19672 research outputs found
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Designing infographics for the educational technology course: Perspectives of preservice science teachers
No full textDespite the existing research on technology use in tertiary education, there is limited scholarly literature on the use of infographics in education or on the effective design of infographics specifically for educational settings. By employing qualitative research, the researcher attempts to explore the learners’ perception of the use of infographics. This research involved the researcher working independently on an in-class research project with 40 third-year undergraduate students. The pre-service science teachers were required to individually create an infographic related to the upper secondary school science curriculum. The findings indicated that the pre-service teachers expressed positive viewpoints about the infographics assignment. When the pre-service teachers were engaged in the learning process, they had a sense of agency and responsibility for their learning. The findings also indicated that this research created a meaningful experience for the pre-service teachers in engaging technology. This research essentially promoted innovations in teaching and learning of the course that encouraged student engagement with technology
Draft Genome Sequence of a Vibrio parahaemolyticus Strain, KS17.S5-1, with Multiple Antibiotic Resistance Genes, Which Causes Acute Hepatopancreatic Necrosis Disease in Penaeus monodon in the West Coast of Peninsular Malaysia
No full textWe report the first draft genome sequence of a Vibrio parahaemolyticus strain (VpAHPND), which causes acute hepatopancreatic necrosis disease (AHPND) in Penaeus monodon. The strain has a pVA1-like plasmid carrying pirAvp and pirBvp genes. Whole-genome comparisons revealed 98% similarity to VpAHPND isolates from Thailand, Mexico, and Vietnam
Host mobility key management in dynamic secure group communication
No full textThe key management has a fundamental role in securing group communications taking place over vast and unprotected networks. It is concerned with the distribution and update of the keying materials whenever any changes occur in the group membership. Wireless mobile environments enable members to move freely within the networks, which causes more difficulty to design efficient and scalable key management protocols. This is partly because both member location dynamic and group membership dynamic must be managed concurrently, which may lead to significant rekeying overhead. This paper presents a hierarchical group key management scheme taking the mobility of members into consideration intended for wireless mobile environments. The proposed scheme supports the mobility of members across wireless mobile environments while remaining in the group session with minimum rekeying transmission overhead. Furthermore, the proposed scheme alleviates 1-affect-n phenomenon, single point of failure, and signaling load caused by moving members at the core network. Simulation results shows that the scheme surpasses other existing efforts in terms of communication overhead and affected members. The security requirements studies also show the backward and forward secrecy is preserved in the proposed scheme even though the members move between areas
Numerical Study of Conventional and Biomimetic Marine Current Turbines in Tandem by Using Openfoam®
No full textThe increasing demands on renewable energy nowadays caused the development of marine current turbine industry. In order to improve the current design of marine current turbines, studies were conducted to analyse their hydrodynamic performances during operation. Since most of the time marine current turbines operate in arrays, it is important to understand the interactions between the turbines in order to design the optimum turbine farm. OpenFOAM® was used to simulate the turbine interactions of conventional and biomimetic marine current turbines in tandem configuration. The conventional marine current turbines were referred to Pinon et al. (2012) and Mycek et al. (2013) while the biomimetic marine current turbine was adopted from Chu (2016). The numerical simulations were conducted with turbines in different inter-device distances, A/D. The percentage differences of ''efficiency'', η between the IFREMER-LOMC and the biomimetic turbine case of inter-device distances, A/D = 4, 6, 8 and 10 are 14.3%, 6.4%, 3% and 1.92% respectively. The results show that the power produced by the biomimetic turbines in tandem is comparable with the IFREMER-LOMC turbines when A/D > 4. The biomimetic marine current turbines can be a fair choice due to their potential to have alternative fabrication method of their sheet-like turbine blades
Trade versus riba in the Qurʾān with a critique of the role of bank-saving
No full textPurpose: This paper aims to explain the dynamics of the inner inter-variable functional relations of trade versus oppositely coterminous variables of interest rates as shadow rates of interest. Such an explanation of trade versus riba relations has not been covered in the literature on Islamic economics and finance. Furthermore, the consequences of understanding the trade vs riba rule in relation to the bank-saving function remains absent in the literature. This problem as an important one between trade-interest rate and bank-savings interrelationship is studied. An empirical explanation is given besides the analytical explanation. This paper therefore presents an original and substantive topic to study. Design/methodology/approach: The avoidance of usury and financial interest have equivalent injunction in the Qur’an by the riba rule. To attain and implement the riba-avoidance rule, it is necessary to understand this rule in terms of its adverse relationship; and contrarily by the positively complementary interrelationship between trade, money, finance and the real economy under the impact of the riba rule. In explaining such inter-causal relationships, certain analytical matters stand out as key points. These are studied in the light of the Islamic methodological basis of the ontological law of participatory oneness as monotheistic unity of knowledge and its impact on the understanding of the trade versus riba and bank-savings rule. Findings: First, bank-savings cause withdrawal of resource mobilization and thus rupture the positive complementarities between the purpose and objective of the Shari’ah (maqasid-as-shari’ah) variables. Second, to deeply understand the rule of establishing trade versus the practice of riba (financial interest) and the needed theory of complementary inter-variable relationships to enable the relationship of trade versus riba, it is fundamentally necessary to understand the Qur’anic epistemological premise of Tawhidi unity of knowledge as organic unity and its induction in the generality and details of the problems under study. Originality/value: Such an explanation of trade versus riba relations with the instrument of bank-savings has not been covered in the literature on Islamic economics and finance. It is therefore an original and substantive issue to study
The Effects of Chinese Herbal Medicines on the Quorum Sensing-Regulated Virulence in Pseudomonas aeruginosa PAO1
No full textThe quorum sensing (QS) system has been used by many opportunistic pathogenic bacteria to coordinate their virulence determinants in relation to cell-population density. As antibiotic-resistant bacteria are on the rise, interference with QS has been regarded as a novel way to control bacterial infections. As such, many plant-based natural products have been widely explored for their therapeutic roles. These natural products may contain anti-QS compounds that could block QS signals generation or transmission to combat QS pathogens. In this study, we report the anti-QS activities of four different Chinese herbal plant extracts: Poria cum Radix pini, Angelica dahurica, Rhizoma cibotii and Schizonepeta tenuifolia, on Pseudomonas aeruginosa PAO1. All the plants extracted using hexane, chloroform and methanol were tested and found to impair swarming motility and pyocyanin production in P. aeruginosa PAO1, particularly by Poria cum Radix pini. In addition, all the plant extracts also inhibited violacein production in C. violaceum CV026 up to 50% while bioluminescence activities were reduced in lux-based E. coli biosensors, pSB401 and pSB1075, up to about 57%. These anti-QS properties of the four medicinal plants are the first documentation that demonstrates a potential approach to attenuate pathogens’ virulence determinants
Ambient RF energy harvesting system: a review on integrated circuit design
No full textThis paper presents a comprehensive review of ambient RF energy harvester circuitry working on integrated circuits. The review covers 3 main blocks in an RF energy harvesting system implemented on chip. The blocks are the rectifier, impedance matching circuit and power management unit. The review of each block includes its operational principle, reported state-of-the-art circuit enhancement techniques, and design trade-offs. We compare the circuits in each block with respect to the techniques adopted to improve the performances for RF energy harvesting. To identify the benefits and limitations associated with the architecture we discuss the advantages and disadvantages of the circuit topologies in each block of an ambient RF energy harvester
Reaction-diffusion kinetics on lattice at the microscopic scale
No full textLattice-based stochastic simulators are commonly used to study biological reaction-diffusion processes. Some of these schemes that are based on the reaction-diffusion master equation (RDME) can simulate for extended spatial and temporal scales but cannot directly account for the microscopic effects in the cell such as volume exclusion and diffusion-influenced reactions. Nonetheless, schemes based on the high-resolution microscopic lattice method (MLM) can directly simulate these effects by representing each finite-sized molecule explicitly as a random walker on fine lattice voxels. The theory and consistency of MLM in simulating diffusion-influenced reactions have not been clarified in detail. Here, we examine MLM in solving diffusion-influenced reactions in three-dimensional space by employing the spatiocyte simulation scheme. Applying the random walk theory, we construct the general theoretical framework underlying the method and obtain analytical expressions for the total rebinding probability and the effective reaction rate. By matching Collins-Kimball and lattice-based rate constants, we obtained the exact expressions to determine the reaction acceptance probability and voxel size. We found that the size of voxel should be about 2% larger than the molecule. The theoretical framework of MLM is validated by numerical simulations, showing good agreement with the off-lattice particle-based method, enhanced Green's function reaction dynamics (egfrd). MLM run time is more than an order of magnitude faster than egfrd when diffusing macromolecules with typical concentrations observed in the cell. MLM also showed good agreements with egfrd and mean-field models in case studies of two basic motifs of intracellular signaling, the protein production-degradation process and the dual phosphorylation-dephosphorylation cycle. In addition, when a reaction compartment is populated with volume-excluding obstacles, MLM captures the nonclassical reaction kinetics caused by anomalous diffusion of reacting molecules
Rapid synthesis of nanocrystalline zeolite W with hierarchical mesoporosity as an efficient solid basic catalyst for nitroaldol Henry reaction of vanillin with nitroethane
No full textZeolite W nanorods (MER topology) containingK+ cation (K-W) has been synthesized for the first time without the use of organic structure-directing-agent (OSDA). With microwave heating, the synthesis time can be shortened to 12 min, which is much shorter than the time required by conventional method (10 days, 150o C). The study reveals that the use of basic synthesis condition and K+ as the cation source are essential in order to produce zeolite W nanocrystals. The K-W displays bundle-like nanorods morphology with highly accessible hierarchical mesoporosity. The nanocrystals are colloidal stable in water and contain large amount of extraframework K+ cations. The K-W has demonstrated very good performance as a recyclable base catalyst in Henry (nitroaldol) reaction of vanillin with nitroethane (conversion 86.5%)
Synthesis and anticancer activity of novel water soluble benzimidazole carbamates
No full textMetastases account for more than 90% of all cancer deaths and respond poorly to most therapies. There remains an urgent need for new therapeutic modalities for the treatment of advanced metastatic cancers. The benzimidazole methylcarbamate drugs, commonly used as anti-helmitics, have been suggested to have anticancer activity, but progress has been stalled by their poor water solubility and poor suitability for systemic delivery to disseminated cancers. We synthesized and characterized the anticancer activity of novel benzimidazoles containing an oxetane or an amine group to enhance solubility. Among them, the novel oxetanyl substituted compound 18 demonstrated significant cytotoxicity toward a variety of cancer cell types including prostate, lung, and ovarian cancers with strong activity toward highly aggressive cancer lines (IC50: 0.9–3.8 μM). Compound 18 achieved aqueous solubility of 361 μM. In a mouse xenograft model of a highly metastatic human prostate cancer, compound 18 (30 mg/kg) significantly inhibited the growth of established tumors (T/C: 0.36) without noticeable toxicity