Displaying all 16 publications

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  1. Roslan R, Saleh H, Hashim I
    ScientificWorldJournal, 2014;2014:617492.
    PMID: 24991643 DOI: 10.1155/2014/617492
    The aim of the present numerical study is to analyze the conjugate natural convection heat transfer in a differentially heated square enclosure containing a conductive polygon object. The left wall is heated and the right wall is cooled, while the horizontal walls are kept adiabatic. The COMSOL Multiphysics software is applied to solve the dimensionless governing equations. The governing parameters considered are the polygon type, 3 ≤ N ≤ ∞, the horizontal position, 0.25 ≤ X 0 ≤ 0.75, the polygon size, 0 ≤ A ≤ π/16, the thermal conductivity ratio, 0.1 ≤ K r ≤ 10.0, and the Rayleigh number, 10(3) ≤ Ra ≤ 10(6). The critical size of the solid polygon was found exists at low conductivities. The heat transfer rate increases with the increase of the size of the solid polygon, until it reaches its maximum value. Here, the size of the solid polygon is reaches its critical value. Further, beyond this critical size of the solid polygon, will decrease the heat transfer rate.
  2. Harlina H Siraj, Salam A, Roslan R, Hasan NA, Jin TH, Othman MN
    MyJurnal
    Introduction: Student can be stressed due to different stressors such as academic, financial, health related or loss of close family member or friend, etc. Stress is the bodies’ reaction both neurologically and physiologically to adapt to the new condition. Stress has a negative effect on the academic performance of the students. This study was aimed to explore the stress and stressors and also to determine the association between stress levels and the academic performances in terms of cumulative grade point average (CGPA) of undergraduate medical students. Methods: It was a cross-sectional study conducted among all 234 year-4 medical students of Universiti Kebangsaan Malaysia (UKM), session 2011-2012. Sample size comprised of 179 students after fulfilling all inclusion and exclusion criteria. A validated Medical Students’ Stressor Questionnaire (MSSQ) was used to collect the data. Stress level and its association with CGPA of semester-1 examination were analysed. Results: Response rate was 76.49%, where 72% were female and 69% resided in the hostel. Academic Related and Social-related Stressors caused for severe and high stress in 84% and 49% respondents respectively, with insignificant differences between gender and residency. Respondents with a high and severe stress level were observed to have higher CGPA. Conclusion: UKM medical students are highly resourceful to manage their stress well and thus denying the negative effect of stress towards their academic performance. Medical schools should train students exposing various personal and professional developmental activities that able to face the everyday challenges and manage stress well and thereby achieve better academic performance.
  3. Madaki AG, Abdulhameed M, Ali M, Roslan R
    Springerplus, 2016;5:513.
    PMID: 27186477 DOI: 10.1186/s40064-016-2147-z
    In this paper, a revised optimal homotopy asymptotic method (OHAM) is applied to derive an explicit analytical solution of the Falkner-Skan wedge flow problem. The comparisons between the present study with the numerical solutions using (fourth order Runge-Kutta) scheme and with analytical solution using HPM-Padé of order [4/4] and order [13/13] show that the revised form of OHAM is an extremely effective analytical technique.
  4. Supandi FN, Singh B, Roslan R, Husin I, Lee TS
    Ann Hepatobiliary Pancreat Surg, 2021 Jun 30;25(Suppl 1):S240.
    PMID: 34230345 DOI: 10.14701/ahbps.EP-39
    Introduction: The rarity of caudate lobe abscess has made it difficult to outline a treatment algorithm for this pathology due to its anatomically challenging site. Caudate lobe abscesses also poses a risk of rupture, making its management more complicated. However, advances in imaging have made it possible for early detection and paradigm shift in its management from open surgery to non-operative intervention.

    Methods: All patients with isolated caudate lobe abscess were selected retrospectively and diagnosis was confirmed by imaging. Patient in this case series underwent either percutaneous or endoscopic drainage and empirical antibiotic therapy alone.

    Results: There are 5 patients in this case series, 3 of them underwent percutaneous drainage, 1 of them treated with antibiotic alone and another underwent endoscopic ultrasound (EUS)-guided drainage. All patients showed complete resolution of caudate lobe abscess without procedural complications.

    Conclusions: The caudate lobe, which lies posterior to the hepatoduodenal ligament and anterior to the inferior vena cava exposes the patient to possible life-threatening complications when subjected to drainage via a percutaneous approach. EUS allows not only identification of intervening vessels which is the major reason for technical difficulty in percutaneous drainage, but excellent visualization of abscess cavities and the surrounding landmarks. In conclusion, non-surgical approach is our treatment of choice in management of caudate lobe liver abscess.

  5. Lee Y, Roslan R, Azizan S, Firdaus-Raih M, Ramlan EI
    BMC Bioinformatics, 2016 Oct 28;17(1):438.
    PMID: 27793081
    BACKGROUND: Biological macromolecules (DNA, RNA and proteins) are capable of processing physical or chemical inputs to generate outputs that parallel conventional Boolean logical operators. However, the design of functional modules that will enable these macromolecules to operate as synthetic molecular computing devices is challenging.

    RESULTS: Using three simple heuristics, we designed RNA sensors that can mimic the function of a seven-segment display (SSD). Ten independent and orthogonal sensors representing the numerals 0 to 9 are designed and constructed. Each sensor has its own unique oligonucleotide binding site region that is activated uniquely by a specific input. Each operator was subjected to a stringent in silico filtering. Random sensors were selected and functionally validated via ribozyme self cleavage assays that were visualized via electrophoresis.

    CONCLUSIONS: By utilising simple permutation and randomisation in the sequence design phase, we have developed functional RNA sensors thus demonstrating that even the simplest of computational methods can greatly aid the design phase for constructing functional molecular devices.

  6. Hayashi M, Kawakami F, Roslan R, Hapiszudin NM, Dharmalingam S
    Primates, 2018 Mar;59(2):135-144.
    PMID: 29383576 DOI: 10.1007/s10329-018-0650-2
    The Bukit Merah Orang Utan Island (OUI) Foundation has been conducting behavioral and veterinary research on orangutans as an attempt at ex situ conservation. Since 2010, the Primate Research Institute, Kyoto University has been collaborating with OUI to promote environmental enrichment and infant rearing by biological mothers in addition to the continuous efforts of refining the veterinary management of the endangered species. In 2011, three Bornean orangutans (Pongo pygmaeus pygmaeus) were released on an island, called BJ Island, adjacent to OUI. This island is approximately 5.6 ha in size, and 635 trees belonging to 102 plant species were identified prior to their release. Behavioral monitoring of the released individuals has been conducted to evaluate their behavioral adaptation to the new environment. Two of the three released orangutans were born in the wild, whereas the youngest individual was born on OUI and expected to learn forest survival strategies from the two older individuals. One of the orangutans was pregnant at the time of release and subsequently gave birth to two male infants on BJ Island. The behavioral monitoring indicated that these orangutans traveled more and spent more time on trees following their release onto BJ Island. However, resting was longer for two females both on OUI and BJ Island when compared to other populations. The orangutans consumed some natural food resources on BJ Island. The release into a more naturalistic environment may help the orangutans to develop more naturalistic behavioral patterns that resemble their wild counterparts.
  7. Azizul FM, Alsabery AI, Hashim I, Roslan R, Saleh H
    Sci Rep, 2023 Jun 14;13(1):9660.
    PMID: 37316564 DOI: 10.1038/s41598-023-36297-9
    Two dimensional wavy walls rectangular cavity with inclined magnetohydrodynamic has been examined in mixed convection configurations. Triple fins arranged in the upwards ladder were filled within alumina nanoliquid in the cavity. Vertical sinusoidal walls were heated, and the other side was kept cold while both horizontal walls were kept adiabatic. All walls were motionless except the top cavity that was driven to the right. The diversified range of control parameter in Richardson number, Hartmann number, number of undulations, length of the cavity has been performed in this study. The analysis was simulated using finite element method by employing the governing equation formula, and the results were delineated in the form of streamlines, isotherms, heatlines, and comparisons on several relationships between the local velocity in the y-axis line of 0.6, local and average Nusselt number along the heated surface and dimensionless average temperature. The findings revealed that high concentration nanofluids boost the rate of heat transfer without the need to apply any magnetic field. Results found that the best heat mechanisms are natural convection with significant-high Richardson number as well as constructing two waves on the vertical walls in the cavity.
  8. Roslan R, Othman RM, Shah ZA, Kasim S, Asmuni H, Taliba J, et al.
    Comput Biol Med, 2010 Jun;40(6):555-64.
    PMID: 20417930 DOI: 10.1016/j.compbiomed.2010.03.009
    Protein-protein interactions (PPIs) play a significant role in many crucial cellular operations such as metabolism, signaling and regulations. The computational methods for predicting PPIs have shown tremendous growth in recent years, but problem such as huge false positive rates has contributed to the lack of solid PPI information. We aimed at enhancing the overlap between computational predictions and experimental results in an effort to partially remove PPIs falsely predicted. The use of protein function predictor named PFP() that are based on shared interacting domain patterns is introduced in this study with the purpose of aiding the Gene Ontology Annotations (GOA). We used GOA and PFP() as agents in a filtering process to reduce false positive pairs in the computationally predicted PPI datasets. The functions predicted by PFP() were extracted from cross-species PPI data in order to assign novel functional annotations for the uncharacterized proteins and also as additional functions for those that are already characterized by the GO (Gene Ontology). The implementation of PFP() managed to increase the chances of finding matching function annotation for the first rule in the filtration process as much as 20%. To assess the capability of the proposed framework in filtering false PPIs, we applied it on the available S. cerevisiae PPIs and measured the performance in two aspects, the improvement made indicated as Signal-to-Noise Ratio (SNR) and the strength of improvement, respectively. The proposed filtering framework significantly achieved better performance than without it in both metrics.
  9. Jamil DF, Saleem S, Roslan R, Al-Mubaddel FS, Rahimi-Gorji M, Issakhov A, et al.
    Comput Methods Programs Biomed, 2021 May;203:106044.
    PMID: 33756187 DOI: 10.1016/j.cmpb.2021.106044
    BACKGROUND AND OBJECTIVE: Arterial diseases would lead to several serious disorders in the cardiovascular system such as atherosclerosis. These disorders are mainly caused by the presence of fatty deposits, cholesterol and lipoproteins inside blood vessel. This paper deals with the analysis of non-Newtonian magnetic blood flow in an inclined stenosed artery.

    METHODS: The Casson fluid was used to model the blood that flows under the influences of uniformly distributed magnetic field and oscillating pressure gradient. The governing fractional differential equations were expressed using the Caputo Fabrizio fractional derivative without singular kernel.

    RESULTS: The analytical solutions of velocities for non-Newtonian model were then calculated by means of Laplace and finite Hankel transforms. These velocities were then presented graphically. The result shows that the velocity increases with respect to Reynolds number and Casson parameter, while decreases when Hartmann number increases.

    CONCLUSIONS: Casson blood was treated as the non-Newtonian fluid. The MHD blood flow was accelerated by pressure gradient. These findings are beneficial for studying atherosclerosis therapy, the diagnosis and therapeutic treatment of some medical problems.

  10. Mehmood OU, Bibi S, Jamil DF, Uddin S, Roslan R, Akhir MKM
    Sci Rep, 2021 10 14;11(1):20379.
    PMID: 34650140 DOI: 10.1038/s41598-021-99499-z
    The current work analyzes the effects of concentric ballooned catheterization and heat transfer on the hybrid nano blood flow through diseased arterial segment having both stenosis and aneurysm along its boundary. A fractional second-grade fluid model is considered which describes the non-Newtonian characteristics of the blood. Governing equations are linearized under mild stenosis and mild aneurysm assumptions. Precise articulations for various important flow characteristics such as heat transfer, hemodynamic velocity, wall shear stress, and resistance impedance are attained. Graphical portrayals for the impact of the significant parameters on the flow attributes have been devised. The streamlines of blood flow have been examined as well. The present finding is useful for drug conveyance system and biomedicines.
  11. Uddin S, Mehmood OU, Mohamad M, Roslan R, Khan I, Mohamed A
    Heliyon, 2023 Feb;9(2):e13210.
    PMID: 36814629 DOI: 10.1016/j.heliyon.2023.e13210
    In this paper, we studied the effect of a magnetic field on the non-isothermal second-grade fluid confined in a vertically oscillating cylinder. The flow solution is magnetized using the perpendicular magnetic field. The resultant fluid flow is due to the oscillating boundary motion and buoyancy force. Here, the MHD flow is modeled using the Caputo-Fabrizio non-integer derivative approach. The exact solution of the governing continuity, momentum and energy equations is obtained by means of Laplace and finite Hankel transforms. The commercial simulation software, Mathematica is used for calculating the roots of the Bessel function. The effects of dimensionless parameters such as Grashof and Prandtl numbers, magnetic field and fractional parameters on the second-grade fluid flow are analyzed. Heat transfer is high at a small Prandtl number. Velocity correlates positively with Grashof number and magnetic field, and negatively with Prandtl number. The heat and mass transfer results obtained from both conventional and fractional models are compared as well.
  12. Jamil DF, Uddin S, Kazi M, Roslan R, Gorji MR, Kamalrulzaman Md Akhir M
    Heliyon, 2023 Nov;9(11):e21780.
    PMID: 38027788 DOI: 10.1016/j.heliyon.2023.e21780
    This study investigates a fractional-order time derivative model of non-Newtonian magnetic blood flow in the presence of thermal radiation and body acceleration through an inclined artery. The blood flow is formulated using the Casson fluid model under the control of a uniformly distributed magnetic field and an oscillating pressure gradient. Caputo-Fabrizio's fractional derivative mathematical model was used, along with Laplace transform and the finite Hankel transform technique. Analytical expressions were obtained for the velocity of blood flow, magnetic particle distribution, and temperature profile. These distributions are presented graphically using Mathcad software. The results show that the velocity increases with the time, Reynolds number and Casson fluid parameters, and diminishes when Hartmann number increases. Moreover, fractional parameters, radiation values, and metabolic heat source play an essential role in controlling the blood temperature. More precisely, these results are beneficial for the diagnosis and treatment of certain medical issues.
  13. Amran UA, Salleh KM, Zakaria S, Roslan R, Chia CH, Jaafar SNS, et al.
    Polymers (Basel), 2021 Sep 11;13(18).
    PMID: 34577973 DOI: 10.3390/polym13183072
    Development of polyurethane foam (PUF) containing bio-based components is a complex process that requires extensive studies. This work reports on the production of rigid PUFs from polyol obtained via liquefaction of oil palm empty fruit bunch (EFB) biomass with different isocyanate (NCO) indexes. The effect of the NCO index on the physical, chemical and compressive properties of the liquefied EFB-based PUF (EFBPUF) was evaluated. The EFBPUFs showed a unique set of properties at each NCO index. Foaming properties had affected the apparent density and cellular morphology of the EFBPUFs. Increasing NCO index had increased the crosslink density and dimensional stability of the EFBPUFs via formation of isocyanurates, which had also increased their thermal stability. Combination of both foaming properties and crosslink density of the EFBPUFs had influenced their respective compressive properties. The EFBPUF produced at the NCO index of 120 showed the optimum compressive strength and released the least toxic hydrogen cyanide (HCN) gas under thermal degradation. The normalized compressive strength of the EFBPUF at the NCO index of 120 is also comparable with the strength of the PUF produced using petrochemical polyol.
  14. Nik Mohd Fakhruddin NNI, Khor JH, Suhaimi NFS, Zulkepli NYF, Roslan R, Wong ES, et al.
    MyJurnal
    Diabetes Mellitus is a disease due to reduced insulin sensitivity and secretion in the body which associated with obesity and hypertension. This study aimed to determine the influence of family support and self-motivation towards dietary compliance and glycaemic control among Type 2 Diabetes Mellitus (T2DM) outpatients. This cross-sectional study involved 35 subjects selected from Universiti Kebangsaan Malaysia Medical Centre (UKMMC) in Cheras and Ampangan Health Clinic in Seremban. Anthropometric measurements and fasting blood glucose have been obtained. Face-to-face interview session was done to obtain socio-demographic and diet intake. Further, dietary compliance, social support and self-motivation were assessed using Summary Diabetes Self Care Activities (SDSCA), Diabetes Social Support Questionnaire Family version (DSSQ-Fa) and Treatment Self-Regulation Questionnaire (TSRQ), respectively. Only 8.6% of subjects complied with dietary counselling. Fasting blood glucose for both men (7.93 ± 1.99 mmol/L) and women (8.77 ± 3.08 mmol/L) were higher than normal range. Self-motivation (r = 0.358, p < 0.05) and family support (r = 0.460, p < 0.01) significantly correlated with dietary compliance. Self-motivation and family support are important factors which can increase compliance towards dietary counseling. Further investigation should be carried out to determine factors that may influence dietary compliance and family support towards achieving desirable glycaemic control among T2DM patients.
    Study site: Klinik Warga UKMMC, Pusat Perubatan Universiti Kebangsaan Malaysia (PPUKM), Kuala Lumpur; Klinik Kesihatan Ampangan, Seremban, Negeri Sembilan, Malaysia
  15. Suteris NN, Yasin A, Misnon II, Roslan R, Zulkifli FH, Rahim MHA, et al.
    Int J Biol Macromol, 2021 Dec 29;198:147-156.
    PMID: 34971642 DOI: 10.1016/j.ijbiomac.2021.12.006
    This article demonstrates the development of nanofibrous cloths by electrospinning of renewable materials, i.e., curcumin-loaded 90% cellulose acetate (CA)/10% poly(ε-caprolactone) (PCL), for applications in regenerative medicine. The CA is derived from the biomass waste of the oil palm plantation (empty fruit bunch). The nanofiber scaffolds are characterized for the fiber morphology, microstructure, thermal properties, and wettability. The optimized smooth and bead-free electrospun fiber cloth contains 90% CA and 10% PCL in two curcumin compositions (0.5 and 1 wt%). The role of curcumin is shown to be two-fold: the first is its function as a drug and the second is its role in lowering the water contact angle and increasing the hydrophilicity. The hydrophilicity enhancements are related to the hydrogen bonding between the components. The enhanced hydrophilicity contributed to improve the swelling behavior of the scaffolds; the CA/PCL/Cur (0.5%) and the CA/PCL/Cur (1.0%) showed swelling of ~700 and 950%, respectively, in phosphate-buffered saline (PBS). The drug-release studies revealed the highest cumulative drug release of 60% and 78% for CA/PCL/Cur (0.5%) and CA/PCL/Cur (1.0%) nanofibers, respectively. The in-vitro studies showed that CA/PCL/Cur (0.5 wt%) and CA/PCL/Cur (1.0 wt%) nanofiber scaffolds facilitate a higher proliferation and expression of actin in fibroblasts than those scaffolds without curcumin for wound healing applications.
  16. Nadzirah S, Mohamad Zin N, Khalid A, Abu Bakar NF, Kamarudin SS, Zulfakar SS, et al.
    Crit Rev Anal Chem, 2023 Jun 26.
    PMID: 37358486 DOI: 10.1080/10408347.2023.2224433
    Since diagnostic laboratories handle large COVID-19 samples, researchers have established laboratory-based assays and developed biosensor prototypes. Both share the same purpose; to ascertain the occurrence of air and surface contaminations by the SARS-CoV-2 virus. However, the biosensors further utilize internet-of-things (IoT) technology to monitor COVID-19 virus contamination, specifically in the diagnostic laboratory setting. The IoT-capable biosensors have great potential to monitor for possible virus contamination. Numerous studies have been done on COVID-19 virus air and surface contamination in the hospital setting. Through reviews, there are abundant reports on the viral transmission of SARS-CoV-2 through droplet infections, person-to-person close contact and fecal-oral transmission. However, studies on environmental conditions need to be better reported. Therefore, this review covers the detection of SARS-CoV-2 in airborne and wastewater samples using biosensors with comprehensive studies in methods and techniques of sampling and sensing (2020 until 2023). Furthermore, the review exposes sensing cases in public health settings. Then, the integration of data management together with biosensors is well explained. Last, the review ended with challenges to having a practical COVID-19 biosensor applied for environmental surveillance samples.
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