| 1. |
|
|
| 2. |
- Pelaz, B, et al.
(författare)
-
Diverse Applications of Nanomedicine
- 2017
-
Ingår i: ACS nano. - : American Chemical Society (ACS). - 1936-086X .- 1936-0851. ; 11:3, s. 2313-2381
-
Tidskriftsartikel (refereegranskat)
|
|
| 3. |
- Cugno, G., et al.
(författare)
-
A search for accreting young companions embedded in circumstellar disks High-contrast H alpha imaging with VLT/SPHERE
- 2019
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 622
-
Tidskriftsartikel (refereegranskat)abstract
- Context. In recent years, our understanding of giant planet formation progressed substantially. There have even been detections of a few young protoplanet candidates still embedded in the circumstellar disks of their host stars. The exact physics that describes the accretion of material from the circumstellar disk onto the suspected circumplanetary disk and eventually onto the young, forming planet is still an open question.Aims. We seek to detect and quantify observables related to accretion processes occurring locally in circumstellar disks, which could be attributed to young forming planets. We focus on objects known to host protoplanet candidates and/or disk structures thought to be the result of interactions with planets.Methods. We analyzed observations of six young stars (age 3.5-10 Myr) and their surrounding environments with the SPHERE/ZIMPOL instrument on the Very Large Telescope (VLT) in the H alpha filter (656 nm) and a nearby continuum filter (644.9 nm). We applied several point spread function (PSF) subtraction techniques to reach the highest possible contrast near the primary star, specifically investigating regions where forming companions were claimed or have been suggested based on observed disk morphology.Results. We redetect the known accreting M-star companion HD142527 B with the highest published signal to noise to date in both H alpha and the continuum. We derive new astrometry (r = 62.8(-2.7)(+2.1)mas and PA = (98.7 +/- 1.8)degrees) and photometry (Delta N_Ha = 6.3-(+0.2)(0.3) mag, Delta B_Ha = 6.7 +/- 0.2 mag and Delta Cnt_Ha= 7.3(-0.2)(+0.3) mag) for the companion in agreement with previous studies, and estimate its mass accretion rate (M approximate to 1-2 x 10(-10) M-circle dot yr(-1)). A faint point-like source around HD135344 B (SA0206462) is also investigated, but a second deeper observation is required to reveal its nature. No other companions are detected. In the framework of our assumptions we estimate detection limits at the locations of companion candidates around HD100546, HD169142, and MWC 758 and calculate that processes involving Ha fluxes larger than similar to 8 x 10(-14)-10(-15) erg s(-1) cm(-2) (M > 10(-10)-10(-12) M-circle dot yr(-1)) can be excluded. Furthermore, flux upper limits of similar to 10(-14)-10(-15)erg s(-1) cm(-2) (M < 10(-11) -10(-12)M(circle dot )yr(-1)) are estimated within the gaps identified in the disks surrounding HD135344 B and TW Hya. The derived luminosity limits exclude H alpha signatures at levels similar to those previously detected for the accreting planet candidate LkCa15 b.
|
|
| 4. |
- Bonavita, M., et al.
(författare)
-
New binaries from the SHINE survey
- 2022
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 663
-
Tidskriftsartikel (refereegranskat)abstract
- We present the multiple stellar systems observed within the SpHere INfrared survey for Exoplanet (SHINE). SHINE searched for sub-stellar companions to young stars using high contrast imaging. Although stars with known stellar companions within the SPHERE field of view (< 5.5 arcsec) were removed from the original target list, we detected additional stellar companions to 78 of the 463 SHINE targets observed so far. Twenty-seven per cent of the systems have three or more components. Given the heterogeneity of the sample in terms of observing conditions and strategy, tailored routines were used for data reduction and analysis, some of which were specifically designed for these datasets. We then combined SPHERE data with literature and archival data, TESS light curves, and Gaia parallaxes and proper motions for an accurate characterisation of the systems. Combining all data, we were able to constrain the orbits of 25 systems. We carefully assessed the completeness of our sample for separations between 50–500 mas (corresponding to periods of a few years to a few decades), taking into account the initial selection biases and recovering part of the systems excluded from the original list due to their multiplicity. This allowed us to compare the binary frequency for our sample with previous studies and highlight interesting trends in the mass ratio and period distribution. We also found that, when such an estimate was possible, the values of the masses derived from dynamical arguments were in good agreement with the model predictions. Stellar and orbital spins appear fairly well aligned for the 12 stars that have enough data, which favours a disk fragmentation origin. Our results highlight the importance of combining different techniques when tackling complex problems such as the formation of binaries and show how large samples can be useful for more than one purpose.
|
|
| 5. |
- Ittermann, T., et al.
(författare)
-
Standardized Map of Iodine Status in Europe
- 2020
-
Ingår i: Thyroid. - : Mary Ann Liebert Inc. - 1050-7256 .- 1557-9077. ; 30:9
-
Tidskriftsartikel (refereegranskat)abstract
- Background:Knowledge about the population's iodine status is important, because it allows adjustment of iodine supply and prevention of iodine deficiency. The validity and comparability of iodine-related population studies can be improved by standardization, which was one of the goals of the EUthyroid project. The aim of this study was to establish the first standardized map of iodine status in Europe by using standardized urinary iodine concentration (UIC) data. Materials and Methods:We established a gold-standard laboratory in Helsinki measuring UIC by inductively coupled plasma mass spectrometry. A total of 40 studies from 23 European countries provided 75 urine samples covering the whole range of concentrations. Conversion formulas for UIC derived from the gold-standard values were established by linear regression models and were used to postharmonize the studies by standardizing the UIC data of the individual studies. Results:In comparison with the EUthyroid gold-standard, mean UIC measurements were higher in 11 laboratories and lower in 10 laboratories. The mean differences ranged from -36.6% to 49.5%. Of the 40 postharmonized studies providing data for the standardization, 16 were conducted in schoolchildren, 13 in adults, and 11 in pregnant women. Median standardized UIC was <100 mu g/L in 1 out of 16 (6.3%) studies in schoolchildren, while in adults 7 out of 13 (53.8%) studies had a median standardized UIC <100 mu g/L. Seven out of 11 (63.6%) studies in pregnant women revealed a median UIC Conclusions:We demonstrate that iodine deficiency is still present in Europe, using standardized data from a large number of studies. Adults and pregnant women, particularly, are at risk for iodine deficiency, which calls for action. For instance, a more uniform European legislation on iodine fortification is warranted to ensure that noniodized salt is replaced by iodized salt more often. In addition, further efforts should be put on harmonizing iodine-related studies and iodine measurements to improve the validity and comparability of results.
|
|
| 6. |
- Gratton, R., et al.
(författare)
-
Investigating three Sirius-like systems with SPHERE
- 2021
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 646
-
Tidskriftsartikel (refereegranskat)abstract
- Context. Sirius-like systems are relatively wide binaries with a separation from a few to hundreds of au; they are composed of a white dwarf (WD) and a companion of a spectral type earlier than M0. Here we consider main sequence (MS) companions, where the WD progenitor evolves in isolation, but its wind during the former asymptotic giant branch (AGB) phase pollutes the companion surface and transfers some angular momentum. They are rich laboratories to constrain stellar models and binary evolution.Aims. Within the SpHere INfrared survey for Exoplanet survey that uses the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument at the Very Large Telescope, our goal is to acquire high contrast multi-epoch observations of three Sirius-like systems, HD 2133, HD 114174, and CD-56 7708 and to combine this data with archive high resolution spectra of the primaries, TESS archive, and literature data.Methods. These WDs are easy targets for SPHERE and were used as spectrophotometric standards. We performed very accurate abundance analyses for the MS stars using methods considered for solar analogs. Whenever possible, WD parameters and orbits were obtained using Monte Carlo Markov chain methods.Results. We found brighter J and K magnitudes for HD 114174B than obtained previously and extended the photometry down to 0.95 μm. Our new data indicate a higher temperature and then shorter cooling age (5.57 ± 0.02 Gyr) and larger mass (0.75 ± 0.03 M⊙) for this WD than previously assumed. Together with the oldest age for the MS star connected to the use of the Gaia DR2 distance, this solved the discrepancy previously found with the age of the MS star. The two other WDs are less massive, indicating progenitors of ∼1.3 M⊙ and 1.5 − 1.8 M⊙ for HD 2133B and CD-56 7708B, respectively. In spite of the rather long periods, we were able to derive useful constraints on the orbit for HD 114174 and CD-56 7708. They are both seen close to edge-on, which is in agreement with the inclination of the MS stars that are obtained coupling the rotational periods, stellar radii, and the projected rotational velocity from spectroscopy. The composition of the MS stars agrees fairly well with expectations from pollution by the AGB progenitors of the WDs: HD 2133A has a small enrichment of n-capture elements, which is as expected for pollution by an AGB star with an initial mass < 1.5 M⊙; CD-56 7708A is a previously unrecognized mild Ba-star, which is also expected due to pollution by an AGB star with an initial mass in the range of 1.5 − 3.0 M⊙; and HD 114174 has a very moderate excess of n-capture elements, which is in agreement with the expectation for a massive AGB star to have an initial mass > 3.0 M⊙.Conclusions. On the other hand, none of these stars show the excesses of C that are expected to go along with those of n-capture elements. This might be related to the fact that these stars are at the edges of the mass range where we expect nucleosynthesis related to thermal pulses. More work, both theoretical and observational, is required to better understand this issue.
|
|
| 7. |
- Russell, Andrew J.C., et al.
(författare)
-
Regulators of male and female sexual development are critical for the transmission of a malaria parasite
- 2023
-
Ingår i: Cell Host and Microbe. - : Cell Press. - 1931-3128 .- 1934-6069. ; 31:2, s. 305-319.e10
-
Tidskriftsartikel (refereegranskat)abstract
- Malaria transmission to mosquitoes requires a developmental switch in asexually dividing blood-stage parasites to sexual reproduction. In Plasmodium berghei, the transcription factor AP2-G is required and sufficient for this switch, but how a particular sex is determined in a haploid parasite remains unknown. Using a global screen of barcoded mutants, we here identify genes essential for the formation of either male or female sexual forms and validate their importance for transmission. High-resolution single-cell transcriptomics of ten mutant parasites portrays the developmental bifurcation and reveals a regulatory cascade of putative gene functions in the determination and subsequent differentiation of each sex. A male-determining gene with a LOTUS/OST-HTH domain as well as the protein interactors of a female-determining zinc-finger protein indicate that germ-granule-like ribonucleoprotein complexes complement transcriptional processes in the regulation of both male and female development of a malaria parasite.
|
|
| 8. |
- Svensson, Liz, et al.
(författare)
-
Cartilage oligomeric matrix protein-deficient mice have normal skeletal development.
- 2002
-
Ingår i: Molecular and Cellular Biology. - 0270-7306. ; 22:12, s. 4366-4371
-
Tidskriftsartikel (refereegranskat)abstract
- Cartilage oligomeric matrix protein (COMP) belongs to the thrombospondin family and is a homopentamer primarily expressed in cartilage. Mutations in the COMP gene result in the autosomal dominant chondrodysplasias pseudoachondroplasia (PSACH) and some types of multiple epiphyseal dysplasia (MED), which are characterized by mild to severe short-limb dwarfism and early-onset osteoarthritis. We have generated COMP-null mice to study the role of COMP in vivo. These mice show no anatomical, histological, or ultrastructural abnormalities and show none of the clinical signs of PSACH or MED. Northern blot analysis and immunohistochemical analysis of cartilage indicate that the lack of COMP is not compensated for by any other member of the thrombospondin family. The results also show that the phenotype in PSACH/MED cartilage disorders is not caused by the reduced amount of COMP.
|
|
| 9. |
|
|
| 10. |
- Xu, Jianliang, et al.
(författare)
-
Protective functions of ZO-2/Tjp2 expressed in hepatocytes and cholangiocytes against liver injury and cholestasis
- 2021
-
Ingår i: Gastroenterology. - : Elsevier BV. - 1528-0012 .- 0016-5085. ; 160:6, s. 2103-2118
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND & AIMS: Liver tight junctions (TJs) establish tissue barriers that isolate bile from the blood circulation. TJP2/ZO-2-inactivating mutations cause progressive cholestatic liver disease in humans. Since the underlying mechanisms remain elusive, we characterized mice with liver-specific inactivation of Tjp2.METHODS: Tjp2 was deleted in hepatocytes, cholangiocytes, or both. Effects on the liver were assessed by biochemical analyses of plasma, liver and bile and .by EM, histology and immunostaining. TJ barrier permeability was evaluated using FITC-Dextran (4kDa). Cholic acid (CA) diet was used to assess susceptibility to liver injury.RESULTS: Liver-specific deletion of Tjp2 resulted in lower Cldn1 protein levels, minor changes to the TJ, dilated canaliculi, lower microvilli density and aberrant Radixin and BSEP distribution, without an overt increase in TJ permeability. Hepatic Tjp2-defcient mice presented with mild progressive cholestasis with lower expression levels of bile acid (BA) transporter Abcb11/Bsep and detoxification enzyme Cyp2b10. A CA-diet tolerated by control mice caused severe cholestasis and liver necrosis in Tjp2-deficient animals. TCPOBOP ameliorated CA-induced injury by enhancing Cyp2b10 expression and ursodeoxycholic acid provided partial improvement. Inactivating Tjp2 separately in hepatocytes or cholangiocytes only showed mild CA-induced liver injury.CONCLUSION: Tjp2 is required for normal cortical distribution of Radixin, canalicular volume regulation and microvilli density, Its inactivation deregulated expression of Cldn1 and key BA transporters and detoxification enzymes. The mice provide a novel animal model for cholestatic liver disease caused by TJP2-inactivating mutations in humans.
|
|
