| 1. |
- Bergstrom, H, et al.
(författare)
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Detection of carbon using amplified laser-induced fluorescence
- 1989
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Ingår i: Chemical Physics Letters. - 0009-2614. ; 155, s. 27-31
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Tidskriftsartikel (refereegranskat)abstract
- Radiative lifetimes and stimulated emission have been studied in two-photon-excited carbon atoms. A strong fluorescence enhancement was detected in the direction of the exciting laser beam. Rate equations for the energy levels involved have been calculated in order to obtain number densities from the emitted light. Lifetimes were measured for the 2p3p 3p and 3D states and for the A 3[Pi]g state of the C2 molecule.
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| 2. |
- Bergstrom, H, et al.
(författare)
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Investigations of radiative lifetimes in the 3p 5p configuration of neutral silicon
- 1989
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Ingår i: Zeitschrift für Physik D Atoms, Molecules and Clusters. - 0178-7683. ; 13:1, s. 29-31
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Tidskriftsartikel (refereegranskat)abstract
- Lifetimes for the3S1,3P0, 1, 2 and3D1, 2, 3 states in the 3s23p5p configuration of silicon have been determined using stepwise dye laser excitation and time resolved detection. A comparison is made with theoretical values, calculated using multi-configuration Hartree-Fock wavefunctions. Laser-evaporation was used to produce free silicon atoms by focusing a Nd: YAG laser on a rotating silicon target.
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| 3. |
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| 4. |
- Ayer-LeLievre, C, et al.
(författare)
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Nerve growth factor mRNA and protein in the testis and epididymis of mouse and rat.
- 1988
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - 0027-8424 .- 1091-6490. ; 85:8, s. 2628-32
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Tidskriftsartikel (refereegranskat)abstract
- In situ hybridization using beta-nerve growth factor (NGF) DNA probes was used to demonstrate NGF mRNA in spermatocytes and early spermatids of adult mouse. NGF mRNA-containing cells were also identified in the epithelium of convoluted ducts in mouse corpus epididymidis. Blot-hybridization analysis of RNA prepared from mouse testis and epididymis as well as from rat epididymis confirmed the presence of a 1.3-kilobase (kb) NGF mRNA in these tissues. In the rat testis, however, only a 1.5-kb NGF mRNA was found, corresponding in size to a minor NGF mRNA detected in the rat brain, heart, and epididymis. By using affinity-purified anti-NGF antibodies, NGF-like immunoreactivity was observed in germ cells of rat and mouse testis and in the lumen of epididymis. Extracts of both mouse epididymis and testis stimulated fiber outgrowth in cultured sympathetic ganglia, and the effect was blocked by antibodies to mouse NGF. A two-site enzyme immunoassay showed the presence of 10 and 70 ng of NGF per g of tissue in the mouse testis and epididymis, respectively. Furthermore, RNA blot analysis showed the presence of mRNA for the NGF receptor in mouse testis. These results suggest a nonneurotrophic role for NGF in the male reproductive system, possibly in survival maturation and/or motility of spermatozoa.
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| 5. |
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| 6. |
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| 7. |
- Bergstrom, H, et al.
(författare)
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Two different types of hollow-cathode discharges used for high resolution laser spectroscopy on copper
- 1989
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Ingår i: Zeitschrift für Physik D Atoms, Molecules and Clusters. - 0178-7683. ; 13:3, s. 203-206
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Tidskriftsartikel (refereegranskat)abstract
- Two different techniques, Doppler-free saturation spectroscopy on a hollow-cathode discharge and fluorescence spectroscopy on a collimated atomic beam produced from a hollow-cathode discharge, have been used for high-resolution laser-spectroscopy measurements on the 3d10 4p and 5p states in neutral Copper. The relative merits of the two techniques are discussed.
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| 8. |
- Carlsson, Jan, et al.
(författare)
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Catalase inhibition by sulfide and hydrogen peroxide-induced mutagenicity in Salmonella typhimurium strain TA102
- 1988
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Ingår i: Mutation research. - : Elsevier. - 0027-5107 .- 1873-135X. ; 202:1, s. 59-64
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Tidskriftsartikel (refereegranskat)abstract
- The lethal and mutagenic effects of hydrogen peroxide were studied in exponentially growing cultures of Salmonella typhimurium strain TA102. Exposure of the cultures to non-lethal levels of sodium sulfide significantly increased the lethality and mutagenicity of hydrogen peroxide. The catalase activity was decreased in cells exposed to sodium sulfide, but there were no changes in the cellular levels of superoxide dismutase, glutathione reductase, or NADPH-dependent alkyl hydroperoxide reductase. Hydrogen peroxide-induced mutagenesis and killing of S. typhimurium strain TA102 in the presence of sulfide may in part be explained by an inactivation of catalase by sulfide.
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| 9. |
- Ernfors, P, et al.
(författare)
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Developmental and regional expression of beta-nerve growth factor receptor mRNA in the chick and rat.
- 1988
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Ingår i: Neuron. - 0896-6273 .- 1097-4199. ; 1:10, s. 983-96
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Tidskriftsartikel (refereegranskat)abstract
- Hybridization probes from the transmembrane region of the chick NGF receptor (NGF-R) that show high homology with the rat NGF-R were used to demonstrate an abundant 4.5 kb NGF-R mRNA in the chick embryo at E3.5. The level remained high until E12 but decreased to adult levels by E18. The highest levels at E8 were in spinal cord, bursa of Fabricius, gizzard, femoralis muscle, and skin. In situ hybridization to E7 embryos showed high expression of the NGF-R gene in spinal cord, particularly the lateral motor column, and in dorsal root, sympathetic, and nodose ganglia. NGF-R mRNA expression was observed throughout brain development and in all regions of the adult brain, with high levels in cerebellum and septum. Lymphoid tissues of chick and rat also expressed the receptor. The complex and widespread expression of NGF-R mRNA in areas not known to be NGF targets suggests broader functions for NGF.
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| 10. |
- Granéli, Edna, et al.
(författare)
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Connection between trace metals, chelators and red tide blooms in the Laholm Bay, SE Kattegat - An experimental approach
- 1986
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Ingår i: Marine Environmental Research. - : Elsevier BV. - 0141-1136 .- 1879-0291. ; 18:1, s. 61-78
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Tidskriftsartikel (refereegranskat)abstract
- The influence of the trace metals, copper, aluminum and iron, and of the strong complexing agents, EDTA and NTA, on phytoplankton growth in water from a brackish water bay was investigated through bioassay experiments. A diatom (Skeletonema costatum (Grev.) Cleve) and a dinoflagellate (Prorocentrum minimum (Pav.) J. Schiller) were used as test organisms. The growth of both phytoplankton species was strongly inhibited by copper. This inhibition was generally eliminated by EDTA and NTA. Both phytoplankton species were considerably less inhibited by aluminum than by copper at the same total metal concentration. While S. costatum responded to copper and chelator additions in the same way in sea water samples from different seasons, the growth of P. minimum exhibited pronounced seasonal variation. Other parameters than the values of pCu must be considered in order to account for the experimental results. This work supports the theory that alterations in contents of trace metals and natural chelators in sea water are important factors behind shifts in phytoplankton species composition.
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