Displaying publications 1 - 20 of 32 in total

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  1. Fulltext A double-blind randomised controlled trial on the effect of Tocovid, a tocotrienol-rich capsule on postoperative atrial fibrillation at the National Heart Institute, Kuala Lumpur: an interim blinded analysis
    Musa AF, Dillon J, Md Taib ME, Yunus AM, Sanusi AR, Nordin MN, et al.
    J Cardiothorac Surg, 2021 Nov 24;16(1):340.
    PMID: 34819126 DOI: 10.1186/s13019-021-01721-6
    INTRODUCTION: Post-operative atrial fibrillation (POAF) is associated with poorer outcomes, increased resource utilisation, morbidity and mortality. Its pathogenesis is initiated by systemic inflammation and oxidative stress. It is hypothesised that a potent antioxidant and anti-inflammatory agent such as tocotrienol, an isomer of Vitamin E, could reduce or prevent POAF.

    AIMS: The aim of this study is to determine whether a potent antioxidative and anti-inflammatory agent, Tocovid, a tocotrienol-rich capsule, could reduce the incidence of POAF and affect the mortality and morbidity as well as the duration of ICU, HDU and hospital stay.

    METHODS: This study was planned as a prospective, randomised, controlled trial with parallel groups. The control group received placebo containing palm superolein while the treatment group received Tocovid capsules. We investigated the incidence of POAF, the length of hospital stay after surgery and the health-related quality of life.

    RESULTS: Recruitment commenced in January 2019 but the preliminary results were unblinded as the study is still ongoing. Two-hundred and two patients have been recruited out of a target sample size of 250 as of January 2021. About 75% have completed the study and 6.4% were either lost during follow-up or withdrew; 4% of participants died. The mean age group was 61.44 ± 7.30 years with no statistical difference between the groups, with males having a preponderance for AF. The incidence of POAF was 24.36% and the mean time for developing POAF was 55.38 ± 29.9 h post-CABG. Obesity was not a predictive factor. No statistically significant difference was observed when comparing left atrial size, NYHA class, ejection fraction and the premorbid history. The mean cross-clamp time was 71 ± 34 min and the mean bypass time was 95 ± 46 min, with no difference between groups. There was a threefold increase in death among patients with POAF (p = 0.008) and an increase in the duration of ICU stay (p = 0.01), the total duration of hospital stay (p = 0.04) and reintubation (p = 0.045).

    CONCLUSION: A relatively low incidence rate of POAF was noted although the study is still ongoing. It remains to be seen if our prophylactic intervention using Tocovid would effectively reduce the incidence of POAF. Clinical Registration Number: US National Library of Medicine. Clinical Trials - NCT03807037. Registered on 16th January 2019. Link: https://clinicaltrials.gov/ct2/show/NCT03807037.

  2. Fulltext A retrospective review on minimally invasive technique via endoscopic thoracic sympathectomy (ETS) in the treatment of severe primary hyperhidrosis: Experiences from the National Heart Institute, Malaysia
    Musa AF, Gandhi VP, Dillon J, Nordin RB
    F1000Res, 2018;7:670.
    PMID: 32724556 DOI: 10.12688/f1000research.14777.1
    Background: Hyperhidrosis is due to the hyperactive autonomic stimulation of the sweat glands in response to stress. Primary hyperhidrosis is a common yet psychologically disabling condition. This study will describe our experience in managing hyperhidrosis via endoscopic thoracic sympathectomy (ETS). Methods: The information was obtained from the patient records from 1 st January 2011 until 31 st December 2016. Pertinent information was extracted and keyed into a study proforma. Results:  150 patients were operated on but only 118 patients were included in this study. The mean age was 22.9±7.3 years. The majority (54.2%) had palmar-plantar hyperhidrosis and 39.8% had associated axillary hyperhidrosis. Excision of the sympathetic nerve chain and ganglia were the main surgical technique with the majority (55.9%) at T2-T3 level. Mean ETS procedure time was 46.6±14.29 minutes with no conversion. Surgical complications were minimal and no Horner's Syndrome reported. Mean hospital stay was 3.5±1.05 days. The majority of patients (67.8%) had only one follow-up and only half of the study sample (58.5%) complained mild to moderate degree of compensatory sweating, even though the long-term resolution is yet to be determined by another study. Following ETS, 98.3% of patients had instant relief and resolved their palmar hyperhidrosis. Predictors of CS were sympathectomy level and follow-up. The odds of reporting CS was 2.87 times in patients undergoing ETS at the T2-T3 level compared to those undergoing ETS at the T2-T4 level. The odds of reporting CS was 13.56 times in patients having more than one follow-up compared to those having only one follow-up. Conclusion: We conclude that ETS is a safe, effective and aesthetically remarkable procedure for the treatment of primary hyperhidrosis  with only half of the patients developing mild to moderate degree of CS. Significant predictors of CS were sympathectomy level during ETS and frequency of follow-up after ETS.
  3. Fulltext A retrospective study on atrial fibrillation after coronary artery bypass grafting surgery at The National Heart Institute, Kuala Lumpur
    Farouk Musa A, Quan CZ, Xin LZ, Soni T, Dillon J, Hay YK, et al.
    F1000Res, 2018;7:164.
    PMID: 30254739 DOI: 10.12688/f1000research.13244.2
    Background: Atrial fibrillation (AF) is common after cardiac surgery and has been associated with poor outcome and increased resource utilization. The main objective of this study is to determine the incidence of POAF in Malaysia and identify the predictors of developing POAF. The secondary outcome of this study would be to investigate the difference in mortality and morbidity rates and the duration of intensive care unit (ICU), high dependency unit (HDU) and hospital stay between the two. Methods: This is a retrospective single-center, cross sectional study conducted at the National Heart Institute, Malaysia. Medical records of 637 who underwent coronary artery bypass grafting (CABG) surgery in 2015 were accrued. Pre-operative, operative and post-operative information were subsequently collected on a pre-formulated data collection sheet. Data were then analyzed using IBM SPSS v23. Results: The incidence of POAF in our study stands at 28.7% with a mean onset of 45±33 hours post operatively. Variables with independent association with POAF include advancing age, Indian population, history of chronic kidney disease, left ventricular ejection fraction and beta-blocker treatment. The mortality rate is significantly higher statistically ( p < 0.05), and similarly the incidence of stroke. The incidence of other post-operative complications was also significantly higher statistically. The duration of ICU, HDU and hospital stays were statistically longer ( p < 0.001) with higher rates of ICU readmissions and reintubations seen. Conclusion: We conclude that the incidence of POAF in Malaysia is comparable to the figures in Western countries, making POAF one of the most commonly encountered condition after CABG with similar higher rates of mortality, poor outcomes and longer duration of stay, and therefore increased cost of care. Strategies to reduce the incidence of AF after cardiac surgery should favorably affect surgical outcomes and reduce utilization of resources and thus lower cost of care.
  4. Acrylamide optical sensor based on hydrolysis using bacillus sp. Strain ZK34 containing amidase properties
    Yee-May Chong, Lee YH, Norzila Kusnin, Mohd Yunus Abdul Shukor, Musa Ahmad
    Sains Malaysiana, 2017;46:1557-1567.
    In this work, a new optical screening method for acrylamide was developed. Bacterial Bacillus sp. strain ZK 34 was used to
    hydrolyse acrylamide to the corresponding acid and ammonia. Nessler’s reagent was used to detect the produced ammonia
    and the yellow complex formed was treated as signal. Bacterial pellet was immobilised in the alginate membrane. The
    optimum composition of alginate used is 2%. The mass ratio of alginate:bacterial of 1:0.5 gave the optimum respond.
    Optimum concentration for NaOH and Nessler’s reagent were 0.075 M and 2.5 mM, respectively. The yellow complex
    of mercury (II) amido-iodine formed was directly proportional to the concentrations of acrylamide up to 50.00 ppm
    with the limit of detection of 1.30 ppm. This sensor shows a good reproducibility which the relatives standard deviation
    (RSD) values from 3.17-6.15%. Therefore, the detection of acrylamide based on the amidase hydrolysis is suitable for
    screening this carcinogen compound.
  5. An optical sensor based on immobilized copper(ii) ions for the determination of free glutamate in food samples
    Noor Zuhartini Md Muslim, Musa Ahmad, Lee YH, Bahruddin Saad
    Sains Malaysiana, 2018;47:707-713.
    An optical fiber chemical sensor for the determination of free glutamate in food samples was fabricated based on the
    immobilization of 0.1 M copper(II) nitrate trihydrate onto sol-gel glass powder which was then mixed with methyl cellulose
    to form a pellet. A distinctive colour change from light blue to dark blue was observed in the presence of glutamate in
    less than 1 min. The colour change was measured by reflectance spectrophotometer at 691 nm. A linear relationship
    between the reflectance intensity and glutamate concentration was observed in the range of 12.5 to 500 mM with a limit
    of detection of 10.6 mM. This method is also reproducible with a relative standard deviation of less than 5%, no effect on
    pH of the glutamate solution and a good recovery of above 80%. The sensor was used for the determination of glutamate
    in common food items such as soups and flavor enhancers. The results obtained from the fabricated sensor were found
    to be comparable with HPLC method.
  6. Analisis kuantitatif aluminium (III) menggunakan reagen alizarin red S dan jaringan neural tiruan (ANN)
    Nurul Izzaty Hassan, Musa Ahmad
    Sains Malaysiana, 2007;36:189-194.
    Analisis kuantitatif untuk penentuan kepekatan ion Al3+ dalam larutan akueus telah dilakukan menggunakan reagen alizarin red S (ARS) melalui pembentukan kompleks ARS-Al(III) yang dianalisis menggunakan kaedah spektrofotometri UL-Nampak. Kompleks ARS-Al(III) memberikan puncak serapan pada panjang gelombang 484 nm pada pH 5. Kajian kestabilan foto bagi reagen ARS memberikan nilai RSD sebanyak 0.46 %. Analisis kebolehulangan memberikan nilai RSD sebanyak 1.07 % dan 0.67 % masing-masingnya bagi kepekatan Al(III) 0.2 ppm dan 9 ppm. Gangguan kation Cu2+ dan Fe3+ pada nisbah mol 1:10 adalah minimum. Kebanyakan anion penggangu tidak memberikan kesan gangguan kecuali F- pada nisbah mol 1:1 dan 1:10. Sistem ini memberikan julat kepekatan dinamik Al3+ antara 0.1 – 1.0 ppm. Arkitektur ANN dengan bilangan neuron terlindung, bilangan kitaran dan kadar pembelajaran adalah masing-masingnya 23, 40000 dan 0.001 telah berjaya memanjangkan julat dinamik kepekatan Al(III) daripada 0.1 – 8.0 ppm. Reagen ARS berjaya dipegunkan pada permukaan ko-polimer XAD 4 dan mampu memberikan respon optik yang baik terhadap ion Al3+.
  7. Bahan sensor untuk pengesanan pH menggunakan ekstrak rosel
    Nurul Huda Abd. Karim, Musa Ahmad, Mohammad Osman, Herman, Ahmad Mahir Mokhtar
    Sains Malaysiana, 2008;37.
    Kajian ini menilai potensi ekstrak pewarna kaliks Hibiscus Sabdariffa L. (rosel) sebagai bahan sensor. Dalam kajian ini, sensor pH dibangunkan menggunakan ekstrak warna kemerahan semulajadi dalam kelopak rosel, delfinidin-3-sambubiosida yang dipegunkan dalam kertas turas gentian kaca. Dalam larutan bebas, ekstrak rosel dicirikan menggunakan spektrofotometer UL-nampak untuk mengkaji kesan pH, kepekatan ekstrak, masa ransangan keadaan mantap, analisis kebolehulangan dan analisis kestabilan foto. Ekstrak rosel terpegun dicirikan dengan menggunakan spektrofotometer pantulan untuk mengkaji kesan pH, masa ransangan keadaan mantap, analisis kebolehulangan, analisis kestabilan foto dan kajian histerisis. Hasil kajian menunjukkan bahawa ekstrak bahan semulajadi boleh digunakan sebagai bahan sensor dalam pembinaan sensor optik pH.
  8. Bahan untuk Pengesanan pH Menggunakan Membran Nafion Terdop dengan Reagen Fenol Merah (Sensing Material for pH Detection Using Nafion Membrane Doped with Phenol Red-Reagent)
    Nur Azlinawati Md. Khlid, Musa Ahmad
    Sains Malaysiana, 2004;33.
    Optical sensing material for detection of pH has been prepared by immobilising phenol red in nafion membrane. Glass slides with dimension 3 in × 1 in were used as a support. The nafion membrane doped with phenol red was characterized by using uv-Visible Spectrophotometer to study the responses at different pH, repeatability and photo stability. The sensing materials were able to be used for the development of an optical pH sensor since the reagent could be successfully immobilised and produced good responses at different pH.
    Bahan sensor untuk pengesanan pH telah disediakan dengan memegunkan reagen fenol merah dalam membran nafion. Slaid kaca yang berukuran 3 in × 1 in telah digunakan sebagai penyokong. Setelah dipegunkan. membran terdop dengan reagen fenol merah dicirikan menggunakan Spektrofotometer uL-Nampak untuk mengkaji kebolehulangan. kestabilan foto dan kesan terhadap pH berbeza. Hasil kajian menunjukkan bahawa bahan ini boleh digunakan sebagai bahan sensor dalam pembinaan sensor optik pH kerana reagen berjaya dipegunkan dan memberikan rangsangan yang baik pada pH yang berbeza.
  9. Bioanalisis berasaskan sistem glutamat dehidrogenase-diaporase untuk pengesanan ammonium
    Nur Ellina Azmi, Jaafar Abdullah, Musa Ahmad, Lee YH, Hamidah Sidek, Samsulida Abd Rahman
    Sains Malaysiana, 2011;40:1263-1269.
    Bioanalisis bagi pengesanan ammonium berdasarkan penggunaan sistem dua enzim Glutamat dehidrogenase-Diaporase (GLDH-Dph) dan reagen tiazolil biru tetrazolium bromida (MTT) diterangkan. Dalam kajian ini, GLDH memangkinkan tindak balas penukaran asid α-ketoglutarik membentuk L-glutamat dan kofaktor β-nikotinamida adenina dinukleotida (NADH) akan dioksidakan kepada NAD+ dengan kehadiran ammonium. Seterusnya, baki NADH yang tidak digunakan dioksidakan kepada NAD+ oleh Dph dan MTT dan diturunkan kepada formazan yang berwarna ungu. Keamatan formazan yang terbentuk dicerap menggunakan spektrofotometer pada panjang gelombang 563 nm. Bioanalisis ini memberikan rangsangan yang optimum bagi pengesanan ammonium pada pH larutan penimbal fosfat bersamaan 8, kepekatan GLDH, Dph dan reagen MTT pada 13.2 unit/mL, 1.17 unit/mL dan 0.2 mM, masing-masing. Bioanalisis ini memberikan rangsangan linear terhadap ammonium dalam julat kepekatan 3 - 50 μM dengan had pengesanan 1 μM.
  10. Fulltext Determination of ammonium ion using a reagentless amperometric biosensor based on immobilized alanine dehydrogenase
    Tan LL, Musa A, Lee YH
    Sensors (Basel), 2011;11(10):9344-60.
    PMID: 22163699 DOI: 10.3390/s111009344
    The use of the enzyme alanine dehydrogenase (AlaDH) for the determination of ammonium ion (NH(4)(+)) usually requires the addition of pyruvate substrate and reduced nicotinamide adenine dinucleotide (NADH) simultaneously to effect the reaction. This addition of reagents is inconvenient when an enzyme biosensor based on AlaDH is used. To resolve the problem, a novel reagentless amperometric biosensor using a stacked methacrylic membrane system coated onto a screen-printed carbon paste electrode (SPE) for NH(4)(+) ion determination is described. A mixture of pyruvate and NADH was immobilized in low molecular weight poly(2-hydroxyethyl methacrylate) (pHEMA) membrane, which was then deposited over a photocured pHEMA membrane (photoHEMA) containing alanine dehydrogenase (AlaDH) enzyme. Due to the enzymatic reaction of AlaDH and the pyruvate substrate, NH(4)(+) was consumed in the process and thus the signal from the electrocatalytic oxidation of NADH at an applied potential of +0.55 V was proportional to the NH(4)(+) ion concentration under optimal conditions. The stacked methacrylate membranes responded rapidly and linearly to changes in NH(4)(+) ion concentrations between 10-100 mM, with a detection limit of 0.18 mM NH(4)(+) ion. The reproducibility of the amperometrical NH(4)(+) biosensor yielded low relative standard deviations between 1.4-4.9%. The stacked membrane biosensor has been successfully applied to the determination of NH(4)(+) ion in spiked river water samples without pretreatment. A good correlation was found between the analytical results for NH(4)(+) obtained from the biosensor and the Nessler spectrophotometric method.
  11. Effects of Gold Nanoparticles on the Response of Phenol Biosensor Containing Photocurable Membrane with Tyrosinase
    Sharina AH, Lee YH, Musa A
    Sensors (Basel), 2008 Oct 16;8(10):6407-6416.
    PMID: 27873876
    The role of incorporation of gold nanoparticles (50-130 nm in diameter) into a series of photocurable methacrylic-acrylic based biosensor membranes containing tyrosinase on the response for phenol detection was investigated. Membranes with different hydrophilicities were prepared from 2-hydroxyethyl methacrylate and n-butyl acrylate via direct photocuring. A range of gold nanoparticles concentrations from 0.01 to 0.5 % (w/w) was incorporated into these membranes during the photocuring process. The addition of gold nanoparticles to the biosensor membrane led to improvement in the response time by a reduction of approximately 5 folds to give response times of 5-10 s. The linear response range of the phenol biosensor was also extended from 24 to 90 mM of phenol. The hydrophilicities of the membrane matrices demonstrated strong influence on the biosensor response and appeared to control the effect of the gold nanoparticles. For less hydrophilic methacrylic-acrylic membranes, the addition of gold nanoparticles led to a poorer sensitivity and detection limit of the biosensor towards phenol. Therefore, for the application of gold nanoparticles in the enhancement of a phenol biosensor response, the nanoparticles should be immobilized in a hydrophilic matrix rather than a hydrophobic material.
  12. Elektrod Ag/AgCl sebagai Transduser Potentiometrik untuk Sensor/Biosensor Jenis Keadaan-Pepejal (Ag/AgCl Electrode for Potentiometric Traansducer for Solid State Sensors (biosensors)
    Khor SM, Lee YH, Musa Ahmad
    Sains Malaysiana, 2004;33.
    A study on the design of solid-state ion sensor was carried out. The electrode used was based on Ag/AgCl and two types of Ag/AgCl electrode designs used were rod-shape and screen printed (SPE) Ag/AgCl electrodes. The assessment of the electrode response was based on anion response, especially the response of chloride ions. Apart from that, the solid-state electrodes were also assessed for their response to several cations after a photocured polymer membrane with an immobilised lipophilic salt sensitive to cations was deposited on the electrodes. The results show that the use of a poly(hydroxyl ethyl methacrylate) hydrated with a salt solution is important to replace the inner reference solution of a conventional non solid-state ion­-selective electrode if normal response of an electrode is to be obtained. The sensor response which remains near to Nernstian after undergoing membrane deposition processes by photocuring technique indicate that these solid-state ion sensors can be used for the construction of biosensors that are based on potentiometric transduction.
    Kajian rekabentuk sensor ion jenis keadaan-pepejal telah dilakukan. Elektrod yang digunakan adalah berdasarkan kepada Ag/AgCl. Rekabentuk dua jenis elektrod keadaan pepejal telah dipilih, iaitu berdasarkan elektrod Ag/AgCl jenis rod dan jenis elektrod Ag/AgCl bercetak skrin (screen printed electrode, SPE). Penilaian termasuk kajian responsnya terhadap anion, khasnya ion klorida. Di samping itu, respons elektrod keadaan-pepejal ini terhadap beberapa kation juga dilakukan setelah elektrod rod dan SPE disalutkan dengan beberapa jenis fotopolimer serta pemegunan garam lipofilik yang peka kepada kation. Hasil kajian menunjukkan penggunaan poli(hidroksi etil metakrilat) terhidrat dengan larutan garam untuk menggantikan larutan rujukan dalaman bagi elektrod pemilih ion konvensional yang bukan berbentuk keadaan-pepejal adalah penting demi menghasilkan sensor berbentuk keadaan pepejal yang bersifat normal. Ciri sensor ion yang masih bersifat hampir Nernstian walaupun telah mengalami beberapa proses fabrikasi sistem fotopolimer menunjukkan bahawa sensor keadaan-pepejal ini boleh juga digunakan dalam rekabentuk biosensor potentiometrik selain daripada sensor ion.
  13. Equation modeling of Sembulan river, Sabah, as a case study using backward stepwise multiple linear regression
    Rita Sundari, Musa Ahmad, Lee YH
    Sains Malaysiana, 2006;35:67-73.
    An equation modeling on Sembulan river, Sabah, Malaysia, has been undertaken using a backward stepwise multiple linear regression. A good performance has been obtained using a log transformation on water quality data designated as predictors and dependent variable. The regression model is in accordance with the ANOVA result. The temperature, biochemical oxygen demand (BOD), Echerichia Coli, Pb and nitrate were described as continuous predictors, while the river location (downstream, municipal and upstream) was designated as independent string grouping variable, and the chemical oxygen demand (COD) was set up as the dependent variable. The string grouping variable was converted to its dummy variable, which in turn led to design of a three-equation model with respect to river location. The results show that BOD has a strong effect on COD, while Pb and nitrate show less effect on COD. The temperature gives little negative effect on COD, while other variables such as pH, salinity and Cd are excluded from the river modeling since they induce insignificant effects based on backward criterion probability of F-value ≥ 0.100. Using the general linear model with LSD mode, it is revealed that predictor(s) show a remarkable discriminant effect between upstream and municipal/downstream on the 0.05 level. The most effect came from salinity indicated by the canonical discriminant function based on Wilks’ lambda.
  14. Extending the range of an optical vanadium(v) sensor based on immobilized fatty hydroxamic acid in poly (methyl methacrylate) using artificial neural network
    Azizul Isha, Nor Azah Yusof, Musa Ahmad, Dedy Suhendra, Wan Md. Zin Wan Yunus, Zulkarnain Zainal
    Pertanika Journal of Science & Technology, 2007;15(2):121-130.
    MyJurnal
    An artificial neural network (ANN) was applied for the determination of V(V) based on immobilized fatty hydroxamic acid (FHA) in poly(methyl methacrylate) (PMMA). Spectra obtained from the V(V)-FHA complex at single wavelengths was used as the input data for the ANN. The V(V)-FHA complex shows a limited linear dynamic range of V(V) concentration of 10 - 100 mg/ L. After training with ANN, the linear dynamic range was extended with low calibration error. A three layer feed forward neural network using backpropagation (BP) algorithm was employed in this study. The input layer consisted of single neurons, 30 neurons in hidden a layer and one output neuron was found appropriate for the multivariate calibration used. The network were trained up to 10000 epochs with 0.003 % learning rate. This reagent also provided a good analytical pedormance with reproducibility characters of the method yielding relative standard deviation (RSD) of 9.29% and 7.09% for V(V) at concentrations of 50 mg/ L and 200 mg/ L, respectively. The limit of detection of the method was 8.4 mg/ L.
  15. Factor Structure of the Spiritual Well-Being Scale: Cross-Cultural Comparisons Between Jordanian Arab and Malaysian Muslim University Students in Jordan
    Musa AS
    J Transcult Nurs, 2016 Mar;27(2):117-25.
    PMID: 24867886 DOI: 10.1177/1043659614537305
    This study reported the differences in factor structure of the Spiritual Well-Being Scale (SWBS) among Jordanian Arab and Malaysian Muslim participants and further examined its validity and reliability. A convenience sample of 553 Jordanian Arab and 183 Malaysian Malay Muslim university students was recruited from governmental universities in northern Jordan. The findings of this study revealed that this scale consists of two factors for the Jordanian Arab group, representing the "Religious Well-Being" and the "Existential Well-Being" subscales, and consists of three factors for the Malaysian group, representing the "Affiliation/Meaning and Purpose," "Positive Existential Well-Being/God Caring and Love," and "Alienation/Despair" subscales. In conclusion, the factor structure of the SWBS for both groups in this study was psychometrically sound with evidence of acceptable to good validity and reliability. Furthermore, this study supported the multidimensional nature of the SWBS and the earlier notion that ethnicity shapes responses to this scale.
  16. Fulltext Intracranial metastatic neuroblastoma mimicking subdural empyema: an interesting case
    Hairuddin NF, Musa AT, Abdullah MS
    Malaysian Journal of Paediatrics and Child Health, 2016;22(1):66-70.
    MyJurnal
    Neuroblastoma is usually presented with abdominal distension. However, central nervous system manifestations of neuroblastoma are uncommon. In this case report, patient presented with uncommon presentation of neuroblastoma and the diagnostic dilemma.
  17. Kesan penambahan surfaktan tak-ionik kepada kompleks Al(III)-morin dalam penentuan aluminium (III) akues secara spektrofotometri
    Faiz Bukhari Mohd Suah, Musa Ahmad, Lee YH
    Sains Malaysiana, 2016;45:1807-1814.
    Dalam kajian ini, kesan surfaktan tak-ionik terhadap kompleks Al(III)-morin telah dijalankan. Surfaktan tak-ionik didapati telah meningkatkan bacaan serapan kompleks Al(III)-morin. Penambahan triton X-100 kepada kompleks Al(III)-morin telah membolehkan penentuan ion Al(III) dalam kuantiti submikrogram pada pH4.00 dijalankan. Bacaan serapan maksimum adalah pada 425 nm dengan serapan molar, ε, 9.31 × 103 l.mol-1cm-1. Graf kalibrasi bagi penentuan ion Al(III) adalah linear daripada 0.03 hingga 2.0 μg mL-1 dengan had pengesanan 0.015 μg mL-1 telah diperoleh dalam kajian ini. Sisihan ralat relatif (r.s.d) ialah 2.2% bagi kepekatan Al(III) 1.0 μg mL-1. Kesan penambahan ion lain terhadap kompleks Al(III)-morin turut dijalankan dan didapati ion Cu(II), Zn(II) dan Pb(II) memberi gangguan yang lebih berbanding ion-ion lain.
  18. Molecularly imprinted polymer for recognition of p-Xylene in organic medium
    Norlaili Abu Bakar, Musa Ahmad, Rusli Daik
    Sains Malaysiana, 2008;37:233-237.
    Molecularly imprinted polymer (MIP) based on acrylate monomer was prepared at 80°C for 5 hours using p-xylene and ethylene glycol dimethacrylate (EGDMA) as a template and crosslinking agent respectively. The polymer obtained was washed with a mixture of acetic acid and methanol (1:4) and dried in the vacuum oven at 80°C. FTIR spectrum showed that all the templates were leached out from polymer during excessive washing and drying stage. The rebinding test result showed that the MIP was bonded with the analyte in the presence of organic solvents as shown by FTIR spectroscopy. The SEM micrograph showed that non-imprinted polymer (NIP) had no cavity as compared to MIP.
  19. Pembangunan sensor optik pH berasaskan reagen kurkumin terpegun dalam matriks hibrid sol-gel/kitosan melamin
    Rosmawani Mohammad, Musa Ahmad, Jamaluddin Mohd Daud
    Sains Malaysiana, 2009;38.
    Sensor optik pH berasaskan reagen kurkumin terpegun dalam matriks hibrid sol-gel/kitosan melamin telah dibangunkan dalam kajian ini. Sensor optik pH ini memberikan rangsangan linear pada julat pH 9-13 (R2 = 0.9846). Seterusnya, nilai RSD kebolehulangan adalah 7.38% - 9.65%, manakala nilai RSD kebolehasilan pula adalah 2.18% - 4.72%. Kestabilanfoto yang baik bagi reagen kurkumin terpegun diperolehi apabila filem disimpan dalam persekitaran gelap dengan nilai RSD 3.69% untuk tempoh kajian 3 minggu. Tiada kesan histerisis diperhatikan apabila sensor digunakan untuk mengukur pH dalam kitaran pH 2-12-2. Masa rangsangan sensor adalah 10-20 saat. Penentuan nilai pH bagi beberapa sampel sebenar menggunakan sensor pH yang dihasilkan dalam kajian ini menunjukkan tiada perbezaan secara signifikan pada nilai pH yang diperolehi apabila dibandingkan dengan keputusan yang diperolehi menggunakan meter pH.
  20. Penggunaan Jaringan Neural Tiruan bagi menentukan Kekeruhan air berdasarkan Pencaman Corak Spektrum Pantulan (The use of Artificial Neural Network for Determination of Water Turbidity based on Pattern Recognition of the Reflectance Spectrum)
    Mohd. Azwani Shah Mat Lazim, Musa Ahmad, Zuriati Zakaria, Mohd. Nasir Taib
    Sains Malaysiana, 2005;34.
    Artificial neural network (ANN) was used in this study to determine water turbidity by using back propagation algorithm. Three wavelengths which represent reflectance intensity for eight standard samples were used as training input. The finding from the study shows that the trained network with number of epochs of 250,000 and learning rate of 0.001 gave the lowest sum of squared error (SSE) of 0.04. ANN was able to predict the turbidity of water based on the pattern recognition of the reflectance spectrum. The architecture of optimized ANN used in this study was 3:25:1. The average prediction error was 0.02.
    [Jaringan neural tiruan (ANN) dengan lagoritma perambatan balik (BP) telah digunakan dalam kajian ini untuk menentukan kekeruhan air. Tiga panjang gelombang yang mewakili serapan bagi lapan sampel telah dipilih sebagai imput latihan. Hasil kajian menunjukkan bagi jaringan terlatih dengan bilangan ulangan latihan 250,000 dan kadar pembelajaran 0.001 telah memberikan nilai SSE yang terendah iaitu 0.04. Dalam kajian ini jaringan ANN didapati boleh menentu dan meramalkan nilai kekeruhan sample air berdasarkan corak serapan pantulan. Arkitektur yang sesuai bagi kajian ini adalah 3:25:1. Purata ralat ramalan adalah 0.02].
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