The objective of this research was to clarify the basis of subfertility in Delaware roosters. It was anticipated that a sensitive method would be needed to compare seminal plasma protein composition between subfertile and fertile roosters. Consequently, the applicability of two-dimensional electrophoresis was tested as a tool for the analysis of chicken seminal plasma proteins. Two-dimensional electrophoresis resolved 95 ± 4.4 derivative polypeptides from seminal plasma proteins of fertile roosters, whereas one-dimensional electrophoresis resolved only 23 ± 0.4. Thus, two-dimensional electrophoresis was found to be a useful tool for seminal plasma protein analysis. Seminal plasma composition was compared between subfertile Delaware and fertile roosters. Seminal plasma from subfertile roosters was characterized by an imbalance of proteins, electrolytes, and amino acids (P<0.05). Neither type of seminal plasma contained proteolytic activity. No difference (P>0.05) was observed in seminal plasma osmolality. Differences in seminal plasma composition were attributed to a dysfunction of the excurrent ducts of the testis. This realization lead to experiments designed to modulate subfertility. Hemicastration exacerbated (P<0.001) subfertility, whereas supplementation of spermatozoa with seminal plasma proteins from fertile roosters ameliorated (P<0.001) subfertility. Addition of seminal plasma proteins from subfertile roosters to spermatozoa from fertile roosters had no effect (P>0.05) on fertility. Therefore, subfertility was attributed to protein deficiency in seminal plasma rather than the presence of some agent that induces subfertility. The study of subfertile Delaware roosters has helped establish a link between seminal plasma proteins and fertility in the domestic fowl. / Graduation date: 1992

The major impact of this research lies in the aspect of improved design and long term biocompatibility of materials used for implants. There are two goals in this research. The first goal is to develop a methodology to quantitatively measure cell-material adhesion. The second goal is to obtain fundamental understanding of cell-material adhesion mechanisms. A rotating parallel disk is used to measure cell adhesion. The rotational system applies a controlled shear stress to the cultured cells. The shear stress experienced by the cells varies with radial location, being highest at the edge and zero at the disk?s center. There is a critical point along the radius where the shear stress experienced by the cells equals their adhesion strength. The cells outside it are removed and the cells inside it remain attached to the surface. NIH 3T3 Swiss mouse fibroblasts and chick retina neuron cells from 6-day embryos are used in this study. The fibroblasts were cultured on poly(methyl methacrylate) (PMMA), polycarbonate (PC), and on gold coated poly(vinylidene fluoride) (Au/PVDF). The critical shear stress for fibroblasts was the lowest for PC with 5.09 dynes/cm2 and highest for PMMA with 21.0 dynes/cm2. This four-fold difference is mainly due to the chemical structure of PMMA which promotes higher cell adhesion when compared to PC. Neurons were cultured on poly-D-lysine coated glass to promote cell adhesion. The critical shear stress of neuron cells varied from 3.94 to 27.8 dynes/cm2 these values are directly proportional to the applied shear stress. The neuron adhesion plateau at ~27 dynes/cm2 which indicates the maximum adhesion strength of the neuron/poly-D-lysine coated glass pair. This thesis contains six chapters. Chapter I describes the importance of cell adhesion for biocompatibility. Chapter II describes in more detail the goals of this research and the expected results. Chapter III lists all the materials, equipment, and methods used in this study. The most significant results are summarized in Chapter IV. The observations and results obtained are explained in detail in Chapter V and Chapter VI describes the key outcomes as well as proposes questions for the advancement of this research.

Stable retorted whey protein beverages with 5% protein concentration were prepared. The effect of protein concentration, fat concentration and homogenization pressure on the heat stability and the stability of emulsions of sterilized whey protein beverages was determined. Beverages containing >1% protein formed aggregates during the heat treatment. Food grade additives were added to the beverages with >1% protein to determine if the heat stability could be improved. Lecithins and polyphosphates improved the heat stability while hydrocolloids decreased the heat stability. Lecithins improved the heat stability of emulsions better than polyphosphates but polyphosphates were more effective in beverages without fat. Lecithins modified by acetylation or hydrolysis provided more protection against heat denaturation of proteins than regular lecithin. Acetylated lecithin created the emulsions most stable against creaming. Improvement in the emulsion stability by the use of phospholipids was associated with a more negative charge at the interface of the fat droplets. The effect of polyphosphates on the heat stability was related to the chain length of the polyphosphates. Short chain polyphosphates (dp~4) were more effective than other polyphosphates. Polyphosphates probably improved the heat stability of the systems by changing the structure of water and this prevented aggregation of whey proteins. Hydrocolloids decreased heat stability most probably through thermodynamic incompatibility that locally increased the concentration of proteins and promoted aggregation during the heat treatment.The effect of homogenization pressure, concentration of acetylated lecithin, and the concentration of short chain polyphosphate on the storage stability of retorted whey protein beverages containing 5% protein and 3% fat was determined. The creaming index and particle size index changed over 28 d of storage and indicated creaming of the emulsions. The use of homogenization pressures of 55 and 90 MPa compared to 20 MPa reduced the magnitude of the change of the particle size index and creaming index during storage. Inclusion of polyphosphates reduced the storage stability of the emulsions. Optimization of parameters showed that emulsions formulated with 5% protein, 3% fat and 0.3% lecithin without polyphosphates and homogenized at 90 MPa had the best stability after 28 d of storage.

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Thesis (M.Sc.)--York University, 2006. Graduate Programme in Biology. / Typescript. Includes bibliographical references (leaves 62-69). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR29595

Thesis (Ph. D.)--Ball State University, 2009. / Title from PDF t.p. (viewed on Nov. 12, 2009). Includes bibliographical references (p. 127-145).

Thesis (Ph.D.)--University of Delaware, 2009. / Principal faculty advisor: Christopher J. Roberts, Dept. of Chemical Engineering. Includes bibliographical references.

Thesis (M.Sc.)--York University, 2008. Graduate Programme in Kinesiology and Health Science. / Typescript. Includes bibliographical references (leaves 66-90). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR38743

Thesis (M.S.)--University of Delaware, 2009. / Principal faculty advisor: Henry R. Glyde, Dept. Physics & Astronomy. Includes bibliographical references.

Thesis (M.S.)--University of Delaware, 2009. / Principal faculty advisor: . Includes bibliographical references.