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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.
1

Artemisinin-Based Combination Therapy (ACTs) Drug Resistance Trends in <em>Plasmodium falciparum</em> Isolates in Southeast Asia

Schilke, Jessica L 10 April 2009 (has links)
Plasmodium falciparum, one of the parasites that cause clinical malaria, is a continuous public health concern, especially in Asia and Africa. Unfortunately, the parasite has developed resistance to many drugs created to treat and prevent the disease. Artemisinin and its derivatives are the new gold standard for treatment of malaria, yet treatment failures in clinical studies are starting to be reported. Clearly, artemisinin resistance needs to be characterized and dealt with accordingly. In support of the Gates Foundation Artemisinin Consortium, we conducted a blinded study to elucidate the phenotypic response of artemisinin derivatives of parasites derived from patient blood samples from Cambodia and Thailand. Blood samples containing Plasmodium falciparum were cultured and then assayed using SYBR green as an indicator to obtain drug IC50s. The data suggested that many isolates are not demonstrating resistance to artemisinin. However, a select few are showing some resistant characteristics in the form of elevated IC 50s, especially to some of the drugs already identified in previous studies as drugs having resistant characteristics. Compared to studies conducted within the past ten years, no significant changes in parasite susceptibility to the artemisinin drugs have been observed. Additional analysis of clinical outcomes, therapeutic drug levels, and molecular markers needs to be completed before it can be assumed that artemisinin resistance has emerged.
2

Comparison of real-time PCR assays for screening of meticillin-resistant Staphylococcus aureus

Sharif, Sanaz January 2011 (has links)
Staphylococcus aureus belongs to the normal flora. Many healthy people are colonized by the bacterium mainly in the nose but also on the skin and on other mucous membranes without showing symptoms. After damage to the skin, the bacterium can enter the wound and cause infections. Methicillin-resistant S. aureus (MRSA) is resistant to b-lactam antibiotics such as penicillin and methicillin. The gene that gives resistance characteristic of MRSA is the mecA-gene. MRSA strains are spread in both hospitals and in the community, and it is important to identify these bacteria with rapid and sensitive methods. In this study, Taq Man RT-qPCR was compared with SYBR Green RT-qPCR (LightCycler480, Roche) to explore which method had the best sensitivity with the least working hours. In addition, Bullet for automated DNA extraction and CAS 1200 ™ for automated pipetting of the samples were evaluated. Twelve patient isolates and 232 patient samples for MRSA screening were included in the study. The results showed that the primers were of major importance for the outcome of the amplification. It was also shown that the Ct-values were clearly lower when the Bullet, CAS 1200 ™ and LightCycler480 were combined compared with manual DNA extraction, manual pipetting and the Rotor-Gene 6000. In future, the former method will be used by the laboratory when screening patient samples for MRSA.
3

Detection of Honey Bee Viruses in Apis mellifera and Apis cerana

Lindström, Malin January 2011 (has links)
Two species of bees in the genus Apis, real honey bees, has long been of interest for man. These two are the European honey bee, Apis mellifera, and the Asian honey bee, Apis cerana. In Vietnam, beekeeping is of great importance, both with A.cerana and A.mellifera. The aim of this project was to investigate if the introduction of the European honey bee in Asia has affected the Asian honey bee, and whether different pathogens from A.mellifera have been transferred to A.cerana. Totally 40 samples, 20 from every species, were analysed for 8 different viruses. RNA was extracted and analysed with qRT-PCR. The results showed that 5 different viruses were present in the samples, DWV, CBPV, BQCV, SPV and SBV. SPV and SBV were only found occasionally while DWV, CBPV and BQCV were present in the majority of the samples. Differences in virus titres between the two bee species were significant for CBPV and BQCV, however the result for DWV titres was not considered significant. DWV therefore seem to be a ubiquitous virus in Vietnamese beekeeping irrespective of species. Further, the results cannot describe the influence or origin of the viruses but only confirm their presence. Additional investigations are needed in order to answer this question.
4

Permeability of POPC bilayer by dirhodium complexes

Sears, Randy Bryan 10 December 2007 (has links)
No description available.
5

Tidsserieanalys av aktiv norovirus-infektion med RT-qPCR / Time-series analysis of active norovirus-infection with RT-qPCR

Dahlin, Henrik January 2019 (has links)
Norovirus som orsakar vinterkräksjukan är en av de vanligaste vintersjukdomarna i Sverige. Sjukdomstiden varar generellt i en till tre dagar med symptomen kräkning och/eller diarré. Till den totala sjukdomsbilden världen över gällande akut gastroenterit, bidrar norovirus med 18 %. Trots att sjukdomen är mycket vanlig är kunskapen om norovirusets förfarande till stor del okänd.Syftet med studien var att göra en tidsserieanalys, även så kallad One-Step Growth analys, av koncentrationen minus-RNA i celler som infekterats med olika koncentrationer av murint norovirus (MNV). För att detektera minus-RNA användes RT-qPCR med SYBR Green. Målet var att se om startkoncentrationerna av virus vid någon tidpunkt korrelerar med mängden minus-RNA i cellerna. Efter 4 och 8 timmar fanns ett exponentiellt samband mellan den initiala viruskoncentrationen och minus-RNA-uttrycket i cellerna. Koncentrationen minus-RNA i de infekterade cellerna ökade mellan de undersökta tiderna 4, 8 och 24 timmar. Vidare visade resultaten att det krävs 4 timmar för att minus-RNA skulle vara kvantifierbar vid en högre infektionskoncentration av viruspartiklar, medan det krävs 24 timmar för den lägre infektionskoncentrationen av viruspartiklar. / Norovirus causes winter vomiting disease and is one of the commonest cause of winter illness in Sweden. The disease period generally lasts one to three days with symptoms like vomiting and/or diarrhea. To the disease burden of acute gastroenteritis worldwide, norovirus contributes with 18 %. Even though the illness is very common, the knowledge about norovirus is poor and largely unknown.The purpose of the study was to do a time series analysis, a so-called One-Step Growth analysis, of the minus-RNA concentration in cells infected with different concentrations of murine norovirus (MNV). For the detection of minus-RNA RT-qPCR was used with SYBR Green. The goal was to correlate start concentration of virus at any time with the amount of minus-RNA in the cells. At 4 and 8 hours there was an exponential connection by the initial virus concentration and minus-RNA development in the cells. The concentration of minus-RNA in the infected cells increased between 4, 8 and 24 hours. Further, the results can be interpreted as requiring 4 hours for the higher concentrations to become quantifiable, while requiring 24 hours for the lower concentrations to become quantifiable.
6

CORRELATION BETWEEN ENDOMETRIAL MARKERS AND PREGNANCYOUTCOME IN WOMEN WITH UNEXPLAINED INFERTILITY

Runesson, Liselotte January 2010 (has links)
<p>ABSTRACT</p><p>A defect implantation process is the major reason for unexplained infertility. Estrogen andprogesterone are steroid hormones preparing the endometrium for implantation. They mediatetheir effect through their receptors: estrogen receptor alpha and beta and progesteronereceptor A and B, respectively. Leukemia inhibitory factor (LIF), which is also important forimplantation, mediates its effect through LIF receptor and the coreceptor, gp130, and is downregulated by suppressors of cytokine signaling 1. The aim of the study was to compare thelevels of the steroid hormone receptors and LIF related factors in the endometrium of twogroups of women with the diagnosis unexplained infertility: one that became pregnant afterassisted reproduction and one that did not become pregnant. Before treatment of thesewomen, endometrial mRNA was collected during the window of implantation in themenstrual cycle. The levels of specific mRNAs were measured with real-time PCR. Womenwho had become pregnant had a significantly higher level of steroid hormone receptors. Thus,these proteins seem to be important for a pregnancy and may be suitable as receptivitymarkers.</p>
7

Extraction, concentration and detection of metallic pollutants in environmental samples: (1) silver nanoparticles; (2) mercury ion

Wu, Zong-Han 09 July 2011 (has links)
I. Combined cloud point extraction and Tween 20-stabilized gold nanoparticles for colorimetric assay of silver nanoparticles in environmental water This study investigated a simple, sensitive and selective method for the colorimetric assay of silver nanoparticles (AgNPs) using Triton X-114-based cloud point extraction (CPE) as a preconcentration step and Tween 20-stabilized gold nanoparticles (Tween-AuNPs) as a colorimetric probe. After heating beyond the cloud point temperature of Triton X-114, a solution containing Triton X-114 micelles and AgNPs separated into a surfactant-rich phase (small volume) and a dilute aqueous phase. AgNPs partitioned into a Triton X-114-rich phase through a hydrophobic interaction between Triton X-114 micelles and AgNPs. After phase separation, the concentrated AgNPs oxidized to form Ag+ upon adding H2O2. The generated Ag+ triggered the aggregation of Tween 20-AuNPs in a high-ionic-strength solution because the reduction of Ag+ on the AuNP surface enabled Tween 20 (stabilizer) to be removed from the NP surface. The efficiency of Triton X-114-based CPE of the AgNPs was found to be iv insensitive to their size and coating type. Under optimal extraction and detection conditions, the selectivity of this method for AgNPs was considerably higher than for other nanomaterials. The minimum detectable concentrations for 7, 22, and 54 nm AgNPs were measured to be 0.1, 420, and 600 ng/mL, respectively. This method was successfully applied to the analysis of 7 nm AgNPs in drinking water, tap water and seawater. Keyword: silver nanoparticles, gold nanoparticles, cloud point extraction, Tween-20, colorimetric assay II. Functionalized silver nanoparticles as an extracting and preconcentrating agent for detection of mercury ions In this research we provided highly sensitive and selective for fluorescence assay of combined polythymine oligonucleotide (PolyT) with silver nanoparticles (AgNPs) as an extracting agent to detect mercury ion in environmental water. According to previous researches, PolyT will form a hairpin structure in the presence of Hg2+, this structure provide several 3-D grooves that the fluorescent dye can inlay with it. SYBR Green I (SG) is a staining dye for DNA, when binding with single strand DNA, it shows low fluorescence. On the contrast, SG inlay with grooves of hairpin structure, it shows v 11-fold of fluorescence signal. Hence, we used SG as a fluorescence probe for Hg2+. We modified thiol group at the 5¡¦ of PolyT DNA, because of forming silver sulfur bond, PolyT will able to modified on the surface of AgNPs. PolyT33SH-AgNPs are the extracting and concentrating agent in Hg2+ solution, by the centrifugation, we collected the PolyT33SH-AgNPs. For the purpose of releasing PolyT from AgNPs¡¦ surface, we adding H2O2 to oxidize the AgNPs into Ag+. By mixing buffer and SG into previous solution, mercury ion could be detected. In this study, we successfully detecting Hg2+ in the aqueous solution contained drinking water and tap water. The detection limit in drinking water is 20 pM, which is below Environmental Protection Agency limit for Hg2+ in drinkable water (10 nM), the linear range is from 50-600 pM. On the other hand, the detection limit in tap water is 50 pM, linear range is from 100-700 pM. Keyword: silver nanoparticles, mercury ion, PolyT, SYBR Green I, thymine
8

CORRELATION BETWEEN ENDOMETRIAL MARKERS AND PREGNANCYOUTCOME IN WOMEN WITH UNEXPLAINED INFERTILITY

Runesson, Liselotte January 2010 (has links)
ABSTRACT A defect implantation process is the major reason for unexplained infertility. Estrogen andprogesterone are steroid hormones preparing the endometrium for implantation. They mediatetheir effect through their receptors: estrogen receptor alpha and beta and progesteronereceptor A and B, respectively. Leukemia inhibitory factor (LIF), which is also important forimplantation, mediates its effect through LIF receptor and the coreceptor, gp130, and is downregulated by suppressors of cytokine signaling 1. The aim of the study was to compare thelevels of the steroid hormone receptors and LIF related factors in the endometrium of twogroups of women with the diagnosis unexplained infertility: one that became pregnant afterassisted reproduction and one that did not become pregnant. Before treatment of thesewomen, endometrial mRNA was collected during the window of implantation in themenstrual cycle. The levels of specific mRNAs were measured with real-time PCR. Womenwho had become pregnant had a significantly higher level of steroid hormone receptors. Thus,these proteins seem to be important for a pregnancy and may be suitable as receptivitymarkers.
9

Effect of advanced reproductive technologies on smallholders' pig productivity in Gauteng Province

Matabane, Matshidiso Bailekae January 2018 (has links)
Thesis (Ph.D. (Animal Production)) --University of Limpopo, 2018 / Pigs are of high economic importance, especially among the smallholder pig farmers as they contribute to human nutrition, food security, poverty alleviation, enhanced livelihood and creation of employment for the rural community. However, reproductive inefficiency is the main limiting factor due to inaccessibility to superior germplasm. Therefore, advances in reproductive technologies such as oestrus synchronization and artificial insemination (AI) offers unprecedented opportunities for livestock improvement for smallholder pig farmers. The first objective determined the status of pig productivity in smallholder farms of Gauteng Province prior to the introduction of advanced reproductive technologies (ARTs). The population was divided into four strata, namely West Rand, Ekurhuleni, Tshwane and Sedibeng district municipalities. A proportional stratified random sampling procedure was used to select 71 smallholder pig farmers with the assistance of extension officers from Gauteng Department of Agriculture and Rural Development (GDARD). The majority of the respondents were males (67%) and were above 50 years of age (67%), whilst 56% of the respondents had high school education. Majority of the respondents privately owned the farms (62%) and the farm infrastructure had facilities with low cost housing and modern facilities. Additionally, 47% of the respondents fed their pigs with feed swill. A large proportion of the respondents did not vaccinate their pigs (81%). Majority of respondents did not identify their pig herds (63%). Interestingly, majority of the respondents did not have breeding boars (73%) and sold their pigs at auctions (70%). The second objective determined semen characteristics evaluated by a Computer Aided Sperm Analyser® (CASA®) as a measure of boar fertility to be used for artificial insemination (AI). Sixteen ejaculates were collected from three Large White boars that are routinely used for semen collection purposes using the gloved-hand technique. The semen was extended with a commercial semen extender; Beltsville Thawing Solution, and the AI dose used consisted of 80mL semen sample (3×109 spermatozoa/mL). Aliquots of diluted semen were evaluated for spermatozoa motility using CASA®. Spermatozoa viability was evaluated using Synthetic Binding CD-14 (SYBR+)/Propidium Iodide (PI-), whereas spermatozoa morphology was evaluated using Eosin Nigrosin stain. The average semen volume, concentration and pH were 210 mL, 264.8 x 106 spermatozoa/mL and 7.1, respectively. The average values for total spermatozoa motility was 95.1%, ranging from 82.7 and 98.5%. However, XIX there were lower values found for progressive spermatozoa motility, ranging from 13.6 to 39.0%. The mean values for morphologically normal spermatozoa ranged from 47.8-60.9% and live spermatozoa ranged from 71.8-77.7%. The third objective determined sow fertility following AI at smallholder farms A total of 73 multiparous sows were artificially inseminated. Conception rates, farrowing rates, litter size and number born alive were recorded. The average conception and farrowing rates were 78.1 and 57.5%, respectively. Furthermore, AI resulted in acceptable fecundity (i.e., 11.8 litter size and 10.0 number of piglets born alive). The fourth objective determined the relationship between spermatozoa quality characteristics and sow fertility at smallholder farms in Gauteng Province. Of all fertility characteristics studied, conception rate was significantly related to total spermatozoa motility rate (r= 0.37, P<0.01), progressive motility (r= 0.31, P<0.01) and rapid motility (r= 0.40, P<0.01), although relatively low. There was a low negative relationship between spermatozoa morphological characteristics and fertility (P>0.05). The fifth objective determined the pre-weaning growth performance of piglets born following AI at smallholder farms of Gauteng province. Individual piglets were weighed using an electronic weighing scale. Litter size, number of piglets born alive, number of piglets weaned, the average piglet birth weight and average piglet weaned weight were recorded. The average litter size was 11.8 ± 0.2. The average birth weight and weaning weights were 1.9 and 6.2 kg, respectively. No significant differences were found between male and female piglets for all the growth performance characteristics. Piglets born during winter had a significantly higher (P<0.05) birth and weaning weight as compared to autumn and summer months. Season had a significant effect on birth and weaning weight (P<0.01). However, sex of piglets had no effect on all the characteristics recorded (P>0.05). The interaction between sex and season was only observed on the total number of weaned piglets (P<0.01). A highly significant positive correlation was found between litter size and number of piglets born alive (r= 0.86) and total number of piglets weaned (r= 0.50). A highly significant correlation was found between total number of piglets born alive and total number of piglets weaned (r= 0.55). In conclusion, the study demonstrated the potential benefit of adopting AI technology under smallholder production systems to disseminate superior genetic material to smallholder pig farmers in Gauteng Province. The total spermatozoa motility, progressive and rapid spermatozoa motility were the only spermatozoa motility characteristics significantly correlated XX with conception rate. Conversely, litter size and number born alive were not correlated with CASA® spermatozoa motility attributes. No relationships existed between spermatozoa morphological characteristics and fertility. The sex ratio percentage of piglets born following AI was 52:48% (females: males). The number of piglets born alive was 10.2 and 9.5 for number piglets weaned. Season influenced birth to weaning weight. However, sex had no significant influence at birth and weaning weight. Litter size affects the number of piglets born alive and weaned. The study showed that the introduction of advanced reproductive technologies improved productivity of pigs at smallholder pig farms in Gauteng Province. / Gauteng Department of Agriculture and Rural Development (GDARD) and Southern African Science Service Centre for Climate Change and Adaptive Land Management (SASSCAL
10

Efecto de diversas técnicas para visualizar la placa metafásica y el corpúsculo polar sobre la capacidad de desarrollo de ovocitos porcinos madurados in vitro

Maside Mielgo, Carolina 14 December 2012 (has links)
La transferencia nuclear de células somáticas (SCNT) en la especie porcina se ha convertido en una herramienta muy útil para para la elaboración de modelos genéticos de enfermedades humanas y para el uso en xenotransplantes. Aunque el número de cerdos clonados aumenta cada año, la eficiencia total de esta tecnología es todavía muy baja. Uno de los pasos más difíciles de la SCNT en porcino es la enucleación del ovocito, principalmente debido a que su citoplasma contiene numerosas gotas lipídicas. El principal objetivo de la tesis fue evaluar el efecto de diversas técnicas para visualizar la placa metafásica y el corpúsculo polar sobre la capacidad de desarrollo de ovocitos porcinos madurados in vitro. / Somatic cell nuclear transfer (SCNT) technology in porcine has become a very useful tool for the elaboration of genetic models for human diseases and the use in xenotransplantation. The efficiency of SCNT is still very low, although the number of cloned pigs increases each year. One of the hardest steps of porcine SCNT is the enucleation of the oocyte because its cytoplasm contains many lipid droplets. The main objective of this thesis was to assess the effect of several approaches to visualize the metaphase II plate and the first polar body on the developmental ability of in vitro mature porcine oocytes.

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