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Biomedical subjects

S H Fong

Publications and source records attributed to S H Fong.

4 recordsLinked to original sources
PubMed1999

BWMK1, a novel MAP kinase induced by fungal infection and mechanical wounding in rice.

The activation of the mitogen-activated protein (MAP) kinases by different environmental stresses has been previously observed in several dicot plant species. Here, we report the isolation of a novel MAP kinase in rice that is induced during infection by the blast fungus Magnaporthe grisea or upon mechanical wounding. The gene is designated as BWMK1 for blast- and wound-induced MAP kinase. The cDNA of BWMK1 was isolated from rice leaves challenged by the blast pathogen. Transcripts of the corresponding gene accumulated in rice leaves 4 h after blast inoculation and 30 min after mechanical wounding. This gene encodes a 506 amino acid protein that contains a new dual-phosphorylation activation motif TDY and about 150 unique amino acids on its C terminus. In-gel kinase activity and immunoprecipitation assays confirmed that BWMK1 is a functional MAP kinase. These results show that BWMK1 is a new member of the plant MAP kinase family and may mediate both defense and wound signaling in rice.

Amino Acid Sequence↗
PubMed1997

When is a lower limit of detection low enough?

In cleanup operations and environmental surveillance efforts, a level of concern usually specifies a concentration limit for a particular radionuclide above which some action may be warranted. It is critical that the analytical method selected for measurements has a detection limit well below the action level. This is to guarantee that the technique used provides precise assessment at the level of concern. Sample analysis made with good precision is one of the major steps for obtaining quality data that allow a sound decision on whether the nuclide concentration is in compliance. This paper examines how the magnitude of the detection limit of an analysis method affects the precision of a measurement at the action level. With the established relationship, the detection limit that would achieve a pre-set precision for measurements at a level of concern can be quantitatively determined. The desired detection capability thus serves as a guide for selecting the appropriate measurement system.

Environment↗
PubMed1997

Data quality objectives for surface-soil cleanup operation using in situ gamma spectrometry for concentration measurements.

In situ gamma spectrometry is an efficient method for monitoring the progress of cleanup activities for radioactive contaminants in surface soil and for evaluating the attainment of cleanup standards. However, desired data precision and accuracy must be specified for such a detection system prior to the operation to ensure that the level of uncertainty associated with the concentration measurements is acceptable. A method for developing data quality objectives is described in this paper for in situ gamma spectrometry to achieve numerical goals for data precision and accuracy for cleanup operations. Concentration measurement for a radionuclide at its cleanup level must have a precision commensurate with the importance of cleanup decisions. The 95% lower limit of detection of the system is suggested to be about one tenth the expected system response at the cleanup level. The count time required to achieve the preferred 95% lower limit of detection, and hence the desired precision, can then be determined. The accuracy error arises from the overall calibration factor, which relates the detector responses (e.g., count rate) to physical quantities of interest (e.g., radionuclide soil concentration). The major source of error for the calibration factor using in situ gamma spectrometry is the misidentification of the type of the depth profile of radionuclide concentration in soil. If surrogate radionuclides are used, such as 241Am for plutonium, the variation in the concentration ratio would be another significant source of error. Soil sampling programs performed prior to a cleanup operation will greatly reduce the accuracy error for an in situ detection system, and the analysis of system errors may determine the degree of sampling required. The planning of such a program is discussed in the study. Uncertainty analysis using a Latin Hypercube sampling technique for the calibration factor is also demonstrated. The quantitative result of the uncertainty analysis is useful for determining a nuclide's maximum peak count rate using gamma spectrum that ensures the attainment of the cleanup standard for that nuclide with a pre-specified confidence level (e.g., 95%). The cleanup operation of 239,240Pu in surface soil in the safety shot areas at the Nevada Test Site serves as an example to illustrate the data quality objectives development.

Americium↗