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Fulltext Symmetric resonator based tunable epsilon negative near zero index metamaterial with high effective medium ratio for multiband wireless applications

Moniruzzaman M, Islam MT, Hossain I, Soliman MS, Samsuzzaman M, Almalki SHA

Sci Rep, 2021 Nov 08;11(1):21842.
PMID: 34750440 DOI: 10.1038/s41598-021-01266-7

In this paper, a tuned metamaterial (MTM) consisting of a symmetric split ring resonator is presented that exhibits epsilon negative (ENG), near zero permeability and refractive index properties for multiband microwave applications. The proposed metamaterial is constituted on a Rogers (RT-5880) substrate with 1.57 mm thickness and the electrical dimension of 0.14λ × 0.14λ, where wavelength, λ is calculated at 4.2 GHz. The symmetric resonating patch is subdivided into four equal and similar quartiles with two interconnecting split rings in each quartile. The quartiles are connected at the center of the substrate with a square metal strip with which four tuning metal strips are attached. These tuning metal strips are acted as spacers between four quartiles of the resonator patch. Numerical simulation of the proposed design is executed in CST microwave studio. The proposed MTM provides four resonances of transmission coefficient (S21) at 4.20 GHz, 10.14 GHz, 13.15 GHz, and 17.1 GHz covering C, X and Ku bands with negative permittivity, near zero permeability and refractive index. The calculated effective medium ratio (EMR) is 7.14 at 4.2 GHz indicates its compactness. The resonance frequencies are selective in nature which can be easily tuned by varying the length of the tuning metal stubs. The equivalent circuit of the proposed MTM is modelled in Advanced Design Software (ADS) that exhibits a similar S21 compared with CST simulation. Surface current, electric and magnetic fields are analyzed to explain the frequency tuning property and other performances of the MTM. Compact size, ENG with near zero permeability and refractive index along with frequency selectivity through tuning provides flexibility for frequency selective applications of this MTM in wireless communications.
Fulltext Intact urothelial barrier function in a mouse model of ketamine-induced voiding dysfunction

Rajandram R, Ong TA, Razack AH, MacIver B, Zeidel M, Yu W

Am J Physiol Renal Physiol, 2016 05 01;310(9):F885-94.
PMID: 26911853 DOI: 10.1152/ajprenal.00483.2015

Ketamine is a popular choice for young drug abusers. Ketamine abuse causes lower urinary tract symptoms, with the underlying pathophysiology poorly understood. Disruption of urothelial barrier function has been hypothesized to be a major mechanism for ketamine cystitis, yet the direct evidence of impaired urothelial barrier function is still lacking. To address this question, 8-wk-old female C57BL/6J mice were injected intraperitoneally with 30 mg·kg(-1)·day(-1) ketamine for 12 wk to induce ketamine cystitis. A spontaneous voiding spot assay showed that ketamine-treated mice had increased primary voiding spot numbers and smaller primary voiding spot sizes than control mice (P < 0.05), indicating a contracted bladder and bladder overactivity. Consistently, significantly increased voiding frequency was observed in ketamine-treated mice on cystometrograms. These functional experiments indicate that ketamine induces voiding dysfunction in mice. Surprisingly, urothelial permeability in ketamine-treated mice was not changed when measured using an Ussing chamber system with isotopic urea and water. Mouse urothelial structure was also not altered, and intact umbrella cell structure was observed by both transmission and scanning electron microscopy. Furthermore, immunostaining and confocal microscopy confirmed the presence of a well-defined distribution of zonula occuldens-1 in tight junctions and uroplakin in umbrella cells. In conclusion, these data indicate that ketamine injection induces voiding dysfunction in mice but does not necessarily disrupt mouse bladder barrier function. Disruption of urothelial barrier function may not be the major mechanism in ketamine cystitis.
Fulltext Multi-population Black Hole Algorithm for the problem of data clustering

Salih SQ, Alsewari AA, Wahab HA, Mohammed MKA, Rashid TA, Das D, et al.

PLoS One, 2023;18(7):e0288044.
PMID: 37406006 DOI: 10.1371/journal.pone.0288044

The retrieval of important information from a dataset requires applying a special data mining technique known as data clustering (DC). DC classifies similar objects into a groups of similar characteristics. Clustering involves grouping the data around k-cluster centres that typically are selected randomly. Recently, the issues behind DC have called for a search for an alternative solution. Recently, a nature-based optimization algorithm named Black Hole Algorithm (BHA) was developed to address the several well-known optimization problems. The BHA is a metaheuristic (population-based) that mimics the event around the natural phenomena of black holes, whereby an individual star represents the potential solutions revolving around the solution space. The original BHA algorithm showed better performance compared to other algorithms when applied to a benchmark dataset, despite its poor exploration capability. Hence, this paper presents a multi-population version of BHA as a generalization of the BHA called MBHA wherein the performance of the algorithm is not dependent on the best-found solution but a set of generated best solutions. The method formulated was subjected to testing using a set of nine widespread and popular benchmark test functions. The ensuing experimental outcomes indicated the highly precise results generated by the method compared to BHA and comparable algorithms in the study, as well as excellent robustness. Furthermore, the proposed MBHA achieved a high rate of convergence on six real datasets (collected from the UCL machine learning lab), making it suitable for DC problems. Lastly, the evaluations conclusively indicated the appropriateness of the proposed algorithm to resolve DC issues.
Fulltext Preparation and characterization of FsHA/FsCol beads: Cell attachment and cytotoxicity studies

Mudhafar M, Zainol I, Alsailawi HA, Zorah M, Karhib MM, Mahmood Mahdi N

Heliyon, 2023 May;9(5):e15838.
PMID: 37206015 DOI: 10.1016/j.heliyon.2023.e15838

The present study was conducted to prepare the fish scales' hydroxyapatite/collagen beads (FsHA/FsCol) and characterize their biological, physical, and chemical properties. A new method was used to prepare FsHA/FsCol composite beads by infiltrating the beads of FsHA in the solution of FsCol as a green method. X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) analysis, Fourier-transform infrared (FTIR) spectroscopy analysis and energy dispersive X-ray analysis (EDX), used to evaluate the physical-chemical properties of the synthesized samples. Meanwhile, the cytotoxic and attachment studies of the FsHA/FsCol beads were used to investigate the biological features against the MG-63 human cell line. The results specified the efficiency of the new method, functional groups of FsCol were indicated to be present inside the beads of FsHA according to the XRD analysis which shows the functional peaks of FsCol. The SEM image were conformed successfully use starch as a porous agent to increasing the porous of the FsHA beads after adding 20 wt% of it. Alamar Blue assay has been used to evaluate the cytotoxicity of FsHA/FsCol beads the results were shown 87% average cell viability of the MG-63 human cell line on the beads and attached very well to the surface of the composites, indicating no toxicity being exerted by all the composites at high concentrations.
The clinical implications of Porphyromonas gingivalis and its detection methods - a systematic review

Shalihin MSE, Suhaimi NAN, Hamzah HA, Abidin S, Aidid ME, Musa R

Med J Malaysia, 2023 Nov;78(6):830-844.
PMID: 38031228

INTRODUCTION: Mounting evidence has shown the significant correlation between periodontitis and the development of other comorbidities, such as cardiovascular disease due to periodontopathogenic bacterial migration and colonisation. As the main etiologic agent of periodontitis, the role of Porphyromonas gingivalis (P. gingivalis) has been widely explored as the main culprit and its early detection is crucial to control the exacerbation of diseases. This review aims to identify and summarise all clinical diseases that potentially developed due to the presence of P. gingivalis and discover all its detection methods that have been developed.
MATERIALS AND METHODS: Full-text articles of case report, case control, cohort and cross-sectional studies that were published from 1st January 2012 until 30th June 2022, were searched using PubMed, CINAHL and Scopus. Periodontal related diseases were excluded in this review due to its wellknown associated disease with P. gingivalis. A comparison studies of detection methods were also excluded in this review.
RESULTS: Out of 612 articles that were screened, only 106 met the eligibility criteria to be selected for further review. Risk of bias was performed using FEAT principles and reviewers' discussion. A total of 21 final articles that were reviewed showed significant correlation with P. gingivalis and were classified into several clinical domains. Twelve out of 13 detection methods showed high sensitivity and specificity with short duration analysis.
CONCLUSION: Due to asymptomatic periodontal disease and the high prevalence of P. gingivalis-associated clinical diseases, this review suggests the need for oral public health awareness and early screening for the bacterium detection especially among elderly groups to maintain their quality of life.
Removal of copper from water using limestone filtration technique. Determination of mechanism of removal

Aziz HA, Othman N, Yusuff MS, Basri DR, Ashaari FA, Adlan MN, et al.

Environ Int, 2001 May;26(5-6):395-9.
PMID: 11392757

This paper discusses heavy metal removal from wastewater by batch study and filtration technique through low-cost coarse media. Batch study has indicated that more than 90% copper (Cu) with concentration up to 50 mg/l could be removed from the solution with limestone quantity above 20 ml (equivalent to 56 g), which indicates the importance of limestone media in the removal process. This indicates that the removal of Cu is influenced by the media and not solely by the pH. Batch experiments using limestone and activated carbon indicate that both limestone and activated carbon had similar metal-removal efficiency (about 95%). Results of the laboratory-scale filtration technique using limestone particles indicated that above 90% removal of Cu was achieved at retention time of 2.31 h, surface-loading rate of 4.07 m3/m2 per day and Cu loading of 0.02 kg/m3 per day. Analyses of the limestone media after filtration indicated that adsorption and absorption processes were among the mechanisms involved in the removal processes. This study indicated that limestone can be used as an alternative to replace activated carbon.
Fulltext The total cost of rearing a heifer on Dutch dairy farms: calculated versus perceived cost

Mohd Nor N, Steeneveld W, Derkman TH, Verbruggen MD, Evers AG, de Haan MH, et al.

Ir Vet J, 2015;68:29.
PMID: 26675380 DOI: 10.1186/s13620-015-0058-x

As farmers do not often keep a record of the expenditures for rearing, an economic tool that provides insight into the cost of rearing is useful. In the Netherlands, an economic tool (Jonkos) has been developed that can be used by farmers to obtain insight into the cost of rearing on their farm. The first objective of this study is to calculate the total cost of rearing young stock in Dutch dairy herds using Jonkos. The second objective is to compare the calculated total cost of rearing with the farmers' own estimation of the cost of rearing (the perceived cost).
Carbon-based adsorbents for the mitigation of polycyclic aromatic hydrocarbon: a review of recent research

Shyamalagowri S, Bhavithra HA, Akila N, Jeyaraj SSG, Aravind J, Kamaraj M, et al.

Environ Geochem Health, 2024 Mar 07;46(3):108.
PMID: 38453774 DOI: 10.1007/s10653-024-01915-6

Accumulation of polycyclic aromatic hydrocarbons (PAH) poses significant dangers to the environment and human health. The advancement of technology for cleaning up PAH-contaminated environments is receiving more attention. Adsorption is the preferred and most favorable approach for cleaning up sediments polluted with PAH. Due to their affordability and environmental friendliness, carbonaceous adsorbents (CAs) have been regarded as promising for adsorbing PAH. However, adsorbent qualities, environmental features, and factors may all significantly impact how well CAs remove PAH. According to growing data, CAs, most of which come from laboratory tests, may be utilized to decontaminate PAH in aquatic setups. However, their full potential has not yet been established, especially concerning field applications. This review aims to concisely summarize recent developments in CA, PAH stabilization processes, and essential field application-controlling variables. This review analysis emphasizes activated carbon, biochar, Graphene, carbon nanotubes, and carbon-nanomaterials composite since these CAs are most often utilized as adsorbents for PAH in aquatic systems.
Fulltext Comparative study on photocatalytic activity of transition metals (Ag and Ni)-doped ZnO nanomaterials synthesized via sol-gel method

Azfar AK, Kasim MF, Lokman IM, Rafaie HA, Mastuli MS

R Soc Open Sci, 2020 Feb;7(2):191590.
PMID: 32257324 DOI: 10.1098/rsos.191590

Ag and Ni/ZnO photocatalyst nanostructures were successfully synthesized by a sol-gel method. In this work, the photocatalyst sample was systematically studied based on several factors affecting the performance of photocatalyst, which are size, morphology, band gap, textural properties and the number of active sites presence on the surface of the nanocatalyst. X-ray diffraction revealed that Ag/ZnO nanomaterials experienced multiple phases, meanwhile for Ni/ZnO the phase of nanomaterials were pure and single phase for stoichiometry less than 5%. Field emission scanning electron microscope (FESEM) showed almost all of the synthesized nanomaterials possessed a mixture of nanorods and spherical-like shape morphology. The Ag/ZnO showed high photocatalytic activity, producing at least 14th trials of nanocatalyst reusability on degradation of methyl orange under UV irradiation. Interestingly, this phenomenon was not observed in larger surface area of Ni/ZnO nanomaterials which supposedly favour photocatalytic activity, but instead producing poor photocatalytic performance. The main reasons were studied and exposed by temperature-programmed desorption of carbon dioxide (TPD-CO2) which showed that incorporation of Ag into ZnO lattice has enhanced the number of active sites on the surface of the nanocatalyst. Whereas incorporation of Ni in ZnO has lowered the number of active sites with respect to undoped ZnO. Active sites measurement is effective and significant, providing opportunities in developing an intensive study as an additional factor.
Fulltext Waterlogging tolerance of crops: breeding, mechanism of tolerance, molecular approaches, and future prospects

Ahmed F, Rafii MY, Ismail MR, Juraimi AS, Rahim HA, Asfaliza R, et al.

Biomed Res Int, 2013;2013:963525.
PMID: 23484164 DOI: 10.1155/2013/963525

Submergence or flood is one of the major harmful abiotic stresses in the low-lying countries and crop losses due to waterlogging are considerably high. Plant breeding techniques, conventional or genetic engineering, might be an effective and economic way of developing crops to grow successfully in waterlogged condition. Marker assisted selection (MAS) is a new and more effective approach which can identify genomic regions of crops under stress, which could not be done previously. The discovery of comprehensive molecular linkage maps enables us to do the pyramiding of desirable traits to improve in submergence tolerance through MAS. However, because of genetic and environmental interaction, too many genes encoding a trait, and using undesirable populations the mapping of QTL was hampered to ensure proper growth and yield under waterlogged conditions Steady advances in the field of genomics and proteomics over the years will be helpful to increase the breeding programs which will help to accomplish a significant progress in the field crop variety development and also improvement in near future. Waterlogging response of soybean and major cereal crops, as rice, wheat, barley, and maize and discovery of QTL related with tolerance of waterlogging, development of resistant variety, and, in addition, future prospects have also been discussed.
Fulltext Metamaterial sensor based on rectangular enclosed adjacent triple circle split ring resonator with good quality factor for microwave sensing application

Islam MR, Islam MT, M MS, Bais B, Almalki SHA, Alsaif H, et al.

Sci Rep, 2022 Apr 26;12(1):6792.
PMID: 35474227 DOI: 10.1038/s41598-022-10729-4

In this article, a novel shaped metamaterial sensor is presented for the recognition of various oils, fluids, and chemicals using microwave frequency. The performance of the designed sensor structure has been studied both theoretically and experimentally, and it works well. A new sample holder for convenient operation is created and located just behind the designed structure. The results of this study performed better than those of prior liquids sensing studies. Various designs were explored using the Genetic Algorithm (GA), and it is embedded in the Computer Simulation Technology (CST) microwave studio, to optimize the optimal dimensions of the resonator. The suggested metamaterial sensor has a good-quality factor and sensitivity in both frequency shifting and amplitude changing. The resonance frequency shifted to 100 MHz between olive and corn oils, 70 MHz between sunflower and palm oils, 80 MHz between clean and waste brake fluids, and 90 MHz between benzene and carbon-tetrachloride chemicals. The quality factor of the sensor is 135, sensitivity is 0.56, and the figure of merit is 76 which expresses its efficient performance. Furthermore, the proposed sensor can sensitively distinguish different liquids by using the frequency shifting property. The study was carried out in three stages: dielectric constant (DK) measurement with the N1500A dielectric measurement kit, simulation of the structure, and experimental test study with the vector network analyzer. Since the recommended sensor has high sensitivity, good quality factor, and excellent performance, hence it can be used in chemical, oil, and microfluidic industries for detecting various liquid samples.
Fulltext Author Correction: Metamaterial sensor based on rectangular enclosed adjacent triple circle split ring resonator with good quality factor for microwave sensing application

Islam MR, Islam MT, M MS, Bais B, Almalki SHA, Alsaif H, et al.

Sci Rep, 2024 Apr 29;14(1):9826.
PMID: 38684811 DOI: 10.1038/s41598-024-60569-7
Tumour lysis syndrome in a neonate with transient abnormal myelopoiesis

Mohammad Khuzaini A, Mohd Baharudin JA, Md Fauzi A, Zulkeflee HA, Abdul Halim H, Mazli SK, et al.

J Neonatal Perinatal Med, 2024;17(2):269-273.
PMID: 38728206 DOI: 10.3233/NPM-230146

BACKGROUND: Tumor lysis syndrome (TLS) is an oncological emergency associated with hematological malignancies or highly proliferative solid tumors, commonly after chemotherapy. It is rarely associated with transient abnormal myelopoiesis.
OBSERVATION: We report a rare case of a neonate with transient abnormal myelopoiesis and tumor lysis syndrome, complicated with concomitant heart failure due to an underlying atrioventricular septal defect. Hyperhydration was contraindicated due to heart failure. The patient was managed conservatively with full recovery.
CONCLUSION: Tumor lysis syndrome should be suspected in neonates with transient abnormal myelopoiesis with electrolyte abnormalities. Treatment options should be considered carefully for their risks and benefits.
Evaluation of TOPAS MC tool performance in optical photon transport and radioluminescence-based dosimetry

Khodaei A, Moradi F, Oresegun A, Zubair HT, Bradley DA, Ibrahim SA, et al.

Biomed Phys Eng Express, 2024 Aug 28;10(5).
PMID: 39142303 DOI: 10.1088/2057-1976/ad6f14

Radiation therapy plays a pivotal role in modern cancer treatment, demanding precise and accurate dose delivery to tumor sites while minimizing harm to surrounding healthy tissues. Monte Carlo simulations have emerged as indispensable tools for achieving this precision, offering detailed insights into radiation transport and interaction at the subatomic level. As the use of scintillation and luminescence dosimetry becomes increasingly prevalent in radiation therapy, there arises a need for validated Monte Carlo tools tailored to optical photon transport applications. In this paper, an evaluation process of the TOPAS (TOol for PArticle Simulation) Monte Carlo tool for Cerenkov light generation, optical photon transport and radioluminescence based dosimetry is presented. Three distinct sources of validation data are utilized: one from a published set of experimental results and two others from simulations performed with the Geant4 code. The methodology employed for evaluation includes the selection of benchmark experiments, making use of opt3 and opt4 Geant4 physics models and simulation setup, with observed slight discrepancies within the calculation uncertainties. Additionally, the complexities and challenges associated with modeling optical photons generation through luminescence or Cerenkov radiation and their transport are discussed. The results of our evaluation suggests that TOPAS can be used to reliably predict Cerenkov generation, luminescence phenomenon and the behavior of optical photons in common dosimetry scenarios.
Fulltext Balancing functional and health benefits of food products formulated with palm oil as oil sources

Sulaiman NS, Sintang MD, Mantihal S, Zaini HM, Munsu E, Mamat H, et al.

Heliyon, 2022 Oct;8(10):e11041.
PMID: 36303903 DOI: 10.1016/j.heliyon.2022.e11041

Palm oil (PO) is widely utilised in the food industry and consumed in large quantities by humans. Owing to its bioactive components, such as fatty acids, carotenoids, vitamin E, and phenolic compounds, PO has been utilised for generations. However, public concern about their adverse effects on human health is growing. A literature search was conducted to identify fractionated palm oil processing techniques, proof of their health advantages, and potential food applications. Refined palm oil (RPO) is made from crude palm oil (CPO) and can be fractionated into palm olein (POl) and palm stearin (PS). Fractional crystallisation, dry fractionation, and solvent fractionation are the three basic fractionation procedures used in the PO industry. The composition of triacylglycerols and fatty acids in refined and fractionated palm oil and other vegetable oils is compared to elucidate the triacylglycerols and fatty acids that may be important in product development. It is well proven that RPO, POl, and PS extends the oil's shelf life in the food business. These oils have a more significant saturated fat content and antioxidant compounds than some vegetable oils, such as olive and coconut oils, making them more stable. Palm olein and stearin are also superior shortening agents and frying mediums for baking goods and meals. Furthermore, when ingested modestly daily, palm oils, especially RPO and POl, provide health benefits such as cardioprotective, antidiabetic, anti-inflammatory, and antithrombotic effects. Opportunities exist for fractionated palm oil to become a fat substitute; however, nutrition aspects need to be considered in further developing the market.
Fulltext Through the Looking Glass: How the COVID-19 Pandemic Changed International Branch Campuses' Academic Experience and Home Campus Relationship

Merola RH, Coelen RJ, Hofman WHA, Jansen EPWA

J Stud Int Educ, 2023 Feb;27(1):3-20.
PMID: 36744242 DOI: 10.1177/10283153211070112

This study examines how the COVID-19 pandemic has impacted the academic experience at international branch campuses (IBCs) and has changed the relationship between the IBC and the home campus. Semi-structured interviews with 26 leaders, academic staff, and students at seven IBCs in Malaysia revealed that the COVID-19 pandemic has changed the experience at IBCs in unique ways, including collaboration and communication with the home campus; increasing campus-specific resources for student wellbeing; and playing a larger role in student enrollment, recruitment, and mobility initiatives. Findings provide useful insights for higher education institutions (HEIs) engaged in transnational education (TNE).
Dietary patterns in childhood and their effect on gut microbiota-an Asian perspective on atopy risk

Ismail IH, Lay C, H A Majid N, Lee WS, Lee BW, Abdul Latiff AH, et al.

J Allergy Clin Immunol, 2020 11;146(5):1005-1007.
PMID: 32860819 DOI: 10.1016/j.jaci.2020.05.057
Fulltext Identification of genotypes of Influenza A virus in Malaysia

Mm R, Kk W, I I, Zz R, H A

Pak J Med Sci, 2014 Sep;30(5):1068-71.
PMID: 25225528 DOI: 10.12669/pjms.305.5224

OBJECTIVE: Influenza is considered as an emerging disease until today. The present study was undertaken to determine the prevalent genotypes of Influenza A virus in Malaysia.
METHODS: Influenza A virus was identified from respiratory specimens by real-time reverse transcriptase polymerase chain reaction (rRT-PCR). Phylogenetic analysis of the identified isolates was performed and genotypes were detected.
RESULTS: A total number of 505 throat swabs and nasopharyngeal aspirates were examined by rRT-PCR at Universiti Kebangsaan Malaysia Medical Centre (UKMMC) in which 65(12.87%) were positive for influenza A. The identified isolates were successfully genotyped by phylogenetic analysis. The identified influenza A genotypes were: H1N1 (42), H3N2 (20) and H5N1 (3).
CONCLUSION: The findings indicated that 3 genotypes were circulating in Malaysia during 2011 in which H1N1 was the predominant. RESULTS added new genotype (H5N1) identification record in Malaysia that may be added in data base of WHO and CDC.
Thermoluminescence characteristics of Ge-doped optical fibers with different dimensions for radiation dosimetry

Begum M, Rahman AK, Abdul-Rashid HA, Yusoff Z, Begum M, Mat-Sharif KA, et al.

Appl Radiat Isot, 2015 Jun;100:79-83.
PMID: 25468288 DOI: 10.1016/j.apradiso.2014.10.025

Important thermoluminescence (TL) properties of five (5) different core sizes Ge-doped optical fibers have been studied to develop new TL material with better response. These are drawn from same preform applying different speed and tension during drawing phase to produce Ge-doped optical fibers with five (5) different core sizes. The results of the investigations are also compared with most commonly used standard TLD-100 chips (LiF:Mg,Ti) and commercial multimode Ge-doped optical fiber (Yangtze Optical Fiber, China). Scanning Electron Microscope (SEM) and EDX analysis of the fibers are also performed to map Ge distribution across the deposited region. Standard Gamma radiation source in Secondary Standard Dosimetry Lab (SSDL) was used for irradiation covering dose range from 1Gy to 10Gy. The essential dosimetric parameters that have been studied are TL linearity, reproducibility and fading. Prior to irradiation all samples ∼0.5cm length are annealed at temperature of 400°C for 1h period to standardize their sensitivities and background. Standard TLD-100 chips are also annealed for 1h at 400°C and subsequently 2h at 100°C to yield the highest sensitivity. TL responses of these fibers show linearity over a wide gamma radiation dose that is an important property for radiation dosimetry. Among all fibers used in this study, 100μm core diameter fiber provides highest response that is 2.6 times than that of smallest core (20μm core) optical fiber. These fiber-samples demonstrate better response than commercial multi-mode optical fiber and also provide low degree of fading about 20% over a period of fifteen days for gamma radiation. Effective atomic number (Zeff) is found in the range (13.25-13.69) which is higher than soft tissue (7.5) however within the range of human-bone (11.6-13.8). All the fibers can also be re-used several times as a detector after annealing. TL properties of the Ge-doped optical fibers indicate promising applications in ionizing radiation dosimetry.
The thermoluminescence characteristics and the glow curves of Thulium doped silica fiber exposed to 10MV photon and 21MeV electron radiation

Alawiah A, Alina MS, Bauk S, Abdul-Rashid HA, Gieszczyk W, Noramaliza MN, et al.

Appl Radiat Isot, 2015 Apr;98:80-6.
PMID: 25644081 DOI: 10.1016/j.apradiso.2015.01.016

The thermoluminescence (TL) glow curves and kinetics parameters of Thulium (Tm) doped silica cylindrical fibers (CF) are presented. A linear accelerator (LINAC) was used to deliver high-energy radiation of 21MeV electrons and 10MV photons. The CFs were irradiated in the dose range of 0.2-10Gy. The experimental glow curve data was reconstructed by using WinREMS. The WinGCF software was used for the kinetic parameters evaluation. The TL sensitivity of Tm-doped silica CF is about 2 times higher as compared to pure silica CF. Tm-doped silica CF seems to be more sensitive to 21MeV electrons than to 10MV photons. Surprisingly, no supralinearity was displayed and a sub-linear response of Tm-doped silica CF was observed within the analyzed dose range for both 21MeV electrons and 10MV photons. The Tm-doped silica CF glow curve consists of 5 individual glow peaks. The Ea of peak 4 and peak 5 was highly dependent on dose when irradiated with photons. We also noticed that the electron radiation (21MeV) caused a shift of glow peak by 7-13°C to the higher temperature region compared with photons radiation (10MV). Our Tm-doped fibers seem to give high TL response after 21MeV electrons, which gives around 2 times higher peak integral as compared with 10MV photon radiation. We concluded that peak 4 is the first-order kinetic peak and can be used as the main dosimetric peak of Tm-doped silica CF.

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