| 1. |
- Brown, A. G. A., et al.
(författare)
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Gaia Data Release 1 Summary of the astrometric, photometric, and survey properties
- 2016
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 595
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Tidskriftsartikel (refereegranskat)abstract
- Context. At about 1000 days after the launch of Gaia we present the first Gaia data release, Gaia DR1, consisting of astrometry and photometry for over 1 billion sources brighter than magnitude 20.7. Aims. A summary of Gaia DR1 is presented along with illustrations of the scientific quality of the data, followed by a discussion of the limitations due to the preliminary nature of this release. Methods. The raw data collected by Gaia during the first 14 months of the mission have been processed by the Gaia Data Processing and Analysis Consortium (DPAC) and turned into an astrometric and photometric catalogue. Results. Gaia DR1 consists of three components: a primary astrometric data set which contains the positions, parallaxes, and mean proper motions for about 2 million of the brightest stars in common with the HIPPARCOS and Tycho-2 catalogues - a realisation of the Tycho-Gaia Astrometric Solution (TGAS) - and a secondary astrometric data set containing the positions for an additional 1.1 billion sources. The second component is the photometric data set, consisting of mean G-band magnitudes for all sources. The G-band light curves and the characteristics of similar to 3000 Cepheid and RR Lyrae stars, observed at high cadence around the south ecliptic pole, form the third component. For the primary astrometric data set the typical uncertainty is about 0.3 mas for the positions and parallaxes, and about 1 mas yr(-1) for the proper motions. A systematic component of similar to 0.3 mas should be added to the parallax uncertainties. For the subset of similar to 94 000 HIPPARCOS stars in the primary data set, the proper motions are much more precise at about 0.06 mas yr(-1). For the secondary astrometric data set, the typical uncertainty of the positions is similar to 10 mas. The median uncertainties on the mean G-band magnitudes range from the mmag level to similar to 0.03 mag over the magnitude range 5 to 20.7. Conclusions. Gaia DR1 is an important milestone ahead of the next Gaia data release, which will feature five-parameter astrometry for all sources. Extensive validation shows that Gaia DR1 represents a major advance in the mapping of the heavens and the availability of basic stellar data that underpin observational astrophysics. Nevertheless, the very preliminary nature of this first Gaia data release does lead to a number of important limitations to the data quality which should be carefully considered before drawing conclusions from the data.
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| 2. |
- Prusti, T., et al.
(författare)
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The Gaia mission
- 2016
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 595
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Tidskriftsartikel (refereegranskat)abstract
- Gaia is a cornerstone mission in the science programme of the European Space Agency (ESA). The spacecraft construction was approved in 2006, following a study in which the original interferometric concept was changed to a direct-imaging approach. Both the spacecraft and the payload were built by European industry. The involvement of the scientific community focusses on data processing for which the international Gaia Data Processing and Analysis Consortium (DPAC) was selected in 2007. Gaia was launched on 19 December 2013 and arrived at its operating point, the second Lagrange point of the Sun-Earth-Moon system, a few weeks later. The commissioning of the spacecraft and payload was completed on 19 July 2014. The nominal five-year mission started with four weeks of special, ecliptic-pole scanning and subsequently transferred into full-sky scanning mode. We recall the scientific goals of Gaia and give a description of the as-built spacecraft that is currently (mid-2016) being operated to achieve these goals. We pay special attention to the payload module, the performance of which is closely related to the scientific performance of the mission. We provide a summary of the commissioning activities and findings, followed by a description of the routine operational mode. We summarise scientific performance estimates on the basis of in-orbit operations. Several intermediate Gaia data releases are planned and the data can be retrieved from the Gaia Archive, which is available through the Gaia home page.
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| 3. |
- van Leeuwen, F., et al.
(författare)
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Gaia Data Release 1 : Open cluster astrometry: Performance, limitations, and future prospects
- 2017
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 601
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Tidskriftsartikel (refereegranskat)abstract
- Context. The first Gaia Data Release contains the Tycho-Gaia Astrometric Solution (TGAS). This is a subset of about 2 million stars for which, besides the position and photometry, the proper motion and parallax are calculated using Hipparcos and Tycho-2 positions in 1991.25 as prior information. Aims. We investigate the scientific potential and limitations of the TGAS component by means of the astrometric data for open clusters. Methods. Mean cluster parallax and proper motion values are derived taking into account the error correlations within the astrometric solutions for individual stars, an estimate of the internal velocity dispersion in the cluster, and, where relevant, the effects of the depth of the cluster along the line of sight. Internal consistency of the TGAS data is assessed. Results. Values given for standard uncertainties are still inaccurate and may lead to unrealistic unit-weight standard deviations of least squares solutions for cluster parameters. Reconstructed mean cluster parallax and proper motion values are generally in very good agreement with earlier Hipparcos-based determination, although the Gaia mean parallax for the Pleiades is a significant exception. We have no current explanation for that discrepancy. Most clusters are observed to extend to nearly 15 pc from the cluster centre, and it will be up to future Gaia releases to establish whether those potential cluster-member stars are still dynamically bound to the clusters. Conclusions. The Gaia DR1 provides the means to examine open clusters far beyond their more easily visible cores, and can provide membership assessments based on proper motions and parallaxes. A combined HR diagram shows the same features as observed before using the Hipparcos data, with clearly increased luminosities for older A and F dwarfs.
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| 4. |
- Clementini, G., et al.
(författare)
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Testing parallaxes with local Cepheids and RR Lyrae stars
- 2017
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 605
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Tidskriftsartikel (refereegranskat)abstract
- Context. Parallaxes for 331 classical Cepheids, 31 Type II Cepheids, and 364 RR Lyrae stars in common between Gaia and the HIPPARCOS and Tycho-2 catalogues are published in Gaia Data Release 1 (DR1) as part of the Tycho-Gaia Astrometric Solution (TGAS). Aims. In order to test these first parallax measurements of the primary standard candles of the cosmological distance ladder, which involve astrometry collected by Gaia during the initial 14 months of science operation, we compared them with literature estimates and derived new period-luminosity (PL), period-Wesenheit (PW) relations for classical and Type II Cepheids and infrared PL, PL-metallicity (PLZ), and optical luminosity-metallicity (MV-[Fe/H]) relations for the RR Lyrae stars, with zero points based on TGAS.Methods. Classical Cepheids were carefully selected in order to discard known or suspected binary systems. The final sample comprises 102 fundamental mode pulsators with periods ranging from 1.68 to 51.66 days (of which 33 with sigma(omega)/omega < 0 : 5). The Type II Cepheids include a total of 26 W Virginis and BL Herculis stars spanning the period range from 1.16 to 30.00 days (of which only 7 with sigma(omega)/omega 0 : 5). The RR Lyrae stars include 200 sources with pulsation period ranging from 0.27 to 0.80 days (of which 112 with sigma(omega)/omega < 0 : 5). The new relations were computed using multi- band (V; I; J; K-s) photometry and spectroscopic metal abundances available in the literature, and by applying three alternative approaches: (i) linear least-squares fitting of the absolute magnitudes inferred from direct transformation of the TGAS parallaxes; (ii) adopting astrometry-based luminosities; and (iii) using a Bayesian fitting approach. The last two methods work in parallax space where parallaxes are used directly, thus maintaining symmetrical errors and allowing negative parallaxes to be used. The TGAS-based PL; PW; PLZ, and MV [Fe/H] relations are discussed by comparing the distance to the Large Magellanic Cloud provided by different types of pulsating stars and alternative fitting methods.Results. Good agreement is found from direct comparison of the parallaxes of RR Lyrae stars for which both TGAS and HST measurements are available. Similarly, very good agreement is found between the TGAS values and the parallaxes inferred from the absolute magnitudes of Cepheids and RR Lyrae stars analysed with the Baade-Wesselink method. TGAS values also compare favourably with the parallaxes inferred by theoretical model fitting of the multi-band light curves for two of the three classical Cepheids and one RR Lyrae star, which were analysed with this technique in our samples. The K-band PL relations show the significant improvement of the TGAS parallaxes for Cepheids and RR Lyrae stars with respect to the HIPPARCOS measurements. This is particularly true for the RR Lyrae stars for which improvement in quality and statistics is impressive.Conclusions. TGAS parallaxes bring a significant added value to the previous HIPPARCOS estimates. The relations presented in this paper represent the first Gaia-calibrated relations and form a work-in-progress milestone report in the wait for Gaia-only parallaxes of which a first solution will become available with Gaia Data Release 2 (DR2) in 2018.
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| 14. |
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| 15. |
- Busca, A, et al.
(författare)
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Outcome of COVID-19 in allogeneic stem cell transplant recipients: Results from the EPICOVIDEHA registry
- 2023
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Ingår i: Frontiers in immunology. - : Frontiers Media SA. - 1664-3224. ; 14, s. 1125030-
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Tidskriftsartikel (refereegranskat)abstract
- The outcome of COVID-19 in allogeneic hematopoietic stem cell transplantation (HSCT) recipients is almost uniformely considered poor. The aim of present study was to retrospectively analyse the outcome and risk factors for mortality in a large series of patients who developed COVID-19 infection after an allogeneic HSCT.MethodsThis multicenter retrospective study promoted by the European Hematology Association – Infections in Hematology Study Working Group, included 326 adult HSCT patients who had COVID-19 between January 2020 and March 2022.ResultsThe median time from HSCT to the diagnosis of COVID-19 was 268 days (IQR 86-713; range 0-185 days). COVID-19 severity was mild in 21% of the patients, severe in 39% and critical in 16% of the patients. In multivariable analysis factors associated with a higher risk of mortality were, age above 50 years, presence of 3 or more comorbidities, active hematologic disease at time of COVID-19 infection, development of COVID-19 within 12 months of HSCT, and severe/critical infections. Overall mortality rate was 21% (n=68): COVID-19 was the main or secondary cause of death in 16% of the patients (n=53).ConclusionsMortality in HSCT recipients who develop COVID-19 is high and largely dependent on age, comorbidities, active hematologic disease, timing from transplant and severity of the infection.
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| 16. |
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| 17. |
- Smiljanic, R., et al.
(författare)
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The Gaia-ESO Survey: The analysis of high-resolution UVES spectra of FGK-type stars
- 2014
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Ingår i: Astronomy & Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 570
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Tidskriftsartikel (refereegranskat)abstract
- Context. The ongoing Gaia-ESO Public Spectroscopic Survey is using FLAMES at the VLT to obtain high-quality medium-resolution Giraffe spectra for about 10(5) stars and high-resolution UVES spectra for about 5000 stars. With UVES, the Survey has already observed 1447 FGK-type stars. Aims. These UVES spectra are analyzed in parallel by several state-of-the-art methodologies. Our aim is to present how these analyses were implemented, to discuss their results, and to describe how a final recommended parameter scale is defined. We also discuss the precision (method-to-method dispersion) and accuracy (biases with respect to the reference values) of the final parameters. These results are part of the Gaia-ESO second internal release and will be part of its first public release of advanced data products. Methods. The final parameter scale is tied to the scale defined by the Gaia benchmark stars, a set of stars with fundamental atmospheric parameters. In addition, a set of open and globular clusters is used to evaluate the physical soundness of the results. Each of the implemented methodologies is judged against the benchmark stars to define weights in three different regions of the parameter space. The final recommended results are the weighted medians of those from the individual methods. Results. The recommended results successfully reproduce the atmospheric parameters of the benchmark stars and the expected T-eff-log g relation of the calibrating clusters. Atmospheric parameters and abundances have been determined for 1301 FGK-type stars observed with UVES. The median of the method-to-method dispersion of the atmospheric parameters is 55K for T-eff, 0.13dex for log g and 0.07 dex for [Fe/H]. Systematic biases are estimated to be between 50-100 K for T-eff, 0.10-0.25 dex for log g and 0.05-0.10 dex for [Fe/H]. Abundances for 24 elements were derived: C, N, O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Mo, Ba, Nd, and Eu. The typical method-to-method dispersion of the abundances varies between 0.10 and 0.20 dex. Conclusions. The Gaia-ESO sample of high-resolution spectra of FGK-type stars will be among the largest of its kind analyzed in a homogeneous way. The extensive list of elemental abundances derived in these stars will enable significant advances in the areas of stellar evolution and Milky Way formation and evolution.
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| 18. |
- Tunik, S P, et al.
(författare)
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Reactions of [H2OS3(CO)(10)] with conjugated diynes (RC2C2R ') containing nucleophilic oxygen in beta position of a substituent (R = Ph, R ' = CH2OH, C(O)Ph; R = R ' = CMe2(OH))
- 2003
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Ingår i: Organometallics. - : American Chemical Society (ACS). - 1520-6041 .- 0276-7333. ; 22:17, s. 3455-3465
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Tidskriftsartikel (refereegranskat)abstract
- Reactions of [H2Os3(CO)10] with a series of diynes, RC2C2R' (1: R = Ph, R' = CH2OH; 2: R = Ph, R' = C(O)Ph; 3: R = R' = C(OH)Me2), have been studied. It was found that upon coordination to the triosmium cluster, the nucleophilic oxygens of the R' substituents of 1 and 2 take part in intramolecular cyclization reactions to give [HOs3(CO)10{-1:2-PhCH2(C=CH-C=CH-O)}] (5) and [HOs3(CO)10{-1:1-Ph(C=CH-C=C-O)CPh}] (6), respectively, both of which contain furan rings coordinated to the cluster core. On heating of the latter compound, the furan moiety remains intact, but a carbonyl group dissociates from the cluster, leading to the formation of [HOs3(CO)9(3-1:3:1-Ph(C=CH-C=C-O)CPh)] (7) with a closed "C3Os3" pentagonal pyramidal structure. Reaction of [H2Os3(CO)10] with 3 does not lead to cyclization of the diyne; instead, the clusters [Os3(CO)10{3-2-(RCH=CH-C2R)}] (8) and [Os3(CO)10{3-2-(RC2C2R)}] (9) are formed. Deuterium labeling of the starting compounds has been used in the reaction of [H2Os3(CO)10] with HOCH2C2C2CH2OH in order to investigate possible mechanisms of the cyclization reaction. The crystal and molecular structures of clusters 5, 7, and 9 are presented.
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| 19. |
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| 20. |
- Amarsi, Anish, et al.
(författare)
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The GALAH Survey : non-LTE departure coefficients for large spectroscopic surveys
- 2020
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 642
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Tidskriftsartikel (refereegranskat)abstract
- Massive sets of stellar spectroscopic observations are rapidly becoming available and these can be used to determine the chemical composition and evolution of the Galaxy with unprecedented precision. One of the major challenges in this endeavour involves constructing realistic models of stellar spectra with which to reliably determine stellar abundances. At present, large stellar surveys commonly use simplified models that assume that the stellar atmospheres are approximately in local thermodynamic equilibrium (LTE). To test and ultimately relax this assumption, we have performed non-LTE calculations for 13 different elements (H, Li, C, N, O, Na, Mg, Al, Si, K, Ca, Mn, and Ba), using recent model atoms that have physically-motivated descriptions for the inelastic collisions with neutral hydrogen, across a grid of 3756 1D MARCS model atmospheres that spans 3000 <= T-eff/K <= 8000, - 0.5 <= log g/cm s(-2) <= 5.5, and - 5 <= [Fe/H] <= 1. We present the grids of departure coefficients that have been implemented into the GALAH DR3 analysis pipeline in order to complement the extant non-LTE grid for iron. We also present a detailed line-by-line re-analysis of 50 126 stars from GALAH DR3. We found that relaxing LTE can change the abundances by between - 0.7 dex and + 0.2 dex for different lines and stars. Taking departures from LTE into account can reduce the dispersion in the [A/Fe] versus [Fe/H] plane by up to 0.1 dex, and it can remove spurious differences between the dwarfs and giants by up to 0.2 dex. The resulting abundance slopes can thus be qualitatively different in non-LTE, possibly with important implications for the chemical evolution of our Galaxy. The grids of departure coefficients are publicly available and can be implemented into LTE pipelines to make the most of observational data sets from large spectroscopic surveys.
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| 21. |
- Begum, N, et al.
(författare)
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Dithiolate complexes of manganese and rhenium: X-ray structure and properties of an unusual mixed valence cluster Mn-3(CO)(6)(mu-eta(2)-SCH2CH2CH2S)(3)
- 2005
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 1520-510X .- 0020-1669. ; 44:26, s. 9887-9894
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Tidskriftsartikel (refereegranskat)abstract
- Treatment of Mn-2(CO)(10) with 3,4-toluenedithiol and 1,2-ethanedithiol in the presence of Me(3)NO(.)2H(2)O in CH2CI2 at room temperature afforded the dinuclear complexes Mn-2(CO)(6)(mu-eta(4)-SC6H3(CH3)S-SC6H3(CH3)S) (1), and Mn-2(CO)(6)(mu-eta(4)-SCH2CH2S-SCH2CH2S) (2), respectively. Similar reactions of Re-2(CO)(10) with 3,4-toluenedithiol, 1,2benzenedithiol, and 1,2-ethanedithiol yielded the dirhenium complexes Re-2(CO)(6)(mu-eta(4)-SC6H3(CH3)S-SC6H3(CH3)S) (3), Re-2(CO)(6)(mu-eta(4)-SCH2SC6H4S) (4), and Re-2(CO)(6)(SCH2CH2S-SCH2CH2S) (5), respectively. In contrast, treatment of Mn2(CO)10 with 1,3-propanedithiol afforded the trimanganese compound Mn-3(CO)(6)(mu-eta(2)-SCH2CH2CH2S)(3) (6), whereas Re2(CO)10 gave only intractable materials. The molecular structures of 1, 3, and 6 have been determined by single-crystal X-ray diffraction studies. The dimanganese and dirhenium carbonyl compounds 1-5 contain a binucleating disulfide ligand, formed by interligand disulfide bond formation between two dithiolate ligands identical in structure to that of the previously reported dimanganese complex Mn-2(CO)(6)(mu-eta(4)-SC6H4S-SC6H4S). Complex 6, on the other hand, forms a unique example of a mixed-valence trimangenese carbonyl compound containing three bridging 1,3-propanedithiolate ligands. The solution properties of 6 have been investigated by UV-vis and EPR spectroscopies as well as electrochemical techniques.
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| 22. |
- Bergemann, M., et al.
(författare)
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The Gaia-ESO Survey : radial metallicity gradients and age-metallicity relation of stars in the Milky Way disk
- 2014
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 565, s. A89-
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Tidskriftsartikel (refereegranskat)abstract
- We study the relationship between age, metallicity, and alpha-enhancement of FGK stars in the Galactic disk. The results are based upon the analysis of high-resolution UVES spectra from the Gaia-ESO large stellar survey. We explore the limitations of the observed dataset, i.e. the accuracy of stellar parameters and the selection effects that are caused by the photometric target preselection. We find that the colour and magnitude cuts in the survey suppress old metal-rich stars and young metal-poor stars. This suppression may be as high as 97% in some regions of the age-metallicity relationship. The dataset consists of 144 stars with a wide range of ages from 0.5 Gyr to 13.5 Gyr, Galactocentric distances from 6 kpc to 9.5 kpc, and vertical distances from the plane 0 < vertical bar Z vertical bar < 1.5 kpc. On this basis, we find that i) the observed age-metallicity relation is nearly flat in the range of ages between 0 Gyr and 8 Gyr; ii) at ages older than 9 Gyr, we see a decrease in [Fe/H] and a clear absence of metal-rich stars; this cannot be explained by the survey selection functions; iii) there is a significant scatter of [Fe/H] at any age; and iv) [Mg/Fe] increases with age, but the dispersion of [Mg/Fe] at ages > 9 Gyr is not as small as advocated by some other studies. In agreement with earlier work, we find that radial abundance gradients change as a function of vertical distance from the plane. The [Mg/Fe] gradient steepens and becomes negative. In addition, we show that the inner disk is not only more alpha-rich compared to the outer disk, but also older, as traced independently by the ages and Mg abundances of stars.
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| 23. |
- Bergman, Peter, et al.
(författare)
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Safety and efficacy of the mRNA BNT162b2 vaccine against SARS-CoV-2 in five groups of immunocompromised patients and healthy controls in a prospective open-label clinical trial
- 2021
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Ingår i: EBioMedicine. - : Elsevier BV. - 2352-3964. ; 74
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Tidskriftsartikel (refereegranskat)abstract
- Background: Patients with immunocompromised disorders have mainly been excluded from clinical trials of vaccination against COVID-19. Thus, the aim of this prospective clinical trial was to investigate safety and efficacy of BNT162b2 mRNA vaccination in five selected groups of immunocompromised patients and healthy controls.Methods: 539 study subjects (449 patients and 90 controls) were included. The patients had either primary (n=90), or secondary immunodeficiency disorders due to human immunodeficiency virus infection (n=90), allogeneic hematopoietic stem cell transplantation/CAR T cell therapy (n=90), solid organ transplantation (SOT) (n=89), or chronic lymphocytic leukemia (CLL) (n=90). The primary endpoint was seroconversion rate two weeks after the second dose. The secondary endpoints were safety and documented SARS-CoV-2 infection.Findings: Adverse events were generally mild, but one case of fatal suspected unexpected serious adverse reaction occurred. 72.2% of the immunocompromised patients seroconverted compared to 100% of the controls (p=0.004). Lowest seroconversion rates were found in the SOT (43.4%) and CLL (63.3%) patient groups with observed negative impact of treatment with mycophenolate mofetil and ibrutinib, respectively.Interpretation: The results showed that the mRNA BNT162b2 vaccine was safe in immunocompromised patients. Rate of seroconversion was substantially lower than in healthy controls, with a wide range of rates and antibody titres among predefined patient groups and subgroups. This clinical trial highlights the need for additional vaccine doses in certain immunocompromised patient groups to improve immunity.
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| 25. |
- Cattaneo, C, et al.
(författare)
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Simultaneous Onset of Haematological Malignancy and COVID: An Epicovideha Survey
- 2022
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Ingår i: Cancers. - : MDPI AG. - 2072-6694. ; 14:22
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Tidskriftsartikel (refereegranskat)abstract
- Background: The outcome of patients with simultaneous diagnosis of haematological malignancies (HM) and COVID-19 is unknown and there are no specific treatment guidelines. Methods: We describe the clinical features and outcome of a cohort of 450 patients with simultaneous diagnosis of HM and COVID-19 registered in the EPICOVIDEHA registry between March 2020 to February 2022. Results: Acute leukaemia and lymphoma were the most frequent HM (35.8% and 35.1%, respectively). Overall, 343 (76.2%) patients received treatment for HM, which was delayed for longer than one month since diagnosis in 57 (16.6%). An overall response rate was observed in 140 (40.8%) patients after the first line of treatment. After a median follow-up of 35 days, overall mortality was 177/450 (39.3%); 30-day mortality was significantly higher in patients not receiving HM treatment (42.1%) than in those receiving treatment (27.4%, p = 0.004), either before and/or after COVID-19, or compared to patients receiving HM treatment at least after COVID-19 (15.2%, p < 0.001). Age, severe/critical COVID-19, ≥2 comorbidities, and lack of HM treatment were independent risk factors for mortality, whereas a lymphocyte count >500/mcl at COVID-19 onset was protective. Conclusions: HM treatment should be delivered as soon as possible for patients with simultaneous diagnosis of COVID-19 and HM requiring immediate therapy.
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| 26. |
- Czaun, Miklos, et al.
(författare)
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An investigation of Cu(II) and Ni(II)-catalysed hydrolysis of (di)imines
- 2010
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Ingår i: Inorganica Chimica Acta. - : Elsevier BV. - 0020-1693. ; 363:12, s. 3102-3112
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Tidskriftsartikel (refereegranskat)abstract
- The reactions of six diimine ligands with Cu(II) and Ni(II) halide salts have been investigated. The diimine ligands were Ph2C=N(CH2)(n)NC=Ph-2 (n = 2 (Bz(2)en, 1a), 3 (Bz(2)pn, 1b), 4 (Bz2bn, 1c)), N, N'-bis-(2-tert-butylthio- 1-ylmethylenebenzene)-2,2'diamino-biphenyl (2), N,N'-bis-(2-chloro-1-ylmethylenebenzene)-1,3diaminobenzene (3) and N,N'-bis-(2-chloro-1-ylmethylenebenzene)-1,2-ethanediamine (4). Reactions of 1a-c, 2-4 with CuCl2 center dot 2H(2)O in dry ethanol at ambient temperature led to complete or partial hydrolysis of the diimine ligands to ultimately form copper diamine complexes. The non-hydrolyzed complexes of 1b and 1c, [Cu(L)Cl-2] (L = 1b, 1c), could be isolated when the reactions were carried out at low temperatures, and the half-hydrolyzed complex [Cu(Bzpn)Cl-2] could also be identified via X-ray crystallography. Similarly, reactions of 1a or 1b with NiCl2 center dot 6H(2)O or [NiBr2(dme)] led to rapid hydrolysis of the imines and Ni complexes containing half-hydrolyzed 1a (Bzen; [trans-[Ni(Bzen)(2)Br-2]) and 1b (Bzpn; [Ni(Bzpn) Br-2] could be isolated and identified via single crystal X-ray analysis. Kinetic studies were made of the hydrolyses of 1a, 1b in THF and 2 in acetone, in the presence of Cu(II), and of 1a in acetonitrile, in the presence of Ni(II). Activation parameters were determined for the latter reaction and for the copper-catalyzed hydrolysis of 2; the relatively large negative activation entropies clearly indicate rate-determining steps of an associative nature.
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| 27. |
- Edholm, Olle, et al.
(författare)
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The effect of water on the Fe3+/Fe2+ reduction potential of heme
- 2000
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Ingår i: Biochemical and Biophysical Research Communications - BBRC. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 268:3, s. 683-687
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Tidskriftsartikel (refereegranskat)abstract
- Hemeproteins can act as catalysts, oxygen carriers or electron conductors. The ferric/ferrous reduction potential E-m7 of iron in the center of the prosthetic group ranges from negative values for peroxidases to an extreme positive value for cytochrome a, with Hb and Mb in the middle [1]. Proteins exercise their influence on E-m7 in several ways: via substituents at the periphery of the chelate structure, via the proximal ligand, and via interaction with the surrounding medium, amino acid side chains, or polar solvents. Work on recombined proteins and ap-substituted free hemes documented that the first two effects are additive [2]. For the third effect, models of the dielectric media on a molecular level have been successfully applied [3-5]. E-m7 has also been empirically correlated to the degree of heme exposure to water [6-8]. The apoprotein/porphyrin and water/porphyrin interfaces are complementary since water molecules fill any empty space in the crevice and surround any pertinent part of heme outside the protein boundary. The present work links to this idea by a combination of statistical mechanics simulations and quantum mechanical calculations comparing heme in water with heme in an apolar environment. Our results show that polarization of the porphyrin pi-electron cloud by the held from water dipoles influences E-m7 The dominant effect of this and other determinates of iron electron availability is perturbations of delocalized electron density in the porphyrin chelate, reproduced by a model where the prosthetic group is treated as a disc of uniform electron density. The present work is also of interest since the interfacial energy constitutes the main barrier for heme-protein Separation [9-11].
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| 31. |
- Grachova, E V, et al.
(författare)
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The structure and dynamic behaviour of disubstituted derivatives of Rh6(CO)16 containing heterobidentate bridging phosphine ligands
- 2003
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Ingår i: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9234 .- 1477-9226. ; :12, s. 2468-2473
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Tidskriftsartikel (refereegranskat)abstract
- The solution structures and dynamic behaviour of [Rh6(CO)14(µ-PX)][PX = diphenyl(2-pyridyl)phosphine, (PN); diphenyl(2-thienyl)phosphine, (PS); diphenyl(vinyl)phosphine, (PV)] have been studied by multinuclear NMR and the X-ray structure of [Rh6(CO)14(µ,3-PV)] is reported. In solution, the above clusters undergo a variety of localised CO-exchanges and the mechanisms of these are discussed. The PV ligand in [Rh6(CO)14(µ,3-PV)] is hemilabile and exhibits facile exchange/reorientation of the vinyl group.
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| 32. |
- Jofré, P., et al.
(författare)
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Gaia FGK benchmark stars : abundances of α and iron-peak elements
- 2015
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 582
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Tidskriftsartikel (refereegranskat)abstract
- Context. In the current era of large spectroscopic surveys of the Milky Way, reference stars for calibrating astrophysical parameters and chemical abundances are of paramount importance. Aims. We determine elemental abundances of Mg, Si, Ca, Sc, Ti, V, Cr, Mn, Co, and Ni for our predefined set of Gaia FGK benchmark stars. Methods. By analysing high-resolution spectra with a high signal-to-noise ratio taken from several archive datasets, we combined results of eight different methods to determine abundances on a line-by-line basis. We performed a detailed homogeneous analysis of the systematic uncertainties, such as differential versus absolute abundance analysis. We also assessed errors that are due to non-local thermal equilibrium and the stellar parameters in our final abundances. Results. Our results are provided by listing final abundances and the different sources of uncertainties, as well as line-by-line and method-by-method abundances. Conclusions. The atmospheric parameters of the Gaia FGK benchmark stars are already being widely used for calibration of several pipelines that are applied to different surveys. With the added reference abundances of ten elements, this set is very suitable for calibrating the chemical abundances obtained by these pipelines.
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| 33. |
- Karovicova, I., et al.
(författare)
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Accurate effective temperatures of the metal-poor benchmark stars HD140283, HD122563, and HD103095 from CHARA interferometry
- 2018
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Ingår i: Monthly notices of the Royal Astronomical Society. - : OXFORD UNIV PRESS. - 0035-8711 .- 1365-2966 .- 1745-3925 .- 1745-3933. ; 475:1, s. L81-L85
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Tidskriftsartikel (refereegranskat)abstract
- Large stellar surveys of the MilkyWay require validation with reference to a set of 'benchmark' stars whose fundamental properties are well determined. For metal-poor benchmark stars, disagreement between spectroscopic and interferometric effective temperatures has called the reliability of the temperature scale into question. We present new interferometric measurements of three metal-poor benchmark stars, HD140283, HD122563, and HD103095, from which we determine their effective temperatures. The angular sizes of all the stars were determined from observations with the PAVO beam combiner at visible wavelengths at the CHARA array, with additional observations of HD103095 made with the VEGA instrument, also at the CHARA array. Together with photometrically derived bolometric fluxes, the angular diameters give a direct measurement of the effective temperature. For HD140283, we find theta(LD) = 0.324 +/- 0.005 mas, T-eff = 5787 +/- 48 K; for HD122563,theta(LD) = 0.926 +/- 0.011 mas, T-eff = 4636 +/- 37 K; and for HD103095,theta(LD) = 0.595 +/- 0.007 mas, T-eff = 5140 +/- 49 K. Our temperatures for HD140283 and HD103095 are hotter than the previous interferometric measurements by 253 and 322 K, respectively. We find good agreement between our temperatures and recent spectroscopic and photometric estimates. We conclude some previous interferometric measurements have been affected by systematic uncertainties larger than their quoted errors.
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| 34. |
- Marchetti, M, et al.
(författare)
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Outcomes of SARS-CoV-2 infection in Ph-neg chronic myeloproliferative neoplasms: results from the EPICOVIDEHA registry
- 2023
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Ingår i: Therapeutic advances in hematology. - : SAGE Publications. - 2040-6207 .- 2040-6215. ; 14, s. 20406207231154706-
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Tidskriftsartikel (refereegranskat)abstract
- Patients with Philadelphia-negative chronic myeloproliferative neoplasms (MPN) typically incur high rates of infections and both drugs and comorbidities may modulate infection risk. Objectives: The present study aims to assess the effect of immunosuppressive agents on clinical outcomes of MPN patients affected by the coronavirus disease 2019 (COVID-19). Design: This is an observational study. Methods: We specifically searched and analyzed MPN patients collected by EPICOVIDEHA online registry, which includes individuals with hematological malignancies diagnosed with COVID-19 since February 2020. Results: Overall, 398 patients with MPN were observed for a median of 76 days [interquartile range (IQR): 19–197] after detection of SARS-CoV2 infection. Median age was 69 years (IQR: 58–77) and 183 individuals (46%) had myelofibrosis (MF). Overall, 121 patients (30%) of the whole cohort received immunosuppressive therapies including steroids, immunomodulatory drugs, or JAK inhibitors. Hospitalization and consecutive admission to intensive care unit was required in 216 (54%) and 53 patients (13%), respectively. Risk factors for hospital admission were identified by multivariable logistic regression and include exposure to immunosuppressive therapies [odds ratio (OR): 2.186; 95% confidence interval (CI): 1.357–3.519], age ⩾70 years, and comorbidities. The fatality rate was 22% overall and the risk of death was independently increased by age ⩾70 years [hazard ratio (HR): 2.191; 95% CI: 1.363–3.521], previous comorbidities, and exposure to immunosuppressive therapies before the infection (HR: 2.143; 95% CI: 1.363–3.521). Conclusion: COVID-19 infection led to a particularly dismal outcome in MPN patients receiving immunosuppressive agents or reporting multiple comorbidities. Therefore, specific preventive strategies need to be tailored for such individuals. Plain language summary EPICOVIDEHA registry reports inferior outcomes of COVID-19 in patients with Philadelphia-negative chronic myeloproliferative neoplasms receiving immunosuppressive therapies. Patients with Philadelphia-negative chronic myeloproliferative neoplasms (MPN) incur high rates of infections during the course of their disease. The present study was aimed at assessing which patient characteristics predicted a worse outcome of SARS-COV-2 infection in individuals with MPN. To pursue this objective, the researchers analyzed the data collected by EPICOVIDEHA, an international online registry, which includes individuals with hematological malignancies diagnosed with COVID-19 since February 2020. The database provided clinical data of 398 patients with MPN incurring COVID-19: Patients were mostly elderly (median age was 69 years); Forty-six percent of them were affected by myelofibrosis, which is the most severe MPN; Moreover, 32% were receiving immunosuppressive therapies (JAK inhibitors, such as ruxolitinib, steroids, or immunomodulatory IMID drugs, such as thalidomide) before COVID-19. Hospitalization was required in 54% of the patients, and the risk of being hospitalized for severe COVID-19 was independently predicted by Older age; Comorbidities; Exposure to immunosuppressive therapies. Overall, 22% of MPN patients deceased soon after COVID-19 and the risk of death was independently increased over twofold by Older age; Comorbidities; Exposure to immunosuppressive therapies before the infection. In conclusion, COVID-19 infection led to a particularly dismal outcome in MPN patients receiving immunosuppressive agents, including JAK inhibitors, or reporting multiple comorbidities. Therefore, specific preventive strategies need to be tailored for such individuals.
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| 35. |
- Mckenzie, M., et al.
(författare)
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The complex stellar system M 22 : constraining the chemical enrichment from AGB stars using magnesium isotope ratios
- 2023
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press. - 0035-8711 .- 1365-2966. ; 527:3, s. 7940-7955
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Tidskriftsartikel (refereegranskat)abstract
- The complex star cluster M 22 (NGC 6656) provides a unique opportunity for studying the slow neutron capture (s-)process nucleosynthesis at low metallicity due to its two stellar groups with distinct iron-peak and neutron capture element abundances. Previous studies attribute these abundance differences to pollution from 3 − 6 M asymptotic giant branch (AGB) stars which produce significant quantities of the neutron-rich Mg isotopes 25Mg and 26Mg. We report the first-ever measurements of Mg isotopic abundance ratios at [Fe/H] ∼ −2 in a globular cluster-like system using very high-resolution and signal-to-noise spectra (R = 110 000, S/N = 300 per pixel at 514 nm) from the VLT/UVES spectrograph for six stars; three in each s-process group. Despite the presence of star-to-star variations in 24Mg, 25Mg, and 26Mg, we find no correlation with heavy element abundances, implying that the nucleosynthetic source of s-process enrichment must not influence Mg isotope ratios. Instead, a key result of this work is that we identify correlations between 26Mg/24Mg and some light elements. Using a custom suite of AGB nucleosynthesis yields tailored to the metallicity of M 22, we find that low mass (∼ 1−3 M) AGB stars are capable of reproducing the observed s-process abundances of M 22 and that the absence of any difference in Mg isotope ratios between the two s-process groups precludes AGBs with masses above ∼ 3 M. This places tighter constraints on possible formation scenarios and suggests an age difference of at least ∼ 280−480 Myr between the two populations which is independent of isochrone fitting.
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| 36. |
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| 37. |
- Pelaz, B, et al.
(författare)
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Diverse Applications of Nanomedicine
- 2017
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Ingår i: ACS nano. - : American Chemical Society (ACS). - 1936-086X .- 1936-0851. ; 11:3, s. 2313-2381
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Tidskriftsartikel (refereegranskat)
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| 38. |
- Petursdottir, Dagbjort H., et al.
(författare)
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Early-Life Human Microbiota Associated With Childhood Allergy Promotes the T Helper 17 Axis in Mice
- 2017
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Ingår i: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- The intestinal microbiota influences immune maturation during childhood, and is implicated in early-life allergy development. However, to directly study intestinal microbes and gut immune responses in infants is difficult. To investigate how different types of early-life gut microbiota affect immune development, we collected fecal samples from children with different allergic heredity (AH) and inoculated germ-free mice. Immune responses and microbiota composition were evaluated in the offspring of these mice. Microbial composition in the small intestine, the cecum and the colon were determined by 16S rRNA sequencing. The intestinal microbiota differed markedly between the groups of mice, but only exposure to microbiota associated with AH and known future allergy in children resulted in a T helper 17 (Th17)-signature, both systemically and in the gut mucosa in the mouse offspring. These Th17 responses could be signs of a particular microbiota and a shift in immune development, ultimately resulting in an increased risk of allergy.
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| 39. |
- Tunik, S P, et al.
(författare)
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Chiral hexarhodium clusters containing heterobidentate phosphine ligands, a structural and reactivity study
- 2003
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Ingår i: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9234. ; :12, s. 2457-2467
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Tidskriftsartikel (refereegranskat)abstract
- Some intrinsically chiral [Rh6(CO)14(µ,2-PX)] clusters have been synthesized, beginning with reactions of [Rh6(CO)16–x(NCMe)x](x= 1, 2) with PX, where PX represents the bidentate bridging ligands diphenyl(benzothienyl)phosphine (1), diphenyl(2-thienyl)phosphine (2), di(2-thienyl)phenylphosphine (3), tris(2-thienyl)phosphine (4), diphenyl(2-pyridyl)phosphine (5) and diphenylvinylphosphine (6). The ligand tris(2-furyl)phosphine (7) shows no bridging capability. When x= 1 the initial products are the clusters [Rh6(CO)15(1-PX)] which undergo spontaneous CO loss to form [Rh6(CO)14(µ,2-PX)]. The structures of the [Rh6(CO)15(1-PX)] clusters have been elucidated by IR, NMR spectroscopy and FAB-MS spectrometry, and have been found to involve phosphorus atom coordination to a rhodium atom. In addition, the solid state structures of the [Rh6(CO)14(µ,2-Ph2P(2-benzothienyl))](8), [Rh6(CO)14(µ,2-Ph2P(2-thienyl))](9), [Rh6(CO)14(µ,2-PhP(2-thienyl)2)](10) and [Rh6(CO)14(µ,2-Ph2P(pyridyl))](12) clusters have been determined by X-ray crystallography. The various types of chirality exhibited by these clusters are discussed. A simple model is proposed to account for the ratios of stereochemical isomers found in the Rh6(CO)14(µ,2-PhP(2-thienyl)2 cluster. The kinetics of formation of the bridged clusters from the monosubstituted [Rh6(CO)15(1-PX)] clusters have been studied.
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| 40. |
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