SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "LAR1:lu ;pers:(Andersson Engels Stefan)"

Sökning: LAR1:lu > Andersson Engels Stefan

Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Abrahamsson, Christoffer, et al. (författare)
  • Scatter correction of transmission near-infrared spectra by photon migration data: Quantitative analysis of solids
  • 2005
  • Ingår i: Applied spectroscopy. - Society for applied spectroscopy. - 0003-7028. ; 59:11, s. 1381-1387
  • Tidskriftsartikel (refereegranskat)abstract
    • The scope of this work is a new methodology to correct conventional near-infrared (NIR) data for scattering effects. The technique aims at measuring the absorption coefficient of the samples rather than the total attenuation measured in conventional NIR spectroscopy. The main advantage of this is that the absorption coefficient is independent of the path length of the light inside the sample and therefore independent of the scattering effects. The method is based on time-resolved spectroscopy and modeling of light transport by diffusion theory. This provides an independent measure of the scattering properties of the samples and therefore of the path length of light. This yields a clear advantage over other preprocessing techniques, where scattering effects are estimated and corrected for by using the shape of the measured spectrum only. Partial least squares (PLS) calibration models show that, by using the proposed evaluation scheme, the predictive ability is improved by 50% as compared to a model based on conventional NIR data alone. The method also makes it possible to predict the concentration of active substance in samples with other physical properties than the samples included in the calibration model.
2.
  • Abrahamsson, Christoffer, et al. (författare)
  • Scatter correction of transmission NIR spectra by photon migration data - Quantitative analysis of solids
  • 2005
  • Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - International Society for Optical Engineering. - 0277-786X. ; 6009, s. 60090A-60090A
  • Konferensbidrag (refereegranskat)abstract
    • The scope of this presentation is a new methodology to correct conventional NIR data for scattering effects. The technique aims at measuring the absorption coefficient of the samples rather than the total attenuation, measured by conventional NIR spectroscopy. The main advantage of this is that the absorption coefficient is independent of the path length of the light inside the sample, and therefore independent of the scattering effects. The measurements in this work were made using a novel system for time-resolved measurements, based on short light continuum pulses generated in an index-guided crystal fibre and a spectrometer-equipped streak camera. The system enables spectral recordings in the wavelength range 500 - 1200 nm with a spectral resolution of 5 nm and a temporal resolution of 30 ps. The evaluation scheme is based on modeling of light transport by diffusion theory, that provides an independent measure of the scattering properties of the samples, that later is used to correct conventional NIR data. This yields a clear advantage over other pre-processing techniques, where scattering effects are estimated and corrected for by using the shape of the measured spectrum only. PLS calibration models shows that, by using the proposed evaluation scheme, the predictive ability is improved by 50% as compared to models based on conventional NIR data. The method also makes it possible to predict the concentration of active substance in samples with physical properties different from those of the samples included in the calibration model.
  •  
3.
  • Abrahamsson, Christoffer, et al. (författare)
  • Time and wavelength resolved spectroscopy of turbid media using light continuum generated in a crystal fiber
  • 2004
  • Ingår i: Optics Express. - Optical Soc. America. - 1094-4087. ; 12:17, s. 4103-4112
  • Tidskriftsartikel (refereegranskat)abstract
    • We report a novel system for time-resolved diffuse remission spectral measurements, based on short light continuum pulses generated in an index-guided crystal fiber, and a spectrometer-equipped streak camera. The system enables spectral recordings of absorption and reduced scattering coefficients of turbid media in the wavelength range 500 - 1200 nm with a spectral resolution of 5 nm and a temporal resolution of 30 ps. The optical properties are calculated by fitting the solution of the diffusion equation to the time-dispersion curve at each wavelength. Example measurements are presented from an apple, a finger and a pharmaceutical tablet. (C) 2004 Optical Society of America.
4.
  • Abrahamsson, Christoffer, et al. (författare)
  • Time-resolved NIR spectroscopy for quantitative analysis of intact pharmaceutical tablets
  • 2005
  • Ingår i: Analytical Chemistry. - American Chemical Society. - 0003-2700. ; 77:4, s. 1055-1059
  • Tidskriftsartikel (refereegranskat)abstract
    • Near-infrared (NIR) spectroscopy is a useful technique for quantitative measurements of intact tablets, but it suffers from limitations due to the fact that changes in the physical properties of a sample strongly affect the recorded spectrum. In this work, time-resolved transmission NIR spectroscopy was utilized to conduct quantitative measurements of intact tablets. The technique enables separation of the absorption properties of the sample from the scattering properties and can therefore handle changes of the physical parameters of the samples in a better way than conventional NIR transmission spectroscopy. The experiments were conducted using a pulsed Ti:sapphire laser coupled into a nonlinear photonic crystal fiber as light source. The light transmitted through the sample was measured by a time-resolving streak camera. A comparison of the results from the time-resolved technique with the results from conventional transmission NIR spectroscopy was made using tablets containing different concentrations of iron oxide and manufactured with different thicknesses. A PLS model made with data from the time-resolved technique predicted samples 5 times better than a PLS model made data from the conventional NIR transmission technique. Furthermore, an improvement to predict samples with physical properties outside those included in the calibration set was demonstrated.
  •  
5.
  •  
6.
  • af Klinteberg, C, et al. (författare)
  • Compact medical fluorosensor for minimally invasive tissue characterization
  • 2005
  • Ingår i: Review of Scientific Instruments. - American Institute of Physics. - 0034-6748. ; 76:3
  • Tidskriftsartikel (refereegranskat)abstract
    • A compact fiber-optic point-measuring fluorosensor fully adapted to clinical studies is described. The system can use two excitation wavelengths, 337 and 405 nm, obtained from a nitrogen laser directly, or after dye laser conversion, respectively. The image intensifier used in the spectrometer can be gated with a variable time delay, allowing also time-resolved spectra to be extracted, with a time resolution of about 4 ns. Moreover, diffusely scattered white light can be spectrally recorded. The system is fully computer controlled enabling short recording times in clinical application, which are illustrated.
7.
8.
9.
10.
  • af Klinteberg, C, et al. (författare)
  • In vivo absorption spectroscopy of tumor sensitizers with femtosecond white light
  • 2005
  • Ingår i: APPLIED OPTICS. - Optical Society of America. - 0003-6935. ; 44:11, s. 2213-2220
  • Tidskriftsartikel (refereegranskat)abstract
    • A system based on a femtosecond white-light continuum and a streak camera was used for recordings of the in vivo absorption spectra of the tumor-seeking agent disulphonated aluminum phthalocyanine. Measurements for different drug doses were performed on tumor tissue (muscle-implanted adenocarcinoma) and normal muscle tissue in rats. It was found that the shape of the spectrum is tissue dependent. The peak of the absorption spectrum is blueshifted in tumor tissue as compared with the muscle. Thus the contrast in the drug-related absorption can be altered by up to a factor of 2 from the primary drug molecular-concentration contrast between normal muscle and tumor by the proper selection of the illumination wavelength.
Skapa referenser, mejla, bekava och länka
Åtkomst
fritt online (153)
Typ av publikation
tidskriftsartikel (176)
konferensbidrag (70)
rapport (6)
bokkapitel (4)
forskningsöversikt (3)
annan publikation (1)
visa fler...
visa färre...
Typ av innehåll
refereegranskat (240)
övrigt vetenskapligt (20)
Författare/redaktör
Svanberg, Sune (108)
Svanberg, Katarina (94)
Johansson, Jonas (30)
Bendsöe, Niels (30)
Berg, R (25)
visa fler...
Wang, I (23)
Swartling, Johannes (21)
Svensson, Tomas (20)
Axelsson, Johan (19)
Xu, Can (17)
Johansson, Ann (17)
Svenmarker, Pontus (15)
Svensson, Jenny (15)
af Klinteberg, C (14)
Stenram, U (14)
Pifferi, A (13)
Pålsson, Sara (13)
Soto Thompson, Marce ... (13)
Johansson, Thomas (11)
Katzir, A (11)
Liu, Haichun (10)
Cubeddu, R (9)
Sturesson, C, (9)
Xie, Haiyan (9)
Stenram, Unne (8)
Alerstam, Erik (8)
Somesfalean, Gabriel (8)
Jarlman, O (8)
Liu, D. L (8)
Abrahamsson, Christo ... (7)
Taroni, P (7)
Khoptyar, Dmitry (7)
Andersen, PE (7)
Berg, Roger (6)
Lindquist, C (6)
Wårdell, Karin, (6)
Montan, Sune (6)
Nilsson, A. M. K. (6)
Karlsson, Anders (5)
Folestad, S (5)
Folestad, Staffan (5)
Andersen, Peter (5)
Andersen, Peter E. (5)
Rokahr, I (5)
Lundin, Patrik (5)
Wardell, K. (5)
Dam, J. S (5)
Thrane, L (5)
Trebst, Tilmann (5)
visa färre...
Lärosäte
Lunds universitet (260)
Linköpings universitet (8)
Kungliga Tekniska Högskolan (1)
Umeå universitet (1)
Göteborgs universitet (1)
Uppsala universitet (1)
Språk
Engelska (260)
Ämne (HSV)
Medicin och hälsovetenskap (1)

År

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy