126 research outputs found
Metabolically Healthy and Unhealthy Obese Phenotypes among Arabs and South Asians:Prevalence and Relationship with Cardiometabolic Indicators
Obesity is a public health crisis in Kuwait. However, not all obese individuals are metabolically unhealthy (MuHO) given the link between obesity and future cardiovascular events. We assessed the prevalence of the metabolically healthy obese (MHO) phenotype and its relationship with high sensitivity C-reactive protein (hs-CRP), serum alanine aminotransferase (ALT), and insulin resistance (HOMA-IR) in Arab and South Asian ethnic groups in Kuwait. The national cross-sectional survey of diabetes and obesity in Kuwait adults aged 18–60 years were analysed. The harmonised definition of metabolic syndrome was used to classify metabolic health. Multinomial logistic regression analysis was used to model the relationship between the MHO and MuHO phenotypes and hs-CRP, ALT and HOMA-IR levels. Overall, the prevalence of MHO for body mass index (BMI)- and waist circumference (WC)-defined obesity was 30.8% and 56.0%, respectively; it was greater in women (60.4% and 61.8%, respectively) than men (39.6% and 38.2%, respectively). Prevalence rates were also lower for South Asians than for Arabs. The MHO phenotype had hs-CRP values above 3 µg/mL for each age group category. Men compared to women, and South Asians compared to Arabs had a lower relative risk for the MHO group relative to the MuHO group. This study shows there is high prevalence of MHO in Kuwait
Clocking Auger Electrons
Intense X-ray free-electron lasers (XFELs) can rapidly excite matter, leaving
it in inherently unstable states that decay on femtosecond timescales. As the
relaxation occurs primarily via Auger emission, excited state observations are
constrained by Auger decay. In situ measurement of this process is therefore
crucial, yet it has thus far remained elusive at XFELs due to inherent timing
and phase jitter, which can be orders of magnitude larger than the timescale of
Auger decay. Here, we develop a new approach termed self-referenced attosecond
streaking, based upon simultaneous measurements of streaked photo- and Auger
electrons. Our technique enables sub-femtosecond resolution in spite of jitter.
We exploit this method to make the first XFEL time-domain measurement of the
Auger decay lifetime in atomic neon, and, by using a fully quantum-mechanical
description, retrieve a lifetime of fs for the KLL
decay channel. Importantly, our technique can be generalised to permit the
extension of attosecond time-resolved experiments to all current and future FEL
facilities.Comment: Main text: 20 pages, 3 figures. Supplementary information: 17 pages,
6 figure
Clocking Auger electrons
Intense X-ray free-electron lasers (XFELs) can rapidly excite matter, leaving it in inherently unstable states that decay on femtosecond timescales. The relaxation occurs primarily via Auger emission, so excited-state observations are constrained by Auger decay. In situ measurement of this process is therefore crucial, yet it has thus far remained elusive in XFELs owing to inherent timing and phase jitter, which can be orders of magnitude larger than the timescale of Auger decay. Here we develop an approach termed ‘self-referenced attosecond streaking’ that provides subfemtosecond resolution in spite of jitter, enabling time-domain measurement of the delay between photoemission and Auger emission in atomic neon excited by intense, femtosecond pulses from an XFEL. Using a fully quantum-mechanical description that treats the ionization, core-hole formation and Auger emission as a single process, the observed delay yields an Auger decay lifetime of 2.2_−0.3^+0.2 fs for the KLL decay channel
Seafood in Food Security: a call for bridging the terrestrial-aquatic divide
The contribution of seafood to global food security is being increasingly highlighted in policy. However, the extent to which such claims are supported in the current food security literature is unclear. This review assesses the extent to which seafood is represented in the recent food security literature, both individually and from a food systems perspective, in combination with terrestrially-based production systems. The results demonstrate that seafood remains under-researched compared to the role of terrestrial animal and plant production in food security. Furthermore, seafood and terrestrial production remain siloed, with very few papers addressing the combined contribution or relations between terrestrial and aquatic systems. We conclude that far more attention is needed to the specific and relative role of seafood in global food security and call for the integration of seafood in a wider interdisciplinary approach to global food system research
Correlation-Driven Transient Hole Dynamics Resolved in Space and Time in the Isopropanol Molecule
The possibility of suddenly ionized molecules undergoing extremely fast electron hole (or hole) dynamics prior to significant structural change was first recognized more than 20 years ago and termed charge migration. The accurate probing of ultrafast electron hole dynamics requires measurements that have both sufficient temporal resolution and can detect the localization of a specific hole within the molecule. We report an investigation of the dynamics of inner valence hole states in isopropanol where we use an x-ray pump–x-ray probe experiment, with site and state-specific probing of a transient hole state localized near the oxygen atom in the molecule, together with an ab initio theoretical treatment. We record the signature of transient hole dynamics and make the first tentative observation of dynamics driven by frustrated Auger-Meitner transitions. We verify that the effective hole lifetime is consistent with our theoretical prediction. This state-specific measurement paves the way to widespread application for observations of transient hole dynamics localized in space and time in molecules and thus to charge transfer phenomena that are fundamental in chemical and material physics
Seafood in Food Security: A Call for Bridging the Terrestrial-Aquatic Divide
The contribution of seafood to global food security is being increasingly highlighted in policy. However, the extent to which such claims are supported in the current food security literature is unclear. This review assesses the extent to which seafood is represented in the recent food security literature, both individually and from a food systems perspective, in combination with terrestrially-based production systems. The results demonstrate that seafood remains under-researched compared to the role of terrestrial animal and plant production in food security. Furthermore, seafood and terrestrial production remain siloed, with very few papers addressing the combined contribution or relations between terrestrial and aquatic systems. We conclude that far more attention is needed to the specific and relative role of seafood in global food security and call for the integration of seafood in a wider interdisciplinary approach to global food system research
Histone deacetylases suppress cgg repeat-induced neurodegeneration via transcriptional silencing in models of Fragile X Tremor Ataxia Syndrome
Fragile X Tremor Ataxia Syndrome (FXTAS) is a common inherited neurodegenerative disorder caused by expansion of a CGG trinucleotide repeat in the 59UTR of the fragile X syndrome (FXS) gene, FMR1. The expanded CGG repeat is thought to induce toxicity as RNA, and in FXTAS patients mRNA levels for FMR1 are markedly increased. Despite the critical role of FMR1 mRNA in disease pathogenesis, the basis for the increase in FMR1 mRNA expression is unknown. Here we show that overexpressing any of three histone deacetylases (HDACs 3, 6, or 11) suppresses CGG repeat-induced neurodegeneration in a Drosophila model of FXTAS. This suppression results from selective transcriptional repression of the CGG repeat-containing transgene. These findings led us to evaluate the acetylation state of histones at the human FMR1 locus. In patient-derived lymphoblasts and fibroblasts, we determined by chromatin immunoprecipitation that there is increased acetylation of histones at the FMR1 locus in pre-mutation carriers compared to control or FXS derived cell lines. These epigenetic changes correlate with elevated FMR1 mRNA expression in pre-mutation cell lines. Consistent with this finding, histone acetyltransferase (HAT) inhibitors repress FMR1 mRNA expression to control levels in pre-mutation carrier cell lines and extend lifespan in CGG repeat-expressing Drosophila. These findings support a disease model whereby the CGG repeat expansion in FXTAS promotes chromatin remodeling in cis, which in turn increases expression of the toxic FMR1 mRNA. Moreover, these results provide proof of principle that HAT inhibitors or HDAC activators might be used to selectively repress transcription at the FMR1 locus.open293
Long intronic GAA•TTC repeats induce epigenetic changes and reporter gene silencing in a molecular model of Friedreich ataxia
Friedreich ataxia (FRDA) is caused by hyperexpansion of GAA•TTC repeats located in the first intron of the FXN gene, which inhibits transcription leading to the deficiency of frataxin. The FXN gene is an excellent target for therapeutic intervention since (i) 98% of patients carry the same type of mutation, (ii) the mutation is intronic, thus leaving the FXN coding sequence unaffected and (iii) heterozygous GAA•TTC expansion carriers with ∼50% decrease of the frataxin are asymptomatic. The discovery of therapeutic strategies for FRDA is hampered by a lack of appropriate molecular models of the disease. Herein, we present the development of a new cell line as a molecular model of FRDA by inserting 560 GAA•TTC repeats into an intron of a GFP reporter minigene. The GFP_(GAA•TTC)560 minigene recapitulates the molecular hallmarks of the mutated FXN gene, i.e. inhibition of transcription of the reporter gene, decreased levels of the reporter protein and hypoacetylation and hypermethylation of histones in the vicinity of the repeats. Additionally, selected histone deacetylase inhibitors, known to stimulate the FXN gene expression, increase the expression of the GFP_(GAA•TTC)560 reporter. This FRDA model can be adapted to high-throughput analyses in a search for new therapeutics for the disease
Cytochrome P450 in Pharmacogenetics: An Update
cited By 1Interindividual variability in drug disposition is a major cause of lack of efficacy and adverse effects of drug therapies. The majority of hepatically cleared drugs are metabolized by cytochrome P450 (CYP) enzymes, mainly in families CYP1, CYP2, and CYP3. Genes encoding these enzymes are highly variable with allele distribution showing considerable differences between populations. Genetic variability of especially CYP2C9, CYP2C19, CYP2D6, and CYP3A5 is known to have clear clinical impact on drugs that are metabolized by these enzymes. CYP1A2, CYP2A6, CYP2B6, CYP2C8, and CYP3A4 all show variability that affects pharmacokinetics of drugs as well, but so far the evidence regarding their clinical implications is not as conclusive. In this review, we provide an up-to-date summary of the pharmacogenetics of the major human drug-metabolizing CYP enzymes, focusing on clinically significant examples. © 2018 Elsevier Inc.Peer reviewe
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