Dietary stearic acid reduces plasma and hepatic cholesterol concentrations without increasing bile acid excretion in cholesterol-fed hamsters

Although there is general agreement that saturated fatty acids elevate plasma cholesterol concentrations, the relative effects of individual fatty acids on cholesterol and bile acid metabolism are less clear. In this study, cholesterol and bile acid responses to diets enriched in different saturated fatty acids were investigated in hamsters. The six diets examined were as follows: 5% fat (g/100 g) enriched in palmitic acid (16:0) with no cholesterol, 5% fat 16:0-enriched, 0.05% cholesterol (wt/wt), and four diets containing 0.05% cholesterol and 15% fat with each diet enriched in lauric (12:0), myristic (14:0), palmitic (16:0), or stearic acid (18:0). Total plasma cholesterol concentration was significantly greater in hamsters fed the 14:0-enriched diet relative to those fed the 18:0-enriched diet (P < 0.05). Both plasma and liver cholesterol concentrations of hamsters fed 18:0 did not differ from those of the group fed no dietary cholesterol. In all instances, differences in total plasma cholesterol were accounted for within the HDL fraction; no significant treatment differences in VLDL or LDL cholesterol were found. Total daily fecal bile acid excretion was higher in hamsters fed the 15% fat 16:0 diet compared with those fed no dietary cholesterol (P < 0.05), but not significantly different from other treatment groups. There was greater deoxycholic acid excretion (P < 0.05) from hamsters fed the 14:0 and 16:0 diets compared with those fed the 18:0-enriched diet. Small intestinal + gallbladder bile acids, an index of pool size, did not differ significantly among the groups. The observed relative hypocholesterolemic effect of stearic acid was not mediated by increased bile acid excretion.     

Benchmarking Iterative Receivers for BICM Multi-Carrier Systems Against Capacity Bounds

In this paper, we analyze iterative receivers for bit-interleaved coded modulation (BICM) multi-carrier systems and compare them against theoretical capacity bounds for the channel, coded modulation, and BICM. We map the theoretical capacity bounds into bit-error rate (BER) versus average signal-to-noise ratio per bit plots to simplify the comparison between the theoretical capacity bounds and simulated BER curves. As BER simulations show, iterative receivers with code doping or spreading reach the turbo-cliff within 1 or 0.3dB of the independent Rayleigh fading channel capacity. While the iterative receiver with spreading is closer to the channel capacity than the one with code doping, the later one can eliminate the residual bit-errors after the turbo-cliff. We further present a combinatorial analysis of the distribution of the spread symbol constellation for Walsh-Hadamard spreading codes used in a BICM multi-carrier system to explain the above results.     

Acute exposure to hair bleach causes airway hyperresponsiveness in a rabbit model

Ammonium persulphate (APS) and hydrogen peroxide (H2O2) are used as oxidants in many industrial processes and are the main constituents of standard hair bleaching products. In a previous study, it was demonstrated that aerosols of APS induce alterations in airway responsiveness. The present study examined whether exposure for 4 h to a hair bleach composition (containing APS, potassium persulphate and H2O2) or H2O2 could induce airway hyperresponsiveness and/or an obstructive ventilation pattern in a rabbit model. Exposure to the aerosols altered neither baseline airway resistance, dynamic elastance, slope of inspiratory pressure generation nor arterial blood pressure and blood gas measurements. Similarly to APS, hair bleach aerosols containing > or =10.9 mg x m(-3) persulphate (ammonium and potassium salt) in air and > or =1.36 mg x m(-3) H2O2 in air caused airway hyperresponsiveness to acetylcholine after 4 h of exposure. Aerosolized H2O2 (> or =37 mg x m(-3) in air) did not influence airway responsiveness to acetylcholine. The results demonstrate that hair bleaching products containing persulphates dissolved in H2O2 cause airway hyperresponsiveness to acetylcholine in rabbits.     

Components of hair bleaches as triggers of bronchial hypersensitivity--studies using a model for occupationally-induced lung damage

Ammonium persulfate (APS) is used as an oxidant in many industrial branches and is contained in bleaching substances used in hair cosmetic industry. In addition to skin diseases, respiratory disorders have been frequently reported. We examined whether APS can induce bronchial hyperresponsiveness (BHR) which has to be regarded as a first step in the development of obstructive respiratory disorders. In a rabbit model we tested the influence of aerosolized APS-solutions in concentrations of 0.1, 0.01 and 0.001 M (50, 5, 0,5 ppm in air) for about four hours on the contractile bronchial reaction. Exposure to APS-aerosols does not alter basal airway Resistance (RI), dynamic Elastance (Edyn), slope of inspiratory pressure generation (delta Poes/tI), arterial blood pressure and blood gases (PaO2, PaCO2). Before, after two and after four hours the influence of APS application on the bronchial reactivity to 0.2%- and 2% acetylcholine-aerosols (ACH) was tested. Exposure to an aerosol from 0.1 M APS solution, which is equivalent to a concentration of 50 ppm APS in air for two hours induces a significant increase in bronchoconstrictory responses to ACH. A nebulized 0.01 M APS solution causes an increased ACH response after four hours of exposure. However, inhalation of 0.001 M APS (0.5 ppm in air) does not alter sensitivity to ACH within four hours of exposure. In bronchoalveolar lavage an increased number of inflammatory cells was found. Our results demonstrate, aerolized APS-solutions to cause bronchial hyper-responsiveness after few hours of exposure presumably under the participation of inflammatory cells.     

Requirements and Algorithms for Cooperation of Heterogeneous Radio Access Networks

This paper defines the requirements for cooperation of heterogeneous radio access networks (RANs) and proposes a novel radio resource management (RRM) framework for support of mobility and quality of service (QoS) in a heterogeneous communication environment comprising IMT-Advanced and legacy systems. The reference IMT-Advanced system is the one developed within the IST project WINNER (IST-2003-507581 Project Wireless Initiative New Radio, ). The RRM mechanisms are evolved from traditional ones to comply with the requirements imposed by a simplified new (RAN) architecture as proposed for IMT-Advanced systems. The RRM mechanisms are evaluated for the scenario of intra-RAN and inter-RAN user mobility. The RRM framework incorporates as novelty improved triggering mechanisms, a network-controlled mobility management scheme with policy enforcement on different levels in the RAN architecture, and a distributed handover and admission control mechanism for fast decision polling at different levels of the RAN. The RRM framework is further enhanced with computational intelligence based on fuzzy logic algorithms to enhance the process of handover. The RRM framework has been evaluated in terms of reduced user blocking probabilities.

A high-performance,disposable screen-printed carbon electrode modified with multi-walled carbon nanotubes/graphene for ultratrace level electrochemical sensors

Journal of Applied Electrochemistry - In this work, a screen-printed carbon paste electrode (SPCE) combined with multi-walled carbon nanotubes (MCNT) and graphene (GP) in different mixing ratios...     

An externally driven magnetic microstirrer

In this paper, an inexpensive, easy-to-fabricate active magnetic mixer is presented. This mixer functions on top of a common magnetic stir plate and is capable of mixing two streams, each at flow rates up to 5 ml min(-1). A liquid-phase photopolymerization technique is used to fabricate the device. An analysis of mixing efficiency is based on greyscale intensity measurements of two coloured streams passing through the mixer. A brief hypothesis of the mechanism of mixing is also presented.     

Poly(di(ω-alkylphenyl)stannane)s

Poly(di(ω-alkylphenyl)stannane)s, [Sn(C _n H_2n Ph)₂] _m with n = 2–4, and a copolymer of di(3-propylphenyl)stannane and dibutylstannane of weight-average molar masses of 2–8 · 10⁴ g/mol were synthesized by dehydropolymerization of stannanes of the composition H₂SnR₂ using Wilkinson’s catalyst [RhCl(PPh₃)₃]. At least two methylene groups were required as spacers between the phenyl group and the tin atom for polymerization to occur. The polystannanes were characterized by, among other techniques, ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopy, thermal analysis and X-ray diffraction. The polymers featured properties different from those of the corresponding poly(dialkylstannane)s. Specifically, the [Sn(C _n H_2n Ph)₂] _m family displayed glass transitions at remarkably low temperatures, down to ca. −50 °C, and a lower value for a copolymer (−68 °C). Polymers [Sn(C_nH_2nPh)₂]_m with n = 2 and 3 and a copolymer at room temperature were of a gel-like concistence, which enabled facile orientation with shear forces. Finally, the temperature-dependent electrical conductivity was determined for poly(di(3-propylphenyl)stannane), which followed the law of typical semiconductors, with an activation energy for conduction of 0.12 eV.