Displaying publications 1 - 20 of 401 in total

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  1. Khan A, Ab Ghani S
    Biosens Bioelectron, 2012 Jan 15;31(1):433-8.
    PMID: 22154168 DOI: 10.1016/j.bios.2011.11.007
    The electrochemical biosensors based on poly(o-phenylenediamine) (PoPD) and acetylcholinesterase (AChE) and choline oxidase (ChO) enzymes were fabricated on carbon fibre (CF) substrate. The electropolymerized PoPD was used to reduce the interfering substances. The electrode assembly was completed by depositing functionalized carbon nano tubes (FCNTs) and Nafion (Naf). Amperometric detection of acetylcholine (ACh) and choline (Ch) were realized at an applied potential of +750 mV vs Ag/AgCl (saturated KCl). At pH 7.4, the final assembly, Naf-FCNTs/AChE-ChO((10:1))/PoPD/CF(Elip), was observed to have high sensitivity towards Ch (6.3±0.3 μA mM(-1)) and ACh (5.8±0.3 μA mM(-1)), linear range for Ch (K(M)=0.52±0.03 mM) and ACh (K(M)=0.59±0.07 mM), and for Ch the highest ascorbic acid blocking capacity (97.2±2 1mM AA). It had a response time of <5s and with 0.045 μM limit of detection. Studies on different ratio (ACh/Ch) revealed that 10:1, gave best overall response.
    Matched MeSH terms: Equipment Design
  2. Ahmad F, Yusof AP, Bainbridge M, Ab Ghani S
    Biosens Bioelectron, 2008 Jul 15;23(12):1862-8.
    PMID: 18440218 DOI: 10.1016/j.bios.2008.03.006
    The mechanisms involving insulin and anti-hypertensive drugs regulation for in vivo cerebral glucose metabolism are not well-understood. This might be due to lack of direct means of measuring cerebral glucose. It is known that the continuous delivery of glucose to the brain is critical for its normal metabolic function. In this study, we report the effect of insulin and anti-hypertensive drugs on glucose level in the striatum of rats. The rats were divided into two groups, i.e. hyperglycemia (14.8+/-0.3mM plasma glucose) and diabetic (10.8+/-0.2mM plasma glucose). A custom-built glucose microsensor was implanted at coordinates A/P 1.0 from bregma, M/L +2.5 and D/V -5.0 (from dura) in the striatum. The amperometric response obtained at +0.23 V vs. Ag|AgCl corresponded to the glucose level in striatum. By varying the concentrations of protaminc zinc insulin infused into the rats, striatum glucose level was found to remain constant throughout, i.e. 9.8+/-0.1 and 4.7+/-0.1mM for hyperglycemic rats and for diabetic rats, respectively. However, infusion of valsartan and felodipine has lowered the striatum glucose level significantly. These findings agreed with the hypothesis that suggested striatum glucose uptake do not depend on insulin but is clearly dependant on anti-hypertensive drugs administration.
    Matched MeSH terms: Equipment Design
  3. Kumar Sinasamy T, Nazaruddin Wan Hassan WM, Hardy Mohamad Zaini R, Seevaunnamtum P, Ab Mukmin L
    Anaesthesiol Intensive Ther, 2020;52(5):383-388.
    PMID: 33327696 DOI: 10.5114/ait.2020.101407
    INTRODUCTION: The Baska mask and i-gel are two new types of second-generation supraglottic airway devices. The aim of this study was to compare these two devices in terms of quality of insertion, quality of ventilation and post-insertion complications.

    MATERIAL AND METHODS: A total of 80 adult patients who were scheduled for elective surgery under general anaesthesia were randomised to two groups: Group BM: Baska mask (n = 40) and Group IG: i-gel (n = 40). The assessment focused on ease of insertion, number of attempts, insertion time, number of corrective manoeuvres, oropharyngeal leak pressure, tidal volume, peak airway pressure (PAP) and post-insertion complications.

    RESULTS: Group IG showed a significantly shorter median insertion time (13.3 [interquartile range, IQR 7.8] vs. 17.0 [IQR 9.6] s; P < 0.001), a higher percentage in the 'very easy' ease of insertion category (62.5% vs. 10.0%; P < 0.001), a higher percentage in the no corrective manoeuvre category (92.5% vs. 72.5%; P = 0.003) and a higher percentage in the no post-operative throat pain category (67.5% vs. 32.5%; P = 0.011) than Group BM. However, Group BM showed a significantly higher generated PAP than Group IG (12.7 [1.8] and 11.5 [2.2] cm H2O, respectively; P = 0.010). There were no significant differences in other parameters.

    CONCLUSIONS: The i-gel was better than the Baska mask in terms of ease of insertion, speed of insertion, fewer corrective manoeuvres and less post-operative throat pain. However, the Baska mask had a better cuff seal, as shown by a higher generated PAP.

    Matched MeSH terms: Equipment Design
  4. Kadirgama K, Noor MM, Abd Alla AN
    Sensors (Basel), 2010;10(3):2054-63.
    PMID: 22294914 DOI: 10.3390/s100302054
    Metal cutting processes are important due to increased consumer demands for quality metal cutting related products (more precise tolerances and better product surface roughness) that has driven the metal cutting industry to continuously improve quality control of metal cutting processes. This paper presents optimum surface roughness by using milling mould aluminium alloys (AA6061-T6) with Response Ant Colony Optimization (RACO). The approach is based on Response Surface Method (RSM) and Ant Colony Optimization (ACO). The main objectives to find the optimized parameters and the most dominant variables (cutting speed, feedrate, axial depth and radial depth). The first order model indicates that the feedrate is the most significant factor affecting surface roughness.
    Matched MeSH terms: Equipment Design/methods*
  5. Muhamad MH, Sheikh Abdullah SR, Abu Hasan H, Abd Rahim RA
    J Environ Manage, 2015 Nov 1;163:115-24.
    PMID: 26311084 DOI: 10.1016/j.jenvman.2015.08.012
    The complexity of residual toxic organics from biologically treated effluents of pulp and paper mills is a serious concern. To date, it has been difficult to choose the best treatment technique because each of the available options has advantages and drawbacks. In this study, two different treatment techniques using laboratory-scale aerobic sequencing batch reactors (SBRs) were tested with the same real recycled paper mill effluent to evaluate their treatment efficiencies. Two attached-growth SBRs using granular activated carbon (GAC) with and without additional biomass and a suspended-growth SBR were used in the treatment of real recycled paper mill effluent at a chemical oxygen demand (COD) level in the range of 800-1300 mg/L, a fixed hydraulic retention time of 24 h and a COD:N:P ratio of approximately 100:5:1. The efficiency of this biological treatment process was studied over a 300-day period. The six most important wastewater quality parameters, namely, chemical oxygen demand (COD), turbidity, ammonia (expressed as NH3-N), phosphorus (expressed as PO4(3)-P), colour, and suspended solids (SS), were measured to compare the different treatment techniques. It was determined that these processes were able to almost completely and simultaneously eliminate COD (99%) and turbidity (99%); the removals of NH3-N (90-100%), PO4(3)-P (66-78%), colour (63-91%), and SS (97-99%) were also sufficient. The overall performance results confirmed that an attached-growth SBR system using additional biomass on GAC is a promising configuration for wastewater treatment in terms of performance efficiency and process stability under fluctuations of organic load. Hence, this hybrid system is recommended for the treatment of pulp and paper mill effluents.
    Matched MeSH terms: Equipment Design
  6. Ab Wahab N, Mohd Salleh MK, Ismail Khan Z, Abd Rashid NE
    ScientificWorldJournal, 2014;2014:671369.
    PMID: 25121132 DOI: 10.1155/2014/671369
    Reconfigurable ring filter based on single-side-access ring topology is presented. Using capacitive tuning elements, the electrical length of the ring can be manipulated to shift the nominal center frequency to a desired position. A synthesis is developed to determine the values of the capacitive elements. To show the advantage of the synthesis, it is applied to the reconfigurable filter design using RF lumped capacitors. The concept is further explored by introducing varactor-diodes to continuously tune the center frequency of the ring filter. For demonstration, two prototypes of reconfigurable ring filters are realized using microstrip technology, simulated, and measured to validate the proposed concept. The reconfigured filter using lumped elements is successfully reconfigured from 2 GHz to 984.4 MHz and miniaturized by 71% compared to the filter directly designed at the same reconfigured frequency, while, for the filter using varactor-diodes, the frequency is chosen from 1.10 GHz to 1.38 GHz spreading over 280 MHz frequency range. Both designs are found to be compact with acceptable insertion loss and high selectivity.
    Matched MeSH terms: Equipment Design
  7. Ibrahim S, Green RG, Dutton K, Abdul Rahim R
    ISA Trans, 2002 Jan;41(1):13-8.
    PMID: 12014798
    This paper describes a system using lensed optical fiber sensors that are arranged in the form of two orthogonal projections. The sensors are placed around a process vessel for upstream and downstream measurements. The purpose of the system is for on-line monitoring of particles and droplets being conveyed by a fluid. The lenses were constructed using a custom heating fixture. The fixture enables the lenses to be constructed with similar radii resulting in identical characteristics with minimum differences in transmitted intensity and emission angle. By collimating radiation from two halogen bulbs, radiation can be obtained by the sensors with radiation intensity related to the nature of the media. Each sensor interrogates a finite section of the measurement section. Each sensor provides a view. Parallel sensors provide a projection. Signal processing is carried out on the measured data in the time and frequency domains to investigate the latent information present in the flow signals.
    Matched MeSH terms: Equipment Design
  8. Yahaya ML, Zakaria ND, Noordin R, Abdul Razak K
    Biotechnol Appl Biochem, 2021 Oct;68(5):1095-1106.
    PMID: 32935878 DOI: 10.1002/bab.2029
    Salmonella and Shigella genera are common pathogens that contaminate foods and beverages. Lateral flow assays (LFA) are commonly used to detect these pathogens. However, most of the developed LFAs are for single detection. Simultaneous detection of pathogens is required to reduce cost and time. In this work, 40 nm gold nanoparticles (AuNPs) were synthesized using the seeding growth method as labeling agent. The AuNPs were characterized and conjugated with mouse anti-Gram negative endotoxin antibody. The nitrocellulose membrane HF135 was immobilized with anti-mouse IgG antibody as a control line and two separate test lines with either anti-Shigella or anti-Salmonella antibody, respectively. Color intensity of test lines was observed for positive samples. A milk sample was used as proof of concept to mimic actual contamination. The limit of detection of the LFA was 3.0 × 106 CFU/mL for multiplex detection of Shigella flexneri and Salmonella Typhi and for both single detections. The result was comparable with the enzyme-linked immunosorbent assay (ELISA) analysis. The produced LFA could differentiate between Shigella flexneri, Shigella boydii, Salmonella Enteritidis, and Salmonella Typhi. The developed LFA was able to identify Shigella flexneri and Salmonella Typhi with good sensitivity in milk samples, thus, beneficial to ensure the safety of food before entering the market.
    Matched MeSH terms: Equipment Design
  9. Li Y, Ghazilla RAR, Abdul-Rashid SH
    Int J Environ Res Public Health, 2022 Oct 22;19(21).
    PMID: 36360620 DOI: 10.3390/ijerph192113742
    In the current situation of global aging, the current market shortage of age-appropriate smart home products and the recent epidemic have led to greater isolation of the elderly, seriously affecting their physical and mental health. In order to optimize the sustainable user experience of the elderly when using smart home products, this paper proposes a research method based on Quality Function Deployment (QFD) for the optimal design of user experience of smart home products for the elderly, taking the design of age-appropriate home smart refrigerators as an example. Firstly, based on the results of market research and user interviews, the requirements of smart refrigerators for the elderly are screened and integrated, and the Kano model is used to prioritize these needs, resulting in the identification of important features needed in smart refrigerators for the elderly. Secondly, based on QFD, user requirements are transformed into design requirements, and a quality house model is established to ascertain the degree of importance of each design requirement through user ratings so as to obtain the key requirements as the theoretical basis for the solution design. Finally, optional solutions are generated for concept evaluation based on PUGH concept selection, comparing the advantages and disadvantages of the solutions and recombining them into an evaluation to determine the best solution. The quantitative evaluation of the four solutions reveals that Solution A has the highest score of 117.358, followed by Solution D with 113.259, Solution B with 96.415, and Solution C with 85.511, which is the lowest. The scoring allows the best design solution to be selected and applied to product development. The results show that the introduction of the Kano model and PUGH concept selection into QFD can be effectively used as a research method for optimizing the user experience of smart refrigerators for the elderly, and a corresponding design strategy for sustainable user experience optimization is proposed. The method and strategy provide guidance for the innovative design of new smart home products.
    Matched MeSH terms: Equipment Design*
  10. Moradihamedani P, Abdullah AH
    Water Sci Technol, 2018 Jan;77(1-2):346-354.
    PMID: 29377819 DOI: 10.2166/wst.2017.545
    Removal of low-concentration ammonia (1-10 ppm) from aquaculture wastewater was investigated via polysulfone (PSf)/zeolite mixed matrix membrane. PSf/zeolite mixed matrix membranes with different weight ratios (90/10, 80/20, 70/30 and 60/40 wt.%) were prepared and characterized. Results indicate that PSf/zeolite (80/20) was the most efficient membrane for removal of low-concentration ammonia. The ammonia elimination by PSf/zeolite (80/20) from aqueous solution for 10, 7, 5, 3 and 1 ppm of ammonia was 100%, 99%, 98.8%, 96% and 95% respectively. The recorded results revealed that pure water flux declined in higher loading of zeolite in the membrane matrix due to surface pore blockage caused by zeolite particles. On the other hand, ammonia elimination from water was decreased in higher contents of zeolite because of formation of cavities and macrovoids in the membrane substructure.
    Matched MeSH terms: Equipment Design
  11. Abdullah MZ, Awang MS, Tan YC, Abdullah JM
    J Neurol Surg A Cent Eur Neurosurg, 2014 Mar;75(2):155-7.
    PMID: 23636911 DOI: 10.1055/s-0032-1330954
    The study assesses the capability and accuracy of a robotic arm to perform burr holes.
    Matched MeSH terms: Equipment Design
  12. Dabbagh A, Abdullah BJ, Ramasindarum C, Abu Kasim NH
    Ultrason Imaging, 2014 Oct;36(4):291-316.
    PMID: 24626566 DOI: 10.1177/0161734614526372
    Tissue-mimicking phantoms that are currently available for routine biomedical applications may not be suitable for high-temperature experiments or calibration of thermal modalities. Therefore, design and fabrication of customized thermal phantoms with tailored properties are necessary for thermal therapy studies. A multitude of thermal phantoms have been developed in liquid, solid, and gel forms to simulate biological tissues in thermal therapy experiments. This article is an attempt to outline the various materials and techniques used to prepare thermal phantoms in the gel state. The relevant thermal, electrical, acoustic, and optical properties of these phantoms are presented in detail and the benefits and shortcomings of each type are discussed. This review could assist the researchers in the selection of appropriate phantom recipes for their in vitro study of thermal modalities and highlight the limitations of current phantom recipes that remain to be addressed in further studies.
    Matched MeSH terms: Equipment Design
  13. Mahdi MA, Sheih SJ, Adikan FR
    Opt Express, 2009 Jun 08;17(12):10069-75.
    PMID: 19506658
    We demonstrate a simplified algorithm to manifest the contribution of amplified spontaneous emission in variable gain-flattened Erbium-doped fiber amplifier (EDFA). The detected signal power at the input and output ports of EDFA comprises of both signal and noise. The generated amplified spontaneous emission from EDFA cannot be differentiated by photodetector which leads to underestimation of the targeted gain value. This gain penalty must be taken into consideration in order to obtain the accurate gain level. By taking the average gain penalty within the dynamic gain range, the targeted output power is set higher than the desired level. Thus, the errors are significantly reduced to less than 0.15 dB from 15 dB to 30 dB desired gain values.
    Matched MeSH terms: Equipment Design
  14. Rifat AA, Mahdiraji GA, Chow DM, Shee YG, Ahmed R, Adikan FR
    Sensors (Basel), 2015;15(5):11499-510.
    PMID: 25996510 DOI: 10.3390/s150511499
    We propose a surface plasmon resonance (SPR) sensor based on photonic crystal fiber (PCF) with selectively filled analyte channels. Silver is used as the plasmonic material to accurately detect the analytes and is coated with a thin graphene layer to prevent oxidation. The liquid-filled cores are placed near to the metallic channel for easy excitation of free electrons to produce surface plasmon waves (SPWs). Surface plasmons along the metal surface are excited with a leaky Gaussian-like core guided mode. Numerical investigations of the fiber's properties and sensing performance are performed using the finite element method (FEM). The proposed sensor shows maximum amplitude sensitivity of 418 Refractive Index Units (RIU-1) with resolution as high as 2.4 × 10(-5) RIU. Using the wavelength interrogation method, a maximum refractive index (RI) sensitivity of 3000 nm/RIU in the sensing range of 1.46-1.49 is achieved. The proposed sensor is suitable for detecting various high RI chemicals, biochemical and organic chemical analytes. Additionally, the effects of fiber structural parameters on the properties of plasmonic excitation are investigated and optimized for sensing performance as well as reducing the sensor's footprint.
    Matched MeSH terms: Equipment Design
  15. Al-Fakih EA, Osman NA, Eshraghi A, Adikan FR
    Sensors (Basel), 2013 Aug 12;13(8):10348-57.
    PMID: 23941909 DOI: 10.3390/s130810348
    This study presents the first investigation into the capability of fiber Bragg grating (FBG) sensors to measure interface pressure between the stump and the prosthetic sockets of a trans-tibial amputee. FBG element(s) were recoated with and embedded in a thin layer of epoxy material to form a sensing pad, which was in turn embedded in a silicone polymer material to form a pressure sensor. The sensor was tested in real time by inserting a heavy-duty balloon into the socket and inflating it by using an air compressor. This test was conducted to examine the sensitivity and repeatability of the sensor when subjected to pressure from the stump of the trans-tibial amputee and to mimic the actual environment of the amputee's Patellar Tendon (PT) bar. The sensor exhibited a sensitivity of 127 pm/N and a maximum FSO hysteresis of around ~0.09 in real-time operation. Very good reliability was achieved when the sensor was utilized for in situ measurements. This study may lead to smart FBG-based amputee stump/socket structures for pressure monitoring in amputee socket systems, which will result in better-designed prosthetic sockets that ensure improved patient satisfaction.
    Matched MeSH terms: Equipment Design
  16. Mohajeri S, Aziz HA, Isa MH, Zahed MA, Bashir MJ, Adlan MN
    Water Sci Technol, 2010;61(5):1257-66.
    PMID: 20220248 DOI: 10.2166/wst.2010.018
    In the present study, Electrochemical Oxidation was used to remove COD and color from semi-aerobic landfill leachate collected from Pulau Burung Landfill Site (PBLS), Penang, Malaysia. Experiments were conducted in a batch laboratory-scale system in the presence of NaCl as electrolyte and aluminum electrodes. Central composite design (CCD) under Response surface methodology (RSM) was applied to optimize the electrochemical oxidation process conditions using chemical oxygen demand (COD) and color removals as responses, and the electrolyte concentrations, current density and reaction time as control factors. Analysis of variance (ANOVA) showed good coefficient of determination (R(2)) values of >0.98, thus ensuring satisfactory fitting of the second-order regression model with the experimental data. In un-optimized condition, maximum removals for COD (48.77%) and color (58.21%) were achieved at current density 80 mA/cm(2), electrolyte concentration 3,000 mg/L and reaction time 240 min. While after optimization at current density 75 mA/cm(2), electrolyte concentration 2,000 mg/L and reaction time 218 min a maximum of 49.33 and 59.24% removals were observed for COD and color respectively.
    Matched MeSH terms: Equipment Design
  17. Othman N, Kamarudin SK, Takriff MS, Rosli MI, Engku Chik EM, Adnan MA
    ScientificWorldJournal, 2014;2014:242658.
    PMID: 24741344 DOI: 10.1155/2014/242658
    Radiotracer experiments are carried out in order to determine the mean residence time (MRT) as well as percentage of dead zone, V dead (%), in an integrated mixer consisting of Rushton and pitched blade turbine (PBT). Conventionally, optimization was performed by varying one parameter and others were held constant (OFAT) which lead to enormous number of experiments. Thus, in this study, a 4-factor 3-level Taguchi L9 orthogonal array was introduced to obtain an accurate optimization of mixing efficiency with minimal number of experiments. This paper describes the optimal conditions of four process parameters, namely, impeller speed, impeller clearance, type of impeller, and sampling time, in obtaining MRT and V dead (%) using radiotracer experiments. The optimum conditions for the experiments were 100 rpm impeller speed, 50 mm impeller clearance, Type A mixer, and 900 s sampling time to reach optimization.
    Matched MeSH terms: Equipment Design
  18. Lim JW, Lim PE, Seng CE, Adnan R
    Bioresour Technol, 2013 Feb;129:485-94.
    PMID: 23266850 DOI: 10.1016/j.biortech.2012.11.111
    Moving bed sequencing batch reactors (MBSBRs) packed with 8% (v/v) of 8-, 27- and 64-mL polyurethane (PU) foam cubes, respectively, were investigated for simultaneous 4-chlorophenol (4-CP) and nitrogen removal at increasing 4-CP concentration. When the 4-CP concentration exceeded 300 mg L(-1), the MBSBR with 27-mL foam cubes was observed to outperform the other MBSBRs in removing 4-CP and nitrogen. The reasons were: (1) there were more biomass in inner layer of the 27-mL cubes, compared to that of the 8-mL cubes, which was more shielded from the inhibitory effect of 4-CP and (2) the 27-mL cubes were more mobile than the 64-mL cubes. Although increasing 4-CP concentration to 600 mg L(-1) resulted in incomplete removal of 4-CP in the MBSBRs, results of the batch reactor with 27-mL foam cubes showed that complete 4-CP removal within the REACT period could be achieved by increasing the packing volume to 20%.
    Matched MeSH terms: Equipment Design
  19. Rahman HA, Harun SW, Arof H, Irawati N, Musirin I, Ibrahim F, et al.
    J Biomed Opt, 2014 May;19(5):057009.
    PMID: 24839996 DOI: 10.1117/1.JBO.19.5.057009
    An enhanced dental cavity diameter measurement mechanism using an intensity-modulated fiber optic displacement sensor (FODS) scanning and imaging system, fuzzy logic as well as a single-layer perceptron (SLP) neural network, is presented. The SLP network was employed for the classification of the reflected signals, which were obtained from the surfaces of teeth samples and captured using FODS. Two features were used for the classification of the reflected signals with one of them being the output of a fuzzy logic. The test results showed that the combined fuzzy logic and SLP network methodology contributed to a 100% classification accuracy of the network. The high-classification accuracy significantly demonstrates the suitability of the proposed features and classification using SLP networks for classifying the reflected signals from teeth surfaces, enabling the sensor to accurately measure small diameters of tooth cavity of up to 0.6 mm. The method remains simple enough to allow its easy integration in existing dental restoration support systems.
    Matched MeSH terms: Equipment Design
  20. Yang HZ, Lim KS, Qiao XG, Chong WY, Cheong YK, Lim WH, et al.
    Opt Express, 2013 Jun 17;21(12):14808-15.
    PMID: 23787668 DOI: 10.1364/OE.21.014808
    We present a new theoretical model for the broadband reflection spectra of etched FBGs which includes the effects of axial contraction and stress-induced index change. The reflection spectra of the etched FBGs with several different taper profiles are simulated based on the proposed model. In our observation, decaying exponential profile produces a broadband reflection spectrum with good uniformity over the range of 1540-1560 nm. An etched FBG with similar taper profile is fabricated and the experimental result shows good agreement with the theoretical model.
    Matched MeSH terms: Equipment Design
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