El lenguaje clásico es atemporal. Entrevista a David Watkin

Watkin se ha distinguido como uno de los más certeros y sobrios polemistas y críticos arquitectónicos, como lo demuestra su celebérrimo ensayo Morality and Architecture (1977), una de las pocas obras imprescindibles en el debate arquitectónico del siglo XX, así como el gran numero de actos y campañas desarrolladas por él en defensa de la supervivencia de la tradición arquitectónica clásica y en solidaridad con los arriesgados arquitectos que hoy en día la representan. Esta faceta pública ha llevado a Watkin a las fronteras de la política y lo ha situado en el centro de un convulso debate público que aún se halla en pleno desarrollo, rodeando cada una de las obras de arquitectos estrella que se levantan en Inglaterra

The application of inelastic neutron scattering to investigate the interaction of methyl propanoate with silica

A modern industrial route for the manufacture of methyl methacrylate involves the reaction of methyl propanoate and formaldehyde over a silica-supported Cs catalyst. Although the process has been successfully commercialised, little is known about the surface interactions responsible for the forward chemistry. This work concentrates upon the interaction of methyl propanoate over a representative silica. A combination of infrared spectroscopy, inelastic neutron scattering, DFT calculations, X-ray diffraction and temperature-programmed desorption is used to deduce how the ester interacts with the silica surface

Interaction of UVA (320-380 nm) radiation with human skin cells

The generation of reactive oxygen species (ROS) by UVA radiation (320-380 nm) is responsible for damage to intracellular biological macromolecules, cytotoxicity and many other effects. Both the endogenous chromophore protoporphyrin IX (PPIX) and 'free' iron are potentially important sources of ROS after UVA irradiation in human cells. The aim of this study was to determine the importance of PPIX in the inactivation of human cells after UVA irradiation, and to determine what effect UVA irradiation had on intracellular 'free' iron levels. By modulating levels of the intracellular chromophore PPIX in human cells by exogenous administration of the haem precursor #delta#-aminolevulinic acid (ALA) and irradiating these cells with graded doses of UVA, it was determined that the basal content of PPIX in TK6 human lymphoblastoid cells is insufficient to make a significant contribution to the UVA-mediated inactivation of these cells. The basal content of PPIX was however found to make a significant contribution to LTVA-mediated inactivation of the primary human fibroblast cell line, FEK4, which implicates PPIX as a critical UVA chromophore in this cell line. We document in this study the development of a flow cytometry-based fluorescence assay system that is capable of determining membrane damage and changes in intracellular 'free' iron levels. By using this assay and the cytoplasmic aconitase assay, we have confirmed that UVA irradiation of human skin cells results in an increase in intracellular 'free' iron levels. We also demonstrate that while administration of ALA to FEK4 cells does lower the intracellular 'free' iron levels, this type of treatment strongly exacerbates the increase in 'free' iron levels observed after UVA irradiation. The effects of ALA treatment and UVA irradiation on ferritin levels in FEK4 cells was also determined in this study using a polyclonal (anti-ferritin) antibody enzyme-linked immunosorbent assay. We demonstrate in this study that UVA irradiation of cells, and to a much greater extent, UVA irradiation of cells treated with ALA, results in the degradation of ferritin. This provides strong evidence for ferritin being a major source of the increase in intracellular 'free' iron levels observed after such treatments. It is hoped that data obtained from this study will contribute to an advancement in the understanding of the intracellular effects of UVA irradiation and that this may help in the protection against, and prevention of, processes such as UVA-induced photocarcinogenesis and photoageing. (author)Available from British Library Document Supply Centre-DSC:DXN032872 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

(S)-3-Dimethyl­amino-2-{(4S,5R)-5-[(R)-2,2-dimethyl-1,3-dioxolan-4-yl]-2,2-dimethyl-1,3-dioxolan-4-yl}-2-hydroxy­propanoic acid

The Kiliani reaction on 1-de­oxy-(N,N-dimethyl­amino)-d-fructose, itself readily available from reaction of dimethyl­amine and d-glucose, proceeded to give access to the title β-sugar amino acid, C15H27NO7. X-ray crystallography determined the stereochemistry at the newly formed chiral center. There are two mol­ecules in the asymmetric unit; they are related by a pseudo-twofold rotation axis and have very similar geometries, differing only in the conformation of one of the acetonide rings. All the acetonide rings adopt envelope conformations; the flap atom is oxygen in three of the rings, but carbon in one of them. There are two strong hydrogen bonds between the two independent mol­ecules, and further weak hydrogen bonds link the mol­ecules to form infinite chains running parallel to the a axis

α-d-Tagatopyran­ose

The title compound, C6H12O6, also known as d-Tagatose, occurs in its furanose and pyranose forms in solution, but only the α-pyran­ose form crystallizes out. In the crystal, the molecules form hydrogen bonded chains propagating in [100] linked by O—H⋯O interactions. Further O—H⋯O bonds cross-link the chains

3-O-Benzhydryl-2,5-dide­oxy-2,5-imino-2-C-methyl-l-lyxono-1,4-lactone

The title bicyclic lactone, C19H19NO3, is an inter­mediate in the synthesis of chiral α-methyl­prolines and branched C-methyl pyrrolidines; the absolute configuration was determined by the use of d-erythronolactone as the starting material. It exhibits no unusual crystal packing features, and each mol­ecule acts as a donor and acceptor for one C—H⋯O hydrogen bond

2-De­oxy-2,3-O-isopropyl­idene-2,4-di-C-methyl-β-l-arabinose

X-ray crystallography unequivocally confirmed the stereochemistry of the C atom at position 2 in the carbon scaffold of the title mol­ecule, C10H18O4. The pyran­ose ring exists in a chair conformation with the methyl group on the C atom in the 2 position in an equatorial configuration. The absolute stereochemistry was determined from the starting material. The crystal structure consists of O—H⋯O hydrogen-bonded chains of mol­ecules running parallel to the b axis

2,3-O-(S)-Benzyl­idene-2-C-methyl-d-ribono-1,4-lactone

The crystal structure of the title compound, C13H14O5, establishes (i) the (S) – rather than (R) – configuration at the acetal carbon and (ii) that both the acetal and the lactone form five- rather than six-membered rings; the absolute configuration is determined by the use of 2-C-methyl-d-ribono-1,4-lactone as the starting material. The compound consists of hydrogen-bonded chains of mol­ecules running along the a axis; there are no unusual packing features. Only classical hydrogen bonding has been considered

Benzyl N0-[1-(3-pyridyl)ethylidene]-hydrazinecarbodithioate

The title compound, C15H5N2S2, crystallizes as a trans–cis conformer. The thione sulfur is in a trans position with the methyl pyridyl fragment with respect to the C—N bond but adopts a cis position with the benzyl ring across the C—S bond. The dihedral angle between the planar quinoline ring and the dithiocarbazate unit is 103.70 (1). The inclination of the dithiocarbazate unit with the benzyl group is 17.20 (1).There are strong – stacking interactions between pairs of dithiocarbazate units and also pairs of pyridine rings [3.27 (5)and 3.28 (5) A ° , respectively]. A long-distance intermolecular N—H N hydrogen bond [3.171 (2) A ° ] also stabilizes the structure

2-Quinolylmethyl N0-[1-(m-tolyl) ethylidene] hydrazinecarbodithioate

The title compound, C20H19N3S2, crystallized as a cis–trans conformer in which the quinoline ring system is cis across the C—S bond but adopts a trans geometry with respect to the C—N bond. The compound exists in the thione form with the presence of a C S bond