Displaying publications 41 - 60 of 83 in total

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  1. Goh JH, Fazir M, Zainal-Abidin NA, Amir D, Singh M
    Malays Orthop J, 2016 Jul;10(2):56-60.
    PMID: 28435564 MyJurnal DOI: 10.5704/MOJ.1607.012
    Spinal tuberculosis is not common in the paediatric age group. Initial clinical features are often vague and non specific until the disease progresses to later stages. We highlight the diagnostic difficulties and management challenges of a complicated extradural tuberculoma with neurological deficits in a very young girl.
  2. Bajaj V, Anshuman R, Verma N, Singh MP, Tandon A
    Malays Orthop J, 2018 Nov;12(3):14-18.
    PMID: 30555641 DOI: 10.5704/MOJ.1811.003
    Introduction: Correlation of Pirani score and foot bimalleolar (FBM) angle has been used in few studies but correlation of FBM angle with ultrasonography has never been evaluated so they are being correlated in assessing the severity of clubfoot in neonates treated by Ponseti method. Material and Methods: Thirty-two feet with congenital talipes equinovarus (CTEV) deformity in neonates were prospectively treated by the Ponseti method. FBM angle and ultrasound parameters were measured three times i.e. at the time of initial presentation, at four weeks of treatment and at completion of treatment. The feet were divided according to the Pirani score in groups: one (0-2.0), two (2.5-4) and three (4.5-6). Correlation between FBM angle and ultrasound parameters were evaluated using Pearson correlation/regression. Results: Correlation between FBM angle and ultrasound parameters were statistically significant (p-value < 0.05). Conclusion: Ultrasound has the potential to accurately depict the pathoanatomy in clubfoot. FBM angle and ultrasound are objective methods to assess the severity of clubfoot. FBM angle and ultrasonography correlated in severity of deformity and correction achieved along the course of treatment.
  3. Sakib S, Hoque A, Rahim SKBA, Singh M, Sahar NM, Islam MS, et al.
    Materials (Basel), 2023 Jan 30;16(3).
    PMID: 36770180 DOI: 10.3390/ma16031172
    This paper reports a central spiral split-rectangular-shaped metamaterial absorber surrounded by a polarization-insensitive ring resonator for s-band applications. The rated absorption is 99.9% at 3.1 GHz when using a three-layer structure where the top and ground are made of copper and the center dielectric material is a commonly used FR-4 substrate. The central split gaps have an impact on the unit cell by increasing high absorption, and an adequate electric field is apparent in the outer split ring gap. At 3.1 GHz, the permittivity and permeability are negative and positive, respectively, so the proposed unit cell acts as an epsilon negative (ENG) metamaterial absorber. In a further analysis, Roger4450B was used as a substrate and obtained excellent absorption rates of 99.382%, 99.383%, 99.91%, and 95.17% at 1.44, 3.96, 4.205, and 5.025 GHz, respectively, in the S- and C-band regions. This unit cell acts as a single negative metamaterial (SNG) absorber at all resonance frequencies. The S11 and S21 parameters for FR-4 and Rogers4450B were simulated while keeping the polarization angle (θ and φ) at 15, 30, 45, 60, 75, and 90 degrees to measure, permittivity, permeability, reflective index, absorption, and reflection. The values of the reflective index are near zero. Near-zero reflective indexes (NZRI) are widely used in antenna gain propagation. The unit cell fabricated for the FR-4 substrate attained 99.9% absorption. S-band values in the range of (2-4) GHz can be applied for low-frequency radar detection.
  4. Karan D, Dubey S, Gunewardena S, Iczkowski KA, Singh M, Liu P, et al.
    Mol Oncol, 2024 Apr 11.
    PMID: 38605607 DOI: 10.1002/1878-0261.13637
    The androgen receptor (AR) is the main driver in the development of castration-resistant prostate cancer, where the emergence of AR splice variants leads to treatment-resistant disease. Through detailed molecular studies of the marine alkaloid manzamine A (MA), we identified transcription factor E2F8 as a previously unknown regulator of AR transcription that prevents AR synthesis in prostate cancer cells. MA significantly inhibited the growth of various prostate cancer cell lines and was highly effective in inhibiting xenograft tumor growth in mice without any pathophysiological perturbations in major organs. MA suppressed the full-length AR (AR-FL), its spliced variant AR-V7, and the AR-regulated prostate-specific antigen (PSA; also known as KLK3) and human kallikrein 2 (hK2; also known as KLK2) genes. RNA sequencing (RNA-seq) analysis and protein modeling studies revealed E2F8 interactions with DNA as a potential novel target of MA, suppressing AR transcription and its synthesis. This novel mechanism of blocking AR biogenesis via E2F8 may provide an opportunity to control therapy-resistant prostate cancer over the currently used AR antagonists designed to target different parts of the AR gene.
  5. Sim TS, Loke P, Lee MA, Singh M, Flotow H
    Parasitol Res, 2001 Sep;87(9):683-6.
    PMID: 11570549
    In this study, the genome of the Plasmodium falciparum Gombak A strain was examined for the presence of a gene encoding falcipain-2, a cysteine protease, using homology-based polymerase chain reaction cloning. The nucleotide sequence obtained from the gene cloned (designated pFG1) is approximately 99% homologous to other falcipain-2 genes from different strains. Comparatively, it is 69% homologous to falcipain-3 genes. Direct cloning of the falcipain-2 gene and its resemblance to the reported corresponding mRNA transcript suggests the absence of introns in this gene. Sequence alignment and comparison revealed four amino acid differences at positions 15, 51, 59 and 414 in the falcipain-2 from P. falciparum Gombak A as compared to other falcipain-2 proteins from different strains.
  6. Gautam D, Dolma KG, Khandelwal B, Gupta M, Singh M, Mahboob T, et al.
    PeerJ, 2023;11:e15590.
    PMID: 37529215 DOI: 10.7717/peerj.15590
    The biosynthesis of nanoparticles using the green route is an effective strategy in nanotechnology that provides a cost-effective and environmentally friendly alternative to physical and chemical methods. This study aims to prepare an aqueous extract of Ocimum sanctum (O. sanctum)-based silver nanoparticles (AgNPs) through the green route and test their antibacterial activity. The biosynthesized silver nanoparticles were characterised by colour change, UV spectrometric analysis, FTIR, and particle shape and size morphology by SEM and TEM images. The nanoparticles are almost spherical to oval or rod-shaped with smooth surfaces and have a mean particle size in the range of 55 nm with a zeta potential of -2.7 mV. The antibacterial activities of AgNPs evaluated against clinically isolated multidrug-resistant Acinetobacter baumannii (A. baumannii) showed that the AgNPs from O. sanctum are effective in inhibiting A. baumannii growth with a zone of inhibition of 15 mm in the agar well diffusion method and MIC and MBC of 32 µg/mL and 64 µg/mL, respectively. The SEM images of A. baumannii treated with AgNPs revealed damage and rupture in bacterial cells. The time-killing assay by spectrophotometry revealed the time- and dose-dependent killing action of AgNPs against A. baumannii, and the assay at various concentrations and time intervals indicated a statistically significant result in comparison with the positive control colistin at 2 µg/mL (P 
  7. Faruque MR, Hossain MI, Misran N, Singh M, Islam MT
    PLoS One, 2015;10(11):e0142663.
    PMID: 26599584 DOI: 10.1371/journal.pone.0142663
    A metamaterial-embedded planar inverted-F antenna (PIFA) is proposed in this study for cellular phone applications. A dual-band PIFA is designed to operate both GSM 900 MHz and DCS 1800 MHz. The ground plane of a conventional PIFA is modified using a planar one-dimensional metamaterial array. The investigation is performed using the Finite Integration Technique (FIT) of CST Microwave Studio. The performance of the developed antenna was measured in an anechoic chamber. The specific absorption rate (SAR) values are calculated considering two different holding positions: cheek and tilt. The SAR values are measured using COMOSAR measurement system. Good agreement is observed between the simulated and measured data. The results indicate that the proposed metamaterial-embedded antenna produces significantly lower SAR in the human head compared to the conventional PIFA. Moreover, the modified antenna substrate leads to slight improvement of the antenna performances.
  8. Darzi S, Islam MT, Tiong SK, Kibria S, Singh M
    PLoS One, 2015;10(11):e0140526.
    PMID: 26552032 DOI: 10.1371/journal.pone.0140526
    In this paper, stochastic leader gravitational search algorithm (SL-GSA) based on randomized k is proposed. Standard GSA (SGSA) utilizes the best agents without any randomization, thus it is more prone to converge at suboptimal results. Initially, the new approach randomly choses k agents from the set of all agents to improve the global search ability. Gradually, the set of agents is reduced by eliminating the agents with the poorest performances to allow rapid convergence. The performance of the SL-GSA was analyzed for six well-known benchmark functions, and the results are compared with SGSA and some of its variants. Furthermore, the SL-GSA is applied to minimum variance distortionless response (MVDR) beamforming technique to ensure compatibility with real world optimization problems. The proposed algorithm demonstrates superior convergence rate and quality of solution for both real world problems and benchmark functions compared to original algorithm and other recent variants of SGSA.
  9. Rokunuzzaman M, Islam MT, Arshad H, Jit Singh M, Misran N
    PLoS One, 2015;10(7):e0132530.
    PMID: 26177376 DOI: 10.1371/journal.pone.0132530
    This paper addresses the performance evaluation of a modified square loop antenna design for UHF RFID applications that is excited through a narrow feed line connected to a square loop, an impedance matching network. The square loop dimensions are modified to reach a conjugate impedance matching. A gap is fixed between the feed-lines to link the chip. To achieve impedance matching, the structures of the feed-line are optimized accordingly. In addition, the antenna consists of a straightforward geometry. An 11.9-meter maximum read range is achieved using a compact size of 80 × 44 mm2 and 3.2 W for the effective isotropic radiated power. Additional findings reveal that the proposed tag antenna is able to provide a stable resonance response in the near field of a large metallic surface.
  10. Rokunuzzaman M, Islam MT, Rowe WS, Kibria S, Jit Singh M, Misran N
    PLoS One, 2016;11(8):e0161293.
    PMID: 27533470 DOI: 10.1371/journal.pone.0161293
    A semi-circle looped vertically omnidirectional radiation (VOR) patterned tag antenna for UHF (919-923 MHz for Malaysia) frequency is designed to overcome the impedance mismatch issue in this paper. Two impedance matching feeding strips are used in the antenna structure to tune the input impedance of the antenna. Two dipole shaped meandered lines are used to achieve a VOR pattern. The proposed antenna is designed for 23-j224 Ω chip impedance. The antenna is suitable for 'place and tag' application. A small size of 77.68×35.5 mm2 is achieved for a read range performance of 8.3 meters using Malaysia regulated maximum power transfer of 2.0 W effective radiated power (ERP).
  11. Rashid A, Singh MK, Feng SS, Yatim NM, Sahak MY, Mahmud R
    Radiol Case Rep, 2020 Aug;15(8):1280-1284.
    PMID: 32577147 DOI: 10.1016/j.radcr.2020.04.054
    Morel Lavallée lesion or closed degloving injury is normally associated with severe trauma and occurs when the skin and subcutaneous fatty tissue traumatically and abruptly separated from the underlying fascia thus creating a potential space filled with fluid. MVA is the commonest etiology but large or lethal Morel Lavallée is extremely rare. A 35 years old, female pillion rider was involved in a motor vehicle accident and sustained injuries to the left pelvis and thigh. Emergency laparotomy and intra-op abdominal and bilateral lower limb arteriogram revealed no significant finding. Her general condition and vital signs continued to deteriorate despite aggressive resuscitation and eventually died. Post-Mortem Computed Tomography and Post-Mortem Computed Tomography Angiogram was performed and revealed a large cavity in the left thigh suggestive of a lethal Morel Lavallée lesion. Findings were confirmed by conventional autopsy.
  12. Rahman AAM, Islam MT, Moniruzzaman M, Rahim SKA, Singh M, Misran N, et al.
    Sci Rep, 2023 Sep 24;13(1):15943.
    PMID: 37743360 DOI: 10.1038/s41598-023-43182-y
    In this article, a unique metamaterial (MTM) structure is presented that exhibits four resonances of transmission coefficient (S21) that fall into S, X, and Ku bands. The MTM design is initiated on a Rogers (RT5880) substrate with an electrical dimension of 0.088 λ × 0.088 λ (λ is calculated at 3.424 GHz). The resonating patch contains four quartiles connected by a central metallic strip. The placement of each quartile is such that the whole resonator is mirror symmetric about the vertical axis. Two H-shaped modifiers connect two quartiles of each vertical half of the resonator. These H-shaped modifiers form the resonance cavity in its vicinity, and thus help significantly to orient the overall resonances of the proposed MTM at 3.424 GHz, 10 GHz, 14.816 GHz, and 16.848 GHz. The resonance phenomena are examined through equivalent circuit modeling and verified in Advanced Design Software (ADS). Metamaterial properties of the proposed MTM are extracted and it exhibits negative permittivity, permeability, and refractive index. The prototype of the MTM is fabricated and measurement is taken. The measured S21 shows a close similarity with the simulated result. Moreover, effective medium ratio (EMR) is calculated for the proposed MTM and a high EMR of 10.95 is obtained that expresses its compactness. This compact MTM with negative permittivity, permittivity, and refractive index can be important component for improving the performance of the miniaturized devices for multi-band wireless communication systems.
  13. Pius Owoh N, Mahinderjit Singh M, Zaaba ZF
    Sensors (Basel), 2018 Jul 03;18(7).
    PMID: 29970823 DOI: 10.3390/s18072134
    Automatic data annotation eliminates most of the challenges we faced due to the manual methods of annotating sensor data. It significantly improves users’ experience during sensing activities since their active involvement in the labeling process is reduced. An unsupervised learning technique such as clustering can be used to automatically annotate sensor data. However, the lingering issue with clustering is the validation of generated clusters. In this paper, we adopted the k-means clustering algorithm for annotating unlabeled sensor data for the purpose of detecting sensitive location information of mobile crowd sensing users. Furthermore, we proposed a cluster validation index for the k-means algorithm, which is based on Multiple Pair-Frequency. Thereafter, we trained three classifiers (Support Vector Machine, K-Nearest Neighbor, and Naïve Bayes) using cluster labels generated from the k-means clustering algorithm. The accuracy, precision, and recall of these classifiers were evaluated during the classification of “non-sensitive” and “sensitive” data from motion and location sensors. Very high accuracy scores were recorded from Support Vector Machine and K-Nearest Neighbor classifiers while a fairly high accuracy score was recorded from the Naïve Bayes classifier. With the hybridized machine learning (unsupervised and supervised) technique presented in this paper, unlabeled sensor data was automatically annotated and then classified.
  14. Hoque A, Tariqul Islam M, Almutairi AF, Alam T, Jit Singh M, Amin N
    Sensors (Basel), 2018 Nov 30;18(12).
    PMID: 30513675 DOI: 10.3390/s18124209
    In this paper, a dual-band metamaterial absorber (MMA) ring with a mirror reflexed C-shape is introduced for X and Ku band sensing applications. The proposed metamaterial consists of two square ring resonators and a mirror reflexed C-shape, which reveals two distinctive absorption bands in the electromagnetic wave spectrum. The mechanism of the two-band absorber particularly demonstrates two resonance frequencies and absorption was analyzed using a quasi-TEM field distribution. The absorption can be tunable by changing the size of the metallic ring in the frequency spectrum. Design and analysis of the proposed meta-absorber was performed using the finite-integration technique (FIT)-based CST microwave studio simulation software. Two specific absorption peaks value of 99.6% and 99.14% are achieved at 13.78 GHz and 15.3 GHz, respectively. The absorption results have been measured and compared with computational results. The proposed dual-band absorber has potential applications in sensing techniques for satellite communication and radar systems.
  15. Pius Owoh N, Mahinderjit Singh M
    Sensors (Basel), 2020 Jun 09;20(11).
    PMID: 32526843 DOI: 10.3390/s20113280
    The proliferation of mobile devices such as smartphones and tablets with embedded sensors and communication features has led to the introduction of a novel sensing paradigm called mobile crowd sensing. Despite its opportunities and advantages over traditional wireless sensor networks, mobile crowd sensing still faces security and privacy issues, among other challenges. Specifically, the security and privacy of sensitive location information of users remain lingering issues, considering the "on" and "off" state of global positioning system sensor in smartphones. To address this problem, this paper proposes "SenseCrypt", a framework that automatically annotates and signcrypts sensitive location information of mobile crowd sensing users. The framework relies on K-means algorithm and a certificateless aggregate signcryption scheme (CLASC). It incorporates spatial coding as the data compression technique and message query telemetry transport as the messaging protocol. Results presented in this paper show that the proposed framework incurs low computational cost and communication overhead. Also, the framework is robust against privileged insider attack, replay and forgery attacks. Confidentiality, integrity and non-repudiation are security services offered by the proposed framework.
  16. Singh M, Mackinlay LM, Kane GJ, Mak JW, Yap EH, Ho BC, et al.
    Am J Trop Med Hyg, 1980 Jul;29(4):548-52.
    PMID: 6996501
    The indirect hemagglutination (IHA) test done with turkey red cells was applied to 173 serum samples obtained from patients and persons exposed to Wuchereria bancrofti and Brugia malayi in endemic areas of Peninsular Malaysia. A crude extract of adult worms of the rat filaria, Breinlia booliati, was used as the antigen. When a titer of 1:16 was taken as negative, positive IHA test rates in sera from microfilaria-negative persons in endemic areas, microfilaremic cases, and patients with clinical filariasis were 13%, 75%, and 80%, respectively. Results of the IHA test correlated well with results obtained with the indirect fluorescent technique.
  17. Singh M
    Br J Ophthalmol, 1988 Nov;72(11):820-2.
    PMID: 3207656
    In a prospective study 84 patients with aphakic retinal detachment were treated either by local scleral buckling alone or combined with an encirclement. The rate of surgical reattachment of the retina was found to be similar with either technique over a minimum follow-up period of one year. Simplicity and a low incidence of serious complications of the local procedure merit its application as the initial method of repairing aphakic detachments.
  18. Singh M, Kaur B, Annuar NM
    Br J Ophthalmol, 1988 Feb;72(2):131-3.
    PMID: 3349013
    A rare case of choroidal malignant melanoma in a naevus of Ota is described. This is the first reported case from Asia outside the Japanese population. This case illustrates the need for close observation of all pigmented lesions of the eye.
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