| 1. |
- Fairweather-Tait, S, et al.
(författare)
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The usefulness of in vitro models to predict the bioavailability of iron and zinc: A consensus statement from the HarvestPlus Expert Consultation
- 2005
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Ingår i: International Journal for Vitamin and Nutrition Research. - : Hogrefe Publishing Group. - 0300-9831 .- 1664-2821. ; 75:6, s. 371-374
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Tidskriftsartikel (refereegranskat)abstract
- A combination of dietary and host-related factors determines iron and zinc absorption, and several in vitro methods have been developed as preliminary screening tools for assessing bioavailability. An expert committee has reviewed evidence for their usefulness and reached a consensus. Dialyzability (with and without simulated digestion) gives some useful information but cannot predict the correct magnitude of response and may sometimes predict the wrong direction of response. Caco-2 cell systems (with and without simulated digestion) have been developed for iron availability, but the magnitude of different effects does not always agree with results obtained in human volunteers, and the data for zinc are too limited to draw conclusions about the validity of the method. Caco-2 methodologies vary significantly between laboratories and require experienced technicians and good quality cell culture facilities to obtain reproducible results. Algorithms can provide semi-quantitative information enabling diets to be classified as high, moderate, or low bioavailability. While in vitro methods can be used to generate ideas and develop hypotheses, they cannot be used alone for important decisions concerning; food fortification policy, selection of varieties for plant breeding programs, or for new product development in the food industry. Ultimately human studies are required for such determinations.
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| 2. |
- Amanullah, Rahman, et al.
(författare)
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Diversity in extinction laws of Type Ia supernovae measured between 0.2 and 2 μm
- 2015
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 453:3, s. 3300-3328
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Tidskriftsartikel (refereegranskat)abstract
- We present ultraviolet (UV) observations of six nearby Type Ia supernovae (SNe Ia) obtained with the Hubble Space Telescope, three of which were also observed in the near-IR (NIR) with Wide-Field Camera 3. UV observations with the Swift satellite, as well as ground-based optical and NIR data provide complementary information. The combined data set covers the wavelength range 0.2-2 mu m. By also including archival data of SN 2014J, we analyse a sample spanning observed colour excesses up to E(B - V) = 1.4 mag. We study the wavelength-dependent extinction of each individual SN and find a diversity of reddening laws when characterized by the total-to-selective extinction R-V. In particular, we note that for the two SNe with E(B - V) greater than or similar to 1 mag, for which the colour excess is dominated by dust extinction, we find R-V = 1.4 +/- 0.1 and R-V = 2.8 +/- 0.1. Adding UV photometry reduces the uncertainty of fitted R-V by similar to 50 per cent allowing us to also measure R-V of individual low-extinction objects which point to a similar diversity, currently not accounted for in the analyses when SNe Ia are used for studying the expansion history of the Universe.
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| 3. |
- Bood, Mattias, et al.
(författare)
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Pentacyclic adenine: a versatile and exceptionally bright fluorescent DNA base analogue
- 2018
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Ingår i: Chemical Science. - : Royal Society of Chemistry (RSC). - 2041-6520 .- 2041-6539. ; 9:14, s. 3494-3502
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Tidskriftsartikel (refereegranskat)abstract
- Emissive base analogs are powerful tools for probing nucleic acids at the molecular level. Herein we describe the development and thorough characterization of pentacyclic adenine (pA), a versatile base analog with exceptional fluorescence properties. When incorporated into DNA, pA pairs selectively with thymine without perturbing the B-form structure and is among the brightest nucleobase analogs reported so far. Together with the recently established base analog acceptor qAnitro, pA allows accurate distance and orientation determination via Forster resonance energy transfer (FRET) measurements. The high brightness at emission wavelengths above 400 nm also makes it suitable for fluorescence microscopy, as demonstrated by imaging of single liposomal constructs coated with cholesterolanchored pA-dsDNA, using total internal reflection fluorescence microscopy. Finally, pA is also highly promising for two-photon excitation at 780 nm, with a brightness (5.3 GM) that is unprecedented for a base analog.
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| 4. |
- Dumat, Blaise, 1984, et al.
(författare)
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Second-Generation Fluorescent Quadracyclic Adenine Analogues: Environment-Responsive Probes with Enhanced Brightness
- 2015
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Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 21:10, s. 4039-4048
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Tidskriftsartikel (refereegranskat)abstract
- Fluorescent base analogues comprise a group of increasingly important molecules for the investigation of nucleic acid structure, dynamics, and interactions with other molecules. Herein, we report on the quantum chemical calculation aided design, synthesis, and characterization of four new putative quadracyclic adenine analogues. The compounds were efficiently synthesized from a common intermediate through a two-step pathway with the Suzuki-Miyaura coupling as the key step. Two of the compounds, qAN1 and qAN4, display brightnesses (εΦF) of 1700 and 2300, respectively, in water and behave as wavelength-ratiometric pH probes under acidic conditions. The other two, qAN2 and qAN3, display lower brightnesses but exhibit polarity-sensitive dual-band emissions that could prove useful to investigate DNA structural changes induced by DNA-protein or -drug interactions. The four qANs are very promising microenvironment-sensitive fluorescent adenine analogues that display considerable brightness for such compounds. Polarity and pH probes: 2-Aminopurine has long been the standard for fluorescent base analogues. Four new fluorescent probes suitable for the replacement of adenine in nucleic acids are presented. Based on their high structural similarity to their parent compound, quadracyclic adenine, they have the potential to be excellent A analogues. Their improved photophysical properties also suggest that they could be significantly brighter than 2-aminopurine inside nucleic acid systems (see figure; ΦF: fluorescence quantum yield).
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| 5. |
- Eriksson, Leif, 1970, et al.
(författare)
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ALOS PALSAR calibration and validation activities in Sweden
- 2008
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Ingår i: Proceedings of The First Joint PI Symposium of ALOS Data Nodes for ALOS Science Program in Kyoto, Kyoto, Japan, 19 - 23 November, 2007. - 1349-113X. - 9784906653041 ; JAXA-SP-07-012
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 6. |
- Eriksson, Leif, 1970, et al.
(författare)
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ALOS PALSAR Calibration and Validation Results from Sweden
- 2007
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Ingår i: IEEE Geoscience and Remote Sensing Symposium (IGARSS 2007), Barcelona, Spain, July 23-27, 2007. ; DOI: 10.1109/IGARSS.2007.4423115, s. 1589-1592
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In 2006 calibration activities for ALOS PALSAR wereconducted in Sweden. Four five-metre trihedral corner reflectorsand three smaller dihedral reflectors were deployed and operatedduring eight months. 23 PALSAR scenes were acquired over thecalibration site allowing an evaluation of the quality and temporalstability of the data. Results show that the co-polarized datahave been stable during the whole calibration period with variationsin the trihedral responses lower than 0.7 dB. The measuredresolution in azimuth was 4.4 m and in slant range 4.7 m forsingle polarization images and 9.5 m for polarimetric data. Forthe cross-polarized data large variations in the dihedral responseswere found. It is assumed that this is caused by a larger sensitivityto pointing errors. For the polarimetric data, estimation ofFaraday rotation gave values ranging from 0.1º to 3º.
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| 7. |
- Eriksson, Leif, 1970, et al.
(författare)
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Stem volume estimation for boreal forest using ALOS PALSAR
- 2007
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Ingår i: 5th International Symposium on Retrieval of Bio- and Geophysical Parameters from SAR Data for Land Applications, Bari, Italy, September 25-28, 2007, ESA, Istituto di Studi sui Sistemi Intelligenti per l´Automazione. ; , s. CD-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- An evaluation of ALOS PALSAR data for standwise forest stem volume estimation has been performed at a Swedish test site. The site is dominated by coniferous tree species. SAR data from three operational PALSAR modes, including single, dual and quad polarization, have been analyzed. In total, images from 18 different dates were included. Altogether, 56 forest stands with stem volume in the range of 45-650 m3 ha-1 (average 325 m3 ha-1) were analyzed by relating backscatter intensity to field data. The estimation accuracy of stem volume at stand level was calculated in terms of root mean square error (RMSE). For the best case investigated an RMSE of 30% was obtained for one of the single polarization images acquired in the winter season. In this case no saturation was observed for high stem volumes. The corresponding RMSEs for the dual and quad polarization images were between 62%, and 81%. The better results for single polarization might be explained by particularly favourable weather conditions at image acquisition. An extended evaluation will be performed to verify the cause.
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| 8. |
- Fransson, J.E.S., et al.
(författare)
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Detection of clear-cuts using ALOS PALSAR satellite images
- 2008
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Ingår i: Proceedings of the European Conference on Synthetic Aperture Radar, EUSAR. - 2197-4403. ; 1-4
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Konferensbidrag (refereegranskat)abstract
- The objective of this study is to make a first evaluation of the possibilities to detect forest clear-cuts using high-resolution ALOS PALSAR FBD (Fine Beam Dual polarization) satellite images. New operational applications for mapping of changes in forest cover are of interest for government authorities in Sweden and in other countries with similar needs. The study was conducted in southern Sweden and included seven old coniferous stands located on flat terrain. Three of the stands were clear-felled and the remaining stands were left untreated for reference. Altogether, six PALSAR FBD images (look angle 34.3°, HH- and HV-polarization) acquired during the summer and fall seasons were analyzed. The difference in backscattering coefficient between the reference and the clear-felled stands was on average 2.4 dB and 2.9 dB for the HH- and HV-polarization, respectively. When comparing the backscattering coefficient before and after clear-felling the drop was found to be 1.7 dB and 2.3 dB for the HH- and HV-polarization, respectively.
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| 9. |
- Fransson, J.E.S., et al.
(författare)
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Detection of forest changes using ALOS PALSAR satellite images
- 2007
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Ingår i: IEEE Geoscience and Remote Sensing Symposium (IGARSS 2007), Barcelona, Spain, July 23-27, 2007. ; DOI: 10.1109/IGARSS.2007.4423308, s. 2330-2333
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A controlled experiment has been performed to quantify the ability to detect clear-cuts using ALOS PALSAR data. The experiment consisted of 8 old spruce dominated stands with a size of about 1.5 ha, located at a test site in southern Sweden. Four of the stands were clear-felled and the remaining stands were left untreated for reference. A time series of PALSAR images were acquired prior to, during, and after treatment, including 7 Fine Beam Single polarization (FBS, look angle 34.3°, HH-polarization) SAR images. The results clearly show that the clear-felled stands could be separated from the reference stands. The drop in backscattering coefficient between the reference and the clear-felled stands was on average 2.1 dB. This implies that ALOS PALSAR data potentially can be used for large-scale mapping of changes in forest cover.
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| 10. |
- Fransson, J.E.S., et al.
(författare)
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Mapping of Wind-Thrown Forests Using VHF/UHF SAR Images
- 2007
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Ingår i: IEEE 2007 International Geoscience and Remote Sensing Symposium (IGARSS 2007), Barcelona, Spain, July 23-27 2007. ; DOI: 10.1109/IGARSS.2007.4423313, s. 2350-2353
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- SAR images from the Swedish airborne CARABAS-II and LORA systems have been visually analyzed over simulated wind-thrown forest at both single tree and stand level. In ideal conditions, the results show that LORA is more accurate than CARABAS-II at detecting wind-thrown trees, regardless of tree size and direction of the fallen trees relative to flight heading. Furthermore, the visible single trees in the LORA images appeared more distinct than in the CARABAS-II images, which could be explained by the high resolution in the LORA images. Based on visual interpretation, it is likely that the detection of wind-thrown forests could be improved using VHF/UHF SAR images acquired both prior to and after a storm event.
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