Displaying publications 1 - 20 of 1482 in total

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  1. Thye KL, Wan Abdullah WMAN, Balia Yusof ZN, Wee CY, Ong-Abdullah J, Loh JY, et al.
    Sci Rep, 2022 Nov 16;12(1):19639.
    PMID: 36385165 DOI: 10.1038/s41598-022-21909-7
    Banana (Musa acuminata) is an important fruit crop and source of income for various countries, including Malaysia. To date, current agrochemical practice has become a disputable issue due to its detrimental effect on the environment. λ-carrageenan, a natural polysaccharide extracted from edible red seaweed, has been claimed to be a potential plant growth stimulator. Hence, the present study investigates the effects of λ-carrageenan on plant growth using Musa acuminata cv. Berangan (AAA). Vegetative growth such as plant height, root length, pseudostem diameter, and fresh weight was improved significantly in λ-carrageenan-treated banana plants at an optimum concentration of 750 ppm. Enhancement of root structure was also observed in optimum λ-carrageenan treatment, facilitating nutrients uptake in banana plants. Further biochemical assays and gene expression analysis revealed that the increment in growth performance was consistent with the increase of chlorophyll content, protein content, and phenolic content, suggesting that λ-carrageenan increases photosynthesis rate, protein biosynthesis, and secondary metabolites biosynthesis which eventually stimulate growth. Besides, λ-carrageenan at optimum concentration also increased catalase and peroxidase activities, which led to a significant reduction in hydrogen peroxide and malondialdehyde, maintaining cellular homeostasis in banana plants. Altogether, λ-carrageenan at optimum concentration improves the growth of banana plants via inducing metabolic processes, enhancing nutrient uptake, and regulation of cell homeostasis. Further investigations are needed to evaluate the effectiveness of λ-carrageenan on banana plants under field conditions.
  2. Khamsanga S, Pornprasertsuk R, Yonezawa T, Mohamad AA, Kheawhom S
    Sci Rep, 2019 Jun 11;9(1):8441.
    PMID: 31186468 DOI: 10.1038/s41598-019-44915-8
    Manganese oxide (MnO2) is one of the most promising intercalation cathode materials for zinc ion batteries (ZIBs). Specifically, a layered type delta manganese dioxide (δ-MnO2) allows reversible insertion/extraction of Zn2+ ions and exhibits high storage capacity of Zn2+ ions. However, a poor conductivity of δ-MnO2, as well as other crystallographic forms, limits its potential applications. This study focuses on δ-MnO2 with nanoflower structure supported on graphite flake, namely MNG, for use as an intercalation host material of rechargeable aqueous ZIBs. Pristine δ-MnO2 nanoflowers and MNG were synthesized and examined using X-ray diffraction, electron spectroscopy, and electrochemical techniques. Also, performances of the batteries with the pristine δ-MnO2 nanoflowers and MNG cathodes were studied in CR2032 coin cells. MNG exhibits a fast insertion/extraction of Zn2+ ions with diffusion scheme and pseudocapacitive behavior. The battery using MNG cathode exhibited a high initial discharge capacity of 235 mAh/g at 200 mA/g specific current density compared to 130 mAh/g which is displayed by the pristine δ-MnO2 cathode at the same specific current density. MNG demonstrated superior electrical conductivity compared to the pristine δ-MnO2. The results obtained pave the way for improving the electrical conductivity of MnO2 by using graphite flake support. The graphite flake support significantly improved performances of ZIBs and made them attractive for use in a wide variety of energy applications.
  3. Khoshnam M, Farahbakhsh J, Zargar M, Mohammad AW, Benamor A, Ang WL, et al.
    Sci Rep, 2021 Oct 13;11(1):20378.
    PMID: 34645890 DOI: 10.1038/s41598-021-99849-x
    In this study, hematite graphene oxide (αFe2O3-GO) powder nanocomposites and thin-film hematite graphene oxide (αFe2O3-GO) were synthesized for application in the removal of Rhodamine B (RhB) from textile wastewater. αFe2O3-GO nanomaterials were placed onto the FTO substrate to form a thin layer of nanocomposites. Different analysis including XRD, FTIR, Raman spectra, XPS, and FESEM were done to analyze the morphology, structure, and properties of the synthesized composites as well as the chemical interactions of αFe2O3 with GO. The photocatalytic performance of two synthesized composites was compared with different concentrations of αFe2O3-GO. The results showed that powder nanocomposites are more effective than thin-film composites for the removal of RhB dye. αFe2O3-GO-5% powder nanocomposites removed over 64% of dye while thin-film nanocomposites had less removal efficiencies with just under 47% removal rate. The reusability test was done for both materials in which αFe2O3-GO-5% powder nanocomposites removed a higher rate of dye (up to 63%) in more cycles (6 cycles).
  4. Liu J, Lončar I, Collée JM, Bolla MK, Dennis J, Michailidou K, et al.
    Sci Rep, 2016 Nov 15;6:36874.
    PMID: 27845421 DOI: 10.1038/srep36874
    NBS1, also known as NBN, plays an important role in maintaining genomic stability. Interestingly, rs2735383 G > C, located in a microRNA binding site in the 3'-untranslated region (UTR) of NBS1, was shown to be associated with increased susceptibility to lung and colorectal cancer. However, the relation between rs2735383 and susceptibility to breast cancer is not yet clear. Therefore, we genotyped rs2735383 in 1,170 familial non-BRCA1/2 breast cancer cases and 1,077 controls using PCR-based restriction fragment length polymorphism (RFLP-PCR) analysis, but found no association between rs2735383CC and breast cancer risk (OR = 1.214, 95% CI = 0.936-1.574, P = 0.144). Because we could not exclude a small effect size due to a limited sample size, we further analyzed imputed rs2735383 genotypes (r2 > 0.999) of 47,640 breast cancer cases and 46,656 controls from the Breast Cancer Association Consortium (BCAC). However, rs2735383CC was not associated with overall breast cancer risk in European (OR = 1.014, 95% CI = 0.969-1.060, P = 0.556) nor in Asian women (OR = 0.998, 95% CI = 0.905-1.100, P = 0.961). Subgroup analyses by age, age at menarche, age at menopause, menopausal status, number of pregnancies, breast feeding, family history and receptor status also did not reveal a significant association. This study therefore does not support the involvement of the genotype at NBS1 rs2735383 in breast cancer susceptibility.
  5. Biabanikhankahdani R, Alitheen NBM, Ho KL, Tan WS
    Sci Rep, 2016 11 24;6:37891.
    PMID: 27883070 DOI: 10.1038/srep37891
    Multifunctional nanocarriers harbouring specific targeting moieties and with pH-responsive properties offer great potential for targeted cancer therapy. Several synthetic drug carriers have been studied extensively as drug delivery systems but not much information is available on the application of virus-like nanoparticles (VLNPs) as multifunctional nanocarriers. Here, we describe the development of pH-responsive VLNPs, based on truncated hepatitis B virus core antigen (tHBcAg), displaying folic acid (FA) for controlled drug delivery. FA was conjugated to a pentadecapeptide containing nanoglue bound on tHBcAg nanoparticles to increase the specificity and efficacy of the drug delivery system. The tHBcAg nanoparticles loaded with doxorubicin (DOX) and polyacrylic acid (PAA) demonstrated a sustained drug release profile in vitro under tumour tissue conditions in a controlled manner and improved the uptake of DOX in colorectal cancer cells, leading to enhanced antitumour effects. This study demonstrated that DOX-PAA can be packaged into VLNPs without any modification of the DOX molecules, preserving the pharmacological activity of the loaded DOX. The nanoglue can easily be used to display a tumour-targeting molecule on the exterior surface of VLNPs and can bypass the laborious and time-consuming genetic engineering approaches.
  6. Gao Y, Zhang W, Liu C, Li G
    Sci Rep, 2019 12 11;9(1):18844.
    PMID: 31827114 DOI: 10.1038/s41598-019-54289-6
    Resistance to tamoxifen is a major clinical challenge. Research in recent years has identified epigenetic changes as mediated by dysregulated miRNAs that can possibly play a role in resistance to tamoxifen in breast cancer patients expressing estrogen receptor (ER). We report here elevated levels of EMT markers (vimentin and ZEB1/2) and reduced levels of EMT-regulating miR-200 (miR-200b and miR-200c) in ER-positive breast cancer cells, MCF-7, that were resistant to tamoxifen, in contrast with the naïve parental MCF-7 cells that were sensitive to tamoxifen. Further, we established regulation of c-MYB by miR-200 in our experimental model. C-MYB was up-regulated in tamoxifen resistant cells and its silencing significantly decreased resistance to tamoxifen and the EMT markers. Forced over-expression of miR-200b/c reduced c-MYB whereas reduced expression of miR-200b/c resulted in increased c-MYB We further confirmed the results in other ER-positive breast cancer cells T47D cells where forced over-expression of c-MYB resulted in induction of EMT and significantly increased resistance to tamoxifen. Thus, we identify a novel mechanism of tamoxifen resistance in breast tumor microenvironment that involves miR-200-MYB signaling.
  7. Chong JS, Chan YL, Ebenezer EGM, Chen HY, Kiguchi M, Lu CK, et al.
    Sci Rep, 2020 12 16;10(1):22041.
    PMID: 33328535 DOI: 10.1038/s41598-020-79053-z
    This study aims to investigate the generalizability of the semi-metric analysis of the functional connectivity (FC) for functional near-infrared spectroscopy (fNIRS) by applying it to detect the dichotomy in differential FC under affective and neutral emotional states in nursing students and registered nurses during decision making. The proposed method employs wavelet transform coherence to construct FC networks and explores semi-metric analysis to extract network redundancy features, which has not been considered in conventional fNIRS-based FC analyses. The trials of the proposed method were performed on 19 nursing students and 19 registered nurses via a decision-making task under different emotional states induced by affective and neutral emotional stimuli. The cognitive activities were recorded using fNIRS, and the emotional stimuli were adopted from the International Affective Digitized Sound System (IADS). The induction of emotional effects was validated by heart rate variability (HRV) analysis. The experimental results by the proposed method showed significant difference (FDR-adjusted p = 0.004) in the nursing students' cognitive FC network under the two different emotional conditions, and the semi-metric percentage (SMP) of the right prefrontal cortex (PFC) was found to be significantly higher than the left PFC (FDR-adjusted p = 0.036). The benchmark method (a typical weighted graph theory analysis) gave no significant results. In essence, the results support that the semi-metric analysis can be generalized and extended to fNIRS-based functional connectivity estimation.
  8. Mousavi Z, Soofivand F, Esmaeili-Zare M, Salavati-Niasari M, Bagheri S
    Sci Rep, 2016 Feb 01;6:20071.
    PMID: 26832329 DOI: 10.1038/srep20071
    In this work, zinc chromite (ZnCr2O4) nanostructures have been synthesized through co-precipitation method. The effect of various parameters such as alkaline agent, pH value, and capping agent type was investigated on purity, particle size and morphology of samples. It was found that particle size and morphology of the products could be greatly influenced via these parameters. The synthesized products were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), fourier transform infrared (FT-IR) spectra, X-ray energy dispersive spectroscopy (EDS), photoluminescence (PL) spectroscopy, diffuse reflectance spectroscopy (DRS) and vibrating sample magnetometry (VSM). The superhydrophilicity of the calcined oxides was investigated by wetting experiments and a sessile drop technique which carried out at room temperature in air to determine the surface and interfacial interactions. Furthermore, the photocatalytic activity of ZnCr2O4 nanoparticles was confirmed by degradation of anionic dyes such as Eosin-Y and phenol red under UV light irradiation. The obtained ZnCr2O4 nanoparticles exhibit a paramagnetic behavior although bulk ZnCr2O4 is antiferromagnetic, this change in magnetic property can be ascribed to finite size effects.
  9. Ng TYS, Chew TL, Yeong YF, Jawad ZA, Ho CD
    Sci Rep, 2019 10 21;9(1):15062.
    PMID: 31636339 DOI: 10.1038/s41598-019-51460-x
    In recent years, there are increasing interest on applying ultrasonic irradiation for the synthesis of zeolite due to its advantages including remarkable shortened synthesis duration. In this project, the potential of ultrasonic irradiation treatment on the synthesis of zeolite RHO was investigated. Ultrasonic irradiation treatment time was varied from 30 to 120 minutes for the synthesis of zeolite RHO. The zeolite RHO solid samples were characterized with X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA) and nitrogen adsorption-desorption analysis. The application of ultrasonic irradiation treatment in this study has accelerated the synthesis of zeolite RHO where the synthesis duration has been significantly shortened to 2 days compared to 8 days required by conventional hydrothermal heating without ultrasonic irradiation treatment. Highly crystalline zeolite RHO crystals in truncated octahedron morphology were successfully formed.
  10. Rahimi M, Ng EP, Bakhtiari K, Vinciguerra M, Ali Ahmad H, Awala H, et al.
    Sci Rep, 2015 Nov 30;5:17259.
    PMID: 26616161 DOI: 10.1038/srep17259
    The affinity of zeolite nanoparticles (diameter of 8-12 nm) possessing high surface area and high pore volume towards human plasma proteins has been investigated. The protein composition (corona) of zeolite nanoparticles has been shown to be more dependent on the plasma protein concentrations and the type of zeolites than zeolite nanoparticles concentration. The number of proteins present in the corona of zeolite nanoparticles at 100% plasma (in vivo state) is less than with 10% plasma exposure. This could be due to a competition between the proteins to occupy the corona of the zeolite nanoparticles. Moreover, a high selective adsorption for apolipoprotein C-III (APOC-III) and fibrinogen on the zeolite nanoparticles at high plasma concentration (100%) was observed. While the zeolite nanoparticles exposed to low plasma concentration (10%) exhibited a high selective adsorption for immunoglobulin gamma (i.e. IGHG1, IGHG2 and IGHG4) proteins. The zeolite nanoparticles can potentially be used for selectively capture of APOC-III in order to reduce the activation of lipoprotein lipase inhibition during hypertriglyceridemia treatment. The zeolite nanoparticles can be adapted to hemophilic patients (hemophilia A (F-VIII deficient) and hemophilia B (F-IX deficient)) with a risk of bleeding, and thus might be potentially used in combination with the existing therapy.
  11. Chen YM, Chen LH, Li MP, Li HF, Higuchi A, Kumar SS, et al.
    Sci Rep, 2017 03 23;7:45146.
    PMID: 28332572 DOI: 10.1038/srep45146
    Establishing cultures of human embryonic (ES) and induced pluripotent (iPS) stem cells in xeno-free conditions is essential for producing clinical-grade cells. Development of cell culture biomaterials for human ES and iPS cells is critical for this purpose. We designed several structures of oligopeptide-grafted poly (vinyl alcohol-co-itaconic acid) hydrogels with optimal elasticity, and prepared them in formations of single chain, single chain with joint segment, dual chain with joint segment, and branched-type chain. Oligopeptide sequences were selected from integrin- and glycosaminoglycan-binding domains of the extracellular matrix. The hydrogels grafted with vitronectin-derived oligopeptides having a joint segment or a dual chain, which has a storage modulus of 25 kPa, supported the long-term culture of human ES and iPS cells for over 10 passages. The dual chain and/or joint segment with cell adhesion molecules on the hydrogels facilitated the proliferation and pluripotency of human ES and iPS cells.
  12. Batumalaie K, Amin MA, Murugan DD, Sattar MZ, Abdullah NA
    Sci Rep, 2016 06 02;6:27236.
    PMID: 27250532 DOI: 10.1038/srep27236
    Activation of inflammatory pathways via reactive oxygen species (ROS) by free fatty acids (FFA) in obesity gives rise to insulin resistance and endothelial dysfunction. Withaferin A (WA), possesses both antioxidant and anti-inflammatory properties and therefore would be a good strategy to suppress palmitic acid (PA)-induced oxidative stress and inflammation and hence, insulin resistance and dysfunction in the endothelium. Effect of WA on PA-induced insulin resistance in human umbilical vein endothelial cells (HUVECs) was determined by evaluating insulin signaling mechanisms whilst effect of this drug on PA-induced endothelial dysfunction was determined in acetylcholine-mediated relaxation in isolated rat aortic preparations. WA significantly inhibited ROS production and inflammation induced by PA. Furthermore, WA significantly decreased TNF-α and IL-6 production in endothelial cells by specifically suppressing IKKβ/NF-κβ phosphorylation. WA inhibited inflammation-stimulated IRS-1 serine phosphorylation and improved the impaired insulin PI3-K signaling, and restored the decreased nitric oxide (NO) production triggered by PA. WA also decreased endothelin-1 and plasminogen activator inhibitor type-1 levels, and restored the impaired endothelium-mediated vasodilation in isolated aortic preparations. These findings suggest that WA inhibited both ROS production and inflammation to restore impaired insulin resistance in cultured endothelial cells and improve endothelial dysfunction in rat aortic rings.
  13. Che Hamzah AM, Chew CH, Al-Trad EI, Puah SM, Chua KH, A Rahman NI, et al.
    Sci Rep, 2024 Feb 12;14(1):3485.
    PMID: 38347106 DOI: 10.1038/s41598-024-54182-x
    Despite the importance of methicillin-resistant Staphylococcus aureus (MRSA) as a priority nosocomial pathogen, the genome sequences of Malaysian MRSA isolates are currently limited to a small pool of samples. Here, we present the genome sequence analyses of 88 clinical MRSA isolates obtained from the main tertiary hospital in Terengganu, Malaysia in 2016-2020, to obtain in-depth insights into their characteristics. The EMRSA-15 (ST22-SCCmec IV) clone of the clonal complex 22 (CC22) lineage was predominant with a total of 61 (69.3%) isolates. Earlier reports from other Malaysian hospitals indicated the predominance of the ST239 clone, but only two (2.3%) isolates were identified in this study. Two Indian-origin clones, the Bengal Bay clone ST772-SCCmec V (n = 2) and ST672 (n = 10) were also detected, with most of the ST672 isolates obtained in 2020 (n = 7). Two new STs were found, with one isolate each, and were designated ST7879 and ST7883. From the core genome phylogenetic tree, the HSNZ MRSA isolates could be grouped into seven clades. Antimicrobial phenotype-genotype concordance was high (> 95%), indicating the accuracy of WGS in predicting most resistances. Majority of the MRSA isolates were found to harbor more than 10 virulence genes, demonstrating their pathogenic nature.
  14. Benavente ED, Gomes AR, De Silva JR, Grigg M, Walker H, Barber BE, et al.
    Sci Rep, 2019 07 08;9(1):9873.
    PMID: 31285495 DOI: 10.1038/s41598-019-46398-z
    The zoonotic Plasmodium knowlesi parasite is the most common cause of human malaria in Malaysia. Genetic analysis has shown that the parasites are divided into three subpopulations according to their geographic origin (Peninsular or Borneo) and, in Borneo, their macaque host (Macaca fascicularis or M. nemestrina). Whilst evidence suggests that genetic exchange events have occurred between the two Borneo subpopulations, the picture is unclear in less studied Peninsular strains. One difficulty is that P. knowlesi infected individuals tend to present with low parasitaemia leading to samples with insufficient DNA for whole genome sequencing. Here, using a parasite selective whole genome amplification approach on unprocessed blood samples, we were able to analyse recent genomes sourced from both Peninsular Malaysia and Borneo. The analysis provides evidence that recombination events are present in the Peninsular Malaysia parasite subpopulation, which have acquired fragments of the M. nemestrina associated subpopulation genotype, including the DBPβ and NBPXa erythrocyte invasion genes. The NBPXb invasion gene has also been exchanged within the macaque host-associated subpopulations of Malaysian Borneo. Our work provides strong evidence that exchange events are far more ubiquitous than expected and should be taken into consideration when studying the highly complex P. knowlesi population structure.
  15. Muhamad Sarih N, Myers P, Slater A, Slater B, Abdullah Z, Tajuddin HA, et al.
    Sci Rep, 2019 08 14;9(1):11834.
    PMID: 31413269 DOI: 10.1038/s41598-019-47847-5
    Three fluorescent organic compounds-furocoumarin (FC), dansyl aniline (DA), and 7-hydroxycoumarin-3-carboxylic acid (CC)-are mixed to produce almost pure white light emission (WLE). This novel mixture is immobilised in silica aerogel and applied as a coating to a UV LED to demonstrate its applicability as a low-cost, organic coating for WLE via simultaneous emission. In ethanol solution and when immobilised in silica aerogel, the mixture exhibits a Commission Internationale d'Eclairage (CIE) chromaticity index of (0.27, 0.33). It was observed that a broadband and simultaneous emission involving coumarin carboxylic acid, furocoumarin and dansyl aniline played a vital role in obtaining a CIE index close to that of pure white light.
  16. Sunardi S, Ariyani M, Agustian M, Withaningsih S, Parikesit P, Juahir H, et al.
    Sci Rep, 2020 07 06;10(1):11110.
    PMID: 32632183 DOI: 10.1038/s41598-020-68026-x
    Reservoirs play a strategic role in the context of sustainable energy supply. Unfortunately, the majority of the reservoirs are facing water-quality degradation due to complex pollutants originating from activities both in the catchment and inside the reservoir. This research was aimed at assessing the extent of the water degradation, in terms of corrosivity level, and at examining its impacts on hydropower capacity and operation. Water quality data (total dissolved solids, pH, calcium, bicarbonate, and temperature) were obtained from 20 sampling stations in the Cirata Reservoir from 2007 to 2016. The results show that the river water is already corrosive (Langelier Saturation Index, LSI = - 0.21 to - 1.08), and, the corrosiveness becoming greater when entering the reservoir (LSI = - 0.52 to - 1.49). The water corrosivity has caused damage to the hydro-mechanical equipment and lowering production capacity. The external environment of the catchment hosts complex human activities, such as agriculture, land conversion, urban and industrial discharge, which have all played a major role in the water corrosiveness. Meanwhile, the internal environment, such as floating net cage aquaculture, has intensified the problem. As the water corrosiveness has increased, the maintenance of the hydro-mechanical facilities has also increased. Strategies must be applied as current conditions are certainly a threat to the sustainability of the hydropower operation and, hence, the energy supply.
  17. Bin Rafiq MKS, Amin N, Alharbi HF, Luqman M, Ayob A, Alharthi YS, et al.
    Sci Rep, 2020 Jan 21;10(1):771.
    PMID: 31964954 DOI: 10.1038/s41598-020-57596-5
    Radio frequency (RF) magnetron sputtering was used to deposit tungsten disulfide (WS2) thin films on top of soda lime glass substrates. The deposition power of RF magnetron sputtering varied at 50, 100, 150, 200, and 250 W to investigate the impact on film characteristics and determine the optimized conditions for suitable application in thin-film solar cells. Morphological, structural, and opto-electronic properties of as-grown films were investigated and analyzed for different deposition powers. All the WS2 films exhibited granular morphology and consisted of a rhombohedral phase with a strong preferential orientation toward the (101) crystal plane. Polycrystalline ultra-thin WS2 films with bandgap of 2.2 eV, carrier concentration of 1.01 × 1019 cm-3, and resistivity of 0.135 Ω-cm were successfully achieved at RF deposition power of 200 W. The optimized WS2 thin film was successfully incorporated as a window layer for the first time in CdTe/WS2 solar cell. Initial investigations revealed that the newly incorporated WS2 window layer in CdTe solar cell demonstrated photovoltaic conversion efficiency of 1.2% with Voc of 379 mV, Jsc of 11.5 mA/cm2, and FF of 27.1%. This study paves the way for WS2 thin film as a potential window layer to be used in thin-film solar cells.
  18. Abdullah MK, Hassan LH, Moghavvemi M
    Sci Rep, 2022 Dec 24;12(1):22279.
    PMID: 36566331 DOI: 10.1038/s41598-022-26751-5
    Three static techniques (i.e. Power flow, Continuation Power Flow (CPF) and the Q-V curve) are used to assess the voltage stability of the power grid with a Solar Photovoltaic Generator (SPVG) and FACTS devices under nominal and heavy loading conditions. A static model is proposed for the power system that includes conventional power generation units and SPVGs with FACTS devices. Two models of SPVG were used (i.e., PV-model and PQ-model) to elucidate the effect of the SPVGs on the stability of the voltage under various operating conditions. The best location for FACTS devices was obtained under nominal and heavy load conditions using static techniques. A comparison between series and shunt FACTS devices under nominal and heavy loading conditions was carried out using the three static techniques. The interaction between SPVGs and FACTS devices was detailed in this paper. The proposed approach was tested on the New England 39-bus standard test system, and the results confirmed the effectiveness of the proposed approach under various operating conditions.
  19. Rosmi MS, Yusop MZ, Kalita G, Yaakob Y, Takahashi C, Tanemura M
    Sci Rep, 2014;4:7563.
    PMID: 25523645 DOI: 10.1038/srep07563
    Control synthesis of high quality large-area graphene on transition metals (TMs) by chemical vapor deposition (CVD) is the most fascinating approach for practical device applications. Interaction of carbon atoms and TMs is quite critical to obtain graphene with precise layer number, crystal size and structure. Here, we reveal a solid phase reaction process to achieve Cu assisted graphene growth in nanoscale by in-situ transmission electron microscope (TEM). Significant structural transformation of amorphous carbon nanofiber (CNF) coated with Cu is observed with an applied potential in a two probe system. The coated Cu particle recrystallize and agglomerate toward the cathode with applied potential due to joule heating and large thermal gradient. Consequently, the amorphous carbon start crystallizing and forming sp(2) hybridized carbon to form graphene sheet from the tip of Cu surface. We observed structural deformation and breaking of the graphene nanoribbon with a higher applied potential, attributing to saturated current flow and induced Joule heating. The observed graphene formation in nanoscale by the in-situ TEM process can be significant to understand carbon atoms and Cu interaction.
  20. Pai YS, Yap HJ, Md Dawal SZ, Ramesh S, Phoon SY
    Sci Rep, 2016 06 07;6:27380.
    PMID: 27271840 DOI: 10.1038/srep27380
    This study presents a modular-based implementation of augmented reality to provide an immersive experience in learning or teaching the planning phase, control system, and machining parameters of a fully automated work cell. The architecture of the system consists of three code modules that can operate independently or combined to create a complete system that is able to guide engineers from the layout planning phase to the prototyping of the final product. The layout planning module determines the best possible arrangement in a layout for the placement of various machines, in this case a conveyor belt for transportation, a robot arm for pick-and-place operations, and a computer numerical control milling machine to generate the final prototype. The robotic arm module simulates the pick-and-place operation offline from the conveyor belt to a computer numerical control (CNC) machine utilising collision detection and inverse kinematics. Finally, the CNC module performs virtual machining based on the Uniform Space Decomposition method and axis aligned bounding box collision detection. The conducted case study revealed that given the situation, a semi-circle shaped arrangement is desirable, whereas the pick-and-place system and the final generated G-code produced the highest deviation of 3.83 mm and 5.8 mm respectively.
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