Displaying publications 1 - 20 of 222 in total

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  1. Penyelesaian Kamiran Nyata Berbentuk Kamiran Feynman bagi Persamaan Resapan Teritlak Berpotensi Ayunan Harmonik (Exact Real Integral Solution in the Feynmann Integral Form fora Generalized Diffusion Equation with an Harmonic Potential)
    Shaharir bin Mohamad Zain, Zainal bin Abdul Aziz
    Sains Malaysiana, 1996;25.
    For the generalised diffusion equation with the potential of an harmonic ascillator, we obtain the exact real integral solution in a form similar to the existing Feynman integral solution.
    Penyelesaian tepat berkamiran nyata diperoleh dalam bentuk yang serupa dengan penyelesaian kamiran Feynman yang sedia ada, bagi persamaan resapan teritlak berpotensi pengayun harmonik
    Matched MeSH terms: Diffusion
  2. Analytical solution for Cauchy reaction-diffusion problems by homotopy perturbation method
    Chowdhury M, Hashim I
    Sains Malaysiana, 2010;39.
    In this paper, the homotopy-perturbation method (HPM) is applied to obtain approximate analytical solutions for the Cauchy reaction-diffusion problems. HPM yields solutions in convergent series forms with easily computable terms. The HPM is tested for several examples. Comparisons of the results obtained by the HPM with that obtained by the Adomian decomposition method (ADM), homotopy analysis method (HAM) and the exact solutions show the efficiency of HPM.
    Matched MeSH terms: Diffusion
  3. Fulltext Neuro-genetic optimization of the diffuser elements for applications in a valveless diaphragm micropumps system
    Lee HW, Azid IH
    Sensors (Basel), 2009;9(9):7481-97.
    PMID: 22400004 DOI: 10.3390/s90907481
    In this study, a hybridized neuro-genetic optimization methodology realized by embedding numerical simulations trained artificial neural networks (ANN) into a genetic algorithm (GA) is used to optimize the flow rectification efficiency of the diffuser element for a valveless diaphragm micropump application. A higher efficiency ratio of the diffuser element consequently yields a higher flow rate for the micropump. For that purpose, optimization of the diffuser element is essential to determine the maximum pumping rate that the micropump is able to generate. Numerical simulations are initially carried out using CoventorWare® to analyze the effects of varying parameters such as diffuser angle, Reynolds number and aspect ratio on the volumetric flow rate of the micropump. A limited range of simulation results will then be used to train the neural network via back-propagation algorithm and optimization process commence subsequently by embedding the trained ANN results as a fitness function into GA. The objective of the optimization is to maximize the efficiency ratio of the diffuser element for the range of parameters investigated. The optimized efficiency ratio obtained from the neuro-genetic optimization is 1.38, which is higher than any of the maximum efficiency ratio attained from the overall parametric studies, establishing the superiority of the optimization method.
    Matched MeSH terms: Diffusion
  4. Fulltext An image encryption scheme based on public key cryptosystem and quantum logistic map
    Ye G, Jiao K, Huang X, Goi BM, Yap WS
    Sci Rep, 2020 Dec 03;10(1):21044.
    PMID: 33273539 DOI: 10.1038/s41598-020-78127-2
    Most of existing image encryption schemes are proposed in the spatial domain which easily destroys the correlation between pixels. This paper proposes an image encryption scheme by employing discrete cosine transform (DCT), quantum logistic map and substitution-permutation network (SPN). The DCT is used to transform the images in the frequency domain. Meanwhile, the SPN is used to provide the security properties of confusion and diffusion. The SPN provides fast encryption as compared to the asymmetric based image encryption since operations with low computational complexity are used (e.g., exclusive-or and permutation). Different statistical experiments and security analysis are performed against six grayscale and color images to justify the effectiveness and security of the proposed image encryption scheme.
    Matched MeSH terms: Diffusion
  5. Fulltext Non-Linearity in Wide Dynamic Range CMOS Image Sensors Utilizing a Partial Charge Transfer Technique
    Shafie S, Kawahito S, Halin IA, Hasan WZ
    Sensors (Basel), 2009;9(12):9452-67.
    PMID: 22303133 DOI: 10.3390/s91209452
    The partial charge transfer technique can expand the dynamic range of a CMOS image sensor by synthesizing two types of signal, namely the long and short accumulation time signals. However the short accumulation time signal obtained from partial transfer operation suffers of non-linearity with respect to the incident light. In this paper, an analysis of the non-linearity in partial charge transfer technique has been carried, and the relationship between dynamic range and the non-linearity is studied. The results show that the non-linearity is caused by two factors, namely the current diffusion, which has an exponential relation with the potential barrier, and the initial condition of photodiodes in which it shows that the error in the high illumination region increases as the ratio of the long to the short accumulation time raises. Moreover, the increment of the saturation level of photodiodes also increases the error in the high illumination region.
    Matched MeSH terms: Diffusion
  6. Homotopy decomposition method for solving higher-order time-fractional diffusion equation via modified beta derivative
    Salah Abuasad, Ishak Hashim
    Sains Malaysiana, 2018;47:2899-2905.
    In this paper, the homotopy decomposition method with a modified definition of beta fractional derivative is adopted
    to find approximate solutions of higher-dimensional time-fractional diffusion equations. To apply this method, we find
    the modified beta integral for both sides of a fractional differential equation first, then using homotopy decomposition
    method we can obtain the solution of the integral equation in a series form. We compare the solutions obtained by the
    proposed method with the exact solutions obtained using fractional variational homotopy perturbation iteration method
    via modified Riemann-Liouville derivative. The comparison shows that the results are in a good agreement.
    Matched MeSH terms: Diffusion
  7. Health information systems adoption: findings from a systematic review
    Yusof MM, Stergioulas L, Zugic J
    Stud Health Technol Inform, 2007;129(Pt 1):262-6.
    PMID: 17911719
    Earlier evaluation studies on Health Information Systems (HIS) adoption have highlighted a large number of adoption problems that were attributed to the lack of fit between technology, human and organisation factors. Lessons can be learned from these evaluation studies by identifying the most important factors of HIS adoption. In order to study the adoption issue, a qualitative systematic review has been performed using a recently introduced framework, known as HOT-fit (Human, Organisation and Technology fit). The paper identifies and highlights the following critical adoption factors: technology (ease of use, system usefulness, system flexibility, time efficiency, information accessibility and relevancy); human (user training, user perception, user roles, user skills, clarity of system purpose, user involvement); organisation (leadership and support, clinical process, user involvement, internal communication, inter organisational system, as well as the fit between them. The findings can be used to guide future system development and inform relevant decision making.
    Matched MeSH terms: Diffusion of Innovation*
  8. Making evidence more wanted: a systematic review of facilitators to enhance the uptake of evidence from systematic reviews and meta-analyses
    Wallace J, Byrne C, Clarke M
    Int J Evid Based Healthc, 2012 Dec;10(4):338-46.
    PMID: 23173658 DOI: 10.1111/j.1744-1609.2012.00288.x
    The increased uptake of evidence from systematic reviews is advocated because of their potential to improve the quality of decision making for patient care. Systematic reviews can do this by decreasing inappropriate clinical variation and quickly expediting the application of current, effective advances to everyday practice. However, research suggests that evidence from systematic reviews has not been widely adopted by health professionals. Little is known about the facilitators to uptake of research evidence from systematic reviews and meta-analyses.
    Matched MeSH terms: Diffusion of Innovation*
  9. Microstructural Integrity of Peripheral Nerves in Charcot-Marie-Tooth Disease: An MRI Evaluation Study
    Cheah PL, Krisnan T, Wong JHD, Rozalli FI, Fadzli F, Rahmat K, et al.
    J Magn Reson Imaging, 2021 02;53(2):437-444.
    PMID: 32918328 DOI: 10.1002/jmri.27354
    BACKGROUND: Charcot-Marie-Tooth (CMT) disease is diagnosed through clinical findings and genetic testing. While there are neurophysiological tools and clinical functional scales in CMT, objective disease biomarkers that can facilitate in monitoring disease progression are limited.

    PURPOSE: To investigate the utility of diffusion tensor imaging (DTI) in determining the microstructural integrity of sciatic and peroneal nerves and its correlation with the MRI grading of muscle atrophy severity and clinical function in CMT as determined by the CMT neuropathy score (CMTNS).

    STUDY TYPE: Prospective case-control.

    SUBJECTS: Nine CMT patients and nine age-matched controls.

    FIELD STRENGTH/SEQUENCE: 3 T T1 -weighted in-/out-of phase spoiled gradient recalled echo (SPGR) and DTI sequences.

    ASSESSMENT: Fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (MD) values for sciatic and peroneal nerves were obtained from DTI. Muscle atrophy was graded according to the Goutallier classification using in-/out-of phase SPGRs. DTI parameters and muscle atrophy grades were compared between CMT and controls, and the relationship between DTI parameters, muscle atrophy grades, and CMTNS were assessed.

    STATISTICAL TESTS: The Wilcoxon Signed Ranks test was used to compare DTI parameters between CMT and controls. The relationship between DTI parameters, muscle atrophy grades, and CMTNS were analyzed using the Spearman correlation. Receiver operating characteristic (ROC) analyses of DTI parameters that can differentiate CMT from healthy controls were done.

    RESULTS: There was a significant reduction in FA and increase in RD of both nerves (P 

    Matched MeSH terms: Diffusion Tensor Imaging*
  10. Solid-state self-healing systems: the diffusion of healing agent for healing recovery
    Md Jamil M, Jones F, Muhamad N, Makenan S
    Sains Malaysiana, 2015;44:843-852.
    A clear understanding on the fundamental mechanism in solid state self-healing resin system might significantly improve the optimization of healing performance. The focus of this study was to prove the diffusion (through thermal inter-diffusion) of a linear healing agent within the network matrix resin. The results had demonstrated that 45 to 21 percentage recoveries in fracture toughness (K1C) were observed within the third healing cycles of the healable resin. Based on the optical microscopy, scanning electron microscopy (SEM) and time-of-flight secondary ion mass spectrometry (ToF-SIM) analyst; the diffusion of healing agent was also demonstrated by the change in the morphology and chemical images of the healing agent on the fracture surface specimen, before and after healing process.
    Matched MeSH terms: Diffusion; Thermal Diffusion
  11. Fulltext Central pontine and extrapontine myelinolysis: Diffusion weighted imaging and diffusion tensor imaging on follow-up
    Nair SR, Ramli NM, Rahmat K, Mei-Ling ST
    Neurol India, 2012 Jul-Aug;60(4):426-8.
    PMID: 22954982 DOI: 10.4103/0028-3886.100712
    Matched MeSH terms: Diffusion Magnetic Resonance Imaging; Diffusion Tensor Imaging*
  12. An overview of the national telehealth initiative in Malaysia
    Maon SN, Edirippulige S
    Stud Health Technol Inform, 2010;161:95-103.
    PMID: 21191162
    Malaysia's national health statistics for the last half century show a remarkable improvement in the nation's health status. One important factor for this improvement is the Malaysian government's proactive intervention in the health sector. Among others, e-health has played a vital role in delivering and managing healthcare services in Malaysia. While the Government has integrated telehealth in its national digital infrastructure re-design, it has heavily invested in telehealth. The enactment of new laws to facilitate telehealth practices can also be noted as an important measure.
    Matched MeSH terms: Diffusion of Innovation*
  13. Fulltext Diffusion weighted MR imaging in acute vertebral compression fractures: differentiation between malignant and benign causes
    Bhugaloo A, Abdullah B, Siow Y, Ng Kh
    Biomed Imaging Interv J, 2006 Apr;2(2):e12.
    PMID: 21614224 MyJurnal DOI: 10.2349/biij.2.2.e12
    The primary objective of this study was to evaluate the specificity and sensitivity of diffusion weighted MR imaging (DWI) in the differentiation and characterisation between benign and malignant vertebral compression fractures compared with conventional T1 WI, T2 WI and fat suppressed contrast enhanced T1 WI in the Malaysian population.
    Matched MeSH terms: Diffusion Magnetic Resonance Imaging
  14. Fulltext Health innovation for patient safety improvement
    Sellappans R, Chua SS, Tajuddin NA, Lai PSM
    Australas Med J, 2013;6(1):60-3.
    PMID: 23423150 DOI: 10.4066/AMJ.2013.1643
    Medication error has been identified as a major factor affecting patient safety. Many innovative efforts such as Computerised Physician Order Entry (CPOE), a Pharmacy Information System, automated dispensing machines and Point of Administration Systems have been carried out with the aim of improving medication safety. However, areas remain that require urgent attention. One main area will be the lack of continuity of care due to the breakdown of communication between multiple healthcare providers. Solutions may include consideration of "health smart cards" that carry vital patient medical information in the form of a "credit card" or use of the Malaysian identification card. However, costs and technical aspects associated with the implementation of this health smart card will be a significant barrier. Security and confidentiality, on the other hand, are expected to be of primary concern to patients. Challenges associated with the implementation of a health smart card might include physician buy-in for use in his or her everyday practice. Training and technical support should also be available to ensure the smooth implementation of this system. Despite these challenges, implementation of a health smart card moves us closer to seamless care in our country, thereby increasing the productivity and quality of healthcare.
    Matched MeSH terms: Diffusion of Innovation
  15. Fulltext Non-alignment stagnation-point flow of a nanofluid past a permeable stretching/shrinking sheet: Buongiorno's model
    Hamid RA, Nazar R, Pop I
    Sci Rep, 2015;5:14640.
    PMID: 26440761 DOI: 10.1038/srep14640
    The paper deals with a stagnation-point boundary layer flow towards a permeable stretching/shrinking sheet in a nanofluid where the flow and the sheet are not aligned. We used the Buongiorno model that is based on the Brownian diffusion and thermophoresis to describe the nanofluid in this problem. The main purpose of the present paper is to examine whether the non-alignment function has the effect on the problem considered when the fluid suction and injection are imposed. It is interesting to note that the non-alignment function can ruin the symmetry of the flows and prominent in the shrinking sheet. The fluid suction will reduce the impact of the non-alignment function of the stagnation flow and the stretching/shrinking sheet but at the same time increasing the velocity profiles and the shear stress at the surface. Furthermore, the effects of the pertinent parameters such as the Brownian motion, thermophoresis, Lewis number and the suction/injection on the flow and heat transfer characteristics are also taken into consideration. The numerical results are shown in the tables and the figures. It is worth mentioning that dual solutions are found to exist for the shrinking sheet.
    Matched MeSH terms: Diffusion
  16. Fulltext High Accuracy Spline Explicit Group (SEG) Approximation for Two Dimensional Elliptic Boundary Value Problems
    Goh J, Hj M Ali N
    PLoS One, 2015;10(7):e0132782.
    PMID: 26182211 DOI: 10.1371/journal.pone.0132782
    Over the last few decades, cubic splines have been widely used to approximate differential equations due to their ability to produce highly accurate solutions. In this paper, the numerical solution of a two-dimensional elliptic partial differential equation is treated by a specific cubic spline approximation in the x-direction and finite difference in the y-direction. A four point explicit group (EG) iterative scheme with an acceleration tool is then applied to the obtained system. The formulation and implementation of the method for solving physical problems are presented in detail. The complexity of computational is also discussed and the comparative results are tabulated to illustrate the efficiency of the proposed method.
    Matched MeSH terms: Diffusion
  17. Fulltext Some numerical methods and comparisons for solving mathematical model of surface decontamination by disinfectant solution
    Chai, Jin Sian, Hoe, Yeak Su, Ali H. M. Murid
    MATEMATIKA, 2018;34(2):0-0.
    MyJurnal
    A mathematical model is considered to determine the effectiveness of disin-
    fectant solution for surface decontamination. The decontamination process involved the
    diffusion of bacteria into disinfectant solution and the reaction of the disinfectant killing
    effect. The mathematical model is a reaction-diffusion type. Finite difference method and
    method of lines with fourth-order Runge-Kutta method are utilized to solve the model
    numerically. To obtain stable solutions, von Neumann stability analysis is employed to
    evaluate the stability of finite difference method. For stiff problem, Dormand-Prince
    method is applied as the estimated error of fourth-order Runge-Kutta method. MATLAB
    programming is selected for the computation of numerical solutions. From the results
    obtained, fourth-order Runge-Kutta method has a larger stability region and better ac-
    curacy of solutions compared to finite difference method when solving the disinfectant
    solution model. Moreover, a numerical simulation is carried out to investigate the effect
    of different thickness of disinfectant solution on bacteria reduction. Results show that
    thick disinfectant solution is able to reduce the dimensionless bacteria concentration more
    effectively.
    Matched MeSH terms: Diffusion
  18. Fulltext On solution existence of MHD Casson nanofluid transportation across an extending cylinder through porous media and evaluation of priori bounds
    Abdal S, Hussain S, Siddique I, Ahmadian A, Ferrara M
    Sci Rep, 2021 Apr 08;11(1):7799.
    PMID: 33833251 DOI: 10.1038/s41598-021-86953-1
    It is a theoretical exportation for mass transpiration and thermal transportation of Casson nanofluid over an extending cylindrical surface. The Stagnation point flow through porous matrix is influenced by magnetic field of uniform strength. Appropriate similarity functions are availed to yield the transmuted system of leading differential equations. Existence for the solution of momentum equation is proved for various values of Casson parameter [Formula: see text], magnetic parameter M, porosity parameter [Formula: see text] and Reynolds number Re in two situations of mass transpiration (suction/injuction). The core interest for this study aroused to address some analytical aspects. Therefore, existence of solution is proved and uniqueness of this results is discussed with evaluation of bounds for existence of solution. Results for skin friction factor are established to attain accuracy for large injection values. Thermal and concentration profiles are delineated numerically by applying Runge-Kutta method and shooting technique. The flow speed retards against M, [Formula: see text] and [Formula: see text] for both situations of mass injection and suction. The thermal boundary layer improves with Brownian and thermopherotic diffusions.
    Matched MeSH terms: Diffusion
  19. Fulltext Reaction-Multi Diffusion Model for Nutrient Release and Autocatalytic Degradation of PLA-Coated Controlled-Release Fertilizer
    Irfan SA, Razali R, KuShaari K, Mansor N
    Polymers (Basel), 2017 Mar 22;9(3).
    PMID: 30970794 DOI: 10.3390/polym9030111
    A mathematical model for the reaction-diffusion equation is developed to describe the nutrient release profiles and degradation of poly(lactic acid) (PLA)-coated controlled-release fertilizer. A multi-diffusion model that consists of coupled partial differential equations is used to study the diffusion and chemical reaction (autocatalytic degradation) simultaneously. The model is solved using an analytical-numerical method. Firstly, the model equation is transformed using the Laplace transformation as the Laplace transform cannot be inverted analytically. Numerical inversion of the Laplace transform is used by employing the Zakian method. The solution is useful in predicting the nutrient release profiles at various diffusivity, concentration of extraction medium, and reaction rates. It also helps in explaining the transformation of autocatalytic concentration in the coating material for various reaction rates, times of reaction, and reaction-multi diffusion. The solution is also applicable to the other biodegradable polymer-coated controlled-release fertilizers.
    Matched MeSH terms: Diffusion
  20. A Comparative Study of Transmembrane Diffusion and Permeation of Ibuprofen across Synthetic Membranes Using Franz Diffusion Cells
    Ng SF, Rouse J, Sanderson D, Eccleston G
    Pharmaceutics, 2010 May 18;2(2):209-223.
    PMID: 27721352
    Synthetic membranes used in Franz diffusion cells for topical formulation quality assessment should provide least resistance to drug diffusion. In this study, the diffusion rates of ibuprofen across thirteen membranes were determined using Franz diffusion cells. Correlation of the membrane thickness, pore size and MWCO with drug fluxes was also made. The drug diffusion results showed that the porous membranes were categorized into high-flux (8-18 mg/cm²/h) and low-flux (0.1-3 mg/cm²/h) membranes. The drug fluxes did not show strong correlations (r² < 0.99) with membrane parameters. Synthetic membranes can give variable drug fluxes, thus investigators should be careful in choosing membrane for formulation quality assessment.
    Matched MeSH terms: Diffusion
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