| 1. |
- Ubhayasekera, Sarojini J. K. A., et al.
(författare)
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Assessment of Sterol Oxidation in Oils Recovered from Exhausted Bleaching Earth by Coupled Capillary Column GC and GC–MS Methods
- 2012
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Ingår i: Journal of the American Oil Chemists Society. - : Wiley. - 0003-021X .- 1558-9331. ; 89:8, s. 1427-1433
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Tidskriftsartikel (refereegranskat)abstract
- Cholesterol and phytosterols are generally present in foods at ppm levels and they can generate many oxidation products, i.e. oxysterols. The oxysterols comprise only a small percentage of unoxidized sterols. Reliable quantitative data on these compounds requires reasonably good separation by capillary column GC. The present study attempts to overcome the difficulties involved in separating many common oxysterols generated from cholesterol, brassicasterol, campesterol, stigmasterol, and sitosterol by coupling two high-resolution GC capillary columns. The columns, DB-17MS and DB-35MS, were coupled separately to a DB-5MS column. Total separation time of the authentic samples of oxysterols was 41 min for the DB-35MS/DB-5MS and 44 min for the DB-17MS/DB-5MS coupled columns. Two oil samples EBE1 and EBE2 extracted from exhausted bleaching earth collected from Europe were analyzed for oxysterol content by using these column combination systems. Both systems showed similar quantitative results; the total levels of oxysterols in these samples ranged from 2 to 3 mg/100 g. The prominent oxysterols were as follows: 7α-hydroxysterols (0.29–0.49 mg/100 g), 7β-hydroxysterols (0.13–0.68 mg/100 g) and 7-ketosterols (0.63–0.69 mg/100 g).
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| 2. |
- Höglund, Odd, et al.
(författare)
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A new resorbable device for ligation of blood vessels - A pilot study
- 2011
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Ingår i: Acta Veterinaria Scandinavica. - : Springer Science and Business Media LLC. - 0044-605X .- 1751-0147. ; 53, s. 47-
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Tidskriftsartikel (refereegranskat)abstract
- Background: During surgery, controlled haemostasis to prevent blood loss is vital for a successful outcome. It can be difficult to ligate vessels located deep in the abdomen. A device that is easy to use and enables secure ligatures could be beneficial. Cable ties made of nylon have been used for ligation but the non-resorbable material caused tissue reactions. The objective of this study was to use a resorbable material to construct a device with a self-locking mechanism and to test its mechanical strength and ligation efficiency. Methods: The device was manufactured by injection moulding of polydioxanone, a resorbable polymer used for suture materials. Polydioxanone with inherent viscosities of 1.9 dL/g and 1.3 dL/g were tested. The device consisted of a perforated flexible band which could be pulled through a case with a locking mechanism. After a first version of the device had been tested, some improvements were made. The locking case was downsized, corners were rounded off, the band was made thicker and the mould was redesigned to produce longer devices. Tensile tests were performed with the second version. The first version of the device was used to ligate the ovarian pedicle in a euthanized dog and to test echogenicity of the device with ultrasound. Compression of vessels of the ovarian pedicle was examined by histology. Both versions of the device were tested for haemostasis of and tissue grip on renal arteries in six anaesthetised pigs. Results: The tensile strength of the flexible band of the devices with inherent viscosity of 1.9 dL/g was 50.1 +/- 5.5 N (range 35.2-62.9 N, n = 11) and the devices with inherent viscosity of 1.3 dL/g had a tensile strength of 39.8 +/- 8.1 N (range 18.6-54.2 N, n = 11). Injection moulding of the polymer with lower inherent viscosity resulted in a longer flow distance. Both versions of the device had an effective tissue grip and complete haemostasis of renal arteries was verified. The device attached to the ovarian pedicle could be seen with ultrasound, and vessel compression and occlusion were verified by histology. Conclusions: Tests of functionality of the device showed complete haemostasis and good tissue grip. Devices with a band of sufficient length were easily applied and tightened in tissue.
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| 3. |
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| 4. |
- Norström, Sara H, et al.
(författare)
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Influences of dissolved organic carbon on stream water chemistry in two forested catchments in central Sweden
- 2010
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Ingår i: Biogeochemistry. - : Springer. - 0168-2563 .- 1573-515X. ; 101:1-3, s. 229-241
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Tidskriftsartikel (refereegranskat)abstract
- Stream water chemistry in two headwater streams draining two small, adjacent catchments in Bispgården, central Sweden was studied during the 2003 and 2004 growing seasons. The two catchments closely resemble each other in regard to size, shape and drainage density, with the major difference found in the area of wetland lining the streambeds. The emphasis of the study was to investigate the stream water chemistry of these closely resembling catchments, regarding the quality and quantity of dissolved organic carbon (DOC) and its influence on the concentrations of di- and trivalent cations. The streams showed significant differences in the content and size distribution of DOC and in the distribution of cations between the different size fractions. For both streams the high flow events induced by precipitation influenced the chemistry of the streams through increase of organic matter and its associated cations. Fanbergsbäcken, with relatively low pH and high DOC concentration, had a greater amount of high molecular mass (HMM) DOC to which approximately 75% of Al and Fe and about 50% of Ca and Mg were associated. Gråbergsbäcken, with a higher pH and lower DOC level, had approximately 65% of Al, 40% of Fe and 30% of Ca and Mg associated to its HMM DOC fraction. Sixteen different low molecular mass organic acids were found in the stream water, of which oxalic and lactic acid were present in the highest concentrations.
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| 5. |
- Docherty-Skogh, Ann-Charlott, et al.
(författare)
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Bone morphogenetic protein-2 delivered by hyaluronan-based hydrogel induces massive bone formation and healing of cranial defects in minipigs
- 2010
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Ingår i: Plastic and reconstructive surgery (1963). - 0032-1052 .- 1529-4242. ; 125:5, s. 1383-1392
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Tidskriftsartikel (refereegranskat)abstract
- Background: Reconstruction of large craniofacial bone defects is a challenge using bone transplants or alloplastic materials. The use of bone morphogenetic protein (BMP)-2 together with a suitable carrier is an attractive option that may facilitate new bone formation. The authors have developed a hydrogel that is formed in situ by the cross-linking of multifunctional hyaluronic acid and polyvinyl alcohol derivatives mixed with hydroxyapatite nanoparticles, in the presence of BMP-2. The aim of this study was to evaluate the suitability of the hydrogel as a carrier for BMP-2 in repairing critical size cranial defects in a minipig model. Methods: Cranial defects (2 × 4 cm) were created in 14 minipigs. The experimental groups were as follows: group 1, craniotomy and application of 5 ml of hydrogel with 1.25 mg of BMP-2 (n = 6); group 2, craniotomy and application of 5 ml of hydrogel without BMP-2 (n = 6); and group 3, craniotomy with no further treatment (n = 2). Results: After 3 months, computed tomographic and histologic examinations were performed. There was spontaneous ossification in the untreated group, but the healing was incomplete. The hydrogel alone demonstrated no further effects. The addition of 1.25 mg of BMP-2 to the hydrogel induced a greater than 100 percent increase in bone volume (p = 0.003) and complete healing of the defects. Histologic examination revealed compact lamellar bone in the BMP group without intertrabecular fibrous tissue, as was seen in the other groups. The hydrogel was resorbed completely within 3 months and, importantly, caused no inflammatory reaction. Conclusion: The injectable hydrogel may be favorable as a BMP-2 carrier for bone reconstruction.
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| 6. |
- Egeblad, Louise, et al.
(författare)
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Structural and functional studies of the human phosphoribosyltransferase domain containing protein 1
- 2010
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Ingår i: The FEBS Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 277:23, s. 4920-30
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Tidskriftsartikel (refereegranskat)abstract
- Human hypoxanthine-guanine phosphoribosyltransferase (HPRT) (EC 2.4.2.8) catalyzes the conversion of hypoxanthine and guanine to their respective nucleoside monophosphates. Human HPRT deficiency as a result of genetic mutations is linked to both Lesch-Nyhan disease and gout. In the present study, we have characterized phosphoribosyltransferase domain containing protein 1 (PRTFDC1), a human HPRT homolog of unknown function. The PRTFDC1 structure has been determined at 1.7 Å resolution with bound GMP. The overall structure and GMP binding mode are very similar to that observed for HPRT. Using a thermal-melt assay, a nucleotide metabolome library was screened against PRTFDC1 and revealed that hypoxanthine and guanine specifically interacted with the enzyme. It was subsequently confirmed that PRTFDC1 could convert these two bases into their corresponding nucleoside monophosphate. However, the catalytic efficiency (k(cat)/K(m)) of PRTFDC1 towards hypoxanthine and guanine was only 0.26% and 0.09%, respectively, of that of HPRT. This low activity could be explained by the fact that PRTFDC1 has a Gly in the position of the proposed catalytic Asp of HPRT. In PRTFDC1, a water molecule at the position of the aspartic acid side chain position in HPRT might be responsible for the low activity observed by acting as a weak base. The data obtained in the present study indicate that PRTFDC1 does not have a direct catalytic role in the nucleotide salvage pathway.
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| 7. |
- Olsén, Lena, et al.
(författare)
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Pharmacokinetics and effects of cetirizine in horses with insect bite hypersensitivity
- 2011
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Ingår i: The Veterinary Journal. - : Elsevier BV. - 1090-0233 .- 1532-2971. ; 187:3, s. 347-351
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Tidskriftsartikel (refereegranskat)abstract
- Horses with insect bite hypersensitivity (IBH) have difficulty in completely avoiding allergens, so effective treatment options are required. A randomised, placebo controlled and double blinded field study was conducted to determine the pharmacokinetics and efficacy in reducing dermatitis of the antihistamine cetirizine given orally at 0.4mg/kg twice daily for 3weeks. The influence of protection blankets and stabling were also investigated. The estimated maximum plasma concentration (C(max)) and trough plasma concentration of cetirizine were 135ng/mL and 18ng/mL, respectively. There was no difference in dermatitis reduction between the treatment and placebo groups (P=0.77). The findings indicated that cetirizine was of no apparent benefit in treating IBH at the dose rate tested. The use of blankets and stabling were shown to have favourable influence on the dermatitis (P<0.05) and may be the preferred options to prevent this condition.
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| 8. |
- Wicklein, Bernd, et al.
(författare)
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Functional hybrids based on biogenic nanofibrils and inorganic nanomaterials
- 2013
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 1:18, s. 5469-5478
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Tidskriftsartikel (refereegranskat)abstract
- This feature article reviews some of the recent work on the fabrication of functional hybrids based on biogenic nanofibers and inorganic nanomaterials with an emphasis on their functional properties and suggested potential applications. We also discuss some of the work oriented towards the formation of ordered materials in the pursuit of achieving a hierarchical construction. Besides the academic interest in biogenic nanomaterials, it is anticipated that the use of natural, abundant nanomaterials, e.g., cellulose, chitin, collagen, and silk, could provide affordable functional nanomaterials in developing countries.
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| 9. |
- Finlay, Roger, et al.
(författare)
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The role of fungi in biogenic weathering in boreal forest soils
- 2009
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Ingår i: Fungal Biology Reviews. - : Elsevier. - 1749-4613 .- 1878-0253. ; 23:4, s. 101-106
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Tidskriftsartikel (refereegranskat)abstract
- In this article we discuss the possible significance of biological processes, and of fungi in particular, in weathering of minerals. We consider biological activity to be a significant driver of mineral weathering in forest ecosystems. In these environments fungi play key roles in organic matter decomposition, uptake, transfer and cycling of organic and inorganic nutrients, biogenic mineral formation, as well as transformation and accumulation of metals. The ability of lichens, mutualistic symbioses between fungi and photobionts such as algae or cyanobacteria, to weather minerals is well documented. The role of mycorrhizal fungi forming symbioses with forest trees is less well understood, but the mineral horizons of boreal forests are intensively colonised by mycorrhizal mycelia which transfer protons and organic metabolites derived from plant photosynthates to mineral surfaces, resulting in mineral dissolution and mobilisation and redistribution of anionic nutrients and metal cations. The mycorrhizal mycelia, in turn provide efficient systems for the uptake and direct transport of mobilised essential nutrients to their host plants which are large sinks. Since almost all (99.99. %) non-suberised lateral plant roots involved in nutrient uptake are covered by ectomycorrhizal fungi, most of this exchange of metabolites must take place through the plant-fungus interface. This idea is still consistent with a linear relationship between soil mineral surface area and weathering rate since the mycelia that emanate from the tree roots will have a larger area of contact with minerals if the mineral surface area is higher. Although empirical models based on bulk soil solution chemistry may fit field data, we argue that biological processes make an important contribution to mineral weathering and that a more detailed mechanistic understanding of these must be developed in order to predict responses to environmental changes and anthropogenic impact. © 2010 The British Mycological Society.
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| 10. |
- Temnerud, Johan, 1969-, et al.
(författare)
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Landscape scale patterns in the character of natural organic matter in a Swedish boreal stream network
- 2009
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Ingår i: Hydrology and Earth System Sciences. - : Copernicus GmbH. - 1027-5606 .- 1607-7938. ; 13:9, s. 1567-1582
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Tidskriftsartikel (refereegranskat)abstract
- This paper defines landscape-scale patterns in the character of natural organic matter (NOM) and tests for relationships to catchment soil, vegetation and topography. The drainage network of a boreal catchment, subcatchment size 0.12-78 km(2), in Northern Sweden was sampled in August 2002 during a period of stable low water flow. The NOM was characterized with UV/Vis spectroscopy, fluorescence, XAD-8 fractionation (%humic substances), gel permeation chromatography (apparent molecular weight), and elemental composition (C:N). The largest spatial variation was found for C: N, absorbance ratio, and specific visible absorptivity. The lowest variation was in fluorescence index, %humic substances and molecular retention time. The variation in total organic carbon (TOC), iron and aluminium concentration was more than twice that of C: N. Between headwater and downstream sites no significant changes were distinguished in the NOM character. At stream reaches, junctions and lakes little change (<10%) in NOM character was observed. Common factor analysis and partial least squares regression (PLS) revealed that the spatial variation in surface coverage of lakes and mires could explain some of the variation of TOC and NOM character. Our suggestion is that the mosaic of landscape elements (different amounts of water from lakes, forest soil and mires) delivers NOM with varying characteristics to a channel network that mixes conservatively downstream, with possible small changes at some stream reaches, junctions and lakes.
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