ORCID Profile
0000-0002-3026-3202
Current Organisation
Universiti Putra Malaysia
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Publisher: Springer Science and Business Media LLC
Date: 02-04-2015
Publisher: Elsevier BV
Date: 03-2009
Publisher: Elsevier BV
Date: 09-2009
Publisher: IEEE
Date: 04-2015
Publisher: Elsevier BV
Date: 2016
Publisher: Elsevier BV
Date: 02-2020
Publisher: Elsevier BV
Date: 2015
Publisher: Elsevier BV
Date: 05-2014
Publisher: IEEE
Date: 07-2017
Publisher: Elsevier BV
Date: 2015
Publisher: Optica Publishing Group
Date: 03-2017
DOI: 10.1364/OE.25.005509
Publisher: Elsevier BV
Date: 03-2018
Publisher: Elsevier BV
Date: 10-2019
Publisher: IEEE
Date: 2003
Publisher: Elsevier BV
Date: 11-2017
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2018
Publisher: Elsevier BV
Date: 05-2019
Publisher: IEEE
Date: 10-2013
Publisher: MDPI
Date: 11-2021
DOI: 10.3390/ECSA-8-11315
Publisher: IEEE
Date: 10-2015
Publisher: IEEE
Date: 10-2009
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 07-2021
Publisher: American Scientific Publishers
Date: 04-2011
DOI: 10.1166/SL.2011.1570
Publisher: Springer Science and Business Media LLC
Date: 17-09-2019
DOI: 10.1038/S41598-019-49891-7
Abstract: The exponential escalation of dengue cases has indeed become a global health crisis. This work elaborates on the development of a biofunctionalized tapered optical fiber (TOF) based sensor with the integration of polyamidoamine (PAMAM) dendrimer for the detection of dengue E protein. The dimension of the TOF generated an evanescent field that was sensitive to any changes in the external medium while the integration of PAMAM promoted more adhesion of bio-recognition molecules anti-DENV II E protein antibodies that were complementary to the targeted protein. This in return created more active sites for the absorption of DENV II E proteins onto the tapered region. The resolution and detection limit of the sensor are 19.53 nm/nM and 1 pM, respectively with K d = 1.02 × 10 −10 M.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2021
Publisher: National Taiwan University
Date: 04-2012
DOI: 10.4015/S1016237212500147
Abstract: Many studies have identified tungsten trioxide (WO 3 ) as a promising candidate for optical gas sensing applications. WO 3 , coated with thin catalytic metals such as Pd , was reported to show a color change from transparent to dark blue upon exposure to oxidizing gas such as hydrogen (H 2 ). Reliable hydrogen sensor is widely used in medical and energy application area. In this work, WO 3 nanostructured thin films were deposited onto sapphire substrates via pulsed laser deposition (PLD) technique by using ArF Excimer laser operating at very short wavelength of 193 nm, the shortest wavelength used in the fabrication of semiconductor oxide thin films. By ablating the target oxides by high energy photons, we could fabricate good crystalline nanostructure thin films. Electron microscopy studies revealed that the uniform and homogeneous WO 3 nanostructured films consist of nanorods of about 50 nm sizes. XRD and Raman studies verified good crystalline formation. Absorbance response toward H 2 gas was investigated for a WO 3 film coated with 25 Å thick palladium (Pd). The Pd/WO 3 nanostructured thin films exhibited excellent gasochromic response toward H 2 when measured in the visible-NIR range at 100°C. As low as 0.06% H 2 concentration was clearly sensed. The larger dynamic response was measured at NIR wavelength of 900 nm as compared to the response at visible wavelength of 500 nm. The dynamic response of the films observed in the range of 500–800 nm showed more significant response toward H 2 with low concentrations (0.06%–1%) than the one at single wavelength. As a result, H 2 with very low concentration was able to be sensed reliably in real time. The response and recovery times were found to be 2 min. The results indicated that the Pd/WO 3 nanorod films on sapphire substrates responded to very low H 2 concentration (0.06%) which is well below its lower explosive level threshold (4%).
Publisher: MDPI AG
Date: 26-02-2015
DOI: 10.3390/S150304749
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 12-2014
Publisher: The Optical Society
Date: 09-01-2019
DOI: 10.1364/OL.44.000307
Publisher: IEEE
Date: 2005
Publisher: European Optical Society
Date: 18-05-2014
Publisher: IEEE
Date: 2005
Publisher: Elsevier BV
Date: 12-2021
Publisher: IOP Publishing
Date: 06-05-2016
Publisher: Springer Science and Business Media LLC
Date: 21-07-2016
Publisher: IOP Publishing
Date: 20-03-2019
Publisher: The Optical Society
Date: 30-01-2015
DOI: 10.1364/OE.23.002837
Publisher: IEEE
Date: 03-2016
Publisher: Elsevier BV
Date: 09-2015
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 12-2015
Publisher: Elsevier BV
Date: 09-2014
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0CP02050H
Abstract: It is well known that WO(3) interacts efficiently with H(2) gas in the presence of noble metals (such as Pd, Pt and Au) at elevated temperatures, changing its optical behaviors and that its crystallinity plays an important role in these interactions. For the first time, we investigated the in situ Raman spectra changes of WO(3) films of different crystal phases, while incorporating Pd catalysts, at elevated temperatures in the presence of H(2). The Pd/WO(3) films were prepared using RF sputtering and subsequently annealed at 300, 400 and 500 °C in air in order to alter the dominant crystal phase. The films were then characterized using SEM, XRD, XPS, and both UV-VIS and Raman spectroscopy. In order to fundamentally study the process, the measurements were conducted when films were interacting with 1% H(2) in synthetic air at elevated s le temperatures (20, 60, 100 and 140 °C). We suggest that the changes of Raman spectra under such conditions to be mainly a function of the crystal phase, transforming from monoclinic to a mix phase of monoclinic and orthorhombic achieved via increasing the annealing temperature. The as-deposited s le consistently shows similar Raman spectra responses at different operating conditions upon H(2) exposure. However, increasing the annealing temperature to 500 °C tunes the optimum H(2) response operating temperature to 60 °C.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 15-03-2020
Publisher: MDPI AG
Date: 06-05-2022
Abstract: Chlorine gas is extensively utilised in industries as both a disinfectant and for wastewater treatment. It has a pungent and irritating odour that is comparable with that of bleach and can cause serious health issues such as headaches and breathing difficulties. Hence, efficiently, and accurately monitoring chlorine gas is critical to ensure that no undesirable incidents occur. Due to its remarkable characteristics, numerous researchers have explored the potential of ferrite nanoparticles as a sensing material for chlorine gas detection. Among several ferrite nanoparticles, nickel ferrite (NiFe2O4) is extensively studied as an inverse spinel structured magnetic material that may be ideal for sensing applications. However, the magnetic characteristics of NiFe2O4 cause agglomeration, which necessitates the use of a substrate for stabilisation. Therefore, nanocellulose (NC), as a green and eco-friendly substrate, is ideal for stabilising bare nickel ferrite nanoparticles. In a novel experiment, nickel ferrite was loaded onto NC as a substrate using in situ deposition. The structure was confirmed by X-ray Diffraction (XRD) analysis, while elemental composition was verified by Energy dispersive X-ray (EDX) analysis. Gas sensing properties were determined by evaluating sensitivity as a function of various regulating factors, such as the amount of nickel ferrite, gas concentration, repeatability, and reusability. In the evaluation, 0.3 g nickel ferrite showed superior response and sensitivity than those of other s les. The achieved response time was around 40 s, while recovery time was about 50 s. This study demonstrates the potential of a nickel ferrite/nanocellulose-based nanocomposite to efficiently monitor chlorine gas.
Publisher: Elsevier BV
Date: 02-2020
Publisher: Springer Science and Business Media LLC
Date: 29-11-2013
Publisher: Elsevier BV
Date: 06-2013
Publisher: Elsevier BV
Date: 09-2013
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2019
Publisher: MDPI
Date: 30-06-2021
Publisher: Elsevier BV
Date: 06-2017
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 02-2021
Publisher: American Scientific Publishers
Date: 04-2011
DOI: 10.1166/SL.2011.1639
Publisher: Elsevier BV
Date: 09-2018
Publisher: IEEE
Date: 09-2014
Publisher: SPIE
Date: 08-09-2010
DOI: 10.1117/12.866420
Publisher: Elsevier BV
Date: 07-2017
Publisher: Elsevier BV
Date: 03-2020
Publisher: IEEE
Date: 11-2017
Publisher: European Optical Society
Date: 09-04-2015
Publisher: IEEE
Date: 07-2019
Publisher: Elsevier BV
Date: 05-2010
Publisher: Wiley
Date: 18-11-2014
DOI: 10.1002/MOP.28768
Publisher: MDPI AG
Date: 24-09-2021
Abstract: The wide availability and ersity of dangerous microbes poses a considerable problem for health professionals and in the development of new healthcare products. Numerous studies have been conducted to develop membrane filters that have antibacterial properties to solve this problem. Without proper protective filter equipment, healthcare providers, essential workers, and the general public are exposed to the risk of infection. A combination of nanotechnology and biosorption is expected to offer a new and greener approach to improve the usefulness of polysaccharides as an advanced membrane filtration material. Nanocellulose is among the emerging materials of this century and several studies have proven its use in filtering microbes. Its high specific surface area enables the adsorption of various microbial species, and its innate porosity can separate various molecules and retain microbial objects. Besides this, the presence of an abundant OH groups in nanocellulose grants its unique surface modification, which can increase its filtration efficiency through the formation of affinity interactions toward microbes. In this review, an update of the most relevant uses of nanocellulose as a new class of membrane filters against microbes is outlined. Key advancements in surface modifications of nanocellulose to enhance its rejection mechanism are also critically discussed. To the best of our knowledge, this is the first review focusing on the development of nanocellulose as a membrane filter against microbes.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 08-2016
Publisher: The Optical Society
Date: 02-08-2017
DOI: 10.1364/OE.25.019382
Publisher: Elsevier BV
Date: 2007
Publisher: Elsevier BV
Date: 12-2016
Publisher: Elsevier BV
Date: 07-2023
Publisher: MDPI AG
Date: 21-08-2020
DOI: 10.3390/S20174713
Abstract: The need for environmental protection and water pollution control has led to the development of different sensors for determining many kinds of pollutants in water. Ammonia nitrogen presence is an important indicator of water quality in environmental monitoring applications. In this paper, a high sensitivity sensor for monitoring ammonia nitrogen concentration in water using a tapered microfiber interferometer (MFI) as a sensor platform and a broad supercontinuum laser as the light source is realized. The MFI is fabricated to the waist diameter of 8 µm producing a strong interference pattern due to the coupling of the fundamental mode with the cladding mode. The MFI sensor is investigated for a low concentration of ammonia nitrogen in water in the wide wavelength range from 1500–1800 nm with a high-power signal provided by the supercontinuum source. The broad source allows optical sensing characteristics of the MFI to be evaluated at four different wavelengths (1505, 1605, 1705, and 1785 nm) upon exposure towards various ammonia nitrogen concentrations. The highest sensitivity of 0.099 nm pm that indicates the wavelength shift is observed at 1785 nm operating wavelength. The response is linear in the ammonia nitrogen range of 5–30 ppm with the best measurement resolution calculated to be 0.5 ppm. The low concentration ammonia nitrogen detected by the MFI in the unique infrared region reveals the potential application of this optical fiber-based sensor for rivers and drinking water monitoring.
Publisher: Elsevier BV
Date: 12-2014
Publisher: MDPI AG
Date: 14-01-2021
DOI: 10.3390/S21020556
Abstract: Ammonia detection in ambient air is critical, given its implication on the environment and human health. In this work, an optical fiber tapered to a 20 µm diameter and coated with graphene oxide was developed for absorbance response monitoring of ammonia at visible (500–700 nm) and near-infrared wavelength regions (700–900 nm). The morphology, surface characteristics, and chemical composition of the graphene oxide s les were confirmed by a field emission scanning electron microscope, an atomic force microscope, X-ray diffraction, and an energy dispersion X-ray. The sensing performance of the graphene oxide-coated optical microfiber sensor towards ammonia at room temperature revealed better absorbance response at the near-infrared wavelength region compared to the visible region. The sensitivity, response and recovery times at the near-infrared wavelength region were 61.78 AU/%, 385 s, and 288 s, respectively. The sensitivity, response and recovery times at the visible wavelength region were 26.99 AU/%, 497 s, and 192 s, respectively. The selectivity of the sensor towards ammonia was affirmed with no response towards other gases.
Publisher: Korean Physical Society
Date: 02-2012
DOI: 10.3938/JKPS.60.393
Publisher: Author(s)
Date: 2019
DOI: 10.1063/1.5089360
Publisher: OSA
Date: 2018
Publisher: American Scientific Publishers
Date: 11-11-2013
DOI: 10.1166/SL.2011.1410
Publisher: IEEE
Date: 04-2018
Publisher: Elsevier BV
Date: 03-2013
Publisher: IEEE
Date: 09-2014
Publisher: IEEE
Date: 09-2014
Publisher: The Optical Society
Date: 16-12-2013
DOI: 10.1364/OE.21.031800
Publisher: IEEE
Date: 10-2013
Publisher: European Optical Society
Date: 29-11-2014
Publisher: IEEE
Date: 10-2013
Publisher: MDPI AG
Date: 14-03-2019
DOI: 10.3390/BIOS9010040
Abstract: This paper describes the development of an integrated system using a dry film resistant (DFR) microfluidic channel consisting of pulsed field dielectrophoretic field-flow-fractionation (DEP-FFF) separation and optical detection. The prototype chip employs the pulse DEP-FFF concept to separate the cells (Escherichia coli and Saccharomyces cerevisiae) from a continuous flow, and the rate of release of the cells was measured. The separation experiments were conducted by changing the pulsing time over a pulsing time range of 2–24 s and a flow rate range of 1.2–9.6 μ L min − 1 . The frequency and voltage were set to a constant value of 1 M Hz and 14 V pk-pk, respectively. After cell sorting, the particles pass the optical fibre, and the incident light is scattered (or absorbed), thus, reducing the intensity of the transmitted light. The change in light level is measured by a spectrophotometer and recorded as an absorbance spectrum. The results revealed that, generally, the flow rate and pulsing time influenced the separation of E. coli and S. cerevisiae. It was found that E. coli had the highest rate of release, followed by S. cerevisiae. In this investigation, the developed integrated chip-in-a lab has enabled two microorganisms of different cell dielectric properties and particle size to be separated and subsequently detected using unique optical properties. Optimum separation between these two microorganisms could be obtained using a longer pulsing time of 12 s and a faster flow rate of 9.6 μ L min − 1 at a constant frequency, voltage, and a low conductivity.
Publisher: Elsevier BV
Date: 07-2013
Publisher: Elsevier BV
Date: 03-2011
Publisher: IEEE
Date: 10-2013
Publisher: Elsevier BV
Date: 08-2017
Publisher: Elsevier BV
Date: 2010
Publisher: Elsevier BV
Date: 11-2014
Publisher: IEEE
Date: 05-2015
Publisher: MDPI AG
Date: 04-05-2015
DOI: 10.3390/S150510452
Publisher: Wiley
Date: 24-04-2018
Abstract: This paper presents the development of tapered optical fiber sensor to detect a specific Leptospira bacteria DNA. The bacteria causes Leptospirosis , a deadly disease but with common early flu‐like symptoms. Optical single mode fiber (SMF) of 125 μm diameter is tapered to produce 12 μm waist diameter and 15 cm length. The novel DNA‐based optical fiber sensor is functionalized by incubating the tapered region with sodium hydroxide (NaOH), (3‐Aminopropyl) triethoxysilane and glutaraldehyde. Probe DNA is immobilized onto the tapered region and subsequently hybridized by its complementary DNA (cDNA). The transmission spectra of the DNA‐based optical fiber sensor are measured in the 1500 to 1600 nm wavelength range. It is discovered that the shift of the wavelength in the SMF sensor is linearly proportional with the increase in the cDNA concentrations from 0.1 to 1.0 nM. The sensitivity of the sensor toward DNA is measured to be 1.2862 nm/nM and able to detect as low as 0.1 fM. The sensor indicates high specificity when only minimal shift is detected for non‐cDNA testing. The developed sensor is able to distinguish between actual DNA of Leptospira serovars (Canicola and Copenhageni) against Clostridium difficile (control s le) at very low (femtomolar) target concentrations.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 12-2018
Publisher: Elsevier BV
Date: 12-2015
Publisher: Springer Science and Business Media LLC
Date: 08-10-2014
Publisher: Elsevier BV
Date: 08-2016
Publisher: IEEE
Date: 09-2014
Publisher: Elsevier BV
Date: 02-2013
Publisher: The Optical Society
Date: 12-05-2017
DOI: 10.1364/OME.7.001858
Publisher: IEEE
Date: 05-2016
Publisher: IEEE
Date: 11-2006
Publisher: IEEE
Date: 11-2006
Publisher: MDPI AG
Date: 14-02-2023
DOI: 10.3390/BIOS13020270
Abstract: Biosensors are central to diagnostic and medicinal applications, especially in terms of monitoring, managing illness, and public health. Microfiber-based biosensors are known to be capable of measuring both the presence and behavior of biological molecules in a highly sensitive manner. In addition, the flexibility of microfiber in supporting a variety of sensing layer designs and the integration of nanomaterials with biorecognition molecules brings immense opportunity for specificity enhancement. This review paper aims to discuss and explore different microfiber configurations by highlighting their fundamental concepts, fabrication processes, and performance as biosensors.
Publisher: IEEE
Date: 10-2013
Publisher: The Optical Society
Date: 30-07-2013
DOI: 10.1364/OE.21.018724
Publisher: Elsevier BV
Date: 2011
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 12-2014
Publisher: Penerbit UTM Press
Date: 21-02-2016
DOI: 10.11113/JT.V78.7526
Abstract: The presence of plumbous (Pb2+) in Irrigation water is harmful for the environment as well as human health. Herein, a simple yet effective sensor for Pb2+ detection is presented utilizing a surface plasmon resonance technique. The proposed sensor consists of a combination of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) were attached to a gold layer offers a new option for heavy metal detection. The EDC/NHS works as a sensing layer that able to detect Pb2+ down to 15 ppm that matches with the United States Environment Protection Agency.
Publisher: Hindawi Limited
Date: 26-09-2018
DOI: 10.1155/2018/2107898
Abstract: In this paper, carbon nanotubes (CNTs) were functionalized by acid treatment and further functionalized with dodecylamine and were designated as CNT-carboxylic and CNT-amide, respectively. Then, functionalized CNTs produced were characterized with various methods to verify the attachment of a functional group. Performance of the functionalized CNTs in the detection of benzene gas was monitored at room temperature. The s le was dropped cast on the interdigitated transducer (IDT), and the changes in resistivity were recorded by a digital multimeter in a customized chamber under controlled humidity (∼55%) environment. Based on the findings, it showed that the functionalized CNTs provide an extra active area for interaction between the gas analyte and CNTs, thus increasing their response and improving the sensitivity of the sensing material.
Publisher: MDPI AG
Date: 17-11-2022
DOI: 10.3390/MA15228167
Abstract: Gaseous pollutants such as hydrogen gas (H
Publisher: IEEE
Date: 11-2017
No related grants have been discovered for Mohd Yaacob.