| 11. |
- Burza, Matthias, et al.
(författare)
-
Hollow microspheres as targets for staged laser-driven proton acceleration
- 2011
-
Ingår i: New Journal of Physics. - : Institute of Physics Publishing (IOPP). - 1367-2630. ; 13, s. 013030-
-
Tidskriftsartikel (refereegranskat)abstract
- A coated hollow core microsphere is introduced as a novel targetin ultra-intense laser–matter interaction experiments. In particular, it facilitates staged laser-driven proton acceleration by combining conventional target normal sheath acceleration (TNSA), power recycling of hot laterally spreading electrons and staging in a very simple and cheap target geometry. During TNSA of protons from one area of the sphere surface, laterally spreading hot electrons form a charge wave. Due to the spherical geometry, this wave refocuses on the opposite side of the sphere, where an opening has been laser micromachined.This leads to a strong transient charge separation field being set up there, which can post-accelerate those TNSA protons passing through the hole at the right time. Experimentally, the feasibility of using such targets is demonstrated. A redistribution is encountered in the experimental proton energy spectra, as predicted by particle-in-cell simulations and attributed to transient fields set up by oscillating currents on the sphere surface.
|
|
| 12. |
- Carlström, Mattias, 1941-, et al.
(författare)
-
Dietary nitrate attenuates oxidative stress, prevents cardiac and renal injuries, and reduces blood pressure in salt-induced hypertension
- 2011
-
Ingår i: Cardiovascular Research. - : Oxford University Press (OUP). - 0008-6363 .- 1755-3245. ; 89:3, s. 574-585
-
Tidskriftsartikel (refereegranskat)abstract
- Aims Reduced bioavailability of endogenous nitric oxide (NO) is a central pathophysiological event in hypertension and other cardiovascular diseases. Recently, it was demonstrated that inorganic nitrate from dietary sources is converted in vivo to form nitrite, NO, and other bioactive nitrogen oxides. We tested the hypothesis that dietary inorganic nitrate supplementation may have therapeutic effects in a model of renal and cardiovascular disease. Methods and results Sprague-Dawley rats subjected to unilateral nephrectomy and chronic high-salt diet from 3 weeks of age developed hypertension, cardiac hypertrophy and fibrosis, proteinuria, and histological as well as biochemical signs of renal damage and oxidative stress. Simultaneous nitrate treatment (0.1 or 1 mmol nitrate kg(-1) day(-1)), with the lower dose resembling the nitrate content of a diet rich in vegetables, attenuated hypertension dose-dependently with no signs of tolerance. Nitrate treatment almost completely prevented proteinuria and histological signs of renal injury, and the cardiac hypertrophy and fibrosis were attenuated. Mechanistically, dietary nitrate restored the tissue levels of bioactive nitrogen oxides and reduced the levels of oxidative stress markers in plasma (malondialdehyde) and urine (Class VI F2-isoprostanes and 8-hydroxy-2-deoxyguanosine). In addition, the increased circulating and urinary levels of dimethylarginines (ADMA and SDMA) in the hypertensive rats were normalized by nitrate supplementation. Conclusion Dietary inorganic nitrate is strongly protective in this model of renal and cardiovascular disease. Future studies will reveal if nitrate contributes to the well-known cardioprotective effects of a diet rich in vegetables.
|
|
| 13. |
|
|
| 14. |
|
|
| 15. |
- de Geer, Jakob, et al.
(författare)
-
The efficacy of 2D, non-linear noise reduction filtering in cardiac imaging: a pilot study
- 2011
-
Ingår i: Acta Radiologica. - : Informa Healthcare / Wiley-Blackwell / Royal Society of Medicine Press. - 0284-1851 .- 1600-0455. ; 52:7, s. 716-722
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Computed tomography (CT) is becoming increasingly popular as a non-invasive method for visualizing the coronary arteries but patient radiation doses are still an issue. Postprocessing filters such as 2D adaptive non-linear filters might help to reduce the dose without loss of image quality. less thanbrgreater than less thanbrgreater thanPurpose: To investigate whether the use of a 2D, non-linear adaptive noise reduction filter can improve image quality in cardiac computed tomography angiography (CCTA). less thanbrgreater than less thanbrgreater thanMaterial and Methods: CCTA examinations were performed in 36 clinical patients on a dual source CT using two patient dose levels: maximum dose during diastole and reduced dose (20% of maximum dose) during systole. One full-dose and one reduced-dose image were selected from each of the examinations. The reduced-dose image was duplicated and one copy postprocessed using a 2D non-linear adaptive noise reduction filter, resulting in three images per patient. Image quality was assessed using visual grading with three criteria from the European guidelines for assessment of image quality and two additional criteria regarding the left main artery and the overall image quality. Also, the HU value and its standard deviation were measured in the ascending and descending aorta. Data were analyzed using Visual Grading Regression and paired t-test. less thanbrgreater than less thanbrgreater thanResult: For all five criteria, there was a significant (P andlt; 0.01 or better) improvement in perceived image quality when comparing postprocessed low-dose images with low-dose images without noise reduction. Comparing full dose images with postprocessed low-dose images resulted in a considerably larger, significant (P andlt; 0.001) difference. Also, there was a significant reduction of the standard deviation of the HU values in the ascending and descending aorta when comparing postprocessed low-dose images with low-dose images without postprocessing. less thanbrgreater than less thanbrgreater thanConclusion: Even with an 80% dose reduction, there was a significant improvement in the perceived image quality when using a 2D noise-reduction filter, though not approaching the quality of full-dose images. This indicates that cardiac CT examinations could benefit from noise-reducing postprocessing with 2D non-linear adaptive filters.
|
|
| 16. |
- Dévai, Gergely, et al.
(författare)
-
Efficient Code Generation from the High-level Domain-specific Language Feldspar for DSPs
- 2010
-
Ingår i: ODES-8: 8th Workshop on Optimizations for DSP and Embedded Systems, workshop associated with IEEE/ACM International Symposium on Code Generation and Optimization (CGO).
-
Konferensbidrag (refereegranskat)abstract
- Software for digital signal processors (DSPs) is traditionally highly hardware-dependent and hence porting it to new processors usually requires significant design effort. In this paper we present Feldspar (Functional Embedded Language for DSP and Parallelism), an embedded, high-level, domain-specific language for DSP algorithm design and the compilation techniques we developed for generating C code from specifications written in Feldspar. While Feldspar allows description of algorithms on specification level, we show that with the right set of abstractions and transformations this high level, functional specification can be transformed into C code that is comparable or better than reference, hand-crafted C language implementations. The Feldspar compiler is highly modular and plugin-based, hence future hardware-specific plugins will enable automatic generation of efficient, hardware-specific code. This approach enables the encapsulation of knowledge of hardware completely in the compiler and thus allows description of algorithms in completely hardware-independent, portable manner.
|
|
| 17. |
- Eriksson, Per, et al.
(författare)
-
Non-invasive investigations of potential renal artery stenosis in renal insufficiency
- 2010
-
Ingår i: Nephrology, Dialysis and Transplantation. - : Oxford University Press. - 0931-0509 .- 1460-2385. ; 25:11, s. 3607-3614
-
Tidskriftsartikel (refereegranskat)abstract
- Background. The diagnostic value of non-invasive methods for diagnosing renal artery stenosis in patients with renal insufficiency is incompletely known. Methods. Forty-seven consecutive patients with moderately impaired renal function and a clinical suspicion of renal artery stenosis were investigated with computed tomography angiography (CTA), gadolinium-enhanced magnetic resonance angiography (MRA), contrast-enhanced Doppler ultrasound and captopril renography. The primary reference standard was stenosis reducing the vessel diameter by at least 50% on CTA, and an alternative reference standard (‘morphological and functional stenosis’) was defined as at least 50% diameter reduction on CTA or MRA, combined with a positive finding from ultrasound or captopril renography. Results. The frequency of positive findings, calculated on the basis of individual patients, was 70% for CTA, 60% for MRA, 53% for ultrasound and 30% for captopril renography. Counting kidneys rather than patients, corresponding frequencies were 53%, 41%, 29% and 15%, respectively. In relation to the CTA standard, the sensitivity (and specificity) at the patient level was 0.81 (0.79) for MRA, 0.70 (0.89) for ultrasound and 0.42 (1.00) for captopril renography, and at the kidney level 0.76 (0.82), 0.53 (0.81) and 0.30 (0.86), respectively. Relative to the alternative reference standard, corresponding values at the patient level were 1.00 (0.62) for CTA, 0.90 (0.69) for MRA, 0.91 (1.00) for ultrasound and 0.67 (1.00) for captopril renography, and at the kidney level 0.96 (0.76), 0.85 (0.79), 0.71 (0.97) and 0.50 (0.97), respectively. Conclusions. CTA and MRA are superior to ultrasound and captopril renography at diagnosing morphological stenosis, but ultrasound may be useful as a screening method and captopril renography for verifying renin-dependent hypertension.
|
|
| 18. |
- Gardelli, Viktor, et al.
(författare)
-
Coherentism as a foundation for ethical dialog and evaluation in school : value communication, assessment and mediation
- 2011
-
Ingår i: Educating for complex thinking through philosophical inquiry. - Padova : Liguori. ; , s. 13 s.-
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this paper, we are mainly concerned with coherentism as an approach to ethical dialog in school. We have two different but connected aims with the paper. The first aim is to say something about general philosophical questions relating to coherentism as a theory in metaethics, and especially in relation to value education; the second aim is to explore some possible implications of coherentism as a method in studying the enterprise of discussing ethical issues and questions with children as well as the study of the actual ethical discussion in school. Furthermore, we evaluate the connection between a coherentistic approach to justification and the methodological parts of a Philosophy with Children, or Community of Inquiry, approach to ethics in school. Related to this, we scrutinize what implications this has for evaluating ethical learning within Philosophy with Children, or Community of Inquiry, as well as implications for evaluation of the Philosophy with Children, or Community of Inquiry, approaches as methods for dealing with ethical matters in school.
|
|
| 19. |
- Genoud, Guillaume, et al.
(författare)
-
Active control of the pointing of a multi-terawatt laser.
- 2011
-
Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 1089-7623 .- 0034-6748. ; 82:3
-
Tidskriftsartikel (refereegranskat)abstract
- The beam pointing of a multi-terawatt laser wave laser is stabilized on a millisecond time scale using an active control system. Two piezo mirrors, two position sensing detectors, and a computer based optimization program ensure that both near- and far-field are stable, even during single shot operation. A standard deviation for the distribution of laser shots of 2.6 μ rad is achieved.
|
|
| 20. |
- Gimm, Oliver, et al.
(författare)
-
Dual-Energy Computed Tomography Localizes Ectopic Parathyroid Adenoma
- 2010
-
Ingår i: The Journal of Clinical Endocrinology & Metabolism. - Chevy Chase, MD, United States : The Endocrine Society. - 0021-972X .- 1945-7197. ; 95:7, s. 3092-3093
-
Tidskriftsartikel (refereegranskat)abstract
- Dual-energy computed tomography (DECT) can acquire two datasets showing different attenuation levels allowing collectionof additional information about the elementary chemical compositionof the scanned material. Color can then be assigned accordingto the 80- and 140-kV computed tomography (CT) values to obtaina color-mapped, dual-energy image. DECT has been used extensivelyin our department in postmortem CT with excellent results (1).One of the advantages of DECT is that iodine contrast uptakein soft tissue can be quantified. We were wondering about itsability to localize parathyroid adenomas (PAs).
|
|
