Browsing by Author "Yang, MC"

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A novel conformation-dependent monoclonal antibody specific to the native structure of beta-lactoglobulin and its application
(2006-03-01)
Chen, WL
;
Liu, WT
;
Yang, MC
;
Hwang, MT
;
Tsao, JH
Molten globules are thought to be general intermediates in protein folding and unfolding. beta-lactoglobulin (beta-LG) is one of the major bovine whey proteins, constituting similar to 10 to 15% of total milk proteins. We have recently identified beta-LG as a superior marker for evaluating thermally processed milk. Strand D of beta-LG participates in irreversible thermal unfolding as probed by a monoclonal antibody (mAb) specific to thermally denatured beta-LG. In the present study, we used native beta-LG as an immunogen to test the hypothesis that a specific mAb against the native beta-LG could be established. As result, a mAb (4H11E8) directed against the native structure of beta-LG was made. The antibody did not recognize the heat-denatured form of beta-LG, such as its dimer and aggregates. Immunoassay using this "native" mAb showed that the stability of beta-LG was at temperatures = 70 degrees C. beta-Lactoglobulin began to deteriorate between 70 and 80 degrees C over time. The denaturation was correlated with the transition temperature of beta-LG. Further chemical modification of Cys (carboxymethylation) or positively charged residues (acetylation) of beta-LG totally abolished its immunoreactivity, confirming the conformation-dependent nature of this mAb. Using competitive ELISA, the 4H11E8 mAb could determine the native beta-LG content in commercially processed milks. Concentrations of native beta-LG varied significantly among the local brands tested. From a technological standpoint, the mAb prepared in this study is relevant to the design and operation of appropriate processes for thermal sanitation of milk and of other dairy products.
Cycles in highly faulty hypercubes
(2005)
Yang, MC
;
Tan, JJM
;
Hsu, LH
;
資訊工程學系
;
Department of Computer Science
The hypercube Q(n) is one of the most popular networks. In, this paper, we first prove that the n-dimensional hypercube is 2n - 5 conditional fault- bipancyclic. That is, an injured hypercube with up to 2n - 5 faulty links has a cycle of length I for every even 4 <= l <= 2(n) when each node of the hypercube is incident with at least two healthy links. In addition, if a certain node is incident with less than two healthy links, we show that an injured hypercube contains cycles of all even lengths except hamiltonian cycles with up to 2n - 3 faulty links. Furthermore, the above two results are optimal. In conclusion, we find cycles of all possible lengths in injured hypercubes with up to 2n - 5 faulty links under all possible fault distributions.
Epitope mapping of a monoclonal antibody specific to bovine dry milk - Involvement of residues 66-76 of strand D in thermal denatured beta-lactoglobulin
(2005-02-04)
Song, CY
;
Chen, WL
;
Yang, MC
;
Huang, JP
;
Mao, SJT
beta-Lactoglobulin (beta-LG) is a bovine milk protein sensitive to thermal denaturation. Previously, we demonstrated that such structural change can be detected by a monoclonal antibody (mAb) specific to denatured beta-LG. In the present study, we show a dramatic increase in beta-LG immunoreactivity when heating raw milk between 70 and 80 degreesC. To map out the specific epitope of beta-LG recognized by this mAb, we used a combined strategy including tryptic and CNBr fragments, chemical modifications (acetylation and carboxymethylation), peptide array containing in situ synthesized peptides, and a synthetic soluble peptide for immunoassays. The antigenic determinant we defined was exactly located within the D strand (residues 66-76) of beta-LG. Circular dichroic spectral analysis shows that carboxymethylation on beta-LG not only resulted in a substantial loss of beta-configuration but also exerted a 10 times increase in immunoreactivity as compared with heated beta-LG. The result suggests that a further disordered structure occurred in beta-LG and thus rendered the mAb recognition. Mutations on each charged residue (three Lys and one Glu) revealed that Lys-69 and Glu-74 were extremely essential in maintaining the antigenic structure. We also show an inverse relationship between the immunoreactivity in heated beta-LG and its binding to retinol or palmitic acid. Most interestingly, pH 9-10, which neutralizes the Lys groups of beta-LG, not only reduced its immunoreactivity but also its binding to palmitic acid implicating a role of Lys-69. Taken together, we concluded that strand D of beta-LG participated in the thermal denaturation between 70 and 80 degreesC and the binding to retinol and palmitic acid. The antigenic and biochemical roles of mAb specific to D strand are discussed in detail.
Fault-tolerant cycle-embedding of crossed cubes
(2003-11-30)
Yang, MC
;
Li, TK
;
Tan, JJM
;
Hsu, LH
;
資訊工程學系
The crossed cube CQ(n) introduced by Efe has many properties similar to those of the popular hypercube. However, the diameter of CQ(n) is about one half of that of the hypercube. Failures of links and nodes in an interconnection network are inevitable. Hence, in this paper, we consider the hybrid fault-tolerant capability of the crossed cube. Letting f(e) and f(v) be the numbers of faulty edges and vertices in CQ(n), we show that a cycle of length 1, for any 4 less than or equal to l less than or equal to V(CQ(n)) - f(v) can be embedded into a wounded crossed cube as long as the total number of faults (f(v) +f(e)) is no more than n - 2, and we say that CQ(n) is (n - 2)-fault-tolerant pancyclic. This result is optimal in the sense that if there are n - 1 faults, there is no guarantee of having a cycle of a certain length in it. (C) 2003 Published by Elsevier B.V.
Fault-tolerant pancyclicity of the Mobius cubes
(2005-01-01)
Yang, MC
;
Li, TK
;
Tan, JJM
;
Hsu, LH
;
資訊工程學系
The Mobius cube MQ(n) proposed by Cull et al. is an alternative to the popular hypercube network. Recently, MQ(n) was shown to be pancyclic, i.e., cycles of any,lengths at least four can be embedded into it. Due to the importance of the fault tolerance in the parallel processing area, in this paper, we study an injured MQ(n) with mixed node and link faults. We show that it is (n - 2)-fault-tolerant pancyclic for n greater than or equal to 3, that is, an injured n-dimensional MQ(n) is still pancyclic with up to (n - 2) faults. Furthermore, our result is optimal.
Hemocompatibility and anaphylatoxin formation of protein-immobilizing polyacrylonitrile hemodialysis membrane
(2005-04-01)
Liu, TY
;
Lin, WC
;
Huang, LY
;
Chen, SY
;
Yang, MC
Plasma proteins were covalently immobilized onto polyacrylonitrile (PAN) membrane to evaluate the hemocompatibility and anaphylatoxin formation. This is used as a model to study the effect of protein-adsorption on the blood-contacting response of hemodializing membranes. The proteins used were either platelet-adhesion-promoting collagen (COL) or platelet-adhesion-inhibiting human serum albumin (HSA). The microstructure and characterization of the protein-immobilizing PAN membranes were evaluated by Coomassie dye assay, atomic force microscopy, X-ray photoelectron spectroscopy and water contact angle measurement. PAN-HSA membrane improved not only hemocompatibility including less platelet adhesion, longer blood coagulation times, and higher thrombin inactivity level, but also induced lower complement activation. On the other hand, PAN COL membrane exhibited blood incompatibility, although induced less increase of C3, C4 antigens of serum. Overall results of this study demonstrated that the immobilization of HSA onto the surface of PAN membrane would be beneficial to improve the hemocompatibility and to reduce the anaphylatoxin formation during hemodialysis. (C) 2004 Elsevier Ltd. All rights reserved.
In-plane free vibration and stability of loaded and shear-deformable circular arches
(2003-11-01)
Huang, CS
;
Nieh, KY
;
Yang, MC
;
土木工程學系
;
Department of Civil Engineering
The first known equations governing vibrations of preloaded, shear-deformable circular arches are derived according to a variational principle for dynamic problems concerning an elastic body under equilibrium initial stresses. The equations are three partial differential equations with variable coefficients. The governing equations are solved for arches statically preloaded with a uniformly distributed vertical loading, by obtaining a static, closed-form solution and an analytical dynamic solution from series solutions and dynamic stiffness matrices. Convergence to accurate results is obtained by increasing the number of elements or by increasing both the number of terms in the series solution and the number of terms in the Taylor expansion of the variable coefficients. Graphs of non-dimensional frequencies and buckling loads are presented for preloaded clamped arches. They clarify the effects of opening angle and thickness-to-radius ratio on vibration frequencies and buckling loads. The effects of static deformations on vibration frequencies are also investigated. This work also compares the results obtained from the proposed governing equations with those obtained from the classical theory neglecting shear deformation. (C) 2003 Elsevier Ltd. All rights reserved.
Miscibility, thermal characterization and crystallization of poly(L-lactide) and poly(tetramethylene adipate-co-terephthalate) blend membranes
(2005-12-12)
Liu, TY
;
Lin, WC
;
Yang, MC
;
Chen, SY
;
材料科學與工程學系
Binary blend membranes of biodegradable poly(L-lactide) (PLLA) with poly(tetramethylene adipate-co-terephthalate) (PTAT) copolymer were prepared by solution casting via air evaporation. The miscibility of PLLA/PTAT blends was studied by dynamic mechanical analysis (DMA) and thermal mechanical analysis (TMA) in a tensile mode. Differential scanning calorimetry (DSC) measurement was carried out. The surface microstructure and tensile properties of the blend membranes were examined using atomic force microscopy (AFM) and tensile tester. It was concluded that PLLA/PTAT blends should be partially miscible for all ranges of compositions. Higher roughness and porosity were observed for the blend containing 50% PTAT, suggesting more phase separation occurred. The DSC analysis showed that the fusion enthalpy and crystallinity (X-c) of the PLLA-rich phase decreased with increasing PTAT content. Solidification process strongly suggested that the crystallization rate was accelerated by blending with 25% PTAT content, which served as the nucleation agent. Furthermore, the crystallization rate coefficient (CRC) depended on the blending miscibility and cooling rate in the non-isothermal crystallization process. Besides, PTAT addition could be proved to enhance the thermal stability and elongation of resulting blend membranes, even superior to those properties of poly(lactic acid-co-glycolic acid) (PLGA). (c) 2005 Published by Elsevier Ltd.
On embed-ding cycles into faulty twisted cubes
(2006-03-22)
Yang, MC
;
Li, TK
;
Tan, JJM
;
Hsu, LH
;
資訊工程學系
The twisted cube TQ(n) is an alternative to the popular hypercube network. Recently, some interesting properties of TQ(n) were investigated. In this paper, we study the pancycle problem on faulty twisted cubes. Let f(e) and f(v) be the numbers of faulty edges and faulty vertices in TQ(n), respectively. We show that, with f(e) + f(v) <= n - 2, a faulty TQ(n) still contains a cycle of length l for every 4 <= l < V(TQ(n)) - f(v) and odd integer n >= 3. (C) 2005 Elsevier Inc. All rights reserved.
Surface characteristics and hemocompatibility of PAN/PVDF blend membranes
(2005-05-01)
Liu, TY
;
Lin, WC
;
Huang, LY
;
Chen, SY
;
Yang, MC
Polyacrylonitrile (PAN) was blended with polyvinylidine fluoride (PVDF) at various ratios and made into membranes. The hemocompatibility of the resulting membranes was evaluated based on human plasma proteins adsorption, platelet adhesion, thrombus formation, and blood coagulation time. The PAN/PVDF blends exhibited partial miscibility according to the inward shifting of their two glass transition temperatures. The microstructures of blend membranes examined using atomic force microscopy (AFM) indicated that the roughness increased with the PVDF content, and the phase separation was too severe to form a membrane when the PVDF content was more than 30%. The water contact angle of PAN/PVDF blend membranes increased with the PVDF content. By blending with 20wt% apolar PVDF the adsorption of blood proteins could be reduced, and hence the platelet adhesion and thrombus formation was also reduced. However, when the PVDF content was 30 wt%, severe thrombogenicity was observed due probably to the more porous structure of blend membrane. These results demonstrated that the hemocompatibility would be improved for PAN/PVDF blend membranes with appropriate hydrophilicity and roughness. Copyright (c) 2005 John Wiley & Sons, Ltd.