| 1. |
- Alenaini, Wareed, et al.
(författare)
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Ethnic Differences in Body Fat Deposition and Liver Fat Content in Two UK‐Based Cohorts
- 2020
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Ingår i: Obesity. - : John Wiley & Sons. - 1930-7381 .- 1930-739X. ; 28:11, s. 2142-2152
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveDifferences in the content and distribution of body fat and ectopic lipids may be responsible for ethnic variations in metabolic disease susceptibility. The aim of this study was to examine the ethnic distribution of body fat in two separate UK‐based populations.MethodsAnthropometry and body composition were assessed in two separate UK cohorts: the Hammersmith cohort and the UK Biobank, both comprising individuals of South Asian descent (SA), individuals of Afro‐Caribbean descent (AC), and individuals of European descent (EUR). Regional adipose tissue stores and liver fat were measured by magnetic resonance techniques.ResultsThe Hammersmith cohort (n = 747) had a mean (SD) age of 41.1 (14.5) years (EUR: 374 men, 240 women; SA: 68 men, 22 women; AC: 14 men, 29 women), and the UK Biobank (n = 9,533) had a mean (SD) age of 55.5 (7.5) years (EUR: 4,483 men, 4,873 women; SA: 80 men, 43 women, AC: 31 men, 25 women). Following adjustment for age and BMI, no significant differences in visceral adipose tissue or liver fat were observed between SA and EUR individuals in the either cohort.ConclusionsOur data, consistent across two independent UK‐based cohorts, present a limited number of ethnic differences in the distribution of body fat depots associated with metabolic disease. These results suggest that the ethnic variation in susceptibility to features of the metabolic syndrome may not arise from differences in body fat.
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| 2. |
- Kovács, András, et al.
(författare)
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Role of heterophase interfaces on local coercivity mechanisms in the magnetic Al0.3CoFeNi complex concentrated alloy
- 2023
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Ingår i: Acta Materialia. - : Elsevier BV. - 1359-6454. ; 246
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Tidskriftsartikel (refereegranskat)abstract
- Microstructural features across different length scales have a profound influence on the coercivity of magnetic alloys. Whereas the role of homophase boundaries on the pinning of magnetic domain walls is well established, the influence of heterophase interfaces on domain wall motion is complex and poorly understood. Here, we use state-of-the-art electron microscopy techniques to show that the magnetization reversal process in an Al0.3CoFeNi magnetic complex concentrated alloy (CCA), which is responsible for its coercivity, changes dramatically from a nucleation-type mechanism in the FCC+L12 state of the CCA, with a domain wall width of 171 nm, to a pinning type mechanism in the microstructure with colonies of FCC/L12 nanorods embedded in a BCC/B2 matrix, with a domain wall width of 35 nm. Our work reveals that heterophase FCC/BCC interfaces have a much stronger effect on coercivity than isostructural chemically ordered/disordered interfaces and provides a powerful guide to the rational design of microstructure to tune magnetic properties in both complex concentrated alloys and conventional magnetic alloys.
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| 3. |
- Liu, Xiongjun, et al.
(författare)
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Metastable high entropy alloys
- 2022
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 120:12
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- High entropy alloys (HEAs) are a new family of alloys usually made up of five or more metallic elements in approximately equal proportions to maximize the configurational entropy, also termed as the multi-principal-element alloys or complex concentrated alloys. The unique features of structure and property render HEAs exciting potential for structural and functional applications, particularly for those cases under extreme conditions, which spark intense research activities in this area, ranging from the fundamental issues, such as phase formation and stability, to the engineering-related problems, such as fabrication, processing, and usage performance. HEAs are the focus of intense research in the fields of materials science and condensed matter physics. Compositional metastability in HEAs leads to decomposition of the complex concentrated solid solution via thermally activated processes, which results in the development of local chemical ordering, the precipitation of second phases, and the formation of a complex multi-phase microstructure.
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| 4. |
- Parisinos, Constantinos A., et al.
(författare)
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Genome-wide and Mendelian randomisation studies of liver MRI yield insights into the pathogenesis of steatohepatitis
- 2020
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Ingår i: Journal of Hepatology. - : Elsevier. - 0168-8278 .- 1600-0641. ; 73:2, s. 241-251
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundA non-invasive method to grade the severity of steatohepatitis and liver fibrosis is magnetic resonance imaging (MRI) based corrected T1 (cT1). We aimed to identify genetic variants influencing liver cT1 and use genetics to understand mechanisms underlying liver fibroinflammatory disease and its link with other metabolic traits and diseases.MethodsFirst, we performed a genome-wide association study (GWAS) in 14,440 Europeans in UK Biobank with liver cT1 measures. Second, we explored the effects of the cT1 variants on liver blood tests, and a range of metabolic traits and diseases. Third, we used Mendelian randomisation to test the causal effects of 24 predominantly metabolic traits on liver cT1 measures.ResultsWe identified six independent genetic variants associated with liver cT1 that reached GWAS significance threshold (p<5x10-8). Four of the variants (rs75935921 in SLC30A10, rs13107325 in SLC39A8, rs58542926 in TM6SF2, rs738409 in PNPLA3) were also associated with elevated transaminases and had variable effects on liver fat and other metabolic traits. Insulin resistance, type 2 diabetes, non-alcoholic fatty liver and BMI were causally associated with elevated cT1 whilst favourable adiposity (instrumented by variants associated with higher adiposity but lower risk of cardiometabolic disease and lower liver fat) was found to be protective.ConclusionThe association between two metal ion transporters and cT1 indicates an important new mechanism in steatohepatitis. Future studies are needed to determine whether interventions targeting the identified transporters might prevent liver disease in at risk individuals.
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| 5. |
- Pavlides, Michael, et al.
(författare)
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Liver investigation: Testing marker utility in steatohepatitis (LITMUS): Assessment & validation of imaging modality performance across the NAFLD spectrum in a prospectively recruited cohort study (the LITMUS imaging study): Study protocol
- 2023
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Ingår i: Contemporary Clinical Trials. - : ELSEVIER SCIENCE INC. - 1551-7144 .- 1559-2030. ; 134
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Tidskriftsartikel (refereegranskat)abstract
- Non-alcoholic fatty liver disease (NAFLD) is the liver manifestation of the metabolic syndrome with global prevalence reaching epidemic levels. Despite the high disease burden in the population only a small proportion of those with NAFLD will develop progressive liver disease, for which there is currently no approved pharmacotherapy. Identifying those who are at risk of progressive NAFLD currently requires a liver biopsy which is problematic. Firstly, liver biopsy is invasive and therefore not appropriate for use in a condition like NAFLD that affects a large proportion of the population. Secondly, biopsy is limited by sampling and observer dependent variability which can lead to misclassification of disease severity. Non-invasive biomarkers are therefore needed to replace liver biopsy in the assessment of NAFLD. Our study addresses this unmet need. The LITMUS Imaging Study is a prospectively recruited multi-centre cohort study evaluating magnetic resonance imaging and elastography, and ultrasound elastography against liver histology as the reference standard. Imaging biomarkers and biopsy are acquired within a 100-day window. The study employs standardised processes for imaging data collection and analysis as well as a real time central monitoring and quality control process for all the data submitted for analysis. It is anticipated that the high-quality data generated from this study will underpin changes in clinical practice for the benefit of people with NAFLD. Study Registration: clinicaltrials.gov: NCT05479721
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| 6. |
- Teo, Kevin, et al.
(författare)
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rs641738C>T near MBOAT7 is associated with liver fat, ALT, and fibrosis in NAFLD: a meta-analysis.
- 2021
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Ingår i: Journal of hepatology. - : Elsevier BV. - 1600-0641 .- 0168-8278. ; 74:1, s. 20-30
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Tidskriftsartikel (refereegranskat)abstract
- A common genetic variant near MBOAT7 (rs641738C>T) has been previously associated with hepatic fat and advanced histology in non-alcoholic fatty liver disease (NAFLD), however, these findings have not been consistently replicated in the literature. We aimed to establish whether rs641738C>T is a risk factor across the spectrum of NAFLD and characterize its role in the regulation of related metabolic phenotypes through meta-analysis.We performed meta-analysis of studies with data on the association between rs641738C>T genotype and: liver fat, NAFLD histology, and serum ALT, lipids, or insulin. These included directly genotyped studies and population-level data from genome-wide association studies (GWAS). We performed random effects meta-analysis using recessive, additive, and dominant genetic models.Data from 1,066,175 participants (9,688 with liver biopsies) across 42 studies were included in the meta-analysis. rs641738C>T was associated with higher liver fat on CT/MRI (+0.03 standard deviations [95% CI: 0.02 - 0.05], pz=4.8x10-5) and diagnosis of NAFLD (OR 1.17 [95% CI 1.05 - 1.3], pz=0.003) in Caucasian adults. The variant was also positively associated with presence of advanced fibrosis (OR 1.22 [95% CI: 1.03 - 1.45], pz=0.021) in Caucasian adults using a recessive model of inheritance (CC+CT vs. TT). Meta-analysis of data from previous GWAS found the variant to be associated with higher ALT (pz=0.002) and lower serum triglycerides (pz=1.5x10-4). rs641738C>T was not associated with fasting insulin and no effect was observed in children with NAFLD.Our study validates rs641738C>T near MBOAT7 as a risk factor for the presence and severity of NAFLD in individuals of European descent.
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| 7. |
- Varahabhatla, S. M., et al.
(författare)
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Influence of annealing on enhancing soft magnetic properties in laser powder bed fusion processed Hiperco (Fe-49Co-2V)
- 2024
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Ingår i: Additive Manufacturing Letters. - 2772-3690. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Annealing of laser powder bed fusion (LPBF) processed Fe-49Co-2 V (Hiperco) samples at 865 °C for 4 h leads to a substantial improvement in its soft magnetic properties. While the as built LPBF samples exhibited relatively higher coercivities (Hc) ranging from 25.8 – 26.5 Oe, the annealed LPBF samples showed significantly lower coercivities (Hc) of 6.9 – 10.8 Oe. These lower Hc values can not only be attributed to the 15–20 times larger grain sizes, but also the higher degree of B2 ordering in the annealed condition. The enhanced degree of B2 ordering also increases the saturation magnetization (Ms), from 213 to 228 emu/g, in samples processed with a laser fluence (energy/density) of 3.4 J/mm2. These results reveal the underlying mechanisms leading to an enhancement of soft magnetic properties in LPBF processed Hiperco via annealing-induced microstructural control.
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| 8. |
- Varahabhatla, S. M., et al.
(författare)
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Influence of energy density on the microstructure, growth orientation, and anisotropy of magnetic properties in additively manufactured Fe-3.8wt%Si transformer steels
- 2023
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Ingår i: Materialia. - 2589-1529. ; 30
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Tidskriftsartikel (refereegranskat)abstract
- Fe-3.8wt%Si transformer steels were processed using two different additive manufacturing (AM) techniques, laser powder bed fusion (LPBF) and directed energy deposition (DED). While the LPBF processed samples exhibited a strong <001> orientation of the BCC grains along the build axis, the DED processed samples exhibited a randomized texture along the build axis. DED processed samples showed substantially coarser columnar grains as compared to their LPBF counterparts. The columnar grains exhibited a substantial number of low-angle sub-grain boundaries. All samples exhibited very good soft magnetic properties, with saturation magnetization (Ms) values ranging from 205 - 232 emu/gm, and coercivity (Hc) values ranging from 1.2 – 4.2 Oe. The Coercivity (Hc) values were significantly lower when the magnetic field was applied parallel to the build axis, as compared to being perpendicular, which can be rationalized based on the columnar nature of the grains, resulting in a higher number density of grain boundaries in case of the field applied perpendicular to the build axis.
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