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  1. Yit KH, Zainal-Abidin Z
    Curr Top Med Chem, 2024;24(13):1158-1184.
    PMID: 38584545 DOI: 10.2174/0115680266294573240328050629
    AIMS: There has been increased scientific interest in bioactive compounds and their synthetic derivatives to promote the development of antimicrobial agents that could be used sustainably and overcome antibiotic resistance.

    METHODS: We conducted this scoping review to collect evidence related to the antimicrobial potential of diverse natural compounds from Zingiberaceae plants and their synthetic derivatives. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Extension for Scoping Reviews guidelines. The literature search was conducted using PubMed, Web of Science and Scopus electronic databases for relevant studies published from 2012 to 2023. A total of 28 scientific studies fulfilled the inclusion criteria. The authors of these studies implemented in vitro and in silico methods to examine the antimicrobial potency and underlying mechanisms of the investigated compounds.

    RESULT: The evidence elucidates the antimicrobial activity of natural secondary metabolites from Zingiberaceae species and their synthetic derivatives against a broad panel of gram-positive and gram-negative bacteria, fungi and viruses.

    CONCLUSION: To date, researchers have proposed the application of bioactive compounds derived from Zingiberaceae plants and their synthetic analogues as antimicrobial agents. Nevertheless, more investigations are required to ascertain their efficacy and to broaden their commercial applicability.

  2. Albowarab MH, Zakaria NA, Zainal Abidin Z
    Sensors (Basel), 2021 May 12;21(10).
    PMID: 34065920 DOI: 10.3390/s21103356
    Various aspects of task execution load balancing of Internet of Things (IoTs) networks can be optimised using intelligent algorithms provided by software-defined networking (SDN). These load balancing aspects include makespan, energy consumption, and execution cost. While past studies have evaluated load balancing from one or two aspects, none has explored the possibility of simultaneously optimising all aspects, namely, reliability, energy, cost, and execution time. For the purposes of load balancing, implementing multi-objective optimisation (MOO) based on meta-heuristic searching algorithms requires assurances that the solution space will be thoroughly explored. Optimising load balancing provides not only decision makers with optimised solutions but a rich set of candidate solutions to choose from. Therefore, the purposes of this study were (1) to propose a joint mathematical formulation to solve load balancing challenges in cloud computing and (2) to propose two multi-objective particle swarm optimisation (MP) models; distance angle multi-objective particle swarm optimization (DAMP) and angle multi-objective particle swarm optimization (AMP). Unlike existing models that only use crowding distance as a criterion for solution selection, our MP models probabilistically combine both crowding distance and crowding angle. More specifically, we only selected solutions that had more than a 0.5 probability of higher crowding distance and higher angular distribution. In addition, binary variants of the approaches were generated based on transfer function, and they were denoted by binary DAMP (BDAMP) and binary AMP (BAMP). After using MOO mathematical functions to compare our models, BDAMP and BAMP, with state of the standard models, BMP, BDMP and BPSO, they were tested using the proposed load balancing model. Both tests proved that our DAMP and AMP models were far superior to the state of the art standard models, MP, crowding distance multi-objective particle swarm optimisation (DMP), and PSO. Therefore, this study enables the incorporation of meta-heuristic in the management layer of cloud networks.
  3. Harun MY, Dayang Radiah AB, Zainal Abidin Z, Yunus R
    Bioresour Technol, 2011 Apr;102(8):5193-9.
    PMID: 21333529 DOI: 10.1016/j.biortech.2011.02.001
    Effects of different physical pretreatments on water hyacinth for dilute acid hydrolysis process (121 ± 3 °C, 5% H(2)SO(4), 60 min) were comparatively investigated. Untreated sample had produced 24.69 mg sugar/g dry matter. Steaming (121 ± 3 °C) and boiling (100 ± 3 °C) for 30 min had provided 35.9% and 52.4% higher sugar yield than untreated sample, respectively. The highest sugar yield (132.96 mg sugar/g dry matter) in ultrasonication was obtained at 20 min irradiation using 100% power. The highest sugar production (155.13 mg sugar/g dry matter) was obtained from pulverized samples. Hydrolysis time was reduced when using samples pretreated by drying, mechanical comminution and ultrasonication. In most methods, prolonging the pretreatment period was ineffective and led to sugar degradations. Morphology inspection and thermal analysis had provided evidences of structure disruption that led to higher sugar recovery in hydrolysis process.
  4. Samadi M, Zainal Abidin Z, Yoshida H, Yunus R, Awang Biak DR
    Molecules, 2020 Aug 26;25(17).
    PMID: 32858782 DOI: 10.3390/molecules25173872
    A method that delivers a high yield and excellent quality of essential oil, which retains most of its value-added compounds, and undergoes least change after the extraction process, is greatly sought after. Although chemical free methods are acceptable, they call for an extensive processing time, while the yield and quality from these methods are often disappointing. This work utilizes subcritical water technology to address these issues. In this undertaking, essential oil was extracted from Aquilaria malaccensis wood by way of subcritical conditions, and characterized through gas chromatography/mass spectroscopy (GC/MS). Optimization through response surface methodology revealed temperature to be the most critical factor for the extraction process, while the optimum conditions for temperature, sample-to-solvent ratio, and time for subcritical water extraction was revealed as 225 °C, 0.2 gr/mL, and 17 min, respectively. The subcritical water extraction technique involves two simultaneous processes, which are based on good fitting to the two-site kinetic and second order model. In comparison to the hydrodistillation method, GC/MS results indicated that the quality of A. malaccensis' wood oils, derived through the subcritical water technique, are of significantly better quality, while containing many constructive value-added compounds, such as furfural and guaiacol, which are useful for the production of pesticides and medicines. Pore size, functional groups, and morphology analysis revealed the occurrence of substantial damage to the samples, which facilitated an improved extraction of bio-products. In comparison to conventional methods, the use of the subcritical method not only involves a shorter processing time, but also delivers a higher oil yield and quality.
  5. Zainal Abidin ZA, Azizan N, Hayati F, Mra A, Mohd Azman ZA
    Kathmandu Univ Med J (KUMJ), 2018 7 1;16(63):272-274.
    PMID: 31719321
    Inflammatory myofibroblastic tumour is rare but more common in children. It shows an immunophenotypic features of myofibroblastic differentiation, hence bearing neoplastic potential. The diagnosis is challenging especially if it involves rectum. Surgical resection is the mainstay of treatment if clinically obstructed. A 65-year-old gentleman presented with intestinal obstruction, which then followed by a hartmann's procedure. Final diagnosis is a rare case of inflammatory myofibroblastic tumour of the rectum. We discuss its genetic involvement with a literature review.
  6. Azizan N, Mohd Said S, Zainal Abidin Z, Jantan I
    Molecules, 2017 Dec 05;22(12).
    PMID: 29206142 DOI: 10.3390/molecules22122135
    In this study, the essential oils of Orthosiphon stamineus Benth and Ficus deltoidea Jack were evaluated for their antibacterial activity against invasive oral pathogens, namely Enterococcus faecalis, Streptococcus mutans, Streptococcus mitis, Streptococcus salivarius, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Fusobacterium nucleatum. Chemical composition of the oils was analyzed using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The antibacterial activity of the oils and their major constituents were investigated using the broth microdilution method (minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC)). Susceptibility test, anti-adhesion, anti-biofilm, checkerboard and time-kill assays were also carried out. Physiological changes of the bacterial cells after exposure to the oils were observed under the field emission scanning electron microscope (FESEM). O. stamineus and F. deltoidea oils mainly consisted of sesquiterpenoids (44.6% and 60.9%, respectively), and β-caryophyllene was the most abundant compound in both oils (26.3% and 36.3%, respectively). Other compounds present in O. stamineus were α-humulene (5.1%) and eugenol (8.1%), while α-humulene (5.5%) and germacrene D (7.7%) were dominant in F. deltoidea. The oils of both plants showed moderate to strong inhibition against all tested bacteria with MIC and MBC values ranging 0.63-2.5 mg/mL. However, none showed any inhibition on monospecies biofilms. The time-kill assay showed that combination of both oils with amoxicillin at concentrations of 1× and 2× MIC values demonstrated additive antibacterial effect. The FESEM study showed that both oils produced significant alterations on the cells of Gram-negative bacteria as they became pleomorphic and lysed. In conclusion, the study indicated that the oils of O. stamineus and F. deltoidea possessed moderate to strong antibacterial properties against the seven strains pathogenic oral bacteria and may have caused disturbances of membrane structure or cell wall of the bacteria.
  7. Liew TK, Yong GY, Zainal Abidin Z, Asnir ZZ
    Malays J Med Sci, 2023 Jun;30(3):135-142.
    PMID: 37425384 DOI: 10.21315/mjms2023.30.3.12
    BACKGROUND: The article aims to study the demographics and clinical characteristics of ocular trauma patients presenting to the Eye Casualty Clinic between COVID-19 and non-COVID-19 era in Ampang Hospital, Malaysia.

    METHODS: In this cross-sectional study, data of patients presented with ocular trauma injury to the Ampang Hospital during the COVID-19 era from 18 March 2020 to 17 September 2020 were retrieved and compared with the similar period of the previous non-COVID-19 era year.

    RESULTS: Among the total number of 453 patients, 76.82% (n = 348) were predominantly males. The commonest age group was between 21 years old-40 years old (49.45%, n = 224), and the commonest location of ocular trauma injury occurred at the workplace (38.19%, n = 173); welding was the commonest work-related injury (13.83% in 2019; 12.50% in 2020). Injury-to-treatment time was significantly longer during the COVID-19 era, where patients who sought treatment within a day of injury were 27.27% (n = 69) in 2019 and 18.50% (n = 37) in 2020 (P = 0.030). During the COVID-19 pandemic, patients with vision worse than 6/60 on presentation were higher at 8% compared with 3.56% before the COVID-19 pandemic (OR = 2.35; 95% CI: 1.01, 5.48; P = 0.047). Similarly, patients with a vision worse than 6/60 post-treatment during the COVID-19 period were significantly higher at 7.00% compared with 1.58% before the COVID-19 pandemic (OR = 4.72; 95% CI: 1.53, 14.62; P = 0.007).

    CONCLUSION: The majority of ocular trauma cases in this study population were male adults between 21 years old and 40 years old, and welding was the commonest work-related injury. COVID-19 era has a higher percentage of patients presented with severe visual impairment, longer injury-to-treatment time and poorer post-treatment visual outcomes.

  8. Manuel AM, Kalimuthu S, Pathmanathan SS, Narayanan P, Zainal Abidin Z, Azmi K, et al.
    Asian J Surg, 2017 Apr;40(2):158-162.
    PMID: 24210537 DOI: 10.1016/j.asjsur.2013.09.011
    Arteriovenous malformations are congenital lesions that may evolve with time and manifest in a plethora of presentations. They can occur as torrential epistaxis when it extensively involves the facial region. Multi-imaging modalities are available to assist in characterizing the structure of the lesion as well as its location and extent. This complex disease requires a multidisciplinary team approach with preoperative embolization and surgery. We present a rare cause of life-threatening epistaxis in a gentleman with a longstanding orbital and hemifacial arteriovenous malformation and discuss the complexities involved in its management.
  9. Zentou H, Zainal Abidin Z, Yunus R, Awang Biak DR, Abdullah Issa M, Yahaya Pudza M
    ACS Omega, 2021 Feb 16;6(6):4137-4146.
    PMID: 33644536 DOI: 10.1021/acsomega.0c04025
    Despite the advantages of continuous fermentation whereby ethanol is selectively removed from the fermenting broth to reduce the end-product inhibition, this process can concentrate minor secondary products to the point where they become toxic to the yeast. This study aims to develop a new mathematical model do describe the inhibitory effect of byproducts on alcoholic fermentation including glycerol, lactic acid, acetic acid, and succinic acid, which were reported as major byproducts during batch alcoholic fermentation. The accumulation of these byproducts during the different stages of batch fermentation has been quantified. The yields of total byproducts, glycerol, acetic acid, and succinic acid per gram of glucose were 0.0442, 0.023, 0.0155, and 0.0054, respectively. It was found that the concentration of these byproducts linearly increases with the increase in glucose concentration in the range of 25-250 g/L. The results have also showed that byproduct concentration has a significant inhibitory effect on specific growth coefficient (μ) whereas no effect was observed on the half-velocity constant (Ks). A new mathematical model of alcoholic fermentation was developed considering the byproduct inhibitory effect, which showed a good performance and more accuracy compared to the classical Monod model.
  10. Mohd Ismail MR, Baharuddin KA, Zainal Abidin ZE, Abu Bakar MA, Sjahid AS
    Med J Malaysia, 2020 07;75(4):325-330.
    PMID: 32723989
    INTRODUCTION: Emergency department (ED) plays a main role in the initial management of patients who are critically ill. These patients require intra-hospital transfer for continuation of care. Adverse events can occur during this short duration and the distance of intra -hospital transfer. The aims of this study were to determine the incidence of adverse events during intrahospital transfer from ED and to determine the factors associated.

    METHODOLOGY: This was a cross-sectional observational study done from November 2017 until December 2017 at ED Hospital Sultan Abdul Halim (HSAH), a 650-bedded tertiary hospital in the state of Kedah. All patients that were triaged to red zone, age 18 years and above, and involved in intra-hospital transfer to critical coronary unit, intensive care unit and wards were included. All cases were documented in proforma by the accompanying staff.

    RESULTS: Among the 170 critically ill patients, only 29 patients (17.1%) experienced adverse events during intra-hospital transfer. The adverse events seen were hypotension (12.4%), desaturation (3.5%) and dislodged peripheral line (2.4%). Cardiorespiratory related diagnosis was the commonest presentation. Intra-hospital transfer during morning shift and evening shift has 79.5% (b=-1.59, OR=0.21, 95% CI: 0.06, 0.69, p=0.011) and 75.6% ((b=-1.41, OR=0.24, 95% CI: 0.08, 0.73, p=0.012) lesser odds of experiencing adverse events compare to night shift. Patients with vasopressor/inotropes had 9 times higher odds of experiencing adverse events during transportation, compared to patients with no vasopressor/inotropes (b=2.27, OR=9.70, 95% CI: 3.39, 27.72, p<0.001).

    CONCLUSIONS: Critical care patients who are involved in intrahospital transfer were at risk of adverse events such as hypotension, desaturation and dislodge peripheral line. Risk identification and maintaining level of care is important to minimize the adverse events during transfer. Patients had higher rates of adverse events if they were transferred during night shifts and on inotropic/vasopressor support.

  11. Abdulsalam M, Che Man H, Isma Idris A, Zainal Abidin Z, Faezah Yunos K
    PMID: 30304814 DOI: 10.3390/ijerph15102200
    Palm oil mill effluent contains carcinogenic coloured compounds that are difficult to separate due to their aromatic structure. Though colour treatment using adsorption processes at lower pH (<4) have been reported effectual, due to its acidity the remediated effluent poses an environmental hazard as a result. Thus, the current study focused on achieving decolourization at neutral pH by enhancing the morphology of the coconut shell activated carbon (CSAC) using N₂ as activating-agent with microwave irradiation heating. The microwave pretreated and non-pretreated CSAC were characterized using scanned electron microscopy (SEM), energy dispersive X-ray (EDX) and Brunauer-Emmett-Teller (BET) analysis. A significant modification in the porous structure with a 66.62% increase in the specific surface area was achieved after the pretreatment. The adsorption experimental matrix was developed using the central composite design to investigate the colour adsorption performance under varied pH (6⁻7), dosage (2⁻6 g) and contact time (10⁻100 min). At optimum conditions of neutral pH (7), 3.208 g dosage and contact time of 35 min, the percentage of colour removal was 96.29% with negligible differences compared with the predicted value, 95.855%. The adsorption equilibrium capacity of 1430.1 ADMI × mL/g was attained at the initial colour concentration of 2025 ADMI at 27 °C. The experimental data fitted better with the Freundlich isotherm model with R² 0.9851.
  12. Kamarudin N, Awang Biak DR, Zainal Abidin Z, Cardona F, Sapuan SM
    Materials (Basel), 2020 Jun 05;13(11).
    PMID: 32516968 DOI: 10.3390/ma13112578
    Heat explosions are sometimes observed during the synthesis of phenol formaldehyde (PF) resin. This scenario can be attributed to the high latent heat that was released and not dissipated leading to the occurrence of a runaway reaction. The synthesis temperature and time played important roles in controlling the heat release, hence preventing the resin from hardening during the synthesis process. This study aims to assess the rheological and viscoelasticity behaviors of the PF resin prepared using paraformaldehyde. The prepared PF resin was designed for laminate applications. The rheological behavior of the PF resin was assessed based on the different molar ratios of phenol to paraformaldehyde (P:F) mixed in the formulation. The molar ratios were set at 1.00:1.25, 1.00:1.50 and 1.00:1.75 of P to F, respectively. The rheological study was focused at specific synthesis temperatures, namely 40, 60, 80 and 100 °C. The synthesis time was observed for 240 min; changes in physical structure and viscosity of the PF resins were noted. It was observed that the viscosity values of the PF resins prepared were directly proportional to the synthesis temperature and the formaldehyde content. The PF resin also exhibited shear thickening behavior for all samples synthesized at 60 °C and above. For all PF resin samples synthesized at 60 °C and above, their viscoelasticity results indicated that the storage modulus (G'), loss modulus(G″) and tan δ are proportionally dependent on both the synthesis temperature and the formaldehyde content. Heat explosions were observed during the synthesis of PF resin at the synthesis temperature of 100 °C. This scenario can lead to possible runaway reaction which can also compromise the safety of the operators.
  13. Quek A, Mohd Zaini H, Kassim NK, Sulaiman F, Rukayadi Y, Ismail A, et al.
    PLoS One, 2021;16(5):e0251534.
    PMID: 33970960 DOI: 10.1371/journal.pone.0251534
    Melicope glabra (Blume) T. G. Hartley from the Rutaceae family is one of the richest sources of plant secondary metabolites, including coumarins and flavanoids. This study investigates the free radical scavenging and antibacterial activities of M. glabra and its isolated compounds. M. glabra ethyl acetate and methanol extracts were prepared using the cold maceration technique. The isolation of compounds was performed with column chromatography. The free radical scavenging activity of the extracts and isolated compounds were evaluated based on their oxygen radical absorbance capacity (ORAC) activities. The extracts and compounds were also subjected to antibacterial evaluation using bio-autographic and minimal inhibitory concentration (MIC) techniques against two oral pathogens, Enterococcus faecalis and Streptococcus mutans. Isolation of phytoconstituents from ethyl acetate extract successfully yielded quercetin 3, 5, 3'-trimethyl ether (1) and kumatakenin (2), while the isolation of the methanol extract resulted in scoparone (3), 6, 7, 8-trimethoxycoumarin (4), marmesin (5), glabranin (6), umbelliferone (7), scopoletin (8), and sesamin (9). The study is the first to isolate compound (1) from Rutaceae plants, and also the first to report the isolation of compounds (2-5) from M. glabra. The ORAC evaluation showed that the methanol extract is stronger than the ethyl acetate extract, while umbelliferone (7) exhibited the highest ORAC value of 24 965 μmolTE/g followed by glabranin (6), sesamin (9) and scopoletin (8). Ethyl acetate extract showed stronger antibacterial activity towards E. faecalis and S. mutans than the methanol extract with MIC values of 4166.7 ± 1443.4 μg/ml and 8303.3 ± 360.8 μg/ml respectively. Ethyl acetate extract inhibited E. faecalis growth, as shown by the lowest optical density value of 0.046 at a concentration of 5.0 mg/mL with a percentage inhibition of 95%. Among the isolated compounds tested, umbelliferone (7) and sesamin (9) exhibited promising antibacterial activity against S. mutans with both exhibiting MIC values of 208.3 ± 90.6 μg/ml. Findings from this study suggests M. glabra as a natural source of potent antioxidant and antibacterial agents.
  14. Zainal Abidin Z, Zainuren ZA, Noor E, Mohd Nor NS, Mohd Saffian S, Abdul Halim R
    Aust Dent J, 2021 03;66 Suppl 1:S15-S26.
    PMID: 33864280 DOI: 10.1111/adj.12845
    Diabetes mellitus (DM) is a complex metabolic disease characterized by hyperglycaemia resulted from defects in insulin secretion or action, or both. Various studies have reported on the bidirectional relationship between DM and periodontal disease. A systematic search of the literature was performed in several databases, EBSCO Medline Complete, PubMed, Science Direct and a manual search for articles from 2000 until 2019. Literature that fulfilled the inclusion criteria were identified, and data measuring plaque index (PI), gingival index (GI), clinical attachment loss (CAL) and periodontal probing depth (PPD) were extracted and subjected to Random-effects meta-analysis. From 947 titles and abstracts screened, 11 articles were included for meta-analysis. It was found that PI, GI, CAL and PPD were significantly higher in DM children than in non-DM children according to the Standardized Mean different (SMD) and 95% confidence intervals (CI) (SMD 0.54, 95% CI 0.20-0.87, P = 0.002; SMD 0.63, 95% CI 0.39-0.87, P 
  15. Kamuri MF, Zainal Abidin Z, Yaacob MH, Hamidon MN, Md Yunus NA, Kamarudin S
    Biosensors (Basel), 2019 Mar 14;9(1).
    PMID: 30875829 DOI: 10.3390/bios9010040
    This paper describes the development of an integrated system using a dry film resistant (DFR) microfluidic channel consisting of pulsed field dielectrophoretic field-flow-fractionation (DEP-FFF) separation and optical detection. The prototype chip employs the pulse DEP-FFF concept to separate the cells (Escherichia coli and Saccharomyces cerevisiae) from a continuous flow, and the rate of release of the cells was measured. The separation experiments were conducted by changing the pulsing time over a pulsing time range of 2⁻24 s and a flow rate range of 1.2⁻9.6 μ L min - 1 . The frequency and voltage were set to a constant value of 1 M Hz and 14 V pk-pk, respectively. After cell sorting, the particles pass the optical fibre, and the incident light is scattered (or absorbed), thus, reducing the intensity of the transmitted light. The change in light level is measured by a spectrophotometer and recorded as an absorbance spectrum. The results revealed that, generally, the flow rate and pulsing time influenced the separation of E. coli and S. cerevisiae. It was found that E. coli had the highest rate of release, followed by S. cerevisiae. In this investigation, the developed integrated chip-in-a lab has enabled two microorganisms of different cell dielectric properties and particle size to be separated and subsequently detected using unique optical properties. Optimum separation between these two microorganisms could be obtained using a longer pulsing time of 12 s and a faster flow rate of 9.6 μ L min - 1 at a constant frequency, voltage, and a low conductivity.
  16. Yahaya Pudza M, Zainal Abidin Z, Abdul Rashid S, Md Yasin F, Noor ASM, Issa MA
    Nanomaterials (Basel), 2020 Feb 12;10(2).
    PMID: 32059384 DOI: 10.3390/nano10020315
    The materials and substances required for sustainable water treatment by adsorption technique, are still being researched widely by distinguished classes of researchers. Thus, the need to synthesize substances that can effectively clean up pollutants from the environment cannot be overemphasized. So far, materials in bulk forms that are rich in carbon, such as biochar and varieties of activated carbon have been used for various adsorptive purposes. The use of bulk materials for such purposes are not efficient due to minimal surface areas available for adsorption. This study explores the adsorption task at nano dimension using carbon dots (CDs) from tapioca. The properties of carbon structure and its influence on the adsorptive efficacy of carbon nanoparticles were investigated by energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), high resolution transmission electron microscopy (HrTEM), and atomic force microscopy (AFM). The results implied carbon present in CDs are good adsorbents for effective adsorption of heavy metal ions (lead) with removal efficiency of 80.6% in aqueous environment. The adsorption process as explored by both Langmuir and Freundlich isotherms have proven favorability of the adsorption process. Langmuir form two and three have correlation coefficients R2 at 0.9922 and 0.9912, respectively. The Freundlich isotherm confirms CDs as having defined surface heterogeneity and the exponential distribution of active sites. The adsorption of lead unto CDs obeyed the second order kinetic model with coefficient of determination, R2 of 0.9668 and 0.9996 at an initial lead concentration of 20 mg/L and 100 mg/L, respectively. The findings validated the efficiency of CDs derived from tapioca as an excellent material for further utilization in the environmental fields of wastewater pollution detection and clean up, bio-imaging, and chemical sensing applications.
  17. Ali Esmail B, Majid HA, Zainal Abidin Z, Haimi Dahlan S, Himdi M, Dewan R, et al.
    Materials (Basel), 2020 Jan 26;13(3).
    PMID: 31991912 DOI: 10.3390/ma13030582
    In this research, a reconfigurable metamaterial (MM) structure was designed using a millimeter-wave (MMW) band with two configurations that exhibit different refractive indices. These two MM configurations are used to guide the antenna's main beam in the desired direction in the 5th generation (5G) band of 28 GHz. The different refractive indices of the two MM configurations created phase change for the electromagnetic (EM) wave of the antenna, which deflected the main beam. A contiguous squares resonator (CSR) is proposed as an MM structure to operate at MMW band. The CSR is reconfigured using three switches to achieve two MM configurations with different refractive indices. The simulation results of the proposed antenna loaded by MM unit cells demonstrate that the radiation beam is deflected by angles of +30° and -27° in the E-plane, depending on the arrangement of the two MM configurations on the antenna substrate. Furthermore, these deflections are accompanied by gain enhancements of 1.9 dB (26.7%) and 1.5 dB (22.4%) for the positive and negative deflections, respectively. The reflection coefficients of the MM antenna are kept below -10 dB for both deflection angles at 28 GHz. The MM antennas are manufactured and measured to validate the simulated results.
  18. Abdulsalam M, Che Man H, Goh PS, Yunos KF, Zainal Abidin Z, Isma M I A, et al.
    Polymers (Basel), 2020 Mar 03;12(3).
    PMID: 32138186 DOI: 10.3390/polym12030549
    This study focused on developing a hydrophilic hybrid polyvinylidene fluoride (PVDF)-polyethylene glycol (PEG) hollow membrane by incorporating Nano-magnesium oxide (NMO) as a potent antifouling mediator. The Nano-hybrid hollow fibers with varied loading of NMO (0 g; 0.25 g; 0.50 g; 0.75 g and 1.25 g) were spun through phase inversion technique. The resultants Nano-hybrid fibers were characterized and compared based on SEM, EDX, contact angle, surface zeta-potential, permeability flux, fouling resistance and color rejection from palm oil mill effluent (POME). Noticeably, the permeability flux, fouling resistance and color rejection improved with the increase in NMO loading. PVDF-PEG with 0.50 g-NMO loading displayed an outstanding performance with 198.35 L/m2·h, 61.33 L/m2·h and 74.65% of water flux, POME flux and color rejection from POME, respectively. More so, a remarkable fouling resistance were obtained such that the flux recovery, reversible fouling percentage and irreversible fouling percentage remains relatively steady at 90.98%, 61.39% and 7.68%, respectively, even after 3 cycles of continuous filtrations for a total period of 9 h. However, at excess loading of 0.75 and 1.25 g-NMO, deterioration in the flux and fouling resistance was observed. This was due to the agglomeration of nanoparticles within the matrix structure at the excessive loading.
  19. Zainal Abidin Z, Noor E, Mohd Nor NS, Mohamed Nazari NS, Anuar Zaini A, Azizi NZ, et al.
    Eur J Dent, 2023 Dec 04.
    PMID: 38049120 DOI: 10.1055/s-0043-1772777
    OBJECTIVES:  The study aimed to evaluate type 1 diabetes mellitus (T1DM) patients' self-perceived periodontal health status and to identify the association between periodontal disease (PD) and DM.

    MATERIALS AND METHODS:  This cross-sectional study included 113 T1DM children between 3 and 18 years old from the Universiti Teknologi MARA and the University of Malaya. Periodontal health parameters, including plaque index, gingival index, probing pocket depth, simplified basic periodontal examination, and clinical attachment loss, were recorded. Self-perceived periodontal health status was assessed with questionnaires.

    STATISTICAL ANALYSIS:  Statistical analysis was performed to evaluate the sensitivity of the questionnaire and the relationship between T1DM and periodontal parameters.

    RESULTS:  The median age was 11.4 years. Half of them (50.4%) were females. A total of 83.5% rated their oral condition as good, whereas 27.5% reported a history of gingival bleeding. Clinical examination revealed that 48.7% had healthy gingiva, whereas 47.8% had gingivitis. The question "Do you have bleeding when brushing, flossing, or eating food?" showed good accuracy in the evaluation of PD (p 

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