Displaying publications 1 - 20 of 67 in total

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  1. Miniature radio-tracking studies of the hosts of vector mites in Malaysia
    Gentry JW
    J Med Entomol, 1965 Jun;2(2):153-6.
    PMID: 5827572
    Matched MeSH terms: Radio*
  2. The movement of radioactive albumin (I131 R.H.S.A.) from blood into C.S.F. and vice versa by dilution method in normal and Plasmodium knowlesi infected Macaca mulatta
    Migasena P, Maegraith BG
    Med J Malaya, 1968 Mar;22(3):250.
    PMID: 4234388
    Matched MeSH terms: Serum Albumin, Radio-Iodinated/blood; Serum Albumin, Radio-Iodinated/cerebrospinal fluid; Serum Albumin, Radio-Iodinated/metabolism*
  3. Factor affecting on the movement of protein across the blood: brain: C.S.F. barriers in Plasmodium knowlesi infected Macaca mulatta
    Migasena P, Maegraith BG
    Med J Malaya, 1968 Mar;22(3):251.
    PMID: 4234389
    Matched MeSH terms: Serum Albumin, Radio-Iodinated
  4. Fulltext Non-ionizing radiation exposure causing ill-health and alopecia areata
    Isa AR, Noor M
    Med J Malaysia, 1991 Sep;46(3):235-8.
    PMID: 1839918
    Three cases of occupational exposure to radio-frequency and microwave radiation were seen at the out-patient clinic, Hospital Universiti Sains Malaysia. They presented with run-down symptoms of neck strain associated with throbbing headache, irritability, loss of appetite, fatigue, memory difficulties, and numbness of extremities. They also presented with alopecia areata which is felt to be causally linked to the radiation exposure.

    Study site: Outpatient clinic Hospital Universiti Sains Malaysia (HUSM)
    Matched MeSH terms: Radio Waves/adverse effects*
  5. Kesan Medan Magnet Menegak ke atas Lengkung Sut Olakan Benard-Marangoni Mantap dalam Lapisan Mengufuk Bendalir (The Effect of a Vertical Magnetic Field on the Onset of Study Bernard-Marangoni Convection in a Horizontal Layer of Electrically Conducting Fluid)
    Ruwaidiah Idris, Ishak Hashim
    Sains Malaysiana, 2005;34.
    In this work we use an analytical technique to analyse the effect of a vertical uniform magnetic field on the onset of steady Benard-Marangoni convection in a horizontal layer of electrically conducting fluid subject to a uniform vertical temperature gradient in the asymptotic limit short waves. We found that in the limit of short waves, the leading order expression for the marginal curve is not affected by the magnetic field.
    Dalam makalah ini kesan medan magnet menegak seragam ke atas lengkung sut permulaan olakan mantap Benard-Marangoni dalam lapisan bendalir mengufuk berpengalir elektrik dikaji tertakluk kepada kecerunan suhu yang seragam dalam had asimptot gelombang pendek. Kami dapati medan magnet tidak memberi kesan kepada sebutan utama lengkung sut dalam had gelombang pendek.
    Matched MeSH terms: Radio Waves
  6. Assessment of radiofrequency/microwave radiation emitted by the antennas of rooftop-mounted mobile phone base stations
    Keow MA, Radiman S
    Radiat Prot Dosimetry, 2006;121(2):122-7.
    PMID: 16357026
    Radiofrequency (RF) and microwave (MW) radiation exposures from the antennas of rooftop-mounted mobile telephone base stations have become a serious issue in recent years due to the rapidly evolving technologies in wireless telecommunication systems. In Malaysia, thousands of mobile telephone base stations have been erected all over the country, most of which are mounted on the rooftops. In view of public concerns, measurements of the RF/MW levels emitted by the base stations were carried out in this study. The values were compared with the exposure limits set by several organisations and countries. Measurements were performed at 200 sites around 47 mobile phone base stations. It was found that the RF/MW radiation from these base stations were well below the maximum exposure limits set by various agencies.
    Matched MeSH terms: Radio Waves/adverse effects*
  7. A low cost solution for post-biopsy complications using available RFA generator and coaxial core biopsy needle
    Azlan CA, Mohd Nasir NF, Saifizul AA, Faizul MS, Ng KH, Abdullah BJ
    Australas Phys Eng Sci Med, 2007 Dec;30(4):288-91.
    PMID: 18274069
    Percutaneous image-guided needle biopsy is typically performed in highly vascular organs or in tumours with rich macroscopic and microscopic blood supply. The main risks related to this procedure are haemorrhage and implantation of tumour cells in the needle tract after the biopsy needle is withdrawn. From numerous conducted studies, it was found that heating the needle tract using alternating current in radiofrequency (RF) range has a potential to minimize these effects. However, this solution requires the use of specially designed needles, which would make the procedure relatively expensive and complicated. Thus, we propose a simple solution by using readily available coaxial core biopsy needles connected to a radiofrequency ablation (RFA) generator. In order to do so, we have designed and developed an adapter to interface between these two devices. For evaluation purpose, we used a bovine liver as a sample tissue. The experimental procedure was done to study the effect of different parameter settings on the size of coagulation necrosis caused by the RF current heating on the subject. The delivery of the RF energy was varied by changing the values for delivered power, power delivery duration, and insertion depth. The results showed that the size of the coagulation necrosis is affected by all of the parameters tested. In general, the size of the region is enlarged with higher delivery of RF power, longer duration of power delivery, and shallower needle insertion and become relatively constant after a certain value. We also found that the solution proposed provides a low cost and practical way to minimizes unwanted post-biopsy effects.
    Matched MeSH terms: Radio Waves/therapeutic use*
  8. Radio frequency electromagnetic radiation (RF-EMR) from GSM (0.9/1.8GHz) mobile phones induces oxidative stress and reduces sperm motility in rats
    Mailankot M, Kunnath AP, Jayalekshmi H, Koduru B, Valsalan R
    Clinics (Sao Paulo), 2009;64(6):561-5.
    PMID: 19578660
    INTRODUCTION: Mobile phones have become indispensable in the daily lives of men and women around the globe. As cell phone use has become more widespread, concerns have mounted regarding the potentially harmful effects of RF-EMR from these devices.

    OBJECTIVE: The present study was designed to evaluate the effects of RF-EMR from mobile phones on free radical metabolism and sperm quality.

    MATERIALS AND METHODS: Male albino Wistar rats (10-12 weeks old) were exposed to RF-EMR from an active GSM (0.9/1.8 GHz) mobile phone for 1 hour continuously per day for 28 days. Controls were exposed to a mobile phone without a battery for the same period. The phone was kept in a cage with a wooden bottom in order to address concerns that the effects of exposure to the phone could be due to heat emitted by the phone rather than to RF-EMR alone. Animals were sacrificed 24 hours after the last exposure and tissues of interest were harvested.

    RESULTS: One hour of exposure to the phone did not significantly change facial temperature in either group of rats. No significant difference was observed in total sperm count between controls and RF-EMR exposed groups. However, rats exposed to RF-EMR exhibited a significantly reduced percentage of motile sperm. Moreover, RF-EMR exposure resulted in a significant increase in lipid peroxidation and low GSH content in the testis and epididymis.

    CONCLUSION: Given the results of the present study, we speculate that RF-EMR from mobile phones negatively affects semen quality and may impair male fertility.

    Matched MeSH terms: Radio Waves/adverse effects*
  9. Fulltext Submandibular intraductal calculi removal as an office procedure with radiofrequency device
    Revadi G, Rahmat O, Shailendra S
    Med J Malaysia, 2010 Mar;65(1):80-2.
    PMID: 21265259 MyJurnal
    Salivary duct obstruction secondary to calculi is a common disorder of the submandibular gland and often manifesting as painful episodic swelling of the gland during meals. Complications may arise in unresolved obstruction leading to infections, abscess formation and a hypofunctioning gland. Treatment of this disorder has evolved from the traditional sialadenectomy to organ preserving procedures done under general or local anaesthesia. Our technique using Ellman Surgitron radiofrequency device, is another alternative technique for transoral removal of extraglandular calculi. It is a simple, quick an easy technique to learn that can be done in the office setting under local anaesthesia.
    Matched MeSH terms: Radio Waves/therapeutic use*
  10. Fulltext Effect of radio-frequency electromagnetic radiations (RF-EMR) on passive avoidance behaviour and hippocampal morphology in Wistar rats
    Narayanan SN, Kumar RS, Potu BK, Nayak S, Bhat PG, Mailankot M
    Ups. J. Med. Sci., 2010 May;115(2):91-6.
    PMID: 20095879 DOI: 10.3109/03009730903552661
    The interaction of mobile phone radio-frequency electromagnetic radiation (RF-EMR) with the brain is a serious concern of our society.
    Matched MeSH terms: Radio Waves*
  11. Radio Frequency Identification (RFID) and communication technologies for solid waste bin and truck monitoring system
    Hannan MA, Arebey M, Begum RA, Basri H
    Waste Manag, 2011 Dec;31(12):2406-13.
    PMID: 21871788 DOI: 10.1016/j.wasman.2011.07.022
    This paper deals with a system of integration of Radio Frequency Identification (RFID) and communication technologies for solid waste bin and truck monitoring system. RFID, GPS, GPRS and GIS along with camera technologies have been integrated and developed the bin and truck intelligent monitoring system. A new kind of integrated theoretical framework, hardware architecture and interface algorithm has been introduced between the technologies for the successful implementation of the proposed system. In this system, bin and truck database have been developed such a way that the information of bin and truck ID, date and time of waste collection, bin status, amount of waste and bin and truck GPS coordinates etc. are complied and stored for monitoring and management activities. The results showed that the real-time image processing, histogram analysis, waste estimation and other bin information have been displayed in the GUI of the monitoring system. The real-time test and experimental results showed that the performance of the developed system was stable and satisfied the monitoring system with high practicability and validity.
    Matched MeSH terms: Radio Frequency Identification Device/methods*
  12. Fulltext An approach for removing redundant data from RFID data streams
    Mahdin H, Abawajy J
    Sensors (Basel), 2011;11(10):9863-77.
    PMID: 22163730 DOI: 10.3390/s111009863
    Radio frequency identification (RFID) systems are emerging as the primary object identification mechanism, especially in supply chain management. However, RFID naturally generates a large amount of duplicate readings. Removing these duplicates from the RFID data stream is paramount as it does not contribute new information to the system and wastes system resources. Existing approaches to deal with this problem cannot fulfill the real time demands to process the massive RFID data stream. We propose a data filtering approach that efficiently detects and removes duplicate readings from RFID data streams. Experimental results show that the proposed approach offers a significant improvement as compared to the existing approaches.
    Matched MeSH terms: Radio Frequency Identification Device/methods*
  13. Thermocatalytic treatment of biomass tar model compounds via radio frequency
    Anis S, Zainal ZA, Bakar MZ
    Bioresour Technol, 2013 May;136:117-25.
    PMID: 23567671 DOI: 10.1016/j.biortech.2013.02.049
    A new effective RF tar thermocatalytic treatment process with low energy intensive has been proposed to remove tar from biomass gasification. Toluene and naphthalene as biomass tar model compounds were removed via both thermal and catalytic treatment over a wide temperature range from 850 °C to 1200 °C and 450 °C to 900 °C, respectively at residence time of 0-0.7 s. Thermal characteristics of the new technique are also described in this paper. This study clearly clarified that toluene was much easier to be removed than naphthalene. Soot was found as the final product of thermal treatment of the tar model and completely removed during catalytic treatment. Radical reactions generated by RF non-thermal effect improve the tar removal. The study showed that Y-zeolite has better catalytic activity compared to dolomite on toluene and naphthalene removal due to its acidic nature and large surface area, even at lower reaction temperature of about 550 °C.
    Matched MeSH terms: Radio Waves*
  14. Fulltext A New Metasurface Superstrate Structure for Antenna Performance Enhancement
    Islam MT, Ullah MH, Singh MJ, Faruque MRI
    Materials (Basel), 2013 Jul 31;6(8):3226-3240.
    PMID: 28811432 DOI: 10.3390/ma6083226
    A new metasurface superstrate structure (MSS)-loaded dual band microstrip line-fed small patch antenna is presented in this paper. The proposed antenna was designed on a ceramic-filled bioplastic sandwich substrate with a high dielectric constant. The proposed 7 × 6 element, square-shaped, single-sided MSS significantly improved the bandwidth and gain of the proposed antenna. The proposed MSS incorporated a slotted patch antenna that effectively increased the measured operating bandwidth from 13.3% to 18.8% and from 14.8% to 23.2% in the lower and upper bands, respectively. Moreover, the average gain of the proposed MSS-based antenna was enhanced from 2.12 dBi to 3.02 dBi in the lower band and from 4.10 dBi to 5.28 dBi in the upper band compared to the patch antenna alone. In addition to the bandwidth and gain improvements, more directive radiation characteristics were also observed from the MSS antenna compared to the patch itself. The effects of the MSS elements and the ground plane length on the reflection coefficient of the antenna were analyzed and optimized. The overall performance makes the proposed antenna appropriate for RFID and WLAN applications.
    Matched MeSH terms: Radio Frequency Identification Device
  15. Upgrading producer gas quality from rubber wood gasification in a radio frequency tar thermocatalytic treatment reactor
    Anis S, Zainal ZA
    Bioresour Technol, 2013 Dec;150:328-37.
    PMID: 24185417 DOI: 10.1016/j.biortech.2013.10.010
    This study focused on improving the producer gas quality using radio frequency (RF) tar thermocatalytic treatment reactor. The producer gas containing tar, particles and water was directly passed at a particular flow rate into the RF reactor at various temperatures for catalytic and thermal treatments. Thermal treatment generates higher heating value of 5.76 MJ Nm(-3) at 1200°C. Catalytic treatments using both dolomite and Y-zeolite provide high tar and particles conversion efficiencies of about 97% on average. The result also showed that light poly-aromatic hydrocarbons especially naphthalene and aromatic compounds particularly benzene and toluene were still found even at higher reaction temperatures. Low energy intensive RF tar thermocatalytic treatment was found to be effective for upgrading the producer gas quality to meet the end user requirements and increasing its energy content.
    Matched MeSH terms: Radio Waves*
  16. Effects of the nitric acid concentrations on the etching process, structural and optical properties of porous zinc oxide thin films
    C.G. Ching, Leonard Lu, C.I. Ang, P.K. Ooi, S.S. Ng, Z. Hassan, et al.
    Sains Malaysiana, 2013;42:1327-1332.
    The present study reports on the fabrication of porous zinc oxide by wet chemical etching. ZnO thin films were deposited via radio-frequency magnetron sputtering on p-type silicon with (111) preferred orientation. The etchants used in the present work were 0.1% and 1.0% nitric acid (HNO3) solutions. ZnO were etched at various times and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectroscopy to allow the examination of their structural and optical properties. The XRD results revealed that the intensity of ZnO(002) decreased when the thin films were etched in varying HNO3 concentrations over different periods of time. The above observation is attributed to the dissolution of the ZnO(002). The SEM images showed that the thickness of the ZnO layers decreased over the etching time, which resulted from the isotropic etching by the HNO3 solution. The PL emission intensity initially increased with increasing etching time. However, with further etching of the samples, the PL spectra showed a decreasing trend in intensity as a result of the decrease in the surface-to-volume ratio. All results lead to the conclusion that 1.0% HNO3 has the capability to change the ZnO surface significantly.
    Matched MeSH terms: Radio Waves
  17. Fulltext Wireless displacement sensing of micromachined spiral-coil actuator using resonant frequency tracking
    Ali MS, AbuZaiter A, Schlosser C, Bycraft B, Takahata K
    Sensors (Basel), 2014 Jul 10;14(7):12399-409.
    PMID: 25014100 DOI: 10.3390/s140712399
    This paper reports a method that enables real-time displacement monitoring and control of micromachined resonant-type actuators using wireless radiofrequency (RF). The method is applied to an out-of-plane, spiral-coil microactuator based on shape-memory-alloy (SMA). The SMA spiral coil forms an inductor-capacitor resonant circuit that is excited using external RF magnetic fields to thermally actuate the coil. The actuation causes a shift in the circuit's resonance as the coil is displaced vertically, which is wirelessly monitored through an external antenna to track the displacements. Controlled actuation and displacement monitoring using the developed method is demonstrated with the microfabricated device. The device exhibits a frequency sensitivity to displacement of 10 kHz/µm or more for a full out-of-plane travel range of 466 µm and an average actuation velocity of up to 155 µm/s. The method described permits the actuator to have a self-sensing function that is passively operated, thereby eliminating the need for separate sensors and batteries on the device, thus realizing precise control while attaining a high level of miniaturization in the device.
    Matched MeSH terms: Radio Waves
  18. Fulltext A survey of middleware for sensor and network virtualization
    Khalid Z, Fisal N, Rozaini M
    Sensors (Basel), 2014;14(12):24046-97.
    PMID: 25615737 DOI: 10.3390/s141224046
    Wireless Sensor Network (WSN) is leading to a new paradigm of Internet of Everything (IoE). WSNs have a wide range of applications but are usually deployed in a particular application. However, the future of WSNs lies in the aggregation and allocation of resources, serving diverse applications. WSN virtualization by the middleware is an emerging concept that enables aggregation of multiple independent heterogeneous devices, networks, radios and software platforms; and enhancing application development. WSN virtualization, middleware can further be categorized into sensor virtualization and network virtualization. Middleware for WSN virtualization poses several challenges like efficient decoupling of networks, devices and software. In this paper efforts have been put forward to bring an overview of the previous and current middleware designs for WSN virtualization, the design goals, software architectures, abstracted services, testbeds and programming techniques. Furthermore, the paper also presents the proposed model, challenges and future opportunities for further research in the middleware designs for WSN virtualization.
    Matched MeSH terms: Radio
  19. Fulltext Automatic frequency controller for power amplifiers used in bio-implanted applications: issues and challenges
    Hannan MA, Hussein HA, Mutashar S, Samad SA, Hussain A
    Sensors (Basel), 2014;14(12):23843-70.
    PMID: 25615728 DOI: 10.3390/s141223843
    With the development of communication technologies, the use of wireless systems in biomedical implanted devices has become very useful. Bio-implantable devices are electronic devices which are used for treatment and monitoring brain implants, pacemakers, cochlear implants, retinal implants and so on. The inductive coupling link is used to transmit power and data between the primary and secondary sides of the biomedical implanted system, in which efficient power amplifier is very much needed to ensure the best data transmission rates and low power losses. However, the efficiency of the implanted devices depends on the circuit design, controller, load variation, changes of radio frequency coil's mutual displacement and coupling coefficients. This paper provides a comprehensive survey on various power amplifier classes and their characteristics, efficiency and controller techniques that have been used in bio-implants. The automatic frequency controller used in biomedical implants such as gate drive switching control, closed loop power control, voltage controlled oscillator, capacitor control and microcontroller frequency control have been explained. Most of these techniques keep the resonance frequency stable in transcutaneous power transfer between the external coil and the coil implanted inside the body. Detailed information including carrier frequency, power efficiency, coils displacement, power consumption, supplied voltage and CMOS chip for the controllers techniques are investigated and summarized in the provided tables. From the rigorous review, it is observed that the existing automatic frequency controller technologies are more or less can capable of performing well in the implant devices; however, the systems are still not up to the mark. Accordingly, current challenges and problems of the typical automatic frequency controller techniques for power amplifiers are illustrated, with a brief suggestions and discussion section concerning the progress of implanted device research in the future. This review will hopefully lead to increasing efforts towards the development of low powered, highly efficient, high data rate and reliable automatic frequency controllers for implanted devices.
    Matched MeSH terms: Radio Waves
  20. Fulltext Design and optimization of LTE 1800 MIMO antenna
    Wong HS, Islam MT, Kibria S
    ScientificWorldJournal, 2014;2014:725806.
    PMID: 24967440 DOI: 10.1155/2014/725806
    A multiple input and multiple output (MIMO) antenna that comprises a printed microstrip antenna and a printed double-L sleeve monopole antenna for LTE 1800 wireless application is presented. The printed double-L sleeve monopole antenna is fed by a 50 ohm coplanar waveguide (CPW). A novel T-shaped microstrip feedline printed on the other side of the PCB is used to excite the waveguide's outer shell. Isolation characteristics better than -15 dB can be obtained for the proposed MIMO antenna. The proposed antenna can operate in LTE 1800 (1710 MHz-1880 MHz). This antenna exhibits omnidirectional characteristics. The efficiency of the antenna is greater than 70% and has high gain of 2.18 dBi.
    Matched MeSH terms: Radio/instrumentation*
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