Browsing by Author "Li, CW"

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beta-Lactoglobulin is a sensitive thermal maker in dry milk as identified by monoclonal antibody approach
(2003-03-17)
Chen, WL
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Huang, MT
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Liu, HC
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Li, CW
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Mao, SJT
Distinction between dry and raw milk using monoclonal antibodies prepared against dry milk proteins
(2004-08-01)
Chen, WL
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Huang, MT
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Liu, HC
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Li, CW
;
Mao, SJT
It is well established that the heating process during the preparation of dry milk (DMLK) causes structural changes in some milk proteins. However, because such changes are subtle, whether they can be detected by an immunochemical approach remains questionable. The present study attempted to develop a sensitive mAb that might distinguish the DMLK from freshly prepared raw milk. To test this possibility, we immunized mice with commercially prepared DMLK and produced a panel of mAb. From 900 hybridomas screened using an ELISA, 4 clones were found to be specific to DMLK; the other 68 clones recognized both DMLK and raw milk. In contrast to polyclonal antibodies, only the specific mAb could detect the DMLK spiked into the raw milk at as low as 5% in concentration (vol/vol). Western blot analysis shows that these specific mAb were all directed against beta-lactoglobulin (LG) and LG-milk protein conjugates. These mAb reacted with raw milk heated at 95 for 15 min; the reaction with LG-conjugates, however, was abolished when treated with reducing reagent. Thus, results suggests that a new antigenic epitope was exposed in a heating process, and the thio group of LG cross linked with other protein moiety played a provocative role in mAb recognition. A hypothetical model with respect to the interaction between the mAb and DMLK is proposed and discussed.
The numerical range of a nonnegative matrix
(2002-07-15)
Li, CW
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Tam, BS
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Wu, PY
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應用數學系
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Department of Applied Mathematics
We offers an almost self-contained development of Perron-Frobenius type results for the numerical range of an (irreducible) nonnegative matrix, rederiving and completing the previous work of Issos, Nylen and Tam, and Tam. and Yang on this topic. We solve the open problem of characterizing nonnegative matrices whose numerical ranges are re gular convex polygons with center at the origin. Some related results are obtained and some open problems are also posed. (C) 2002 Elsevier Science Inc. All rights reserved.
Thermal denaturation of beta-lactoglobulin as probed by an monoclomal antibody
(2004-03-23)
Chen, WL
;
Huang, MT
;
Li, CW
;
Liu, HC
;
Mao, SJT