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71.
Stone N Hart Prieto MC Crow P Uff J Ritchie AW 《Analytical and bioanalytical chemistry》2007,387(5):1657-1668
Near-infrared Raman spectroscopy, an optical technique that is able to interrogate biological tissues, has been used to study
bladder and prostate tissues, with the objective being to provide a first approximation of gross biochemical changes associated
with the process of carcinogenesis. Prostate samples for this study were obtained by taking a chip at TURP, and bladder samples
from a biopsy taken at TURBT and TURP, following ethical approval. Spectra were taken from purchased biochemical constituents
and different pathologies within the bladder and the prostate. We were then able to determine the biochemical basis for these
pathologies by utilising an ordinary least-squares fit. We have shown for the first time that we are able to utilise Raman
spectroscopy in determining the biochemical basis for the different pathologies within the bladder and prostate gland. In
this way we can achieve a better understanding of disease processes such as carcinogenesis. This could have major implications
in the future of the diagnosis of disease within the bladder and the prostate gland. 相似文献
72.
Barata JF Barros CM Santana-Marques MG Neves MG Faustino MA Tomé AC Ferrer Correia AJ Cavaleiro JA 《Journal of mass spectrometry : JMS》2007,42(2):225-232
Liquid secondary ion and electrospray mass spectrometry were used to study the complexation in-source of 5,10,15-tris(pentafluorophenyl)corrole with several divalent transition-metal ions. The metallocorrole ions formed in-source were identified by comparing their product ion mass spectra with the spectra of the same ions formed from metallocorroles obtained from classical procedures. Positive metallocorrole ion formation is accompanied by oxidation of the metal centre. Mechanisms were proposed for the oxidation processes, and data from negative-ion spectra reinforced these mechanisms. 相似文献
73.
The relative importance of local and long range interactions in the characteristics of the protein folding process has long been a matter of controversy. Computer simulations based on Gō-type models have been widely used to study this topic, but without much agreement on which type of interactions is more relevant for the foldability of a protein. In this work, the authors also employ a topology-based potential and simulation model to analyze the influence of local and long range interactions on the thermodynamics of the folding transition. The former are mainly used to control the degree of flexibility (or stiffness) of the chain, mostly appreciable in the unfolded (noncompact) state. Our results show the different effects that local and nonlocal interactions have on the entropy and the energy of the system. This implies that a balance between both types of interactions is required, so that a free energy barrier exists between the native and the denatured states. The variations in the contribution of both types of interactions have also a direct effect on the stability of the chain conformations, including the possible appearance of thermodynamic folding intermediates. 相似文献
74.
Neumann MG Schmitt CC Prieto KR Goi BE 《Journal of colloid and interface science》2007,315(2):810-813
A method based on the aggregate to monomol emission ratio, I(aggr)/I(monomol), was used to determine the minimal hydrotropic concentration (MHC) of aromatic hydrotropes. The main advantage of this method is that it does not require the use of probes or other additives, which might disrupt the aggregation process. Also, it relies on spectrophotometric measurements, which are more sensitive and less arduous than others, like conductivity, light scattering and surface tension. 相似文献
75.
Taboada L Prieto L Vidal P Espinosa JF Erickson JA 《Journal of combinatorial chemistry》2007,9(5):748-755
Here we describe a multistep solid-phase synthetic approach for the addition of amino acid residues to both the C- and N-termini of a phenylstatine core, yielding a library aimed at the development of structure-activity relationships in the S2 and S2' regions of the aspartyl proteases. Optimization of the synthetic strategy was performed on the basis of the in situ analysis of the compounds bound to the solid support through high-resolution magic angle spinning NMR Spectroscopy (HR-MAS NMR). 相似文献
76.
Arnaldo Alzrreca Eliud Hernndez Edgar Mangual Jos A. Prieto 《Journal of heterocyclic chemistry》1999,36(2):555-558
The low temperature addition of dilithiomethylphenyl sulfone to 2,3-O-isopropylidene-D-erythronolactone, and to 5-O-(tert-butyldimethylsilyl)-2,3-O-isopropylidene-D-ribofuranolactone gives the lactols 2 and 3a , respectively. Dehydration of lactol 2 in the presence of boron trifluoride etherate produces tetrahydrofuranylidene sulfones 5 and 6 in good yields. The reaction of lactol 3a under the same reaction conditions proceeds with formation of the 1′,5′-anhydro derivative 7 via competing intramolecular substitution. 相似文献
77.
Jorge R. Toledo Yanet Prieto Nayrobis Oramas Oliberto Sánchez 《Applied biochemistry and biotechnology》2009,157(3):538-544
HIV-1-derived lentiviral vectors (LvV) are within the most attractive gene delivery vehicles in the context of both dividing
and quiescent cells. LvV is currently produced by the conventional calcium phosphate precipitation method. Nevertheless, this
procedure is highly susceptible to variations in pH and impurities, which lead to inconsistencies in LvV production. Here,
we present a simple and robust procedure for LvV production using branched 25 kDa polyethylenimine, with a transfection efficiency
of over 90% and viral titer yields of about 1 × 107 infective lentiviral particles per milliliter. The procedure outlined is simple, consistent, and as inexpensive as the CaPO4-based method. 相似文献
78.
Piñeiro A Prieto G Ruso JM Verdes PV Sarmiento F 《Journal of colloid and interface science》2009,329(2):351-356
Using grazing incidence small-angle X-ray scattering (GISAXS), and atomic force microscopy (AFM) it has been recently demonstrated that linear fluorocarbon-hydrocarbon diblocks (FnHm) self-assemble in water/air interfaces forming elongated and circular hemimicelles. Those structures have been observed for diblocks with at least eight fluorinated carbons. Based on the lack of a collapse pressure for F6H16, and due to the fact that no stable surface pressure values are reached under compression, it has been concluded that these molecules do not form stable monolayers. It has been also suggested that F6H16 and shorter diblocks desorb from the water surface under compression. It is not easy to accept that a significant concentration of so hydrophobic molecules can be stable in aqueous solution even when the employed experimental techniques were not able to clearly detect a well defined structure on the interface. In the present work the adsorption and arrangement of F6H16 and F6H10 at the water surface are studied by molecular dynamics (MD) simulations as a function of the available area per molecule. Starting from a random mixture, the spontaneous formation of elongated hemimicelles is observed for both systems when the area per molecule is higher than approximately 50 A(2). For intermediate areas two pseudo-phases, one rich in hydrocarbons and the other with higher fluorocarbon concentration, are formed. For the systems with less than approximately 30 A(2) available per molecule the formation of multilayers is observed. This is the first time that the dynamics and structure of perfluoroalkane (PFA) films, and in particular of hemimicelles on a liquid surface, are observed and characterized at atomic level. 相似文献
79.
Brandes S Niess B Bella M Prieto A Overgaard J Jørgensen KA 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(23):6039-6052
A new class of 6'-hydroxy cinchona alkaloids, with a non-biaryl atropisomeric functionalisation at position 5' of the quinoline core can be prepared by an easy amination procedure. These are the first derivatives for which the principle of atropisomerism is engrafted in the classical core of the cinchona alkaloids. The aminated cinchona alkaloids are effective organocatalysts for the Michael addition of beta-keto esters to acrolein and methyl vinyl ketone, in up to 93 % ee (ee=enantiomeric excess), as well as for the asymmetric Friedel-Crafts amination of a variety of 2-naphthols, permitting the preparation of the latter in up to 98 % ee. The aminated 8-amino-2-naphthol itself is the first chiral organocatalyst based on non-biaryl atropisomerism. The two enantiomers of this chiral primary amine can be used for the direct alpha-fluorination of alpha-branched aldehydes. The fluorinated compounds can thereby be accessed in up to 90 % ee. 相似文献
80.
Hindered protected and unprotected epoxy alcohols were regioselectively cleaved using copper-catalyzed cis- and trans-1-propenylmagnesium bromide. The reaction exhibited good yield and excellent regioselectivity in systems where organocuprates and organoalanes failed. The cis Grignard reagent displayed no double-bond isomerization, whereas the trans isomer showed partial trans-to-cis equilibration, which was minimized by controlling the reagent formation conditions. The reaction was shown to be highly useful for the elaboration of the C10-C15 Streptovaricin D ansa chain fragment. 相似文献