1,603 research outputs found

    Some abnormalities of platelet and leucocyte function, and changes in free radical activity: their possible roles in the development of diabetic microvascular complications

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    Microangiopathy is a major cause of morbidity and mortality in diabetes mellitus, and its pathogenesis remains poorly understood. Abnormalities of both in vivo and in vitro haemostasis have been extensively reported, particularly changes in platelet function have been described in cross-sectional studies, and cause-endeffect relationships have been postulated. It is also suggested that neutrophil accumulation at sites of inflammation, including vascular endothelium, can induce tissue damage. Three classes of mediators are particularly likely to participate in the pathogenesis of neutrophil-mediated vascular injury : granule enzymes, reactive oxygen metabolites, and products of membrane phospholipids.The aims of this thesis were to investigate changes in platelet function in insulindependent diabetic patients in relation to glycaemic control, and microvascular disease in the form of retinopathy. In addition, the changes in platelet function in non-insulin-dependent diabetic patients at diagnosis, and the effect of glycaemic control and oral hypoglycaemic therapy were assessed. As a measure of neutrophil activity, neutrophil elastase was measured in insulin-dependent diabetic patients with retinopathy. The changes in elastase levels in response to acute insulin- induced hypoglycaemia in non-diabetic subjects were also evaluated. A further aim was to measure a marker for free radical activity in insulin-dependent diabetes.The changes in platelet density, thromboxane production and receptor sensitivity demonstrated are consistent with platelets from diabetic patients being hyperaggregable and contributing towards microvascular disease. The increase in neutrophil elastase levels in insulin-dependent diabetic patients, and the rise in normals in response to hypoglycaemia are consistent with leucocyte-endothelial interaction contributing towards diabetic vascular disease. Although, the marker for free radical activity was not increased in the retinopathic insulin-dependent diabetic patients studied, it is probable that abnormalities of lipid metabolism related to free radical activity may still contribute to diabetic vascular disease.Although good glycaemic control can delay the onset and slow the progress of diabetic complications, specific therapeutic agents that interfere with haemostasis, leucocyte function and free radical activity may also have a protective role in the development of diabetic complications. In addition, use of these agents may also give greater understanding of the aetiopathogenesis of diabetic microangiopathy

    Nicotine treatment decreases food intake and body weight via a leptin-independent pathway in Psammomys obesus

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    It has been reported previously that leptin may be involved in nicotine\u27s ability to reduce body weight. Our aim was to investigate whether the anorexic action of nicotine is related to the actions of leptin by utilizing lean leptin-sensitive and obese leptin-resistant Psammomys obesus. Lean and obese P. obesus were assigned to receive nicotine sulphate at 6, 9 or 12 mg/day or saline (control) for 9 days (n = 6-10 in each group), administered using mini-osmotic pumps. Food intake, body weight, plasma leptin concentrations, plasma insulin and blood glucose were measured at baseline and throughout the study period. Nicotine treatment reduced food intake by up to 40% in lean and obese P. obesus. Plasma leptin levels fell significantly only in lean nicotine-treated animals, whereas no changes were observed in obese nicotine-treated animals. However, both lean and obese nicotine-treated animals had similar reductions in body weight. Our results show that nicotine has dramatic effects on food intake and body weight, however, these changes appear to be independent of the leptin signalling pathway.<br /

    Reduced-Complexity Maximum-Likelihood Detection in Downlink SDMA Systems

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    The literature of up-link SDMA systems is rich, but at the time of writing there is a paucity of information on the employment of SDMA techniques in the down-link. Hence, in this paper a Space Division Multiple Access (SDMA) down-link (DL) multi-user communication system invoking a novel low-complexity Maximum Likelihood (ML) space-time detection technique is proposed, which can be regarded as an advanced extension of the Complex Sphere Decoder (CSD). We demonstrate that as opposed to the previously published variants of the CSD, the proposed technique may be employed for obtaining a high effective throughput in the so-called “over-loaded” scenario, where the number of transmit antennas exceeds that of the receive antennas. The proposed method achieves the optimum performance of the ML detector even in heavily over-loaded scenarios, while the associated computational complexity is only moderately increased. As an illustrative example, the required Eb/N0 increased from 2 dB to 9 dB, when increasing the normalized system load from unity, representing the fully loaded system, to a normalized load of 1.556

    Decarbonisation, Decentralisation, Democratisation & Digitalisation - Fighting fire with innovation

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    Addressing global warming requires innovative engineering solutions. The four megatrends: Decarbonisation, Decentralisation, Democratisation, and Digitalisation (the 4Ds) are crucial. Decentralisation emphasises localised energy resources, with Digitalisation ensuring automated grid management in response to variable renewable energies. Hitachi Energy’s TXpert Ecosystem provides advanced transformer monitoring for grid reliability. In this technological age, merging domain knowledge with digital solutions is vital for sustainable energy management

    Measurement of the Nodal Precession of WASP-33 b via Doppler Tomography

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    We have analyzed new and archival time series spectra taken six years apart during transits of the hot Jupiter WASP-33 b, and spectroscopically resolved the line profile perturbation caused by the Rossiter-McLaughlin effect. The motion of this line profile perturbation is determined by the path of the planet across the stellar disk, which we show to have changed between the two epochs due to nodal precession of the planetary orbit. We measured rates of change of the impact parameter and the sky-projected spin-orbit misalignment of db/dt=0.02280.0018+0.0050db/dt=-0.0228_{-0.0018}^{+0.0050} yr1^{-1} and dλ/dt=0.4870.076+0.089d\lambda/dt=-0.487_{-0.076}^{+0.089}~^{\circ} yr1^{-1}, respectively, corresponding to a rate of nodal precession of dΩ/dt=0.3730.083+0.031d\Omega/dt=0.373_{-0.083}^{+0.031}~^{\circ} yr1^{-1}. This is only the second measurement of nodal precession for a confirmed exoplanet transiting a single star. Finally, we used the rate of precession to set limits on the stellar gravitational quadrupole moment of 9.4×105<J2<6.1×1049.4\times10^{-5}<J_2<6.1\times10^{-4}.Comment: Published in ApJL. 5 pages, 3 figures. Corrected error in the calculation of J_

    Representing moisture fluxes and phase changes in glacier debris cover using a reservoir approach

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    Due to the complexity of treating moisture in supraglacial debris, surface energy balance models to date have neglected moisture infiltration and phase changes in the debris layer. The latent heat flux (QL) is also often excluded due to the uncertainty in determining the surface vapour pressure. To quantify the importance of moisture on the surface energy and climatic mass balance (CMB) of debris-covered glaciers, we developed a simple reservoir parameterization for the debris ice and water content, as well as an estimation of the latent heat flux. The parameterization was incorporated into a CMB model adapted for debris-covered glaciers. We present the results of two point simulations, using both our new “moist” and the conventional “dry” approaches, on the Miage Glacier, Italy, during summer 2008 and fall 2011. The former year coincides with available in situ glaciological and meteorological measurements, including the first eddy-covariance measurements of the turbulent fluxes over supraglacial debris, while the latter contains two refreeze events that permit evaluation of the influence of phase changes. The simulations demonstrate a clear influence of moisture on the glacier energy and mass-balance dynamics. When water and ice are considered, heat transmission to the underlying glacier ice is lower, as the effective thermal diffusivity of the saturated debris layers is reduced by increases in both the density and the specific heat capacity of the layers. In combination with surface heat extraction by QL, subdebris ice melt is reduced by 3.1% in 2008 and by 7.0% in 2011 when moisture effects are included. However, the influence of the parameterization on the total accumulated mass balance varies seasonally. In summer 2008, mass loss due to surface vapour fluxes more than compensates for the reduction in ice melt, such that the total ablation increases by 4.0 %. Conversely, in fall 2011, the modulation of basal debris temperature by debris ice results in a decrease in total ablation of 2.1 %. Although the parameterization is a simplified representation of the moist physics of glacier debris, it is a novel attempt at including moisture in a numerical model of debris-covered glaciers and one that opens up additional avenues for future research

    Phenology of the Diamondback moth (Plutella xylostella) in the UK and provision of decision support for brassica growers

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    In the UK, severe infestations by Plutella xylostella occur sporadically and are due mainly to the immigration of moths. The aim of this study was to develop a more detailed understanding of the phenology of P. xylostella in the UK and investigate methods of monitoring moth activity, with the aim of providing warnings to growers. Plutella xylostella was monitored using pheromone traps, by counting immature stages on plants, and by accessing citizen science data (records of sightings of moths) from websites and Twitter. The likely origin of migrant moths was investigated by analysing historical weather data. The study confirmed that P. xylostella is a sporadic but important pest, and that very large numbers of moths can arrive suddenly, most often in early summer. Their immediate sources are countries in the western part of continental Europe. A network of pheromone traps, each containing a small camera sending images to a website, to monitor P. xylostella remotely provided accessible and timely information, but the particular system tested did not appear to catch many moths. In another approach, sightings by citizen scientists were summarised on a web page. These were accessed regularly by growers and, at present, this approach appears to be the most effective way of providing timely warnings

    Are glucose profiles well-controlled within the targets recommended by the International Diabetes Federation in type 2 diabetes? A meta-analysis of results from continuous glucose monitoring based studies

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    AIMS: To assess continuous glucose monitoring (CGM) derived intra-day glucose profiles using global guideline for type 2 diabetes recommended by the International Diabetes Federation (IDF). METHODS: The Cochrane Library, MEDLINE, PubMed, CINAHL and Science Direct were searched to identify observational studies reporting intra-day glucose profiles using CGM in people with type 2 diabetes on any anti-diabetes agents. Overall and subgroup analyses were conducted to summarise mean differences between reported glucose profiles (fasting glucose, pre-meal glucose, postprandial glucose and post-meal glucose spike/excursion) and the IDF targets. RESULTS: Twelve observational studies totalling 731 people were included. Pooled fasting glucose (0.81 mmol/L, 95% CI, 0.53-1.09 mmol/L), postprandial glucose after breakfast (1.63 mmol/L, 95% CI, 0.79-2.48 mmol/L) and post-breakfast glucose spike (1.05 mmol/L, 95% CI, 0.13-1.96 mmol/L) were significantly higher than the IDF targets. Pre-lunch glucose, pre-dinner glucose and postprandial glucose after lunch and dinner were above the IDF targets but not significantly. Subgroup analysis showed significantly higher fasting glucose and postprandial glucose after breakfast in all groups: HbA1c <7% and ≥7% (53 mmol/mol) and duration of diabetes <10 years and ≥10 years. CONCLUSIONS: Independent of HbA1c, fasting glucose and postprandial glucose after breakfast are not well-controlled in type 2 diabetes

    miR-34a-/- mice are susceptible to diet-induced obesity

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    Objective: MicroRNA (miR)−34a regulates inflammatory pathways, and increased transcripts have been observed in serum and subcutaneous adipose of subjects who have obesity and type 2 diabetes. Therefore, the role of miR-34a in adipose tissue inflammation and lipid metabolism in murine diet-induced obesity was investigated. Methods: Wild-type (WT) and miR-34a−/− mice were fed chow or high-fat diet (HFD) for 24 weeks. WT and miR-34a−/− bone marrow-derived macrophages were cultured in vitro with macrophage colony-stimulating factor (M-CSF). Brown and white preadipocytes were cultured from the stromal vascular fraction (SVF) of intrascapular brown and epididymal white adipose tissue (eWAT), with rosiglitazone. Results: HFD-fed miR-34a−/− mice were significantly heavier with a greater increase in eWAT weight than WT. miR-34a−/− eWAT had a smaller adipocyte area, which significantly increased with HFD. miR-34a−/− eWAT showed basal increases in Cd36, Hmgcr, Lxrα, Pgc1α, and Fasn. miR-34a−/− intrascapular brown adipose tissue had basal reductions in c/ebpα and c/ebpβ, with in vitro miR-34a−/− white adipocytes showing increased lipid content. An F4/80high macrophage population was present in HFD miR-34a−/− eWAT, with increased IL-10 transcripts and serum IL-5 protein. Finally, miR-34a−/− bone marrow-derived macrophages showed an ablated CXCL1 response to tumor necrosis factor-α. Conclusions: These findings suggest a multifactorial role of miR-34a in controlling susceptibility to obesity, by regulating inflammatory and metabolic pathways

    Sustainable digitalization using self-dehydrating breathers

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    One of the most important accessories on a transformer is the transformer breather. Breathers help extend the technical life expectancy of the transformer by keeping the moisture inside the transformer at a normal level. Currently, there are two types of breathers available on the market — conventional and self-dehydrating breathers (SDBs). These are also known as smart breathers or maintenance-free breathers. Many asset engineers have realized the technical benefits of the shift from conventional breathers to SDBs; however, the main stumbling block to widespread usage is convincing the commercial team members of the economic benefits gained by installing SDBs. In this article, an investigation on the return on investment for SDBs is presented, along with the reduction of associated kgCO2e emissions due to the use of SDBs
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