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Regulation of toll-like receptor-mediated innate immune response in chikungunya virus-infected and Fisetin-treated human hepatocellular carcinoma Huh7 cells / Rafidah Lani
No full textExcessive inflammation caused by chikungunya virus (CHIKV) infection is manifested
by incapacitating joint pain and prolonged arthritis in the chronic phase of CHIKV
infection. Arthritis resulted from a large influx of infiltrating immune cells driven by
pro-inflammatory cytokines and chemokines. Fisetin demonstrated anti-CHIKV activity
and has long been known to possess anti-inflammatory and immunomodulatory
properties. Modulating toll-like receptor (TLR)-mediated innate immune responses
might be one of the mechanisms utilized by fisetin against CHIKV infection. This study
was designed to assess fisetin capacity in modulating the TLR-mediated antiviral
responses against CHIKV in Huh7 cells. The hallmarks of inflammation and
cytopathological effects (CPE) were evaluated to test the hypothesis that fisetin
promotes TLR-mediated antiviral responses and limit CPE in CHIKV-infected Huh7
cells. CHIKV-induced CPE was observed using bright-field microscopy. Viral
infectivity was determined using a plaque-forming unit assay. CHIKV-E1 RNA copy
number and antiviral genes mRNA level were quantified using qRT-PCR. The
expression of TLR and CHIKV-E2 proteins was measured by performing an
immunofluorescence assay. The level of the inflammatory cytokines was determined
using a human cytokine array. The expression of the key transcription factors was
determined using immunoblot assay. The results showed that fisetin induced the
expression of the antiviral genes at an early time-point by promoting the
phosphorylation of IRF3 and IRF7 in CHIKV-infected Huh7 cells. Fisetin hindered
excessive inflammation in CHIKV-infected Huh7 cells by impeding
over-phosphorylation of NF-κB and reducing pro-inflammatory cytokines levels. Fisetin
also recovered Huh7 cells from CHIKV-induced CPE. The results also suggested that fisetin does not affect the level of the pro-and anti-inflammatory cytokines such as
IL-1α, IL-1β, IL-8, IL-10, IL-13, GM-CSF, GRO, MCP-1, MIP-1β, and RANTES; in
uninfected Huh7 cells. These suggested that fisetin is pharmacologically active only in
CHIKV-infected Huh7 cells and not uninfected cells. Findings from the study supported
the hypothesis that fisetin promotes antiviral responses and limit CPE in
CHIKV-infected Huh7 cells. Fisetin's balancing act in CHIKV-infected Huh7 cells was
subjected to fisetin modulating the key transcription factors manipulated by CHIKV
infection. On this basis, further research into fisetin in targeting host inflammation as a
therapeutic strategy is being considered
Experimental and numerical investigations of the compressive behavior of concretefilled steel tubular columns / Pouria Ayough
No full textDue to the advantages associated with the confinement effect provided by tubes in terms of improving the mechanical performance of concrete cast from waste material such as rubberized concrete (RuC), CFST and CFDST columns are excellent options for developing environmentally sustainable and economically viable structural members that aid in waste material recycling. The fundamental drawback of composite columns is tube buckling. The tube's buckling impairs the confinement effect and column ductility. Various forms of steel stiffeners have been used to increase the buckling resistance of tubes. Additionally, RuC's mechanical properties are predicted to increase the ductility of composite columns. However, little research has been undertaken on the influence of shear studs or RuC on the mechanical performance of composite columns. Various shapes of composite columns may be found worldwide, depending on aesthetics, specific architectural design styles, structural circumstances, and economic objectives. However, research comparing their structural performance with various forms is rare. This study investigates experimentally and numerically the performance of CFST and CFDST columns under axial compression. Experiments were conducted on eight axially loaded circular CFDST columns with and without bolted shear studs to determine the efficacy of bolted shear studs in enhancing their performance. Advanced FE models of CFDST columns with and without bolted shear studs were developed and validated by comparison with experimental results recorded in this research. Novel design models were recommended to predict the compressive capacities of circular CFDSTs with and without bolted shear studs. To examine the influence of cross-sectional forms on the structural performance of columns, FE models of CFSTs with circular and polygonal sections were generated. Following that, FE models of CFDST columns with normal concrete (NC) and RuC were generated. The validation of the FE simulation of CFSTs and CFDSTs with NC and RuC was made by comparing their predictions with the available experimental data. This research contributes to the knowledge by adding new experimental and FE test results on CFST and CFDST columns to the database. The numerical models developed provide researchers and structural designers with a deep understanding and accurate results, which lead to safer and more economical designs of composite structures. The experimental and numerical test results indicated the efficiency of bolted shear studs in improving the ductile performance of circular CFDSTs. The bolt spacing equivalent t
Analysis of yttria-stabilised zirconia and aluminium silicate coated piston crown on the engine performance with palm biodiesel / Navin Ramasamy
No full textIn this study, the effects of thermal barrier coatings (TBC) with yttria-stabilised zirconia
(Y2O3.ZrO2) and aluminium silicate (Al2O3.SiO2) with NiCrAl bond coatings on the engine
performance and emission were evaluated using conventional diesel and pure palm oil
biodiesel. These materials were coated on the piston crown using plasma spray coating. The
findings demonstrated that Y2O3.ZrO2 coatings presented better engine performances in
terms of brake thermal efficiency (BTE), and brake specific fuel consumption (BSFC) for
both fuels, which was much better than Al2O3.SiO2 coatings. The piston with Y2O3.ZrO2-
coated materials (P2D & P2B) achieved the highest BTE (15.94% for P2D, 14.55% for P2B),
and lowest BSFC (498.96 g/kWh for P2D, 619.81 g/kWh for P2B). However, Al2O3.SiO2
coatings indicated better emissions with the lower NO, CO, and CO2 emissions for both fuel.
It recorded the lowest HC emission due to complete combustion of the fuel in the engine.
Hence, it was concluded that the Y2O3.ZrO2 coating could lead to better engine performance.
At the same time, Al2O3.SiO2 showed promising low emissions in the first phase. TBC was
prepared using a series of mixtures consisting of different blend ratios of Y2O3.ZrO2 and
Al2O3.SiO2 via plasma spray coating. The experimental results showed that a TBC mixture
with 60% Y2O3.ZrO2 + 40% Al2O3.SiO2 had excellent NO and CO reductions compared to
the other blend coated pistons. The findings also indicated that the coating mixture with 50%
Y2O3.ZrO2 + 50% Al2O3.SiO2 had the highest BTE and lowest BSFC compared to all other
blend coatings. Blends coated with 50% Y2O3.ZrO2 + 50% Al2O3.SiO2 had the highest
performance, lowest emission, and highest durability for the diesel engine application. These
encouraging findings further proved the significance of TBCs in terms of enhancing the
engine performance and emission reductions operated with different types of fuels
Analytical hierarchical process of edible biomass as primary feedstocks in biodegradable plastic production / Ziwei Zhong
No full textPlastic is one of the world's most versatile materials due to its durability, stability, and low production costs. Plastics take an extremely long time to degrade and due to their widespread use, large amounts of plastic waste are released into the environment worldwide, which contributes to the current problem of white pollution. The waste plastics that accumulate in the environment can be further degraded by weathering into smaller pieces, such as microplastics and nanoplastics, but these small pieces can cause more harm to the environment than larger plastics. How to solve the environmental problems caused by plastics is a global topic and challenge. The production of biodegradable plastics, a countermeasure to the root cause, has become a hot topic of research in recent years. At present, biodegradable plastics are not an alternative to conventional plastics, as many different factors such as production costs, production processes, product properties, and the handling of biodegradable plastics are hindering the development of biodegradable plastics. Therefore, the selection of suitable raw materials is of paramount importance for the development and widespread use of biodegradable plastics. This study will begin with the selection of natural biomass resources for use as feedstock in the production of biodegradable plastics through an extensive literature search. Then various criteria influencing the selection of natural biomass were rated with the assistance of literature review. Finally, the most viable natural biomass was selected as a composite feedstock in the production of biodegradable plastics by using the Analytical Hierarchy Process (AHP). The results of the study showed that maize is the most favorable natural biomass for the production of biodegradable plastic
Investigation of nickel/cobalt-imidazolate based electrode for supercapacitor application / Atiqah Husna Abdul Rahim
No full textThis work presents an exploration of co-precipitated Zeolitic-Imidazolate Frameworks (ZIF) as direct use electrode materials for supercapacitors. The different ratios of metal salts and 2- methylimidazolate based linkers have been synthesized in 3: 10, 1:1 and 10:3 mmol, accordingly. In three-electrode system, Ni-ZIF-R3 and Co-ZIF-R3 with high metal content exhibit the highest specific capacitance of 433 F g-1 and 420 F g-1 at the current density of 0.25 A g-1 in 1 M KOH electrolyte, respectively. An asymmetrical supercapacitor (ASC) was fabricated using the configuration of Ni-ZIF- R3||KOH||AC and Co-ZIF-R3||KOH||AC. Within potential range of 1.70 V, both cells have delivered a high specific capacitance of 85 and 56 F g-1, respectively at current density of 0.25 A g-1. Moreover, Ni-ZIF-R3||KOH||AC revealed an excellence cycling stability of 93 % after 1500 cycles test. Similarly, Co-ZIF- R3||KOH||AC able to retain 87 % of its initial capacity after 2500 cycles at 0.50 A g-1 until 1.0 A g-1. Furthered, NiCo-ZIF with interconnected rod-shape like particles is studied as the comparison for the direct used-bimetallic with heated ZIFs. Surprisingly, the as-synthesized NiCo-ZIF delivered a better specific capacitance performance of 924 F g-1 at a current density of 0.50 A g-1. The optimization of all the samples are conducted in X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Field emission scanning electron microscopy (FESEM) and Energy dispersive X-Ray (EDX) to identify the role of molar ratio and the information of direct-used ZIF. Thus, this work highlighted the prospect of single and bimetallic based-ZIF prepared in co-precipitation with an appropriate parameter can be a potential electrode material for the next generation of high performance and stability of supercapacitors
Efficiency enhancement of photoelectrochemical water splitting by heterostructures Ag/MoS2/ZnO photoanode / Chia Mei Yuen
No full textCurrent work focuses on the preparation of Ag/MoS2/ZnO thin film as photoanode and evaluation of its efficiency for photoelectrochemical (PEC) water splitting. The sample is fabricated via facile wet-chemical synthesis method, where seedless hydrothermal growth of zinc oxide (ZnO) nanorods is conducted first followed by decoration of molybdenum disulfide (MoS2) flakes that integrated with silver (Ag) nanoparticles on ZnO nanorod’s surface via drop-coating method. The experimental design is based on cost saving concept without the need of excessive chemicals yet time-consuming seeding process and decoration/integration process. In each stage of samples preparation, the most optimum sample will be selected for to be used as matrix for following stage sample preparation. In first stage, ZnO nanorods were grown on indium doped tin oxide (ITO) via seeding process while that of aluminium doped zinc oxide (AZO) is without seeding process. It is found that although ZnO nanorods grown on ITO have smaller diameter but ZnO nanorods grown on AZO is more stable according to chronoamperometry measurement. In second stage, ZnO nanorods grown on AZO was chosen as matrix for MoS2 flakes decoration and the PEC results shows that ZnO nanorods that was decorated with three layers MoS2 flakes gives the highest photocurrent density. In last stage, Ag nanoparticles (with different weight percentage) were integrated onto MoS2 flakes to form Ag/MoS2 nanocomposite. Thereafter, this nanocomposite is integrated onto ZnO nanorods thin film for PEC application. The presence of Ag has renders plasmonic effect that can significantly reduce the recombination rate of electrons and holes in MoS2, where 20 wt% Ag/MoS2/ZnO gave the best PEC performance, 6 times higher in photoconversion efficiency and 8 times higher in hydrogen gas production is observed as-compared to the results of bare ZnO nanorods
Metaphoric and metonymic expressions of ‘Red’ in Song Poetry / Liu Yiting
No full textIn this study color terms about ‘red’ are selected from 300 Song Lyrics. Metonymy and metaphorical expression of this color term in 300 Song Lyrics would be classified, analyzed and discuss the cognitive mechanism behind these expressions. To find out what are the metonymic and metaphorical expressions of ‘red’ in ancient poetry (Song Lyrics). The study found four metonymic expressions that are commonly used in Song Lyrics, including (1) Red for spring, (2) Red for red flower, (3) Red for beautiful lady and (4) Red for red cosmetics, and four metaphoric expressions that are commonly used in Song Lyrics which are (1) Youth and vitality is red, (2) Power and wealth is red, (3) Mundane world is red, and (4) Prosperity is red. Besides, the method and mechanism by which figurative expressions of red terms are formed in the first place. By studying the color "red" in Song Lyrics, not only may native speakers become more aware of their cultural symbols, but non-native speakers and translators can gain a better understanding of the Chinese language and culture as well. Meanwhile, it is suggested that future researchers can be performing additional in-depth research on other color terms in order to further their understanding, and researchers are encouraged to look at the metaphor from both a synchronic and a diachronic perspective
An acoustic analysis of /Ɛ/ and /Ɔ/ in the Kelantan dialect / Raja Nurul Nadia Raja Abdul Razak
No full textThis study aims to describe the vowels /ɛ/ and /ɔ/ of Kelantan dialect (KD) with
acoustic analysis between two groups of speakers. The first group is born, raised, and
live in Kelantan (KDPP) while the second group is born and raised in Kelantan but
currently stay in Klang Valley (KDKL). This research uses an instrumental analysis
approach where an interview with the speakers is conducted in order to gather the data.
The collected data are measured and analysed using Praat developed by Boersma and
Weenink (2017). This research is to provide a quantitative analysis on two of the very
significant vowels in Kelantan dialect, /ɛ/ and /ɔ/. This study also intends to compare the
/ɛ/ and /ɔ/ vowels of KDPP and KDKL speakers, to see to what extent does the
difference of /ɛ/ and /ɔ/ vowel realisation between KDPP and KDKL speakers. It is
believed that it could provide a further understanding on KD and how the vowel quality
differs between the two groups. The findings reveal that the vowel /ɛ/ and /ɔ/ between
KDPP and KDKL speakers both male and female are realised differently and none of
them are conflated completely as one vowel. The production of /ɛ/ and /ɔ/ vowels
between KDPP and KDKL in this study is not entirely similar due to several reasons.
vowel /ɛ/ and /ɔ/ in this study both for KDPP and KDKL are not realised based on
sound patterns of the KD vowels
Thermal and economic analysis of a liquid flat plate solar collector system using green carbon nanofluids / Harish Kumar Loganathan
No full textThe present investigation deals with the effects of using cost-effective, eco-friendly, non-corrosive, covalent functionalized carbon-based nanofluids to evaluate the energetic, exergetic, and economic performance of a Liquid flat-plate solar collector (LFPSC) forced circulation system. Two types of green nanostructures namely, functionalized carbon nanostructures and hybrid carbon nanostructures were synthesized using the facile, eco-friendly, free radical technique. Different natural extracts such as gallic acid, parsley leaves, hibiscus leaves, and neem leaves are utilized in the preparation of green carbon nanofluids. The green nanofluids prepared are gallic acid graphene nanoplatelets (GGNPs), parsley graphene nanoplatelets (PGNPs), parsley multi-walled carbon nanotubes (PMWCNTs), GGNPs decorated with silver nanoparticles (GGNP-Ag), PGNPs decorated with copper oxide nanoparticles (PGNP-CuO), and PMWCNTs decorated with silver nanoparticles (PMWCNTS-Ag). The functionalization and decoration of carbon structures were confirmed using characterization techniques namely FESEM, EDX, TEM, XRD, FTIR, TGA. Green carbon nanofluids with base fluid distilled water were prepared with different weight concentrations of 0.025 %,0.05 % & 0.1 %. The green nanofluids prepared showed long-term colloidal stability compared to conventional nanofluids. Thermo-physical properties investigated showed increased thermal conductivity, viscosity, and density, while a decrease in specific heat capacity. For varying concentrations, fluid flow rates of 0.8,1.2, and 1.5 L/min, heat flux intensities of 600, 800, and 1000 W/m2, and inlet temperature ranging from 303 to 323 K were considered for the conduction of experiments. Improvement in energy and exergy efficiency was achieved using green carbon nanofluids than base fluid. Thermal efficiency surges with increment in flow rate and heat flux intensities, meanwhile it decreases for increment in inlet temperature. Maximum augmentation in thermal efficiency of about 30.2 % was achieved for PMWCNT nanofluid followed by 28.4 % for PMWCNT-Ag, 24.31 % for PGNP, 24 % for GGNP, 23.56 % for PGNP-CuO, and 22.24 % for GGNP-Ag at 0.1 wt. % and 1.5 L/min, respectively than the base fluid. Analysis of exergetic performance revealed that exergy efficiency reduces with a rise in mass flow rate meanwhile enhanced with an increase in nanofluid concentration. Exergy efficiency was maximum for 0.1% PMWCNT concentration and flow rate of 0.8 L/min. The maximum increase in friction factor values is approximately 11.61 % for 0.1 % PGNP-CuO nanofluids, followed by 10.9 %, 9.2 %,8 %,7.78 %,6.97 %, respectively for 0.1 % GGNP-Ag, PMWCNT-Ag, GGNP, PGNP and PMWCNT nanofluids than distilled water. Relative pumping power slightly increases with the increment of green carbon nanofluid concentration but is quite close to that of the base fluid. Performance index greater than one is obtained with higher values achieved at an increase in the weight concentration of green nanoparticles in the aqueous medium. Economic analysis showcased a maximum reduction of 28.89 % in the size of the collector area using 0.1 % PMWCNT nanofluid instead of distilled water. The average payback period for LFPSC using green carbon nanofluids was 6.40 % lesser than that of using distilled water. The enhanced properties of green carbon nanoparticles make them a favorable candidate in enhancing the performance of different thermal systems
Development of styrene-butyl acrylate-isoprene emulsion copolymer coating for natural rubber gloves / Chareeya I gi
No full textCoating natural rubber gloves with a layer of polymeric film is an essential process to improve donning properties of the gloves. In particular, polymeric coating with low coefficient of friction (CoF) is preferable for fast and easy donning. When coating an elastomeric article, there is an additional consideration where the coating layer can delaminate easily from the rubber substrate since the rubber article can be readily stretched. Hence, it is crucial to choose a right combination and composition of monomers to produce coating with a smooth surface and do not delaminate easily when stretched. In this research study, a newly developed styrene-butyl acrylate-isoprene (St-BA-Iso) emulsion copolymer was synthesized via seeded emulsion polymerization technique and the main objective of this study is to examine the effect of varying the composition of soft and hard monomers on the properties of emulsion and its coating performance in rubber gloves coating application. A series of St-BA-Iso emulsions of different monomers’ weight ratio were synthesized, and were subsequently formulated into polymeric coating solution to be coated on natural rubber film. The copolymers were characterized spectroscopically, as well as via microscopy, thermal and physical analyses. Carefully designed methodology and formulation has allowed the emulsions synthesis to achieve ≥ 90 % conversion, 41 ± 2 wt. % of total solid content, and desirable emulsions’ stability. In terms of coating performance on natural rubber film, copolymers comprised of higher loadings of soft monomers BA and Iso produced sticky films with a comparatively low glass transition temperature and higher CoF. Conversely, high loading of hard monomer St in the copolymer produced smooth coating surface with lower CoF but resulted in significant delamination from the rubber substrate when stretched due to high stiffness and poor coating adhesion. Of all synthesized copolymers, sample denoted as St-40 with 4 St: 3 BA: 3 Iso composition outperformed the rest as it was able to achieve a well-balanced donning properties, by demonstrating impressively smooth coating surface and at the same time retaining good coating adhesion on the rubber substrate. Hence, this makes St-40 an ideal copolymer emulsion for rubber glove coating applications