Browse publications by year: 2017

Fulltext Structured lifestyle intervention based on a trans-cultural diabetes-specific nutrition algorithm (tDNA) in individuals with type 2 diabetes: a randomized controlled trial

Chee WSS, Gilcharan Singh HK, Hamdy O, Mechanick JI, Lee VKM, Barua A, et al.

BMJ Open Diabetes Res Care, 2017;5(1):e000384.
PMID: 29435347 DOI: 10.1136/bmjdrc-2016-000384

OBJECTIVE: Trans-cultural diabetes nutrition algorithm (tDNA) was created by international task force and culturally customized for Malaysian population. This study was designed to evaluate its effectiveness versus usual diabetes care in primary care settings.
RESEARCH DESIGN AND METHODS: We randomized 230 patients with overweight/obesity, type 2 diabetes, and glycated hemoglobin (A1c) 7%-11% to receive usual care (UC) or UC with tDNA for 6 months. The tDNA intervention consisted of structured low-calorie meal plan, diabetes-specific meal replacements, and increased physical activity. Participants were counseled either through motivational interviewing (tDNA-MI) or conventional counseling (tDNA-CC). The UC group received standard dietary and exercise advice through conventional counseling. All patients were followed for another 6 months after intervention.
RESULTS: At 6 months, A1c decreased significantly in tDNA-MI (-1.1±0.1%, p<0.001) and tDNA-CC (-0.5±0.1%, p=0.001) but not in UC (-0.2±0.1%, p=NS). Body weight decreased significantly in tDNA-MI (-6.9±1.3 kg, p<0.001) and tDNA-CC (-5.3±1.2 kg, p<0.001) but not in UC (-0.8±0.5 kg, p=NS). tDNA-MI patients had significantly lower fasting plasma glucose (tDNA-MI: -1.1±0.3 mmol/L, p<0.001; tDNA-CC: -0.6±0.3 mmol/L, p=NS; UC: 0.1±0.3 mmol/L, p=NS) and systolic blood pressure (tDNA-MI: -9±2 mm Hg, p<0.001; tDNA-CC: -9±2 mm Hg, p=0.001; UC: -1±2 mm Hg, p=NS). At 1 year, tDNA-MI patients maintained significant reduction in A1c (tDNA-MI: -0.5±0.2%, p=0.006 vs tDNA-CC: 0.1±0.2%, p=NS and UC: 0.02±0.01%, p=NS) and significant weight loss (tDNA-MI: -5.8±1.3 kg, p<0.001 vs tDNA-CC: -3.3±1.2 kg, p=NS and UC: 0.5±0.6 kg, p=NS).
CONCLUSIONS: Structured lifestyle intervention through culturally adapted nutrition algorithm and motivational interviewing significantly improved diabetes control and body weight in primary care setting.
Fulltext Development and evaluation of exemestane-loaded lyotropic liquid crystalline gel formulations

Musa MN, David SR, Zulkipli IN, Mahadi AH, Chakravarthi S, Rajabalaya R

Bioimpacts, 2017;7(4):227-239.
PMID: 29435430 DOI: 10.15171/bi.2017.27

Introduction:

The use of liquid crystalline (LC) gel formulations for drug delivery has considerably improved the current delivery methods in terms of bioavailability and efficacy. The purpose of this study was to develop and evaluate LC gel formulations to deliver the anti-cancer drug exemestane through transdermal route.
Methods:
Two LC gel formulations were prepared by phase separation coacervation method using glyceryl monooleate (GMO), Tween 80 and Pluronic® F127 (F127). The formulations were characterized with regard to encapsulation efficiency (EE), vesicle size, Fourier transform infrared (FTIR) spectroscopy, surface morphology (using light and fluorescence microscopy), in vitro release, ex vivo permeation, in vitro effectiveness test on MDA-MB231 cancer cell lines and histopathological analysis.
Results:
Results exhibited that the EE was 85%-92%, vesicle size was 119.9-466.2 nm while morphology showed spherical vesicles after hydration. An FTIR result also revealed that there was no significant shift in peaks corresponding to Exemestane and excipients. LC formulations release the drug from cellulose acetate and Strat-MTM membrane from 15%-88.95%, whereas ex vivo permeation ranges from 37.09-63%. The in vitro effectiveness study indicated that even at low exemestane concentrations (12.5 and 25 μg/mL) the formulations were able to induce cancer cell death, regardless of the surfactant used. Histopathological analysis thinning of the epidermis as the formulations penetrate into the intercellular regions of squamous cells.
Conclusion:
The results conjectured that exemestane could be incorporated into LC gels for the transdermal delivery system and further preclinical studies such as pharmacokinetic and pharmacodynamic studies will be carried out with suitable animal models.
Fulltext Optimising PID controller using slope variation method for positioning radio telescope

Mohamad Zaber, N., Ishak, A.J., Che Soh, A., Hasan, M.K., Ishak, A.N.

Pertanika Journal of Science & Technology, 2017;25(101):275-284.
MyJurnal

Radio telescope is an application that requires a precise position control as it should point to the exact
coordinate so that it could receive the desired signal. The main idea of this paper is to optimise the PID
controller by introducing slope variation method in order to control the position of a radio telescope.
This proposed method is also validated with the presence of disturbance, such as wind gust disturbance
with different speed amplitude. The results indicate that the proposed optimisation method has a better
result with no overshoot and able to attenuate wind gust disturbance when compared with conventional
PID controller.
Fulltext Planar sensors array for water contaminants detections

Aizat Azmi, Sallehuddin Ibrahim, Ahmad Amsyar Azman, Mohd Amri Md Yunus

Pertanika Journal of Science & Technology, 2017;25(101):267-274.
MyJurnal

Planar electromagnetic sensors are widely used in many applications due to its low cost, simple
architecture, and fast response. Currently, there are many types of membranes which have been introduced
to remove contaminants from an aqueous solution. Hence, the water quality could be maintained and
safe to consume. The objective of this paper is to apply and investigate the effectiveness of a selective
membrane in detecting nitrate, phosphate, zinc, and nickel ions by means of planar electromagnetic
sensors array (PESA). The samples have four different concentration levels, 5 ppm, 25 ppm, 75 ppm,
and 100 ppm. The selective membrane’s performance is evaluated based on absolute average sensitivity
(|Z%|). This performance is compared with conventional coating such as incralac. The developed
membrane consists of two elements which are polymer and solvent. Modified silica is selected as a
polymer material while N-(2-Aminoethyl)-3 Aminipropyltrimethoxysilane is selected as a solvent. The
selection of these materials is based on their ability to attract the contaminants in the aqueous solution
and hence increased the selectivity. The proposed sensor with a membrane shows its higher sensitivity
compared to incralac. The highest sensitivity is 338 % which observed in the presence of membrane
for the nickel detection. Meanwhile, the lowest sensitivity using membrane is 12 % for zinc detection.
Fulltext An integrated system wide reactive power management strategy for transmission and distribution system based on techno economic analysis

Jun, Huat Tang, Asnawi Mohd Busrah, Mohd Hafiz Mat Daud, Khairuddin Abdullah, Mau, TengAu, Lau, Chee Chong

Pertanika Journal of Science & Technology, 2017;25(101):19-24.
MyJurnal

This paper presents a methodology to determine the economic power factor at the point of power transfer
between transmission and distribution (T & D) system for a vertically integrated utility company. An
integrated reactive power management strategy is developed to optimize the planting up of reactive power
compensation devices in the transmission and distribution system. The transmission and distribution
network is modelled and simulated using commercially available software to analyse the transmission
network losses, capacity released and voltage stability due to capacitor plant up. Economic analysis on
the total cost of ownership of capacitor banks is used to determine the economic benefits of technical
losses reduction and capacity. released in transmission and distribution equipment through the planting
up of capacitor bank. The proposed methodology can be used by a vertically integrated power utility
where a single utility own both the transmission and distribution system. A software base data analytic,
power system automation and economic analysis tool was developed to facilitate the planning engineer
in reactive power planning and management.
Fulltext A study of negative bias temperature instability (NBTI) in p-MOSFET devices

Hussin, H., Zainudin, M.F.

Pertanika Journal of Science & Technology, 2017;25(101):257-266.
MyJurnal

Negative bias temperature instability (NBTI) is a common phenomenon in a p-channel MOSFET device
under a negative gate-to-source voltage at a high stress temperature. This paper presents the NBTI
characterisation based on different analysis methods and stress conditions on p-MOSFET devices. The
atomic hydrogen concentration is probed at interface, Poly-Si and channel of p-MOSFET under study
using SILVACO TCAD tool. In addition, the behaviour of the permanent and recoverable component
was investigated based on AC stress at different stress conditions using Modelling Interface Generation
(MIG) tool. The results show that increases in temperature, negative voltage stress gate and decreases
in frequency increase the threshold voltage shift, thus enhancing NBTI degradation.
Fulltext Synchronous reference frame fundamental method in shunt active power filter for mitigation of current harmonics

Musa, S., Radzi, M.A.M.

Pertanika Journal of Science & Technology, 2017;25(101):249-256.
MyJurnal

This research presents compensation of current harmonic disturbance in power system network using
shunt active power filter. In this paper, harmonic extraction using Synchronous Reference Frame
Fundamental technique (SRFF) was investigated for three phase 3-wire system. It proposes a method
based on direct current measurement of load currents using a band pass filter at low cut off frequencies
to improve the filtering ability in highly contaminated loads. The proposed filter consists of second
order low pass and high pass filters cascaded together at suitable frequencies, estimated based on the
output of these units to mitigate the current harmonics. The performance of the system was simulated
in Matlab Platform and evaluated considering total harmonic distortion of the source current in a threephase
balanced network. The simulation results show the ability of the proposed tracking scheme to
accurately estimate harmonics.
Fulltext Method of determining load priority using fuzzy logic for adaptive under frequency load shedding technique

Isa, A.I.M., Dahlan, N.Y., Musirin, I., Naidu, K.

Pertanika Journal of Science & Technology, 2017;25(101):239-248.
MyJurnal

Power systems are usually exposed to numerous disturbances that can have an adverse effect on system
operation. Insufficient generation could lead to frequency declination and subsequently system collapse
in the absence of immediate control action. Frequency Load Shedding (UFLS) is a technique commonly
applied to overcome overloading and restore the system frequency. This paper presents an adaptive load
shedding approach to determine the best location with minimum amount of load to be shed. Load Ranking
Fuzzy Logic (LRFL) is used to rank the load based on their sensitivity and stability index. In order to
achieve this, the proposed strategy is verified using 11 kV Malaysian distributed network consisting of
different type of loads connected with single and multiple Distribution Generator (DG). The simulation
results show that the proposed strategy successfully stabilizes the system’s frequency.
Fulltext Application of evolutionary programming for the placement of TCSC and UPFC for minimisation of transmission losses and improvement of voltage profile

Nur Ashida Salim, Nabila Ismail, Muhammad Murtadha Othman

Pertanika Journal of Science & Technology, 2017;25(101):231-238.
MyJurnal

Flexible AC Transmission System (FACTS) devices are used in to improve stability and loadability of
transmission networks as well as minimise losses . Types of FACTS that are normally used are Thyristor
Controller Series Compensator (TCSC) and Unified Power Flow Controller (UPFC) which is to control
power flow and stability of the power system at a certain location. The TCSC is suitable because it can
be installed in a long transmission line system while UPFC can solve any reactive power problems.
The objective of this study is to minimise total power losses and to improve the voltage profile by using
FACTS devices in the transmission system. This paper proposes a static voltage stability index (SVSI)
to determine the size and placement of TCSC and the Evolutionary Programming (EP) technique. The
results of the transmission line losses and voltage profile using TCSC and UPFC are compared in order
to demonstrate which FACTS device can produce better results. The IEEE 14 bus system is used in this
study to validate the findings.
Fulltext FDTD computational simulation for SAR observation towards breast hyperthermia cancer procedure

Kasumawati Lias, Norlida Buniyamin

Pertanika Journal of Science & Technology, 2017;25(101):221-230.
MyJurnal

The radiation absorption distribution of electromagnetic energy into the breast phantom is of fundamental
importance in understanding its therapeutic capability emitted by the microstrip applicator for noninvasive
hyperthermia procedure. In this paper simple microstrip applicator with rectangular shape is
presented. Different operating frequency were investigated to observe radiation absorption distribution,
which is measured through specific absorption rate (SAR) parameter. The operational frequency was
915MHz and 2450MHz, the industry, scientific and medical (ISM) frequency range. As simulated by
using the finite difference time-domain (FDTD) computational simulation which is known as SEMCAD
X solver, the results shed an interesting observation on the SAR when frequency varies, which is shown
by the transformation onto the penetration depth and focusing capability onto the breast area to be treated.
Fulltext Seasonal variation of transmission line outages in peninsular Malaysia

Rawi, I. Mohamed, Ab-Kadir, M.Z.A., Izadi, M.

Pertanika Journal of Science & Technology, 2017;25(101):213-220.
MyJurnal

Researchers have observed the impact of climate changes on overhead line outages. It is known that
overhead lines are very prone to lightning strikes due to their height and location which are normally in
an open and exposed area. Studies have also reported that transmission and distribution lines experience
very high failure rates due to lightning strikes. The tropics experience greater lightning activities and
have higher peaks where transmission lines suffer frequent line outages. This paper examined studies
that have been conducted on line outages due to lightning activities, especially in the tropical areas.
Lightning detection system is also discussed as well as how to evaluate line performance. Seasonal
variation of lightning occurrences and line outage pattern help to predict lightning occurrences and to
optimise a suitable power protection system of overhead lines. It has been widely reported that lightning
occurrences and line outages are significantly related and lightning activity was more prevalent during
inter monsoon seasons.
Fulltext Effect of boron and oxygen doping to graphene band structure

Siti Fazlina Fauzi, Syarifah Norfaezah Sabki

Pertanika Journal of Science & Technology, 2017;25(101):205-212.
MyJurnal

Graphene band structure can be modulated when dopant atoms are introduced into graphene sheets. As
a result, there is flexibility in design and optimisation of electronic devices. In this study, the effects
of atomic doping to graphene band structure were investigated by using boron and oxygen as dopant
atoms. Different dopant concentrations and dopant locations in graphene sub lattices were studied by
using a 4x4 graphene sub lattice which consists of 32 carbon atoms. Results show that both dopants
cause opening of energy band gap of mono layer graphene. The highest energy band gap (Eg) value for
graphene doped with boron is 0.52 eV and the highest Eg value for graphene doped with oxygen is 1.67
eV, in which both results are obtained for highest dopant concentration and farthest dopant’s distance in a
graphene sheet. This shows that higher dopant concentration and farther dopant’s location in a graphene
sheet lead to higher energy band gap.
Fulltext Double series resonant dc-dc converter with uniform voltage stress on high voltage transformers

Nor Azura, Soib, Taib, Shahid, Iqbal

Pertanika Journal of Science & Technology, 2017;25(101):187-196.
MyJurnal

This paper proposes a novel double series resonant dc-dc converter with uniform voltage stress on a
transformer. It consists of a half-bridge inverter with two power switches (IGBTs), two series resonant
tank, two high-voltage transformers and a symmetrical voltage multiplier circuit. A symmetrical voltage
multiplier circuit is connected at the secondary side of the high voltage transformer to generate desired
high voltage dc output. Due to use of voltage multiplier circuit, the proposed converter requires smaller
turns ratio of the high voltage transformer, leading to reduction in size and volume of the transformer.
The proposed converter operates in discontinuous current mode by varying the switching frequency of
the converter. In a discontinuous current mode operation, all the power switches and output diodes of the
rectifier circuit turn-on and turn-off under zero current switching conditions. Therefore, it has features
of low switching losses and possibility of light-load operation. Besides, it costs less and is smaller in
size compared with conventional double series resonant dc-dc converter. It also has a simple operating
principle and suitable for high voltage and high power applications. Experimental results confirm the
proposed converter performs better than the others.
Fulltext Simulation of interleaved current fed full bridge converter for fuel cell electrical vehicle

Koay, Boon Kit, Nasrudin Abd Rahim, Siti Rohani Sheikh Raihan

Pertanika Journal of Science & Technology, 2017;25(101):179-186.
MyJurnal

Hydrogen fuel cell (HFC) is one of the renewable resources to address fossil fuel depletion and global
warming. Its primary advantages are power is generated from renewable fuel hydrogen and the emission
is only water. However, HFC supplies power in a slow dynamic response. In fuel cell electrical vehicle
(FCEV), energy storage system (ESS), i.e. supercapacitor and battery, is required to immediately
compensate the difference between load demand and power supply; the lifetime of HFC is affected
by current ripple. In order to manage power flow between HFC and load, HFC is interfaced with a
unidirectional DC-DC converter. The converter steps up the terminal fuel cell voltage and regulate the
voltage before it is connected to the load. Among the proposed HFC DC-DC converters, interleaved
DC-DC converter seems more suitable for FCEV application due to its advantages. When galvanic
isolation is required, current fed full bridge converter receives significant consideration as the module
of interleaved converter. This paper simulates interleaved current fed full bridge (ICFFB) converter and
discusses the suitability of ICFFB for FCEV application.
Fulltext A single-stage led driver with voltage doubler rectifier

Nurul Asikin, Shahid Iqbal, Mohamad Kamarol, Mohd Jamil

Pertanika Journal of Science & Technology, 2017;25(101):9-18.
MyJurnal

In this paper, a configuration of a single-stage AC-DC converter and a high voltage resonant controller
IC L6598 for LED street light driver is discussed. The converter is obtained by integrating two boost
circuits and a half-bridge LLC resonant circuit. A voltage double rectifier circuit is adopted as output
to lower the voltage stress on transformer and the associated core. The two boost circuits work in
boundary conduction mode (BCM) to achieve the power factor correction (PFC). The converter works
in soft-switching mode allowing the power switches to operate in zero-voltage-switching (ZVS) and
the output diodes to operate in zero-current-switching (ZCS). This reduces the switching losses and
enhances the efficiency. The converter features lower voltage stress on the power switches and the bus
voltage is reduced to slightly higher than the peak input voltage. Therefore, the converter can perform
well under high-input-voltage. Here, the DC bus and the output filter capacitances are greatly reduced.
So, electrolytic capacitor-less converter can be realized for a long lifetime LED driver. Simulation results
from PSpice are presented for a 100-W prototype.
Fulltext Optimal location and size of distributed generation to reduce power losses based on differential evolution technique

Noor Izzri Abdul Wahab, Ahmed Sahib Hammadi, Mohammad Lutfi Othman

Pertanika Journal of Science & Technology, 2017;25(101):169-178.
MyJurnal

An electric power system generate electricity to meet demands. Distributed Generation (DG) allows
electricity to be generated in a small capacity where the customer is located. In this paper, multi-objective
functions based on the indices of system performance are formulated and used to determine the best
location. The Differential Evolution technique (DE) has been employed to calculate optimal sizing for
each location. Unity power factor DG model have been studied in this work and the problems solved
with one DG unit. IEEE 14 bus has been used as a test system.
Fulltext Von Hippel–Lindau disease

Juhara Haron, Siti Noorul Arisah Bt Muhamad Nor

Malays Fam Physician, 2017;12(1):29-31.
MyJurnal

Von Hippel–Lindau (VHL) disease is a rare autosomal dominantly inherited multisystem disorder
characterised by the development of a variety of benign and malignant tumours. We report a case of
VHL disease that was inherited by a daughter from her father, who both presented at a young age
with progressive headache and were found to have a posterior fossa haemangioblastoma (HB) on
magnetic resonance imaging (MRI). Multiple benign pancreatic and renal cysts were also noted in
both patients.

MeSH terms: Fathers; Female; Headache; von Hippel-Lindau Disease; Humans; Magnetic Resonance Imaging; Male; Neoplasms; Nuclear Family; Pancreas; Hemangioblastoma; Kidney Diseases, Cystic
Fulltext Pulled/nursemaid’s elbow

Mohd Miswan M. F., Mohamad Saifudin Othman, Ferdhany Muhamad Effendi, Khairul Nizam Rozali, Mohd Ikraam Ibrahim

Malays Fam Physician, 2017;12(1):26-28.
MyJurnal

Nursemaid’s elbow is a radial head subluxation caused by axial traction on the extended arm while
the forearm is pronated, allowing for slippage of the radial head. A 2-year-old boy presented with
pain, swelling and reduced range of movement of the right elbow for 4 days. The mother noted that
the child was moving the right upper limb less often and there was tenderness over the right elbow.
X-ray of the right elbow showed subluxation of the elbow joint with no obvious fracture. A trial of
conservative management was decided upon and the patient was placed on a right elbow backslab
with the right forearm in a supine position. On follow-up, there was no swelling, tenderness or
neurological deficit noted. A repeate x-ray revealed normal findings.

MeSH terms: Arm; Child; Child, Preschool; Elbow; Elbow Joint; Female; Follow-Up Studies; Forearm; Humans; Male; Mothers; Pain; Pronation; Radiography; Radius; Traction; X-Rays; Supine Position; Conservative Treatment
Fulltext Isolation of food-borne pathogen bacteriophages from retail food and environmental sewage

Thung, T.Y, Siti Norshafawatie, B.M.F., Premarathne, J.M.K.J.K., Chang, W.S., Loo, Y.Y., Kuan, C.H., et al.

International Food Research Journal, 2017;24(1):450-454.
MyJurnal

Bacteriophages are the viruses of bacteria and are widely distributed in the biosphere, exhibiting
dramatic manifestations both in liquid cultures and on solid media. In this study, bacteriophages
were isolated from different types of food (beef, chicken meats, cucumber, lettuce, clam,
cockles and shrimp) and sewage samples using 6 reference pathogen strains (Salmonella
Enteritidis, Salmonella Typhimurium, Campylobacter jejuni, Vibrio parahaemolyticus, Listeria
monocytogenes and Escherichia coli). A total of 29 bacteriophage isolates were obtained and
further examined for titer via agar overlay assay. The titers were determined within the range
of 108
to 1011 PFU/mL. Our results showed that diverse of bacteriophages are naturally present
in a variety of foods.
Fulltext Enumeration of Escherichia coli from fresh coconut milk in Negeri Sembilan, West Malaysia

Nurul, F. M., Noorlis, A.,, Nurul Ain, H., Suwaibah, M.

International Food Research Journal, 2017;24(1):455-458.
MyJurnal

Escherichia coli is commonly found in the intestinal tract of human and warm-blooded animal.
Shiga toxin-producing Escherichia coli (STEC) serotype O157:H7 are pathogenic and able to
cause serious health problem to human. In this study, the detection of E. coli from raw coconut
milk was carried out by using the most-probable-number (MPN) and streaked plate methods.
A total of 125 samples were purchased randomly from five hypermarkets and 16 wet markets
in Kuala Pilah, Senawang and Seremban, West Malaysia areas. The samples that contaminate
with E. coli were found to be ranging from 2.4x107
MPN/ml. The results
revealed the presence of E. coli in fresh coconut milk from wet markets and hypermarkets in
Negeri Sembilan. Thus, the result showed high health risk and the need for improving hygienic
standard among food handlers. Therefore, public should be aware and always practice proper
food handling.

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