| 1. |
- Andersson, Ida Marie, et al.
(författare)
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Effects of feed composition, protein denaturation and storage of milk serum protein/lactose powders on lactosylation
- 2021
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Ingår i: International Journal of Food Science and Technology. - : Wiley. - 0950-5423 .- 1365-2621. ; 56:1, s. 480-492
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Tidskriftsartikel (refereegranskat)abstract
- During whey powder production, the feed is subjected to several heat treatments which can cause lactosylation of proteins. In this study, lactosylation of whey proteins was evaluated in spray-dried powders before and after storage by varying the native protein fraction as well as the serum protein/lactose ratio in the powders. The lactosylation of native α-lactalbumin and β-lactoglobulin in the powders before storage was not affected to a large extent by the protein denaturation or if the feed had been heat treated in a high or low lactose environment. After storage (relative humidity of 23.5%, 30 °C, 25 days), the kinetic of lactosylation tended to increase with increasing native protein fraction and bulk protein content in the powders. An explanation could be that proteins dissolved in the lactose glassy structure might have a lower reactivity, while proteins present in the protein glassy structure with dissolved lactose may display higher lactosylation reactivity.
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| 2. |
- Wahlgren, Marie C, et al.
(författare)
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Adsorption of globular model proteins to silica and methylated silica surfaces and their elutability by dodecyltrimethylammonium bromide
- 1993
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Ingår i: Colloids and Surfaces A: Physicochemical and Engineering Aspects. - 0927-7757. ; 70:2, s. 139-149
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Tidskriftsartikel (refereegranskat)abstract
- The interaction between a cationic surfactant (dodecyltrimethylammonium bromide) and six model proteins adsorbed on to methylated silica and silica surfaces was investigated. The proteins were bovine serum albumin, cytochrome c, β-lactoglobulin, α-lactalbumin, lysozyme and ovalbumin. The adsorption of the proteins at pH 7 and their subsequent removal by surfactant were studied by in situ ellipsometry. The degree of desorption upon dilution and the degree of elutability were compared and no relationship between these parameters could be found, which indicates that the mechanisms behind the two ways of protein removal are quite different. Further, the degree of elutability by surfactant was related to the physicochemical properties of the proteins. It was found that the size, charge, temperature of denaturation and adiabatic compressibility influenced the degree of elutability at the hydrophilic negatively charged silica surfaces for those of the model proteins that were still adsorbed after buffer rinsing. Negatively charged proteins with high denaturation temperatures, indicating high structural stability, did not adsorb on to this surface (ovalbumin) or adsorbed to a very low degree and were desorbed upon rinsing with buffer (β-lactoglobulin). All proteins adsorbed on to the hydrophobic methylated silica and the parameters that seemed to influence the degree of elutability were size and shell hydrophobicity of the proteins.
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| 3. |
- Wahlgren, Marie C., et al.
(författare)
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The adsorption from solutions of β-lactoglobulin mixed with lactoferrin or lysozyme onto silica and methylated silica surfaces
- 1993
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Ingår i: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797. ; 158:1, s. 46-53
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Tidskriftsartikel (refereegranskat)abstract
- The adsorption from pure protein solutions and binary mixtures of proteins with opposite net charges was studied at pH 7 by in situ ellipsometry. The investigated proteins were β-lactoglobulin, lactoferrin, and lysozyme. On hydrophilic silica surfaces, β-lactoglobulin (negatively net charged) adsorbed in small amounts while lactoferrin and lysozyme (both positively net charged) adsorbed in higher quantities. All the proteins adsorbed readily to the methylated silica surfaces. On both surfaces the amounts of β-lactoglobulin adsorbed were higher and the ones for lactoferrin and lysozyme were lower in a high ionic strength buffer (I = 0.17 M) compared to a buffer with low ionic strength (I = 0.02 M). In mixtures of β-lactoglobulin and lactoferrin the proteins interact leading to high adsorbed amounts on the silica surface and to complete irreversibility with respect to rinsing with buffer. The effect is reduced by increasing the ionic strength of the buffer and by decreasing the overall concentration of proteins in the bulk. This is interpreted in terms of electrostatic interactions between the two proteins. The adsorbed amount from a β-lactoglobulin/lactoferrin mixture to a methylated silica surface is between the amounts for the pure proteins, and the adsorbate is a mixture of lactoferrin and β-lactoglobulin as indicated by measurements with radioactively labeled lactoferrin. An interesting observation was that the adsorbed amount from a β-lactoglobulin/lactoferrin mixture onto a methylated silica surface increased upon rinsing at high bulk concentrations and at low ionic strength. The adsorption from mixtures of β-lactoglobulin and lysozyme is also strongly influenced by electrostatic interactions. At low ionic strength a bulk precipitation takes place, which probably is the reason for the very high amounts adsorbed onto both surfaces examined. This effect is only partially reduced at higher ionic strength.
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| 4. |
- Öfverholm, Anna, et al.
(författare)
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Extended genetic analysis and tumor characteristics in over 4600 women with suspected hereditary breast and ovarian cancer
- 2023
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Ingår i: BMC Cancer. - : BioMed Central (BMC). - 1471-2407. ; 23:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundGenetic screening for pathogenic variants (PVs) in cancer predisposition genes can affect treatment strategies, risk prediction and preventive measures for patients and families. For decades, hereditary breast and ovarian cancer (HBOC) has been attributed to PVs in the genes BRCA1 and BRCA2, and more recently other rare alleles have been firmly established as associated with a high or moderate increased risk of developing breast and/or ovarian cancer. Here, we assess the genetic variation and tumor characteristics in a large cohort of women with suspected HBOC in a clinical oncogenetic setting.MethodsWomen with suspected HBOC referred from all oncogenetic clinics in Sweden over a six-year inclusion period were screened for PVs in 13 clinically relevant genes. The genetic outcome was compared with tumor characteristics and other clinical data collected from national cancer registries and hospital records.ResultsIn 4622 women with breast and/or ovarian cancer the overall diagnostic yield (the proportion of women carrying at least one PV) was 16.6%. BRCA1/2 PVs were found in 8.9% of women (BRCA1 5.95% and BRCA2 2.94%) and PVs in the other breast and ovarian cancer predisposition genes in 8.2%: ATM (1.58%), BARD1 (0.45%), BRIP1 (0.43%), CDH1 (0.11%), CHEK2 (3.46%), PALB2 (0.84%), PTEN (0.02%), RAD51C (0.54%), RAD51D (0.15%), STK11 (0) and TP53 (0.56%). Thus, inclusion of the 11 genes in addition to BRCA1/2 increased diagnostic yield by 7.7%. The yield was, as expected, significantly higher in certain subgroups such as younger patients, medullary breast cancer, higher Nottingham Histologic Grade, ER-negative breast cancer, triple-negative breast cancer and high grade serous ovarian cancer. Age and tumor subtype distributions differed substantially depending on genetic finding.ConclusionsThis study contributes to understanding the clinical and genetic landscape of breast and ovarian cancer susceptibility. Extending clinical genetic screening from BRCA1 and BRCA2 to 13 established cancer predisposition genes almost doubles the diagnostic yield, which has implications for genetic counseling and clinical guidelines. The very low yield in the syndrome genes CDH1, PTEN and STK11 questions the usefulness of including these genes on routine gene panels.
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| 5. |
- Allentoft, Morten E., et al.
(författare)
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100 ancient genomes show repeated population turnovers in Neolithic Denmark
- 2024
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Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 625, s. 329-337
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Tidskriftsartikel (refereegranskat)abstract
- Major migration events in Holocene Eurasia have been characterized genetically at broad regional scales1–4. However, insights into the population dynamics in the contact zones are hampered by a lack of ancient genomic data sampled at high spatiotemporal resolution5–7. Here, to address this, we analysed shotgun-sequenced genomes from 100 skeletons spanning 7,300 years of the Mesolithic period, Neolithic period and Early Bronze Age in Denmark and integrated these with proxies for diet (13C and 15N content), mobility (87Sr/86Sr ratio) and vegetation cover (pollen). We observe that Danish Mesolithic individuals of the Maglemose, Kongemose and Ertebølle cultures form a distinct genetic cluster related to other Western European hunter-gatherers. Despite shifts in material culture they displayed genetic homogeneity from around 10,500 to 5,900 calibrated years before present, when Neolithic farmers with Anatolian-derived ancestry arrived. Although the Neolithic transition was delayed by more than a millennium relative to Central Europe, it was very abrupt and resulted in a population turnover with limited genetic contribution from local hunter-gatherers. The succeeding Neolithic population, associated with the Funnel Beaker culture, persisted for only about 1,000 years before immigrants with eastern Steppe-derived ancestry arrived. This second and equally rapid population replacement gave rise to the Single Grave culture with an ancestry profile more similar to present-day Danes. In our multiproxy dataset, these major demographic events are manifested as parallel shifts in genotype, phenotype, diet and land use.
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| 6. |
- Allentoft, Morten E., et al.
(författare)
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Population genomics of post-glacial western Eurasia
- 2024
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Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 625:7994, s. 301-311
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Tidskriftsartikel (refereegranskat)abstract
- Western Eurasia witnessed several large-scale human migrations during the Holocene1–5. Here, to investigate the cross-continental effects of these migrations, we shotgun-sequenced 317 genomes—mainly from the Mesolithic and Neolithic periods—from across northern and western Eurasia. These were imputed alongside published data to obtain diploid genotypes from more than 1,600 ancient humans. Our analyses revealed a ‘great divide’ genomic boundary extending from the Black Sea to the Baltic. Mesolithic hunter-gatherers were highly genetically differentiated east and west of this zone, and the effect of the neolithization was equally disparate. Large-scale ancestry shifts occurred in the west as farming was introduced, including near-total replacement of hunter-gatherers in many areas, whereas no substantial ancestry shifts happened east of the zone during the same period. Similarly, relatedness decreased in the west from the Neolithic transition onwards, whereas, east of the Urals, relatedness remained high until around 4,000 bp, consistent with the persistence of localized groups of hunter-gatherers. The boundary dissolved when Yamnaya-related ancestry spread across western Eurasia around 5,000 bp, resulting in a second major turnover that reached most parts of Europe within a 1,000-year span. The genetic origin and fate of the Yamnaya have remained elusive, but we show that hunter-gatherers from the Middle Don region contributed ancestry to them. Yamnaya groups later admixed with individuals associated with the Globular Amphora culture before expanding into Europe. Similar turnovers occurred in western Siberia, where we report new genomic data from a ‘Neolithic steppe’ cline spanning the Siberian forest steppe to Lake Baikal. These prehistoric migrations had profound and lasting effects on the genetic diversity of Eurasian populations.
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| 7. |
- Angsten, Gertrud, et al.
(författare)
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Improved outcome in neonatal short bowel syndrome using parenteral fish oil in combination With ω-6/9 Lipid Emulsions
- 2012
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Ingår i: JPEN - Journal of Parenteral and Enteral Nutrition. - : Wiley. - 0148-6071 .- 1941-2444. ; 36:5, s. 587-595
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Tidskriftsartikel (refereegranskat)abstract
- Background:Newborn infants with short bowel syndrome (SBS) represent a high risk group of developing intestinal failure-associated liver disease (IFALD) which may be fatal. However, infants have a great capacity for intestinal growth and adaptation if IFALD can be prevented or reversed. A major contributing factor to IFALD may be the soybean oil-based intravenous lipid emulsions used since the introduction of parenteral nutrition (PN) 40 years ago. Methods:This retrospective study compares the outcome in 20 neonates with SBS treated with parenteral fish oil (Omegaven) in combination with omega-6/9 lipid emulsions (ClinOleic) with the outcome in a historical cohort of 18 patients with SBS who received a soybean oil-based intravenous lipid emulsion (Intralipid).Results:Median gestational age was 26 weeks in the treatment group and 35.5 weeks in the historical group. All patients were started on PN containing Intralipid that was switched to ClinOleic/Omegaven in the treatment group at a median age of 39 gestational weeks. In the treatment group, direct bilirubin levels were reversed in all 14 survivors with cholestasis (direct bilirubin >50 umol/). Median time to reversal was 2.9 months. Only 2 patients died of liver failure (10%). In the historical cohort, 6 patients (33%) died of liver failure and only 2 patients showed normalization of bilirubin levels.Conclusions:Parenteral fish oil in combination with omega-6/9 lipid emulsions was associated with improved outcome in premature neonates with SBS. When used instead of traditional soybean-based emulsions, this mixed lipid emulsion may facilitate intestinal adaptation by increasing the IFALD-free period.
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| 8. |
- Bergström, Peter, 1975-
(författare)
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Designing for the unknown : Didactical design for process-based assessment in technology-rich learning environments
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is based on a study of the development of education through theinnovative use of process-based assessment in technology-rich learningenvironments in teacher and nurse education. The study of process-basedassessment addresses the aim of creating a better understanding of the shiftin emphasis from teaching to learning with regard to theory and practice.The research questions address the use of process-based assessment, andhow the social relationships and issues of content can be understood intechnology-rich learning environments. A methodological approachinvolving design-based research was found to be especially applicable. Thestudy was designed in three iterative didactical design cycles for processbasedassessment in which the first and third cycles were analysed. Theempirical material comprises qualitative semi-structured interviews withteachers and students and questionnaires with students. The empiricalmaterial was analysed through inductive thematic analysis. The theoreticalanalyses in the comprising articles are mainly based on Bernstein’stheoretical framework for studying social relationships through concepts ofsymbolic power and control. For understanding change, with regard to theshift in emphasis from teaching to learning, the analysis is taken to a metalevelby applying Bernstein’s concept of pedagogical device.The results outline the shift in emphasis from teaching to learning fromboth a theoretical and practice perspective. Theoretically, the shift inemphasis from teaching to learning is based upon a shift in symbolic powerand control for teachers. In practice, the shift of symbolic power and controlbetween the teacher, student and content outline considerable overlapsbetween teacher-student, teacher-content and student-content. The overlapshighlight the empirical contribution in this thesis through the concept of“process” that is understood as a negotiation between teacher-student,teacher-content and student-content. The weakening symbolic powerrelationship made a multi-dimensional analysis of the teacher-studentcontentrelationship possible. Theoretically, the shift of symbolic poweroutlines a process of recontextualisation of a new discourse for teaching,learning and assessment. The multi-dimensional analysis highlights thetheoretical contributions to understanding the concept of discourse fromBernstein’s perspective through which the content and context create thediscourse. For practice, process-based assessment frames the notion ofdesigning for the unknown. Designing for the unknown is considered as aframework based upon a set of rules through which teachers and studentsadapt to a problematising approach in teaching, learning and assessment
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| 9. |
- Börjesson, Erik, et al.
(författare)
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Entrapment of air during imbibition of agglomerated powder beds
- 2017
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Ingår i: Journal of Food Engineering. - : Elsevier BV. - 0260-8774. ; 201, s. 26-35
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Tidskriftsartikel (refereegranskat)abstract
- Complete wetting is crucial for efficient recombination of powders. On the powder bed scale, wetting is governed solely by capillary forces and the resistance to flow, i.e. spontaneous imbibition. Slow or incomplete imbibition of the powder bed may lead to gelling of the liquid front, which will stop the recombination process and cause the formation of lumps, which is usually undesirable. In this study, the spontaneous imbibition of powder beds consisting of spray-dried dairy powders with diverse morphologies has been investigated. Uniform radial spreading of the imbibition front was seen in all the beds, but a large amount of air was trapped in the inter-particle free space in the imbibed volume. A positive correlation was found between bed porosity and the fraction of air trapped in the bed after imbibition. Since the amount of trapped air was calculated as a fraction of the porosity of the dry bed, this relation was unexpected. The large fraction of air trapped in the bed and the uniform radial spreading of the imbibition front indicate considerable heterogeneity of bed on the microscopic scale, but a homogenous structure on the macroscopic scale. Possible explanations of the large fraction of trapped air are the presence of local dead-end structures in the bed and film flow of the imbibing liquid.
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| 10. |
- Börjesson, Erik, et al.
(författare)
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Evaluation of particle measures relevant for powder bed porosity-A study of spray dried dairy powders
- 2014
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Ingår i: Powder Technology. - : Elsevier BV. - 0032-5910. ; 253, s. 453-463
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Tidskriftsartikel (refereegranskat)abstract
- The formation of lumps during large scale wetting of spray dried powders is a common problem in the industry. The result is a large energy demand if an efficient mixing is to be achieved at the industrial scale. If more knowledge regarding the phenomena governing lump formation is obtained, the unit operation could be optimized and made more efficient. As a part of increasing the understanding of lump formation, the wetting of the porous media that is a powder bed needs to be understood. This wetting relates to the structure and void space (porosity) of the powder bed, which is why a relation between powder bed porosity and readily obtainable powder particle morphology parameters is sought. In this study a thorough investigation of the morphology of five different spray dried milk powders, with arbitrary particle shapes, was performed using manual image analysis of scanning electron microscope (SEM) images as well as automated methods based on light scattering and projected image analysis. The results of the automated methods, when utilized on the complexly shaped samples, were validated by a comparison to the SEM image analysis. This enabled the development of a relation between powder morphology and powder bed porosity based on data from automated methods. The results indicate that automated methods based on light scattering underestimate the particle sizes of arbitrary shaped particles. Methods based on projected image analysis, however, show a better agreement with SEM image analysis. The developed relation between powder bed porosity and powder particle morphology is based on defining the bed as having either an "Agglomerates in fines", "Bicontinuous" or "Fines in agglomerates" structure. The structure of each powder is determined based on calculation of a "BedRatio" which is a function of the phi(agglomerate) and phi(fines) both shown to be readily obtainable by automated methods. The calculated porosities of the powders investigated in this study show a good agreement with experimental measurements and are considered to correspond well to earlier literature. It is, however, clear from the a experiments that care needs to be taken during bulk density measurement of spray dried powders so that no intra particle void space is taken into consideration in the calculations. (C) 2013 Elsevier B.V. All rights reserved.
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