Does green tea affect postprandial glucose,insulin and satiety in healthy subjects: a randomized controlled trial

Background  

Results of epidemiological studies have suggested that consumption of green tea could lower the risk of type 2 diabetes. Intervention studies show that green tea may decrease blood glucose levels, and also increase satiety. This study was conducted to examine the postprandial effects of green tea on glucose levels, glycemic index, insulin levels and satiety in healthy individuals after the consumption of a meal including green tea.     

Spatio‐temporal analysis and modeling of short‐term wind power forecast errors

Forecasts of wind power production are increasingly being used in various management tasks. So far, such forecasts and related uncertainty information have usually been generated individually for a given site of interest (either a wind farm or a group of wind farms), without properly accounting for the spatio‐temporal dependencies observed in the wind generation field. However, it is intuitively expected that, owing to the inertia of meteorological forecasting systems, a forecast error made at a given point in space and time will be related to forecast errors at other points in space in the following period. The existence of such underlying correlation patterns is demonstrated and analyzed in this paper, considering the case‐study of western Denmark. The effects of prevailing wind speed and direction on autocorrelation and cross‐correlation patterns are thoroughly described. For a flat terrain region of small size like western Denmark, significant correlation between the various zones is observed for time delays up to 5 h. Wind direction is shown to play a crucial role, while the effect of wind speed is more complex. Nonlinear models permitting capture of the interdependence structure of wind power forecast errors are proposed, and their ability to mimic this structure is discussed. The best performing model is shown to explain 54% of the variations of the forecast errors observed for the individual forecasts used today. Even though focus is on 1‐h‐ahead forecast errors and on western Denmark only, the methodology proposed may be similarly tested on the cases of further look‐ahead times, larger areas, or more complex topographies. Such generalization may not be straightforward. While the results presented here comprise a first step only, the revealed error propagation principles may be seen as a basis for future related work. Copyright © 2010 John Wiley & Sons, Ltd.     

Structural Analysis,Electrochemical Behavior,and Biocompatibility of Novel Quaternary Titanium Alloy with near β Structure

This article analyses the microstructure, electrochemical behavior, and biocompatibility of a novel Ti-20Nb-10Zr-5Ta alloy with low Young’s modulus (59 GPa) much closer to that of bone, between 10 and 30 GPa, than Ti and other Ti alloys used as implant biomaterial. XRD and SEM measurements revealed a near β crystalline microstructure containing β phase matrix and secondary α phase, with a typical grain size of around 200 μm. The corrosion behavior in neutral Ringer solution evidenced: self-passivation behavior characterizing a very resistant passive film; an easy passivation as a result of favorable influence of the alloying elements Nb, Zr, and Ta that participate with their passive oxides to the formation of the alloy passive film; low corrosion and ion release rates corresponding with very low toxicity. In MEM solution, the novel alloy demonstrated very high corrosion resistance and no susceptibility to localized corrosion. Biocompatibility was evaluated on in vitro human osteoblast-like and human immortalized pulmonary fibroblast cell (Wi-38) lines and the new Ti-20Nb-10Zr-5Ta alloy exhibited no cytotoxicity. The new Ti-20Nb-10Zr5Ta alloy is a promising material for implants due to combined properties of low elastic modulus, very low corrosion rate, and good biocompatibility.     

Comparative Study of Reactive Dyes Oxidation by H2O2/UV,H2O2/UV/Fe2+ and H2O2/UV/Fe° Processes

The decolorization and mineralization of two reactive dyes C.I. Reactive Blue 4 (RB 4) and C.I. Reactive Blue 268 (RB 268) were studied using various advanced oxidation processes (AOPs) such as H₂O₂/UV, H₂O₂/UV/Fe²⁺, and the H₂O₂/UV/Fe°. All processes were performed within a laboratory-scale photo-reactor setup. The experimental results were assessed in terms of absorbance (A) and total organic carbon (TOC) reduction. The main degradation products were identified by high resolution gas chromatography/high resolution mass spectrometry analyses. The results of our study demonstrated that the additions of moderate concentrations of H₂O₂ and Fe catalyst during the AOPs evidently increased the decolorization efficiencies within the first few minutes of the processing time (5–10 min) for both tested dyes, and prolonged irradiation does not necessarily significantly improve decolorization. On contrary, TOC removal rate increased with the processing time and with the addition of the catalyst from 40–50% up to 70–80% at defined experimental conditions. All the tested AOPs were very successful methods for RB 268 decolorization, having very complex structure and much higher molecular weight compared to the dye RB 4. This is important from both economic and ecological points of view.     

Short‐term hydropower planning coordinated with wind power in areas with congestion problems

In this paper, a day‐ahead planning algorithm for a multi‐reservoir hydropower system coordinated with wind power is developed. Coordination applies to real situations, where wind power and hydropower are owned by different utilities, sharing the same transmission lines, although hydropower has priority for transmission capacity. Coordination is thus necessary to minimize wind energy curtailments during congestion situations. The planning algorithm accounts for the uncertainty of wind power forecast. Only planning for the spot market is considered. Once the production bid is placed on the market, it cannot be changed. The solution of the stochastic optimization problem should, therefore, fulfill the transmission constraints for all wind power production scenarios. An evaluation algorithm is also developed to quantify the impact from the coordinated planning in the long run. The developed planning algorithm and the evaluation algorithm are applied in a case study. The results are compared with uncoordinated operation. The results of the case study show that coordination with wind power brings additional income to the hydropower utility and leads to significant reduction of wind energy curtailments. Copyright © 2007 John Wiley & Sons, Ltd.     

The influence of distribution and deposit of conductive coating on shielding effectiveness of textiles

This study presents the investigation of electrically conductive fabrics with low resistivity, coated with formulation containing the conjugated polymer system – poly(3,4-ethylenedioxythiophene)-polystyrene sulphonate (PEDOT-PSS). The samples of fabrics were coated with PEDOT-PSS, using a screen printing method, by different patterns or coating their surface fully with different coating deposit. Methods for measurement of electrostatic properties, reflection and transmission as well as the assessment of electromagnetic radiation (EMR) shielding effectiveness were used for the characterization of electrical properties of developed samples. EMR shielding properties were investigated within 2–12 GHz frequency bands. The highest attenuation of the electromagnetic energy among tested fabrics was obtained on the fabrics fully coated with paste and it depended on deposit considerably. The influence of distribution and deposit of conductive coating on shielding effectiveness of textiles were determined. Correlation between shielding effectiveness and electrostatic properties of developed coated fabrics was also discussed. Electrical properties of samples coated with formulation containing PEDOT-PSS were compared with these of fabrics with metalized yarns, developed by us earlier. The results of EMR shielding measurements showed that fabrics coated with the paste containing conductive polymer system compared to fabrics with in-weaved conductive metalized yarns have certain advantages as EMR shields.     

Formation and characterization of melt-spun polypropylene fibers with propolis for medical applications

The search of possibilities to improve the functional properties of textile materials has been continuing for years with the aim to provide higher hygiene characteristics offer advanced therapeutic functionality. One of available approaches to provide new properties for textiles is the inclusion of natural ingredients. Propolis extracts are successfully used in practical therapeutics for accelerated wound healing and cell proliferation processes. In this study, pure multi-filament yarns and yarns saturated with propolis were developed and characterized. The effect of preparation and formulation parameters on the characteristics of yarns was evaluated; the release of propolis extract components from yarns and their possible cytotoxicity on cell formation was also determined.     

On another view of an inverse of an interval matrix

We consider n × n matrix whose elements are fuzzy numbers (hereinafter a fuzzy matrix) and we introduce notions of regularity of a fuzzy matrix and the inverse matrix of a fuzzy matrix (hereinafter the fuzzy inverse) in this paper. It is shown that the fuzzy inverse is a fuzzy matrix as well. Also we pay attention to the calculation of the fuzzy inverse in a special case. Main results are based on Rohn’s results in the field of linear problems with inexact data.     

Fine structure and related properties of the assembleable carbon nanotubes based electrode for new family of biosensors with chooseable selectivity

Surfaces of constituent parts of biosensors based on single wall carbon nanotube layer were investigated and compare for properly functioning and faulty biosensors. Though the original technology is acceptable for changing of the selectivity, only glucose sensitive biosensors are investigated. Based on the results of the study, a correlation between the features of the nanoscale structures and parameters of amperiometric biosensors for assemblage of which an innovative approach is described. Original template of the electrodes has been prepared on a base of single wall carbon nanotube layer deposited on the supporting polycarbonate membrane. Original immobilisation of enzymes within special membrane allows functional modification of biosensors being accomplished by simple replacement of the enzymatic membrane. The original technology leads to a novel family of biosensors acceptable for detection of wide range of carbohydrates. The morphology and the local electric properties of the constituent parts of the biosensors are characterized by scanning probe microscopy. The sensitivity, selectivity and stability are described for typical types of the biosensors.