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  • MDPI AG  (179)
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  • MDPI AG  (179)
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  • 1
    In: Crystals, MDPI AG, Vol. 12, No. 11 ( 2022-10-27), p. 1526-
    Abstract: Objective: To fabricate a lightweight, breathable, comfortable, and able to contour to the curvilinear body shape, electrodes built on a flexible substrate are a significant growth in wearable health monitoring. This research aims to create a GNP/FE electrode-based EEG signal acquisition system that is both efficient and inexpensive. Methodology: Three distinct electrode concentrations were developed for EEG signal acquisition, three distinct electrode concentrations (1.5:1.5, 2:1, and 3:0). The high strength-to-weight ratio to form the tribofilm in the fabrication of the electrode will provide good efficiency. The EEG signal is first subjected to a wavelet transform, which serves as a preliminary analysis. The use of biopotential signals in wearable systems as biofeedback or control commands is expected to substantially impact point-of-care health monitoring systems, rehabilitation devices, human–computer/machine interfaces (HCI/HMI), and brain–computer interfaces (BCIs). The graphene oxide (GO), glycerol (GL), and polyvinyl alcohol (PVA) GO/GL/PVA plastic electrodes were measured and compared to that of a commercially available electrode using the biopic equipment. The GO/GL/PVA plastic electrode was able to detect EEG signals satisfactorily after being used for two months, demonstrating good conductivity and lower noise than the commercial electrode. The GO/GL/PVA nanocomposite mixture was put into the electrode mold as soon as it was ready and then rapidly chilled. Results: The quality of an acquired EEG signal could be measured in several ways including by its error percentage, correlation coefficient, and signal-to-noise ratio (SNR). The fabricated electrode yield detection ranged from 0.81 kPa−1 % to 34.90 kPa−1%. The performance was estimated up to the response of 54 ms. Linear heating at the rate of 40 °C per minute was implemented on the sample ranges from 0 °C to 240 °C. During the sample electrode testing in EEG signal analysis, it obtained low impedance with a good quality of signal acquisition when compared to a conventional wet type of electrode. Conclusions: A large database was frequently built from all of the simulated signals in MATLAB code. Through the experiment, all of the required data were collected, checked against all other signals, and proven that they were accurate representations of the intended database. Evidence suggests that graphene nanoplatelets (GNP) hematite (FE2O3) polyvinylidene fluoride (PVDF) GNP/FE2O3@PVDF electrodes with a 3:0 concentration yielded the best outcomes.
    Type of Medium: Online Resource
    ISSN: 2073-4352
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2661516-2
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  • 2
    In: Genes, MDPI AG, Vol. 12, No. 9 ( 2021-09-20), p. 1448-
    Abstract: Background: This study aimed to identify new genes associated with CRC in patients with normal mismatch repair (MMR) protein expression. Method: Whole-genome sequencing (WGS) was performed in seven early-age-onset Malay CRC patients. Potential germline genetic variants, including single-nucleotide variations and insertions and deletions (indels), were prioritized using functional and predictive algorithms. Results: An average of 3.2 million single-nucleotide variations (SNVs) and over 800 indels were identified. Three potential candidate variants in three genes—IFNE, PTCH2 and SEMA3D—which were predicted to affect protein function, were identified in three Malay CRC patients. In addition, 19 candidate genes—ANKDD1B, CENPM, CLDN5, MAGEB16, MAP3K14, MOB3C, MS4A12, MUC19, OR2L8, OR51Q1, OR51AR1, PDE4DIP, PKD1L3, PRIM2, PRM3, SEC22B, TPTE, USP29 and ZNF117—harbouring nonsense variants were prioritised. These genes are suggested to play a role in cancer predisposition and to be associated with cancer risk. Pathway enrichment analysis indicated significant enrichment in the olfactory signalling pathway. Conclusion: This study provides a new spectrum of insights into the potential genes, variants and pathways associated with CRC in Malay patients.
    Type of Medium: Online Resource
    ISSN: 2073-4425
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2527218-4
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  • 3
    In: Electronics, MDPI AG, Vol. 12, No. 12 ( 2023-06-20), p. 2754-
    Abstract: This study proposed the dimensions of 55 mm × 34 mm × 1 mm for wearable antenna; the copper Y-slot patch and copper partial ground are attached to a felt substrate. The partial ground has the higher impact in antenna gain enhancement compared with the full ground, making it the most suitable candidate for wearable applications and suitable for embedding in fabrics for use in medical applications. In addition, the proposed antenna design combined a fabric–metal barrier operated at 2.4 GHz 65.4% with a low specific absorption rate (SAR) of 0.01 watts per kilogramme (W/kg) and 0.006 W/kg per 10 g and a gain of 6.48 dBi. The proposed antenna has an omnidirectional radiation pattern. The two-layer barrier is designed to achieve high electromagnetic (EM) absorption and reduce the antenna’s absorption coefficient (SAR) for safe use in applications involving human activities. Simulation and measurement results on the arm and the head of the human body indicated that the antenna has excellent performance. In addition, the measurement results agreed well with the simulation results, making the proposed wearable antenna reliable for medical and 5G applications.
    Type of Medium: Online Resource
    ISSN: 2079-9292
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2662127-7
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  • 4
    Online Resource
    Online Resource
    MDPI AG ; 2020
    In:  Energies Vol. 13, No. 17 ( 2020-09-01), p. 4532-
    In: Energies, MDPI AG, Vol. 13, No. 17 ( 2020-09-01), p. 4532-
    Abstract: Electrification of road transport is a major step to solve the air quality problem and general environmental impact caused by the still widespread use of fossil fuels. At the same time, energy efficiency in the transport sector must be improved as a steppingstone towards a more sustainable future. Multiple waste heat recovery technologies are being investigated for low-temperature waste heat recovery. One of the technologies that is being considered for vehicle application is the Organic Rankine Cycle (ORC). In this paper, the potential of ORC is discussed in detail for hybrid vehicle application. The modelling and testing of multiple systems such as the hybrid vehicle, engine, and ORC waste heat recovery are performed using the computational approach in GT-SUITE software environment correlated against available engine data. It was found that the maximum cycle efficiency achieved from the ORC system was 5.4% with 2.02 kW of delivered power recovered from the waste heat available. This led to 1.0% and 1.2% of fuel economy improvement in the New European Driving Cycle (NEDC) and Worldwide Harmonised Light Vehicle Test Procedure (WLTP) driving cycle test, respectively. From the driving cycle analysis, Hybrid Electric Vehicles (HEV) and ORC are operative in a different part of the driving cycle. This is because the entire propulsion power is provided by the HEV system, resulting in less engine operation in some part of the cycle for the ORC system to function. Apart from that, a brief economic analysis of ORC Waste Heat Recovery (WHR) is also performed in this paper and a comparative analysis is carried out for different waste heat recovery technologies for hybrid vehicle application.
    Type of Medium: Online Resource
    ISSN: 1996-1073
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2437446-5
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  • 5
    Online Resource
    Online Resource
    MDPI AG ; 2021
    In:  International Journal of Environmental Research and Public Health Vol. 18, No. 7 ( 2021-04-06), p. 3831-
    In: International Journal of Environmental Research and Public Health, MDPI AG, Vol. 18, No. 7 ( 2021-04-06), p. 3831-
    Abstract: Happiness is an essential component to experience healthy ageing. Hence, understanding the factors that contribute to happiness is important. This study aimed to determine the factors associated with happiness among the elderly population in Malaysia. In this study, 1204 respondents were recruited from urban and rural areas in Selangor. A face-to-face interview was conducted using the Bahasa Malaysia version of the Japan Gerontological Evaluation Study questionnaire. The inclusion criteria include Malaysians who are 60-years old and above and can converse in the Malaysian language. Those who encounter less than seven scores for the Abbreviated Mental Test were excluded from the study. Among the 1204 respondents, 953 (79.2%) were happy. Sociodemographic characteristics showed that being a men, age of 60 to 74 years, and living in urban areas were significantly associated with happiness. A logistic regression model showed that locality (aOR 1.61), income category (Bottom 40% aOR 0.49; Middle-class group 40% aOR 1.40), social engagement (active aOR 1.77; less active aOR 1.25), receiving emotional support (aOR 2.11) and handgrip strength (aOR 1.02) were significantly associated with happiness. Thus, ensuring the elderly population in receiving emotional support and active social engagement among them can enhance their happiness level.
    Type of Medium: Online Resource
    ISSN: 1660-4601
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2175195-X
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  • 6
    In: Children, MDPI AG, Vol. 7, No. 8 ( 2020-08-18), p. 101-
    Abstract: (1) Purpose: To assess the oral health literacy (OHL) of parents and its association with the caries experience of their preschool children attending the Hospital University Sains Malaysia (HUSM), Kota Bharu, Kelantan, Malaysia. (2) Materials and Methods: This is a descriptive cross-sectional study involving a systematic random sampling method, using a sample of 230 parent/preschool child dyads. Among 230 parents, 24 were males and 206 were females (mean age 31.43 ± 5.82); among 230 children, 92 were boys and 138 were girls (mean age 4.82 ± 1.04) attending the pedodontics clinic, HUSM, who participated and met the inclusion criteria. A structured, self-administered oral health literacy questionnaire including sociodemographic factors was used in this study. A child’s oral examination was performed to check the dmft (decayed, missing, filled teeth) status. Statistical analysis was done using descriptive and Spearman’s correlation analysis and multivariate regression analysis. (3) Results: The mean dmft score of children in relation to the OHL level of parents showed a significant difference (p 〈 0.00). The mean dmft score of children in relation to the OHL level of parents showed the following relationships: Inadequate (7.49 ± 4.10) followed by marginal (3.28 ± 2.67) and then adequate (0.55 ± 1.55). The incidence of caries amongst children in relation to parental employment was more associated with unemployed parents (6.11 ± 4.43) than with employed parents (2.79 ± 3.65). The caries experience amongst children in relation to education of their parents revealed a significant difference (p 〈 0.001), and the mean dmft score was high amongst preschool children with primary school qualified parents (10.7 ± 4.10) followed by high school (7.04 ± 3.68), vocational (5.81 ± 3.57), diploma (2.61 ± 2.81), and university (1.29 ± 2.27), respectively. The results revealed a valid significant difference (negative correlation, rs = −0.753 **) between the OHL of parents with the dmft score of their preschool children. The age and gender of parents was not significantly associated with OHL, whereas ethnicity (positive correlation, rs = 0.283 **), education (positive correlation, rs = 0.865 **), and employment (negative correlation, rs = −0.490 **) were found to be significant. Conclusion: We conclude that there is a significant association between the OHL of parents with the dmft score of their preschool children. The logistic regression showed that after adjustment for sociodemographic factors, parents’ gender (OR = 0.067, 95% CI: 0.012–0.360), parents’ employment status (OR = 3.247, 95% CI: 0.897–11.754), parents’ OHL score (OR = 0.042, 95% CI: 0.016–0.114), and child age (OR = 2.195, 95% CI: 1.249–3.857) were significantly associated with dental caries in children. Our study concluded that parents’ employment status, age, gender, OHL, and child’s age were significantly associated with the caries experience of their preschool children.
    Type of Medium: Online Resource
    ISSN: 2227-9067
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2732685-8
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  • 7
    In: Crystals, MDPI AG, Vol. 10, No. 7 ( 2020-07-16), p. 621-
    Abstract: Fabricating GaN-based light-emitting diodes (LEDs) on a silicon (Si) substrate, which is compatible with the widely employed complementary metal–oxide–semiconductor (CMOS) circuits, is extremely important for next-generation high-performance electroluminescence devices. We conducted a systematic investigation of the optical properties of vertical LEDs, to reveal the impacts of the manufacturing process on their optical characteristics. Here, we fabricated and characterized high-efficiency GaN-based LEDs with integrated surface textures including micro-scale periodic hemispherical dimples and nano-scale random hexagonal pyramids on a 4 inch p-type Si substrate. The highly reflective Ag/TiW metallization scheme was performed to decrease downward-absorbing light. We demonstrated the influence of transferring LED epilayers from a sapphire substrate onto the Si substrate on the emission characteristics of the vertical LEDs. The removal of the sapphire substrate reduced the adverse impacts of the quantum-confined Stark effect (QCSE). The influence of integrated surface textures on the light extraction efficiency (LEE) of the vertical LEDs was studied. With the injection current of 350 mA, vertical LEDs with integrated surface textures demonstrated an excellent light output power of 468.9 mW with an emission peak wavelength of 456 nm. This work contributes to the integration of GaN-based vertical LEDs into Si-based integrated circuits.
    Type of Medium: Online Resource
    ISSN: 2073-4352
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2661516-2
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  • 8
    In: Applied Sciences, MDPI AG, Vol. 11, No. 3 ( 2021-01-25), p. 1053-
    Abstract: Since antennas are strong radar targets, their radar cross section (RCS) reduction and radiation enhancement is of utmost necessity, particularly for stealth platforms. This work proposes the design of a Fabry–Perot Cavity (FPC) antenna which has wideband low monostatic RCS. While in the transmission mode, not only is gain enhancement achieved, but radiation beam is also deflected in the elevation plane. Moreover, the design is low-profile, i.e., the cavity height is ~λ/4. A patch antenna designed at 6 GHz serves as the excitation source of the cavity constructed between the metallic ground plane and superstrate. The superstrate structure is formed with absorptive frequency selective surface (AFSS) in conjunction with dual-sided partially reflective surface (PRS). Resistor loaded metallic rings serve as the AFSS, while PRS is constructed from inductive gradated mesh structure on one side to realize phase gradient for beam deflection; the other side has fixed capacitive elements. Results show that wideband RCS reduction was achieved from 4–16 GHz, with average RCS reduction of about 8.5 dB over the reference patch antenna. Off-broadside peak radiation at −38° was achieved, with gain approaching ~9.4 dB. Simulation and measurement results are presented.
    Type of Medium: Online Resource
    ISSN: 2076-3417
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2704225-X
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  • 9
    In: Electronics, MDPI AG, Vol. 10, No. 3 ( 2021-01-23), p. 267-
    Abstract: Communication with low radar signature platforms requires antennas with low backscatter, to uphold the low observability attribute of the platforms. In this work, we present the design for a Fabry–Perot (F-P) cavity antenna with low monostatic radar cross section (RCS) and enhanced gain. In addition, peak radiation is tilted inthe elevation plane. This is achieved by incorporating phase gradient metasurface (PGM) with absorptive frequency selective surface (FSS). The periodic surface of metallic square loops with lumped resistors forms the absorptive surface, placed on top of a partially reflecting surface (PRS) with an intervening air gap. The double-sided PRS consists of uniform metallic patches etched in a periodic fashion on its upper side. The bottom surface consists of variable-sized metallic patches, to realize phase gradient. The superstrate assembly is placed at about half free space wavelength above the patch antenna resonating at 6.6 GHz. The antenna’s ground plane and PRS together construct the F-P cavity. A peak gain of 11.5 dBi is achieved at 13° tilt of the elevation plane. Wideband RCS reduction is achieved, spanning 5.6–16 GHz, for x- and y-polarizations of normally incident plane wave. The average RCS reduction is 13 dB. Simulation results with experimental verifications are presented.
    Type of Medium: Online Resource
    ISSN: 2079-9292
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2662127-7
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  • 10
    In: Molecules, MDPI AG, Vol. 17, No. 2 ( 2012-02-16), p. 1969-1991
    Type of Medium: Online Resource
    ISSN: 1420-3049
    Language: English
    Publisher: MDPI AG
    Publication Date: 2012
    detail.hit.zdb_id: 2008644-1
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