Decomposition of Gaseous Acetone in an Annular Photoreactor Coated with TiO2 Thin Film

Photocatalytic decomposition of gaseous acetone was studied with a fixed-bed annular reactor using TiO₂ as the photocatalyst. The relation of UV light intensity to the reaction rate was found to be roughly first-ordered. The decomposition of acetone was obviously enhanced with increasing retention time. Removal of acetone was slightly increased with the relative humidity for experiments conducted with relative humidity below 20%. However, the removal of acetone was decreased drastically with relative humidity for experiments conducted with relative humidity greater than 20%. Decomposition of acetone was promoted considerably with increasing oxygen concentration for experiments conducted with oxygen less than 200,000 ppmv, yet the decomposition of acetone was kept relatively constant for experiments conducted with oxygen above 200,000 ppmv. Based on the mass balance for carbon species, the amount of organic intermediates formed for experiments conducted under various conditions were found to be minimal. Experimental results for the decomposition of gaseous acetone by UV/TiO₂ process can be adequately described by the developed two-site Langmuir–Hinshelwood (L–H) kinetic model.     

Non-polar macroreticular resin to recover phenolic acids from a subtropical latosol

A technique has been developed to extract soil phenolics by their adsorption onto resin, the separation of resin from soil, and desorption from the resin followed by high performance liquid chromatography (HPLC) analysis. Four representative phenolic acids, p-hydroxybenzoic, p-hydroxycinnamic, p-methoxybenzoic and 2,4-dimethoxybenzoic acids, were added to a subtropical soil (66 nmol g^?1 soil) and recovered by extraction with Amberlite XAD-4 resin. The recovery efficiency of the added phenolics was greater using a flotation method to separate resin from soil than by a filtration method. The recoveries of p-hydroxybenzoic acid and p-hydroxycinnamic acid decreased with increasing extractant pH. Recoveries of p-methoxybenzoic acid and 2,4-dimethoxybenzoic acid increased slightly with increasing pH. The addition of NaCl to the XAD-4 resin extractant generally increased the recovery of phenolics by filtration but not by flotation. The recoveries of phenolics from the soil by extraction with XAD-4 resin were much greater than by alkaline extraction at pH 11.     

Significance of vitamin E supplementation, dietary content of polyunsaturated fatty acids, and preslaughter stress on oxidative status in pig as reflected in cell integrity and antioxidative enzyme activities in porcine muscle

The present study investigates the combined effects of feed-induced increase in polyunsaturated fatty acids (PUFA) content and/or alpha-tocopherol content in pig muscles and preslaughter stress on cell integrity. Cell integrity was determined by plasma lactate dehydrogenase (LDH) activity, and antioxidative status of muscle was measured by activities of the antioxidative enzymes catalase, superoxide dismutase, and glutathione peroxidase. Preslaughter stress increased LDH activity, reflecting loss in cell membrane integrity independent of increased content of PUFA and/or alpha-tocopherol. However, feed-induced increase of PUFA decreased the LDH activity in plasma immediately after slaughter. Catalase activity in the muscle tissue increased as a consequence of the high-PUFA diet, which may indicate an increased demand caused by introduction of oxidative labile PUFA.     

台湾土石流研究综述

 台湾地狭人稠,平地开发趋于饱和。随着社会经济快速发展,使得山坡地陆续开发,破坏原有之水土保持,且台湾岛之山脉地质大多属沉积岩及变质岩,性质脆弱且易断裂,再加上年平均雨量高达2500mm,其中78%的降雨集中于5—10月的台风季节,因此台湾地区土石流频繁。为了解台湾地区土石流之研究沿革,搜集相关土石流之研究成果,并配合台湾地区重大灾害,分析土石流特性、土石流成分分析、危险评估与重建、抑制工程及现场调查仿真等方面的研究进展。     

Measurement of Atmospheric Formaldehyde and Monoaromatic Hydrocarbons using Differential Optical Absorption Spectroscopy during Winter and Summer Intensive Periods in Seoul, Korea

Ozone effects on Mediterranean forests were studied for 10 years in southern France. The aim of these studies was to understand the impact of the pollutant on foliar damage among Aleppo pine (Pinus halepensis Mill) and Arolla pine (Pinus cembra L) populations. During the summers of 2001 and 2002, ozone concentrations were measured using UV absorption analysers (4) and passive samplers (29) at two forest monitoring sites: Site 1 in the Nice coastal area for Aleppo pine and Site 2 in the Mercantour mountains for Arolla pine, in the vicinity of tree observation sites. AOT 40 values were quite high (25–33 ppm.h), especially in the Mercantour mountains, for the 5 months of measurement. Foliar damage (defoliation and discoloration) and specific symptoms (chlorotic mottle) were observed on 8 Aleppo pine and 13 Arolla pine plots. For Arolla pines, there was a significant correlation between defoliation and chlorotic mottles. There was also a correlation between mean ozone concentrations measured by passive samplers and chlorotic mottles. These correlations were less significant for Aleppo pine.     

Supercritical fluid extraction of 2,4,6-trichloroanisole from cork stoppers

2,4,6-Trichloroanisole (TCA) is the compound most often associated with cork taint in wines and has been shown to have a very low sensory threshold ( approximately 5 ng/L in wine). A supercritical fluid extraction (SFE) method for TCA in bark cork stoppers was developed with quantification via gas chromatography-mass spectrometry with selected ion monitoring. Supercritical carbon dioxide functioned as the extracting solvent, and temperature and pressure were optimized for the extraction. The method was validated using the stable isotope (2)H(5)-TCA as the internal standard. Recovery of TCA from spiked corks was found to be within 1-4% of the theoretical concentration with a coefficient of variation ranging from 2.6 to 9.7%. TCA levels in corks pulled from wines described as tainted by experienced judges ranged from 0.13 to 2.11 microg/g of cork. The SFE procedure offers a rapid, quantitative, nearly solvent-free, and automated method for the extraction of TCA from complex solid matrices such as cork.     

Major phenolics in apple and their contribution to the total antioxidant capacity

The contribution of each phytochemical to the total antioxidant capacity of apples was determined. Major phenolic phytochemicals of six apple cultivars were identified and quantified, and their contributions to total antioxidant activity of apples were determined using a 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging assay and expressed as vitamin C equivalent antioxidant capacity (VCEAC). Average concentrations of major phenolics and vitamin C in six apple cultivars were as follows (mg/100 g of fresh weight of apples): quercetin glycosides, 13.20; procyanidin B(2), 9.35; chlorogenic acid, 9.02; epicatechin, 8.65; phloretin glycosides, 5.59; vitamin C, 12.80. A highly linear relationship (r (2) > 0.97) was attained between concentrations and total antioxidant capacity of phenolics and vitamin C. Relative VCEAC values of these compounds were in the order quercetin (3.06) > epicatechin (2.67) > procyanidin B(2) (2.36) > phloretin (1.63) > vitamin C (1.00) > chlorogenic acid (0.97). Therefore, the estimated contribution of major phenolics and vitamin C to the total antioxidant capacity of 100 g of fresh apples is as follows: quercetin (40.39 VCEAC) > epicatechin (23.10) > procyanidin B(2) (22.07) > vitamin C (12.80) > phloretin (9.11) > chlorogenic acid (8.75). These results indicate that flavonoids such as quercetin, epicatechin, and procyanidin B(2) rather than vitamin C contribute significantly to the total antioxidant activity of apples.     

Significance of preslaughter stress and different tissue PUFA levels on the oxidative status and stability of porcine muscle and meat

Polyunsaturated fatty acids (PUFAs) and exercise-induced stress are known to increase the oxidative susceptibility of lipids in muscle tissue. In contrast, antioxidative enzymes, e.g., catalase, superoxide dismutase, and glutathione peroxidase, are known to help sustain the delicate oxidative balance in biological tissue upon the application of stressors. The present study investigates the combined effect of different diet-induced muscle PUFA contents and preslaughter stress on the activity of antioxidative muscle enzymes and the oxidative stability of cooked meat. An increased content of unsaturated fatty acids in the tissue led to a decreased activity of lactate dehydrogenase in the plasma, indicating increased cell integrity. Catalase activity in the muscle tissue increased with increasing PUFA levels. However, this upregulation in antioxidative status of the muscle could not counteract the subsequent development of accelerated lipid oxidation in cooked meat as measured in terms of thiobarbituric acid reactive substances. Moreover, preslaughter stress induced increasing oxidative changes with elevated PUFA levels in the muscle tissue.     

Rapid determination of color additives, using the C18 cartridge

A reliable method has been developed for the rapid separation and identification of the 7 permitted FD&C dyes (Red Nos. 3 and 40; Blue Nos. 1 and 2; Yellow Nos. 5 and 6; Green No. 3) and the recently banned FD&C Red No. 2 in foods. The colors are separated by using the C18 cartridge, and their identity is confirmed by spectrophotometry.