SwePub
Sök i SwePub databas

  Extended search

Träfflista för sökning "WFRF:(Scherstén Anders) "

Search: WFRF:(Scherstén Anders)

  • Result 1-50 of 88
Sort/group result
   
EnumerationReferenceCoverFind
1.
  • Ahlsson, Anders, 1962-, et al. (author)
  • A Swedish consensus on the surgical treatment of concomitant atrial fibrillation
  • 2012
  • In: Scandinavian Cardiovascular Journal. - London, United Kingdom : Informa Healthcare. - 1401-7431 .- 1651-2006. ; 46:4, s. 212-218
  • Research review (peer-reviewed)abstract
    • Atrial fibrillation (AF) is a common arrhythmia among patients scheduled for open heart surgery and is associated with increased morbidity and mortality. According to international guidelines, symptomatic and selected asymptomatic patients should be offered concomitant surgical AF ablation in conjunction with valvular or coronary surgery. The gold standard in AF surgery is the Cox Maze III ("cut-and-sew") procedure, with surgical incisions in both atria according to a specified pattern, in order to prevent AF reentry circuits from developing. Over 90% of patients treated with the Cox Maze III procedure are free of AF after 1 year. Recent developments in ablation technology have introduced several energy sources capable of creating nonconducting atrial wall lesions. In addition, simplified lesion patterns have been suggested, but results with these techniques have been unsatisfactory. There is a clear need for standardization in AF surgery. The Swedish Arrhythmia Surgery Group, represented by surgeons from all Swedish units for cardiothoracic surgery, has therefore reached a consensus on surgical treatment of concomitant AF. This consensus emphasizes adherence to the lesion pattern in the Cox Maze III procedure and the use of biatrial lesions in nonparoxysmal AF.
  •  
2.
  • Erlinge, D., et al. (author)
  • Bivalirudin versus Heparin Monotherapy in Myocardial Infarction
  • 2017
  • In: New England Journal of Medicine. - : Massachusetts Medical Society. - 0028-4793 .- 1533-4406. ; 377:12, s. 1132-1142
  • Journal article (peer-reviewed)abstract
    • Background The comparative efficacy of various anticoagulation strategies has not been clearly established in patients with acute myocardial infarction who are undergoing percutaneous coronary intervention (PCI) according to current practice, which includes the use of radial-artery access for PCI and administration of potent P2Y12 inhibitors without the planned use of glycoprotein IIb/IIIa inhibitors. Methods In this multicenter, randomized, registry-based, open-label clinical trial, we enrolled patients with either ST-segment elevation myocardial infarction (STEMI) or non-STEMI (NSTEMI) who were undergoing PCI and receiving treatment with a potent P2Y12 inhibitor (ticagrelor, prasugrel, or cangrelor) without the planned use of glycoprotein IIb/IIIa inhibitors. The patients were randomly assigned to receive bivalirudin or heparin during PCI, which was performed predominantly with the use of radial-artery access. The primary end point was a composite of death from any cause, myocardial infarction, or major bleeding during 180 days of follow-up. Results A total of 6006 patients (3005 with STEMI and 3001 with NSTEMI) were enrolled in the trial. At 180 days, a primary end-point event had occurred in 12.3% of the patients (369 of 3004) in the bivalirudin group and in 12.8% (383 of 3002) in the heparin group (hazard ratio, 0.96; 95% confidence interval [CI], 0.83 to 1.10; P=0.54). The results were consistent between patients with STEMI and those with NSTEMI and across other major subgroups. Myocardial infarction occurred in 2.0% of the patients in the bivalirudin group and in 2.4% in the heparin group (hazard ratio, 0.84; 95% CI, 0.60 to 1.19; P=0.33), major bleeding in 8.6% and 8.6%, respectively (hazard ratio, 1.00; 95% CI, 0.84 to 1.19; P=0.98), definite stent thrombosis in 0.4% and 0.7%, respectively (hazard ratio, 0.54; 95% CI, 0.27 to 1.10; P=0.09), and death in 2.9% and 2.8%, respectively (hazard ratio, 1.05; 95% CI, 0.78 to 1.41; P=0.76). Conclusions Among patients undergoing PCI for myocardial infarction, the rate of the composite of death from any cause, myocardial infarction, or major bleeding was not lower among those who received bivalirudin than among those who received heparin monotherapy. (Funded by the Swedish Heart-Lung Foundation and others; VALIDATE-SWEDEHEART ClinicalTrialsRegister.eu number, 2012-005260-10 ; ClinicalTrials.gov number, NCT02311231 .).
  •  
3.
  • Lindh, Anders, et al. (author)
  • A model for granite evolution based on non-equilibrium magma separation : evidence from the Gharib and Qattar fluorite-bearing granites, Eastern Desert, Egypt
  • 2019
  • In: International Journal of Earth Sciences. - : Springer Science and Business Media LLC. - 1437-3254 .- 1437-3262. ; 108:4, s. 1201-1232
  • Journal article (peer-reviewed)abstract
    • We present 77 new granite whole-rock analyses from the Qattar and Gharib areas, Eastern Desert, Egypt. Both areas include a “normal” granite and either a hypersolvus (Gharib) or an almost plagioclase-free granite (Qattar) enriched in fluorite. According to earlier results, F influences element distribution in granitic melts forming complexes with specific elements as Nb, Ta, Ga, Hf, Th, Zn, Sn, whereas F excludes Ba and Sr. We use principal component analyses to split the granite into chemical groups allowing an unbiased study of the inter-group element distribution. This adds the heavy REEs and Y to the earlier lists of elements with an affinity for F. The light REEs show a decreasing affinity with decreasing atomic mass; fluorine separates Sm from Nd, whereas Zr follows La. Opposite to some, but in accordance with other earlier results, the ratio Nb/Ta is higher in the fluorite-enriched than in the other granite. Weak tetrad effects are present. Zircon in the hypersolvus granite is high in common lead. We suggest F to be instrumental for separating Pb 2+ from Pb 4+ . Two hypotheses may explain the occurrence of the two contrasting granites: they have either different sources, or they are co-magmatic, but the magma was split into two discrete types. We apply the second hypothesis as our working hypothesis. The liquidus has a gentler slope with pressure than the diapir requiring crystallisation to be most important in the lower part of the magma chamber. Our hypothesis suggests that globules of magma, enriched in volatile components, form during crystallisation due to slow diffusion rates in the crystallizing magma. Elements accompanying F are distributed into this magma batch, which has a lowered density and viscosity than the rest of the magma due to its increased contents of volatile components. A mushroom-formed diapir rises, forming the hypersolvus (or almost plagioclase-free) granite. Due to an edge effect, it is concentrated close to the wall of the magma chamber. The size and form of the outcropping granite depend on the intersection of the diapir with the erosion surface. Fluorine only makes it possible to follow the process. The model may be generalised to explain the diversification of non-F enriched granite, since the buoyancy of a magma batch several thousand m 3 in size has a much larger impact on the system than the small negative buoyancy of crystals or small crystal aggregates. A-type granite classified merely from its trace element content may form from separated F-enriched magma batches. This may be the reason for their high frequency in the Eastern Desert.
  •  
4.
  • Plan, Anders, et al. (author)
  • Exceptional preservation of reidite in the Rochechouart impact structure, France: New insights into shock deformation and phase transition of zircon
  • 2021
  • In: Meteoritics and Planetary Science. - : Wiley. - 1086-9379 .- 1945-5100. ; 56:10, s. 1795-1828
  • Journal article (peer-reviewed)abstract
    • Reidite, the high-pressure zircon (ZrSiO4) polymorph, is a diagnostic indicator of impact events. Natural records of reidite are, however, scarce, occurring mainly as micrometer-sized lamellae, granules, and dendrites. Here, we present a unique sequence of shocked zircon grains found within a clast from the Chassenon suevitic breccia (shock stageIII) from the ~200 Ma, 20–50 km wide Rochechouart impact structure in France. Our study comprises detailed characterization with scanning electron microscopy coupled with electron backscatter diffraction with the goal of investigating the stability and response of ZrSiO4 under extreme P–T conditions. The shocked zircon grains have preserved various amounts of reidite ranging from 4% up to complete conversion. The grains contain various variants of reidite, including the common habits: lamellae and granular reidite. In addition, three novel variants have been identified: blade, wedge, and massive domains. Several of these crosscut and offset each other, revealing that reidite can form at multiple stages during an impact event. Our data provide evidence that reidite can be preserved in impactites to a much greater extent than previously documented. We have further characterized reversion products of reidite in the form of fully recrystallized granular zircon grains and minute domains of granular zircon in reidite-bearing grains that occur in close relationship to reidite. Neoblasts in these grains have a distinct crystallography that is the result of systematic inheritance of reidite. We interpret that the fully granular grains have formed from prolonged exposure of temperatures in excess of 1200 °C. Reidite-bearing grains with granular domains might signify swift quenching from temperatures close to 1200 °C. Grains subjected to these specific conditions therefore underwent partial zircon-to-reidite reversion, instead of full grain recrystallization. Based on our ZrSiO4 microstructural constraints, we decipher the grains evolution at specific P–T conditions related to different impact stages, offering further understanding of the behavior of ZrSiO4 during shock.
  •  
5.
  • Albåge, Anders, et al. (author)
  • Long-Term Follow-Up of Cardiac Rhythm in 320 Patients After the Cox-Maze III Procedure for Atrial Fibrillation
  • 2016
  • In: Annals of Thoracic Surgery. - : Elsevier BV. - 0003-4975 .- 1552-6259. ; 101:4, s. 1443-1449
  • Journal article (peer-reviewed)abstract
    • Background. The Cox-maze III (CM-III) procedure is the gold standard for surgical treatment of atrial fibrillation (AF). Excellent short-term results have been reported, but long-term outcomes are lesser known. The aim was to evaluate current cardiac rhythm in a nationwide cohort of CM-III patients with very long follow-up.Methods. Perioperative characteristics were retrospectively analyzed in 536 "cut-and-sew" CM-III patients operated on from 1994 to 2009 in 4 centers. Of these, 54 patients had died and 20 were unavailable at follow-up. The remaining 462 patients received a survey concerning arrhythmia symptoms, rhythm, and medication; of these, 320 patients (69%), comprising 252 men, with a mean age of 67 years (range, 47 to 87 years), and 83% with stand-alone CM-III, returned a current 12-lead electrocardiogram. Long-term monitoring was evaluated in 40 sinus rhythm patients. Postoperative stroke/transient ischemic attack was evaluated by register analysis.Results. Mean follow-up was 111 44 months (range, 36-223 months). Electrocardiogram analysis showed sinus rhythm in 219 of 320 patients (68%), and regular supraventricular rhythm (sinus, nodal, or atrial pacing) in 262 (82%), with 75% off class I/III antiarrhythmic medication. This group had lower arrhythmia symptom scores and medication use. Rhythm outcome did not differ by gender, age, type of AF, or stand-alone vs concomitant operation. Patients with more than 10 years of follow-up had a lower rate of regular supraventricular rhythm (69% vs 91%, p = 0.02). Long-term monitoring showed freedom from AF/atrial flutter in 38 of 40 patients (95%). The incidence of stroke/transient ischemic attack was 0.37% per year (11 patients).Conclusions. In a single-moment electrocardiogram evaluation 9 years after the cut-and-sew CM-III, 82% of patients were in sinus rhythm or other regular supraventricular rhythm. These findings support a long-lasting positive effect of the CM-III procedure, which is relevant when evaluating current nonpharmacologic therapies for AF. (C) 2016 by The Society of Thoracic Surgeons
  •  
6.
  • Albåge, Anders, et al. (author)
  • Long-Term Risk of Ischemic Stroke After the Cox-Maze III Procedure for Atrial Fibrillation
  • 2017
  • In: Annals of Thoracic Surgery. - : Elsevier BV. - 0003-4975 .- 1552-6259. ; 104:2, s. 523-529
  • Journal article (peer-reviewed)abstract
    • Background The long-term risk of stroke after surgical treatment of atrial fibrillation is not well known. We performed an observational cohort study with long follow-up after the “cut-and-sew” Cox-maze III procedure (CM-III), including left atrial appendage excision. The aim was to analyze the incidence of stroke/transient ischemic attack (TIA) and the association to preoperative CHA2DS2-VASc (age in years, sex, congestive heart failure history, hypertension history, stroke/TIA, thromboembolism history, vascular disease history, diabetes mellitus) score. Methods Preoperative and perioperative data were collected in 526 CM-III patients operated in four centers 1994 to 2009, 412 men, mean age of 57.1 ± 8.3 years. The incidence of any stroke/TIA was identified through analyses of the Swedish National Patient and Cause-of-Death Registers and from review of individual patient records. The cumulative incidence of stroke/TIA and association with CHA2DS2-VASc score was estimated using methods accounting for the competing risk of death. Results Mean follow-up was 10.1 years. There were 29 patients with any stroke/TIA, including 6 with intracerebral bleedings (2 fatal) and 4 with perioperative strokes (0.76%). The remaining 13 ischemic strokes and six TIAs occurred at a mean of 7.1 ± 4.0 years postoperatively, with an incidence of 0.36% per year (19 events per 5,231 patient-years). In all CHA2DS2-VASc groups, observed ischemic stroke/TIA rate was lower than predicted. A higher risk of ischemic stroke/TIA was seen in patients with CHA2DS2-VASc score 2 or greater compared with score 0 or 1 (hazards ratio 2.15, 95% confidence interval: 0.87 to 5.32) but no difference by sex or stand-alone versus concomitant operation. No patient had ischemic stroke as cause of death. Conclusions This multicenter study showed a low incidence of perioperative and long-term postoperative ischemic stroke/TIA after CM-III. Although general risk of ischemic stroke/TIA was reduced, patients with CHA2DS2-VASc score 2 or greater had a higher risk compared with score 0 or 1. Complete left atrial appendage excision may be an important reason for the low ischemic stroke rate.
  •  
7.
  • Albåge, Anders, et al. (author)
  • The Berglin apical stitch : a simple technique to straighten things out in atrial fibrillation surgery
  • 2014
  • In: Interactive Cardiovascular and Thoracic Surgery. - : Oxford University Press (OUP). - 1569-9293 .- 1569-9285. ; 19:4, s. 685-686
  • Journal article (peer-reviewed)abstract
    • In the Cox-Maze IV procedure, or in endocardial left atrial ablation, correct positioning of the surgical ablation probe within the left atrium might be difficult due to bulging or folds in the posterior left atrial wall. The Berglin apical stitch is a simple trick of the trade to create a smooth surface in the posterior left atrium that facilitates performing a safe transmural lesion and, consequently, may increase antiarrhythmic efficiency.
  •  
8.
  •  
9.
  • Alwmark, Carl, et al. (author)
  • An Early Ordovician 40Ar-39Ar age for the ∼50 km Carswell impact structure, Canada
  • 2017
  • In: Geological Society of America Bulletin. - 0016-7606. ; 129:11/12, s. 1442-1449
  • Journal article (peer-reviewed)abstract
    • The formation age of the large (∼50 km) Carswell impact structure, Canada, has been a matter of debate ever since its discovery five decades ago, with proposed ages ranging from Mesoproterozoic to Early Cretaceous. Here, we present new 40Ar-39Ar data for aliquots of euhedral adularia, separated from vesicles in an impact melt rock from the central uplift of the structure. The analyses of the adularia yielded a statistically robust Early Ordovician crystallization age of 481.5 ± 0.8 Ma (2σ, mean square of weighted deviates = 1.06, P = 0.30). The most plausible explanation for the formation of vesicle-filling adularia is through low-temperature mineral precipitation during residual hydrothermal circulation that followed the impact, as no other known major intrusive, extrusive, or thermal events have occurred in the Carswell region in the Phanerozoic. The new age of the Carswell impact structure overlaps within uncertainty with the most precise Ar-Ar ages proposed for the L-chondrite parent body breakup event, but not with the age of the stratigraphic sequence from which the meteorites and micrometeorites from this event were recovered. Thus, either the Carswell impact represents a separate, unrelated impact event, or the dynamic evolution of the L-chondrite parent body breakup is more complicated than presently understood, and Carswell represents one of the earliest and largest known impacts of this event on Earth.
  •  
10.
  • Bech-Hanssen, Odd, 1956, et al. (author)
  • Pressure reflection in the pulmonary circulation in patients with severe mitral regurgitation indicates adverse postoperative outcome.
  • 2013
  • In: European Journal Cardio-Thoracic Surgery. - : Oxford University Press (OUP). - 1010-7940 .- 1873-734X. ; 44:6, s. 1037-1044
  • Journal article (peer-reviewed)abstract
    • OBJECTIVES: Severe pulmonary hypertension (PH) is a known risk factor in valvular surgery. In the present study, we hypothesized that the assessment of pressure reflection (PR) in the pulmonary circulation, indicating increased pulmonary vascular resistance, might improve the identification of patients with increased morbidity and mortality following surgery for severe mitral regurgitation. METHODS: A total of 103 patients without atrial fibrillation were divided into three groups: Group 1 (n = 48), patients without PR; Group 2 (n = 36), patients with PR and pulmonary artery systolic pressure (PASP) ≤60 mmHg and Group 3 (n = 19), patients with PR and PASP >60 mmHg. Three variables related to PR were selected: the acceleration time in the right ventricular outflow tract (RVOT), the interval between peak velocity in the RVOT and peak tricuspid regurgitant jet velocity and the right ventricular pressure increase after peak RVOT velocity. RESULTS: There were no differences between groups in age, ejection fraction, need for coronary bypass grafting or creatinine. Patients with PR (Groups 2 and 3) had more use of vasoactive drugs (overall P < 0.0001, Group 1 vs Group 2 P = 0.018). The proportion of patients with >24 h in the intensive care unit was 27% in Group 1, 54% in Group 2 and 84% in Group 3 (overall P < 0.0001, Group 1 vs Group 2 P = 0.006). The in-hospital mortality in patients without PR (n = 49) was 0% compared with 10.9% in patients with PR (P = 0.029). CONCLUSIONS: Echocardiography assessment of PR in the pulmonary circulation and severe PH may identify patients with adverse outcome following mitral surgery.
  •  
11.
  • Bjärnborg, Karolina, et al. (author)
  • Geochronology and geochemical evidence for a magmatic arc setting for the Ni-Cu mineralised 1.79Ga Kleva gabbro-diorite intrusive complex, southeast Sweden
  • 2015
  • In: GFF. - : Informa UK Limited. - 2000-0863 .- 1103-5897. ; 137:2, s. 83-101
  • Journal article (peer-reviewed)abstract
    • Magmatic Ni-Cu sulphide deposits are commonly associated with mafic rocks within the marginal areas of Archean or Proterozoic cratons. The Kleva Ni-Cu sulphide deposit in southeast Sweden is hosted by gabbro-diorite rocks and is sandwiched between two Palaeoproterozoic magmatic arcs: the Transscandinavian Igneous Belt (TIB) and the Oskarshamn-Jonkoping Belt (OJB). Major and trace element data corroborate an arc origin for the Kleva intrusive complex. The variety of rocks and geochemical signatures suggest that it formed from several magmatic pulses. Despite the occurrence of supracrustal xenoliths, there is a lack of trace element evidence for significant assimilation. Mafic intrusions are abundant in southeast Sweden and are generally inferred to be synchronous with the TIB. Of these, Kleva is the only known Ni-Cu deposit, and it is unclear if it is associated with the OJB or TIB. Here, we present zircon and baddeleyite U-Pb dates of 1788 +/- 4Ma, 1788 +/- 5Ma and 1792 +/- 3Ma. We interpret a 1790Ma date to be the best estimate of the crystallisation age of the Kleva intrusive complex, indicating that the emplacement of mafic magma is coeval with the voluminous arc-related TIB magmatism in the area.
  •  
12.
  • Bjärnborg, Karolina, et al. (author)
  • The age of the Kleva intrusion, southeast Sweden
  • 2013
  • In: Mineral deposit research for a high-tech world : Proceedings of the 12th Biennial SGA Meeting, 12-15 August 2013, Uppsala, Sweden. - 9789174032079 ; , s. 1647-1649
  • Conference paper (peer-reviewed)abstract
    • The Kleva nickel-copper mineralization is situated within a gabbro-diorite intrusion on the border between the late Svecofennian rocks of the Oskarshamn-Jonkoping belt and rocks of the slightly younger Transscandinavian Igneous Belt (TIB). The sulphides present in the mafic intrusion are pyrrhotite, chalcopyrite, pentlandite and pyrite, occurring as massive mineralization, disseminations and thin, predominantly chalcopyrite-bearing veins. Age determinations of the gabbro-diorite were conducted to determine the age of the mineralization and its regional context. U-Pb analyses of baddeleyite (TIMS) and zircon (SIMS) from the gabbro-diorite and related rocks indicate an age of c. 1.79 Ga for the Kleva intrusion, broadly coeval with the TIB-rocks in the area, but younger than the late Svecofennian rocks. Further studies will help to constrain whether the sulphide mineralization was modified during later alteration, regional tectonism and metamorphism.
  •  
13.
  • Braathen, Bjørn, et al. (author)
  • One single dose of histidine-tryptophan-ketoglutarate solution gives equally good myocardial protection in elective mitral valve surgery as repetitive cold blood cardioplegia: A prospective randomized study.
  • 2011
  • In: The Journal of thoracic and cardiovascular surgery. - : Elsevier BV. - 1097-685X .- 0022-5223. ; 141:4, s. 995-1001
  • Journal article (peer-reviewed)abstract
    • OBJECTIVES: Histidine-tryptophan-ketoglutarate (HTK-Custodiol) cardioplegic solution is administered as one single dose for more than 2 hours of ischemia. No prospective randomized clinical study has compared the effects of HTK and cold blood cardioplegia on myocardial damage in elective mitral valve surgery. Thus, the main aim of the present study was to examine whether one single dose of cold antegrade HTK gives as good myocardial protection as repetitive antegrade cold blood cardioplegia in mitral valve surgery. METHODS: Eighty consecutive patients undergoing elective isolated mitral valve surgery for mitral regurgitation, with or without ablation for atrial fibrillation, were included in the study and randomized to HTK or blood cardioplegia. Markers of myocardial injury (troponin-T and creatine kinase MB) were analyzed at baseline and 7 hours, 1 day, 2 days, and 3 days after surgery. RESULTS: No significant difference in creatine kinase MB and troponin-T between HTK and blood cardioplegia groups was found at any time point. There was a significant correlation between ischemic time and markers of myocardial injury in the HTK group only and significantly more spontaneous ventricular fibrillation after release of crossclamping in the HTK group. CONCLUSIONS: One single dose of antegrade cold HTK cardioplegic solution in elective mitral valve surgery protects the myocardium equally good as repetitive antegrade cold blood cardioplegia.
  •  
14.
  •  
15.
  • Calner, Mikael, et al. (author)
  • Vandring runt Hunnebo klåvor
  • 2017
  • In: Geologiskt Forum. - 1104-4721. ; 95, s. 22-24
  • Journal article (pop. science, debate, etc.)
  •  
16.
  • Caton, Summer A., et al. (author)
  • Evolution of the sources of TTG and associated rocks during the Archean from in-situ 87Sr/86Sr isotope analysis of apatite by LA-MC-ICPMS
  • 2022
  • In: Lithos. - : Elsevier BV. - 0024-4937 .- 1872-6143. ; 428-429
  • Journal article (peer-reviewed)abstract
    • Radiogenic isotopes provide an important means towards elucidating Archean crustal evolution. The global Hf and Nd isotope record of Archean crustal fragments has been instrumental to unveiling the history of ancient crustal growth and differentiation. The Rb-Sr system could provide valuable complementary constraints in this regard, as this system is particularly sensitive to magmatic fractionation processes, and the chemical and isotopic evolution of magma sources. Application of this system has so far been complicated, however, by its susceptibility to isotope re-equilibration or alteration of the Rb/Sr parent-daughter ratio. In-situ Sr isotope analysis of primary igneous minerals with very low Rb/Sr, such as apatite, provides a new means to determine the initial 87Sr/86Sr (87Sr/86Sri) values for igneous rocks directly. In this study, we apply in-situ Sr isotope analysis of apatite by LA-MC-ICPMS to tonalite-trondhjemite-granodiorite (TTG) rocks and end-member sanukitoids from Archean cratons worldwide. The 87Sr/86Sri values of sanukitoids are relatively radiogenic, supporting the model in which such rocks are formed by flux melting of a mantle strongly enriched by metasomatism, possibly by slab-derived fluids. The 87Sr/86Sri values for TTGs formed between 3.72 and 3.45 Ga are generally radiogenic, indicating aged amphibolite sources. The 87Sr/86Sri values of younger TTGs are systematically lower and were derived from mafic sources that had an average age of ≤0.2 Gyr. This evolution matches with observations from Hf isotopes for TTGs of similar age and indicates a systematic change in the nature or efficiency of TTG crust formation during the Paleoarchean. In-situ Sr isotope analysis of apatite provides a useful method to uncover the Sr record of the early continental crust, and enables constraints on local source evolution and the general two-step evolutionary process of Archean crust formation.
  •  
17.
  • Cornell, David H., 1948, et al. (author)
  • A new chronostratigraphic paradigm for the age and tectonic history of the Mesoproterozoic Bushmanland Ore District.
  • 2009
  • In: Economic Geology. ; 104, s. 385-404
  • Journal article (peer-reviewed)abstract
    • The four giant stratiform Cu-Pb-Zn-Ag base metal deposits of the Bushmanland Ore District have long been regarded as Paleoproterozoic sedimentary-exhalative deposits formed in a continental basin at about 1650 Ma and overlying the Achab Gneiss, an approximately 2.0 Ga basement complex, with no known Archean crustal history. The supracrustal sequence was thought to include the Hoogoor 'pink' metavolcanic gneiss at the base and the ore-bearing metaquartzites to be unconformably overlain by the 1650 Ma Koeris Formation. All the supracrustals were regarded as predating the 1200 to 1000 Ma Namaqua-Natal orogenic cycle. In this work we present ion probe and laser ablation zircon dating of xenocrystic, magmatic, detrital and metamorphic zircon which leads to fundamental changes in our understanding of the age and tectonic history of the Bushmanland Ore District. The Bushmanland base metal deposits are not older than 1650 Ma as entrenched in the literature, but younger than the 1285 ± 14 Ma detrital zircons found within the ore horizon at Gamsberg. The ore is probably older than the 1198 ±10 and 1154 ± 18 Ma detrital zircons found in the unconformably overlying Koeris Formation, and most likely older than the 1130 ± 35 Ma Koeris Formation metabasalts. The existence of an Archean crustal component in the Bushmanland Ore District has now been established by detrital zircon ages and by Sm-Nd model ages. However no outcrops of Archean rocks have yet been found. The Bushmanland Group metasediments were derived largely from 1850 to 2100 Ma Paleoproterozoic rocks, which probably reflects their provenance in the Richtersveld Subprovince to the north. However they also contain Mesoproterozoic detrital zircon which constrains their minimum age. The Bushmanland Ore District metasediments conform to the same chronostratigraphic and tectonostratigraphic pattern as recently established at Bitterfontein to the southwest. An older group represented by the Bushmanland Group and including the sedimentary-exhalative Cu-Pb-Zn-Ag ores, formed before, but within 80 Ma of, the main collision event at 1200 Ma. A younger group, represented by the Koeris Formation, formed after the main collision at about 1130 Ma. The older group should thus have experienced an early collision-related D1 folding event and metamorphism, whereas the younger group should show only D2-D3 and M2-M3 metamorphism, between 1130 and 1000 Ma. This prediction should be tested against more structural observations. The 1204 ± 11 Ma Aroams Gneiss is now recognised as the oldest known granitoid in the Bushmanland Ore District, in agreement with other recently published ion probe data. However it probably does not represent basement to the older metasediments. The Achab Gneiss, previously thought to be about 2000 Ma old and the polydeformed basement, is dated by our published 1166 ± 13 and 1163 ± 11 Ma concordia ages for magmatic emplacement. The Aroams Gneiss is confirmed to belong to the 1200 Ma syn-collisional Little Namaqualand Suite documented in the Okiep Copper District to the west. The 30 Ma younger Achab and Hoogoor Gneisses may be grouped in the Aggeneys Suite. Microbeam zircon dating has established a new chronostratigraphic paradigm for the geological history of the Bushmanland Ore District, however many issues related to ore formation and the deformation history remain to be resolved.
  •  
18.
  •  
19.
  • Cornell, David H., 1948, et al. (author)
  • Evidence from Dwyka tillite cobbles of Archean basement beneath the Kalahari sands of southern Africa
  • 2011
  • In: Lithos. - 0024-4937. ; 125, s. 482-502
  • Journal article (peer-reviewed)abstract
    • We have found a new source of information about what lies beneath the Kalahari sands. The Kheis and Rehoboth Provinces of southern Africa were thought to be underlain by either an ~1800 Ma orogenic belt, or a northern branch of the ~1200 Ma Namaqua–Natal Province. Glacial diamictites of the Permocarboniferous Dwyka Group exposed at Rietfontein west of the Kalahari sands carry cobbles plucked from the bedrock by the ice sheet which covered the Gondwana supercontinent about 300 Ma ago. Despite altered mineralogy, the cobbles are not severely altered geochemically. Their normative mineral compositions give classifications as trondhjemites and granites, supported by rare earth element diagrams. Microbeam U–Pb zircon dating of the granitic cobbles shows that they contain no evidence of crustal growth or orogeny at either 1800 or 1200 Ma. Rather they testify to the presence of 2500 to 2900 Ma Archaean trondhjemitic and granitic crust beneath the Kalahari, with a lesser ~2050 Ma granite component. The pebble assemblages from the diamictites we sampled lack the diagnostic banded iron formation (BIF), stromatolitic limestone and other supracrustal pebbles which characterise diamictites derived from the Kaapvaal Craton, thus we envisage shorter transport distances and derivation from the region now beneath the Kalahari sands. Three of the Archaean granite cobbles have unusual less-than-mantle zircon oxygen isotope values around +3 (δ18O VSMOW), which may reflect interaction of their source with high-temperature, originally meteoric water before melting to produce the granites. The mafic cobbles described in a companion paper are much younger and are related to intrusions of the 1.1 Ga Umkondo Large Igneous Province, probably located on the Kalahari Line or Rehoboth Province. Five trondhjemitic granites from the westernmost outcrops of the Kaapvaal Craton were dated, the oldest being 3061±9 Ma and four others between 2882±7 Ma and 2854±7 Ma, reflecting the cratonisation of the Kimberley Terrane. Four of the Archaean Dwyka cobbles we dated are younger than the 2.7 Ga Kaapvaal cover sequence and are thus too young to be derived from the craton. All the Dwyka cobbles described here are most likely derived from either the Rehoboth Province or the Kalahari Line with origins from the Kheis Province, Kaapvaal Craton, or further afield considered unlikely. We envisage the Rehoboth Province to consist of an Archaean core supplemented by Palaeoproterozoic granitoids, which was joined to the Kaapvaal Craton at an early stage of crustal development and played an important role during later tectonic events. This has important implications not only for the tectonic framework and assembly of Southern Africa, but also for exploration for diamonds and other ore deposits.
  •  
20.
  •  
21.
  • Cornell, David H., 1948, et al. (author)
  • Zircon dating reveals an Archaean crust beneath the Kalahari sand.
  • 2008
  • In: Annual Meeting Mineralogical Network, Natural History Museum, University of Oslo, June 2008. ; abstracts
  • Conference paper (other academic/artistic)abstract
    • Continents are subdivided into structural provinces based on the age of the last orogeny or major magmatic event which imprinted the structural fabric on the bedrock. These first-order subdivisions are important in understanding how the continents were assembled. The continuity and boundaries of provinces such as the Namaqua-Natal Province in Southern Africa have been established, however adjoining Kheis province which lies almost entirely under the Tertiary to Recent Kalahari sands, has thus far defied attempts to understand its age and geological history. A foreland thrust complex developed in 1.92 Ga redbeds at Olifantshoek (Fig. 1a) was postulated by Cornell et al. 1998. However the much younger 1.2 Ga to 1.1 Ga Sinclair Sequence volcanic and plutonic rocks exposed in the same area suggest that the Kheis Province could have experienced an Andean-type orogeny at ~1.2 Ga. Thus Moen (1999) suggested that much of the Kheis Province was coeval with and belonged to the ~1.2 Ga Namaqua-Natal Province. At Rietfontein on the eastern margin of the Kheis, tillites of the Permian Dwyka Group, were found to contain abundant cobble-sized clasts of crystalline bedrock. Bearing in mind the generally westward transport directions for the Dwyka Ice sheet (Fig. 1a), these exposures were investigated to see if they contained information about what lies under the Kalahari. These granotoid cobbles are badly weathered, but we succeeded in dating them using an ion probe and laser ablation ICPMS, by the U-Pb method. The data is largely discordant, reflecting ancient lead loss at the time of glaciation. Nevertheless we find compelling evidence that Archean and 2.0 Ga (Bushveld Complex age) granitic crust exists beneath the Kalahari. We also failed to find any evidence for the existence of younger granitic crust or high-grade metamorphic terranes. The published concepts of the Kheis Province as either a 1900 - 1750 Ma collisional orogen, or an extension of the 1200 Ma Namaqua Province find no support in our data. The possibility of Archean and Bushveld-aged rocks occuring as basement beneath the Kalahari has important implications for diamond, base and precious metal prospecting in the western Kalahari in South Africa, Botswana and Namibia. These possibilities should be tested by drilling with geophysical control, the last such campaign having been completed in Botswana in 1984.
  •  
22.
  • Dahlman, S., et al. (author)
  • Expanding the donor pool: lung transplantation with donors 55 years and older
  • 2006
  • In: Transplant Proc. - 0041-1345. ; 38:8, s. 2691-3
  • Journal article (peer-reviewed)abstract
    • The scarcity of donor organs is one of the major limitations to lung transplantation. This has led to a progressive expansion of criteria for donor selection in lung transplantation. This study evaluated the outcome of recipients of lungs from donors >/=55 years. We performed a retrospective analysis of 212 consecutive lung transplantations. Recipients were divided into two groups, those receiving lungs from donors >/=55 years (older donor group) and those receiving lungs from donors <55 years (younger donor group). Recipient baseline characteristics, time in the intensive care unit (ICU), early mortality, and long-term survival (Kaplan-Meier) were compared between the groups. Forty-one donors (19%) were >/=55 years. Mean recipient age in the older donor group was higher than in the younger donor group (52 +/- 8 vs. 47 +/- 12 years; P = .015). Indication for transplantation did not differ between the groups. ICU stay was comparable between the two groups (6 +/- 12 vs. 7 +/- 11 days; P = .64). Actual 30-day mortality (10.8% vs. 6.4%; P = .32), 1-year mortality (17.1 vs. 19.6%; P = .50), and cumulative long-term survival (65% and 62% at 5 years, P = 1.00) did not differ between the older and younger donor group. This study indicated that transplantation of lungs from selected donors aged >/=55 years did not impair short-or long-term results. The use of lungs from elderly donors may help to increase the number of donor organs for lung transplantation.
  •  
23.
  • Dyhr, Charlotte T., et al. (author)
  • Subduction controls on Miocene back-arc lavas from Sierra de Huantraico and La Matancilla and new Ar-40/Ar-39 dating from the Mendoza Region, Argentina
  • 2013
  • In: Lithos. - : Elsevier BV. - 0024-4937. ; 179, s. 67-83
  • Journal article (peer-reviewed)abstract
    • Back-arc volcanism in the western Argentinian provinces of Mendoza and Neuquen has been widespread from the Miocene to historic times. We present a detailed investigation of profiles through two of the major Miocene volcanic areas of the region, the neighboring Huantraico and La Matancilla plateaus, including new Ar-40/Ar-39 age results of major and trace elements as well as Nd, Sr and Pb isotopic data. Four million years of eruptions from 24.4 +/- 0.3 Ma (2 sigma) of alkali olivine basalts with OIB-type incompatible trace element enrichments at La Matancilla (similar to 36.50 degrees S) provide evidence for the presence of back-arc mantle devoid of subduction-related components. In contrast, the lower Huantraico lavas (similar to 37.30 degrees S) require an atypical back-arc mantle, almost devoid of arc-like components (e.g. low La/Ta = 15-18 and Ba/La = 12-18), but with a more depleted isotopic signature (e.g. Sr-87/Sr-86, 0.7033-0.7037) than observed elsewhere in the Andean back-arc. The Lower to Upper Series development in the Huantraico sequence represents a gradual change from basaltic to trachyandesitic back-arc lavas with a weak but temporally increasing arc geochemical signature (e.g. La/Ta = 15-21; Ba/La = 12-45), which is accompanied by Sr, Nd and Pb isotopic compositions approaching present day values of the Andes arc. The compositional change is accompanied by a gradually decreasing role for garnet in the mantle source, a decreasing degree of melting, but also simultaneously increasing influence from subducted fluids, probably as the slab geometry changes through time. The volcanism at Huantraico ceased when a flat slab was established around 15 Ma. (C) 2013 Elsevier B.V. All fights reserved.
  •  
24.
  • Erlinge, David, et al. (author)
  • Bivalirudin versus heparin monotherapy in non-ST-segment elevation myocardial infarction
  • 2019
  • In: European Heart Journal. - : Sage Publications. - 2048-8726 .- 2048-8734. ; 8:6, s. 492-501
  • Journal article (peer-reviewed)abstract
    • BACKGROUND: The optimal anti-coagulation strategy for patients with non-ST-elevation myocardial infarction treated with percutaneous coronary intervention is unclear in contemporary clinical practice of radial access and potent P2Y12-inhibitors. The aim of this study was to investigate whether bivalirudin was superior to heparin monotherapy in patients with non-ST-elevation myocardial infarction without routine glycoprotein IIb/IIIa inhibitor use.METHODS: In a large pre-specified subgroup of the multicentre, prospective, randomised, registry-based, open-label clinical VALIDATE-SWEDEHEART trial we randomised patients with non-ST-elevation myocardial infarction undergoing percutaneous coronary intervention, treated with ticagrelor or prasugrel, to bivalirudin or heparin monotherapy with no planned use of glycoprotein IIb/IIIa inhibitors during percutaneous coronary intervention. The primary endpoint was the rate of a composite of all-cause death, myocardial infarction or major bleeding within 180 days.RESULTS: A total of 3001 patients with non-ST-elevation myocardial infarction, were enrolled. The primary endpoint occurred in 12.1% (182 of 1503) and 12.5% (187 of 1498) of patients in the bivalirudin and heparin groups, respectively (hazard ratio of bivalirudin compared to heparin treatment 0.96, 95% confidence interval 0.78-1.18, p=0.69). The results were consistent in all major subgroups. All-cause death occurred in 2.0% versus 1.7% (hazard ratio 1.15, 0.68-1.94, p=0.61), myocardial infarction in 2.3% versus 2.5% (hazard ratio 0.91, 0.58-1.45, p=0.70), major bleeding in 8.9% versus 9.1% (hazard ratio 0.97, 0.77-1.24, p=0.82) and definite stent thrombosis in 0.3% versus 0.2% (hazard ratio 1.33, 0.30-5.93, p=0.82).CONCLUSION: Bivalirudin as compared to heparin during percutaneous coronary intervention for non-ST-elevation myocardial infarction did not reduce the composite of all-cause death, myocardial infarction or major bleeding in non-ST-elevation myocardial infarction patients receiving current recommended treatments with modern P2Y12-inhibitors and predominantly radial access.
  •  
25.
  •  
26.
  •  
27.
  • Grenholm, Mikael, et al. (author)
  • A hypothesis for Proterozoic-Phanerozoic supercontinent cyclicity, with implications for mantle convection, plate tectonics and Earth system evolution
  • 2015
  • In: Tectonophysics. - : Elsevier BV. - 0040-1951. ; 662:S1, s. 434-453
  • Journal article (peer-reviewed)abstract
    • We present a conceptual model for supercontinent cycles in the Proterozoic-Phanerozoic Eons. It is based on the repetitive behavior of C and Sr isotopes in marine carbonates and U–Pb ages and εHf of detrital zircons seen during the Neoproterozoic-Paleozoic and Paleoproterozoic Eras, respectively. These records are considered to reflect secular changes in global tectonics, and it is hypothesized that the repetitive pattern is caused by the same type of changes in global tectonics. The fundamental premise of this paper is that such repetitive changes should also be recorded in orogenic belts worldwide. This carries the implication that Neoproterozoic-Paleozoic orogenic belts should have Paleoproterozoic equivalents. It is proposed that this is the case for the East African, Uralides and Ouachita–Alleghanian orogens, which have Paleoproterozoic analogs in the West African–Amazon, Laurentian and East European cratons, respectively. The Neoproterozoic-Paleozoic orogenic belts are not isolated features but occur in a specific global context, which correspond to the relatively well-constrained Neoproterozoic break-up of Rodinia, and the subsequent Late Paleozoic assembly of Pangea. The existence of Paleoproterozoic equivalents to Neoproterozoic-Paleozoic orogens requires that the same cycle defined the Paleoproterozoic. We therefore hypothesize that there were Paleoproterozoic supercontinents equivalent to Rodinia and Pangea, and that Proterozoic-Phanerozoic supercontinents are comprised of two basic types of configurations, equivalent to Rodinia (R-type) and Pangea (P-type). The Paleoproterozoic equivalent of Rodinia is likely the first supercontinent to have formed, and Proterozoic-Phanerozoic supercontinent cycles are therefore defined by R- to R-type cycles, each lasting approximately 1.5 Gyr. We use this cyclic pattern as a framework to develop a conceptual model that predicts the configuration and cycles of Proterozoic-Phanerozoic supercontinents, and their relation to mantle convection and Earth system evolution.
  •  
28.
  • Hafström, Lars-Olof, 1936, et al. (author)
  • Isolated hyperthermic liver perfusion with chemotherapy for liver malignancy.
  • 1994
  • In: Surgical oncology. - 0960-7404. ; 3:2, s. 103-8
  • Journal article (peer-reviewed)abstract
    • In an open study of unresectable liver tumours, isolated regional perfusion with hyperthermia and cytotoxic drugs has been tested in 29 patients. Four patients had primary hepatocellular cancer, 10 patients had metastases from malignant melanoma, remaining from breast cancer, colorectal cancer, midgut carcinoids and miscellaneous primaries. At laparotomy the proper hepatic artery and portal vein were canulated and connected to a pump oxygenator. The inferior vena cava was canulated with a triple lumen catheter (Perfufix) allowing for porto-caval shunting, drainage of lower body and renal veins to the heart and separate drainage of liver veins to the pump oxygenator. Liver perfusion was performed with a mean flow of 900 ml per min. Melphalan and cis-platinum 0.5 mg/kg body-weight were added to the perfusate for 1 h after liver temperature reached 40 degrees C. Four patients died within 30 days of perfusion due to multiple organ failure. These patients had more than 50% of liver volume occupied by cancer. All surviving patients developed reversible hepato- and renal toxicity. Partial tumour regression was registered in 20% of the patients. Five patients have survived more than three years. Hyperthermic liver perfusion is feasible but in patients with massive liver tumour, there is a significant risk of developing multiple organ failure.
  •  
29.
  • Hamnegård, Carl-Hugo, 1954, et al. (author)
  • Effect of lung volume reduction surgery for emphysema on diaphragm function
  • 2006
  • In: Respir Physiol Neurobiol.. ; 150:2-3
  • Journal article (peer-reviewed)abstract
    • Preoperative prediction of a successful outcome following lung volume reduction surgery (LVRS) for emphysema is imperfect. One mechanism could be improvement in respiratory muscle function yet controversy exists regarding the magnitude and mechanism of such an improvement. Therefore, we measured diaphragm strength in 18 patients before and after LVRS. Mean (S.D.) FRC fell from 6.53 to 5.40l (p=0.0001). Mean sniff transdiaphragmatic pressure increased from 76 to 87cmH(2)O (14%, p<0.03) and mean twitch transdiaphragmatic pressure (Tw Pdi) increased by 2.5cmH(2)O at 3 months (12%, p=0.03). There was a highly significant increase in twitch esophageal pressure (Tw Pes) (60%, p<0.0001), which was maintained at 12 months (46% increase, p=0.0004). No change was observed in quadriceps twitch tension in nine subjects in whom it was measured. After LVRS the ratio Tw Pes:Tw Pdi increased from 0.24 to 0.37 at 3 months (p=0.0003) and 0.36 at 12 months (p=008). Low values of Sn Pdi, Sn Pes, Tw Pes and a high RV/TLC ratio were the preoperative variables most predictive of improvement in shuttle walking distance. We conclude that LVRS improves diaphragm function primarily by alteration of lung volume. Patients with poor diaphragm function and high RV/TLC ratio preoperatively are most likely to benefit from the procedure.
  •  
30.
  • Herrmann, Maria, et al. (author)
  • The effect of low-temperature annealing on discordance of U–Pb zircon ages
  • 2021
  • In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1
  • Journal article (peer-reviewed)abstract
    • Discordant U–Pb data of zircon are commonly attributed to Pb loss from domains with variable degree of radiation damage that resulted from α-decay of U and Th, which often complicates the correct age interpretation of the sample. Here we present U–Pb zircon data from 23 samples of ca. 1.7–1.9 Ga granitoid rocks in and around the Siljan impact structure in central Sweden. Our results show that zircon from rocks within the structure that form an uplifted central plateau lost significantly less radiogenic Pb compared to zircon grains in rocks outside the plateau. We hypothesize that zircon in rocks within the central plateau remained crystalline through continuous annealing of crystal structure damages induced from decay of U and Th until uplifted to the surface by the impact event ca. 380 Ma ago. In contrast, zircon grains distal to the impact have accumulated radiation damage at shallow and cool conditions since at least 1.26 Ga, making them vulnerable to fluid-induced Pb-loss. Our data are consistent with studies on alpha recoil and fission tracks, showing that annealing in zircon occurs at temperatures as low as 200–250 °C. Zircon grains from these samples are texturally simple, i.e., neither xenocrysts nor metamorphic overgrowths have been observed. Therefore, the lower intercepts obtained from regression of variably discordant zircon data are more likely recording the age of fluid-assisted Pb-loss from radiation-damaged zircon at shallow levels rather than linked to regional magmatic or tectonic events.
  •  
31.
  • Hoffmann, J. Elis, et al. (author)
  • The geodynamic evolution of Mesoarchean anorthosite complexes inferred from the Naajat Kuuat Complex, southern West Greenland
  • 2012
  • In: Precambrian Research. - : Elsevier BV. - 0301-9268 .- 1872-7433. ; 196, s. 149-170
  • Journal article (peer-reviewed)abstract
    • Layered anorthosite complexes are typical components of Archean crustal domains. However, the geodynamic settings in which they were emplaced are still discussed as geological relationships are often ambiguous. Here we report major, trace element and high-precision high-field-strength-element (HFSE) data for the recently discovered well preserved Naajat Kuuat Anorthosite Complex from the inner Ameralik fjord region, southern West Greenland. The dataset is complemented by the first combined Hf-Nd isotope analyses for Archean layered anorthosite complexes and U-Pb zircon geochronology. The data contribute to the small database on Archean layered anorthosite complexes and are used to unravel the origin of these complexes and the tectonic regime involved. Fractional crystallisation of olivine, pyroxene, plagioclase and possibly amphibole controls major and trace element variations in the layered intrusion. There are two groups of amphibolites: (1) a group with primitive mantle normalized trace element patterns are similar to those of MORB-like basalts and (2) typical island-arc tholeiites (IAT), apparently indicating an island-arc setting. Lu-Hf regression lines yield an age of 2985 +/- 59 Ma (MSWD 4) within the error of the Sm-Nd regression age of 2929 110 Ma (MSWD 17). The initial epsilon Hf(2985) for the Naajat Kuuat rocks range from +1.6 to +5.8 and the initial epsilon Nd(2985) range from +0.4 to +3.9, either indicating variably depleted mantle sources or variable degrees of crustal contamination. In contrast to most mafic assemblages, ratios of Nb/Ta are highly variable (7.85 to 18.6), reflecting fractionation and accumulation of amphibole, ilmenite and pyroxene. The MORB-like parental liquids have the highest Nb/Ta of ca. 18, consistent with a mantle source overprinted by melt-like components from subducting oceanic crust with high Nb/Ta. The accumulation of plagioclase forming the anorthosites and the primary fractionation of amphibole as well as the occurrence of high-Al basalts within the Naajat Kuuat complex argue for hydrous parental liquids in support of an island-arc related setting. Zircon U-Pb geochronology from the anorthosite and adjacent tonalites reveal major tonalite intrusion into the complex at ca. 2802 Ma and a second regional event at ca. 2710 Ma, in accord with crustal heating due to micro-continent amalgamation and crustal thickening. Altogether, the geochemical data can be interpreted with a geodynamic model, where anorthosite-complex associated rocks intrude into tectonically thickened island-arc crust. Crustal thickening is possibly triggered by island-arc accretion, leading to the emplacement of TTG bodies that further thickened the crustal pile. Further collision and amalgamation with other proto-crustal assemblages might have led to enhanced crustal magmatism and granulite facies metamorphism.
  •  
32.
  • Hollis, J. A., et al. (author)
  • Detrital zircon U-Pb-Hf and O isotope character of the Cahill Formation and Nourlangie Schist, Pine Creek Orogen: Implications for the tectonic correlation and evolution of the North Australian Craton
  • 2014
  • In: Precambrian Research. - : Elsevier BV. - 0301-9268. ; 246, s. 35-53
  • Journal article (peer-reviewed)abstract
    • Detrital zircon age and Hf isotope patterns for the Cahill Formation and Nourlangie Schist are distinctly different from other Paleoproterozoic successions in the North Australian Craton. The Cahill Formation and Nourlangie Schist comprise the bulk of the Paleoproterozoic strata in the Nimbuwah Domain, the easternmost part of the Pine Creek Orogen on the northern margin of the North Australian Craton. They comprise micaceous and quartzofeldspathic schist, carbonaceous schist, calc-silicate rock, amphibolite and quartzite, deformed and metamorphosed during emplacement of the granitic to dioritic Nimbuwah Complex at 1867-1857 Ma. The Cahill Formation hosts several world-class uranium deposits including Ranger, Jabiluka and Nabarlek. U-Pb SHRIMP and LA-SF-ICPMS detrital zircon spectra for four samples of the Cahill Formation and six samples of the Nourlangie Schist show a similar broad spectrum of ages mainly in the range 3300-1900 Ma. A ubiquitous dominant peak at 2530-2470 Ma matches the age of underlying Neoarchean basement, but is distinct in its dominantly mantle-like Hf and O zircon isotopic character, which shows closer similarity with possible source rocks from the Gawler Craton or alternatively from the Dharwar Craton. Common smaller age peaks occur at 2180 Ma, 2080 Ma and 2020 Ma. The first two have no known magmatic age correlatives in the North Australian Craton. Zircons of the 2020 Ma peak have distinctively unradiogenic Hf and elevated delta O-18, at variance with local rocks of this age but similar to detrital zircon of the same age from the Gawler Craton. In contrast to younger Proterozoic sedimentary successions within the Pine Creek Orogen, which contain ubiquitous ca. 1870 Ma detritus, the detrital spectra for the Cahill Formation and Nourlangie Schist contain almost no ca. 1870 Ma detritus. A maximum deposition age of ca. 1866 Ma indicates deposition within error of intrusion of the Nimbuwah Complex. We propose that the Cahill Formation and Nourlangie Schist were deposited at a plate margin immediately prior to convergent tectonism. This resulted in their burial, deformation and amphibolite facies metamorphism during orogenesis associated with the Nimbuwah Event. These findings have implications for understanding the Paleoproterozoic evolution of the Pine Creek Orogen within the context of northern Australia. Crown Copyright (C) 2014 Published by Elsevier B.V. All rights reserved.
  •  
33.
  • Kalsbeek, Feiko, et al. (author)
  • Enigmatic 1146 ± 4 Ma old granite in the southeastern rim of the West African craton, now part of the Dahomeyan orogenic belt in Ghana
  • 2020
  • In: Journal of African Earth Sciences. - : Elsevier BV. - 1464-343X. ; 167
  • Journal article (peer-reviewed)abstract
    • A unique exposure of a strongly deformed late Mesoproterozoic augen-granite (U–Pb zircon age 1146 ± 4 Ma) was detected within rocks on the eastern rim of the West African Craton. These rocks, together with their sedimentary cover, were reworked during the Neoproterozoic Pan-African Dahomeyan orogeny, and are now incorporated in the Dahomeyan orogenic belt of southeast Ghana. To the authors’ knowledge no similar ages have been reported from elsewhere in the West African Craton or in the Pan-African orogenic belts farther north or their continuation in northeastern Brazil. Most other granitoid rocks in the Dahomeyan belt are of Palaeoproterozoic age. Two of them were dated for this study and yielded Concordia ages of 2067 ± 15 Ma and 2119 ± 13 Ma. Lower intercepts around 600 Ma in Wetherill discordia diagrams demonstrate disturbance of the U–Pb systems during the Pan-African orogenic cycle. Chemical data indicate that the Palaeoproterozoic granitoid rocks are arc-type granites (sensu lato), while the Mesoproterozoic augen-granite has the chemical composition of an alkaline within-plate granite. Chemical, whole rock Sm–Nd and zircon Lu–Hf data suggest that the magma that yielded the augen-granite was formed by melting within a mafic Palaeoproterozoic source at moderate crustal depth. The occurrence of a Mesoproterozoic granite in the (now) eastern margin of the West African Craton is evidence of a previously unknown igneous event within this terrain.
  •  
34.
  • Kemp, Tony, et al. (author)
  • Concurrent Pb-Hf isotope analysis of zircon by laser ablation multi-collector ICP-MS, with implications for the crustal evolution of Greenland and the Himalayas
  • 2009
  • In: Chemical Geology. - : Elsevier BV. - 0009-2541. ; 261:3-4, s. 244-260
  • Journal article (peer-reviewed)abstract
    • Abstract in UndeterminedThe in situ Lu-Hf isotope analysis of zircon by laser ablation has emerged as a high-calibre tool for tackling magmatic and crustal evolution. The strength of the approach lies with the ability to target specific zircon growth domains identified by imaging, and thus to unravel polyphase crystallisation histories. However, due to the volume of material being sampled during analysis there remains the possibility of ablation-induced mixing between Hf from domains of different age. Inaccurate Hf isotope ratios and spurious geological interpretations could result. One approach to this problem involves dating the same volume of material analysed for Hf isotopes by concurrently measuring (207)Pb/(206)Pb ratios during ablation [Woodhead,J.D., Hergt,J.M.. Shelley, M., Eggins, S., Kemp, R. 2004. Zircon Hf-isotope analysis with an excimer laser, depth profiling, ablation of complex geometries, and concomitant age estimation. Chemical Geology 209,121-135.]. This paper explores the viability of this dual analysis by investigating complex zircons from three different geological contexts, detrital zircons in sedimentary rocks, inherited zircons in granites, and zircons in metamorphosed Eo-Archaean TTG gneisses from Greenland. The implications of the Greenland data for Archaean crustal evolution are discussed in the light of published solution zircon Hf isotope datasets from these gneisses. A case study of detrital zircons from modern river sands in the Himalayas highlights the potential of the technique for providing a rapid, cost-effective picture of crustal evolution that should complement regional bulk rock studies.
  •  
35.
  • Keulen, Nynke, et al. (author)
  • Meso- and Neoarchaean geological history of the Bjornesund and Ravns Storo Supracrustal Belts, southern West Greenland: Settings for gold enrichment and corundum formation
  • 2014
  • In: Precambrian Research. - : Elsevier BV. - 0301-9268. ; 254, s. 36-58
  • Journal article (peer-reviewed)abstract
    • To understand the Mesa- and Neoarchaean geological history of the Bjornesund region, southern West Greenland (ca. 62-63 degrees N), we have undertaken an integrated study combining field observations with U-Pb zircon geochronology by LA-ICP-MS, metamorphic petrology, and microstructural analyses. The Bjornesund region links the southern part of the Fiskenaesset anorthosite complex to the well-preserved metavolcanic rocks of the Ravn Story Supracrustal Belt and the Bjornesund Supracrustal Belt, so the development of this region is of key interest to unravelling the Archaean geology of the entire region. In this study, we couple the observed phases of gold-enrichment and corundum formation to the geological history. The leucogabbroic rocks of the Bjornesund region, which are part of the Fiskenaesset complex, intruded at ca. 2.95 Ga into the tholeiitic and calc-alkaline metavolcanic rocks of the two studied belts. Following isoclinal folding, the rocks were intruded by diorite (2.92 Ga) and granodiorite (2.91 and 2.88 Ga), which are now texturally orthogneisses. The area was affected by three major phases of folding; F1 (undated), F2 at 2.85-2.83 Ga, and F3 at 2.71-2.70 Ga. The former deformation event is associated with the gold-enrichment in alteration zones in shear folds in metavolcanic amphibolite near the contact with the orthogneiss. Intrusion of granitic sheets during the F3 deformation triggered the formation of corundum, which is locally of gem quality, at the contact between leucogabbroic and ultramafic rocks. Peak metamorphic conditions were calculated as 580-630 degrees C and 6-4 kbar at 2.85-2.83 Ga. Later retrogression in the southern part of the area at ca. 500-450 degrees C and 4.5-3 kbar, and extensional fault reactivation overprinted some of the older structures. (C) 2014 Elsevier B.V. All rights reserved.
  •  
36.
  •  
37.
  •  
38.
  •  
39.
  • Kiviniemi, T., et al. (author)
  • A randomized prospective multicenter trial for stroke prevention by prophylactic surgical closure of the left atrial appendage in patients undergoing bioprosthetic aortic valve surgery––LAA-CLOSURE trial protocol
  • 2021
  • In: American Heart Journal. - : Elsevier BV. - 0002-8703 .- 1097-6744. ; 237, s. 127-134
  • Journal article (peer-reviewed)abstract
    • Patients undergoing surgical aortic valve replacement (SAVR) are at high risk for atrial fibrillation (AF) and stroke after surgery. There is an unmet clinical need to improve stroke prevention in this patient population. The LAA-CLOSURE trial aims to assess the efficacy and safety of prophylactic surgical closure of the left atrial appendage for stroke and cardiovascular death prevention in patients undergoing bioprosthetic SAVR. This randomized, open-label, prospective multicenter trial will enroll 1,040 patients at 13 European sites. The primary endpoint is a composite of cardiovascular mortality, stroke and systemic embolism at 5 years. Secondary endpoints include cardiovascular mortality, stroke, systemic embolism, bleed fulfilling academic research consortium (BARC) criteria, hospitalization for decompensated heart failure and health economic evaluation. Sample size is based on 30% risk reduction in time to event analysis of primary endpoint. Prespecified reports include 30-day safety analysis focusing on AF occurrence and short-term outcomes and interim analyses at 1 and 3 years for primary and secondary outcomes. Additionally, substudies will be performed on the completeness of the closure using transesophageal echocardiography/cardiac computed tomography and long-term ECG recording at one year after the operation. © 2021 The Author(s)
  •  
40.
  • Lewerentz, Alexander, et al. (author)
  • Baddeleyite formation in zircon by Ca-bearing fluids in silica-saturated systems in nature and experiment : resetting of the U-Pb geochronometer
  • 2019
  • In: Contributions to Mineralogy and Petrology. - : Springer Science and Business Media LLC. - 0010-7999 .- 1432-0967. ; 174:8
  • Journal article (peer-reviewed)abstract
    • Intergrowths of baddeleyite have been found in zircon grain interiors from amphibolite- and granulite-facies felsic rocks from southwest Greenland. The zircon grains are either close to or in direct contact with quartz. A series of experiments has been conducted using natural, unaltered zircon grains +/- SiO2 in H2O-CaCl2, and H2O-Ca(OH)(2) solutions with varying molar proportions of Ca to Si at 900 degrees C; 1000MPa and 600 degrees C; 400MPa for 4-50days. Experimental results indicate that baddeleyite formed in the reacted zircon if the molar amount of Ca was close to or greater than Si in the system. The baddeleyite primarily takes the form of bead-like trails along the reaction front between the altered and unaltered zircon. Uranium, Th, and Y+REE were detected in both the newly formed baddeleyite and in the altered zircon, while Pb was effectively absent in both phases. Formation of baddeleyite from zircon in the silica-saturated rocks only appears to be possible when Ca saturates the system, such that the Si is tied up as CaSiO3 lowering the silica activity to <1. This highly localized (mu m to nm scale) effect in natural quartz-bearing rocks, where baddeleyite forms in the interiors of zircon grains in contact with quartz, implies that metastability in natural rock-forming systems can occur on a very small scale. Non-incorporation of Pb in the newly formed baddeleyite, or in areas of the zircon altered by fluids, implies that either could be used to date the metasomatic event responsible for their formation.
  •  
41.
  •  
42.
  • Maulana, Adi, et al. (author)
  • Origin and geodynamic setting of Late Cenozoic granitoids in Sulawesi, Indonesia
  • 2016
  • In: Journal of Asian Earth Sciences. - : Elsevier BV. - 1367-9120. ; 124, s. 102-125
  • Journal article (peer-reviewed)abstract
    • Late Cenozoic granitoids are widespread in a 1600km long belt forming the Western and Northern Sulawesi tectono-magmatic provinces. They can be divided into three rock series: shoshonitic (HK), high-K felsic calc-alkaline (CAK), and normal calc-alkaline to tholeiitic (CA-TH). Representative samples collected from eleven plutons, which were subjected to petrography, major element, trace element, Sr, Nd, Pb isotope and whole-rock δ18O analyses, are all I-type and metaluminous to weakly peraluminous. The occurrence of the two K-rich series is restricted to Western Sulawesi, where they formed in an extensional, post-subduction tectonic setting with astenospheric upwelling providing thermal perturbation and adiabatic decompression. Two parental magma sources are proposed: enriched mantle or lower crustal equivalent for HK magmas, and Triassic igneous rocks in a Gondwana-derived fragment thrust beneath the cental and northern parts of Western Sulawesi for CAK magmas. The latter interpretation is based on striking similarities in radiogenic isotope and trace element signatures. CA-TH granitoids are found mostly in Northern Sulawesi. Partial melting of lower-middle crust amphibolites in an active subduction environment is the proposed origin of these rocks. Fractional crystallization and crustal contamination have played a significant role in magma petrogenesis, particularly in the case of the HK and CAK series. Contamination by organic carbon-bearing sedimentary rocks of the HK and CAK granitoids in the central part of Western Sulawesi is suggested by their ilmenite-series (reduced) character. The CAK granitoids further to the north and CA-TH granitoids in Northern Sulawesi are typical magnetite-series (oxidized). This may explain differences in mineralization styles in the two regions.
  •  
43.
  • Mohammad, Moman A., et al. (author)
  • Incidence and outcome of myocardial infarction treated with percutaneous coronary intervention during COVID-19 pandemic
  • 2020
  • In: Heart. - : BMJ Publishing Group Ltd. - 1355-6037 .- 1468-201X. ; 106:23, s. 1812-1818
  • Journal article (peer-reviewed)abstract
    • OBJECTIVE: Most reports on the declining incidence of myocardial infarction (MI) during the COVID-19 have either been anecdotal, survey results or geographically limited to areas with lockdowns. We examined the incidence of MI during the COVID-19 pandemic in Sweden, which has remained an open society with a different public health approach fighting COVID-19.METHODS: We assessed the incidence rate (IR) as well as the incidence rate ratios (IRRs) of all MI referred for coronary angiography in Sweden using the nationwide Swedish Coronary Angiography and Angioplasty Registry (SCAAR), during the COVID-19 pandemic in Sweden (1 March 2020-7 May 2020) in relation to the same days 2015-2019.RESULTS: A total of 2443 MIs were referred for coronary angiography during the COVID-19 pandemic resulting in an IR 36 MIs/day (204 MIs/100 000 per year) compared with 15 213 MIs during the reference period with an IR of 45 MIs/day (254 MIs/100 000 per year) resulting in IRR of 0.80, 95% CI (0.74 to 0.86), p<0.001. Results were consistent in all investigated patient subgroups, indicating no change in patient category seeking cardiac care. Kaplan-Meier event rates for 7-day case fatality were 439 (2.3%) compared with 37 (2.9%) (HR: 0.81, 95% CI (0.58 to 1.13), p=0.21). Time to percutaneous coronary intervention (PCI) was shorter during the pandemic and PCI was equally performed, indicating no change in quality of care during the pandemic.CONCLUSION: The COVID-19 pandemic has significantly reduced the incidence of MI referred for invasive treatment strategy. No differences in overall short-term case fatality or quality of care indicators were observed.
  •  
44.
  • Myint, Aung Zaw, et al. (author)
  • Stable isotope and geochronological study of the Mawchi Sn-W deposit, Myanmar : Implications for timing of mineralization and ore genesis
  • 2018
  • In: Ore Geology Reviews. - : Elsevier BV. - 0169-1368. ; 95, s. 663-679
  • Journal article (peer-reviewed)abstract
    • Myanmar is endowed with abundant Sn-W mineralization, pre-eminent amongst which is the world-class Mawchi deposit. In the Mawchi area, N-S trending vertical or steeply dipping quartz veins are hosted by both Eocene granite and Carboniferous to Early Permian metasediments. Three stages of ore formation are recognized; (i) tourmaline-cassiterite stage (ii) main ore stage and (iii) sulfide stage. Tourmaline, cassiterite and pyrite-I are early-formed minerals and are representative of the first stage. Their deposition continued together with wolframite, scheelite, molybdenite, arsenopyrite, pyrite-II, fluorite and danalite, which form the second stage. This was followed by the successive deposition of sulfides such as chalcopyrite, sphalerite, galena and Pb-Bi sulfides. A 40Ar/39Ar magmatic biotite plateau age of 41.50 ± 0.16 Ma (MSWD = 2.5) is determined for the Mawchi biotite granite which we interpret as the time the granite cooled through the biotite blocking temperature, and is consistent with a previously reported LA-ICP-MS U-Pb zircon concordia age of 42.72 ± 0.94 Ma (MSWD = 2). A molybdenite Re-Os model age of 42.4 ± 1.2 Ma indicates that Sn-W mineralization was synchronous with late Eocene granitic magmatism. Our 40Ar/39Ar hydrothermal muscovite plateau ages from the tourmaline granite (40.14 ± 0.14 Ma; MSWD = 1.48) and quartz vein selvages (40.80 ± 0.12 Ma; MSWD = 0.47) define the timing of hydrothermal alteration and simultaneous veining that accompanied the late stage of ore forming at Mawchi. Fluid inclusion microthermometry from cassiterite, scheelite, quartz, and fluorite reveals that ore fluids in the cassiterite-tourmaline stage and main ore stage are characterized by moderate homogenization temperatures (Th = 260–345 °C) and salinities (4.5–15.7 wt% NaCl equiv), while the sulfide stage is characterized by lower temperatures (Th = 175–260 °C) and moderate to low salinity (2.5–13 wt% NaCl equiv). The mean δ34S of all sulfides is 2.9 ± 2.9‰ which is suggestive that the overall system is dominated by magmatic sulfur. The similarity of δ34S values in galena and Pb-Bi sulfides (−1.3 to 2.7‰) suggest that sulfur, and inference the Pb and Bi were transported by a common fluid, probably of magmatic origin. The calculated δ18OH2O of the hydrothermal fluid associated with cassiterite and tourmaline is 7.3–8.4‰. Scheelite and quartz deposition is characterized by lighter δ18OH2O values (2.1–4.9‰) indicating that the ore fluid might be mixed with another source of water, perhaps, meteoric. Hydrogen isotopic compositions (δD = −51 to −121‰) again indicate that origin of the ore fluid is magmatic, but δD (∼−120‰) is low enough to support the δ18OH2O data that suggests, in part, a meteoric water component to the hydrothermal fluids at Mawchi.
  •  
45.
  •  
46.
  • Naeraa, Tomas, et al. (author)
  • A lower crustal mafic source for the ca. 2550 Ma Qorqut Granite Complex in southern West Greenland
  • 2014
  • In: Lithos. - : Elsevier BV. - 0024-4937 .- 1872-6143. ; 192, s. 291-304
  • Journal article (peer-reviewed)abstract
    • The late Neoarchaean Qorqut Granite Complex is the youngest large igneous intrusion in the Nuuk region in southern West Greenland, where basement is primarily of Eoarchaean and Mesoarchaean age with a tonalite-trondhjemite-granodiorite (TTG) composition. The Qorqut granite is generally undeformed and it intruded during a prolonged period, starting at ca. 2730 Ma, characterised by crustal reworking, possibly related to syn- or post accretion tectonics or continental collision. We present major and trace element whole rock chemistry and combined U/Pb, Hf and O isotope data from zircon. We obtained a mean zircon U/Pb age of 2547 +/- 4 Ma (MSWD = 0.63). Initial sHf values range from - 12 to -18 requiring a long residence time and a rather homogeneous source. Sample averaged zircon delta O-18 values range from 6.1 +/- 0.2%. to 6.5 +/- 0.3/0.7%o best interpreted with a source region of mainly unweathered mantle derived igneous rocks. Compared to the regional TTG basement, the QGC is characterised by low CaO and Na2O and high K2O, LREE and Rb contents, and a stronger fractionated REE pattern with a negative Eu anomaly. We show that the homogeneous Hf isotope signature of the granite together with its low epsilon value and its pristine oxygen isotope composition are best explained with an Eoarchaean mafic source with a Lu-176/Hf-176 around 0.015-0.019. Trace element modelling confirms that a mafic source in REE and with an eclogitic residue and with plagioclase as a fractionating phase would generate appropriate melt compositions. Modelling requires residual rutile in the source which constrain the pressures to > ca. 13-18 kbar. Zirconium saturation temperatures suggest magma temperatures in the range 750-850 degrees C. The obtained P-T conditions suggest a lower crustal source region in a thickened crustal unit consistent with a post or late continental collisional setting. (C) 2014 Elsevier B.V. All rights reserved.
  •  
47.
  • Naeraa, Tomas, et al. (author)
  • Hafnium isotope evidence for a transition in the dynamics of continental growth 3.2Gyr ago
  • 2012
  • In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 485:7400, s. 627-627
  • Journal article (peer-reviewed)abstract
    • Earth's lithosphere probably experienced an evolution towards the modern plate tectonic regime, owing to secular changes in mantle temperature(1,2). Radiogenic isotope variations are interpreted as evidence for the declining rates of continental crustal growth over time(3-5), with some estimates suggesting that over 70% of the present continental crustal reservoir was extracted by the end of the Archaean eon(3,5). Patterns of crustal growth and reworking in rocks younger than three billion years (Gyr) are thought to reflect the assembly and break-up of supercontinents by Wilson cycle processes and mark an important change in lithosphere dynamics(6). In southern West Greenland numerous studies have, however, argued for subduction settings and crust growth by arc accretion back to 3.8 Gyr ago(7-9), suggesting that modern-day tectonic regimes operated during the formation of the earliest crustal rock record. Here we report in situ uranium-lead, hafnium and oxygen isotope data from zircons of basement rocks in southern West Greenland across the critical time period during which modern-like tectonic regimes could have initiated. Our data show pronounced differences in the hafnium isotope-time patterns across this interval, requiring changes in the characteristics of the magmatic protolith. The observations suggest that 3.9-3.5-Gyr-old rocks differentiated from a >3.9-Gyr-old source reservoir with a chondritic to slightly depleted hafnium isotope composition. In contrast, rocks formed after 3.2 Gyr ago register the first additions of juvenile depleted material (that is, new mantle-derived crust) since 3.9 Gyr ago, and are characterized by striking shifts in hafnium isotope ratios similar to those shown by Phanerozoic subduction-related orogens(10-12). These data suggest a transitional period 3.5-3.2 Gyr ago from an ancient (3.9-3.5 Gyr old) crustal evolutionary regime unlike that of modern plate tectonics to a geodynamic setting after 3.2 Gyr ago that involved juvenile crust generation by plate tectonic processes.
  •  
48.
  • Næraa, Tomas, et al. (author)
  • The ca. 2785–2805 Ma high temperature ilivertalik intrusive complex of southern west Greenland
  • 2018
  • In: Geosciences (Switzerland). - : MDPI AG. - 2076-3263. ; 8:9
  • Journal article (peer-reviewed)abstract
    • Ferroan granitoid intrusions are rare in the Archaean rock record, but have played a large role in the evolution of the Proterozoic crust, particular in relation to anorthosite-mangerite-charnockite-granite suites. Here we discuss the petrogenesis of the ca. 2785–2805 Ma ferroan Ilivertalik Intrusive Complex, which has many geochemical similarities to Proterozoic iron rich granitoids. We present major and trace element whole rock chemistry and combined in-situ zircon U-Pb, Hf and O isotope data. The intrusive complex divides into: (i) minor tabular units of mainly diorite-tonalite compositions, which are typically situated along contacts to the host basement and (ii) interior larger, bodies of mainly granite-granodiorite composition. Geochemically these two unites display continuous to semi-continuous trends in Haker-diagrams. Whole rock REE enrichment display increases from Yb to La, from 10–25 to 80–100 times chondrite, respectively. The diorite-tonalite samples are generally more enriched in REE compared to the granite-granodiorite samples. The complex has hafnium isotope compositions from around +1.5 to −2.5 epsilon units and δ18O compositions in the range of 6.3 to 6.6‰. The complex is interpreted to be derived from partial melting in a crustal source region during anomalously high crustal temperatures.
  •  
49.
  • Nilsson, Mimmi K. M., et al. (author)
  • Precise U-Pb baddeleyite ages of mafic dykes and intrusions in southern West Greenland and implications for a possible reconstruction with the Superior craton
  • 2010
  • In: Precambrian Research. - : Elsevier BV. - 0301-9268. ; 183:3, s. 399-415
  • Journal article (peer-reviewed)abstract
    • The Archaean block of southern Greenland constitutes the core of the North Atlantic craton (NAC) and is host to a large number of Precambrian mafic intrusions and dyke swarms, many of which are regionally extensive but poorly dated. For southern West Greenland, we present a U-Pb zircon age of 2990 +/- 13 Ma for the Amikoq mafic-ultramafic layered intrusion (Fiskefjord area) and four baddeleyite U-Pb ages of Precambrian dolerite dykes. Specifically, a dyke located SE of Ameralik Fjord is dated at 2499 +/- 2 Ma, similar to a previously reported Ar-40/Ar-39 age of a dyke in the Kangamiut area. For these and related intrusions of ca. 2.5 Ga age in southern West Greenland, we propose the name Kilaarsarfik dykes. Three WNW-trending dykes of the MD3 swarm yield ages of 2050 +/- 2 Ma, 2041 +/- 3 Ma and 2029 +/- 3 Ma. A similar U-Pb baddeleyite age of 2045 +/- 2 Ma is also presented for a SE-trending dolerite (Iglusuataliksuak dyke) in the Nain Province, the rifted western block of the NAC in Labrador. We speculate that the MD3 dykes and age-equivalent NNE-trending Kangamiut dykes of southern West Greenland, together with the Iglusuataliksuak dyke (after closure of the Labrador Sea) represent components of a single, areally extensive, radiating swarm that signaled the arrival of a mantle plume centred on what is presently the western margin of the North Atlantic craton. Comparison of the magmatic 'barcodes' from the Nain and Greenland portions of the North Atlantic craton with the established record from the north-eastern Superior craton shows matches at 2500 Ma, 2214 Ma, 2050-2030 Ma and 1960-1950 Ma. We use these new age constraints, together with orientations of the dyke swarms, to offer a preliminary reconstruction of the North Atlantic craton near the north-eastern margin of the Superior craton during the latest Archaean and early Palaeoproterozoic, possibly with the Core Zone craton of eastern Canada intervening. (C) 2010 Elsevier B.V. All rights reserved.
  •  
50.
  • Perrotta, Sossio, 1975, et al. (author)
  • Surgical treatment for isolated mitral valve endocarditis: a 16-year single-centre experience
  • 2018
  • In: European Journal of Cardio-Thoracic Surgery. - : Oxford University Press (OUP). - 1010-7940 .- 1873-734X. ; 53:3, s. 576-581
  • Journal article (peer-reviewed)abstract
    • Despite progress in management, mitral valve endocarditis (MVE) is still a life-threatening disease. We report our experience in surgical treatment of infective isolated MVE. A total of 140 operations in 128 patients for MVE performed between January 2000 and December 2015 were included in a retrospective study. There were 109 (78%) operations for native and 31 (22%) operations for prosthetic valve endocarditis. Preoperative and postoperative characteristics and mortality of patients were registered. Cox regression identified factors associated with mortality. Mean follow-up period was 68 months (range 1-168 months) and 100% complete. There were 13 deaths within 30 days after the 140 operations (9%). Severe perioperative complications occurred in 59 (42%) operations. Overall cumulative survival was 73% +/- 4 at 5 years and 62 +/- 5% at 10 years after the first operation. Age, diabetes, EuroSCORE II and perivalvular abscess were independent predictors for long-term mortality. Valve repair was performed in 76 (54%) operations and replacement in 64 (46%) operations. Thirty-day mortality for repair was 1%, and 5-year and 10-year cumulative survival was 86 +/- 4% and 77 +/- 6%, respectively. In the replacement group the 30-day mortality was 19% and cumulative survival at 5 years and 10 years was 55 +/- 7% and 41 +/- 8%, respectively. Postoperative complications occurred in 21% and 67%, respectively, after operations for repair and replacement. Ten (8%) patients had 12 reoperations for recurrent endocarditis. MVE requiring surgical treatment is a challenging disease with high hospital mortality after valve replacement. Mitral valve repair can be performed in suitable endocarditis patients with excellent results. Age, diabetes and EuroSCORE were independently associated with mortality in a multivariable model.
  •  
Skapa referenser, mejla, bekava och länka
  • Result 1-50 of 88
Type of publication
journal article (78)
conference paper (6)
reports (2)
doctoral thesis (1)
research review (1)
Type of content
peer-reviewed (79)
other academic/artistic (7)
pop. science, debate, etc. (2)
Author/Editor
Scherstén, Anders (66)
Næraa, Tomas (13)
Scherstén, Henrik, 1 ... (10)
Jeppsson, Anders, 19 ... (8)
Petersson, Andreas (8)
Kokfelt, Thomas F. (8)
show more...
Szilas, Kristoffer (7)
Cornell, David H., 1 ... (6)
SÖderlund, Ulf (6)
Keulen, Nynke (6)
Scherstén, Henrik (5)
Frei, Robert (5)
Gerdes, Axel (5)
van Hinsberg, Vincen ... (5)
Whitehouse, Martin J ... (4)
Fröbert, Ole, 1964- (4)
James, Stefan, 1964- (4)
Jidéus, Lena (4)
Albåge, Anders (4)
Windley, Brian F. (4)
Page, Laurence (4)
Ulvenstam, Anders (4)
Hoffmann, J. Elis (4)
Pettersson, A (3)
Erlinge, David (3)
Alexanderson, Helena (3)
Kimblad, Per Ola (3)
Koul, Sasha (3)
Jensen, Jens (3)
Venetsanos, Dimitrio ... (3)
Bech-Hanssen, Odd, 1 ... (3)
Alwmark, Carl (3)
Bleeker, Wouter (3)
Omerovic, Elmir (3)
Östlund, Ollie (3)
Andersson, Jenny (3)
Sarno, Giovanna (3)
Scherstén, Fredrik (3)
Eriksson, Peter (3)
Nilsson, Folke, 1950 (3)
Bjärnborg, Karolina (3)
Hamid, Mehmet (3)
Kemp, A.I.S. (3)
Grimfjärd, Per (3)
Danielewicz, Mikael (3)
van Schijndel, Valby (3)
Henareh, Loghman (3)
Muenker, Carsten (3)
Rosing, Minik T. (3)
Schumacher, John C. (3)
show less...
University
Lund University (65)
University of Gothenburg (21)
Swedish Museum of Natural History (12)
Uppsala University (8)
Stockholm University (8)
Karolinska Institutet (8)
show more...
Örebro University (7)
Umeå University (4)
Linköping University (4)
Luleå University of Technology (2)
show less...
Language
English (83)
Swedish (4)
Undefined language (1)
Research subject (UKÄ/SCB)
Natural sciences (64)
Medical and Health Sciences (21)
Social Sciences (1)
Humanities (1)

Year

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Close

Copy and save the link in order to return to this view