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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.
81

EVALUATION OF THE PHYSIOLOGICAL EFFECTS OF REDUCED HYDROXOCOBALAMIN ON ACUTE CARBON MONOXIDE TOXICITY

Newcomb, Alden 01 January 2014 (has links)
Carbon monoxide (CO) poisoning represents a global health threat responsible for hundreds of thousands of hospital visits and tens of thousands of deaths annually. Oxygen therapy is the only current approved treatment for CO poisoning. Previous work published in the 1970’s and research conducted in the VCURES lab group has indicated that a reduced form of vitamin B12, hydroxocobalamin (B12r), can potentially serve as an antidote for CO poisoning by converting CO bound to hemoglobin to carbon dioxide (CO2) and mitigating the deleterious neurological effects of CO poisoning. For the first time in documented literature we successfully used a Clark-type polarographic oxygen-sensitive electrode to demonstrate CO-induced decreases in brain tissue oxygen tension in anesthetized rats. Additionally, we demonstrated that B12r is capable of rescuing this CO-induced hypoxia and hypotension within 15 minutes of intraperitoneal administration with no adverse effects on blood chemistry.
82

Studies on microbiological hazards associated with ethnic foods, with particular reference to mycotoxin formation and clostridium perfringens

Pearson, Susan M. January 2000 (has links)
No description available.
83

The deactivation of silico-aluminophosphate catalysts during methanol conversion reactions

Cornel, Veronica May January 1993 (has links)
A dissertation submitted to the Faculty of Science, University of the Wtlwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science / This dissertation focusses on the deactivation of SAP0-34 and modified SAPOs during methanol conversion under various conditions, in comparison to H-ZSM-5. SAPO-34 was found to deactivate rapidly during methanol conversdon. This was shown by the decrease in activity, surface area and pore volume of the catalyst. The deposited "coke" was analysed by in situ diffuse reflectance infra-red Fourier Transform spectroscopy,solid-state magic angle spinning nuclear magnetic resonance, gas chromatography mass spectroscopy (GCMS) of the HF- and dichloromethane-extracted to "coke"; and GCMS of the organic specfes released during regeneration of the catalyst and trapped in resin capillary inlet tubes.The "coke" consisted of alkylated aromatics and naphthalenes which probably formed on the surface or in the large cavities of SAPO-34. The amount of "coke" deposited during methanol conversion increased with reaction temperature, decreased with dilution of the methanol with water or nitrogen. and decreased with increased pressure, Incorporation of Ni into the SAPO framework did not decrease the rate of deactivation, but the "coke" that Has deposited was less bulky than that deposited in SAPO-34. Modification of the SAPO-34 with trlmethyl silylchloride decreased the rate at deactivation of the catalyst. / AC 2018
84

Characterisation of Listeria monocytogenes using targeted proteomic analysis

Bishop Simon, Shurene Patrice January 2012 (has links)
Listeria monocytogenes is the causative agent of listeriosis, a severe foodborne infection that is increasing significantly in Europe and North America. A correlating factor contributing to the resurgence of listeriosis is the rise in consumption of cold-stored ready-to-eat (RTE) foods. The steady upsurge in disease requires more focused research to control the pathogen, L. monocytogenes. Currently, there is a plethora of diagnostic methods for the causative agent, however, each has limitations, one of which is the inability to correlate results across laboratories. This is a particular hindrance to an outbreak investigation in an age when food is transported widely across the globe. In this study, proteomic approaches were used to search for biomarkers that facilitate rapid characterisation of isolates against a background of differentially expressed proteins. A preamble to this investigation necessitated incorporation of an efficient lysis procedure to release maximum proteins. This was eventually achieved using a Listeria specific enzyme, endolysin, and a disruptive mechanical method. Liquid Chromatography-Mass Spectrometry/Mass Spectrometry (LC-MS/MS) data showed that bead beating and enzymatic lysis were the most efficient methods for analysis of the proteome. Dendrogram lineages, derived from MALD-TOF-MS spectra, strongly correlated with 16S rRNA analyses. Selective protein capture and analysis by MALD-TOF-MS (designated SELDI-TOF-MS) demonstrated considerable intraspecies diversity as revealed by dendrograms which were also visualised by „Heat Maps‟. One-dimensional polyacrylamide gel electrophoresis and LC-MS/MS analysis of seven L. monocytogenes isolates, led to the successful identification of two proteins; a hypothetical protein, designated lwe06778 and a phosphoribosyl-AMP cyclohydrolase which were uniquely present at 4°C. This finding suggests that L. monocytogenes depends on the histidine biosynthesis pathway in order to survive at cold temperatures. It is hypothesised that the addition of inhibitors, specific to both proteins in RTE cold foods may be a useful means for controlling outbreaks of listeriosis in the future.
85

The Role of Auditory Attentional Processing and Attentional Behaviour in Accounting for Deficits in Cognitive Abilities of Children Exposed to Environmental Lead

Roberts, Russell James, r.roberts@griffith.edu.au January 2003 (has links)
The effects of lead poisoning have been known for centuries and the deleterious effects of chronic, low to moderate levels of lead exposure on children's cognitive functioning is now well-established (Needleman & Gatsonis, 1990; Schwartz, 1995). Similarly, low and moderate levels of lead exposure early in life have been frequently associated with behavioural disturbances later in life in children and animals. However, few studies have systematically investigated the link between lead-induced deficits in cognitive functioning and lead-induced behavioural disturbances. This project describes a series of studies investigating the effects of lead on auditory processing and attentional behaviour, and their ability to account for the deleterious effects of lead on IQ in children participating in the Port Pirie Cohort study. Capillary blood samples were collected from the children at various ages from birth to 2 years, and annually thereafter until the age of 7. A measure of lifetime PbB was calculated for each child using the geometric mean of all the blood lead samples. This measure of lifetime PbB was used as a continuous explanatory variable in each of the studies described below. A variety of sociodemographic, health, anthropometric, birth and developmental covariates and potential confounders were recorded prospectively and concurrently. Using Needleman et al.'s (1996) analysis protocol, 8 of these covariates were included in all final regression models. Study One: A total of 387 children from Port Pirie, Australia (mean age of 7.7 years) participated in a study of children’s simple auditory processing. Children completed a series of monaural listening tasks across 4 ear/hand conditions. It was hypothesised that auditory reaction time and auditory processing accuracy would be related the lifetime PbB. Analysis revealed no significant associations between lifetime PbB and the reaction time to target words and a small significant association (3.6%) between lifetime PbB and accuracy of target word detection in just one of the four ear/hand conditions. The strongest associations were found between PbB and false responses to distractor words (10.1%, after adjusting for confounders). It was speculated that this pattern of results could be explained via lead effects on other processes such as impairments to impulse control or attentional processes. Study Two: Study Two investigated the effect of lifetime PbB on children’s complex auditory processing. In this study participants completed dichotic listening tasks across 4 different ear/hand conditions. After controlling for potential confounders, lifetime PbB accounted for 6.2% of the variance in the accuracy of target word detection. A weak direct association (3.0% of the adjusted variance) was also found between lifetime PbB and target word reaction time. No significant associations were found between lifetime PbB and the percentage of false responses or the speed of the false responses. Again the pattern of results was suggestive of a deficit in attentional processes such as freedom from distraction and impulse control. Study Three: This study hypothesised that lead-induced impairments to attentional behaviour - similar to those observed in Studies One and Two - would be observed in other contexts. The mothers of 492 cohort children, and teachers of 454 of the children participated in this study. The mean age of children for whom ratings were collected was 7 years and 4 months. Two versions of the Conner’s Behavior Rating Scale were used to rate the children’s behaviour: The Parent Rating Scale and the Teacher Rating Scale. Lifetime PbB accounted for a significant amount of the variance in Conner’s Parent Behavior Rating Scale scores. It accounted for 5.9% and 7.3% of the unadjusted variance in the Immature/Inattentive, and Hyperactive/Impulsive scores respectively. After adjusting for covariates, each of these associations remained significant. The associations between lifetime PbB and girls' behaviour scores were much higher (11.2%) than the PbB associations with boys' behaviour scores (4.6%). The unadjusted associations between lifetime PbB and Teacher Rating Scores, although much lower, were also significant and accounted for between 1.2% and 2.4% of the variance in the behaviour scores. However, after controlling for potential covariates these associations were no longer significant. These results indicated that increases in lifetime PbB were associated with higher Hyperactivity/Impulsivity and Immature/Inattention and scores on the Conner's Parent Rating Scale, but not the Conner's Teachers Rating Scale. Study Four: In this study it was hypothesised that a significant association would exist between children’s auditory processing performance and parent and teacher behavioural ratings of inattention and impulsivity. Correlational analysis was conducted on the data from Studies One, Two, and Three, to ascertain if the behavioural patterns as reported by the children's parents and teachers, were associated with the children's performance on the auditory processing tasks. Correlational analysis revealed highly significant correlation coefficients in the direction predicted between auditory processing scores and the Inattention and Hyperactivity/Impulsive scores of the Conner's Parent and Teacher Rating Scales. Study Five: The purpose of this study was to examine the extent to which auditory processing and attentional behaviour scores could account for the lead-induced deficits in children's global cognitive abilities. Combining IQ data with data from Studies One, Two, and Three, a hierarchical analysis was conducted with lifetime PbB as the continuous explanatory variable. The analysis entered potential covariates at step 1, behaviour ratings at step 2, auditory processing efficiency in step 3, auditory processing speed in step 4, and lifetime PbB at step 5. The results indicated that when parent and teacher ratings of behaviour and auditory processing efficiency were included in the model, lifetime PbB no longer accounted for a significant proportion of Verbal, Performance or Full-Scale IQ scores. On the other hand, further analyses demonstrated that the significant associations between lifetime PbB and parental behaviour ratings could not be accounted for by including IQ scores as mediating variables in the analytical model. Conclusion: The results of this project provide evidence for the deleterious effect of lead exposure on children's auditory processing performance and parent ratings of behaviour. Further, including these variables in an analysis of the effects of lifetime PbB on IQ served to markedly attenuate direct effect of lead on IQ to the level of non-significance. Taken together the data implicates disturbances to attentional processes (such as impulsivity and inattention) as possible mediators of lead-induced deficits in IQ.
86

Identification of OCT-2 as a mediator of lead neurotoxicity /

Bakheet, Saleh Abdulrahman. January 2005 (has links)
Thesis (Ph. D.)--University of Rhode Island, 2005. / Typescript. Includes bibliographical references (leaves 120-131).
87

Livsmedelsäkerhet i förskolan : Vilka rutiner har förskolan och finns det skillnad i livsmedelsäkerheten beroende på personalens utbildning

Öberg, Erika January 2015 (has links)
The aim of the study was to investigate which routines preschools had regarding food processing and if the routines were sufficient in order to the regulation. The aim was also to investigate if there were some difference in food processing depending on the employee´s education. The method used was an interview study of 20 preschools. The results indicated that the majority of the preschools had sufficient routines regarding temperature control of hot and cold lunches. Regarding measurement on deviant temperature, half of the preschools routines were sufficient. 55 % of the preschools had insufficient routines for temperature control in cold storage. Results indicate that it was differences in how often the employee´s control the temperature in food depended on the employee´s education. The conclusion is that a number of preschools had a capacity for improvement of their routines. The preschools have to work with prevention measures to create routines which is sufficient in order to the regulation.
88

Halogeton: A Stock-Poisoning Weed

Armer, Walter 05 1900 (has links)
This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.
89

Sudangrass Hay Production in the Irrigated Deserts of Arizona and California

Knowles, Tim C., Ottman, Michael J. 05 1900 (has links)
Originally Published: 1997; Revised / 5 pp. / Foreign sudangrass hay buyers want dust-free hay with a bleached light green color and a stem diameter less than one quarter of an inch. Two types of sudangrass hybrids are currently grown in the United States: true sudangrass hybrids and sorghum-sudan hybrids. Sudangrass and related hybrids are annual warm season grasses grown for pasture, green chop, silage, and hay. Sudangrass produces well on all soil types, however best yields are obtained on well-drained, deep loam soils that have a high capacity to absorb and hold water. Sufficient nitrogen should be applied at planting to ensure establishment of the crop and hasten development. Typically, 40 to 80 pounds of actual nitrogen per acre are suggested at planting, based on results from a preplant nitrate-nitrogen soil test. This should be followed by split applications of 60 to 120 pounds actual nitrogen per acre in irrigation water following each cutting. Harvest sudangrass when it is at least 18 to 24 inches tall at the first cutting. Nitrates present in hay crops are considered toxic to many classes of livestock. Most cases of hydrocyanic or prussic acid poisoning are caused by the ingestion of plants that contain cyanogenetic glucosides. Cyanogenetic glucoside itself is non-toxic but hydrocyanic acid.
90

Campus Network Design and Man-In-The-Middle Attack

Nazari, Mahmood, Zhou, Kun January 2014 (has links)
Security is at the front line of most networks, and most companies apply an exclusive security policy enclosing many of the Open Systems Interconnection (OSI) layers, from application layer all the way down to Internet Protocol (IP) security. On the other hand, an area that is often not protected with high level of security is the second layer of OSI model and this can compromise the entire network to a diversity of attacks.This report presents an experimental performance analysis within the real environment. It focuses on understanding and preventing the Man-In-The-Middle (MITM) also known as Address Resolution Protocol (ARP) Poisoning on the Cisco Catalyst 3560 series switches with Cisco IOS Software. The Linux Command Line (CLI) tools and Ettercap tool were used to launch the Layer 2 attacks that you might come up against. Mitigation methods to stop this attack are evaluated and concluded. Finally we will answer if Secure Socket Layer (SSL) is enough to protect the users’ data against MITM in the network.A HP laptop and two DELL PCs were utilized for these tests and acted as the attacker, the Server and the victim. Victim PC runs Windows 7, attacker’s Laptop and server run Linux.Finally, three different case studies were analyzed and compared with each other and different solutions that might help to solve or detect the issue of MITM attack are concluded.

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