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| 2. |
- Dahlin, Andreas, et al.
(författare)
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Localized Surface Plasmon Resonance Sensing of Lipid-Membrane-Mediated Biorecognition Events
- 2005
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 1520-5126 .- 0002-7863. ; 127:14, s. 5043-5048
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Tidskriftsartikel (refereegranskat)abstract
- Supported phospholipid bilayers (SPBs) have emerged as important model systems for studies of the natural cell membrane and its components, which are essential for the integrity and function of cells in all living organisms, and also constitute common targets for therapeutic drugs and in disease diagnosis. However, the preferential occurrence of spontaneous SPB formation on silicon-based substrates, but not on bare noble-metal surfaces, has so far excluded the use of the localized surface plasmon resonance (LSPR) sensing principle for studies of lipid-membrane-mediated biorecognition reactions. This is because the LSPR phenomenon is associated with, and strongly confined to, the interfacial region of nanometric noble-metal particles. This problem has been overcome in this study by a self-assembly process utilizing localized rupture of phospholipid vesicles on silicon dioxide in the bottom of nanometric holes in a thin gold film. The hole-induced localization of the LSPR field to the voids of the holes is demonstrated to provide an extension of the LSPR sensing concept to studies of reactions confined exclusively to SPB-patches supported on SiO2. In particular, we emphasize the possibility of performing label-free studies of lipid-membrane-mediated reaction kinetics, including the compatibility of the assay with array-based reading (similar to 7 x 7 mu m(2)) and detection of signals originating from bound protein in the zeptomole regime.
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| 3. |
- Dahlin, T., et al.
(författare)
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Geoelectrical resistivity monitoring for localizing gas at Landfills
- 2009
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Ingår i: Near Surface 2009 : 15th European Meeting of Environmental and Engineering Geophysics - 15th European Meeting of Environmental and Engineering Geophysics. - 9073781728 - 9789073781726
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Konferensbidrag (refereegranskat)abstract
- In order to assess the potential of electrical resistivity for imaging gas migration at landfills, two relatively well-known sites - one bioreactor landfill and a conventional landfill - have been monitored successively. A three-dimensional resistivity image could be constructed every two hour on both sites. Meteorological parameters were monitored at the same time, with one measurement taken every hour. Methane concentration was measured in the air at several occasions, the pore pressure was monitored at two locations and some relative estimations of moisture in the top layer were made at the second site. The results show imperfect but interesting correlations between the different parameters and give a hint of how the method could be refined. The resistivity depends on several parameters, but the areas where the resistivity is most variable seem to be clearly related to higher gas emissions.
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| 6. |
- Karlsson, Per Erik, 1957, et al.
(författare)
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Economic assessment of the negative impacts of ozone on crop yields and forest production. A case study of the estate Ostads Sateri in southwestern Sweden
- 2005
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Ingår i: Ambio. - 0044-7447. ; 34:1, s. 32-40
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Tidskriftsartikel (refereegranskat)abstract
- Ground level ozone concentrations, in combination with the prevailing climate, at the estate Ostads Sateri in southwestern Sweden were estimated to reduce the yield of wheat and potato ranging between 5% and 10%. Occasionally, in years with the highest ozone concentrations and/or climatic conditions favoring high rates of ozone uptake to the leaves, yield loss levels above 10% may occur. Based on simple extrapolation, these ozone-induced reductions of crop yields at Ostads Sateri represent a potential total annual yield loss in Sweden in the range of 24.5 million Euro for wheat and 7.3 million Euro for potato, respectively. A simulation of forest growth at Ostad Sateri predicted that prevailing mean ozone exposure during 1993-2003 had the potential to reduce forest growth by 2.2% and the economic return of forest production by 2.6%. Using this value for extrapolation to the national level, the potential annual economic loss for Sweden due to negative impacts of ozone on forest production would be in the range of 56 million Euro (2004 prices).
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| 9. |
- Arvidsson, M., et al.
(författare)
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Resistivity imaging as a tool for rock quarry planning
- 2007
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Ingår i: Near Surface 2007. - 9781629937960
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Konferensbidrag (refereegranskat)abstract
- In the aggregate industry the use of geophysical measuring is rare. The aim of this project is to investigate how geophysical instruments can be a tool in prospecting for rock quarries, and also how they can be a help in which direction they should expand in. To have control over the quality of the aggregates is important and therefore to know when the rock mass is changing is of interest for the production. Two quarries, with different properties, were investigated with different geophysical methods, of which only the result from the electrical measurement is presented here. The fracture frequency was measured as well for comparison. The depth to the bedrock is visible in the inverted resistivity sections for the two sites, and an estimation of the quantity of the till is possible to make. It is also shown that the fracture frequency affects the resistivity of the bulk mass. The results also show that the resistivity imaging is well suited for detecting anomalies in the rock mass, which might affect the production.
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| 10. |
- Brandt, J., et al.
(författare)
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Acutely-dissociated Schwann cells used in tendon autografts for bridging nerve defects in rats: a new principle for tissue engineering in nerve reconstruction
- 2005
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Ingår i: Scand J Plast Reconstr Surg Hand Surg. - 0284-4311. ; 39:6, s. 321-5
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Tidskriftsartikel (refereegranskat)abstract
- A new method of acute dissociation of Schwann cells was used to study the effect of addition of such cells to a tendon autograft--a recently-described graft material--on peripheral nerve regeneration in rats. Autologous Schwann cells were obtained from enzymatic dissociation of predegenerated nerves. The tendon autografts were supplied with Schwann cells through brief in vitro coincubation. Schwann cell-free tendon autografts were used as controls. Axonal outgrowth was measured immunohistochemically after four, seven, and 10 days. At seven days, outgrowth was significantly longer in the pretreated autografts. The use of acutely-dissociated Schwann cells is a new approach to tissue engineering in nerve reconstruction, and may abolish the need for time-consuming culture of Schwann cells.
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| 11. |
- Dahlin, Anna M, 1979-, et al.
(författare)
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Plasma vitamin B12 concentrations and the risk of colorectal cancer : a nested case-referent study
- 2008
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 32:2, s. 304-314
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Tidskriftsartikel (refereegranskat)abstract
- In this nested case-referent study, we related plasma concentrations of vitamin B12 to the risk of colorectal cancer, taking into consideration prediagnostic plasma folate and total homocysteine concentrations. Subjects were 226 cases and double matched referents from the population-based Northern Sweden Health and Disease Study. Follow-up times from recruitment to diagnosis ranged from 0.1 to 12.7 years, with a median of 4.2 years. Plasma vitamin B12 concentrations were inversely associated with the risk of rectal cancer: univariate odds ratio for the highest versus lowest quintile 0.34 (95% confidence interval (95% CI) 0.13-0.83), p(trend) = 0.004. Risk estimates were attenuated slightly but remained statistically significant after adjustment for body mass index, current smoking, recreational and occupational physical activity, alcohol intake and prediagnostic plasma folate and total homocysteine concentrations: OR 0.30 (95% CI 0.08-0.99), p(trend) = 0.025. The corresponding univariate and fully adjusted odds ratios for colon cancer were 1.25 (CI 0.66-2.36), p(trend) = 0.185 and 1.42 (CI 0.67-3.05), p(trend) = 0.113, respectively. The observed over-risk was attributable to left-sided colon cancer. Interaction analyses including vitamin B12, folate and homocysteine were in line with the results for vitamin B12 alone. In conclusion, these results suggest that increasing levels of plasma vitamin B12, alone or together with other factors involved in one-carbon metabolism, may reduce the risk of rectal cancer, whereas for colon cancer, the association appears to be less clear.
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| 12. |
- Dahlin, Lars, et al.
(författare)
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Functional recovery and mechanisms in end-to-side nerve repair in rats
- 2007
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Ingår i: Acta Neurochirurgica. Supplementum. - Vienna : Springer Vienna. - 0065-1419. ; 100, s. 93-95
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: End-to-side nerve repair is attachment of a single distal nerve segment (recipient nerve) end-to-side to an intact donor nerve when there is a lack of proximal nerve segment after injury. The technique is currently used clinically but the mechanism(s) behind this technique are essentially unknown. METHODS: We have studied end-to-side nerve repair in the forelimb of rats, where a single distal radial nerve or an ulnar or a median, or both, nerves are attached end-to-side to an intact musculocutaneous nerve. We have studied functional recovery, origin of the regenerating axons and cell activation by the end-to-side nerve repair. FINDINGS: Functional recovery occurs after end-to-side nerve repair but is less sufficient than conventional end-to-end nerve repair or a nerve graft procedure. Sensory and motor axons grow from the musculocutaneous nerve out into the attached nerve segment(s). An injury is required to the musculocutaneous nerve to activate sensory and motor neurons as well as Schwann cells in the musculocutaneous nerve for initiation of regeneration. CONCLUSIONS: End-to-side nerve repair may be an alternative method in specific cases of complex nerve injuries to reconstruct nerve trunks when no other repair options are possible. Some functional recovery does occur but regeneration of sensory and motor axons require an injury to the neurons of the donor nerve.
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| 13. |
- Dahlin, Lars, et al.
(författare)
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Schwann cells, acutely dissociated from a predegenerated nerve trunk, can be applied into a matrix used to bridge nerve defects in rats
- 2007
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Ingår i: Acta Neurochirurgica. Supplementum. - 0065-1419. ; 100, s. 57-60
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The gold standard to reconstruct a nerve defect is a conventional autologous nerve graft. There may be a lack of such grafts in severe nerve injuries. Alternatives to autologous nerve grafts are needed. METHODS: We have developed a technique where mainly Schwann cells are acutely dissociated from the ends of the severed nerve trunk after nerve injury. The technique does not require long-term cell culture procedures. The obtained cells, which can be dissociated within a few hours, are applied to a silicone tube or a tendon autograft used to bridge a nerve defect. FINDINGS: Dissociated cells from the ends of the severed nerve ends consist of more than 85% of Schwann cells. The remaining cells are ED1 stained macrophages. The cells survive transfer to a silicone tube or a tendon autograft which bridge the nerve defect. Axons do grow through such a graft filled with dissociated cells. CONCLUSION: Our novel model to obtain mainly Schwann cells by dissociation of the cells from the severed nerve ends after injury and add them to a matrix, thereby creating an artificial nerve graft, may be a new technique with potential clinical application in nerve reconstruction.
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| 23. |
- Owen, Richard, et al.
(författare)
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Alluvial aquifers at geological boundaries: geophysical investigations and groundwater resources
- 2005
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Ingår i: Groundwater and human development. - 9780415364430 ; , s. 233-246
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Bokkapitel (refereegranskat)abstract
- Alluvial channel sands in active ephemeral streams are potentially highly productive aquifers that are normally fully recharged annually. The groundwater resource is constrained by the limited three-dimensional extent of these aquifers. Concepts are developed that propose an increase in alluvial aquifer dimensions at geological boundaries. Multi-electrode resistivity and ground penetrating radar are used to investigate the dimensions of an alluvial channel at a geological boundary with the more resistant lithology upstream. These investigations reveal that alluvial channel fill dimensions are increased in the overlying less-resistant lithology downstream of the boundary. Groundwater flow modelling has been used to determine aquifer potential and identify key fluxes, indicating that significant irrigation potential exists from these aquifers.
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| 24. |
- Sjodahl, P., et al.
(författare)
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Resistivity monitoring for leakage and internal erosion detection at Hallby embankment dam
- 2008
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Ingår i: Journal of Applied Geophysics. - : Elsevier BV. - 0926-9851. ; 65:3-4, s. 155-164
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Tidskriftsartikel (refereegranskat)abstract
- Internal erosion is one of the major reasons for embankment dam failures. Despite this, the knowledge of the temporal development of internal erosion in full scale structures is limited. Detection of internal erosion is complicated using conventional methods, and new or improved methods are appreciated. Hallby was the first Swedish embankment to get a permanently installed monitoring system intended for resistivity measurements. Daily measurements started to take place already in late 1996, which make these long term monitoring data unique. This paper includes examples of long term time series from Hallby along with some evaluation and interpretation techniques used when analysing such monitoring data. Time-lapse inversion was used to focus the variation over time and suppress artefacts due to the resistivity structure. Seasonal resistivity variations inside the dam are obvious. Increasing long term resistivity has been noticed in a particular zone in the left embankment. This zone also exhibits larger seasonal variations relative to other parts of the dam, and the variations are increasing. The observations may relate to an ongoing internal erosion process in the dam. The long term change may be indicative of a change in material properties, and the large and increasing variations may reflect higher and increasing seepage levels. In the years 2004 to 2006 the dam was upgraded and the resistivity system reinstalled. The results indicate that resistivity monitoring may have a chance of detecting development of internal erosion at an early stage. (C) 2008 Published by Elsevier B.V.
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| 26. |
- Thomsen, Niels, et al.
(författare)
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Biopsy of the posterior interosseous nerve: a low morbidity method for assessment of peripheral nerve disorders.
- 2009
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Ingår i: Diabetic Medicine: A journal of the British Diabetic Association. - : Wiley. - 1464-5491. ; 26:1, s. 100-104
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: The sural nerve is the commonest peripheral nerve biopsied to help in the diagnosis of peripheral neuropathy of unknown cause. However, associated complications limit its use. The aim was, as an alternative, to asses biopsy of the terminal branch of the posterior interosseous nerve (PIN) in the forearm. METHODS: PIN pathology was morphometrically quantified in 10 male patients with Type 2 diabetes and compared with six PIN biopsy specimens taken post mortem from male cadavers with no history of neuropathy or trauma. RESULTS: The PIN biopsy procedure provides a long (approximately 3 cm) mono- or bifascicular nerve biopsy with generous epineurial tissue and adjacent vessels. Our results show a significantly lower myelinated fibre density in subjects with diabetes [5782 (3332-9060)/mm(2)] compared with autopsy control material [9256 (6593-12,935)/mm(2), P < 0.007]. No postoperative discomfort or complications were encountered. CONCLUSIONS: A reduction in myelinated fibre density has previously been shown to be a clinically meaningful measure of neuropathy in diabetic patients. We demonstrate similar findings using the PIN biopsy. The PIN biopsy procedure fulfils the criteria for nerve biopsy and was well tolerated by the patients. It may be a possible alternative to sural nerve biopsy to allow for diagnosis of neuropathy.
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