Displaying publications 1 - 20 of 57 in total

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  1. Lim A, Chew JJ, Ngu LH, Ismadji S, Khaerudini DS, Sunarso J
    ACS Omega, 2020 Nov 10;5(44):28673-28683.
    PMID: 33195920 DOI: 10.1021/acsomega.0c03811
    Oil palm trunk (OPT) represents one of the five main oil palm biomass wastes with high carbon content that can be economically converted to a large surface area, porous activated carbon (AC) adsorbent to treat palm oil mill effluent wastewater in Indonesia and Malaysia. In the first portion of this work, the design of the experiment was used to determine the optimum set of synthesis parameters required to maximize the iodine number of AC [i.e., Brunauer-Emmett-Teller (BET) specific surface area indicator] prepared from OPT via chemical activation route using H3PO4. The iodine numbers of AC and AC yield were probed as the impregnation ratio, the activation time, and the activation temperature were varied in the range of 0.28-3.47, 5.68-69.32 min, and 379-521 °C, respectively. An impregnation ratio of 2.29, an activation time of 6 min, and an activation temperature of 450 °C were identified as the optimum set of synthesis parameters. In the second portion of the work, the AC synthesized using the optimum parameters were then characterized and tested as an adsorbent for tannin. N2 sorption results revealed that the AC exhibits type IV isotherm, that is, contains micropores and mesopores and displays a relatively high BET specific surface area of 1657 m2 g-1. Adsorption equilibria isotherms for tannin adsorption onto the AC were collected at three different pH of 2, 4, and 6 and were nonlinearly fitted using Langmuir and Freundlich isotherm models, where the Langmuir isotherm gave better fitting than Freundlich. The higher adsorption capacity at lower pH can be explained in terms of the absence of electrostatic repulsion interaction between the AC surface and the tannic acid species as suggested by the point of zero charges (pHpzc) of 4.8 and an increasing ionization of tannic acid with pH rise between 4 and 7. Adsorption kinetics data were also obtained at four different pH of 2, 4, 6, and 8 where the nonlinear pseudo-first-order model best fitted the kinetic at pH of 2 and the nonlinear pseudo-second-order model represented the kinetic best at the remaining higher pH, which suggests that tannin adsorption onto AC occurred by physisorption at pH of 2 and by chemisorption at pH of 4, 6, and 8.
  2. Lim A, Tan D, Price P, Kamarulzaman A, Tan HY, James I, et al.
    AIDS, 2007 Jul 31;21(12):1525-34.
    PMID: 17630546
    To examine the relationships between blood CD4 natural regulatory T (Treg) cells, plasma HIV RNA level, CD4 T-cell count and immune activation in untreated HIV-infected patients and immunodeficient patients beginning antiretroviral therapy (ART), using a novel phenotype to define Treg cells (CD25CD127CD4). Data were compared with established Treg cell markers (FoxP3, CTLA-4 and GITR).
  3. Eng V, Lim A, Janssen SMJ, Satel J
    Acta Psychol (Amst), 2018 Feb;183:51-57.
    PMID: 29328938 DOI: 10.1016/j.actpsy.2017.12.011
    Studies of endogenous and exogenous attentional orienting in spatial cueing paradigms have been used to investigate inhibition of return, a behavioral phenomenon characterized by delayed reaction time in response to recently attended locations. When eye movements are suppressed, attention is covertly oriented to central or peripheral stimuli. Overt orienting, on the other hand, requires explicit eye movements to the stimuli. The present study examined the time course of slowed reaction times to previously attended locations when distractors are introduced into overt and covert orienting tasks. In a series of experiments, manual responses were required to targets following central and peripheral cues at three different cue-target intervals, with and without activated oculomotor systems. The results demonstrate that, when eye movements are suppressed, behavioral inhibition is reduced or delayed in magnitude by the presence of a distractor relative to conditions without distractors. However, the time course of behavioral inhibition when eye movements are required remains similar with or without distractors.
  4. Bermeitinger C, Kalbfleisch L, Schäfer K, Lim A, Goymann H, Reuter L, et al.
    Adv Cogn Psychol, 2020;16(2):131-149.
    PMID: 32665804 DOI: 10.5709/acp-0291-y
    Response priming refers to the finding that a prime preceding a target influences the response to the target. With German subjects, horizontally moving dots as primes, and static arrows as targets, there are typically faster responses to compatible (i.e., prime and target are associated with the same response) as compared to incompatible targets (i.e., positive compatibility effect, PCE) with short stimulus onset asynchronies (SOAs). In contrast, with longer SOAs, subjects respond faster to incompatible as compared to compatible targets (i.e., negative compatibility effect, NCE). In the present study, we extended the evidence by adding vertically oriented materials. Furthermore, we tested subjects from Malaysia and Japan, where the vertical orientation is more present in daily life, and compared them to German subjects to investigate whether the amount of experience with one orientation influences the compatibility effects on this orientation. Overall, we found pronounced PCEs in the short SOA (i.e., 150 ms) but only reduced PCEs in the longer SOAs (i.e., 350, 550, and 750 ms) across all countries and orientations. There were no differences between the German and Malaysian samples, but the Japanese sample showed larger PCEs in the longer SOAs compared to both other samples. Furthermore, we found larger PCEs for horizontal than vertical materials in the short SOA and larger PCEs for vertical than horizontal materials in the longer SOAs. We discuss our findings in light of theories and findings on compatibility effects as well as attentional mechanisms.
  5. Lim AS, Ang BC, Heng LK, Hart PM, Ngui MS, Chew P, et al.
    Ann Acad Med Singap, 1989 Mar;18(2):174-7.
    PMID: 2751233
    This is a retrospective study of 525 posterior chamber implants in diabetics performed by A S M Lim and B C Ang of Singapore. The patients were reviewed by visiting ophthalmologists--J E Kennedy (Sydney), M Ngui (East Malaysia) and P M Hart (Belfast). This study did not show any significant difference in the complication of post-operative visual acuity between diabetics and non-diabetics. 95% obtained 6/12 vision or better when pre-existing disease was excluded. It also showed that posterior chamber implants can be inserted in eyes with maculopathy or proliferative retinopathy if laser treatment was effectively done before or after surgery.
  6. Giam YC, Tham SN, Tan T, Lim A
    Ann Acad Med Singap, 1986 Jan;15(1):118-21.
    PMID: 2939787
    Drug eruptions from indeginous medicine is often difficult to diagnosis and confirm. It is known that a number of these now supplied by bomohs and Chinese sinsehs contain known drugs and are dispensed as tablets and capsules. We report 3 cases of adverse drug eruption to "Jamu", a Malay herb. A particular brand, "Jamu Indonesia, Toko Air Pancur", from Johor Bahru, Malaysia, is especially recommended for "sakit pinggang" or backache. The cases occurred between January and February 1985, and all had taken brown kidney shaped tablets. The adverse reactions were moderately severe. Two had erythroderma with hepatitis, and one, Steven Johnson Syndrome. Analysis of this jamu for analgesics led to the discovery of adulteration with phenylbutazone and diazepam. Records from local cases from 1974-1984 showed that 8 other patients, all Chinese had adverse cutaneous eruptions from phenylbutazone, oxybutazone and propyphenazone. The skin manifestations were erythroderma (2 cases), vasculitis (2 cases) and toxic epidermal necrolysis (4 cases). Those with toxic epidermal necrolysis had 100% mortality.
  7. Wong WM, Tham YC, Simunovic MP, Chen FK, Luu CD, Chen H, et al.
    Asia Pac J Ophthalmol (Phila), 2024;13(1):100030.
    PMID: 38233300 DOI: 10.1016/j.apjo.2023.100030
    PURPOSE: There are major gaps in our knowledge of hereditary ocular conditions in the Asia-Pacific population, which comprises approximately 60% of the world's population. Therefore, a concerted regional effort is urgently needed to close this critical knowledge gap and apply precision medicine technology to improve the quality of lives of these patients in the Asia-Pacific region.

    DESIGN: Multi-national, multi-center collaborative network.

    METHODS: The Research Standing Committee of the Asia-Pacific Academy of Ophthalmology and the Asia-Pacific Society of Eye Genetics fostered this research collaboration, which brings together renowned institutions and experts for inherited eye diseases in the Asia-Pacific region. The immediate priority of the network will be inherited retinal diseases (IRDs), where there is a lack of detailed characterization of these conditions and in the number of established registries.

    RESULTS: The network comprises 55 members from 35 centers, spanning 12 countries and regions, including Australia, China, India, Indonesia, Japan, South Korea, Malaysia, Nepal, Philippines, Singapore, Taiwan, and Thailand. The steering committee comprises ophthalmologists with experience in consortia for eye diseases in the Asia-Pacific region, leading ophthalmologists and vision scientists in the field of IRDs internationally, and ophthalmic geneticists.

    CONCLUSIONS: The Asia Pacific Inherited Eye Disease (APIED) network aims to (1) improve genotyping capabilities and expertise to increase early and accurate genetic diagnosis of IRDs, (2) harmonise deep phenotyping practices and utilization of ontological terms, and (3) establish high-quality, multi-user, federated disease registries that will facilitate patient care, genetic counseling, and research of IRDs regionally and internationally.

  8. Sam CK, Kesavan-Padmaja, Liam CK, Soon SC, Lim AL, Ong EK
    Asian Pac J Allergy Immunol, 1998 Mar;16(1):1-4.
    PMID: 9681122
    In this paper we report results of skin prick tests (SPT) using pollen extracts on 200 patients with clinical symptoms of asthma, and results of a parallel study in which pollen was collected and classified over a period of 18 months. The patients were outpatients from the University Hospital in Kuala Lumpur, Malaysia, while the pollen grains were collected with a spore trap placed in the campus of the University of Malaya, approximately one kilometer from the University Hospital. Pollen extracts of 3 grasses (Bahia, Bermuda, rough pigweed) and 2 flowering trees, Acacia and Melaleuca, were used in the SPT. Of the 29.5% asthmatics with positive SPT reactions, 21.5% were to one or more of the grass pollens, 21.5% to Acacia and 7.5% to Melaleuca pollen. Acacia and Bermuda grass extracts were the most allergenic, which agreed with results of the pollen collection which showed grass and Acacia pollen grains to be the two most commonly found pollens.

    Study site: University Malaya Medical Centre (UMMC)
  9. Eng V, Lim A, Kwon S, Gan SR, Jamaluddin SA, Janssen SMJ, et al.
    Atten Percept Psychophys, 2017 May;79(4):1097-1106.
    PMID: 28229429 DOI: 10.3758/s13414-017-1295-8
    There are thought to be two forms of inhibition of return (IOR) depending on whether the oculomotor system is activated or suppressed. When saccades are allowed, output-based IOR is generated, whereas input-based IOR arises when saccades are prohibited. In a series of 4 experiments, we mixed or blocked compatible and incompatible trials with saccadic or manual responses to investigate whether cueing effects would follow the same pattern as those observed with more traditional peripheral onsets and central arrows. In all experiments, an uninformative cue was displayed, followed by a cue-back stimulus that was either red or green, indicating whether a compatible or incompatible response was required. The results showed that IOR was indeed observed for compatible responses in all tasks, whereas IOR was eliminated for incompatible trials-but only with saccadic responses. These findings indicate that the dissociation between input- and output-based forms of IOR depends on more than just oculomotor activation, providing further support for the existence of an inhibitory cueing effect that is distinct to the manual response modality.
  10. Lim A, O'Brien B, Onnis L
    Behav Res Methods, 2024 Mar;56(3):1283-1313.
    PMID: 37553536 DOI: 10.3758/s13428-023-02094-5
    Research on orthographic consistency in English words has selectively identified different sub-syllabic units in isolation (grapheme, onset, vowel, coda, rime), yet there is no comprehensive assessment of how these measures affect word identification when taken together. To study which aspects of consistency are more psychologically relevant, we investigated their independent and composite effects on human reading behavior using large-scale databases. Study 1 found effects on adults' naming responses of both feedforward consistency (orthography to phonology) and feedback consistency (phonology to orthography). Study 2 found feedback but no feedforward consistency effects on visual and auditory lexical decision tasks, with the best predictor being a composite measure of consistency across grapheme, rime, OVC, and word-initial letter-phoneme. In Study 3, we explicitly modeled the reading process with forward and backward flow in a bidirectionally connected neural network. The model captured latent dimensions of quasi-regular mapping that explain additional variance in human reading and spelling behavior, compared to the established measures. Together, the results suggest interactive activation between phonological and orthographic word representations. They also validate the role of computational analyses of language to better understand how print maps to sound, and what properties of natural language affect reading complexity.
  11. Onnis L, Lim A, Cheung S, Huettig F
    Cogn Sci, 2022 Oct;46(10):e13201.
    PMID: 36240464 DOI: 10.1111/cogs.13201
    Prediction is one characteristic of the human mind. But what does it mean to say the mind is a "prediction machine" and inherently forward looking as is frequently claimed? In natural languages, many contexts are not easily predictable in a forward fashion. In English, for example, many frequent verbs do not carry unique meaning on their own but instead, rely on another word or words that follow them to become meaningful. Upon reading take a the processor often cannot easily predict walk as the next word. But the system can "look back" and integrate walk more easily when it follows take a (e.g., as opposed to *make|get|have a walk). In the present paper, we provide further evidence for the importance of both forward and backward-looking in language processing. In two self-paced reading tasks and an eye-tracking reading task, we found evidence that adult English native speakers' sensitivity to word forward and backward conditional probability significantly predicted reading times over and above psycholinguistic predictors of reading latencies. We conclude that both forward and backward-looking (prediction and integration) appear to be important characteristics of language processing. Our results thus suggest that it makes just as much sense to call the mind an "integration machine" which is inherently backward 'looking.'
  12. Lim A, Janssen SMJ, Satel J
    Cogn Affect Behav Neurosci, 2020 12;20(6):1349-1364.
    PMID: 33236297 DOI: 10.3758/s13415-020-00846-w
    Inhibition of return is characterized by delayed responses to previously attended locations when the interval between stimuli is long enough. The present study employed steady-state visual evoked potentials (SSVEPs) as a measure of attentional modulation to explore the nature and time course of input- and output-based inhibitory cueing mechanisms that each slow response times at previously stimulated locations under different experimental conditions. The neural effects of behavioral inhibition were examined by comparing post-cue SSVEPs between cued and uncued locations measured across two tasks that differed only in the response modality (saccadic or manual response to targets). Grand averages of SSVEP amplitudes for each condition showed a reduction in amplitude at cued locations in the window of 100-500 ms post-cue, revealing an early, short-term decrease in the responses of neurons that can be attributed to sensory adaptation, regardless of response modality. Because primary visual cortex has been found to be one of the major sources of SSVEP signals, the results suggest that the SSVEP modulations observed were caused by input-based inhibition that occurred in V1, or visual areas earlier than V1, as a consequence of reduced visual input activity at previously cued locations. No SSVEP modulations were observed in either response condition late in the cue-target interval, suggesting that neither late input- nor output-based IOR modulates SSVEPs. These findings provide further electrophysiological support for the theory of multiple mechanisms contributing to behavioral cueing effects.
  13. Janssen SMJ, Foo A, Johnson SN, Lim A, Satel J
    Conscious Cogn, 2021 03;89:103089.
    PMID: 33607423 DOI: 10.1016/j.concog.2021.103089
    To examine the relationship between visual imagery and autobiographical memory, eye position and pupil size were recorded while participants first searched for memories and then reconstructed the retrieved memories (Experiment 1), or only searched for memories (Experiment 2). In Experiment 1, we observed that, although recollective experience was not associated with the number of fixations per minute, memories that took longer to retrieve were linked to increased pupil size. In Experiment 2, we observed that directly retrieved memories were recalled more quickly and were accompanied by smaller pupils than generatively retrieved memories. After correcting for response time, retrieval mode also produced an effect, showing that decreased pupil size is not simply due to directly retrieved memories being recalled more quickly. These findings provide compelling evidence that objective measures, such as pupil size, can be used alongside subjective measures, such as self-reports, to distinguish between directly retrieved and generatively retrieved memories.
  14. Singh H, Mohammed AH, Stokes E, Malone D, Turner J, Hassan BAR, et al.
    Curr Pharm Teach Learn, 2024 Jan;16(1):69-76.
    PMID: 38158327 DOI: 10.1016/j.cptl.2023.12.007
    BACKGROUND AND PURPOSE: This study aimed to evaluate an accelerated dispensing course for graduate entry (GE) pharmacy students with prior science-related degrees to join undergraduate (UG) students in year three of the Monash Pharmacy degree.

    EDUCATIONAL ACTIVITY AND SETTING: A one day accelerated dispensing course using MyDispense software was delivered to 59 GE students. The accelerated dispensing course was identical to the standard three-week dispensing course delivered to UG students. The same assessment of dispensing skills was conducted after course completion for both UG and GE students and included dispensing four prescriptions of varying difficulty. The assessment scores of the UG and GE students were compared. Perception data from the accelerated course were also collected.

    FINDINGS: The accelerated dispensing curriculum was well received by students. They found the simulation relevant to practice, easy to navigate, and helpful for preparing them for assessment. Overall, 5.1% of GE students failed the assessment, which was lower than the 32.6% failure rate in the UG cohort. Comparison of assessment grades between UG and GE students showed no notable disadvantage to attainment of learning outcomes with the accelerated curriculum. However, UG students were more likely to provide unsafe instructions compared to GE students in their labeling for three out of four prescriptions.

    SUMMARY: An accelerated dispensing curriculum can be effectively delivered to mature learners with a prior science-related degree as no notable deficiencies were identified when comparing the assessment results of GE students against UG students when both student cohorts undertook the same dispensing assessment.

  15. Krishnan S, Blebil AQ, Dujaili JA, Chuang S, Lim A
    PMID: 37361790 DOI: 10.1007/s10639-023-11745-1
    As we enter a world of blended learning in higher education, an increased need for adaptation of teaching strategies to enhance engagement has been recognised to amplify learning outcomes online. Gamification has been identified as a creative tool to engage the current cohort of learners who are also characteristically tech-savvy. To this end, escape room games have gained considerable traction in medical and pharmacy education to promote learning, critical thinking and teamwork. In this pilot study we describe the implementation of a 60-minute, web-based hepatitis-themed escape room game within a Year 3 Pharmacotherapy unit at Monash University. A total of 418 students participated in this activity. Students' knowledge gain on the topic was assessed through a pre- and post-intervention assessment, whereby a statistically significant improvement was seen in the knowledge score following implementation of the gaming activity (58.66% pre-intervention vs. 72.05% post-intervention, p 
  16. Ramli N, Merican AM, Lim A, Kumar G
    Eur Radiol, 2001;11(10):2011-4.
    PMID: 11702136
    Brown-Sequard syndrome (BSS) is a unilateral cord injury characterised by an ipsilateral motor deficit with contralateral pain and temperature hypoaesthesia. Although there are a variety of causes, the majority of cases are generally of neoplastic origin or are traumatic in origin. We describe a rare cause of Brown-Sequard syndrome as a result of post-traumatic arachnoiditis. Magnetic resonance imaging with the use of thin-slice high-resolution constructive interference in steady state (CISS) and T2-weighted spin-echo sequence were used to demonstrate the cause and appearance of the lesion in the spinal canal and was useful in the assessment and management of the patient. This case illustrates the usefulness of the CISS sequence in MRI for elucidating arachnoiditis.
  17. Lim A, Eng V, Janssen SMJ, Satel J
    Exp Brain Res, 2018 05;236(5):1369-1382.
    PMID: 29520444 DOI: 10.1007/s00221-018-5225-3
    Inhibition of return (IOR) refers to an increase in reaction times to targets that appeared at a previously cued location relative to an uncued location, often investigated using a spatial cueing paradigm. Despite numerous studies that have examined many aspects of IOR, the neurophysiological mechanisms underlying IOR are still in dispute. The objective of the current research is to investigate the plausible mechanisms by manipulating the cue and target types between central and peripheral stimuli in a traditional cue-target paradigm with saccadic responses to targets. In peripheral-cueing conditions, we observed inhibitory cueing effects across all cue-target onset asynchronies (CTOAs) with peripheral targets, but IOR was smaller and arose later with central targets. No inhibition was observed in central-cueing conditions at any CTOAs. Empirical data were simulated using a two-dimensional dynamic neural field model. Our results and simulations support previous work demonstrating that, at short CTOAs, behavioral inhibition is only observed with repeated stimulation-an effect of sensory adaptation. With longer CTOAs, IOR is observed regardless of target type when peripheral cueing is used. Our findings suggest that behaviorally exhibited inhibitory cueing effects can be attributed to multiple mechanisms, including both attenuation of visual stimulation and local inhibition in the superior colliculus.
  18. Xin RKW, Yee TW, Qin WZ, Kaiyee L, Mohammed AH, Blebil A, et al.
    Explor Res Clin Soc Pharm, 2024 Mar;13:100410.
    PMID: 38389828 DOI: 10.1016/j.rcsop.2024.100410
    BACKGROUND: The utilization of vitamins and dietary supplements (DSs) among consumers in Malaysia has seen a notable increase. However, there is limited research available on how pharmacists in Eastern countries manage the provision of these products.

    OBJECTIVE: This study aims to assess the knowledge, attitudes, and practices of community pharmacists in Malaysia regarding the provision of counselling services on vitamins and DSs. The findings will inform education strategies in this area.

    METHODS: A cross-sectional quantitative study was conducted from February to April 2022 using a validated online-based questionnaire. The survey was distributed to community pharmacists across Malaysia through social media channels. t-test and ANOVA test were used for data analysis.

    RESULTS: Among the 260 participants, 73.5% were categorized as having average product knowledge. Key concerns included a lack of knowledge about the indications of new products and when to discontinue their use. Regarding dosing in specific patient groups, 33.5% of pharmacists only occasionally consulted references and primarily relied on product labels. Furthermore, 29% of pharmacists believed it was unnecessary to refer patients to doctors when they experienced ongoing symptoms while taking vitamins or DSs. Interestingly, 44.6% of pharmacists believed there was a correlation between the efficacy of vitamins and their price, often recommending more expensive brands despite similar content.

    CONCLUSION: There is an opportunity to enhance the knowledge of pharmacists in Malaysia regarding vitamins and DSs. Education interventions should focus on areas such as dosing for specific patient groups, when to discontinue products, understanding new products, evidence-based efficacy of products for specific conditions, and providing a framework for appropriate referral to support pharmacists in their practice.

  19. Ong YQ, Lim A, Park HR, Harrison E, McConnell G, Lee J, et al.
    Folia Phoniatr Logop, 2024 Jan 08.
    PMID: 38190816 DOI: 10.1159/000536112
    INTRODUCTION: Attitudes of speech-language pathologists (SLPs) toward stuttering play an important role in managing stuttering cases. Yet, such studies had not been studied in Malaysia, a country that is still developing the profession of speech-language pathology. This study aimed to explore the attitudes of Malaysian SLPs and speech-language pathology students toward stuttering.

    METHODS: A total of 50 SLPs and 67 speech-language pathology students completed the Clinician Attitudes Towards Stuttering (CATS) inventory. There were eight domains of attitudes toward stuttering: (a) etiology, (b) early intervention, (c) therapeutic efficacy, (d) personalities of PWS, (e) clinician expertise and roles, (f) teacher/counsellor roles and client/public reactions, (g) therapy strategies, and (h) parent attitudes. Descriptive data were presented and Multivariate Analysis of Variance was conducted to examine the effects of clinical certification on the eight domains of attitudes toward stuttering.

    RESULTS: Participants who possessed a clinical certification were more accepting toward the personalities of people who stutter (PWS) and therapy strategies. On the other hand, participants without a clinical certification were more accepting toward clinician expertise and roles.

    CONCLUSIONS: Current curriculum and professional training should be re-evaluated to remediate less accepting stereotypes held by SLPs and students toward PWS and to enhance essential skills such as counselling.

  20. Tan DB, Yong YK, Tan HY, Kamarulzaman A, Tan LH, Lim A, et al.
    HIV Med, 2008 May;9(5):307-16.
    PMID: 18400078 DOI: 10.1111/j.1468-1293.2008.00565.x
    A proportion of HIV patients beginning antiretroviral therapy (ART) develop immune restoration disease (IRD). Immunological characteristics of IRD were investigated in a cohort of HIV patients beginning therapy in Kuala Lumpur, Malaysia.
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