| 51. |
- Falgarone, E., et al.
(författare)
-
CH+(1-0) and 13CH+(1-0) absorption lines in the direction of massive star-forming regions
- 2010
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 521:1
-
Tidskriftsartikel (refereegranskat)abstract
- We report the detection of the ground-state rotational transition of the methylidyne cation CH+ and its isotopologue (CH+)-C-13 toward the remote massive star-forming regions W33A, W49N, and W51 with the HIFI instrument onboard the Herschel satellite. Both lines are seen only in absorption against the dust continuum emission of the star-forming regions. The CH+ absorption is saturated over almost the entire velocity ranges sampled by the lines-of-sight that include gas associated with the star-forming regions (SFR) and Galactic foreground material. The CH+ column densities are inferred from the optically thin components. A lower limit of the isotopic ratio [(CH+)-C-12]/[(CH+)-C-13]> 35.5 is derived from the absorptions of foreground material toward W49N. The column density ratio, N(CH+)/N(HCO+), is found to vary by at least a factor 10, between 4 and > 40, in the Galactic foreground material. Line-of-sight 12CH+ average abundances relative to total hydrogen are estimated. Their average value, N(CH+)/NH > 2.6 x 10(-8), is higher than that observed in the solar neighborhood and confirms the high abundances of CH+ in the Galactic interstellar medium. We compare this result to the predictions of turbulent dissipation regions (TDR) models and find that these high abundances can be reproduced for the inner Galaxy conditions. It is remarkable that the range of predicted N(CH+)/ N(HCO+) ratios, from 1 to similar to 50, is comparable to that observed.
|
|
| 52. |
- Hartogh, P., et al.
(författare)
-
HIFI observations of water in the atmosphere of comet C/2008 Q3 (Garradd)
- 2010
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 518:Article Number: L150
-
Tidskriftsartikel (refereegranskat)abstract
- High-resolution far-infrared and sub-millimetre spectroscopy of water lines is an important tool to understand the physical and chemical properties of cometary atmospheres. We present observations of several rotational ortho- and para-water transitions in comet C/2008 Q3 (Garradd) performed with HIFI on Herschel. These observations have provided the first detection of the 2(12)-1(01) (1669 GHz) ortho and 1(11)-0(00) (1113 GHz) para transitions of water in a cometary spectrum. In addition, the ground-state transition 1(10)-1(01) at 557 GHz is detected and mapped. By detecting several water lines quasi-simultaneously and mapping their emission we can constrain the excitation parameters in the coma. Synthetic line profiles are computed using excitation models which include excitation by collisions, solar infrared radiation, and radiation trapping. We obtain the gas kinetic temperature, constrain the electron density profile, and estimate the coma expansion velocity by analyzing the map and line shapes. We derive water production rates of 1.7-2.8 x 10(28) s(-1) over the range r(h) = 1.83-1.85 AU.
|
|
| 53. |
- Gaudet, Mia M., et al.
(författare)
-
Common Genetic Variants and Modification of Penetrance of BRCA2-Associated Breast Cancer
- 2010
-
Ingår i: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7404. ; 6:10
-
Tidskriftsartikel (refereegranskat)abstract
- The considerable uncertainty regarding cancer risks associated with inherited mutations of BRCA2 is due to unknown factors. To investigate whether common genetic variants modify penetrance for BRCA2 mutation carriers, we undertook a two-staged genome-wide association study in BRCA2 mutation carriers. In stage 1 using the Affymetrix 6.0 platform, 592,163 filtered SNPs genotyped were available on 899 young (, 40 years) affected and 804 unaffected carriers of European ancestry. Associations were evaluated using a survival-based score test adjusted for familial correlations and stratified by country of the study and BRCA2*6174delT mutation status. The genomic inflation factor (lambda) was 1.011. The stage 1 association analysis revealed multiple variants associated with breast cancer risk: 3 SNPs had p-values, 10 25 and 39 SNPs had p-values<10(-4). These variants included several previously associated with sporadic breast cancer risk and two novel loci on chromosome 20 (rs311499) and chromosome 10 (rs16917302). The chromosome 10 locus was in ZNF365, which contains another variant that has recently been associated with breast cancer in an independent study of unselected cases. In stage 2, the top 85 loci from stage 1 were genotyped in 1,264 cases and 1,222 controls. Hazard ratios (HR) and 95% confidence intervals (CI) for stage 1 and 2 were combined and estimated using a retrospective likelihood approach, stratified by country of residence and the most common mutation, BRCA2*6174delT. The combined per allele HR of the minor allele for the novel loci rs16917302 was 0.75 (95% CI 0.66-0.86, p = 3: 8 x 10(-5)) and for rs311499 was 0.72 (95% CI 0.61-0.85, p = 6: 6 x 10(-5)). FGFR2 rs2981575 had the strongest association with breast cancer risk (per allele HR = 1.28, 95% CI 1.18-1.39, p = 1: 2 x 10(-8)). These results indicate that SNPs that modify BRCA2 penetrance identified by an agnostic approach thus far are limited to variants that also modify risk of sporadic BRCA2 wild-type breast cancer.
|
|
| 54. |
- Gerin, M., et al.
(författare)
-
Interstellar OH+, H2O+ and H3O+ along the sight-line to G10.6-0.4
- 2010
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 518:4, s. 110-
-
Tidskriftsartikel (refereegranskat)abstract
- We report the detection of absorption lines by the reactive ions OH+, H2O+ and H3O+ along the line of sight to the submillimeter continuum source G10.6$-$0.4 (W31C). We used the Herschel HIFI instrument in dual beam switch mode to observe the ground state rotational transitions of OH+ at 971 GHz, H2O+ at 1115 and 607 GHz, and H3O+ at 984 GHz. The resultant spectra show deep absorption over a broad velocity range that originates in the interstellar matter along the line of sight to G10.6$-$0.4 as well as in the molecular gas directly associated with that source. The OH+ spectrum reaches saturation over most velocities corresponding to the foreground gas, while the opacity of the H2O+ lines remains lower than 1 in the same velocity range, and the H3O+ line shows only weak absorption. For LSR velocities between 7 and 50 kms$^{-1}$ we estimate total column densities of $N$(OH+) $> 2.5 \times 10^{14}$ cm$^{-2}$, $N$(H2O+) $\sim 6 \times 10^{13}$ cm$^{-2}$ and $N$(H3O+) $\sim 4.0 \times 10^{13}$ cm$^{-2}$. These detections confirm the role of O$^+$ and OH$^+$ in initiating the oxygen chemistry in diffuse molecular gas and strengthen our understanding of the gas phase production of water. The high ratio of the OH+ by the H2O+ column density implies that these species predominantly trace low-density gas with a small fraction of hydrogen in molecular form.
|
|
| 55. |
- Teyssier, D., et al.
(författare)
-
Herschel/HIFI In-flight commissioning and performance
- 2010
-
Ingår i: 21st International Symposium on Space Terahertz Technology 2010, ISSTT 2010; Oxford; United Kingdom; 23 March 2010 through 25 March 2010. - 9781617823626 ; , s. 23-28
-
Konferensbidrag (refereegranskat)abstract
- The Herschel Space Observatory was successfully launched on the 14th of May, 2009, lifting into space the Heterodyne Instrument for the Far-Infrared (HIFI). After the standard early orbit operations on the Space-craft, the instrument was switched on for the first time on the 24th of May, kicking off an instrument Commissioning period of more than a month and a half. We present here the outcome of this Commissioning campaign, including the measured in-flight performance of the instrument. Among the challenges encountered during this period was the need to optimize the stability of the signal provided by the Local Oscillator (LO) chains in some of the frequency bands, in particular that covering the singly Ionized Carbon (C+) line at the upper edge of the HIFI range, and one of the backbones of the science program of the instrument. The same concept also allowed significant improvements in the upper end of the 3b LO chain. Another noticeable achievement was the very good co-alignment measured between the mixer beams in the respective H and V polarizations offered by HIFI, allowing for more than a simple build-in redundancy, as the observing efficiency will really benefits from the combination of the two mixers.
|
|
| 56. |
|
|
| 57. |
- de Boer, Wietse, et al.
(författare)
-
Mechanism of antibacterial activity of the white-rot fungus Hypholoma fasciculare colonizing wood
- 2010
-
Ingår i: Canadian journal of microbiology (Print). - : NRC Research Press. - 0008-4166 .- 1480-3275. ; 56:5, s. 380-388
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- In a previous study it was shown that the number of wood-inhabiting bacteria was drastically reduced after colonization of beech (Fagus sylvatica) wood blocks by the white-rot fungus Hypholoma fasciculare, or sulfur tuft (Folman et al. 2008). Here we report on the mechanisms of this fungal-induced antibacterial activity. Hypholoma fasciculare was allowed to invade beech and pine (Pinus sylvestris) wood blocks that had been precolonized by microorganisms from forest soil. The changes in the number of bacteria, fungal biomass, and fungal-related wood properties were followed for 23 weeks. Colonization by the fungus resulted in a rapid and large reduction in the number of bacteria (colony-forming units), which was already apparent after 4 weeks of incubation. The reduction in the number of bacteria coincided with fungal-induced acidification in both beech and pine wood blocks. No evidence was found for the involvement of toxic secondary metabolites or reactive oxygen species in the reduction of the number of bacteria. Additional experiments showed that the dominant bacteria present in the wood blocks were not able to grow under the acidic conditions (pH 3.5) created by the fungus. Hence our research pointed at rapid acidification as the major factor causing reduction of wood-inhabiting bacteria upon colonization of wood by H. fasciculare.
|
|
| 58. |
|
|
| 59. |
- Limdi, Nita A., et al.
(författare)
-
Warfarin pharmacogenetics : a single VKORC1 polymorphism is predictive of dose across three racial groups
- 2010
-
Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 115:18, s. 3827-3834
-
Tidskriftsartikel (refereegranskat)abstract
- Warfarin dosing algorithms incorporating CYP2C9 and VKORC1-1639G>A improve dose prediction compared to algorithms based solely on clinical and demographic factors. However these algorithms better capture dose variability among Whites compared to Asians or Blacks. Herein we evaluate whether other VKORC1 polymorphisms and haplotypes explain additional variation in warfarin dose beyond that explained by VKORC1-1639G>A among Asians (n=1103), Blacks (n=670) and Whites (n=3113). Participants were recruited from 11 countries as part of the International Warfarin Pharmacogenetics Consortium effort. Evaluation of the effects of individual VKORC1 SNPs and haplotypes on warfarin dose employed both univariate and multivariable linear regression. VKORC1-1639G>A and 1173C>T individually explained the greatest variance in dose in all three racial groups. Incorporation of additional VKORC1 SNPs or haplotypes did not further improve dose prediction. VKORC1 explained greater variability in dose among Whites as compared to Blacks and Asians. Differences in the percent variance in dose explained by VKORC1 across race was largely accounted for by the frequency of the -1639 A (or 1173 T) allele. Thus, clinicians should recognize that although at a population level, the contribution of VKORC1 towards dose requirements is higher in Whites compared to non-whites; genotype predicts similar dose requirements across racial groups.
|
|
| 60. |
|
|
