229 research outputs found

    Relationship of hyperglycaemia, hypoglycaemia, and glucose variability to atherosclerotic disease in type 2 diabetes

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    Objective: Type 2 diabetes mellitus (T2DM) is known to be associated with increased cardiovascular risk. The aim of this study was therefore to investigate the independent effects of hyperglycaemia, hypoglycaemia, and glucose variability on microvascular and macrovascular disease in T2DM. Methods. Subjects with T2DM of 7.8mmol/L (β=15.83, p=0005) was the sole independent predictor of albuminuria in generalised linear regression. Conclusions. This study demonstrates that hypoglycaemia is associated with the occurrence of atherosclerotic disease while hyperglycaemia is associated with microvascular disease in a Caucasian population with T2DM of recent duration.peer-reviewe

    Forward and Inverse Modeling of the Emission and Transmission Spectrum of GJ 436b: Investigating Metal Enrichment, Tidal Heating, and Clouds

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    The Neptune-mass GJ 436b is one of the most-studied transiting exoplanets with repeated measurements of both its thermal emission and transmission spectra. We build on previous studies to answer outstanding questions about this planet, including its potentially high metallicity and tidal heating of its interior. We present new observations of GJ 436b's thermal emission at 3.6 and 4.5 micron, which reduce uncertainties in estimates of GJ 436b's flux at those wavelengths and demonstrate consistency between Spitzer observations spanning more than 7 years. We analyze the Spitzer thermal emission photometry and Hubble WFC3 transmission spectrum in tandem. We use a powerful dual-pronged modeling approach, comparing these data to both self-consistent and retrieval models. We vary the metallicity, intrinsic luminosity from tidal heating, disequilibrium chemistry, and heat redistribution. We also study the effect of clouds and photochemical hazes on the spectra, but do not find strong evidence for either. The self-consistent and retrieval modeling combine to suggest that GJ 436b has a high atmospheric metallicity, with best fits at or above several hundred times solar metallicity, tidal heating warming its interior with best-fit intrinsic effective effective temperatures around 300--350 K, and disequilibrium chemistry. High metal-enrichments (>600x solar) can only occur from the accretion of rocky, rather than icy, material. Assuming Tint~300--350 K, we find that Q'~2x10^5--10^6, larger than Neptune's Q', and implying a long tidal circularization timescale for the planet's orbit. We suggest that Neptune-mass planets may be a more diverse class than previously imagined, with metal-enhancements potentially spanning several orders of magnitude, to perhaps over 1000x solar metallicity. High fidelity observations with instruments like JWST will be critical for characterizing this diversity.Comment: 15 pages, 18 figures. Revised for publication in Ap

    Are there functional consequences of a reduction in selenium intake in UK subjects?

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    Dietary Se levels in the UK have fallen over the last 20 years and recent surveys indicate that average Se intakes are 30-40 microg/d, which is well below the current UK reference nutrient intake for adult men (75 microg/d) or women (60 microg/d). Functional consequences of this decline have not been recognised, although epidemiological data suggest it may contribute to increased risk of infections and incidence of some cancers. Previous data have indicated that biochemical changes in Se-dependent proteins occur in otherwise healthy UK subjects given small Se supplements. The current studies have focused on the effect of small Se supplements on the immune response since there is evidence of specific interactions between Se intake and viral replication, and since the potential anti-cancer effects of Se may be mediated by non-antioxidant effects of Se such as changes in immune function. Data indicate that subjects given small Se supplements (50 or 100 microg Se/d) have changes in the activity of Se-dependent enzymes and evidence of improved immune function and clearance of an administered live attenuated virus in the form of poliovirus vaccine. Responses of individual subjects to Se supplements are variable, and current work is evaluating potential explanations for this variability, including genetic variability and pre-existing Se status

    Solarflux

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    Solarflux is a technological company developing solar concentrators to provide clean thermal energy. The issue that Solarflux is facing is the high installation cost of trenching in order to connect their concentrator to the grid for power. Therefore, Solarflux is looking into design alternatives to provide off-grid power to their product. Our capstone team is collaborating with Solarflux to help address this issue by designing a system to provide their solar concentrators with off-grid power. The goal of our final design is to provide Solarflux with 115 VAC of renewable, off-grid power via a photovoltaic (PV) solar powered system that will be attached to their flagship product. Our system will be powering the concentrator\u27s motor for sun tracking, and control system for operations. This means that we must be able to have enough solar power during the day to operate the system at peak power, as well as enough stored power to maintain system operations during the night, as well as any minimal sunlight event. The scope of our project is to design a solar powered system able to operate at a peak power of 200W, to supply enough battery storage for 2 to 3 days worth of stored power while maintaining healthy battery life, to develop a means of attaching our system onto the existing concentrator\u27s design, and to provide our client with electrical schematics and wind loading analysis to demonstrate the practicality of our design. Our proposed solar powered system consists of 10 solar panels collecting our DC power, a charge controller to regulate the voltages being outputted from the panels, 4 batteries to provide 14.4 kWh of storage, an inverter that will convert our power to 115 VAC to feed into the concentrator, and fuses where necessary to avoid dangers of electrical overload. This system has a minimum 10 year life expectancy with light maintenance required, and easy manufacturability as one cohesive product for our client

    The Adaptive Cycle As a Lens for Service Learning – Community Engagement Partnerships

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    This paper deploys the adaptive cycle as a construct to understand the dynamics of community engagement and partnership building during an international service-learning project. A multi-disciplinary team of USA-based university students collaborated with a local community in Zambia to build two ventilated improved pit (VIP) latrines. Post-field project reflection challenged the ‘product-first’ view commonly held in service learning projects.  Time was a central point of post-field reflection. Through critical scrutiny, the team came to recognize that contextually sensitive relationship building had been essential in enabling community ownership of the project.  The construct of the adaptive cycle provided a crucial analytical tool for tracing the process through which partners from very different backgrounds achieved a sense of common purpose and opened the way for an understanding of community engagement as weaving a thread through the complex dynamics of partnership. The adaptive cycle may be useful in the preparation and implementation framework for other service learning projects emanating from institutions of higher education

    Expression pattern of glycoside hydrolase genes in Lutzomyia longipalpis reveals key enzymes involved in larval digestion

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    The sand fly Lutzomyia longipalpis is the most important vector of American Visceral Leishmaniasis. Adults are phytophagous (males and females) or blood feeders (females only), and larvae feed on solid detritus. Digestion in sand fly larvae has scarcely been studied, but some glycosidase activities putatively involved in microorganism digestion were already described. Nevertheless, the molecular nature of these enzymes, as the corresponding genes and transcripts, were not explored yet. Catabolism of microbial carbohydrates in insects generally involves β-1,3-glucanases, chitinases, and digestive lysozymes. In this work, the transcripts of digestive β-1,3-glucanase and chitinases were identified in the L. longipalpis larvae throughout analysis of sequences and expression patterns of glycoside hydrolases families 16, 18, and 22. The activity of one i-type lysozyme was also registered. Interestingly, this lysozyme seems to play a role in immunity, rather than digestion. This is the first attempt to identify the molecular nature of sand fly larval digestive enzymes

    Selection on dispersal drives evolution of metabolic capacities for energy production in female wing-polymorphic sand field crickets, Gryllus firmus

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    Life history and metabolism covary, but the mechanisms and individual traits responsible for these linkages remain unresolved. Dispersal capability is a critical component of life histories that is constrained by metabolic capacities for energy production. Conflicting relationships between metabolism and life histories may be explained by accounting for variation in dispersal and maximal metabolic rates. We used female wing-polymorphic sand field crickets, Gryllus firmus, selected either for long wings (LW) and flight-capability or short wings (SW) and high early lifetime fecundity to test the hypothesis that selection on dispersal capability drives the evolution of metabolic capacities. While resting metabolic rates were similar, long-winged crickets reached higher maximal metabolic rates than short-winged crickets, resulting in improved running performance. We further provided insight into the mechanisms responsible for covariation between life history and metabolism by comparing mitochondrial content of tissues involved in powering locomotion and assessing function of mitochondria isolated from long- and short-winged crickets. This demonstrated that larger metabolic capacities in long-winged crickets were underpinned by increases in mitochondrial content of dorsoventral flight muscle and enhanced bioenergetic capacities of mitochondria within the fat body, a tissue responsible for fuel storage and mobilization. Thus, selection on flight-capability remodels metabolism in a trait and tissue-specific manner to enlarge metabolic capacities necessary for dispersal

    Development of Leishmania mexicana in Lutzomyia longipalpis in the absence of sugar feeding

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    The leishmaniases are caused by Leishmania parasites and transmitted through the bites of phlebotomine sand flies. During parasite development inside the vector's midgut, promastigotes move towards the stomodeal valve, a mechanism that is crucial for transmission. It has been reported that the sugar meal acquired by sand flies during feeding between bloodmeals is essential for the development and migration of parasites. We demonstrated that the distribution of Leishmania mexicana parasites was affected by the sugar meals obtained by the sand flies. Promastigote migration towards the cardia region seems to be only partially based on the stimuli provided by sugar molecules. In the absence of sugars, significant amounts of parasites developed in the hindgut. In addition, sugar meals were important for the survival of sand flies, especially during blood digestion, presumably supporting their energy requirements

    The use of film-based interventions in adolescent mental health education: A systematic review

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    Film-based interventions have been embraced by adolescents as educational tools, but their efficacy in mental health education remains under-explored. In this review, we systematically examined the use of film-based interventions in adolescent mental health education. A systematic review of the empirical literature was conducted using the following databases: Academic Search Complete, Education Full Text [H.W. Wilson], CINAHL Plus with Full Text, Humanities Full Text [H.W. Wilson], MEDLINE, APA PsycArticles, APA PsycInfo, Psychology and Behavioral Sciences Collection, Social Sciences Full Text [H.W. Wilson], Soc Index, ERIC. Risk of Bias were assessed using Version 2 of the Cochrane RoB tool for randomised trials (RoB2) or the Cochrane Collaboration Risk of Bias In Non-randomised Studies of Interventions (ROBINS-I). Ten peer-reviewed studies were included in this review. Film emerged as a promising education method for enhancing metal health literacy and reducing stigma. Mixed reports were found for improving attitudes towards help-seeking, with narrative-based films having a weaker effect on attitudes towards help-seeking when compared with more instructive approaches. No study focussed on resilience. This review highlights the utility and potential for film-based interventions in adolescent mental health education. Further research is warranted around how best to implement such interventions to engage adolescents

    Forward and Inverse Modeling of the Emission and Transmission Spectrum of GJ 436b: Investigating Metal Enrichment, Tidal Heating, and Clouds

    Get PDF
    The Neptune-mass GJ 436b is one of the most studied transiting exoplanets with repeated measurements of its thermal emission and transmission spectra. We build on previous studies to answer outstanding questions about this planet, including its potentially high metallicity and tidal heating of its interior. We present new observations of GJ 436b's thermal emission at 3.6 and 4.5 μm, which reduce uncertainties in estimates of GJ 436b's flux at those wavelengths and demonstrate consistency between Spitzer observations spanning more than 7 yr. We analyze the Spitzer thermal emission photometry and Hubble WFC3 transmission spectrum. We use a dual-pronged modeling approach of both self-consistent and retrieval models. We vary the metallicity, intrinsic luminosity from tidal heating, disequilibrium chemistry, and heat redistribution. We also study clouds and photochemical hazes, but do not find strong evidence for either. The self-consistent and retrieval models combine to suggest that GJ 436b has a high atmospheric metallicity, with best fits at or above several hundred times solar metallicity, tidal heating warming its interior with best-fit intrinsic effective temperatures around 300–350 K, and disequilibrium chemistry. High metal enrichments (>600× solar) occur from the accretion of rocky, rather than icy, material. Assuming the interior temperature T int ~ 300–350 K, we find a dissipation factor Q' ~ 2 × 10^5–10^6, larger than Neptune's Q', implying a long tidal circularization timescale for the orbit. We suggest that Neptune-mass planets may be more diverse than imagined, with metal enhancements spanning several orders of magnitude, to perhaps over 1000× solar metallicity. High-fidelity observations with instruments like the James Webb Space Telescope will be critical for characterizing this diversity
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