Effects of non-fermented tea extracts on in vitro digestive hydrolysis of lipids and on cholesterol precipitation

Extracts of non-fermented teas precipitated cholesterol and decreased dialysability of lipids in an in vitro model that simulated digestion in humans. The efficiency of tea extracts was affected by catechins and mainly by EGCG, ECG, GCG and CG. Total amounts and concentrations of individual catechins in extracts depended strongly on the tea brands. There were significant relationships between amounts of dialysable products of triglyceride hydrolysis, amounts of precipitated cholesterol, and concentrations of individual catechin gallates in tea brews. Dialysability of lipids was effectively reduced by tea extracts high in GCG and CG. Dialysability of lipids was strongly correlated with the sum of GCG and CG (R ² = 84.64%) whereas precipitation of cholesterol was highly correlated with total amounts of catechin gallates in the tea extracts (R ² = 89.59%).     

Antimicrobial potential and chemical composition of Mentha piperita oil in liquid and vapour phase against food spoiling microorganisms

Antimicrobial potential of Mentha piperita oil in liquid and vapour phase against different bacterial strains (Escherichia coli αDH5, Escherichia coli ATCC 25922, Pseudomonas aeruginosa, Pseudomonas fluorescens, Bacillus subtilis and Staphylococcus aureus), fungal strains (Penicillium digitatum, Aspergillus flavus, Aspergillus niger, Mucor spp, and Fusarium oxysporum) and yeasts (Candida albicans and Sacchromyces cerevisiae) was determined by agar dilution method, well diffusion method and disc volatilization method, respectively. Minimum inhibitory concentration (MIC) and Minimum bactericidal and fungicidal concentration (MBC/MFC) of M. piperita oil varied from 1.13 to 2.25 mg/ml and 2.25 to 9 mg/ml for bacterial strains, 1.13 to 2.25 mg/ml and 2.25 to 4.5 mg/ml for fungal strains and 1.13 mg/ml and 2.25 mg/ml for yeasts, respectively. Bacterial inhibition zone due to M. piperita oil (40 μl/well) varied from 13 mm (P. aeruginosa) to 22 mm (B. subtilis). Bacterial inhibition zone due to M. piperita oil (40 μl) vapour varied from 22 mm (P. fluorescens) to 35 mm (B. subtilis) while almost complete growth inhibition occurred in case of fungal strains. In the kill time assays, 100% reduction in viability of C. albicans and B. subtilis was found within 8 h exposure to M. piperita oil vapour. Significant morphological alterations due to the effect of M. piperita oil and oil vapour on B. Subtilis have also been observed by scanning electron microscope.Chemical constituents of the M. piperita essential oil and oil vapour have been identified by gas chromatography (GC), gas chromatography/mass spectrometry (GC–MS) and Solid phase micro extraction-gas chromatography mass spectrometry (SPME GC–MS), respectively.     

Cyclic delay diversity with bit-interleaved coded modulation in orthogonal frequency division multiple access

We consider cyclic delay diversity in OFDMA. Cyclic delay diversity is an elegant way to obtain spatial diversity in an FEC coded OFDM system without exceeding the guard interval. We first address the problem of choosing the cyclic delays and propose a new robust design rule which enables to pick up the full spatial and frequency diversity which is inherent in a frequency-selective MIMO channel. Our choice of cyclic delays has consequences for the interleaving and multiple access scheme since the spatial diversity appears to be transformed into frequency diversity between neighbouring subcarriers. Therefore, a system with a conventional block frequency interleaver will fail to exploit the spatial diversity. We propose an interleaving and multiple access strategy which guarantees that all users obtain the maximum possible diversity advantage using FEC codes with a limited constraint length. Furthermore, we provide a performance comparison to transmit diversity from orthogonal designs.     

High Power Factor of HPHT-Sintered GeTe-AgSbTe<Subscript>2</Subscript> Alloys

The thermopower and electrical resistivity of alloys of GeTe and AgSbTe₂ (TAGS) sintered at high pressure (up to 4.5 GPa) and high temperature (HPHT) have been studied from 300 K to 750 K. An apparatus for measuring thermopower and electrical resistivity at temperatures >300 K is described. The linear temperature dependence of thermopower and electrical conductivity indicates that these materials are likely to be degenerate semiconductors. At a sintering pressure of 4.0 GPa, the calculated power factor shows a steady progression, reaching a maximum at a sintering temperature of 800°C, with a subsequent decrease at the highest sintering temperature of 850°C. The maximum power factor of 4.32 × 10⁻³ W m⁻¹ K⁻² at ~675 K is ~25% higher than reported values. These results illustrate that HPHT processing is a feasible and controllable way of tuning the properties of thermoelectric materials.     

HRV scaling exponent identifies postinfarction patients who might benefit from prophylactic treatment with amiodarone

Analysing the Holter recordings collected at baseline during the European Myocardial Infarction Amiodarone Trial (EMIAT), we evaluate the possibility of using alpha, the slope of the power spectrum of heart rate variability signals (HRV) in the vicinity of f = 0, for postinfarction risk stratification. We found no relevant difference in the values of alpha for the placebo population. On the contrary, in the amiodarone arm, the distinction in the survival rates of those with high or low alpha-values was highly significant. Moreover, high risk patients with respect to alpha (higher values) did not seem to benefit from amiodarone. The results suggest that alpha might convey physiologic information that is different than what is expressed by other HRV characteristics, such as the triangular index. When combining high risk patients in term of triangular index (<20) and low risk patients with respect to alpha (相似文献   

Surface wind speed reconstruction from synoptic pressure fields: machine learning versus weather regimes classification techniques

This paper tackles a problem of surface wind speed reconstruction based on synoptic‐scale meteorological fields. Specifically, two different approaches are discussed and compared: a pure Machine Learning method, formed by a Support Vector Regression and a genetic algorithm that only considers synoptic pressure as input variable, and a Weather Regimes Classification Technique, based on a k‐means clustering of the main three principal components of the geopotential height field and a simple, but efficient, linear regression between the surface pressure gradient and the observed surface wind. Both algorithms are shown to be accurate enough for wind speed reconstruction at medium latitude regions, even when there are only a few years of observations. These methodologies can also be used for filling gaps in wind speed series and, with some modifications and further research, they could be used for wind speed forecasting. The algorithms proposed are fully described and compared in this paper, and their performance has been comparatively evaluated in several real problems of wind speed reconstruction at three sites (Cabauw (The Netherlands), Capel (Wales, UK) and Kaegnes (Denmark)), obtaining excellent results in terms of wind speed reconstruction with moderate complexity in data processing and algorithms. Copyright © 2014 John Wiley & Sons, Ltd.     

Optimum tilt angle and orientation for solar collector in Brunei Darussalam

One of the important parameters that affects the performance of a solar collector is its tilt angle with the horizontal. This is due to the fact that the variation of tilt angle changes the amount of solar radiation reaching the collector surface. A mathematical model was used for estimating the total (global) solar radiation on a tilted surface, and to determine the optimum tilt angle and orientation (surface azimuth angle) for the solar collector in Brunei Darussalam on a daily basis, as well as for a specific period. The optimum angle was computed by searching for the values for which the total radiation on the collector surface is a maximum for a particular day or a specific period. The results reveal that changing the tilt angle 12 times in a year (i.e. using the monthly-averaged optimum tilt angle) maintains approximately the total amount of solar radiation near the maximum value that is found by changing the tilt angle daily to its optimum value. This achieves a yearly gain in solar radiation of 5% more than the case of a solar collector fixed on a horizontal surface.     

A framework to assess plan implementation maturity with an application to flood management in Vietnam

Implementation failure is a long-known Achilles’ heel of water and flood management plans. Contemporary planning approaches address the implementation challenge by using more participatory planning processes to ensure support for plans, assuming that this support will also benefit plan implementation. A proactive analysis of possible implementation issues during the planning stage is not yet common. This paper introduces a framework based on the motivation and ability of actors, supported by concepts of triggers, threats and opportunities. A case application for flood management in Ho Chi Minh City, Vietnam, demonstrates the use of this motivation-ability framework to assess plan implementation maturity.     

Software agent-based directed diffusion in wireless sensor network

In an environment where node density is massive, placement is heterogeneous and redundant sensory traffic is produced; limited network resources such as bandwidth and energy are hastily consumed by individual sensor nodes. Equipped with only a limited battery power supply, this minimizes the lifetime of these sensor nodes. At the network layer, many researchers have tackled this issue by proposing several energy efficient routing schemes. All these schemes tend to save energy by elevating redundant data traffic via in-network processing and choosing empirically good and shortest routing paths for transfer of sensory data to a central location (sink) for further, application-specific processing. Seldom has an attempt been made to reduce network traffic by moving the application-specific code to the source nodes. We unmitigated our efforts to augment the node lifetime within a sensor network by introducing mobile agents. These mobile agents can be used to greatly reduce communication costs, especially over low bandwidth links, by moving the processing function to the data rather than bringing the data to a central processor. Toward this end, we propose an agent-based directed diffusion approach to increase sensor node efficiency and we present the experimental results.     

Borax‐Mediated Formation of Carbon Aerogels from Glucose

Hierarchically structured carbon aerogels are produced in a simple, rapid, efficient, and sustainable hydrothermal approach, using only glucose as the carbon precursor. Using sodium borate (borax) as a novel complex structure directing agent nanostructured, carbon monoliths, structurally similar to the well‐known sol‐gel monoliths made of silica are obtained. Experimental results indicate the acetalization reaction of monosaccharides with their dehydration product hydroxymethylfurfural to be very important and inhibiting in the process of hydrothermal carbonization. Addition of borax, leads to a competitive complexation of diols, resulting in promising secondary catalytic effect with regard to carbon yield. Accordingly, it is shown that the sugar:borax ratio directs the primary carbon nanoparticle size into the sub ?50 nm range, while their spinodal destabilization ultimately results in the controlled aggregation of carbonaceous particles leading to the formation of monoliths in a simple one step hydrothermal process. Post‐synthesis thermal carbonization is also used to increase surface area to the medium‐high range, introducing electric conductivity into the carbon monoliths. The resulting materials are promising candidates for applications in flash chromatography, for fast adsorption/purifications, and as porous conductive electrodes.