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271.
Jack Demarest 《Zoo biology》1988,7(4):387-391
272.
A new formula for the statistical uncertainty of “loss-free counting” (LFC) is presented. Its validity is demonstrated by
comparing with experimental data obtained with a HPGe γ-ray spectrometer. Also, computer simulation data of nuclear counting
with different types of count loss (pileup rejection, extending and nonextending dead time) are in agreement with the predicted
counting uncertainty. The proposed formula for LFC uncertainty is applicable to spectrometers with a classical semi-Gaussian
pulse-shaping amplifier as well as with a gated-integrator amplifier. Hence, achieving statistical control seems to be a feasible
goal. 相似文献
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275.
Kris Gevaert Hans De Mol Jean-Luc Verschelde Jozef Van Damme Stefaan De Boeck Joël Vandekerckhove 《Journal of Protein Chemistry》1997,16(5):335-342
A combination of techniques is presented allowing gel-purified protein identification in the femtomole range using matrix-assisted-laser-desorption-ionization mass spectrometry. The proteins are detected in the primary gel by a sensitive negative staining procedure, transferred, and concentrated in a secondary gel matrix. There, they are digested in the presence of H2
18O and their sequences are predicted (1) by peptide mass fingerprinting, (2) by comparing the post-source-decay (PSD) spectra with theoretical spectra of candidate isobaric peptides using a computer algorithm called MassFrag, and (3) by a manual readout of the 18O/16O-labeled fragmentation ions in the PSD spectra. 相似文献
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277.
Isabelle Sioen John Van Camp Frederik A. M. Verdonck Nicky Van Thuyne Jan L. Willems Stefaan W. J. De Henauw 《人类与生态风险评估》2007,13(3):632-657
Seafood consumption is related to both favorable health benefits of nutrients and to potential adverse health impacts of chemical contamination. To quantify the magnitude of this dilemma, probabilistic intake assessments can be performed. One step in such a procedure involves the determination of nutrient and contaminant concentrations in seafood for which data need to be collected. This article describes the process of building up a database containing previously published contaminant concentrations in seafood, and defining input distributions characterizing the variability. During the constitution of the database, several problems influencing the comparability of the data were encountered related to (1) sampling plans of the published data; (2) sample handling prior to analysis; (3) analytical methodologies; (4) the format of reporting results; and (5) missing data. Different solutions for these methodological problems have been developed. Contaminant concentrations ranges per gram fresh weight of 2.4–4390.0 ng for mercury, 0.1–5736.6 ng for the sum of indicator PCB, 0.002–115.000 pg TEQ for the sum of all PCBs, 0.002–34.400 pg TEQ for dioxins, and 0.006–126.000 pg TEQ for total of dioxin-like compounds were found. This work confirms that more guidelines are needed to standardize the analytical methodologies to be used and the format for result reporting in order to improve the comparability of data critical to conduct a human intake and risk-benefit assessment. 相似文献
278.
Lubing Zhou Joseph W. Gunnet Mike Moore Ellen V. Cryan Jun Z. Xu Keith T. Demarest 《Biotechnology letters》2001,23(24):2067-2073
In our search for a cell line expressing endogenous human motilin receptor, we have discovered that theTE671 cell line, a neuron-derived medulloblastoma human line, expresses functional motilin receptors. The cDNA of the receptor was isolated from the cells and its sequence was confirmed to be identical to the previously reported cDNA sequence isolated from human thyroid. The function of the receptor protein was evaluated both for its ability to inhibit the binding of 125I-motilin to a crude membrane preparation of TE671 cells and for activation of the phospholipase C signal transduction pathway by calcium mobilization assay. The precise numbers of motilin receptor RNA molecule in TE671 cell and 24 human tissues were quantitatively determined by real-time PCR. TE671 cell line should be a useful tool for the study of motilin receptor-involved signal transduction in humans. 相似文献
279.