Effects of protein and peptide addition on lipid oxidation in powder model system

The effect of protein and peptide addition on the oxidation of eicosapentaenoic acid ethyl ester (EPE) encapsulated by maltodextrin (MD) was investigated. The encapsulated lipid (powder lipid) was prepared in two steps, i.e., mixing of EPE with MD solutions (+/- protein and peptides) to produce emulsions and freeze-drying of the resultant emulsions. EPE oxidation in MD powder progressed more rapidly in the humid state [relative humidity (RH) = 70%] than in the dry state (RH = 10%). The addition of soy protein, soy peptide, and gelatin peptides improved the oxidation stability of EPE encapsulated by MD, and the inhibition of lipid oxidation by the protein and the peptides was more dramatic in the humid state. Especially, the oxidation of EPE was almost perfectly suppressed when the lipid was encapsulated with MD + soy peptide during storage in the humid state for 7 days. Several physical properties such as the lipid particle size of the emulsions, the fraction of nonencapsulated lipids, scanning electron microscopy images of powder lipids, and the mobility of the MD matrix were investigated to find the modification of encapsulation behavior by the addition of the protein and peptides, but no significant change was observed. On the other hand, the protein and peptides exhibited a strong radical scavenging activity in the powder systems as well as in the solution systems. These results suggest that a chemical mechanism such as radical scavenging ability plays an important role in the suppression of EPE oxidation in MD powder by soy proteins, soy peptides, and gelatin peptides.     

Acidic Precipitation and Large-Scale Transport of Air Pollutants Observed in Korea

Acid rain at a rural site in Chongwon (KHN), central Korea has been under observation since 1990. To substantiate the 10-year observations, rain samples from six other sites were also collected and analyzed. Results show that acid rain occurred frequently at all sites. At KHN, seasonal and annual variability of pH values had a 10-year VWM value of 4.67 and an arithmetic mean value of 5.09. In general, a high value of pH occurred during springtime when the occurrence of yellow sand (dust) was prevalent in East Asia; during summer, heavy rain usually contained neutral pH values. During other seasons, the degree of acidic precipitation usually coincided with certain air flows. Most frequently, air flows and cyclones coming from south and central China often resulted in precipitation with low pH values observed in Korea. Using daily satellite observations from 1996, we have also been monitoring the long-range and large-scale transport of air pollutants (LSTAP) over East Asia. Many samples of LSTAP were obtained when they were crossing the Yellow Sea and moving over the Korean Peninsula and to SW Japan. The width of the Yellow Sea is ca. 350～700 km and air pollutants take 1～2 days to cross it. Cases of acid rain in Korea clearly correlate wth the LSTAP from source regions in China.     

Modelling the Vertical Transport of Pollutants by Fronts

A quantitative study of the amount of air transported between the boundary layer and the free atmosphere is important for understanding air quality and upper tropospheric ozone, which is a greenhouse gas. Frontal systems are known to be an effective mechanism for the vertical transport of pollutants. Numerical experiments have been performed with a simple two-dimensional front model to simulate vertical transport of trace gases within developing cold fronts. Three different trace gases experiments have been done numerically according to the different initial fields of trace gases such as aerosol, ozone and H₂O₂. Trace gas field tilts to the east while the front tilts to the west. Aerosol simulation shows that pollutants can be transported out of the boundary to altitudes of about 10 km. The stratospheric ozone is brought downwards in a tropopause fold behind of the frontal surface. The meridional gradient in trace gas (H₂O₂) can cause a complicate structure in the trace field by the meridional advection.     

Development of an enzyme-linked immunosorbent assay for the pyrethroid cypermethrin

A competitive enzyme-linked immunosorbent assay (ELISA) for the detection of cypermethrin was developed. Two haptens, the trans- and cis-isomers of 3-[(+/-)-cyano-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarbonyloxy]methyl]phenoxyacetic acid, were conjugated with thyroglobulin as immunogens. Four antisera were generated and screened against six different coating antigens. The assay that was the most sensitive for cypermethrin was optimized and characterized. The IC(50) for cypermethrin was 13.5 +/- 4.3 microg/L, and the lower detection limit (LDL) was 1.3 +/- 0.5 microg/L. This ELISA had relatively low cross-reactivities with other major pyrethroids, such as deltamethrin, phenothrin, resmethrin, fluvalinate, and permethrin. Methanol was found to be the best organic cosolvent for this ELISA, with an optimal sensitivity observed at a concentration of 40% (v/v). The assay parameters were unchanged at pH values between 5.0 and 8.0, whereas higher ionic strengths strongly suppressed the absorbances. To increase the sensitivity of the overall method, a C(18) sorbent-based solid-phase extraction was applied to various domestic and environmental water samples. The water samples, fortified with cypermethrin, were analyzed according to this method. Good recoveries and correlation with spike levels were observed.     

Allocation of varietal testing efforts for implementing conifer multi-varietal forestry using white spruce as a model species

• Introduction   

Multi-varietal forestry (MVF) is the deployment of tested tree varieties in plantation forestry. Computer simulation using POPSIM Simulator identified optimal combination of numbers of families, varieties per family and ramets per variety (nf, nc and nr, respectively) yielding the largest genetic gain for a specific status number (NS) in a varietal test (VT) intended for MVF of conifers.     

Ochratoxin A in Korean food commodities: occurrence and safety evaluation

To evaluate the exposure of Koreans to ochratoxin A, we conducted a survey in 2003 for ochratoxin A in various domestic food commodities: 60 polished rices, 22 barleys, 35 wheat flours, 46 beers, and 14 unstrained rice wine (makkolli) samples. They were analyzed for ochratoxin A using immunoaffinity column and high-performance liquid chromatography (HPLC)-fluorescence detection, and the positive samples were confirmed using HPLC-tandem mass spectrometry. By combining results from different surveys on the levels of ochratoxin A in selected foods and the consumption patterns, we obtained the Korean probable daily intakes (PDI) of ochratoxin A. The polished rice commodity had the highest mean levels of ochratoxin A, which ranged from 0.2 (not detected, i.e., ND = 0) to 1.0 ng/g (ND = limit of detection, i.e., LOD). The estimated PDI for all Koreans fell into the range of 0.8-4.1 ng/kg bw/day, while for heavy consumers the estimates ranged from 1.7 to 9.1 ng/kg bw/day, which did not exceed the PTDI value (14 ng/kg bw/day). Staple rice is the major contributor (>90%) to the Korean dietary intake of ochratoxin A. On the basis of these estimates, it may be concluded that there is at present no considerable risk of ochratoxin A exposure for the average Korean consumer.     

High-affinity monoclonal antibodies for detection of the microbial metabolite, 2-methylisoborneol

The production of 2-methylisoborneol (MIB) by certain fungi and algae can contribute musty off-flavors to foods and water supplies if uncontrolled. The goal of this research was to develop a nonsensory simple method for the detection of MIB. Anti-MIB monoclonal antibodies were produced by immunizing mice with borneol-conjugated protein and selecting positive clones with an MIB-protein conjugate. An indirect competitive immunoassay developed using this antibody had a detection limit of 0.6 microg L(-)(1) and an I(50) value of 5 microg L(-)(1). Detection was relatively specific for MIB and showed 20% cross-reactivity with borneol or isoborneol and 4-5% cross-reactivity with camphor. No cross-reactivity to geosmin was observed.     

Formation of bound residues of 8-hydroxybentazon by oxidoreductive catalysts in soil

This study was performed to determine which oxidoreductive catalysts were most efficient in catalyzing the binding of 8-hydroxybentazon to soil humic substances. 8-Hydroxybentazon was completely transformed by an oxidoreductive enzyme, laccase of Myceliophthora thermophila, at pH 3.0-7.0 within 30 min. When abiotic catalysts, manganese(IV), iron(III), and aluminum oxides were used in the same pH range, 8-hydroxybentazon was completely transformed only by manganese(IV) oxide (delta-MnO2), but a relatively small amount of 8-hydroxybentazon was transformed by iron(III) oxide and aluminum oxide. The adsorption of 8-hydroxybentazon in the soil showed an H-type and coincided well with the Langmuir isotherm. To better understand the factors involved in the rapid and strong binding of 8-hydroxybentazon with soil humic substances, 8-hydroxybentazon transformation by oxidoreductive catalysts was studied in various soil conditions: air-dried, preincubated, sterilized, and iron(III) oxide and manganese(IV) oxide free. 8-Hydroxybentazon was completely transformed within 24 h in the decreasing order of preincubated, air-dried, and sterilized soils. However, little transformation was observed in the iron(III) oxide and manganese(IV) oxide free soils. These results suggest that the major catalyst responsible for the rapid and strong binding of 8-hydroxybentazon to soil humic substances is a metal oxide, manganese(IV) oxide, not a soil oxidoreductive enzyme.     

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.     

Factors influencing the occurrence and severity of farm accidents: comparing work-related and nonwork-related events

Economic incentives are emerging as useful preventive approaches to motivating farmers to adopt safer farming and managerial practices. The effectiveness of these programs and incentives will be enhanced by focusing resources on factors that play a critical role in contributing to farm accidents and the injury severity. A primary objective is to identify and assess the relative impact of factors that jointly influence the probability of work-related farm accidents relative to nonwork-related accidents and the severity of farm accidents. The model uses survey data on producer characteristics, farm organization, and work routines from the Georgia Healthy Farmers Project (GHFP). A probit model describing the factors that influence the probability of a work-related accident is estimated jointly with an ordered probit model for farm accident severity. The probit model indicates that older farmers and hired farm workers have higher probabilities of experiencing work-related accidents relative to nonwork-related events. Significant variables that influence the severity of farm accidents are more difficult to identify from the ordered probit models for both work-related and nonwork-related farm accidents.