185 research outputs found

    Contributions of amino acid, acylcarnitine and sphingolipid profiles to type 2 diabetes risk among South-Asian Surinamese and Dutch adults

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    Introduction: People of South Asian origin are at high risk of type 2 diabetes (T2D), but the underpinning mechanisms are not fully understood. We determined ethnic differences in acylcarnitine, amino acid and sphingolipid concentrations and determined the associations with T2D. Research design and methods: Associations between these metabolites and incident T2D among Dutch and South-Asian Surinamese were determined in participants from the Healthy Life in an Urban Setting (HELIUS) study (Amsterdam, the Netherlands) using Prentice-weighted Cox regression. The HELIUS study includes 95 incident T2D cases and a representative subcohort of 700 people from a cohort of 5977 participants with a mean follow-up of 4 years. Results: Concentrations of acylcarnitines were comparable between both ethnic groups. Amino acid and lactosylceramide concentrations were higher among South-Asian Surinamese than Dutch (eg, isoleucine 65.7 (SD 16.3) vs 60.7 (SD 15.6) µmol/L). Ceramide concentrations were lower among South-Asian Surinamese than Dutch (eg, Cer d18:1 8.48 (SD 2.04) vs 9.08 (SD 2.29) µmol/L). Metabolic dysregulation preceded T2D without evidence for a multiplicative interaction by ethnicity. Most amino acids and (dihydro)ceramides were associated with increased risk (eg, Cer d18:1 HR 2.38, 95% CI 1.81 to 3.12) while acylcarnitines, glycine, glutamine and lactosylceramides were associated with decreased risk for T2D (eg, LacCer d18:2 HR 0.56, 95% CI 0.42 to 0.77). Conclusions: Overall, these data suggest that the disturbances underlying amino acid and sphingolipid metabolism may be predictive of T2D risk in populations of both South Asian and European background. These observations may be used as starting point to unravel the underlying metabolic disturbances

    A hydrothermal karst-hosted U-P deposit related to Pangea break-up: Itataia deposit, Borborema Province, Northeastern Brazil - a review

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    The Itataia U-P deposit holds the second largest uranium reserve in Brazil. All of the uranium is contained within the microcrystalline structure of fluorapatite, which is the ore mineral of the collophanite bodies. The main lithology that hosts the mineralization is marble, and the collophanite occurs as massive bodies, stockwork vein, breccia, filling vugs in episyenites, and disseminated in host rocks. This review shows that five important episodes in the Northern Borborema Province, leading to the consolidation of the Itataia U-P deposit: i) deposition of a phosphate-rich Neoproterozoic supracrustal quartz-pelite-carbonate sequence, represented by the Itataia Group; ii) building of the Neoproterozoic Tamboril-Santa Quitéria continental magmatic arc, responsible for the partial melting of the phosphate-rich supracrustal sequence; iii) Na-metasomatism related to Neoproterozoic/Cambrian-Ordovician post-collisional to anorogenic granitoids, which generated uranium-rich albitite, as well as barren episyenite bodies; iv) Cretaceous hydrothermal karstic event related to the generalized fracturing of the continental crust caused by the Pangea break-up and making possible the deposition of collophanites in the karstic features and vugs in episyenites; v) reworking of the collophanites with the deposition of breccia in paleokarstic features in the marble

    TITAN's Digital RFQ Ion Beam Cooler and Buncher, Operation and Performance

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    We present a description of the Radio Frequency Quadrupole (RFQ) ion trap built as part of the TITAN facility. It consists of a gas-filled, segmented, linear Paul trap and is the first stage of the TITAN setup with the purpose of cooling and bunching radioactive ion beams delivered from ISAC-TRIUMF. This is the first such device to be driven digitally, i.e., using a high voltage (Vpp=400VV_{pp} = \rm{400 \, V}), wide bandwidth (0.2<f<1.2MHz0.2 < f < 1.2 \, \rm{MHz}) square-wave as compared to the typical sinusoidal wave form. Results from the commissioning of the device as well as systematic studies with stable and radioactive ions are presented including efficiency measurements with stable 133^{133}Cs and radioactive 124,126^{124, 126}Cs. A novel and unique mode of operation of this device is also demonstrated where the cooled ion bunches are extracted in reverse mode, i.e., in the same direction as previously injected.Comment: 34 pages, 17 figure

    Method to compute the stress-energy tensor for the massless spin 1/2 field in a general static spherically symmetric spacetime

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    A method for computing the stress-energy tensor for the quantized, massless, spin 1/2 field in a general static spherically symmetric spacetime is presented. The field can be in a zero temperature state or a non-zero temperature thermal state. An expression for the full renormalized stress-energy tensor is derived. It consists of a sum of two tensors both of which are conserved. One tensor is written in terms of the modes of the quantized field and has zero trace. In most cases it must be computed numerically. The other tensor does not explicitly depend on the modes and has a trace equal to the trace anomaly. It can be used as an analytic approximation for the stress-energy tensor and is equivalent to other approximations that have been made for the stress-energy tensor of the massless spin 1/2 field in static spherically symmetric spacetimes.Comment: 34 pages, no figure

    Aging selectively dampens oscillation of lipid abundance in white and brown adipose tissue

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    Lipid metabolism is under the control of the circadian system and circadian dysregulation has been linked to obesity and dyslipidemia. These factors and outcomes have also been associated to, or affected by, the process of aging. Here, we investigated whether murine white (WAT) and brown (BAT) adipose tissue lipids exhibit rhythmicity and if this is affected by aging. To this end, we have measured the 24 h lipid profiles of WAT and BAT using a global lipidomics analysis of >1100 lipids. We observed rhythmicity in nearly all lipid classes including glycerolipids, glycerophospholipids, sterol lipids and sphingolipids. Overall, similar to 22% of the analyzed lipids were considered rhythmic in WAT and BAT. Despite a general accumulation of lipids upon aging the fraction of oscillating lipids decreased in both tissues to 14% and 18%, respectively. Diurnal profiles of lipids in BAT appeared to depend on the lipid acyl chain length and this specific regulation was lost in aged mice. Our study revealed how aging affects the rhythmicity of lipid metabolism and could contribute to the quest for targets that improve diurnal lipid homeostasis to maintain cardiometabolic health during aging.Diabetes mellitus: pathophysiological changes and therap
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