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- Degerstedt, Oliver, et al.
(författare)
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Quantitative imaging of doxorubicin diffusion and cellular uptake in biomimetic gels with human liver tumor cells
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Novel tumor-on-a-chip approaches are increasingly used to investigate tumor progression and potential treatment options. To improve the effect of any cancer treatment it is important to have an in-depth understanding of drug diffusion, penetration across the tumor extracellular matrix and cellular uptake. In this study, we have developed a miniaturized chip where drug diffusion and cellular uptake in different hydrogel environments can be quantified at high resolution using live imaging. Diffusion of doxorubicin was reduced in a biomimetic hydrogel mimicking tissue properties of cirrhotic liver and early stage hepatocellular carcinoma (362 ± 109 µm2/s) as compared to an agarose gel (571 ± 145 µm2/s, p = 0.0085). The diffusion was further lowered to 164 ± 33 µm2/s (p = 0.0023) by preparing the biomimetic gel in cell media instead of phosphate buffered saline. The addition of liver tumor cells (Huh7 or HepG2) to the gel, at two different densities, did not significantly influence drug diffusion. Clinically relevant and quantifiable doxorubicin concentration gradients (1-20 µM) were established in the chip within one hour. Intracellular increases in doxorubicin fluorescence correlated with decreasing fluorescence of the DNA-binding stain Hoechst 33342, and based on the quantified intracellular uptake of doxorubicin an apparent cell permeability (9.00 ± 0.74 x 10-4 µm/s for HepG2) was determined.
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- Berg, Lotta, et al.
(författare)
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Yttrande från SLUs vetenskapliga råd för djurskydd om hållande av hund och katt
- 2018
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Detta yttrande är skrivet på uppdrag av Jordbruksverket i samband med verkets översyn av föreskrifterna för hund och katt. För att Jordbruksverkets föreskrifter ska vara väl förankrade i den senaste forskningen önskar verket inhämta underlag från det vetenskapliga rådet för djurskydd vid Sveriges lantbruksuniversitet, specifikt gällande områdena rörelsebehov, social kontakt och avvänjning.
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| 5. |
- Bindler, Richard, 1963-, et al.
(författare)
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Reshaping the landscape: mining, metallurgy and a millennium of environmental changes in south-central Sweden
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Before the recognition of emerging environmental issues during the 20th century such as acid rain, mercury pollution, climate change and biodiversity loss, human activities had already significantly altered landscapes around the globe. As elsewhere in Europe, the introduction of agriculture into Sweden during the Bronze and Iron Ages led to changes in forest cover, especially in southern areas, but also more limited impacts in central and northern Sweden along river valleys and coastal areas. In central Sweden the rise and rapid spread of ore mining and metallurgy from the 12th and especially 13th century initiated a widespread reshaping of the landscape named after its mining heritage –Bergslagen (mining laws). This mineral rich 89,000 km2 region encompasses ~5000 metallurgical sites (furnaces, smelters, foundries, forges) and ~10000 mines registered in the Swedish National Antiquities Board’s database.Analyses of >30 lake-sediment records using a combination of geochemical, diatom and pollen analyses, in combination with archaeological and historical records and toponyms, add important details to the early, poorly documented history of mining/metallurgy as well as provide insights into some of the environmental impacts across this large landscape. These impacts included damming of lakes and regulation of watercourses for waterpower, increase in erosion, emission of metals to surface waters and the atmosphere (and leaching from slag piles), decrease in forest cover and changes in water quality. The discontinuous appearance of pollen from cultivated plants (cereals) indicates some limited settlement before the 12th century, but the regular occurrence thereafter of cereal pollen together with a sharp increase in charcoal particles and geochemical evidence of mining/metallurgical activities, indicates mining/metallurgy was a driving force for settlement. Decline in forest cover was gradual from the 13th century, but was more significant from the late 16th century when iron and copper production increased exponentially. The increased demand for charcoal and increased agriculture, including an expansion of summer forest farms, contributed to a reduction in inferred forest cover to 40–80% – as compared to pre-anthropogenic (≤2000 BP) values of 84–95%. From the 16th century charcoal became the limiting resource within Bergslagen and metallurgy expanded to regions adjoining Bergslagen, contributing to a more widespread decline in forest cover also beyond the Bergslagen landscape.In association with the increase in land-use activities and resulting changes in vegetation cover, there was a decline (20–50%) in spectrally inferred lake-water total organic carbon, which we hypothesize resulted from a decreased pool of labile soil carbon. In some lakes closely connected with blast furnaces, where the peasant-miners also lived and farmed, there was an increase in diatom-inferred lake-water pH – as observed previously in SW Sweden in association with Iron Age land use. Only in a suite of lakes in close proximity to the smelting of copper sulfide ores in the surroundings of Falun was there evidence for pre-20th century acidification.While current rates of environmental change may be unprecedented, they build on an already modified landscape. Because pre-industrial conditions, i.e., pre-19th century, are often used as a reference level the scale of current changes may underestimate the full extent of ecosystem and environmental impacts.
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- Gråsjö, Johan, 1962-, et al.
(författare)
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Ion mobility and gel complex structure in dodecyl trimethylammonium/polyacrylate gel complexes
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- In the present study dielectric spectroscopy and small angle x-ray scattering were employed to evaluate temperature dependent ionic mobility and structural features in a dodecyltrimethylammonium/polyacrylate gel complex. A gradually transition of the gel complex from a structure exclusively consisting of discrete micelles arranged on a hexagonal close-packed lattice at 25 °C to a structure mainly consisting of a hexagonal phase of long rod-like micelles at ~ 65 °C was revealed. As well it was found that the mobility of the dodecyltrimethylammonium surfactant ions increased with an increasing fraction of hexagonal phase domains, something which was most likely due to a “residence time-hopping distance” mechanism of monomer ions moving between the micelles. The present findings should be useful for the understanding of the gel structure influence on the mechanisms for surfactant transport and shell formation in surfactant polyion gel complexes.
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