| 1. |
- Griffin, M. J., et al.
(författare)
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The Herschel-SPIRE instrument and its in-flight performance
- 2010
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 518, s. L3-
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Tidskriftsartikel (refereegranskat)abstract
- The Spectral and Photometric Imaging REceiver (SPIRE), is the Herschel Space Observatory`s submillimetre camera and spectrometer. It contains a three-band imaging photometer operating at 250, 350 and 500 mu m, and an imaging Fourier-transform spectrometer (FTS) which covers simultaneously its whole operating range of 194-671 mu m (447-1550 GHz). The SPIRE detectors are arrays of feedhorn-coupled bolometers cooled to 0.3 K. The photometer has a field of view of 4' x 8', observed simultaneously in the three spectral bands. Its main operating mode is scan-mapping, whereby the field of view is scanned across the sky to achieve full spatial sampling and to cover large areas if desired. The spectrometer has an approximately circular field of view with a diameter of 2.6'. The spectral resolution can be adjusted between 1.2 and 25 GHz by changing the stroke length of the FTS scan mirror. Its main operating mode involves a fixed telescope pointing with multiple scans of the FTS mirror to acquire spectral data. For extended source measurements, multiple position offsets are implemented by means of an internal beam steering mirror to achieve the desired spatial sampling and by rastering of the telescope pointing to map areas larger than the field of view. The SPIRE instrument consists of a cold focal plane unit located inside the Herschel cryostat and warm electronics units, located on the spacecraft Service Module, for instrument control and data handling. Science data are transmitted to Earth with no on-board data compression, and processed by automatic pipelines to produce calibrated science products. The in-flight performance of the instrument matches or exceeds predictions based on pre-launch testing and modelling: the photometer sensitivity is comparable to or slightly better than estimated pre-launch, and the spectrometer sensitivity is also better by a factor of 1.5-2.
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| 2. |
- Cherif, M. K., et al.
(författare)
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Fc gamma RIIa Polymorphism and Anti-Malaria-Specific IgG and IgG Subclass Responses in Populations Differing in Susceptibility to Malaria in Burkina Faso
- 2012
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Ingår i: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 75:6, s. 606-613
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Tidskriftsartikel (refereegranskat)abstract
- Fc?RIIa is known to be polymorphic; and certain variants are associated with different susceptibilities to malaria. Studies involving the Fulani ethnic group reported an ethnic difference in Fc?RIIa-R131H genotype frequencies between the Fulani and other sympatric groups. No previous studies have addressed these questions in Burkina Faso. This study aimed to assess the influence of Fc?RIIa-R131H polymorphism on anti-falciparum malaria IgG and IgG subclass responses in the Fulani and the Mossi ethnic groups living in Burkina Faso. Healthy adults more than 20 years old belonging to the Mossi or the Fulani ethnic groups were enrolled for the assessment of selected parasitological, immunological and genetic variables in relation to their susceptibility to malaria. The prevalence of the Plasmodium falciparum infection frequency was relatively low in the Fulani ethnic group compared to the Mossi ethnic group. For all tested antigens, the Fulani had higher antibody levels than the Mossi group. In both ethnic groups, a similar distribution of Fc?RIIa R131H polymorphism was found. Individuals with the R allele of Fc?RIIa had higher antibody levels than those with the H allele. This study confirmed that malaria infection affected less the Fulani group than the Mossi group. Fc?RIIa-R131H allele distribution is similar in both ethnic groups, and higher antibody levels are associated with the Fc?RIIa R allele compared to the H allele.
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| 3. |
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| 4. |
- Fattibene, P, et al.
(författare)
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The 4th international comparison on EPR dosimetry with tooth enamel Part 1: Report on the results
- 2011
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Ingår i: Radiation Measurements. - : Elsevier. - 1350-4487 .- 1879-0925. ; 46:9, s. 765-771
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the results of the 4th International Comparison of in vitro electron paramagnetic resonance dosimetry with tooth enamel, where the performance parameters of tooth enamel dosimetry methods were compared among sixteen laboratories from all over the world. The participating laboratories were asked to determine a calibration curve with a set of tooth enamel powder samples provided by the organizers. Nine molar teeth extracted following medical indication from German donors and collected between 1997 and 2007 were prepared and irradiated at the Helmholtz Zentrum Munchen. Five out of six samples were irradiated at 0.1, 0.2, 0.5, 1.0 and 1.5 Gy air kerma; and one unirradiated sample was kept as control. The doses delivered to the individual samples were unknown to the participants, who were asked to measure each sample nine times, and to report the EPR signal response, the mass of aliquots measured, and the parameters of EPR signal acquisition and signal evaluation. Critical dose and detection limit were calculated by the organizers on the basis of the calibration-curve parameters obtained at every laboratory. For calibration curves obtained by measuring every calibration sample three times, the mean value of the detection limit was 205 mGy, ranging from 56 to 649 mGy. The participants were also invited to provide the signal response and the nominal dose of their current dose calibration curve (wherever available), the critical dose and detection limit of which were also calculated by the organizers.
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| 5. |
- Hedberg, Maria E., et al.
(författare)
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Prevotella jejuni sp. nov., isolated from the small intestine of a child with celiac disease.
- 2013
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Ingår i: International journal of systematic and evolutionary microbiology. - : Microbiology Society. - 1466-5034 .- 1466-5026. ; 63:11, s. 4218-4223
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Tidskriftsartikel (refereegranskat)abstract
- Five obligately anaerobic, Gram-negative, saccharolytic and proteolytic, non-spore-forming bacilli (CD3:27, CD3:28T, CD3:33, CD3:32 and CD3:34) are described. All five strains were isolated from the small intestine of a female child with celiac disease. The cells of the five strains were observed to be short rods or coccoid cells with longer filamentous forms seen sporadically. The organisms produced acetic acid and succinic acid as major metabolic end products. Phylogenetic analysis, based on comparative 16S rRNA gene sequence analysis revealed close relationships between CD3:27, CD3:28T and CD3:33 on one hand, between CD3:32 and P. histicola CCUG 55407T and between CD3:34 and P. melaninogenica CCUG 4944BT on the other. The strains CD3:27, CD3:28T and CD3:33 were clearly different from any other species within the genus Prevotella and most closely related to but distinct from P. melaninogenica. Based on 16S rRNA gene, RNA polymerase β-subunit gene and 60-kDa chaperonin protein subunit gene sequencing, phenotypic, chemical and biochemical properties strains CD3:27, CD3:28T and CD3:33 have been determined to represent a novel species within the genus Prevotella, named Prevotella jejuni sp. nov. Strain CD3:28T (CCUG 60371T = DSM 26989T) is the type strain of the proposed new species. All five strains were able to form homologous aggregates, in which tube-like structures were connecting individual bacteria cells. The five strains were able to bind to human intestinal carcinoma cell lines at 37 °C.
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| 6. |
- Israelsson, Axel
(författare)
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Chewing gum and human hair as retrospective dosimeters
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Retrospective dosimeters are sometimes needed after radiological/nuclear (RN) exposures to determine the doses to individuals. Conventional dosimeters may not be at hand or may not be applicable calling for alternative materials.The possible exposure situations can be divided into external and internal; the radiation field stems either from outside the body or from a source within. This thesis investigates the possibility to use chewing gum and hair as retrospective dosimeters. The chewing gum would be used after an unexpected radiation event of external type whereas human hair is examined after chronic intake of uranium. Chewing gum containing xylitol and sorbitol was analyzed using electron paramagnetic resonance (EPR) and the hair was analyzed by alphaspectrometry following radiochemistry and by synchrotron radiation microbeam x-ray fluorescence (SR μ-XRF).Xylitol and chewing gum (in this particular case, V6) are in the present work found to be valuable dosimeters after unexpected radiation events. The xylitol signal linearity with dose in the interval 0-10 Gy was confirmed (r2=1.00). The doses to the coating of the chewing gums were determined 4-6 days after irradiation with an uncertainty of less than 0.2 Gy (1 SD). Spectral dependence with time after exposure was found, but was, however, minimal between 4-8 days.Hair was evaluated and compared with urine as biodosimeter after ingestion and inhalation intake of uranium. Concentrations of 234U and 238U and their activity ratios were measured in the hair, urine and drinking water sampled from 24 drilled bedrock well water users in Östergötland, Sweden, as well as among 8 workers at a nuclear fuel fabrication factory, Westinghouse Electric Sweden. The results show that there is a stronger correlation between the uranium concentrations in the drinking water of the well water and the users’ hair (r2 = 0.50) than with their urine (r2 = 0.21). There is also a stronger correlation between the 234U/238U activity ratios of water and hair (r2 = 0.91) than between water and urine (r2 = 0.56). The individual absorbed fraction of uranium, the ƒ value, calculated as the ratio between the excreted amount of uranium in urine and hair per day and the daily drinking water intake of uranium stretched from 0.002 to 0.10 with a median of 0.023. The uranium concentrations of the fuel factory workers’ hair and urine were also obtained as well as that of personal air sampler (PAS) filters for the determination of inhaled uranium activity. A large day-to-day variation (7-70 Bq d-1) of the inhaled 234U activity was seen over a 6 week period. Over a 12 week period the 234U activity concentration in urine was similarly seen to vary from 2 to 50 mBq kg-1. Four hair samples from the same subject and period showed less variation (100-240 mBq g-1). The uranium inhalation to urine and hair factors finh,u and finh,h were found to be 0.0014 and 0.0002 respectively given by calculations based on the measured PAS, urine and hair data from two individuals. The SR μ-XRF measurements showed that uranium is present in an outer layer of the hair shaft, about 10-15 μm wide. The measurements also revealed particles containing uranium being present on the surface of unwashed hair shafts. However, the washed hair shafts showed few, if any, particles.This thesis concludes that chewing gum and hair can be used as retrospective dosimeters after external radiation and after intake of uranium respectively.
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