Now showing 1 - 8 of 8
  • Publication
    Machine learning approaches for stem cells
    (Springer, 2023) ;
    Tien Dung Do
    ;
    Wan Safwani Wan Kamarul Zaman
    ;
    Effirul Ikhwan Ramlan
    Purpose of Review: Machine learning (ML) enables high-throughput analysis of multimodal data generated from stem cell experiments such as gene expression data, images of cells, or proteomic data. In this review, we analyse the progression of ML adaptation in advancing the field of stem cell research. Recent Findings: On the one hand, the field of stem cell phenotypic characterisation is experiencing a significant growth, largely due to the successful implementation of deep networks in domains with similar problem characteristics (i.e., rapid advances of the image recognition field). On the other hand, genotypic characterisation is gradually gaining traction as researchers are beginning to apply ML to understand the genetic and molecular mechanisms behind stem cell behaviour. Summary: The use of advanced machine learning techniques, such as deep networks, is demonstrating promising results in phenotypic stem cell characterisation, although it is still lagging slightly in genotypic characterisation. Despite this progress, significant challenges persist, including ensuring the interpretability of ML models, limited availability of annotated datasets, improving the accuracy and quality of training data, and navigating ethical considerations.
  • Publication
    Dual band CPW pentagonal island with modified sierpinski gasket structure at 3.5 GHz and 5.8 GHz
    (IEEE, 2024-01)
    Amier Hafizun Ab Rashid
    ;
    Badrul Hisham Ahmad
    ;
    Nornikman Hassan
    ;
    ;
    Mohamad Zoinol Abidin Abd Aziz
    ;
    Nurzaima Mahmod
    In this work, a dual-band pentagonal island antenna is proposed for WiMAX 3.5 GHz and WLAN 5.8 GHz applications. Firstly, the basic CPW pentagonal island antenna, Antenna A, is constructed on a 1.6 mm thick FR-4 substrate with a dielectric constant of 4.3 and a copper thickness of 0.035 mm. This antenna contains a pentagonal island with five mini structures of pentagonal island. Then, for Antenna B, a modification is made to the shading made of the Sierpinski gasket structure in the mini structure of the pentagonal island. For simulation Antenna B, it shows the simulation performance of 3.52 GHz and 5.93 GHz with return loss of - 24.84 dB and – 27.94 dB. For the measurement result of Antenna B at desired frequencies of WiMAX 3.5 GHz and WLAN 5.8 GHz, it shows a good performance of – 17.25 dB and – 19.35 dB, respectively.
  • Publication
    Parametric studies of CPW pentagonal Sierpinski gasket fractal patch antenna
    (Polish Electrical Association, 2023)
    Amier Hafizun Ab Rashid
    ;
    Badrul Hisham Ahmad
    ;
    Mohamad Zoinol Abidin Abd Aziz
    ;
    Nonikman Hassan
    ;
    The parametric study on a dual band CPW Pentagonal Sierpinski gasket fractal patch antenna for WiMAX and WLAN applications is presented in this work. In order to accomplish and advantages of multi-band, broadband, high gain, and low-profile antennas, novel geometries must be developed due to the limits of the conventional antenna design, Sierpinski gasket fractal structure is chosen to improve the antenna performance. The work began with Antenna A as the initiator step with pentagonal patch with CPW technique. Then, it goes with Antenna B was the first iteration stages with pentagonal slot. After that, the work continued by five different parametric studies are chosen in this work to define the effect of different dimensions of the patch antenna. The first and second parametric study works include a different width and length size of the patch antenna at Antenna A. The other three involved in the Antenna B, are including the different dimensions of the CPW/feeding antenna gap, feed line, and lastly the slot width dimension. At 3.5 GHz and 5.8 GHz, the antenna's aimed frequencies are - 31.70 dB and - 22.00 dB, respectively, and these values are feasible for WiMAX and WLAN operation.
  • Publication
    A Numerical Study of Collective Cell Migration in a Microchannel Driven by Surface Acoustic Wave (SAW) Device
    Collective cell migration is involved in a variety of biological contexts, including tissue morphogenesis, wound healing, and cancer invasion. Many studies have revealed that chemical, mechanical, and electrical stimulation all affect cell migration. Although an acoustic stimulus has been shown to influence cell migration in the past, the underlying mechanism is still unknown. A computational model that accounts for acoustic-structure interaction was constructed in this study to simulate the formation of a surface acoustic wave (SAW) field and the application of the acoustic pressure field on collective cell migration. A group of cells within a microchannel device and two ports of interdigitated transducers (IDTs) with different wavelengths were modeled. The stresses within cells were investigated as it was influenced by substrate displacement and pressure acoustic in the cell media generated by the SAW device. As a result, we observed the local stress within cells near the solid-fluid interfaces. For propagating SAW, the shorter wavelength of IDTs (600 μm) attributed to high stress at the cell's top and bottom as compared to the SAW device with the longer wavelength (1000 μm). The standing SAW occurred underneath collective cells. The results of standing SAW on cell stress at the bottom confirm that the SAW device can be useful to regulate the abnormalities cellular activities associated with cell migration.
      5  31
  • Publication
    Current development in interdigital transducer (IDT) surface acoustic wave devices for live cell in vitro studies: A review
    Acoustics have a wide range of uses, from noise-cancelling to ultrasonic imaging. There has been a surge in interest in developing acoustic-based approaches for biological and biomedical applications in the last decade. This review focused on the application of surface acoustic waves (SAW) based on interdigital transducers (IDT) for live-cell investigations, such as cell manipulation, cell separation, cell seeding, cell migration, cell characteristics, and cell behaviours. The approach is also known as acoustofluidic, because the SAW device is coupled with a microfluidic system that contains live cells. This article provides an overview of several forms of IDT of SAW devices on recently used cells. Conclusively, a brief viewpoint and overview of the future application of SAW techniques in live-cell investigations were presented.
      4  40
  • Publication
    CPW pentagonal patch antenna with multiple slots effect for WLAN and WiMAX applications
    (IEEE, 2023)
    Amier Hafizun Ab Rashid
    ;
    Badrul Hisham Ahmad
    ;
    Nornikman Hassan
    ;
    ;
    Mohamad Zoinol Abidin Abd Aziz
    ;
    Nurzaima Mahmod
    This work presents a dual band CPW pentagonal antenna with multiple slots technique for WiMAX and WLAN applications. Antenna A was a basic pentagonal antenna with CPW-fed, while Antenna B was the pentagonal island shaped antenna with CPW. Then it moves on to Antenna C, which has pentagonal island slot with mini pentagonal island slots while Antenna D is the modified version of Antenna C. The objective is to create dual band frequencies with the improvement of the antenna by addition of the multiple slots. The Antenna D has an improvement of - 25.22 dB at 3.5 GHz and - 23.92 dB at 5.92 GHz, making it appropriate for WiMAX and WLAN band, according to the research results.
      13  1
  • Publication
    Characterization of Excimer Laser Micromachining Parameters to Derive Optimal Performance for the Production of Polydimethylsiloxane (PDMS)-based Microfluidic Devices
    Laser micromachining has been used as an alternative to producing microfluidics structures and simplifying the conventional soft lithography process. In this paper we characterize the excimer laser micromachining parameters and demonstrate its application by producing several microfluidic structures in polydimethylsiloxane (PDMS). The parameters include the number of laser pulses, laser energy and rectangular variable aperture (RVA) in both x- and y-directions. We found that the laser energy and pulse rate affect the depth of micromachining d channels, while RVA in both x- and y-directions affects the width of the channels. Repetition of laser scan does not change the channel width but significantly changes the channel depth. Proper adjustment for laser energy and pulse rate is required to fabricate a desired channels depth. In order to demonstrate the microfabrication capability of an excimer laser with the optimal operating parameters, several microfluidic structures were micromachining d into PDMS with a KrF excimer laser.
      1
  • Publication
    Modelling and Simulation using Finite Element Method of Surface Acoustic Wave Biosensor for Gas Detection Application
    A surface acoustic wave (SAW) sensor detects changes in physical properties such as mass and density on its surface. Compared to other types of sensors, SAW sensor have a good stability, high selectivity and sensitivity, fast response, and low-cost. On the other hand, to design and optimize a SAW biosensor requires a long process including time and cost using conventional methods. Therefore, numerical simulation and computational modelling are useful and efficiently conduct analysis for the SAW biosensor. In this paper, a numerical simulation technique is used to analyse the SAW device sensitivity for the application of gas detection. The SAW biosensor can detect very small mass loading by changing its sensor resonance frequency. The two-dimensional (2D) device model is based on a two-port SAW resonator with a gas sensing layer. We made two design of SAW biosensor device with frequency of 872 MHz and 1.74 GHz. A gas with vary concentration from 1 to 100 ppm were used to determine the change of the device resonance frequency. As a result, the high frequency (1.74 GHz) device, shows that the resonance frequency is shifted larger than to the low frequency (872 MHz) device. In addition, the high frequency device offers five times more sensitivity than the low frequency device. By changing the sensor design, the sensor characteristics such as sensitivity can be altered to meet certain sensing requirements. Numerical simulation provides advantages for sensor optimization and useful for nearly representing the real condition.
      5  35