Novel techniques for microencapsulation of probiotic bacteria

Microencapsulation of living cells such as probiotic bacteria can be used for the protection of the cells from harsh conditions such as low pH and mechanical stress in the digestive system. In this thesis we demonstrate various novel strategies to microencapsulate living yeast cells as a model for probiotic bacteria. We prepared and used sporopollenin microcapsules to encapsulate yeast cells by compressing the sporopollenin particles into a pellet which was exposed to an aqueous suspension of yeast cells in the presence of a biocompatible surface active agent. We also demonstrate that the viability of the cells is preserved after the microencapsulation. We fabricated novel shellac-yeast cells composite microcapsules programmed to release the cells upon change of pH in a narrow range. This was achieved by either spray drying or sprays co-precipitating dispersion of yeast cells in aqueous solution of ammonium shellac doped with a pH-sensitive polyelectrolyte. We also demonstrate that yeast cells retain their viability even when treated with aqueous solutions of low pH. In addition, the pH-triggered release of yeast cells from these composite microcapsules and their disintegration rates were investigated. We developed a theoretical model for the kinetics of yeast cells release from the microcapsules triggered by (i) pH change and (ii) the growth of the cells in a culture media. In a separate strategy of microencapsulation of living cells, we used templates of Pickering emulsions stabilised with latex nanoparticles to fabricate colloidosomes loaded with viable probiotics. Depending on the method of transfer, we have shown that magnetic colloidosomes containing pH-sensitive polyelectrolyte loaded with living cells can be prepared using Pickering emulsion templates. In addition, we demonstrate two strategies to strengthen the stability of water-in-oil Pickering emulsion droplets by interlocking the adsorbed latex particle monolayer: by (i) using oppositely charged polyelectrolyte adsorption or (ii) using polyelectrolyte pre-coated yeast cells which act as cross-linkers inside the water-in-oil droplets. Furthermore, we report the fabrication of 3 D multicellular cellosomes of living cells by using water-in-oil emulsion templates as intermediate. We have used two strategies to assemble yeast cells pre-coated with polyelectrolytes in water-in-oil emulsion droplets stabilised with either surfactant or solid particles. The emulsion droplets containing oppositely charged yeast cells linked together by electrostatical interactions were shrunken to compact structures upon addition of dry octanol and subsequently transferred into water to fabricate cellosomes. In summary, this thesis contributes an arsenal of new methods for microencapsulation of living cells for the purpose of their protection and triggered release. The results of this thesis can be used in the formulation of better probiotic products, protection and release of cells implants, tissue engineering and development of live vaccines

Comprehensive Analysis and Forensic Investigation of Cyanide, Thiocyanate, and 2-Amino-2-Thiazoline-4-Carboxylic Acid In-Ante- and Postmortem Blood Utilizing Advanced Analytical Techniques

Cyanide (CN), present as cyanide anion (CN-) or hydrogen cyanide (HCN), is a deadly poison. The main mechanism of CN toxicity is blocking terminal electron transfer, leading to cellular hypoxia, cytotoxic anoxia, and potential death. Determining blood CN concen-trations along with its major metabolite, thiocyanate (SCN-), is crucial. A sensitive method for concurrent detection of CN and SCN- from human ante- and post-mortem blood via liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis was devel-oped. The method involved active microdiffusion with chemical modification using naph-thalene-2,3-dicarboxaldehyde (NDA) and taurine, while monobromobimane (MBB) mod-ification was used for SCN-. The method showed good sensitivity for CN with antemortem limits-of-detection (LODs) of 219 nM and 605 nM for CN and SCN-, respectively, and postmortem LODs of 352 nM and 509 nM. The method also produced good accuracy and precision, detecting elevated levels of CN and SCN- in both ante- and post-mortem blood samples from CN-exposed swine compared to non-exposed swine. Forensic verification of CN poisoning by direct CN analysis in postmortem blood is challenging due to the instability of CN in biological samples. CN metabolites, SCN- and 2-aminothiazoline-4-carboxylic acid (ATCA), have been proposed as more stable bi-omarkers, but their appropriateness for verification of poisoning remains unclear. The behavior of CN, SCN-, and ATCA in postmortem swine stored at 4°C and postmortem blood stored at room temperature (25°C; RT) and typical human body temperature (37°C; HBT) was evaluated. After poisoning swine with CN, the blood concentration of each CN biomarker increased well above the baseline. In postmortem swine, elevated CN concen-trations declined rapidly, whereas SCN- and ATCA concentrations remained relatively sta-ble. The decline in CN accelerated as the storage temperature increased, where CN was below baseline levels within 50, 74, and 120 h for postmortem swine at 4°C and post-mortem blood at RT and HBT, respectively. The half-lifes (t1/2) of CN were 34.3 h, 10.8 h, and 6.6 h at 4 °C (in postmortem swine), RT, and HBT, respectively. SCN- and ATCA were more stable than CN at all storage conditions, producing t1/2s of 15-19 days and 23-26 days for SCN- and ATCA, respectively. ATCA exhibited the most extended t1/2 and most significant increase above baseline levels for the CN biomarkers tested, making it the most appropriate biomarker for confirming CN poisoning via postmortem blood analysis

Energy Storage Systems for Traction and Renewable Energy Applications

Energy storage systems are the set of technologies used to store various forms of energy, and by necessity, can be discharged. Energy storage technologies have a wide range of characteristics and specifications. Like any other technology, each type of energy storage has its pros and cons. Depending on the application, it is crucial to perform a tradeoff study between the various energy storage options to choose the optimal solution based on the key performance objectives and various aspects of those technologies. The purpose of this thesis is to present a thorough literature review of the various energy storage options highlighting the key tradeoffs involved. This thesis focuses on evaluating energy storage options for traction and renewable energy applicationsHybrid Electric Vehicles (HEVs) is one key application space driving breakthroughs in energy storage technologies. The focus though has been typically on using one type of energy storage systems. This thesis investigates the impact of combining several types of batteries with ultracapacitor. A case study of integrating two energy storage systems in a series-parallel hybrid electric vehicle is simulated by using MATLAB-SIMULINK software.The other key application space is renewable energy especially wind and solar. Due to the intermittent nature of renewable energy sources, energy storage is a must to achieve the required power quality. Therefore, this thesis aims to investigate different cases of combining different types of energy storage with wind and solar. Hybrid Optimization Model for Electric Renewables (HOMER) software is utilized to study the economic and sizing aspects in each case

Novel techniques for microencapsulation of probiotic bacteria

Microencapsulation of living cells such as probiotic bacteria can be used for the protection of the cells from harsh conditions such as low pH and mechanical stress in the digestive system. In this thesis we demonstrate various novel strategies to microencapsulate living yeast cells as a model for probiotic bacteria. We prepared and used sporopollenin microcapsules to encapsulate yeast cells by compressing the sporopollenin particles into a pellet which was exposed to an aqueous suspension of yeast cells in the presence of a biocompatible surface active agent. We also demonstrate that the viability of the cells is preserved after the microencapsulation.We fabricated novel shellac-yeast cells composite microcapsules programmed to release the cells upon change of pH in a narrow range. This was achieved by either spray drying or sprays co-precipitating dispersion of yeast cells in aqueous solution of ammonium shellac doped with a pH-sensitive polyelectrolyte. We also demonstrate that yeast cells retain their viability even when treated with aqueous solutions of low pH. In addition, the pH-triggered release of yeast cells from these composite microcapsules and their disintegration rates were investigated. We developed a theoretical model for the kinetics of yeast cells release from the microcapsules triggered by (i) pH change and (ii) the growth of the cells in a culture media.In a separate strategy of microencapsulation of living cells, we used templates of Pickering emulsions stabilised with latex nanoparticles to fabricate colloidosomes loaded with viable probiotics. Depending on the method of transfer, we have shown that magnetic colloidosomes containing pH-sensitive polyelectrolyte loaded with living cells can be prepared using Pickering emulsion templates. In addition, we demonstrate two strategies to strengthen the stability of water-in-oil Pickering emulsion droplets by interlocking the adsorbed latex particle monolayer: by (i) using oppositely charged polyelectrolyte adsorption or (ii) using polyelectrolyte pre-coated yeast cells which act as cross-linkers inside the water-in-oil droplets.Furthermore, we report the fabrication of 3 D multicellular cellosomes of living cells by using water-in-oil emulsion templates as intermediate. We have used two strategies to assemble yeast cells pre-coated with polyelectrolytes in water-in-oil emulsion droplets stabilised with either surfactant or solid particles. The emulsion droplets containing oppositely charged yeast cells linked together by electrostatical interactions were shrunken to compact structures upon addition of dry octanol and subsequently transferred into water to fabricate cellosomes.In summary, this thesis contributes an arsenal of new methods for microencapsulation of living cells for the purpose of their protection and triggered release. The results of this thesis can be used in the formulation of better probiotic products, protection and release of cells implants, tissue engineering and development of live vaccines

Employee perceptions in multinational companies : a case study of the Saudi Arabian basic industries corporation.

SIGLEAvailable from British Library Document Supply Centre-DSC:DX193939 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Reliability Analysis of Dual-Purpose (Power and Water) Production Station, Volume I

This thesis presents the outcome of applying reliability engineering analysis techniques to a thermal dual-purpose (power&water) production station. The thermal cycle of the station is a fossil fueled steam boiler, condensing-extraction steam turbine, a generator, and a multi-stage flash evaporator

Reliability Analysis of Dual-Purpose (Power and Water) Production Station, Volume II, Appendix 1

Abstract Not Provided

Представления учителей биологии средней школы о науке, технике, технике и математике (STEM) Тенденция в образовании и уровень самоэффективности обучения

This paper attempts to identify the perceptions of secondary school biology teachers on Science, Technology, Engineering and Math (STEM) educational trend and the related teaching requirements. Being conducted with 37 secondary school biology teachers in AlKharj Governorate in Saudi Arabia, the study also measures their level of teaching self-efficacy in the light of that STEM educational trend. A test and a questionnaire were prepared for this purpose. The data that were collected via the survey and the given test were analyzed. Pearson Correlation Coefficient was used to validate the internal consistency of the questionnaire. The statistical stability of the test and the questionnaire were calculated according to Alpha-Cronbach Coefficient. The results of the study show that there is a weakness in the teachers' knowledge of the STEM trend. Their opinions and answers reveal that their perceptions of this kind of education and the related teaching requirements is weak. The results also show that the level of teaching self-efficacy in the light of the STEM educational trend ranges from medium to high. In addition, while there are no statistically significant differences in three different variables, there are statistically significant differences in other two variables in the study. The study ends with some recommendations that can help in developing the teachers' perceptions on STEM education and their teaching self-efficacy.Este artículo intenta identificar las percepciones de los maestros de biología de la escuela secundaria sobre la tendencia educativa de Ciencia, Tecnología, Ingeniería y Matemáticas (STEM) y los requisitos de enseñanza relacionados. Realizado con 37 profesores de biología de la escuela secundaria en la gobernación de AlKharj en Arabia Saudita, el estudio también mide su nivel de autoeficacia docente a la luz de esa tendencia educativa STEM. Se preparó una prueba y un cuestionario para este propósito. Se analizaron los datos que se recopilaron a través de la encuesta y la prueba dada. El coeficiente de correlación de Pearson se utilizó para validar la consistencia interna del cuestionario. La estabilidad estadística de la prueba y el cuestionario se calcularon de acuerdo con el coeficiente de Alpha-Cronbach. Los resultados del estudio muestran que existe una debilidad en el conocimiento de los docentes sobre la tendencia STEM. Sus opiniones y respuestas revelan que sus percepciones de este tipo de educación y los requisitos de enseñanza relacionados son débiles. Los resultados también muestran que el nivel de autoeficacia docente a la luz de la tendencia educativa STEM varía de medio a alto. Además, aunque no existen diferencias estadísticamente significativas en tres variables diferentes, existen diferencias estadísticamente significativas en otras dos variables en el estudio. El estudio finaliza con algunas recomendaciones que pueden ayudar a desarrollar las percepciones de los maestros sobre la educación STEM y su autoeficacia docente.В этой статье предпринята попытка определить восприятие учителей биологии в средней школе в области науки, технологий, техники и математики (STEM) и связанных с ними требований к преподаванию. В исследовании, проводимом вместе с 37 учителями биологии в средней школе в провинции Аль-Хардж в Саудовской Аравии, также измеряется уровень их самообучаемости в свете этой образовательной тенденции STEM. Для этого были подготовлены тест и анкета. Данные, которые были собраны с помощью опроса и данного теста были проанализированы. Коэффициент корреляции Пирсона был использован для проверки внутренней согласованности вопросника. Статистическая устойчивость теста и вопросник были вычислены в соответствии с альфа-Кронбах коэффициента. Результаты исследования показывают, что существует недостаток в знаниях учителей тенденции STEM. Их мнения и ответы показывают, что их восприятие такого рода образование и связанные с ними требования обучения является слабым. Результаты также показывают, что уровень обучения самоэффективность в свете STEM образовательного тренда в диапазоне от среднего до высокого. Кроме того, в то время как нет никаких статистически значимых различий в трех различных переменных, существуют статистически значимые различия в двух других переменных в исследовании. Исследование заканчивается с некоторыми рекомендациями, которые могут помочь в разработке представлений учителей на STEM образования и их преподавание самоэффективности

The Role of Social Responsibility Accounting on Achieving Competitive Advantages (An Empirical Study from Perspectives of a Number of Employees in Accounting and Financial Departments in a Number of Private Universities in Iraqi Kurdistan Region)

The discussion about mystical intuition, imagination and reason has been a main problem for philosophers and mystics and some discussions has been made about the limits of understanding and perception of each concept. Ibn Arabi is one of the biggest Islamic mystics and has remarkable views in this field and his works in the field of mystic are of great importance. Sad Aldin Shirazi, Iranian philosopher from the Safavi era, known as Mola Sadra, which is one of the illuminated philosophers, has done lots of research about Ibn Arabi’s works. In this study, we compare the point of views of these two philosophers and their perception about the understanding the nature of God, while analyzing the opinions of them about reason, imagination and mystical intuition. We have concluded that Mola Sadra, as same as Ibn Arabi, considers reason the first being and the Mohhamadi truth and categorizes it and says that the reason of creatures is limited for understanding God. In his opinion, reason gets help from feeling and imagination to compensate for this flaw which helps it in the form of mystical intuition. Therefore, reason is not in contradiction with imagination and mystical intuition but mystical intuition grows with the help of reason and imagination

Comparison between neural network and P&O method in optimizing MPPT control for photovoltaic cell

The demand for renewable energy has increased because it is considered a clean energy and does not result in any pollution or emission of toxic gases that negatively affect the environment and human health also requiring little maintenance, and emitting no noise, so it is necessary to develop this type of energy and increase its production capacity. In this research a design of maximum power point tracking (MPPT) control method using Neural Network (NN) for photovoltaic system is presented. First we design a standalone PV system linked to dc boost chopper with MPPT by perturbation and observation P&O technique, and then a design of MPPT by using ANN for the same system is presented. Comparative between two control methods are studied. The results explained in constant and adjustable weather settings such as irradiation and temperature. The results exposed that the proposed MPPT by ANN control can improve the PV array efficiency by reduce the oscillation around the MPP that accure in P&O method and so decreases the power losses. As well as decrease the the overshot that accure in transient response, and hence improving the performance of the solar cell