| 1. |
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
- Mishra, A, et al.
(författare)
-
Diminishing benefits of urban living for children and adolescents' growth and development
- 2023
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 615:7954, s. 874-883
-
Tidskriftsartikel (refereegranskat)abstract
- Optimal growth and development in childhood and adolescence is crucial for lifelong health and well-being1–6. Here we used data from 2,325 population-based studies, with measurements of height and weight from 71 million participants, to report the height and body-mass index (BMI) of children and adolescents aged 5–19 years on the basis of rural and urban place of residence in 200 countries and territories from 1990 to 2020. In 1990, children and adolescents residing in cities were taller than their rural counterparts in all but a few high-income countries. By 2020, the urban height advantage became smaller in most countries, and in many high-income western countries it reversed into a small urban-based disadvantage. The exception was for boys in most countries in sub-Saharan Africa and in some countries in Oceania, south Asia and the region of central Asia, Middle East and north Africa. In these countries, successive cohorts of boys from rural places either did not gain height or possibly became shorter, and hence fell further behind their urban peers. The difference between the age-standardized mean BMI of children in urban and rural areas was <1.1 kg m–2 in the vast majority of countries. Within this small range, BMI increased slightly more in cities than in rural areas, except in south Asia, sub-Saharan Africa and some countries in central and eastern Europe. Our results show that in much of the world, the growth and developmental advantages of living in cities have diminished in the twenty-first century, whereas in much of sub-Saharan Africa they have amplified.
|
|
| 5. |
|
|
| 6. |
- Turcot, Valerie, et al.
(författare)
-
Protein-altering variants associated with body mass index implicate pathways that control energy intake and expenditure in obesity
- 2018
-
Ingår i: Nature Genetics. - : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 50:1, s. 26-41
-
Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies (GWAS) have identified >250 loci for body mass index (BMI), implicating pathways related to neuronal biology. Most GWAS loci represent clusters of common, noncoding variants from which pinpointing causal genes remains challenging. Here we combined data from 718,734 individuals to discover rare and low-frequency (minor allele frequency (MAF) < 5%) coding variants associated with BMI. We identified 14 coding variants in 13 genes, of which 8 variants were in genes (ZBTB7B, ACHE, RAPGEF3, RAB21, ZFHX3, ENTPD6, ZFR2 and ZNF169) newly implicated in human obesity, 2 variants were in genes (MC4R and KSR2) previously observed to be mutated in extreme obesity and 2 variants were in GIPR. The effect sizes of rare variants are similar to 10 times larger than those of common variants, with the largest effect observed in carriers of an MC4R mutation introducing a stop codon (p.Tyr35Ter, MAF = 0.01%), who weighed similar to 7 kg more than non-carriers. Pathway analyses based on the variants associated with BMI confirm enrichment of neuronal genes and provide new evidence for adipocyte and energy expenditure biology, widening the potential of genetically supported therapeutic targets in obesity.
|
|
| 7. |
- Wessel, Jennifer, et al.
(författare)
-
Low-frequency and rare exome chip variants associate with fasting glucose and type 2 diabetes susceptibility
- 2015
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 6
-
Tidskriftsartikel (refereegranskat)abstract
- Fasting glucose and insulin are intermediate traits for type 2 diabetes. Here we explore the role of coding variation on these traits by analysis of variants on the HumanExome BeadChip in 60,564 non-diabetic individuals and in 16,491 T2D cases and 81,877 controls. We identify a novel association of a low-frequency nonsynonymous SNV in GLP1R (A316T; rs10305492; MAF = 1.4%) with lower FG (beta = -0.09 +/- 0.01 mmol l(-1), P = 3.4 x 10(-12)), T2D risk (OR[95% CI] = 0.86[0.76-0.96], P = 0.010), early insulin secretion (beta = -0.07 +/- 0.035 pmol(insulin) mmol(glucose)(-1), P = 0.048), but higher 2-h glucose (beta = 0.16 +/- 0.05 mmol l(-1), P = 4.3 x 10(-4)). We identify a gene-based association with FG at G6PC2 (p(SKAT) = 6.8 x 10(-6)) driven by four rare protein-coding SNVs (H177Y, Y207S, R283X and S324P). We identify rs651007 (MAF = 20%) in the first intron of ABO at the putative promoter of an antisense lncRNA, associating with higher FG (beta = 0.02 +/- 0.004 mmol l(-1), P = 1.3 x 10(-8)). Our approach identifies novel coding variant associations and extends the allelic spectrum of variation underlying diabetes-related quantitative traits and T2D susceptibility.
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
- Marklund, Matti, et al.
(författare)
-
Biomarkers of Dietary Omega-6 Fatty Acids and Incident Cardiovascular Disease and Mortality : An Individual-Level Pooled Analysis of 30 Cohort Studies
- 2019
-
Ingår i: Circulation. - : American Heart Association. - 0009-7322 .- 1524-4539. ; 139:21, s. 2422-2436
-
Tidskriftsartikel (refereegranskat)abstract
- Background:Global dietary recommendations for and cardiovascular effects of linoleic acid, the major dietary omega-6 fatty acid, and its major metabolite, arachidonic acid, remain controversial. To address this uncertainty and inform international recommendations, we evaluated how in vivo circulating and tissue levels of linoleic acid (LA) and arachidonic acid (AA) relate to incident cardiovascular disease (CVD) across multiple international studies.Methods:We performed harmonized, de novo, individual-level analyses in a global consortium of 30 prospective observational studies from 13 countries. Multivariable-adjusted associations of circulating and adipose tissue LA and AA biomarkers with incident total CVD and subtypes (coronary heart disease, ischemic stroke, cardiovascular mortality) were investigated according to a prespecified analytic plan. Levels of LA and AA, measured as the percentage of total fatty acids, were evaluated linearly according to their interquintile range (ie, the range between the midpoint of the first and fifth quintiles), and categorically by quintiles. Study-specific results were pooled using inverse-variance-weighted meta-analysis. Heterogeneity was explored by age, sex, race, diabetes mellitus, statin use, aspirin use, omega-3 levels, and fatty acid desaturase 1 genotype (when available).Results:In 30 prospective studies with medians of follow-up ranging 2.5 to 31.9 years, 15198 incident cardiovascular events occurred among 68659 participants. Higher levels of LA were significantly associated with lower risks of total CVD, cardiovascular mortality, and ischemic stroke, with hazard ratios per interquintile range of 0.93 (95% CI, 0.88-0.99), 0.78 (0.70-0.85), and 0.88 (0.79-0.98), respectively, and nonsignificantly with lower coronary heart disease risk (0.94; 0.88-1.00). Relationships were similar for LA evaluated across quintiles. AA levels were not associated with higher risk of cardiovascular outcomes; in a comparison of extreme quintiles, higher levels were associated with lower risk of total CVD (0.92; 0.86-0.99). No consistent heterogeneity by population subgroups was identified in the observed relationships.Conclusions:In pooled global analyses, higher in vivo circulating and tissue levels of LA and possibly AA were associated with lower risk of major cardiovascular events. These results support a favorable role for LA in CVD prevention.
|
|
| 11. |
- White, H, et al.
(författare)
-
A certified plasmid reference material for the standardisation of BCR-ABL1 mRNA quantification by real time quantitative PCR.
- 2015
-
Ingår i: Leukemia. - : Springer Science and Business Media LLC. - 1476-5551 .- 0887-6924. ; 29:2, s. 369-376
-
Tidskriftsartikel (refereegranskat)abstract
- Serial quantification of BCR-ABL1 mRNA is an important therapeutic indicator in chronic myeloid leukemia, but there is substantial variation in results reported by different laboratories. To improve comparability, an internationally accepted plasmid certified reference material (CRM) was developed according to ISO Guide 34:2009. Fragments of BCR-ABL1 (e14a2 mRNA fusion), BCR and GUSB transcripts were amplified and cloned into pUC18 to yield plasmid pIRMM0099. Six different linearised plasmid solutions were produced with the following copy number concentrations, assigned by digital PCR, and expanded uncertainties: 1.08±0.13 × 10(6), 1.08±0.11 × 10(5), 1.03±0.10 × 10(4), 1.02±0.09 × 10(3), 1.04±0.10 × 10(2) and 10.0±1.5 copies/μL. The certification of the material for the number of specific DNA fragments per plasmid, copy number concentration of the plasmid solutions and the assessment of inter-unit heterogeneity and stability were performed according to ISO Guide 35:2006. Two suitability studies performed by 63 BCR-ABL1 testing laboratories demonstrated that this set of 6 plasmid CRMs can help to standardise the numbers of measured transcripts of e14a2 BCR-ABL1 and three control genes; ABL1, BCR and GUSB. The set of 6 plasmid CRMs is distributed worldwide by the Institute for Reference Materials and Measurements (Belgium) and its authorised distributors (http://irmm.jrc.ec.europa.eu; CRM code ERM-AD623a-f).Leukemia accepted article preview online, 18 July 2014; doi:10.1038/leu.2014.217.
|
|
| 12. |
- Kilpeläinen, Tuomas O, et al.
(författare)
-
Genetic variation near IRS1 associates with reduced adiposity and an impaired metabolic profile.
- 2011
-
Ingår i: Nature genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 43:8, s. 753-60
-
Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies have identified 32 loci influencing body mass index, but this measure does not distinguish lean from fat mass. To identify adiposity loci, we meta-analyzed associations between ∼2.5 million SNPs and body fat percentage from 36,626 individuals and followed up the 14 most significant (P < 10(-6)) independent loci in 39,576 individuals. We confirmed a previously established adiposity locus in FTO (P = 3 × 10(-26)) and identified two new loci associated with body fat percentage, one near IRS1 (P = 4 × 10(-11)) and one near SPRY2 (P = 3 × 10(-8)). Both loci contain genes with potential links to adipocyte physiology. Notably, the body-fat-decreasing allele near IRS1 is associated with decreased IRS1 expression and with an impaired metabolic profile, including an increased visceral to subcutaneous fat ratio, insulin resistance, dyslipidemia, risk of diabetes and coronary artery disease and decreased adiponectin levels. Our findings provide new insights into adiposity and insulin resistance.
|
|
| 13. |
- Speliotes, Elizabeth K, et al.
(författare)
-
Genome-wide association analysis identifies variants associated with nonalcoholic fatty liver disease that have distinct effects on metabolic traits.
- 2011
-
Ingår i: PLoS genetics. - : Public Library of Science (PLoS). - 1553-7404. ; 7:3
-
Tidskriftsartikel (refereegranskat)abstract
- Nonalcoholic fatty liver disease (NAFLD) clusters in families, but the only known common genetic variants influencing risk are near PNPLA3. We sought to identify additional genetic variants influencing NAFLD using genome-wide association (GWA) analysis of computed tomography (CT) measured hepatic steatosis, a non-invasive measure of NAFLD, in large population based samples. Using variance components methods, we show that CT hepatic steatosis is heritable (∼26%-27%) in family-based Amish, Family Heart, and Framingham Heart Studies (n=880 to 3,070). By carrying out a fixed-effects meta-analysis of genome-wide association (GWA) results between CT hepatic steatosis and ∼2.4 million imputed or genotyped SNPs in 7,176 individuals from the Old Order Amish, Age, Gene/Environment Susceptibility-Reykjavik study (AGES), Family Heart, and Framingham Heart Studies, we identify variants associated at genome-wide significant levels (p<5×10(-8)) in or near PNPLA3, NCAN, and PPP1R3B. We genotype these and 42 other top CT hepatic steatosis-associated SNPs in 592 subjects with biopsy-proven NAFLD from the NASH Clinical Research Network (NASH CRN). In comparisons with 1,405 healthy controls from the Myocardial Genetics Consortium (MIGen), we observe significant associations with histologic NAFLD at variants in or near NCAN, GCKR, LYPLAL1, and PNPLA3, but not PPP1R3B. Variants at these five loci exhibit distinct patterns of association with serum lipids, as well as glycemic and anthropometric traits. We identify common genetic variants influencing CT-assessed steatosis and risk of NAFLD. Hepatic steatosis associated variants are not uniformly associated with NASH/fibrosis or result in abnormalities in serum lipids or glycemic and anthropometric traits, suggesting genetic heterogeneity in the pathways influencing these traits.
|
|
| 14. |
- Engeset, Dagrun, et al.
(författare)
-
Fish consumption and mortality in the European Prospective Investigation into Cancer and Nutrition cohort
- 2015
-
Ingår i: European Journal of Epidemiology. - : Springer Science and Business Media LLC. - 1573-7284 .- 0393-2990. ; 30:1, s. 57-70
-
Tidskriftsartikel (refereegranskat)abstract
- Fish is a source of important nutrients and may play a role in preventing heart diseases and other health outcomes. However, studies of overall mortality and cause-specific mortality related to fish consumption are inconclusive. We examined the rate of overall mortality, as well as mortality from ischaemic heart disease and cancer in relation to the intake of total fish, lean fish, and fatty fish in a large prospective cohort including ten European countries. More than 500,000 men and women completed a dietary questionnaire in 1992-1999 and were followed up for mortality until the end of 2010. 32,587 persons were reported dead since enrolment. Hazard ratios and their 99 % confidence interval were estimated using Cox proportional hazard regression models. Fish consumption was examined using quintiles based on reported consumption, using moderate fish consumption (third quintile) as reference, and as continuous variables, using increments of 10 g/day. All analyses were adjusted for possible confounders. No association was seen for fish consumption and overall or cause-specific mortality for both the categorical and the continuous analyses, but there seemed to be a U-shaped trend (p < 0.000) with fatty fish consumption and total mortality and with total fish consumption and cancer mortality (p = 0.046).
|
|
| 15. |
- Ricci, Cristian, et al.
(författare)
-
Alcohol intake in relation to non-fatal and fatal coronary heart disease and stroke : EPIC-CVD case-cohort study
- 2018
-
Ingår i: The BMJ. - : BMJ PUBLISHING GROUP. - 1756-1833 .- 0959-8138. ; 361
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE To investigate the association between alcohol consumption (at baseline and over lifetime) and non-fatal and fatal coronary heart disease (CHD) and stroke. DESIGN Multicentre case-cohort study. SETTING A study of cardiovascular disease (CVD) determinants within the European Prospective Investigation into Cancer and nutrition cohort (EPIC-CVD) from eight European countries. PARTICIPANTS 32 549 participants without baseline CVD, comprised of incident CVD cases and a subcohort for comparison. MAIN OUTCOME MEASURES Non-fatal and fatal CHD and stroke (including ischaemic and haemorrhagic stroke). RESULTS There were 9307 non-fatal CHD events, 1699 fatal CHD, 5855 non-fatal stroke, and 733 fatal stroke. Baseline alcohol intake was inversely associated with non-fatal CHD, with a hazard ratio of 0.94 (95% confidence interval 0.92 to 0.96) per 12 g/day higher intake. There was a J shaped association between baseline alcohol intake and risk of fatal CHD. The hazard ratios were 0.83 (0.70 to 0.98), 0.65 (0.53 to 0.81), and 0.82 (0.65 to 1.03) for categories 5.0-14.9 g/day, 15.0-29.9 g/day, and 30.0-59.9 g/day of total alcohol intake, respectively, compared with 0.1-4.9 g/ day. In contrast, hazard ratios for non-fatal and fatal stroke risk were 1.04 (1.02 to 1.07), and 1.05 (0.98 to 1.13) per 12 g/day increase in baseline alcohol intake, respectively, including broadly similar findings for ischaemic and haemorrhagic stroke. Associations with cardiovascular outcomes were broadly similar with average lifetime alcohol consumption as for baseline alcohol intake, and across the eight countries studied. There was no strong evidence for interactions of alcohol consumption with smoking status on the risk of CVD events. CONCLUSIONS Alcohol intake was inversely associated with non-fatal CHD risk but positively associated with the risk of different stroke subtypes. This highlights the opposing associations of alcohol intake with different CVD types and strengthens the evidence for policies to reduce alcohol consumption.
|
|
| 16. |
- Ewerlof, M., et al.
(författare)
-
Analysis of the Auditory Perception of Ultrasound Doppler Signals to Improve Pregnancy Risk Assessment
- 2011
-
Ingår i: 15th Nordic-Baltic Conference on Biomedical Engineering and Medical Physics (IFMBE Proceedings). - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1680-0737. ; 34, s. 81-84
-
Konferensbidrag (refereegranskat)abstract
- In high-risk pregnancies, the transport of oxygen and nutrients from maternal to fetal blood via the placenta is often impaired. To assess the risk, pulsed Doppler ultrasound (US) is used to evaluate the flow velocity waveform in the umbilical artery with the pulsatility index (PI), which is derived from the velocity envelope of the Doppler power spectrum. However, simply listening to the Doppler signal can indicate to an experienced sonographer that the type of the blood flow is worse than the PI suggests. This is however dependent on the operator's experience and it may be difficult to estimate what influences the subjective judgement. Motivated by the description of the Doppler sounds by an experienced operator (AT) as having a "timbre", this study describes an analysis of Doppler sounds in search for an index or method with capacity to better evaluate the blood flow in the umbilical artery in high-risk pregnancies. A test was designed, where synthetically produced Doppler sounds with various spectral contents were played together with a variable sinusoidal sound signal. The task for the five test persons was to match the frequency of the sinusoidal signal to the Doppler sounds. The tests indicated that the human ear is most sensitive to the lower frequencies of Doppler sounds. An analysis of prerecorded sounds showed a difference in the lower frequencies of a sound considered to emanate from the umbilical blood flow of healthy fetuses with normally functioning placenta as compared to a pathological one. This might explain the difference between the sounds experienced by an operator. As a suggestion to extract more information than the maximum envelope, the minimum frequency envelope was extracted from pre-recorded clinical sounds. Based on the pilot tests presented here, this shows to be a promising strategy.
|
|
| 17. |
- Hansen, Ida R., et al.
(författare)
-
Contrasting effects of cold acclimation versus obesogenic diets on chemerin gene expression in brown and brite adipose tissues
- 2014
-
Ingår i: Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids. - : Elsevier BV. - 1388-1981 .- 1879-2618. ; 1841:12, s. 1691-1699
-
Tidskriftsartikel (refereegranskat)abstract
- Based on results from a signal sequence trap, we investigated chemerin gene expression in brown adipose tissue. Male NMRI mice were exposed to 30, 22 or 4 degrees C for 3 weeks, or were fed control (chow) diet, cafeteria diet or high-fat diet at thermoneutrality for the same time. In brown adipose tissue, cold acclimation strongly diminished chemerin gene expression, whereas obesogenic diets augmented expression. Qualitatively, changes in expression were paralleled in brite/beige adipose tissues (e.g. inguinal), whereas white adipose tissue (epididymal) and muscle did not react to these cues. Changes in tissue expression were not directly paralleled by alterations in plasma levels. Both these intact animal studies and brown adipocyte cell culture studies indicated that the gene expression regulation was not congruent with a sympathetic/adrenergic control. The data are discussed in relation to suggested endocrine, paracrine and autocrine effects of chemerin.
|
|
| 18. |
- Hessérus, Mattias, 1977-
(författare)
-
Rätten till privatlivet : och moralen bakom omoralen i svensk press 1920 – 1980
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis examines the development of the notion of the right to privacy in Sweden between 1920 and 1980. The formation of the notion of the right to privacy is studied through the debate concerning exposure of the aspect of privacy that can be considered the most sensitive: the individual’s sex life and intimate relations.The theoretical framework is based on the sociologist Ferdinand Tönnies’ concepts of Gemeinschaft and Gesellschaft (community and association). The thesis pays particular attention to privacy in relation to the development of the “media society” during the 20th century.Three significant shifts in the Swedish history of privacy during the 20th century are identified and examined: The boycott of the muck-raking paper Fäderneslandet (“The Fatherland”) in 1927, the introduction of “the sanctity of private life” in the rules of the Swedish Publicists’ Association in 1953 and the appointment of the Integrity Protection Committee in 1966.Key findings are: The notion of right to privacy in Sweden evolves in four phases: The first phase (1920 – 1953) is characterized by a paradoxical relationship to privacy following the division between “decent” and “indecent”. “Decent people” had the right to a private sphere while “indecent people” were deprived of privacy. After a viscous hunt of homosexuals in the press, in the late 1940’s, the second phase (1953 – 1964) is defined by liberalisation of the decency concept and a more restrictive press policy as regards exposure of private details relating to sexuality.A modern-day notion of right to privacy is, however, not visible in Sweden until the third phase (1964 – 1975). Yet, the fourth phase (1975 – 1980) is characterised by a backlash. Under the slogan of “the private is political” young radicals and second-wave feminists questioned the privacy concept and saw the right to privacy as a threat to community and equality. Attempts to create privacy legislation in Sweden failed due to unwillingness by the government to recognize the rights of the individual over the rights of the community.Conflicting notions of Gemeinschaft and Gesellschaft within society partly explains the shifting status of the right to privacy in Sweden 1920 – 1980.
|
|
| 19. |
- Johansson, Kristina, et al.
(författare)
-
Von Willebrand factor, ABO blood group, and risk of first-ever intracerebral hemorrhage : A prospective nested case-control study
- 2020
-
Ingår i: Thrombosis Research. - : Elsevier. - 0049-3848 .- 1879-2472. ; 195, s. 77-80
-
Tidskriftsartikel (refereegranskat)abstract
- Background and purpose: Low levels of von Willebrand factor (VWF) were associated with intracerebral hemorrhage (ICH) in a previous study. Persons with blood group O have lower VWF levels than other ABO blood groups. This study aimed to investigate the association between VWF and the risk of ICH in adults, as well as the association between ABO blood group and risk of ICH.Methods: This population-based, nested case-control study was conducted using data and blood samples from health examinations between 1985 and 2007. All participants were followed, and cases with first-ever ICH were identified and validated. One or two controls were matched to each case.Results: During a median follow-up time from blood sampling to ICH of 5.6 years, 176 cases with ICH were identified. The mean age at health examination was 57 years; 50% of participants were women. There was an association between hypertension and risk of ICH, but there was no association between VWF level and risk of ICH. There was no association between blood group O and risk of ICH.Conclusions: To our knowledge this is the largest prospective study investigating the association between VWF, ABO blood group and ICH. We found no association between VWF or blood group O and risk of future ICH.
|
|
| 20. |
- Lopez-Ferreras, Lorena, et al.
(författare)
-
The supramammillary nucleus controls anxiety-like behavior; key role of GLP-1R
- 2020
-
Ingår i: Psychoneuroendocrinology. - : Elsevier BV. - 0306-4530. ; 119:September
-
Tidskriftsartikel (refereegranskat)abstract
- Anxiety disorders are among the most prevalent categories of mental illnesses. The gut-brain axis, along with gastrointestinally-derived neuropeptides, like glucagon-like peptide-1 (GLP-1), are emerging as potential key regulators of emotionality, including anxiety behavior. However, the neuroanatomical substrates from which GLP-1 exerts its anxiogenic effect remain poorly characterized. Here we focus on a relatively new candidate nucleus, the supramammillary nucleus (SuM), located just caudal to the lateral hypothalamus and ventral to the ventral tegmental area. Our focus on the SuM is supported by previous data showing expression of GLP-1R mRNA throughout the SuM and activation of the SuM during anxiety-inducing behaviors in rodents. Data show that chemogenetic activation of neurons in the SuM results in an anxiolytic response in male and female rats. In contrast, selective activation of SuM GLP-1R, by microinjection of a GLP-1R agonist exendin-4 into the SuM resulted in potent anxiety-like behavior, measured in both open field and elevated plus maze tests in male and female rats. This anxiogenic effect of GLP-1R activation persisted after high-fat diet exposure. Importantly, reduction of GLP-1R expression in the SuM, by AAV-shRNA GLP-1R knockdown, resulted in a clear anxiolytic response; an effect only observed in female rats. Our data identify a new neural substrate for GLP-1 control of anxiety-like behavior and indicate that the SuM GLP-1R are sufficient for anxiogenesis in both sexes, but necessary only in females.
|
|
| 21. |
- Stehr, Jan Eric, et al.
(författare)
-
Magneto-optical properties of Cr3+ in beta-Ga2O3
- 2021
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 119:5
-
Tidskriftsartikel (refereegranskat)abstract
- beta-Ga2O3 is a wide bandgap semiconductor that is attractive for various applications, including power electronics and transparent conductive electrodes. Its properties can be strongly affected by transition metal impurities commonly present during the growth such as Cr. In this Letter, we determine the electronic structure of Cr3+ by performing a correlative study of magneto-photoluminescence (magneto-PL) and electron paramagnetic resonance. We unambiguously prove that the so-called R-1 and R-2 PL lines at around 1.79eV originate from an internal transition between the first excited state (E-2) and the (4)A(2) ground state of Cr3+. The center is concluded to have monoclinic local symmetry and exhibits a large zero-field splitting (similar to 147 mu eV) of the ground state, which can be directly measured from the fine structure of the R1 transition. Furthermore, g-values of the first excited state are accurately determined as g(a) = 1.7, g(b) = 1.5, and g(c*) = 2.1. Our results advance our understanding of the electronic structure of Cr in beta-Ga2O3 and provide a spectroscopic signature of this common residual impurity. (C) 2021 Author(s).
|
|
