Pro-Oxidant Effects of β-Carotene During Thermal Oxidation of Edible Oils

β-Carotene is one of the most important fat soluble pigments with well-known antioxidant and pro-vitamin A activity. It is used in industries as a food colorant and a source of vitamin A. The thermal induced degradation during processing of wide varieties of carotenoid-rich foods leads to color and properties losses. The thermal stability of edible oils is thus of great importance to food manufacturers. Corn oil, rapeseed, and sunflower oils were fortified with 50–300 μg/g of β-carotene and oxidized using a Rancimat apparatus (air flow rate 20 L/h) at 110 °C for 14 h. β-Carotene degradation was measured using high performance thin layer chromatography and confirmed by HPLC–DAD–MS. Triacylglycerols and polar compounds (PC) were determined using LC–ESI–MS. Results showed that most of the β-carotene was degraded during the first 5 h of the thermal oxidation. It was found that the addition of β-carotene produces significant effects (P < 0.05) on the peroxide index, free fatty acid values and radical scavenging activity of the three oils. Triacylglycerols containing high amounts of oleic acid show higher stability toward thermal oxidation and β-carotene treatment. Among the oils, rapeseed oil was the most stable oil in terms of the formation of polar compounds (PC), followed by corn oil, while sunflower oil was more prone to oxidation and thus higher amounts of PC were formed.     

Rearrangements of sp/sp hybridized bonding with phosphorus incorporation in pulsed laser deposited semiconducting carbon films by X-ray photoelectron spectroscopic analysis

The carbon films were grown on p-type silicon substrate at room temperature by pulsed (XeCl) laser deposition technique using camphoric carbon target containing 1%, 3%, 5% and 7% of phosphorus (P) by mass. The analysis of X-ray photoelectron spectroscopy spectra of the C1s region in these films shows the presence of sp² and sp³ hybridized carbon and a sp² satellite peak due to π–π shake up. The sp² content is seen to remain almost constant with P content. The FWHM of the sp² peak increases up to 5% P but decreases for 7% P probably due to clustering of sp² chains and this clustering in the sp² phase probably decreases the band gap for the 7% P film. With P incorporation, the tetrahedral bonding configurations of the carbon network do not change appreciably, therefore, suggesting the scope of phosphorus as a potential dopant in carbon films.     

Liquid fuels and chemicals from pyrolysis of motorcycle tire waste: Product yields,compositions and related properties

In this study, experiments have been conducted on the sample of solid motorcycle tire wastes to determine particularly the effect of temperature, feed size, and apparent vapor residence time on the pyrolysis product yields and their compositions. The maximum liquid yield of 49 wt.% was obtained at a final pyrolysis temperature of 475 °C, feed size 4 cm³, with a residence time of 5 s under N₂ atmosphere in a fixed-bed fire-tube heating reactor system. The pyrolysis liquid products were characterized by elemental analysis and various chromatographic and spectroscopic techniques. Chromatographic and spectroscopic studies on the liquids show that it can be used as liquid fuels and chemical feedstock, with a calorific value of 42.00 MJ/kg and empirical formula of CH_1.27O_0.025N_0.006.     

A single-chip tri-band (2100, 1900, 850/800 MHz) WCDMA/HSDPA cellular transceiver

This paper describes the design and performance of the first tri-band (2100, 1900, 800/850 MHz) single-chip 3G cellular transceiver IC for worldwide use. The transceiver has been designed to meet all narrowband blocker, newly proposed Adjacent Channel II, and Category 10 HSDPA (High Speed Downlink Packet Access) requirements. The design is part of a reconfigurable reference platform for multi-band, multi-mode (GSM/EDGE + WCDMA) radios. The zero-IF receiver is comprised of a novel multi-band quadrature mixer, seventh-order baseband filtering, and a novel DC offset correction scheme, which exhibits no settling time or peak switching transients after gain steps. The receiver lineup is designed to optimize HSDPA throughput and minimize sensitivity to analog baseband filter bandwidth variations. The direct-launch transmitter is made up of a third-order baseband filter, an I/Q modulator with variable gain, an integrated transformer, an RF variable gain amplifier, and a power amplifier driver. At +9.5-dBm output power, the transmitter achieves an error vector magnitude (EVM) of 4%. Fractional-N synthesizers achieve fast lock times of 50 /spl mu/s (150 /spl mu/s) within 20 ppm (0.1 ppm). Automatically calibrated, integrated VCOs achieve a 1.6-GHz tuning range to facilitate coverage over all six 3GPP frequency bands. The IC draws 34 mA in receive (18-mA receiver plus 16-mA fractional-N PLL/VCO) and 50 to 62 mA in transmit (-76 dBm to +9.5 dBm), including PLL/VCO, using a 2.775-V supply voltage. The RF transceiver is integrated with the baseband signal processing and associated passives in a 165-pad package, resulting in the first tri-band 3G radio transceiver with a digital interface which requires no external components.     

Diamond deposition onto WC-6%Co cutting tool material: coating structure and interfacial bond strength

Diamond coatings were grown on WC-6%Co cutting tool material. Measurements were carried out to investigate the effects of diamond seeding of the substrate before deposition, removal of cobalt from the substrate before deposition, and boron incorporation into the coating during growth on the growth rate, morphology and structure of the coating, and coating-substrate edhesion. Diamond seeding of the substrate resulted in a higher growth rate and diamond fraction of the coating relative to a polished and unseeded surface. Etching of cobalt from the substrate resulted in a higher growth rate, diamond fraction and adhesion strength relative to the unetched surface. Introduction of methanol into the gas phase led to a lower growth rate, diamond fraction and adhesion strength relative to the case when no methanol was injected. Introduction of boron oxide (B₂O₃) along with methanol into the gas phase did not affect the growth rate but increased both the diamond fraction and adhesion strength relative to the case when only methanol was added. It is believed that adhesion failure occurs at the diamond-substrate interface, possibly within a soft nanocrystalline graphite transition layer.     

Analysis of lossy planar transmission lines by using a vectorfinite element method

The vector finite element method with hybrid edge/nodal triangular elements is extended for the analysis of lossy planar transmission lines. In order to handle lossy conductor transmission lines, the present approach includes the effect of finite conductivity of a lossy area, and the dissipations in metallic conductors and dielectrics are calculated directly by considering a complex permittivity for the lossy region of interest. A propagation constant formulation is used in the FEM, which avoids spurious solutions absolutely and can handle sharp metal edges in inhomogeneous electromagnetic waveguides. Numerical examples are computed for microstrip lines, finlines, and triplate strip lines. The results obtained agree well with the earlier theoretical and experimental results, and thus show the validity of the method. Also, the current distributions on the lossy microstrip lines with finite strip thickness and isotropic substrates are presented     

Preparation of composites of polymer liquid crystal/cholesteric liquid crystal and their photochemical switching and memory properties by photoisomerization of a chiral azobenzene molecule

A chiral azobenzene compound was synthesized, and mixing the chiral azobenzene compound in a host nematic liquid crystal (LC) induced a cholesteric phase. The twisting power of the trans‐form of the chiral azobenzene compound was larger than that of its cis‐form produced by ultraviolet irradiation. A low molecular weight compensated nematic LC was then prepared by mixing of the chiral azobenzene and a nonphotochromic chiral compound, thus giving mutual opposite helical sense in the host LC. Reversible optical switching between transparent and opaque was achieved by ultraviolet and visible light irradiation. However, the photochemically switched opaque state was not stable even in the dark. Stability of the opaque state was found to be improved by adding polymer LC to the low molecular weight compensated nematic LC. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2577–2580, 2004     

Macrophages during fibrosis following scleral fistulising surgery in a rat model

BACKGROUND: The vasodilator effects of angiotensin converting enzyme inhibitors have been ascribed to systemic inhibition of the angiotensin II generation. However, local mechanisms of vasodilation also have been suggested. We tested whether the angiotensin converting enzyme inhibitor enalaprilat mediated local vasodilation in human dorsal hand veins. METHODS: We infused enalaprilat and assessed changes in dorsal hand vein compliance using the linear variable differential transducer technique. Enalaprilat-mediated effects were assessed in small and large veins and in the presence and absence of one of two vasoconstrictors: exogenous norepinephrine or physiologic vasoconstriction by cooling. RESULTS: We infused locally in small dorsal hand veins at skin temperatures of less than 29.0 degrees C (baseline distention < 0.35 mm) in the absence of exogenous vasoconstrictors, enalaprilat mediated dose-dependent vasodilation (median effective dose [ED50], 12 ng/min to a maximal effect of 162% +/- 15% of baseline, p < 0.01). Maximal enalaprilat-mediated vasodilation was comparable to dilation mediated by insulin (175% +/-17% of baseline; p = 0.21) and less than dilation mediated by nitroglycerin (221% +/- 20% of baseline; p = 0.011). At skin temperatures > 31 degrees C, enalaprilat mediated dose-dependent vasodilation in small vessels only when vessels were preconstricted with norepinephrine (ED50 = 5.1 ng/min, maximal enalaprilat-mediated effect of 164% +/- 21% of baseline; p < 0.05). CONCLUSIONS: These data suggest enalaprilat mediates local vasodilation in dorsal hand veins, with an ED50 comparable to plasma enalaprilat concentrations achieved with oral enalapril therapy. This effect is dependent on vessel size and on the presence of preconstruction. Local vasodilator effects may be important in the clinical hemodynamic effects of angiotensin converting enzyme inhibitors.     

A two-dimensional simulation of organic transistors

In this paper, we analyze the operation of organic thin-film transistors (TFT's) using two-dimensional (2-B) numerical simulation to: (1) validate the use of simple MOSFET theory to describe the above-threshold behavior; (2) clarify the subthreshold characteristics, and short-channel effects; and (3) illustrate the operation of organic bilayer devices. Our analysis clarifies a number of issues that can help in device design. We also point out differences between the material parameters used in Si-MOSFET and organic FET simulation, and discuss the circumstances under which a semiconductor device simulator can be used for the simulation of organic transistors