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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
381

Occurence of pathogenic and indicator microorganisms on produce irrigated with dairy wastewater

Manshadi, Faezeh Dehghan January 2003 (has links)
This project was designed to assess the potential for contamination of produce during irrigation with wastewater from animal operations. Dairy wastewater from the University of Arizona Campus Dairy Research Center was used to irrigate three different types of vegetable crops: lettuce, carrot, and bell pepper. This study was conducted over two consecutive years. The crops were planted in February and vegetables were harvested from May through July. Irrigation water and vegetable samples were examined for Escherichia coli, Clostridium perfringens, Listeria monocytogenes, and coliphage. In the dairy wastewater, E. coli concentrations averaged 5.7 x 10⁵ MPN/100 mL in the first year (2000), and 9.9 x 10⁷ MPN/100 mL in the second year (2001). C. perfringens concentrations were nearly the same in both years (1.7 x 10⁴ and 3.4 x 10⁴ CFU per 100 mL). Coliphage averaged 2.0 PFU/mL in 2000 and 1.3 x 10⁴ PFU/mL in 2001 in wastewater. E. coli was detected with greater frequency on carrots (100 and 96%) succeeded by lettuce (67 and 96%) and bell peppers (63 and 58%). The same was true for C. perfringens : carrots (100%), lettuce (86 and 88%), and bell peppers (100 and 50%). Coliphages were not detected on any of the vegetable crops except for average concentrations of 2 PFU/g on lettuce in the first year. L. monocytogenes was not detected on any of the vegetable samples. ANOVA test results indicates that E. coli and C. perfringens concentrations on three crops were statistically different (p < 0.0001) which suggest that the degree of contamination on the surface of the vegetables depends on where the edible portion of the crop is situated (above the soil or under the soil). The greatest contamination occurred on the carrots followed by lettuce and bell peppers. E. coli and C. perfringens were recovered from the carrots, bell peppers, and soil 55 days after wastewater irrigation of the plots had ceased. Positive correlations (p < 0.05) were found between E. coli and C. perfringens density and soil moisture content. The greatest risk of infection from pathogenic E. coli (O157:H7) occurs from consumption of lettuce and carrots. The annual risk of infection from consumption of all three vegetables was above the acceptable risk of 1:10,000 per year. The results of this study suggest that a more strict irrigation water quality standard for root and leafy vegetables might be appropriate to prevent the risk of infection in exposed population.
382

Soft wheat pasta supplemented with cowpea: Nutritional, sensory and cooking quality studies

Bergman, Christine Joy, 1960- January 1990 (has links)
Pasta was produced from soft wheat supplemented with cowpea. Acid detergent fiber values increased from 0.4% in the soft wheat pasta (SWP) to 1.1% in the 30% cowpea pasta (CP). Cowpea supplementation provided an increase in total and available lysine from 42 to 113% and 39 to 117%, respectively. Chemical scores for preschool children increased from 56 in the SWP to 89 in the 30% CP. For school children the 20% CP provided a score of 102. The in vitro protein digestibility (IVPD) of cowpea was lower than that of soft wheat; as a result cowpea reduced the IVPD of SWP from 84% to a value of 78% for the 30% CP. The protein content of SWP was 10.9% while the CP ranged from 11.3 to 14.2%. Considering IVPD values, SWP contained 9.2% digestible protein and CP from 9.2 to 11.1%. After cooking, only the 30% CP displayed trypsin inhibitor activity. Upon visual examination, cowpea improved the color of SP making it comparable to the durum semolina control (DSC) but lacking its translucency. A sensory panel reported no difference in acceptability among treatments. Cooked weights were similar to the SWP, except with 30% replacement when a decrease was observed. CP, after 10 minutes of cooking demonstrated reduced loss as supplementation was increased. After 20 minutes all treatments had similar cooking loss compared to the SP. All treatments displayed cooking quality results significantly different from the DSC.
383

Focused Ion Beam Nanomachining of Thermoplastic Polymers

Wong, Ka Chun 02 May 2013 (has links)
<p> Commercially available Ga<sup>+</sup> focused ion beam (FIB) instruments with nanometer size probe allows for in situ materials removal (sputtering) and addition (deposition) on a wide range of material. These spatially precise processes have enabled a wide range of nanofacbrication operations (e.g. specimen preparation for analysis by scanning electron microscope, transmission electron microscope, and secondary ion mass spectrometer). While there exists an established knowledge of FIB methods for sample preparation of hard materials, but FIB methodology remain underdeveloped for soft materials such as biological and polymeric materials. </p><p> As FIB is increasingly utilized for specimen preparation of polymeric materials, it is becoming necessary to formulate an information base that will allow established FIB techniques to be generalized to this spectrum of materials. A thorough understanding of the fundamental ion-solid interactions that govern the milling process can be instrumental. Therefore, in an effort to make the existing procedures more universally applicable, the interrelationships between target material, variable processing parameters, and process efficiency of the milling phenomena are examined. The roles of beam current, distance (i.e. step size) between successive FIB beam dwell and the time it spent at each dwell point (i.e. pixel dwell time) are considered as applied to FIB nanomachining of four different thermoplastic polymers: 1. low density polyethylene (LDPE), 2. high density polyethylene (HDPE), 3. Polystyrene (PS), and 4. nylon 6 (PA6). Careful characterization of such relationships is used to explain observed phenomena and predict expected milling behaviors, thus allowing the FIB to be used more efficiently with reproducible results. Applications involving different types of polymer composite fiber are presented.</p>
384

Science-based Health Innovation in Sub-Saharan Africa

Al-Bader, Sara 14 December 2011 (has links)
Policy making bodies are increasingly highlighting the important role innovation can play in African development─not only to spur economic growth but also to deliver locally relevant, affordable products and services to African populations. The health sector is one area where innovation is most needed; however, we know very little about the capacity of African countries to innovate in this area. At the same time, a range of conceptual questions have arisen in the academic literature as to the very definition of innovation in an African context, and specifically, the applicability of the National Innovation System (NIS) to African countries. Through detailed case study research of science-based health firms in South Africa, of the NIS health system of Ghana, and by comparing these data with data collected in Uganda and Tanzania, I shed light on these questions from an empirical perspective. I find that science-based health innovation is a complex field, and whilst institutions can help or hinder its viability, the current state of health innovation in SSA can be attributed primarily to individual entrepreneurs with strong networks, who are taking risks in a largely non-enabling environment. I find that, more important for innovation, is the ability to access global knowledge–through appropriate policies and strong partnerships–and the capacity to apply it locally. For this, tacit knowledge, or “learning-by-doing,”’ to respond to consumer demand and achieve regional product penetration, is vital. My results show that the traditional focus on knowledge - or science-heavy innovation - will simply not capture the true extent of health innovation in SSA countries. Furthermore, science-based health innovation is clearly not one thing, and it is, for example, important to understand how plant medicine innovation fit in. The aims, intentions, and impacts of African health research on the countries themselves are rather vague, which constrains innovation at all levels.
385

Science-based Health Innovation in Sub-Saharan Africa

Al-Bader, Sara 14 December 2011 (has links)
Policy making bodies are increasingly highlighting the important role innovation can play in African development─not only to spur economic growth but also to deliver locally relevant, affordable products and services to African populations. The health sector is one area where innovation is most needed; however, we know very little about the capacity of African countries to innovate in this area. At the same time, a range of conceptual questions have arisen in the academic literature as to the very definition of innovation in an African context, and specifically, the applicability of the National Innovation System (NIS) to African countries. Through detailed case study research of science-based health firms in South Africa, of the NIS health system of Ghana, and by comparing these data with data collected in Uganda and Tanzania, I shed light on these questions from an empirical perspective. I find that science-based health innovation is a complex field, and whilst institutions can help or hinder its viability, the current state of health innovation in SSA can be attributed primarily to individual entrepreneurs with strong networks, who are taking risks in a largely non-enabling environment. I find that, more important for innovation, is the ability to access global knowledge–through appropriate policies and strong partnerships–and the capacity to apply it locally. For this, tacit knowledge, or “learning-by-doing,”’ to respond to consumer demand and achieve regional product penetration, is vital. My results show that the traditional focus on knowledge - or science-heavy innovation - will simply not capture the true extent of health innovation in SSA countries. Furthermore, science-based health innovation is clearly not one thing, and it is, for example, important to understand how plant medicine innovation fit in. The aims, intentions, and impacts of African health research on the countries themselves are rather vague, which constrains innovation at all levels.
386

Use of Sweet Potato to Develop a Medium for Cultivation of Lactic Acid Bacteria

Hayek, Saeed A. 16 November 2013 (has links)
<p> This study investigated the use of sweet potatoes (<i>Ipomoea batatas </i>) as a basic component to develop a medium for cultivation of lactic acid bacteria (LAB). Extract from baked sweet potatoes was used to form a sweet potato medium (SPM). SPM was supplemented with 4 g/L of each nitrogen source (beef extract, yeast extract, and proteose peptone #3). Lactobacilli MRS was used as a control medium. Ten LAB strains were used to determine the suitability of SPM serving the growth of LAB. Our results showed no significant (<i>p</i> &lt; 0.05) differences in the optical density, maximum specific growth rates, and bacterial populations between MRS and SPM. SPM also maintained higher pH values throughout the incubation period compared to that in MRS. The cost of SPM was 47% less than the cost of MRS. Further step was taken to determine the suitability of SPM serving LAB enzymatic activity. LAB strains growing in SPM showed relatively higher &beta;-glucosidases, acid phosphatase, and phytase activities and lower &agr;-glucosidase compared to that in MRS. Strains of <i>L. reuteri</i> showed the highest enzymatic activities of &agr;-glucosidase, acid phosphatase, and phytase whereas <i> L. delbrueckii</i> subsp. <i>bulgaricus</i> showed the highest &beta;-glucosidases activity. Thus the enzymatic activity of <i>L. reuteri</i> growing in SPM was enhanced using six different metal ions. The response of <i> L. reuteri</i> strains to metal ions found to be strain dependent. The addition of Mg<sup>2+</sup> and Mn<sup>2+</sup> followed by the addition of Ca<sup>2+</sup> showed the highest enhancement effect on all tested enzymes. These findings indicated that SPM is a suitable medium serving the growth and bioactivities of LAB and thus could be used as an alternative low cost medium.</p>
387

The Gatekeeping Paradigm and the Constructivist Alternative

Sung, Kijin 22 June 2012 (has links)
Science and technology have become indispensable elements of virtually every public debate. While nations strive to employ the best experts to make timely decisions, discontented citizens increasingly demand better accountability and democratic legitimacy through broad and direct public consultation. Participatory decision-making, on the other hand, is often met by the worry that sound science might drown in a sea of ignorance. As science and technology studies (STS) attempts to navigate these conflicting concerns, it sometimes draws heavily, albeit often uncritically, upon contemporary political philosophy. In this dissertation, I explore links between H. M. Collins and Robert Evans’s account of the appropriate role of public participation in technical policy debates, and Amy Gutmann and Dennis Thompson’s liberal theory of deliberative democracy. Both views exemplify what I call the “gatekeeping paradigm”, a tendency to employ rigid constraints on admissible inputs as the primary means to direct democratic processes toward outcomes that are independently judged to be desirable. I argue that such an approach not only fails to account for the complexi-ties of public discourse in modern societies, but also reflects an impoverished conception of deliberative democracy as a black box. As an alternative to the gatekeeping paradigm, I develop and defend a social construc-tivist theory of democratic governance based on the ideas of Alan Irwin, Sheila Jasanoff, and Brian Wynne in STS; and John Dryzek in political philosophy. The constructivist view focuses less on externally imposed input-constraints and more on internal processes of self-regulation within shifting and heterogeneous discourses. Although this approach will need to be further developed and augmented with much empirical research before its efficacy can be determined, I suggest that constructivism offers a promising framework for the governance of science and technology as well as for thinking about deliberative democracy generally. / Thesis (Ph.D, Philosophy) -- Queen's University, 2012-06-21 16:54:31.171
388

Cultivating the 'generic solution' : the emergence of a Chinese product data management (PDM) software package

Wang, Mei January 2007 (has links)
This is a study of the design and development of an Organisational Software Package (OSP). It particularly focuses on the ambitions and supplier strategy of building a ‘generic software solution’ (i.e., a software system that in principle can be used by everyone). The study is located in the distinctive context provided by China, with its particular history and in a period of rapid economic reform. The starting point of this research is the apparent empirical and theoretical gap in the social study of Organisational Software Packages, in which the construction of standard solutions and the supply side of the technology's story have been largely overlooked. Moving beyond conventional information system design perspectives, this thesis draws upon concepts developed within the Social Shaping of Technology (SST) perspective, adopting an interdisciplinary approach to analyse the creation and evolution of OSPs, which enables us to address both the dynamism and continuity of these developments. In order to avoid the shortcomings of snapshot studies, we applied the concepts of ‘social learning’ and in particular the ‘biography’ of software package to examine the evolution of the OSP supply as the supplier developed its product and market strategy over a number of product cycles. Lastly, we applied Rip’s (Rip and Kemp 1998) technological transitional model to explore the influence of both the broad socio-economic context and institutional arrangements on the OSPs' development, as well as the contribution of these and related changes to changing the setting of technology. Methodologically, an extremely detailed longitudinal and contextual analysis has been undertaken through a qualitative historical case study of the evolution of a Chinese software package from 1998- 2005 in the context of China, triangulating different methods: interviewing, document analysis and participant observation. The empirical findings of this study firstly show that achieving the ‘generic’ is not an impossible goal but is rather an evolutionary process which is filled with struggles and tensions. OSP suppliers are forced to maintain a strategic balance between a range of contextual factors with technical, financial and social dimensions. Secondly, and perhaps the key contribution of this study, is the complex multi-locus and multi-layered account it offers of the OSP innovation process, according to which the supplier learns about the representation of users and use in both ‘local’ and ‘community design’ spaces with different approaches and foci through interaction with user organisations and other social players. The findings show that OSP suppliers are required to readjust their relationships with user organisations and establish cycles that move between seeking to achieve the economic imperative through standardisation and seeking to accommodate local user requirements. Thirdly, while this empirical study confirms some observations that have been made about packaged OSP production in western countries, it also reveals some specifically Chinese characters. These particular features of the development process which were identified in the Chinese PDM development were framed (using the terminology of Rip’s transitional model) by the unstable landscape and socio-technical regimes. Finally, this case study also throws light on the applicability of SST in developing countries and on the policy and practice of China’s future technology development.
389

Brain bioavailability of polyphenols| Implications for delivery of brain health benefits

Chen, Tzu-Ying 11 April 2014 (has links)
<p> Consumption of fruits and vegetables has been associated with neuroprotection and cognitive benefits throughout the life span. These associations have sparked interest in plant-derived polyphenols as biologically active agents with potential for targeting brain benefits. However, little is known regarding the ability of the polyphenols or their metabolites from polyphenol-rich products to cross the blood-brain-barrier, and be available for biological action. Furthermore, additional insight is needed on factors affecting the absorption and brain distribution of polyphenol metabolites <i>in vivo.</i> To fill gap in current knowledge, this thesis will focus on the effects of diabetogenic diet and diabetic state which have been considered potential risk factors for neurodegenerative disease on polyphenol bioavailability from a 'Standardized Grape Polyphenol' (grape seed extract, Concord grape juice and resveratrol). Additionally, this thesis will provide novel evidence on plasma pharmacokinetics and regional brain distribution of polyphenol metabolites from apple/grape seed and bilberry extracts in a weaning piglet model. </p><p> We have found that background diabetogenic diet had limited effects on polyphenol plasma levels and brain bioavailability in a healthy Sprague-Dawley rat model. However, the diabetic state negatively influenced polyphenol metabolite levels in plasma and brain tissues, possibly in part, due to excessive excretion in urine. By using a young piglet model, we determined plasma pharmacokinetics of polyphenol metabolites using physiological and pharmacological doses of apple/grape seed and bilberry extracts. We found that in a physiological dose achievable by supplementation, polyphenol metabolites were able to cross blood-brain barrier to deposit in the brain. There was a difference in regional brain deposition with cerebellum being a preferred site for accumulation. Our data warrant the future design of functional tests on aging-related diseases, specifically Alzheimer's disease as well as improvement in cognitive and memory in healthy infant/child model.</p>
390

Sensory evaluation of heart-healthy foods enriched with omega-3 fats from fish oil

Gruenfelder, Catherine A. 11 June 2014 (has links)
<p> A diet rich in omega-3 fats has been shown to reduce the risk of cardiovascular disease. Long chain omega-3 fats found in fatty fish are especially important to cardiovascular health. Consumption of these fats is low, in part because there are few natural sources. This has led to the development of omega-3 fortified foods. Currently available fortified foods demonstrate conflicting nutritional information. Addition of omega-3 fats to an otherwise unhealthy food is perceived by consumers as an advertising gimmick. Mistrust of food companies and confusing ingredient labels negatively impact sales. Careful nutritional guidance, combined with proper sensory analysis, is critical to developing omega-3 fortified food products that are consistent with medical recommendations. Results from this study indicate that a therapeutic dose of fish oil (1000 mg per serving) can be added to two heart-healthy foods without adversely affecting sensory qualities.</p>

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