The Kinematics of the Ionized and Molecular Hydrogen in the Starburst Galaxy NGC 253

Near-infrared H_2 1-0 S(1) and Br_gamma velocity curves along the major axis of NGC 253 have revealed a central velocity gradient that is seven times steeper than that shown by the optical velocity curve. This is interpreted as an optical depth effect due to dust. Approximately 35 mag of visual extinction in the center is required to match the SW side of the optical velocity curve. The spatial variation of the ratio of these lines to the CO (J=1-0) line is compared among starburst galaxies NGC 253, M82, and NGC 4945 to investigate the excitation mechanism responsible for the H_2 1-0 S(1) line.Comment: Uuencoded postscript file, 10 pages (4 tables included), 8 figures available on request to [email protected], Ap.J. (in press

A evolução tectonotermal proterozóica do cráton do São Francisco, com base em interpretações geocronológicas K-Ar em rochas do seu embasamento

The geochronologic data base for the São Francisco Craton (SFC) includes more than 400 K-Ar age determinations. The K-Ar ages on crystalline basement rocks characterize regional cooling patterns within the SFC, that permit definition of its tectonothermal history during the Proterozoic. This history is also substantiated by the crustal evolution postulated for the SFC and by the U-Pb, Rb-Sr, Pb-Pb, Sm-Nd) data including that of its adjacent Neoproterozoic fold belts. Regional cooling of large domains of the SFC occurred mostly during the Transamazonian cycle as a result of progressive uplift accompanying the tectonic stability of the Itabuna, Correntina-Guanambi and Mineiro belts, around 2,1 - 1,8 Ga ago. The 1,72 - 1,65 Ga age pattern identified in sectors of the Itabuna (Salvador region) and Mineiro belts (west of Belo Horizonte) suggests a relationship with the geodynamics associated with the extensional collapse of the Espinhaço rift originated at ca. L75 Ga ago. The 0,80/0,65 Ga and 0,65/0,50 Ga age intervals are characteristic for the basement rocks located at the borders of the SFC and in the Paramirim province. These patterns may have a tectonic link with the collision processes against the SFC, of the marginal Neoproterozoic belts. In special, the K-Ar resetting in the Paramirim province accompanied deformation and metamorphic overprint of the crystalline basement, probably in association with the collision of the Rio Preto and Araçuaí belts. As a whole, the K-Ar age patterns coupled with the geologic and structural scenario and the crustal evolution of the SFC reveal it consists a foreland unit for the surrounding tectonics that took place in eastern Brazil, during the Neoproterozoic. Nevertheless, the basement rocks located in the southeast and east borders of the SFC and in the Paramirim province have been reactivated due to the Brasiliano cycle evolution marginal to the craton.Mais de 400 datações K-Ar compõem o banco de dados radiométricos do Cráton do São Francisco (CSF). A partir da análise das idades K-Ar em rochas da infraestrutura (cerca de 65% dos dados), e tendo em vista o quadro da evolução crustal estabelecido com base em datações U-Pb, Rb-Sr, Pb-Pb e Sm-Nd, é apresentada uma interpretação acerca da história tectonotermal do CSF, durante o Proterozóico. A análise da informação é realizada por região geográfica (setores central, NE, NW, SW, meridional e leste), e com base nos padrões de idade K-Ar em micas e anfibólios. As interpretações são comparadas com o quadro evolutivo, tanto das rochas da infraestrutura como da supraestrutura do CSF, e levando em conta também o padrão geocronológico K-Ar nas faixas móveis adjacentes. O registro de idades entre 2,1 e 1,8 Ga, na maior parte da infraestrutura indica o soerguimento gradativo do CSF que acompanhou a estabilização tectónica dos cinturões Itabuna, Correntina-Guanambi e Mineiro, durante o Ciclo Transamazônico. As idades entre 1,72 e 1,65 Ga, registradas na extremidade nordeste do cinturão Itabuna e no cinturão Mineiro, são interpretadas como um reflexo do soerguimento associado ao colapso extensional do rift Espinhaço, cuja origem se deu há 1,75 Ga. Os intervalos de idade 0,80/0,65 Ga e 0,65/0,50 Ga, detectados nas bordas do CSF e no interior da província Paramirim, são interpretados como relacionados aos processos colisionais das faixas móveis marginais neoproterozóicas. Em especial, esta província parece representar uma zona reativada (deformação, metamorfismo e rejuvenescimento isotópico), como reflexo da tectónica convergente das faixas Rio Preto e Araçuaí em relação ao CSF. A análise integrada da geocronologia K-Ar, aliada aos dados geológicos e estruturais, e ao cenário da evolução crustal, sugere que o CSF manteve-se como unidade fisicamente íntegra durante o Neoproterozóico, embora as rochas da infraestrutura nas margens leste e sudeste e na província Paramirim tenham sido fortemente reativadas durante o Brasiliano

Evaluation of a microarray for genotyping polymorphisms related to xenobiotic metabolism and DNA repair

We present an oligonucleotide microarray ("MetaboChip") based on the arrayed primer extension (APEX) technique, allowing genotyping of single nucleotide polymorphisms (SNPs) in genes of interest fo..

Haplotype of prostaglandin synthase 2/cyclooxygenase 2 is involved in the susceptibility to inflammatory bowel disease

AIM: Prostaglandin G/H synthase 2 (PTGS2 or COX2) is one of the key factors in the cellular response to inflammation. PTGS2 is expressed in the affected intestinal segments of patients with inflammatory bowel diseases (IBD). In IBD patients, non-steroidal anti-inflammatory drugs, which have been shown to reduce both the production and activity of PTGS2, may activate IBD and aggravate the symptoms. We aimed at examining genetic variants of PTGS2 that may be risk factors for IBD. METHODS: We genotyped 291 individuals diagnosed with IBD and 367 controls from the Dutch population for the five most frequent polymorphisms of the PTGS2 gene. Clinical data were collected on all patients. DNA was extracted via normal laboratory methods. Genotyping was carried out using multiplex PCR followed by the Invader Assay and the 5 exonuclease assay (TaqMan). New polymorphism screening was performed by pre-screening with denaturing high-performance liquid chromatography, followed by fluorescent sequencing. RESULTS: Allele 5209G was weakly associated with Crohn's disease (odds ratio [OR] 1.63, 95% confidence interval [CI] 1.03-2.57), and allele 8473T with ulcerative colitis (OR 1.50, 95%CI 1.00-2.27). The haplotype including both alleles showed a strong association with IBD (OR 13.15, 95%CI 3.17-116.15). This haplotype, while rare (-0.3%) in the general population, is found more frequently in patients (3.5%). CONCLUSION: Our data suggest that this haplotype of PTGS2 contributes to the susceptibility of IBD

Bitter taste receptor polymorphisms and human aging.

Several studies have shown that genetic factors account for 25% of the variation in human life span. On the basis of published molecular, genetic and epidemiological data, we hypothesized that genetic polymorphisms of taste receptors, which modulate food preferences but are also expressed in a number of organs and regulate food absorption processing and metabolism, could modulate the aging process. Using a tagging approach, we investigated the possible associations between longevity and the common genetic variation at the three bitter taste receptor gene clusters on chromosomes 5, 7 and 12 in a population of 941 individuals ranging in age from 20 to 106 years from the South of Italy. We found that one polymorphism, rs978739, situated 212 bp upstream of the TAS2R16 gene, shows a statistically significant association (p = 0.001) with longevity. In particular, the frequency of A/A homozygotes increases gradually from 35% in subjects aged 20 to 70 up to 55% in centenarians. These data provide suggestive evidence on the possible correlation between human longevity and taste genetics

POMC and TP53 genetic variability and risk of basal cell carcinoma of skin: Interaction between host and genetic factors.

Background: Basal cell carcinoma (BCC) of the skin is the most common neoplasm among the Caucasian population of the western world. Ultraviolet (UV) radiation-induced p53 activation promotes cutaneous pigmentation by increasing transcriptional activity of pro-opiomelanocortin (POMC) in the skin. Induction of POMC/-melanocyte-stimulating hormone (α-MSH) activates the melanocortin 1 receptor (MC1R), resulting in skin pigmentation. The tumor suppressor p53 is a key player in stress responses that preserve genomic stability, responding to a variety of insults including DNA damage, hypoxia, metabolic stress and oncogene activation. Malfunction of the p53 pathway is an almost universal hallmark of human tumors. Polymorphisms in the gene encoding p53 (TP53) alter its transcriptional activity, which in turn may influence the UV radiation-induced tanning response. Objective: The aim of the present work is to test association between POMC and TP53 genetic variability, the possible interplay with host factors and the risk of basal cell carcinoma of skin. Methods: We covered the variability of the two genes we used 17 tagging polymorphisms in 529 BCC cases and 532 healthy controls. We have also tested the possible interactions between the genetic variants and three known risk factors for BCC: skin complexion, sun effect and skin response to sun exposure. Results: We did not observe any statistically significant association between SNPs in these two genes and BCC risk overall, nor interactions of SNPs with known BCC risk factors. However we found that, in the group of subjects with lower sun exposure, carriers of one copy of the C allele of the TP53 SNP rs12951053 had a decreased risk of BCC (OR = 0.28, 95% CI 0.12-0.62, P= 0.002). Conclusions: We have observed that the interplay of an environmental risk factor and one polymorphism in TP53 gene could modulate the risk of BCC

Preliminary Parallaxes of 40 L and T Dwarfs from the U.S. Naval Observatory Infrared Astrometry Program

We present preliminary trigonometric parallaxes and proper motions for 22 L dwarfs and 18 T dwarfs measured using the ASTROCAM infrared imager. Relative to absolute parallax corrections are made by employing 2MASS and/or SDSS photometry for reference frame stars. We combine USNO infrared and optical parallaxes with the best available CIT system photometry to determine M_J, M_H, and M_K values for 37 L dwarfs between spectral types L0 to L8 and 19 T dwarfs between spectral types T0.5 and T8 and present selected absolute magnitude versus spectral type and color diagrams, based on these results. Luminosities and temperatures are estimated for these objects. Of special interest are the distances of several objects which are at or near the L-T dwarf boundary so that this important transition can be better understood. The previously reported early-mid T dwarf luminosity excess is clearly confirmed and found to be present at J, H, and K. The large number of objects that populate this luminosity excess region indicates that it cannot be due entirely to selection effects. The T dwarf sequence is extended to M_J~16.9 by 2MASS J041519-0935 which, at d = 5.74 pc, is found to be the least luminous [log(L/L_sun)=-5.58] and coldest (T_eff~760 K) brown dwarf known. Combining results from this paper with earlier USNO CCD results we find that, in contrast to the L dwarfs, there are no examples of low velocity (V_tan < 20 km/s) T dwarfs. We briefly discuss future directions for the USNO infrared astrometry program.Comment: 73 pages, 9 figures, 9 tables, accepted for publication in The Astronomical Journa