| 1. |
- Khotyaintsev, Yuri V., et al.
(författare)
-
Electron jet of asymmetric reconnection
- 2016
-
Ingår i: Geophysical Research Letters. - : Blackwell Publishing. - 0094-8276 .- 1944-8007. ; 43:11, s. 5571-5580
-
Tidskriftsartikel (refereegranskat)abstract
- We present Magnetospheric Multiscale observations of an electron-scale current sheet and electron outflow jet for asymmetric reconnection with guide field at the subsolar magnetopause. The electron jet observed within the reconnection region has an electron Mach number of 0.35 and is associated with electron agyrotropy. The jet is unstable to an electrostatic instability which generates intense waves with E-vertical bar amplitudes reaching up to 300mVm(-1) and potentials up to 20% of the electron thermal energy. We see evidence of interaction between the waves and the electron beam, leading to quick thermalization of the beam and stabilization of the instability. The wave phase speed is comparable to the ion thermal speed, suggesting that the instability is of Buneman type, and therefore introduces electron-ion drag and leads to braking of the electron flow. Our observations demonstrate that electrostatic turbulence plays an important role in the electron-scale physics of asymmetric reconnection.
|
|
| 2. |
- Le Contel, O., et al.
(författare)
-
Lower Hybrid Drift Waves and Electromagnetic Electron Space-Phase Holes Associated With Dipolarization Fronts and Field-Aligned Currents Observed by the Magnetospheric Multiscale Mission During a Substorm
- 2017
-
Ingår i: Journal of Geophysical Research - Space Physics. - : AMER GEOPHYSICAL UNION. - 2169-9380 .- 2169-9402. ; 122:12, s. 12236-12257
-
Tidskriftsartikel (refereegranskat)abstract
- We analyze two ion scale dipolarization fronts associated with field-aligned currents detected by the Magnetospheric Multiscale mission during a large substorm on 10 August 2016. The first event corresponds to a fast dawnward flow with an antiparallel current and could be generated by the wake of a previous fast earthward flow. It is associated with intense lower hybrid drift waves detected at the front and propagating dawnward with a perpendicular phase speed close to the electric drift and the ion thermal velocity. The second event corresponds to a flow reversal: from southwward/dawnward to northward/duskward associated with a parallel current consistent with a brief expansion of the plasma sheet before the front crossing and with a smaller lower hybrid drift wave activity. Electromagnetic electron phase-space holes are detected near these low-frequency drift waves during both events. The drift waves could accelerate electrons parallel to the magnetic field and produce the parallel electron drift needed to generate the electron holes. Yet we cannot rule out the possibility that the drift waves are produced by the antiparallel current associated with the fast flows, leaving the source for the electron holes unexplained.
|
|
| 3. |
- Lundgren, Fredrik, et al.
(författare)
-
PTFE bypass to below-knee arteries : distal vein collar or not? A prospective randomised multicentre study
- 2010
-
Ingår i: European Journal of Vascular and Endovascular Surgery. - : Elsevier BV. - 1078-5884 .- 1532-2165. ; 39:6, s. 747-754
-
Tidskriftsartikel (refereegranskat)abstract
- BackgroundPatency and limb salvage after synthetic bypass to the arteries below-knee are inferior to that which can be achieved with autologous vein. Use of a vein collar at the distal anastomosis has been suggested to improve patency and limb salvage, a problem that is analysed in this randomised clinical study.MethodsPatients with critical limb ischaemia undergoing polytetrafluoroethylene (PTFE) bypass to below-knee arteries were randomly either assigned a vein collar or not in two groups – bypass to the popliteal artery below-knee (femoro-popliteal below-knee (FemPopBK)) and more distal bypass (femoro-distal bypass (FemDist)). Follow-up was scheduled until amputation, death or at most 5 years, whichever event occurred first.ResultsIn the FemPopBK and in the FemDist groups, 115/202 and 72/150 were randomised to have a vein collar, respectively. Information was available for 345 of 352 randomised patients (98%).At 3 years, primary patency was 26% (95% confidence interval (CI) 18–38) with a vein collar and 43 (33–58) without a vein collar for femoro-popliteal bypass and 20 (11–38), and 17 (9–33) for femoro-distal bypass, respectively. The corresponding figures for limb salvage were 64 (54–75) and 61 (50–74) for femoro-popliteal bypass, and 59 (46–76) and 44 (32–61) for femoro-distal bypass with and without a vein collar, respectively. Log-rank-test for the whole Kaplan–Meier life table curve showed no statistically significant differences with or without vein collar primary patency: p = 0.0853, p = 0.228; secondary patency: p = 0.317, p = 0.280; limb salvage: p = 0.757, p = 0.187 for FemPopBK and FemDist, respectively. The use of a vein collar did not influence patency or limb salvage.ConclusionThis study failed to show any benefit for vein collar with PTFE bypass to a below-knee artery.
|
|
| 4. |
- Norgren, Cecilia, et al.
(författare)
-
Finite gyroradius effects in the electron outflow of asymmetric magnetic reconnection
- 2016
-
Ingår i: Geophysical Research Letters. - : Blackwell Publishing. - 0094-8276 .- 1944-8007. ; 43:13, s. 6724-6733
-
Tidskriftsartikel (refereegranskat)abstract
- We present observations of asymmetric magnetic reconnection showing evidence of electron demagnetization in the electron outflow. The observations were made at the magnetopause by the four Magnetospheric Multiscale (MMS) spacecraft, separated by approximate to 15km. The reconnecting current sheet has negligible guide field, and all four spacecraft likely pass close to the electron diffusion region just south of the X line. In the electron outflow near the X line, all four spacecraft observe highly structured electron distributions in a region comparable to a few electron gyroradii. The distributions consist of a core with T-vertical bar>T and a nongyrotropic crescent perpendicular to the magnetic field. The crescents are associated with finite gyroradius effects of partly demagnetized electrons. These observations clearly demonstrate the manifestation of finite gyroradius effects in an electron-scale reconnection current sheet.
|
|
| 5. |
|
|
| 6. |
- Fuselier, S. A., et al.
(författare)
-
Large-scale characteristics of reconnection diffusion regions and associated magnetopause crossings observed by MMS
- 2017
-
Ingår i: Journal of Geophysical Research - Space Physics. - 2169-9380 .- 2169-9402. ; 122:5, s. 5466-5486
-
Tidskriftsartikel (refereegranskat)abstract
- The Magnetospheric Multiscale (MMS) mission was designed to make observations in the very small electron diffusion region (EDR), where magnetic reconnection takes place. From a data set of over 4500 magnetopause crossings obtained in the first phase of the mission, MMS had encounters near or within 12 EDRs. These 12 events and associated magnetopause crossings are considered as a group to determine if they span the widest possible range of external and internal conditions (i.e., in the solar wind and magnetosphere). In addition, observations from MMS are used to determine if there are multiple X-lines present and also to provide information on X-line location relative to the spacecraft. These 12 events represent nearly the widest possible range of conditions at the dayside magnetopause. They occur over a wide range of local times and magnetic shear angles between the magnetosheath and magnetospheric magnetic fields. Most show evidence for multiple reconnection sites.
|
|
| 7. |
- Graham, Daniel B., et al.
(författare)
-
Electron currents and heating in the ion diffusion region of asymmetric reconnection
- 2016
-
Ingår i: Geophysical Research Letters. - : American Geophysical Union (AGU). - 0094-8276 .- 1944-8007. ; 43:10, s. 4691-4700
-
Tidskriftsartikel (refereegranskat)abstract
- In this letter the structure of the ion diffusion region of magnetic reconnection at Earth's magnetopause is investigated using the Magnetospheric Multiscale (MMS) spacecraft. The ion diffusion region is characterized by a strong DC electric field, approximately equal to the Hall electric field, intense currents, and electron heating parallel to the background magnetic field. Current structures well below ion spatial scales are resolved, and the electron motion associated with lower hybrid drift waves is shown to contribute significantly to the total current density. The electron heating is shown to be consistent with large-scale parallel electric fields trapping and accelerating electrons, rather than wave-particle interactions. These results show that sub-ion scale processes occur in the ion diffusion region and are important for understanding electron heating and acceleration.
|
|
| 8. |
- Graham, Daniel B., et al.
(författare)
-
Lower hybrid waves in the ion diffusion and magnetospheric inflow regions
- 2017
-
Ingår i: Journal of Geophysical Research - Space Physics. - : AMER GEOPHYSICAL UNION. - 2169-9380 .- 2169-9402. ; 122:1, s. 517-533
-
Tidskriftsartikel (refereegranskat)abstract
- The role and properties of lower hybrid waves in the ion diffusion region and magnetospheric inflow region of asymmetric reconnection are investigated using the Magnetospheric Multiscale (MMS) mission. Two distinct groups of lower hybrid waves are observed in the ion diffusion region and magnetospheric inflow region, which have distinct properties and propagate in opposite directions along the magnetopause. One group develops near the ion edge in the magnetospheric inflow, where magnetosheath ions enter the magnetosphere through the finite gyroradius effect and are driven by the ion-ion cross-field instability due to the interaction between the magnetosheath ions and cold magnetospheric ions. This leads to heating of the cold magnetospheric ions. The second group develops at the sharpest density gradient, where the Hall electric field is observed and is driven by the lower hybrid drift instability. These drift waves produce cross-field particle diffusion, enabling magnetosheath electrons to enter the magnetospheric inflow region thereby broadening the density gradient in the ion diffusion region.
|
|
| 9. |
- Vaivads, Andris, et al.
(författare)
-
Turbulence Heating ObserveR - satellite mission proposal
- 2016
-
Ingår i: JOURNAL OF PLASMA PHYSICS. - 0022-3778. ; 82
-
Tidskriftsartikel (refereegranskat)abstract
- The Universe is permeated by hot, turbulent, magnetized plasmas. Turbulent plasma is a major constituent of active galactic nuclei, supernova remnants, the intergalactic and interstellar medium, the solar corona, the solar wind and the Earth's magnetosphere, just to mention a few examples. Energy dissipation of turbulent fluctuations plays a key role in plasma heating and energization, yet we still do not understand the underlying physical mechanisms involved. THOR is a mission designed to answer the questions of how turbulent plasma is heated and particles accelerated, how the dissipated energy is partitioned and how dissipation operates in different regimes of turbulence. THOR is a single-spacecraft mission with an orbit tuned to maximize data return from regions in near-Earth space - magnetosheath, shock, foreshock and pristine solar wind - featuring different kinds of turbulence. Here we summarize the THOR proposal submitted on 15 January 2015 to the 'Call for a Medium-size mission opportunity in ESAs Science Programme for a launch in 2025 (M4)'. THOR has been selected by European Space Agency (ESA) for the study phase.
|
|
| 10. |
- Belch, Jill J. F., et al.
(författare)
-
Results of the randomized, placebo-controlled clopidogrel and acetylsalicylic acid in bypass surgery for peripheral arterial disease (CASPAR) trial
- 2010
-
Ingår i: Journal of vascular surgery : official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter. - : Elsevier BV. - 0741-5214. ; 52:4, s. 825-833, 833.e1-2
-
Tidskriftsartikel (refereegranskat)abstract
- The combination of clopidogrel plus ASA did not improve limb or systemic outcomes in the overall population of PAD patients requiring below-knee bypass grafting. Subgroup analysis suggests that clopidogrel plus ASA confers benefit in patients receiving prosthetic grafts without significantly increasing major bleeding risk.
|
|
| 11. |
- Benterud, T, et al.
(författare)
-
N-Acetylcysteine Amide Exerts Possible Neuroprotective Effects in Newborn Pigs after Perinatal Asphyxia
- 2017
-
Ingår i: Neonatology. - : S. Karger AG. - 1661-7819 .- 1661-7800. ; 111:1, s. 12-21
-
Tidskriftsartikel (refereegranskat)abstract
- <b><i>Background:</i></b> Perinatal asphyxia and ensuing reoxygenation change the antioxidant capacity of cells and organs. <b><i>Objectives:</i></b> To analyze the neuroprotective effect of the antioxidant N-acetylcysteine amide (NACA) after perinatal hypoxia-reoxygenation with an emphasis on proinflammatory cytokines and the transcription factor NF-κB in the prefrontal cortex of neonatal pigs. <b><i>Methods:</i></b> Twenty-nine newborn pigs, aged 12-36 h, were subjected to global hypoxia and hypercapnia. One sham-operated group (n = 5) and 2 experimental groups (n = 12) were exposed to 8% oxygen, until the base excess was -20 mmol/l or the mean arterial blood pressure fell to <20 mm Hg (asphyxia with NACA or saline). The pigs were observed for 9.5 h after hypoxia. Samples of prefrontal cortex and plasma were analyzed. <b><i>Results:</i></b> Cortex: there was no significant difference in mRNA expression between the intervention groups regarding IL-1β, IL6, TNFα, MMP2, MMP9 or IL18. Pigs exposed to hypoxia-reoxygenation and treatment with NACA (NACA-pigs) had a significantly lower protein concentration of IL-1β than pigs treated with saline (placebo controls), i.e. 8.8 ± 3.9 versus 16.8 ± 10.5 pg/mg protein (p = 0.02). The activation of the transcription factor NF-κB (measured as the fold-change of phosphorylated p65<sup>Ser 536</sup>), was reduced in the NACA-pigs when compared to the placebo controls (5.2 ± 4.3 vs. 16.0 ± 13.5; p = 0.02). No difference between the intervention groups regarding brain histopathology or in the levels of 8-oxoguanine measured in the prefrontal cortex were observed. Plasma: the NACA-pigs had a stronger reduction of TNFα in the first 30 min following asphyxia compared with the placebo controls, i.e. 36 (30-44) versus 24 (14-32)% (p = 0.01). <b><i>Conclusion:</i></b> The reduced levels of the pivotal inflammatory markers IL-1β and TNFα and the transcription factor NF-κB may indicate that NACA has possible neuroprotective effects after perinatal asphyxia.
|
|
| 12. |
- Graham, Daniel B., et al.
(författare)
-
Instability of Agyrotropic Electron Beams near the Electron Diffusion Region
- 2017
-
Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 119:2
-
Tidskriftsartikel (refereegranskat)abstract
- During a magnetopause crossing the Magnetospheric Multiscale spacecraft encountered an electron diffusion region (EDR) of asymmetric reconnection. The EDR is characterized by agyrotropic beam and crescent electron distributions perpendicular to the magnetic field. Intense upper-hybrid (UH) waves are found at the boundary between the EDR and magnetosheath inflow region. The UH waves are generated by the agyrotropic electron beams. The UH waves are sufficiently large to contribute to electron diffusion and scattering, and are a potential source of radio emission near the EDR. These results provide observational evidence of wave-particle interactions at an EDR, and suggest that waves play an important role in determining the electron dynamics.
|
|
| 13. |
- Halliday, Alison, et al.
(författare)
-
10-year stroke prevention after successful carotid endarterectomy for asymptomatic stenosis (ACST-1) : A multicentre randomised trial
- 2010
-
Ingår i: The Lancet. - 0140-6736 .- 1474-547X. ; 376:9746, s. 1074-1084
-
Tidskriftsartikel (refereegranskat)abstract
- Background If carotid artery narrowing remains asymptomatic (ie, has caused no recent stroke or other neurological symptoms), successful carotid endarterectomy (CEA) reduces stroke incidence for some years. We assessed the long-term effects of successful CEA. Methods Between 1993 and 2003, 3120 asymptomatic patients from 126 centres in 30 countries were allocated equally, by blinded minimised randomisation, to immediate CEA (median delay 1 month, IQR 0·3-2·5) or to indefinite deferral of any carotid procedure, and were followed up until death or for a median among survivors of 9 years (IQR 6-11). The primary outcomes were perioperative mortality and morbidity (death or stroke within 30 days) and non-perioperative stroke. Kaplan-Meier percentages and logrank p values are from intention-to-treat analyses. This study is registered, number ISRCTN26156392. Findings 1560 patients were allocated immediate CEA versus 1560 allocated deferral of any carotid procedure. The proportions operated on while still asymptomatic were 89·7 versus 4·8 at 1 year (and 92·1 vs 16·5 at 5 years). Perioperative risk of stroke or death within 30 days was 3·0 (95 CI 2·4-3·9; 26 non-disabling strokes plus 34 disabling or fatal perioperative events in 1979 CEAs). Excluding perioperative events and non-stroke mortality, stroke risks (immediate vs deferred CEA) were 4·1 versus 10·0 at 5 years (gain 5·9, 95 CI 4·0-7·8) and 10·8 versus 16·9 at 10 years (gain 6·1, 2·7-9·4); ratio of stroke incidence rates 0·54, 95 CI 0·43-0·68, p<0·0001. 62 versus 104 had a disabling or fatal stroke, and 37 versus 84 others had a non-disabling stroke. Combining perioperative events and strokes, net risks were 6·9 versus 10·9 at 5 years (gain 4·1, 2·0-6·2) and 13·4 versus 17·9 at 10 years (gain 4·6, 1·2-7·9). Medication was similar in both groups; throughout the study, most were on antithrombotic and antihypertensive therapy. Net benefits were significant both for those on lipid-lowering therapy and for those not, and both for men and for women up to 75 years of age at entry (although not for older patients). Interpretation Successful CEA for asymptomatic patients younger than 75 years of age reduces 10-year stroke risks. Half this reduction is in disabling or fatal strokes. Net benefit in future patients will depend on their risks from unoperated carotid lesions (which will be reduced by medication), on future surgical risks (which might differ from those in trials), and on whether life expectancy exceeds 10 years. Funding UK Medical Research Council, BUPA Foundation, Stroke Association.
|
|
| 14. |
- Hwang, K.-J., et al.
(författare)
-
Bifurcated Current Sheet Observed on the Boundary of Kelvin-Helmholtz Vortices
- 2021
-
Ingår i: Frontiers in Astronomy and Space Sciences. - : Frontiers Media S.A.. - 2296-987X. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- On May 5, 2017 MMS observed a bifurcated current sheet at the boundary of Kelvin-Helmholtz vortices (KHVs) developed on the dawnside tailward magnetopause. We use the event to enhance our understanding of the formation and structure of asymmetric current sheets in the presence of density asymmetry, flow shear, and guide field, which have been rarely studied. The entire current layer comprises three separate current sheets, each corresponding to magnetosphere-side sunward separatrix region, central near-X-line region, and magnetosheath-side tailward separatrix region. Two off-center structures are identified as slow-mode discontinuities. All three current sheets have a thickness of ∼0.2 ion inertial length, demonstrating the sub-ion-scale current layer, where electrons mainly carry the current. We find that both the diamagnetic and electron anisotropy currents substantially support the bifurcated currents in the presence of density asymmetry and weak velocity shear. The combined effects of strong guide field, low density asymmetry, and weak flow shear appear to lead to asymmetries in the streamlines and the current-layer structure of the quadrupolar reconnection geometry. We also investigate intense electrostatics waves observed on the magnetosheath side of the KHV boundary. These waves may pre-heat a magnetosheath population that is to participate into the reconnection process, leading to two-step energization of the magnetosheath plasma entering into the magnetosphere via KHV-driven reconnection.
|
|
| 15. |
- Larzon, Thomas, 1950-, et al.
(författare)
-
Editor's choice : a randomized controlled trial of the fascia suture technique compared with a suture-mediated closure device for femoral arterial closure after endovascular aortic repair
- 2015
-
Ingår i: European Journal of Vascular and Endovascular Surgery. - : W.B. Saunders Ltd. - 1078-5884 .- 1532-2165. ; 49:2, s. 166-173
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives: The aim was to investigate whether the fascia suture technique (FST) can reduce access closure time and procedural costs compared with the Prostar technique (Prostar) in patients undergoing endovascular aortic repair and to evaluate the short- and mid-term outcomes of both techniques.Methods: In this two center trial, 100 patients were randomized to access closure by either FST or Prostar between June 2006 and December 2009. The primary endpoint was access closure time. Secondary outcome measures included access related costs and evaluation of the short- and mid-term complications. Evaluation was performed pen- and post-operatively, at discharge, at 30 days and at 6 months follow up.Results: The median access closure time was 12.4 minutes for FST and 19.9 minutes for Prostar (p < .001). Prostar required a 54% greater procedure time than FST, mean ratio 1.54 (95% Cl 1.25-1.90, p < .001) according to regression analysis. Adjusted for operator experience the mean ratio was 1.30 (95% Cl 1.09-1.55, p = .005) and for patient body mass index 1.59 (95% Cl 1.28-1.96, p < .001). The technical failure rate for operators at proficiency level was 5% (2/40) compared with 28% (17/59) for those at the basic level (p = .003). The proficiency level group had a technical failure rate of 4% (1/26) for FST and 7% (1/14) for Prostar, p = 1.00, while corresponding rates for the basic level group were 27% (6/22) for FST and 30% (11/37) for Prostar (p = .84). There was a significant difference in cost in favor. of FST, with a median difference of (sic)800 (95% Cl 710-927, p < .001). Conclusions: In aortic endovascular repair FST is a faster and cheaper technique than the Prostar technique.
|
|
| 16. |
- Li, Wenya, et al.
(författare)
-
Kinetic evidence of magnetic reconnection due to Kelvin-Helmholtz waves
- 2016
-
Ingår i: Geophysical Research Letters. - : Blackwell Publishing. - 0094-8276 .- 1944-8007. ; 43:11, s. 5635-5643
-
Tidskriftsartikel (refereegranskat)abstract
- The Kelvin-Helmholtz (KH) instability at the Earth's magnetopause is predominantly excited during northward interplanetary magnetic field (IMF). Magnetic reconnection due to KH waves has been suggested as one of the mechanisms to transfer solar wind plasma into the magnetosphere. We investigate KH waves observed at the magnetopause by the Magnetospheric Multiscale (MMS) mission; in particular, we study the trailing edges of KH waves with Alfvenic ion jets. We observe gradual mixing of magnetospheric and magnetosheath ions at the boundary layer. The magnetospheric electrons with energy up to 80keV are observed on the magnetosheath side of the jets, which indicates that they escape into the magnetosheath through reconnected magnetic field lines. At the same time, the low-energy (below 100eV) magnetosheath electrons enter the magnetosphere and are heated in the field-aligned direction at the high-density edge of the jets. Our observations provide unambiguous kinetic evidence for ongoing reconnection due to KH waves.
|
|
| 17. |
- Li, Wenya, et al.
(författare)
-
Upper-Hybrid Waves Driven by Meandering Electrons Around Magnetic Reconnection X Line
- 2021
-
Ingår i: Geophysical Research Letters. - : American Geophysical Union (AGU). - 0094-8276 .- 1944-8007. ; 48:16
-
Tidskriftsartikel (refereegranskat)abstract
- Magnetic reconnection is a fundamental process in collisionless space plasma environment, and plasma waves relevant to the kinetic interactions can have a significant impact on the multiscale behavior of reconnection. Here, we present Magnetospheric Multiscale (MMS) observations during an encounter of an X line of symmetric magnetic reconnection in the magnetotail. The X line is characterized by reversals of ion and electron jets and electromagnetic fields, agyrotropic electron velocity distribution functions (VDFs), and an electron-scale current sheet. MMS observe large-amplitude nonlinear upper-hybrid (UH) waves on both sides of the neutral line, and the wave amplitudes have highly localized distribution along the normal direction. The inbound meandering electrons drive the UH waves, releasing the free energy stored from the reconnection electric field along the meandering trajectories. The interaction between the meandering electrons and the UH waves may modify the balance of the reconnection electric field around the X line. Plain Language Summary The electron-scale kinetic physics in the electron diffusion region (EDR) controls how magnetic field lines break and reconnect. Electron crescent, an indicator of EDR, can drive high-frequency electrostatic waves around EDR. For the first time, the upper-hybrid (UH) waves are observed on both sides of the X line and we show the direct association between the UH waves and the reconnection electric field. The strong wave-electron interaction can change the electron-scale dynamics and may modify the reconnection electric field. This study demonstrates that the UH waves may play an important role in controlling the reconnection rate.
|
|
| 18. |
- Li, W. Y., et al.
(författare)
-
Electron Bernstein waves driven by electron crescents near the electron diffusion region
- 2020
-
Ingår i: Nature Communications. - : Nature Research. - 2041-1723. ; 11:1
-
Tidskriftsartikel (refereegranskat)abstract
- The Magnetospheric Multiscale (MMS) spacecraft encounter an electron diffusion region (EDR) of asymmetric magnetic reconnection at Earth’s magnetopause. The EDR is characterized by agyrotropic electron velocity distributions on both sides of the neutral line. Various types of plasma waves are produced by the magnetic reconnection in and near the EDR. Here we report large-amplitude electron Bernstein waves (EBWs) at the electron-scale boundary of the Hall current reversal. The finite gyroradius effect of the outflow electrons generates the crescent-shaped agyrotropic electron distributions, which drive the EBWs. The EBWs propagate toward the central EDR. The amplitude of the EBWs is sufficiently large to thermalize and diffuse electrons around the EDR. The EBWs contribute to the cross-field diffusion of the electron-scale boundary of the Hall current reversal near the EDR.
|
|
| 19. |
- Lindman, Björn, et al.
(författare)
-
Hydrophobic interactions control the self-assembly of DNA and cellulose
- 2021
-
Ingår i: Quarterly reviews of biophysics (Print). - 0033-5835 .- 1469-8994. ; 54
-
Tidskriftsartikel (refereegranskat)abstract
- Desoxyribosenucleic acid, DNA, and cellulose molecules self-assemble in aqueous systems. This aggregation is the basis of the important functions of these biological macromolecules. Both DNA and cellulose have significant polar and nonpolar parts and there is a delicate balance between hydrophilic and hydrophobic interactions. The hydrophilic interactions related to net charges have been thoroughly studied and are well understood. On the other hand, the detailed roles of hydrogen bonding and hydrophobic interactions have remained controversial. It is found that the contributions of hydrophobic interactions in driving important processes, like the double-helix formation of DNA and the aqueous dissolution of cellulose, are dominating whereas the net contribution from hydrogen bonding is small. In reviewing the roles of different interactions for DNA and cellulose it is useful to compare with the self-assembly features of surfactants, the simplest case of amphiphilic molecules. Pertinent information on the amphiphilic character of cellulose and DNA can be obtained from the association with surfactants, as well as on modifying the hydrophobic interactions by additives.
|
|
| 20. |
|
|
| 21. |
|
|
| 22. |
- Voros, Z., et al.
(författare)
-
MMS Observation of Magnetic Reconnection in the Turbulent Magnetosheath
- 2017
-
Ingår i: Journal of Geophysical Research - Space Physics. - : AMER GEOPHYSICAL UNION. - 2169-9380 .- 2169-9402. ; 122:11, s. 11442-11467
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper we use the full armament of the MMS (Magnetospheric Multiscale) spacecraft to study magnetic reconnection in the turbulent magnetosheath downstream of a quasi-parallel bow shock. Contrarily to the magnetopause and magnetotail cases, only a few observations of reconnection in the magnetosheath have been reported. The case study in this paper presents, for the first time, both fluid-scale and kinetic-scale signatures of an ongoing reconnection in the turbulent magnetosheath. The spacecraft are crossing the reconnection inflow and outflow regions and the ion diffusion region (IDR). Inside the reconnection outflows D shape ion distributions are observed. Inside the IDR mixing of ion populations, crescent-like velocity distributions and ion accelerations are observed. One of the spacecraft skims the outer region of the electron diffusion region, where parallel electric fields, energy dissipation/conversion, electron pressure tensor agyrotropy, electron temperature anisotropy, and electron accelerations are observed. Some of the difficulties of the observations of magnetic reconnection in turbulent plasma are also outlined.
|
|
| 23. |
- Yordanova, Emiliya, et al.
(författare)
-
Electron scale structures and magnetic reconnection signatures in the turbulent magnetosheath
- 2016
-
Ingår i: Geophysical Research Letters. - : Blackwell Publishing. - 0094-8276 .- 1944-8007. ; 43:12, s. 5969-5978
-
Tidskriftsartikel (refereegranskat)abstract
- Collisionless space plasma turbulence can generate reconnecting thin current sheets as suggested by recent results of numerical magnetohydrodynamic simulations. The Magnetospheric Multiscale (MMS) mission provides the first serious opportunity to verify whether small ion-electron-scale reconnection, generated by turbulence, resembles the reconnection events frequently observed in the magnetotail or at the magnetopause. Here we investigate field and particle observations obtained by the MMS fleet in the turbulent terrestrial magnetosheath behind quasi-parallel bow shock geometry. We observe multiple small-scale current sheets during the event and present a detailed look of one of the detected structures. The emergence of thin current sheets can lead to electron scale structures. Within these structures, we see signatures of ion demagnetization, electron jets, electron heating, and agyrotropy suggesting that MMS spacecraft observe reconnection at these scales.
|
|
| 24. |
|
|
| 25. |
|
|
| 26. |
|
|
| 27. |
- André, Mats, et al.
(författare)
-
Lower hybrid waves at comet 67P/Churyumov-Gerasimenko
- 2017
-
Ingår i: Monthly notices of the Royal Astronomical Society. - : OXFORD UNIV PRESS. - 0035-8711 .- 1365-2966. ; 469, s. S29-S38
-
Tidskriftsartikel (refereegranskat)abstract
- We investigate the generation of waves in the lower hybrid frequency range by density gradients in the near plasma environment of comet 67P/Churyumov-Gerasimenko. When the plasma is dominated by water ions from the comet, a situation with magnetized electrons and unmagnetized ions is favourable for the generation of lower hybrid waves. These waves can transfer energy between ions and electrons and reshape the plasma environment of the comet. We consider cometocentric distances out to a few hundred km. We find that when the electron motion is not significantly interrupted by collisions with neutrals, large average gradients within tens of km of the comet, as well as often observed local large density gradients at larger distances, are often likely to be favourable for the generation of lower hybrid waves. Overall, we find that waves in the lower hybrid frequency range are likely to be common in the near plasma environment.
|
|
| 28. |
- André, Mats, et al.
(författare)
-
Magnetic reconnection and modification of the Hall physics due to cold ions at the magnetopause
- 2016
-
Ingår i: Geophysical Research Letters. - : Blackwell Publishing. - 0094-8276 .- 1944-8007. ; 43:13, s. 6705-6712
-
Tidskriftsartikel (refereegranskat)abstract
- Observations by the four Magnetospheric Multiscale spacecraft are used to investigate the Hall physics of a magnetopause magnetic reconnection separatrix layer. Inside this layer of currents and strong normal electric fields, cold (eV) ions of ionospheric origin can remain frozen-in together with the electrons. The cold ions reduce the Hall current. Using a generalized Ohm's law, the electric field is balanced by the sum of the terms corresponding to the Hall current, the vxB drifting cold ions, and the divergence of the electron pressure tensor. A mixture of hot and cold ions is common at the subsolar magnetopause. A mixture of length scales caused by a mixture of ion temperatures has significant effects on the Hall physics of magnetic reconnection.
|
|
| 29. |
|
|
| 30. |
- Berger, J. S., et al.
(författare)
-
Design and rationale for the Effects of Ticagrelor and Clopidogrel in Patients with Peripheral Artery Disease (EUCLID) trial
- 2016
-
Ingår i: American Heart Journal. - : Elsevier BV. - 0002-8703. ; 175, s. 86-93
-
Tidskriftsartikel (refereegranskat)abstract
- Background Despite overwhelming data demonstrating the efficacy of antiplatelet therapy in heart disease and stroke, data in peripheral artery disease (PAD) are less compelling. Aspirin has modest evidence supporting a reduction in cardiovascular events in patients with PAD, whereas clopidogrel monotherapy may be more effective in PAD. Ticagrelor, a potent, reversibly binding P2Y(12) receptor antagonist, is beneficial in patients with acute coronary syndrome and prior myocardial infarction. The EUCLID trial is designed to address the need for effective antiplatelet therapy in PAD to decrease the risk of cardiovascular events. Study design EUCLID is a randomized, double-blind, parallel-group, multinational clinical trial designed to evaluate the efficacy and safety of ticagrelor compared with clopidogrel for the prevention of major adverse cardiovascular events in subjects with symptomatic PAD. Subjects with established PAD will be randomized in a 1: 1 fashion to ticagrelor 90 mg twice daily or clopidogrel 75 mg daily. The primary end point is a composite of cardiovascular death, myocardial infarction, or ischemic stroke. Other end points address limb events including acute leg ischemia, need for revascularization, disease progression by ankle-brachial index, and quality of life. The primary safety objective is Thrombolysis in Myocardial Infarction-defined major bleeding. Recruitment began in December 2012 and was completed in March 2014; 13,887 patients were randomized. The trial will continue until at least 1,364 adjudicated primary end points occur. Conclusions The EUCLID study is investigating whether treatment with ticagrelor versus clopidogrel, given as antiplatelet monotherapy, will reduce the incidence of cardiovascular and limb-specific events in patients with symptomatic PAD.
|
|
| 31. |
|
|
| 32. |
|
|
| 33. |
|
|
| 34. |
|
|
| 35. |
- Danielsson, P., et al.
(författare)
-
Systemic white blood and endothelial cell response after revascularization of critical limb ischemia is only influenced in case of ischemic ulcers
- 2006
-
Ingår i: International Journal of Angiology. - 0392-9590 .- 1827-1839. ; 25:3, s. 310-315
-
Tidskriftsartikel (refereegranskat)abstract
- AIM: The aim of this study was to study the inflammatory response to open revascularization of an ischemic leg in terms of activation of white blood cells (WBC), platelets and endothelial cells. DESIGN: prospective study. METHODS: Venous samples from 21 patients suffering critical limb ischemia (CLI) were drawn before, and 4 weeks after (20 patients) revascularization. Total WBC, differentiated WBC, and platelets were counted. Expression of CD11b/CD18 on granulocytes and monocytes and CD41 on platelets was measured by flow cytometry. Soluble endothelial markers (sICAM-1, sVCAM-1, sE-selectin and sP-selectin) were analysed with ELISA. RESULTS: WBC and granulocyte count decreased in the subgroup of patients with ulcer and gangrene but no change in activation of WBC was recorded. The endothelial marker sICAM-1 decreased while VCAM-1 increased following surgery, most evident in the subgroup with ulcers and gangrene. CONCLUSIONS: This study shows that revascularization of CLI does not significantly influence the inflammatory response in patients with rest pain only, but a limited response of down regulation was found in the ulcer/gangrene patients probably as an effect of healing ulcers.
|
|
| 36. |
- Dekki, N, et al.
(författare)
-
Type 1 diabetic serum interferes with pancreatic beta-cell Ca2+-handling
- 2007
-
Ingår i: Bioscience reports. - : Portland Press Ltd.. - 0144-8463 .- 1573-4935. ; 27:6, s. 321-326
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to clarify the frequency of patients with type 1 diabetes that have serum that increases pancreatic β-cell cytoplasmic free Ca2+ concentration, [Ca2+]i, and if such an effect is also present in serum from first-degree relatives. We also studied a possible link between the serum effect and ethnic background as well as presence of autoantibodies. Sera obtained from three different countries were investigated as follows: 82 Swedish Caucasians with newly diagnosed type 1 diabetes, 56 Americans with different duration of type 1 diabetes, 117 American first-degree relatives of type 1 diabetic patients with a mixed ethnic background and 31 Caucasian Finnish children with newly diagnosed type 1 diabetes. Changes in [Ca2+]i, upon depolarization, were measured in β-cells incubated overnight with sera from type 1 diabetic patients, first-degree relatives or healthy controls. Our data show that there is a group constituting approximately 30% of type 1 diabetic patients of different gender, age, ethnic background and duration of the disease, as well as first-degree relatives of type 1 diabetic patients, that have sera that interfere with pancreatic β-cell Ca2+-handling. This effect on β-cell [Ca2+]i could not be correlated to the presence of autoantibodies. In a defined subgroup of patients with type 1 diabetes and first-degree relatives a defect Ca2+-handling may aggravate development of β-cell destruction.
|
|
| 37. |
- Dyal Ukabhai, K., et al.
(författare)
-
Formation of Ti2Cu in Ti-Cu Alloys
- 2022
-
Ingår i: JOURNAL OF PHASE EQUILIBRIA AND DIFFUSION. - : Springer Nature. - 1547-7037 .- 1863-7345. ; 43:3, s. 332-344
-
Tidskriftsartikel (refereegranskat)abstract
- One of the major issues with dental implants is failure due to bacterial infection, and additions of copper are known to improve the antimicrobial properties of Ti alloys. There are inconsistencies in the Ti rich area of the Cu-Ti binary phase diagram, hence the need to find out if Ti2Cu or Ti3Cu is formed, and to identify the type of formation of Ti2Cu. Four alloys: 20, 33, 40 and 50 Cu (mass%) were produced by arc melting and studied using SEM, XRD and DSC. The reactions were derived, and the temperatures of the reactions were determined by DSC. The formation of Ti2Cu is congruent, and no Ti3Cu was found.
|
|
| 38. |
|
|
| 39. |
- Engellau, Lena, et al.
(författare)
-
Measurements before endovascular repair of abdominal aortic aneurysms : MR imaging with MRA vs. angiography and CT
- 2003
-
Ingår i: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 44:2, s. 177-184
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: 1) To compare measurements obtained with MR imaging (MRI)/contrast-enhanced MR angiography (CE MRA) with measurements obtained with angiography (DSA) and CT, for stent-graft sizing of abdominal aortic aneurysms (AAA). 2) To compare MRA measurements obtained with the two post processing techniques MIP (maximum intensity projection) and VRT (3D volume rendering technique).Material and Methods: The prospective study included 20 consecutive patients with AAA identified by DSA and CT as suitable for endovascular repair. For the study, MRI/CE MRA was performed. Five measurement variables for stent-graft sizing were chosen. Comparisons were made between MRI/CE MRA, DSA and CT, and between observers. Comparisons were also made between MIP and VRT.Results: Significantly shorter lengths were obtained with MRA-MIP than with DSA. Three out of six diameter measurements were significantly smaller on MRI/CE MRA than on DSA and CT. No significant differences were found between the observers. One diameter measurement was significantly smaller on MIP than on VRT, while the other measurements showed no significant differences.Conclusion: The length measurements obtained with MRA-MIP were probably more correct than those with DSA. For more reliable diameter measurements with CE MRA, improvements of the technique, including VRT reconstructions and a standardized determination of the vessel boundaries, are needed.
|
|
| 40. |
|
|
| 41. |
|
|
| 42. |
|
|
| 43. |
|
|
| 44. |
- Graham, D. B., et al.
(författare)
-
Direct observations of anomalous resistivity and diffusion in collisionless plasma
- 2022
-
Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 13:1
-
Tidskriftsartikel (refereegranskat)abstract
- Coulomb collisions provide plasma resistivity and diffusion but in many low-density astrophysical plasmas such collisions between particles are extremely rare. Scattering of particles by electromagnetic waves can lower the plasma conductivity. Such anomalous resistivity due to wave-particle interactions could be crucial to many processes, including magnetic reconnection. It has been suggested that waves provide both diffusion and resistivity, which can support the reconnection electric field, but this requires direct observation to confirm. Here, we directly quantify anomalous resistivity, viscosity, and cross-field electron diffusion associated with lower hybrid waves using measurements from the four Magnetospheric Multiscale (MMS) spacecraft. We show that anomalous resistivity is approximately balanced by anomalous viscosity, and thus the waves do not contribute to the reconnection electric field. However, the waves do produce an anomalous electron drift and diffusion across the current layer associated with magnetic reconnection. This leads to relaxation of density gradients at timescales of order the ion cyclotron period, and hence modifies the reconnection process. It is suggested that waves can provide both diffusion and resistivity that can potentially support the reconnection electric field in low-density astrophysical plasmas. Here, the authors show, using direct spacecraft measurements, that the waves contribute to anomalous diffusion but do not contribute to the reconnection electric field.
|
|
| 45. |
- Graham, Daniel B., et al.
(författare)
-
Universality of Lower Hybrid Waves at Earth's Magnetopause
- 2019
-
Ingår i: Journal of Geophysical Research - Space Physics. - : John Wiley & Sons. - 2169-9380 .- 2169-9402. ; 124:11, s. 8727-8760
-
Tidskriftsartikel (refereegranskat)abstract
- Waves around the lower hybrid frequency are frequently observed at Earth's magnetopause and readily reach very large amplitudes. Determining the properties of lower hybrid waves is crucial because they are thought to contribute to electron and ion heating, cross‐field particle diffusion, anomalous resistivity, and energy transfer between electrons and ions. All these processes could play an important role in magnetic reconnection at the magnetopause and the evolution of the boundary layer. In this paper, the properties of lower hybrid waves at Earth's magnetopause are investigated using the Magnetospheric Multiscale mission. For the first time, the properties of the waves are investigated using fields and direct particle measurements. The highest‐resolution electron moments resolve the velocity and density fluctuations of lower hybrid waves, confirming that electrons remain approximately frozen in at lower hybrid wave frequencies. Using fields and particle moments, the dispersion relation is constructed and the wave‐normal angle is estimated to be close to 90° to the background magnetic field. The waves are shown to have a finite parallel wave vector, suggesting that they can interact with parallel propagating electrons. The observed wave properties are shown to agree with theoretical predictions, the previously used single‐spacecraft method, and four‐spacecraft timing analyses. These results show that single‐spacecraft methods can accurately determine lower hybrid wave properties.
|
|
| 46. |
- Gutierrez, J. A., et al.
(författare)
-
Polyvascular Disease and Risk of Major Adverse Cardiovascular Events in Peripheral Artery Disease A Secondary Analysis of the EUCLID Trial
- 2018
-
Ingår i: Jama Network Open. - : American Medical Association (AMA). - 2574-3805. ; 1:7
-
Tidskriftsartikel (refereegranskat)abstract
- IMPORTANCE The effect of polyvascular disease on cardiovascular outcomes in the background of peripheral artery disease (PAD) is unclear. OBJECTIVE To determine the risk of ischemic events (both cardiac and limb) among patients with PAD and polyvascular disease. DESIGN, SETTING, AND PARTICIPANTS In this post hoc secondary analysis of the international Examining Use of Ticagrelor in Peripheral Artery Disease (EUCLID) trial, outcomes were compared among 13 885 enrolled patients with PAD alone, PAD + coronary artery disease (CAD), PAD + cerebrovascular disease (CVD), and PAD + CAD + CVD. Adjusted Cox proportional hazards regression models were implemented to determine the risk associated with polyvascular disease and outcomes, and intention-to-treat analysis was performed. The EUCLID trial was conducted from December 31, 2012, to March 7, 2014; the present post hoc analysis was performed from June 1, 2017, to February 5, 2018. INTERVENTIONS EUCLID evaluated ticagrelor vs clopidogrel in preventing major adverse cardiac events (cardiovascular death, myocardial infarction [MI], or ischemic stroke) and major bleeding in patients with PAD. MAIN OUTCOMES AND MEASURES The primary end point was a composite of cardiovascular death, MI, or ischemic stroke. Key secondary end points included the individual components of the primary end point and acute limb ischemia leading to hospitalization, major amputation, and lower-extremity revascularization. The primary end point of Thrombolysis in Myocardial Infarction (TIMI) major bleeding was also evaluated. RESULTS The EUCLID trial randomized 13 885 patients with a median age of 66 years (interquartile range, 60-73 years), of whom 3888 (28.0%) were women. At baseline, 7804 patients (56.2%) had PAD alone; 2639 (19.0%) had PAD + CAD; 2049 (14.8%) had PAD + CVD; and 1393 (10.0%) had PAD + CAD + CVD. Compared with patients with isolated PAD, the adjusted hazard ratios (aHRs) for major adverse cardiac events were 1.34 (95% CI, 1.15-1.57; P < .001) for PAD + CVD, 1.65 (95% CI, 1.43491; P < .001) for PAD + CAD, and 1.99 (95% CI, 1.69-2.34; P < .001)for PAD + CAD + CVD. The aHRs for lower-extremity revascularization were 1.17 (95% CI, 1.03-1.34; P = .01) for PAD + CAD, 1.17 (95% CI, 1.02-1.35; P = .02) for PAD + CVD. and 1.34 (95% CI, 1.15-1.57; P < .001) for PAD + CAD + CVD. Polyvascular disease was not associated with an increased risk of acute limb ischemia (aHR for PAD + CVD, 0.91; 95% CI, 0.62-1.34, P = .63; PAD + CAD, 0.93; 95% CI, 0.64-1.34. P = .69; and PAD + CAD + CVD, 0.98; 95% CI, 0.63-1.53, P = .93), major amputation (aHR for PAD + CVD, 0.83; 95% CI, 0.541.27, P = .40; PAD + CAD, 0.74; 95% CI, 0.47-1.16, P = .19; and PAD + CAD + CVD, 1.12; 95% CI, 0.691.80, P = .65), or TI MI major bleeding (PAD + CVD, 0.98; 0.66-1.44, P = .91; PAD + CAD, 1.04; 0.741.48, P = .81; and PAD + CAD + CVD, 0.96; 95% CI, 0.62-1.51, P = .88). CONCLUSIONS AND RELEVANCE Compared with patients with PAD alone, the risk of major adverse cardiac events and lower-extremity revascularization increased with multiple vascular bed involvement. There was no clear increased risk of bleeding associated with polyvascular disease.
|
|
| 47. |
|
|
| 48. |
- Hess, C. N., et al.
(författare)
-
A Structured Review of Antithrombotic Therapy in Peripheral Artery Disease With a Focus on Revascularization A TASC (InterSociety Consensus for the Management of Peripheral Artery Disease) Initiative
- 2017
-
Ingår i: Circulation. - : Ovid Technologies (Wolters Kluwer Health). - 0009-7322 .- 1524-4539. ; 135:25, s. 2534-2555
-
Tidskriftsartikel (refereegranskat)abstract
- Peripheral artery disease affects >200 million people worldwide and is associated with significant limb and cardiovascular morbidity and mortality. Limb revascularization is recommended to improve function and quality of life for symptomatic patients with peripheral artery disease with intermittent claudication who have not responded to medical treatment. For patients with critical limb ischemia, the goals of revascularization are to relieve pain, help wound healing, and prevent limb loss. The baseline risk of cardiovascular and limb-related events demonstrated among patients with stable peripheral artery disease is elevated after revascularization and related to atherothrombosis and restenosis. Both of these processes involve platelet activation and the coagulation cascade, forming the basis for the use of antiplatelet and anticoagulant therapies to optimize procedural success and reduce postprocedural cardiovascular risk. Unfortunately, few high-quality, randomized data to support use of these therapies after peripheral artery disease revascularization exist, and much of the rationale for the use of antiplatelet agents after endovascular peripheral revascularization is extrapolated from percutaneous coronary intervention literature. Consequently, guideline recommendations for antithrombotic therapy after lower limb revascularization are inconsistent and not always evidence-based. In this context, the purpose of this structured review is to assess the available randomized data for antithrombotic therapy after peripheral arterial revascularization, with a focus on clinical trial design issues that may affect interpretation of study results, and highlight areas that require further investigation.
|
|
| 49. |
- Hess, C. N., et al.
(författare)
-
Acute Limb Ischemia in Peripheral Artery Disease Insights From EUCLID
- 2019
-
Ingår i: Circulation. - : Ovid Technologies (Wolters Kluwer Health). - 0009-7322 .- 1524-4539. ; 140:7, s. 556-565
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Acute limb ischemia (ALI) is an important clinical event and an emerging cardiovascular clinical trial outcome. Risk factors for and outcomes after ALI have not been fully evaluated. Methods: EUCLID (Examining Use of Ticagrelor in Peripheral Artery Disease) randomized patients with peripheral artery disease to ticagrelor versus clopidogrel. Enrollment criteria included an ankle-brachial index <= 0.80 or previous lower extremity revascularization. Patients were grouped according to the primary outcome, postrandomization ALI hospitalization. Baseline factors associated with ALI were identified using Cox proportional hazards modeling. Models with ALI hospitalization as a time-dependent covariate were developed for secondary outcomes of major adverse cardiovascular events (myocardial infarction, cardiovascular death, ischemic stroke), all-cause mortality, and major amputation. Results: Among 13 885 patients, 1.7% (n=232) had 293 ALI hospitalizations (0.8 per 100 patient-years). Patients with versus without ALI were younger and more often had previous peripheral revascularization and lower baseline ankle-brachial index. Treatment during ALI hospitalization included endovascular revascularization (39.2%, n=115), surgical bypass (24.6%, n=72), and major amputation (13.0%, n=38). After multivariable adjustment, any previous peripheral revascularization (Hazard Ratio [HR] 4.7, 95% CI 3.3-6.8, P<0.01), baseline atrial fibrillation (HR 1.8, 95% CI 1.1-3.2, P=0.03), and baseline ankle-brachial index <= 0.60 (HR 1.3 per 0.10 decrease, 95% CI 1.1-1.5, P<0.01) were associated with higher ALI risk. Older age (HR 0.8 per 10-year increase, 95% CI 0.7-1.0, P=0.02) and baseline statin use (HR 0.7, 95% CI 0.5-0.9, P<0.01) were associated with lower risk for ALI. There was no relationship between randomized treatment to ticagrelor or clopidogrel and ALI. Among patients with previous revascularization, surgical versus endovascular procedures performed more than 6 months prior were associated with ALI (adjusted HR 2.63, 95% CI 1.75-3.96). In the overall population, ALI hospitalization was associated with subsequent MACE (adjusted HR 1.4, 95% CI 1.0-2.1, P=0.04), all-cause mortality (adjusted HR 3.3, 95% CI 2.4-4.6, P<0.01), and major amputation (adjusted HR 34.2, 95% CI 9.7-20.8, P<0.01). Conclusions: Previous peripheral revascularization, baseline atrial fibrillation, and lower ankle-brachial index identify peripheral artery disease patients at heightened risk for ALI, an event associated with subsequent cardiovascular and limb-related morbidity and mortality.
|
|
| 50. |
- Jansson, Kjell, et al.
(författare)
-
Human intraperitoneal microdialysis : increased lactate/pyruvate ratio suggests early visceral ischaemia
- 2003
-
Ingår i: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 0036-5521 .- 1502-7708. ; 38:9, s. 1007-1011
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Previous studies suggest that visceral ischaemia precedes shock and multiple organ failure, though methods for studying humans are lacking. We aimed to evaluate intraperitoneal microdialysis, a new technique for detecting splanchnic ischaemia in clinical practice. Methods: Right-sided hemicolectomy was performed in eight patients who were studied by microdialysis postoperatively for glucose, lactate, pyruvate and glycerol levels. Results: Six of the eight patients showed a normal postoperative course and had lactate/pyruvate ratios between 7.1 and 21.7, glucose between 4.5 and 14.3 r mmol/L and glycerol between 10.4 and 296 r 7 mol/L. In one patient, intraperitoneal lactate/pyruvate ratio and glycerol increased and glucose decreased 5 r h before low oxygenation appeared. Another patient exhibited a period of increased lactate/pyruvate ratio before a period of atrial fibrillation. Conclusion: Intraperitoneal microdialysis was performed safely. Two out of the eight patients exhibited changes of metabolic markers followed by clinical symptoms that were probably related to transient visceral ischaemia. Our findings suggest that intraperitoneal microdialysis may become a useful tool for monitoring splanchnic ischaemia in clinical practice.
|
|
