133 research outputs found

    Dielectric properties measurements of brown and white adipose tissue in rats from 0.5 to 10 GHz

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    Brown adipose tissue (BAT) plays an important role in whole body metabolism and with appropriate stimulus could potentially mediate weight gain and insulin sensitivity. Although imaging techniques are available to detect subsurface BAT, there are currently no viable methods for continuous acquisition of BAT energy expenditure. Microwave (MW) radiometry is an emerging technology that allows the quantification of tissue temperature variations at depths of several centimeters. Such temperature differentials may be correlated with variations in metabolic rate, thus providing a quantitative approach to monitor BAT metabolism. In order to optimize MW radiometry, numerical and experimental phantoms with accurate dielectric properties are required to develop and calibrate radiometric sensors. Thus, we present for the first time, the characterization of relative permittivity and electrical conductivity of brown (BAT) and white (WAT) adipose tissues in rats across the MW range 0.5-10GHz. Measurements were carried out in situ and post mortem in six female rats of approximately 200g. A Cole-Cole model was used to fit the experimental data into a parametric model that describes the variation of dielectric properties as a function of frequency. Measurements confirm that the dielectric properties of BAT (εr = 14.0-19.4, σ = 0.3-3.3S/m) are significantly higher than those of WAT (εr = 9.1-11.9, σ = 0.1-1.9S/m), in accordance with the higher water content of BAT

    Localisation humérale d’une tumeur à cellules géantes récidivantes (à propos d’un cas)

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    Les auteurs rapportent un cas de localisation rare d'une tumeur à cellules géantes au niveau de la palette humérale du coude droit chez unmilitaire de 36 ans de sexe masculin, la radio standard montrait une image kystique ne soufflant pas la corticale. L'examen anatomo-pathologiquea permis d' établir le diagnostic et le traitement a fait appel: au début a une Exérèse chirurgicale totale et une greffe osseuse par un greffon iliaquede la totalité de la palette huméral qui s'est compliquée à 6 mois de recule d une récidive locale

    Optimal Operation of Micro-grids Considering the Uncertainties of Demand and Renewable Energy Resources Generation

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    Nowadays, due to technical and economic reasons, the distributed generation (DG) units are widely connected to the low and medium voltage network and created a new structure called micro-grid. Renewable energies (especially wind and solar) based DGs are one of the most important generations units among DG units. Because of stochastic behavior of these resources, the optimum and safe management and operation of micro-grids has become one of the research priorities for researchers. So, in this study, the optimal operation of a typical micro-grid is investigated in order to maximize the penetration of renewable energy sources with the lowest operation cost with respect to the limitations for the load supply and the distributed generation resources. The understudy micro-grid consists of diesel generator, battery, wind turbines and photovoltaic panels. The objective function comprises of fuel cost, start-up cost, spinning reserve cost, power purchasing cost from the upstream grid and the sales revenue of the power to the upstream grid. In this paper, the uncertainties of demand, wind speed and solar radiation are considered and the optimization will be made by using the GAMS software and mixed integer planning method (MIP).Article History: Received May 21, 2016; Received in revised form July 11, 2016; Accepted October 15, 2016; Available onlineHow to Cite This Article: Jasemi, M., Adabi, F., Mozafari, B., and Salahi, S. (2016) Optimal Operation of Micro-grids Considering the Uncertainties of Demand and Renewable Energy Resources Generation, Int. Journal of Renewable Energy Development, 5(3),233-248.http://dx.doi.org/10.14710/ijred.5.3.233-24

    Prevalence of chronic kidney disease and its associated risk factors: The first report from Iran using both microalbuminuria and urine sediment

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    Background: The incidence of major risk factors of chronic kidney disease (CKD) in the world is on the rise, and it is expected that this incidence and prevalence, particularly in developing countries, will continue to increase. Using data on urinary sediment and microalbuminuria, we aimed to estimate the prevalence of CKD in northeast Iran. Methods: In a cross-sectional study, the prevalence of CKD in a sample of 1557 regionally representative people, aged � 18 years, was analyzed. CKD was determined based on glomerular filtration rate (GFR) and microalbuminuria. Life style data, urine and blood samples were collected. Urine samples without any proteinuria in the initial dipstick test were checked for qualitative microalbuminuria. If the latter was positive, quantitative microalbuminuria was evaluated. Results: 1557 subjects with a mean age of 56.76 ± 12.04 years were enrolled in this study. Based on the modifcation of diet in renal disease (MDRD) equation, 137 subjects (8.89%) were categorized as CKD stages III-V. Based on urine abnormalities, the prevalence of combined CKD stages I and II was 10.63%, and based on macro- and microalbuminuria it was 14.53%. The prevalence of CKD was significantly associated with sex, age, marital status, education, diabetes mellitus (DM), hypertension (HTN), ischemic heart disease (IHD), waist to hip ratio, myocardial infarction (MI), and cerebrovascular accident (CVA). Conclusion: CKD and its main risk factors are common and represent a definite health threat in this region of Iran. Using and standardizing less expensive screening tests in low resource countries could be a good alternative that may improve the outcome through early detection of CKD

    Evaluation of the critical success factors (CSFs) in selecting building contractors using pareto analysis and the analytical hierarchy process

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    The purpose of this paper is to obtain a set of critical success factors (CSFs) for selecting building contractors in Qatar to help investors effectively and efficiently build their houses. First, a systematic review of the previous research was carried out to capture the 20 most frequently occurring CSFs for constructing houses. Then, a survey was distributed to 280 investors to determine their perceptions of the importance of CSFs. The survey was evaluated using Pareto analysis and the analytical hierarchy process (AHP) to determine which CSFs are most relevant to investors when building houses. The contribution of this study to the current knowledge is studying the investor’s behavior by considering frequency, cost, and time components simultaneously to capture the most significant Critical Success Factors (CSFs) in selecting building contractors. The strategy developed by this study provides a ready set of criteria that can be used by investors and local authorities in qualifying building contractors

    In vitro Anti-proliferative and Apoptotic Activities of Eurycoma longifolia Jack (Simaroubaceae) on HL-60 Cell Line

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    Purpose: To investigate the anti-proliferative, apoptotic and differentiating activities of Eurycoma longifolia root extracts on HL-60 leukemic cells.Methods: HL-60 cells were treated with different partially purified sub-fractions (F1 – F3) derived from the resin chromatography of the crude methanol root extract of E. longifolia roots, at different doses andtime points. The anti-proliferative activity of E. longifolia was assessed via cell counting and trypan blue exclusion. Apoptosis was evaluated via Annexin-V FITC/IP and Hoechst staining. Flow cytometry and Wright staining were used to assess its differentiation activities.Results: F1 showed unremarkable growth inhibition rate while F2 and F3 showed growth inhibitory effects with median inhibitory concentration (IC50) values of 15.2 and 28.6 ìg/ml, respectively. Treatment with F2 and F3 (100 ìg/ml) for 96 h increased cell death from 3.3 to 95.5 and 76.3 %,respectively. Treatment with F2 (50 ìg/ml) induced apoptosis by 14, 19.5 and 25 % after 24, 48 and 72 h, respectively. No differentiation activity was observed, as indicated by absence of myeloid maturation and a non-significant CD14 positivity (p > 0.05).Conclusion: E. longifolia extract (F2) showed promising anti-leukemic activity and can be a candidate for the development of a drug for the treatment of acute promyelocytic leukemia (APL).Keywords: Acute promyelocytic leukemia (APL), HL-60 cells, Eurycoma longifolia, Apoptosis, Antiproliferation, Differentiatio

    Numerical 3D modeling of heat transfer in human tissues for microwave radiometry monitoring of Brown fat metabolismo

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    Background: Brown adipose tissue (BAT) plays an important role in whole body metabolism and could potentially mediate weight gain and insulin sensitivity. Although some imaging techniques allow BAT detection, there are currently no viable methods for continuous acquisition of BAT energy expenditure. We present a non-invasive technique for long term monitoring of BAT metabolism using microwave radiometry. Methods: A multilayer 3D computational model was created in HFSS™ with 1.5 mm skin, 3-10 mm subcutaneous fat, 200 mm muscle and a BAT region (2-6 cm3) located between fat and muscle. Based on this model, a log-spiral antenna was designed and optimized to maximize reception of thermal emissions from the target (BAT). The power absorption patterns calculated in HFSS™ were combined with simulated thermal distributions computed in COMSOL® to predict radiometric signal measured from an ultra-low-noise microwave radiometer. The power received by the antenna was characterized as a function of different levels of BAT metabolism under cold and noradrenergic stimulation. Results: The optimized frequency band was 1.5-2.2 GHz, with averaged antenna efficiency of 19%. The simulated power received by the radiometric antenna increased 2-9 mdBm (noradrenergic stimulus) and 4-15 mdBm (cold stimulus) corresponding to increased 15-fold BAT metabolism. Conclusions: Results demonstrated the ability to detect thermal radiation from small volumes (2-6 cm3) of BAT located up to 12 mm deep and to monitor small changes (0.5°C) in BAT metabolism. As such, the developed miniature radiometric antenna sensor appears suitable for non-invasive long term monitoring of BAT metabolism

    A pilot double-blind randomised placebo-controlled trial of the effects of fixed-dose combination therapy ('polypill') on cardiovascular risk factors

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    SummaryAim: Our objective was to investigate the effects and tolerability of fixed-dose combination therapy on blood pressure and LDL in adults without elevated blood pressure or lipid levels. Methods: This was a double-blind randomised placebo-controlled trial in residents of Kalaleh, Golestan, Iran. Following an 8-week placebo run-in period, 475 participants, aged 50 to 79 years, without cardiovascular disease, hypertension or hyperlipidaemia were randomised to fixed-dose combination therapy with aspirin 81 mg, enalapril 2.5 mg, atorvastatin 20 mg and hydrochlorothiazide 12.5 mg (polypill) or placebo for a period of 12 months. The primary outcomes were changes in LDL-cholesterol, systolic and diastolic blood pressure and adverse reactions. Analysis was by intention-to-treat basis. Results: At baseline, there were differences in systolic blood pressure (6 mmHg). Taking account of baseline differences, at 12 months, polypill was associated with statistically significant reductions in blood pressure (4.5/1.6 mmHg) and LDL-cholesterol (0.46 mmol/l). The study drug was well tolerated, but resulted in the modest reductions in blood pressure and lipid levels. Conclusion: The effects of the polypill on blood pressure and lipid levels were less than anticipated, raising questions about the reliability of the reported compliance. There is a case for a fully powered trial of a polypill for the prevention of cardiovascular disease. © 2010 Blackwell Publishing Ltd
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