| 1. |
- Abbas, Syed Adeel, et al.
(författare)
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Spinel-type Na2MoO4 and Na2WO4 as promising optoelectronic materials : First-principle DFT calculations
- 2020
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Ingår i: Chemical Physics. - : Elsevier. - 0301-0104 .- 1873-4421. ; 538
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Tidskriftsartikel (refereegranskat)abstract
- The mechanical, thermodynamic, electronic, and optical properties of Na2MoO4 (NMO) and Na2WO4 (NWO) spinels are elaborated by density functional theory (DFT) based full potential augmented plane wave method (FP-LAPW + lo). Our optimized lattice constants for the studied spinels are in good agreement with that obtained experimentally. The enthalpy of formation ensures the thermodynamic stability of NMO and NWO in the cubic phase. The Born mechanical stability criteria guarantees their mechanical stability, while Poisson ratio (ν) and Pugh's ratio (B/G) infer their brittle behavior. The Debye temperature (θD) is significant for NMO than NWO. The wide bandgap of 3.5 eV for NMO and 4.4 eV for NWO show the maximum absorption in the ultraviolet region that increases their importance for optoelectronic applications. The optical properties are explained in term of dielectric constant, refractive index, absorption of light, reflection, and optical loss factor.
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| 2. |
- Agius, Stephanie C, et al.
(författare)
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NAD(P) turnover in plant mitochondria
- 2001
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Ingår i: Australian Journal of Plant Physiology. - 0310-7841. ; 28:6, s. 461-470
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Tidskriftsartikel (refereegranskat)abstract
- An analytical procedure based on alkaline extraction and HPLC analysis was adapted for quantification of pyridine nucleotides in plant mitochondria. The amounts of NAD and NADP extracted from seven different species varied from 1.0 to 3.7 and 0 to 0.5 nmol (mg protein) –1 , respectively. Although NADP was found in four species, its reduced form was in all cases below the detection limit of 0.1 nmol (mg protein) –1 . The NAD pool was mainly oxidized in the absence of substrates. However, oxidation of substrates followed by anaerobiosis caused 50–92% NAD pool reduction, indicating that the majority of the NAD+ was metabolically active. The NAD reduction level in potato tuber mitochondria oxidizing malate varied with assay conditions. The highest level of reduction (>80%) was reached at anaerobiosis, at pH 6.5 and 7.2, conditions favouring malic enzyme (ME), whereas the lowest reduction level (0%) was observed at pH 7.5, conditions favouring malate dehydrogenase (MDH). Mitochondria incubated at 0°C without respiratory substrate showed a loss of endogenous NAD + which correlated with a decline in the rate of oxidation of NAD+ -linked substrates. The lost NAD+ was mainly recovered as breakdown products in both the surrounding medium and the mitochondria. When submitochondrial fractions were incubated with NAD + or NADP + , the highest rate of NAD(P)+metabolism was detected in the outer membrane fraction. The metabolites detected, adenosine monophosphate (AMP), nicotinamide mononucleotide (NMN) and adenosine, imply that several enzymes involved in pyridine nucleotide degradation, including an NAD pyrophosphatase, are localized to the outer membrane.
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| 3. |
- Aglago, Elom K., et al.
(författare)
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A Genetic Locus within the FMN1/GREM1 Gene Region Interacts with Body Mass Index in Colorectal Cancer Risk
- 2023
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Ingår i: Cancer Research. - : American Association For Cancer Research (AACR). - 0008-5472 .- 1538-7445. ; 83:15, s. 2572-2583
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Tidskriftsartikel (refereegranskat)abstract
- Colorectal cancer risk can be impacted by genetic, environmental, and lifestyle factors, including diet and obesity. Gene-environment interactions (G × E) can provide biological insights into the effects of obesity on colorectal cancer risk. Here, we assessed potential genome-wide G × E interactions between body mass index (BMI) and common SNPs for colorectal cancer risk using data from 36,415 colorectal cancer cases and 48,451 controls from three international colorectal cancer consortia (CCFR, CORECT, and GECCO). The G × E tests included the conventional logistic regression using multiplicative terms (one degree of freedom, 1DF test), the two-step EDGE method, and the joint 3DF test, each of which is powerful for detecting G × E interactions under specific conditions. BMI was associated with higher colorectal cancer risk. The two-step approach revealed a statistically significant G×BMI interaction located within the Formin 1/Gremlin 1 (FMN1/GREM1) gene region (rs58349661). This SNP was also identified by the 3DF test, with a suggestive statistical significance in the 1DF test. Among participants with the CC genotype of rs58349661, overweight and obesity categories were associated with higher colorectal cancer risk, whereas null associations were observed across BMI categories in those with the TT genotype. Using data from three large international consortia, this study discovered a locus in the FMN1/GREM1 gene region that interacts with BMI on the association with colorectal cancer risk. Further studies should examine the potential mechanisms through which this locus modifies the etiologic link between obesity and colorectal cancer.SIGNIFICANCE: This gene-environment interaction analysis revealed a genetic locus in FMN1/GREM1 that interacts with body mass index in colorectal cancer risk, suggesting potential implications for precision prevention strategies.
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| 4. |
- Aglago, Elom K., et al.
(författare)
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Dietary Advanced Glycation End-Products and Colorectal Cancer Risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) Study
- 2021
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Ingår i: Nutrients. - : MDPI. - 2072-6643. ; 13:9
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Tidskriftsartikel (refereegranskat)abstract
- Dietary advanced glycation end-products (dAGEs) have been hypothesized to be associated with a higher risk of colorectal cancer (CRC) by promoting inflammation, metabolic dysfunction, and oxidative stress in the colonic epithelium. However, evidence from prospective cohort studies is scarce and inconclusive. We evaluated CRC risk associated with the intake of dAGEs in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Dietary intakes of three major dAGEs: Nε-carboxy-methyllysine (CML), Nε-carboxyethyllysine (CEL), and Nδ-(5-hydro-5-methyl-4-imidazolon-2-yl)-ornithine (MG-H1) were estimated in 450,111 participants (median follow-up = 13 years, with 6162 CRC cases) by matching to a detailed published European food composition database. Hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations of dAGEs with CRC were computed using multivariable-adjusted Cox regression models. Inverse CRC risk associations were observed for CML (HR comparing extreme quintiles: HRQ5vs.Q1 = 0.92, 95% CI = 0.85-1.00) and MG-H1 (HRQ5vs.Q1 = 0.92, 95% CI = 0.85-1.00), but not for CEL (HRQ5vs.Q1 = 0.97, 95% CI = 0.89-1.05). The associations did not differ by sex or anatomical location of the tumor. Contrary to the initial hypothesis, our findings suggest an inverse association between dAGEs and CRC risk. More research is required to verify these findings and better differentiate the role of dAGEs from that of endogenously produced AGEs and their precursor compounds in CRC development.
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| 5. |
- Agudelo, LZ, et al.
(författare)
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Skeletal muscle PGC-1α1 reroutes kynurenine metabolism to increase energy efficiency and fatigue-resistance
- 2019
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Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1, s. 2767-
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Tidskriftsartikel (refereegranskat)abstract
- The coactivator PGC-1α1 is activated by exercise training in skeletal muscle and promotes fatigue-resistance. In exercised muscle, PGC-1α1 enhances the expression of kynurenine aminotransferases (Kats), which convert kynurenine into kynurenic acid. This reduces kynurenine-associated neurotoxicity and generates glutamate as a byproduct. Here, we show that PGC-1α1 elevates aspartate and glutamate levels and increases the expression of glycolysis and malate-aspartate shuttle (MAS) genes. These interconnected processes improve energy utilization and transfer fuel-derived electrons to mitochondrial respiration. This PGC-1α1-dependent mechanism allows trained muscle to use kynurenine metabolism to increase the bioenergetic efficiency of glucose oxidation. Kat inhibition with carbidopa impairs aspartate biosynthesis, mitochondrial respiration, and reduces exercise performance and muscle force in mice. Our findings show that PGC-1α1 activates the MAS in skeletal muscle, supported by kynurenine catabolism, as part of the adaptations to endurance exercise. This crosstalk between kynurenine metabolism and the MAS may have important physiological and clinical implications.
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| 6. |
- Agudelo, Leandro Z., et al.
(författare)
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Metabolic resilience is encoded in genome plasticity
- 2021
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Metabolism plays a central role in evolution, as resource conservation is a selective pressure for fitness and survival.Resource-driven adaptations offer a good model to study evolutionary innovation more broadly. It remains unknown howresource-driven optimization of genome function integrates chromatin architecture with transcriptional phase transitions.Here we show that tuning of genome architecture and heterotypic transcriptional condensates mediate resilience tonutrient limitation. Network genomic integration of phenotypic, structural, and functional relationships reveals that fattissue promotes organismal adaptations through metabolic acceleration chromatin domains and heterotypic PGC1Acondensates. We find evolutionary adaptations in several dimensions; low conservation of amino acid residues withinprotein disorder regions, nonrandom chromatin location of metabolic acceleration domains, condensate-chromatin stabilitythrough cis-regulatory anchoring and encoding of genome plasticity in radial chromatin organization. We show thatenvironmental tuning of these adaptations leads to fasting endurance, through efficient nuclear compartmentalization oflipid metabolic regions, and, locally, human-specific burst kinetics of lipid cycling genes. This process reduces oxidativestress, and fatty-acid mediated cellular acidification, enabling endurance of condensate chromatin conformations.Comparative genomics of genetic and diet perturbations reveal mammalian convergence of phenotype and structuralrelationships, along with loss of transcriptional control by diet-induced obesity. Further, we find that radial transcriptionalorganization is encoded in functional divergence of metabolic disease variant-hubs, heterotypic condensate composition,and protein residues sensing metabolic variation. During fuel restriction, these features license the formation of largeheterotypic condensates that buffer proton excess, and shift viscoelasticity for condensate endurance. This mechanismmaintains physiological pH, reduces pH-resilient inflammatory gene programs, and enables genome plasticity throughtranscriptionally driven cell-specific chromatin contacts. In vivo manipulation of this circuit promotes fasting-likeadaptations with heterotypic nuclear compartments, metabolic and cell-specific homeostasis. In sum, we uncover here ageneral principle by which transcription uses environmental fluctuations for genome function, and demonstrate howresource conservation optimizes transcriptional self-organization through robust feedback integrators, highlighting obesityas an inhibitor of genome plasticity relevant for many diseases.
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| 7. |
- Agudelo, Leandro Z
(författare)
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Skeletal muscle PGC-1α1 and KAT enzymes at the intersection between depression and metabolic disease
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Depression and metabolic diseases are leading causes of disability and major contributors to socioeconomic burden worldwide. Physical activity exerts many beneficial effects that confer direct health improvement in individuals suffering from these disorders. However, the molecular mechanisms underlying the influence of different components of exercise interventions remain unknown. To isolate the impact of skeletal muscle conditioning on stress-induced depression, we used transgenic models that exhibit many of the chronic adaptations to aerobic exercise in skeletal muscle. Here, we show a mechanism by which skeletal muscle PGC-1α1 modulates kynurenine metabolism and mediates resilience to stress-induced depression. PGC-1α1 acts in concert with PPARα/δ transcription factors to induce the expression of kynurenine aminotransferases in skeletal muscle. The activity of this pathway diverts the metabolism of stress-induced kynurenine to kynurenic acid. Since kynurenic acid is unable to cross the blood brain barrier, this peripheral shift protects the brain from stress-induced accumulation of kynurenines. In addition, we further show that skeletal muscle PGC-1α1 and kynurenine aminotransferases are part of the physiological adaptations to aerobic exercise in both rodents and humans. Given that exercise-mediated activation of this pathway leads to peripheral accumulation of kynurenic acid, we evaluated the physiological role of this metabolite in modulating energy homeostasis. Here, we describe that kynurenic acid plays a role in systemic energy homeostasis through the regulation of adipose tissue function and inflammation. Kynurenic acid induces the expression of lipid metabolism, thermogenic and anti-inflammatory gene networks in the white adipose compartment. This reduces body-weight gain and improves glucose tolerance in animals fed a high-fat diet. Mechanistic studies in primary adipocytes show that kynurenic acid activates the G protein-coupled receptor 35. Downstream signaling of this activation is mediated through Ca2+, ERK, CREB and PGC-1α1 stabilization. Finally, activation of GPR35 by kynurenic acid induces the expression of RGS14, which sensitizes β-adrenergic response to specific agonists. In sum, this work uncovers a previously unknown function of PGC-1α1 in skeletal muscle and kynurenic acid in white adipose tissue. Targeting this metabolic node has great potential for the treatment of depression and metabolic diseases such as type-2 diabetes.
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| 8. |
- Agudo, Antonio, et al.
(författare)
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Hemochromatosis (HFE) gene mutations and risk of gastric cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC) study
- 2013
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Ingår i: Carcinogenesis. - : Oxford University Press. - 0143-3334 .- 1460-2180. ; 34:6, s. 1244-1250
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Tidskriftsartikel (refereegranskat)abstract
- Hereditary hemochromatosis (HH) is a strong risk factor for hepatocellular cancer, and mutations in the HFE gene associated with HH and iron overload may be related to other tumors, but no studies have been reported for gastric cancer (GC). A nested case-control study was conducted within the European Prospective Investigation into Cancer and Nutrition (EPIC), including 365 incident gastric adenocarcinoma and 1284 controls matched by center, sex, age and date of blood collection. Genotype analysis was performed for two functional polymorphisms (C282Y/rs1800562 and H63D/rs1799945) and seven tagSNPs of the HFE genomic region. Association with all gastric adenocarcinoma, and according to anatomical localization and histological subtype, was assessed by means of the odds ratio (OR) and 95% confidence interval (CI) estimated by unconditional logistic regression adjusted for the matching variables. We observed a significant association for H63D with OR (per rare allele) of 1.32 (CI = 1.03-1.69). In subgroup analyses, the association was stronger for non-cardia anatomical subsite (OR = 1.60, CI = 1.16-2.21) and intestinal histological subtype (OR = 1.82, CI = 1.27-2.62). Among intestinal cases, two tagSNPs (rs1572982 and rs6918586) also showed a significant association that disappeared after adjustment for H63D. No association with tumors located in the cardia or with diffuse subtype was found for any of the nine SNPs analyzed. Our results suggest that H63D variant in HFE gene seems to be associated with GC risk of the non-cardia region and intestinal type, possibly due to its association with iron overload although a role for other mechanisms cannot be entirely ruled out.
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| 9. |
- Airiskallio, E., et al.
(författare)
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High temperature oxidation of Fe-Al and Fe-Cr-Al alloys : The role of Cr as a chemically active element
- 2010
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Ingår i: Corrosion Science. - : Elsevier BV. - 0010-938X .- 1879-0496. ; 52:10, s. 3394-3404
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Tidskriftsartikel (refereegranskat)abstract
- Good high-temperature corrosion resistance of Fe-Al alloys in oxidizing environments is due to the alpha-Al2O3 film which is formed on the surface provided temperature is above 900 degrees C and the Al-content of the alloy exceeds the critical value. Ab initio calculations combined with experiments on Fe-13Al, Fe-18Al, Fe-23Al and Fe-10Cr-10Al alloys show that the beneficial effect of Cr on the oxidation resistance is significantly related to bulk effects. The comparison of experimental and calculated results indicates a clear correlation between the Fe-Cr chemical potential difference and the formation of the protective oxide scales. (C) 2010 Elsevier Ltd. All rights reserved.
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| 10. |
- Al-Zoubi, Noura, et al.
(författare)
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Elastic properties of 4d transition metal alloys : Values and trends
- 2019
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Ingår i: Computational materials science. - : ELSEVIER SCIENCE BV. - 0927-0256 .- 1879-0801. ; 159, s. 273-280
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Tidskriftsartikel (refereegranskat)abstract
- Using the Exact Muffin-Tin Orbitals method within the Perdew-Burke-Ernzerhof exchange-correlation approximation for solids and solid surfaces (PBEso1), we study the single crystal elastic constants of 4d transition metals (atomic number Z between 39 and 47) and their binary alloys in the body centered cubic (bcc) and face centered cubic (fcc) structures. Alloys between the first neighbors Z(Z + 1) and between the second neighbors Z(Z + 2) are considered. The lattice constants, bulk moduli and elastic constants are found in good agreement with the available experimental and theoretical data. It is shown that the correlation between the relative tetragonal shear elastic constant C-fcc'-2C(bcc)' and the structural energy difference between the fcc and bcc lattices Delta E is superior to the previously considered models. For a given crystal structure, the equiatomic Z(Z + 2) alloys turn out to have similar structural and elastic properties as the pure elements with atomic number (Z + 1). Furthermore, alloys with composition Z(1-x)(Z + 2)(x) possess similar properties as Z(1-2x)(Z + 1)(2x). The present theoretical data on the structural and the elastic properties of 4d transition metal alloys provides consistent input for coarse scale modeling of material properties.
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