Displaying publications 1 - 20 of 56 in total

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  1. Ab-Hamid N, Omar N, Ismail CAN, Long I
    World J Diabetes, 2023 Jun 15;14(6):795-807.
    PMID: 37383592 DOI: 10.4239/wjd.v14.i6.795
    There is growing evidence that diabetes can induce cognitive decline and dementia. It is a slow, progressive cognitive decline that can occur in any age group, but is seen more frequently in older individuals. Symptoms related to cognitive decline are worsened by chronic metabolic syndrome. Animal models are frequently utilized to elucidate the mechanisms of cognitive decline in diabetes and to assess potential drugs for therapy and prevention. This review addresses the common factors and pathophysiology involved in diabetes-related cognitive decline and outlines the various animal models used to study this condition.
  2. Abdullah S, Omar N, Yusoff SM, Obukwho EB, Nwunuji TP, Hanan L, et al.
    Springerplus, 2013;2:286.
    PMID: 23961386 DOI: 10.1186/2193-1801-2-286
    This study investigates the clinicopathological features of acute experimental streptococcosis in red tilapia using various routes of infection; intraperitoneal (IP), immersion (IM) and immersion cut (IC). Twenty four red tilapia in duplicates were inoculated intraperitoneally with 10(9) CFU/ml of S. agalactiae while another sets: intact, one with sharp cut at the tail end were exposed to bacterial inoculums 10(9) CFU/ml diluted in water while two groups of control fish were similarly manipulated. Clinical signs were recorded; samples from the gills, brain, eyes and kidneys were also taken for bacterial isolation and histopathology. Immunohistochemistry (IHC) and polymerase chain reaction (PCR) were employed to detect the antigen. The diseased fish showed skin, fin haemorrhages and exophthalmia with obvious signs in IP at 2 hpc followed by IC and IM at 4 hpc. The lesions were noticed earlier in the kidney and most severe in IP. IHC detected antigen as early as PCR and isolation with intense staining in blood vessel lumen and wall, macrophages in choroid, focal haemorrhage in the renal interstitium and meninges especially in IP followed by IC and IM. The immunolocalisation of the antigen described for the first time further explain the pathogenesis of streptococcosis in red tilapia.
  3. Abed SA, Tiun S, Omar N
    PLoS One, 2015;10(9):e0136614.
    PMID: 26422368 DOI: 10.1371/journal.pone.0136614
    Word Sense Disambiguation (WSD) is the task of determining which sense of an ambiguous word (word with multiple meanings) is chosen in a particular use of that word, by considering its context. A sentence is considered ambiguous if it contains ambiguous word(s). Practically, any sentence that has been classified as ambiguous usually has multiple interpretations, but just one of them presents the correct interpretation. We propose an unsupervised method that exploits knowledge based approaches for word sense disambiguation using Harmony Search Algorithm (HSA) based on a Stanford dependencies generator (HSDG). The role of the dependency generator is to parse sentences to obtain their dependency relations. Whereas, the goal of using the HSA is to maximize the overall semantic similarity of the set of parsed words. HSA invokes a combination of semantic similarity and relatedness measurements, i.e., Jiang and Conrath (jcn) and an adapted Lesk algorithm, to perform the HSA fitness function. Our proposed method was experimented on benchmark datasets, which yielded results comparable to the state-of-the-art WSD methods. In order to evaluate the effectiveness of the dependency generator, we perform the same methodology without the parser, but with a window of words. The empirical results demonstrate that the proposed method is able to produce effective solutions for most instances of the datasets used.
  4. Abu Bakar SH, Weatherley R, Omar N, Abdullah F, Mohamad Aun NS
    Health Soc Care Community, 2014 Mar;22(2):144-54.
    PMID: 24024495 DOI: 10.1111/hsc.12070
    This article presents the findings of a self-report study of the consequences of being an informal caregiver in Malaysia. The aim of this exploratory study was to examine Malaysian efforts in assisting informal caregivers, based on an analysis of the issues and concerns raised by the caregivers themselves. Data were obtained from a cross-sectional survey of informal caregivers in 2009. This sample comprised parents, spouses and/or adult siblings, and adult children, caring for their children, spouses or siblings and parents who were chronically ill and/or had a disability. Of 300 prospective participants, only 175 could be located (58%), but all those contacted agreed to participate. Respondents were randomly selected and interviewed using a structured questionnaire to identify the emotional, financial, social and physical issues consequent upon being a caregiver. Most respondents reported that their care-giving responsibilities had impacted their emotional, financial, social and/or physical well-being. Inadequate and/or uncertain income was by far the greatest concern followed in descending order by social, physical and emotional consequences. The one-way analysis of variance showed significant differences among the three categories of caregivers with respect to physical and emotional consequences. The findings show that care-giving has detrimental effects on the lives of informal caregivers, and that they are in significant need of social support to help them deal with care-giving tasks and responsibilities. Based on the findings, an integrated social support programme is proposed, tailored to the needs of informal caregivers.
  5. Abubakar SA, Isa MM, Omar N, Tan SW
    Mol Med Rep, 2020 Dec;22(6):4931-4937.
    PMID: 33174018 DOI: 10.3892/mmr.2020.11560
    The human ocular surface produces highly conserved cationic peptides. Human β‑defensins (HBDs) serve an important role in innate and adaptive immunity. They are primarily expressed in epithelial cells in response to infection and provide the first line of defence against invading microbes. Defensin β1 (DEFB1) is constitutively expressed and regulated by inflammatory mediators including interferon‑γ, lipopolysaccharide and peptidoglycans. DEFB4A is locally induced in response to microbial infection while DEFB109 is induced via Toll‑like receptor 2. The present study examined the expression of the HBD DEFB1, DEFB4A and DEFB109 genes in pterygium. The pterygium tissues and normal conjunctiva samples were obtained from 18 patients undergoing pterygium surgery. The reverse transcription‑quantitative polymerase chain reaction method was employed to determine the expression of DEFB1, DEFB4A and DEFB109 genes. The results revealed that the expression of DEFB1 and DEFB4A was significantly higher and upregulated in pterygium samples when compared with normal conjunctiva samples from each patient (P<0.05), while the expression of DEFB109 was observed to be lower in pterygium samples when compared with normal samples from the same patient. Previous studies have revealed that DEFB1 and DEFB4A genes are present in low concentrations inside the human eye, and they are upregulated during the maturation of keratinocytes, suggesting a possible role in cell differentiation. The DEFB109 gene is present in higher concentrations inside the human eye, though it is newly discovered. It has also been reported that DEFB1 may be involved in carcinogenesis epithelial tumours. Collectively, the current data suggests that HBDs may serve a crucial role in the pathogenesis and development of pterygia, and thus may be considered as novel molecular targets in understanding pterygia development.
  6. Agudosi ES, Abdullah EC, Numan A, Mubarak NM, Aid SR, Benages-Vilau R, et al.
    Sci Rep, 2020 Jul 08;10(1):11214.
    PMID: 32641769 DOI: 10.1038/s41598-020-68067-2
    Electrochemical stability of energy storage devices is one of their major concerns. Polymeric binders are generally used to enhance the stability of the electrode, but the electrochemical performance of the device is compromised due to the poor conductivity of the binders. Herein, 3D binder-free electrode based on nickel oxide deposited on graphene (G-NiO) was fabricated by a simple two-step method. First, graphene was deposited on nickel foam via atmospheric pressure chemical vapour deposition followed by electrodeposition of NiO. The structural and morphological analyses of the fabricated G-NiO electrode were conducted through Raman spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray spectroscopy (EDS). XRD and Raman results confirmed the successful growth of high-quality graphene on nickel foam. FESEM images revealed the sheet and urchin-like morphology of the graphene and NiO, respectively. The electrochemical performance of the fabricated electrode was evaluated through cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) in aqueous solution at room temperature. The G-NiO binder-free electrode exhibited a specific capacity of ≈ 243 C g-1 at 3 mV s-1 in a three-electrode cell. A two-electrode configuration of G-NiO//activated charcoal was fabricated to form a hybrid device (supercapattery) that operated in a stable potential window of 1.4 V. The energy density and power density of the asymmetric device measured at a current density of 0.2 A g-1 were estimated to be 47.3 W h kg-1 and 140 W kg-1, respectively. Additionally, the fabricated supercapattery showed high cyclic stability with 98.7% retention of specific capacity after 5,000 cycles. Thus, the proposed fabrication technique is highly suitable for large scale production of highly stable and binder-free electrodes for electrochemical energy storage devices.
  7. Ahmad R, Azman KF, Yahaya R, Shafin N, Omar N, Ahmad AH, et al.
    AIMS Neurosci, 2023;10(1):5-32.
    PMID: 37077958 DOI: 10.3934/Neuroscience.2023002
    This review aims to perform a bibliometric analysis of the research related to brain-derived neurotrophic factor (BDNF) in schizophrenia and offer suggestions for further work. Based on the keywords used, our study retrieved 335 documents for further analysis using a combination of three bibliometric techniques: co-word analysis, document co-citation analysis, and bibliographic coupling. A general rising trend in the number of publications was found in BDNF and schizophrenia research. Researchers from China and the United States have mostly researched BDNF and schizophrenia. Molecular Psychiatry is the most prestigious journal in the field of BDNF and schizophrenia research. The main topics and important research areas are cognition and the involvement of BDNF as a neurobiological marker (pathogenesis, therapy monitoring, and risk factors). Future research is anticipated to concentrate on relevant subjects, such as factors that affect BDNF levels or are connected to BDNF dysfunction in schizophrenia, as well as animal models of schizophrenia, in addition to cognition in schizophrenia.
  8. Al-Saffar A, Awang S, Tao H, Omar N, Al-Saiagh W, Al-Bared M
    PLoS One, 2018;13(4):e0194852.
    PMID: 29684036 DOI: 10.1371/journal.pone.0194852
    Sentiment analysis techniques are increasingly exploited to categorize the opinion text to one or more predefined sentiment classes for the creation and automated maintenance of review-aggregation websites. In this paper, a Malay sentiment analysis classification model is proposed to improve classification performances based on the semantic orientation and machine learning approaches. First, a total of 2,478 Malay sentiment-lexicon phrases and words are assigned with a synonym and stored with the help of more than one Malay native speaker, and the polarity is manually allotted with a score. In addition, the supervised machine learning approaches and lexicon knowledge method are combined for Malay sentiment classification with evaluating thirteen features. Finally, three individual classifiers and a combined classifier are used to evaluate the classification accuracy. In experimental results, a wide-range of comparative experiments is conducted on a Malay Reviews Corpus (MRC), and it demonstrates that the feature extraction improves the performance of Malay sentiment analysis based on the combined classification. However, the results depend on three factors, the features, the number of features and the classification approach.
  9. Alawiah A, Bauk S, Marashdeh MW, Nazura MZ, Abdul-Rashid HA, Yusoff Z, et al.
    Appl Radiat Isot, 2015 Oct;104:197-202.
    PMID: 26188687 DOI: 10.1016/j.apradiso.2015.07.011
    In regard to thermoluminescence (TL) applied to dosimetry, in recent times a number of researchers have explored the role of optical fibers for radiation detection and measurement. Many of the studies have focused on the specific dopant concentration, the type of dopant and the fiber core diameter, all key dependencies in producing significant increase in the sensitivity of such fibers. At doses of less than 1 Gy none of these investigations have addressed the relationship between dose response and TL glow peak behavior of erbium (Er)-doped silica cylindrical fibers (CF). For x-rays obtained at accelerating potentials from 70 to 130 kVp, delivering doses of between 0.1 and 0.7 Gy, present study explores the issue of dose response, special attention being paid to determination of the kinetic parameters and dosimetric peak properties of Er-doped CF. The effect of dose response on the kinetic parameters of the glow peak has been compared against other fiber types, revealing previously misunderstood connections between kinetic parameters and radiation dose. Within the investigated dose range there was an absence of supralinearity of response of the Er-doped silica CF, instead sub-linear response being observed. Detailed examination of glow peak response and kinetic parameters has thus been shown to shed new light of the rarely acknowledged issue of the limitation of TL kinetic model and sub-linear dose response of Er-doped silica CF.
  10. Ali, M. H., Ismail, A., Alam, S. S., Makhbul, Z. M., Omar, N. A.
    MyJurnal
    The aim of this paper is to revisit the theory of planned behaviour (TPB) in relation to the halal food market, specifically in the context of the Cadbury scandal. The present survey (with 132 respondents) replicates the original study of TPB in the context of halal food, done before the scandal, and the results are compared. We rationalize the differences, and assess the impact of the halal scandal on consumer purchasing behaviour. In doing so, we validate the impact of a food scandal in terms of the purchasing intentions of halal customers under a new (post-scandal) condition of uncertainty. The results provide in-depth insights into halal purchasing behaviour and are intended to be used: (a) to increase the understanding of the impact of a food scandal on purchasing behaviour, (b) to clarify whether a food scandal has a real effect on customers, and (c) to ascertain whether the determinants of purchasing intention are similar before and after a food scandal.
  11. Aziz CB, Omar N, Abdullah WZ, Jalil RA, Nik WS, Zakaria R
    N Am J Med Sci, 2014 Aug;6(8):377-82.
    PMID: 25210670 DOI: 10.4103/1947-2714.139286
    Obese subjects are at risk of multiple comorbidities including stroke and coronary heart disease (CHD), which is partly due to disturbances in the hemostatic system.
  12. Eleazu C, Omar N, Lim OZ, Yeoh BS, Nik Hussain NH, Mohamed M
    Front Physiol, 2019 08 07;10:1017.
    PMID: 31417435 DOI: 10.3389/fphys.2019.01017
    [This corrects the article DOI: 10.3389/fphys.2019.00787.].
  13. Eleazu C, Omar N, Lim OZ, Yeoh BS, Nik Hussain NH, Mohamed M
    Front Physiol, 2019;10:787.
    PMID: 31293451 DOI: 10.3389/fphys.2019.00787
    Obesity, a chronic multifaceted disease, predisposes its patients to increased risk of metabolic disorders such as: diabetes mellitus, cardiovascular diseases, dyslipidemia, etc. Recent studies reported it to be amongst the leading causes of deaths in the world. Although several treatment options for obesity abound, many of them have not been able to successfully reverse the existing obesity and metabolic dysregulation. This has therefore warranted the need for either alternative therapies or diversification of the treatment approach for obesity and its comorbidity. When the receptor for advanced glycation end products (RAGE) interacts with its ligand, RAGE-ligand activates an inflammatory signaling cascade, that leads to the activation of nuclear factor kappa B (NF-κB) and transcription of inflammatory cytokines. This action has been associated with the development of obesity and its mediated metabolic dysregulation. In view of the increasing prevalence of obesity globally and the potential threat it places on life expectancy, this article reviewed the promising potentials of targeting endogenous secretory receptor for advanced glycation end products/soluble receptors for advanced glycation end products signaling as a treatment approach for obesity. We carried out a literature search in several electronic data bases such as: Pubmed, Pubmed Central, Google, Google Scholar, Scopus, and Medline from 1980 to 2019 to acquire the status of information concerning this. The article suggests the need for the development of an esRAGE/sRAGE targeted pharmacotherapy as a treatment approach for obesity and its comorbidity.
  14. Fijasri NH, Muhammad Asri NA, Mohd Shah MS, Abd Samad MR, Omar N
    Afr J Paediatr Surg, 2023;20(3):245-248.
    PMID: 37470566 DOI: 10.4103/ajps.AJPS_10_21
    Congenital pulmonary airway malformation (CPAM) together with oesophageal atresia and tracheoesophageal fistula (TOF) is a very rare condition in neonates. We presented a case of an infant with Gross type C oesophageal atresia with TOF coexisting with Stocker Type III CPAM in our centre. It is interesting to know that TOF associated with type III CPAM has never been reported in the literature. The child was delivered through caesarean section, and because of respiratory distress post-delivery, endotracheal intubation was carried out immediately. CPAM was diagnosed by a suspicious finding from the initial chest X-ray and the diagnosis was confirmed through computed tomography scan of the chest. The patient was initially stabilised in a neonatal intensive care unit (NICU), and after the successful ligation of fistula and surgical repair of TOF, lung recruitment was started by high flow oscillatory ventilation. The patient recovered well without complications and able to maintain good saturation without oxygen support through the stay in the neonatal unit. Early recognition of this rare association is essential for immediate transfer to NICU, the intervention of any early life-threatening complications, and for vigilant monitoring in the postoperative period.
  15. Hadie SNH, Tan VPS, Omar N, Nik Mohd Alwi NA, Lim HL, Ku Marsilla KI
    Front Med (Lausanne), 2021;8:739238.
    PMID: 34671622 DOI: 10.3389/fmed.2021.739238
    This study explored the impact of online lectures that were developed using principles of cognitive load theory (CLT) and cognitive theory of multimedia learning (CTML) on health profession students' lecture comprehension, cognitive load, cognitive engagement, and intrinsic motivation in learning. A total of 215 first-year undergraduate students in medical, dentistry, and nutrition programs participated in this pre-post quasi experimental study. The students attended a typical face-to-face lecture on Day-1 of the intervention, followed by a CLT-based online lecture 8 weeks thereafter. Their comprehension of the lecture topics was measured through pre- and post-lecture assessments, and their cognitive load, cognitive engagement, and motivation were measured immediately after each lecture session. The analysis revealed that the CLT-based online lectures promoted the students' comprehension of the lecture content (p < 0.001), self-perceived learning (p < 0.001), engagement toward the learning material, and motivation to learn (p = 0.025). It was also effective at reducing the students' intrinsic and extraneous cognitive loads (p < 0.001). Hence, designing online lectures using CLT and CTML principles could be an effective method to promote students' knowledge and comprehension, cognitive engagement, and learning motivation. However, further research is needed to investigate the applicability and impact of CLT-based online lectures in non-health profession disciplines.
  16. Lee OZJ, Omar N, Tay JK, Lee VKM
    Cancers (Basel), 2023 Nov 24;15(23).
    PMID: 38067267 DOI: 10.3390/cancers15235563
    The Epstein-Barr virus (EBV) is associated with various tumor types, including nasopharyngeal carcinoma and lymphoproliferative disorders. While much is known about EBV-related epithelial and lymphoid tumors, there is a paucity of knowledge concerning EBV-associated mesenchymal tumors. This review aims to provide a comprehensive overview of EBV-associated mesenchymal tumors, encompassing their clinical features, pathological characteristics, pathophysiology, prognostic factors, and current treatment approaches. Through an extensive literature search using the PubMed database, we were able to identify three distinct EBV-associated mesenchymal tumors: EBV-associated smooth muscle tumors, inflammatory pseudotumor-like follicular dendritic cell sarcomas, and EBV-associated osteosarcomas. Although this review extensively explored the different aspects of these mesenchymal tumors, our comprehension of the underlying pathophysiology in this context is still incomplete. Therefore, we hope that this review paper will not only serve as a valuable repository of information but also serve as a catalyst for prospective in vitro and in vivo research studies to bridge the existing knowledge gap surrounding pathophysiology, ultimately making an important contribution to shaping future therapeutic approaches.
  17. Lee PY, Yeoh Y, Omar N, Pung YF, Lim LC, Low TY
    Crit Rev Clin Lab Sci, 2021 11;58(7):513-529.
    PMID: 34615421 DOI: 10.1080/10408363.2021.1942781
    Matrix-assisted laser desorption/ionization (MALDI) imaging is an emergent technology that has been increasingly adopted in cancer research. MALDI imaging is capable of providing global molecular mapping of the abundance and spatial information of biomolecules directly in the tissues without labeling. It enables the characterization of a wide spectrum of analytes, including proteins, peptides, glycans, lipids, drugs, and metabolites and is well suited for both discovery and targeted analysis. An advantage of MALDI imaging is that it maintains tissue integrity, which allows correlation with histological features. It has proven to be a valuable tool for probing tumor heterogeneity and has been increasingly applied to interrogate molecular events associated with cancer. It provides unique insights into both the molecular content and spatial details that are not accessible by other techniques, and it has allowed considerable progress in the field of cancer research. In this review, we first provide an overview of the MALDI imaging workflow and approach. We then highlight some useful applications in various niches of cancer research, followed by a discussion of the challenges, recent developments and future prospect of this technique in the field.
  18. Loh Q, Omar N, Glökler J, Lim TS
    Anal Biochem, 2014 Oct 15;463:67-9.
    PMID: 24972268 DOI: 10.1016/j.ab.2014.06.012
    Immunoassays are often coupled to peroxidase activity for antigen detection. Sensitivity and speed of detection has been increased by the advent of hybrid methods such as immuno-PCR (polymerase chain reaction). However, a more simplified immunoassay that retains both colorimetric peroxidase detection and effective DNA amplification in a setting closer to field application conditions has been nonexistent. Here we describe a method that successfully combines a competitive immunoassay with the new isothermal quadruplex-primed amplification (QPA) to generate excess quadruplex reporter molecules with intrinsic peroxidase DNAzyme activity.
  19. Lokanathan Y, Omar N, Ahmad Puzi NN, Saim A, Hj Idrus R
    Malays J Med Sci, 2016 Jan;23(1):4-14.
    PMID: 27540320 MyJurnal
    Centella asiatica, locally well known in Malaysia as pegaga, is a traditional herb that has been used widely in Ayurvedic medicine, traditional Chinese medicine, and in the traditional medicine of other Southeast Asian countries including Malaysia. Although consumption of the plant is indicated for various illnesses, its potential neuroprotective properties have been well studied and documented. In addition to past studies, recent studies also discovered and/or reconfirmed that C. asiatica acts as an antioxidant, reducing the effect of oxidative stress in vitro and in vivo. At the in vitro level, C. asiatica promotes dendrite arborisation and elongation, and also protects the neurons from apoptosis. In vivo studies have shown that the whole extract and also individual compounds of C. asiatica have a protective effect against various neurological diseases. Most of the in vivo studies on neuroprotective effects have focused on Alzheimer's disease, Parkinson's disease, learning and memory enhancement, neurotoxicity and other mental illnesses such as depression and anxiety, and epilepsy. Recent studies have embarked on finding the molecular mechanism of neuroprotection by C. asiatica extract. However, the capability of C. asiatica in enhancing neuroregeneration has not been studied much and is limited to the regeneration of crushed sciatic nerves and protection from neuronal injury in hypoxia conditions. More studies are still needed to identify the compounds and the mechanism of action of C. asiatica that are particularly involved in neuroprotection and neuroregeneration. Furthermore, the extraction method, biochemical profile and dosage information of the C. asiatica extract need to be standardised to enhance the economic value of this traditional herb and to accelerate the entry of C. asiatica extracts into modern medicine.
  20. Low TY, Mohtar MA, Lee PY, Omar N, Zhou H, Ye M
    Mass Spectrom Rev, 2021 07;40(4):309-333.
    PMID: 32491218 DOI: 10.1002/mas.21636
    Phosphorylation is a form of protein posttranslational modification (PTM) that regulates many biological processes. Whereas phosphoproteomics is a scientific discipline that identifies and quantifies the phosphorylated proteome using mass spectrometry (MS). This task is extremely challenging as ~30% of the human proteome is phosphorylated; and each phosphoprotein may exist as multiple phospho-isoforms that are present in low abundance and stoichiometry. Hence, phosphopeptide enrichment techniques are indispensable to (phospho)proteomics laboratories. These enrichment methods encompass widely-adopted techniques such as (i) affinity-based chromatography; (ii) ion exchange and mixed-mode chromatography (iii) enrichment with phospho-specific antibodies and protein domains, and (iv) functionalized polymers and other less common but emerging technologies such as hydroxyapatite chromatography and precipitation with inorganic ions. Here, we review these techniques, their history, continuous development and evaluation. Besides, we outline associating challenges of phosphoproteomics that are linked to experimental design, sample preparation, and proteolytic digestion. In addition, we also discuss about the future outlooks in phosphoproteomics, focusing on elucidating the noncanonical phosphoproteome and deciphering the "dark phosphoproteome". © 2020 John Wiley & Sons Ltd.
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