The Current State of Solar Modeling

Data from the Global Oscillation Network Group (GONG) project and other helioseismic experiments provide a test for models of stellar interiors and for the thermodynamic and radiative properties, on which the models depend, of matter under the extreme conditions found in the sun. Current models are in agreement with the helioseismic inferences, which suggests, for example, that the disagreement between the predicted and observed fluxes of neutrinos from the sun is not caused by errors in the models. However, the GONG data reveal subtle errors in the models, such as an excess in sound speed just beneath the convection zone. These discrepancies indicate effects that have so far not been correctly accounted for; for example, it is plausible that the sound-speed differences reflect weak mixing in stellar interiors, of potential importance to the overall evolution of stars and ultimately to estimates of the age of the galaxy based on stellar evolution calculations.     

Antioxidant properties of Fusarium head blight-resistant and -susceptible soft red winter wheat grains grown in Virginia

Fusarium head blight (FHB) has emerged as a major threat to wheat crops around the world, and it has been hypothesized that wheat antioxidants may play a role against Fusarium infections. The current study aimed to determine antioxidant properties of FHB-resistant wheat grains as compared to susceptible wheat. The wheat samples were collected from a single growing location (Warsaw, VA) and the same growing season. The results showed that both FHB-resistant and -susceptible wheat grains exerted strong radical scavenging activities against DPPH* radical [0.91-1.53 micromol of Trolox equivalents (TE)/g], peroxyl radical (15.5-24.5 micromol of TE/g), and hydroxyl radical (15.7-35.8 micromol of TE/g). Their total phenolic contents ranged from 888 to 1117 microg of gallic acid equivalents (GAE)/g. Five phenolic acids including ferulic, syringic, vanillic, caffeic, and p-coumaric acids were determined in soluble and insoluble fractions of wheat grains, altogether with a range of 219-389 microg/g. On average, the FHB-resistant wheat group showed significantly higher average values in DPPH* and hydroxyl radicals scavenging activities (30 and 41% higher, respectively) than the FHB-susceptible wheat group.     

In vitro Effect of Zearalenone and α-Zearalenol on Boar Sperm Characteristics and Acrosome Reaction

This study was conducted to determine the in vitro effects of three different concentrations (125, 187.5 and 250 microM in diluted semen) of zearalenone (zen) and alpha-zearalenol (alpha-zen) on boar sperm. Semen parameters such as motility, viability and spontaneous acrosome reaction were evaluated. From the results it was shown that both zen and alpha-zen affected the sperm characteristics significantly (p < 0.05), except for alpha-zen at the low concentration which did not decrease the percentage of live reacted spermatozoa significantly. In conclusion, zen and alpha-zen are directly toxic when they affect boar semen in vitro and consequently decrease the fertilization ability of the sperm. The higher the concentration of mycotoxin tested, the greater the decline of sperm parameters noticed. The influence of mycotoxins was found to be time- and dose-dependent.     

Simulated rainfall evaluation of revegetation/mulch erosion control in the Lake Tahoe basin—3: soil treatment effects

Revegetation, or other erosion control treatments of disturbed soil slopes in forested areas and along highways of the Lake Tahoe basin are directed at reduction of sediment loading to waterways reaching the lake. However, following treatment, little vegetation monitoring, or hydrologic evaluation has been conducted either to determine if the various treatments are successful or to assess the duration of erosion control anticipated in the field. Here, we build upon results from use of the portable rainfall simulator (RS) described in the first two papers of this series to evaluate cover and revegetation treatment effects on runoff rates and sediment concentrations and yields from disturbed granitic and volcanic soils in the basin. The effects of slope on rainfall runoff, infiltration and erosion rates were determined at several revegetated road cut and ski run sites. Rainfall simulation (∼60 mm h⁻¹, approximating a 100‐year, 15‐minute storm) had a mean drop size of ∼2·1 mm and approximately 70 per cent of ‘natural’ rainfall kinetic energy. Measurements of: time to runoff; infiltration; runoff amount; sediment yield; and average sediment concentration were obtained. Runoff sediment concentrations and yields from sparsely covered volcanic and bare granitic soils can be correlated to slope. Sediment concentrations and yields from nearly bare volcanic soils exceeded those from granitic soils by an order of magnitude across slopes ranging from 30–70 per cent. Revegetation, or application of pine‐needle mulch covers to both soil types dramatically decreased sediment concentrations and yields. Incorporation of woodchips or soil rehabilitation that includes tillage, use of amendments (biosol, compost) and mulch covers together with plant seeding resulted in little or no runoff or sediment yield from both soils. Repeated measurements of sediment concentrations and yields in the subsequent two years following woodchip or soil rehabilitation treatments continued to result in little or no runoff. Revegetation treatments involving only use of grasses to cover the soils were largely ineffective due to sparse sustainable coverage (< 35 per cent) and inadequate infiltration rates. Copyright © 2005 John Wiley & Sons, Ltd.     

Cubic AgPb(m)SbTe(2+m): bulk thermoelectric materials with high figure of merit

The conversion of heat to electricity by thermoelectric devices may play a key role in the future for energy production and utilization. However, in order to meet that role, more efficient thermoelectric materials are needed that are suitable for high-temperature applications. We show that the material system AgPb(m)SbTe(2+m) may be suitable for this purpose. With m = 10 and 18 and doped appropriately, n-type semiconductors can be produced that exhibit a high thermoelectric figure of merit material ZTmax of approximately 2.2 at 800 kelvin. In the temperature range 600 to 900 kelvin, the AgPb(m)SbTe(2+m) material is expected to outperform all reported bulk thermoelectrics, thereby earmarking it as a material system for potential use in efficient thermoelectric power generation from heat sources.     

Development and validation of a food-frequency questionnaire for the determination of detailed fatty acid intakes

OBJECTIVE: To validate a fat intake questionnaire (FIQ) developed to assess habitual dietary intake while focusing on the assessment of detailed fatty acid intake including total trans unsaturated fatty acids (TUFA). DESIGN: An 88 food item/food group FIQ was developed using a meal pattern technique. Validation was achieved by comparison with dietary intake assessed by a modified diet history (DH) in a cross-over design. Eighty-four individuals supplied adipose tissue biopsies for linoleic acid and total TUFA analysis as an independent validation of the FIQ and DH. SETTING: Medical Centre, Dublin Airport, Republic of Ireland. SUBJECTS: One hundred and five healthy volunteers (43 females and 62 males aged 23-63 years). RESULTS: Significant correlations (P<0.0005) were achieved for intakes of energy (0.78), total fat (0.77), saturated fat (0.77), monounsaturated fat (0.63), polyunsaturated fat (0.73), TUFA (0.67) and linoleic acid (0.71) assessed by the FIQ compared with the DH. Linoleic acid intake assessed by the FIQ and the DH was significantly correlated with adipose tissue concentrations (r=0.58 and 0.49, respectively; P<0.005); however, total TUFA intake was poorly correlated with adipose tissue concentrations (r=0.17 and 0.10 for FIQ and DH, respectively). CONCLUSIONS: The FIQ compared favourably with the DH in assessing habitual diet, in particular fatty acid intake. In addition, the FIQ was successfully validated against the linoleic acid composition of adipose tissue, an independent biomarker of relative fatty acid status. The FIQ could therefore be used as an alternative to the DH as it is a shorter, less labour-intensive method.     

Transgenic expression of bean alpha-amylase inhibitor in peas results in altered structure and immunogenicity

The development of modern gene technologies allows for the expression of recombinant proteins in non-native hosts. Diversity in translational and post-translational modification pathways between species could potentially lead to discrete changes in the molecular architecture of the expressed protein and subsequent cellular function and antigenicity. Here, we show that transgenic expression of a plant protein (alpha-amylase inhibitor-1 from the common bean (Phaseolus vulgaris L. cv. Tendergreen)) in a non-native host (transgenic pea (Pisum sativum L.)) led to the synthesis of a structurally modified form of this inhibitor. Employing models of inflammation, we demonstrated in mice that consumption of the modified alphaAI and not the native form predisposed to antigen-specific CD4+ Th2-type inflammation. Furthermore, consumption of the modified alphaAI concurrently with other heterogeneous proteins promoted immunological cross priming, which then elicited specific immunoreactivity of these proteins. Thus, transgenic expression of non-native proteins in plants may lead to the synthesis of structural variants possessing altered immunogenicity.