| 1. |
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| 2. |
- Pantazis, N, et al.
(författare)
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Determining the likely place of HIV acquisition for migrants in Europe combining subject-specific information and biomarkers data
- 2019
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Ingår i: Statistical methods in medical research. - : SAGE Publications. - 1477-0334 .- 0962-2802. ; 28:7, s. 1979-1997
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Tidskriftsartikel (refereegranskat)abstract
- In most HIV-positive individuals, infection time is only known to lie between the time an individual started being at risk for HIV and diagnosis time. However, a more accurate estimate of infection time is very important in certain cases. For example, one of the objectives of the Advancing Migrant Access to Health Services in Europe (aMASE) study was to determine if HIV-positive migrants, diagnosed in Europe, were infected pre- or post-migration. We propose a method to derive subject-specific estimates of unknown infection times using information from HIV biomarkers’ measurements, demographic, clinical, and behavioral data. We assume that CD4 cell count (CD4) and HIV-RNA viral load trends after HIV infection follow a bivariate linear mixed model. Using post-diagnosis CD4 and viral load measurements and applying the Bayes’ rule, we derived the posterior distribution of the HIV infection time, whereas the prior distribution was informed by AIDS status at diagnosis and behavioral data. Parameters of the CD4–viral load and time-to-AIDS models were estimated using data from a large study of individuals with known HIV infection times (CASCADE). Simulations showed substantial predictive ability (e.g. 84% of the infections were correctly classified as pre- or post-migration). Application to the aMASE study ( n = 2009) showed that 47% of African migrants and 67% to 72% of migrants from other regions were most likely infected post-migration. Applying a Bayesian method based on bivariate modeling of CD4 and viral load, and subject-specific information, we found that the majority of HIV-positive migrants in aMASE were most likely infected after their migration to Europe.
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| 3. |
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| 4. |
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| 5. |
- Borges, A. H., et al.
(författare)
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Nonnucleoside Reverse-transcriptase Inhibitor- vs Ritonavir-boosted Protease Inhibitor-based Regimens for Initial Treatment of HIV Infection: A Systematic Review and Metaanalysis of Randomized Trials
- 2016
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Ingår i: Clinical Infectious Diseases. - : Oxford University Press (OUP). - 1058-4838 .- 1537-6591. ; 63:2, s. 268-280
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Tidskriftsartikel (refereegranskat)abstract
- Background. Previous studies suggest that nonnucleoside reverse-transcriptase inhibitors (NNRTIs) cause faster virologic suppression, while ritonavir-boosted protease inhibitors (PI/r) recover more CD4 cells. However, individual trials have not been powered to compare clinical outcomes. Methods. We searched databases to identify randomized trials that compared NNRTI-vs PI/r-based initial therapy. A meta-analysis calculated risk ratios (RRs) or mean differences (MDs), as appropriate. Primary outcome was death or progression to AIDS. Secondary outcomes were death, progression to AIDS, and treatment discontinuation. We calculated RR of virologic suppression and MD for an increase in CD4 cells at week 48. Results. We included 29 trials with 9047 participants. Death or progression to AIDS occurred in 226 participants in the NNRTI arm and in 221 in the PI/r arm (RR, 1.03; 95% confidence interval, .87-1.22; 12 trials; n = 3825), death in 205 participants in the NNRTI arm vs 198 in the PI/r arm (1.04; 0.86-1.25; 22 trials; n = 8311), and progression to AIDS in 140 participants in the NNRTI arm vs 144 in the PI/r arm (1.00; 0.80-1.25; 13 trials; n = 4740). Overall treatment discontinuation (1.12; 0.93-1.35; 24 trials; n = 8249) and from toxicity (1.21; 0.87-1.68; 21 trials; n = 6195) were comparable, but discontinuation due to virologic failure was more common with NNRTI (1.58; 0.91-2.74; 17 trials; n = 5371). At week 48, there was no difference between NNRTI and PI/r in virologic suppression (RR, 1.03; 0.98-1.09) or CD4(+) recovery (MD, -4.7 cells; -14.2 to 4.8). Conclusions. We found no difference in clinical and viro-immunologic outcomes between NNRTI-and PI/r-based therapy.
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| 6. |
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| 7. |
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| 8. |
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| 9. |
- Caby, F, et al.
(författare)
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CD4/CD8 Ratio and the Risk of Kaposi Sarcoma or Non-Hodgkin Lymphoma in the Context of Efficiently Treated Human Immunodeficiency Virus (HIV) Infection: A Collaborative Analysis of 20 European Cohort Studies
- 2021
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Ingår i: Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. - : Oxford University Press (OUP). - 1537-6591. ; 73:1, s. 50-59
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundA persistently low CD4/CD8 ratio has been reported to inversely correlate with the risk of non-AIDS defining cancer in people living with human immunodeficiency virus (HIV; PLWH) efficiently treated by combination antiretroviral therapy (cART). We evaluated the impact of the CD4/CD8 ratio on the risk of Kaposi sarcoma (KS) or non-Hodgkin lymphoma (NHL), still among the most frequent cancers in treated PLWH.MethodsPLWH from the Collaboration of Observational HIV Epidemiological Research Europe (COHERE) were included if they achieved virological control (viral load ≤ 500 copies/mL) within 9 months following cART and without previous KS/LNH diagnosis. Cox models were used to identify factors associated with KS or NHL risk, in all participants and those with CD4 ≥ 500/mm3 at virological control. We analyzed the CD4/CD8 ratio, CD4 count and CD8 count as time-dependent variables, using spline transformations.ResultsWe included 56 708 PLWH, enrolled between 2000 and 2014. At virological control, the median (interquartile range [IQR]) CD4 count, CD8 count, and CD4/CD8 ratio were 414 (296–552)/mm3, 936 (670–1304)/mm3, and 0.43 (0.28–0.65), respectively. Overall, 221 KS and 187 NHL were diagnosed 9 (2–37) and 18 (7–42) months after virological control. Low CD4/CD8 ratios were associated with KS risk (hazard ratio [HR] = 2.02 [95% confidence interval {CI } = 1.23–3.31]) when comparing CD4/CD8 = 0.3 to CD4/CD8 = 1) but not with NHL risk. High CD8 counts were associated with higher NHL risk (HR = 3.14 [95% CI = 1.58–6.22]) when comparing CD8 = 3000/mm3 to CD8 = 1000/mm3). Similar results with increased associations were found in PLWH with CD4 ≥ 500/mm3 at virological control (HR = 3.27 [95% CI = 1.60–6.56] for KS; HR = 5.28 [95% CI = 2.17–12.83] for NHL).ConclusionsLow CD4/CD8 ratios and high CD8 counts despite effective cART were associated with increased KS/NHL risks respectively, especially when CD4 ≥ 500/mm3.
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| 10. |
- Tang, X. D., et al.
(författare)
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Kinetic temperature of massive star-forming molecular clumps measured with formaldehyde: IV. The ALMA view of N113 and N159W in the LMC
- 2021
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 655
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Tidskriftsartikel (refereegranskat)abstract
- We mapped the kinetic temperature structure of two massive star-forming regions, N113 and N159W, in the Large Magellanic Cloud (LMC). We have used 1.6 (0.4 pc) resolution measurements of the para-H2CO JKaKc = 303-202, 322-221, and 321-220 transitions near 218.5 GHz to constrain RADEX non local thermodynamic equilibrium models of the physical conditions. The gas kinetic temperatures derived from the para-H2CO line ratios 322-221/303-202 and 321-220/303-202 range from 28 to 105 K in N113 and 29 to 68 K in N159W. Distributions of the dense gas traced by para-H2CO agree with those of the 1.3 mm dust and Spitzer 8.0 μm emission, but they do not significantly correlate with the Hα emission. The high kinetic temperatures (Tkin50 K) of the dense gas traced by para-H2CO appear to be correlated with the embedded infrared sources inside the clouds and/or young stellar objects in the N113 and N159W regions. The lower temperatures (Tkin < 50 K) were measured at the outskirts of the H2CO-bearing distributions of both N113 and N159W. It seems that the kinetic temperatures of the dense gas traced by para-H2CO are weakly affected by the external sources of the Hα emission. The non thermal velocity dispersions of para-H2CO are well correlated with the gas kinetic temperatures in the N113 region, implying that the higher kinetic temperature traced by para-H2CO is related to turbulence on a 0.4 pc scale. The dense gas heating appears to be dominated by internal star formation activity, radiation, and/or turbulence. It seems that the mechanism heating the dense gas of the star-forming regions in the LMC is consistent with that in Galactic massive star-forming regions located in the Galactic plane.
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| 11. |
- Cormier, D., et al.
(författare)
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The molecular gas reservoir of 6 low-metallicity galaxies from the Herschel Dwarf Galaxy Survey A ground-based follow-up survey of CO(1-0), CO(2-1), and CO(3-2)
- 2014
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 564
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Tidskriftsartikel (refereegranskat)abstract
- Context. Observations of nearby starburst and spiral galaxies have revealed that molecular gas is the driver of star formation. However, some nearby low-metallicity dwarf galaxies are actively forming stars, but CO, the most common tracer of this reservoir, is faint, leaving us with a puzzle about how star formation proceeds in these environments. Aims. We aim to quantify the molecular gas reservoir in a subset of 6 galaxies from the Herschel Dwarf Galaxy Survey with newly acquired CO data and to link this reservoir to the observed star formation activity. Methods. We present CO(1-0), CO(2-1), and CO(3-2) observations obtained at the ATNE Mopra 22-m, APEX, and IRAM 30-m telescopes, as well as [CII] 157 mu m and [OI] 63 mu m observations obtained with the Herschel/PACS spectrometer in the 6 low-metallicity dwarf galaxies: Haro 11, Mrk 1089, Mrk 930, NGC 4861, NGC 625, and UM 311. We derived their molecular gas masses from several methods, including using the CO-to-H-2 conversion factor X-CO (both Galactic and metallicity-scaled values) and dust measurements. The molecular and atomic gas reservoirs were compared to the star formation activity. We also constrained the physical conditions of the molecular clouds using the non-LTE code RADEX and the spectral synthesis code Cloudy. Results. We detect CO in 5 of the 6 galaxies, including first detections in Haro 11 (Z similar to 0.4 Z(circle dot)), Mrk 930 (0.2 Z(circle dot)), and UM 311 (0.5 Z(circle dot)), but CO remains undetected in NGC 4861 (0.2 Z(circle dot)). The CO luminosities are low, while [CII] is bright in these galaxies, resulting in [CII]/CO(1-0) >= 10 000. Our dwarf galaxies are in relatively good agreement with the Schmidt-Kennicutt relation for total gas. They show short molecular depletion timescales, even when considering metallicity-scaled X-CO factors. Those galaxies are dominated by their HI gas, except Haro 11, which has high star formation efficiency and is dominated by ionized and molecular gas. We determine the mass of each ISM phase in Haro 11 using Cloudy and estimate an equivalent X-CO factor that is 10 times higher than the Galactic value. Overall, our results confirm the emerging picture that CO suffers from significant selective photodissociation in low-metallicity dwarf galaxies.
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| 12. |
- Henkel, C., et al.
(författare)
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Molecular line emission in NGC 4945, imaged with ALMA
- 2018
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 615
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Tidskriftsartikel (refereegranskat)abstract
- NGC 4945 is one of the nearest (D ≈ 3.8 Mpc; 1 00 ≈ 19 pc) starburst galaxies. To investigate the structure, dynamics, and composition of the dense nuclear gas of this galaxy, ALMA band 3 (λ ≈ 3−4 mm) observations were carried out with ≈2 00 resolution. Three HCN and two HC + isotopologues, CS, C 3 H 2 , SiO, HCO, and CH 3 C 2 H were measured. Spectral line imaging demonstrates the presence of a rotating nuclear disk of projected size 10 00 × 2 00 reaching out to a galactocentric radius of r ≈ 100 pc with position angle PA = 45 ◦ ± 2 ◦ , inclination i = 75 ◦ ± 2 ◦ and an unresolved bright central core of size <∼ 2 00 . The continuum source, representing mostly free-free radiation from star forming regions, is more compact than the nuclear disk by a linear factor of two but shows the same position angle and is centered 0 00 . 39 ± 0 00 . 14 northeast of the nuclear accretion disk defined by H 2 O maser emission. Near the systemic velocity but outside the nuclear disk, both HCN J = 1 → 0 and CS J = 2 → 1 delineate molecular arms of length >∼ 15 00 ( >∼ 285 pc) on opposite sides of the dynamical center. These are connected by a (deprojected) ≈ 0.6 kpc sized molecular bridge, likely a dense gaseous bar seen almost ends-on, shifting gas from the front and back side into the nuclear disk. Modeling this nuclear disk located farther inside (r <∼ 100 pc) with tilted rings provides a good fit by inferring a coplanar outflow reaching a characteristic deprojected velocity of ≈50 km s −1 . All our molecular lines, with the notable exception of CH 3 C 2 H, show significant absorption near the systemic velocity (≈571 km s −1 ), within the range ≈500-660 km s −1 . Apparently, only molecular transitions with low critical H 2 density (n crit<∼ 10 4 cm −3 ) do not show absorption. The velocity field of the nuclear disk, derived from CH 3 C 2 H, provides evidence for rigid rotation in the inner few arcseconds and a dynamical mass of M tot = (2.1 ± 0.2) × 10 8 M inside a galactocentric radius of 2 00 . 45 (≈45 pc), with a significantly flattened rotation curve farther out. Velocity integrated line intensity maps with most pronounced absorption show molecular peak positions up to ≈1 00 . 5 (≈30 pc) southwest of the continuum peak, presumably due to absorption, which appears to be most severe slightly northeast of the nuclear maser disk. A nitrogen isotope ratio of 14 N/ 15 N ≈ 200-450 is estimated. This range of values is much higher then previously reported on a tentative basis. Therefore, because 15 N is less abundant than expected, the question for strong 15 N enrichment by massive star ejecta in starbursts still remains to be settled.
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| 13. |
- Martin, S., et al.
(författare)
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ALCHEMI, an ALMA Comprehensive High-resolution Extragalactic Molecular Inventory: Survey presentation and first results from the ACA array
- 2021
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 656
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Tidskriftsartikel (refereegranskat)abstract
- Context. The interstellar medium is the locus of physical processes affecting the evolution of galaxies which drive or are the result of star formation activity, supermassive black hole growth, and feedback. The resulting physical conditions determine the observable chemical abundances that can be explored through molecular emission observations at millimeter and submillimeter wavelengths. Aims. Our goal is to unveiling the molecular richness of the central region of the prototypical nearby starburst galaxy NGC 253 at an unprecedented combination of sensitivity, spatial resolution, and frequency coverage. Methods. We used the Atacama Large Millimeter/submillimeter Array (ALMA), covering a nearly contiguous 289 GHz frequency range between 84.2 and 373.2 GHz, to image the continuum and spectral line emission at 1.6″(∼28 pc) resolution down to a sensitivity of 30 - 50 mK. This article describes the ALMA Comprehensive High-resolution Extragalactic Molecular Inventory (ALCHEMI) large program. We focus on the analysis of the spectra extracted from the 15″ (∼255 pc) resolution ALMA Compact Array data. Results. We modeled the molecular emission assuming local thermodynamic equilibrium with 78 species being detected. Additionally, multiple hydrogen and helium recombination lines are identified. Spectral lines contribute 5 to 36% of the total emission in frequency bins of 50 GHz. We report the first extragalactic detections of C2H5OH, HOCN, HC3HO, and several rare isotopologues. Isotopic ratios of carbon, oxygen, sulfur, nitrogen, and silicon were measured with multiple species. Concluison. Infrared pumped vibrationaly excited HCN, HNC, and HC3N emission, originating in massive star formation locations, is clearly detected at low resolution, while we do not detect it for HCO+. We suggest high temperature conditions in these regions driving a seemingly "carbon-rich"chemistry which may also explain the observed high abundance of organic species close to those in Galactic hot cores. The Lvib/LIR ratio was used as a proxy to estimate a 3% contribution from the proto super star cluster to the global infrared emission. Measured isotopic ratios with high dipole moment species agree with those within the central kiloparsec of the Galaxy, while those derived from 13C/18O are a factor of five larger, confirming the existence of multiple interstellar medium components within NGC 253 with different degrees of nucleosynthesis enrichment. The ALCHEMI data set provides a unique template for studies of star-forming galaxies in the early Universe.
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| 14. |
- Sakamoto, K., et al.
(författare)
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P Cygni Profiles of Molecular Lines Toward Arp 220 Nuclei
- 2009
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Ingår i: Astrophysical Journal Letters. - 2041-8213 .- 2041-8205. ; 700:2, s. L104-L108
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Tidskriftsartikel (refereegranskat)abstract
- We report ~100 pc (0farcs3) resolution observations of (sub)millimeter HCO+ and CO lines in the ultraluminous infrared galaxy Arp 220. The lines peak at two merger nuclei, with HCO+ being more spatially concentrated than CO. Asymmetric line profiles with blueshifted absorption and redshifted emission are discovered in HCO+(3-2) and (4-3) toward the two nuclei and in CO(3-2) toward one nucleus. We suggest that these P Cygni profiles are due to ~100 km s–1 outward motion of molecular gas from the nuclei. This gas is most likely outflowing from the inner regions of the two nuclear disks rotating around individual nuclei, clearing the shroud around the luminosity sources there.
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| 15. |
- Sakamoto, K., et al.
(författare)
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Resolved Structure of the Arp 220 Nuclei at lambda approximate to 3 mm
- 2017
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 849:1
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Tidskriftsartikel (refereegranskat)abstract
- We analyze the 3 mm emission of the ultraluminous infrared galaxy Arp 220 for the spatially resolved structure and the spectral properties of the merger nuclei. ALMA archival data at similar to 0.'' 05 resolution are used for extensive visibility fitting and deep imaging of the continuum emission. The data are fitted well by two concentric components for each nucleus, such as two Gaussians or one Gaussian plus one exponential disk. The larger components in the individual nuclei are similar in shape and extent, similar to 100-150 pc, to the centimeter wave emission due to supernovae. They are therefore identified with the known starburst nuclear disks. The smaller components in both nuclei have about a few 10 pc sizes and peak brightness temperatures (Tb) more than twice higher than those in previous single-Gaussian fitting. They correspond to the dust emission that we find centrally concentrated in both nuclei by subtracting the plasma emission measured at 33 GHz. The dust emission in the western nucleus is found to have a peak Tb approximate to 530 K and an FWHM of about 20 pc. This component is estimated to have a bolometric luminosity on the order of 1012.5L& and a 20 pc scale luminosity surface density 1015.5L& kpc-2. A luminous active galactic nucleus is a plausible energy source for these high values while other explanations remain to be explored. Our continuum image also reveals a third structural component of the western nucleus- a pair of faint spurs perpendicular to the disk major axis. We attribute it to a bipolar outflow from the highly inclined (i approximate to 60 degrees) western nuclear disk.
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| 16. |
- Sakamoto, K., et al.
(författare)
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Resolved Structure of the Arp 220 Nuclei at λ ≈ 3 mm
- 2017
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 849:1
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Tidskriftsartikel (refereegranskat)abstract
- We analyze the 3 mm emission of the ultraluminous infrared galaxy Arp 220 for the spatially resolved structure and the spectral properties of the merger nuclei. ALMA archival data at ∼0.″05 resolution are used for extensive visibility fitting and deep imaging of the continuum emission. The data are fitted well by two concentric components for each nucleus, such as two Gaussians or one Gaussian plus one exponential disk. The larger components in the individual nuclei are similar in shape and extent, ∼100-150 pc, to the centimeter wave emission due to supernovae. They are therefore identified with the known starburst nuclear disks. The smaller components in both nuclei have about a few 10 pc sizes and peak brightness temperatures (Tb) more than twice higher than those in previous single-Gaussian fitting. They correspond to the dust emission that we find centrally concentrated in both nuclei by subtracting the plasma emission measured at 33 GHz. The dust emission in the western nucleus is found to have a peak Tb ≈ 530 K and an FWHM of about 20 pc. This component is estimated to have a bolometric luminosity on the order of 1012.5,Lo˙ and a 20 pc scale luminosity surface density 1015.5, Lo˙ kpc-2. A luminous active galactic nucleus is a plausible energy source for these high values while other explanations remain to be explored. Our continuum image also reveals a third structural component of the western nucleus - a pair of faint spurs perpendicular to the disk major axis. We attribute it to a bipolar outflow from the highly inclined (i ≈ 60°) western nuclear disk.
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| 17. |
- Sakamoto, K., et al.
(författare)
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Submillimeter Interferometry of the Luminous Infrared Galaxy NGC 4418: A Hidden Hot Nucleus with an Inflow and an Outflow
- 2013
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 764:1, s. 42-66
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Tidskriftsartikel (refereegranskat)abstract
- We have observed the nucleus of the nearby luminous infrared galaxy NGC 4418 with subarcsec resolution at 860and 450 μmfor the first time to characterize its hidden power source. A∼20 pc (0″.1) hot dusty core was found inside a 100 pc scale concentration of molecular gas at the galactic center. The 860 μm continuum core has a deconvolved (peak) brightness temperature of 120–210 K. The CO(3–2) peak brightness temperature there is as high as 90 K at 50 pc resolution. The core has a bolometric luminosity of about 1011 L☉ which accounts for most of the galaxy luminosity. It is Compton thick (NH≳1025 cm−2) and has a high luminosity-to-mass ratio (L/M) ∼ 500 L☉ M☉−1 as well as a high luminosity surface density 108.5±0.5L☉ pc−2. These parameters are consistent with an activegalactic nucleus to be the main luminosity source (with an Eddington ratio about 0.3), while they can be also due to a young starburst near its maximum L/M. We also found an optical color (reddening) feature that we attribute to an outflow cone emanating from the nucleus. The hidden hot nucleus thus shows evidence of both an inflow, previously seen with absorption lines, and the new outflow reported here in a different direction. The nucleus must be rapidly evolving with these gas flows.
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| 18. |
- Vakis, A.I., et al.
(författare)
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Modeling and simulation in tribology across scales : An overview
- 2018
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Ingår i: Tribology International. - : Elsevier. - 0301-679X .- 1879-2464. ; 125, s. 169-199
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Tidskriftsartikel (refereegranskat)abstract
- This review summarizes recent advances in the area of tribology based on the outcome of a Lorentz Center workshop surveying various physical, chemical and mechanical phenomena across scales. Among the main themes discussed were those of rough surface representations, the breakdown of continuum theories at the nano- and micro-scales, as well as multiscale and multiphysics aspects for analytical and computational models relevant to applications spanning a variety of sectors, from automotive to biotribology and nanotechnology. Significant effort is still required to account for complementary nonlinear effects of plasticity, adhesion, friction, wear, lubrication and surface chemistry in tribological models. For each topic, we propose some research directions.
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| 19. |
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