Displaying publications 1 - 20 of 113 in total

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  1. Correction to: The versatile role of exosomes in cancer progression: diagnostic and therapeutic implications
    Sundararajan V, Sarkar FH, Ramasamy TS
    Cell Oncol (Dordr), 2018 08;41(4):463.
    PMID: 30047093 DOI: 10.1007/s13402-018-0396-2
    In the title of above mentioned article the word 'versatile' had been replaced by 'multifaceted'.
    Matched MeSH terms: Rotation
  2. Fulltext Density Functional Theory Studies of the Electronic Structure and Muon Hyperfine Interaction in [Au25(SR)18]0 and [Au25(SeR)18]0 Nanoclusters
    Ahmad SN, Zaharim WN, Sulaiman S, Hasan Baseri DF, Mohd Rosli NA, Ang LS, et al.
    ACS Omega, 2020 Dec 29;5(51):33253-33261.
    PMID: 33403287 DOI: 10.1021/acsomega.0c04937
    Density functional theory computational investigation was performed to study the electronic structures, muon sites, and the associated hyperfine interactions in [Au25(SR)18]0 and [Au25(SeR)18]0 where R is phenylethane. The calculated electronic structures show inhomogeneous spin density distribution and are also affected by different ligands. The two most stable muon sites near Au atoms in the thiolated system are MAu11 and MAu6. When the thiolate ligands were replaced by selenolate ligands, the lowest energy positions of muons moved to MAu6 and MAu5. Muons prefer to stop inside the Au12 icosahedral shell, away from the central Au and the staple motifs region. Muonium states at phenyl ring and S/Se atoms in the ligand were found to be stable and the Fermi contact fields are much larger as compared to the field experienced by muons near Au atoms.
    Matched MeSH terms: Rotation
  3. Fulltext On parameter estimation of a replicated linear functional relationship model for circular variables
    Nurkhairany Amyra Mokhtar, Yong Zulina Zubairi, Abdul Ghapor Hussin, Rossita Mohamad Yunus
    MATEMATIKA, 2017;33(2):159-163.
    MyJurnal
    Replicated linear functional relationship model is often used to describe
    relationships between two circular variables where both variables have error terms and
    replicate observations are available. We derive the estimate of the rotation parameter
    of the model using the maximum likelihood method. The performance of the proposed
    method is studied through simulation, and it is found that the biasness of the estimates
    is small, thus implying the suitability of the method. Practical application of the
    method is illustrated by using a real data set.
    Matched MeSH terms: Rotation
  4. Formation and sustainability of h-mode regime in tokamak plasma via source perturbations based on two-field bifurcation concept
    Onjun T, Chatthong .
    Sains Malaysiana, 2017;46:1385-1392.
    A set of coupled particle and thermal transport equations is used to study a formation and sustainability of an edge transport barrier (ETB) in tokamak plasmas based on two-field bifurcation. The two transport equations are numerically solved for spatio-temporal profiles of plasma pressure and density. The plasma core transport includes both neoclassical and turbulent effects, where the latter can be suppressed by flow shear mechanism. The flow shear, approximated from the force balance equation, is proportional to the product of pressure and density gradients, resulting in non-linearity behaviors in this calculation. The main thermal and particle sources are assumed to be localized near plasma center and edge, respectively. It is found that the fluxes versus gradients regime illustrates bifurcation nature of the plasma. This picture of the plasma implies hysteresis properties in fluxes versus gradients space. Hence, near marginal point, the perturbation in thermal or particle sources can trigger an L-H transition. Due to hysteresis, the triggered H-mode can be sustained and the central plasma pressure and density can be enhanced.
    Matched MeSH terms: Rotation
  5. Fulltext Mechanics Model for Simulating RC Hinges under Reversed Cyclic Loading
    Shukri AA, Visintin P, Oehlers DJ, Jumaat MZ
    Materials (Basel), 2016 Apr 22;9(4).
    PMID: 28773430 DOI: 10.3390/ma9040305
    Describing the moment rotation (M/θ) behavior of reinforced concrete (RC) hinges is essential in predicting the behavior of RC structures under severe loadings, such as under cyclic earthquake motions and blast loading. The behavior of RC hinges is defined by localized slip or partial interaction (PI) behaviors in both the tension and compression region. In the tension region, slip between the reinforcement and the concrete defines crack spacing, crack opening and closing, and tension stiffening. While in the compression region, slip along concrete to concrete interfaces defines the formation and failure of concrete softening wedges. Being strain-based, commonly-applied analysis techniques, such as the moment curvature approach, cannot directly simulate these PI behaviors because they are localized and displacement based. Therefore, strain-based approaches must resort to empirical factors to define behaviors, such as tension stiffening and concrete softening hinge lengths. In this paper, a displacement-based segmental moment rotation approach, which directly simulates the partial interaction behaviors in both compression and tension, is developed for predicting the M/θ response of an RC beam hinge under cyclic loading. Significantly, in order to develop the segmental approach, a partial interaction model to predict the tension stiffening load slip relationship between the reinforcement and the concrete is developed.
    Matched MeSH terms: Rotation
  6. Fulltext Distinctive accuracy measurement of binary descriptors in mobile augmented reality
    Tan SY, Arshad H, Abdullah A
    PLoS One, 2019;14(1):e0207191.
    PMID: 30605474 DOI: 10.1371/journal.pone.0207191
    Mobile Augmented Reality (MAR) requires a descriptor that is robust to changes in viewing conditions in real time application. Many different descriptors had been proposed in the literature for example floating-point descriptors (SIFT and SURF) and binary descriptors (BRIEF, ORB, BRISK and FREAK). According to literature, floating-point descriptors are not suitable for real-time application because its operating speed does not satisfy real-time constraints. Binary descriptors have been developed with compact sizes and lower computation requirements. However, it is unclear which binary descriptors are more appropriate for MAR. Hence, a distinctive and efficient accuracy measurement of four state-of-the-art binary descriptors, namely, BRIEF, ORB, BRISK and FREAK were performed using the Mikolajczyk dataset and ALOI dataset to identify the most appropriate descriptor for MAR in terms of computation time and robustness to brightness, scale and rotation changes. The obtained results showed that FREAK is the most appropriate descriptor for MAR application as it able to produce an application that are efficient (shortest computation time) and robust towards scale, rotation and brightness changes.
    Matched MeSH terms: Rotation
  7. Fulltext Wind shear data at two different terrain types
    Albani A, Ibrahim MZ, Yong KH
    Data Brief, 2019 Aug;25:104306.
    PMID: 31406911 DOI: 10.1016/j.dib.2019.104306
    The measurement of this data aims to evaluate the wind shear variability at three selected sites in Malaysia. The sites are Kudat in Sabah, Kijal in Terengganu and Langkawi in Kedah. Both sites in Kudat and Kijal is located in coastal areas with few buildings or trees, while the site in Langkawi is a coastal area with many buildings or trees. The variables were measured using the sensors that mounted on the wind mast with the maximum height from 55 m to 70 m from ground level. The variables measured were wind speed, wind direction, temperature, and pressure, while the wind shear data were directly generated using the power law equation. The averaged wind shear based on measured multiple height wind speed at selected sites is larger than the 1/7 law (0.143). Also, the value of wind shear was higher in order Langkawi > Kudat > Kijal. Ultimately, the wind shear data are essential and can be reused in the wind energy potential study, especially for data extrapolation to desired wind turbine hub height.
    Matched MeSH terms: Rotation
  8. Fulltext Reference Frame Unification of IMU-Based Joint Angle Estimation: The Experimental Investigation and a Novel Method
    Yi C, Jiang F, Yang C, Chen Z, Ding Z, Liu J
    Sensors (Basel), 2021 Mar 05;21(5).
    PMID: 33807746 DOI: 10.3390/s21051813
    Inertial measurement unit (IMU)-based joint angle estimation is an increasingly mature technique that has a broad range of applications in clinics, biomechanics and robotics. However, the deviations of different IMUs' reference frames, referring to IMUs' individual orientations estimating errors, is still a challenge for improving the angle estimation accuracy due to conceptual confusion, relatively simple metrics and the lack of systematical investigation. In this paper, we clarify the determination of reference frame unification, experimentally study the time-varying characteristics of reference frames' deviations and accordingly propose a novel method with a comprehensive metric to unify reference frames. To be specific, we firstly define the reference frame unification (RFU) and distinguish it with drift correction that has always been confused with the term RFU. Secondly, we design a mechanical gimbal-based experiment to study the deviations, where sensor-to-body alignment and rotation-caused differences of orientations are excluded. Thirdly, based on the findings of the experiment, we propose a novel method to utilize the consistency of the joint axis under the hinge-joint constraint, gravity acceleration and local magnetic field to comprehensively unify reference frames, which meets the nonlinear time-varying characteristics of the deviations. The results on ten human subjects reveal the feasibility of our proposed method and the improvement from previous methods. This work contributes to a relatively new perspective of considering and improving the accuracy of IMU-based joint angle estimation.
    Matched MeSH terms: Rotation
  9. Fulltext Pseudogap and proximity effect in the Bi2Te3/Fe1+yTe interfacial superconductor
    He MQ, Shen JY, Petrović AP, He QL, Liu HC, Zheng Y, et al.
    Sci Rep, 2016 09 02;6:32508.
    PMID: 27587000 DOI: 10.1038/srep32508
    In the interfacial superconductor Bi2Te3/Fe1+yTe, two dimensional superconductivity occurs in direct vicinity to the surface state of a topological insulator. If this state were to become involved in superconductivity, under certain conditions a topological superconducting state could be formed, which is of high interest due to the possibility of creating Majorana fermionic states. We report directional point-contact spectroscopy data on the novel Bi2Te3/Fe1+yTe interfacial superconductor for a Bi2Te3 thickness of 9 quintuple layers, bonded by van der Waals epitaxy to a Fe1+yTe film at an atomically sharp interface. Our data show highly unconventional superconductivity, which appears as complex as in the cuprate high temperature superconductors. A very large superconducting twin-gap structure is replaced by a pseudogap above ~12 K which persists up to 40 K. While the larger gap shows unconventional order parameter symmetry and is attributed to a thin FeTe layer in proximity to the interface, the smaller gap is associated with superconductivity induced via the proximity effect in the topological insulator Bi2Te3.
    Matched MeSH terms: Rotation
  10. Feedback control of thermocapillary convection in a rotating fluid layer with free-slip bottom
    Ishak Hashim, Zailan Siri
    Sains Malaysiana, 2009;38.
    The linear stability theory is applied to investigate the effects of rotation and feedback control on the onset of steady and oscillatory thermocapillary convection in a horizontal fluid layer heated from below with a free-slip bottom. The thresholds and codimension-2 points for the onset of steady and oscillatory convection are determined. The effect of feedback control on the parameter space dividing the steady and oscillatory convection regions is demonstrated.
    Matched MeSH terms: Rotation
  11. Fulltext 1700 nm and 1800 nm band tunable thulium doped mode-locked fiber lasers
    Emami SD, Dashtabi MM, Lee HJ, Arabanian AS, Rashid HAA
    Sci Rep, 2017 Oct 06;7(1):12747.
    PMID: 28986584 DOI: 10.1038/s41598-017-13200-x
    This paper presents short wavelength operation of tunable thulium-doped mode-locked lasers with sweep ranges of 1702 to 1764 nm and 1788 to 1831 nm. This operation is realized by a combination of the partial amplified spontaneous emission suppression method, the bidirectional pumping mechanism and the nonlinear polarization rotation (NPR) technique. Lasing at emission bands lower than the 1800 nm wavelength in thulium-doped fiber lasers is achieved using mode confinement loss in a specially designed photonic crystal fiber (PCF). The enlargement of the first outer ring air holes around the core region of the PCF attenuates emissions above the cut-off wavelength and dominates the active region. This amplified spontaneous emission (ASE) suppression using our presented PCF is applied to a mode-locked laser cavity and is demonstrated to be a simple and compact solution to widely tunable all-fiber lasers.
    Matched MeSH terms: Rotation
  12. Fulltext Modal behaviour of vertical axis Wind Turbine Comprising Prestressed Rotor Blades: A finite element analysis
    Torabi Asr, M., Masoumi, M.M., Mustapha, F.
    Pertanika Journal of Science & Technology, 2017;25(3):977-982.
    MyJurnal
    Pre-stressing is a concept used in many engineering structures. In this study prestressing in the form of axial compression stress is proposed in the blade structure of H-Darrieus wind turbine. The study draws a structural comparison between reference and prestressed configurations of turbine rotor with respect to their dynamic vibrational response. Rotordynamics calculations provided by ANSYS Mechanical is used to investigate the effects of turbine rotation on the dynamic response of the system. Rotation speed ranging between 0 to 150 rad/s was examined to cover the whole operating range of commercial instances. The modal analysis ends up with first six mode shapes of both rotor configurations. As a result, the displacement of the proposed configurations reduced effectively. Apparent variations in Campbell diagrams of both cases indicate that prestressed configuration has its resonant frequencies far away from turbine operation speeds and thus remarkably higher safety factor against whirling and probable following failures.
    Matched MeSH terms: Rotation
  13. SCL: Self-supervised contrastive learning for few-shot image classification
    Lim JY, Lim KM, Lee CP, Tan YX
    Neural Netw, 2023 Aug;165:19-30.
    PMID: 37263089 DOI: 10.1016/j.neunet.2023.05.037
    Few-shot learning aims to train a model with a limited number of base class samples to classify the novel class samples. However, to attain generalization with a limited number of samples is not a trivial task. This paper proposed a novel few-shot learning approach named Self-supervised Contrastive Learning (SCL) that enriched the model representation with multiple self-supervision objectives. Given the base class samples, the model is trained with the base class loss. Subsequently, contrastive-based self-supervision is introduced to minimize the distance between each training sample with their augmented variants to improve the sample discrimination. To recognize the distant sample, rotation-based self-supervision is proposed to enable the model to learn to recognize the rotation degree of the samples for better sample diversity. The multitask environment is introduced where each training sample is assigned with two class labels: base class label and rotation class label. Complex augmentation is put forth to help the model learn a deeper understanding of the object. The image structure of the training samples are augmented independent of the base class information. The proposed SCL is trained to minimize the base class loss, contrastive distance loss, and rotation class loss simultaneously to learn the generic features and improve the novel class performance. With the multiple self-supervision objectives, the proposed SCL outperforms state-of-the-art few-shot approaches on few-shot image classification benchmark datasets.
    Matched MeSH terms: Rotation
  14. Examining the Range of Motion of the Cervical Spine: Utilising Different Bedside Instruments
    Sukari AAA, Singh S, Bohari MH, Idris Z, Ghani ARI, Abdullah JM
    Malays J Med Sci, 2021 Apr;28(2):100-105.
    PMID: 33958964 DOI: 10.21315/mjms2021.28.2.9
    Background: This paper outlines a summary of examination technique to identify the range of movement of the cervical spine. Due to common difficulties in obtaining tools for cervical examination within the district, a standardised compilation of easy-to-replicate examination techniques are provided using different tools.

    Methods: Bedside instruments that can be used includes a measuring tape, compass, goniometer, inclinometer and cervical range of motion (CROM) instrument.

    Discussion: Cervical flexion-extension, lateral flexion and rotation will be assessed with bedside instruments. This would aid in increasing accuracy and precision of objective measurement while conducting clinical examination to determine the cervical range of motion.

    Matched MeSH terms: Rotation
  15. Fulltext Dynamic finite element analysis of mobile bearing type knee prosthesis under deep flexional motion
    Anuar MA, Todo M, Nagamine R, Hirokawa S
    ScientificWorldJournal, 2014;2014:586921.
    PMID: 25133247 DOI: 10.1155/2014/586921
    The primary objective of this study is to distinguish between mobile bearing and fixed bearing posterior stabilized knee prostheses in the mechanics performance using the finite element simulation. Quantifying the relative mechanics attributes and survivorship between the mobile bearing and the fixed bearing prosthesis remains in investigation among researchers. In the present study, 3-dimensional computational model of a clinically used mobile bearing PS type knee prosthesis was utilized to develop a finite element and dynamic simulation model. Combination of displacement and force driven knee motion was adapted to simulate a flexion motion from 0° to 135° with neutral, 10°, and 20° internal tibial rotation to represent deep knee bending. Introduction of the secondary moving articulation in the mobile bearing knee prosthesis has been found to maintain relatively low shear stress during deep knee motion with tibial rotation.
    Matched MeSH terms: Rotation*
  16. A robust real-time gait event detection using wireless gyroscope and its application on normal and altered gaits
    Gouwanda D, Gopalai AA
    Med Eng Phys, 2015 Feb;37(2):219-25.
    PMID: 25619613 DOI: 10.1016/j.medengphy.2014.12.004
    Gait events detection allows clinicians and biomechanics researchers to determine timing of gait events, to estimate duration of stance phase and swing phase and to segment gait data. It also aids biomedical engineers to improve the design of orthoses and FES (functional electrical stimulation) systems. In recent years, researchers have resorted to using gyroscopes to determine heel-strike (HS) and toe-off (TO) events in gait cycles. However, these methods are subjected to significant delays when implemented in real-time gait monitoring devices, orthoses, and FES systems. Therefore, the work presented in this paper proposes a method that addresses these delays, to ensure real-time gait event detection. The proposed algorithm combines the use of heuristics and zero-crossing method to identify HS and TO. Experiments involving: (1) normal walking; (2) walking with knee brace; and (3) walking with ankle brace for overground walking and treadmill walking were designed to verify and validate the identified HS and TO. The performance of the proposed method was compared against the established gait detection algorithms. It was observed that the proposed method produced detection rate that was comparable to earlier reported methods and recorded reduced time delays, at an average of 100 ms.
    Matched MeSH terms: Rotation*
  17. Fulltext The effect of long working hours among medical doctors in northwest Malaysia: the interplay between personality big five inventory and fatigue
    Karniza Khalid, Thyagarajan, Dandaithapani, Muhammad Zul Azri Mohammad Yusof, Ruzita Jamaluddin
    Journal of Occupational Safety and Health, 2019;16(2):1-9.
    MyJurnal
    Medical professionals work in a constantly stressful environment. The nature of the profession requires routine extended working hours, but little is known about the effect of long working hours on selective physiological measures. A cross-sectional feasibility study was conducted from 1 October 2017 until 30 April 2018 on medical doctors in a tertiary health centre in northwest Malaysia. There was a total of 55 study participants recruited. The overall systolic blood pressure (SBP) was highest after working 24-hour stretch (p=0.006) and the overall diastolic blood pressure (DBP) were highest after working for 33 hours in a single stretch, at the end of on call rotation (p
    Matched MeSH terms: Rotation
  18. Absolute Photoabsorption Cross-Sections of Methanol for Terrestrial and Astrophysical Relevance
    Lange E, Lozano AI, Jones NC, Hoffmann SV, Kumar S, Śmiałek MA, et al.
    J Phys Chem A, 2020 Sep 30.
    PMID: 32941031 DOI: 10.1021/acs.jpca.0c06615
    We investigate the methanol absorption spectrum in the range 5.5-10.8 eV to provide accurate and absolute cross-sections values. The main goal of this study is to provide a comprehensive analysis of methanol electronic-state spectroscopy by employing high-resolution vacuum ultraviolet (VUV) photoabsorption measurements together with state-of-the-art quantum chemical calculation methods. The VUV spectrum reveals several new features that are not previously reported in literature, for n > 3 in the transitions (nsσ(a') ← (2a″)) (1A' ← X̃1A') and (nsσ, npσ, npσ', ndσ ← (7a')) (1A' ← X̃1A'), and with particular relevance to vibrational progressions of the CH3 rocking mode, v11'(a″), mode in the (3pπ(a″) ← (2a″)) (21A' ← X̃1A') absorption band at 8.318 eV. The measured absolute photoabsorption cross-sections have subsequently been used to calculate the photolysis lifetime of methanol in the Earth's atmosphere from the ground level up to the limit of the stratosphere (50 km altitude). This shows that solar photolysis plays a negligible role in the removal of methanol from the lower atmosphere compared with competing sink mechanisms. Torsional potential energy scans, as a function of the internal rotation angle for the ground and first Rydberg states, have also been calculated as part of this investigation.
    Matched MeSH terms: Rotation
  19. Fulltext The non-Newtonian maxwell nanofluid flow between two parallel rotating disks under the effects of magnetic field
    Ahmadian A, Bilal M, Khan MA, Asjad MI
    Sci Rep, 2020 Oct 13;10(1):17088.
    PMID: 33051520 DOI: 10.1038/s41598-020-74096-8
    The main feature of the present numerical model is to explore the behavior of Maxwell nanoliquid moving within two horizontal rotating disks. The disks are stretchable and subjected to a magnetic field in axial direction. The time dependent characteristics of thermal conductivity have been considered to scrutinize the heat transfer phenomena. The thermophoresis and Brownian motion features of nanoliquid are studied with Buongiorno model. The lower and upper disk's rotation for both the cases, same direction as well as opposite direction of rotation is investigated. The subsequent arrangement of the three dimensional Navier Stoke's equations along with energy, mass and Maxwell equations are diminished to a dimensionless system of equations through the Von Karman's similarity framework. The comparative numerical arrangement of modeled equations is further set up by built-in numerical scheme "boundary value solver" (Bvp4c) and Runge Kutta fourth order method (RK4). The various physical constraints, such as Prandtl number, thermal conductivity, magnetic field, thermal radiation, time relaxation, Brownian motion and thermophoresis parameters and their impact are presented and discussed briefly for velocity, temperature, concentration and magnetic strength profiles. In the present analysis, some vital characteristics such as Nusselt and Sherwood numbers are considered for physical and numerical investigation. The outcomes concluded that the disk stretching action opposing the flow behavior. With the increases of magnetic field parameter [Formula: see text] the fluid velocity decreases, while improving its temperature. We show a good agreement of the present work by comparing with those published in literature.
    Matched MeSH terms: Rotation
  20. Fulltext 3D Transparent Object Detection and Reconstruction Based on Passive Mode Single-Pixel Imaging
    Mathai A, Guo N, Liu D, Wang X
    Sensors (Basel), 2020 Jul 29;20(15).
    PMID: 32751165 DOI: 10.3390/s20154211
    Transparent object detection and reconstruction are significant, due to their practical applications. The appearance and characteristics of light in these objects make reconstruction methods tailored for Lambertian surfaces fail disgracefully. In this paper, we introduce a fixed multi-viewpoint approach to ascertain the shape of transparent objects, thereby avoiding the rotation or movement of the object during imaging. In addition, a simple and cost-effective experimental setup is presented, which employs two single-pixel detectors and a digital micromirror device, for imaging transparent objects by projecting binary patterns. In the system setup, a dark framework is implemented around the object, to create shades at the boundaries of the object. By triangulating the light path from the object, the surface shape is recovered, neither considering the reflections nor the number of refractions. It can, therefore, handle transparent objects with a relatively complex shape with the unknown refractive index. The implementation of compressive sensing in this technique further simplifies the acquisition process, by reducing the number of measurements. The experimental results show that 2D images obtained from the single-pixel detectors are better in quality with a resolution of 32×32. Additionally, the obtained disparity and error map indicate the feasibility and accuracy of the proposed method. This work provides a new insight into 3D transparent object detection and reconstruction, based on single-pixel imaging at an affordable cost, with the implementation of a few numbers of detectors.
    Matched MeSH terms: Rotation
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