Displaying publications 1 - 20 of 191 in total

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  1. Fulltext Blast injuries of the ear
    Singh AP, Prasad U, Kumar N
    Singapore Med J, 1983 Dec;24(6):367-73.
    PMID: 6681493
    Clinical synopsis and investigations on fourteen patients with blast injuries of the ear successfully treated at the ENT Unit of the University Hospital, Kuala Lumpur, revealed few interesting observations in addition to usual findings. The most outstanding one was the absence of sensorineural deafness, although it has been claimed as one of the most constant features. Conservative management alone was found to be of significant value.
    Matched MeSH terms: Hearing Loss, Noise-Induced/diagnosis*
  2. Noise and light hazards in modern industry
    Goh CS
    Family Practitioner, 1984;7:39-43.
    Matched MeSH terms: Noise
  3. Effects of noise in the workplace
    Noor Hassim I
    Family Physician, 1991;3:14-16.
    Matched MeSH terms: Noise
  4. Fulltext The noise exposed factory workers: the prevalence of sensori-neural hearing loss and their use of personal hearing protection devices
    Maisarah SZ, Said H
    Med J Malaysia, 1993 Sep;48(3):280-5.
    PMID: 8183139
    A total of 524 industrial workers were studied. They consisted of 442 noise exposed and 82 non-noise exposed workers. The purpose was to compare the prevalence of sensori-neural hearing loss among the noise exposed and the non-noise exposed workers, to study their knowledge on the hazard of noise to hearing and the workers' attitude towards the hearing protection devices. The prevalence of sensori-neural hearing loss was significantly higher among the noise exposed workers, i.e., 83% versus 31.7% (p < 0.01). However, the prevalence of hearing impairment was much lower for both groups, being 30.1% for the noise exposed and 3.7% for the non-noise exposed group. Although hearing protection devices were provided to 80.5% of the workers, only 5.1% were wearing them regularly. The possibility of developing hearing loss due to exposure to excessive noise was only known by 35.5% of the noise exposed workers. This awareness was found to have a positive correlation with the workers' compliance to the hearing protection devices. Our findings highlight the need for workers to be educated on the hazards of excessive noise exposure to hearing.
    Matched MeSH terms: Hearing Loss, Noise-Induced/epidemiology*
  5. Pure-tone audiometry and auditory brainstem responses in noise-induced deafness
    Noorhassim I, Kaga K, Nishimura K
    Am J Otolaryngol, 1996 1 1;17(1):31-5.
    PMID: 8801813
    PURPOSE: The objective of this study is to find the relationship between pure-tone audiometry results and the auditory brainstem response wave abnormalities.

    SUBJECTS AND METHODS: The pure-tone audiometry (PTA) and auditory brainstem responses (ABRs) from 22 patients (44 ears) with diagnosed noise-induced permanent hearing loss were studied. Three indices of PTA were average thresholds of 0.5 kHz/, /1 kHz, and 2 kHz (PTA1); 2 kHz and 4 kHz (PTA2); and 4 kHz (PTA3) were subdivided into 3 thresholds of hearing. Their relationships with ABR results were analysed. The patterns of PTA from various groups of ABR wave patterns were studied.

    RESULTS: In this study, the abnormal ABR wave patterns were detected in 72.7% of the ears. The ears with prolonged ABR wave latency, absent early waves, prolong interpeak wave I-V latency was 20.5%, 18.2%, and 21.1%, respectively. Normal ABRs were recorded in 27.3% of the ears despite marked thresholds elevation of the PTA at high frequencies. Other relationships between PTA results and ABR wave results were discussed.

    CONCLUSION: There were relationships between severity of noise-induced hearing loss indicated by PTA and the patterns of ABR wave abnormalities among workers with noise-induced permanent hearing loss.

    Matched MeSH terms: Hearing Loss, Noise-Induced/diagnosis*
  6. High performance liquid chromatography in phytochemical analysis of Eurycoma longifolia
    Chan KL, Choo CY, Morita H, Itokawa H
    Planta Med, 1998 Dec;64(8):741-5.
    PMID: 17253320 DOI: 10.1055/s-2006-957570
    An analytical method using HPLC with UV detection was developed to investigate the quassinoid content of Eurycoma longifolia Jack (Simaroubaceae) collected from various sources. Eurycomanone (1), longilactone (2), 14,15beta-dihydroxyklaineanone (3), 15beta-acetyl-14-hydroxyklaineanone (4), 6alpha-hydroxyeurycomalactone (5), and eurycomalactone (7) were isolated as reference standards and together with the synthesized 1beta,12alpha,15beta-triacetyleurycomanone (6, internal standard), were identified by NMR, MS, UV and IR spectroscopies. Their coefficient of variation values for 0.50-35 microg ml(-1) concentrations of quassinoids and their retention times measured within- and between-day were small. The recoveries of the spiked quassinoids in E. longifolia samples and their detection limits at 8.5 times signal to noise ratio were 99.75-109.13% and 0.01 microg ml(-1), respectively. From the root samples analysed, 1 had the highest concentration, being about 16.8-39.6 fold higher than the other quassinoids 2, 3, 5, 7 but 145.3 fold higher than 4 which showed the lowest concentration.
    Matched MeSH terms: Signal-To-Noise Ratio
  7. Effect of acute noise stress on acetylcholinesterase activity in discrete areas of rat brain
    Sembulingam K, Sembulingam P, Namasivayam A
    Indian J Med Sci, 2003 Nov;57(11):487-92.
    PMID: 14646156
    Effect of various stressor agents on the adrenergic system in brain had been studied extensively. However, reports on the effect of stress on various parameters of central cholinergic system are scanty. And very little is known about the effect of noise stress on the cholinergic system in brain. Hence, it was decided to elucidate the effect of acute noise stress on the activity of the enzyme acetylcholinesterase in discrete areas of brain in albino rats. Male albino rats of Wistar strain were subjected to acute noise stress for 30 minutes. The noise of pure sine wave tone was produced by using a function generator and was amplified. The frequency of noise generated was 1 kHz and the intensity was set at 100 dB. The total acetylcholinesterase activity was determined in the tissues of cerebral cortex, corpus striatum, hypothalamus and hippocampus of brain in these rats. The enzyme activity was estimated by colorimetric method using acetylthiocholine iodide as the substrate. The values were compared with the enzyme activity in the control rats. The activity of the enzyme increased significantly in all the four regions of the brain in rats after exposure to noise stress for 30 minutes. The results of the study indicate that the exposure to acute noise stress could modulate the cholinergic system in these areas of brain in rat.
    Matched MeSH terms: Noise/adverse effects*
  8. Ergonomic study on the manual component insertion lines for occupational health and safety improvements
    Sen RN, Yeow PH
    Int J Occup Saf Ergon, 2003;9(1):57-74.
    PMID: 12636892
    The study aimed at reducing the occupational health and safety problems faced by the manual component insertion operators. Subjective and objective assessments, and direct observations were made in the printed circuit assembly factory. Simple and low-cost ergonomic interventions were implemented, that is, repairing chairs, reducing high workloads, assigning operators to a maximum of 2 workstations, confining machines that emitted bad smell and much noise, and providing finger work aids. The results of the interventions were reductions in operators' work discomforts, that is, chair discomfort (by 90%), high work stress, and discomfort due to profound change in their workstations. Their health hazards were also eliminated, that is, inhalation of toxic fumes, exposure to too much noise, and pain due to pressing sharp components.
    Matched MeSH terms: Noise, Occupational
  9. Image signal-to-noise ratio estimation using the autoregressive model
    Sim KS, Kamel NS
    Scanning, 2004 7 31;26(3):135-9.
    PMID: 15283250
    In the last two decades, a variety of techniques for signal-to-noise ratio (SNR) estimation in scanning electron microscope (SEM) images have been proposed. However, these techniques can be divided into two groups: first, SNR estimators of good accuracy, but based on impractical assumptions; second, estimators based on realistic assumptions but of poor accuracy. In this paper we propose the implementation of autoregressive (AR)-model interpolation as a solution to the problem. Unlike others, the proposed technique is based on a single SEM image and offers the required accuracy and robustness in estimating SNR values.
    Matched MeSH terms: Signal-To-Noise Ratio
  10. Image signal-to-noise ratio and noise variance estimation using autoregressive model
    Kamel NS, Sim KS
    Scanning, 2004 12 23;26(6):277-81.
    PMID: 15612204
    During the last three decades, several techniques have been proposed for signal-to-noise ratio (SNR) and noise variance estimation in images, with different degrees of success. Recently, a novel technique based on the statistical autoregressive model (AR) was developed and proposed as a solution to SNR estimation in scanning electron microscope (SEM) image. In this paper, the efficiency of the developed technique with different imaging systems is proven and presented as an optimum solution to image noise variance and SNR estimation problems. Simulation results are carried out with images like Lena, remote sensing, and SEM. The two image parameters, SNR and noise variance, are estimated using different techniques and are compared with the AR-based estimator.
    Matched MeSH terms: Signal-To-Noise Ratio
  11. Hearing loss in walkman users
    Sofia Jaffer, Mohd Shakil Razi
    Journal of Occupational Safety and Health, 2004;1(1):31-37.
    MyJurnal
    This retrospective study was conducted at the audiology clinic of UKM in the year 2000. It was intended to detect the effect of walkman on the hearing system of its users and to investigate whether distortion product otoacoustic emission test can provide an early and reliable sign of cochlear damage or not. Distortion product otoacoustic emission test helps to determine the function of outer hair cell. Outer hair cells get damaged with exposure to loud sound, drugs and aging. Thirty subjects (20 in the study group and 10 in the control group), between the ages of 19-25 years, who fulfilled all the criteria of selection, were investigated. There were two sets of criteria (general and specific). Anyone, in the control or study group, failing in any of these criteria was excluded from the study. According to the general criteria, it was essential for all the subjects to have clean ear canals, normal hearing at all the frequencies (250Hz- 8000Hz), normal middle ear function (Type A tympanogram), no middle ear problem, not used/using any ototoxic medicine, no family history of hearing loss, no history of ear surgery, not exposed to any form of loud noise like disco, concert, F1 racing or gun shooting. According to the special criteria it was essential for the subjects in the control group to have never used a walkman and those in the study group must have been using a walkman for at least 6 months. Comparison of distortion product emission levels between control and study groups revealed that emissions were significantly lower in the study group, across all the frequencies, suggesting outer hair cell damage in the walkman users. These differences reached level of statistical significance (p<0.05) at 2, 4, 6 and 8kHz. Using walkman at an intensity unsafe for hearing and a duration longer than recommended is suspected for the outer hair cell damage in our study group. Those using walkman for longer duration and higher intensity manifested much lower emission levels. Our study supports the literature that distortion product emission test is a much sensitive test than pure-tone audiometry, as it can detect cochlear damage long before it appears in an audiogram. It is recommended that people who are exposed to loud noise regularly should be monitored with distortion product emission test. It is suggested that the use of walkman.
    Study site: Audiology clinic, Pusat Perubatan Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
    Matched MeSH terms: Noise
  12. Fulltext Serum leptin and corticosterone levels after exposure to noise stress in rats
    Chandralekha G, Jeganathan R, Viswanathan, Charan JC
    Malays J Med Sci, 2005 Jan;12(1):51-6.
    PMID: 22605947
    Even though extensive studies have been conducted on the effect of noise exposure on hearing apparatus / auditory system, information on the effect of noise on the other body functions is sparse. The present study examined the effect of exposure of albino rats to acute and chronic noise stress on two important interlaced endocrine levels. In acute experiments the animals were exposed to 120 dB noise for a duration of 1, 2, 3 hrs. In chronic experiments the animals were exposed to noise for one hour daily for 30, 60 and 90 days. Plasma corticosterone and leptin levels were measured in these animals. There was significant elevation in the levels of corticosterone and leptin after exposure to noise stress. The elevation in corticosterone level after noise stress is in agreement with earlier reports. So noise acts like a stressor and elevates the secretion of the corticosterone, the stress hormone and leptin, the product of the ob gene there is an elevation in leptin levels after noise stress.
    Matched MeSH terms: Noise
  13. Autoregressive Wiener filtering in a scanning electron microscopy imaging system
    Sim KS, Kamel NS, Chuah HT
    Scanning, 2005 6 7;27(3):147-53.
    PMID: 15934507
    In this paper, we propose to use the autoregressive (AR)-based interpolator with Wiener filter and apply the idea to scanning electron microscope (SEM) images. The concept for combining the AR-based interpolator with Wiener filtering comes from the essential requirement of Wiener filtering for accurate and consistent estimation of the power of the noise in images prior to filter implementation. The resultant filter is called AR-Wiener filter. The proposed filter is embedded onto the frame grabber card of the scanning electron microscope (SEM) for real-time image processing. Different images are captured using SEM and used to compare the performances of the conventional Wiener and the proposed AR-Wiener technique.
    Matched MeSH terms: Noise
  14. Brillouin-Raman comb fiber laser with cooperative Rayleigh scattering in a linear cavity
    Zamzuri AK, Md Ali MI, Ahmad A, Mohamad R, Mahdi MA
    Opt Lett, 2006 Apr 01;31(7):918-20.
    PMID: 16599211
    We demonstrate a multiple-wavelength Brillouin comb laser with cooperative Rayleigh scattering that uses Raman amplification in dispersion-compensating fiber. The laser resonator is a linear cavity formed by reflector at each end of the dispersion-compensating fiber to improve the reflectivity of the Brillouin Stokes comb. Multiple Brillouin Stokes generation has been improved in terms of optical signal-to-noise ratio and power-level fluctuation between neighboring channels. Furthermore, the linewidth of the Brillouin Stokes is uniform within the laser output bandwidth.
    Matched MeSH terms: Signal-To-Noise Ratio
  15. A study on compliance to hearing conservation programme among industries in Negeri Sembilan, Malaysia
    Nor Saleha IT, Noor Hassim I
    Ind Health, 2006 Oct;44(4):584-91.
    PMID: 17085919
    Noise is one of the hazards faced by workers. A cross-sectional study was conducted among industries in Negeri Sembilan with the objective to assess their compliance to Hearing Conservation Programme (HCP). The other objectives of this study were to determine the factors influencing it and to show the industries' compliance to each element of the programme. It was also to identify the association between compliance to HCP and the prevalence of hearing impairment and standard threshold shift. Data for this study were collected using questionnaires sent by mail and also the results of the latest audiometric tests. A total of 167 industries were analysed for this study. It was found that 41.3% of these industries fully complied to the programme. It was also found that the industries preferred to provide hearing protection device (92.8%) and least complied to noise control (61.1%). There were significant associations (p<0.05) between compliance and number of employees, status of ownership and the presence of officer in charge of hearing conservation programme. Having at least 150 employees actually raised the compliance to HCP in two folds (beta = 0.717, OR = 2.048, C.I 95% = 1.063 to 3.944). The prevalences of hearing impairment and standard threshold shift were 23.9% and 5.2% respectively. There was no significant association between the prevalence for hearing impairment and compliance to HCP. The prevalence for standard threshold shift was inversely related to compliance. This study showed that compliance percentage need to be improved as an effort to prevent the hearing problems among workers exposed to noise.
    Matched MeSH terms: Hearing Loss, Noise-Induced/etiology; Hearing Loss, Noise-Induced/epidemiology; Hearing Loss, Noise-Induced/prevention & control*; Noise, Occupational/adverse effects*
  16. Fulltext Linguistic context effects in the speech perfection of Malay-speaking normal hearing young adults
    Cila Umat, Nahazatul Islia Jamari
    Jurnal Sains Kesihatan Malaysia, 2006;4(1):9-20.
    MyJurnal
    The study examined the use of linguistic contextual cues among native, Malay-speaking normal hearing young adults. Ten undergraduate students of Universiti Kebangsaan Malaysia participated in the study. All subjects had normal hearing with the average hearing threshold levels for the overall left and the right ears of 7.8 dB (SD 4.1). The Malay Hearing in Noise Test (MyHINT) materials were employed and presented to the subjects at an approximately 65 dBA presentation level. Testing was conducted in a sound field in three different listening conditions: in quiet, in noise with +5 dB signal-to-noise ratio (SNR) and 0 dB SNR. In every test condition, three lists of MyHINT were administered to each subject. The magnitude of context effects was measured using the j factor, which was derived from measurements of recognition probabilities for whole sentences (13,) and the constituent words in the sentences (PP) in which j = log P./ log P P. Results showed that all subjects scored 100% identification of words in sentences and whole sentences in quiet listening condition, while subjects' performances in 0 dB SNR were significantly poorer than that in quiet and in +5 dB SNR (p < 0.001). The j-values were significantly correlated with the probability of recognizing words in the sentences (r = 0.515, p = 0.029) in which lower j values were associated with lower P ps. Subjects were not significantly different from each other in their use of contextual cues in adverse listening conditions [F(9, 7) = 1.34, p = 0.359]. Using the linear regression function for j on word recognition probabilities, the predicted P. were calculated. It was found that the predicted and measured probabilities of recognizing whole sentences were highly correlated: r = 0.973, p < 0.001. The results suggested that linguistic contextual information become increasingly important for recognition of sentences by normal hearing young adult listeners as SNR deteriorates.
    Matched MeSH terms: Noise; Signal-To-Noise Ratio
  17. Fulltext Noise exposure and noise induced hearing loss among Kuala Lumpur traffic point duty personnel
    Thomas N, Mariah AN, Fuad A, Kuljit S, Philip R
    Med J Malaysia, 2007 Jun;62(2):152-5.
    PMID: 18705450 MyJurnal
    Thirty-two points in Kuala Lumpur were selected where traffic personnel were on duty. Sound level readings were taken three times a day. Generally, the traffic noise levels were between 75 dBA to 85 dBA. The maximum sound level recorded was 108.2 dBA. Noise emitted by traffic equipment and vehicles were up to 133 dBA. Results of audiometric tests revealed that out of 30 who were tested, 24 or 80% were positive for noise-induced hearing loss. A questionnaire survey revealed a lack of knowledge on occupational safety and personal protective equipment.
    Matched MeSH terms: Hearing Loss, Noise-Induced/etiology*; Hearing Loss, Noise-Induced/prevention & control; Noise, Occupational/adverse effects*; Noise, Transportation/adverse effects*
  18. Fulltext Noise exposure effect on testicular histology, morphology and on male steroidogenic hormone
    Swami CG, Ramanathan J, Charan Jeganath C
    Malays J Med Sci, 2007 Jul;14(2):28-35.
    PMID: 23515367 MyJurnal
    The noise stress, after it passes through the hearing apparatus, not only affects the auditory apparatus but also other body functions. The alterations in the levels of cortical hormone, adrenocorticosterone, nor-epinephrine hormone (which are primarily considered as stress hormones) on follicular stimulating hormone, testosterone, and lutinizing hormone were reported in relation with stress. Male albino rats weighing 200 to 250 grams were exposed to 100 dB of noise for one hour and three hours in acute group and daily one hour exposure for 60 day, and 90 day in chronic group. The serum testosterone levels were measured in these animals. There was significant reduction in serum testosterone levels and this was similar with earlier reports. The tissues were collected for light and confocal microscopic study. 100dB of traffic noise exposure of varying duration had definite permanent effect on testicular histology and morphology and on the male sex hormone. The adaptation mechanism was noticed at the hormonal level only but the structural changes noticed were definite and permanent. The agglutinated dead sperms revealed the possibility of infertily when chronically exposed to noise stress.
    Matched MeSH terms: Noise
  19. Fulltext An erbium/ytterbium co-doped fibre amplifier using 1058 nm pumping
    Harun, S.W., Tamjis, M.R., Muhd-Yassin, S.Z., Abd-Rahman, M.K., Ahmad, H.
    ASM Science Journal, 2007;1(2):129-133.
    MyJurnal
    This paper demonstrates an erbium/ytterbium co-doped fi bre amplifi er (EYDFA) which used a pumping wavelength of 1058 nm, whereby the amplifi cation was assisted by the energy transfer between Yb and Er ions. The energy transfer increased the erbium doping concentration limit that was imposed by concentration quenching in erbium-doped fi bre. The optimum length was obtained at 4m~6m for erbium/ytterbium co-doped fi bre with Er ion concentration of 1000 p.p.m. This enabled the development of a compact amplifi er with a shorter gain medium compared to erbium-doped fi bre amplifi ers which use a gain medium of up to 15 m. A 1058 nm pumping wave-length was used for the EYDFA, as 1480 nm pumping resulted in severely degraded gain and noise fi gures because the energy transfer could not be achieved. The use of the optical isolator improved the small signal gain and noise fi gure by about 4.8 dB and 1.6 dB, respectively. Without the isolator, gain saturation and a noise fi gure penalty were observed due to the oscillating laser which was created at around 1534 nm by spurious refl ection. This showed that the usage of optical isolators was an important aspect to consider when designing an EYDFA.
    Matched MeSH terms: Noise
  20. Fulltext Optical tomography: real time image reconstruction for various flow regimes in gravity flow conveyor
    Abdul Rahim, R., Pang, J.F., Chan, K.S., Leong, L.C., Fazalul Rahiman, M.H.
    ASM Science Journal, 2007;1(1):27-36.
    MyJurnal
    In this study, real-time imaging was monitored for flowing solid particles when various baffles were created to block certain areas of the pipe. The generated flow regimes were full-flow, three-quarter-flow, half-flow and quarter-flow. A vertical pneumatic conveyor was designed to hold a 85 mm inner diameter pipeline. The four projection optical tomography systems used, applied the parallel beam projection approach and use infrared light sources so that the sensor was free of noise from the surrounding visible light source. The two orthogonal and two rectilinear projections were axial, but ideally they should have been in the same layer. The sensor readings could be related to the varying light intensity effects of the dropping particles and were used to provide cross-sectional distribution information for the conveyor. By using computer programming, the information was reconstructed to produce coloured images and concentration was obtained by reference to a colour code. The results obtained from this study showed how imaged flow followed the artificial flow regime. This study could benefit industrial production lines in maintaining the desired flow rates.
    Matched MeSH terms: Noise
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