Effect of particle size and spectral sub-range within the UV-VIS-NIR range using diffuse reflectance spectra on multivariate models in evaluating the severity of fusariosis in ground wheat

Control (crops grown in natural conditions) and Fusarium head blight (FHB) damaged (crops inoculated with Fusarium culmorum conidia) grain of four wheat cultivars was ground and sieved into three fractions of different particle size. A series of blended samples differing in content of damaged material were prepared within fractions and cultivars, and diffuse reflectance spectra recorded within the 200–2500 nm wavelength range. Partial least-squares (PLS) models for the percentage of damaged material in blended samples were built for each of twelve series within different spectral ranges, and the root-mean-squared error of cross-validation (RMSECV) was used for the assessment of model performance. Errors using the models were lowest for the finest fraction independent of spectral range; however, their values depended on the cultivar. RMSECV for the finest fraction averaged over cultivars ranged from a little below 3.0 (when the ultraviolet light sub-range was used or participated with another one) to 8.1% (when only the near infrared (NIR) sub-range was used). For the medium and coarse fractions, averaged errors showed the same tendency of dependence on the sub-range(s); however, with higher values that increased with an increase in particle size. In conclusion, within the different fractions of particle size and spectral ranges, the most sensitive to the presence of damaged material were models developed for the finest fraction and when the ultraviolet light sub-range was used in modelling.     

Assessment of Tc-99 monitoring within the western Irish Sea using a numerical model

Water circulation patterns and associated material transport within a highly dynamic system such as the Irish Sea are complex phenomena. Although Tc-99 monitoring programme undertaken by the Radiological Protection Institute of Ireland provides a good insight to the material distribution on the east coast of Ireland, transport patterns within the Irish Sea have not been fully explored. In this study a validated transport model was used to hindcast transport of Tc-99 discharged from the Sellafield plant to determine extents of Tc-99 migration within the Irish Sea and reassess transit times to east coast of Ireland. Transit times are also estimated within a context of changes in meteorological conditions and fluctuations in discharges. Additionally, seasonal and inter-annual circulation patterns were examined.Relationships between discharge times and timing of far field concentrations are highly variable and are dependant on sea dynamics controlling the accumulation and removal of Tc-99 mass. Transport towards the Irish east coast, and consequently transit times, vary intra- and inter-annually, and depend on the prevailing hydrodynamic conditions resulting from meteorological conditions. The transit times from Sellafield to Balbriggan fall within the wide range of 30-240 days; with summer releases resulting in the shortest transit times. The model also indicated a strong relationship between summer concentration peaks on the east coast of Ireland and the strength of the Western Irish Gyre. Sudden increases of Tc-99 concentrations at Balbriggan coincide with peak of sea surface temperatures when the gyre is strongest and when advection is fastest.The adequacy of the current radionuclide monitoring programme within the western Irish Sea is evaluated, and recommendations are made for the development of a more optimised monitoring programme.     

The role of single-stranded DNA in Flp-mediated strand exchange

The Flp recognition target site contains two inverted 13-base pair (bp) Flp binding sequences that surround an 8-bp core region. Flp recombinase has been shown to carry out strand ligation independently of its ability to execute strand cleavage. Using a synthetic activated DNA substrate bearing a 3'-phosphotyrosine group, we have developed an assay to measure strand exchange by Flp proteins. We have shown that wild-type Flp protein was able to catalyze strand exchange using DNA substrates containing 8-bp duplex core sequences. Mutant Flp proteins that are defective in either DNA bending or DNA cleavage were also impaired in their abilities to carry out strand exchange. The inability of these mutant proteins to execute strand exchange could be overcome by providing a DNA substrate containing a single-stranded core sequence. This single-stranded core sequence could be as small as 3 nucleotides. Full activity of mutant Flp proteins in strand exchange was observed when both partner DNAs contained an 8-nucleotide single-stranded core region. Using suicide substrates, we showed that single-stranded DNA is also important for strand exchange reactions where Flp-mediated strand cleavage is required. These results suggest that the ability of Flp to induce DNA bending and strand cleavage may be crucial for strand exchange. We propose that both DNA bending and strand cleavage may be required to separate the strands of the core region and that single-stranded DNA in the core region might be an intermediate in Flp-mediated DNA recombination.     

The major mitomycin C-DNA monoadduct is cytotoxic but not mutagenic in Escherichia coli

BACKGROUND: This study was designed to describe the longitudinal changes in the casein and whey fractions and the total and nonprotein nitrogen contents of preterm human milk for the first 10 days postpartum. METHODS: Eleven mothers delivering at 30 to 34 weeks of gestation were studied, six throughout the first 10 days and five on the first postpartum day. Four milk samples were collected every day by expression of one breast with an electric breast pump. Casein and whey protein were separated from the defatted milk by isoelectric precipitation in calcium chloride and by subsequent ultracentrifugation. The milk nitrogen content was determined before and after acid precipitation. Whey protein and casein were characterized by electrophoresis in polyacrylamide gel. RESULTS: Total and protein nitrogen showed a sharp decrease during the first 3 postpartum days, whereas the nonprotein nitrogen did not change markedly (mean concentration, 0.58 mg.ml-1). Casein content expressed as nitrogen in preterm human milk was 0.35 mg.ml-1 between days 3 and 5 and 0.60 mg.ml-1 between days 6 and 10. The whey protein-casein ratio before day 2, was 100:0, at day 3, 86:14, at day 5, 76:24, and at day 10, 70:30. Three days after delivery, casein levels rose progressively, increasing markedly after day 6. CONCLUSIONS: These findings suggest that delivering before term affects neither casein production nor its chemical characteristics.     

On the cut-off value of negative triaxiality for fracture

Although yield condition of metals does not strongly depend on it, mean stress plays an important role in fracture of metals. A cut-off value of the stress triaxiality equal to −1/3, below which fracture never occurs, was derived analytically from the fracture locus in the principal strain space experimentally reported from upsetting tests. It was found that this result is consistent with tensile tests under hydrostatic pressure (Bridgman tests). Numerical simulations performed in this study with the cut-off value in fracture loci successfully captured the main features observed in tensile tests under hydrostatic pressure by Bridgman and others, and simulated the tests on 1045 steel performed by Kao et al.     

Blackfin处理器在工业图像处理中的应用

随着嵌入式媒体处理器性能的提高,取代许多工业图像处理应用中基于个人计算机(PC)的系统正在成为一种趋势.由于这些处理器能提供低成本、小尺寸、可扩展的图像处理系统,所以它们比功耗和价格较高的其它同类PC系统更具吸引力.     

Upper bound for the number of degrees of freedom for magneto-micropolar flows and turbulence

We present an explicit bound for the number of degrees of freedom for attractor for an incompressible, electrically conducting micropolar fluid flow in the presence of an arbitrary magnetic field. Then we use it to explain the possible mechanism of maintenance of turbulence that is different from that in N-S flows.     

LTCC Microfluidic System

A simple and inexpensive low-temperature cofired ceramic (LTCC) microfluidic device with integrated optical fibers is designed, manufactured, and tested with positive results. Fluidic channels, mixer, detector, optical fiber, light source, light detector, heater, and temperature sensor are integrated in one LTCC module. The optical system in the LTCC microsystem permits measurements of light transmittance and fluorescence. The design, technology, and results of the module's evaluation are presented.     

The shared expertise model for teaching interactive design assistants

The growing complexity of contemporary engineering designs requires the use of sophisticated computer-based design tools. Such tools increase productivity in drafting, configuration and calculations. However, the current generation of design tools plays a rather passive role in the entire design process. Recent progress in knowledge-based engineering design, machine learning and knowledge acquisition allows the development of knowledge-based design assistants which could behave as active partners to human designers, rather than as passive graphical or computational tools. This paper presents the shared expertise model (SEM) of interaction between a human designer and a knowledge-based design assistant, in which the design assistant behaves as an apprentice and a collaborator in the design process. The human designer and his computer-based assistant create designs together, with the assistant proposing routine or even innovative designs, and the human designer correcting and finalizing these design, as well as specifying creative designs. In this process, the assistant also learns from the human designer, constantly extending and improving its knowledge base, and becoming a better design assistant. This is achieved by employing apprenticeship multistrategy learning based on a plausible version space representation. Within the SEM framework, a human designer with limited programming capabilities can directly develop and maintain a personalized knowledge-based design assistant. The use of SEM leads to increased capabilities of the expert-assistant design team. In this paper, some of the main features of the SEM model, as well as its implementation with the Disciple toolkit, are illustrated within the domain of computer workstation configuration.