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1. The digestive gland of the scallop Pecten maximus naturally contains a very high concentration of cadmium (100 ppm wet weight), which does not show individual or seasonal variations. 2. About 60% of the tissue cadmium is soluble (i.e. is found in the supernatant when homogenate is centrifuged for 1 hour at 100,000g) and is bound to three main types of macromolecule. Most (about 60%) of this metal is associated with a component of molecular weight 55,000, the rest being bound to a low molecular weight species and, probably non-specifically, to components of very high molecular weight (greater than 100,000 molecular weight). The latter components were not further characterised. 3 The major binding component complexes the Cd2+ via sulphydryl groups, and so has a high cysteine content, but the binding is weaker than that of cadmium to metallothionein. The component has a high content of glutamate and aspartate (or their amides) and contains aromatic amino acids. It may also have a small carbohydrate content.4. The major cadmium binding component was susceptible to degradation by endogenous proteolytic enzymes. A major digestive enzyme was identified as a chymotrypsin which could be inactivated with phenylmethanesulphonylfluoride. Addition of PMSF to the homogenate reduced the total proteolytic activity of the digestive gland cytosol by up to 75%. Attempts to further inhibit, or remove, the remaining protease activity were largely unsuccessful. Probably as a result of the action of the proteolytic enzymes on the major cadmium component efforts to isolate the latter were characterised by irreproducibility, and satisfactory purification was not achieved. 5. The low molecular weight cadmium binding component binds 10-15% of the total soluble cadmium and exhibits many of the characteristics of a metallothionein. It has an apparent molecular weight of 10,000 on gel exclusion chromatography, high cadmium and cysteine contents and a high A250/A280 ratio. It is also heat stable and contains copper and zinc as well as cadmium. It can be detected by the metallothionein assay of Eaton & Toal (1982). 6. Preparations of both the major Cd binding component and metallo-thionein-like component contained relatively large amounts of carbohydrate, but the latter was probably not associated with these proteins. Its origin is unknown.

Yung Ka Shing, Ivan. / Thesis submitted in: November 2000. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 142-154). / Abstracts in English and Chinese. / Acknowledgement --- p.i / Abstract (English version) --- p.ii / Abstract (Chinese version) --- p.iv / List of Tables --- p.vi / List of Figures --- p.vii / Content --- p.x / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Biology of scallops --- p.1 / Chapter 1.1.1 --- Structure and Function --- p.1 / Chapter 1.1.2 --- Acquisition and Utilization of Energy --- p.2 / Chapter 1.1.3 --- Physiology of Reproduction --- p.3 / Chapter 1.2 --- Methods of Cultivation --- p.4 / Chapter 1.2.1 --- Hanging Culture --- p.4 / Chapter 1.2.2 --- Bottom Culture --- p.5 / Chapter 1.3 --- Selected Processing Methods --- p.6 / Chapter 1.3.1 --- Freezing and Frozen Storage --- p.6 / Chapter 1.3.2 --- Drying --- p.8 / Chapter 1.4 --- Lipids of Scallops --- p.9 / Chapter 1.5 --- Volatile Components of Scallops --- p.9 / Chapter 1.5.1 --- Volatile Components of Scallops --- p.9 / Chapter 1.5.2 --- Alcohols --- p.10 / Chapter 1.5.3 --- Aldehydes --- p.11 / Chapter 1.5.4 --- Ketones --- p.12 / Chapter 1.5.5 --- Nitrogen-Containing Compounds --- p.13 / Chapter 1.5.6 --- Sulfur-Containing Compounds --- p.14 / Chapter 1.5.7 --- Free Fatty Acids --- p.15 / Chapter 1.6 --- Taste Active Components of Scallops --- p.15 / Chapter 1.7 --- Objectives of Study --- p.17 / Chapter 2. --- Volatile Components of Dried Chinese and Japanese Scallops --- p.19 / Chapter 2.1 --- Introduction --- p.19 / Chapter 2.2 --- Materials and Methods --- p.20 / Chapter 2.2.1 --- Materials --- p.20 / Chapter 2.2.2 --- Methods --- p.20 / Chapter 2.2.2.1 --- Regular Simultaneous Steam Distillation-Solvent Extraction (R-SDE) ´ؤ Boiling --- p.20 / Chapter 2.2.2.2 --- Modified Simultaneous Steam Distillation-Solvent Extraction (M-SDE) - Steaming --- p.21 / Chapter 2.2.2.3 --- Gas Chromatography/Mass Spectrometry (GC/MS) --- p.21 / Chapter 2.2.2.4 --- Compound Identification --- p.23 / Chapter 2.2.2.5 --- Compound Quantification --- p.23 / Chapter 2.2.2.6 --- Statistical Analysis --- p.24 / Chapter 2.3 --- Results and Discussion --- p.24 / Chapter 2.3.1 --- Acids --- p.24 / Chapter 2.3.2 --- Aldehydes --- p.33 / Chapter 2.3.3 --- Alkanes --- p.34 / Chapter 2.3.4 --- Aromatics Compounds --- p.35 / Chapter 2.3.5 --- Naphthalenes --- p.35 / Chapter 2.3.6 --- Esters --- p.36 / Chapter 2.3.7 --- Furans --- p.36 / Chapter 2.3.8 --- Miscellaneous Compounds --- p.37 / Chapter 2.3.9 --- Alcohols --- p.38 / Chapter 2.3.10 --- Ketones --- p.39 / Chapter 2.3.11 --- Pyrazines and Pyridines --- p.40 / Chapter 2.3.12 --- Sulfur-Containing Compounds --- p.41 / Chapter 2.3.13 --- Terpenes --- p.42 / Chapter 2.3.14 --- Comparison between Boiling and Steaming Methods --- p.42 / Chapter 2.3.15 --- Comparison between Dried Chinese and Dried LL Grade Japanese Scallops --- p.43 / Chapter 2.3.16 --- Threshold Values and Odor Values of Some Identified Compounds --- p.45 / Chapter 2.4 --- Conclusion --- p.45 / Chapter 3. --- Volatile Components of Dried and Frozen Japanese Scallops --- p.69 / Chapter 3.1 --- Introduction --- p.69 / Chapter 3.2 --- Materials and Methods --- p.69 / Chapter 3.2.1 --- Materials --- p.69 / Chapter 3.2.2 --- Methods --- p.70 / Chapter 3.2.2.1 --- Regular Simultaneous Steam Distillation-Solvent Extraction (R-SDE) - Boiling --- p.70 / Chapter 3.2.2.2 --- Modified Simultaneous Steam Distillation-Solvent Extraction (M-SDE) - Steaming --- p.70 / Chapter 3.2.2.3 --- Gas Chromatography/Mass Spectrometry (GC/MS) --- p.72 / Chapter 3.2.2.4 --- Compound Identification --- p.72 / Chapter 3.2.2.5 --- Compound Quantification --- p.73 / Chapter 3.2.2.6 --- Statistical Analysis --- p.73 / Chapter 3.3 --- Results and Discussion --- p.73 / Chapter 3.3.1 --- Acids --- p.81 / Chapter 3.3.2 --- Aldehydes --- p.81 / Chapter 3.3.3 --- Alkanes --- p.82 / Chapter 3.3.4 --- Aromatics Compounds --- p.83 / Chapter 3.3.5 --- Naphthalenes --- p.83 / Chapter 3.3.6 --- Esters --- p.84 / Chapter 3.3.7 --- Furans --- p.84 / Chapter 3.3.8 --- Miscellaneous Compounds --- p.85 / Chapter 3.3.9 --- Alcohols --- p.85 / Chapter 3.3.10 --- Ketones --- p.86 / Chapter 3.3.11 --- Pyrazines and Pyridines --- p.87 / Chapter 3.3.12 --- Sulfur-Containing Compounds --- p.88 / Chapter 3.3.13 --- Terpenes --- p.89 / Chapter 3.3.14 --- Comparison between Boiling and Steaming Methods --- p.89 / Chapter 3.3.15 --- Comparison between Dried SA Grade and Frozen Japanese Scallops --- p.91 / Chapter 3.3.16 --- Threshold Values and Odor Values of Some Identified Compounds --- p.92 / Chapter 3.4 --- Conclusion --- p.92 / Chapter 4. --- 5´ة-Nucleotides of Dried and Frozen Scallops --- p.116 / Chapter 4.1 --- Introduction --- p.116 / Chapter 4.2 --- Materials and Methods --- p.116 / Chapter 4.2.1 --- Materials --- p.116 / Chapter 4.2.2 --- Methods --- p.117 / Chapter 4.2.2.1 --- Sample Preparation --- p.117 / Chapter 4.2.2.2 --- Perchloric Acid Treatment --- p.117 / Chapter 4.2.2.3 --- High Performance Liquid Chromatography (HPLC) --- p.118 / Chapter 4.2.2.4 --- Compound Identification --- p.118 / Chapter 4.2.2.5 --- Compound Quantification --- p.119 / Chapter 4.3 --- Results and Discussion --- p.119 / Chapter 4.4 --- "5´ة-Nucleotides, IMP and GMP in Other Seafoods" --- p.123 / Chapter 4.5 --- Conclusion --- p.125 / Chapter 5. --- Overview of Volatile Components and 5'-Nucleotides among Scallops --- p.131 / Chapter 5.1 --- Volatile Components --- p.131 / Chapter 5.1.1 --- Qualitative Differences among the Scallops --- p.131 / Chapter 5.1.1.1 --- Acids and Alkanes --- p.131 / Chapter 5.1.1.2 --- Aldehydes --- p.131 / Chapter 5.1.1.3 --- Aromatics Compounds and Naphthalenes --- p.132 / Chapter 5.1.1.4 --- Esters and Miscellaneous Compounds --- p.132 / Chapter 5.1.1.5 --- Alcohols --- p.133 / Chapter 5.1.1.6 --- Ketones --- p.133 / Chapter 5.1.1.7 --- Sulfur-Containing Compounds and Terpenes --- p.134 / Chapter 5.1.1.8 --- "Pyrazines, Pyridines and Furans" --- p.134 / Chapter 5.1.2 --- Quantitative Differences among the Scallops --- p.134 / Chapter 5.1.2.1 --- "Acids, Aldehydes and Alkanes" --- p.134 / Chapter 5.1.2.2 --- Aromatics Compounds and Naphthalenes --- p.135 / Chapter 5.1.2.3 --- Esters and Furans --- p.135 / Chapter 5.1.2.4 --- Alcohols and Ketones --- p.135 / Chapter 5.1.2.5 --- Pyrazines and Pyridines --- p.136 / Chapter 5.1.2.6 --- Sulfur-Containing Compounds and Terpenes --- p.136 / Chapter 5.1.2.7 --- Miscellaneous Compounds --- p.137 / Chapter 5.1.3 --- Internal and External Factors That Affect the Quality of the Scallops --- p.137 / Chapter 5.1.4 --- Comparison Between Boiling and Steaming Methods --- p.138 / Chapter 5.1.5 --- Comparison of Potent Aroma Contributors Among Scallops --- p.138 / Chapter 5.2 --- "5-Nucleotides, IMP and GMP" --- p.139 / Chapter 5.3 --- Conclusion --- p.140 / References --- p.142 / Appendices --- p.155 / Moisture content of the four scallops samples --- p.155

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Thesis (M.S.)--University of North Carolina at Wilmington, 2006.

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Impellers are important components in the field of precision machine, energy technology, and aerospace industries. Due to their complex geometries and a higher degree of interference, multi-axis machines are requested to product impellers with desired accuracy. The object of this thesis is to improve the five-axis machining efficiency and accuracy. The involved techniques include: the construction of equal depth and equal width tool paths in rough machining, the methods for interference check and avoidance, error evaluation and control of chordal deviation and scallop height, as well as three and five dimension NURBS (Non-uniform Rational B-splines) tool paths generation by a least squares method.