Displaying publications 481 - 500 of 712 in total

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  1. Adibah Yusof NA, Abdul Karim MK, Asikin NM, Paiman S, Awang Kechik MM, Abdul Rahman MA, et al.
    Curr Med Imaging, 2023;19(10):1105-1113.
    PMID: 35975862 DOI: 10.2174/1573405618666220816160544
    BACKGROUND: For almost three decades, computed tomography (CT) has been extensively used in medical diagnosis, which led researchers to conduct linking of CT dose exposure with image quality.

    METHODS: In this study, a systematic review and a meta-analysis study were conducted on CT phantom for resolution study especially based on the low contrast detectability (LCD). Furthermore, the association between the CT parameter such as tube voltage and the type of reconstruction algorithm, the amount of phantom scanning affecting the image quality and the exposure dose were also investigated in this study. We utilize PubMed, ScienceDirect, Google Scholar and Scopus databases to search related published articles from the year 2011 until 2020. The notable keywords comprise "computed tomography", "CT phantom", and "low contrast detectability". Of 52 articles, 20 articles are within the inclusion criteria in this systematic review.

    RESULTS: The dichotomous outcomes were chosen to represent the results in terms of risk ratio as per meta-analysis study. Notably, the noise in iterative reconstruction (IR) reduced by 24%, 33% and 36% with the use of smooth, medium and sharp filters, respectively. Furthermore, adaptive iterative dose reduction (AIDR 3D) improved image quality and the visibility of smaller less dense objects compared to filtered back-projection. Most of the researchers used 120 kVp tube voltage to scan phantom for quality assurance study.

    CONCLUSION: Hence, optimizing primary factors such as tube potential reduces the dose exposure significantly, and the optimized IR technique could substantially reduce the radiation dose while maintaining the image quality.

    Matched MeSH terms: Radiation Dosage
  2. Sulieman A, Mahgoub O, Salah H, Tamam N, Taha A, Dawood S, et al.
    Appl Radiat Isot, 2023 Dec;202:111071.
    PMID: 37871398 DOI: 10.1016/j.apradiso.2023.111071
    Due to the extended localized fluoroscopy, many radiographic exposures, and multiple procedures that might result in tissue reaction, patients and personnel received a significant radiation dose during interventional cardiology (IR) procedures. This study aims to calculate the radiation risk and assess patient and staff effective doses during IC procedures. Thirty-two patients underwent a Cath lab treatment in total. Ten Cath lab personnel, including six nurses, two cardiologists, and two X-ray technologists. Optical stimulating-luminescent dosimeters (OSL) (Al2O3:C) calibrated for this purpose were used to monitor both occupational and ambient doses. Using an automated OSL reader, these badges were scanned. The Air Kerma (mGy) and Kerma Area Products (KAP, mGy.cm2) have a mean and standard deviation (SD) of 371 ± 132 and 26052, respectively. The average personal dose equivalent (mSv) and its range for cardiologists, nurses and X ray technologists were 1.11 ± 0.21 (0.96-1.26), 0.84 ± 0.11 (0.68-1.16), and 0.68 ± 0.014 (0.12-0.13), respectively. The current study findings showed that the annual effective dose for cardiologists, nurses, and X-ray technologists was lesser than the yearly occupational dose limit of 20 mSv recommended by national and international guidelines. The patients' doses are comparable with some previously published studies and below the tissue reaction limits.
    Matched MeSH terms: Radiation Dosage
  3. Ahmed Shaker Hegian Z, Moh'd Abu Tahoun L, Ramli RM, Noor Azman NZ
    Radiat Prot Dosimetry, 2023 Dec 29;200(1):25-31.
    PMID: 37738470 DOI: 10.1093/rpd/ncad259
    The mean glandular dose (MGD) is a measurement used in mammography to assess the amount of radiation absorbed. By considering specific exposure radiation dose criteria, MGD ensures minimal radiation while maintaining image quality for detecting abnormalities. The relationship between MGD and compressed breast thickness (CBT) is commonly utilized in mammographic dose surveys. This study aims to estimate the MGD-CBT relationship based on patient age in Jordan through retrospective analysis. The analysis involved 3465 screening mammography images of women aged 40-80, divided into three age groups: 40-49, 50-64 and 65-80 years. Each group had a specific CBT range (16.5-156 mm). The results indicate that MGD ranges from 1.6 to 1.7 mGy across all three age groups, independent of CBT. Thus, a significant and positive correlation exists between MGD and CBT in all age groups.
    Matched MeSH terms: Radiation Dosage
  4. Pradhoshini KP, Santhanabharathi B, Priyadharshini M, Ahmed MS, Murugan K, Sivaperumal P, et al.
    Environ Res, 2024 Mar 01;244:118000.
    PMID: 38128601 DOI: 10.1016/j.envres.2023.118000
    The present investigation is the first of its kind which aims to study the characteristics of microbial consortium inhabiting one of the natural high background radiation areas of the world, Chavara Coast in Kerala, India. The composition of the microbial community and their structural changes were evaluated under the natural circumstances with exorbitant presence of radionuclides in the sediments and after the radionuclide's recession due to mining effects. For this purpose, the concentration of radionuclides, heavy metals, net radioactivity estimation via gross alpha and beta emitters and other physiochemical characteristics were assessed in the sediments throughout the estuarine stretch. According to the results, the radionuclides had a significant effect in shaping the community structure and composition, as confirmed by the bacterial heterogeneity achieved between the samples. The results indicate that high radioactivity in the background environment reduced the abundance and growth of normal microbial fauna and favoured only the growth of certain extremophiles belonging to families of Piscirickettsiacea, Rhodobacteriacea and Thermodesulfovibrionaceae, which were able to tolerate and adapt towards the ionizing radiation present in the environment. In contrast, communities from Comamondacea, Sphingomonadacea, Moraxellacea and Erythrobacteracea were present in the sediments collected from industrial outlet, reinforcing the potent role of radionuclides in governing the community pattern of microbes present in the natural environment. The study confirms the presence of these novel and unidentified bacterial communities and further opens the possibility of utilizing their usefulness in future prospects.
    Matched MeSH terms: Background Radiation
  5. Abdullah KA, McEntee MF, Reed W, Kench PL
    J Med Imaging Radiat Oncol, 2016 Aug;60(4):459-68.
    PMID: 27241506 DOI: 10.1111/1754-9485.12473
    The aim of this systematic review is to evaluate the radiation dose reduction achieved using iterative reconstruction (IR) compared to filtered back projection (FBP) in coronary CT angiography (CCTA) and assess the impact on diagnostic image quality. A systematic search of seven electronic databases was performed to identify all studies using a developed keywords strategy. A total of 14 studies met the criteria and were included in a review analysis. The results showed that there was a significant reduction in radiation dose when using IR compared to FBP (P  0.05). The mean ± SD difference of image noise, signal-noise ratio (SNR) and contrast-noise ratio (CNR) were 1.05 ± 1.29 HU, 0.88 ± 0.56 and 0.63 ± 1.83 respectively. The mean ± SD percentages of overall image quality scores were 71.79 ± 12.29% (FBP) and 67.31 ± 22.96% (IR). The mean ± SD percentages of coronary segment analysis were 95.43 ± 2.57% (FBP) and 97.19 ± 2.62% (IR). In conclusion, this review analysis shows that CCTA with the use of IR leads to a significant reduction in radiation dose as compared to the use of FBP. Diagnostic image quality of IR at reduced dose (30-41%) is comparable to FBP at standard dose in the diagnosis of CAD.
    Matched MeSH terms: Radiation Dosage*
  6. Jothy SL, Chen Y, Vijayarathna S, Kanwar JR, Sasidharan S
    Curr Gene Ther, 2015;15(1):15-20.
    PMID: 25478696
    Radiotherapy plays an essential primary role in cancer patients. Regardless of its significant advances in treatment options, tumor recurrence and radio-resistance in cancer cells still occur in a high percentage of patients. Furthermore, the over expression of miRNAs accompanies the development of radio-resistant cancer cells. Consequently, miRNAs might serve as therapeutic targets for the treatment of radio-resistance in cancer cells. The findings of the current research also signify that the use of a natural anti-miRNA substance could inhibit specific miRNAs, and, concurrently, these natural remedies could exhibit radioprotective activity against the healthy cells during radiotherapy. Therefore, in this review, we have reported the association of miRNAs with radio-resistance and the potential uses of natural remedies as green gene therapeutic approaches, as well as radioprotectors against the adverse effects of irradiation on healthy cells during radiotherapy.
    Matched MeSH terms: Radiation-Protective Agents/pharmacology
  7. Liew KH, Loh PL, Juan JC, Yarmo MA, Yusop RM
    ScientificWorldJournal, 2014;2014:796196.
    PMID: 25054185 DOI: 10.1155/2014/796196
    Cross-linked resin-captured palladium (XL-QPPd) was readily prepared by simple physical adsorption onto the high loading QuadraPure macroporous resin and a subsequent reduction process. To enhance the mechanical stability, entrapped palladium nanocatalysts were cross-linked with succinyl chloride. Both transmission electron microscopy images and X-ray diffraction analysis revealed that the palladium nanoparticles were well dispersed with diameters ranging in 4-10 nm. The catalyst performed good catalytic activity in microwave-promoted Suzuki cross-coupling reactions in water under aerobic condition with mild condition by using various aryl halides and phenylboronic acid. In addition, the catalyst showed an excellent recyclability without significant loss of catalytic activity.
    Matched MeSH terms: Resins, Synthetic/radiation effects
  8. Imaizumi Y, Nagao N, Yusoff FM, Taguchi S, Toda T
    Bioresour Technol, 2014 Jun;162:53-9.
    PMID: 24747382 DOI: 10.1016/j.biortech.2014.03.123
    To determine the optimum light intensity per cell required for rapid growth regardless of cell density, continuous cultures of the microalga Chlorella zofingiensis were grown with a sufficient supply of nutrients and CO2 and were subjected to different light intensities in the range of 75-1000 μE m(-2) s(-1). The cell density of culture increased over time for all light conditions except for the early stage of the high light condition of 1000 μE m(-2) s(-1). The light intensity per cell required for the high specific growth rate of 0.5 day(-1) was determined to be 28-45 μE g-ds(-1) s(-1). The specific growth rate was significantly correlated to light intensity (y=0.721×x/(66.98+x), r(2)=0.85, p<0.05). A high specific growth rate was maintained over a range of light intensities (250-1000 μE m(-2) s(-1)). This range of light intensities suggested that effective production of C. zofingiensis can be maintained outdoors under strong light by using the optimum specific light intensity.
    Matched MeSH terms: Chlorella/radiation effects*
  9. Teo CL, Atta M, Bukhari A, Taisir M, Yusuf AM, Idris A
    Bioresour Technol, 2014 Jun;162:38-44.
    PMID: 24736210 DOI: 10.1016/j.biortech.2014.03.113
    Wavelength of light is a crucial factor which renders microalgae as the potential biodiesel. In this study, Tetraselmis sp. and Nannochloropsis sp. as famous targets were selected. The effect of different light wavelengths on growth rate and lipid production was studied. Microalgae were cultivated for 14 days as under blue, red, red-blue LED and white fluorescent light. The growth rate of microalgae was analyzed by spectrophotometer and cell counting while oil production under improved Nile red method. Optical density result showed the microalgae exhibited better growth curve under blue wavelength. Besides, Tetraselmis sp. and Nannochloropsis sp. under blue wavelength showed the higher growth rate (1.47 and 1.64 day(-1)) and oil production (102.954 and 702.366 a.u.). Gas chromatography analysis also showed that palmitic acid and stearic acid which were compulsory components for biodiesel contribute around 49-51% of total FAME from Nannochloropsis sp. and 81-83% of total FAME from Tetraselmis sp.
    Matched MeSH terms: Microalgae/radiation effects
  10. Amjad RJ, Sahar MR, Dousti MR, Ghoshal SK, Jamaludin MN
    Opt Express, 2013 Jun 17;21(12):14282-90.
    PMID: 23787617 DOI: 10.1364/OE.21.014282
    We report significant enhancements in Er(3+) luminescence as well as in Raman intensity in silver nanoparticles embedded zinc-tellurite glass. Surface enhanced Raman scattering effect is highlighted for the first time in tellurite glass containing silver NPs resulting in an enhanced Raman signal (~10 times). SAED manifest the growth of Ag(0) nanoparticles along the (111) and (200) crystallographic planes having average diameter in the range 14-36 nm. Surface plasmon resonance bands are observed in the range 484-551 nm. Furthermore, four prominent photoluminescence bands undergo significant enhancements up to 3 times. The enhancement is majorly attributed to the local field effect of silver NPs.
    Matched MeSH terms: Silver/radiation effects
  11. Jalil MA, Phelawan J, Aziz MS, Saktioto T, Ong CT, Yupapin PP
    Artif Cells Nanomed Biotechnol, 2013 Apr;41(2):92-7.
    PMID: 22991968 DOI: 10.3109/10731199.2012.700519
    Acne vulgaris is adebilitating dermatologic disease, and is conventionally treated by laser therapy using a microring resonator system. An evolving understanding of laser-tissue interactions involving Propioni bacterium acneproducing porphyrins, and the development of lasers to target the sebaceous glands, has led to the development of an escalating number of laser light for acne treatment. The results show that the full width at half maximum of the proposed laser pulse of 0.15 nm can be generated using a microring resonator system. The power of the laser is 200 W and the wavelength laser is 1,032 nm, which is proposed as a treatment of acne vulgaris diseases.
    Matched MeSH terms: Sebaceous Glands/radiation effects*
  12. Abdollahi Y, Abdullah AH, Zainal Z, Yusof NA
    Int J Mol Sci, 2012;13(1):302-15.
    PMID: 22312253 DOI: 10.3390/ijms13010302
    Photocatalytic degradation of p-cresol was carried out using ZnO under UV irradiation. The amount of photocatalyst, concentration of p-cresol and pH were studied as variables. The residual concentration and mineralization of p-cresol was monitored using a UV-visible spectrophotometer and total organic carbon (TOC) analyzer, respectively. The intermediates were detected by ultra high pressure liquid chromatography (UPLC). The highest photodegradation of p-cresol was observed at 2.5 g/L of ZnO and 100 ppm of p-cresol. P-cresol photocatalytic degradation was favorable in the pH range of 6-9. The detected intermediates were 4-hydroxy-benzaldehyde and 4-methyl-1,2-benzodiol. TOC studies show that 93% of total organic carbon was removed from solution during irradiation time. Reusability shows no significant reduction in photocatalytic performance in photodegrading p-cresol.
    Matched MeSH terms: Photolysis/radiation effects
  13. Salehi Z, Yusoff AL
    Radiat Prot Dosimetry, 2013;154(3):396-9.
    PMID: 23012482 DOI: 10.1093/rpd/ncs239
    A femur phantom made of wax and a real human bone was used to study the dose during radiographical procedures. The depth dose inside the phantom was determined using DOSXYZnrc, a Monte Carlo simulation software. The results were verified with measurements using TLD-100H. It was found that for 2.5 mm aluminium filtered 84-kVp X-rays, the radiation dose in the bone reached 57 % higher than the surface dose, i.e. 3.23 mGy as opposed to 2.06 mGy at the surface. The use of real bone introduces variations in the bone density in the DOSXYZnrc model, resulting in a lower attenuation effect than expected from solid bone tissues.
    Matched MeSH terms: Radiation Dosage*
  14. H M, Khatib A, Shaari K, Abas F, Shitan M, Kneer R, et al.
    J Agric Food Chem, 2012 Jan 11;60(1):410-7.
    PMID: 22084897 DOI: 10.1021/jf200270y
    The metabolites of three species of Apiaceae, also known as Pegaga, were analyzed utilizing (1)H NMR spectroscopy and multivariate data analysis. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) resolved the species, Centella asiatica, Hydrocotyle bonariensis, and Hydrocotyle sibthorpioides, into three clusters. The saponins, asiaticoside and madecassoside, along with chlorogenic acids were the metabolites that contributed most to the separation. Furthermore, the effects of growth-lighting condition to metabolite contents were also investigated. The extracts of C. asiatica grown in full-day light exposure exhibited a stronger radical scavenging activity and contained more triterpenes (asiaticoside and madecassoside), flavonoids, and chlorogenic acids as compared to plants grown in 50% shade. This study established the potential of using a combination of (1)H NMR spectroscopy and multivariate data analyses in differentiating three closely related species and the effects of growth lighting, based on their metabolite contents and identification of the markers contributing to their differences.
    Matched MeSH terms: Centella/radiation effects
  15. Muhammad BG, Jaafar MS, Azhar AR, Akpa TC
    Radiat Prot Dosimetry, 2012 Apr;149(3):340-6.
    PMID: 21642647 DOI: 10.1093/rpd/ncr230
    Measurements of (222)Rn activity concentration were carried out in 39 samples collected from the domestic and drinking water sources used in the island and mainland of Penang, northern peninsular, Malaysia. The measured activity concentrations ranged from 7.49 to 26.25 Bq l(-1), 0.49 to 9.72 Bq l(-1) and 0.58 to 2.54 Bq l(-1) in the raw, treated and bottled water samples collected, respectively. This indicated relatively high radon concentrations compared with that from other parts of the world, which still falls below the WHO recommended treatment level of 100 Bq l(-1). From this data, the age-dependent associated committed effective doses due to the ingestion of (222)Rn as a consequence of direct consumption of drinking water were calculated. The committed effective doses from (222)Rn resulting from 1 y's consumption of these water were estimated to range from 0.003 to 0.048, 0.001 to 0.018 and 0.002 to 0.023 mSv y(-1), for age groups 0-1, 2-16 and >16 y, respectively.
    Matched MeSH terms: Radiation Dosage; Radiation Monitoring
  16. Mohd Nasir N, Teo Ming T, Ahmadun FR, Sobri S
    Water Sci Technol, 2010;62(1):42-7.
    PMID: 20595752 DOI: 10.2166/wst.2010.239
    The research conducted a study on decomposition and biodegradability enhancement of textile wastewater using a combination of electron beam irradiation and activated sludge process. The purposes of this research are to remove pollutant through decomposition and to enhance the biodegradability of textile wastewater. The wastewater is treated using electron beam irradiation as a pre-treatment before undergo an activated sludge process. As a result, for non-irradiated wastewater, the COD removal was achieved to be between 70% and 79% after activated sludge process. The improvement of COD removal efficiency increased to 94% after irradiation of treated effluent at the dose of 50 kGy. Meanwhile, the BOD(5) removal efficiencies of non-irradiated and irradiated textile wastewater were reported to be between 80 and 87%, and 82 and 99.2%, respectively. The maximum BOD(5) removal efficiency was achieved at day 1 (HRT 5 days) of the process of an irradiated textile wastewater which is 99.2%. The biodegradability ratio of non-irradiated wastewater was reported to be between 0.34 and 0.61, while the value of biodegradability ratio of an irradiated wastewater increased to be between 0.87 and 0.96. The biodegradability enhancement of textile wastewater is increased with increasing the doses. Therefore, an electron beam radiation holds a greatest application of removing pollutants and also on enhancing the biodegradability of textile wastewater.
    Matched MeSH terms: Radiation*
  17. Kuan YH, Bhat R, Senan C, Williams PA, Karim AA
    J Agric Food Chem, 2009 Oct 14;57(19):9154-9.
    PMID: 19757813 DOI: 10.1021/jf9015625
    The impact of ultraviolet (UV) irradiation on the physicochemical and functional properties of gum arabic was investigated. Gum arabic samples were exposed to UV irradiation for 30, 60, 90, and 120 min; gum arabic was also treated with formaldehyde for comparison. Molecular weight analysis using gel permeation chromatography indicated that no significant changes occurred on the molecular structure on the samples exposed to UV irradiation. Free amino group analysis indicated that mild UV irradiation (30 min) could induce cross-linking on gum arabic; this result was comparable with that of samples treated with formaldehyde. However, viscosity break down was observed for samples exposed to UV irradiation for longer times (90 and 120 min). All irradiated and formaldehyde-treated samples exhibited better emulsification properties than unirradiated samples. These results indicate that UV-irradiated gum arabic could be a better emulsifier than the native (unmodified) gum arabic and could be exploited commercially.
    Matched MeSH terms: Gum Arabic/radiation effects*
  18. Ting TM, Jamaludin N
    Chemosphere, 2008 Aug;73(1):76-80.
    PMID: 18571692 DOI: 10.1016/j.chemosphere.2008.05.007
    Dyeing wastewater was known to have strong color and refractory organic pollutants. In this study irradiation alone was used for dyes wastewater treatment. This paper studies the effect of the concentrations of pollutants to its removal at various dosages using electron beam technology. Irradiation was effective in removing the highly colored and refractory organic compounds. The color removal for initial concentrations of 255 CU, 520 CU, 990 CU and 1900 CU treated using irradiation at 0.5 kGy were 61%, 48%, 28% and 16%, respectively. However, at the dose of 108 kGy and higher, the color removal between 87% and 96% were recorded with no apparent trend. COD removal also reported similar trend but at relatively lower removal percentage. The COD removal at 0.5 kGy for initial COD concentrations of 57 mg/l and 515 mg/l were 10% and 0%, respectively. At irradiation dose of 108 kGy, the removal for initial COD concentrations of 57 mg/l and 515 mg/l were 37% and 13%, respectively. This showed that concentrations of pollutants and dose of irradiation applied to remove color and COD were dependent to each other.
    Matched MeSH terms: Water Pollutants, Chemical/radiation effects*
  19. Bahari I, Mohsen N, Abdullah P
    J Environ Radioact, 2007;95(2-3):161-70.
    PMID: 17428589
    The processing of amang, or tin tailings, for valuable minerals has been shown to technologically enhance NORM and this has stirred significant radiological safety and health concerns among Malaysia's regulatory authority. A growing radiological concern is now focused on the amang effluent containing NORM in recycling ponds, since these ponds may be reclaimed for future residential developments. A study was carried out to assess the radiological risk associated with amang processing and the accumulated effluent in the recycling ponds. Twenty-six sediment samples from the recycling ponds of two amang plants in the states of Selangor and Perak, Malaysia, were collected and analyzed. The maximum activity concentrations of (238)U, (226)Ra, (232)Th and (40)K recorded in sediments from these ponds were higher than Malaysia's and the world's natural highest. Correspondingly, the mean radium equivalent activity concentration indices, Ra(eq), and gamma radiation representative level index, I(gammar), were higher than the world's average. The enhancement of NORM in effluent sediments as a consequence of amang processing, and the use of a closed water management recycling system created Effective Dose Rates, E (nSv h(-1)), that signal potential environmental radiological risks in these ponds, should they be reclaimed for future land use.
    Matched MeSH terms: Radiation Dosage; Radiation Monitoring
  20. Sulaiman AR, Nawaz H, Munajat I, Sallehudin AY
    J Orthop Surg (Hong Kong), 2007 Apr;15(1):84-6.
    PMID: 17429125
    We report a case of the Antley-Bixler syndrome in an 11-year-old girl. She presented with bilateral proximal femoral focal deficiency, right clubfoot, left radiohumeral synostosis, bilateral ear hypoplasia, cleft palate, tongue tie, missing teeth, congenital heart disease, a pelvic kidney with hydronephrosis, and mental retardation. Proximal femoral focal deficiency has never been reported before as a manifestation of Antley-Bixler syndrome. Her mother was exposed to radiation during an intravenous urogram done in the first trimester of pregnancy. Exposure to radiation has not been implicated as a cause of Antley-Bixler syndrome.
    Matched MeSH terms: Abnormalities, Radiation-Induced*
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