| 1. |
- Albert, F, et al.
(författare)
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Laser produced X-ray source in the 10-60 keV range at 1 kHz. Modified irradiation schemes in order to reach medical imaging quality
- 2001
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Ingår i: Journal de Physique IV. - : EDP Sciences. - 1155-4339. ; 11:PR2, s. 429-432
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Tidskriftsartikel (refereegranskat)abstract
- By tightly focusing ultra-short pulses from a Ti:sapphire terawatt laser onto a high-Z metallic target, hard x-ray pulses of short duration are produced. In most of our previous work concerning x-rays, a 150 mJ laser pulse with a 110 A duration has been used. Using mostly tin and tantalum targets, hard x-rays in the 10-60 keV range have been produced and used in differential absorption imaging around the K-alpha absorption edge of a contrast agent and also in imaging employing gated viewing for suppression of scattered radiation. In order to increase the x-ray yield (shortening the acquisition time) an increase in the laser repetition rate is desirable while still staying in the K-alpha energy regime. We have used a I kHz repetition-rate laser delivering 35 fs pulses in order to work towards these goals. We have clear evidence of hard x-ray generation above 30 keV, even for low laser pulse energies. We also studied the effect of a fs prepulse. The medical imaging capability of the source was explored. The use of a prepulse has been optimized in order to improve the image quality as well as the overall x-ray generation yield.
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| 2. |
- Schölin, Anna, et al.
(författare)
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Normal weight promotes remission and low number of islet antibodies prolong the duration of remission in Type 1 diabetes
- 2004
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Ingår i: Diabetic Medicine. - : Wiley. - 0742-3071 .- 1464-5491. ; 21:5, s. 447-455
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Aim To identify clinical, immunological and biochemical factors that predict remission, and its duration in a large cohort of young adults with Type 1 diabetes mellitus (DM).Methods In Sweden, 362 patients (15–34 years), classified as Type 1 DM were included in a prospective, nation-wide population-based study. All patients were followed at local hospitals for examination of HbA1c and insulin dosage over a median period after diagnosis of 5 years. Duration of remission, defined as an insulin maintenance dose ≤ 0.3 U/kg/24 h and HbA1c within the normal range, was analysed in relation to characteristics at diagnosis.Results Remissions were seen in 43% of the patients with a median duration of 8 months (range 1–73). Sixteen per cent had a remission with a duration > 12 months. Among patients with antibodies (ab+), bivariate analysis suggested that adult age, absence of low BMI, high plasma C-peptide concentrations, lack of ketonuria or ketoacidosis at diagnosis and low insulin dose at discharge from hospital were associated with a high possibility of achieving remission. Multiple regression showed that normal weight (BMI of 20–24.9 kg/m2) was the only factor that remained significant for the possibility of entering remission. In survival analysis among ab+ remitters, a low number of islet antibodies, one or two instead of three or four, were associated with a long duration of remissions.Conclusion In islet antibody-positive Type 1 DM, normal body weight was the strongest factor for entering remission, whilst a low number of islet antibodies was of importance for the duration.
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