Over-expression of a cyanobacterial gene for 1-deoxy-D-xylulose-5-phosphate synthase in the chloroplast of Chlamydomonas reinhardtii perturbs chlorophyll: carotenoid ratios

Terpenoids are a diverse class of naturally occurring compounds consisting of more than 50,000 structurally different molecules and are found in all living organisms. Many terpenoid compounds, in particular those isolated from plants, have applications in various commercial sectors including medicine, agriculture and cosmetics. However, these high value terpenoids are produced in relatively small quantities in their natural hosts and their chemical synthesis for large scale production is costly and complicated. Therefore, there is much focus on producing these compounds in novel biological hosts using metabolic engineering technologies. As a photosynthetic system, the unicellular green alga C. reinhardtii is of particular interest as the most well-studied model alga with well-established molecular tools for genetic manipulation. However, the direct manipulation of terpenoid biosynthetic pathways in C. reinhardtii necessitates a thorough understanding of the basic terpenoid metabolism. To gain a better understanding of the methylerythritol phosphate (MEP) pathway that leads to terpenoid biosynthesis in the chloroplast of C. reinhardtii, hence this study has investigated the effect of over-expressing 1-deoxy-D-xylulose-5-phosphate synthase (DXS) on plastidic downstream terpenoids. We produced marker-free chloroplast transformants of C. reinhardtii lines that express an additional cyanobacterial gene for DXS. The analysis of terpenoid content for the transgenic line demonstrates that overexpressing DXS resulted in a two-fold decrease in the chlorophyll levels while carotenoid levels showed variable changes: zeaxanthin and antherxanthin levels increased several-fold, lutein levels dropped to approximately half, but β-carotene and violaxanthin did not show a significant change

Metabolic engineering of the algal chloroplast for terpenoid production

Microalgal biotechnology has attracted considerable interest owing to it is potential to provide renewable energy and its capacity to produce molecules such as pigments, fatty acids and other high value compounds, which can be used in the biomaterials, cosmetics and pharmaceutical industries. One class of compounds are the terpenoids: a diverse group of molecules derived from C5 isoprene units that are exploited for their aromatic and bioactive properties. Terpenoid production in microalgae offers an alternative to extraction from plant species or chemical synthesis. However, metabolic engineering technology for microalgae is still in its infancy and far from economic viability. Thus, the aim of this study was to develop engineering tools for the industrial algal species Nannochloropsis gaditana, with the goal of manipulating the main terpenoid pathway located in the chloroplast. In parallel, the effects of such manipulation was studied using the laboratory species Chlamydomonas reinhardtii, for which chloroplast genetic engineering is already established. N. gaditana is a robust marine species well suited to industrial scale cultivation. The availability of a draft genomic sequence, nuclear transformation methodology and a high lipid productivity have positioned N. gaditana as a promising oleaginous alga for metabolic engineering. However, to develop it as an industrially relevant platform, further molecular tools are needed; in particular a reliable chloroplast transformation method. Thus, the aim of the first project was to develop chloroplast transformation for the alga. This involved optimizing the cultivation conditions for N. gaditana, evaluating its sensitivity to herbicides and chloroplast specific compounds in order to identify suitable selectable markers, and to construct chloroplast transformation vectors. In addition, the temporary increase in cell size by inhibition of cytokinesis was investigated in order to facilitate the delivery of DNA into the small chloroplast. C. reinhardtii is the most developed algal model with well-established tools for genetic manipulation, and can be used to study the effect of chloroplast metabolic engineering in other species such as Nannochloropsis. Thus, the second project focused on the manipulation of the terpenoid biosynthetic pathway: specifically, the chloroplast-localized methylerythritol phosphate pathway by over-expressing the rate limiting enzyme; 1-deoxy-D-xylulose-5-phosphate synthase (DXS). An additional dxs gene from the cyanobacterium Synechocystis 6803 was introduced into the chloroplast genome in the hope of improving the productivity of downstream terpenoid metabolites. A number of transgenic lines were obtained and the successful integration was confirmed by molecular analysis. The effects of up-regulating DXS enzyme activity on overall algal growth and terpenoid profile are studied

The Need for Harmonizing Value Added Tax Legislation in Gulf Cooperation Council

The elimination of discriminatory value added tax (VAT) laws on commodities are required for the proper function of the Gulf Cooperation Council (GCC) single market. The proper function of a single market entails the elimination of discriminatory internal VAT regulations of imported goods or services. Hence, the purpose of this study is to empirically examine the need for harmonizing VAT legislation among GCC countries. The data of this study was collected through a variety of sources, including the ministry's website, VAT law for each country, published articles, and other online data sources/websites with regards to VAT. The data were statistically evaluated using Microsoft Excel. The dependent variable in this study is Harmonization. The factors affecting Value Added Tax Legislation are also called independent variables. Through this search, they harmonize VAT legislation in the GCC countries to maximize the effectiveness of tax laws. Thus, such a fact process to be helpful to understand the challenges faced by GCC companies due to discriminatory VAT regulations and double taxation.  There is a need to harmonize VAT legislation in the GCC countries to maximize the effectiveness of tax laws. This study adds value by assessing the present state and the need for harmonizing VAT legislation in the GCC countries. The timely approach of the study will help policymakers, regulators, and practitioners to understand the importance of harmonizing VAT legislation in the GCC

Semi-automated assessment of tree diagrams

The large number of students enrolling in higher education courses at many institutions has fuelled the need for automated assessment system tools. Diagrammatic solutions are an integral aspect of many courses in higher education, such as software design and data structures courses. With such a large number of students needing to be taught and assessed, there is a growing need for educators to consider models of assessment beyond those which traditional methods allow. Currently, computer aided assessment systems are extensively used for marking objective questions. There is a need to develop tools that can assess students’ knowledge in a comprehensive way, such as through assessment of diagrammatic solutions. The primary aim of this research is to investigate a new approach of assessment that enables the use of computers to support the assessment process of tree structures. [Continues.

In-network database query processing for wireless sensor networks

In the past research, smart sensor devices have become mature enough for large, distributed networks of such sensors to start to be deployed. Such networks can include tens or hundreds of independent nodes that can perform their functions without human interactions such as recharging of batteries, the configuration of network routes and others. Each of the sensors in the wireless sensor network is considered as microsystem, which consists of memory, processor, transducers and low bandwidth as well as a low range radio transceiver. This study investigates an adaptive sampling strategy for WSS aimed at reducing the number of data samples by sensing data only when a significant change in these processes is detected. This detection strategy is based on an extension to Holt's Method and statistical model. To investigate this strategy, the water consumption in a household is used as a case study. A query distribution approach is proposed, which is presented in detail in chapter 5. Our developed wireless sensor query engine is programmed on Sensinode testbed cc2430. The implemented model used on the wireless sensor platform and the architecture of the model is presented in chapters six, seven, and eight. This thesis presents a contribution by designing the experimental simulation setup and by developing the required database interface GUI sensing system, which enables the end user to send the inquiries to the sensor s network whenever needed, the On-Demand Query Sensing system ODQS is enhanced with a probabilistic model for the purpose of sensing only when the system is insufficient to answer the user queries. Moreover, a dynamic aggregation methodology is integrated so as to make the system more adaptive to query message costs. Dynamic on-demand approach for aggregated queries is implemented, based in a wireless sensor network by integrating the dynamic programming technique for the most optimal query decision, the optimality factor in our experiment is the query cost. In-network query processing of wireless sensor networks is discussed in detail in order to develop a more energy efficient approach to query processing. Initially, a survey of the research on existing WSN query processing approaches is presented. Building on this background, novel primary achievements includes an adaptive sampling mechanism and a dynamic query optimiser. These new approaches are extremely helpful when existing statistics are not sufficient to generate an optimal plan. There are two distinct aspects in query processing optimisation; query dynamic adaptive plans, which focus on improving the initial execution of a query, and dynamic adaptive statistics, which provide the best query execution plan to improve subsequent executions of the aggregation of on-demand queries requested by multiple end-users. In-network query processing is attractive to researchers developing user-friendly sensing systems. Since the sensors are a limited resource and battery powered devices, more robust features are recommended to limit the communication access to the sensor nodes in order to maximise the sensor lifetime. For this reason, a new architecture that combines a probability modelling technique with dynamic programming (DP) query processing to optimise the communication cost of queries is proposed. In this thesis, a dynamic technique to enhance the query engine for the interactive sensing system interface is developed. The probability technique is responsible for reducing communication costs for each query executed outside the wireless sensor networks. As remote sensors have limited resources and rely on battery power, control strategies should limit communication access to sensor nodes to maximise battery life. We propose an energy-efficient data acquisition system to extend the battery life of nodes in wireless sensor networks. The system considers a graph-based network structure, evaluates multiple query execution plans, and selects the best plan with the lowest cost obtained from an energy consumption model. Also, a genetic algorithm is used to analyse the performance of the approach. Experimental testing are provided to demonstrate the proposed on-demand sensing system capabilities to successfully predict the query answer injected by the on-demand sensing system end-user based-on a sensor network architecture and input query statement attributes and the query engine ability to determine the best and close to the optimal execution plan, given specific constraints of these query attributes . As a result of the above, the thesis contributes to the state-of-art in a network distributed wireless sensor network query design, implementation, analysis, evaluation, performance and optimisation

Isolation, characterization and standardization of demineralization process for chitin polymer and minerals from the crabs waste of Portunidae segnis

The most abundant polymeric compound in nature after cellulose is chitin. Mostly, it is used as raw material for food additives, agriculture, biomedicine, water treatment, cosmetics and textile industry. Exoskeletons of crustaceans such as lobster, crabs and shrimps, mollusks, insects and the cell walls of certain fungi are the main sources of chitin. The best raw material for the production of chitin is marine exoskeletons. The current objective of this study is to standardize the demineralization process for removal of minerals from the waste of Portunidae segnis (P. segnis) by using chemical treatment. A fix concentration of HCl acid at various reaction conditions are used in the demineralization process for the first step of chitin isolation. The percentage of calcium and phosphorous removed after demineralization process was determined by using sensitive Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The P. segnis was purchased from a local market, it was collected from the coastal area of Oman. The samples were dried and ground into coarse powder. The coarse powdered samples were treated with 2 M concentration of hydrochloric acid at different incubation time, temperature and weight/volume ratio. All treated samples were analyzed by using sensitive ICP-OES. The results from the ICP-OES showed that treatment of P. segnis waste samples with 2 M of HCl at room temperature for 70 min with ratio of 1:20 (w/v) is the best process for demineralization of chitin. FT-IR, SEM/EDX and ICP-OES analysis of this sample confirmed successful isolation of minerals from Omani P. segnis. In conclusion, the best standardized demineralization process could be used for the isolation of good quality of chitin. This chitin could be used as the main raw material in food industry, agriculture, biomedicine, cosmetics and textile industry

Marketing Potential of Homemade Food: a New Entrepreneurial Endeavour

This study aims to examine the marketability of homemade food and to understand the need for an entrepreneurial venture start-up in Oman. In addition, it explores barriers to buying or selling homemade food. The research is based on a qualitative study using purposive sampling techniques by an indepth interview with 83 aspirant buyers and sellers of homemade food. The study’s findings confirm that the marketability of homemade food can be achieved by developing a unique application for trading these products, that will help to avoid barriers to buying or selling. Most respondents preferred eating homemade food rather than restaurant or commercially prepared food. These research findings provide entrepreneurs with some insight in terms of new venture start-ups for marketing homemade food in niche markets. This research comprises a specific approach to the marketability of homemade food and suggests a unique mobile app for trading homemade food. The data was gathered in Nizwa, Oman, however it could be broadened to encompass more geographic regions, particularly urban areas. The research results, achieved using qualitative methodologies, contribute significantly to the body of existing literature. It enhances value in analysing probable barriers among aspirant buyers and sellers of homemade food

Marketing Potential of Homemade Food: a New Entrepreneurial Endeavour

This study aims to examine the marketability of homemade food and to understand the need for an entrepreneurial venture start-up in Oman. In addition, it explores barriers to buying or selling homemade food. The research is based on a qualitative study using purposive sampling techniques by an indepth interview with 83 aspirant buyers and sellers of homemade food. The study’s findings confirm that the marketability of homemade food can be achieved by developing a unique application for trading these products, that will help to avoid barriers to buying or selling. Most respondents preferred eating homemade food rather than restaurant or commercially prepared food. These research findings provide entrepreneurs with some insight in terms of new venture start-ups for marketing homemade food in niche markets. This research comprises a specific approach to the marketability of homemade food and suggests a unique mobile app for trading homemade food. The data was gathered in Nizwa, Oman, however it could be broadened to encompass more geographic regions, particularly urban areas. The research results, achieved using qualitative methodologies, contribute significantly to the body of existing literature. It enhances value in analysing probable barriers among aspirant buyers and sellers of homemade food

Development of a Citric-Acid-Modified Cellulose Adsorbent Derived from Moringa peregrina Leaf for Adsorptive Removal of Citalopram HBr in Aqueous Solutions

A citric-acid-modified Moringa peregrina leaf substrate was prepared and studied as an effective adsorbent for the adsorptive removal of citalopram HBr (CTM). FTIR spectra were utilized to characterize the prepared solid. The effects of experimental variables on the percentage removal of citalopram HBr were investigated using response surface methodology. The optimum conditions selected for removal of CTM were 7 and 4 min, 0.17 g per 50 mL and 35 mg·L−1 for pH, contact time, adsorbent dose and initial concentration of CTM, respectively. Under the optimized experimental conditions, 82.59% CTM (35 mg·L−1) was removed. The Langmuir isotherm, Freundlich isotherm, pseudo second-order kinetic model and diffusion-chemisorption model explained the adsorption data successfully. The maximum adsorption capacity at 298 K was 8.58 mg·g−1. A thermodynamic study illustrated that CTM adsorption was spontaneous and endothermic in nature

Box–Behnken design based development of UV-reversed phase high performance liquid chromatographic method for determination of ascorbic acid in tablet formulations

A simple, sensitive, accurate and inexpensive UV-reversed-phase high-performance liquid chromatographic method was developed for the determination of ascorbic acid in tablet formulations. The method was based on the separation of ascorbic acid using a mobile phase of an acetonitrileNaH2PO4 -H3PO4 buffer solution (pH = 3) (5:95 v/v) with a UV detection wavelength of 245 nm and a flow rate of 0.8 mL min−1 at ambient column temperature. The variables of the proposed method, such as acetonitrile fraction (%), flow rate (mL min−1 ) and column temperature (◦C), were optimized on the peak area by response surface methodology via the Box–Behnken design. The mobile phase was passed isocratically, and the separation of ascorbic acid was performed at the retention time of 4.1 min. A calibration graph was obtained and found to be linear in the concentration range of 10–180 µg mL−1 . The method suitability was assessed and an asymmetry factor of 1.15 was obtained. The proposed method was successfully applied for the determination of ascorbic acid in tablet formulations and statistically compared with the results of the reference method. The performance of the proposed method was excellent and in agreement with the reference method. The recovery percentage of the proposed and reference methods was in the range of 99.98–100.04% and showed compliance (100 ± 2%) with regulatory guidelines