| 1. |
|
|
| 2. |
- Anand, Kanwlajeet J. S., et al.
(författare)
-
Assessment of continuous pain in newborns admitted to NICUs in 18 European countries
- 2017
-
Ingår i: Acta Paediatrica. - : John Wiley & Sons. - 0803-5253 .- 1651-2227. ; 106:8, s. 1248-1259
-
Tidskriftsartikel (refereegranskat)abstract
- Aim: Continuous pain occurs routinely, even after invasive procedures, or inflammation and surgery, but clinical practices associated with assessments of continuous pain remain unknown.Methods: A prospective cohort study in 243 Neonatal Intensive Care Units (NICUs) from 18 European countries recorded frequency of pain assessments, use of mechanical ventilation, sedation, analgesia, or neuromuscular blockade for each neonate upto 28 days after NICU admission.Results: Only 2113/6648 (31·8%) of neonates received assessments of continuous pain, occurring variably among tracheal ventilation (TrV, 46·0%), noninvasive ventilation (NiV, 35·0%), and no ventilation (NoV, 20·1%) groups (p<0·001). Daily assessments for continuous pain occurred in only 10·4% of all neonates (TrV: 14·0%, NiV: 10·7%, NoV: 7·6%; p<0·001). More frequent assessments of continuous pain occurred in NICUs with pain guidelines, nursing champions, and surgical admissions prompted (all p<0·01), and for newborns <32 weeks gestational age, those requiring ventilation, or opioids, sedatives-hypnotics, general anesthetics (O-SH-GA) (all p<0·001), or surgery (p=0·028). Use of O-SH-GA drugs increased the odds for pain assessment in the TrV (OR:1·60, p<0·001) and NiV groups (OR:1·40, p<0·001).Conclusion: Assessments of continuous pain occurred in less than one-third of NICU admissions, and daily in only 10% of neonates. NICU clinical practices should consider including routine assessments of continuous pain in newborns.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Bignert, Anders, et al.
(författare)
-
Comments Concerning the National Swedish Contaminant Monitoring Programme in Marine Biota, 2015
- 2015
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The environmental toxicants examined in this report can be classified into five groups – heavy metals, chlorinated compounds, brominated flame retardants, polyaromatic hydrocarbons and perfluorinated compounds. Each of these contaminants have been examined from various sites for up to six different fish species, in blue mussels, and in guillemot eggs, for varying lengths of time. The following summary examines overall trends, spatial and temporal, for the five groups.Condition and Fat ContentCondition and fat content in different species tended to follow the same pattern at the same sites, with a few exceptions. Most of the fish species generally displayed a decreasing trend in both condition and fat content at most sites examined. Exceptions to this were increases in condition factor seen in cod liver at Fladen, perch muscle at Kvädöfjärden, and for herring at Ängskärsklubb in spring. Also, an increase in fat content was seen during the most recent ten years for herring at Ängskärsklubb in spring. There were also some sites where no log linear trends were seen.Heavy MetalsDue to a change in methods for metal analysis (not mercury) in 2004, values between 2003 and 2007 should be interpreted with care. From 2009 metals are analyzed at ACES, Stockholm University.Generally, higher mercury concentrations are found in the Bothnian Bay, but also from one station in the Northern parts of Baltic Proper, compared to other parts of the Swedish coastline. The time series show varying concentrations over the study period. The longer time series in guillemot egg and spring-caught herring from the southern Bothnian Sea and southern Baltic Proper show significant decreases of mercury. On the other hand, increasing concentrations are seen in e.g., cod muscle, but the concentrations are fairly low compared to measured concentrations in perch from fresh water and coastal sites. In most cases, the mercury concentrations are above the EQSbiota of 20 ng/g wet weight.Lead is generally decreasing over the study period (in time series of sufficient length), supposedly due to the elimination of lead in gasoline. The highest concentrations are seen in the southern part of the Baltic Sea. Elevated lead concentrations between 2003 and 2007 (e.g. Harufjärden) should be viewed with caution (see above regarding change in analysis methods). Lead concentrations are below the suggested target level at all stations.Cadmium concentrations show varying non-linear trends over the monitored period. It is worth noting that despite several measures taken to reduce discharges of cadmium, generally the most recent concentrations are similar to concentrations measured 30 yearsago in the longer time series. Cadmium concentrations in herring and perch are all below the suggested target level of 160 μg/kg wet weight.The reported nickel concentrations show no consistent decreasing trends. Some series begin with two elevated values that exert a strong leverage effect on the regression line and may give a false impression of decreasing trends. Chromium generally shows decreasing concentrations, possibly explained by a shift in analytical method. The essential trace metals, copper and zinc, show no consistent trends during the monitored period.Generally higher concentrations of arsenic and silver are found along the west coast compared to other parts of the Sweadish coast line. However for silver a few stations in the Bothnian Sea and Bothnian Bay show comparable concentrations to the west coast stations.Chlorinated CompoundsGenerally, a decreasing concentrations were observed for all compounds (DDT’s, PCB’s, HCH’s, HCB) in all species examined, with a few exceptions, such as no change in TCDD-equivalents being seen in herring muscle (except at Änskärsklubb where very high concentrations at the beginning of the sampling period were seen and also at the west coast station Fladen). The longer time-series in guillemot also show a marked decrease in TCDD-equivalents from the start in the late 1960s until about 1985 from where no change occurred for many years, however, during the most recent ten years a decrease in the concentration is seen. Concentrations of DDE and CB-118 are for some species and sites still above their respective target levels.The chlorinated compounds generally show higher concentrations in the Bothnian Sea and/or Baltic Proper when compared to the Bothnian Bay and the Swedish west coast.Brominated Flame RetardantsElevated levels of HBCDD are seen in sites from the Baltic Proper, while the investigated PBDEs show higher concentrations in the Bothnian Bay. In addition, lower concentrations of all investigated PBDEs and HBCDD are seen on the Swedish west coast compared to the east coast. Temporally, significant increases in BDE-47, -99 and -100 have been seen in guillemot eggs since the late 1960s until the early 1990s, where concentrations then began to show decreases. Also, the concentration of HBCDD in guillemot eggs shows a decrease during the most recent ten years. For fish and blue mussels, BDE-47, -99, and -153 decreased at some sites and showed no trend at other sites. The concentration of HBCDD in fish and blue mussels showed inconsistent trends. The concentration of HBCDD is below the EQSbiota of 167 μg/kg wet weight for all fish species from all areas, while the concentration of BDE-47 alone is above the EQSbiota for sumPBDE of 0.0085 ng/g wet weight.PAHsOnly blue mussels have been examined for spatial differences in PAH concentrations. Concentration of ΣPAH was found to be higher from Kvädöfjärden in the Baltic Proper compared to stations at the West coast, but individual PAHs showed varying spatial patterns. Over time, acenaphthalene was rarely found above the detection limit. Significant decreasing trends were observed for ΣPAH, chrysene, fluoranthene and pyrene at Fjällbacka; for naphthalene at Kvädöfjärden; and for pyrene at Fladen.All time series where concentrations of various PAHs were compared with the target value based on OSPAR Ecological Assessment Criteria, or EC Environmental Quality Standards were below the target value.PFASsPFHxS and PFOS show a similar spatial pattern, but PFOS concentrations were approximately 25 times higher than PFHxS levels. The distribution of PFOS is quite homogenous along the Swedish coast but with somewhat higher concentrations in the Baltic Proper. PFOS concentrations in guillemot eggs are about 100-200 times higher than in herring liver. An overall increasing concentration of PFOS in guillemot eggs has been observed throughout the whole time period, however, during the most recent ten years, a change of direction is detected. The longer herring time series from Harufjärden, Landsort, and Utlängan show increasing concentrations for PFOS and most carboxylates. For FOSA, on the other hand, decreasing concentrations are seen during the most recent ten years.Organotin compoundsThe majority of the analysed tinorganic compounds showed concentrations below LOQ. However TBT and DPhT showed concentrations above LOQ at all stations with highest reported concentrations in fish from Örefjärden in the northern part of Bothnian Sea.
|
|
| 8. |
- Blasiak, Robert, et al.
(författare)
-
Towards greater transparency and coherence in funding for sustainable marine fisheries and healthy oceans
- 2019
-
Ingår i: Marine Policy. - : Elsevier BV. - 0308-597X .- 1872-9460. ; 107
-
Tidskriftsartikel (refereegranskat)abstract
- This final manuscript in the special issue on Funding for ocean conservation and sustainable fisheries is the result of a dialogue aimed at connecting lead authors of the special issue manuscripts with relevant policymakers and practitioners. The dialogue took place over the course of a two-day workshop in December 2018, and this coda manuscript seeks to distil thinking around a series of key recurring topics raised throughout the workshop. These topics are collected into three broad categories, or needs: 1) a need for transparency, 2) a need for coherence, and 3) a need for improved monitoring of project impacts. While the special issue sought to collect new research into the latest trends and developments in the rapidly evolving world of funding for ocean conservation and sustainable fisheries, the insights collected during the workshop have helped to highlight remaining knowledge gaps. Therefore, each of the three needs identified within this manuscript is followed by a series of questions that the workshop participants identified as warranting further attention as part of a future research agenda. The crosscutting nature of many of the issues raised as well as the rapid pace of change that characterizes this funding landscape both pointed to a broader need for continued dialogue and study that reaches across the communities of research, policy and practice.
|
|
| 9. |
- Carbajal, Ricardo, et al.
(författare)
-
Pain Assessment in Ventilated and Non-Ventilated Neonates in NICUs across Europe : EUROpean Pain Audit in Neonates (EUROPAIN Survey)
- 2014
-
Konferensbidrag (refereegranskat)abstract
- Background: Neonates undergo many painful procedures during their NICU stay. These may include tracheal intubation/ventilation, skin-breaking procedures, drainage/suctioning of body orifices or cavities. Inherent subjectivity and difficulties of neonatal pain assessment contribute to a wide variety of assessment tools and clinical practices. To date, these practices have been not studied at a large scale. OBJECTIVE: To determine current clinical practices for neonatal pain assessment in NICUs across Europe. DESIGN/METHODS: An epidemiological observational study on bedside pain assessment practices collected data for all neonates in participating NICUs until infants left the unit (discharge, death, transfer to another hospital) or for 28 days. Data collection occurred via an online database for 1 month at each NICU. All neonates up to a gestational age of 44 weeks were included. RESULTS: From October 2012 to June 2013, 243 NICUs from 18 European countries collected pain assessment data in 6680 neonates. Of these, 2142 received tracheal ventilation (ventilated) and 4538 had spontaneous breathing or non- invasive ventilation (non-ventilated). The median (IQR) gestational age of ventilated neonates [32.1 (28.1-37.4)] was less than non-ventilated neonates [36.6 (33.6-39.1), p<0.001]. Overall, 58.5% of ventilated neonates and 35.2%% of non-ventilated neonates received bedside pain assessments (p<0.001). CONCLUSIONS: Over half (58.5%) of ventilated neonates and about one third (35.2%) of non-ventilated neonates had pain assessments performed in European NICUs. Wide variations in the methods used and rates of pain assessment exist among countries
|
|
| 10. |
- Carbajal, Ricardo, et al.
(författare)
-
Pain Assessment in Ventilated and Non-Ventilated Neonates in NICUS across Europe : Results from the EUROPAIN Study
- 2016
-
Konferensbidrag (refereegranskat)abstract
- Aim of Investigation: Pain from invasive or noninvasive procedures, mechanical ventilation, or painful medical and surgical conditions is commonplace in neonatal intensive care units (NICUs). While prevention and treatment of neonatal pain seem essential, an adequate analgesic approach cannot be implemented without relevant and timely pain assessments. Data on neonatal pain assessment practices are scarce, with undefined best practices or clinical benefits. We aimed to describe pain assessment practices in 243 NICUs from 18 European countries and to examine the NICU and patient characteristics influencing pain assessments at the bedside.Methods: Demographic data, modes of respiration, use of sedation, analgesia, or neuromuscular blockers, frequency and types of pain assessments were recorded for all newborns during the first 28 days of NICU admission. Multivariable models tested the associations between the performance of pain assessments and center and neonatal factors.Results: Among 6648 neonates enrolled, highest level of ventilation during the study period classified patients into tracheal ventilation (TV, n=2138 [32%]), non-invasive ventilation (NIV, n=1493 [23%]), and spontaneous ventilation groups (SV, n=3017 [45%]). Pain assessments were performed in 1250 (58%), 672 (45%), and 916 (30%) of these groups respectively (p<0.001). Using data from 78,742 patient-days, we found that 2,838 (43%) neonates received 4.3 (5.2) pain assessments per neonate and per day (median (IQR): 2.4 (1-5)), whereas 3810 (57%) neonates did not receive any pain assessments. Pain assessments occurred on every day of the NICU stay in 461/2138 (22%) TV patients, 236/1493 (16%) NIV patients, and 393/3016 (13%) SV patients (p<0.001).Many different pain assessment methods were used; the EDIN scale was used most frequently (42.3% among those who had at least one pain assessment). We analysed 33,625 patient-days in the TV group to test for associations between pain assessment and the use of opioids, sedatives-hypnotics, or general anaesthetics (O-SH-GA). The rates of pain assessments on patient-days with and without O-SH-GA use were, respectively, 57% vs. 43% while receiving mechanical ventilation, and 60% vs. 34% while not receiving mechanical ventilation (both p<0.001). Multivariable analyses showed that NICU-based guidelines, nursing leadership, and increased surgical admissions promoted the use of routine pain assessments (p<0.001). More pain assessments were performed in newborns below 32-weeks gestational age, those with decreased severity of illness, those already intubated at admission, those requiring mechanical or non-invasive ventilation, or surgery, or use of O-SH-GA.Conclusion: Even though pain is considered the 5th vital sign, only 43% of NICU neonates received bedside pain assessments. Clinical practice variability and low rates of pain assessments in NICUS may reflect weaknesses in the current paradigm used for neonatal pain assessments, their subjectivity, lack of inter-rater reliability, and other long-standing concerns. Results suggest that training to improve the rate of pain assessment in NICUs will enhance pain management in NICUs.Trial Registration: ClinicalTrials.gov #NCT01694745
|
|
| 11. |
- Carbajal, Ricardo, et al.
(författare)
-
Pain Assessment In Ventilated And Non-ventilated Neonates In Nicus Across Europe : European Pain Audit In Neonates (europain Survey)
- 2014
-
Ingår i: Archives of Disease in Childhood. - London, United Kingdom : BMJ Publishing Group Ltd. - 0003-9888 .- 1468-2044. ; 99, s. A68-A68
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Neonates undergo many painful procedures during their NICU stay. These may include tracheal intubation/ventilation, skin-breaking procedures, drainage/suctioning of body orifices or cavities. Inherent subjectivity and difficulties of neonatal pain assessment contribute to a wide variety of assessment tools and clinical practices. To date, these practices have been not studied at a large scale.Objective: To determine current clinical practices for neonatal pain assessment in NICUs across Europe.Methods: An epidemiological observational study on bedside pain assessment practices collected data for all neonates in participating NICUs until infants left the unit (discharge, death, transfer to another hospital) or for 28 days. Data collection occurred via an online database for 1 month at each NICU. All neonates up to a gestational age of 44 weeks were included.Results: From October 2012 to June 2013, 243 NICUs from 18 European countries collected pain assessment data in 6680 neonates. Of these, 2142 received tracheal ventilation (TV), 1496 non-invasive ventilation (NIV) and 3042 only spontaneous ventilation (SV). The median (IQR) gestational age of TV, NIV and SV neonates were 32.1 (28.1–37.4), 33.6 (31.0–36.6) and 37.9 (35.0–39.9), respectively (p < 0.001). Overall, 58.5% of TV neonates, 45.0% of NIV neonates and 30.4% of SV neonates received bedside pain assessments (p < 0.001). Fig. shows pain assessments by country.Conclusions: Over half (58.5%) of TV neonates and less than half (45.0%) of NIV neonates had pain assessments performed in European NICUs. Wide variations in the rates of pain assessment exist among countries and an important improvement seems necessary.
|
|
| 12. |
- Carbajal, Ricardo, et al.
(författare)
-
Sedation And Analgesia For Neonates In Nicus Across Europe : The Europain Survey
- 2014
-
Ingår i: Archives of Disease in Childhood. - London, United Kingdom : BMJ Publishing Group Ltd. - 0003-9888 .- 1468-2044. ; 99, s. A64-A64
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Pain and stress induced by mechanical ventilation, invasive procedures, or painful diseases supports the use of sedation/analgesia (S/A) in newborns admitted to Neonatal Intensive Care Units (NICUs). To date, these practices have not been studied at a large scale.Objective: To determine current clinical practices regarding the use of S/A drugs in NICUs across Europe.Methods: This epidemiological observational study on bedside clinical practices regarding S/A collected data for all neonates in participating NICUs until the infant left the unit (discharge, death, transfer) or for up to 28 days. Data collection occurred via an online database for 1 month at each NICU. All neonates up to 44 weeks gestation were included.Results: From October 2012 to June 2013, 243 NICUs from 18 European countries collected data on 6680 eligible neonates. Of these, 2142 received tracheal ventilation (TV), 1496 non-invasive ventilation (NIV) and 3042 only spontaneous ventilation (SV). The median (IQR) gestational age of TV, NIV and SV neonates were 32.1 (28.1–37.4), 33.6 (31.0–36.6) and 37.9 (35.0–39.9), respectively (p < 0.001). Overall, more TV neonates [81.5% (n = 1746)] received S/A drugs than NIV neonates [17.8% (n = 266)] and SV neonates [9.3% (n = 282)]; p < 0.001. Fig. shows the rate of S/A use by country; table shows S/A drugs used.Conclusions: Most ventilated but few non-ventilated neonates (NIV and SV) receive S/A therapy in European NICUs. Wide variations in S/A use, drugs used, and mode of administration (continuous, bolus, or both) exist among countries.
|
|
| 13. |
- Carbajal, Ricardo, et al.
(författare)
-
Sedation and analgesia practices in neonatal intensive care units (EUROPAIN) : results from a prospective cohort study
- 2015
-
Ingår i: The Lancet Respiratory Medicine. - : Elsevier. - 2213-2600 .- 2213-2619. ; 3:10, s. 796-812
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Neonates who are in pain or are stressed during care in the intensive care unit (ICU) are often given sedation or analgesia. We investigated the current use of sedation or analgesia in neonatal ICUs (NICUs) in European countries. Methods: EUROPAIN (EUROpean Pain Audit In Neonates) was a prospective cohort study of the management of sedation and analgesia in patients in NICUs. All neonates admitted to NICUs during 1 month were included in this study. Data on demographics, methods of respiration, use of continuous or intermittent sedation, analgesia, or neuromuscular blockers, pain assessments, and drug withdrawal syndromes were gathered during the first 28 days of admission to NICUs. Multivariable linear regression models and propensity scores were used to assess the association between duration of tracheal ventilation (TV) and exposure to opioids, sedatives-hypnotics, or general anaesthetics in neonates (O-SH-GA). This study is registered with ClinicalTrials.gov, number NCT01694745. Findings: From Oct 1, 2012, to June 30, 2013, 6680 neonates were enrolled in 243 NICUs in 18 European countries. Mean gestational age of these neonates was 35∙0 weeks (SD 4∙6) and birthweight was 2384 g (1007). 2142 (32%) neonates were given TV, 1496 (22%) non-invasive ventilation (NIV), and 3042 (46%) were kept on spontaneous ventilation (SV). 1746 (82%), 266 (18%), and 282 (9%) neonates in the TV, NIV, and SV groups, respectively, were given sedation or analgesia as a continuous infusion, intermittent doses, or both (p<0∙0001). In the participating NICUs, the median use of sedation or analgesia was 89∙3% (70∙0–100) for neonates in the TV group. Opioids were given to 1764 (26%) of 6680 neonates and to 1589 (74%) of 2142 neonates in the TV group. Midazolam was given to 576 (9%) of 6680 neonates and 536 (25%) neonates of 2142 neonates in the TV group. 542 (25%) neonates in the TV group were given neuromuscular blockers, which were administered as continuous infusions to 146 (7%) of these neonates. Pain assessments were recorded in 1250 (58%) of 2138, 672 (45%) of 1493, and 916 (30%) of 3017 neonates in the TV, NIV, and SV groups, respectively (p<0∙0001). In the univariate analysis, neonates given O-SH-GA in the TV group needed a longer duration of TV than did those who were not given O-SH-GA (mean 136∙2 h [SD 173∙1] vs 39∙8 h [94∙7] h; p<0∙0001). Multivariable and propensity score analyses confirmed this association (p<0∙0001). Interpretation: Wide variations in sedation and analgesia practices occur between NICUs and countries. Widespread use of O-SH-GA in intubated neonates might prolong their need for mechanical ventilation, but further research is needed to investigate the therapeutic and adverse effects of O-SH-GA in neonates, and to develop new and safe approaches for sedation and analgesia.
|
|
| 14. |
|
|
| 15. |
- Dunkel, Mathias, et al.
(författare)
-
SuperScent--a database of flavors and scents
- 2009
-
Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 1362-4962 .- 0305-1048. ; 37, s. 291-294
-
Tidskriftsartikel (refereegranskat)abstract
- Volatiles are efficient mediators of chemical communication acting universally as attractant, repellent or warning signal in all kingdoms of life. Beside this broad impact volatiles have in nature, scents are also widely used in pharmaceutical, food and cosmetic industries, so the identification of new scents is of great industrial interest. Despite this importance as well as the vast number and diversity of volatile compounds, there is currently no comprehensive public database providing information on structure and chemical classification of volatiles. Therefore, the database SuperScent was established to supply users with detailed information on the variety of odor components. The version of the database presented here comprises the 2D/3D structures of approximately 2100 volatiles and around 9200 synonyms as well as physicochemical properties, commercial availability and references. The volatiles are classified according to their origin, functionality and odorant groups. The information was extracted from the literature and web resources. SuperScent offers several search options, e.g. name, Pubchem ID number, species, functional groups, or molecular weight. SuperScent is available online at: http://bioinformatics.charite.de/superscent.
|
|
| 16. |
- Eriksson, Daniel, et al.
(författare)
-
GWAS for autoimmune Addison’s disease identifies multiple risk loci and highlights AIRE in disease susceptibility
- 2021
-
Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 12:1
-
Tidskriftsartikel (refereegranskat)abstract
- Autoimmune Addison's disease (AAD) is characterized by the autoimmune destruction of the adrenal cortex. Low prevalence and complex inheritance have long hindered successful genetic studies. We here report the first genome-wide association study on AAD, which identifies nine independent risk loci (P < 5 × 10-8). In addition to loci implicated in lymphocyte function and development shared with other autoimmune diseases such as HLA, BACH2, PTPN22 and CTLA4, we associate two protein-coding alterations in Autoimmune Regulator (AIRE) with AAD. The strongest, p.R471C (rs74203920, OR = 3.4 (2.7-4.3), P = 9.0 × 10-25) introduces an additional cysteine residue in the zinc-finger motif of the second PHD domain of the AIRE protein. This unbiased elucidation of the genetic contribution to development of AAD points to the importance of central immunological tolerance, and explains 35-41% of heritability (h2).
|
|
| 17. |
|
|
| 18. |
- Garatti, A. Caratti o., et al.
(författare)
-
The GRAVITY young stellar object survey: II. First spatially resolved observations of the CO bandhead emission in a high-mass YSO
- 2020
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 635
-
Tidskriftsartikel (refereegranskat)abstract
- Context. The inner regions of the discs of high-mass young stellar objects (HMYSOs) are still poorly known due to the small angular scales and the high visual extinction involved. Aims. We deploy near-infrared spectro-interferometry to probe the inner gaseous disc in HMYSOs and investigate the origin and physical characteristics of the CO bandhead emission (2.3-2.4 m). Methods. We present the first GRAVITY/VLTI observations at high spectral (R = 4000) and spatial (mas) resolution of the CO overtone transitions in NGC2024 IRS 2. Results. The continuum emission is resolved in all baselines and is slightly asymmetric, displaying small closure phases (8). Our best ellipsoid model provides a disc inclination of 34 1, a disc major axis position angle (PA) of 166 1, and a disc diameter of 3:99 0:09 mas (or 1.69 0.04 au, at a distance of 423 pc). The small closure phase signals in the continuum are modelled with a skewed rim, originating from a pure inclination effect. For the first time, our observations spatially and spectrally resolve the first four CO bandheads. Changes in visibility, as well as differential and closure phases across the bandheads are detected. Both the size and geometry of the CO-emitting region are determined by fitting a bidimensional Gaussian to the continuum-compensated CO bandhead visibilities. The CO-emitting region has a diameter of 2.740:08 0:07 mas (1.16 0.03 au), and is located in the inner gaseous disc, well within the dusty rim, with inclination and PA matching the dusty disc geometry, which indicates that both dusty and gaseous discs are coplanar. Physical and dynamical gas conditions are inferred by modelling the CO spectrum. Finally, we derive a direct measurement of the stellar mass of M 14:7 M by combining our interferometric and spectral modelling results.
|
|
| 19. |
- Garcia-Lopez, R., et al.
(författare)
-
A measure of the size of the magnetospheric accretion region in TW Hydrae
- 2020
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 584:7822, s. 547-550
-
Tidskriftsartikel (refereegranskat)abstract
- Stars form by accreting material from their surrounding disks. There is a consensus that matter flowing through the disk is channelled onto the stellar surface by the stellar magnetic field. This is thought to be strong enough to truncate the disk close to the corotation radius, at which the disk rotates at the same rate as the star. Spectro-interferometric studies in young stellar objects show that hydrogen emission (a well known tracer of accretion activity) mostly comes from a region a few milliarcseconds across, usually located within the dust sublimation radius1–3. The origin of the hydrogen emission could be the stellar magnetosphere, a rotating wind or a disk. In the case of intermediate-mass Herbig AeBe stars, the fact that Brackett γ (Brγ) emission is spatially resolved rules out the possibility that most of the emission comes from the magnetosphere4–6 because the weak magnetic fields (some tenths of a gauss) detected in these sources7,8 result in very compact magnetospheres. In the case of T Tauri sources, their larger magnetospheres should make them easier to resolve. The small angular size of the magnetosphere (a few tenths of a milliarcsecond), however, along with the presence of winds9,10 make the interpretation of the observations challenging. Here we report optical long-baseline interferometric observations that spatially resolve the inner disk of the T Tauri star TW Hydrae. We find that the near-infrared hydrogen emission comes from a region approximately 3.5 stellar radii across. This region is within the continuum dusty disk emitting region (7 stellar radii across) and also within the corotation radius, which is twice as big. This indicates that the hydrogen emission originates in the accretion columns (funnel flows of matter accreting onto the star), as expected in magnetospheric accretion models, rather than in a wind emitted at much larger distance (more than one astronomical unit).
|
|
| 20. |
- Koch, Sina, et al.
(författare)
-
NRP1 Presented in trans to the Endothelium Arrests VEGFR2 Endocytosis, Preventing Angiogenic Signaling and Tumor Initiation
- 2014
-
Ingår i: Developmental Cell. - : Elsevier BV. - 1534-5807 .- 1878-1551. ; 28:6, s. 633-646
-
Tidskriftsartikel (refereegranskat)abstract
- Neuropilin 1 (NRP1) modulates angiogenesis by binding vascular endothelial growth factor (VEGF) and its receptor, VEGFR2. We examined the consequences when VEGFR2 and NRP1 were expressed on the same cell (cis) or on different cells (trans). In cis, VEGF induced rapid VEGFR2/NRP1 complex formation and internalization. In trans, complex formation was delayed and phosphorylation of phospholipase C gamma (PLC gamma) and extracellular regulated kinase 2 (ERK2) was prolonged, whereas ERK1 phosphorylation was reduced. Trans complex formation suppressed initiation and vascularization of NRP1-expressing mouse fibrosarcoma and melanoma. Suppression in trans required high-affinity, steady-state binding of VEGF to NRP1, which was dependent on the NRP1 C-terminal domain. Compatible with a trans effect of NRP1, quiescent vasculature in the developing retina showed continuous high NRP1 expression, whereas angiogenic sprouting occurred where NRP1 levels fluctuated between adjacent endothelial cells. Therefore, through communication in trans, NRP1 can modulate VEGFR2 signaling and suppress angiogenesis.
|
|
| 21. |
- Koutoulaki, M., et al.
(författare)
-
The GRAVITY young stellar object survey: IV. The CO overtone emission in 51 Oph at sub-au scales
- 2021
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 645
-
Tidskriftsartikel (refereegranskat)abstract
- Context. 51 Oph is a Herbig Ae/Be star that exhibits strong near-infrared CO ro-vibrational emission at 2.3 μm, most likely originating in the innermost regions of a circumstellar disc. Aims. We aim to obtain the physical and geometrical properties of the system by spatially resolving the circumstellar environment of the inner gaseous disc. Methods. We used the second-generation Very Large Telescope Interferometer instrument GRAVITY to spatially resolve the continuum and the CO overtone emission. We obtained data over 12 baselines with the auxiliary telescopes and derive visibilities, and the differential and closure phases as a function of wavelength. We used a simple local thermal equilibrium ring model of the CO emission to reproduce the spectrum and CO line displacements. Results. Our interferometric data show that the star is marginally resolved at our spatial resolution, with a radius of ∼10.58 ± 2.65R·. The K-band continuum emission from the disc is inclined by 63° ± 1°, with a position angle of 116° ± 1°, and 4 ± 0.8 mas (0.5 ± 0.1 au) across. The visibilities increase within the CO line emission, indicating that the CO is emitted within the dust-sublimation radius. By modelling the CO bandhead spectrum, we derive that the CO is emitted from a hot (T = 1900-2800 K) and dense (NCO = (0.9-9) × 1021 cm-2) gas. The analysis of the CO line displacement with respect to the continuum allows us to infer that the CO is emitted from a region 0.10 ± 0.02 au across, well within the dust-sublimation radius. The inclination and position angle of the CO line emitting region is consistent with that of the dusty disc. Conclusions. Our spatially resolved interferometric observations confirm the CO ro-vibrational emission within the dust-free region of the inner disc. Conventional disc models exclude the presence of CO in the dust-depleted regions of Herbig AeBe stars. Ad hoc models of the innermost disc regions, that can compute the properties of the dust-free inner disc, are therefore required.
|
|
| 22. |
- Lacour, S., et al.
(författare)
-
The mass of β Pictoris c from β Pictoris b orbital motion
- 2021
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 654
-
Tidskriftsartikel (refereegranskat)abstract
- Aims. We aim to demonstrate that the presence and mass of an exoplanet can now be effectively derived from the astrometry of another exoplanet.Methods. We combined previous astrometry of β Pictoris b with a new set of observations from the GRAVITY interferometer. The orbital motion of β Pictoris b is fit using Markov chain Monte Carlo simulations in Jacobi coordinates. The inner planet, β Pictoris c, was also reobserved at a separation of 96 mas, confirming the previous orbital estimations.Results. From the astrometry of planet b only, we can (i) detect the presence of β Pictoris c and (ii) constrain its mass to 10.04(-3.10)(+4.53) M-Jup. If one adds the astrometry of β Pictoris c, the mass is narrowed down to 9.15(-1.06)(+1.08) M-Jup. The inclusion of radial velocity measurements does not affect the orbital parameters significantly, but it does slightly decrease the mass estimate to 8.89(-0.75)(+0.75) M-Jup. With a semimajor axis of 2.68 +/- 0.02 au, a period of 1221 +/- 15 days, and an eccentricity of 0.32 +/- 0.02, the orbital parameters of β Pictoris c are now constrained as precisely as those of β Pictoris b. The orbital configuration is compatible with a high-order mean-motion resonance (7:1). The impact of the resonance on the planets' dynamics would then be negligible with respect to the secular perturbations, which might have played an important role in the eccentricity excitation of the outer planet.
|
|
| 23. |
- Lagrange, A. M., et al.
(författare)
-
Unveiling the beta Pictoris system, coupling high contrast imaging, interferometric, and radial velocity data
- 2020
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 642
-
Tidskriftsartikel (refereegranskat)abstract
- Context. The nearby and young beta Pictoris system hosts a well resolved disk, a directly imaged massive giant planet orbiting at similar or equal to 9 au, as well as an inner planet orbiting at similar or equal to 2.7 au, which was recently detected through radial velocity (RV). As such, it offers several unique opportunities for detailed studies of planetary system formation and early evolution.Aims. We aim to further constrain the orbital and physical properties of beta Pictoris b and c using a combination of high contrast imaging, long base-line interferometry, and RV data. We also predict the closest approaches or the transit times of both planets, and we constrain the presence of additional planets in the system.Methods. We obtained six additional epochs of SPHERE data, six additional epochs of GRAVITY data, and five additional epochs of RV data. We combined these various types of data in a single Markov-chain Monte Carlo analysis to constrain the orbital parameters and masses of the two planets simultaneously. The analysis takes into account the gravitational influence of both planets on the star and hence their relative astrometry. Secondly, we used the RV and high contrast imaging data to derive the probabilities of presence of additional planets throughout the disk, and we tested the impact of absolute astrometry.Results. The orbital properties of both planets are constrained with a semi-major axis of 9.8 0.4 au and 2.7 +/- 0.02 au for b and c, respectively, and eccentricities of 0.09 +/- 0.1 and 0.27 +/- 0.07, assuming the HIPPARCOS distance. We note that despite these low fitting error bars, the eccentricity of beta Pictoris c might still be over-estimated. If no prior is provided on the mass of beta Pictoris b, we obtain a very low value that is inconsistent with what is derived from brightness-mass models. When we set an evolutionary model motivated prior to the mass of beta Pictoris b, we find a solution in the 10-11 M-Jup range. Conversely, beta Pictoris c's mass is well constrained, at 7.8 +/- 0.4 M-Jup, assuming both planets are on coplanar orbits. These values depend on the assumptions on the distance of the beta Pictoris system. The absolute astrometry HIPPARCOS-Gaia data are consistent with the solutions presented here at the 2 sigma level, but these solutions are fully driven by the relative astrometry plus RV data. Finally, we derive unprecedented limits on the presence of additional planets in the disk. We can now exclude the presence of planets that are more massive than about 2.5 M-Jup closer than 3 au, and more massive than 3.5 M-Jup between 3 and 7.5 au. Beyond 7.5 au, we exclude the presence of planets that are more massive than 1-2 M-Jup.Conclusions. Combining relative astrometry and RVs allows one to precisely constrain the orbital parameters of both planets and to give lower limits to potential additional planets throughout the disk. The mass of beta Pictoris c is also well constrained, while additional RV data with appropriate observing strategies are required to properly constrain the mass of beta Pictoris b.
|
|
| 24. |
|
|
| 25. |
- Mathurin, Frédéric A., et al.
(författare)
-
High cesium concentrations in groundwater in the upper 1.2km of fractured crystalline rock - Influence of groundwater origin and secondary minerals
- 2014
-
Ingår i: Geochimica et Cosmochimica Acta. - : Elsevier Ltd. - 0016-7037 .- 1872-9533. ; 132, s. 187-213
-
Tidskriftsartikel (refereegranskat)abstract
- Dissolved and solid phase cesium (Cs) was studied in the upper 1.2km of a coastal granitoid fracture network on the Baltic Shield (Äspö Hard Rock Laboratory and Laxemar area, SE Sweden). There unusually high Cs concentrations (up to 5-6μgL-1) occur in the low-temperature (<20°C) groundwater. The material includes water collected in earlier hydrochemical monitoring programs and secondary precipitates (fracture coatings) collected on the fracture walls, as follows: (a) hydraulically pristine fracture groundwater sampled through 23 surface boreholes equipped for the retrieval of representative groundwater at controlled depths (Laxemar area), (b) fracture groundwater affected by artificial drainage collected through 80 boreholes drilled mostly along the Äspö Hard Rock Laboratory (underground research facility), (c) surface water collected in local streams, a lake and sea bay, and shallow groundwater collected in 8 regolith boreholes, and (d) 84 new specimens of fracture coatings sampled in cores from the Äspö HRL and Laxemar areas. The groundwater in each area is different, which affects Cs concentrations. The highest Cs concentrations occurred in deep-seated saline groundwater (median Äspö HRL: 4.1μgL-1; median Laxemar: 3.7μgL-1) and groundwater with marine origin (Äspö HRL: 4.2μgL-1). Overall lower, but variable, Cs concentrations were found in other types of groundwater. The similar concentrations of Cs in the saline groundwater, which had a residence time in the order of millions of years, and in the marine groundwater, which had residence times in the order of years, shows that duration of water-rock interactions is not the single and primary control of dissolved Cs in these systems. The high Cs concentrations in the saline groundwater is ascribed to long-term weathering of minerals, primarily Cs-enriched fracture coatings dominated by illite and mixed-layer clays and possibly wall rock micaceous minerals. The high Cs concentrations in the groundwater of marine origin are, in contrast, explained by relatively fast cation exchange reactions. As indicated by the field data and predicted by 1D solute transport modeling, alkali cations with low-energy hydration carried by intruding marine water are capable of (NH4 + in particular and K+ to some extent) replacing Cs+ on frayed edge (FES) sites on illite in the fracture coatings. The result is a rapid and persistent (at least in the order of decades) buildup of dissolved Cs concentrations in fractures where marine water flows downward. The identification of high Cs concentrations in young groundwater of marine origin and the predicted capacity of NH4 + to displace Cs from fracture solids are of particular relevance in the disposal of radioactive nuclear waste deep underground in crystalline rock. © 2014 Elsevier Ltd.
|
|
| 26. |
- Nitzsche, Anja, 1985-, et al.
(författare)
-
Paladin is a phosphoinositide phosphatase regulating endosomal VEGFR2 signalling and angiogenesis
- 2021
-
Ingår i: EMBO Reports. - : EMBO Press. - 1469-221X .- 1469-3178. ; 22:2
-
Tidskriftsartikel (refereegranskat)abstract
- Cell signalling governs cellular behaviour and is therefore subject to tight spatiotemporal regulation. Signalling output is modulated by specialized cell membranes and vesicles which contain unique combinations of lipids and proteins. The phosphatidylinositol 4,5-bisphosphate (PI(4,5)P-2), an important component of the plasma membrane as well as other subcellular membranes, is involved in multiple processes, including signalling. However, which enzymes control the turnover of non-plasma membrane PI(4,5)P-2, and their impact on cell signalling and function at the organismal level are unknown. Here, we identify Paladin as a vascular PI(4,5)P-2 phosphatase regulating VEGFR2 endosomal signalling and angiogenesis. Paladin is localized to endosomal and Golgi compartments and interacts with vascular endothelial growth factor receptor 2 (VEGFR2) in vitro and in vivo. Loss of Paladin results in increased internalization of VEGFR2, over-activation of extracellular regulated kinase 1/2, and hypersprouting of endothelial cells in the developing retina of mice. These findings suggest that inhibition of Paladin, or other endosomal PI(4,5)P-2 phosphatases, could be exploited to modulate VEGFR2 signalling and angiogenesis, when direct and full inhibition of the receptor is undesirable.
|
|
| 27. |
- Nyberg, Elisabeth, et al.
(författare)
-
Sakrapport Övervakning av metaller och organiska miljögifter i limnisk biota, 2013
- 2013
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The environmental contaminants examined in this report can be classified into four groups – trace metals, chlorinated compounds, brominated flame retardants and perfluoroalkyl substances. Each of these contaminants has been examined in pike, perch and Arctic char from 32 lakes geographically spread from the north to the south of Sweden. The following summary examines overall trends, spatial and temporal, for the four groups.Fat Content, Age and LengthPike and perch displayed a decreasing trend in fat content at 50 % of the sites examined. An increasing trend in fat content could be seen for Arctic char from Lake Tjulträsk. The age of the perch sampled within the programme was somewhat lower in the most southern and south eastern parts of Sweden, whereas the length of the perch was homogenous in all lakes sampled.Trace MetalsNo general temporal trend could be observed for mercury in the freshwater environment. However, in all lakes and species, except Arctic char from Abiskojaure, these concentrations are above the suggested EU-target level of 20 ng/g wet weight.Lead is generally decreasing over the study period (in time series of sufficient length), supposedly due to the elimination of lead in gasoline. In all lakes, Pb concentration is below the suggested EU-target level of 1.0 ug/g wet weight. This result has to be interpreted carefully as the recalculation between levels of lead in whole-body and liver is based on only one study.Cadmium concentrations show no consistent trends over the monitored period. It is worth noting that despite several measures taken to reduce discharges of cadmium, the most recent concentrations in Arctic char and pike are similar to concentrations measured 30 years ago in the longer time series. In a majority of the lakes, Cd concentration in perch is above the suggested EU target level of 0.16 ug/g wet weight. This result has to be interpreted carefully as the recalculation between levels of cadmium in whole-body and liver is based on only one study.Nickel concentrations showed a general increasing trend in perch. Chromium concentrations showed a general decreasing trend in all matrices during the monitoring period,but this decrease is most probably caused by the change of method for chromium analysis in 2004. The concentrations of Zinc in perch liver are consistent in all lakes monitored. The concentrations are decreasing significantly at a majority of the perch sampling sites and in pike from Lake Storvindeln.No general temporal trend were observed for copper, arsenic, silver, aluminium, tin, and bismuth concentrations in fish liver during the monitoring period.22Chlorinated CompoundsGenerally, a decreasing trend was observed for all compounds (DDT’s, PCB’s, HCH’s, HCB and PCDD/PCDF) in all species examined (with a few exceptions).The chlorinated compounds generally show a somewhat higher concentration in the southern parts of Sweden than in the north.CB-153 concentration is below the suggested target level of 1.6 ug/g lipid weight in all species and areas, while the target level for CB-118 of 0.024 ug/g lipid weight is exceeded in perch from Lake Fysingen and Lake Krankesjön. For DDE the concentration is below the suggested target level of 0.005 ug/g wet weight for all species and areas. sHCH is below the suggested target level of 0.026 ug/g wet weight for all species and areas. HCB is below the suggested target level of 0.010 ug/g wet weight for all species and areas. TCDD-eqvivalents is below the suggested target level of 3.5 pg WHO05-TEQ/g wet weight for all species and areas.Brominated Flame RetardantsNo general linear trend is observed during the whole monitoring period for the BDEs. However the concentrations of BDEs in Lake Bolmen increased from the start of the monitoring period until the late 80s to the mid 90s and appear to have decreased since then. The lower brominated flame retardants (BDE-47, BDE-99 and BDE-100) peaked earlier than the higher (BDE-153 and BDE-154).In all areas, BDE-47 is above the suggested target level of 0.0085 ng/g wet weight for all species.The concentration of HBCDD is under LOQ in a majority of the freshwater samples.PFASsPFNA, PFDA, and PFUnDA all show significantly increasing concentrations in Arctic char liver from Lake Abiskojaure. PFDA, PFUnDA, PFDoDA, and PFTrDA show increasing trends in perch liver from Lake Skärgölen. A decreasing trend in PFOS is also indicated for perch in Lake Skärgölen for the last ten years.In about 40 % of the perch lakes, PFOS concentrations in liver are above the suggested target level for PFOS inwhole fish (9.1 ng/g wet weight). This result has to be interpreted with caution since no recalculation for the results from the liver analysis has been made, especially since liver in most cases contains higher concentrations of PFASs than muscle tissue.Priority substances 2007 and 2010For four of the five priority substances - DEHP, HCBD, pentachlorobenzene, and organotin compounds – all or most values were below LOQ in the years examined. The chloroalkane SCCP did have values above LOQ, however, no consistent spatial variation was seen. The highest concentrations of SCCP (approximately 30 ng/g wet weight) were found in Lake Stor-Backsjön in Jämtland County and in Lake Fiolen in Kronobergs County. No statistical difference in concentration of SCCP between year 2007 and 2010 was found.Information about the lakes sampled within the programme can be seen in Appendix 1.
|
|
| 28. |
- Nyberg, Elisabeth, et al.
(författare)
-
Sakrapport Övervakning av metaller och organiska miljögifter i limnisk biota, 2014
- 2014
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The report summarises the monitoring activities within the National Swedish Contaminant Programme for freshwater biota. Each monitored contaminant has been examined in pike, perch and Arctic char from 32 lakes from the north to the south in Sweden.No general trend could be seen for mercury, and all samples, except Arctic char from Abiskojaure, were above the EU target level. Lead was generally decreasing. Nickel showed a general upward trend in perch. An increase, or indication of an increase, was seen for chromium during the last ten years. Zinc concentrations were decreasing in a majority of the perch samples and in pike from Lake Storvindeln. No general trend was observed for copper, arsenic, silver, aluminum, tin, bismuth, and cadmium.In general, downward trends were seen for; PCBs, HCHs, DDT, DDE and PCDD/Fs in all species (with a few exceptions). The chlorinated compounds generally show a somewhat higher concentration in the southern parts of Sweden. Most chlorinated compounds were below the suggested target levels.No general trend was seen during the monitoring period for PBDEs. Concentrations of PBDEs in Lake Bolmen increased from the 60s and peaked in the late 80s to mid-90s and have subsequently decreased. The concentration of HBCDD was under LOQ in a majority of the samples.A majority of the perfluorinated compounds showed an increase in concentration in perch, except PFOS and FOSA. Higher concentrations of perfluorinated compounds can in general be seen in the southern part of Sweden.
|
|
| 29. |
|
|
| 30. |
- Oefner, Carolin M., et al.
(författare)
-
Tolerance induction with T cell-dependent protein antigens induces regulatory sialylated IgGs
- 2012
-
Ingår i: Journal of Allergy and Clinical Immunology. - : Elsevier BV. - 1097-6825 .- 0091-6749. ; 129:6, s. 1647-1647
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Under inflammatory conditions, T cell-dependent (TD) protein antigens induce proinflammatory T-and B-cell responses. In contrast, tolerance induction by TD antigens without costimulation triggers the development of regulatory T cells. Under both conditions, IgG antibodies are generated, but whether they have different immunoregulatory functions remains elusive. Objective: It was shown recently that proinflammatory or anti-inflammatory effector functions of IgG molecules are determined by different Fc N-linked glycosylation patterns. We sought to examine the Fc glycosylation and anti-inflammatory quality of IgG molecules formed on TD tolerance induction. Methods: We administered chicken ovalbumin (OVA) with or without costimulus to mice and analyzed OVA-reactive IgG Fc glycosylation. The anti-inflammatory function of differentially glycosylated anti-OVA IgGs was further investigated in studies with dendritic cell cultures and in an in vivo model of allergic airway disease. Additionally, we analyzed the Fc glycosylation pattern of birch pollen-reactive serum IgGs after successful allergen-specific immunotherapy in patients. Results: Stimulation with TD antigens under inflammatory conditions induces plasma cells expressing low levels of alpha 2,6-sialyltransferase and producing desialylated IgGs. In contrast, plasma cells induced on tolerance induction did not downregulate alpha 2,6-sialyltransferase expression and secreted immunosuppressive sialylated IgGs that were sufficient to block antigen-specific T- and B-cell responses, dendritic cell maturation, and allergic airway inflammation. Importantly, successful specific immunotherapy in allergic patients also induced sialylated allergen-specific IgGs. Conclusions: Our data show a novel antigen-specific immunoregulatory mechanism mediated by anti-inflammatory sialylated IgGs that are formed on TD tolerance induction. These findings might help to develop novel antigen-specific therapies for the treatment of allergy and autoimmunity. (J Allergy Clin Immunol 2012;129:1647-55.)
|
|
| 31. |
- Ritscher, Amélie, et al.
(författare)
-
Zurich Statement on Future Actions on Per - and Polyfluoroalkyl Substances (PFASs)
- 2018
-
Ingår i: Journal of Environmental Health Perspectives. - 0091-6765 .- 1552-9924. ; 126:8
-
Tidskriftsartikel (refereegranskat)abstract
- Per - and polyfluoroalkyl substances (PFASs) are man-made chemicals that contain at least one perfluoroalkyl moiety, -CnF2n-. To date, over 4,000 unique PFASs have been used in technical applications and consumer products, and some of them have been detected globally in human and wildlife biomonitoring studies. Because of their extraordinary persistence, human and environmental exposure to PFASs will be a long-term source of concern. Some PFASs such as perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) have been investigated extensively and thus regulated, but for many other PFASs, knowledge about their current uses and hazards is still very limited or missing entirely. To address this problem and prepare an action plan for the assessment and management of PFASs in the coming years, a group of more than 50 international scientists and regulators held a two-day workshop in November, 2017. The group identified both the respective needs of and common goals shared by the scientific and the policy communities, made recommendations for cooperative actions, and outlined how the science-policy interface regarding PFASs can be strengthened using new approaches for assessing and managing highly persistent chemicals such as PFASs.
|
|
| 32. |
|
|
| 33. |
|
|
| 34. |
- Vierke, Lena, et al.
(författare)
-
Estimation of the Acid Dissociation Constant of Perfluoroalkyl Carboxylic Acids through an Experimental Investigation of their Water-to-Air Transport
- 2013
-
Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 47:19, s. 11032-11039
-
Tidskriftsartikel (refereegranskat)abstract
- The acid dissociation constants (pK(a)s) of perfluoroalkyl carboxylic acids (PFCAs) have been the subject of discussion in the literature; for example, values from -0.2 to 3.8 have been suggested for perfluorooctanoic acid (PFOA). The dissociated anionic conjugate bases of PFCAs have negligible air-water partition coefficients (K(AW)s) and do not volatilize from water. The neutral acids, however, have relatively high K(AW)s and volatilization from water has been demonstrated. The extent of volatilization of PFCAs in the environment will depend on the water pH and their pK(a). Knowledge of the pK(a)s of PFCAs is therefore vital for,understanding their environmental transport and fate. We investigated the water-to-air transfer of PFCAs in a novel experimental setup. We used similar to 1 mu g L-1 of PFCAs in water (above environmental background concentrations but below the concentration at which self-association occurs) at different water pH (pH 0.3 to pH 6.9) and sampled the PFCAs volatilized from water during a 2-day experiment. Our results suggest that the pK(a)s of C4-11 PFCAs are <1.6. For PFOA, we derived a pK(a) of 0.5 from fitting the experimental measurements with a volatilization model. Perfluoroalkane sulfonic acids were not volatilized, suggesting that their pK(a)s are below the investigated pH range (pK(a) <0.3).
|
|
| 35. |
- Niemi, MEK, et al.
(författare)
-
- 2021
-
swepub:Mat__t
|
|
