Variations in total and differential milk somatic cell counts and plasmin levels and their role in proteolysis and quality of milk and cheese

Increased plasmin and plasminogen levels and elevated somatic cell counts (SCC) and polymorphonuclear leucocyte levels (PMN) were evident in late lactation milk. Compositional changes in these milks were associated with increased SCC. The quality of late lactation milks was related to nutritional status of herds, with milks from herds on a high plane of nutrition having composition and clotting properties similar to, or superior to, early-mid lactation milks. Nutritionally-deficient cows had elevated numbers of polymorphonuclear leucocytes (PMNs) in their milk, elevated plasmin levels and increased overall proteolytic activity. The dominant effect of plasmin on proteolysis in milks of low SCC was established. When present in elevated numbers, somatic cells and PMNs in particular had a more significant influence on the proteolysis of both raw and pasteurised milks than plasmin. PMN protease action on the caseins showed proteolysis products of two specific enzymes, cathepsin B and elastase, which were also shown in high SCC milk. Crude extracts of somatic cells had a high specificity on αs1-casein. Cheeses made from late lactation milks had increased breakdown of αs1-casein, suggestive of the action of somatic cell proteinases, which may be linked to textural defects in cheese. Late lactation cheeses also showed decreased production of small peptides and amino acids, the reason for which is unknown. Plasmin, which is elevated in activity in late lactation milk, accelerated the ripening of Gouda-type cheese, but was not associated with defects of texture or flavour. The retention of somatic cell enzymes in cheese curd was confirmed, and a potential role in production of bitter peptides identified. Cheeses made from milks containing high levels of PMNs had accelerated αs1-casein breakdown relative to cheeses made from low PMN milk of the same total SCC, consistent with the demonstrated action of PMN proteinases. The two types of cheese were determined significantly different by blind triangle testing.

Simplified decoding techniques for linear block codes

Error correcting codes are combinatorial objects, designed to enable reliable transmission of digital data over noisy channels. They are ubiquitously used in communication, data storage etc. Error correction allows reconstruction of the original data from received word. The classical decoding algorithms are constrained to output just one codeword. However, in the late 50’s researchers proposed a relaxed error correction model for potentially large error rates known as list decoding. The research presented in this thesis focuses on reducing the computational effort and enhancing the efficiency of decoding algorithms for several codes from algorithmic as well as architectural standpoint. The codes in consideration are linear block codes closely related to Reed Solomon (RS) codes. A high speed low complexity algorithm and architecture are presented for encoding and decoding RS codes based on evaluation. The implementation results show that the hardware resources and the total execution time are significantly reduced as compared to the classical decoder. The evaluation based encoding and decoding schemes are modified and extended for shortened RS codes and software implementation shows substantial reduction in memory footprint at the expense of latency. Hermitian codes can be seen as concatenated RS codes and are much longer than RS codes over the same aphabet. A fast, novel and efficient VLSI architecture for Hermitian codes is proposed based on interpolation decoding. The proposed architecture is proven to have better than Kötter’s decoder for high rate codes. The thesis work also explores a method of constructing optimal codes by computing the subfield subcodes of Generalized Toric (GT) codes that is a natural extension of RS codes over several dimensions. The polynomial generators or evaluation polynomials for subfield-subcodes of GT codes are identified based on which dimension and bound for the minimum distance are computed. The algebraic structure for the polynomials evaluating to subfield is used to simplify the list decoding algorithm for BCH codes. Finally, an efficient and novel approach is proposed for exploiting powerful codes having complex decoding but simple encoding scheme (comparable to RS codes) for multihop wireless sensor network (WSN) applications.

The evolution of the medical professions in eighteenth-century Ireland: An institutional perspective

Ireland, in the eighteenth century, followed the classic tripartite division of regular medical practitioners into physicians, surgeons and apothecaries. At the beginning of the century surgeons and apothecaries were regarded as mere tradesmen, but by the end of the century both were regarded as professionals and had the right to regulate their respective professions. Practitioners in different regions of Europe developed in a different manner, and eighteenth-century practitioners in Ireland developed independently from their English counterparts. In common with Britain and Europe in the eighteenth century, the total number of practitioners increased in Ireland, and by the end of the century, apothecaries were the largest group in Dublin, closely followed by the surgeons. Surgeons and apothecaries at the start of the eighteenth century belonged to the same guild. However in mid-century, St Luke's guild of apothecaries was established and this provided the apothecaries with a new identity that allowed them to pursue auto regulation, rather than hitherto, when they had been regulated by the physicians. This was vital to the apothecaries as they were in direct commercial competition with both the physicians and the surgeons and faced increasing pressure from both druggists and the disparate group of practitioners known as the irregulars. The 1765 County Infirmaries Act established a hospital in virtually every county in Ireland, and cast the surgeon as the primary medical officer in the countrywide network of hospitals. This legislation, which was unique in Europe, had the unintended consequence of elevating the status of the surgeons, as prior to this physicians were always in the ascendancy in the voluntary hospitals in Ireland and Britain, in contrast to France. The status of the surgeons was further enhanced by the establishment of the College of Surgeons in Ireland in 1784, which provided them with a new corporate identity, the authority to regulate the profession countrywide, and, also, the ability to educate surgeons in Ireland. The establishment of the College of Surgeons placed further pressure on the apothecaries to demonstrate that they also had a recognisable identity, and the authority to regulate their own profession. This was achieved with the 1791 Apothecaries Act which established the Apothecaries Hall and give the apothecaries the right to regulate themselves. This innovative legislation deemed the apothecaries a profession, and was enacted twenty-four years prior to similar legislation in Britain. Commercial pressure from druggists and, probably, irregulars expedited the requirement of the apothecaries to establish a new corporate identity, in order to distance themselves from these groups. The changing status of both apothecaries and surgeons had little effect on the physicians as a group, and, despite being the beneficiaries of a generous bequest from Sir Patrick Dun in 1711 to provide medical chairs in Dublin, the physicians displayed an inertia during the eighteenth century that was not in keeping with the developments that occurred in the contemporary Dublin medical world. The fact that it took ninety-five years, and that five acts of parliament, two House of Commons enquiries and a House of Lords enquiry were required to ensure that Dun's wishes were brought to fruition demonstrates that the physicians did not develop at the same pace as the other medical groups in the city. Had Dun’s bequest been implemented as he desired, Dublin, with a number of voluntary hospitals, would have been well placed to provide comprehensive tuition for medical students in the eighteenth century. It was not until the nineteenth century that the city, and the populace, benefited from this legacy. This thesis will trace these developments in the context of changes that occurred in contemporary medical education and diagnosis in Ireland, Britain and France. It will demonstrate that Irish practitioners developed independently, influenced mainly by local issues, but also by those who had travelled abroad and returned to Ireland with new concepts and ideas, ensuring that Irish medical practitioners had the institutional structure that could encompass the diagnostic and regulatory changes that would become accepted in the nineteenth century.