558 research outputs found

    Method Development for Measuring Cleaning Agent Efficiency at a Laboratory Scale. Cleaning agent efficiency in dissolution of UHT fouling at different concentrations and temperatures.

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    In the milk industry, the production must be stopped daily in order to clean the process equipment from deposits that are formed at the inside surface when the products are heat treated. This leads reduced production time since no products can be treated when the equipment are being cleaned. The heat treatment of milk products is necessary to ensure that the product is safe to consume. When heat treating the milk, certain compounds in the milk become unstable and form a deposit called fouling inside the heating equipment. This fouling layer reduces the heat transfer from the heat equipment to the product that is supposed to be heat treated. In order to remove the fouling deposit cleaning with first alkaline and then acidic detergent are used. It can take up to a few hours before the equipment is cleaned depending on the degree of fouling. The aim of this master’s thesis is to develop a laboratory method for measuring cleaning efficiency of UHT fouling by using cleaning detergents at different temperatures and concentrations. The method was created by looking on how a Cleaning-In-Place process is performed and imitates these steps at a laboratory level, by performing experiments on storage, drying, size and separation of fouling. The cleaning method was evaluated according to repeatability and ability to distinguish cleaning effects of the different cleaning liquids. A cleaning method for dissolution of UHT fouling was achieved where it was possible to detect trends of degree of dissolved fouling when different temperature and concentration of cleaning liquids were used in the sodium hydroxide step. The repeatability of the cleaning method was sufficient to be able to detect the cleaning trends. The cleaning effect trials showed that higher temperature and concentration leads to more fouling dissolved. It was also seen that with higher concentration of alkaline detergent a lower temperature could be used to achieve a similar cleaning compared to lower concentration of alkaline detergent

    Some Bayesian and non-Bayesian procedures for the analysis of comparative experiments and for small-area estimation: computational aspects, frequentist properties, and relationships

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    Let y represent an n x 1 observable random vector that follows the linear model y = X[beta] + Zs + e. Here X and Z are give matrices, [beta] is a vector of unknown parameters, and s and e are statistically independent random vectors that have multivariate normal distributions with mean vectors equal to 0 and covariance matrices [sigma][subscript]spe2 I and [sigma][subscript]sps2 I, respectively; so that E(y) = X[beta] and var(y) = [sigma][subscript]spe2( I + [gamma] ZZ[superscript]\u27), where [gamma] = [sigma][subscript]sps2/[sigma][subscript]spe2. The problem of interest is the prediction of the realization of a random variable of the form w = [lambda][superscript]\u27[beta] + [delta][superscript]\u27 s--we refer to this problem as the general prediction problem. Many inference problems, including the estimation of a treatment contrast and the estimation of a small-area mean, can be regarded as special cases of the general prediction problem;We consider both traditional (frequentist) and Bayesian approaches to the point and interval prediction of w. Our coverage of frequentist methodology includes the ordinary least squares approach to point prediction, the estimation of the variance components [sigma][subscript]spe2 and [sigma][subscript]sps2 (including restricted maximum likelihood estimation), and the use of variance-component estimates to obtain generalized least squares point predictors. Some exact and approximate prediction interval procedures, based on ordinary or generalized least squares point predictors, are also considered, and the computational aspects of their implementation is discussed;In applying the Bayesian approach to the general prediction problem, we specify a general class of prior distributions, derive the corresponding posterior distributions of w given y, and describe point and interval characterizations of the posteriors that can be used as predictors for w. We show how, by taking advantage of computational results for frequentist predictors, the normally severe computational requirements of the Bayesian approach can be reduced;The frequentist and Bayesian approaches to the mixed model are essentially equivalent to the hierarchical Bayes and empirical Bayes approaches as applied to the fixed model obtained by regarding s as a vector of unknown parameters rather than as a random vector. Thus, the frequentist predictors can be viewed as approximations to the various Bayesian predictors. We present the results of a Monte Carlo study of the frequentist properties of both the traditional and the Bayesian predictors as applied to inference about treatment contrasts and small-area means. The results suggest that the Bayesian approach produces point and interval predictors whose overall performance compares favorably with that of the frequentist predictors, and that there are applications where the Bayesian predictors should be used in preference to the frequentist predictors

    Studies of interactions with Streptococcus equi and the host

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    Streptococcus equi subspecies equi (S. equi) causes strangles, a highly contagious and serious disease in the upper respiratory tract of horses, with a worldwide distribution. Streptococcus equi subspecies zooepidemicus (S. zooepidemicus) is regarded as an opportunistic pathogen infecting horses and other animals, and is believed to be the ancestor of S. equi. Pathogenic bacteria have evolved excellent ways of escaping the immune system and other defence mechanisms or have adapted to efficiently colonise specific areas of the host. The overall objective of this thesis was to study the interaction between S. equi and S. zooepidemicus and the host. An important feature for establishment of an infection and survival of the microorganism inside the host is the interaction with, and adherence to, host tissues. In one of the studies, a group of extracellular proteins with sequence similarities with the fibronectin- and collagen-binding protein FNE, were identified and characterised. All of the proteins bound to collagen to different degrees, and one of the proteins, FNEE, was shown to bind both collagen and fibronectin, and mediate a collagen contraction in presence of PDGF-BB. In another study, an additional IgG endopeptidase of S. equi (and S. zooepidemicus), called IdeE2 (IdeZ2) was described. IdeE2 efficiently degrades horse IgG4, and together with another endopeptidase, this enzyme induced protection in a mouse infection model. In a continuation of the IdeE2/IdeZ2 study, on screening a panel of S. zooepidemicus isolates, sequence variation within the ideZ2 gene was discovered, resulting in three major gene variations. However, the variation in this gene did not reflect the origin of the isolates or the MLST group of the strain. Extended computer alignment with IdeS from S. pyogenes, revealed similarities to structures known to be important for endopeptidase activity. The recombinant proteins IdeZ212, IdeZ216 and IdeZ221 all degraded horse IgG highly efficient despite amino acid differences in between the proteins, which argues for the importance of these proteins in the infection process

    Multiple-input, multiple-output modeling of the human thermoregulatory system

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    The need for understanding the human thermoregulatory system has increased and so has the importance of developing accurate dynamic models for the thermoregulatory system. Historically, there have been mainly two modeling approaches for the human thermoregulatory system--theoretical and empirical. However, there are limitations to both of these approaches. The complexity and the lack of knowledge of the physiological behavior of the human body limit the theoretical approach. The empirical approach is unsuitable for practical use, due to the large amount of data requirements. This study is unique in the sense that it utilizes a new methodology that can develop accurate compact closed-from predictive models from a small amount of data. This work explores a new predictive modeling methodology developed for engineering processes that approximate the block-oriented Hammerstein structure. It is called the Hammerstein Block-oriented Exact Solution Technique (H-BEST) and is based on a compact, continuous-time, closed form solution that gives optimal (i.e., the smallest possible number) parameterization and preserves the form of the static gain functions. The approach that this study will take is to use the H-BEST for modeling of the skin temperature and sweat rate, by using the Wissler (1964) computer program as a surrogate human from an optimal (i.e. minimal) amount of experimental trials. The H-BEST models will help in addressing two major challenges faced when modeling the human thermoregulatory system. First, the H-BEST solution for the output responses will be used to significantly reduce the number of experimental trials per subject. Secondly, the H-BEST models will be used in optimal experimental design to significantly reduce the required time a subject needs to be in the environmental chamber for data collection. Statistical design of experiments and D-optimal criterion is used to solve these two problems. This study shows that there is much promise in using H-BEST when modeling human subjects

    Regional patterns of presettlement forests in the Boston mountains of northwest Arkansas

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    The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from title screen of research.pdf file viewed on (February 8, 2007)Includes bibliographical references.Thesis (M.A.) University of Missouri-Columbia 2006.Dissertations, Academic -- University of Missouri--Columbia -- Geography.While diverse, mixed mesophytic forests are primarily found in the Appalachian Highlands, strikingly similar forests are noted as occurring in protected slopes and coves within the Boston Mountains of northwestern Arkansas. This project uses General Land Office survey records predating extensive European settlement to reconstruct regional forest patterns. Survey records were digitized into a Geographic Information Systems database in order to interpolate land cover and forest types as well as map tree species distributions within the study area. The results of this project show that woodlands and closed canopy forests dominated the landscape. While the forests of the Boston Mountains were dominated by regionally typical oak and hickory species, results show the presence of a mixed mesophytic forest type. This species association was found in the most rugged and protecting portions of the study area and displayed many traits common in southern Appalachian mixed mesophytic forests

    Gene flow from single and stacked herbicide-resistant rice (\u3ci\u3eOryza sativa\u3c/i\u3e): Modeling occurrence of multiple herbicide-resistant weedy rice

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    Background: Provisia™ rice (PV), a non-genetically engineered (GE) quizalofop-resistant rice, will provide growers with an additional option for weed management to use in conjunction with Clearfield® rice (CL) production. Modeling compared the impact of stacking resistance traits versus single traits in rice on introgression of the resistance trait to weedy rice (also called red rice). Common weed management practices were applied to 2-, 3- and 4-year crop rotations, and resistant and multiple-resistant weedy rice seeds, seedlings and mature plants were tracked for 15 years. Results: Two-year crop rotations resulted in resistant weedy rice after 2 years with abundant populations (exceeding 0.4 weedy rice plants m–2) occurring after 7 years. When stacked trait rice was rotated with soybeans in a 3-year rotation and with soybeans and CL in a 4-year rotation, multiple-resistance occurred after 2–5 years with abundant populations present in 4–9 years. When CL rice, PV rice, and soybeans were used in 3- and 4-year rotations, the median time of first appearance of multiple-resistance was 7–11 years and reached abundant levels in 10–15 years. Conclusion: Maintaining separate CL and PV rice systems, in rotation with other crops and herbicides, minimized the evolution of multiple herbicide-resistant weedy rice through gene flow compared to stacking herbicide resistance traits

    Novel IgG-degrading enzymes of the IgdE protease family link substrate specificity to host tropism of <i>Streptococcus</i> species

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    Recently we have discovered an IgG degrading enzyme of the endemic pig pathogen S. suis designated IgdE that is highly specific for porcine IgG. This protease is the founding member of a novel cysteine protease family assigned C113 in the MEROPS peptidase database. Bioinformatical analyses revealed putative members of the IgdE protease family in eight other Streptococcus species. The genes of the putative IgdE family proteases of S. agalactiae, S. porcinus, S. pseudoporcinus and S. equi subsp. zooepidemicus were cloned for production of recombinant protein into expression vectors. Recombinant proteins of all four IgdE family proteases were proteolytically active against IgG of the respective Streptococcus species hosts, but not against IgG from other tested species or other classes of immunoglobulins, thereby linking the substrate specificity to the known host tropism. The novel IgdE family proteases of S. agalactiae, S. pseudoporcinus and S. equi showed IgG subtype specificity, i.e. IgdE from S. agalactiae and S. pseudoporcinus cleaved human IgG1, while IgdE from S. equi was subtype specific for equine IgG7. Porcine IgG subtype specificities of the IgdE family proteases of S. porcinus and S. pseudoporcinus remain to be determined. Cleavage of porcine IgG by IgdE of S. pseudoporcinus is suggested to be an evolutionary remaining activity reflecting ancestry of the human pathogen to the porcine pathogen S. porcinus. The IgG subtype specificity of bacterial proteases indicates the special importance of these IgG subtypes in counteracting infection or colonization and opportunistic streptococci neutralize such antibodies through expression of IgdE family proteases as putative immune evasion factors. We suggest that IgdE family proteases might be valid vaccine targets against streptococci of both human and veterinary medical concerns and could also be of therapeutic as well as biotechnological use

    Dysphonia - Illustrating a Nationwide Initiative to Provide Students with High Quality e-Learning Resources

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    Dysphonia is one of 16 e-learning projects coordinated and supported by the MedCal committee of the Council for Renewal of Higher Education. The application as such is a multimedia program about voice disorders and comprises a collection of patients suffering from hoarseness, which the user can explore in an interactive manner. The greatest benefits can be reaped by being able to integrate sound (voice) with images, video clips and descriptive text of various pathological conditions. Voice acoustic analysis is also provided. Each diagnosis is explicitly accounted for in classic textbook style. Descriptions of examination techniques, therapeutic sessions, and surgical interventions are included. The material can be accessed in multiple ways and supports explorative learning. The Dysphonia project is the product of a network of collaborators of various expertise supported by a nationwide initiative

    Advances in the treatment of prolactinomas

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    Prolactinomas account for approximately 40% of all pituitary adenomas and are an important cause of hypogonadism and infertility. The ultimate goal of therapy for prolactinomas is restoration or achievement of eugonadism through the normalization of hyperprolactinemia and control of tumor mass. Medical therapy with dopamine agonists is highly effective in the majority of cases and represents the mainstay of therapy. Recent data indicating successful withdrawal of these agents in a subset of patients challenge the previously held concept that medical therapy is a lifelong requirement. Complicated situations, such as those encountered in resistance to dopamine agonists, pregnancy, and giant or malignant prolactinomas, may require multimodal therapy involving surgery, radiotherapy, or both. Progress in elucidating the mechanisms underlying the pathogenesis of prolactinomas may enable future development of novel molecular therapies for treatment-resistant cases. This review provides a critical analysis of the efficacy and safety of the various modes of therapy available for the treatment of patients with prolactinomas with an emphasis on challenging situations, a discussion of the data regarding withdrawal of medical therapy, and a foreshadowing of novel approaches to therapy that may become available in the future
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