811 resultados para polyethyleneglycol (PEG)
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We present the first far-IR observations of the solar-type stars δ Pav, HR 8501, 51 Peg and ζ^2 Ret, taken within the context of the DUNES Herschel open time key programme (OTKP). This project uses the PACS and SPIRE instruments with the objective of studying infrared excesses due to exo-Kuiper belts around nearby solar-type stars. The observed 100 μm fluxes from δ Pav, HR 8501, and 51 Peg agree with the predicted photospheric fluxes, excluding debris disks brighter than L_dust/L_* ~ 5 x 10^-7 (1σ level) around those stars. A flattened, disk-like structure with a semi-major axis of ~100 AU in size is detected around ζ2 Ret. The resolved structure suggests the presence of an eccentric dust ring, which we interpret as an exo-Kuiper belt with L_dust/L_* ≈ 10^-5.
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The more advantageous hepatitis C virus (HCV) inhibitors (most of them incorporating polysubstituted prolines or pyrrolidines) are detailed in this paper. The improvement of current treatments by combination of antiviral drugs is the driving force of this race to reduce the fast proliferation of this virus. The enhancement of efficiency in short periods of treatment is crucial in the economical point of view and for the hope of all infected people. New protease or polymerase inhibitors have been recently developed in order to substitute the traditional highly toxic PEG-interferon α-2b/ribavirin tandem. The contribution of our group in this field concerns the elaboration of the first and second generation GSK polymerase inhibitors through enantioselective processes based on silver(I)- and gold(I)-catalyzed 1,3-dipolar cycloadditions of azomethine ylides.
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The disintegration under composting conditions of films based on poly(lactic acid)–poly(hydroxybutyrate) (PLA–PHB) blends and intended for food packaging was studied. Two different plasticizers, poly(ethylene glycol) (PEG) and acetyl-tri-n-butyl citrate (ATBC), were used to limit the inherent brittleness of both biopolymers. Neat PLA, plasticized PLA and PLA–PHB films were processed by melt-blending and compression molding and they were further treated under composting conditions in a laboratory-scale test at 58 ± 2 °C. Disintegration levels were evaluated by monitoring their weight loss at different times: 0, 7, 14, 21 and 28 days. Morphological changes in all formulations were followed by optical and scanning electron microscopy (SEM). The influence of plasticizers on the disintegration of PLA and PLA–PHB blends was studied by evaluating their thermal and nanomechanical properties by thermogravimetric analysis (TGA) and the nanoindentation technique, respectively. Meanwhile, structural changes were followed by Fourier transformed infrared spectroscopy (FTIR). The ability of PHB to act as nucleating agent in PLA–PHB blends slowed down the PLA disintegration, while plasticizers speeded it up. The relationship between the mesolactide to lactide forms of PLA was calculated with a Pyrolysis–Gas Chromatography–Mass Spectrometry device (Py–GC/MS), revealing that the mesolactide form increased during composting.
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Poly(lactic acid) PLA, and poly(hydroxybutyrate) PHB, blends were processed as films and characterized for their use in food packaging. PLA was blended with PHB to enhance the crystallinity. Therefore, PHB addition strongly increased oxygen barrier while decreased the wettability. Two different environmentally-friendly plasticizers, poly(ethylene glycol) (PEG) and acetyl(tributyl citrate) (ATBC), were added to these blends to increase their processing performance, while improving their ductile properties. ATBC showed higher plasticizer efficiency than PEG directly related to the similarity solubility parameters between ATBC and both biopolymers. Moreover, ATBC was more efficiently retained to the polymer matrix during processing than PEG. PLA–PHB–ATBC blends were homogeneous and transparent blends that showed promising performance for the preparation of films by a ready industrial process technology for food packaging applications, showing slightly amber color, improved elongation at break, enhanced oxygen barrier and decreased wettability.
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Azomethine ylides, generated from imine-derived O-cinnamyl or O-crotonyl salicylaldeyde and α-amino acids, undergo intramolecular 1,3-dipolar cycloaddition, leading to chromene[4,3-b]pyrrolidines. Two reaction conditions are used: (a) microwave-assisted heating (200 W, 185 °C) of a neat mixture of reagents, and (b) conventional heating (170 °C) in PEG-400 as solvent. In both cases, a mixture of two epimers at the α-position of the nitrogen atom in the pyrrolidine nucleus was formed through the less energetic endo-approach (B/C ring fusion). In many cases, the formation of the stereoisomer bearing a trans-arrangement into the B/C ring fusion was observed in high proportions. Comprehensive computational and kinetic simulation studies are detailed. An analysis of the stability of transient 1,3-dipoles, followed by an assessment of the intramolecular pathways and kinetics are also reported.
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Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014
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Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014
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In response to the sustained pressure recently experienced by the Danish krone, Denmark may be forced to abandon its 30-year old peg to the euro. If this scenario unfolds, this CEPS Commentary argues that it will be no bad thing for the eurozone.
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Back Row: head coach Gloria Soluk, ass't coach Marthe McLean, Terrie Soullier, Cheryl Sobkow, ?, Patrice Donovan, Suzanne Dietz, Diana Wiley, ?, ?
Front Row: Cindy Baumgart, Connie Doutt, co-captain K.D. Harte, co-captain Diane Dietz, Peg Harte, Lori Gnatkowski
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Back Row: head coach Gloria Soluk, ass't coach Marthe McLean, Terrie Soullier, Cheryl Sobkow, ?, Patrice Donovan, Suzanne Dietz, Diana Wiley, ?, ?
Front Row: Cindy Baumgart, Connie Doutt, co-captain K.D. Harte, co-captain Diane Dietz, Peg Harte, Lori Gnatkowski
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Back Row: coach Gloria Soluk, manager Bridget Brennen, Orethia Lilly, Amy Rembisz, Connie Tudor, Sandy Svoboda, Wendy Bradetich, Carolyn Henry, manager Andrea Wilcox, trainer Sharon Schoelkopf
Front Row: Connie Doutt, Diana Wiley, Peg Harte, Terri Soullier, Cindy Baumgart, Lori Gnatkowski
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Front Left, clockwise: Laura Melvin, Lisa Vahi, head coach Joyce Davis, Heather Olson, Kim Clover, Carla Hunter, Jayne Hickman, Karen Marshall, Debi Bailey, Marie-Anne Davidson, student assistant Jenne Hickman, assistant coach Peg McCarthy, Julie Marshall, Toni Hall, Wendy Raber
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Back Row: asst. coach Peg McCarthy, Kim Clover, Carla Hunter, Marie-Ann Davidson, Julian Sturm, Karen Marshall, head coach Joyce Davis
Front Row: trainer Kara Mensel, Julie Marshall, co-captain Heather Olsen, co-captain Lisa Vahi, Laura Melvin, Wendy Raber
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Transportation Department, Office of University Research, Washington, D.C.
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National Highway Traffic Safety Administration, Washington, D.C.