. EPOS2020 provides an update on the literature published and studies undertaken in the eight years since the EPOS2012 position paper was published and addresses areas not extensively covered in EPOS2012 such as paediatric CRS and sinus surgery. EPOS2020 also involves new stakeholders, including pharmacists and patients, and addresses new target users who have become more involved in the management and treatment of rhinosinusitis since the publication of the last EPOS document, including pharmacists, nurses, specialised care givers and indeed patients themselves, who employ increasing self-management of their condition using over the counter treatments. The document provides suggestions for future research in this area and offers updated guidance for definitions and outcome measurements in research in different settings. EPOS2020 contains chapters on definitions and classification where we have defined a large number of terms and indicated preferred terms. A new classification of CRS into primary and secondary CRS and further division into localized and diffuse disease, based on anatomic distribution is proposed. There are extensive chapters on epidemiology and predisposing factors, inflammatory mechanisms, (differential) diagnosis of facial pain, allergic rhinitis, genetics, cystic fibrosis, aspirin exacerbated respiratory disease, immunodeficiencies, allergic fungal rhinosinusitis and the relationship between upper and lower airways. The chapters on paediatric acute and chronic rhinosinusitis are totally rewritten. All available evidence for the management of acute rhinosinusitis and chronic rhinosinusitis with or without nasal polyps in adult

Published
2020

35. Thymine-functionalised siloxanes: Model compounds and polymers

Author

Kieran C. Molloy, Rhys D. Short, Douglas R. G. Smith, Gabriele Kociok-Köhn, and Gareth J. Price

Subjects
Hydrogen bonding, chemistry.chemical_classification, Siloxane, Hydrogen bond, Organic Chemistry, Polymer, Condensation reaction, Biochemistry, Nucleobase, Thymine, Inorganic Chemistry, chemistry.chemical_compound, Silicone, chemistry, Polymer chemistry, Materials Chemistry, Surface modification, Organic chemistry, Physical and Theoretical Chemistry
Abstract

A novel, efficient synthetic method for the production of organosiloxane polymers functionalised with pendant DNA bases, typified by thymine, is reported. A condensation reaction between an α-amino-ω-alkylsilane or an amino-functionalised siloxane with aldehyde-functionalised thymine gave polymers in higher overall yields than the methods previously reported. Variation in the loading of thymine led to a range of material properties from a highly viscous fluid at 0.2% functionalization to a hard, brittle solid at 20% loading due to hydrogen bonding interactions.

Published
2015

38. On Moduli for Invariant Subspaces

Author

Cowen, M. J., Douglas, R. G., Gohberg, I., editor, Apostol, C., editor, Douglas, R. G., editor, Sz.-Nagy, B., editor, Voiculescu, D., editor, and Arsene, Gr., editor

Published
1982
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39. The Structures of Uncommon CationicN-alkenyl Purine and Pyrimidine Bases

Author

Kieran C. Molloy, Gareth J. Price, Douglas R. G. Smith, and Gabriele Kociok-Köhn

Subjects
Purine, Pyrimidine, 010405 organic chemistry, Hydrogen bond, Organic Chemistry, Cationic polymerization, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Ion, chemistry.chemical_compound, chemistry, Bromide, Polymer chemistry, Organic chemistry, Water of crystallization, Hydrate
Abstract

The structures of 1,3 bis-(allyl)cytosinium bromide (1), 7,9 bis-(allyl)adeninium bromide hydrate (2) and 3-(butenyl)adeninium bromide (3) have been determined. 1 is dimeric via N-H...Br hydrogen bonds, which further associate into ribbons via weaker C-H...Br interactions. 2 is also dimeric, now from N-H...N hydrogen bonds, which build up further through a complex array of hydrogen bonds involving both the anion and water of crystallization (O-H...N, O-H...Br, C-H...Br). 3 does not dimerise but forms polymeric sheets via a series of N-H...N, C-H...N and C-H...Br hydrogen bonds.

Published
2014

40. Reducing the safety risk of low nitrite restructured sliced cooked ham by gamma radiation.

Author

Silva, Douglas R. G., Moura, Ana Paula R., Haddad, Gabriela B. S., Souza, Poliana M., Ramos, Alcinéia L. S., Hopkins, David L., and Ramos, Eduardo M.

Subjects
*GAMMA rays, *LISTERIA monocytogenes, *HAM, *NITRITES, *FOOD safety, *SODIUM nitrites
Abstract

This study evaluated the effects of low doses of gamma radiation (up to 2.0 kGy) on the survival and growth of Listeria monocytogenes and on technological characteristics of RTE cooked hams, formulated without and with 50 and 150 mg/kg of sodium nitrite, after 30 days of cold (4°C) storage. The radiation reduced from 0.33 kGy in uncured and RTE50 to 0.25 kGy in RTE150 and after storage, a reduction (p >.05) in the Listeria growth in the cured samples. Irradiation had no effect (p >.05) on the pH, water activity, residual nitrite, lipid oxidation, or CIELCH color indices of RTE hams, regardless of the nitrite content. Higher TBARS values, chroma, and hue angle were observed (p <.05) in uncured samples than in cured ones. The RTE50 with irradiation by 1.0 to 2.0 kGy can be used to ensure the Listeria safety. Practical applications: Meat RTE products post‐thermal manipulation, like in slicing operations, may result in an enhanced microbial risk, especially regard to Listeria postprocessing contamination. Therefore, post‐lethality treatments like gamma irradiation are of interest to the industry to ensure food safety. Combining the lower doses of irradiation with low nitrite content in RTE meats could be used to guarantee microbial safety, minimizing irradiation‐induced quality changes, and contributing to the sensory and technological characteristics of the products. [ABSTRACT FROM AUTHOR]

Published
2021
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41. Biomimetic polyorganosiloxanes: model compounds for new materials

Author

Gabriele Kociok-Köhn, Kieran C. Molloy, Douglas R. G. Smith, Timothy J. Prior, Mary F. Mahon, and Gareth J. Price

Subjects
Models, Molecular, Siloxanes, Stereochemistry, Hydrosilylation, Adenine, Dithiobiuret, Imine, New materials, Medicinal chemistry, Adduct, Thymine, Inorganic Chemistry, Cytosine, chemistry.chemical_compound, chemistry, Biomimetic Materials, Biomimetics, Preliminary report
Abstract

The chemistry of N-organosilylalkyl-substituted heterocyclic bases (thymine, adenine and cytosine) is described, covering the structures of model compounds, the synthesis of substituted oligo-siloxanes and a preliminary report of the synthesis of a poly(organosiloxane) with pendant N-alkyl(heterocycle) functionalities. N-Alkenylthymines CH2[double bond, length as m-dash]CH(CH2)nT (T = thymine, n = 1 (1), 2 (2), 3 (3)) have been prepared and 2 hydrosilylated to form PhMe2Si(CH2)4T (5). Alternatively, 5 was prepared by reaction of PhMe2Si(CH2)4Br (6) with (O,O-SiMe3)2T, a method which has also been used to prepare PhMe2Si(CH2)4A (7) and PhMe2Si(CH2)4C (8) (A = adenine, C = cytosine). Model di- and tri-siloxanes [Br(CH2)4(Me)2Si]2O (10), Me3SiOSi(Me)2(CH2)4Br (11), PhMe2SiOSi(Me)2(CH2)4Br (12) and (Me3SiO)2(Me)Si(CH2)4Br (13) have been prepared by hydrosilylation of H2C[double bond, length as m-dash]C(H)(CH2)4Br with an appropriate hydrosiloxane and used to prepare Me3SiO(Me)2Si(CH2)4T (14), Me3SiO(Me)2Si(CH2)4A (15) (both from 11), and (Me3SiO)2(Me)Si(CH2)4T (16), (Me3SiO)2(Me)Si(CH2)4A (17) (both from 13). 10 reacts with thymine to give a mixture of the pyrimidocyclophane cyclo-T-N,N-[(CH2)4(Me)2Si]2O (19) and [T(CH2)4Si(Me)2]2O (20), while cytosine reacts similarly to form cyclo-C-N,N-[(CH2)4(Me)2Si]2O (21; as an imine) and [C(CH2)4Si(Me)2]2O (22); adenine only generates [A(CH2)4Si(Me)2]2O (18) in an analogous synthesis. Using a related protocol, polymeric {[MeSi(O)(CH2)4Br]2[Me2SiO]98}n (23) has been converted to {[MeSi(O)(CH2)4T]2[Me2SiO]98}n (24) and {[MeSi(O)(CH2)4A]2[Me2SiO]98}n (25). The structures of 4, 5, 8, 19 and 21, along with a 2 : 1 adduct of 5 with Ni(dithiobiuret)2 (9) are reported.

Published
2014

46. CORRESPONDENCE

Author

Douglas, R. G. and Youngblood, Curtis T.

Published
1976

50. Hankel and toeplitz operators

Author

Adamyan, V. M., Arov, D. Z., Krein, M. G., Power, S. C., Axler, Sheldon, Clark, Douglas N., Peller, V. V., Douglas, R. G., Sundberg, Carl, Krupnik, N.Ya., Verbitsky, I.È, Karlovich, Yu. I., Spitkovskii, I. M., Coburn, L. A., Vladimirov, V. S., Volovich, I. V., Silbermann, B., Prössdorf, S., Latushkin, Yu. D., Litvinchuk, G. S., Semënov-Tian-Shansky, M. A., Havin, Victor P., editor, Hruščëv, Sergei V., editor, and Nikol'skii, Nikolai K., editor

Published
1984
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