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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.
11

The susceptibility patterns of eight antimicrobial agents for potential treatment of Rhodococcus equi pneumonia in foals

Daniels, Steven Antonn 17 February 2005 (has links)
Rhodococcus equi is a common cause of severe pneumonia in foals, and is an opportunistic pathogen in immunocompromised humans. In combination, erythromycin and rifampin are the most commonly used antimicrobials in treating R. equi in foals. To provide reliable treatment, it is imperative to determine the mean inhibitory concentrations (MICs) of other antimicrobial agents in the event that certain strains of R. equi develop resistance to the current treatment. Several strains of R. equi have developed resistance to various antibiotics. In this study, R. equi strain 288 was completely resistant to rifampin with a MIC > 256ug/ml. The MICs of ethambutol, clarithromycin, azithromycin, isoniazide, ethionamide, rifampin, erythromycin, and linezolid of ninety-five R. equi isolates were also determined in this study. These isolates were obtained from the lungs and transtracheal washes of foals. In addition to these strains, three National Committee for Laboratory Clinical Standards (NCCLS) quality control strains were also tested: R. equi ATCC 6939, R. equi ATCC 33701, and S. pneumoniae 49619. Each drug was tested in triplicate and the MIC 50’s and MIC 90’s were determined for each drug. Ethambutol, isoniazide, and ethionamide were completely ineffective against R. equi. with MICs > 250ug/ml. Rhodococcus equi strains were more susceptible to clarithromycin (MIC 90 = 0.23 ug/ml) than to azithromycin (MIC 90 = 2.33 ug/ml), rifampicin (MIC 90 = 0.67ug/ml), erythromycin (MIC 90 = 1.2ug/ml), and linezolid (MIC 90 = 4ug/ml).
12

The susceptibility patterns of eight antimicrobial agents for potential treatment of Rhodococcus equi pneumonia in foals

Daniels, Steven Antonn 17 February 2005 (has links)
Rhodococcus equi is a common cause of severe pneumonia in foals, and is an opportunistic pathogen in immunocompromised humans. In combination, erythromycin and rifampin are the most commonly used antimicrobials in treating R. equi in foals. To provide reliable treatment, it is imperative to determine the mean inhibitory concentrations (MICs) of other antimicrobial agents in the event that certain strains of R. equi develop resistance to the current treatment. Several strains of R. equi have developed resistance to various antibiotics. In this study, R. equi strain 288 was completely resistant to rifampin with a MIC > 256ug/ml. The MICs of ethambutol, clarithromycin, azithromycin, isoniazide, ethionamide, rifampin, erythromycin, and linezolid of ninety-five R. equi isolates were also determined in this study. These isolates were obtained from the lungs and transtracheal washes of foals. In addition to these strains, three National Committee for Laboratory Clinical Standards (NCCLS) quality control strains were also tested: R. equi ATCC 6939, R. equi ATCC 33701, and S. pneumoniae 49619. Each drug was tested in triplicate and the MIC 50’s and MIC 90’s were determined for each drug. Ethambutol, isoniazide, and ethionamide were completely ineffective against R. equi. with MICs > 250ug/ml. Rhodococcus equi strains were more susceptible to clarithromycin (MIC 90 = 0.23 ug/ml) than to azithromycin (MIC 90 = 2.33 ug/ml), rifampicin (MIC 90 = 0.67ug/ml), erythromycin (MIC 90 = 1.2ug/ml), and linezolid (MIC 90 = 4ug/ml).
13

Trade-offs of Antenna Fabrication Techniques

Ryken, Marv 10 1900 (has links)
ITC/USA 2014 Conference Proceedings / The Fiftieth Annual International Telemetering Conference and Technical Exhibition / October 20-23, 2014 / Town and Country Resort & Convention Center, San Diego, CA / This paper addresses the future military munitions' system requirements for antennas in terms of the existing versus new fabrication technology. The antenna requirements of the future smart munitions will be GPS for precision guidance and TM for system performance testing. The environmental requirements remain the same; large temperature operating range with operation at high temperatures and high shock capable. As usual, the munitions are getting smaller, frequency bandwidth is getting larger, and the cost of the antennas must be minimized in production quantities. In particular this paper compares the existing antenna fabrication technology of Teflon based dielectric printed circuits versus multilayer alumina in the green state, a technology that has been perfected for fabricating microwave integrated circuits (MIC's). The trade-offs that will be addressed are temperature, shock, cost, tunability, loss, size, dielectric constant, and frequency bandwidth. There has been a significant effort to miniaturize the GPS and TM antenna using higher dielectric constant materials. The most popular direction of this effort has been to use ceramic impregnated Teflon. The ultimate temperature performance is the material with a dielectric constant around 2 since this material exhibits a very low coefficient of change with temperature. Materials are available with nominal dielectric constants of 6 and 10 to reduce the size of the antenna but the coefficient of change with temperature is very large and leaves these materials marginal for military temperature ranges. There have also been two other problems with Teflon based printed circuit boards, forming and bonding the boards in a 3D shape and homogeneity of the dielectric constant in the board and after bonding. These problems usually make tuning a requirement and drive the cost of antenna fabrication up. There has been a revolution in MIC's. The circuits are now being made with multiple layers of ceramic (alumina) with interlayer conductive connections and a nominal dielectric constant of 10. The layers are formed in the green state and fired at high temperature and the resulting alumina substrate has a very low coefficient of change with temperature and low loss. Since this procedure is now beyond development, the cost is low and the volume capability is high. Another significant point is that the part can be any shape since the substrate is done in the green state (formable) and then fired.
14

Deriváty pyrazinamidu jako potenciální antimikrobní látky / Pyrazinamide derivatives as potential antimicrobial compounds

Čečetková, Martina January 2018 (has links)
Charles University, Pharmaceutical Faculty in Hradec Králové Department: Department of Pharmaceutical Chemistry and Pharmaceutical analysis Candidate: Martina Čečetková Supervisor: PharmDr. Jan Zitko, Ph.D. Title of Diploma Thesis: Pyrazinamide derivatives as potential antimicrobial compounds Even in 21st century, tuberculosis still remains a serious and global health threat. Tuberculosis is one of the 10 most common causes of death, the most burdened are developing countries, but this disease infects up to 1/3 of population worldwide. Due to ineffective treatment of tuberculosis in developing countries, the prevalence of tuberculosis which does not respond to standard treatment is increasing. It is necessary to develop new drugs effective against multidrug-resistant tuberculosis and prevent further spread of the disease. The design of final structures is based on previously synthesized molecule 6- chloro-N-(4-(4-fluorophenyl)thiazol-2-yl)pyrazine-2-carboxamide, which structure comes from first line antitubercular pyrazinamide (PZA) and 4-arylthiazol-2-amine scaffold with formerly identified antimycobacterial activity. This starting compound exhibits high activity against M. tuberculosis described by MIC = 0,78 µg/mL and low cytotoxicity. The object of study was to determine effect of substitution...
15

The Collaborative Performance of Open Mic Poetry and the Art of Making Do

Hassert, Joseph 01 May 2014 (has links)
Open mic poetry events are representative examples of a widespread and socially significant performance phenomenon--the relational and dialogic art and activism of the sustained encounter as a demonstration of the possibility for new social relations. Open mic performances center the pleasure of creating and sharing art and relationships in a manner that works against the value systems of capitalistic exchange and enterprise. I conduct an autoethnographic study of the Transpoetic Playground--a reoccurring open mic poetry event in Carbondale, Illinois. This study mixes performative writing, poetry, and personal narrative with the ethnographic methods of participation observation and interviewing in order to tell a story of an amateur performance poetry community and what it can teach about how to resist the constraints of contemporary socio-communicative relations.
16

Investigation of Star Formation: Instrumentation and Methodology

January 2012 (has links)
abstract: A thorough exploration of star formation necessitates observation across the electromagnetic spectrum. In particular, observations in the submillimeter and ultra-violet allow one to observe very early stage star formation and to trace the evolution from molecular cloud collapse to stellar ignition. Submillimeter observations are essential for piercing the heart of heavily obscured stellar nurseries to observe star formation in its infancy. Ultra-violet observations allow one to observe stars just after they emerge from their surrounding environment, allowing higher energy radiation to escape. To make detailed observations of early stage star formation in both spectral regimes requires state-of-the-art detector technology and instrumentation. In this dissertation, I discuss the calibration and feasibility of detectors developed by Lawrence Berkeley National Laboratory and specially processed at the Jet Propulsion Laboratory to increase their quantum efficiency at far-ultraviolet wavelengths. A cursory treatment of the delta-doping process is presented, followed by a thorough discussion of calibration procedures developed at JPL and in the Laboratory for Astronomical and Space Instrumentation at ASU. Subsequent discussion turns to a novel design for a Modular Imager Cell forming one possible basis for construction of future large focal plane arrays. I then discuss the design, fabrication, and calibration of a sounding rocket imaging system developed using the MIC and these specially processed detectors. Finally, I discuss one scientific application of sub-mm observations. I used data from the Heinrich Hertz Sub-millimeter Telescope and the Sub-Millimeter Array (SMA) to observe sub-millimeter transitions and continuum emission towards AFGL 2591. I tested the use of vibrationally excited HCN emission to probe the protostellar accretion disk structure. I measured vibrationally excited HCN line ratios in order to elucidate the appropriate excitation mechanism. I find collisional excitation to be dominant, showing the emission originates in extremely dense (n&sim10;11 cm-3), warm (T&sim1000; K) gas. Furthermore, from the line profile of the v=(0, 22d, 0) transition, I find evidence for a possible accretion disk. / Dissertation/Thesis / Ph.D. Physics 2012
17

Avaliação de biofilmes formados por isolados de Listeria monocytogenes provenientes de laticínios e perfil de resistência a agentes sanitizantes / Evaluation of biofilms formed by Listeria monocytogenes isolated from dairy plants and resistance to sanitizing agents

Drucila Cristina Factor Carandina 15 March 2013 (has links)
O objetivo do presente estudo foi avaliar a capacidade de isolados de Listeria monocytogenes em formar biofilmes em superfícies inertes, bem como sua resistência a agentes sanitizantes. Foram utilizados 37 isolados provenientes de ambiente de laticínios, amostras de queijos e salmoura, pertencentes à coleção do Laboratório de Microbiologia e Micotoxicologia de Alimentos (LMMA) do Departamento de Engenharia de Alimentos da FZEA/USP. Dos 37 isolados avaliados, 67,6% eram pertencentes ao sorotipo 4b. Três isolados de L. monocytogenes foram obtidos de salmoura, 5 foram obtidos de caixas plásticas, 1 de queijo Prato, 1 da mão de manipulador de embalagens, e 27 foram isolados de superfícies sem contato com alimentos (piso da sala de pasteurização, piso da câmara fria, ralo da câmara fria ou estrado da câmara fria). Os isolados de L. monocytogenes apresentaram maior capacidade de produzir biofilme nos ensaios com cupons de aço inox (43,2% dos isolados), seguido dos ensaios em microplaca de poliestireno (16,2%), cupons de borracha (13,5%) e discos de silicone (2,7%). As células de L. monocytogenes aderidas nas superfícies do aço inox foram visualizadas sob microscopia eletrônica de varredura após 48 horas de incubação a 37ºC. Dezenove isolados de L.monocytogenes, os quais produziram biofilmes nos ensaios com aço inox, borracha ou silicone, foram testados para determinação da eficiência de sanitizantes pelo método de concentração inibitória mínima (CIM), utilizando-se ácido peracético (2%), cloreto de banzalcônio (1%), digluconato de clorexidina (2%), hipoclorito de sódio (2%) e tintura de iodo (2%). Os isolados de L. monocytogenes analisados apresentaram resistência a ácido peracético, hipoclorito de sódio e tintura de iodo, cujos valores de CIM foram 3,12%, 6,25% e 6,25%, respectivamente. Nenhum isolado apresentou resistência a cloreto de benzalcônio e digluconato de clorexidina, os quais foram eficientes para inibição de isolados de L. monocytogenes provenientes de amostras de queijos e ambientes de laticínios. A L. monocytogenes apresenta capacidade de persistir em ambiente de laticínios sob a forma de biofilme em várias superfícies inertes como aço inox, borracha e silicone, o que pode representar uma fonte permanente de contaminação para produtos e processos de obtenção de leite e derivados. / The objective of the present study was to evaluate the ability of isolates of Listeria monocytogenes to form biofilms and their resistance to sanitizers. Thirty seven strains belonging to the collection of the Laboratory of Microbiology and Food Mycotoxicology (LMMA), Department of Food Engineering of FZEA / USP, were used. Of the 37 isolates, 67.6% belonged to serotype 4b. Three isolates of L. monocytogenes were obtained from brine, 5 were obtained from plastic boxes, one of Prato cheese, one from the packaging handler\'s hand, and 27 were isolated from non-food contact surfaces (pasteurization room floor, the floor of the cold room, the drain cold or pallet from the cold chamber). The isolates of L. monocytogenes showed greater ability to produce biofilm in the assays with stainless steel coupons (43.2% of isolates), followed by polystyrene micro plate (16.2%), rubber coupons (13.5%) and silicone disks (2.7%) assays. Cells of L. monocytogenes attached to stainless steel surfaces were viewed under scanning electron microscopy after 48 hours incubation at 37°C. Nineteen strains of L. monocytogenes, which were considered biofilms producers in the assays with stainless steel, rubber or silicone, have been tested to evaluate the efficiency of the sanitizing method by means of the minimum inhibitory concentration (MIC), using peracetic acid (2%), sodium chloride benzalkonium (1%), chlorhexidine digluconate (2%), sodium hypochlorite (2%) and iodine solution (2%). The isolates of L. monocytogenes analyzed showed resistance to peracetic acid, sodium hypochlorite and iodine tincture, with MIC values of 3.12%, 6.25% and 6.25%, respectively. No isolate showed resistance to benzalkonium chloride and chlorhexidine digluconate, which were effective for inhibiting the isolates of L. monocytogenes from samples of cheeses and dairy environments. In conclusion, L. monocytogenes has the ability to persist in the environment of dairy products by forming biofilms in several inert surfaces such as stainless steel, rubber and silicone, which may represent a continuing source of contamination to manufacture processes of dairy products.
18

Analýza šifrovacích algoritmů ve standardu 802.11 / Analysis of Cryptographic Algorithms 802.11

Vojtíšek, Jindřich January 2014 (has links)
This work deals with wireless standard 802.11, primaly about security algorithms used in them. Further there is made analysis of algorithms WEP, WPA and WPA2. This algorithms are described how coding by them works and for easier understandig are added block schemes of their principles. In practical part is realized algorithms WEP, WPA and WPA2 in program Matlab simulink. Model is complemented by graphs which shows how data changes when comming throught this systems.
19

Návrh, syntéza a hodnocení derivátů pyrazinamidu jako potenciálních antimikrobních sloučenin II / Design, synthesis and evaluation of pyrazinamide derivatives as potential antimicrobial compounds II

Kučerová, Lucie January 2020 (has links)
Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Chemistry and Pharmaceutical Analysis Candidate: Lucie Kučerová Supervisor: doc. PharmDr. Jan Zitko, Ph.D. Consultant: PharmDr. Martin Juhás Title of diploma thesis: Design, synthesis and evaluation of pyrazinamide derivatives as potential antimicrobial compounds II Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis complex and is currently one of the most common causes of death from an infectious disease. Treatment of tuberculosis is long-term, combined and controlled to prevent resistance. Resistance is very serious and therefore treatment is always performed with more antituberculars at the same time. Finding new drugs and improving existing ones is a constant part of research. In the theoretical part I tried to summarize information about tuberculosis, its causative agent, diagnostics, possible prevention and treatment strategy. I have described the most commonly used antituberculars, especially the first- line antituberculars - pyrazinamide, from which the derivatives synthesized in my work are based. In the experimental part I described the procedures and reactions used for synthesis of the new compounds, which were formed by combining pyrazinamide with various amino acids. In this...
20

Chaga och Reishis inverkan på bakterietillväxt

Jouni, Fredrik January 2016 (has links)
Chaga och Reishi svamparna har använts i ett flertal länder som t.ex. Kina och Ryssland som folkmedicin. I tidigare studier har Chaga och Reishi svamparna uppvisat ett flertal hälsoeffekter som antiinflammatoriska egenskaper, antivirala effekter, antitumorala effekter samt förhindrandet av mikrobiell tillväxt. Syftet med projektet var att studera Chaga och Reishi svampars antibakteriella effekt. Detta kan leda till nya alternativa bakteriehämmande medel för användning och bekämpning av den ökade spridningen av resistenta bakterier. För att utvinna de hälsobringande ämnena från Chaga och Reishi svamparna utfördes vatten- och etanolextraktioner. Tillväxtkurvor för grampositiva bakterien S. aureus och gramnegativa bakterien E. coli studerades för att se ifall Chaga och Reishi extrakten hämmade bakterietillväxten. Resultatet visade att tillväxtkurvorna med etanolextrakten visade en hämning på både den grampositiva bakterien och den gramnegativa bakterien medan tillväxtkurvorna med vattenextrakten visade svag hämning av bakterietillväxten förutom i tillväxtkurvan för S. aureus med Chaga vattenextrakt. MIC test utfördes för att se vid vilken koncentration som svampextrakten hämmade bakterietillväxten och endast vid koncentrationerna 125 mg/ml och 100 mg/ml hämmades bakterietillväxten med Chaga- och Reishi etanolextrakt. När det gällde Chaga- och Reishi vattenextrakt sågs ingen hämning av bakterietillväxten vid samtliga koncentrationer. / The fungi: Chaga and Reishi have been used in several countries for example China and Russia as folk medicine. In previous studies, Chaga and Reishi have shown numerous health effects such as anti-inflammatory, antiviral, anti tumoral as well as preventing microbial growth. The aim of the project was to study the antibacterial effect of Chaga and Reishi. It may result in knowledge about more alternative bacteriostatic agents produced to combat the expansion of resistant bacteria. The extraction of the medicinal ingredients from Chaga and Reishi was carried out with aqueous- and ethanol extraction. Growth curves for the gram-positive bacterium S. aureus and the gram-negative bacterium E. coli was studied to see if Chaga and Reishi extracts inhibited the growth of the bacteria. The growth curves of ethanol extracts showed inhibition of these gram-positive bacteria and gram-negative bacteria, while the growth curves of aqueous extracts showed no further inhibition of bacterial growth, except in the growth curve of S. aureus with Chaga aqueous extract. MIC test was set up to see at what concentration Chaga and Reishi extracts inhibited the growth of the bacteria and at the concentrations of 125 mg/ml and 100 mg/ml the bacterial growth with Chaga- and Reishi ethanol extract was inhibited. Whereas for Chaga- and Reishi aqueous extract there was no sign of bacterial growth inhibition.

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