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- Bohgard, Mats, et al.
(author)
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Kontinuerliga tvåfraktionsinsamlare för övervakning av partikulära luftföroreningar i arbetsmiljö
- 1981
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Reports (other academic/artistic)abstract
- Rapporten beskriver prototyper av kontinuerliga tvåfraktionsinsamlare för övervakning av partikulära luftföroreningar i arbetsmiljö som har konstruerats. En prototyp är personburen och ger möjligheter till insamling av två partikelstorleksfraktioner i 18 diskreta intervall. PIXE-metoden (analys med partikelinducerad röntgenstrålning) används för multielementanalys av de erhållna proven. Även med mycket korta insamlingstider, ner till 5 minuter, blir detektionsgränserna för de flesta element av yrkeshygieniskt intresse väsentligt lägre än sina respektive hygieniska gränsvärden. Rapporten inkluderar resultat från en enkel fältmätning som utgör ett exempel på de möjligheter den personburna provtagaren ger för yrkeshygieniska mätningar och undersökningar
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| 6. |
- Nilsson, L., et al.
(author)
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On tensile fracture and wave propagation in granular materials
- 1983
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In: Scandinavian journal of metallurgy. - 0371-0459 .- 1600-0692. ; 12:6, s. 299-301
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Journal article (peer-reviewed)abstract
- In the analysis the material is treated as plastic fracturing. A continuum approach to tensile fracturing is related to fracture mechanical concepts. The rate of strain-softening is obtained from the rate of fracture energy being released. Material anisotropy due to the formation of crack-planes is accounted for. The proposed strain-softening tensile fracturing model is implemented in a finite element program for wave propagation analysis. The strain-softening model is compared to an ideal brittle model in analysis of wave propagation in a concrete rod.
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| 7. |
- Nilsson, Mats Ola, 1946-
(author)
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Latent messenger RNA in dormant Artemia embryos
- 1980
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Doctoral thesis (other academic/artistic)abstract
- This thesis deals with the demonstration and partial characterization of latent messenger RNA in encysted Artemia embryos.RNA was extracted from subcellular fractions of dormant Artemia cysts and tested for template activity in a messenger RNA deficient amino acid incorporating bacterial system. The highest specific activity was found in the relatively small amounts of RNA in the 15 000 g sediment of the cytoplasmic fraction. This sediment was purified by banding in sucrose gradients at a density of 1.17 g/cm3. The purified preparations contained endoplasmic vesicles and mitochondria, which were difficult to separate. Sedimentation analysis of the active RNA showed a heterodisperse distribution of the template activity.The presence of messenger RNA in the purified membrane fraction of dormant embryos was confirmed by hybridization with [3H]poly(U). RNA from the purified membrane fraction had a poly(A) content of 1%. In sucrose gradients the poly(A)-containing (poly(A)+) messenger RNA sedimented at about 14-17S. The estimated chain-length of the poly(A) sequences was 45-65 nucleotides.In polyacrylamide gel electrophoresis the poly(A)+RNA from the purified membrane fraction showed two distinct bands at approximately 3 • 105 and 5 • 105 daltons. In developing embryos (50% emergence) the proportion of the light, 3 • 105 dalton, component was decreased. The nuclear fraction of dormant cysts was devoid of poly(A)+RNA. At 50% emergence the nuclear poly(A)+RNA was characterized by one dominant 5 • 105-dalton component.The presence of mitochondria in the purified membrane fraction made the origin of the poly(A)+RNA questionable. In DNA excess hybridization experiments poly(A)+RNA from the membranes of dormant embryos hybridized to nuclear DNA to the same extent as nuclear poly(A)+RNA from developing embryos. Competition hybridization experiments indicated close homology between the 5 • 105-dalton components in purified membranes and nuclei. It is concluded that the membrane-associated poly(A)+RNA in dormant Artemia embryos is essentially of nuclear origin.
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