90 research outputs found

    Methodological advancements in organ-specific ectopic lipid quantitative characterization: Effects of high fat diet on muscle and liver intracellular lipids.

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    Ectopic lipid accumulation is a hallmark of metabolic diseases, linking obesity to non-alcoholic fatty liver disease, insulin resistance and diabetes. The use of zebrafish as a model of obesity and diabetes is raising due to the conserved properties of fat metabolism between humans and zebrafish, the homologous genes regulating lipid uptake and transport, the implementation of the '3R's principle and their cost-effectiveness. To date, a method allowing the conservation of lipid droplets (LDs) and organs in zebrafish larvae to image ectopic lipids is not available. Our objectives were to develop a novel methodology to quantitatively evaluate organ-specific LDs, in skeletal muscle and liver, in response to a nutritional perturbation. We developed a novel embedding and cryosectioning protocol allowing the conservation of LDs and organs in zebrafish larvae. To establish the quantitative measures, we used a three-arm parallel nutritional intervention design. Zebrafish larvae were fed a control diet containing 14% of nutritional fat or two high fat diets (HFDs) containing 25 and 36% of dietary fats. In muscle and liver, LDs were characterized using immunofluorescence confocal microscopy. In liver, intrahepatocellular lipids were discriminated from intrasinusoid lipids. To complete liver characteristics, fibrosis was identified with Masson's Trichrome staining. Finally, to confirm the conservation and effect of HFD, molecular players of fat metabolism were evaluated by RT-qPCR. The cryosections obtained after setting up the embedding and cryopreservation method were of high quality, preserving tissue morphology and allowing the visualization of ectopic lipids. Both HFDs were obesogenic, without modifying larvae survival or development. Neutral lipid content increased with time and augmented dietary fat. Intramuscular LD volume density increased and was explained by an increase in LDs size but not in numbers. Intrahepatocellular LD volume density increased and was explained by an increased number of LDs, not by their increased size. Sinusoid area and lipid content were both increased. Hepatic fibrosis appeared with both HFDs. We observed alterations in the expression of genes associated with LD coating proteins, LD dynamics, lipogenesis, lipolysis and fatty acid oxidation. In this study, we propose a reproducible and fast method to image zebrafish larvae without losing LD quality and organ morphology. We demonstrate the impact of HFD on LD characteristics in liver and skeletal muscle accompanied by alterations of key players of fat metabolism. Our observations confirm the evolutionarily conserved mechanisms in lipid metabolism and reveal organ specific adaptations. The methodological advancements proposed in this work open the doors to study organelle adaptations in obesity and diabetes related research such as lipotoxicity, organelle contacts and specific lipid depositions

    Unequal bequests

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    Using data from the Health and Retirement Study (HRS), we make two contributions to the literature on end-of-life transfers. First, we show that unequal bequests are much more prevalent than generally recognized, with more than one-third of parents with wills planning to divide their estates unequally among their children. Plans for unequal division are particularly concentrated in “weak relationships”, i.e., families with stepchildren and families with genetic children with whom parents have limited or no contact. Second, we find that many older Americans have no wills. Although the probability of having a will increases with age, 30 percent of individuals aged 70 plus are without a will and, of the HRS respondents who died between 1995 and 2012, nearly 40 percent died intestate

    XPS characterization of (copper-based) coloured stains formed on limestone surfaces of outdoor Roman monuments

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    Limestone basements holding bronzes or other copper alloys artefacts such as sculptures, decorations and dedicatory inscriptions are frequently met both in modern and ancient monuments. In outdoor conditions, such a combination implies the corrosion products of the copper based alloy, directly exposed to rainwater, will be drained off and migrate through the porous surfaces, forming stains of different colours and intensities, finally causing the limestone structures to deteriorate

    Overview of ASDEX Upgrade results

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    Recent results from the ASDEX Upgrade experimental campaigns 2001 and 2002 are presented. An improved understanding of energy and particle transport emerges in terms of a 'critical gradient' model for the temperature gradients. Coupling this to particle diffusion explains most of the observed behaviour of the density profiles, in particular, the finding that strong central heating reduces the tendency for density profile peaking. Internal transport barriers (ITBs) with electron and ion temperatures in excess of 20 keV (but not simultaneously) have been achieved. By shaping the plasma, a regime with small type II edge localized modes (ELMs) has been established. Here, the maximum power deposited on the target plates was greatly reduced at constant average power. Also, an increase of the ELM frequency by injection of shallow pellets was demonstrated. ELM free operation is possible in the quiescent H-mode regime previously found in DIII-D which has also been established on ASDEX Upgrade. Regarding stability, a regime with benign neoclassical tearing modes (NTMs) was found. During electron cyclotron current drive (ECCD) stabilization of NTMs, βN could be increased well above the usual onset level without a reappearance of the NTM. Electron cyclotron resonance heating and ECCD have also been used to control the sawtooth repetition frequency at a moderate fraction of the total heating power. The inner wall of the ASDEX Upgrade vessel has increasingly been covered with tungsten without causing detrimental effects on the plasma performance. Regarding scenario integration, a scenario with a large fraction of noninductively driven current (≥50%), but without ITB has been established. It combines improved confinement (τE/τITER98 ≈ 1.2) and stability (βN ≤ 3.5) at high Greenwald fraction (ne/nGW ≈ 0.85) in steady state and with type II ELMy edge and would offer the possibility for long pulses with high fusion power at reduced current in ITER

    Where Are the Returns to Lifelong Learning?

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    We investigate the labour market determinants and outcomes of adult participation in formal education (lifelong learning) in Australia, a country with high levels of adult education. Employing longitudinal data and fixed effects methods allows identification of effects on outcomes free of ability bias. Different trends in outcomes across groups are also allowed for. The impacts of adult education differ by gender and level of study, with small or zero labour market returns in many cases. Wage rates only increase for males undertaking university studies. For men, vocational education and training (VET) lead to higher job satisfaction and fewer weekly hours. For women, VET is linked to higher levels of satisfaction with employment opportunities and higher employment probabilities

    Where are the returns to lifelong learning?

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    Participation in formal education during adulthood (ages 25 to 54) is a key part of lifelong learning. Employing unique longitudinal data for Australia, we highlight the prevalence of such study, the varied reasons for undertaking it (consumption, career development, job and home disruption), and investigate whether it is socially valuable. Our more detailed estimates of the labour market return to adult education (wage rates, employment, hours of work and occupational status) confirm previous studies that generally found such returns to be small and isolated. We contribute to this literature by also estimating the effect of adult education on job satisfaction and satisfaction with employment opportunities. Increases in satisfaction help rationalise the education enrolment decisions of these adults

    Spatially resolved measurement of photon fluxes from the JET divertor on the visible range

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