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Comparison of three analytical techniques for general characterisation of selected algae and cyanobacteria / Suhaina Nashath Mohamed Iqbal
No full textAlgae and cyanobacteria maintain the oxygenation of earth, and are utilised as biofuels, biofertilizers and nutrition feed. The characterisation of algae and cyanobacteria through conventional methods require technical expertise, laborious sample preparation, and moderately expensive instruments and reagents. Hence, in this study, selected bioanalytical techniques with minimal sample preparation were incorporated, to simplify the characterisation of algae and cyanobacteria. The objectives of this research were to study the phylogenetic relationship of the selected algae and cyanobacteria via the 23S plastid ribosomal ribonucleic acid (rRNA) and 18S rRNA biomarkers; to validate the presence of the microcystin synthetase (mcy) gene cluster encoding the biosynthesis of microcystin in the selected cyanobacteria; to identify the organic compounds present in the selected algae and cyanobacteria via gas chromatography-mass spectrometry (GCMS); and to study the vibrational properties exhibited by the atom of the selected algae and cyanobacteria via Raman spectroscopy. Pure cultures of the selected algae and cyanobacteria were sourced from the culture collection centre. The deoxyribonucleic acid (DNA) of algae and cyanobacteria was extracted following the phenol-chloroform protocol, and subjected to the polymerase chain reaction (PCR) using the 23S plastid rRNA (p23SrV) biomarker. The taxonomic clade of brown algae (Chaetoceros calcitrans and Isochrysis galbana), green algae (Chlorella spp. and Tetraselmis spp.), and cyanobacteria (Microcystis aeruginosa and Nostoc spp.), were distinguished. This universal biomarker simplified the taxonomic classification of both algae (eukaryotic) and cyanobacteria (prokaryotic). Whereas, the 18S rRNA (18Sr) biomarker shows a further separation of C. calcitrans and I. galbana into two different clades, and green algae as a single clade. Furthermore, the mcy gene cluster was not expressed in both of the cyanobacteria species. In addition, in GC-MS analysis, the organic phase of algae and cyanobacteria was extracted via solvent extraction, prior to injecting in the Agilent 6890N Network GC system. The organic compounds, namely alkane, alkyne, alcohol, phenol, polycyclic hydrocarbon, aromatic ketone, and siloxane were eluted, based on its polarity and volatility properties. These compounds are bio-commercialised as biofuels, cosmetics and skincare, industrial polymers and lubricants, paint coatings, and paraffin waxes. Lastly, a thin film of air-dried algae and cyanobacteria were analysed in Renishaw In Via Raman Microscope. The Raman spectra produced corresponded with saffron and
carotene photosynthetic pigments, at peaks 1010 cm-1, 1155 cm-1 and 1520 cm-1. These pigments can be extracted from algae and cyanobacteria, and bioengineered for industrial use. Briefly, this research serves as a baseline study for environmental monitoring and a quick approach to identify compounds, that are beneficial as biofuels and pharmaceutical products in the future. Freshwater algae and cyanobacteria could be a fundamental source for farmers to harvest, and convert waste materials to useful materials. Algae blooms which are potential biotoxins for fishes and prawns, can now be converted sustainably, in-line to convert waste to wealth strategy
A morphological analysis of Lun Bawang / Shalini Mugundan
Get PDFLinguists generally acknowledge that there exists an inevitable inter-relationship between different levels of linguistic analysis; phonetics, phonology, morphology, syntax, and semantics. Various linguistic labels are used to describe such a link. In particular, there exists a bridge between the phonology and morphology of particular languages. The term morphophonemic is generally used to describe linguistic statements that can be made of the phonemic structure of morphemes and their effect on the grammatical content of languages. This research attempts a morphophonemic analysis in one Austronesian language which is known as Lun Bawang, a language own by Lun Bawang or Murut community in the Sarawak region. This language also falls under one of the endangered languages in the Brunei region. The research has been conducted by analyzing the morphological processes involved in this language. The lexical categories or word classes have been identified and used as the medium of analysis. Besides, this research has also been a bridge to see the morphological patterns of Lun Bawang with the reference of bahasa Melayu as bahasa Melayu is the main language under the Austronesian family. The data have been analyzed by doing broad transcription. The result indicates that Lun Bawang has quiet similar morphological patterns as bahasa Melayu as most of the words are seen to be used in both languages. On the other hand, Lun Bawang has been identified to have a few morphological processes such as affixation and reduplication and phonemically has some similarities whereby bahasa Melayu has undergone complete transfer, partial transfer, transfer with sound changes, and few more components to fit Lun Bawang sound system. Overall, Lun Bawang is a language that also falls under the Austronesian family as similarities could be seen with bahasa Melayu and it has a few morphological processes involve. Besides, findings also show that Lun Bawang is still being used by the community but some components of endangered language could be seen as most of the people are moving towards official languages which are bahasa Melayu and English
Ultra-wideband power amplifier design for large signal application / Ragavan Krishnamoorthy
Get PDFBroadband power amplifier design has become one of the most critical enabling block in today’s wireless communication technology. Numerous research efforts have been carried out throughout the years to establish high efficiency over wideband RF transmitter. This research work presents two approaches in achieving ultra-broadband power amplifier for RF transmitter. Firstly, a new technique for the design of ultra-broadband RF power amplifier is introduced, in which a combination of the reactance compensation and third-harmonic tuning are adopted. The design goal is to achieve 40 dBm (10W) output power across a wide frequency bandwidth operation. Theoretical design equations were developed to enable a designer to replicate the amplifier in the need of a highlighted specifications. The experimental result shows high efficiency achievement, more than 60%, throughout a wide bandwidth between 0.4 - 2.0 GHz. Another new design technique for broadband RF power amplifier is introduced for second approach, with combination of large signal X-parameter and Real-Frequency Technique (RFT). A theoretical analysis of large signal X-parameter is revisited, and a simplification method is introduced to determine the optimum large signal impedances of GaN HEMT device in use. With the optimum impedance extraction over the wide frequency range (0.3 - 2.0 GHz), a wideband matching network is constructed employing RFT and the final design is implemented with practical mixed-lumped elements. The prototype broadband RF PA demonstrates an output power of 40 dBm (10 W). The average drain efficiency of the PA is found to be more than 60% over the frequency band of (0.3- 2.0 GHz). These techniques demonstrated small size area and lower cost implementation which are suitable for RF communications applications
Synthesis of polyurethane incorporated by calcium oxide and magnesium oxide for heavy metal removal from water / Mohsen Vafaei Fard
Get PDFWater contaminated by heavy metals such as copper, lead, nickel, and cadmium has significant adverse impacts on receiving water. In recent years, various methods, such as adsorption, chemical precipitation, and ion exchange, have been extensively studied for the elimination of heavy metals. Adsorption is one of the numerously and diversely reported mechanisms of removing heavy metals due to its simplicity and costeffectiveness. In this study, highly permeable rigid polyurethanes (PU) incorporating calcium oxide (CaO) (PU/CaO) composite materials were prepared via a facile and economic one-pot synthesis method and characterized for remediation of heavy metal from water. To investigate the effect of CaO on heavy metal adsorption, the amount of CaO was varied from 0 to 25 of total weight (wt.%) of polyol and Methylene diphenyl diisocyanate (MDI). Among the media tested, 25% CaO-incorporated PU (PU/CaO-25) had the highest adsorption capacity (Qmax = 35.6 mg.g-1) of Cu(II). The PU/CaO-25 is capable of removing Cu(II), Pb(II), Zn(II), and Ni(II) ions by both adsorption and ion exchange mechanisms. However, precipitation was the dominant mechanism for removal of metal ions due to the increase of pH in the solutions. Moreover, column tests were conducted to investigate various parameters, and data were interpreted using the Bed Depth Service Time (BDST) model to predict service time. Specific structural features of PU/CaO-25 and the remediation mechanism were also determined using FESEM/EDS, XRD, N2 gas isotherm, and chemical equilibrium modeling. Moreover, column tests using simulated urban storm-water runoff (USR) showed that PU/CaO-25 removed all heavy metals such as Cu(II), Zn(II), Ni(II), and Pb(II) to below their regulation levels at~1,100-bed volumes (BVs). In the second stage of this research to enhance the removal efficiency of heavy metals by using PU, commercial MgO was used, and a simple hydrothermal method was applied to the mixture of commercial MgO and granular PU (gPU). Three-dimensional (3D) flowerlike Mg(OH)2 structures (FMH) were built on the surface of gPU (gPU-FMH). Hydrothermal process and gPU was the key factors for the assembly of the FMH. The synthesized hexagonal nanosheet petals of gPU-FMH provided a high surface area. The gPU-FMH showed the superb adsorption capacity (Qmax = 472, 1050, and 1293 mg.g-1 for Cu(II), Cd(II), and Pb(II), respectively). The proposed hypothesis for the synthesis of gPU-FMH and the removal mechanism of the heavy metals has been proved through various spectroscopic analyses. It was found that Mg(OH)2 dissociation in the metal solution produces two OH- ions that subsequently react with the metal ions. Based on the stoichiometry, this reaction can render the production of insoluble precipitates through coupling with the anionic species that exist in the solution. Further, the precipitates will become trapped in the gaps of the FMH particles, and the precipitation might be the dominant removal mechanism at the higher metal-ion concentrations. In the results of the continuous-flow column study, gPU-FMH showed a much higher removal capacity (184 mg.g-1) of Cu(II) than the other referenced media
The role of student engagement in the relationship between classroom motivation and academic achievement / Shailaja Damodaran
Get PDFThe aim of this study was to investigate undergraduate students’ perceived classroom motivation and perceived engagement in learning English course. It also examined the extent to which student engagement plays a mediating role in the relationship between classroom motivation and academic achievement. Using the Basic Needs Satisfaction at College Scale (Jenkins-Guarnieri et al., 2015) and Student Course Engagement Questionnaire (Handelsman et al., 2005), cross sectional surveys were conducted to collect data on classroom motivation and student engagement, respectively. Academic achievement was measured based on students’ course examination results. The sample comprised 137 undergraduate students from a public university in Malaysia. Data was analyzed using Statistical Package for the Social Sciences (SPSS) 22 and Structural Equation Modelling with SMART PLS 3. The findings showed that student engagement not only has direct relation to academic achievement, but also mediates the influence of classroom motivation on academic achievement. The results of this study encourage instructors to fulfil students’ intrinsic motivational needs in order to foster authentic engagement in learning, which in turn leads to improved academic gains. Limitation of this research is that the finding is only relevant to a specific class investigated during the time of study and the findings cannot be generalized to a larger population due to low number of participants. Future research may attempt to conduct longitudinal study to observe students’ motivation and engagement pattern throughout a semester and whether their level of motivation and engagement change over time
Metabolite profiling of Ganoderma-infected oil palm tree grown on ultisol and oxisol soil / Muhamad Fadhil Ahmad
Get PDFThe oil palm industry is a pillar of the Malaysian economy and plays a pivotal role in feeding and fueling a growing global population. In 2018, oil palm contributed 37.9% or RM37.7 billion to the country's' Gross Domestic Products (GDP) of agriculture sector. Despite achieving significant achievements in the industry, Ganoderma sp. infection that cause basal stem rot (BSR) and upper stem rot (USR) disease are considered a threat. The palm oil industry is expected to experience significant losses, thereby affecting yield production and ultimately the dead of trees. Some factors have been reported to affect the occurrence of the disease such as the cultivation of the previous crop, replanting technique, age and number of individual palms per planted area, type of soil series, inoculum potential, shading and soil temperature, but research conducted on weathered tropical soils in Malaysia is still lacking. In Malaysia, Ultisol and Oxisol soil are very common which occupy about 72% of the country’s land area. This research is therefore conducted with the objective to determine soil physicochemical properties of Ultisol and Oxisol soil and profile metabolites of healthy and Ganoderma-infected oil palm grown on both soils. Biological samples were extracted using methanol and analyzed by using liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS). Soil physicochemical properties analyzed using U-Mann Whitney revealed that Ultisol and Oxisol soil are different at pH and TC level but not for EC level. A chi-square test of independence classified Ultisol and Oxisol soil into sandy clay and clay respectively. For biological sample analysis, the initial Principal Component Analysis (PCA) model concluded that there was a difference between two main groups of metabolite profiles between healthy and Ganoderma-infected oil palm tree rachis samples. A strongly significant Partial Least Square-Discriminant Analysis (PLS-DA) model was acquired, indicating that the 12 biological variables indeed contained class separating information. The separation of the four classes was slightly superior compared with the previous PCA modelling attempts. This model also fits the criteria for validity in permutation test. From the model, 17 potential biomarker panels with variable importance in project (VIP) more than 2.00 and p-value of analysis of variance (ANOVA) less than 0.05 were identified. Among metabolite of interest putatively identified are choline phosphate, p-fluorophenylalanine, 2-oxoglutaramate, 4-oxoglutaramate, 4-amino-4-cyanobutanoic acid, 2-amino-4-cyanobutanoic acid, 5-aminolevulinate, L-allohydroxyproline and N-acetyl-beta-alanine. These findings are crucial for further study on the pathogenicity characteristic of BSR and USR disease in penetrating oil palm tree in the future
Fermented mycelial biomass of Ganoderma lucidum as a potential additive for juvenile red hybrid tilapia (Oreochromis sp.) / Kumeera Subramaniam
Get PDFThe presence of antibiotic compounds in aquaculture is gaining higher interest worldwide due to the emergence as dangerous pollutants of the environment and to human health. However, feed additive play an important role in agriculture to reduce the usage of antibiotics and aquaculture productive performance. Therefore, the polysaccharide produced by Ganoderma lucidum is recognised due to its essential biological activities. Growing biomass from mycelium of Ganoderma lucidum (MGL) through submerged liquid fermentation (SLF) has been a fast and straightforward alternative compared to fruiting bodies. The study aims to observe the inclusion of biomass from MGL as a dietary supplement on growth performance, antioxidant activity and fatty acid profile of red hybrid tilapia (Oreochromis sp) (RHTO). The experimental diets were 5g/kg, 10g/kg and 15g/kg of MB from MGL.Growth performance was measured using growth indicator parameters, antioxidant activity was measured for Glutathione S-Transferase (GST) and Catalase (CAT) while fatty acid profile was determine using the gas chromatography method. From the finding, the highest value for final weight and specific growth rate (SGR) was 35.4g and 2.14 in diet 15g/kg respectively. For feed conversion ratio (FCR) and feed intake (FI), the best result showed by 15g/kg diet. For antioxidants, the 10g/kg shows better results as GST (52.05nmol/mg protein) and CAT (169.04 nmol/min/ml) compared to other diets. There is no significant difference in 10g/kg diet compared to other diets. The finding on fatty acid profiling concludes that 10g/kg shows the best fatty acid profile for this study compared to control, 15g/kg and 5g/kg. Therefore, 10g/kg enhanced the survival, growth performance as well as antioxidant value. Since there is no mortality recorded, the study concludes that MB is a potential natural dietary supplement in the fish feed which helps promote growth and boost the antioxidant activity in fish
Design and development of a robotic platform for general neurosurgical procedures / Amir Hossein Mehbodniya
Get PDFFor the first time in 1985, robots were introduced to the neurosurgical operating rooms. Since then this field of robotics have advanced with new technologies with better accuracy and safety. However, developing robots for neurosurgery is a challenging task due to the sensitive nature of these applications and additionally their high cost of development. A typical neurosurgical robot costs millions of dollars in 2018, even though the costs of components and calculations have been lowered tremendously. This is mainly due to focus of current neurosurgical robots on few highly precise and specific surgical tasks which makes their use limited. In this thesis, development of a neurosurgical robot with a focus on more general surgical tasks related to surgical navigation is investigated, and its design and development are reported. Using this platform to develop more general surgical applications brings down the cost. Furthermore, this system has been developed using open source platforms that continually updates new features and technologies, helping this platform to stay up to date with current science of the day. To have a unified approach, three key phases had to be included. The first was the data collection and analysis, which involved collecting actual surgical data from live surgeries to analyze the workspace of the targeted surgical tasks which helped in structural design of the robot. The second was the design and development of the actual robot based on the initial analysis of the surgeries. In this work, the robot was designed to be small and dexterously suited to neurosurgical operating rooms. The third phase was the assessment of the robot’s function. Using any new device in actual surgeries requires a long track record of fault free operations. Therefore, the robot had to be validated using cadavers or animal subjects however, these methods also bring ethical, logistics and cost issues. So, a new approach was designed for assessment of the robot. This method involves using rapid prototyping techniques and actual patient data. In the process of this work, robotic applications had to be developed from scratch to enable the robot to perform surgical tasks and applications such as semi-automated patient-image registration, biopsy needle guidance and endoscope manipulation. Patient-image registration function matches the physical coordinates of the patient with medical image coordinates autonomously. Furthermore, biopsy needle guidance for brain tissue sampling is a common feature in neurosurgical robots, which enables a suitable benchmark for a robot’s accuracy. Endoscope manipulation is also a topic of interest in neurosurgery as it introduces different challenges compared to Laparoscopic surgeries. The robot performed with adequate accuracy for general surgical tasks, however, it showed some limitations in the endoscope manipulation features
Low-power cmos cross-coupled differential-drive rectifier for ambient radio frequency energy harvesting systems / Gabriel Chong Sing Leung
Get PDFWireless Sensor Node (WSN) for the Internet of Things (IoT) and Internet of Everything (IoE) will require harvesting low-power ambient Radio Frequency (RF) energy to achieve self-power capabilities, alleviating the need of batteries. The research title of “Low-Power CMOS Cross-Coupled Differential-Drive Rectifier for Ambient Radio Frequency Energy Harvesting Systems” relates to the design of integrated circuit (IC) rectifiers for low-power ambient RF energy harvesting (RFEH) in complementary-metal-oxide-semiconductor (CMOS) technology. The adoption of CMOS for the rectifier designs is to achieve small physical form factor, low-cost, and system-on-chip (SoC) integration. The rectifier is the main circuit in an ambient RFEH system to convert the scavenged RF power in alternating current (AC) into usable direct current (DC) for powering WSNs. The Cross-Coupled Differential-Drive (CCDD) rectifier is the selected choice in this thesis due to its high peak power conversion efficiency (PCE) and low sensitivity. However, the dynamic range (DR) efficiency of this topology restricts high-PCE-range performance due to the inherent low-power of ambient RF energy. The rectifier’s ability to convert ambient RF power into usable DC level present a bottleneck in achieving high PCE across input RF power range
Piet Mondrian’s neo-plastic compositions (1917-1944) and his six principles of neo-plasticism: An analysis of his aesthetic ideas based on a study of his essays and paintings / Ali Fallahzadeh
Get PDFAmongst the modern artists of the beginning of the 20th century, Dutch painter Piet Mondrian (1872-1944) is considered a pioneer of pure abstract painting. The result of his consistent intuitive experimentations on canvas during the 1910’s was the proposal of his new artistic style in 1919 called Neo-Plasticism, nieuwe beelding in Dutch. Throughout his Neo-Plastic period (1919-1944), he aimed to depict a universal expression of ‘equilibrium’ (new term for harmony) and a vital rhythm among his universal elements of painting called plastic means or means of imaging. Besides being a pure abstract painter, Mondrian was also a prolific writer of his theories. His theoretical writings, the majority of them written in the form of essays, articles, and notes, are indeed posterior outcome of his intuitive experimentations on his canvases. Scholars generally agree that his writings outline the evolution of his artistic vision of Neo-Plasticism. Considering the importance of Mondrian as an iconic pure abstract painter in the history of modern art, many scholars have emphasized on the contribution of this Dutch painter to modern art. However, previous researches did contextual analysis investigating his Neo-Plastic art and theory in relation to his artistic and philosophical influences such as De Stijl, Theosophy, Hegel, and Platonism. Contrary to the previous researches, this thesis looks at Mondrian’s writings and paintings, focusing on the evolution of his aesthetic ideas based on his artistic experimentation on the canvas. First, in order to explain the development of Mondrian’s artistic vision, his paintings were divided into three stylistic periods. Then, the important concepts of Neo-Plasticism found in his six principles of Neo-Plasticism are identified and compared to the paintings of the three periods. Secondly, the theoretical development of these concepts is analyzed, using both Mondrian’s paintings and texts, produced and written roughly at the same time. This thesis shows that a thorough examination of an experimental modern artists’ writings, like those of Mondrian, although difficult and complex, in parallel with a visual study of his artistic experimentation on the canvas can expand our understanding of their aesthetic evolution and bring something new to Art History of Modern Art