982 resultados para Rolf de Heer
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Este artículo analiza la imagen de la Ciudad de México configurada en la crónica mexicana a partir de los años setenta en especial en los textos de José Joaquín Blanco. Se detiene en el modo en que el género afronta la realidad de una megalópolis que ya solo puede ser asumida de modo fragmentario y múltiple. Entre la utopía y una visión apocalíptica de la ciudad, la crónica reconfigura el espacio y el tiempo urbanos, y formula una nueva identidad crítica gracias a la habilitación de espacios de expresión posibles dentro de las nuevas ciudades modificadas por el capital.
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Three Entries: Peacelines; Public Housing in Northern Ireland in the Twentieth Century; Interpretive Centres, NI Peacelines, NI Social Housing
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El Jardí del Set Crepuscles –primera novela del escritor y arquitecto catalán Miquel de Palol– nos brinda la oportunidad de reflexionar acerca de la metamorfosis experimentada por la ciudad occidental a principios de los años setenta del siglo pasado. De acuerdo con autores como Henri Lefebvre, David Harvey, Giandomenico Amendola o Edward Soja, el surgimiento de la ciudad posmoderna en el marco de la transición hacia el modo de acumulación postfordista se presenta acompañado por un debilitamiento del tejido social y de la esfera pública y cívica. El objetivo del presente artículo es ilustrar las estrategias narrativas y retóricas con las que el texto de Miquel de Palol representa, y analiza, dicho fenómeno.
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Mitochondrial transcription termination factor 1, MTERF1, has been reported to couple rRNA gene transcription initiation with termination and is therefore thought to be a key regulator of mammalian mitochondrial ribosome biogenesis. The prevailing model is based on a series of observations published over the last two decades, but no in vivo evidence exists to show that MTERF1 regulates transcription of the heavy-strand region of mtDNA containing the rRNA genes. Here, we demonstrate that knockout of Mterf1 in mice has no effect on mitochondrial rRNA levels or mitochondrial translation. Instead, loss of Mterf1 influences transcription initiation at the light-strand promoter, resulting in a decrease of de novo transcription manifested as reduced 7S RNA levels. Based on these observations, we suggest that MTERF1 does not regulate heavy-strand transcription, but rather acts to block transcription on the opposite strand of mtDNA to prevent transcription interference at the light-strand promoter.
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Super-luminous supernovae have a tendency to occur in faint host galaxies which are likely to have low mass and low metallicity. While these extremely luminous explosions have been observed from z=0.1 to 1.55, the closest explosions allow more detailed investigations of their host galaxies. We present a detailed analysis of the host galaxy of SN 2010gx (z=0.23), one of the best studied super-luminous type Ic supernovae. The host is a dwarf galaxy (M_g=-17.42+/-0.17) with a high specific star formation rate. It has a remarkably low metallicity of 12+log(O/H)=7.5+/-0.1 dex as determined from the detection of the [OIII] 4363 Angs line. This is the first reliable metallicity determination of a super-luminous stripped-envelope supernova host. We collected deep multi-epoch imaging with Gemini + GMOS between 240-560 days after explosion to search for any sign of radioactive nickel-56, which might provide further insights on the explosion mechanism and the progenitor's nature. We reach griz magnitudes of m_AB~26, but do not detect SN 2010gx at these epochs. The limit implies that any nickel-56 production was similar to or below that of SN 1998bw (a luminous type Ic SN that produced around 0.4 M_sun of nickel-56). The low volumetric rates of these supernovae (~10^-4 of the core-collapse population) could be qualitatively matched if the explosion mechanism requires a combination of low-metallicity (below 0.2 Z_sun), high progenitor mass (>60 M_sun) and high rotation rate (fastest 10% of rotators).
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Objective: To investigate the association between serum 25-hydroxyvitamin D concentrations (25(OH)D) and mortality in a large consortium of cohort studies paying particular attention to potential age, sex, season, and country differences.
Design: Meta-analysis of individual participant data of eight prospective cohort studies from Europe and the US.
Setting: General population.
Participants: 26 018 men and women aged 50-79 years
Main outcome measures: All-cause, cardiovascular, and cancer mortality.
Results: 25(OH)D concentrations varied strongly by season (higher in summer), country (higher in US and northern Europe) and sex (higher in men), but no consistent trend with age was observed. During follow-up, 6695 study participants died, among whom 2624 died of cardiovascular diseases and 2227 died of cancer. For each cohort and analysis, 25(OH)D quintiles were defined with cohort and subgroup specific cut-off values. Comparing bottom versus top quintiles resulted in a pooled risk ratio of 1.57 (95% CI 1.36 to 1.81) for all-cause mortality. Risk ratios for cardiovascular mortality were similar in magnitude to that for all-cause mortality in subjects both with and without a history of cardiovascular disease at baseline. With respect to cancer mortality, an association was only observed among subjects with a history of cancer (risk ratio, 1.70 (1.00 to 2.88)). Analyses using all quintiles suggest curvilinear, inverse, dose-response curves for the aforementioned relationships. No strong age, sex, season, or country specific differences were detected. Heterogeneity was low in most meta-analyses.
Conclusions: Despite levels of 25(OH)D strongly varying with country, sex, and season, the association between 25(OH)D level and all-cause and cause-specific mortality was remarkably consistent. Results from a long term randomised controlled trial addressing longevity are being awaited before vitamin D supplementation can be recommended in most individuals with low 25(OH)D levels.
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A better understanding of events triggering chronic myeloid leukemia progression are critical to optimised clinical management of chronic myeloid leukemia (CML). We sought to validate that increased Musashi 2 (MSI2), a post transcription regulator, expression is associated with progression and prognosis. Screening of 152 CML patients showed MSI2 was significantly decreased among CML patients in CP at diagnosis (p<0.0001), but found no significant difference between the normal control group and treated CML patients in CP. Moreover it was significantly increased (p<0.0001) in advance disease (AD) CML patients. Furthermore, our human hematopoietic cell line data imply MSI2 and BCR-ABL1 mRNA expression correlate. However, these data cast a doubt on earlier reports that MSI2 effects HES1 expression via NUMB-NOTCH signaling.
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This work aimed to evaluate whether ETS transcription factors frequently involved in rearrangements in prostate carcinomas (PCa), namely ERG and ETV1, regulate specific or shared target genes. We performed differential expression analysis on nine normal prostate tissues and 50 PCa enriched for different ETS rearrangements using exon-level expression microarrays, followed by in vitro validation using cell line models. We found specific deregulation of 57 genes in ERG-positive PCa and 15 genes in ETV1-positive PCa, whereas deregulation of 27 genes was shared in both tumor subtypes. We further showed that the expression of seven tumor-associated ERG target genes (PLA1A, CACNA1D, ATP8A2, HLA-DMB, PDE3B, TDRD1, and TMBIM1) and two tumor-associated ETV1 target genes (FKBP10 and GLYATL2) was significantly affected by specific ETS silencing in VCaP and LNCaP cell line models, respectively, whereas the expression of three candidate ERG and ETV1 shared targets (GRPR, KCNH8, and TMEM45B) was significantly affected by silencing of either ETS. Interestingly, we demonstrate that the expression of TDRD1, the topmost overexpressed gene of our list of ERG-specific candidate targets, is inversely correlated with the methylation levels of a CpG island found at -66 bp of the transcription start site in PCa and that TDRD1 expression is regulated by direct binding of ERG to the CpG island in VCaP cells. We conclude that ETS transcription factors regulate specific and shared target genes and that TDRD1, FKBP10, and GRPR are promising therapeutic targets and can serve as diagnostic markers for molecular subtypes of PCa harboring specific fusion gene rearrangements.
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Patterns of glycosylation are important in cancer, but the molecular mechanisms that drive changes are often poorly understood. The androgen receptor drives prostate cancer (PCa) development and progression to lethal metastatic castration-resistant disease. Here we used RNA-Seq coupled with bioinformatic analyses of androgen-receptor (AR) binding sites and clinical PCa expression array data to identify ST6GalNAc1 as a direct and rapidly activated target gene of the AR in PCa cells. ST6GalNAc1 encodes a sialytransferase that catalyses formation of the cancer-associated sialyl-Tn antigen (sTn), which we find is also induced by androgen exposure. Androgens induce expression of a novel splice variant of the ST6GalNAc1 protein in PCa cells. This splice variant encodes a shorter protein isoform that is still fully functional as a sialyltransferase and able to induce expression of the sTn-antigen. Surprisingly, given its high expression in tumours, stable expression of ST6GalNAc1 in PCa cells reduced formation of stable tumours in mice, reduced cell adhesion and induced a switch towards a more mesenchymal-like cell phenotype in vitro. ST6GalNAc1 has a dynamic expression pattern in clinical datasets, beingsignificantly up-regulated in primary prostate carcinoma but relatively down-regulated in established metastatic tissue. ST6GalNAc1 is frequently upregulated concurrently with another important glycosylation enzyme GCNT1 previously associated with prostate cancer progression and implicated in Sialyl Lewis X antigen synthesis. Together our data establishes an androgen-dependent mechanism for sTn antigen expression in PCa, and are consistent with a general role for the androgen receptor in driving important coordinate changes to the glycoproteome during PCa progression.