Displaying all 15 publications

  1. Ujang Z, Ng SS, Nagaoka H
    Water Sci Technol, 2005;51(10):335-42.
    PMID: 16104438
    Biofouling control is important for effective process of membrane bioreactor (MBR). In this study, phenomena of biofouling for immersed type extended aeration MBR with two different anti-fouling aeration intensities were studied through a laboratory set up. The objectives of this study were (a) to observe biofouling phenomena of MBR that operates under different anti-fouling bubbling intensity, and simultaneously monitors performance of the MBR in organic carbon and nutrients removal; (b) to compare effectiveness of detergent and detergent-enzyme cleaning solutions in recovering biofouled membranes that operated in the extended aeration MBR. For MBR, which operated under continuous anti-fouling aeration, deposition and accumulation of suspended biomass on membrane surface were prohibited. However, flux loss was inescapable that biofilm layer was the main problem. Membrane cleaning was successfully carried out with detergent-enzyme mixture solutions and its effectiveness was compared with result from cleaning with just detergent solution.
  2. Ng SS, Kwan MK, Ahmad TS
    Med J Malaysia, 2006 Dec;61 Suppl B:13-7.
    PMID: 17600987
    This study is designed to evaluate twenty patients after sural nerve harvest using the single longitudinal incision method. The area of sensory loss to pin prick was assessed by the authors at different intervals. Donor site factors, scar cosmesis, functional status and complications were assessed using a questionnaire. The mean area of anaesthesia at one month was 65 cm2 and it had reduced by 77% to 15 cm2 at one and a half years. The mean area of reduced sensation was 49 cm2 at one month and it increased by 18% to 58 cm2 over the same period. Therefore, the total area of sensory deficit was reduced by 36% from 114 cm2 at one month to 73 cm2 at one and a half years. Subjective patient evaluation indicated moderate level of pain during immediate post surgical period, which reduced significantly at one month. A low level of neuroma symptoms was recorded throughout the study period. At a mean follow-up period of two years, there was no area of anaesthesia in 50% of the patients. Mean area of anaesthesia for all patients was 12 cm2 and mean area of reduced sensation was 55 cm2. Subjective patient evaluation indicated a low level of pain, neuroma symptoms and numbness over the sural nerve sensory distribution. Twenty five percent of the patients were not satisfied with the scar appearance. Function and daily activities were not affected significantly. No surgical complications were observed.
  3. Ng SS, Hutubessy R, Chaiyakunapruk N
    Vaccine, 2018 05 03;36(19):2529-2544.
    PMID: 29625764 DOI: 10.1016/j.vaccine.2018.03.024
    BACKGROUND: The success of human papillomavirus (HPV) national immunization program depends on effective strategies in optimizing the uptake of HPV vaccine. Given the increasing number of economic evaluations, this review was conducted to update the economic evidence on HPV vaccination, by focusing on: (i) 9-valent vaccine compared to bi- or quadrivalent vaccine; (ii) gender-neutral vaccination compared to female only vaccination; and (iii) multiple age cohort immunization compared to single age cohort immunization.

    METHODS: Searches were performed until June 2016 using 4 databases: PubMed; Embase; Cochrane Library; and LILACS. The combined WHO, Drummond and CHEERS checklist were used to evaluate the quality of included studies.

    RESULTS: Thirty-four studies were included in the review and most of them were conducted in high-income countries. The inclusion of adolescent boys in vaccination program was found to be cost-effective if vaccine price and coverage was low. When coverage for female was above 75%, gender-neutral vaccination was less cost-effective than when targeting only girls aged 9-18 years. Current evidence does not show conclusive proof of greater cost-effectiveness of 9-valent vaccine compared to the older HPV vaccines as the price for 9-valent vaccine was still uncertain. Multicohort immunization strategy was cost-effective in the age range 9-14 years but the upper age limit at which vaccination was no longer cost-effective needs to be further investigated. Key influential parameters identified were duration of vaccine protection, vaccine price, coverage, and discounting rates.

    CONCLUSIONS: These findings are expected to support policy-makers in making recommendations for HPV immunization programs on either switching to the 9-valent vaccine or inclusion of adolescent boys' vaccination or extending the age of vaccination.

  4. Ng SS, Naing L, Idris FI, Pande K
    Malays Orthop J, 2020 Jul;14(2):39-46.
    PMID: 32983376 DOI: 10.5704/MOJ.2007.009
    Introduction: Lower limb amputations have a profound impact on the quality of life (QoL) of the patients. This study was done to assess the QoL of patients with transtibial (below-the-knee) amputations (TTA) and transtibial amputees fitted with prosthesis.

    Material and Methods: A case-control study of patients who had undergone TTA from 2015 to 2018 was conducted in Raja Isteri Pengiran Anak Saleha Hospital (RIPAS). Complete data was available for 30 subjects and it was compared with 30 diabetic, non-amputee patients matched for age and gender. QoL was assessed using the RAND 36-Item Health Survey (SF-36) and the functional outcome of prosthesis-fitted transtibial amputees was assessed using the Houghton Scale.

    Results: Almost all cases of TTA were a result of vascular problems related to diabetes and chronic renal disease (n=29; 97%). Eighteen (60%) participants were fitted with prosthesis and 15 (50%) reported having phantom pain. QoL of participants was found to be significantly lower than that of age and sex-matched diabetic non-amputees with regards to physical functioning, role limitation due to physical health, emotional well-being, social functioning, and bodily pain. The mean Houghton Score for participants fitted with prosthesis was 4.89 (SD= 2.83) suggesting low functional outcome.

    Conclusion: TTA has a negative impact on the QoL of patients, especially in terms of functionality. The availability of prosthesis does not significantly improve the quality of life except in the physical functioning domain. Emotional well-being should be emphasised more in the rehabilitation process as this study found poor emotional well-being among participants.

  5. Ng SS, Lai NM, Nathisuwan S, Chaiyakunapruk N
    Clin Drug Investig, 2018 Jul;38(7):579-591.
    PMID: 29569095 DOI: 10.1007/s40261-018-0641-5
    INTRODUCTION: Anticoagulation therapy is the fundamental approach for stroke prevention in atrial fibrillation (AF) patients. Numerous systematic reviews comparing anticoagulation strategies have been published. We aim to summarize the efficacy and safety evidence of these strategies in AF patients from previously published systematic reviews.

    METHODS: We searched PubMed, EMBASE and Cochrane library from inception to Feb 24th, 2017, to identify systematic reviews and meta-analyses of randomized controlled trials that assessed interventions or strategies to improve oral anticoagulant use in AF patients.

    RESULTS: Thirty-four systematic reviews were eligible for inclusion but only 11 were included in the qualitative analyses, corresponding to 40 unique meta-analyses, as the remaining systematic reviews had overlapping primary studies. There was insufficient evidence to support the efficacy of genotype-guided dosing and pharmacist-managed anticoagulation clinics for stroke prevention in AF patients. Conversely, patient's self-management and novel oral anticoagulants (NOACs), in general were superior to warfarin for preventing stroke and reducing mortality. All interventions showed comparable risk of major bleeding with warfarin.

    CONCLUSION: Findings from this overview support the superiority of NOACs and patient's self-management for preventing stroke in AF patients. However, uncertainties remain on the benefits of genotype-guided dosing and pharmacist-managed anticoagulation clinics due to poor quality evidence, and future research is warranted.

  6. Ng SS, Nathisuwan S, Phrommintikul A, Chaiyakunapruk N
    Thromb Res, 2020 01;185:63-71.
    PMID: 31770689 DOI: 10.1016/j.thromres.2019.11.012
    INTRODUCTION: Novel oral anticoagulants (NOACs) and warfarin care bundles (e.g. genotyping, patient self-testing or self-management) are alternatives to usual warfarin care for stroke prevention in patients with atrial fibrillation (AF). We aim to evaluate the cost-effectiveness of NOACs and warfarin care bundles in patients with AF in a middle-income country, Thailand.

    MATERIALS AND METHODS: A Markov model was used to evaluate the economic and treatment outcomes of warfarin care bundles and NOACs compared with usual warfarin care. Cost-effectiveness was assessed from a societal perspective over a lifetime horizon with 3% discount rate in a hypothetical cohort of 65-year-old atrial fibrillation patients. Input parameters were derived from published literature, meta-analysis and local data when available. The outcome measure was incremental cost per quality-adjusted life years (QALY) gained (ICER).

    RESULTS: Using USD5104 as the threshold of willingness-to-pay per QALY, patient's self-management of warfarin was cost-effective when compared to usual warfarin care, with an ICER of USD1395/QALY from societal perspective. All NOACs were not cost-effective in Thailand, with ICER ranging from USD8678 to USD14,247/QALY. When compared to the next most effective intervention, patient's self-testing and genotype-guided warfarin dosing were dominated. In the cost-effectiveness acceptability curve, patient's self-management had the highest probability of being cost-effective in Thailand, approximately 78%. Results were robust over a range of inputs in sensitivity analyses.

    CONCLUSIONS: In Thailand, NOACs were unlikely to be cost-effective at current prices. Conversely, patient's self-management is a highly cost-effective intervention and may be considered for adoption in developing regions with resource-limited healthcare systems.

  7. Saw KG, Tneh SS, Yam FK, Ng SS, Hassan Z
    PLoS One, 2014;9(2):e89348.
    PMID: 24586707 DOI: 10.1371/journal.pone.0089348
    The concentration of acceptor carriers, depletion width, magnitude of donor level movement as well as the sensitivity factor are determined from the UV response of a heterojunction consisting of ZnO on type IIb diamond. From the comparison of the I-V measurements in dark condition and under UV illumination we show that the acceptor concentration (∼10(17) cm(-3)) can be estimated from p-n junction properties. The depletion width of the heterojunction is calculated and is shown to extend farther into the ZnO region in dark condition. Under UV illumination, the depletion width shrinks but penetrates both materials equally. The ultraviolet illumination causes the donor level to move closer to the conduction band by about 50 meV suggesting that band bending is reduced to allow more electrons to flow from the intrinsically n-type ZnO. The sensitivity factor of the device calculated from the change of threshold voltages, the ratio of dark and photocurrents and identity factor is consistent with experimental data.
  8. Saw KG, Tneh SS, Tan GL, Yam FK, Ng SS, Hassan Z
    PLoS One, 2014;9(1):e86544.
    PMID: 24466144 DOI: 10.1371/journal.pone.0086544
    The current-voltage characteristics of Ni contacts with the surfaces of ZnO thin films as well as single crystal (0001) ZnO substrate are investigated. The ZnO thin film shows a conversion from Ohmic to rectifying behavior when annealed at 800°C. Similar findings are also found on the Zn-polar surface of (0001) ZnO. The O-polar surface, however, only shows Ohmic behavior before and after annealing. The rectifying behavior observed on the Zn-polar and ZnO thin film surfaces is associated with the formation of nickel zinc oxide (Ni1-xZnxO, where x = 0.1, 0.2). The current-voltage characteristics suggest that a p-n junction is formed by Ni1-xZnxO (which is believed to be p-type) and ZnO (which is intrinsically n-type). The rectifying behavior for the ZnO thin film as a result of annealing suggests that its surface is Zn-terminated. Current-voltage measurements could possibly be used to determine the surface polarity of ZnO thin films.
  9. Saw KG, Aznan NM, Yam FK, Ng SS, Pung SY
    PLoS One, 2015;10(10):e0141180.
    PMID: 26517364 DOI: 10.1371/journal.pone.0141180
    The Burstein-Moss shift and band gap narrowing of sputtered indium-doped zinc oxide (IZO) thin films are investigated as a function of carrier concentrations. The optical band gap shifts below the carrier concentration of 5.61 × 1019 cm-3 are well-described by the Burstein-Moss model. For carrier concentrations higher than 8.71 × 1019 cm-3 the shift decreases, indicating that band gap narrowing mechanisms are increasingly significant and are competing with the Burstein-Moss effect. The incorporation of In causes the resistivity to decrease three orders of magnitude. As the mean-free path of carriers is less than the crystallite size, the resistivity is probably affected by ionized impurities as well as defect scattering mechanisms, but not grain boundary scattering. The c lattice constant as well as film stress is observed to increase in stages with increasing carrier concentration. The asymmetric XPS Zn 2p3/2 peak in the film with the highest carrier concentration of 7.02 × 1020 cm-3 suggests the presence of stacking defects in the ZnO lattice. The Raman peak at 274 cm-1 is attributed to lattice defects introduced by In dopants.
  10. Lai NM, Chang SMW, Ng SS, Tan SL, Chaiyakunapruk N, Stanaway F
    Cochrane Database Syst Rev, 2019 11 25;2019(11).
    PMID: 31763689 DOI: 10.1002/14651858.CD013243.pub2
    BACKGROUND: Dementia is a chronic condition which progressively affects memory and other cognitive functions, social behaviour, and ability to carry out daily activities. To date, no treatment is clearly effective in preventing progression of the disease, and most treatments are symptomatic, often aiming to improve people's psychological symptoms or behaviours which are challenging for carers. A range of new therapeutic strategies has been evaluated in research, and the use of trained animals in therapy sessions, termed animal-assisted therapy (AAT), is receiving increasing attention.

    OBJECTIVES: To evaluate the efficacy and safety of animal-assisted therapy for people with dementia.

    SEARCH METHODS: We searched ALOIS: the Cochrane Dementia and Cognitive Improvement Group's Specialised Register on 5 September 2019. ALOIS contains records of clinical trials identified from monthly searches of major healthcare databases, trial registries, and grey literature sources. We also searched MEDLINE (OvidSP), Embase (OvidSP), PsycINFO (OvidSP), CINAHL (EBSCOhost), ISI Web of Science, ClinicalTrials.gov, and the WHO's trial registry portal.

    SELECTION CRITERIA: We included randomised controlled trials (RCTs), cluster-randomised trials, and randomised cross-over trials that compared AAT versus no AAT, AAT using live animals versus alternatives such as robots or toys, or AAT versus any other active intervention.

    DATA COLLECTION AND ANALYSIS: We extracted data using the standard methods of Cochrane Dementia. Two review authors independently assessed the eligibility and risk of bias of the retrieved records. We expressed our results using mean difference (MD), standardised mean difference (SMD), and risk ratio (RR) with their 95% confidence intervals (CIs) where appropriate.

    MAIN RESULTS: We included nine RCTs from 10 reports. All nine studies were conducted in Europe and the US. Six studies were parallel-group, individually randomised RCTs; one was a randomised cross-over trial; and two were cluster-RCTs that were possibly related where randomisation took place at the level of the day care and nursing home. We identified two ongoing trials from trial registries. There were three comparisons: AAT versus no AAT (standard care or various non-animal-related activities), AAT using live animals versus robotic animals, and AAT using live animals versus the use of a soft animal toy. The studies evaluated 305 participants with dementia. One study used horses and the remainder used dogs as the therapy animal. The duration of the intervention ranged from six weeks to six months, and the therapy sessions lasted between 10 and 90 minutes each, with a frequency ranging from one session every two weeks to two sessions per week. There was a wide variety of instruments used to measure the outcomes. All studies were at high risk of performance bias and unclear risk of selection bias. Our certainty about the results for all major outcomes was very low to moderate. Comparing AAT versus no AAT, participants who received AAT may be slightly less depressed after the intervention (MD -2.87, 95% CI -5.24 to -0.50; 2 studies, 83 participants; low-certainty evidence), but they did not appear to have improved quality of life (MD 0.45, 95% CI -1.28 to 2.18; 3 studies, 164 participants; moderate-certainty evidence). There were no clear differences in all other major outcomes, including social functioning (MD -0.40, 95% CI -3.41 to 2.61; 1 study, 58 participants; low-certainty evidence), problematic behaviour (SMD -0.34, 95% CI -0.98 to 0.30; 3 studies, 142 participants; very-low-certainty evidence), agitation (SMD -0.39, 95% CI -0.89 to 0.10; 3 studies, 143 participants; very-low-certainty evidence), activities of daily living (MD 4.65, 95% CI -16.05 to 25.35; 1 study, 37 participants; low-certainty evidence), and self-care ability (MD 2.20, 95% CI -1.23 to 5.63; 1 study, 58 participants; low-certainty evidence). There were no data on adverse events. Comparing AAT using live animals versus robotic animals, one study (68 participants) found mixed effects on social function, with longer duration of physical contact but shorter duration of talking in participants who received AAT using live animals versus robotic animals (median: 93 seconds with live versus 28 seconds with robotic for physical contact; 164 seconds with live versus 206 seconds with robotic for talk directed at a person; 263 seconds with live versus 307 seconds with robotic for talk in total). Another study showed no clear differences between groups in behaviour measured using the Neuropsychiatric Inventory (MD -6.96, 95% CI -14.58 to 0.66; 78 participants; low-certainty evidence) or quality of life (MD -2.42, 95% CI -5.71 to 0.87; 78 participants; low-certainty evidence). There were no data on the other outcomes. Comparing AAT using live animals versus a soft toy cat, one study (64 participants) evaluated only social functioning, in the form of duration of contact and talking. The data were expressed as median and interquartile ranges. Duration of contact was slightly longer in participants in the AAT group and duration of talking slightly longer in those exposed to the toy cat. This was low-certainty evidence.

    AUTHORS' CONCLUSIONS: We found low-certainty evidence that AAT may slightly reduce depressive symptoms in people with dementia. We found no clear evidence that AAT affects other outcomes in this population, with our certainty in the evidence ranging from very-low to moderate depending on the outcome. We found no evidence on safety or effects on the animals. Therefore, clear conclusions cannot yet be drawn about the overall benefits and risks of AAT in people with dementia. Further well-conducted RCTs are needed to improve the certainty of the evidence. In view of the difficulty in achieving blinding of participants and personnel in such trials, future RCTs should work on blinding outcome assessors, document allocation methods clearly, and include major patient-important outcomes such as affect, emotional and social functioning, quality of life, adverse events, and outcomes for animals.

  11. Ng SS, Lai NM, Nathisuwan S, Jahan NK, Dilokthornsakul P, Kongpakwattana K, et al.
    Sci Rep, 2020 01 20;10(1):662.
    PMID: 31959803 DOI: 10.1038/s41598-019-57370-2
    Warfarin care bundles (e.g. genotype-guided warfarin dosing, patient's self-testing [PST] or patient's self-management [PSM] and left atrial appendage closure) are based on the concept of combining several interventions to improve anticoagulation care. NOACs are also introduced for stroke prevention in atrial fibrillation (SPAF). However, these interventions have not been compared in head-to-head trials yet. We did a network meta-analysis based on a systematic review of randomized controlled trials comparing anticoagulant interventions for SPAF. Studies comparing these interventions in adults, whether administered alone or as care bundles were included in the analyses. The primary efficacy outcome was stroke and the primary safety outcome was major bleeding. Thirty-seven studies, involving 100,142 patients were assessed. Compared to usual care, PSM significantly reduced the risk of stroke (risk ratio [RR] 0.24, 95% CI 0.08-0.68). For major bleeding, edoxaban 60 mg (0.80, 0.71-0.90), edoxaban 30 mg (0.48, 0.42-0.56), and dabigatran 110 mg (0.81, 0.71-0.94) significantly reduced the risk of major bleeding compared with usual warfarin care. Cluster rank plot incorporating stroke and major bleeding outcomes indicates that some warfarin care bundles perform as well as NOACs. Both interventions are therefore viable options to be considered for SPAF. Additional studies including head-to-head trials and cost-effectiveness evaluation are still warranted.
  12. Ng SS, Lee SC, Bakhori SK, Hassan Z, Abu Hassan H, Yakovlev VA, et al.
    Opt Express, 2010 May 10;18(10):10354-9.
    PMID: 20588890 DOI: 10.1364/OE.18.010354
    Surface phonon polariton (SPP) characteristics of In(0.04)Al(0.06)Ga(0.90)N/AlN/Al(2)O(3) heterostructure are investigated by means of p-polarized infrared (IR) attenuated total reflection spectroscopy. Two absorption dips corresponding to In(0.04)Al(0.06)Ga(0.90)N SPP modes are observed. In addition, two prominent dips and one relatively weak and broad dip corresponding to the Al(2)O(3) SPP mode, In(0.04)Al(0.06)Ga(0.90)N/Al(2)O(3) interface mode, and Al(2)O(3) bulk polariton mode, respectively, are clearly seen. No surface mode feature originating from the AlN layer is observed because it is too thin. Overall, the observations are in good agreement with the theoretical predictions.
  13. Chong KK, Wong CW, Siaw FL, Yew TK, Ng SS, Liang MS, et al.
    Sensors (Basel), 2009;9(10):7849-65.
    PMID: 22408483 DOI: 10.3390/s91007849
    A novel on-axis general sun-tracking formula has been integrated in the algorithm of an open-loop sun-tracking system in order to track the sun accurately and cost effectively. Sun-tracking errors due to installation defects of the 25 m(2) prototype solar concentrator have been analyzed from recorded solar images with the use of a CCD camera. With the recorded data, misaligned angles from ideal azimuth-elevation axes have been determined and corrected by a straightforward changing of the parameters' values in the general formula of the tracking algorithm to improve the tracking accuracy to 2.99 mrad, which falls below the encoder resolution limit of 4.13 mrad.
  14. Lee SC, Ng SS, Oldenburg J, Chong PY, Rost S, Guo JY, et al.
    Clin. Pharmacol. Ther., 2006 Mar;79(3):197-205.
    PMID: 16513444
    Chinese and Malay subjects have been reported to require less maintenance warfarin than Indians that could not be accounted for by cytochrome P450 (CYP) 2C9 variants. Vitamin K epoxide reductase complex 1 (VKORC1) is the target enzyme of warfarin, and VKORC1 intronic variants and haplotypes have recently been shown to influence VKORC1 activity and warfarin requirements.
  15. Sung JJ, Ng SC, Chan FK, Chiu HM, Kim HS, Matsuda T, et al.
    Gut, 2015 Jan;64(1):121-32.
    PMID: 24647008 DOI: 10.1136/gutjnl-2013-306503
    OBJECTIVE: Since the publication of the first Asia Pacific Consensus on Colorectal Cancer (CRC) in 2008, there are substantial advancements in the science and experience of implementing CRC screening. The Asia Pacific Working Group aimed to provide an updated set of consensus recommendations.
    DESIGN: Members from 14 Asian regions gathered to seek consensus using other national and international guidelines, and recent relevant literature published from 2008 to 2013. A modified Delphi process was adopted to develop the statements.
    RESULTS: Age range for CRC screening is defined as 50-75 years. Advancing age, male, family history of CRC, smoking and obesity are confirmed risk factors for CRC and advanced neoplasia. A risk-stratified scoring system is recommended for selecting high-risk patients for colonoscopy. Quantitative faecal immunochemical test (FIT) instead of guaiac-based faecal occult blood test (gFOBT) is preferred for average-risk subjects. Ancillary methods in colonoscopy, with the exception of chromoendoscopy, have not proven to be superior to high-definition white light endoscopy in identifying adenoma. Quality of colonoscopy should be upheld and quality assurance programme should be in place to audit every aspects of CRC screening. Serrated adenoma is recognised as a risk for interval cancer. There is no consensus on the recruitment of trained endoscopy nurses for CRC screening.
    CONCLUSIONS: Based on recent data on CRC screening, an updated list of recommendations on CRC screening is prepared. These consensus statements will further enhance the implementation of CRC screening in the Asia Pacific region.
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