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Development of a vaccine against leishmaniasis
Full text linkLeishmania parasites, protozoan parasites transmitted by female sand flies, cause the disease leishmaniasis. Leishmaniasis is responsible for 25,000–65,000 deaths and 0.7–1.0 million new cases per year. At present, there is no clinical vaccine available. Previous studies have indicated that recombinant gamma glutamylcysteine synthetase (γGCS) can protect against L. donovani and L. major infection in a murine model. However, these studies showed that production of full-length recombinant γGCS was problematic and only truncated forms of the protein could be isolated. Therefore, in this study new plasmid constructs were produced for expression of recombinant γGCS from L. donovani, L. major and L. mexicana. Molecular techniques were used to produce a series of plasmids that code for the full-length sequence of γGCS. Constructs were engineered to encode for an N-terminal T7-tag and a C-terminal His-tag, to facilitate isolation of pure and full-length γGCS protein from an Escherichia coli expression vector (pET21a(+)). Optimal expression occurred in transfected E. coli when bacteria were cultured at 18ºC after induction using 0.1 mM isopropyl β-D-1- thiogalactopyranoside. The recombinant protein was found to be present in the soluble fraction and a HisPur™ Ni-NTA spin column purification kit was used to obtain recombinant γGCS. Gel electrophoresis and western blot analysis showed that full length γGCS protein was isolated for all three recombinant proteins. However, subsequent isolation using a T7•Tag® affinity purification kit resulted in insufficient amounts of protein. Vaccine studies were completed using L. tarentolae promastigotes expressing γGCS. Mice were immunised on day 0 and 21 with parasites expressing γGCS from L. donovani alone or a mixture of parasites expressing γGCS from L. donovani, L. major or L. mexicana (triple vaccine). On day 42 mice were infected with L. donovani amastigotes and parasite burdens were determined 14 days later. Protection was associated with a mixed Th1/Th2 response based on specific IgG1 and IgG2a antibodies and on cytokines produced by antigen stimulated splenocytes used in in vitro proliferation assays.Leishmania parasites, protozoan parasites transmitted by female sand flies, cause the disease leishmaniasis. Leishmaniasis is responsible for 25,000–65,000 deaths and 0.7–1.0 million new cases per year. At present, there is no clinical vaccine available. Previous studies have indicated that recombinant gamma glutamylcysteine synthetase (γGCS) can protect against L. donovani and L. major infection in a murine model. However, these studies showed that production of full-length recombinant γGCS was problematic and only truncated forms of the protein could be isolated. Therefore, in this study new plasmid constructs were produced for expression of recombinant γGCS from L. donovani, L. major and L. mexicana. Molecular techniques were used to produce a series of plasmids that code for the full-length sequence of γGCS. Constructs were engineered to encode for an N-terminal T7-tag and a C-terminal His-tag, to facilitate isolation of pure and full-length γGCS protein from an Escherichia coli expression vector (pET21a(+)). Optimal expression occurred in transfected E. coli when bacteria were cultured at 18ºC after induction using 0.1 mM isopropyl β-D-1- thiogalactopyranoside. The recombinant protein was found to be present in the soluble fraction and a HisPur™ Ni-NTA spin column purification kit was used to obtain recombinant γGCS. Gel electrophoresis and western blot analysis showed that full length γGCS protein was isolated for all three recombinant proteins. However, subsequent isolation using a T7•Tag® affinity purification kit resulted in insufficient amounts of protein. Vaccine studies were completed using L. tarentolae promastigotes expressing γGCS. Mice were immunised on day 0 and 21 with parasites expressing γGCS from L. donovani alone or a mixture of parasites expressing γGCS from L. donovani, L. major or L. mexicana (triple vaccine). On day 42 mice were infected with L. donovani amastigotes and parasite burdens were determined 14 days later. Protection was associated with a mixed Th1/Th2 response based on specific IgG1 and IgG2a antibodies and on cytokines produced by antigen stimulated splenocytes used in in vitro proliferation assays
HTS armature study for electrified aviation propulsion motors
Full text linkThe continued expansion of global air traffic has highlighted the urgent need to reduce the global warming impact of the aviation industry. Traditional aircraft systems rely heavily on fossil fuels and contribute significantly to CO₂ and NOₓ emissions. To accomplish the goal of zero-emissions aviation, the proposal of More Electric Aircraft (MEA) or All Electric Aircraft (AEA) propulsion systems stands as a potential solution. Since conventional electric motors are too heavy for aviation, efficient multi-megawatt motors with high power density are needed, and cryogenic superconducting motors are a promising solution thanks to their high current capacity. However, high-temperature superconducting (HTS) coils cannot be widely used as motor armature windings until the cryogenic AC loss is reduced to an acceptable limit regarding motor power density and efficiency requirements.
This thesis presents original research of the design and optimization of HTS armature coils focusing on the AC loss evaluation and reduction. With the help of experimental measurements and numerical simulations analysis, the standard 2G (second generation) HTS insulated coils are found to be competitive to copper/aluminium Litz wires for a megawatt (MW) level cryogenic motor working at a temperature around 40 K. In addition, the AC loss can be reduced by narrowing the tape width or adding a thin layer of stator back iron. This thesis also introduces a novel multi-stack coil structure to improve the HTS stator electrical loading while maintaining the mechanical and thermal stability. The transport current loss of this novel coil is investigated, and the AC loss can be minimized by balancing the inductance between the parallel stacks.The continued expansion of global air traffic has highlighted the urgent need to reduce the global warming impact of the aviation industry. Traditional aircraft systems rely heavily on fossil fuels and contribute significantly to CO₂ and NOₓ emissions. To accomplish the goal of zero-emissions aviation, the proposal of More Electric Aircraft (MEA) or All Electric Aircraft (AEA) propulsion systems stands as a potential solution. Since conventional electric motors are too heavy for aviation, efficient multi-megawatt motors with high power density are needed, and cryogenic superconducting motors are a promising solution thanks to their high current capacity. However, high-temperature superconducting (HTS) coils cannot be widely used as motor armature windings until the cryogenic AC loss is reduced to an acceptable limit regarding motor power density and efficiency requirements.
This thesis presents original research of the design and optimization of HTS armature coils focusing on the AC loss evaluation and reduction. With the help of experimental measurements and numerical simulations analysis, the standard 2G (second generation) HTS insulated coils are found to be competitive to copper/aluminium Litz wires for a megawatt (MW) level cryogenic motor working at a temperature around 40 K. In addition, the AC loss can be reduced by narrowing the tape width or adding a thin layer of stator back iron. This thesis also introduces a novel multi-stack coil structure to improve the HTS stator electrical loading while maintaining the mechanical and thermal stability. The transport current loss of this novel coil is investigated, and the AC loss can be minimized by balancing the inductance between the parallel stacks
Analytical method development and validation for forensic investigation of psychoactive compounds and gastrointestinal fluids characterization
Full text linkDrugs of abuse (DoA) involve a wide range of substances, including illicit drugs (Heroin), prescription medications when used non-medically (benzodiazepines), and even legal substances when misused (alcohol). DoA pose significant public health challenges and social problems, therefore, effective strategies are essential to address these concerns. The aim of this thesis was to screen common DoA in Kuwait and draw a picture on the common trends in illicit DoA. First, ten synthetic cannabinoids (SCs) were investigated, and a LC-MS/MS method was developed for their separation and quantitation. The method was used for screening of these SCs in street samples in Kuwait (Chapter 2). Another three SCs were screened in urine samples collected in Kuwait. A solid phase extraction (SPE) procedure was developed for extraction of the three SCs from urine, followed with a sensitive and specific LC-MS/MS method for their quantitation. (Chapter 3). Next, a sensitive and specific LC-MS/MS method was developed for the detection of six DoA common in Kuwaiti market, namely pregabalin, morphine, amphetamine, methamphetamine, codeine, and diazepam. The six drugs were screened in 150 urine samples collected in Kuwait (Chapter 4). Nowadays, gastrointestinal tract (GIT) media are commonly used to determine drug solubility and bioavailability in vitro during drug development phase. GIT media are susceptible to large variability between individuals and to inter-day fluctuations, in addition to meal intake and biliary and pancreatic secretions. These facts show the importance of characterization of GIT fluid components for accurate determination and prediction of drug bioavailability. The aim of work in this chapter was to characterize common GIT fluid components such as sodium oleate (SO), glyceryl monooleate (GMO), and cholesterol (CHL). An accurate and specific GC-MS method was developed for the determination of these compounds. A derivatization procedure was optimized for the three compounds, where silylation reagent mixture was used to produce their silyl derivatives (Chapter 5).Drugs of abuse (DoA) involve a wide range of substances, including illicit drugs (Heroin), prescription medications when used non-medically (benzodiazepines), and even legal substances when misused (alcohol). DoA pose significant public health challenges and social problems, therefore, effective strategies are essential to address these concerns. The aim of this thesis was to screen common DoA in Kuwait and draw a picture on the common trends in illicit DoA. First, ten synthetic cannabinoids (SCs) were investigated, and a LC-MS/MS method was developed for their separation and quantitation. The method was used for screening of these SCs in street samples in Kuwait (Chapter 2). Another three SCs were screened in urine samples collected in Kuwait. A solid phase extraction (SPE) procedure was developed for extraction of the three SCs from urine, followed with a sensitive and specific LC-MS/MS method for their quantitation. (Chapter 3). Next, a sensitive and specific LC-MS/MS method was developed for the detection of six DoA common in Kuwaiti market, namely pregabalin, morphine, amphetamine, methamphetamine, codeine, and diazepam. The six drugs were screened in 150 urine samples collected in Kuwait (Chapter 4). Nowadays, gastrointestinal tract (GIT) media are commonly used to determine drug solubility and bioavailability in vitro during drug development phase. GIT media are susceptible to large variability between individuals and to inter-day fluctuations, in addition to meal intake and biliary and pancreatic secretions. These facts show the importance of characterization of GIT fluid components for accurate determination and prediction of drug bioavailability. The aim of work in this chapter was to characterize common GIT fluid components such as sodium oleate (SO), glyceryl monooleate (GMO), and cholesterol (CHL). An accurate and specific GC-MS method was developed for the determination of these compounds. A derivatization procedure was optimized for the three compounds, where silylation reagent mixture was used to produce their silyl derivatives (Chapter 5)
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