Displaying publications 1 - 20 of 43 in total

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  1. Enhancement of biodegradation of crude petroleum-oil in contaminated water by the addition of nitrogen sources
    Mukred AM, Hamid AA, Hamzah A, Yusoff WM
    Pak J Biol Sci, 2008 Sep 01;11(17):2122-7.
    PMID: 19266926
    Addition of nitrogen sources as supplementary nutrient into MSM medium to enhance biodegradation by stimulating the growth four isolates, Acinetobacter faecalis, Staphylococcus sp., Pseudomonas putida and Neisseria elongata isolated from petroleum contaminated groundwater, wastewater aeration pond and biopond at the oil refinery Terengganu Malaysia was investigated. The organic nitrogen sources tested not only supported growth but also enhances biodegradation of 1% Tapis crude oil. All four isolates showed good growth especially when peptone was employed as the organic nitrogen compared to growth in the basal medium. Gas chromatography showed that more then 91, 93, 94 and 95% degradation of total hydrocarbon was observed after 5 days of incubation by isolates Pseudomonas putida, Neisseria elongate, Acinetobacter faecalis and Staphylococcus sp., respectively.
  2. Growth enhancement of effective microorganisms for bioremediation of crude oil contaminated waters
    Mukred AM, Abd-Hamid A, Hamzah A, Yusoff WM
    Pak J Biol Sci, 2008 Jul 01;11(13):1708-12.
    PMID: 18819623
    The bioremediation of polluted groundwater, wastewater aeration pond and biopond sites was investigated using bacteria isolated from these sites located at the oil refinery Terengganu Malaysia. Out of 62 isolates, only 16 isolates from groundwater (8) and wastewater aeration pond (3) and biopond (5) were chosen based on growth medium containing 1% (v/v) Tapis crude oil. Only four isolates; Acinetobacter faecalis, Staphylococcus sp., Pseudomonas putida and Neisseria elongata showed percentage biodegradation of crude oil more than 50% after 5 days using Mineral Salts Medium (MSM). The effect of physical parameters (temperature, pH and agitation) on growth by all four strains showed a maximum growth in MSM medium with 1% Tapis crude oil at 37 degrees C with pH 7 and agitation of 130 rpm.
  3. Elemental analysis of herbal preparations for traditional medicines by neutron activation analysis with the k0 standardization method
    Sarmani SB, Abugassa I, Hamzah A, Yahya MD
    Biol Trace Elem Res, 1999;71-72:365-76.
    PMID: 10676512
    Medicinal herb preparations prescribed for specific treatment purposes were purchased from markets and were analyzed by instrumental neutron activation analysis with k0 standardization. Then, 500-700 mg of each sample was pelletized under a pressure of six tones and irradiated together with monitors for alpha and neutron flux ratio determinations for about 6 h in a thermal flux of 2.29 x 10(12) n/cm2/s. The accuracy of the method was established by analyzing standard reference materials. Twenty-nine elements, Ag, As, Au, Ba, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Mn, Mo, Na, Rb, Sb, Sc, Se, Sm, Sr, Th, U, Yb, and Zn, were measured in all the samples, and Hg was detected in some samples, with good accuracy and reproducibility. The concentration of elements determined was found to vary depending on the composition of the herbs used. Although the trend linking the element of the medicinal plants to its curative abilities could not be clearly determined, this study showed that the toxic elements found in the samples were below the levels prescribed by health regulations. Nevertheless, such data are important to understand the pharmacological action and the exact mechanisms of action and formation of active constituents for each medicinal plant and to decide the dosage of the herbs used in the final formulation.
  4. Fulltext Effects of Genotype by Environment Interaction on Genetic Gain and Genetic Parameter Estimates in Red Tilapia (Oreochromis spp.)
    Nguyen NH, Hamzah A, Thoa NP
    Front Genet, 2017;8:82.
    PMID: 28659970 DOI: 10.3389/fgene.2017.00082
    The extent to which genetic gain achieved from selection programs under strictly controlled environments in the nucleus that can be expressed in commercial production systems is not well-documented in aquaculture species. The main aim of this paper was to assess the effects of genotype by environment interaction on genetic response and genetic parameters for four body traits (harvest weight, standard length, body depth, body width) and survival in Red tilapia (Oreochromis spp.). The growth and survival data were recorded on 19,916 individual fish from a pedigreed population undergoing three generations of selection for increased harvest weight in earthen ponds from 2010 to 2012 at the Aquaculture Extension Center, Department of Fisheries, Jitra in Kedah, Malaysia. The pedigree comprised a total of 224 sires and 262 dams, tracing back to the base population in 2009. A multivariate animal model was used to measure genetic response and estimate variance and covariance components. When the homologous body traits in freshwater pond and cage were treated as genetically distinct traits, the genetic correlations between the two environments were high (0.85-0.90) for harvest weight and square root of harvest weight but the estimates were of lower magnitudes for length, width and depth (0.63-0.79). The heritabilities estimated for the five traits studied differed between pond (0.02 to 0.22) and cage (0.07 to 0.68). The common full-sib effects were large, ranging from 0.23 to 0.59 in pond and 0.11 to 0.31 in cage across all traits. The direct and correlated responses for four body traits were generally greater in pond than in cage environments (0.011-1.561 vs. -0.033-0.567 genetic standard deviation units, respectively). Selection for increased harvest body weight resulted in positive genetic changes in survival rate in both pond and cage culture. In conclusion, the reduced selection response and the magnitude of the genetic parameter estimates in the production environment (i.e., cage) relative to those achieved in the nucleus (pond) were a result of the genotype by environment interaction and this effect should be taken into consideration in the future breeding program for Red tilapia.
  5. Fulltext Semi-analytical modelling and evaluation of uniformly doped silicene nanotransistors for digital logic gates
    Chuan MW, Wong KL, Riyadi MA, Hamzah A, Rusli S, Alias NE, et al.
    PLoS One, 2021;16(6):e0253289.
    PMID: 34125874 DOI: 10.1371/journal.pone.0253289
    Silicene has attracted remarkable attention in the semiconductor research community due to its silicon (Si) nature. It is predicted as one of the most promising candidates for the next generation nanoelectronic devices. In this paper, an efficient non-iterative technique is employed to create the SPICE models for p-type and n-type uniformly doped silicene field-effect transistors (FETs). The current-voltage characteristics show that the proposed silicene FET models exhibit high on-to-off current ratio under ballistic transport. In order to obtain practical digital logic timing diagrams, a parasitic load capacitance, which is dependent on the interconnect length, is attached at the output terminal of the logic circuits. Furthermore, the key circuit performance metrics, including the propagation delay, average power, power-delay product and energy-delay product of the proposed silicene-based logic gates are extracted and benchmarked with published results. The effects of the interconnect length to the propagation delay and average power are also investigated. The results of this work further envisage the uniformly doped silicene as a promising candidate for future nanoelectronic applications.
  6. Fulltext Modeling the Impact of Phonon Scattering with Strain Effects on the Electrical Properties of MoS2 Field-Effect Transistors
    Chin HC, Hamzah A, Alias NE, Tan MLP
    Micromachines (Basel), 2023 Jun 12;14(6).
    PMID: 37374820 DOI: 10.3390/mi14061235
    Molybdenum disulfide (MoS2) has distinctive electronic and mechanical properties which make it a highly prospective material for use as a channel in upcoming nanoelectronic devices. An analytical modeling framework was used to investigate the I-V characteristics of field-effect transistors based on MoS2. The study begins by developing a ballistic current equation using a circuit model with two contacts. The transmission probability, which considers both the acoustic and optical mean free path, is then derived. Next, the effect of phonon scattering on the device was examined by including transmission probabilities into the ballistic current equation. According to the findings, the presence of phonon scattering caused a decrease of 43.7% in the ballistic current of the device at room temperature when L = 10 nm. The influence of phonon scattering became more prominent as the temperature increased. In addition, this study also considers the impact of strain on the device. It is reported that applying compressive strain could increase the phonon scattering current by 13.3% at L = 10 nm at room temperature, as evaluated in terms of the electrons' effective masses. However, the phonon scattering current decreased by 13.3% under the same condition due to the existence of tensile strain. Moreover, incorporating a high-k dielectric to mitigate the impact of scattering resulted in an even greater improvement in device performance. Specifically, at L = 6 nm, the ballistic current was surpassed by 58.4%. Furthermore, the study achieved SS = 68.2 mV/dec using Al2O3 and an on-off ratio of 7.75 × 104 using HfO2. Finally, the analytical results were validated with previous works, showing comparable agreement with the existing literature.
  7. Fulltext Device performances analysis of p-type doped silicene-based field effect transistor using SPICE-compatible model
    Chuan MW, Riyadi MA, Hamzah A, Alias NE, Mohamed Sultan S, Lim CS, et al.
    PLoS One, 2022;17(3):e0264483.
    PMID: 35239699 DOI: 10.1371/journal.pone.0264483
    Moore's Law is approaching its end as transistors are scaled down to tens or few atoms per device, researchers are actively seeking for alternative approaches to leverage more-than-Moore nanoelectronics. Substituting the channel material of a field-effect transistors (FET) with silicene is foreseen as a viable approach for future transistor applications. In this study, we proposed a SPICE-compatible model for p-type (Aluminium) uniformly doped silicene FET for digital switching applications. The performance of the proposed device is benchmarked with various low-dimensional FETs in terms of their on-to-off current ratio, subthreshold swing and drain-induced barrier lowering. The results show that the proposed p-type silicene FET is comparable to most of the selected low-dimensional FET models. With its decent performance, the proposed SPICE-compatible model should be extended to the circuit-level simulation and beyond in future work.
  8. Youth hedonistic behaviour: moderating role of peer attachment on the effect of religiosity and worldview
    Hamzah SR, Suandi T, Krauss SE, Hamzah A, Tamam E
    Int J Adolesc Youth, 2014 Oct 2;19(4):419-433.
    PMID: 25431513
    This study was carried out on the moderating effect of peer attachment on the relationships between religiosity and worldview, and on how hedonistic behaviour among Malaysian undergraduate students is shaped by such influences. With regard to peer attachment, the study focused on the influences of communication, trust and alienation among youth. Bronfenbrenner's theory of human ecology and Armsden and Greenberg's attachment model were used as the framework. Drawing on a quantitative survey of 394 Malaysian university students (M age = 21.0, SD = 0.40), structural equation modelling and path analysis revealed a significant relationship between worldview and hedonistic behaviour. Peer attachment moderated the relationships between religiosity and religious worldview. The results further showed that the unique moderating effect of the lower level of attachment with peers is positively related to the hedonistic behaviour. Implications from the findings are discussed.
  9. Malaysianol B, an oligostilbenoid derivative from Dryobalanops lanceolata
    Wibowo A, Ahmat N, Hamzah AS, Low AL, Mohamad SA, Khong HY, et al.
    Fitoterapia, 2012 Dec;83(8):1569-75.
    PMID: 22982329 DOI: 10.1016/j.fitote.2012.09.004
    A new oligostilbenoid tetramer, malaysianol B (1), was isolated from the acetone extract of the stem bark of Dryobalanops lanceolata along with seven oligostilbenoids tetramers; hopeaphenol (2), stenophyllol A (3), nepalensinol B (4), vaticanol B (5) and C (6), upunaphenol D (7), and flexuosol A (8). The structures of the isolated compounds were established on the basis of their spectroscopic data evidence. The antibacterial activity of the isolated compounds was evaluated using resazurin microtitre-plate assay.
  10. Malaysianol A, a new trimer resveratrol oligomer from the stem bark of Dryobalanops aromatica
    Wibowo A, Ahmat N, Hamzah AS, Sufian AS, Ismail NH, Ahmad R, et al.
    Fitoterapia, 2011 Jun;82(4):676-81.
    PMID: 21338657 DOI: 10.1016/j.fitote.2011.02.006
    A new resveratrol trimer, malaysianol A (1), five known resveratrol oligomers: laevifonol (2), ampelopsin E (3), α-viniferin (4), ε-viniferin (5), diptoindonesin A (6), and bergenin (7) have been isolated from the acetone extract of the stem bark of Dryobalanops aromatica by combination of vacuum and radial chromatography techniques. Their structures were established on the basis of their spectroscopic evidence and comparison with the published data. The cytotoxic activity of the compounds was tested against several cell lines in which compound 4 was found to inhibit strongly the growth of HL-60 cell line.
  11. Evaluation of antioxidant and nitric oxide inhibitory activities of selected Malaysian medicinal plants
    Saha K, Lajis NH, Israf DA, Hamzah AS, Khozirah S, Khamis S, et al.
    J Ethnopharmacol, 2004 Jun;92(2-3):263-7.
    PMID: 15138010
    Methanol extracts of seven Malaysian medicinal plants were screened for antioxidant and nitric oxide inhibitory activities. Antioxidant activity was measured by using FTC, TBA and DPPH free radical scavenging methods and Griess assay was used for the measurement of nitric oxide inhibition in lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma)-treated RAW 264.7 cells. All the extracts showed strong antioxidant activity comparable to or higher than that of alpha-tocopherol, BHT and quercetin in FTC and TBA methods. The extracts from Leea indica and Spermacoce articularis showed strong DPPH free radical scavenging activity comparable with quercetin, BHT and Vit C. Spermacoce exilis showed only moderate activity but other species were weak as compared to the standards. In the Griess assay Lasianthus oblongus, Chasalia chartacea, Hedyotis verticillata, Spermacoce articularis and Leea indica showed strong inhibitory activity on nitric oxide production in LPS and IFN-gamma-induced RAW 264.7 cells. Extracts from Psychotria rostrata and Spermacoce exilis also inhibited NO production but this was due to their cytotoxic effects upon cells during culture.
  12. Fulltext Benzylidene derivatives of andrographolide inhibit growth of breast and colon cancer cells in vitro by inducing G(1) arrest and apoptosis
    Jada SR, Matthews C, Saad MS, Hamzah AS, Lajis NH, Stevens MF, et al.
    Br J Pharmacol, 2008 Nov;155(5):641-54.
    PMID: 18806812 DOI: 10.1038/bjp.2008.368
    BACKGROUND AND PURPOSE: Andrographolide, the major phytoconstituent of Andrographis paniculata, was previously shown by us to have activity against breast cancer. This led to synthesis of new andrographolide analogues to find compounds with better activity than the parent compound. Selected benzylidene derivatives were investigated for their mechanisms of action by studying their effects on the cell cycle progression and cell death.
    EXPERIMENTAL APPROACH: Microculture tetrazolium, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and sulphorhodamine B (SRB) assays were utilized in assessing the in vitro growth inhibition and cytotoxicity of compounds. Flow cytometry was used to analyse the cell cycle distribution of control and treated cells. CDK1 and CDK4 levels were determined by western blotting. Apoptotic cell death was assessed by fluorescence microscopy and flow cytometry.
    KEY RESULTS: Compounds, in nanomolar to micromolar concentrations, exhibited growth inhibition and cytotoxicity in MCF-7 (breast) and HCT-116 (colon) cancer cells. In the NCI screen, 3,19-(2-bromobenzylidene) andrographolide (SRJ09) and 3,19-(3-chloro-4-fluorobenzylidene) andrographolide (SRJ23) showed greater cytotoxic potency and selectivity than andrographolide. SRJ09 and SRJ23 induced G(1) arrest and apoptosis in MCF-7 and HCT-116 cells, respectively. SRJ09 downregulated CDK4 but not CDK1 level in MCF-7 cells. Apoptosis induced by SRJ09 and SRJ23 in HCT-116 cells was confirmed by annexin V-FITC/PI flow cytometry analysis.
    CONCLUSION AND IMPLICATIONS: The new benzylidene derivatives of andrographolide are potential anticancer agents. SRJ09 emerged as the lead compound in this study, exhibiting anticancer activity by downregulating CDK4 to promote a G(1) phase cell cycle arrest, coupled with induction of apoptosis.
  13. Fulltext Prevalence of wheeze, night cough and doctor-diagnosed asthma in pre-school children in Kota Bharu
    Quah BS, Mazidah AR, Hamzah AM, Simpson H
    Asian Pac J Allergy Immunol, 2000 Mar;18(1):15-21.
    PMID: 12546053
    While many studies of the prevalence of wheeze have been conducted in schoolchildren, there have been few in pre-school children. Most children with asthma develop symptoms before the age of 5 years and many pre-school wheezers continue to wheeze in the early school years. Among the latter, those children who continue to wheeze at school age have poorer lung function than those who don't. It is thus appropriate to enquire more fully about wheeze in this age-group where its incidence is high and its relation with asthma less well defined. The objective of this study was to investigate the prevalences of wheeze, night cough and doctor diagnosed asthma in pre-school children. A cross-sectional study was conducted in five primary health clinics in the district of Kota Bharu from April to October 1998. Nurses from these clinics distributed Bahasa Malaysia questionnaires containing questions on asthma symptoms to preschool children aged 1-5 years during their home visits. The respondents were parent(s) or carer(s) of the child. The response rate was 100% and a total of 2,878 responses were analysed. The prevalence of symptoms and doctor diagnosed asthma were as follows: ever wheezed 9.4% (95% confidence interval (CI) 8.3-10.4%); current wheeze 6.2% (95% CI 5.2 to 7.0%); night cough 10.2% (95% CI 9.1 to 11.4%); and doctor diagnosed asthma 7.1% (95% CI 6.2 to 8.0%). There were no significant differences in prevalence between males and females, or among age groups. The prevalence of night cough in children with no history of wheeze was 6.9%. The cumulative and current prevalences of wheeze were similar to, and those of night cough and doctor-diagnosed asthma significantly lower than, those reported for Kelantan schoolchildren. These findings provide a baseline for assessing future symptoms trends, and perhaps also the validity of diagnosing asthma in this age group.
  14. Fulltext Transcatheter Closure of Patent Ductus Arteriosus: The Penang Hospital's Experience
    Amir Hamzah AR, Tiow CA, Koh GT, Sharifah AM
    Med J Malaysia, 2011 Mar;66(1):19-21.
    PMID: 23765137
    Transcatheter closure of small and moderate sizes of Patent Ductus Arteriosus (PDA) is a standard and well accepted form of treatment. The aim of this study is to describe the experience of transcatheter closure of PDA in Penang Hospital. All patients who underwent transcatheter closure of PDA at our institution between 20th January 2006 and 27th June 2008 were retrospectively identified and studied. There were a total of 66 patients who had undergone transcatheter closure of PDA during this period which comprised of 24 male and 42 female. The PDA was closed by Amplatzer Duct Occluder (ADO) in 31 patients, Gianturco coil in 29 patients and other types of devices in 6 patients. There were 4 patients (6%) who had developed acute complication during the procedure (3 of them developed coil embolization and 1 had bleeding from puncture site). The PDA was successfully close in 95.5% of the study population without any residual PDA shunting. All the patients were alive but 5 of them (4.5%) have some abnormalities (2 has mild left pulmonary stenosis, 3 has small residual). Comparison between ADO and Gianturco coil revealed no significant difference in the outcome. Transcatheter closure of PDA has proven to be safe and effective with good midterm outcome. There was no significant difference between Amplatzer Ductal Occluder and Gianturco coil in term of the outcome.
  15. Kaempferitrin from the leaves of Hedyotis verticillata and its biological activity
    Hamzah AS, Lajis NH, Sargent MV
    Planta Med, 1994 Aug;60(4):388-9.
    PMID: 7938277
  16. Rare middle ear anomaly in a patient with Turner's syndrome
    Hamzah AR, Jalaluddin MA, Raman R
    Ann Otol Rhinol Laryngol, 1999 Mar;108(3):253-4.
    PMID: 10086617
    A patient with Turner's syndrome presented with a rare anomaly of absent oval window, inferiorly placed facial nerve, and abnormal stapes. To our knowledge, this is the first report of this combination of malformations.
  17. Expression, purification and kinetic characterization of recombinant benzoate dioxygenase from Rhodococcus ruber UKMP-5M
    Tavakoli A, Hamzah A, Rabu A
    Mol Biol Res Commun, 2016 Sep;5(3):133-142.
    PMID: 28097167
    In this study, benzoate dioxygenase from Rhodococcus ruber UKMP-5M was catalyzed by oxidating the benzene ring to catechol and other derivatives. The benzoate dioxygenase (benA gene) from Rhodococcus ruber UKMP-5M was then expressed, purified, characterized, The benA gene was amplified (642 bp), and the product was cloned into a pGEM-T vector. The recombinant plasmid pGEMT-benA was digested by double restriction enzymes BamHI and HindIII to construct plasmid pET28b-benA and was then ligated into Escherichia coli BL21 (DE3). The recombinant E. coli was induced with 0.5 mM isopropyl β-D-thiogalactoside (IPTG) at 22˚C to produce benzoate dioxygenase. The enzyme was then purified by ion exchange chromatography after 8 purification folds. The resulting product was 25 kDa, determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and western blotting. Benzoate dioxygenase activity was found to be 6.54 U/mL and the optimal pH and temperature were 8.5 and 25°C, respectively. Maximum velocity (Vmax) and Michaelis constant (Km) were 7.36 U/mL and 5.58 µM, respectively. The end metabolite from the benzoate dioxygenase reaction was cyclohexane dione, which was determined by gas chromatography mass spectrometry (GC-MS).
  18. Genetic variation and correlated changes in reproductive performance of a red tilapia line selected for improved growth over three generations
    Thoa NP, Hamzah A, Nguyen NH
    Anim. Reprod. Sci., 2017 Sep;184:94-101.
    PMID: 28709735 DOI: 10.1016/j.anireprosci.2017.07.003
    The present study examines genetic variation and correlated changes in reproductive performance traits in a red tilapia (Oreochromis spp.) population selected over three generations for improved growth. A total of 328 breeding females (offspring of 111 sires and 118 dams) had measurements of body weight prior to spawning (WBS), number of fry at hatching (NFH), total fry weight (TFW) and number of dead fry (NDF) or mortality of fry including unhatched eggs at hatching (MFH). Restricted maximum likelihood (REML) analysis in a multi-trait model showed that there are heritable genetic components for all traits studied. The heritability for WBS was very high (0.80). The estimates for traits related to fecundity (NFH, TFW) and survival (NDF) were low and they were associated with high standard errors. Genetic correlations of WBS with other reproductive performance traits (NFH, TFW and NDF) were generally positive. However, NFH was negatively correlated genetically with TFW. As expected, body measurements during growth stage exhibited strong positive genetic correlations with WBS. The genetic correlations between body traits and reproductive performance (NFH, TFW, NDF) were not significant. Correlated responses in reproductive traits were measured as changes in least squares means between generations or spawning years. Except for WBS that increased with the selection programs, the phenotypic changes in other reproductive traits observed were not statistically significant (P>0.05). It is concluded that the selection program for red tilapia has resulted in very little changes in reproductive performance of the animals after three generations. However, periodic monitoring of genetic changes in fecundity and fitness related traits such as NDF or MFH should be made in selective breeding programs for red tilapia.
  19. Genetic analysis of a red tilapia (Oreochromis spp.) population undergoing three generations of selection for increased body weight at harvest
    Hamzah A, Thoa NP, Nguyen NH
    J Appl Genet, 2017 Nov;58(4):509-519.
    PMID: 28980200 DOI: 10.1007/s13353-017-0411-8
    Quantitative genetic analysis was performed on 10,919 data records collected over three generations from the selection programme for increased body weight at harvest in red tilapia (Oreochromis spp.). They were offspring of 224 sires and 226 dams (50 sires and 60 dams per generation, on average). Linear mixed models were used to analyse body traits (weight, length, width and depth), whereas threshold generalised models assuming probit distribution were employed to examine genetic inheritance of survival rate, sexual maturity and body colour. The estimates of heritability for traits studied (body weight, standard length, body width, body depth, body colour, early sexual maturation and survival) across statistical models were moderate to high (0.13-0.45). Genetic correlations among body traits and survival were high and positive (0.68-0.96). Body length and width exhibited negative genetic correlations with body colour (- 0.47 to - 0.25). Sexual maturity was genetically correlated positively with measurements of body traits (weight and length). Direct and correlated genetic responses to selection were measured as estimated breeding values in each generation and expressed in genetic standard deviation units (σG). The cumulative improvement achieved for harvest body weight was 1.72 σG after three generations or 12.5% per generation when the gain was expressed as a percentage of the base population. Selection for improved body weight also resulted in correlated increase in other body traits (length, width and depth) and survival rate (ranging from 0.25 to 0.81 genetic standard deviation units). Avoidance of black spot parent matings also improved the overall red colour of the selected population. It is concluded that the selective breeding programme for red tilapia has succeeded in achieving significant genetic improvement for a range of commercially important traits in this species, and the large genetic variation in body colour and survival also shows that there are prospects for future improvement of these traits in this population of red tilapia.
  20. Fulltext The Effect of Ethnicity on Wideband Absorbance of Neonates with Healthy Middle Ear Functions in Malaysia: A Preliminary Study
    Wali HA, Mazlan R
    J Audiol Otol, 2018 Jan;22(1):20-27.
    PMID: 29061035 DOI: 10.7874/jao.2017.00227
    BACKGROUND AND OBJECTIVES: Although ethnicity effect on wideband absorbance (WBA) findings was evident for adults, its effect on neonates has not been established yet. This study aimed to investigate the influence of ethnicity on WBA measured at 0 daPa from neonates with healthy middle ear functions.

    SUBJECTS AND METHODS: Participants were 99 normal, healthy, full-term newborn babies with chronological age between 11 and 128 hours of age (mean=46.73, standard deviation=26.36). A cross-sectional study design was used to measure WBA at 16 one-third octave frequency points from 99 neonates comprising of three ethnic groups: Malays (n=58), Chinese (n=13) and Indians (n=28). A total of 165 ears (83.3%) that passed a battery of tests involving distortion product otoacoustic emissions, 1 kHz tympanometry and acoustic stapedial reflex were further tested using WBA. Moreover, body size measurements were recorded from each participant.

    RESULTS: The Malays and Indians neonates showed almost identical WBA response across the frequency range while the Chinese babies showed lower absorbance values between 1.25 kHz and 5 kHz. However, the differences observed in WBA between the three ethnic groups were not statistically significant (p=0.23). Additionally, there were no statistically significant difference in birth weight, height and head circumference among the three ethnic groups.

    CONCLUSIONS: This study showed that Malays, Chinese and Indians neonates were not significantly different in their WBA responses. In conclusion, to apply for the ethnic-specific norms is not warranted when testing neonates from population constitute of these three ethnicities.

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