| 1. |
- Brändström, U., et al.
(författare)
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Results from the intercalibration of optical low light calibration sources 2011
- 2012
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Ingår i: Geoscientific Instrumentation, Methods and Data Systems. - : Copernicus GmbH. - 2193-0856 .- 2193-0864. ; 1:1, s. 43-51
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Tidskriftsartikel (refereegranskat)abstract
- Following the 38th Annual European Meeting onAtmospheric Studies by Optical Methods in Siuntio in Finland,an intercalibration workshop for optical low light calibrationsources was held in Sodankyl¨a, Finland. The mainpurpose of this workshop was to provide a comparable scalefor absolute measurements of aurora and airglow. All sourcesbrought to the intercalibration workshop were compared tothe Fritz Peak reference source using the Lindau CalibrationPhotometer built by Wilhelm Barke and Hans Lauche in1984. The results were compared to several earlier intercalibrationworkshops. It was found that most sources were fairlystable over time, with errors in the range of 5–25 %. To furthervalidate the results, two sources were also intercalibratedat UNIS, Longyearbyen, Svalbard. Preliminary analysis indicatesagreement with the intercalibration in Sodankyl¨a withinabout 15–25 %.
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| 2. |
- Bukartė, E., et al.
(författare)
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Developing ultrasound optical tomography for deep tissue imaging of the breast
- 2024
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Ingår i: 17th International Workshop on Breast Imaging, IWBI 2024. - 1996-756X .- 0277-786X. - 9781510680203 ; 13174
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Konferensbidrag (refereegranskat)abstract
- Ultrasound Optical Tomography (UOT) combines the high-resolution imaging capability of ultrasound with measurements of light absorption and scattering properties of human tissue. This non-invasive technique could distinguish between cancerous and non-cancerous lesions inside the breast tissue, follow tumor shrinkage during preoperative treatment, or provide information on blood oxygenation levels. Recent measurements of phantoms mimicking the optical properties of breast tissue with various lesions indicated that the technique can probe 50 mm deep through the tissue. This work concentrates on developing the UOT setup in transmission mode and discusses its advantages, limitations, and possible improvements.
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| 3. |
- Chaudhry, N., et al.
(författare)
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Breast cancer diagnosis using extended-wavelength diffuse reflectance spectroscopy : comparing tumor subgroups
- 2024
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Ingår i: 17th International Workshop on Breast Imaging, IWBI 2024. - 1996-756X .- 0277-786X. - 9781510680203 ; 13174
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Konferensbidrag (refereegranskat)abstract
- Optical imaging utilize light to analyze biological tissues in detail, non-invasively and without harmful radiation. Examples include ultrasound optical tomography and photoacoustic imaging; both use a limited number of wavelengths. Diffuse reflectance spectroscopy, another optical technique, covers a continuous wavelength range, but without generating an image. This study focuses on extended-wavelength DRS (450-1550 nm) to compare healthy breast tissue with different subgroups of breast cancer. Analysis of 13 breast specimens with invasive ductal or lobular carcinoma reveals distinct optical profiles in tumor subgroups compared to healthy tissue. However, absorption and scattering patterns are similar among the tumor subgroups.
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| 4. |
- Bargholtz, Chr., et al.
(författare)
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The WASA detector facility at CELSIUS
- 2008
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 594:3, s. 339-350
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Tidskriftsartikel (refereegranskat)abstract
- The WASA 4 pi multidetector system, aimed at investigating light meson production in light ion collisions and eta meson rare decays at the CELSIUS storage ring in Uppsala is presented. A unique feature of the system is the use of hydrogen pellets as internal targets for the first time. A detailed description of the design, together with the anticipated and achieved performance parameters are given. (C) 2008 Elsevier B.V. All rights reserved.
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| 5. |
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| 6. |
- Dahlstrand, U, et al.
(författare)
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Identification of tumor margins using diffuse reflectance spectroscopy with an extended-wavelength spectrum in a porcine model
- 2018
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Ingår i: Skin Research and Technology. - : Wiley. - 0909-752X. ; 24:4, s. 667-671
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: A novel extended-wavelength diffuse reflectance spectroscopy (EWDRS) technique is being developed for future clinical non-invasive tumor margin delineation. In this study, the ability of EWDRS to identify the margins of pigmented skin lesions in an in vivo pig model was evaluated.MATERIALS AND METHODS: Extended-wavelength diffuse reflectance spectroscopy recordings (350-1550 nm) were made on 13 pigmented skin lesions and non-pigmented skin, as a reference. The hand-held probe was swept toward the pigmented area until the signal changed, thus indicating that the margin had been identified. A needle was inserted as a marker, and tissue samples were sent for histological analysis. The distance between the EWDRS-defined border and the histological border was measured by 3 independent examiners.RESULTS: The median difference between the EWDRS-defined border and the histological border was 70 μm toward the pigmented tissue (range: -579 to 538 μm). A Pearson correlation coefficient of .95 was obtained for the examiners.CONCLUSIONS: Extended-wavelength diffuse reflectance spectroscopy can be used in vivo to delineate the border of pigmented skin lesions in a porcine model with high accuracy, indicating that it may be a useful tool for non-invasive tumor margin delineation in the future.
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| 7. |
- Engstrom, L., et al.
(författare)
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A new measurement of the 1s2s2p 4p0-1s2p2 4p transitions in c iv : Wavelengths, fine structure intervals and lifetimes
- 1987
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Ingår i: Physica Scripta. - : IOP Publishing. - 0031-8949 .- 1402-4896. ; 36:2, s. 250-254
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Tidskriftsartikel (refereegranskat)abstract
- The n = 0 transition multiplet connecting the lowest quartet states of doubly excited C IV has been studied by beam-foil spectroscopy. The fine structure splittings obtained for the 1s2s2p 4p0and 1s2p2 4p terms confirm previous experimental results with an improved accuracy. The average transition wavelength = (1344.49 0.04)A is now more precisely determined by about a factor of eight. At the new level of precision this value shows a small but significant deviation from the best theoretical predictions. The lifetimes of the 1s2p2 4p levels have been determined as = (0.71 0.07)ns for 4P5/2 and = (1.66 0.13)ns for 4p3/2. The latter value disagrees with previous experimental results but is in excellent agreement with an isoelectronic trend analysis.
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| 8. |
- Engström, Lars, et al.
(författare)
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Observation of an intensity anomaly in the 3s23p 2P1/2, 3/2-3s3p22S1/2 and 2P1/2 resonance transitions in the Al I isoelectronic sequence
- 1989
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Ingår i: Physica Scripta. - : IOP Publishing. - 0031-8949 .- 1402-4896. ; 39:1, s. 66-69
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Tidskriftsartikel (refereegranskat)abstract
- The intensity ratio of the two fine structure components in the 3s23p 2PJ–3s3p 2S1/2 and 2P1/2 resonance transitions has been measured in Al-like S IV, Cl V, Ar VI and Ti X, using the beam-foil technique. Unexpectedly large deviations from the LS ratios are found, particularly in the 2P–2S case. Although these deviations can be understood qualitatively from theoretical calculations (also reported), large quantitative discrepancies are observed in the beginning of the sequence.
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| 9. |
- Haar, R. R., et al.
(författare)
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On the 3s-3 and 3p-3d transitions in ne-like ni xix
- 1987
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Ingår i: Physica Scripta. - : IOP Publishing. - 0031-8949 .- 1402-4896. ; 35:3, s. 296-299
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Tidskriftsartikel (refereegranskat)abstract
- An experimental and theoretical study has been made of the 3s-3p and 3p-d transitions in Ni XIX. The method of beam-foil spectroscopy, using 30-64 MeV Ni ions from a tandem accelerator, has been combined with theoretical calculations using the multiconfiguration Dirac-Fock (MCDF) program.
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| 10. |
- Hutton, R., et al.
(författare)
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Lifetimes of some low-lying levels in ni xvii
- 1987
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Ingår i: Physica Scripta. - : IOP Publishing. - 0031-8949 .- 1402-4896. ; 35:3, s. 300-302
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Tidskriftsartikel (refereegranskat)abstract
- Using the method of beam-foil spectroscopy we have measured the decay times of several n = 3 terms in Mg-like Ni XVII. By applying an effective method for correction of cascades (ANDC) we obtained reliable lifetimes for the terms 3s3p1P, 3s3p3P, 3p21D and 3p2 3P. The experimental data are in good agreement with recent theoretically predicted values.
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