Displaying publications 1 - 20 of 106 in total

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  1. Kuan BB, Lim TK
    Med J Malaysia, 1984 Dec;39(4):280-4.
    PMID: 6544933
    Ultrasound measurement of ocular dimension is the chosen method for assessing axial length when determining dioptric power for intraocular lens. From the current results of 30 cases studied, the mean axial length ranges from 22 to 23 mm. Despite the limitation of the accuracy of the ultrasonic measurements with the 7.5 mHz transducer, the power of intraocular lens can. be determined satisfactorily in accordance with the knowledge of keratometric reading. Hence, high refractive errors could be avoided post-operatively.
    Matched MeSH terms: Ultrasonics*
  2. Gabriel R
    Malays J Reprod Health, 1992 Jun;10(1):19-22.
    PMID: 12345025
    PIP: Between December 1990 and May 1991 in Malaysia, clinicians at the Sultanah Aminah Hospital in Johor Bahru screened 200 women with a diagnosis of threatened miscarriage with ultrasound to determine whether ultrasound could evaluate the viability of the fetus and thus the outcome of pregnancy in cases of threatened abortion. A fetal heartbeat was absent in 65% of cases with the remaining 35% of cases having a fetal heartbeat. Nonviability of the fetus or an abnormal or very early pregnancy may have accounted for an absent fetal heartbeat. The pregnancy of 46% of cases continued while 41% experienced spontaneous abortion. Just 6.2% of cases with a fetal heartbeat suffered from spontaneous abortion compared with 69.7% of those without a fetal heartbeat. 93.8% of cases with a fetal heartbeat continued their pregnancies compared with 30.3% of those without a fetal heartbeat. Inability of ultrasound to detect fetal heartbeats during early pregnancy probably accounted for the somewhat high percentage of those without a fetal heartbeat who continued their pregnancies. Among patients with a fetal heartbeat, the number of pregnancies that continued. Ultrasound detected 13% abnormal pregnancies (i.e., molar pregnancy or ectopic pregnancy). Surgery on these cases confirmed the ultrasound findings. These results showed that ultrasound should be used in every case of threatened miscarriage and that a fetal heartbeat does indicate the viability of the fetus.
    Matched MeSH terms: Ultrasonics*
  3. Zainol H, Sumithran E
    Histopathology, 1993 Jun;22(6):581-6.
    PMID: 7689070
    This study evaluates the usefulness of a combined cytological and histological approach to the diagnosis of hepatocellular carcinoma (HCC) when applied to fine needle biopsy specimens obtained under ultrasonic guidance. The material, aspirated from 51 focal liver lesions, was handled in such a way that there was sufficient material for both cytological and histological (cell block) assessment. Of the 29 cases of HCC studied, a confident cytological diagnosis was made in 23 (79%). In the remaining six cases, the cytological features were considered to be suspicious but not diagnostic of HCC. Examination of cell blocks in the six cases enabled a confident diagnosis of HCC to be made in all cases. This was due to the supplementary visual information provided by the histological features, particularly the pattern of arrangement of the tumour cells.
    Matched MeSH terms: Ultrasonics
  4. Ling BC, Gillings BR
    Asian J Aesthet Dent, 1995;3:17-21.
    PMID: 9063105
    With the prognosis of dental implant replacement of missing teeth becoming better each year, practitioners are focusing their attention on the aesthetic aspects of implantology. However, improvement in aesthetics is only possible with the improvement in implant technology, surgical techniques and prosthodontic procedures. This study aimed at evaluating the effects of various physical and chemical agents on the implant surface; with the view of obtaining increased surface area and biocompatibility. The study found that the treatment of air-aluminum oxide blasted implants using a mixture of 30% HNO3-5% HF acids produced a surface which meets the consideration of aesthetics for implants placed in the anterior maxillary region.
    Matched MeSH terms: Ultrasonics
  5. Umar Hamzah, Ibrahim Komoo
    A survey to characterize seismic and ultrasonic properties of a granite weathering profile have been carried out at a roadcut slope exposure along Kuala Lumpur-Karak highway at kilometres 39.9. The terraced cut slope shows a complete weathering profile beginning from fresh grade I rock to grade VI residual soil. Together with in situ seismic measurement, rock samples have been collected for ultrasonic tests in laboratory. The range of velocities representing grades and indices of weathered rocks and soils are determined from the in situ seismic surveys. The range of ultrasonic velocities and elastic moduli are obtained from the laboratory measurements.
    Satu survei untuk mencirikan sifat seismos dan ultrasonik profil luluhawa granit telah dilakukan di singkapan potongan jalan, cerun utara lebuhraya Kuala Lumpur-Karak pada lokaliti 39.9 km. Potongan berteres ini mempamirkan satu profil luluhawa lengkap iaitu mulai batuan gred 1 yang segar hingga ke tanah baki bergred VI. Di samping pengukuran seismos secara in situ, sampel batuan juga diambil untuk dibuat pengukuran halaju ultrasonik di makmal. Julat halaju yang mewakili gred dan indeks luluhawa bagi tanah dan batuan diperolehi daripada survei seismos in situ. Julat halaju trasonik dan modulus kenyal diperolehi hasil pengukuran di makmal.
    Matched MeSH terms: Ultrasonics
  6. Show KY, Mao T, Lee DJ
    Water Res, 2007 Dec;41(20):4741-7.
    PMID: 17688907
    This study presents an examination on the correlation of sonication operating condition, sludge property, formation and behaviour of cavitation bubbles in sludge disruption under low-frequency ultrasound sonication. The influence of sonication time, sonication density, type of sludge and solids content on the disruption was evaluated. The most vigorous particle disruption was achieved in the initial period of sonication, which subsided subsequently. The explosive effect was likely due to the rapid cavitation arising from powerful transient bubbles generated in fractions of microseconds. A rating for the type of sludge was derived based on the finding that particles in secondary sludge were more readily disrupted than both primary sludge and mixed sludge. While sonication density exhibited the most significant role in cavitation bubble formation and behaviour, particle disruption could be optimised for energy input by sonicating at higher sonication density and shorter sonication time. Based on theoretical consideration, it was deduced that within an optimum sludge solids content ranging between 2.3% and 3.2%, superior particle disruption could be accomplished within a minute for secondary sludge sonicated at a density of 0.52 W/mL. Useful guidelines for sonication system installation, equipment protection and process reliability could be established from knowledge derived from a good understanding on the influence of solids content on sludge sonication.
    Matched MeSH terms: Ultrasonics
  7. Joseph CG, Li Puma G, Bono A, Krishnaiah D
    Ultrason Sonochem, 2009 Jun;16(5):583-9.
    PMID: 19282232 DOI: 10.1016/j.ultsonch.2009.02.002
    Sonophotocatalysis involves the use of a combination of ultrasonic sound waves, ultraviolet radiation and a semiconductor photocatalyst to enhance a chemical reaction by the formation of free radicals in aqueous systems. Researchers have used sonophotocatalysis in a variety of investigations i.e. from water decontamination to direct pollutant degradation. This degradation process provides an excellent opportunity to reduce reaction time and the amount of reagents used without the need for extreme physical conditions. Given its advantages, the sonophotocatalysis process has a futuristic application from an engineering and fundamental aspect in commercial applications. A detailed search of published reports was done and analyzed in this paper with respect to sonication, photocatalysis and advanced oxidation processes.
    Matched MeSH terms: Ultrasonics*
  8. Palaniandy, Samayamutthirian, Noorina Hidayu Jamil, Khairun Azizi Mohd Azizli, Syed Fuad Saiyid Hashim, Hashim Hussin
    MyJurnal
    Fine grinding of high purity talc in jet mill at low grinding pressure was carried out by varying the feed rate and classifier rotational speed. These ground particles were sonicated in laboratory ultrasonic bath by varying the soniction period at five levels. The ground and sonicated particles were characterized in terms of particle size and particle size distribution. Mechanochemical and sonochemical effect of talc was determine via X-ray diffraction. Particle shape and surface texture of the ground and sonicated product was determined via scanning electron microscope and transmission electron microscope. The ground particle size exhibited particle size below 10 µm with narrow size distribution. The reduction of peak intensity in (002) plane indicated the layered structure has been distorted. The sonicated talc shows that the thickness of the talc particles after the sonication process is 20 nm but the lateral particle size still remains in micron range. The reduction of the XRD peak intensity for (002) plane and thickness of sonicated talc as shown in SEM and TEM micrographs proves that fine grinding and sonication process produces talc nanosheets.
    Matched MeSH terms: Ultrasonics
  9. Zakaria, Z., Fazalul Rahiman, M.H., Abdul Rahim, R., Megat Ali, M.S.A., Baharuddin, M.Y., Jahidin, A.H.
    MyJurnal
    Ultrasound technology progressed through the 1960’s from simple A-mode and B-mode scans to today’s M-mode and Doppler two dimensional (2-D) and even three dimensional (3-D) systems. Modern ultrasound imaging has its roots in sonar technology after it was first described by Lord John Rayleigh over 100 years ago on the interaction of acoustic waves with media. Tomography technique was developed as a diagnostic tool in the medical area since the early of 1970’s. This research initially focused on how to retrieve a cross sectional images from living or non-living things. After a decade, the application of tomography systems span into the industrial area. However, the long exposure time of medical radiation-based method cannot tolerate the dynamic changes in industrial process two phase liquid/gas flow system.. An alternative system such as a process tomography system, can give information on the nature of the flow regime characteristic. The overall aim of this paper is to investigate the use of a small scale ultrasonic tomography method based on ultrasonic transmission mode tomography for online monitoring of liquid/gas flow in pipe/vessel system through ultrasonic transceivers application. This non-invasive technique applied sixteen transceivers as the sensing elements to cover the pipe/vessel cross section. The paper also details the transceivers selection criteria, hardware setup, the electronic measurement circuit and also the image reconstruction algorithm applied. The system was found capable of visualizing the internal characteristics and provides the concentration profile for the corresponding liquid and gas phases.
    Matched MeSH terms: Ultrasonics
  10. Mustapha, I., Takriff, M.S., Kamaruddin, S.K., Hassan, N.M., Zain, R.M.
    MyJurnal
    Electrical capacitance tomography (ECT) velocimetry technique was utilized in this study to quantify the flow structure of gas-liquid based on the ECT images. A new 8 electrodes sensor ECT has been successfully developed to provide 2D images in a cross section of pipeline. The ECT has been attentively applied in the test section of the flow rig for imaging the gas-liquid distribution. The inside diameter of ECT pipeline sensor is 100mm. Meanwhile, the flow rig consists of close loop of “CPVC” pipes that includes a pipe test section, two tanks of oil and water respectively and allows the working pressure up to 5 bars. Transparent pipe is used for visual monitoring. A portable Doppler flow meter that utilizes the ultrasonic signal has also been placed at the test section to measure the velocity. The images obtained by ECT show that the different flow patterns have been observed in the horizontal pipe during the experiment. The technique enables realization of the time and position at which particle density fluctuations with respect to dominant time-space levels pass through the pipeline.
    Matched MeSH terms: Ultrasonics
  11. Abdullah AZ, Ling PY
    J Hazard Mater, 2010 Jan 15;173(1-3):159-67.
    PMID: 19740600 DOI: 10.1016/j.jhazmat.2009.08.060
    The ambient sonocatalytic degradation of congo red, methyl orange, and methylene blue by titanium dioxide (TiO(2)) catalyst at initial concentrations between 10 and 50mg/L, catalyst loadings between 1.0 and 3.0mg/L and hydrogen peroxide (H(2)O(2)) concentrations up to 600 mg/L is reported. A 20 kHz ultrasonic processor at 50 W was used to accelerate the reaction. The catalysts were exposed to heat treatments between 400 and 1000 degrees C for up to 4h to induce phase change. Sonocatalysts with small amount of rutile phase showed better sonocatalytic activity but excessive rutile phase should be avoided. TiO(2) heated to 800 degrees C for 2h showed the highest sonocatalytic activity and the degradation of dyes was influenced by their chemical structures, chemical phases and characteristics of the catalysts. Congo red exhibited the highest degradation rate, attributed to multiple labile azo bonds to cause highest reactivity with the free radicals generated. An initial concentration of 10mg/L, 1.5 g/L of catalyst loading and 450 ppm of H(2)O(2) gave the best congo red removal efficiency of above 80% in 180 min. Rate coefficients for the sonocatalytic process was successfully established and the reused catalyst showed an activity drop by merely 10%.
    Matched MeSH terms: Ultrasonics*
  12. Yunus R, Salleh SF, Abdullah N, Biak DR
    Bioresour Technol, 2010 Dec;101(24):9792-6.
    PMID: 20719502 DOI: 10.1016/j.biortech.2010.07.074
    Various pre-treatment techniques change the physical and chemical structure of the lignocellulosic biomass and improve hydrolysis rates. The effect of ultrasonic pre-treatment on oil palm empty fruit bunch (OPEFB) fibre prior to acid hydrolysis has been evaluated. The main objective of this study was to determine if ultrasonic pre-treatment could function as a pre-treatment method for the acid hydrolysis of OPEFB fibre at a low temperature and pressure. Hydrolysis at a low temperature was studied using 2% sulphuric acid; 1:25 solid liquid ratio and 100 degrees C operating temperature. A maximum xylose yield of 58% was achieved when the OPEFB fibre was ultrasonicated at 90% amplitude for 45min. In the absence of ultrasonic pre-treatment only 22% of xylose was obtained. However, no substantial increase of xylose formation was observed for acid hydrolysis at higher temperatures of 120 and 140 degrees C on ultrasonicated OPEFB fibre. The samples were then analysed using a scanning electron microscope (SEM) to describe the morphological changes of the OPEFB fibre. The SEM observations show interesting morphological changes within the OPEFB fibre for different acid hydrolysis conditions.
    Matched MeSH terms: Ultrasonics/methods*
  13. Lau EV, Gan S, Ng HK
    Int J Anal Chem, 2010;2010:398381.
    PMID: 20396670 DOI: 10.1155/2010/398381
    This paper aims to provide a review of the analytical extraction techniques for polycyclic aromatic hydrocarbons (PAHs) in soils. The extraction technologies described here include Soxhlet extraction, ultrasonic and mechanical agitation, accelerated solvent extraction, supercritical and subcritical fluid extraction, microwave-assisted extraction, solid phase extraction and microextraction, thermal desorption and flash pyrolysis, as well as fluidised-bed extraction. The influencing factors in the extraction of PAHs from soil such as temperature, type of solvent, soil moisture, and other soil characteristics are also discussed. The paper concludes with a review of the models used to describe the kinetics of PAH desorption from soils during solvent extraction.
    Matched MeSH terms: Ultrasonics
  14. Suhaiza, A., Che Anuar, C.Y., Nik Zuky, N.L., Mokhtar, A.
    MyJurnal
    Monoamniotic twin pregnancy is a rare type of twin pregnancy which poses risk of cord entanglement and
    sudden death of either one or both fetuses. The role of antenatal surveillance by Ultrasound Doppler for
    umbilical cord and ultrasonic evidence of cord entanglement or knotting may predict the pregnancy outcome
    but yet unavoidable. The discussion will include antenatal surveillance in this rare type of pregnancy.
    Matched MeSH terms: Ultrasonics
  15. Sobhanzadeh E, Abu Bakar NK, Bin Abas MR, Nemati K
    J Hazard Mater, 2011 Feb 28;186(2-3):1308-13.
    PMID: 21177032 DOI: 10.1016/j.jhazmat.2010.12.001
    A simple and effective multiresidue method based on precipitation at low temperature followed by matrix solid-phase dispersion-sonication was developed and validated to determine dimethoate, malathion, carbaryl, simazine, terbuthylazine, atrazine and diuron in palm oil using liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS). Liquid-liquid extraction (LLE) followed by low temperature method were optimized by studying the effect of type and volume of organic solvent (acetonitrile, acetonitrile:n-hexane (3:2 v/v) and acetone) and time of freezing to obtain high recovery yield and low co-extract fat residue in the final extract. The optimal conditions for matrix solid-phase dispersion (MSPD) were obtained using 5 g of palm oil, 2 g of primary secondary amine (PSA) as dispersing sorbent, 1 g of graphitized carbon black (GCB) as clean-up sorbent and 15 mL of acetonitrile as eluting solvent under conditions of 15 min ultrasonication at room temperature. Method validation was performed in order to study sensitivity, linearity, precision, and accuracy. Average recoveries at three concentration levels (25, 50 and 100 μg kg(-1)) were found in the range of 72.6-91.3% with relative standard deviations between 5.3% and 14.2%. Detection and quantification limits ranged from 1.5 to 5 μg kg(-1) and from 2.5 to 9 μg kg(-1), respectively.
    Matched MeSH terms: Ultrasonics
  16. Bhat R, Kamaruddin NS, Min-Tze L, Karim AA
    Ultrason Sonochem, 2011 Nov;18(6):1295-300.
    PMID: 21550834 DOI: 10.1016/j.ultsonch.2011.04.002
    Freshly squeezed kasturi lime fruit juice was sonicated (for 0, 30 and 60min at 20°C, 25kHz frequency) to evaluate its impact on selected physico-chemical and antioxidant properties, such as pH, °Brix, titratable acidity, Hunter color values (L(∗), a(∗), b(∗)), ascorbic acid, DPPH radical scavenging activity, total phenolics, antioxidant capacity, flavonoids and flavonols. Additionally, the effect of sonication treatments on the microbial load (TPC, yeast and mold) were also evaluated. Sonication of juice samples for 60min showed enhancement in most of the bioactive compounds compared to samples treated for 30min and control samples (untreated). Significant reductions in the microbial load corresponding to sonication time were also recorded. Results of the present study indicate that sonication may be employed as a suitable technique for kasturi lime juice processing, where antioxidant and other bioactive compound retention or enhancement is desired, along with the achievement of safety and quality standards.
    Matched MeSH terms: Ultrasonics*
  17. Irfan Mohamad, Chentilnathan, Periasamy, Yahia, Dawood
    MyJurnal
    Pyogenic granuloma is a benign lesion which is commonly found in the oral cavity. It is a reactive inflammatory process of the injured mucosa to trauma. It can appear as a sessile or pedunculated mass with smooth or lobulated surface, which sometimes can mimic malignant lesion. Excision biopsy of the lesion is the confirmatory investigation which also a treatment tool. We report a case of middle-aged lady who had pyogenic granuloma of the tongue, which was safely excised using ultrasonic scissors. This case highlights the new technique of using ultrasonic instruments for excision of benign tongue lesion, with marked reduction of blood loss and operation time.
    Matched MeSH terms: Ultrasonics
  18. Ali, G., Russly, A.R., Jamilah, B., Azizah, O., Mandana, B.
    MyJurnal
    This study aims to evaluate the effect of heat and the simultaneous application of heat (80-95°C) and ultrasonic waves (thermosonication) on the inactivation kinetic of peroxidase and vitamin C degradation in seedless guava. Ultrasonic wave’s amplitudes except 25 and 100% had significant (P 0.98). In the heat blanching process, the peroxidase inactivation rate constant increased from 1.1×10-2 to 4.6×10-2 s-1. However, the inactivation rate of peroxidase was increased by 1.5–3 times in the temperature range 80–95ºC, with the 50 and 75% ultrasonic wave amplitudes, respectively. Decreases in vitamin C contents due to blanching treatments were found. Blanching processes at high temperature and short time resulted in higher vitamin C retention. It was found that thermosonication treatment inactivates seedless guava peroxidase at less severe blanching conditions and consequently retains vitamin C content at higher levels. The present findings will help to design the blanching conditions in order to reduce the severity of conventional thermal treatments and, therefore, improving the quality of the thermally treated product.
    Matched MeSH terms: Ultrasonics
  19. Goh T, Abdul Rahim Samsudin, Abdul Ghani Rafek
    A geotechnical study needs to be carried out to determine the engineering parameters of the rock mass at the project site in executing construction projects such as tunnels, dams, highways and buildings. Design and safety factor of the construction are highly dependent on soil and rock engineering parameters which are usually determined by in-situ test such as Standard Penetration Test (SPT) and seismic tests. The SPT test which normally involves drilling and laboratory works always incur high operating cost, while seismic tests on the other hand are fast, cheap, non-destructive and an easy to operate method for rock mass characterization. The spectral analysis of surface waves (SASW) method is an in situ and non-destructive measurement that is rapid and cost effective. The aims of this study were to determine Rock Quality Designation (RQD) value, excavation classification analysis as well as site characterization by using the SASW method. WinSASW 3.1.3 was used for inversion processing of the SASW data to produce shear wave velocity (Vs) versus depth profiles. The profiles were then analyzed and correlated with rock mass engineering geological parameters such as RQD and site characterization as well as excavation classification of rock mass. Twenty (20) SASW tests were conducted on the granitic rock mass and four (4) SASW tests were conducted on a cut hill slope of metasedimentary rocks. RQD values were computed based on shear wave velocities and ultrasonic velocities of intact (fresh) rock. The differences between RQD obtained from SASW method and those from discontinuity survey were found to be less than 10%. Excavation classification for granitic rock mass at JKR Quarry was empirically determined using both SASW and ultrasonic velocities as well as RQD value of the rock mass. Site characterization for metasedimentary rocks mass at Bukit Tampoi was determined based on shear wave velocities from SASW method.
    Matched MeSH terms: Ultrasonics
  20. Eh AL, Teoh SG
    Ultrason Sonochem, 2012 Jan;19(1):151-9.
    PMID: 21715212 DOI: 10.1016/j.ultsonch.2011.05.019
    Lycopene extraction was carried out via the ultrasonic assisted extraction (UAE) with response surface methodology (RSM). Sonication enhanced the efficiency of relative lycopene yield (enhancement of 26% extraction yield of lycopene in 6 replications at 40.0 min, 40.0 °C and 70.0% v/w in the presence of ultrasound), lowered the extraction temperature and shortened the total extraction time. The extraction was applied with the addition of oxygen-free nitrogen flow and change of water route during water bath sonication. The highest relative yield of lycopene obtained was 100% at 45.0 °C with total extraction time of 50.0 min (30:10:10) and ratio of solvent to freeze-dried tomato sample (v/w) of 80.0:1. Optimisation of the lycopene extraction had been performed, giving the average relative lycopene yield of 99% at 45.6 min, 47.6 °C and ratio of solvent to freeze-dried tomato sample (v/w) of 74.4:1. From the optimised model, the average yield of all-trans lycopene obtained was 5.11±0.27 mg/g dry weight. The all-trans lycopene obtained from the high-performance liquid chromatography (HPLC) chromatograms was 96.81±0.81% with 3.19±0.81% of cis-lycopenes. The purity of total-lycopene obtained was 98.27±0.52% with β-carotene constituted 1.73±0.52% of the extract. The current improved, UAE of lycopene from tomatoes with the aid of RSM also enhanced the extraction yield of trans-lycopene by 75.93% compared to optimised conventional method of extraction. Hence, the current, improved UAE of lycopene promotes the extraction yield of lycopene and at the same time, minimises the degradation and isomerisation of lycopene.
    Matched MeSH terms: Ultrasonics/instrumentation; Ultrasonics/methods*
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