992 resultados para FT-Rheologie, Polymere, Dielektrik
Resumo:
J. A. Gallagher, A. J. Cairns and C. J. Pollock (2004). Cloning and characterization of a putative fructosyltransferase and two putative invertase genes from the temperate grass Lolium temulentum L. Journal of Experimental Botany, 55 (397) pp.557-569 Sponsorship: BBSRC RAE2008
Resumo:
Wydział Chemii: Zakład Biochemii
Resumo:
Wydział Chemii
Resumo:
Signaturas: *6, A-F4, G2, H-Z4, 2A-2Z4, 3A-3Z4, 4A-4Z4, 5A-5D4, 5E2, 5F4 ; *5, A-Z4, 2A-2Z4, 3A-3Y4, Z2, 4A4 ; *5, A-Z4, 2A-2Z4, 3A-3Z4, 4A-4N4, 4O5 ; *5, A-Z4, 2A-2Z4, 3A-3Z4, 4A-4O4, 4P2, 4Q1, 4R4 ; *5, A-Z4, 2A-2Z4, 3A-3M4, *2, A-S4.
Resumo:
Focal therapy (FT) for the management of clinically localized prostate cancer (PCa) is growing from a concept to reality because of increased interest of both patients and physicians. Selection protocols, however, are yet to be established. We discuss the role of prostate biopsy in candidate selection for FT and highlight the different strategies and technical aspects of the use of prostate biopsy in this setting. In our opinion, prostate biopsy plays a major role in the selection process and tailoring appropriate treatment strategy to the patient. FT necessitates dedicated biopsy schemes that would reliably predict the extent, nature, and location of PCa in selected patients. Currently, there is insufficient scientific evidence to propose a specific biopsy scheme that could fit every candidate, providing accurate characterization of the disease in the individual patient. Further research is necessary to establish solid selection protocols that would reliably identify appropriate candidates for FT of PCa.
Resumo:
Articular cartilage possesses complex mechanical properties that provide healthy joints the ability to bear repeated loads and maintain smooth articulating surfaces over an entire lifetime. In this study, we utilized a fiber-reinforced composite scaffold designed to mimic the anisotropic, nonlinear, and viscoelastic biomechanical characteristics of native cartilage as the basis for developing functional tissue-engineered constructs. Three-dimensionally woven poly(epsilon-caprolactone) (PCL) scaffolds were encapsulated with a fibrin hydrogel, seeded with human adipose-derived stem cells, and cultured for 28 days in chondrogenic culture conditions. Biomechanical testing showed that PCL-based constructs exhibited baseline compressive and shear properties similar to those of native cartilage and maintained these properties throughout the culture period, while supporting the synthesis of a collagen-rich extracellular matrix. Further, constructs displayed an equilibrium coefficient of friction similar to that of native articular cartilage (mu(eq) approximately 0.1-0.3) over the prescribed culture period. Our findings show that three-dimensionally woven PCL-fibrin composite scaffolds can be produced with cartilage-like mechanical properties, and that these engineered properties can be maintained in culture while seeded stem cells regenerate a new, functional tissue construct.
Resumo:
Intensive archaeological investigation was undertaken on an urban backlot in Annapolis, Maryland. Fieldwork was conducted on behalf of Historic Annapolis Foundation for the property's owners, King and Cornwall, Inc. Supplemental documentary research, an evaluation of existing conditions on the property, and below-ground excavation of a 35 X 70 ft. urban backlot were conducted. While the project was not a Section 106 compliance effort, the field methods and rationale for the site's investigation are comparable to those of standard Phase II site evaluations. Historical documentation attested to the fact that the 22 West Street Backlot, located along the western most edge of the Historic District of Annapolis, Maryland, had seen development and occupation since the first quarter of the eighteenth century. A substantial brick structure was known to have occupied the property in a series of altered forms for much of that period. This structure served a variety of purposes over time: a private residence in the eighteenth century, a boarding house in the nineteenth century (known as the National Hotel), a duplex in the early twentieth century, half of which remained in use until the structure was entirely razed in the 1970s after destruction by fire. Recovery and analysis of site formation processes (i.e., both cultural and natural transformations of the buried remains) indicated that sections of the site were disturbed to a depth of six feet. In contrast to what initially seemed a poor prognosis for site integrity, other areas of the backlot revealed numerous intact historical features and deposits. Structural remains from the dwelling and its associated outbuildings, additions, and attendant trash deposits were recovered. What was initiated as a program of limited testing evolved into a larger-scale undertaking that made use of largely hand-excavated units in conjunction with machine-assisted stripping of areas demonstrated to contain from four to six-foot deep sterile layers of fill. The current investigations provided a window into a portion of the city and period in its history not documented archaeologically. Moreover, this project provided valuable insight into the archaeology of the homelot within a lightly industrialized, urban context. Evidence was recovered of shifts in the layout and arrangement of the houselot as well as changing relations between individuals and the workplace--all within an urban context--an issue defined elsewhere in the archaeological literature as a significant one. No further investigations are recommended for the site, however, further analysis and interpretation of materials recovered are ongoing. In the event that the site were to undergo development, monitoring of any construction activity is recommended.
Resumo:
In the fall of 1989, emergency excavation was undertaken in conjunction with restoration work at the John Brice II (Jennings-Brice) House, 18AP53. The exact date of construction for this brick home is problematic, and it was hoped that archaeological investigation could provide conclusive evidence to firmly establish the structure's date of construction. Excavation of one 5 X 5 ft. unit revealed the presence of 10 separate soil layers and four features of note, described in detail below. Unfortunately, no builders trench or similar feature by which we might date the house's construction was recovered. Future plans and possibilities for excavation at the property are outlined with the hopes of performing subsequent work at this rich site. We anticipate a focus on the arrangement and changes in use of the houselot, amassing evidence to support the presence of a vernacular garden on the property during the 18th century, as well as researching refuse disposal patterns, and clues to changing lifeways through the 18th century.
Resumo:
La floración es el resultado de complejas interacciones entre factores ambientales, y está mediada por señales endógenas y por el programa genético de la planta. Las respuestas a la floración fueron poco estudiadas en especies perennes facultativas como la autóctona Lesquerella mendocina, potencial cultivo oleaginoso. El objetivo general fue generar avances en el conocimiento de los mecanismos que regulan la floración en especies herbáceas perennes, utilizando a L. mendocina como objeto de estudio. Se caracterizó el papel de factores que controlan el crecimiento en la regulación del tiempo a floración, encontrándose una asociación entre la adquisición de una tasa de crecimiento Umbral (TCu) y el momento de floración, que resultó ser de naturaleza causal. Se puso en evidencia la participación de las giberelinas en la cascada de eventos que, iniciada por la adquisición de la TCU, desemboca en la iniciación floral. La exposición de las plantas a condiciones que aumentan la tasa de crecimiento (i.e. alta radiación incidente) suprimió la expresión del gen que codifica para la enzima GA2-oxidasa (lo que conduciría a la acumulación de giberelinas activas) y aumentó la proteína codificada por el gen FT. Además, se corroboró un rol positivo de los carbohidratos que actuarían como una señal a distancia para desencadenar la floración. Sobre la base de estos resultados, se elaboró un modelo conceptual para explicar los mecanismos que regulan la transición del estado vegetativo a reproductivo en L. mendocina, que se integra con conocimientos previos acerca del efecto de la temperatura sobre el desencadenamiento de la floración en esta especie. La información obtenida en esta tesis implica un avance en el conocimiento de los mecanismos que controlan la inducción a floración en especies perennes, y además sienta las bases para la puesta en cultivo y diseño de estrategias de manejo de cultivos alternativos con estas características.
Resumo:
Guest-host interactions of ibuprofen tromethamine salt (Ibu.T) with native and modified cyclodextrins (CyDs) have been investigated using several techniques, namely phase solubility diagrams (PSDs), proton nuclear magnetic resonance (H-1 NMR), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffractometry (XRPD). scanning-electron microscopy (SEM) and molecular mechanics (MM). From the analysis of PSD data (A(L)-type) it is concluded that the anionic tromethamine salt of ibuprofen (pK(a) = 4.55) forms 1: 1 soluble complexes with all CyDs investigated in buffered water at pH 7.0, while the neutral form of Ibu forms an insoluble complex with beta-CyD (B-S-type) in buffered water at pH 2.0. Ibu.T has a lower tendency to complex with beta-CyD (K-11 = 58 M-1 at pH 7.0) compared with the neutral Ibu (K-11 = 4200 M (1)) in water. Complex formation of Ibu.T with beta-CyD (Delta G degrees = -20.4 kJ/mol) is enthalpy driven (Delta H degrees = -22.9 kJ/mol) and is accompanied by a small unfavorable entropy (Delta S degrees = -8.4 J/mol K) change. H-1 NMR studies and MM computations revealed that, on complexation, the hydrophobic central benzene ring of lbu.T and part of the isobutyl group reside within the beta-CyD cavity leaving the peripheral groups (carboxylate, tromethamine and methyl groups) located near the hydroxyl group networks at either rim of beta-CyD. PSD, H-1 NMR, DSC, FT-IR, XRPD, SEM and MM studies confirmed the formation of Ibu.T/beta-CyD inclusion complex in solution and the solid state. (C) 2009 Elsevier B.V. All rights reserved.
Resumo:
B3-LYP/cc-pVDZ calculations of the gas-phase structure and vibrational spectra of the isolated molecule cyclo(L-Ser-L-Ser), a cyclic di-amino acid peptide (CDAP), were carried out by assuming C-2 symmetry. It is predicted that the minimum-energy structure is a boat conformation for the diketopiperazine (DKP) ring with both L-Beryl side chains being folded slightly above the ring. An additional structure of higher energy (15.16 kJ mol(-1)) has been calculated for a DKP ring with a planar geometry, although in this case two fundamental vibrations have been calculated with imaginary wavenumbers. The reported X-ray crystallographic structure of cyclo(L-Ser-L-Ser), shows that the DKP ring displays a near-planar conformation, with both the two L-Beryl side chains being folded above the ring. It is hypothesized that the crystal packing forces constrain the DKP ring in a planar conformation and it is probable that the lower energy boat conformation may prevail in the aqueous environment. Raman scattering and Fourier-transform infrared (FT-IR) spectra of solid state and aqueous solution samples of cyclo(L-Ser-L-Ser) are reported and discussed. Vibrational band assignments have been made on the basis of comparisons with the calculated vibrational spectra and band wavenumber shifts upon deuteration of labile protons. The experimental Raman and IR results for solid-state samples show characteristic amide I vibrations which are split (Raman:1661 and 1687 cm(-1), IR:1666 and 1680 cm(-1)), possibly due to interactions between molecules in a crystallographic unit cell. The cis amide I band is differentiated by its deuterium shift of ~ 30 cm(-1), which is larger than that previously reported for trans amide I deuterium shifts. A cis amide II mode has been assigned to a Raman band located at 1520 cm(-1). The occurrence of this cis amide II mode at a wavenumber above 1500 cm(-1) concurs with results of previously examined CDAP molecules with low molecular weight substituents on the C-alpha atoms, and is also indicative of a relatively unstrained DKP ring.
Resumo:
Experimental Raman and FT-IR spectra of solid-state non-deuterated and N-deuterated samples of cyclo(L-Met-L-Met) are reported and discussed. The Raman and FT-IR results show characteristic amide I vibrations (Raman: 1649 cm-1, infrared: 1675 cm-1) for molecules exhibiting a cis amide conformation. A Raman band, assigned to the cis amide II vibrational mode, is observed at sim1493 cm-1 but no IR band is observed in this region. Cyclo(L-Met-L-Met) crystallises in the triclinic space group P1 with one molecule per unit cell. The overall shape of the diketopiperazine (DKP) ring displays a (slightly distorted) boat conformation. The crystal packing employs two strong hydrogen bonds, which traverse the entire crystal via translational repeats. B3-LYP/cc-pVDZ calculations of the structure of the molecule predict a boat conformation for the DKP ring, in agreement with the experimentally determined X-ray structure. Copyright © 2009 John Wiley & Sons, Ltd.
Resumo:
Cyclo(L-Glu-L-Glu) has been crystallised in two different polymorphic forms. Both polymorphs are monoclinic, but form 1 is in space group P21 and form 2 is in space group C2. Raman scattering and FT-IR spectroscopic studies have been conducted for the N,O-protonated and deuterated derivatives. Raman spectra of orientated single crystals, solid-state and aqueous solution samples have also been recorded. The different hydrogen-bonding patterns for the two polymorphs have the greatest effect on vibrational modes with N&bond;H and C&dbond;O stretching character. DFT (B3-LYP/cc-pVDZ) calculations of the isolated cyclo(L-Glu-L-Glu) molecule predict that the minimum energy structure, assuming C2 symmetry, has a boat conformation for the diketopiperazine ring with the two L-Glu side chains being folded above the ring. The calculated geometry is in good agreement with the X-ray crystallographic structures for both polymorphs. Normal coordinate analysis has facilitated the band assignments for the experimental vibrational spectra. Copyright © 2009 John Wiley & Sons, Ltd.