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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.
741

A Study of Industrial Arts Woodworking Housing and Equipment Facilities in Texas

Mabry, Steve N. 08 1900 (has links)
This is a study comparing the existing industrial arts housing and equipment facilities in the state of Texas with: first, housing standards within ad tentative Texas Education Agency publication entitled A Guide for Planning Industrial Arts Facilities; and second, apparent equipment needs for implementing the programs described in Texas Education Agency Bulletin 615, Principles and Standards for Accrediting Elementary and Secondary Schools and Description of Approved Courses Grades 7-12.
742

Studies of cell population kinetics in the hamster cheek pouch, with reference to the difference in growth between normal and malignant cells

Reiskin, Allan B. January 1966 (has links)
No description available.
743

A Study of Corrosion Monitoring Techniques Used in URLs for Metals

Li, Sirui 23 March 2017 (has links)
With the increasing use of fission-type nuclear power generation, particularly high-levels radioactive nuclear waste are generated, so the safe use of nuclear energy requires proper disposal of high-level radioactive nuclear waste. The selected treatment method is deep geological disposal. Therefore, underground research laboratory (URL) to prepare for deep geological disposal will also be carried out. Corrosion of metallic materials, which are closely related to the safety of URL, is the focus of this research project. This study selected monitoring techniques for URL and developed a rough monitoring scheme for temperature and resistivity in URL. In this study, corrosion-temperature and corrosion-resistivity monitoring experiments were carried out in different bentonite samples to simulate the experiments in URL. The results show that the self-compensating high-precision inductance corrosion monitoring system and multifunction soil corrosion rate measurer proved to be a good system for monitoring the corrosion-temperature and corrosion-resistivity of metals. However, the life span limitation makes them unable to meet the requirements of URL. The results also show that the corrosion rate of metal in bentonite is positively correlated with temperature. The existing electrochemical probes are suitable for monitoring the corrosion rate, but not suitable for soil corrosion rate monitoring.
744

The effects of melatonin on the testis, epididymis and sperm physiology of the Wistar rat

Gwayi, Noluzuko January 2001 (has links)
Melatonin is a product of the pineal gland and is postulated to play an antigonadotropic role in the reproductive system of mammals. The reproductive system of non-seasonally breeding mammals is believed to be not as responsive to melatonin treatment as that of seasonally breeding mammals. Recently, there has been increasing support from in vivo and in vitro studies, for the hypothesis that melatonin has negative effects on sperm physiology, especially on sperm motility. High and/or low seminal concentrations of melatonin have been associated with abnormalities in human sperm motility and concentration. In this study, I examined the effects of melatonin on the testis, epididymis and sperm physiology, using in vivo and in vitro experiments, in a non-seasonally breeding mammal. Treatment, in vivo, with exogenous melatonin for six weeks did not inhibit testosterone production or spermatogenesis, nor did it affect the mass of the testes and epididymides at dissection, the concentration the morphology of speimatozoa. However, melatonin in vivo had a small, but significant negative effect on sperm motility and sperm motility index. In vitro incubation of spermatozoa Fith melatonin reduced the percentage (%) of forward progressive movement (fpm), increased the % reduction in fpm, reduced the vigor or quality of sperm motility, reduced the sperm motility index, and delayed and/or prolonged the transition of one pattern of sperm motility to the subsequent patterns. Melatonin increased the pH of the culture medium, and the increased pH, and the ethanol utilized as a solvent for melatonin, both negatively affected all the sperm motility parameters that were assessed in my study. The effects of ethanol increased with time, and the effects of pH increased with both time and increasing pH. Melatonin in vitro did not inhibit capacitation and the acrosome reaction, but it delayed the onset and the progression of capacitation and the acrosome reaction. These results suggest that while melatonin did not inhibit spermatogenesis in the Wistar rat, it may influence sperm motility. Therefore, the presence of high concentrations of melatonin in the reproductive fluids may inhibit sperm motility. With further detailed research, melatonin may have a potential use as a contraceptive drug.
745

Evidence for the alternative pathway of complement activation in the nurse shark

Culbreath, Lieneke Cecile 25 November 1992 (has links)
Complement is activated via two pathways: classical (CCP) and alternative (ACP). The CCP has been demonstrated in the nurse shark. The ACP has not been demonstrated in any cartilagenous fish. Nurse shark serum was evaluated for complement activity by its ability to lyse heterologous erythrocytes. As CCP activity requires calcium and magnesium, activity of shark serum chelated with EGTA (a selective calcium chelator) or EDTA (a chelator of calcium and magnesium) was assessed. Activity remained in serum chelated with EGTA but not EDTA. Furthermore, activity of chelated serum was enhanced by added magnesium. Activation of shark complement by activators of mammalian ACP (zymosan, LPS, inulin, CVF) was assessed. Complement was activated by zymosan and LPS. Immunoblots were employed, with limited success, to demonstrate complement proteins in nurse shark serum. This study unequivocally demonstrates that the ACP is present in the primitive nurse shark.
746

Observed pathological changes in male Wistar rats after co-treatment of Type II Diabetes with metformin and sutherlandia frutescens

Tili, Siphokazi Pamphilia January 2012 (has links)
Diabetes is a serious condition that affects all the body’s systems including kidneys, heart, eyes and limbs. This alone makes type II diabetes a life threatening disease; an expensive disease and economic burden that many individuals struggle to cope with.The rapid growth type II diabetes in South Africa is associated with the change of life style, and environmental factors brought by westernized way of life living in rural areas. Despite the technical advances in diagnosis and therapy of diabetes many people still use alternative forms of therapy due to the cost, traditional reasons and religion. Some of the people use the conventional medication together with the alternative therapy without informing their doctor and knowing the pathological changes. The aim of the study was to investigate pathological changes in male Wistar rats after co-treatment of type II diabetes with metformin and Sutherlandia frutescens and the possible synergistic and antagonistic effects. The thirty five rats were divided into five groups, seven in each group. There were two control groups and three test groups. Only the first control group was on a low fat diet (normal rat pellets) and second control group and test groups were on a high fat diet which induces obesity, insulin resistance and leads a typical prediabetic state for 12 weeks (Buettner et al., 2006). After 11.5 weeks medication was administered by oral gavaging to the test groups for 4 weeks and control groups received water. Blood was collected for determination of glucose, insulin, lipid profile and the concentrations of the liver enzymes. Pancreas, liver and kidney tissue were removed and used for histology. Urine was collected from the bladder for creatinine analyses. The plant + metformin group co-treatment was better in managing hyperglycemia, liver damages were minimal and also weight control was better when compared to metformin alone.
747

The pig as a biomedical model to study human protein calorie malnutrition

Thacker, Philip Alfred January 1978 (has links)
Two experiments were undertaken to evaluate the baby pig as a biomedical model with which to study Protein-Calorie malnutrition. In the first experiment, 32Yorkshire and Yorkshire X Landrace pigs weaned at 21 days were fed either an 18% or 4% protein ration. Blood samples were taken biweekly from the anterior vena cava and the serum samples analyzed for calcium, phosphorus, glucose, cholesterol, lactic dehydrogenase, glutamic oxaloacetic transaminase, amylase, a 1ka1ine phosphatase, total protein, albumin and blood urea nitrogen. Significant (p ≤.01) treatment effects were observed for total protein, albumin, amylase, alkaline phosphatase, lactic dehydrogenase, cholesterol, calcium and phosphorus. In the second experiment, 40 Yorkshire and Yorkshire X Landrace pigs weaned at 28 days were fed rations containing 18%, 10%, 8%, 6%, and 4% protein. Blood samples were again taken biweekly and serum samples were analyzed for the same parameters as in trial one. In addition, serum copper, iron, magnesium, and zinc were measured. The livers of any animals which died on the low protein diets, were fat extracted, and the level of fat compared to that obtained from livers of animals killed as suckling pigs at a slaughter plant. Total body water was determined on three animals on the 18% ration and three on the h% ration utilizing tritiated water as a tracer. Total protein, albumin, amylase, lactic dehydrogenase, calcium, phosphorus, copper, iron and magnesium correlated well with dietary protein intake. Significant treatment effects were observed for total body water and fat content of the liver. An attempt was made to find a biochemical parameter which might be used in diagnosing developing protein calorie malnutrition. The results of the study would indicate that serum phosphate and amylase are the most sensitive parameters to dietary protein intake. Not every lesion or biochemical serum change occurring in man was reproduced in the present study. Nevertheless, characteristic symptoms such as the development of fatty liver, growth retardation, abnormal hair texture, hypoalbuminemia, and apathy were reproduced in the protein deficient swine. The baby pig would therefore appear to be a good model for the study of protein-calorie malnutrition. / Land and Food Systems, Faculty of / Graduate
748

Evaluation and standardisation of laboratory methods used for determining the degree of soya processing

Modika, Kedibone Yvonne 28 June 2011 (has links)
The use of full fat soybeans (FFSB) in animal feeds has, to date, been limited due to the presence of anti-nutritional factors (ANF). It is, therefore, increasingly recognized that, if the full potential of full fat soybeans for the use in diets is to be realized, reliable analytical procedures must be available for the quality control of processed FFSB which would enable feed manufactures to determine the degree of soybean processing. Results of currently available analytical techniques vary widely between laboratories, causing uncertainty and confusion among soybean processors, feed manufacturers and end users. A collaborative study was conducted to standardize a number of existing analytical procedures used for determining the effects of heat treatment on FFSB and to generate South African ranges for standardized laboratory procedures. Raw soybeans, in a mixture of cultivars, were processed by dry extrusion at eight different temperatures (110ºC, 120ºC, 127ºC, 136ºC, 140ºC, 145ºC, 151ºC and 164ºC). In vivo trials were conducted on broiler chicks which were fed the eight extruded FFBB. Their performance was monitored with regard to average daily gain (ADG) and feed conversion ratio (FCR). The Protein Solubility in KOH (PSKOH) and the Protein Dispersibility index (PDI) procedures were used for standardization in an inter-laboratory study with the participation of ten South African analytical laboratories. Statistical analysis of the in vivo trials with broilers showed no significant difference (P>0.05) between broilers fed FFSB processed at 136 ºC, 140 ºC and 145 ºC. In addition, samples processed at those temperatures (136 ºC, 140 ºC and 145 ºC) showed the best chick performance with regard to average daily gain (ADG) and the feed conversion ratio (FCR). There was a significant difference (P<0.05) between broilers fed FFSB processed at 110 ºC, 120 ºC and 120 ºC as well as those fed FFSB processed at 151 ºC and 164 ºC. In vitro results showed that the PSKOH and PDI values corresponding to temperatures which showed the best chicken performance were between 67-77% and 10.3-8.5 index units respectively. Therefore, the South African ranges for describing the degree of soybean processing using the PSKOH method are 66-77% with repeatability and reproducibility limits of 3.5 and 10.9 respectively and, when using the PDI method, are 8.5-10.3 index units with repeatability and reproducibility limits of 2.1 and 7.7 respectively. A very good correlation was established between the animal production parameters and the PSKOH values, while a poor correlation between animal production parameters (ADWG and FCR) and PDI values was established. The PSKOH method was found to be the most reliable method for FFSB quality control under standardized South African conditions. / Dissertation (MSc)--University of Pretoria, 2011. / Animal and Wildlife Sciences / unrestricted
749

Connectivity : an urban laundry in the Pretoria CBD

Wright, Louis Gerhard 30 July 2008 (has links)
Overall goal: “The overarching aim of the Programme is to promote a sense of dignity in the public real, targeting the poorest and most disadvantaged parts of the city, by providing each local area with a place where individual circumstances of poverty are not starkly visible, where people can meet and gather or just sit in a place that is as attractive and comfortable as any other well-made, positive place in the city.” [Southworth, 2003:125] Problem identification: The form and structure of the city is driven by the urban legend that almost all users will move through the city by car, bus or taxi. This produced a low-density, disorganized expansion which forces users to commute between spread out facilities. Public space in the city has largely been neglected, with green areas fenced of [e.g. the Union buildings green space] and existing squares and arcades taken over by commercial interests. The perception is created that these vital areas are extravagant squander of money both to create and maintain. This resulted in neglected and derelict spaces scattered around the city, often only used as parking. The focus of designers has largely been on individual buildings only, neglecting their impact on their neighbours, the street and their interaction on public space. Project aims and objectives: Explore and analyse the interconnected systems inherent in the city. In order to obtain a comprehensive understanding of some of the systems and processes that are active in the city, analysis needs to be done on several levels.Regional scale: The city systems as part of the larger Tswane Megacity. City scale: Explore the interaction of these processes within the CBD. Local scale: Placing the study area within the north-eastern quarter of the CBD to create a master program for the area. Create a master program for the north-eastern quarter of the city incorporating these systems and processes. Study the workings of the north-eastern quarter to develop guidelines for its improvement. Place an urban catalyst within the study area to promote regeneration on social, economic and urban levels. Design an architectural response to the new urban catalyst. Approach: The creation of a public space, linking isolated city blocks. To use buildings to fill gaps in the existing street edges, as well as defining the new public space. This will lead to economic and social regeneration of the area. Develop guidelines for function selection of building linked to the street and public space. Design an architectural response to the new public space. / Dissertation (MArch(Prof))--University of Pretoria, 2008. / Architecture / unrestricted
750

Sistemática de ações de segurança e saúde no trabalho para laboratórios de pesquisa com atividades de nanotecnologia

Andrade, Luis Renato Balbão January 2013 (has links)
As nanotecnologias são um conjunto multidisciplinar de técnicas que manipulam a matéria em escala nanométrica, mais precisamente partículas abaixo de 100 nanômetros, cujas características por conta do tamanho diminuto são essencialmente diferentes daquelas encontradas no material em sua forma macro. Em função destas novas propriedades dos materiais, existem lacunas de conhecimento relativas aos efeitos destas partículas sobre o organismo humano e sobre o meio ambiente. Embora ainda sejam consideradas tecnologias emergentes, seu crescimento é cada vez mais acelerado e o número de produtos que fazem uso de nanotecnologia em alguma fase de sua produção continua crescendo, bem como o número de pesquisadores envolvidos com o tema. Considerando este cenário e a literatura pertinente, este trabalho objetivou desenvolver uma sistemática de ações de segurança e saúde no trabalho (SST) para laboratórios de pesquisa com atividades de nanotecnologia. Esta sistemática é fundamentada na estrutura das diretrizes para um sistema de gestão de segurança e saúde no trabalho proposto pela Organização Internacional do Trabalho (OIT). A esta base foram agregadas diversas recomendações nanoespecíficas, sendo desta maneira consolidada a Sistemática de SST para Laboratórios com Nanotecnologia (S-SST/LabNano). Além da comparação desta sistemática com outras apresentadas por outros autores, uma pesquisa survey foi realizada, com o propósito de obter um retrato da SST em laboratórios com atividades de nanotecnologia no Brasil. De forma complementar, objetivando a adequação prática, a S-SST/LabNano foi avaliada em relação a realidade de SST encontrada em laboratório. O resultado final da tese, além da sistemática em si (S-SST/LabNano), almeja oferecer elementos de reflexão que possam auxiliar a gestão e o controle de riscos ocupacionais associados às nanotecnologias. / Nanotechnology is a multidisciplinary set of techniques that manipulates material at nanoscale, precisely particles below 100 nanometers whose characteristics, due to the small size, are essentially different from those found in material while in macro format. In the light of these new properties of materials, there are knowledge gaps regarding the effects of these particles on the human body and the environment. Although still considered emerging technologies, their growth is increasingly accelerated and the number of products that use nanotechnology in some stage of its production continues to grow, as well as the number of researchers involved with the topic. Given this scenario and its relevant literature, this study aimed to develop a proposed methodology of actions in occupational safety and health (OSH) to research laboratories with nanotechnology activities. This methodology is based on the structure of the International Labour Organization (ILO) guidelines for a management system in safety and health at work. Several specific recommendations were added, named Participatory Nano Safety Lab (PNSL). Besides the confrontation of this proposal with other authors, a research survey was conducted with the purpose to obtain a general picture of the OSH in laboratories with nanotechnology activities in Brazil. In a complementary way, aiming a practical suitability, the PNSL was confronted with the reality of OSH found in laboratory. The final result of this thesis, besides the methodology itself (PNSL), aims to provide elements of reflection that may assist management and occupational risk control associated to nanotechnology.

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