El color en el siglo XIX: utilización de fondos de colores oscuros en los revestimientos de paramentos interiores en la arquitectura del siglo XIX

El Color en el Siglo XIX: Utilización de Fondos de Colores Oscuros en los Revestimientos de Paramentos Interiores en la Arquitectura del Siglo XIX De los elementos del pasado el color es el que más rápidamente cambia y se deteriora, por lo que no podemos saber las condiciones originales de color e iluminación en los interiores que han llegado hasta nosotros. Frecuentemente nos enfrentamos a los problemas que plantean los espacios del pasado, proyectando nuestros propios criterios sobre color y luz, que no tienen que coincidir necesariamente con los criterios de épocas anteriores. En las hermosas láminas del libro de Cesar Daly ?Décorations intérieures: peintes? de 1877, observamos que los colores que decoran las paredes son sorprendentemente oscuros. La oscuridad de estos muros es más sorprendente si pensamos en la débil luz de llama que iluminaba las salas en esa época, muy inferior a los niveles de luz que nos proporciona la luz eléctrica hoy en día. No obstante, esta débil iluminación sobre paredes de tonos oscuros puede tener alguna ventaja. Las paredes y las líneas de la habitación se difuminan en las sombras, mientras los objetos brillantes que decoran la habitación, como los cuadros, los barnices de los muebles y de los instrumentos musicales, y sobre todo los trajes y los rostros, reflejan la tenue luz, destacando sobre el fondo oscuro de las paredes, convirtiéndose en el centro de una escenografía. Es lo que Lewis Mumford en su Libro ?Técnica y civilización?, llama la ?ventaja estética? del mundo oscuro de la Revolución Industrial, dominado por el uso del carbón, que contamina el ambiente, transforma el color de los edificios y produce nieblas que atenúan la luz. En este mundo, según este autor, se acrecienta la sensibilidad por la luz, y se valora como un bien preciado la luz tenue que brilla entre la niebla que disuelve los objetos, lo que podemos observar en cuadros como el de ?Lluvia, vapor y velocidad? de Turner, o ?Impressión: soleil levant? de Monet. La importancia de los fondos de color oscuro se hace evidente al comprobar cómo los diseñadores de vanguardia del siglo XX para superar el mundo caduco del XIX deciden pintar de blanco las superficies, lo que se convierte en el signo de la modernidad.

Plasma kinetics issues in an ESA study for a plasma laboratory in space

A study supported by the European Space Agency (ESA), in the context of its General Studies Programme, performed an investigation of the possible use of space for studies in pure and applied plasma physics, in areas not traditionally covered by ‘space plasma physics’. A set of experiments have been identified that can potentially provide access to new phenomena and to allow advances in several fields of plasma science. These experiments concern phenomena on a spatial scale (101–104 m) intermediate between what is achievable on the ground and the usual solar system plasma observations. Detailed feasibility studies have been performed for three experiments: active magnetic experiments, largescale discharges and long tether–plasma interactions. The perspectives opened by these experiments are discussed for magnetic reconnection, instabilities, MHD turbulence, atomic excited states kinetics, weakly ionized plasmas,plasma diagnostics, artificial auroras and atmospheric studies. The discussion is also supported by results of numerical simulations and estimates.

The ESA "Plasma Laboratory in Space" study

The European Space Agency has initiated, in the context of its General Studies Programme, a study of the possible use of space for studies in pure and applied plasma physics, in areas not traditionally covered by “space plasma physics”. A team of experts has been set-up to review a broad range of area including industrial plasma physics and pure plasma physics, astrophysical and solar-terrestrial areas. A set of experiments have been identified that can potentially provide access to new phenomena and to allow advances in several fields of plasma science. These experiments concern phenomena on spatial scale (102 to104 m) intermediate between what is achievable on ground experiment and usual solar system plasma observations.

Accumulation of premutagenic DNA lesions in mice defective in removal of oxidative base damage

DNA damage generated by oxidant byproducts of cellular metabolism has been proposed as a key factor in cancer and aging. Oxygen free radicals cause predominantly base damage in DNA, and the most frequent mutagenic base lesion is 7,8-dihydro-8-oxoguanine (8-oxoG). This altered base can pair with A as well as C residues, leading to a greatly increased frequency of spontaneous G·C→T·A transversion mutations in repair-deficient bacterial and yeast cells. Eukaryotic cells use a specific DNA glycosylase, the product of the OGG1 gene, to excise 8-oxoG from DNA. To assess the role of the mammalian enzyme in repair of DNA damage and prevention of carcinogenesis, we have generated homozygous ogg1−/− null mice. These animals are viable but accumulate abnormal levels of 8-oxoG in their genomes. Despite this increase in potentially miscoding DNA lesions, OGG1-deficient mice exhibit only a moderately, but significantly, elevated spontaneous mutation rate in nonproliferative tissues, do not develop malignancies, and show no marked pathological changes. Extracts of ogg1 null mouse tissues cannot excise the damaged base, but there is significant slow removal in vivo from proliferating cells. These findings suggest that in the absence of the DNA glycosylase, and in apparent contrast to bacterial and yeast cells, an alternative repair pathway functions to minimize the effects of an increased load of 8-oxoG in the genome and maintain a low endogenous mutation frequency.

Loperamide: A positive modulator for store-operated calcium channels?

The depletion of inositol trisphosphate-sensitive intracellular pools of calcium causes activation of store-operated calcium (SOC) channels. Loperamide at 10–30 μM has no effect on intracellular calcium levels alone, but augments calcium levels in cultured cells when SOC channels have been activated. In HL-60 leukemic cells, the apparent positive modulatory effect of loperamide on SOC channels occurs when these channels have been activated after ATP, thapsigargin, or ionomycin-elicited depletion of calcium from intracellular storage sites. Loperamide has no effect when levels of intracellular calcium are elevated through a mechanism not involving SOC channels by using sphingosine. Loperamide caused augmentation of intracellular calcium levels after activation of SOC channels in NIH 3T3 fibroblasts, astrocytoma 1321N cells, smooth muscle DDT-MF2 cells, RBL-2H3 mast cells, and pituitary GH4C1 cells. Only in astrocytoma cells did loperamide cause an elevation in intracellular calcium in the absence of activation of SOC channels. The augmentation of intracellular calcium elicited by loperamide in cultured cells was dependent on extracellular calcium and was somewhat resistant to agents (SKF 96365, miconazole, clotrimazole, nitrendipine, and trifluoperazine) that in the absence of loperamide effectively blocked SOC channels. It appears that loperamide augments influx of calcium through activated SOC channels.

Neonatal gene transfer leads to widespread correction of pathology in a murine model of lysosomal storage disease

For many inborn errors of metabolism, early treatment is critical to prevent long-term developmental sequelae. We have used a gene-therapy approach to demonstrate this concept in a murine model of mucopolysaccharidosis type VII (MPS VII). Newborn MPS VII mice received a single intravenous injection with 5.4 × 106 infectious units of recombinant adeno-associated virus encoding the human β-glucuronidase (GUSB) cDNA. Therapeutic levels of GUSB expression were achieved by 1 week of age in liver, heart, lung, spleen, kidney, brain, and retina. GUSB expression persisted in most organs for the 16-week duration of the study at levels sufficient to either reduce or prevent completely lysosomal storage. Of particular significance, neurons, microglia, and meninges of the central nervous system were virtually cleared of disease. In addition, neonatal treatment of MPS VII mice provided access to the central nervous system via an intravenous route, avoiding a more invasive procedure later in life. These data suggest that gene transfer mediated by adeno-associated virus can achieve therapeutically relevant levels of enzyme very early in life and that the rapid growth and differentiation of tissues does not limit long-term expression.

Batrachotoxin alkaloids from passerine birds: A second toxic bird genus (Ifrita kowaldi) from New Guinea

Batrachotoxins, including many congeners not previously described, were detected, and relative amounts were measured by using HPLC-mass spectrometry, in five species of New Guinean birds of the genus Pitohui as well as a species of a second toxic bird genus, Ifrita kowaldi. The alkaloids, identified in feathers and skin, were batrachotoxinin-A cis-crotonate (1), an allylically rearranged 16-acetate (2), which can form from 1 by sigmatropic rearrangement under basic conditions, batrachotoxinin-A and an isomer (3 and 3a, respectively), batrachotoxin (4), batrachotoxinin-A 3′-hydroxypentanoate (5), homobatrachotoxin (6), and mono- and dihydroxylated derivatives of homobatrachotoxin. The highest levels of batrachotoxins were generally present in the contour feathers of belly, breast, or legs in Pitohui dichrous, Pitohui kirhocephalus, and Ifrita kowaldi. Lesser amounts are found in head, back, tail, and wing feathers. Batrachotoxin (4) and homobatrachotoxin (6) were found only in feathers and not in skin. The levels of batrachotoxins varied widely for different populations of Pitohui and Ifrita, a result compatible with the hypothesis that these birds are sequestering toxins from a dietary source.

Short tandem repeat profiling provides an international reference standard for human cell lines

Cross-contamination between cell lines is a longstanding and frequent cause of scientific misrepresentation. Estimates from national testing services indicate that up to 36% of cell lines are of a different origin or species to that claimed. To test a standard method of cell line authentication, 253 human cell lines from banks and research institutes worldwide were analyzed by short tandem repeat profiling. The short tandem repeat profile is a simple numerical code that is reproducible between laboratories, is inexpensive, and can provide an international reference standard for every cell line. If DNA profiling of cell lines is accepted and demanded internationally, scientific misrepresentation because of cross-contamination can be largely eliminated.

Genetic mapping of a murine locus controlling development of T helper 1/T helper 2 type responses.

Genetic background of the T cell can influence T helper (Th) phenotype development, with some murine strains (e.g., B10.D2) favoring Th1 development and others (e.g., BALB/c) favoring Th2 development. Recently we found that B10.D2 exhibit an intrinsically greater capacity to maintain interleukin 12 (IL-12) responsiveness under neutral conditions in vitro compared with BALB/c T cells, allowing for prolonged capacity to undergo IL-12-induced Th1 development. To begin identification of the loci controlling this genetic effect, we used a T-cell antigen receptor-transgenic system for in vitro analysis of intercrosses between BALB/c and B10.D2 mice and have identified a locus on murine chromosome 11 that controls the maintenance of IL-12 responsiveness, and therefore the subsequent Th1/Th2 response. This chromosomal region is syntenic with a locus on human chromosome 5q31.1 shown to be associated with elevated serum IgE levels, suggesting that genetic control of Th1/Th2 differentiation in mouse, and of atopy development in humans, may be expressed through similar mechanisms.

Three-dimensional structure of a cysteine-rich repeat from the low-density lipoprotein receptor.

The low-density lipoprotein (LDL) receptor plays a central role in mammalian cholesterol metabolism, clearing lipoproteins which bear apolipoproteins E and B-100 from plasma. Mutations in this molecule are associated with familial hypercholesterolemia, a condition which leads to an elevated plasma cholesterol concentration and accelerated atherosclerosis. The N-terminal segment of the LDL receptor contains a heptad of cysteine-rich repeats that bind the lipoproteins. Similar repeats are present in related receptors, including the very low-density lipoprotein receptor and the LDL receptor-related protein/alpha 2-macroglobulin receptor, and in proteins which are functionally unrelated, such as the C9 component of complement. The first repeat of the human LDL receptor has been expressed in Escherichia coli as a glutathione S-transferase fusion protein, and the cleaved and purified receptor module has been shown to fold to a single, fully oxidized form that is recognized by the monoclonal antibody IgG-C7 in the presence of calcium ions. The three-dimensional structure of this module has been determined by two-dimensional NMR spectroscopy and shown to consist of a beta-hairpin structure, followed by a series of beta turns. Many of the side chains of the acidic residues, including the highly conserved Ser-Asp-Glu triad, are clustered on one face of the module. To our knowledge, this structure has not previously been described in any other protein and may represent a structural paradigm both for the other modules in the LDL receptor and for the homologous domains of several other proteins. Calcium ions had only minor effects on the CD spectrum and no effect on the 1H NMR spectrum of the repeat, suggesting that they induce no significant conformational change.

Carbonatito de Jacupiranga, Estado de São Paulo

O distrito magmático alcalino de Jacupiranga constitui a ocorrência brasileira clássica de rochas alcalinas e ultrabásicas. Mencionado pela primeira vez por Bauer (1877) como jazida de minério de ferro, tornou-se conhecido através da descrição de Derby (1891), que propôs o termo jacupiranguito para as rochas alcalinas piroxeníticas aí correntes. Na mesma época, Hussak (1892, 1895, 1904) publicou descrições de minerais associados ao minério de ferro. Numerosas referências a Jacupiranga são encontradas na literatura especializada e de acordo com as preferências dos diversos autores e as tendências de cada época, o distrito foi citado como exemplo das mais variadas teorias petrogenéticas, principalmente da hipótese de Daly e Shand. Entretanto, a região nunca foi objeto de investigação realmente minuciosa. Por várias razões justifica-se um enxame e a descrição detalhada do carbonatito de Jacupiranga. Sob ponto de vista petrológico, as concepções sobre a gênese de rochas carbonáticas associadas a alcalinas evoluíram consideravelmente nos últimos anos. Numerosos estudos tendem a demonstrar o caráter magmático desses carbonatos, porém muitas de suas feições ainda permanecem sem explicação satisfatória. A descrição da localidade em questão visa contribuir para o acúmulo de observações necessárias à elaboração de hipóteses petrogenéticas, embora o estudo atual de nossos conhecimentos sobre a evolução dos magmas alcalinos ainda não permite a formulação de interpretações definitivas. Sob o ponto de vista industrial e econômico, um levantamento exato do carbonatito e dos minerais a ele associados é essencial. A interpretação correta da origem dos fosfatos residuais permite sua pesquisa e lavra racionais. Além disso, ocorre vultuosa reserva de carbonato de cálcio, fosfatos, óxidos de ferro e de titânio. O aproveitamento dessas matérias primas depende de sua caracterização geológica e mineralógica, tanto para a comprovação ) de toneladas exploráveis, como para o desenvolvimento de processos tecnológicos de concentração. No presente trabalho são apresentadas, as observações que pareceram de maior interesse geológico e econômico. Durante vários anos o autor teve oportunidade de realizar numerosas visitas à jazida de Jacupiranga e acompanhar o seu desenvolvimento. Recentemente, a lavra do minério residual e eluvial permitiu observações mais detalhadas do calcário não meteorizado, revelando sua extensão e riqueza em apatita. Pareceu então justificado sugerir à SERRANA SOCIEDADE ANÔNIMA DE MINERAÇÃO, concessionária do depósito, uma pesquisa preliminar da massa de carbonatito. Esse trabalho vem sendo executado de acordo com as recomendações do autor e consta de um levantamento a prancheta em escala 1:500 com intervalo de 1 metro entre curvas de níquel, coleta de aproximadamente 400 amostras na superfície do carbonatito, abertura de galerias de pesquisa e sondagens. Muitas centenas de análises químicas permitem a determinação exata dos teores dos principais elementos constituintes. Para os estudos mineralógicos foi examinada uma centena de lâminas delgadas e o resíduo insolúvel de 200 amostras de calcário. A granulação e a textura da rocha foi observada em algumas dezenas de amostras coloridas diferencialmente. Numerosos ensaios de cominuição, determinação dos teores nas frações granulométricas, de separação magnética e por líquidos pesados foram ainda realizados para a obtenção de elementos necessários aos estudos sobre processos de concentração industrial de apatita. Embora a pesquisa ainda não esteja concluída, seus resultados parciais são promissores. Verificou-se a existência de concentrações de apatita com dimensões de muitas dezenas de metros e teores acima de 15% de fosfato. Comprovou-se ainda grande tonelagem de calcário praticamente isento de sílica, com teor de magnésia inferior a 1.5%. Simultaneamente, as informações obtidas através dessa pesquisa permitem a caracterização da constituição química e litológica do carbonatito com precisão provavelmente superior à de qualquer ocorrência congênere.

San Francisco Peninsula, California 1869 (Raster Image)

This layer is a georeferenced raster image of the historic topographic paper map entitled: San Francisco Peninsula, U.S. Coast Survey ; Benjamin Peirce, superintendent ; verified J.E. Hilgard. It was published by Coast Survey Office in 1869. Scale 1:40,000. The image inside the map neatline is georeferenced to the surface of the earth and fit to the California Zone III State Plane Coordinate System NAD83 (in Feet) (Fipszone 0403). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This is a typical topographic map portraying both natural and manmade features. It shows and names works of nature, such as mountains, valleys, lakes, rivers, vegetation, etc. It also identify the principal works of humans, such as roads, railroads, boundaries, transmission lines, major buildings, etc. Relief is shown with standard contour intervals of 20 feet and spot heights. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.