| 1. |
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| 2. |
- Kraus, Stefan, et al.
(författare)
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Planet Formation Imager (PFI) : Science vision and key requirements
- 2016
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Ingår i: Optical and Infrared Interferometry and Imaging V. - : SPIE. - 9781510601932 ; 9907
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Konferensbidrag (refereegranskat)abstract
- The Planet Formation Imager (PFI) project aims to provide a strong scientific vision for ground-based optical astronomy beyond the upcoming generation of Extremely Large Telescopes. We make the case that a breakthrough in angular resolution imaging capabilities is required in order to unravel the processes involved in planet formation. PFI will be optimised to provide a complete census of the protoplanet population at all stellocentric radii and over the age range from 0.1 to ∼100 Myr. Within this age period, planetary systems undergo dramatic changes and the final architecture of planetary systems is determined. Our goal is to study the planetary birth on the natural spatial scale where the material is assembled, which is the "Hill Sphere" of the forming planet, and to characterise the protoplanetary cores by measuring their masses and physical properties. Our science working group has investigated the observational characteristics of these young protoplanets as well as the migration mechanisms that might alter the system architecture. We simulated the imprints that the planets leave in the disk and study how PFI could revolutionise areas ranging from exoplanet to extragalactic science. In this contribution we outline the key science drivers of PFI and discuss the requirements that will guide the technology choices, the site selection, and potential science/technology tradeoffs.
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| 3. |
- Bajraktari, Gani, et al.
(författare)
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Persistent Ventricular Asynchrony after Coronary Artery Bypass Surgery Predicts Cardiac Events
- 2010
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Ingår i: Echocardiography. - : Wiley. - 0742-2822 .- 1540-8175. ; 27:1, s. 32-37
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Tidskriftsartikel (refereegranskat)abstract
- Aim: The aim of this study was to identify echocardiographic LV systolic and diastolic measurements that predict clinical events post-coronary artery bypass graft (CABG) surgery. Methods: We collected data from 27 patients (age 70 +/- 7 years) who underwent elective CABG, before and within 6 weeks after surgery. LV systolic function was assessed by conventional echocardiographic parameters. A number of LV filling measurements were also made, which included total isovolumic time (t-IVT), Tei index, and restrictive filling pattern. Postoperative cardiac events were death or hospitalization for chest pain, breathlessness, or arrhythmia. Results: Patient's follow-up period was 17 +/- 10 months. Of the 27 patients (age 70 +/- 7 years, 22 male), 10 had postoperative cardiac events. LV ejection fraction (EF) and fractional shortening (FS) were lower (P = 0.01, and P = 0.007, respectively), t-IVT longer (P < 0.001), and Tei index was higher (P < 0.001) preoperatively in patients with events compared to those without. The same differences between groups remained after surgery; EF (P = 0.002), FS (P = 0.002), t-IVT (P < 0.001), and Tei index (P < 0.001). T-IVT was the only preoperative predictor of events (P = 0.038) but its postoperative value as well as that of FS predicted events (P = 0.034, and P = 0.042, respectively). T-IVT of 12.2 s/min and FS of 26% were 80% sensitive and 88% specific for predicting postoperative events. Conclusion: Despite successful surgical revascularization residual impairment of LV systolic function and persistent asynchrony in the form of prolonged t-IVT are associated with postoperative events. Since these abnormalities remained despite full medical therapy, they may thus suggest a need for electrical resynchronization therapy.
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| 4. |
- Bajraktari, Gani, et al.
(författare)
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Prolonged total isovolumic time predicts cardiac events following coronary artery bypass surgery
- 2008
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Ingår i: European Journal of Echocardiography. - : Oxford University Press. - 1525-2167 .- 1532-2114. ; 9:6, s. 779-783
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: Left ventricular (LV) systolic dysfunction may be associated with compromised stroke volume, which may be caused by asynchrony, reflected on the prolongation of isovolumic time (t-IVT). To assess the prognostic role of Doppler echocardiographic measurements in predicting cardiac events after coronary artery bypass grafting (CABG).METHODS AND RESULTS: The study included 74 patients undergoing routine CABG. A pre-CABG Doppler echocardiographic assessment of LV dimensions, filling and ejection was performed and t-IVT was determined as [60 - (total ejection time + total filling time)]. Follow-up period was 18 +/- 12 months. Of the 74 patients (age 65 +/- 16 years, 59 males), 29 underwent hospital admission for a cardiac event or died. There were no differences in age, gender, incidence of previous infarct or mitral regurgitation, LV-EDD (left ventricular end-diastolic dimension), left atrial or right ventricular size in patients with cardiac events compared with those without events. Left ventricular end-systolic dimension (LV-ESD) was greater (4.5 +/- 0.9 vs. 3.9 +/- 0.9 cm, P = 0.003), fractional shortening (FS) was lower (21 +/- 4 vs. 32 +/- 8%), E:A ratio and Tei index were higher (2.1 +/- 0.8 vs. 1.0 +/- 0.6 and 0.9 +/- 0.3 vs. 0.6 +/- 0.3, all P < 0.001), and t-IVT was longer (16 +/- 5 vs.10 +/- 4 s/min, P < 0.001) in patients with events. Multivariate predictors of post-CABG events (odds ratio 95% confidence interval) were low FS [0.66 (0.50-0.87), P < 0.001], high E:A ratio [l4.13 (1.17-14.60), P = 0.028], large LV-ESD [0.19 (0.05-0.84), P = 0.029], and long t-IVT [1.37 (1.02-1.84), P = 0.035].CONCLUSION: Despite satisfactory surgical revascularization, long t-IVT and systolic dysfunction suggest persistent ventricular dyssynchrony that contributes to post-CABG cardiac events. Early assessment of such patients for potential benefit from electrical resynchronization may optimize their cardiac performance and hence clinical outcome.
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| 5. |
- Caliskan, Etem, et al.
(författare)
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Saphenous vein grafts in contemporary coronary artery bypass graft surgery
- 2020
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Ingår i: Nature Reviews Cardiology. - : Nature Publishing Group. - 1759-5002 .- 1759-5010. ; 17:3, s. 155-169
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Forskningsöversikt (refereegranskat)abstract
- Myocardial ischaemia resulting from obstructive coronary artery disease is a major cause of morbidity and mortality in the developed world. Coronary artery bypass graft (CABG) surgery is the gold-standard treatment in many patients with complex multivessel coronary artery disease or left main disease. Despite substantial improvements in the outcome of patients undergoing CABG surgery in the past decade, graft patency remains the 'Achilles' heel' of this procedure. Whereas the use of the left internal mammary artery as a conduit is associated with the highest 10-year patency rate (>90%), saphenous vein grafts - the most commonly used conduit in CABG surgery - fail in 40-50% of treated patients by 10 years after surgery. Vein graft disease (VGD) and failure result from complex pathophysiological processes that can lead to complete occlusion of the graft, affecting long-term clinical outcomes. Optimal harvesting techniques, intraoperative preservation strategies and intraoperative patency control have important roles in the prevention of VGD. In addition, several studies published in the past decade have reported similar mid-term patency rates between vein grafts and arterial grafts when veins are used as a composite graft based on the internal mammary artery. In this Review, we present the latest evidence on the utilization of saphenous vein grafts for CABG surgery and provide an overview of the current practices for the prevention of VGD and vein graft failure.
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| 6. |
- Chuang, Yi De, et al.
(författare)
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Momentum-resolved resonant inelastic soft X-ray scattering (qRIXS) endstation at the ALS
- 2022
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Ingår i: Journal of Electron Spectroscopy and Related Phenomena. - : Elsevier BV. - 0368-2048. ; 257
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Tidskriftsartikel (refereegranskat)abstract
- A momentum resolved resonant inelastic X-ray scattering (qRIXS) experimental station with continuously rotatable spectrometers and parallel detection is designed to operate at different beamlines at synchrotron and free electron laser (FEL) facilities. This endstation, currently located at the Advanced Light Source (ALS), has five emission ports on the experimental chamber for mounting the high-throughput modular soft X-ray spectrometers (MXS) [24]. Coupled to the rotation from the supporting hexapod, the scattered X-rays from 27.5° (forward scattering) to 152.5° (backward scattering) relative to the incident photon beam can be recorded, enabling the momentum-resolved RIXS spectroscopy. The components of this endstation are described in details, and the preliminary RIXS measurements on highly oriented pyrolytic graphite (HOPG) reveal the low energy vibronic excitations from the strong electron-phonon coupling at C K edge around σ* band. The grating upgrade option to enhance the performance at low photon energies is presented and the potential of this spectroscopy is discussed in summary.
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| 7. |
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| 8. |
- Ding, Wen-Hong, et al.
(författare)
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Early and long-term survival after aortic valve replacement in septuagenarians and octogenarians with severe aortic stenosis.
- 2010
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Ingår i: International Journal of Cardiology. - : Elsevier. - 0167-5273 .- 1874-1754. ; 141:1, s. 24-31
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To evaluate the predictors for mortality following aortic valve replacement (AVR) in elderly patients with aortic stenosis (AS).METHODS: 112 consecutive elderly AS patients (aged 77+/-2 years) with AVR between 1998 and 2003 were studied. Clinical and echocardiographic data of LV function were recorded before and 46 months after AVR. Results were compared with 72 younger patients (aged 60+/-1 years). Outcome measures were 30-day and long-term all cause mortalities.RESULTS: Elderly patients had higher NYHA class, more frequent atrial fibrillation, coronary artery disease, emergency operation and use of bioprosthetic valves. They also had shorter E-wave deceleration time (DT) and larger left atria (p<0.05 for all). 30-day mortality was 12% vs 4% (Log Rank x(2)=3.02, p=0.08) and long term mortality was 18% vs 7% (Log Rank x(2)=4.38, p=0.04) in two groups respectively. Age was not related to mortality after adjustment for other variables. Among all variables, anemia (OR 4.20, CI: 1.02-6.86, p=0.04), cardiopulmonary bypass (CPB) time (OR 1.02, CI 1.01-1.04, p<0.01), significant prosthesis patient mismatch (PPM) (OR 5.43, CI 1.04-18.40, p<0.05) were associated with 30-day mortality in elderly patients. Their long-term mortality was related to CBP time (OR 1.02, CI 1.00-1.05, p=0.04), PPM (OR 4.64, CI 1.33-16.11, p=0.02) and raised left atrial pressure: DT (OR 0.94, CI 0.84-0.99, p=0.03) and pulmonary arterial systolic pressure (OR 1.12, CI 1.03-1.19, p<0.001).CONCLUSION: Peri-operative AVR survival is encouraging. While pre-operative anemia and a longer CBP time determine early mortality, long term mortality is related to PPM, LV diastolic dysfunction and secondary pulmonary hypertension.
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| 9. |
- Ding, Wen-hong, et al.
(författare)
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Echocardiographic predictors of left ventricular functional recovery following valve replacement surgery for severe aortic stenosis.
- 2008
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Ingår i: International Journal of Cardiology. - : Elsevier BV. - 0167-5273 .- 1874-1754. ; 128:2, s. 178-84
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: We aimed to identify the most sensitive echocardiographic measurements that predict recovery of left ventricular function following valve replacement surgery in patients with severe aortic stenosis (AS) and LV dysfunction.METHODS: We studied 66 patients (mean age 70+/-2 years, 53 male) who underwent AVR for severe AS with concurrent LV dysfunction between 1998 and 2003 at the Royal Brompton Hospital. Clinical symptoms, co-morbidities and echocardiographic measurements of LV function were recorded before and at a median follow-up of 46 months after AVR. Pre-operative LV systolic dysfunction was defined as LV ejection fraction (EF) <50% and the post-op LV recovery as an increase of EF >10%.RESULTS: Following AVR peak aortic pressure gradient decreased and aortic valve area index increased (64+/-3 to 19+/-1 mm Hg and 0.30+/-0.01 to 0.89+/-0.03 cm(2)/m(2), p<0.001 for both). LV EF increased (from 45+/-1 to 54+/-2%; p<0.001) and the LV dimensions fell (LVEDD index: from 33+/-1 to 30+/-1 mm/m(2); and LVESD index: from 27+/-1 to 20+/-1 mm/m(2); p<0.01 for both). LV diastolic dysfunction improved as evidenced by the fall in E/A ratio (from 2.6+/-0.2 to 1.9+/-0.4) and prolongation of total filling time; (from 29.2+/-0.6 to 31.4+/-0.5 s/min, p=0.01 for both). Among all echocardiographic variables, LV dimensions (LVEDD index, OR 0.70, CI 0.52-0.97, p<0.05; LVESD index, OR 0.57, CI 0.40-0.85, p=0.005) were the two independent predictors of post-operative LV functional recovery on multivariate analysis. A cut off value of pre-operative LVESD index=or<27.5 mm/m(2) was 85% sensitive and 72% specific in predicting intermediate-term recovery of LV function after AVR (AUC, 0.72, p=0.002).CONCLUSION: LV functional recovery was evident in majority of aortic stenotic patients with LV dysfunction after aortic valve replacement. A lower prevalence of LV functional recovery in patients with large pre-operative LV end systolic dimension index might signify the loss of contractile reserve and thus predict post-operative functional recovery.
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| 10. |
- Ding, Wen-Hong, et al.
(författare)
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Predictors of survival after aortic valve replacement in patients with low-flow and high-gradient aortic stenosis
- 2009
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Ingår i: European Journal of Heart Failure. - : Oxford University Press. - 1388-9842 .- 1879-0844. ; 11:9, s. 897-902
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: To identify predictors of survival following aortic valve replacement (AVR) in patients with low-flow and high-gradient aortic stenosis (AS).METHODS AND RESULTS: Eighty-six patients (aged 71 +/- 10 years) with severe AS [aortic valve mean pressure gradient >40 mmHg or valve area <1.0 cm(2)] and left ventricular (LV) dysfunction [ejection fraction (EF) <50%] underwent AVR. Cox proportional hazards were used to identify independent clinical and echocardiographic predictors of mortality. Operative (30-day) mortality was 10%. Peri-operative mortality was associated with lower mean LVEF, higher mitral E:A ratio, peak systolic pulmonary artery pressure (PSPAP), and serum creatinine (by 12%, 2.3, 28 mmHg, and 74 mmol/L, respectively, all P < 0.001), NYHA class III-IV (100 vs. 65%), concomitant CABG (89 vs. 55%), urgent surgery (78 vs. 35%), and longer bypass-time (by 28 min, all P < 0.05). Mortality at 4 years was 17%. Univariate predictors [hazard ratio (HR)] of 4-year mortality were: lower EF (HR 0.68 per % increase, P < 0.001), presence of restrictive LV filling (HR: 3.52, P < 0.001), raised PSPAP (HR: 1.07, P < 0.001), and CABG (HR: 4.93, P = 0.037). However, only low EF (<40%, HR 0.74, P = 0.030), the presence of restrictive filling (HR 1.77, P = 0.033), and raised PSPAP (>45 mmHg, HR 2.71, P = 0.010) remained as independent predictors after multivariate analysis. CONCLUSION: The severity of pre-operative systolic and diastolic LV dysfunction is the major predictor of mortality following AVR for low-flow and high-gradient AS.
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