| 1. |
- Allentoft, Morten E., et al.
(author)
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100 ancient genomes show repeated population turnovers in Neolithic Denmark
- 2024
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In: Nature. - 0028-0836 .- 1476-4687. ; 625, s. 329-337
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Journal article (peer-reviewed)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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| 2. |
- Allentoft, Morten E., et al.
(author)
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Population genomics of post-glacial western Eurasia
- 2024
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In: Nature. - 0028-0836 .- 1476-4687. ; 625:7994, s. 301-311
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Journal article (peer-reviewed)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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| 3. |
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| 4. |
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| 5. |
- Andersen, Sören M., et al.
(author)
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A scalable route to 5-substituted 3-isoxazolol fibrinolysis inhibitor AZD6564
- 2014
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In: Organic Process Research & Development. - : American Chemical Society (ACS). - 1083-6160 .- 1520-586X. ; 18:8, s. 952-959
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Journal article (peer-reviewed)abstract
- A practical and chromatography-free multikilogram synthesis of a 3-isoxazolol containing antifibrinolytic agent, AZD6564, has been developed in eight steps and 7% overall yield starting from methyl 2-chloroisonicotinate. Highlights in the synthesis are a Negishi coupling and an enzymatic resolution of a racemic ester.
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| 6. |
- Andersson, Lars Gustaf, et al.
(author)
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Rifbjerg!
- 2003
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In: Finns en plats på jorden. - 9163145928
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Book chapter (other academic/artistic)abstract
- Analysis of the poem "Rifbjerg!" by Danish writer Klaus Rifbjerg
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| 7. |
- Anrup, Roland, et al.
(author)
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Centrala universitetsvärden hotas av bolagiseringsidén
- 2013
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In: Dagens nyheter. - 1101-2447.
-
Journal article (pop. science, debate, etc.)abstract
- Högskolestiftelser. Förslaget att driva svenska universitet i stiftelseform öppnar för bolagisering. Men det är ingen riktig utredning, utan en politisk pamflett utan eftertanke. Privatisering av universitet hotar både oberoendet, forskningskvaliteten och samhällsnyttan, skriver 36 forskare vid svenska högskolor och universitet.
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| 8. |
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| 9. |
- Bak, Søren Alex, et al.
(author)
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Quantification of four ionophores in soil, sediment and manure using pressurised liquid extraction
- 2013
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In: Journal of Chromatography A. - 0021-9673 .- 1873-3778. ; 1307:September, s. 27-33
-
Journal article (peer-reviewed)abstract
- A multi-residue pressurised liquid extraction (PLE) methodology has been established for the determination of the four ionophores: lasalocid, monensin, salinomycin and narasin in solid environmental matrices. The PLE methodology is combined with solid phase extraction as clean-up using liquid chromatography coupled to tandem mass spectrometry applying electrospray ionisation for detection. The samples were freeze-dried prior to extraction. The absolute recoveries for soil and sediment ranged from 71 to 123% (relative standard deviation (RSDs) below 16%) and in the range 94–133% (RSDs 9–35%) for poultry manure. The final method allowed for the detection of four ionophores down to a few hundred ng kg−1 in natural solid matrices with limit of quantifications (LOQs) being 0.96, 0.87, 0.98, and 0.64 μg kg−1 in soil for lasalocid, monensin, salinomycin, and narasin, respectively. Corresponding LOQs in sediment were 1.28, 1.34, 1.39, and 0.78 μg kg−1 for the respective ionophores, while in manure the LOQs were 0.98, 1.01, 1.45, and 1.01 μg kg−1.
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| 10. |
- Bak, Søren Alex, et al.
(author)
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Quantification of four ionophores in soil, sediment and manure using pressurised liquid extraction
- 2013
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In: Journal of Chromatography A. - : Elsevier. - 0021-9673 .- 1873-3778. ; 1307:September, s. 27-33
-
Journal article (peer-reviewed)abstract
- A multi-residue pressurised liquid extraction (PLE) methodology has been established for the determination of the four ionophores: lasalocid, monensin, salinomycin and narasin in solid environmental matrices. The PLE methodology is combined with solid phase extraction as clean-up using liquid chromatography coupled to tandem mass spectrometry applying electrospray ionisation for detection. The samples were freeze-dried prior to extraction. The absolute recoveries for soil and sediment ranged from 71 to 123% (relative standard deviation (RSDs) below 16%) and in the range 94–133% (RSDs 9–35%) for poultry manure. The final method allowed for the detection of four ionophores down to a few hundred ng kg−1 in natural solid matrices with limit of quantifications (LOQs) being 0.96, 0.87, 0.98, and 0.64 μg kg−1 in soil for lasalocid, monensin, salinomycin, and narasin, respectively. Corresponding LOQs in sediment were 1.28, 1.34, 1.39, and 0.78 μg kg−1 for the respective ionophores, while in manure the LOQs were 0.98,1.01, 1.45, and 1.01 μg kg−1.
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| 11. |
- Bengtsson, Göran, et al.
(author)
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Microbial Diversity and PAH Catabolic Genes Tracking Spatial Heterogeneity of PAH Concentrations.
- 2012
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In: Microbial Ecology. - : Springer Science and Business Media LLC. - 1432-184X .- 0095-3628.
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Journal article (peer-reviewed)abstract
- We analyzed the within-site spatial heterogeneity of microbial community diversity, polyaromatic hydrocarbon (PAH) catabolic genotypes, and physiochemical soil properties at a creosote contaminated site. Genetic diversity and community structure were evaluated from an analysis of denaturant gradient gel electrophoresis (DGGE) of polymerase chain reaction (PCR)-amplified sequences of 16S rRNA gene. The potential PAH degradation capability was determined from PCR amplification of a suit of aromatic dioxygenase genes. Microbial diversity, evenness, and PAH genotypes were patchily distributed, and hot and cold spots of their distribution coincided with hot and cold spots of the PAH distribution. The analyses revealed a positive covariation between microbial diversity, biomass, evenness, and PAH concentration, implying that the creosote contamination at this site promotes diversity and abundance. Three patchily distributed PAH-degrading genotypes, NAH, phnA, and pdo1, were identified, and their abundances were positively correlated with the PAH concentration and the fraction of soil organic carbon. The covariation of the PAH concentration with the number and spatial distribution of catabolic genotypes suggests that a field site capacity to degrade PAHs may vary with the extent of contamination.
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| 12. |
- Bredewold, Obbo W, et al.
(author)
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Cardiovascular Risk Following Conversion to Belatacept From a Calcineurin Inhibitor in Kidney Transplant Recipients : A Randomized Clinical Trial
- 2023
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In: Kidney Medicine. - : Elsevier. - 2590-0595. ; 5:1
-
Journal article (peer-reviewed)abstract
- RATIONALE & OBJECTIVE: In kidney transplant recipients (KTRs), a belatacept-based immunosuppressive regimen is associated with beneficial effects on cardiovascular (CV) risk factors compared with calcineurin inhibitor (CNI)-based regimens. Our objective was to compare the calculated CV risk between belatacept and CNI (predominantly tacrolimus) treatments using a validated model developed for KTRs.STUDY DESIGN: Prospective, randomized, open-label, parallel-group, investigator-initiated, international multicenter trial.SETTING & PARTICIPANTS: KTRs aged 18-80 years with a stable graft function (estimated glomerular filtration rate > 20 mL/min/1.73 m2), 3-60 months after transplantation, treated with tacrolimus or cyclosporine A, were eligible for inclusion.INTERVENTION: Continuation with a CNI-based regimen or switch to belatacept for 12 months.OUTCOMES: Comparison of the change in the estimated 7-year risk of major adverse CV events and all-cause mortality, changes in traditional markers of CV health, as well as measures of arterial stiffness.RESULTS: Among the 105 KTRs randomized, we found no differences between the treatment groups in the predicted risk for major adverse CV events or mortality. Diastolic blood pressure, measured both centrally by using a SphygmoCor device and peripherally, was lower after the belatacept treatment than after the CNI treatment. The mean changes in traditional cardiovascular (CV) risk factors, including kidney transplant function, were otherwise similar in both the treatment groups. The belatacept group had 4 acute rejection episodes; 2 were severe rejections, of which 1 led to graft loss.LIMITATIONS: The heterogeneous baseline estimated glomerular filtration rate and time from transplantation to trial enrollment in the participants. A limited study duration of 1 year.CONCLUSIONS: We found no effects on the calculated CV risk by switching to the belatacept treatment. Participants in the belatacept group had not only lower central and peripheral diastolic blood pressure but also a higher rejection rate.FUNDING: The trial has received a financial grant from Bristol-Myers Squibb.TRIAL REGISTRATION: EudraCT no. 2013-001178-20.
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| 13. |
- Christensen, Emil Dalgaard, et al.
(author)
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The developing airway and gut microbiota in early life is influenced by age of older siblings
- 2022
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In: Microbiome. - : BioMed Central (BMC). - 2049-2618. ; 10:1
-
Journal article (peer-reviewed)abstract
- Background: Growing up with siblings has been linked to numerous health outcomes and is also an important determinant for the developing microbiota. Nonetheless, research into the role of having siblings on the developing microbiota has mainly been incidental.Results: Here, we investigate the specific effects of having siblings on the developing airway and gut microbiota using a total of 4497 hypopharyngeal and fecal samples taken from 686 children in the COPSAC2010 cohort, starting at 1 week of age and continuing until 6 years of age. Sibship was evaluated longitudinally and used for stratification. Microbiota composition was assessed using 16S rRNA gene amplicon sequencing of the variable V4 region. We found siblings in the home to be one of the most important determinants of the developing microbiota in both the airway and gut, with significant differences in alpha diversity, beta diversity, and relative abundances of the most abundant taxa, with the specific associations being particularly apparent during the first year of life. The age gap to the closest older sibling was more important than the number of older siblings. The signature of having siblings in the gut microbiota at 1 year was associated with protection against asthma at 6 years of age, while no associations were found for allergy.Conclusions: Having siblings is one of the most important factors influencing a child's developing microbiota, and the specific effects may explain previously established associations between siblings and asthma and infectious diseases. As such, siblings should be considered in all studies involving the developing microbiota, with emphasis on the age gap to the closest older sibling rather than the number of siblings. Video abstract.
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| 14. |
- Dalaei, Farima, et al.
(author)
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Body Contouring Surgery after Bariatric Surgery Improves Long-Term Health-Related Quality of Life and Satisfaction with Appearance : An International Longitudinal Cohort Study Using the BODY-Q
- 2024
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In: Annals of Surgery. - 0003-4932. ; 279:6, s. 1008-1017
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Journal article (peer-reviewed)abstract
- Objective: To examine health-related quality of life (HRQL) and satisfaction with appearance in patients who have undergone bariatric surgery (BS) with or without subsequent body contouring surgery (BCS) in relation to the general population normative for the BODY-Q. Background: The long-term impact of BS with or without BCS has not been established using rigorously developed and validated patient-reported outcome measures. The BODY-Q is a patient-reported outcome measure developed to measure changes in HRQL and satisfaction with appearance in patients with BS and BCS. Methods: Prospective BODY-Q data were collected from 6 European countries (Denmark, the Netherlands, Finland, Germany, Italy, and Poland) from June 2015 to February 2022 in a cohort of patients who underwent BS. Mixed-effects regression models were used to analyze changes in HRQL and appearance over time between patients who did and did not receive BCS and to examine the impact of patient-level covariates on outcomes. Results: This study included 24,604 assessments from 5620 patients. BS initially led to improved HRQL and appearance scores throughout the first postbariatric year, followed by a gradual decrease. Patients who underwent subsequent BCS after BS experienced a sustained improvement in HRQL and appearance or remained relatively stable for up to 10 years postoperatively. Conclusions: Patients who underwent BCS maintained an improvement in HRQL and satisfaction with appearance in contrast to patients who only underwent BS, who reported a decline in scores 1 to 2 years postoperatively. Our results emphasize the pivotal role that BCS plays in the completion of the weight loss trajectory.
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| 15. |
- Farnelid, Hanna, et al.
(author)
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Nitrogenase Gene Amplicons from Global Marine Surface Waters Are Dominated by Genes of Non-Cyanobacteria
- 2011
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In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:4, s. e19223-
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Journal article (peer-reviewed)abstract
- Cyanobacteria are thought to be the main N-2-fixing organisms (diazotrophs) in marine pelagic waters, but recent molecular analyses indicate that non-cyanobacterial diazotrophs are also present and active. Existing data are, however, restricted geographically and by limited sequencing depths. Our analysis of 79,090 nitrogenase (nifH) PCR amplicons encoding 7,468 unique proteins from surface samples (ten DNA samples and two RNA samples) collected at ten marine locations worldwide provides the first in-depth survey of a functional bacterial gene and yield insights into the composition and diversity of the nifH gene pool in marine waters. Great divergence in nifH composition was observed between sites. Cyanobacteria-like genes were most frequent among amplicons from the warmest waters, but overall the data set was dominated by nifH sequences most closely related to non-cyanobacteria. Clusters related to Alpha-, Beta-, Gamma-, and Delta-Proteobacteria were most common and showed distinct geographic distributions. Sequences related to anaerobic bacteria (nifH Cluster III) were generally rare, but preponderant in cold waters, especially in the Arctic. Although the two transcript samples were dominated by unicellular cyanobacteria, 42% of the identified non-cyanobacterial nifH clusters from the corresponding DNA samples were also detected in cDNA. The study indicates that non-cyanobacteria account for a substantial part of the nifH gene pool in marine surface waters and that these genes are at least occasionally expressed. The contribution of non-cyanobacterial diazotrophs to the global N-2 fixation budget cannot be inferred from sequence data alone, but the prevalence of non-cyanobacterial nifH genes and transcripts suggest that these bacteria are ecologically significant.
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| 16. |
- Gupta, Shashank, 1989-, et al.
(author)
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Amplicon sequencing provides more accurate microbiome information in healthy children compared to culturing
- 2019
-
In: Communications Biology. - : Springer Nature. - 2399-3642. ; 2:1
-
Journal article (peer-reviewed)abstract
- Next-Generation Sequencing (NGS) of 16S rRNA gene is now one of the most widely used application to investigate the microbiota at any given body site in research. Since NGS is more sensitive than traditional culture methods (TCMs), many studies have argued for them to replace TCMs. However, are we really ready for this transition? Here we compare the diagnostic efficiency of the two methods using a large number of samples (n = 1,748 fecal and n = 1,790 hypopharyngeal), among healthy children at different time points. Here we show that bacteria identified by NGS represented 75.70% of the unique bacterial species cultured in each sample, while TCM only identified 23.86% of the bacterial species found by amplicon sequencing. We discuss the pros and cons of both methods and provide perspective on how NGS can be implemented effectively in clinical settings.
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| 17. |
- Gupta, Shashank, 1989-, et al.
(author)
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Comparative analysis of the alveolar microbiome in COPD, ECOPD, Sarcoidosis, and ILD patients to identify respiratory illnesses specific microbial signatures
- 2021
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In: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 11:1
-
Journal article (peer-reviewed)abstract
- Studying respiratory illness-specific microbial signatures and their interaction with other micro-residents could provide a better understanding of lung microbial ecology. Each respiratory illness has a specific disease etiology, however, so far no study has revealed disease—specific microbial markers. The present study was designed to determine disease-specific microbial features and their interactions with other residents in chronic obstructive pulmonary diseases (stable and exacerbated), sarcoidosis, and interstitial lung diseases. Broncho-alveolar lavage samples (n = 43) were analyzed by SSU rRNA gene sequencing to study the alveolar microbiome in these diseases. A predominance of Proteobacteria followed by Firmicutes, Bacteroidetes, Actinobacteria, and Fusobacteria was observed in all the disease subsets. Shannon diversity was significantly higher in stable COPD when compared to exacerbated chronic obstructive pulmonary disease (ECOPD) (p = 0.0061), and ILD patient samples (p = 0.037). The lung microbiome of the patients with stable COPD was more diverse in comparison to ECOPD and ILD patients (p < 0.001). Lefse analysis identified 40 disease—differentiating microbial features (LDA score (log10) > 4). Species network analysis indicated a significant correlation (p < 0.05) of diseases specific microbial signature with other lung microbiome members. The current study strengthens the proposed hypothesis that each respiratory illness has unique microbial signatures. These microbial signatures could be used as diagnostic markers to differentiate among various respiratory illnesses.
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| 18. |
- Gupta, Shashank, 1989-, et al.
(author)
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Environmental shaping of the bacterial and fungal community in infant bed dust and correlations with the airway microbiota
- 2020
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In: Microbiome. - : BioMed Central (BMC). - 2049-2618. ; 8:1
-
Journal article (peer-reviewed)abstract
- Background: From early life, children are exposed to a multitude of environmental exposures, which may be of crucial importance for healthy development. Here, the environmental microbiota may be of particular interest as it represents the interface between environmental factors and the child. As infants in modern societies spend a considerable amount of time indoors, we hypothesize that the indoor bed dust microbiota might be an important factor for the child and for the early colonization of the airway microbiome. To explore this hypothesis, we analyzed the influence of environmental exposures on 577 dust samples from the beds of infants together with 542 airway samples from the Copenhagen Prospective Studies on Asthma in Childhood2010 cohort.Results: Both bacterial and fungal community was profiled from the bed dust. Bacterial and fungal diversity in the bed dust was positively correlated with each other. Bacterial bed dust microbiota was influenced by multiple environmental factors, such as type of home (house or apartment), living environment (rural or urban), sex of siblings, and presence of pets (cat and/or dog), whereas fungal bed dust microbiota was majorly influenced by the type of home (house or apartment) and sampling season. We further observed minor correlation between bed dust and airway microbiota compositions among infants. We also analyzed the transfer of microbiota from bed dust to the airway, but we did not find evidence of transfer of individual taxa.Conclusions: Current study explores the influence of environmental factors on bed dust microbiota (both bacterial and fungal) and its correlation with airway microbiota (bacterial) in early life using high-throughput sequencing. Our findings demonstrate that bed dust microbiota is influenced by multiple environmental exposures and could represent an interface between environment and child.
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| 19. |
- Haahr, Thor, et al.
(author)
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Vaginal dysbiosis in pregnancy associates with risk of emergency caesarean section: a prospective cohort study
- 2022
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In: Clinical Microbiology and Infection. - Oxford, United Kingdom : Elsevier. - 1198-743X .- 1469-0691. ; 28:4, s. 588-595
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Journal article (peer-reviewed)abstract
- Objectives: To investigate changes in vaginal microbiota during pregnancy, and the association between vaginal dysbiosis and reproductive outcomes.Methods: A total of 730 (week 24) and 666 (week 36) vaginal samples from 738 unselected pregnant women were studied by microscopy (Nugent score) and characterized by 16S rRNA gene sequencing. A novel continuous vaginal dysbiosis score was developed based on these methods using a supervised partial least squares model.Results: Among women with bacterial vaginosis in week 24 (n = 53), 47% (n = 25) also had bacterial vaginosis in week 36. In contrast, among women without bacterial vaginosis in week 24, only 3% (n = 18) developed bacterial vaginosis in week 36. Vaginal samples dominated by Lactobacillus crispatus (OR 0.35, 95% CI 0.20–0.60) and Lactobacillus iners (OR 0.40, 95% CI 0.23–0.68) in week 24 were significantly more stable by week 36 when compared with other vaginal community state types. Vaginal dysbiosis score at week 24 was associated with a significant increased risk of emergency, but not elective, caesarean section (OR 1.37, 955 CI 1.15–1.64, p < 0.001), suggesting a 37% increased risk per standard deviation increase in vaginal dysbiosis score.Conclusions: Changes in vaginal microbiota from week 24 to week 36 of pregnancy correlated with bacterial vaginosis status and vaginal community state type. A novel vaginal dysbiosis score was associated with a significantly increased risk of emergency, but not elective, caesarean section. This was not found for bacterial vaginosis or any vaginal community state type and could point to the importance of investigating vaginal dysbiosis as a nuanced continuum instead of crude clusters.
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| 20. |
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| 21. |
- Hedegaard Sørensen, Claus, et al.
(author)
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Mål i national transportplanlægning. : Kan vi lære af Norge og Sverige?
- 2009
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In: Trafik & Veje. - 1903-7384. ; 86:8, s. 26-28
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Journal article (pop. science, debate, etc.)abstract
- Anvendelsen af mål og indikatorer i infrastrukturplanlægningen er som sådan ikke nyt. I både Norge og Sverige er der lang tradition for at anvende overordnede mål med tilhørende indikatorer i den nationale transportplanlægning. I denne artikel præsenteres de to landes erfaringer med henblik på at se, om Danmark kan lære noget af de to skandinaviske broderlande hvad angår anvendelse af mål i infrastrukturplanlægningen.
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| 22. |
- Heins, Anna Lena, et al.
(author)
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Quantitative flow cytometry to understand population heterogeneity in response to changes in substrate availability in escherichia coli and saccharomyces cerevisiae chemostats
- 2019
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In: Frontiers in Bioengineering and Biotechnology. - : Frontiers Media SA. - 2296-4185. ; 7:AUG
-
Journal article (peer-reviewed)abstract
- Microbial cells in bioprocesses are usually described with averaged parameters. But in fact, single cells within populations vary greatly in characteristics such as stress resistance, especially in response to carbon source gradients. Our aim was to introduce tools to quantify population heterogeneity in bioprocesses using a combination of reporter strains, flow cytometry, and easily comprehensible parameters. We calculated mean, mode, peak width, and coefficient of variance to describe distribution characteristics and temporal shifts in fluorescence intensity. The skewness and the slope of cumulative distribution function plots illustrated differences in distribution shape. These parameters are person-independent and precise. We demonstrated this by quantifying growth-related population heterogeneity of Saccharomyces cerevisiae and Escherichia coli reporter strains in steady-state of aerobic glucose-limited chemostat cultures at different dilution rates and in response to glucose pulses. Generally, slow-growing cells showed stronger responses to glucose excess than fast-growing cells. Cell robustness, measured as membrane integrity after exposure to freeze-thaw treatment, of fast-growing cells was strongly affected in subpopulations of low membrane robustness. Glucose pulses protected subpopulations of fast-growing but not slower-growing yeast cells against membrane damage. Our parameters could successfully describe population heterogeneity, thereby revealing physiological characteristics that might have been overlooked during traditional averaged analysis.
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| 23. |
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| 24. |
- Jensen, Pernille Linnert, et al.
(author)
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Proteomic Analysis of Human Blastocoel Fluid and Blastocyst Cells
- 2013
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In: Stem Cells and Development. - : Mary Ann Liebert Inc. - 1547-3287 .- 1557-8534. ; 22:7, s. 1126-1135
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Journal article (peer-reviewed)abstract
- Human embryonic stem cells (hESCs) are derived from the inner cell mass (ICM) of the blastocyst and can differentiate into any cell type in the human body. These cells hold a great potential for regenerative medicine, but in order to obtain enough cells needed for medical treatment, culture is required on a large scale. In the undifferentiated state, hESCs appear to possess an unlimited potential for proliferation but optimal, defined and safe culture conditions remains a challenge. The aim of the present study was to identify proteins in the natural environment of undifferentiated hESCs, namely the blastocoel fluid, which is in contact with all the cells in the blastocyst, including hESCs. Fifty-three surplus human blastocysts were donated after informed consent and blastocoel fluid was isolated by micromanipulation. Using highly sensitive nano high pressure liquid chromatography tandem mass spectrometry, 286 proteins were identified in the blastocoel fluid and 1307 proteins in the corresponding cells of the blastocyst. Forty-two were previously uncharacterized proteins - eight of these originated from the blastocoel fluid. Furthermore, several heat shock proteins (Hsp27, Hsp60, Hsc70 and Hsp90) were identified in blastocoel fluid together with zona pellucida proteins (ZP2-4), Vitamin D binding protein and Retinol binding protein. Proteins that regulate ciliary assembly and function were also identified, including Bardet-biedl syndrome protein 7. This study has identified numerous proteins which cells from the ICM of the human blastocyst are exposed to via the blastocoel fluid. These results can be an inspiration for the development of improved culture conditions for hESCs.
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| 25. |
- Juhl Andersen, Søren, et al.
(author)
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Global trends in the performance of large wind farms based on high-fidelity simulations
- 2020
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In: Wind Energy Science. - : Copernicus GmbH. - 2366-7443 .- 2366-7451. ; 5:4, s. 1689-1703
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Journal article (peer-reviewed)abstract
- A total of 18 high-fidelity simulations of large wind farms have been performed by three different institutions using various inflow conditions and simulation setups. The setups differ in how the atmospheric turbulence, wind shear and wind turbine rotors are modeled, encompassing a wide range of commonly used modeling methods within the large eddy simulation (LES) framework. Various turbine spacings, atmospheric turbulence intensity levels and incoming wind velocities are considered. The work performed is part of the International Energy Agency (IEA) wind task Wakebench and is a continuation of previously published results on the subject. This work aims at providing a methodology for studying the general flow behavior in large wind farms in a systematic way. It seeks to investigate and further understand the global trends in wind farm performance, with a focus on variability.Parametric studies first map the effect of various parameters on large aligned wind farms, including wind turbine spacing, wind shear and atmospheric turbulence intensity. The results are then aggregated and compared to engineering models as well as LES results from other investigations to provide an overall picture of how much power can be extracted from large wind farms operating below the rated level. The simple engineering models, although they cannot capture the variability features, capture the general trends well. Response surfaces are constructed based on the large number of aggregated LES data corresponding to a wide range of large wind farm layouts. The response surfaces form a basis for mapping the inherently varying power characteristics inside very large wind farms, including how much the turbines are able to exploit the turbulent fluctuations within the wind farms and estimating the associated uncertainty, which is valuable information useful for risk mitigation.
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| 26. |
- Jungstedt, Erik
(author)
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Deformation and Fracture Behavior of Transparent Wood-Polymer Biocomposites
- 2022
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Doctoral thesis (other academic/artistic)abstract
- Transparent wood-polymer biocomposites (TWPBs) are interesting wood-based materials with a unique combination of optical transmittance and mechanical properties. The wood substrate is delignified (removal of lignin) while the wood microstructure is preserved. In this thesis, the deformation and fracture behavior of TWPBs are investigated, and material properties are determined. In addition, a method is presented for identifying orthotropic and fracture properties from single small and thin specimen geometries of wood composites by minimizing the discrepancy between experimentally measured and numerically generated strain fields. Material model parameters in the finite element method (FEM) are updated by optimization routines (FEMU). The focus of the thesis is on TWPBs, but wood fiber biocomposites are included to develop the FEMU approach. InPaper I and II, the mechanical and optical behavior of laminated and single lamina of TWPBs are investigated. Orthotropic mechanical properties, such as elastic stiffness parameters and tensile strength, are determined along and across the fiber direction, and the deformation mechanisms are characterized. Reducedanisotropic ratio (e.g., a ratio of in-plane elastic stiffness parameters), increased wood cell wall effective properties, and improved stress transfer by a more homogeneous strain field are found for TWPBs compared to native wood. Lamination moderates the weakest properties and allows structural tailoring, making it more suitable as a load-bearing material.In Paper III and IV, fracture and deformation mechanisms are investigated, and the fracture properties are determined using cohesive zone models (CZM) along and across the fiber direction. This approach made it possible to explain 90° crack deflection phenomenon. Large fracture process zones (FPZ) dominated by the cell wall properties are observed, involving fiber pull-out with large cohesive strength in the fiber direction. Also, cross-over bridging mechanisms by cell wall peeling in the transverse fiber direction, with low cohesive strength properties. Longitudinal fracture properties of native wood are improved with a polymer matrix, while the transverse fracture properties are reduced as well as the size of the FPZ.In Paper V, random and oriented wood-fiber biocomposites are investigated, relating nano- and microscale structures to macroscopic mechanical properties. Orthotropic elastic-plastic material parameters are identified from off-axis tensile tests by using FEMU. Fracture mechanisms are related to microstructural features by the use of supporting in situ tensile tests in a scanning electron microscope.
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| 27. |
- Karlsson, Staffan, et al.
(author)
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An Enantioselective Hydrogenation of an Alkenoic Acid as a Key Step in the Synthesis of AZD2716
- 2016
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In: Organic Process Research & Development. - : American Chemical Society (ACS). - 1083-6160 .- 1520-586X. ; 20:2, s. 262-269
-
Journal article (peer-reviewed)abstract
- A classical resolution of a racemic carboxylic acid through salt formation and an asymmetric hydrogenation of an α,β-unsaturated carboxylic acid were investigated in parallel to prepare an enantiomerically pure alkanoic acid used as a key intermediate in the synthesis of an antiplaque candidate drug. After an extensive screening of rhodium- and ruthenium-based catalysts, we developed a rhodium-catalyzed hydrogenation that gave the alkanoic acid with 90% ee, and after a subsequent crystallization with (R)-1-phenylethanamine, the ee was enriched to 97%. The chiral acid was then used in sequential Negishi and Suzuki couplings followed by basic hydrolysis of a nitrile to an amide to give the active pharmaceutical ingredient in 22% overall yield.
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| 28. |
- Laustsen, Søren Ravn, et al.
(author)
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Præoperativ funktionel magnetisk resonans-billeddannelse hos patienter med hjernetumor
- 2010
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In: Ugeskrift for læger. - 0041-5782 .- 1603-6824. ; 172:35, s. 2370-2376
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Journal article (peer-reviewed)abstract
- INTRODUCTION: Functional Magnetic Resonance Imaging (fMRI) allows important functions in the brain cortex to be mapped noninvasively. The purpose with this work was to investigate a possible correlation between the distance from the tumour margin to fMRI activity and postoperative neurological deficits by means of a standardised method for measurement of distance. A second purpose was to investigate the influence of preoperative fMRI on the neurosurgical decision-making process. MATERIAL AND METHODS: Retrospective study of 25 patients. The inclusion criteria were surgery or biopsy after fMRI plus a three-month postoperative assessment. A total of 14 patients complied with these requirements (six men and eight women, the mean age was 39 years). fMRI raw data was collected using a three tesla magnetic resonance scanner (Signa HDx R14M5, GE Healthcare). The distance from the tumour margin to fMRI activation was measured using GE-reformat version 4.2 after raw data had been postprocessed using GE BrainwavePA version 1.3.08130. The neurosurgeons valuation of fMRI in the preoperative decision-making process was obtained using a standard questionnaire. RESULTS: There was a trend of association between distance from tumour to eloquent functional areas and the patients' postoperative neurological outcome (Fisher's exact test: distance < 15 mm, p = 0.43; distance < 10 mm, p = 0.14). fMRI proved very useful when deciding whether to operate or not (42%), when deciding the surgical approach (50%) and when deciding the extent of the surgical approach (83%). CONCLUSION: The standardised method for measurement of distance between tumour margin and fMRI activity can contribute to the preoperative risk assessment in patients with brain tumours.
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| 29. |
- Ledri, Marco, et al.
(author)
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Differential Effect of Neuropeptides on Excitatory Synaptic Transmission in Human Epileptic Hippocampus.
- 2015
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In: The Journal of Neuroscience. - 1529-2401. ; 35:26, s. 9622-9631
-
Journal article (peer-reviewed)abstract
- Development of novel disease-modifying treatment strategies for neurological disorders, which at present have no cure, represents a major challenge for today's neurology. Translation of findings from animal models to humans represents an unresolved gap in most of the preclinical studies. Gene therapy is an evolving innovative approach that may prove useful for clinical applications. In animal models of temporal lobe epilepsy (TLE), gene therapy treatments based on viral vectors encoding NPY or galanin have been shown to effectively suppress seizures. However, how this translates to human TLE remains unknown. A unique possibility to validate these animal studies is provided by a surgical therapeutic approach, whereby resected epileptic tissue from temporal lobes of pharmacoresistant patients are available for neurophysiological studies in vitro. To test whether NPY and galanin have antiepileptic actions in human epileptic tissue as well, we applied these neuropeptides directly to human hippocampal slices in vitro. NPY strongly decreased stimulation-induced EPSPs in dentate gyrus and CA1 (up to 30 and 55%, respectively) via Y2 receptors, while galanin had no significant effect. Receptor autoradiographic binding revealed the presence of both NPY and galanin receptors, while functional receptor binding was only detected for NPY, suggesting that galanin receptor signaling may be impaired. These results underline the importance of validating findings from animal studies in human brain tissue, and advocate for NPY as a more appropriate candidate than galanin for future gene therapy trials in pharmacoresistant TLE patients.
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| 30. |
- Quinson, Jonathan, et al.
(author)
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Surfactant-Free Colloidal Syntheses of Gold-Based Nanomaterials in Alkaline Water and Mono-alcohol Mixtures
- 2023
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In: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 35:5, s. 2173-2190
-
Journal article (peer-reviewed)abstract
- Gold nanoparticles (Au NPs) and gold-based nanomaterials combine unique properties relevant for medicine, imaging, optics, sensing, catalysis, and energy conversion. While the Turkevich-Frens and Brust-Schiffrin methods remain the state-of-the-art colloidal syntheses of Au NPs, there is a need for more sustainable and tractable synthetic strategies leading to new model systems. In particular, stabilizers are almost systematically used in colloidal syntheses, but they can be detrimental for fundamental and applied studies. Here, a surfactant-free synthesis of size-controlled colloidal Au NPs stable for months is achieved by the simple reduction of HAuCl4 at room temperature in alkaline solutions of low-viscosity mono-alcohols such as ethanol or methanol and water, without the need for any other additives. Palladium (Pd) and bimetallic AuxPdy NPs, nanocomposites and multimetallic samples, are also obtained and are readily active (electro)catalysts. The multiple benefits over the state-of-the-art syntheses that this simple synthesis bears for fundamental and applied research are highlighted.
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| 31. |
- Rasmussen, Mads, et al.
(author)
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Blood Pressure Thresholds and Neurologic Outcomes After Endovascular Therapy for Acute Ischemic Stroke: An Analysis of Individual Patient Data From 3 Randomized Clinical Trials.
- 2020
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In: JAMA neurology. - : American Medical Association (AMA). - 2168-6157 .- 2168-6149. ; 77:5, s. 622-31
-
Journal article (peer-reviewed)abstract
- The optimal blood pressure targets during endovascular therapy (EVT) for acute ischemic stroke (AIS) are unknown.To study whether procedural blood pressure parameters, including specific blood pressure thresholds, are associated with neurologic outcomes after EVT.This retrospective cohort study included adults with anterior-circulation AIS who were enrolled in randomized clinical trials assessing anesthetic strategy for EVT between February 2014 and February 2017. The trials had comparable blood pressure protocols, and patients were followed up for 90 days. A total of 3630 patients were initially approached, and 3265 patients were excluded.Endovascular therapy.The primary efficacy variable was functional outcome as defined by the modified Rankin Scale (mRS) score at 90 days. Associations of blood pressure parameters and time less than and greater than mean arterial blood pressure (MABP) thresholds with outcome were analyzed.Of the 365 patients included in the analysis, the mean (SD) age was 71.4 (13.0) years, 163 were women (44.6%), and the median National Institutes of Health Stroke Scale score was 17 (interquartile range [IQR], 14-21). For the entire cohort, 182 (49.9%) received general anesthesia and 183 (50.1%) received procedural sedation. A cumulated period of minimum 10 minutes with less than 70 mm Hg MABP (adjusted OR, 1.51; 95% CI, 1.02-2.22) and a continuous episode of minimum 20 minutes with less than 70 mm Hg MABP (adjusted OR, 2.30; 95% CI, 1.11-4.75) were associated with a shift toward higher 90-day mRS scores, corresponding to a number needed to harm of 10 and 4, respectively. A cumulated period of minimum 45 minutes with greater than 90 mm Hg MABP (adjusted OR, 1.49; 95% CI, 1.11-2.02) and a continuous episode of minimum 115 minutes with greater than 90 mm Hg MABP (adjusted OR, 1.89; 95% CI, 1.01-3.54) were associated with a shift toward higher 90-day mRS scores, corresponding to a number needed to harm of 10 and 6, respectively.Critical MABP thresholds and durations for poor outcome were found to be MABP less than 70 mm Hg for more than 10 minutes and MABP greater than 90 mm Hg for more than 45 minutes, both durations with a number needed to harm of 10 patients. Mean arterial blood pressure may be a modifiable therapeutic target to prevent or reduce poor functional outcome after EVT.
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| 32. |
- Rysgaard, Søren, et al.
(author)
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A mobile observatory powered by sun and wind for near real time measurements of atmospheric, glacial, terrestrial, limnic and coastal oceanic conditions in remote off-grid areas
- 2022
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In: HardwareX. - : Elsevier BV. - 2468-0672. ; 12
-
Journal article (peer-reviewed)abstract
- Climate change is rapidly altering the Arctic environment. Although long-term environmental observations have been made at a few locations in the Arctic, the incomplete coverage from ground stations is a main limitation to observations in these remote areas. Here we present a wind and sun powered multi-purpose mobile observatory (ARC-MO) that enables near real time measurements of air, ice, land, rivers, and marine parameters in remote off-grid areas. Two test units were constructed and placed in Northeast Greenland where they have collected data from cabled and wireless instruments deployed in the environment since late summer 2021. The two units can communicate locally via WiFi (units placed 25 km apart) and transmit near-real time data globally over satellite. Data are streamed live and accessible from (https://gios.org). The cost of one mobile observatory unit is c. 304.000€. These test units demonstrate the possibility for integrative and automated environmental data collection in remote coastal areas and could serve as models for a proposed global observatory system.
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| 33. |
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| 34. |
- Skov, Karin, et al.
(author)
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Det nordiske nyreudvekslingsprogram
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In: Ugeskrift for Læger. - 1603-6824 .- 0041-5782. ; , s. 1-6
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Journal article (peer-reviewed)abstract
- This review describes the ScandiaTransplant Kidney Exchange Programme and the background of renal exchange programmes gaining popularity worldwide, possibilities and limitations of the programmes, the ethical aspects and perspectives. The first kidney exchanges between Danish and Swedish countries were performed in 2019, and until now 23 exchanges and transplantations have been performed. All surgical procedures have been performed simultaneously and/or coordinated at different hospitals in Scandinavia, and the kidney grafts were transported between the participating units
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| 35. |
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| 36. |
- Stenström, Johan, et al.
(author)
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Carl Snoilsky och Bellman
- 2010
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In: Bellman i billed og digt. Rapport fra Bellmanfestivalen i København september-oktober 2006. - 9788779172692 ; , s. 223-241
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Book chapter (other academic/artistic)
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| 37. |
- Stenström, Johan, et al.
(author)
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Några nedslag i 1800-talets Fredmanikonografi
- 2010
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In: Bellman i billed og digt. Rapport fra Bellmanfestivalen i København september-oktober 2006. - 9788779172692 ; , s. 50-74
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Book chapter (other academic/artistic)
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| 38. |
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| 39. |
- Wan, Feng, et al.
(author)
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Ultrasmall TPGS-PLGA Hybrid Nanoparticles for Site-Specific Delivery of Antibiotics into Pseudomonas aeruginosa Biofilms in Lungs
- 2020
-
In: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 12:1, s. 380-389
-
Journal article (peer-reviewed)abstract
- Inhaled antibiotic treatment of cystic fibrosis-related bacterial biofilm infections is challenging because of the pathological environment of the lungs. Here, we present an "environment-adaptive" nanoparticle composed of a solid poly lactic-co-glycolic acid (PLGA) core and a mucus-inert, enzymatically cleavable shell of d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) for the site-specific delivery of antibiotics to bacterial biofilms via aerosol administration. The hybrid nanoparticles with ultrasmall size were self-assembled via a nanoprecipitation process by using a facile microfluidic method. The interactions of the nanoparticles with the biological barriers were comprehensively investigated by using cutting-edge techniques (e.g., quartz crystal microbalance with dissipation monitoring, total internal reflection fluorescence microscopy-based particle tracking, in vitro biofilm model cultured in a flow-chamber system, and quantitative imaging analysis). Our results suggest that the mucus-inert, enzymatically cleavable TPGS shell enables the nanoparticles to penetrate through the mucus, accumulate in the deeper layer of the biofilms, and serve as sustained release depot, thereby improving the killing efficacy of azithromycin (a macrolide antibiotic) against biofilm-forming Pseudomonas aeruginosa. In conclusion, the ultrasmall TPGS-PLGA hybrid nanoparticles represent an efficient delivery system to overcome the multiple barriers and release antibiotics in a sustained manner in the vicinity of the biofilm-forming bacteria.
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| 40. |
- Weinreich, Ilse, et al.
(author)
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Scandiatransplant acceptable mismatch program : 10 years with an effective strategy for transplanting highly sensitized patients
- 2022
-
In: American Journal of Transplantation. - : John Wiley & Sons. - 1600-6135 .- 1600-6143. ; 22:12, s. 2869-2879
-
Journal article (peer-reviewed)abstract
- In March 2009, the Scandiatransplant acceptable mismatch program (STAMP) was introduced as a strategy toward improving kidney allocation to highly sensitized patients. Patients with a transplantability score ≤ 2% are potential candidates for the program. Samples are analyzed and acceptable antigens (HLA-A, B, C, DRB1, DRB3/4/5, DQB1, DQA1, DPB1, DPA1) are defined by the local tissue typing laboratory and finally evaluated by a steering committee. In the matching algorithm, patients have the highest priority when the donor's antigens are all among the recipient's own or acceptable HLA antigens. In the period from 2009 to 2020, we have transplanted 278 highly sensitized kidney patients through the program. The graft survival of the STAMP patients was compared with 9002 deceased donor kidney-transplanted patients, transplanted in the same time period. The 10-year graft survival was 73.4% (95% CI: 60.3-90.0) for STAMP and 82.9% (95% CI: 81.6-84.3) for the reference group. (p = .2). In conclusion, the 10-year allograft survival demonstrates that the STAMP allocation algorithm is immunological safe. The program is continuously monitored and evaluated, and the introduction of matching for all HLA loci is a huge improvement to the program and demonstrate technical adaptability as well as clinical flexibility in a de-centralized organization.
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| 41. |
- Wenjing, Zhang, et al.
(author)
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Electrospun nanofiber materials for energy and environmental applications
- 2019
-
In: Energy Procedia. - : Elsevier. - 1876-6102.
-
Conference paper (peer-reviewed)abstract
- Electrospinning is the one of the most versatile techniques to design nanofiber materials with numerous applications in the fields of energy conversion, catalytic chemistry, liquid and gas filtration.1 By electrospinning, complex structures can be designed from a rich variety of materials including polymers, metals, ceramics and composite, with the ability to control composition, morphology and secondary structure and tailor performance and functionality for specific applications. Moreover, with recent developments in the design of electrospinning equipment and availability of industrial-scale electrospinning technologies with production rates of several thousands of square meters per day new opportunities for electrospinning are imminent. With this, the advanced research on materials performed in our labs is getting closer to the commercialization of new products for applications in fields of energy and environment.An overview will be given on electrospinning activities at DTU Energy that address the sizable challenges in energy and environmental applications by electrospinning: 1. Electrospun perovskite oxide nanofiber electrode for use in solid oxide fuel cells. In this application, a (La0.6Sr0.4)0.99CoO3-δ cathode was shaped into 3-dimensional thin-film by so-gel assisted electrospinning method combined with calcination and sintering; 2. Electrospun nanofiber materials for gas adsorption. Both the advantages and challenges of using electrospun nanofiber materials will be discussed, in terms of electrochemical performance, surface area, packing efficiency and mechanical stability.
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| 42. |
- Woldbye, David P D, et al.
(author)
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Adeno-associated viral vector-induced overexpression of neuropeptide Y Y2 receptors in the hippocampus suppresses seizures.
- 2010
-
In: Brain. - : Oxford University Press (OUP). - 1460-2156 .- 0006-8950. ; 133:Pt 9, s. 2778-2788
-
Journal article (peer-reviewed)abstract
- Gene therapy using recombinant adeno-associated viral vectors overexpressing neuropeptide Y in the hippocampus exerts seizure-suppressant effects in rodent epilepsy models and is currently considered for clinical application in patients with intractable mesial temporal lobe epilepsy. Seizure suppression by neuropeptide Y in the hippocampus is predominantly mediated by Y2 receptors, which, together with neuropeptide Y, are upregulated after seizures as a compensatory mechanism. To explore whether such upregulation could prevent seizures, we overexpressed Y2 receptors in the hippocampus using recombinant adeno-associated viral vectors. In two temporal lobe epilepsy models, electrical kindling and kainate-induced seizures, vector-based transduction of Y2 receptor complementary DNA in the hippocampus of adult rats exerted seizure-suppressant effects. Simultaneous overexpression of Y2 and neuropeptide Y had a more pronounced seizure-suppressant effect. These results demonstrate that overexpression of Y2 receptors (alone or in combination with neuropeptide Y) could be an alternative strategy for epilepsy treatment.
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| 43. |
- Zhang, Wenjing, et al.
(author)
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Highly Structured Nanofiber Zeolite Materials for Biogas Upgrading
- 2020
-
In: Energy Technology. - : John Wiley & Sons. - 2194-4296 .- 2194-4288. ; 8:1
-
Journal article (peer-reviewed)abstract
- Hierarchical zeolite composite nanofibers are designed using an electrospinning technique with post‐carbonization processing to form mechanically strong pellets for biogas upgrading. A ZSM‐5 nanopowder (zeolite) and a polyvinylpyrrolidone (PVP) polymer are electrospun to form ZSM/PVP composite nanofibers, which are transformed into a ZSM and carbon composite nanofiber (ZSM/C) by a two‐step heat treatment. The ZSM/C nanofibers show a 30.4% increase in Brunauer–Emmett–Teller (BET) surface area compared with the non‐structured ZSM‐5 nanopowder. Using ideal adsorbed solution theory, CO2‐over‐CH4 selectivity of 20 and CO2 uptake of 2.15 mmolg−1 at 293 K at 1 bar for ZSM/C nanofibers are obtained. For the efficient use of adsorbents in pressure swing adsorption operation, the nanofibers are structured into ZSM/C pellets that offer a maximum tensile strength of 6.46 MPa to withstand pressure swings. In the breakthrough tests, the CO2 uptake of the pellets reach 3.18 mmolg−1 at 293 K at 4 bar after 5 breakthrough adsorption–desorption cycles, with a much higher mass transfer coefficient of 1.24 ms−1 and CO2 uptake rate of 2.4 mg of CO2 g−1s−1, as compared with other structured zeolite adsorbents.
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| 44. |
- Ögren, Magnus, 1977-, et al.
(author)
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Numerical simulations of NMR relaxation in chalk using local Robin boundary conditions
- 2019
-
In: Journal of magnetic resonance. - : Elsevier. - 1090-7807 .- 1096-0856. ; 308
-
Journal article (peer-reviewed)abstract
- The interpretation of nuclear magnetic resonance (NMR) data is of interest in a number of fields. In Ögren [Eur. Phys. J. B (2014) 87: 255] local boundary conditions for random walk simulations of NMR relaxation in digital domains were presented. Here, we have applied those boundary conditions to large, three-dimensional (3D) porous media samples. We compared the random walk results with known solutions and then applied them to highly structured 3D domains, from images derived using synchrotron radiation CT scanning of North Sea chalk samples. As expected, there were systematic errors caused by digitalization of the pore surfaces so we quantified those errors, and by using linear local boundary conditions, we were able to significantly improve the output. We also present a technique for treating numerical data prior to input into the ESPRIT algorithm for retrieving Laplace components of time series from NMR data (commonly called T-inversion).
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