Displaying all 17 publications

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  1. Nazmi N, Zainal D, Hashim M
    PMID: 9561623
    Records of 183 patients with renal stones managed at Hospital Universiti Sains Malaysia between 1985 and 1995 were retrospectively evaluated. The commonest symptom was lumbar pain which may be associated with either frequency, blood stained urine or dysuria. One hundred and sixty-one patients (88%) had upper tract stones while the remainder had lower tract stones. Positive urine cultures were seen in 33 patients. The commonest organism isolated was Escherichia coli followed by Klebsiella aeruginosa and Staphylococcus aureus. Almost all of our patients had renal impairment at presentation and 70% of them progressed to chronic renal failure. In contrast to previous findings, the pattern of renal stone in this region is similar to that described in Western society. Its effect on renal function is serious and hence warrant special attention.
  2. Zainal D, Monniaty M, Nazmi N
    PMID: 9139394
    The pattern and outcome of patients with chronic renal failure (CRF) in Kelantan, the northeastern state of Malaysia was determined. A total of 60 patients with CRF managed at the Hospital Universiti Sains Malaysia between January 1991 and June 1993 were reviewed retrospectively. The prevalence of CRF was 24.8 patients per year. The ratio of male to female patients was 1.5 : 1.0. Their mean age at presentation was 51.4 +/- 13.7 years. The cause of CRF in majority of our patients was unknown. Their mean blood urea and serum creatinine were 38.9 +/- 9.8 mmol/l and 1,154.9 +/- 458.7 mumol/l respectively. Sixty-five percent of our patients were already in end-stage renal failure (ESRF) at the time of presentation and only 53.8% of them could afford a definitive renal replacement therapy. Their mortality rate was 21.7% and majority of the death occurred in patients who were not receiving definitive renal replacement therapy. This debilitating course will continue unless the cost of renal replacement therapy is subsidised or a renal transplantation program is activated. Hence public education to encourage organ donation in this part of Malysia is necessary.
  3. Nazmi, N. N. M., Isa, M. I. N., Sarbon, N. M.
    MyJurnal
    Protein-based films are thin and flexible films derived from protein sources. They are
    completely biodegradable and used in food engineering, packaging, drug recovery, and other
    applications. In food packaging, gelatin is widely used due to properties such as low cost,
    availability, functional attributes, mechanical (flexibility and tension) and optical (brightness
    and opacity) strength, barrier against gas flow, and structural resistance to water and
    microorganisms. Therefore, this paper reviews the characterisation of biodegradable
    protein-based films from gelatin alternatives, mainly from fish and chicken skin, as food
    packaging materials. The properties of film packaging derived from gelatin alternatives were
    compared with films derived from mammalian gelatin. The findings showed that the blended
    gelatin alternatives with polysaccharide improved physical properties such as water vapour
    permeability, gas permeability, light transmission and transparency, thermal properties,
    microstructure, colour, and heat sealability. Moreover, improvements in mechanical
    properties such as tensile strength and elongation at break were also investigated. This review
    also comes out with suggestions for future research on the compatibility between gelatin films
    and food ingredients. This paper provides a comprehensive overview that promotes the
    development of biodegradable blended films from gelatin alternatives for packaging
    applications in the food industry and related fields.
  4. Jahit, I. S., Nazmi, N. N. M., Isa, M. I. N., Sarbon, N. M.
    MyJurnal
    This study examined the effects of drying temperatures (25 and 45 °C) on the physical properties
    of different formulations of gelatin/CMC/chitosan composite films. The physical properties
    of each formulated film were assessed via Fourier Transform Infra-Red (FTIR) spectroscopy,
    X-Ray Diffractometry (XRD), Water Vapour Permeability (WVP) and biodegradability. The
    incorporation of CMC and chitosan significantly influenced film properties. Increased chitosan
    concentrations reduced the film’s amorphous character by increasing its crystalline structure.
    The blended films also exhibited amino peaks that shifted from 1542 to ~1548 cm-1 while NH
    and/or OH peaks shifted from 3384 to 3288 cm-1. Formulation E had the second lowest WVP
    for both drying condition and the highest weight loss for biodegradability after burial in soil for
    5 days. In conclusion, different temperature did not affect the properties of film produced and
    formulation E qualified as ‘high quality packaging material’ with promising potential for the
    food packaging industry.
  5. Kamaliah MD, Zainal D, Mokhtar N, Nazmi N
    Int J Dermatol, 1998 Jul;37(7):520-3.
    PMID: 9679693
    BACKGROUND: Previous studies have reported that drugs and infections are common causes of erythema multiforme (EM) and Stevens-Johnson syndrome (SJS). Toxic epidermal necrolysis (TEN) is mainly related to drugs. No study has been conducted in Kelantan, the northeastern state of Malaysia, to assess these cutaneous reactions.

    METHODS: A retrospective study of all hospitalized cases of EM, SJS, and TEN was conducted covering an 8-year period from 1987 to 1994.

    RESULTS: There were four cases (13.8%) of EM, 22 cases (75.9%) of SJS, and three cases (10.3%) of TEN. Drugs as a definitive cause was observed in one case (25%) of EM, 12 cases (54.5%) of SJS, and two cases (66.7%) of TEN. Drugs as a probable cause was observed in seven cases (31.8%) of SJS and one case (33.3%) of TEN. The male to female ratio was equal in EM and SJS. Antiepileptics were the commonest culprits, followed by antibiotics. One patient died of SJS and one patient died of TEN, giving mortality rates of 4.5% and 33.5% respectively. Fever was noted in 18 patients (62.1%). Leukocytosis was noted in 10 patients (34.5%), and nine patients (31.0%) had elevated liver transaminase enzymes. No significant correlation was noted between these biochemical changes and cutaneous eruption. Secondary infections were observed in 11 patients (37.9%): Staphylococcus aureus was the commonest isolated organism.

    CONCLUSIONS: This study shows that drugs remain the commonest culprit in SJS and TEN. Despite adequate treatment, the mortality rate remains high, especially in TEN. These findings are similar to those of other reported studies.

  6. Norhaniza R, Mazlan SA, Ubaidillah U, Sedlacik M, Aziz SAA, Nazmi N, et al.
    Sensors (Basel), 2021 Feb 28;21(5).
    PMID: 33670872 DOI: 10.3390/s21051660
    Magnetoactive (MA) foam, with its tunable mechanical properties and magnetostriction, has the potential to be used for the development of soft sensor technology. However, researchers have found that its mechanical properties and magnetostriction are morphologically dependent, thereby limiting its capabilities for dexterous manipulation. Thus, in this work, MA foam was developed with additional capabilities for controlling its magnetostriction, normal force, storage modulus, shear stress and torque by manipulating the concentration of carbonyl iron particles (CIPs) and the magnetic field with regard to morphological changes. MA foams were prepared with three weight percentages of CIPs, namely, 35 wt.%, 55 wt.% and 75 wt.%, and three different modes, namely, zero shear, constant shear and various shears. The results showed that the MA foam with 75 wt.% of CIPs enhanced the normal force sensitivity and positive magnetostriction sensitivity by up to 97% and 85%, respectively. Moreover, the sensitivities of the storage modulus, torque and shear stress were 8.97 Pa/mT, 0.021 µN/mT, and 0.0096 Pa/mT, respectively. Meanwhile, the magnetic dipolar interaction between the CIPs was capable of changing the property of MA foam from a positive to a negative magnetostriction under various shear strains with a low loss of energy. Therefore, it is believed that this kind of highly sensitive MA foam can potentially be implemented in future soft sensor systems.
  7. Nazmi N, Abdul Rahman MA, Yamamoto S, Ahmad SA, Zamzuri H, Mazlan SA
    Sensors (Basel), 2016 Aug 17;16(8).
    PMID: 27548165 DOI: 10.3390/s16081304
    In recent years, there has been major interest in the exposure to physical therapy during rehabilitation. Several publications have demonstrated its usefulness in clinical/medical and human machine interface (HMI) applications. An automated system will guide the user to perform the training during rehabilitation independently. Advances in engineering have extended electromyography (EMG) beyond the traditional diagnostic applications to also include applications in diverse areas such as movement analysis. This paper gives an overview of the numerous methods available to recognize motion patterns of EMG signals for both isotonic and isometric contractions. Various signal analysis methods are compared by illustrating their applicability in real-time settings. This paper will be of interest to researchers who would like to select the most appropriate methodology in classifying motion patterns, especially during different types of contractions. For feature extraction, the probability density function (PDF) of EMG signals will be the main interest of this study. Following that, a brief explanation of the different methods for pre-processing, feature extraction and classifying EMG signals will be compared in terms of their performance. The crux of this paper is to review the most recent developments and research studies related to the issues mentioned above.
  8. Hapipi NM, Mazlan SA, Ubaidillah U, Abdul Aziz SA, Ahmad Khairi MH, Nordin NA, et al.
    Int J Mol Sci, 2020 Mar 05;21(5).
    PMID: 32151055 DOI: 10.3390/ijms21051793
    Chemically crosslinked hydrogel magnetorheological (MR) plastomer (MRP) embedded with carbonyl iron particles (CIPs) exhibits excellent magnetic performance (MR effect) in the presence of external stimuli especially magnetic field. However, oxidation and desiccation in hydrogel MRP due to a large amount of water content as a dispersing phase would limit its usage for long-term applications, especially in industrial engineering. In this study, different solvents such as dimethyl sulfoxide (DMSO) are also used to prepare polyvinyl alcohol (PVA) hydrogel MRP. Thus, to understand the dynamic viscoelastic properties of hydrogel MRP, three different samples with different solvents: water, DMSO, and their binary mixtures (DMSO/water) were prepared and systematically carried out using the oscillatory shear. The outcomes demonstrate that the PVA hydrogel MRP prepared from precursor gel with water shows the highest MR effect of 15,544% among the PVA hydrogel MRPs. However, the samples exhibit less stability and tend to oxidise after a month. Meanwhile, the samples with binary mixtures (DMSO/water) show an acceptable MR effect of 11,024% with good stability and no CIPs oxidation. Otherwise, the sample with DMSO has the lowest MR effect of 7049% and less stable compared to the binary solvent samples. This confirms that the utilisation of DMSO as a new solvent affects the rheological properties and stability of the samples.
  9. Jamari SKM, Nordin NA, Ubaidillah, Aziz SAA, Nazmi N, Mazlan SA
    Materials (Basel), 2020 Nov 24;13(23).
    PMID: 33255343 DOI: 10.3390/ma13235317
    Magnetorheological (MR) material is a type of magneto-sensitive smart materials which consists of magnetizable particles dispersed in a carrier medium. Throughout the years, coating on the surface of the magnetic particles has been developed by researchers to enhance the performance of MR materials, which include the improvement of sedimentation stability, enhancement of the interaction between the particles and matrix mediums, and improving rheological properties as well as providing extra protection against oxidative environments. There are a few coating methods that have been employed to graft the coating layer on the surface of the magnetic particles, such as atomic transfer radical polymerization (ATRP), chemical oxidative polymerization, and dispersion polymerization. This paper investigates the role of particle coating in MR materials with the effects gained from grafting the magnetic particles. This paper also discusses the coating methods employed in some of the works that have been established by researchers in the particle coating of MR materials.
  10. Johari MAF, Mazlan SA, Nasef MM, Ubaidillah U, Nordin NA, Aziz SAA, et al.
    Sci Rep, 2021 May 25;11(1):10936.
    PMID: 34035434 DOI: 10.1038/s41598-021-90484-0
    The widespread use of magnetorheological elastomer (MRE) materials in various applications has yet to be limited due to the fact that there are substantial deficiencies in current experimental and theoretical research on its microstructural durability behavior. In this study, MRE composed of silicon rubber (SR) and 70 wt% of micron-sized carbonyl iron particles (CIP) was prepared and subjected to stress relaxation evaluation by torsional shear load. The microstructure and particle distribution of the obtained MRE was evaluated by a field emission scanning electron microscopy (FESEM). The influence of constant low strain at 0.01% is the continuing concern within the linear viscoelastic (LVE) region of MRE. Stress relaxation plays a significant role in the life cycle of MRE and revealed that storage modulus was reduced by 8.7%, normal force has weakened by 27%, and stress performance was reduced by 6.88% along approximately 84,000 s test duration time. This time scale was the longest ever reported being undertaken in the MRE stress relaxation study. Novel micro-mechanisms that responsible for the depleted performance of MRE was obtained by microstructurally observation using FESEM and in-phase mode of atomic force microscope (AFM). Attempts have been made to correlate strain localization produced by stress relaxation, with molecular deformation in MRE amorphous matrix. Exceptional attention was focused on the development of molecular slippage, disentanglement, microplasticity, microphase separation, and shear bands. The relation between these microstructural phenomena and the viscoelastic properties of MRE was diffusely defined and discussed. The presented MRE is homogeneous with uniform distribution of CIP. The most significant recent developments of systematic correlation between the effects of microstructural deformation and durability performance of MRE under stress relaxation has been observed and evaluated.
  11. Lim PKC, Lee XC, Mohd Nazmi NMA, Tang YY, Wong SF, Mak JW, et al.
    Trop Biomed, 2018 Dec 01;35(4):1007-1016.
    PMID: 33601848
    Studies on parasite populations in Antarctic soils are scarce and thus little is known about the threat of these parasites towards either the natural fauna or human visitors. However, human presence in Antarctica, mainly through research and tourism, keeps increasing over time, potentially exposing visitors to zoonotic infections from Antarctic wildlife and environment. Most available literature to date has focused on faecal samples from Antarctic vertebrates. Therefore, this study addressed the possible presence of parasites in Antarctic soil that may be infectious to humans. Soil samples were obtained from five locations on Signy Island (South Orkney Islands, maritime Antarctic), namely North Point and Gourlay Peninsula (penguin rookeries), Pumphouse (relic coal-powered pump house), Jane Col (barren high altitude fellfield) and Berntsen Point (low altitude vegetated fellfield close to current research station). Approximately 10% of the soil samples (14/135) from 3 out of the 5 study sites had parasites which included Diphyllobotridae spp. eggs, Cryptosporidium sp., an apicomplexan protozoa (gregarine), Toxoplasma gondii, helminths (a cestode, Tetrabothrius sp., and a nematode larva) and mites. The presence of parasites in the 3 sites are most likely due to the presence of animal and human activities as two of these sites are penguin rookeries (North Point and Gourlay Peninsula) while the third site (Pumphouse Lake) has human activity. While some of the parasite species found in the soil samples appear to be distinctive, there were also parasites such as Cryptosporidium and Toxoplasma gondii that have a global distribution and are potentially pathogenic.
  12. Mohd Nasir NA, Nazmi N, Mohamad N, Ubaidillah U, Nordin NA, Mazlan SA, et al.
    Materials (Basel), 2021 Sep 06;14(17).
    PMID: 34501180 DOI: 10.3390/ma14175091
    The use of highly viscous grease as a medium in magnetorheological grease (MRG) provides the benefit of avoiding sedimentation from occurring. However, it limits the expansion of yield stress in the on-state condition, thus reducing the application performance during operation. Therefore, in this study, the improvement in the rheological properties of MRG was investigated through the introduction of graphite as an additive. MRG with 10 wt % graphite (GMRG) was fabricated, and its properties were compared to a reference MRG sample. The microstructure of GMRG was characterized using an environmental scanning electron microscope (ESEM). The rheological properties of both samples, including apparent viscosity, yield stress, and viscoelasticity, were examined using a shear rheometer in rotational and oscillatory modes. The results demonstrated a slight increase in the apparent viscosity in GMRG and a significant improvement in yield stress by 38.8% at 3 A with growth about 32.7% higher compared to MRG from 0 to 3 A. An expansion of the linear viscoelastic region (LVE) from 0.01% to 0.1% was observed for the GMRG, credited to the domination of the elastic properties on the sample. These obtained results were confirmed based on ESEM, which described the contribution of graphite to constructing a more stable chain structure in the GMRG. In conclusion, the findings highlight the influence of the addition of graphite on improving the rheological properties of MRG. Hence, the addition of graphite in MRG shows the potential to be applied in many applications in the near future.
  13. Johari MAF, Sarman AM, Mazlan SA, U U, Nordin NA, Abdul Aziz SA, et al.
    Materials (Basel), 2021 Aug 05;14(16).
    PMID: 34442907 DOI: 10.3390/ma14164384
    Micro mechanism consideration is critical for gaining a thorough understanding of amorphous shear band behavior in magnetorheological (MR) solids, particularly those with viscoelastic matrices. Heretofore, the characteristics of shear bands in terms of formation, physical evolution, and response to stress distribution at the localized region have gone largely unnoticed and unexplored. Notwithstanding these limitations, atomic force microscopy (AFM) has been used to explore the nature of shear band deformation in MR materials during stress relaxation. Stress relaxation at a constant low strain of 0.01% and an oscillatory shear of defined test duration played a major role in the creation of the shear band. In this analysis, the localized area of the study defined shear bands as varying in size and dominantly deformed in the matrix with no evidence of inhibition by embedded carbonyl iron particles (CIPs). The association between the shear band and the adjacent zone was further studied using in-phase imaging of AFM tapping mode and demonstrated the presence of localized affected zone around the shear band. Taken together, the results provide important insights into the proposed shear band deformation zone (SBDZ). This study sheds a contemporary light on the contentious issue of amorphous shear band deformation behavior and makes several contributions to the current literature.
  14. Saharuddin KD, Ariff MHM, Bahiuddin I, Ubaidillah U, Mazlan SA, Aziz SAA, et al.
    Sci Rep, 2022 Feb 17;12(1):2657.
    PMID: 35177686 DOI: 10.1038/s41598-022-06643-4
    This study introduces a novel platform to predict complex modulus variables as a function of the applied magnetic field and other imperative variables using machine learning. The complex modulus prediction of magnetorheological (MR) elastomers is a challenging process, attributable to the material's highly nonlinear nature. This problem becomes apparent when considering various possible fabrication parameters. Furthermore, traditional parametric modeling methods are limited when applied to solve larger-scale cases involving large databases. Consequently, the application of non-parametric modeling such as machine learning has gained increasing attraction in recent years. Therefore, this work proposes a data-driven approach for predicting multiple input-dependent complex moduli using feedforward neural networks. Besides excitation frequency and magnetic flux density as operating conditions, the inputs consider compositions and curing conditions represented by magnetic particle weight percentage and the curing magnetic field, respectively. Extreme learning machines and artificial neural networks were used to train the models. The simulation results obtained at various curing conditions and other inputs confirm that the predicted complex modulus has high accuracy with an R2 of about 0.997, as compared to the experimental results. Furthermore, the predicted complex modulus pattern and magnetorheological effect agree with the experimental data using both the learned and unlearned data.
  15. Hapipi NM, Mazlan SA, Ubaidillah U, Abdul Aziz SA, Choi SB, Nordin NA, et al.
    Sensors (Basel), 2021 Nov 22;21(22).
    PMID: 34833835 DOI: 10.3390/s21227758
    Polyvinyl alcohol (PVA)-based magnetorheological plastomer (MRP) possesses excellent magnetically dependent mechanical properties such as the magnetorheological effect (MR effect) when exposed to an external magnetic field. PVA-based MRP also shows a shear stiffening (ST) effect, which is very beneficial in fabricating pressure sensor. Thus, it can automatically respond to external stimuli such as shear force without the magnetic field. The dual properties of PVA-based MRP mainly on the ST and MR effect are rarely reported. Therefore, this work empirically investigates the dual properties of this smart material under the influence of different solvent compositions (20:80, 40:60, 60:40, and 80:20) by varying the ratios of binary solvent mixture (dimethyl sulfoxide (DMSO) to water). Upon applying a shear stress with excitation frequencies from 0.01 to 10 Hz, the storage modulus (G') for PVA-based MRP with DMSO to water ratio of 20:40 increases from 6.62 × 10-5 to 0.035 MPa. This result demonstrates an excellent ST effect with the relative shear stiffening effect (RSTE) up to 52,827%. In addition, both the ST and MR effect show a downward trend with increasing DMSO content to water. Notably, the physical state of hydrogel MRP could be changed with different solvent ratios either in the liquid-like or solid-like state. On the other hand, a transient stepwise experiment showed that the solvent's composition had a positive effect on the arrangement of CIPs within the matrix as a function of the external magnetic field. Therefore, the solvent ratio (DMSO/water) can influence both ST and MR effects of hydrogel MRP, which need to be emphasized in the fabrication of hydrogel MRP for appropriate applications primarily with soft sensors and actuators for dynamic motion control.
  16. Johari MAF, Mazlan SA, Nordin NA, Ubaidillah U, Aziz SAA, Nazmi N, et al.
    Micromachines (Basel), 2021 Aug 11;12(8).
    PMID: 34442570 DOI: 10.3390/mi12080948
    This paper presents the effect of the micro-sized particles on the storage modulus and durability characteristics of magnetorheological elastomers (MREs). The initial phase of the investigation is to determine any associations among the microparticles' weight percent fraction (wt%), structure arrangement, and the storage modulus of MRE samples. In order to carry out this, both isotropic and anisotropic types of MRE samples consisting of the silicone rubber matrix and 50, 60, 70, 75, and 80 wt% microparticles of carbonyl iron fractions are prepared. It is identified from the magneto-rheometer that the increase in storage modulus and decrease in linear viscoelastic region limit are observed in varying consistency depending on wt% and particle arrangement. The consistency of this dependency feature is highlighted by superimposing all of the graphs plotted to create the proposed the samples' behavior model. In response to increasing magnetic stimulation, a sample of 70 wt% microparticles with an isotropic arrangement is found to be significant and stable. The experimentally defined fraction is then used for the durability test as the second phase of the investigation. During this phase, the durability evaluation is subjected to stress relaxation for an extended period of time. After undergoing durability testing, storage modulus performance is decreased by 0.7-13% at various magnetic stimulation levels. This result directly indicates that the storage modulus characteristics of different forms of MRE are sensitive to the different iron particle fractions' and microparticles' alignment. Therefore, important treatments to alter the storage modulus can be undertaken before the practical implementation to accommodate any desired performance of MRE itself and MRE application systems.
  17. Zaini N, Mohamad N, Mazlan SA, Abdul Aziz SA, Choi SB, Hapipi NM, et al.
    Materials (Basel), 2021 Dec 06;14(23).
    PMID: 34885641 DOI: 10.3390/ma14237484
    Common sensors in many applications are in the form of rigid devices that can react according to external stimuli. However, a magnetorheological plastomer (MRP) can offer a new type of sensing capability, as it is flexible in shape, soft, and responsive to an external magnetic field. In this study, graphite (Gr) particles are introduced into an MRP as an additive, to investigate the advantages of its electrical properties in MRPs, such as conductivity, which is absolutely required in a potential sensor. As a first step to achieve this, MRP samples containing carbonyl iron particles (CIPs) and various amounts of of Gr, from 0 to 10 wt.%, are prepared, and their magnetic-field-dependent electrical properties are experimentally evaluated. After the morphological aspect of Gr-MRP is characterized using environmental scanning electron microscopy (ESEM), the magnetic properties of MRP and Gr-MRP are evaluated via a vibrating sample magnetometer (VSM). The resistivities of the Gr-MRP samples are then tested under various applied magnetic flux densities, showing that the resistivity of Gr-MRP decreases with increasing of Gr content up to 10 wt.%. In addition, the electrical conductivity is tested using a test rig, showing that the conductivity increases as the amount of Gr additive increases, up to 10 wt.%. The conductivity of 10 wt.% Gr-MRP is found to be highest, at 178.06% higher than the Gr-MRP with 6 wt.%, for a magnetic flux density of 400 mT. It is observed that with the addition of Gr, the conductivity properties are improved with increases in the magnetic flux density, which could contribute to the potential usefulness of these materials as sensing detection devices.
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