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Fulltext Simulation of EMP generator using MATLAB

Betantya Nugroho, Azli Yahya, Nor Hisham, Kamal Khalil, Abd. Rahim, Mohd Najeb Jamaluddin

Journal of Advanced Research Design, 2018;44(1):1-6.
MyJurnal

Electromagnetic pulse (EMP) is a sudden burst of wide-band, high-intensity electromagnetic radiation. EMP also called as a transient electromagnetic disturbance, a short burst of electromagnetic energy. Effect of EMP to automobile is classify as medium threats to vehicle attacks where EMP aims at damaging electronic devices such as on board sensors and processors, CPU which found in almost all models from 1990’s and forward. This paper presents a MATLAB simulation of EMP generator by means of Switch Mode Power Supply, thus the electrical shielding can be studied further. Theoretically, EMP generator is developed by implementing energy storage circuit and discharge control circuit. Sending a rapidly changing electrical current through a loop will create an electromagnetic field in the form of a pulse. The results show an increase in pulse voltage from 12 VDC to 758 VDC with a current of 1500 A. A MATLAB model on the coverage area affected by EMP pulse will be developed in the next phase of the research.
Fulltext Design of Helical Capacitance Sensor for Holdup Measurement in Two-Phase Stratified Flow: A Sinusoidal Function Approach

Lim LG, Pao WK, Hamid NH, Tang TB

Sensors (Basel), 2016 Jul 04;16(7).
PMID: 27384567 DOI: 10.3390/s16071032

A 360° twisted helical capacitance sensor was developed for holdup measurement in horizontal two-phase stratified flow. Instead of suppressing nonlinear response, the sensor was optimized in such a way that a 'sine-like' function was displayed on top of the linear function. This concept of design had been implemented and verified in both software and hardware. A good agreement was achieved between the finite element model of proposed design and the approximation model (pure sinusoidal function), with a maximum difference of ±1.2%. In addition, the design parameters of the sensor were analysed and investigated. It was found that the error in symmetry of the sinusoidal function could be minimized by adjusting the pitch of helix. The experiments of air-water and oil-water stratified flows were carried out and validated the sinusoidal relationship with a maximum difference of ±1.2% and ±1.3% for the range of water holdup from 0.15 to 0.85. The proposed design concept therefore may pose a promising alternative for the optimization of capacitance sensor design.
Fulltext Advances in Testing Techniques for Digital Microfluidic Biochips

Shukla V, Hussin FA, Hamid NH, Zain Ali NB

Sensors (Basel), 2017 Jul 27;17(8).
PMID: 28749411 DOI: 10.3390/s17081719

With the advancement of digital microfluidics technology, applications such as on-chip DNA analysis, point of care diagnosis and automated drug discovery are common nowadays. The use of Digital Microfluidics Biochips (DMFBs) in disease assessment and recognition of target molecules had become popular during the past few years. The reliability of these DMFBs is crucial when they are used in various medical applications. Errors found in these biochips are mainly due to the defects developed during droplet manipulation, chip degradation and inaccuracies in the bio-assay experiments. The recently proposed Micro-electrode-dot Array (MEDA)-based DMFBs involve both fluidic and electronic domains in the micro-electrode cell. Thus, the testing techniques for these biochips should be revised in order to ensure proper functionality. This paper describes recent advances in the testing technologies for digital microfluidics biochips, which would serve as a useful platform for developing revised/new testing techniques for MEDA-based biochips. Therefore, the relevancy of these techniques with respect to testing of MEDA-based biochips is analyzed in order to exploit the full potential of these biochips.
Fulltext Droplet Velocity Measurement Based on Dielectric Layer Thickness Variation Using Digital Microfluidic Devices

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.
Primary stability of self-tapping dual etched implants

Kassim ZH, Nor Hisham ND, Dardiri NA, Goot Heah K, Hazwani Baharuddin I, De Angelis N

Minerva Stomatol, 2019 Dec;68(6):291-296.
PMID: 32052617 DOI: 10.23736/S0026-4970.19.04242-0

BACKGROUND: The aims of this study were to enumerate the primary implant stability quotient (ISQ) value of self-tapping dual etched implants and to explore the influence of parameters such as implant length, implant diameter, age, gender, implant location and osteotomy preparation on the ISQ value.
METHODS: Retrospective data from clinical worksheets given to participants during two implant courses held between the periods of 2013 to 2014 were evaluated. A total of 61 implants were considered based on the inclusion criteria. The effects of parameters such as implant diameter, implant length, age, gender, implant location and osteotomy protocol on ISQ values were analyzed.
RESULTS: Mean ISQ value for all implants was 67.21±9.13. Age of patients (P=0.016) and location of implants (P=0.041) had a significant linear relationship with the ISQ values. Within the age limit of the patients in this study, it was found that an increase in one year of patient's age results in 0.20 decrease in ISQ value (95% CI: -0.36, -0.04). However, placing an implant in the posterior maxilla may negatively affect the ISQ with a likely decrease in primary stability by 6.76 ISQ value (95% CI: -13.22, -0.30).
CONCLUSIONS: The results suggest that the mean ISQ achieved by the participants were comparable with the range reported for this particular type of implants. The patient's age and location of implants were elucidated as the determinant factors of primary implant stability.
Fulltext Optical Characterization of Lorentz Force Based CMOS-MEMS Magnetic Field Sensor

Dennis JO, Ahmad F, Khir MH, Bin Hamid NH

Sensors (Basel), 2015;15(8):18256-69.
PMID: 26225972 DOI: 10.3390/s150818256

Magnetic field sensors are becoming an essential part of everyday life due to the improvements in their sensitivities and resolutions, while at the same time they have become compact, smaller in size and economical. In the work presented herein a Lorentz force based CMOS-MEMS magnetic field sensor is designed, fabricated and optically characterized. The sensor is fabricated by using CMOS thin layers and dry post micromachining is used to release the device structure and finally the sensor chip is packaged in DIP. The sensor consists of a shuttle which is designed to resonate in the lateral direction (first mode of resonance). In the presence of an external magnetic field, the Lorentz force actuates the shuttle in the lateral direction and the amplitude of resonance is measured using an optical method. The differential change in the amplitude of the resonating shuttle shows the strength of the external magnetic field. The resonance frequency of the shuttle is determined to be 8164 Hz experimentally and from the resonance curve, the quality factor and damping ratio are obtained. In an open environment, the quality factor and damping ratio are found to be 51.34 and 0.00973 respectively. The sensitivity of the sensor is determined in static mode to be 0.034 µm/mT when a current of 10 mA passes through the shuttle, while it is found to be higher at resonance with a value of 1.35 µm/mT at 8 mA current. Finally, the resolution of the sensor is found to be 370.37 µT.
Early visual analysis tool using magnetoencephalography for treatment and recovery of neuronal dysfunction

Rasheed W, Neoh YY, Bin Hamid NH, Reza F, Idris Z, Tang TB

Comput Biol Med, 2017 10 01;89:573-583.
PMID: 28551109 DOI: 10.1016/j.compbiomed.2017.05.005

Functional neuroimaging modalities play an important role in deciding the diagnosis and course of treatment of neuronal dysfunction and degeneration. This article presents an analytical tool with visualization by exploiting the strengths of the MEG (magnetoencephalographic) neuroimaging technique. The tool automates MEG data import (in tSSS format), channel information extraction, time/frequency decomposition, and circular graph visualization (connectogram) for simple result inspection. For advanced users, the tool also provides magnitude squared coherence (MSC) values allowing personalized threshold levels, and the computation of default model from MEG data of control population. Default model obtained from healthy population data serves as a useful benchmark to diagnose and monitor neuronal recovery during treatment. The proposed tool further provides optional labels with international 10-10 system nomenclature in order to facilitate comparison studies with EEG (electroencephalography) sensor space. Potential applications in epilepsy and traumatic brain injury studies are also discussed.
Firefighter satisfaction and happiness at work: how big is the effect?

Muthukumaran M, Mohd Nadzrul Safiq AR, Rosnah I, Nor Hisham M, Ashrul Riezal A, Ismail AG

Med J Malaysia, 2023 May;78(3):287-295.
PMID: 37271837

INTRODUCTION: Firefighter satisfaction plays a crucial role in overall workplace happiness. We seek to quantify the effect size of firefighters' satisfaction with happiness at work after adjusting for socio-demographic attributes.
MATERIALS AND METHODS: This study used data from an online cross-sectional survey that was conducted from 24 June to 24 July 2021 in the Fire and Rescue Department of Malaysia. Firefighters were approached using the saturation sampling technique. They received online surveys via email through the Director of State and follow-up reminders through the Assistant Director of State Operations. A total of two filter questionnaires were employed i.e. type and duration of service. Firefighters stating that they were volunteer/auxiliary firefighters or had been in service for 2 years or less were excluded. In this study, data from 6041 out of 8581 firefighters were included for further analysis. The survey utilised the validated staff satisfaction index (SSI) and the happy career (HC) scale for in-service firefighters. SSI was a dual-dimension index consisting of welfare and protection against hazards at work, with 16 subdimensions. The HC is a five multi-dimensional items scale. Then, we used multiple linear regression to obtain the coefficient of determination while adjusting for age groups, gender, marital status, job grade, years of service and region of service.
RESULTS: A total of 6041 eligible data points were analysed in the study. The mean (±SD) age was 38.70 (8.97) years, of which 95.9% were male. The firefighters were in service for a median of 14 years (Q1, Q3: 8, 21). The firefighter reported higher life satisfaction (mean [SD] = 78.30 [9.15]) than happiness at work (mean [SD] = 77.22 [0.20]). The mean happiness scores differed significantly between years of service groups (p<0.001), region of service (p<0.001), marital status (p=0.029) and grade (p<0.001). Firefighters' satisfaction contributed 42.7% of workplace happiness (βadj=1.096 [95% CI: 1.064, 1.128]; p<0.001) after adjusting for frontline, married, the central region of service and male gender as control variables.
CONCLUSION: Firefighter satisfaction had a large effect size on happiness at work (42.7%). However, the interpretation of this effect size should be done with caution because happiness at work is inseparable from other life dimensions such as stability in matrimonial relationships and finances, involvement in leisure and religious activities and being mentally healthy.
Fulltext Towards Multiplex Molecular Diagnosis-A Review of Microfluidic Genomics Technologies

Basha IHK, Ho ETW, Yousuff CM, Hamid NHB

Micromachines (Basel), 2017 Aug 30;8(9).
PMID: 30400456 DOI: 10.3390/mi8090266

Highly sensitive and specific pathogen diagnosis is essential for correct and timely treatment of infectious diseases, especially virulent strains, in people. Point-of-care pathogen diagnosis can be a tremendous help in managing disease outbreaks as well as in routine healthcare settings. Infectious pathogens can be identified with high specificity using molecular methods. A plethora of microfluidic innovations in recent years have now made it increasingly feasible to develop portable, robust, accurate, and sensitive genomic diagnostic devices for deployment at the point of care. However, improving processing time, multiplexed detection, sensitivity and limit of detection, specificity, and ease of deployment in resource-limited settings are ongoing challenges. This review outlines recent techniques in microfluidic genomic diagnosis and devices with a focus on integrating them into a lab on a chip that will lead towards the development of multiplexed point-of-care devices of high sensitivity and specificity.
Fulltext Identification of novel large genomic rearrangements at the BRCA1 locus in Malaysian women with breast cancer

Sharifah NA, Nurismah MI, Lee HC, Aisyah AN, Clarence-Ko CH, Naqiyah I, et al.

Cancer Epidemiol, 2010 Aug;34(4):442-7.
PMID: 20451485 DOI: 10.1016/j.canep.2010.04.010

The incidence of breast cancer has been on the rise in Malaysia. It is suggested that a subset of breast cancer cases were associated with germline mutation in breast cancer susceptibility (BRCA) genes. Most of the BRCA mutations reported in Malaysia were point mutations, small deletions and insertions. Here we report the first study of BRCA large genomic rearrangements (LGRs) in Malaysia. We aimed to detect the presence of LGRs in the BRCA genes of Malaysian patients with breast cancer.
Adaptation of coastal defence structure as a mechanism to alleviate coastal erosion in monsoon dominated coast of Peninsular Malaysia

Dong WS, Ariffin EH, Saengsupavanich C, Mohd Rashid MA, Mohd Shukri MH, Ramli MZ, et al.

J Environ Manage, 2023 May 01;333:117391.
PMID: 36774836 DOI: 10.1016/j.jenvman.2023.117391

The complexity of the coastal environment and the advent of climate change cause coastal erosion, which is incontrovertibly a significant concern worldwide, including Peninsular Malaysia, where, the coast is threatened by severe erosion linked to anthropogenic factors and monsoonal wind-driven waves. Consequently, the Malaysian government implemented a mitigation plan using several coastal defence systems to overcome the coastal erosion problem. This study assesses coastal erosion management strategies along a monsoon-dominated coasts by evaluating the efficacy of coastal protection structures against the coast. To this end, we analysed 244 km of the coastline of Terengganu, a federal state located on the east coast of Peninsular Malaysia. Due to a higher frequency of storms and the ensuing inception of high wave energy environments during the northeast monsoon (relative to southwest monsoon), the study area is the most impacted region in Malaysia with regard to coastal erosion. Fifty-five (55) coastal defence structures were detected along the Terengganu coastline. The Digital Shoreline Analysis System (DSAS) was utilised to compute changes in the rate statistics for various historical shoreline positions along the Terengganu coast to assess the efficacy of the defence structures. Additionally, this study acquired the perception of the existing coastal management strategies through an interview session with the concerned stakeholders. The rate statistics revealed the effectiveness and impact of the coastal defence structure on the coastline. Assessing the functionality of the coastal defence structures shed light on the present scenario of coastal erosion management. Greater efficacy and lower impact of coastal defence structures are prescribed for coastal erosion management strategies across the monsoon-dominated coast.

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