Distinguishing enzymes using metabolome data for the hybrid dynamic/static method-0

<p><b>Copyright information:</b></p><p>Taken from "Distinguishing enzymes using metabolome data for the hybrid dynamic/static method"</p><p>http://www.tbiomed.com/content/4/1/19</p><p>Theoretical Biology & Medical Modelling 2007;4():19-19.</p><p>Published online 20 May 2007</p><p>PMCID:PMC1892778.</p><p></p>s after subtraction of the basal error (MRE shown in Table 1). Numbers next to the symbols represent weighting coefficients

Enhancement of Mass Interception Coefficient Data of Radiostrontium by Leafy Crops Using Global Fallout ⁹⁰Sr and Naturally Occurring ⁷Be

When artificial radionuclides are released into the atmospheric environment, one of the important processes by which they affect the human radiation dose is the direct deposition of the radionuclides onto crop surfaces. Because leafy vegetables are consumed while fresh and often raw, the mass interception coefficient [= concentration in food (Bq/kg dry mass (DM) or fresh mass)/total deposition (Bq/m2)] is a key parameter for estimating radionuclide concentrations in crops after the deposition of radionuclides on plant stands. However, such data are still sparse, especially for radiostrontium (89Sr and 90Sr). To enhance the mass interception coefficient data for leafy crops, we used global fallout 90Sr data in leafy crops harvested in 1963–1965 and the deposition data for the corresponding crop growing period. Geometric mean values of the mass interception coefficient of 90Sr for leafy crops were 2.8 m2 kg–1 DM for spinach, 0.60 m2 kg–1 DM for cabbage, and 1.3 m2 kg–1 DM for Chinese cabbage. For comparison, we measured naturally occurring 7Be in giant butterbur leaves, and the results showed that the data were similar to those of 90Sr for spinach. These data were similar to the previously obtained data by single spike radiotracer experiments. Therefore, in the case of nuclear emergency situations, mass interception coefficient data obtained using global fallout 90Sr and/or naturally occurring 7Be should be valuable to estimate radioactivity contamination levels of radiostrontium directly deposited on leafy crops

Estimation of Te-132 Distribution in Fukushima Prefecture at the Early Stage of the Fukushima Daiichi Nuclear Power Plant Reactor Failures

Tellurium-132 (¹³²Te, half-life: 3.2 d) has been assessed as the radionuclide with the third largest release from the Fukushima Daiichi Nuclear Power Plant (FDNPP) in March 2011; thus it would have made some dose contribution during the early stage of the reactor failures. The available data for ¹³²Te are, however, limited. In this study, available reported values of other isotopes of Te were compiled to estimate ¹³²Te concentration (in MBq m^–2). It was found that ¹³²Te and ^129mTe (half-life: 33.6 d) concentrations were well correlated (<i>R</i> = 0.99, <i>p</i> < 0.001) by <i>t</i> test. Thus, ¹³²Te concentrations on March 11, 2011 were estimated from ^129mTe using the concentration conversion factor (¹³²Te /^129mTe) of 14.5. It was also found that since deposited ^129mTe was well retained in the soil, the data collected in March–May of 2011 were applicable to ¹³²Te estimation. It was possible to obtain the first ¹³²Te concentration contour map for the eastern part of Fukushima Prefecture, including data from within the 20-km exclusion zone around the FDNPP, using these newly available estimated ¹³²Te data sets

Determination of ¹³⁵Cs and ¹³⁵Cs/¹³⁷Cs Atomic Ratio in Environmental Samples by Combining Ammonium Molybdophosphate (AMP)-Selective Cs Adsorption and Ion-Exchange Chromatographic Separation to Triple-Quadrupole Inductively Coupled Plasma–Mass Spectrometry

Since the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in 2011, the activity ratio of ¹³⁴Cs/¹³⁷Cs has been widely used as a tracer for contamination source identification. However, because of the short half-life of ¹³⁴Cs (2.06 y), this tracer will become unavailable in the near future. This article presents an analytical method for the determination of the long-lived ¹³⁵Cs (<i>t</i>_2/1 = 2 × 10⁶ y) and the atomic ratio of ¹³⁵Cs/¹³⁷Cs, as a promising geochemical tracer, in environmental samples. The analytical method involves ammonium molybdophosphate (AMP)-selective adsorption of Cs and subsequent two-stage ion-exchange chromatographic separation, followed by detection of isolated radiocesium isotopes via triple-quadrupole inductively coupled plasma–mass spectrometry (ICP-MS/MS). The AMP-selective adsorption of Cs and the chromatographic separation system showed high decontamination factors (10⁴–10⁵) for interfering elements, such as Ba, Mo, Sb, and Sn. Using ICP-MS/MS, only selected ions enter the collision/reaction cell to react with N₂O, reducing the isobaric interferences (¹³⁵Ba⁺ and ¹³⁷Ba⁺) and polyatomic interferences (⁹⁵ Mo⁴⁰Ar⁺, ⁹⁷ Mo⁴⁰Ar⁺, ¹¹⁹Sn¹⁶O⁺, and ¹²¹Sb¹⁶O⁺) produced by sample matrix ions. The high abundance sensitivity (10^–9 for the ¹³⁵Cs/¹³³Cs ratio) provided by ICP-MS/MS allowed reliable analysis of ¹³⁵Cs and ¹³⁷Cs isotopes with the lowest detection limits ever reported by mass counting methods (0.01 pg mL^–1 and 0.006 pg mL^–1, respectively). The developed analytical method was successfully applied to the determination of ¹³⁵Cs and ¹³⁷Cs isotopes in environmental samples (soil, litter, and lichen) collected after the FDNPP accident for contamination source identification