Displaying publications 1 - 20 of 399 in total

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  1. Zulkepli SNIS, Hamid NH, Shukla V
    Biosensors (Basel), 2018 May 08;8(2).
    PMID: 29738428 DOI: 10.3390/bios8020045
    In recent years, the number of interdisciplinary research works related to the development of miniaturized systems with integrated chemical and biological analyses is increasing. Digital microfluidic biochips (DMFBs) are one kind of miniaturized systems designed for conducting inexpensive, fast, convenient and reliable biochemical assay procedures focusing on basic scientific research and medical diagnostics. The role of a dielectric layer in the digital microfluidic biochips is prominent as it helps in actuating microliter droplets based on the electrowetting-on-dielectric (EWOD) technique. The advantages of using three different material layers of dielectric such as parafilm, polytetrafluoroethylene (PTFE) and ethylene tetrafluoroethylene (ETFE) were reported in the current work. A simple fabrication process of a digital microfluidic device was performed and good results were obtained. The threshold of the actuation voltage was determined for all dielectric materials of varying thicknesses. Additionally, the OpenDrop device was tested by utilizing a single-plate system to transport microliter droplets for a bioassay operation. With the newly proposed fabrication methods, these dielectric materials showed changes in contact angle and droplet velocity when the actuation voltage was applied. The threshold actuation voltage for the dielectric layers of 10⁻13 μm was 190 V for the open plate DMFBs.
    Matched MeSH terms: Equipment Design
  2. Zulfiqar MA, Noryati M, Hamzaini AH, Thambidorai CR
    Med J Malaysia, 2006 Jun;61(2):199-203.
    PMID: 16898311 MyJurnal
    The purpose of this study was to determine the effectiveness of pneumatic reduction of intussusception using equipment readily available in the hospital. Twenty-two children aged between four months and four years had pneumatic reduction of intussusception. The device used was assembled using (i) a hand-held pump attached to a pressure gauge, and (ii) a 3-way Foley's balloon catheter. There was a 73% success rate and there were no complications. The device used was effective and safe for the pneumatic reduction of intussusception.
    Matched MeSH terms: Equipment Design
  3. Zubair S, Fisal N, Baguda YS, Saleem K
    Sensors (Basel), 2013;13(10):13005-38.
    PMID: 24077319 DOI: 10.3390/s131013005
    Interest in the cognitive radio sensor network (CRSN) paradigm has gradually grown among researchers. This concept seeks to fuse the benefits of dynamic spectrum access into the sensor network, making it a potential player in the next generation (NextGen) network, which is characterized by ubiquity. Notwithstanding its massive potential, little research activity has been dedicated to the network layer. By contrast, we find recent research trends focusing on the physical layer, the link layer and the transport layers. The fact that the cross-layer approach is imperative, due to the resource-constrained nature of CRSNs, can make the design of unique solutions non-trivial in this respect. This paper seeks to explore possible design opportunities with wireless sensor networks (WSNs), cognitive radio ad-hoc networks (CRAHNs) and cross-layer considerations for implementing viable CRSN routing solutions. Additionally, a detailed performance evaluation of WSN routing strategies in a cognitive radio environment is performed to expose research gaps. With this work, we intend to lay a foundation for developing CRSN routing solutions and to establish a basis for future work in this area.
    Matched MeSH terms: Equipment Design
  4. Zen DI, Saidin N, Damanhuri SS, Harun SW, Ahmad H, Ismail MA, et al.
    Appl Opt, 2013 Feb 20;52(6):1226-9.
    PMID: 23434993 DOI: 10.1364/AO.52.001226
    We demonstrate mode locking of a thulium-bismuth codoped fiber laser (TBFL) operating at 1901.6 nm, using a graphene-based saturable absorber (SA). In this work, a single layer graphene is mechanically exfoliated using the scotch tape method and directly transferred onto the surface of a fiber pigtail to fabricate the SA. The obtained Raman spectrum characteristic indicates that the graphene on the core surface has a single layer. At 1552 nm pump power of 869 mW, the mode-locked TBFL self starts to generate an optical pulse train with a repetition rate of 16.7 MHz and pulse width of 0.37 ps. This is a simple, low-cost, stable, and convenient laser oscillator for applications where eye-safe and low-photon-energy light sources are required, such as sensing and biomedical diagnostics.
    Matched MeSH terms: Equipment Design
  5. Zaman MR, Islam MT, Misran N, Yatim B
    ScientificWorldJournal, 2014;2014:831435.
    PMID: 24977230 DOI: 10.1155/2014/831435
    A radio frequency (RF) resonator using glass-reinforced epoxy material for C and X band is proposed in this paper. Microstrip line technology for RF over glass-reinforced epoxy material is analyzed. Coupling mechanism over RF material and parasitic coupling performance is explained utilizing even and odd mode impedance with relevant equivalent circuit. Babinet's principle is deployed to explicate the circular slot ground plane of the proposed resonator. The resonator is designed over four materials from different backgrounds which are glass-reinforced epoxy, polyester, gallium arsenide (GaAs), and rogers RO 4350B. Parametric studies and optimization algorithm are applied over the geometry of the microstrip resonator to achieve dual band response for C and X band. Resonator behaviors for different materials are concluded and compared for the same structure. The final design is fabricated over glass-reinforced epoxy material. The fabricated resonator shows a maximum directivity of 5.65 dBi and 6.62 dBi at 5.84 GHz and 8.16 GHz, respectively. The lowest resonance response is less than -20 dB for C band and -34 dB for X band. The resonator is prototyped using LPKF (S63) drilling machine to study the material behavior.
    Matched MeSH terms: Equipment Design
  6. Zaman MR, Islam MT, Misran N, Mandeep JS
    ScientificWorldJournal, 2014;2014:131374.
    PMID: 24895643 DOI: 10.1155/2014/131374
    Analysis of the resonance response improvement of a planar C-band (4-8 GHz) antenna is proposed using parasitic element method. This parasitic element based method is validated for change in the active and parasitic antenna elements. A novel dual-band antenna for C-band application covering 5.7 GHz and 7.6 GHz is designed and fabricated. The antenna is composed of circular parasitic element with unequal microstrip lines at both sides and a rectangular partial ground plane. A fractional bandwidth of 13.5% has been achieved from 5.5 GHz to 6.3 GHz (WLAN band) for the lower band. The upper band covers from 7.1 GHz to 8 GHz with a fractional bandwidth of 12%. A gain of 6.4 dBi is achieved at the lower frequency and 4 dBi is achieved at the upper frequency. The VSWR of the antenna is less than 2 at the resonance frequency.
    Matched MeSH terms: Equipment Design
  7. Zakaria NZ, Masnan MJ, Zakaria A, Shakaff AY
    Sensors (Basel), 2014;14(7):12233-55.
    PMID: 25010697 DOI: 10.3390/s140712233
    Herbal-based products are becoming a widespread production trend among manufacturers for the domestic and international markets. As the production increases to meet the market demand, it is very crucial for the manufacturer to ensure that their products have met specific criteria and fulfil the intended quality determined by the quality controller. One famous herbal-based product is herbal tea. This paper investigates bio-inspired flavour assessments in a data fusion framework involving an e-nose and e-tongue. The objectives are to attain good classification of different types and brands of herbal tea, classification of different flavour masking effects and finally classification of different concentrations of herbal tea. Two data fusion levels were employed in this research, low level data fusion and intermediate level data fusion. Four classification approaches; LDA, SVM, KNN and PNN were examined in search of the best classifier to achieve the research objectives. In order to evaluate the classifiers' performance, an error estimator based on k-fold cross validation and leave-one-out were applied. Classification based on GC-MS TIC data was also included as a comparison to the classification performance using fusion approaches. Generally, KNN outperformed the other classification techniques for the three flavour assessments in the low level data fusion and intermediate level data fusion. However, the classification results based on GC-MS TIC data are varied.
    Matched MeSH terms: Equipment Design
  8. Zainudin M, Razak M, Shukur SH
    Med J Malaysia, 2000 Sep;55 Suppl C:59-67.
    PMID: 11200046
    We present the results of our experience in treating comminuted tibial shaft fractures with reamed interlocking intramedullary nail from September 1993 to December 1995. In this retrospective study, there were fifty patients with an average follow-up of 14.3 months (range six to twenty-eight months). Ninety-eight percent of the fractures were due to motor-vehicle accident with majority of the patients being motorcyclist (96%). Thirty-eight fractures were closed and twelve were open (Gustilo grade I--8; grade II--4); 44% of them had additional fractures or other injuries. According to Winquist-Hansen classification of diaphyseal fracture comminution, there were 24% type I; 18% type II; 26% type III and 32% type IV. The union rate was 98%. There were 6 infections, 2 superficial and 4 deep. All these infections arose from closed fractures, which was possibly due to the long operative time. No patients with open fractures, which underwent delayed nailing, had infection. One of the patient had severe deep infection which required early nail removal before union. Anterior knee pain following nailing occurred in 6% of the patients. The average hospital stay after operation was 3.4 days. Ninety-four percent of the patients had excellent to good functional outcome after nailing. The mean time to regain full range of movement of knee and ankle was 8.4 weeks. Patients were allowed full weight bearing in the average time of 10.7 weeks and the mean time to return to work was 24.7 weeks.
    Matched MeSH terms: Equipment Design
  9. Zainal-Mokhtar K, Mohamad-Saleh J
    Sensors (Basel), 2013;13(9):11385-406.
    PMID: 24064598 DOI: 10.3390/s130911385
    This paper presents novel research on the development of a generic intelligent oil fraction sensor based on Electrical Capacitance Tomography (ECT) data. An artificial Neural Network (ANN) has been employed as the intelligent system to sense and estimate oil fractions from the cross-sections of two-component flows comprising oil and gas in a pipeline. Previous works only focused on estimating the oil fraction in the pipeline based on fixed ECT sensor parameters. With fixed ECT design sensors, an oil fraction neural sensor can be trained to deal with ECT data based on the particular sensor parameters, hence the neural sensor is not generic. This work focuses on development of a generic neural oil fraction sensor based on training a Multi-Layer Perceptron (MLP) ANN with various ECT sensor parameters. On average, the proposed oil fraction neural sensor has shown to be able to give a mean absolute error of 3.05% for various ECT sensor sizes.
    Matched MeSH terms: Equipment Design
  10. Zainal MA, Ahmad A, Mohamed Ali MS
    Biomed Microdevices, 2017 Mar;19(1):8.
    PMID: 28124762 DOI: 10.1007/s10544-017-0148-5
    This paper reports the wireless Shape-Memory-Polymer actuator operated by external radio frequency magnetic fields and its application in a drug delivery device. The actuator is driven by a frequency-sensitive wireless resonant heater which is bonded directly to the Shape-Memory-Polymer and is activated only when the field frequency is tuned to the resonant frequency of heater. The heater is fabricated using a double-sided Cu-clad Polyimide with much simpler fabrication steps compared to previously reported methods. The actuation range of 140 μm as the tip opening distance is achieved at device temperature 44 °C in 30 s using 0.05 W RF power. A repeatability test shows that the actuator's average maximum displacement is 110 μm and standard deviation of 12 μm. An experiment is conducted to demonstrate drug release with 5 μL of an acidic solution loaded in the reservoir and the device is immersed in DI water. The actuator is successfully operated in water through wireless activation. The acidic solution is released and diffused in water with an average release rate of 0.172 μL/min.
    Matched MeSH terms: Equipment Design
  11. Yusoff N, Abu Osman NA, Pingguan-Murphy B
    Med Eng Phys, 2011 Jul;33(6):782-8.
    PMID: 21356602 DOI: 10.1016/j.medengphy.2011.01.013
    A mechanical-conditioning bioreactor has been developed to provide bi-axial loading to three-dimensional (3D) tissue constructs within a highly controlled environment. The computer-controlled bioreactor is capable of applying axial compressive and shear deformations, individually or simultaneously at various regimes of strain and frequency. The reliability and reproducibility of the system were verified through validation of the spatial and temporal accuracy of platen movement, which was maintained over the operating length of the system. In the presence of actual specimens, the system was verified to be able to deliver precise bi-axial load to the specimens, in which the deformation of every specimen was observed to be relatively homogeneous. The primary use of the bioreactor is in the culture of chondrocytes seeded within an agarose hydrogel while subjected to physiological compressive and shear deformation. The system has been designed specifically to permit the repeatable quantification and characterisation of the biosynthetic activity of cells in response to a wide range of short and long term multi-dimensional loading regimes.
    Matched MeSH terms: Equipment Design
  12. Yusof MI, Yusof AH, Abdullah MS, Hussin TM
    J Orthop Surg (Hong Kong), 2007 Apr;15(1):67-72.
    PMID: 17429121
    To measure the diameter of the odontoid process in a Malaysian population using computed tomographic (CT) scan and determine the feasibility of treating type-II odontoid fractures using 2 cortical screws.
    Matched MeSH terms: Equipment Design
  13. Yu CY, Ang GY, Chan KG, Banga Singh KK, Chan YY
    Biosens Bioelectron, 2015 Aug 15;70:282-8.
    PMID: 25835520 DOI: 10.1016/j.bios.2015.03.048
    In this study, we developed a nucleic acid-sensing platform in which a simple, dry-reagent-based nucleic acid amplification assay is combined with a portable multiplex electrochemical genosensor. Preparation of an amplification reaction mix targeting multiple DNA regions of interest is greatly simplified because the lyophilized reagents need only be reconstituted with ultrapure water before the DNA sample is added. The presence of single or multiple target DNAs causes the corresponding single-stranded DNA (ssDNA) amplicons to be generated and tagged with a fluorescein label. The fluorescein-labeled ssDNA amplicons are then analyzed using capture probe-modified screen-printed gold electrode bisensors. Enzymatic amplification of the hybridization event is achieved through the catalytic production of electroactive α-naphthol by anti-fluorescein-conjugated alkaline phosphatase. The applicability of this platform as a diagnostic tool is demonstrated with the detection of toxigenic Vibrio cholerae serogroups O1 and O139, which are associated with cholera epidemics and pandemics. The platform showed excellent diagnostic sensitivity and specificity (100%) when challenged with 168 spiked stool samples. The limit of detection was low (10 colony-forming units/ml) for both toxigenic V. cholerae serogroups. A heat stability assay revealed that the dry-reagent amplification reaction mix was stable at temperatures of 4-56 °C, with an estimated shelf life of seven months. The findings of this study highlight the potential of combining a dry-reagent-based nucleic acid amplification assay with an electrochemical genosensor in a more convenient, sensitive, and sequence-specific detection strategy for multiple target nucleic acids.
    Matched MeSH terms: Equipment Design
  14. Yew KL, Anderson S, Farah R, Lim SH
    Asian Cardiovasc Thorac Ann, 2014 Oct;22(8):979-80.
    PMID: 24887840 DOI: 10.1177/0218492313491583
    Central vein stenosis is not uncommon in hemodialysis-dependent patients as a result of mechanical damage to the vessel walls from prior cannulation. It can cause ipsilateral upper limb swelling and pain, resulting in suboptimal hemodialysis. It is unfortunate for bilateral central vein stenosis to develop concomitantly, and rare in the setting of an in-situ pacemaker. This case illustrates the successful ligation of a nondependent left arteriovenous fistula and stenting of the right subclavian vein with functioning ipsilateral arteriovenous fistula, to overcome the problem of symptomatic bilateral upper limb swelling.
    Matched MeSH terms: Equipment Design
  15. Yee R, Gadler F, Hussin A, Bin Omar R, Khaykin Y, Verma A, et al.
    Heart Rhythm, 2014 Jul;11(7):1150-5.
    PMID: 24801899 DOI: 10.1016/j.hrthm.2014.04.020
    Left ventricular (LV) lead implantation for cardiac resynchronization therapy (CRT) is associated with lead dislodgement rates ranging from 3% to 10%, and some implant approaches to prevent dislodgement may contribute to suboptimal CRT response. We report our early human experience with an LV lead with a side helix for active fixation to the coronary vein wall.
    Matched MeSH terms: Equipment Design
  16. Yang Y, Wei X, Zhang N, Zheng J, Chen X, Wen Q, et al.
    Nat Commun, 2021 08 12;12(1):4876.
    PMID: 34385436 DOI: 10.1038/s41467-021-25075-8
    While the printed circuit board (PCB) has been widely considered as the building block of integrated electronics, the world is switching to pursue new ways of merging integrated electronic circuits with textiles to create flexible and wearable devices. Herein, as an alternative for PCB, we described a non-printed integrated-circuit textile (NIT) for biomedical and theranostic application via a weaving method. All the devices are built as fibers or interlaced nodes and woven into a deformable textile integrated circuit. Built on an electrochemical gating principle, the fiber-woven-type transistors exhibit superior bending or stretching robustness, and were woven as a textile logical computing module to distinguish different emergencies. A fiber-type sweat sensor was woven with strain and light sensors fibers for simultaneously monitoring body health and the environment. With a photo-rechargeable energy textile based on a detailed power consumption analysis, the woven circuit textile is completely self-powered and capable of both wireless biomedical monitoring and early warning. The NIT could be used as a 24/7 private AI "nurse" for routine healthcare, diabetes monitoring, or emergencies such as hypoglycemia, metabolic alkalosis, and even COVID-19 patient care, a potential future on-body AI hardware and possibly a forerunner to fabric-like computers.
    Matched MeSH terms: Equipment Design
  17. Yang T, Xiao Y, Zhang Z, Liang Y, Li G, Zhang M, et al.
    Sci Rep, 2018 09 28;8(1):14518.
    PMID: 30266999 DOI: 10.1038/s41598-018-32757-9
    Soft robots driven by stimuli-responsive materials have their own unique advantages over traditional rigid robots such as large actuation, light weight, good flexibility and biocompatibility. However, the large actuation of soft robots inherently co-exists with difficulty in control with high precision. This article presents a soft artificial muscle driven robot mimicking cuttlefish with a fully integrated on-board system including power supply and wireless communication system. Without any motors, the movements of the cuttlefish robot are solely actuated by dielectric elastomer which exhibits muscle-like properties including large deformation and high energy density. Reinforcement learning is used to optimize the control strategy of the cuttlefish robot instead of manual adjustment. From scratch, the swimming speed of the robot is enhanced by 91% with reinforcement learning, reaching to 21 mm/s (0.38 body length per second). The design principle behind the structure and the control of the robot can be potentially useful in guiding device designs for demanding applications such as flexible devices and soft robots.
    Matched MeSH terms: Equipment Design
  18. 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
  19. Yakub F, Md Khudzari AZ, Mori Y
    Int J Rehabil Res, 2014 Mar;37(1):9-21.
    PMID: 24126254 DOI: 10.1097/MRR.0000000000000035
    This paper presents and studies various selected literature primarily from conference proceedings, journals and clinical tests of the robotic, mechatronics, neurology and biomedical engineering of rehabilitation robotic systems. The present paper focuses of three main categories: types of rehabilitation robots, key technologies with current issues and future challenges. Literature on fundamental research with some examples from commercialized robots and new robot development projects related to rehabilitation are introduced. Most of the commercialized robots presented in this paper are well known especially to robotics engineers and scholars in the robotic field, but are less known to humanities scholars. The field of rehabilitation robot research is expanding; in light of this, some of the current issues and future challenges in rehabilitation robot engineering are recalled, examined and clarified with future directions. This paper is concluded with some recommendations with respect to rehabilitation robots.
    Matched MeSH terms: Equipment Design
  20. Yahaya Rashid AS, Ramli R, Mohamed Haris S, Alias A
    ScientificWorldJournal, 2014;2014:190214.
    PMID: 25101312 DOI: 10.1155/2014/190214
    The dynamic behavior of a body-in-white (BIW) structure has significant influence on the noise, vibration, and harshness (NVH) and crashworthiness of a car. Therefore, by improving the dynamic characteristics of BIW, problems and failures associated with resonance and fatigue can be prevented. The design objectives attempt to improve the existing torsion and bending modes by using structural optimization subjected to dynamic load without compromising other factors such as mass and stiffness of the structure. The natural frequency of the design was modified by identifying and reinforcing the structure at critical locations. These crucial points are first identified by topology optimization using mass and natural frequencies as the design variables. The individual components obtained from the analysis go through a size optimization step to find their target thickness of the structure. The thickness of affected regions of the components will be modified according to the analysis. The results of both optimization steps suggest several design modifications to achieve the target vibration specifications without compromising the stiffness of the structure. A method of combining both optimization approaches is proposed to improve the design modification process.
    Matched MeSH terms: Equipment Design
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