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1. Selective Skeletal Butene Isomerization Through a Bimolecular Mechanism Isomérisation bimoléculaire sélective du n-butène en isobutène

Author

Benazzi E., Travers C., Gnep N. S., Andy P., and Guisnet M.

Subjects
Chemical technology, TP1-1185, Energy industries. Energy policy. Fuel trade, HD9502-9502.5
Abstract

n-Butene transformation was carried out at 350°C over medium pore size zeolites (H-FER, H-TON, H-EU-1 and H-MFI) and at 500°C over alumina. With fresh catalysts, not only isobutene but also propene and pentenes are primary products, which indicates that at least some of the butene isomerization occurs through oligomerization-isomerization-cracking steps (bimolecular mechanism). The large differences in selectivity are due to many factors, including whether or not trimer intermediates participate in the mechanism and limited product desorption. All the catalysts exhibit increasing isobutene selectivity with increasing time on-stream. This increase in selectivity can be explained by the selective isomerization of n-butene through a reaction process whose first step is the formation of trimethylpentene intermediates from isobutene product and n-butene reactant. This autocatalytic reaction can render the bimolecular transformation of n-butenes very selective to isobutene. La transformation du n-butène a été étudiée en réacteur dynamique à 350°C sur des zéolithes à taille de pore intermédiaire (H-FER, H-TON, H-EU-1 et H-MFI) et à 500°C sur alumine. Sur les catalyseurs frais, l'isobutène mais aussi le propène et les pentènes sont directement formés (produits primaires), ce qui démontre que l'isomérisation de squelette du n-butène se produit au moins en partie par des étapes successives d'oligomérisation, isomérisation et craquage (mécanisme bimoléculaire). Les différences importantes de sélectivité entre les catalyseurs sont dues à de nombreux facteurs : participation ou non d'intermédiaires trimères, limitations dans la désorption des produits branchés, etc. Sur tous les catalyseurs, la sélectivité en isobutène augmente avec le temps de travail. Cette augmentation s'explique par un nouveau mode d'isomérisation très sélectif impliquant comme intermédiaires des triméthylpentènes formés par réaction du n-butène sur des molécules d'isobutène retenues dans les pores de la ferrierite. Cette réaction autocatalytique rend très sélective en isobutène la transformation bimoléculaire du n-butène.

Published
2006
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2. Isomérisation des paraffines de C4 à C7 sur catalyseurs zéolithiques. Revue bibliographique Isomerization of C4 to C7 Paraffins on Zeolitic Catalysts (Bibliographic Review)

Author

Belloum M., Travers C., and Bournonville J. P.

Subjects
Chemical technology, TP1-1185, Energy industries. Energy policy. Fuel trade, HD9502-9502.5
Abstract

L'isomérisation des alcanes connaît un nouvel intérêt, depuis que la législation a prévu, par souci de protection de l'environnement, la suppression des alkyls de plomb dans les essences à l'horizon 1992. Cette réaction catalytique permet, en partant de n-paraffines de faible indice d'octane, issues du réformage catalytique ou de la distillation directe, d'obtenir des iso-paraffines présentant un indice d'octane beaucoup plus élevé. Elle est thermodynamiquement favorisée à basse température et nécessite par conséquent l'utilisation de catalyseurs développant une acidité importante. Deux types de catalyseurs sont actuellement utilisés industriellement : les catalyseurs à base de Pt sur lumine chlorée et les catalyseurs zéolithiques à base de Pt sur mordinite. Ces derniers sont considérés comme étant la nouvelle génération de catalyseurs. Ils présentent l'avantage d'être faciles à mettre en oeuvre et d'être beaucoup moins sensibles à la présence de poisons tels que soufre et eau dans la charge. Cependant ils conduisent à un gain d'octane considérablement plus faible que celui obtenu avec les catalyseurs Pt sur alumine chlorée. Cette étude bibliographique fait le point sur les différents mécanismes invoqués suivant le type de catalyseurs, les données cinétiques obtenues dans la littérature, et les différents procédés mis en oeuvre. Elle permet en particulier de mettre en évidence les contributions respectives des fonctions acides et métalliques pour l'isomérisation des alcanes de C4 à C7. En effet, il apparaît que suivant le type de catalyseurs utilisés, le mécanisme de la traction peut être bifonctionnel ou monofonctionnel acide. Dans certains cas, il pourrait même y avoir superposition des 2 mécanismes. L'étude de la longueur de la chaîne carbonée sur la réaction d'isomérisation ainsi que l'influence de la présence de composés cycliques, aromatiques ou non, ont également été envisagées. Il apparaît que la réactivité des alcanes augmente avec le nombre d'atomes de carbone et le degré de ramification de la molécule, et que la présence de composés aromatiques provoque une inhibition de la réaction d'isomérisation. Ce dernier point est très important pour l'industrie. There has been renewed interest in the isomerization of alkanes since legislation, with a view to environmental protection, has undertaken to eliminate lead alkyls from gasoline between now and 1992. Starting from low octane-number n-paraffins issuing from catalytic reforming or straight-run distillation, this catalytic reaction can be used to produce iso-paraffins having a much higher octane number. It is thermodynamically enhanced at low temperature and hence requires the use of catalysts developing high acidity. Two types of catalysts are currently used industrially, i. e. Pt base catalysts on chlorinated alumina and Pt base zeolitic catalysts on mordenite. These latter are considered to be the new generation of catalysts. They have the advantage of being easy to use and of being much less sensitive to the presence of poisons such as sulfur and water in the feedstock. However, they lead to a considerably lower improvement in octane than what is obtained with Pt catalysts on chlorinated alumina. This bibliographic study reviews the different mechanisms used according to the type of catalyst, the kinetic data obtained from the literature and the different processes used. In particular, it highlights the respective contributions of the acidic and metallic functions for the isomerization of C4 to C7 alkanes. Indeed, depending on the type of catalyst used, it appears the traction mechanism may be acidic bifunctional or monofunctional. In some cases two mechanisms might even be superposed. The study has also considered the effect of the length of this carbon chain on the isomerization reaction as well as the influence of the presence of ring compounds, whether aromatic or not. It seems that the reactivity of alkanes increases with the number of carbon atoms and with the degree of branching of the molecule, and that the presence of aromatic compounds inhibits the isomerization reaction. This last point is of great industrial importance.

Published
2006
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3. Safety and efficacy of tenecteplase in patients with wake-up stroke assessed by non-contrast CT (TWIST): a multicentre, open-label, randomised controlled trial

Author

Parson, M, Valente, M, Chen, A, Sharobeam, A, Edwards, L, Blair, C, Christensen, L, Ægidius, K, Pihl, T, Fassel-Larsen, C, Wassvik, L, Folke, M, Rosenbaum, S, Gharehbagh, S S, Hansen, A, Preisler, N, Antsov, K, Mallene, S, Lill, M, Herodes, M, Vibo, R, Rakitin, A, Saarinen, J, Tiainen, M, Tumpula, O, Noppari, T, Raty, S, Sibolt, G, Nieminen, J, Niederhauser, J, Haritoncenko, I, Puustinen, J, Haula, T-M, Sipilä, J, Viesulaite, B, Taroza, S, Rastenyte, D, Matijosaitis, V, Vilionskis, A, Masiliunas, R, Ekkert, A, Chmeliauskas, P, Lukosaitis, V, Reichenbach, A, Moss, T T, Nilsen, H Y, Hammer-Berntzen, R, Nordby, L M, Weiby, T A, Nordengen, K, Ihle-Hansen, H, Stankiewiecz, M, Grotle, O, Nes, M, Thiemann, K, Særvold, I M, Fraas, M, Størdahl, S, Horn, J W, Hildrum, H, Myrstad, C, Tobro, H, Tunvold, J-A, Jacobsen, O, Aamodt, N, Baisa, H, Malmberg, V N, Rohweder, G, Ellekjær, H, Ildstad, F, Egstad, E, Helleberg, B H, Berg, H H, Jørgensen, J, Tronvik, E, Shirzadi, M, Solhoff, R, Van Lessen, R, Vatne, A, Forselv, K, Frøyshov, H, Fjeldstad, M S, Tangen, L, Matapour, S, Kindberg, K, Johannessen, C, Rist, M, Mathisen, I, Nyrnes, T, Haavik, A, Toverud, G, Aakvik, K, Larsson, M, Ytrehus, K, Ingebrigtsen, S, Stokmo, T, Helander, C, Larsen, I C, Solberg, T O, Seljeseth, Y M, Maini, S, Bersås, I, Mathé, J, Rooth, E, Laska, A-C, Rudberg, A-S, Esbjörnsson, M, Andler, F, Ericsson, A, Wickberg, O, Karlsson, J-E, Redfors, P, Jood, K, Buchwald, F, Mansson, K, Gråhamn, O, Sjölin, K, Lindvall, E, Cidh, Å, Tolf, A, Fasth, O, Hedström, B, Fladt, J, Dittrich, T D, Kriemler, L, Hannon, N, Amis, E, Finlay, S, Mitchell-Douglas, J, McGee, J, Davies, R, Johnson, V, Nair, A, Robinson, M, Greig, J, Halse, O, Wilding, P, Mashate, S, Chatterjee, K, Martin, M, Leason, S, Roberts, J, Dutta, D, Ward, D, Rayessa, R, Clarkson, E, Teo, J, Ho, C, Conway, S, Aissa, M, Papavasileiou, V, Fry, S, Waugh, D, Britton, J, Hassan, A, Manning, L, Khan, S, Asaipillai, A, Fornolles, C, Tate, M L, Chenna, S, Anjum, T, Karunatilake, D, Foot, J, VanPelt, L, Shetty, A, Wilkes, G, Buck, A, Jackson, B, Fleming, L, Carpenter, M, Jackson, L, Needle, A, Zahoor, T, Duraisami, T, Northcott, K, Kubie, J, Bowring, A, Keenan, S, Mackle, D, England, T, Rushton, B, Hedstrom, A, Amlani, S, Evans, R, Muddegowda, G, Remegoso, A, Ferdinand, P, Varquez, R, Davis, M, Elkin, E, Seal, R, Fawcett, M, Gradwell, C, Travers, C, Atkinson, B, Woodward, S, Giraldo, L, Byers, J, Cheripelli, B, Lee, S, Marigold, R, Smith, S, Zhang, L, Ghatala, R, Sim, C H, Ghani, U, Yates, K, Obarey, S, Willmot, M, Ahlquist, K, Bates, M, Rashed, K, Board, S, Andsberg, G, Sundayi, S, Garside, M, Macleod, M-J, Manoj, A, Hopper, O, Cederin, B, Toomsoo, T, Gross-Paju, K, Tapiola, T, Kestutis, J, Amthor, K-F, Heermann, B, Ottesen, V, Melum, T A, Kurz, M, Parsons, M, Roaldsen, Melinda B, Eltoft, Agnethe, Wilsgaard, Tom, Christensen, Hanne, Engelter, Stefan T, Indredavik, Bent, Jatužis, Dalius, Karelis, Guntis, Kõrv, Janika, Lundström, Erik, Petersson, Jesper, Putaala, Jukka, Søyland, Mary-Helen, Tveiten, Arnstein, Bivard, Andrew, Johnsen, Stein Harald, Mazya, Michael V, Werring, David J, Wu, Teddy Y, De Marchis, Gian Marco, Robinson, Thompson G, and Mathiesen, Ellisiv B

Published
2023
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10. Association of mycoplasma and ureaplasma respiratory colonization and bronchopulmonary dysplasia in extremely preterm infants- a propensity score matched case-control study

Author

Vu, B, primary, Seales, C, additional, Rahman, A, additional, Travers, C, additional, Willis, KA, additional, Lal, CV, additional, Crabb, D, additional, Ratliff, A, additional, Atkinson, P, additional, Waites, K, additional, Carlo, WA, additional, Ambalavanan, N, additional, and Shukla, V, additional

Published
2023
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14. Safety and efficacy of tenecteplase in patients with wake-up stroke assessed by non-contrast CT (TWIST): a multicentre, open-label, randomised controlled trial

Author

Roaldsen, Melinda B, primary, Eltoft, Agnethe, additional, Wilsgaard, Tom, additional, Christensen, Hanne, additional, Engelter, Stefan T, additional, Indredavik, Bent, additional, Jatužis, Dalius, additional, Karelis, Guntis, additional, Kõrv, Janika, additional, Lundström, Erik, additional, Petersson, Jesper, additional, Putaala, Jukka, additional, Søyland, Mary-Helen, additional, Tveiten, Arnstein, additional, Bivard, Andrew, additional, Johnsen, Stein Harald, additional, Mazya, Michael V, additional, Werring, David J, additional, Wu, Teddy Y, additional, De Marchis, Gian Marco, additional, Robinson, Thompson G, additional, Mathiesen, Ellisiv B, additional, Parson, M, additional, Valente, M, additional, Chen, A, additional, Sharobeam, A, additional, Edwards, L, additional, Blair, C, additional, Christensen, L, additional, Ægidius, K, additional, Pihl, T, additional, Fassel-Larsen, C, additional, Wassvik, L, additional, Folke, M, additional, Rosenbaum, S, additional, Gharehbagh, S S, additional, Hansen, A, additional, Preisler, N, additional, Antsov, K, additional, Mallene, S, additional, Lill, M, additional, Herodes, M, additional, Vibo, R, additional, Rakitin, A, additional, Saarinen, J, additional, Tiainen, M, additional, Tumpula, O, additional, Noppari, T, additional, Raty, S, additional, Sibolt, G, additional, Nieminen, J, additional, Niederhauser, J, additional, Haritoncenko, I, additional, Puustinen, J, additional, Haula, T-M, additional, Sipilä, J, additional, Viesulaite, B, additional, Taroza, S, additional, Rastenyte, D, additional, Matijosaitis, V, additional, Vilionskis, A, additional, Masiliunas, R, additional, Ekkert, A, additional, Chmeliauskas, P, additional, Lukosaitis, V, additional, Reichenbach, A, additional, Moss, T T, additional, Nilsen, H Y, additional, Hammer-Berntzen, R, additional, Nordby, L M, additional, Weiby, T A, additional, Nordengen, K, additional, Ihle-Hansen, H, additional, Stankiewiecz, M, additional, Grotle, O, additional, Nes, M, additional, Thiemann, K, additional, Særvold, I M, additional, Fraas, M, additional, Størdahl, S, additional, Horn, J W, additional, Hildrum, H, additional, Myrstad, C, additional, Tobro, H, additional, Tunvold, J-A, additional, Jacobsen, O, additional, Aamodt, N, additional, Baisa, H, additional, Malmberg, V N, additional, Rohweder, G, additional, Ellekjær, H, additional, Ildstad, F, additional, Egstad, E, additional, Helleberg, B H, additional, Berg, H H, additional, Jørgensen, J, additional, Tronvik, E, additional, Shirzadi, M, additional, Solhoff, R, additional, Van Lessen, R, additional, Vatne, A, additional, Forselv, K, additional, Frøyshov, H, additional, Fjeldstad, M S, additional, Tangen, L, additional, Matapour, S, additional, Kindberg, K, additional, Johannessen, C, additional, Rist, M, additional, Mathisen, I, additional, Nyrnes, T, additional, Haavik, A, additional, Toverud, G, additional, Aakvik, K, additional, Larsson, M, additional, Ytrehus, K, additional, Ingebrigtsen, S, additional, Stokmo, T, additional, Helander, C, additional, Larsen, I C, additional, Solberg, T O, additional, Seljeseth, Y M, additional, Maini, S, additional, Bersås, I, additional, Mathé, J, additional, Rooth, E, additional, Laska, A-C, additional, Rudberg, A-S, additional, Esbjörnsson, M, additional, Andler, F, additional, Ericsson, A, additional, Wickberg, O, additional, Karlsson, J-E, additional, Redfors, P, additional, Jood, K, additional, Buchwald, F, additional, Mansson, K, additional, Gråhamn, O, additional, Sjölin, K, additional, Lindvall, E, additional, Cidh, Å, additional, Tolf, A, additional, Fasth, O, additional, Hedström, B, additional, Fladt, J, additional, Dittrich, T D, additional, Kriemler, L, additional, Hannon, N, additional, Amis, E, additional, Finlay, S, additional, Mitchell-Douglas, J, additional, McGee, J, additional, Davies, R, additional, Johnson, V, additional, Nair, A, additional, Robinson, M, additional, Greig, J, additional, Halse, O, additional, Wilding, P, additional, Mashate, S, additional, Chatterjee, K, additional, Martin, M, additional, Leason, S, additional, Roberts, J, additional, Dutta, D, additional, Ward, D, additional, Rayessa, R, additional, Clarkson, E, additional, Teo, J, additional, Ho, C, additional, Conway, S, additional, Aissa, M, additional, Papavasileiou, V, additional, Fry, S, additional, Waugh, D, additional, Britton, J, additional, Hassan, A, additional, Manning, L, additional, Khan, S, additional, Asaipillai, A, additional, Fornolles, C, additional, Tate, M L, additional, Chenna, S, additional, Anjum, T, additional, Karunatilake, D, additional, Foot, J, additional, VanPelt, L, additional, Shetty, A, additional, Wilkes, G, additional, Buck, A, additional, Jackson, B, additional, Fleming, L, additional, Carpenter, M, additional, Jackson, L, additional, Needle, A, additional, Zahoor, T, additional, Duraisami, T, additional, Northcott, K, additional, Kubie, J, additional, Bowring, A, additional, Keenan, S, additional, Mackle, D, additional, England, T, additional, Rushton, B, additional, Hedstrom, A, additional, Amlani, S, additional, Evans, R, additional, Muddegowda, G, additional, Remegoso, A, additional, Ferdinand, P, additional, Varquez, R, additional, Davis, M, additional, Elkin, E, additional, Seal, R, additional, Fawcett, M, additional, Gradwell, C, additional, Travers, C, additional, Atkinson, B, additional, Woodward, S, additional, Giraldo, L, additional, Byers, J, additional, Cheripelli, B, additional, Lee, S, additional, Marigold, R, additional, Smith, S, additional, Zhang, L, additional, Ghatala, R, additional, Sim, C H, additional, Ghani, U, additional, Yates, K, additional, Obarey, S, additional, Willmot, M, additional, Ahlquist, K, additional, Bates, M, additional, Rashed, K, additional, Board, S, additional, Andsberg, G, additional, Sundayi, S, additional, Garside, M, additional, Macleod, M-J, additional, Manoj, A, additional, Hopper, O, additional, Cederin, B, additional, Toomsoo, T, additional, Gross-Paju, K, additional, Tapiola, T, additional, Kestutis, J, additional, Amthor, K-F, additional, Heermann, B, additional, Ottesen, V, additional, Melum, T A, additional, Kurz, M, additional, and Parsons, M, additional

Published
2023
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35. The subjective world of home care workers in dementia: an 'order of worth' analysis

Author

Schneider, J, Pollock, K, Wilkinson, S, Perry-Young, L, Travers, C, and Turner, N

Subjects
ComputingMilieux_THECOMPUTINGPROFESSION
Abstract

The perspective of domiciliary workers is needed to recruit a high-quality workforce and meet growing demand. An English ethnographic study yielded extensive insights. To structure analysis of the study data, we apply a method developed by political theorists Boltanski and Thévenot that identifies key variables in different values systems. This “orders of worth” framework is used to map out the distinctive features of the subjective world of home carers. The results can be drawn on to formulate recruitment and retention policies, to design reward strategies or to ensure that training and education opportunities engage effectively with the workforce.

Published
2019

36. Using a Reflective Diary Method to Investigate the Experiences of Paid Home Care Workers Caring for People With Dementia

Author

Travers, C, Schneider, J, Perry-Young, L, Wilkinson, S, Scales, K, Pollock, K, Travers, C, Schneider, J, Perry-Young, L, Wilkinson, S, Scales, K, and Pollock, K

Abstract

This article reports on the use of an innovative reflective diary method with paid home care workers caring for people with dementia. It examines the key features of the diary design, recruitment and training of participants, diarists’ approaches and responses to diary-keeping, and evaluates the use of diaries in this context. Following training, 11 volunteers (all female) employed by a U.K.-based home care organization kept diaries of their experiences of caring for those with dementia. Using specially designed diaries, they wrote about their visits to clients for a period of approximately 4 months and were remunerated for up to 16 extra hours at their usual hourly rate of pay. Overall, home care workers engaged well with the process, keeping regular, lengthy, timely, and reflective diary entries. Diary-keeping provided a means for these workers to express their emotions about their work, while enhancing their self-insight and care practices. We demonstrate the feasibility of diaries for research with this occupational group and conclude that the written reflexivity employed in diaries can document, enrich, and improve the work of these caregivers.

Published
2019

42. The severity of pandemic H1N1 influenza in the United States, from April to July 2009: a Bayesian analysis

Author

Medina, W, Michelangelo, D, Milhofer, J, Milyavskaya, I, Misener, M, Mizrahi, J, Moskin, L, Motherwell, M, Myers, C, Nair, HP, Nguyen, T, Nilsen, D, Nival, J, Norton, J, Oleszko, W, Olson, C, Paladini, M, Palumbo, L, Papadopoulos, P, Parton, H, Paternostro, J, Paynter, L, Perkins, K, Perlman, S, Persaud, H, Peters, C, Pfeiffer, M, Platt, R, Pool, L, Punsalang, A, Rasul, Z, Rawlins, V, Reddy, V, Rinchiuso, A, Rodriguez, T, Rosal, R, Ryan, M, Sanderson, M, Scaccia, A, Seligson, AL, Seupersad, J, SevereDildy, J, Siddiqi, A, Siemetzki, U, Glaser, M, Girdharrie, L, Singh, T, Slavinski, S, Slopen, M, Snuggs, T, Starr, D, Stayton, C, Fung, L, Fu, J, Friedman, S, Frieden, T, France, AM, Stoute, A, Terlonge, J, Ternier, A, Thorpe, L, Travers, C, Tsoi, B, Turner, K, Tzou, J, Vines, S, Waddell, EN, Walker, D, Warner, C, Weisfuse, I, Weiss, D, WilliamsAkita, A, Wilson, E, Fitzgerald, K, Harper, S, Hasnain, Q, Hedge, S, Heller, M, Hendrickson, D, Herskovitz, A, Hinterland, K, Holmes, R, Hom, J, Hon, J, Hopke, T, Hsieh, J, Hughes, S, Immerwahr, S, Incalicchio, AM, Jasek, J, Jimenez, J, Johns, M, Jones, L, Jordan, H, Kambili, C, Kang, J, Kapell, D, Karpati, A, Kerker, B, Konty, K, Kornblum, J, Krigsman, G, Laraque, F, Layton, M, Lee, E, Lee, L, Lee, S, Lim, S, Marx, M, McGibbon, E, Mahoney, K, Marin, G, Matte, T, McAnanama, R, McKay, R, McKay, C, McVeigh, K, Medina, E, Fireteanu, AM, Fine, A, FilsAime, C, Fernandez, M, Feliciano, R, Farley, S, Evans, M, Eisenhower, D, Egger, J, Edwin, B, Edghill, Z, Wong, M, Wu, C, Yang, D, Younis, M, Yusuff, S, Zimmerman, C, Zucker, J, Eavey, J, Durrah, J, Duquaine, D, DiGrande, L, DiCaprio, K, Diaz, L, Deocharan, B, Del Cid, O, DeGrechie, S, DeGrasse, A, Darkins, B, Daniels, A, Da Costa, CA, Crouch, B, Coyle, C, Costarella, R, Corey, C, Cook, D, Cook, H, Cone, J, Cimini, D, Chamany, S, Camurati, L, Campbell, M, Cajigal, A, Cai, L, Butts, B, Burke, M, Bregman, B, Bornschlegel, K, Blank, S, Betz, J, Berger, M, Berg, D, Bell, G, Begier, E, Beaudry, G, Beatrice, ST, Barbot, O, Balter, S, Backman, P, Atamian, J, Aston, C, AgborTabi, E, Adman, G, Adamski, A, Ackelsberg, J, Lipsitch, M, Biedrzycki, P, Finelli, L, Cooper, BS, Riley, S, Reed, C, Hagy, A, De Angelis, D, Presanis, AM, Goranson, C, Griffing, F, Gupta, L, Hamilton, C, Hanson, H, HartmanO'Connell, I, and Team, The New York City Swine Flu Investigation

Subjects
medicine.medical_specialty, Pediatrics, Hospitalization - statistics and numerical data, medicine.medical_treatment, Population, Public Health and Epidemiology/Infectious Diseases, Influenza, Human - classification - epidemiology, Disease Outbreaks, 03 medical and health sciences, 0302 clinical medicine, Influenza A Virus, H1N1 Subtype, Epidemiology, Pandemic, Severity of illness, Infectious Diseases/Viral Infections, medicine, Credible interval, 030212 general & internal medicine, Young adult, education, Mechanical ventilation, 0303 health sciences, education.field_of_study, 030306 microbiology, business.industry, Incidence (epidemiology), virus diseases, Bayes Theorem, General Medicine, 3. Good health, Medicine, business, Research Article
Abstract

Marc Lipsitch and colleagues use complementary data from two US cities, Milwaukee and New York City, to assess the severity of pandemic (H1N1) 2009 influenza in the United States., Background Accurate measures of the severity of pandemic (H1N1) 2009 influenza (pH1N1) are needed to assess the likely impact of an anticipated resurgence in the autumn in the Northern Hemisphere. Severity has been difficult to measure because jurisdictions with large numbers of deaths and other severe outcomes have had too many cases to assess the total number with confidence. Also, detection of severe cases may be more likely, resulting in overestimation of the severity of an average case. We sought to estimate the probabilities that symptomatic infection would lead to hospitalization, ICU admission, and death by combining data from multiple sources. Methods and Findings We used complementary data from two US cities: Milwaukee attempted to identify cases of medically attended infection whether or not they required hospitalization, while New York City focused on the identification of hospitalizations, intensive care admission or mechanical ventilation (hereafter, ICU), and deaths. New York data were used to estimate numerators for ICU and death, and two sources of data—medically attended cases in Milwaukee or self-reported influenza-like illness (ILI) in New York—were used to estimate ratios of symptomatic cases to hospitalizations. Combining these data with estimates of the fraction detected for each level of severity, we estimated the proportion of symptomatic patients who died (symptomatic case-fatality ratio, sCFR), required ICU (sCIR), and required hospitalization (sCHR), overall and by age category. Evidence, prior information, and associated uncertainty were analyzed in a Bayesian evidence synthesis framework. Using medically attended cases and estimates of the proportion of symptomatic cases medically attended, we estimated an sCFR of 0.048% (95% credible interval [CI] 0.026%–0.096%), sCIR of 0.239% (0.134%–0.458%), and sCHR of 1.44% (0.83%–2.64%). Using self-reported ILI, we obtained estimates approximately 7–9× lower. sCFR and sCIR appear to be highest in persons aged 18 y and older, and lowest in children aged 5–17 y. sCHR appears to be lowest in persons aged 5–17; our data were too sparse to allow us to determine the group in which it was the highest. Conclusions These estimates suggest that an autumn–winter pandemic wave of pH1N1 with comparable severity per case could lead to a number of deaths in the range from considerably below that associated with seasonal influenza to slightly higher, but with the greatest impact in children aged 0–4 and adults 18–64. These estimates of impact depend on assumptions about total incidence of infection and would be larger if incidence of symptomatic infection were higher or shifted toward adults, if viral virulence increased, or if suboptimal treatment resulted from stress on the health care system; numbers would decrease if the total proportion of the population symptomatically infected were lower than assumed. Please see later in the article for the Editors' Summary, Editors' Summary Background Every winter, millions of people catch influenza—a viral infection of the airways—and about half a million people die as a result. In the US alone, an average of 36,000 people are thought to die from influenza-related causes every year. These seasonal epidemics occur because small but frequent changes in the virus mean that an immune response produced one year provides only partial protection against influenza the next year. Occasionally, influenza viruses emerge that are very different and to which human populations have virtually no immunity. These viruses can start global epidemics (pandemics) that kill millions of people. Experts have been warning for some time that an influenza pandemic is long overdue and in, March 2009, the first cases of influenza caused by a new virus called pandemic (H1N1) 2009 (pH1N1; swine flu) occurred in Mexico. The virus spread rapidly and on 11 June 2009, the World Health Organization declared that a global pandemic of pH1N1 influenza was underway. By the beginning of November 2009, more than 6,000 people had died from pH1N1 influenza. Why Was This Study Done? With the onset of autumn—drier weather and the return of children to school help the influenza virus to spread—pH1N1 cases, hospitalizations, and deaths in the Northern Hemisphere have greatly increased. Although public-health officials have been preparing for this resurgence of infection, they cannot be sure of its impact on human health without knowing more about the severity of pH1N1 infections. The severity of an infection can be expressed as a case-fatality ratio (CFR; the proportion of cases that result in death), as a case-hospitalization ratio (CHR; the proportion of cases that result in hospitalization), and as a case-intensive care ratio (CIR; the proportion of cases that require treatment in an intensive care unit). Because so many people have been infected with pH1N1 since it emerged, the numbers of cases and deaths caused by pH1N1 infection are not known accurately so these ratios cannot be easily calculated. In this study, the researchers estimate the severity of pH1N1 influenza in the US between April and July 2009 by combining data on pH1N1 infections from several sources using a statistical approach known as Bayesian evidence synthesis. What Did the Researchers Do and Find? By using data on medically attended and hospitalized cases of pH1N1 infection in Milwaukee and information from New York City on hospitalizations, intensive care use, and deaths, the researchers estimate that the proportion of US cases with symptoms that died (the sCFR) during summer 2009 was 0.048%. That is, about 1 in 2,000 people who had symptoms of pH1N1 infection died. The “credible interval” for this sCFR, the range of values between which the “true” sCFR is likely to lie, they report, is 0.026%–0.096% (between 1 in 4,000 and 1 in 1,000 deaths for every symptomatic case). About 1 in 400 symptomatic cases required treatment in intensive care, they estimate, and about 1 in 70 symptomatic cases required hospital admission. When the researchers used a different approach to estimate the total number of symptomatic cases—based on New Yorkers' self-reported incidence of influenza-like-illness from a telephone survey—their estimates of pH1N1 infection severity were 7- to 9-fold lower. Finally, they report that the sCFR and the sCIR were highest in people aged 18 or older and lowest in children aged 5–17 years. What Do These Findings Mean? Many uncertainties (for example, imperfect detection and reporting) can affect estimates of influenza severity. Even so, the findings of this study suggest that an autumn–winter pandemic wave of pH1N1 will have a death toll only slightly higher than or considerably lower than that caused by seasonal influenza in an average year, provided pH1N1 continues to behave as it did during the summer. Similarly, the estimated burden on hospitals and intensive care facilities ranges from somewhat higher than in a normal influenza season to considerably lower. The findings of this study also suggest that, unlike seasonal influenza, which kills mainly elderly adults, a high proportion of deaths from pH1N1infection will occur in nonelderly adults, a shift in age distribution that has been seen in previous pandemics. With these estimates in hand and with continued close monitoring of the pandemic, public-health officials should now be in a better position to plan effective strategies to deal with the pH1N1 pandemic. Additional Information Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000207. The US Centers for Disease Control and Prevention provides information about influenza for patients and professionals, including specific information on pandemic H1N1 (2009) influenza Flu.gov, a US government Web site, provides access to information on H1N1, avian and pandemic influenza The World Health Organization provides information on seasonal influenza and has detailed information on pandemic H1N1 (2009) influenza (in several languages) The UK Health Protection Agency provides information on pandemic influenza and on pandemic H1N1 (2009) influenza More information for patients about H1N1 influenza is available through Choices, an information resource provided by the UK National Health Service

Published
2016

46. Investigation of semiconducting YBaCuO thin films: A new room temperature bolometer.

Author

Shan, P. C., Çelik-Butler, Z., Butler, D. P., Jahanzeb, A., Travers, C. M., Kula, W., and Sobolewski, Roman

Subjects
THIN films, SEMICONDUCTORS, MICROMACHINING
Abstract

Presents a study which investigated the application of the semiconducting phases of YBaCuO thin films as a bolometer for uncooled infrared detection. Structures of the buffer layers; Integration of the thin film in silicon micromachining technology; Resistance of thin films.

Published
1996
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50. Prévalence de la BPCO en milieu agricole dans deux régions françaises

Author

Guillien, A., primary, Puyraveau, M., additional, Guillot, S., additional, Rannou, F., additional, Marquette, D., additional, Berger, P., additional, Travers, C., additional, Lornet, J.M., additional, Monnet, E., additional, Mauny, F., additional, Laplante, J.J., additional, Dalphin, J.C., additional, and Degano, B., additional

Published
2015
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