Best Selling Books by Lee Cohen

A clear and concise guide to Nature''s Medicine based on scientific evidence. A must read for anyone interested in finding their own fountain of youth.

Rip Squeak and his little sister throw a surprise party for his mom and dad.

A child and her parents find different animals to view at the zoo.

(Cont.) We find no evidence that cost-sharing reduces wastage on those that will not use the good: women who received free nets are not less likely to use them than those who paid subsidized positive prices. Cost-sharing does, however, considerably dampen demand. We find that uptake drops by 75 percent when the price of ITNs increases from zero to 75 cents, the price at which ITNs are currently socialmarketed. When the price is between 15 and 30 cents, we observe that pregnant women who purchase an ITN are, on average, in poorer health than those who receive a free ITN. However, in absolute terms, the number of sick women getting access to an ITN at these prices is roughly the same as under free distribution, and the number of sick women getting access to an ITN at the current cost-sharing price is at least 47 percent lower than under free distribution. We use these estimates in a cost-effectiveness analysis of ITN prices on infant mortality that incorporates both private and social returns of ITN usage. Overall, given the large positive externality associated with widespread usage of insecticide-treated nets, our results suggest that free distribution is both more effective and more cost-effective than cost-sharing.

Oligosaccharides, carbohydrates with a degree of polymerization of three to 20, are important health-promoting factors, and play a role in cultivating humans’ gut microbiota. The most abundant source of these oligosaccharides is human milk. Human milk oligosaccharides have been attributed roles in developing a healthy gut microbiota and immune system, providing defense against pathogens, and other proposed systemic benefits. These molecules are recent targets clinically and commercially due to their unique specificity. However, isolating oligosaccharides from human milk as well as ruminants’ milk is challenging due to the similarity in size and molecular nature with lactose. Bovine milk, while low in oligosaccharide concentration, is produced in large enough quantities that commercial isolation may be possible with appropriate technology, especially considering the large volumes of dairy streams. Whey, a co-product of cheesemaking, is typically processed to isolate whey proteins, generating a co-product known as whey permeate. Whey permeate, a low-value co-product, is a potential source of bovine milk oligosaccharides. In addition to free bovine milk oligosaccharides in whey permeate, many proteins found naturally in whey are glycosylated, and using novel enzymes, these glycans may be released and isolated as bioactive oligosaccharides. This dissertation focuses on methods to isolate bovine milk oligosaccharides at pilot scale and proposes new methods to release glycans from whey proteins. Chapter 1 presents the historical and current utilization of whey permeate generated in the dairy industry, and highlights proposed biotechnological utilizations by which value can be added to this stream. This contextualizes multiple outlets for whey permeate that facilitate isolation of naturally occurring oligosaccharides and use of lactose as a feedstock in industrial biotechnology or in the food industry. Chapter 2 presents an optimized method of hydrolyzing the lactose, with multiple operational parameters taken into account. Preservation of sialylated bovine milk oligosaccharides was considered in this investigation. This chapter also includes a preliminary screening of nanofiltration membranes to determine suitability for retention of oligosaccharides and removal of monosaccharides, with permeate flux and transmembrane pressure considered as well. The optimal membrane and hydrolysis parameters from chapter 2 were used in chapter 3 to evaluate the selectivity of the sulfonated polyethersulfone membrane under various conditions. Specifically, pH of the feed material and transmembrane pressure were altered. Higher transmembrane pressure and pH favored monosaccharide permeation and oligosaccharide retention, both of which were favorable for oligosaccharide purification. This technique was validated at larger scale with diafiltration to further purify the oligosaccharides. Another approach to oligosaccharide isolation was developed in chapter 4, wherein lactose was hydrolyzed into glucose and galactose and Saccharomyces cerevisiae was used to ferment these monosaccharides. As this organism is incapable of metabolizing oligosaccharides, the resulting fermentation broth was concentrated using nanofiltration. This process was taken from bench scale to pilot scale, wherein a concentration factor of 20 was achieved. Glycoproteins in whey are another source of bioactive oligosaccharides in dairy co-products. The glycans can be released from the protein backbone enzymatically, and for commercial use, immobilization of these enzymes is attractive because the enzyme can be used in different reactor configurations and reused multiple times. Chapter 5 is a review of techniques for enzyme immobilization in the food industry and for glycosidases in particular, highlighting the challenges involved. Chapter 6 applies this knowledge to develop a method for immobilization of a novel endo-[beta]-N-acetylglucosaminidase for use on whey glycoproteins. Covalent binding to a methacrylate support was used to immobilize the enzyme, while a mass spectrometry-based method was used to evaluate the enzyme activity on a model glycoprotein, kinetic parameters were determined, and the system was evaluated on whey proteins. An LC-MS method was used to characterize the released glycans. Chapter 7 concludes the dissertation with a perspective on future challenges faced by the dairy industry with respect to co-product management. Mother liquor is a co-product of lactose crystallization from whey permeate, and represents a potential future feedstock for BMO isolation. Challenges of utilizing mother liquor due to its high mineral and lactose content, as well as possible outlets and room for technology development are discussed. Overall, this dissertation provides multiple techniques for isolating bovine milk oligosaccharides at pilot scale, allowing the investigation of their bioactive properties for mechanistic studies as well as commercial application as an ingredient. Additionally, methods for analyzing milk glycans are presented, as well as a thorough review of biotechnological applications of whey permeate and mother liquor, and potential methods and uses of immobilized glycosidases.

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