Displaying publications 1 - 20 of 27 in total

  1. Kashif M, Bakar AA, Arsad N, Shaari S
    Sensors (Basel), 2014 Aug 28;14(9):15914-38.
    PMID: 25171117 DOI: 10.3390/s140915914
    Surface plasmon resonance (SPR) is a novel optical sensing technique with a unique ability to monitor molecular binding in real-time for biological and chemical sensor applications. Interferometry is an excellent tool for accurate measurement of SPR changes, the measurement and comparison is made for the sensitivity, dynamic range and resolution of the different analytes using interferometry techniques. SPR interferometry can also employ phase detection in addition to the amplitude of the reflected light wave, and the phase changes more rapidly compared with other approaches, i.e., intensity, angle and wavelength. Therefore, the SPR phase interferometer offers the advantages of spatial phase resolution and high sensitivity. This work discusses the advancements in interferometric SPR methods to measure the phase shifts due to refractive index changes. The main application areas of SPR sensors are demonstrated, i.e., the Fabry-Perot interferometer, Michelson interferometer and Mach-Zehnder interferometer, with different configurations. The three interferometers are discussed in detail, and solutions are suggested to enhance the performance parameters that will aid in future biological and chemical sensors.
  2. Abushagur AA, Arsad N, Reaz MI, Bakar AA
    Sensors (Basel), 2014;14(4):6633-65.
    PMID: 24721774 DOI: 10.3390/s140406633
    The large interest in utilising fibre Bragg grating (FBG) strain sensors for minimally invasive surgery (MIS) applications to replace conventional electrical tactile sensors has grown in the past few years. FBG strain sensors offer the advantages of optical fibre sensors, such as high sensitivity, immunity to electromagnetic noise, electrical passivity and chemical inertness, but are not limited by phase discontinuity or intensity fluctuations. FBG sensors feature a wavelength-encoding sensing signal that enables distributed sensing that utilises fewer connections. In addition, their flexibility and lightness allow easy insertion into needles and catheters, thus enabling localised measurements inside tissues and blood. Two types of FBG tactile sensors have been emphasised in the literature: single-point and array FBG tactile sensors. This paper describes the current design, development and research of the optical fibre tactile techniques that are based on FBGs to enhance the performance of MIS procedures in general. Providing MIS or microsurgery surgeons with accurate and precise measurements and control of the contact forces during tissues manipulation will benefit both surgeons and patients.
  3. Abushagur AAG, Arsad N, Bakar AAA
    Sensors (Basel), 2021 Mar 12;21(6).
    PMID: 33809028 DOI: 10.3390/s21062002
    This work investigates a new interrogation method of a fiber Bragg grating (FBG) sensor based on longer and shorter wavelengths to distinguish between transversal forces and temperature variations. Calibration experiments were carried out to examine the sensor's repeatability in response to the transversal forces and temperature changes. An automated calibration system was developed for the sensor's characterization, calibration, and repeatability testing. Experimental results showed that the FBG sensor can provide sensor repeatability of 13.21 pm and 17.015 pm for longer and shorter wavelengths, respectively. The obtained calibration coefficients expressed in the linear model using the matrix enabled the sensor to provide accurate predictions for both measurements. Analysis of the calibration and experiment results implied improvements for future work. Overall, the new interrogation method demonstrated the potential to employ the FBG sensing technique where discrimination between two/three measurands is needed.
  4. Tan X, Li M, Arsad N, Wen X, Lu H
    Rev Sci Instrum, 2018 Mar;89(3):035005.
    PMID: 29604764 DOI: 10.1063/1.5017639
    Hydrogen is a kind of promising clean energy resource with a wide application prospect, which will, however, cause a serious security issue upon the leakage of hydrogen gas. The measurement of its concentration is of great significance. In a traditional approach of ultrasonic hydrogen sensing, a temperature drift of 0.1 °C results in a concentration error of about 250 ppm, which is intolerable for trace amount of gas sensing. In order to eliminate the influence brought by temperature drift, we propose a feasible approach named as linear compensation algorithm, which utilizes the linear relationship between the pulse count and temperature to compensate for the pulse count error (ΔN) caused by temperature drift. Experimental results demonstrate that our proposed approach is capable of improving the measurement accuracy and can easily detect sub-100 ppm of hydrogen concentration under variable temperature conditions.
  5. Al-Obaidy R, Haider AJ, Al-Musawi S, Arsad N
    Sci Rep, 2023 Feb 23;13(1):3180.
    PMID: 36823237 DOI: 10.1038/s41598-023-30221-x
    Fibrosarcoma is a rare type of cancer that affects cells known as fibroblasts that are malignant, locally recurring, and spreading tumor in fibrous tissue. In this work, an iron plate immersed in an aqueous solution of double added deionized water, supplemented with potassium permanganate solution (KMnO4) was carried out by the pulsed laser ablation in liquid method (PLAIL). Superparamagnetic iron oxide nanoparticles (SPIONs) were synthesized using different laser wavelengths (1064, 532, and 266 nm) at a fluence of 28 J/cm2 with 100 shots of the iron plate to control the concentration, shape and size of the prepared high-stability SPIONs. The drug nanocarrier was synthesized by coating SPION with paclitaxel (PTX)-loaded chitosan (Cs) and polyethylene glycol (PEG). This nanosystem was functionalized by receptors that target folate (FA). The physiochemical characteristics of SPION@Cs-PTX-PEG-FA nanoparticles were evaluated and confirmed by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-Ray diffraction (XRD), atomic force microscopy (AFM), and dynamic light scattering (DLS) methods. Cell internalization, cytotoxicity assay (MTT), apoptosis induction, and gene expression of SPION@Cs-PTX-PEG-FA were estimated in fibrosarcoma cell lines, respectively. In vivo studies used BALB/c tumor-bearing mice. The results showed that SPION@Cs-PTX-PEG-FA exhibited suitable physical stability, spherical shape, desirable size, and charge. SPION@Cs-PTX-PEG-FA inhibited proliferation and induced apoptosis of cancer cells (P 
  6. Ting SL, Saimon R, Rahman MM, Safii R, Ho SL, John N, et al.
    Med J Malaysia, 2020 11;75(6):649-654.
    PMID: 33219172
    BACKGROUND AND OBJECTIVE: Physical and behavioural problems from extended usage of electronic devices are issues among primary school children. This study is aimed to investigate the prevalence of physical and behavioural complaints arising from the electronic device usage and to identify the potential factors that predicted the complaints.

    METHODS: This was a primary school-based cross-sectional study using multistage cluster sampling, conducted at Bau district in Sarawak, Malaysia in 40 primary schools. A questionnaire was used to collect information of usage pattern in insufficient lighting, timing and position. The physical and behavioural complaints were traced. Data analysis was performed using SPSS version 22. A p-value < 0.05 with 95% CI was considered as statistically significant.

    RESULTS: About 52.8% of the 569 students used digital devices in a bright room, 69.8% in the day time and 54.4% in sitting position. The physical complaints were headache (32.9%), neck, shoulder and back pain (32.9%) followed by by eye strain (31.8%). Regarding behavioural problems, 25.7% of the students had loss of interest in study and outdoor activities (20.7%), skipped meals (19.0%) and arguments/disagreements with parents (17.9%). After logistic regression analysis, the lying position (OR=1.71, 95% CI: 1.096, 2.688) and darkroom lighting (OR=2.323 95% CI: 1.138, 4.744) appeared to be potential predictors of the complaint.

    CONCLUSION: One-quarter of the students studied experienced physical complaints, and one-fifth had behavioural problems associated with the use of electronic devices. Lying position and darkroom lighting are the potential predictors of complaints. Therefore, we suggest that the children should use electronic devices in the sitting position with adequate room lighting.

  7. Letchumanan M, Anour AA, Ganapathy SS, Harry S, Nik Lah NSH, Arsad N, et al.
    Med J Malaysia, 2021 03;76(2):131-137.
    PMID: 33742618
    OBJECTIVES: To recognize the radiographic patterns of coronavirus disease 2019 (COVID-19) in Malaysia.

    MATERIALS AND METHODS: Chest radiographs of patients confirmed with COVID-19 in Hospital Tawau, Sabah, Malaysia were retrospectively analyzed by two radiologists. The radiographic pattern, distribution among subgroups and evolution of the disease over time were determined.

    RESULTS: Among the 82 patients studied, 65 (79.3%) were males. Mean age of our cohorts was 37 ± 15 years. Baseline chest radiographs were abnormal in 37 patients (45.1%). Over half (52.9%) of the symptomatic patients had abnormal baseline radiograph. Among the children, patients with comorbidities, and patients 60 years of age and above, the abnormal radiographs were 14.3%, 71.4% and 69.3% respectively. Ground glass opacities were the commonest abnormal radiographic feature (35.4%), were peripherally located (35.4%) with predilection for the lower zones (29.3%). Most radiographic abnormalities were multifocal (20.7%) and frequently located in the left lung (19.5%). Radiographic recovery was observed in 15 of 18 patients (83%). Computed tomography (CT) scan demonstrated greater extent of the disease than observed in radiographs of the same patient.

    CONCLUSIONS: COVID-19 pneumonia presented with a specific radiographic pattern in our cohort of patients, comprising of ground glass opacities in peripheral and basilar distribution, affecting a single lung field and was observed in both symptomatic and asymptomatic patients. Chest radiograph is a useful adjunct screening tool, and in combination with clinical and epidemiological assessment may facilitate in early diagnosis of COVID-19 pneumonia.

  8. Haque F, Reaz MBI, Ali SHM, Arsad N, Chowdhury MEH
    Sci Rep, 2020 12 10;10(1):21770.
    PMID: 33303857 DOI: 10.1038/s41598-020-78787-0
    Despite the availability of various clinical trials that used different diagnostic methods to identify diabetic sensorimotor polyneuropathy (DSPN), no reliable studies that prove the associations among diagnostic parameters from two different methods are available. Statistically significant diagnostic parameters from various methods can help determine if two different methods can be incorporated together for diagnosing DSPN. In this study, a systematic review, meta-analysis, and trial sequential analysis (TSA) were performed to determine the associations among the different parameters from the most commonly used electrophysiological screening methods in clinical research for DSPN, namely, nerve conduction study (NCS), corneal confocal microscopy (CCM), and electromyography (EMG), for different experimental groups. Electronic databases (e.g., Web of Science, PubMed, and Google Scholar) were searched systematically for articles reporting different screening tools for diabetic peripheral neuropathy. A total of 22 studies involving 2394 participants (801 patients with DSPN, 702 controls, and 891 non-DSPN patients) were reviewed systematically. Meta-analysis was performed to determine statistical significance of difference among four NCS parameters, i.e., peroneal motor nerve conduction velocity, peroneal motor nerve amplitude, sural sensory nerve conduction velocity, and sural sensory nerve amplitude (all p 
  9. Kamaruddin NH, Bakar AAA, Mobarak NN, Zan MSD, Arsad N
    Sensors (Basel), 2017 Oct 06;17(10).
    PMID: 28984826 DOI: 10.3390/s17102277
    The study of binding affinity is essential in surface plasmon resonance (SPR) sensing because it allows researchers to quantify the affinity between the analyte and immobilised ligands of an SPR sensor. In this study, we demonstrate the derivation of the binding affinity constant, K, for Pb2+and Hg2+ions according to their SPR response using a gold/silver/gold/chitosan-graphene oxide (Au/Ag/Au/CS-GO) sensor for the concentration range of 0.1-5 ppm. The higher affinity of Pb2+to binding with the CS-GO sensor explains the outstanding sensitivity of 2.05 °ppm-1against 1.66 °ppm-1of Hg2+. The maximum signal-to-noise ratio (SNR) upon detection of Pb2+is 1.53, and exceeds the suggested logical criterion of an SNR. The Au/Ag/Au/CS-GO SPR sensor also exhibits excellent repeatability in Pb2+due to the strong bond between its functional groups and this cation. The adsorption data of Pb2+and Hg2+on the CS-GO sensor fits well with the Langmuir isotherm model where the affinity constant, K, of Pb2+and Hg2+ions is computed. The affinity of Pb2+ions to the Au/Ag/Au/CS-GO sensor is significantly higher than that of Hg2+based on the value of K, 7 × 10⁵ M-1and 4 × 10⁵ M-1, respectively. The higher shift in SPR angles due to Pb2+and Hg2+compared to Cr3+, Cu2+and Zn2+ions also reveals the greater affinity of the CS-GO SPR sensor to them, thus supporting the rationale for obtaining K for these two heavy metals. This study provides a better understanding on the sensing performance of such sensors in detecting heavy metal ions.
  10. Taha BA, Mashhadany YA, Al-Jumaily AHJ, Zan MSDB, Arsad N
    Viruses, 2022 Oct 28;14(11).
    PMID: 36366485 DOI: 10.3390/v14112386
    The SARS-CoV-2 virus is responsible for the rapid global spread of the COVID-19 disease. As a result, it is critical to understand and collect primary data on the virus, infection epidemiology, and treatment. Despite the speed with which the virus was detected, studies of its cell biology and architecture at the ultrastructural level are still in their infancy. Therefore, we investigated and analyzed the viral morphometry of SARS-CoV-2 to extract important key points of the virus's characteristics. Then, we proposed a prediction model to identify the real virus levels based on the optimization of a full recurrent neural network (RNN) using transmission electron microscopy (TEM) images. Consequently, identification of virus levels depends on the size of the morphometry of the area (width, height, circularity, roundness, aspect ratio, and solidity). The results of our model were an error score of training network performance 3.216 × 10-11 at 639 epoch, regression of -1.6 × 10-9, momentum gain (Mu) 1 × 10-9, and gradient value of 9.6852 × 10-8, which represent a network with a high ability to predict virus levels. The fully automated system enables virologists to take a high-accuracy approach to virus diagnosis, prevention of mutations, and life cycle and improvement of diagnostic reagents and drugs, adding a point of view to the advancement of medical virology.
  11. Lokman NF, Azeman NH, Suja F, Arsad N, Bakar AAA
    Sensors (Basel), 2019 Nov 25;19(23).
    PMID: 31775327 DOI: 10.3390/s19235159
    The detection of Pb(II) ions in a river using the surface plasmon resonance (SPR)-based silver (Ag) thin film technique was successfully developed. Chitosan-graphene oxide (CS-GO) was coated on top of the Ag thin film surface and acted as the active sensing layer for Pb(II) ion detection. CS-GO was synthesized and characterized, and the physicochemical properties of this material were studied prior to integration with the SPR. In X-ray photoelectron spectroscopy (XPS), the appearance of the C=O, C-O, and O-H functional groups at 531.2 eV and 532.5 eV, respectively, confirms the success of CS-GO nanocomposite synthesis. A higher surface roughness of 31.04 nm was observed under atomic force microscopy (AFM) analysis for Ag/CS-GO thin film. The enhancement in thin film roughness indicates that more adsorption sites are available for Pb(II) ion binding. The SPR performance shows a good sensor sensitivity for Ag/CS-GO with 1.38° ppm-1 ranging from 0.01 to 5.00 ppm of standard Pb(II) solutions. At lower concentrations, a better detection accuracy was shown by SPR using Ag/CS-GO thin film compared to Ag/CS thin film. The SPR performance using Ag/CS-GO thin film was further evaluated with real water samples collected from rivers. The results are in agreement with those of standard Pb(II) ion solution, which were obtained at incidence angles of 80.00° and 81.11° for local and foreign rivers, respectively.
  12. Arsad N, Abd Razak N, Omar MH, Shafiee MN, Kalok A, Cheah FC, et al.
    PMID: 35564596 DOI: 10.3390/ijerph19095201
    This exploratory study aimed to evaluate the effects of antenatal corticosteroids in singleton pregnancies of Asian women prior to elective cesarean section (CS) at early term on neonatal respiratory outcomes.

    METHODS: This is a pilot and pragmatic randomized trial conducted at a university hospital in Malaysia. Women with singleton pregnancies planned for elective CS between 37+0 and 38+6 weeks gestation were randomly allocated into the intervention group, where they received two doses of IM dexamethasone 12 mg of 12 h apart, 24 h prior to surgery OR into the standard care, control group, and both groups received the normal routine antenatal care. The primary outcome measures were neonatal respiratory illnesses, NICU admission and length of stay.

    RESULTS: A total of 189 patients were recruited, 93 women in the intervention group and 96 as controls. Between the steroid and control groups, the mean gestation at CS was similar, 266.1 ± 3.2 days (38 weeks) vs. 265.8 ± 4.0 days (37+6 weeks), p = 0.53. The mean birthweight of infants was 3.06 ± 0.41 kg vs. 3.04 ± 0.37 kg, p = 0.71. Infants with respiratory morbidities were primarily due to transient tachypnea of newborn (9.7% vs. 6.3%), and congenital pneumonia (1.1% vs. 3.1%) but none had respiratory distress syndrome. Only four infants required NICU admission (2.2% vs. 3.1%, p = 0.63). Their average length of stay was not statistically different; 3.5 ± 2.1 days vs. 5.7 ± 1.5 days, p = 0.27.

    CONCLUSIONS: Elective CS at early term before 39 weeks was associated with a modest overall incidence of neonatal respiratory illness (10.1%) in this Asian population. Antenatal dexamethasone did not diminish infants needing respiratory support, NICU admission and length of stay.

  13. Fadhel MM, Hamzah AE, Abd Aziz N, Dzulkefly Zan MS, Arsad N
    Heliyon, 2023 Oct;9(10):e20678.
    PMID: 37860525 DOI: 10.1016/j.heliyon.2023.e20678
    This study demonstrates a linearly polarized Er-doped fiber laser system featuring an all-polarization-maintaining (all-PM) architecture. Short pulses were generated by Q-switching operation based on drop-casting rhenium disulfide (ReS2) saturable absorber (SA) onto a fiber connector placed inside the laser cavity. The Q-switching operation of the laser was able to self-start at a low (23 mW) threshold power of the pump and without the need to use a polarization controller. The proposed laser was able to produce stable pulses with a center wavelength and 3-dB bandwidth of 1558.4 nm and 0.13 nm, respectively. The shortest pulse duration measured (2.8 μs) was achieved at a repetition rate of 37.6 kHz while the highest average output power and pulse energy were 2.2 mW and 76.5 nJ, respectively. Furthermore, as the cavity of the laser was designed to be all-PM the laser that it produced was linearly polarized and had a degree of polarization (DOP) at the level of 94.5 % and 40 dB polarization extinction ratio (PER). Therefore, the proposed laser is a suitable light source for optical applications in environments that are complex.
  14. Taha BA, Al Mashhadany Y, Hafiz Mokhtar MH, Dzulkefly Bin Zan MS, Arsad N
    Sensors (Basel), 2020 Nov 26;20(23).
    PMID: 33256085 DOI: 10.3390/s20236764
    Timely detection and diagnosis are essentially needed to guide outbreak measures and infection control. It is vital to improve healthcare quality in public places, markets, schools and airports and provide useful insights into the technological environment and help researchers acknowledge the choices and gaps available in this field. In this narrative review, the detection of coronavirus disease 2019 (COVID-19) technologies is summarized and discussed with a comparison between them from several aspects to arrive at an accurate decision on the feasibility of applying the best of these techniques in the biosensors that operate using laser detection technology. The collection of data in this analysis was done by using six reliable academic databases, namely, Science Direct, IEEE Xplore, Scopus, Web of Science, Google Scholar and PubMed. This review includes an analysis review of three highlights: evaluating the hazard of pandemic COVID-19 transmission styles and comparing them with Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS) to identify the main causes of the virus spreading, a critical analysis to diagnose coronavirus disease 2019 (COVID-19) based on artificial intelligence using CT scans and CXR images and types of biosensors. Finally, we select the best methods that can potentially stop the propagation of the coronavirus pandemic.
  15. Taha BA, Al Mashhadany Y, Al-Jubouri Q, Haider AJ, Chaudhary V, Apsari R, et al.
    Microbes Infect, 2023;25(8):105187.
    PMID: 37517605 DOI: 10.1016/j.micinf.2023.105187
    Comprehending the morphological disparities between SARS-CoV-2 and SARS-CoV viruses can shed light on the underlying mechanisms of infection and facilitate the development of effective diagnostic tools and treatments. Hence, this study aimed to conduct a comprehensive analysis and comparative assessment of the morphology of SARS-CoV-2 and SARS-CoV using transmission electron microscopy (TEM) images. The dataset encompassed 519 isolated SARS-CoV-2 images obtained from patients in Italy (INMI) and 248 isolated SARS-CoV images from patients in Germany (Frankfurt). In this paper, we employed TEM images to scrutinize morphological features, and the outcomes were contrasted with those of SARS-CoV viruses. The findings reveal disparities in the characteristics of SARS-CoV-2 and SARS-CoV, such as envelope protein (E) 98.6 and 102.2 nm, length of spike protein (S) 10.11 and 9.50 nm, roundness 0.86 and 0.88, circularity 0.78 and 0.76, and area sizes 25145.54 and 38591.35 pixels, respectively. In conclusion, these results will augment the identification of virus subtypes, aid in the study of antiviral medications, and enhance our understanding of disease progression and the virus life cycle. Moreover, these findings have the potential to assist in the development of more accurate epidemiological prediction models for COVID-19, leading to better outbreak management and saving lives.
  16. Taha BA, Addie AJ, Kadhim AC, Azzahran AS, Haider AJ, Chaudhary V, et al.
    Mikrochim Acta, 2024 Apr 08;191(5):250.
    PMID: 38587660 DOI: 10.1007/s00604-024-06314-3
    Rapid technological advancements have created opportunities for new solutions in various industries, including healthcare. One exciting new direction in this field of innovation is the combination of skin-based technologies and augmented reality (AR). These dermatological devices allow for the continuous and non-invasive measurement of vital signs and biomarkers, enabling the real-time diagnosis of anomalies, which have applications in telemedicine, oncology, dermatology, and early diagnostics. Despite its many potential benefits, there is a substantial information vacuum regarding using flexible photonics in conjunction with augmented reality for medical purposes. This review explores the current state of dermal augmented reality and flexible optics in skin-conforming sensing platforms by examining the obstacles faced thus far, including technical hurdles, demanding clinical validation standards, and problems with user acceptance. Our main areas of interest are skills, chiroptical properties, and health platform applications, such as optogenetic pixels, spectroscopic imagers, and optical biosensors. My skin-enhanced spherical dichroism and powerful spherically polarized light enable thorough physical inspection with these augmented reality devices: diabetic tracking, skin cancer diagnosis, and cardiovascular illness: preventative medicine, namely blood pressure screening. We demonstrate how to accomplish early prevention using case studies and emergency detection. Finally, it addresses real-world obstacles that hinder fully realizing these materials' extraordinary potential in advancing proactive and preventative personalized medicine, including technical constraints, clinical validation gaps, and barriers to widespread adoption.
  17. Taha BA, Al Mashhadany Y, Bachok NN, Ashrif A Bakar A, Hafiz Mokhtar MH, Dzulkefly Bin Zan MS, et al.
    Diagnostics (Basel), 2021 Jun 19;11(6).
    PMID: 34205401 DOI: 10.3390/diagnostics11061119
    The propagation of viruses has become a global threat as proven through the coronavirus disease (COVID-19) pandemic. Therefore, the quick detection of viral diseases and infections could be necessary. This study aims to develop a framework for virus diagnoses based on integrating photonics technology with artificial intelligence to enhance healthcare in public areas, marketplaces, hospitals, and airfields due to the distinct spectral signatures from lasers' effectiveness in the classification and monitoring of viruses. However, providing insights into the technical aspect also helps researchers identify the possibilities and difficulties in this field. The contents of this study were collected from six authoritative databases: Web of Science, IEEE Xplore, Science Direct, Scopus, PubMed Central, and Google Scholar. This review includes an analysis and summary of laser techniques to diagnose COVID-19 such as fluorescence methods, surface-enhanced Raman scattering, surface plasmon resonance, and integration of Raman scattering with SPR techniques. Finally, we select the best strategies that could potentially be the most effective methods of reducing epidemic spreading and improving healthcare in the environment.
  18. Elgaud MM, Zan MSD, Abushagur AAG, Hamzah AE, Mokhtar MHH, Arsad N, et al.
    Sensors (Basel), 2021 Jun 23;21(13).
    PMID: 34201845 DOI: 10.3390/s21134299
    For almost a half-decade, the unique autocorrelation properties of Golay complementary pairs (GCP) have added a significant value to the key performance of conventional time-domain multiplexed fiber Bragg grating sensors (TDM-FBGs). However, the employment of the unipolar form of Golay coded TDM-FBG has suffered from several performance flaws, such as limited improvement of the signal-to-noise ratio (SNIR), noisy backgrounds, and distorted signals. Therefore, we propose and experimentally implement several digital filtering techniques to mitigate such limitations. Moving averages (MA), Savitzky-Golay (SG), and moving median (MM) filters were deployed to process the signals from two low reflectance FBG sensors located after around 16 km of fiber. The first part of the experiment discussed the sole deployment of Golay codes from 4 bits to 256 bits in the TDM-FBG sensor. As a result, the total SNIR of around 8.8 dB was experimentally confirmed for the longest 256-bit code. Furthermore, the individual deployment of MA, MM, and SG filters within the mentioned decoded sequences secured a further significant increase in SNIR of around 4, 3.5, and 3 dB, respectively. Thus, the deployment of the filtering technique alone resulted in at least four times faster measurement time (equivalent to 3 dB SNIR). Overall, the experimental analysis confirmed that MM outperformed the other two techniques in better signal shape, fastest signal transition time, comparable SNIR, and capability to maintain high spatial resolution.
  19. Fadhel MM, Ali N, Rashid H, Sapiee NM, Hamzah AE, Zan MSD, et al.
    Nanomaterials (Basel), 2021 Sep 12;11(9).
    PMID: 34578683 DOI: 10.3390/nano11092367
    Rhenium Disulfide (ReS2) has evolved as a novel 2D transition-metal dichalcogenide (TMD) material which has promising applications in optoelectronics and photonics because of its distinctive anisotropic optical properties. Saturable absorption property of ReS2 has been utilized to fabricate saturable absorber (SA) devices to generate short pulses in lasers systems. The results were outstanding, including high-repetition-rate pulses, large modulation depth, multi-wavelength pulses, broadband operation and low saturation intensity. In this review, we emphasize on formulating SAs based on ReS2 to produce pulsed lasers in the visible, near-infrared and mid-infrared wavelength regions with pulse durations down to femtosecond using mode-locking or Q-switching technique. We outline ReS2 synthesis techniques and integration platforms concerning solid-state and fiber-type lasers. We discuss the laser performance based on SAs attributes. Lastly, we draw conclusions and discuss challenges and future directions that will help to advance the domain of ultrafast photonic technology.
  20. Taha BA, Ali N, Sapiee NM, Fadhel MM, Mat Yeh RM, Bachok NN, et al.
    Biosensors (Basel), 2021 Jul 27;11(8).
    PMID: 34436055 DOI: 10.3390/bios11080253
    Understanding environmental information is necessary for functions correlated with human activities to improve healthcare quality and reduce ecological risk. Tapered optical fibers reduce some limitations of such devices and can be considerably more responsive to fluorescence and absorption properties changes. Data have been collected from reliable sources such as Science Direct, IEEE Xplore, Scopus, Web of Science, PubMed, and Google Scholar. In this narrative review, we have summarized and analyzed eight classes of tapered-fiber forms: fiber Bragg grating (FBG), long-period fiber grating (LPFG), Mach-Zehnder interferometer (MZI), photonic crystals fiber (PCF), surface plasmonic resonance (SPR), multi-taper devices, fiber loop ring-down technology, and optical tweezers. We evaluated many issues to make an informed judgement about the viability of employing the best of these methods in optical sensors. The analysis of performance for tapered optical fibers depends on four mean parameters: taper length, sensitivity, wavelength scale, and waist diameter. Finally, we assess the most potent strategy that has the potential for medical and environmental applications.
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