Displaying all 9 publications

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  1. Abdullah SM, Ahmad Z, Sulaiman K
    Sensors (Basel), 2014;14(6):9878-88.
    PMID: 24901979 DOI: 10.3390/s140609878
    An electrochemical cell using an organic compound, copper (II) phthalocyanine-tetrasulfonic acid tetrasodium salt (CuTsPc,) has been fabricated and investigated as a solution-based temperature sensor. The capacitance and resistance of the ITO/CuTsPc solution/ITO chemical cell has been characterized as a function of temperature in the temperature range of 25-80 °C. A linear response with minimal hysteresis is observed. The fabricated temperature sensor has shown high consistency and sensitive response towards a specific range of temperature values.
  2. Goh BS, Roopesh S, Marina MB, Abdullah SM
    Med J Malaysia, 2014 Feb;69(1):13-5.
    PMID: 24814622
    This is a retrospective study examining the outcome of paediatric patients with subglottic stenosis who underwent partial cricotracheal resection (PCTR) as a primary open procedure from 2004 to 2012. There were 5 patients identified aged from 3 to 18 years old. All the subglottic stenosis were acquired type. All of them were secondary to prolonged intubation. Three patients were classified as Myer-Cotton grade III and the other two were Myer-Cotton grade IV. Two of the patients had concomitant bilateral vocal cord immobility. All patients underwent two staged PCTR . All patients underwent two staged PCTR, and one patient underwent posterior cordectomy apart from partial CTR at different setting. All patients were successfully decannulated at various durations postoperatively. Although this is an early experience in our institution, PCTR has shown to be effective and safe procedure in patients with subglottic stenosis especially those with Myer-Cotton grade III and IV.
  3. Abdullah MA, Abdullah SM, Kumar SV, Hoque MZ
    Hematol Rep, 2019 Sep 18;11(3):8167.
    PMID: 31579124 DOI: 10.4081/hr.2019.8167
    A 3-year-old male child was presented with worsening abdominal pain, abdominal distension, lethargy, pallor and hepatosplenomegaly. The patient had multiple outpatient visits in the past and was treated with oral antibiotics, oral anthelmintic agents, albeit with minimal benefit. The patient also had non-neutropenic pyrexia spikes and oral ulcers. The patient was an adopted child; hence details about his biological parents' previous history were unclear. Differential diagnosis of Chronic Myelomonocytic Leukemia (CMML), Juvenile Myelomonocytic Leukemia (JMML), Gaucher's disease, Thalassemia and discrete pancreatic pathology was considered. Hemoglobin electrophoresis was indicative of thalassemia. Also, molecular detection method by polymerase chain reaction confirms a concurrent infection with Plasmodium knowlesi malaria. The BCR-ABL fusion gene was found to be negative. Correlating with peripheral monocytosis, bone marrow aspiration and trephine biopsy with blasts only 3-4% and hepatosplenomegaly, a diagnosis of JMML was established. We present a rare phenomenon with an overlap of signs and symptoms between JMML, underlying thalassemia, and Plasmodium knowlesi, posing a diagnostic challenge to physicians.
  4. Zhang L, Jin Y, Xia L, Xu B, Syed Abdullah SM
    Front Psychol, 2022;13:816168.
    PMID: 35519657 DOI: 10.3389/fpsyg.2022.816168
    The behavior decisions in social dilemmas are highlighted in sociological, economic, and social psychological studies. Across two studies, the iterated prisoner's dilemma is used as a basic paradigm to explore the effects of social distance and asymmetric reward and punishment on an individual's cooperative behavior. Experiment 1 (N = 80) used a 2 (social distance: intimacy vs. strangeness) × 2 (symmetry of rewards: symmetric rewards vs. asymmetric rewards) within-subject design and demonstrated that when there were only two options, namely, cooperation and defection, cooperative behavior was influenced by social distance and symmetry of rewards, respectively, and the interaction was not significant. Experiment 2 (N = 80) used a 2 (social distance: intimacy vs. strangeness) × 2 (symmetry of punishment: symmetric punishment vs. asymmetric punishment) within-subject design and showed that the cooperative behavior of participants decreased when the punishment option was added, and the two levels of symmetry and asymmetry were set. Specifically, compared with the symmetric punishment group, the asymmetric punishment group was more likely to choose a defection strategy and less likely to use a punishment strategy. Moreover, there was a marginal interaction effect between social distance and symmetry of punishment, and symmetry of punishment was a significant mediator in the relationship between social distance and individual cooperation. Specifically, asymmetric punishment reduced only the cooperation rate (CR) between participants and their friends. In conclusion, in dilemma situations, asymmetric reward did not influence individual cooperative behavior at different social distances, while asymmetric punishment did, because the sense of loss was more likely to awaken an individual's social comparison motives.
  5. Rafique S, Abdullah SM, Shahid MM, Ansari MO, Sulaiman K
    Sci Rep, 2017 01 13;7:39555.
    PMID: 28084304 DOI: 10.1038/srep39555
    This work demonstrates the high performance graphene oxide (GO)/PEDOT:PSS doubled decked hole transport layer (HTL) in the PCDTBT:PC71BM based bulk heterojunction organic photovoltaic device. The devices were tested on merits of their power conversion efficiency (PCE), reproducibility, stability and further compared with the devices with individual GO or PEDOT:PSS HTLs. Solar cells employing GO/PEDOT:PSS HTL yielded a PCE of 4.28% as compared to either of individual GO or PEDOT:PSS HTLs where they demonstrated PCEs of 2.77 and 3.57%, respectively. In case of single GO HTL, an inhomogeneous coating of ITO caused the poor performance whereas PEDOT:PSS is known to be hygroscopic and acidic which upon direct contact with ITO reduced the device performance. The improvement in the photovoltaic performance is mainly ascribed to the increased charge carriers mobility, short circuit current, open circuit voltage, fill factor, and decreased series resistance. The well matched work function of GO and PEDOT:PSS is likely to facilitate the charge transportation and an overall reduction in the series resistance. Moreover, GO could effectively block the electrons due to its large band-gap of ~3.6 eV, leading to an increased shunt resistance. In addition, we also observed the improvement in the reproducibility and stability.
  6. Woon CK, Jamal NAA, Noor MNIM, Abdullah SM, Ibrahim NM, Norman NH, et al.
    Anat Cell Biol, 2020 Sep 30;53(3):378.
    PMID: 32782237 DOI: 10.5115/acb.19.118e
  7. Woon CK, Jamal NAA, Noor MNIM, Abdullah SM, Mohamed Ibrahim N, Norman NH, et al.
    Anat Cell Biol, 2019 12;52(4):397-405.
    PMID: 31949978 DOI: 10.5115/acb.19.118
    Geometric morphometrics is a new approach for shape identification in diagnosis of malocclusion. Lateral cephalogram is an X-ray that taken for diagnosing malocclusion in dental setting. The aim of this study was to determine the differences of craniofacial shape in malocclusion by application of two-dimensional geometric morphometrics and to compile the database of malocclusion in adult Malaysian population. Lateral cephalogram radiographs of 381 adults Malaysia (age 18-45) were retrieved retrospectively and assigned to three groups according to their occlusion: class I, class II, and class III. The geometric morphometric shape study incorporated nine landmarks and was analyzed in details using tpsUtil p software. Geometric morphometric analysis such was done using MorphoJ software. The results of the principal component's analysis (PCA) yielded 14 main components responsible for 100% of the variation exhibited by the malocclusion with three highly significant PCA. The highest Mahalanobis distances were exhibited by the malocclusion class II and III population. The Procrustes ANOVA showed that the shape effect was highly significant (P<0.01). The discriminant function analysis showed the high percentage of 80% discriminate among the malocclusions after cross-validation. There are significant differences for ANB angle (A point-Nasion-B point) in all malocclusion groups. Class II has the widest ANB angle while class III has the most acute ANB angle. Skeletal shape was clearly associated with dental malocclusion and showed considerable variation. Geometric morphometrics is an alternative research tool and can be used for diagnosing individual classification of malocclusion.
  8. Abu Bakar AA, Zainuddin MZ, Abdullah SM, Tamchek N, Mohd Noor IS, Alauddin MS, et al.
    Polymers (Basel), 2022 Oct 25;14(21).
    PMID: 36365512 DOI: 10.3390/polym14214518
    The integration of additive manufacturing (3D printing) in the biomedical sector required material to portray a holistic characteristic in terms of printability, biocompatibility, degradability, and mechanical properties. This research aims to evaluate the 3D printability and mechanical properties of polyhydroxybutyrate (PHB) as additives in the urethane dimethacrylate (UDMA) based resin and its potential for medical applications. The printability of the PHB/UDMA resin blends was limited to 11 wt.% as it reached the maximum viscosity value at 2188 cP. Two-way analysis of variance (ANOVA) was also conducted to assess the significant effect of the varied PHB (wt.%) incorporation within UDMA resin, and the aging duration of 3D printed PHB/UDMA on mechanical properties in terms of tensile and impact properties. Meanwhile, the increasing crystallinity index (CI) of X-ray diffraction (XRD) in the 3D printed PHB/UDMA as the PHB loading increased, indicating that there is a strong correlation with the lower tensile and impact strength. FESEM images also proved that the agglomerations that occurred within the UDMA matrix had affected the mechanical performance of 3D printed PHB/UDMA. Nonetheless, the thermal stability of the 3D printed PHB/UDMA had only a slight deviation from the 3D printed UDMA since it had better thermal processability.
  9. Alwi SAK, Hisamuddin SN, Abdullah SM, Anuar A, Abdul Rahim AH, Majid SR, et al.
    Micromachines (Basel), 2021 Nov 11;12(11).
    PMID: 34832795 DOI: 10.3390/mi12111383
    In this work, we presented experimental observation on solution-processed bulk heterojunction organic photodiode using vanadyl 2,11,20,29-tetra tert-butyl 2,3 naphthalocyanine (VTTBNc) as a p-type material. VTTBNc is blended with two different acceptors, which are PC61BM and PC71BM, to offer further understanding in evaluating the performance in organic photodiode (OPD). The blend film of VTTBNc:PC71BM with a volumetric ratio of 1:1 exhibits optimized performance in the VTTBNc blend structure with 2.31 × 109 Jones detectivity and 26.11 mA/W responsivity at a -1 V bias. The response and recovery time of VTTBNc:PC71BM were recorded as 241 ms and 310 ms, respectively. The light absorption measurement demonstrated that VTTBNc could extend the light absorption to the near-infrared (NIR) region. The detail of the enhancement of the performance by adding VTTBNc to the blend was further explained in the discussion section.
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