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Fulltext Functional Properties of Antimicrobial Neem Leaves Extract Based Macroalgae Biofilms for Potential Use as Active Dry Packaging Applications

Oyekanmi AA, Kumar USU, H P S AK, Olaiya NG, Amirul AA, Rahman AA, et al.

Polymers (Basel), 2021 May 20;13(10).
PMID: 34065404 DOI: 10.3390/polym13101664

Antimicrobial irradiated seaweed-neem biocomposite films were synthesized in this study. The storage functional properties of the films were investigated. Characterization of the prepared films was conducted using SEM, FT-IR, contact angle, and antimicrobial test. The macroscopic and microscopic including the analysis of the functional group and the gas chromatography-mass spectrometry test revealed the main active constituents present in the neem extract, which was used an essential component of the fabricated films. Neem leaves' extracts with 5% w/w concentration were incorporated into the matrix of seaweed biopolymer and the seaweed-neem bio-composite film were irradiated with different dosages of gamma radiation (0.5, 1, 1.5, and 2 kGy). The tensile, thermal, and the antimicrobial properties of the films were studied. The results revealed that the irradiated films exhibited improved functional properties compared to the control film at 1.5 kGy radiation dosage. The tensile strength, tensile modulus, and toughness exhibited by the films increased, while the elongation of the irradiated bio-composite film decreased compared to the control film. The morphology of the irradiated films demonstrated a smoother surface compared to the control and provided surface intermolecular interaction of the neem-seaweed matrix. The film indicated an optimum storage stability under ambient conditions and demonstrated no significant changes in the visual appearance. However, an increase in the moisture content was exhibited by the film, and the hydrophobic properties was retained until nine months of the storage period. The study of the films antimicrobial activities against Staphylococcus aureus (SA), and Bacillus subtilis (BS) indicated improved resistance to bacterial activities after the incorporation of neem leaves extract and gamma irradiation. The fabricated irradiated seaweed-neem bio-composite film could be used as an excellent sustainable packaging material due to its effective storage stability.

Matched MeSH terms: Gamma Rays
Sistem pemarkahan berasaskan pemberat dan persentil taburan

Hamizun Ismail, Azmin Sham Rambely, Rokiah Rozita Ahmad

Sains Malaysiana, 2012;41:1043-1049.

Kaedah pemarkahan dan penggredan sering dibincangkan dalam aspek penilaian pelajar. Kertas kerja ini bertujuan untuk membincangkan kaedah pemarkahan dan penggredan menggunakan persentil taburan markah. Kaedah pemarkahan dengan menggunakan min dan songsangan varians markah bagi setiap soalan dalam suatu peperiksaan sebagai pemberat kepada soalan berkenaan dibincangkan. Dalam membincangkan penggredan menggunakan persentil taburan markah, persentil boleh ditentukan dengan menganggar taburan bagi markah peperiksaan. Penganggaran dan penentuan persentil bagi dua taburan iaitu taburan normal dan taburan gamma digunakan. Perbandingan dilakukan terhadap keputusan bagi beberapa senario yang diperoleh. Keputusan menunjukkan bahawa kaedah pemarkahan berpemberat yang menggunakan pemberat yang berasaskan kepada tahap kesukaran soalan boleh digunakan untuk mernghasilkan peringkat gred yang lebih jelas dalam kalangan pelajar.

Matched MeSH terms: Gamma Rays
Imputing missing values in modelling the PM10 concentrations

Nuradhiathy Abd Razak, Yong Zulina Zubairi, Rossita M. Yunus

Sains Malaysiana, 2014;43:1599-1607.

Missing values have always been a problem in analysis. Most exclude the missing values from the analyses which may lead to biased parameter estimates. Some imputations methods are considered in this paper in which simulation study is conducted to compare three methods of imputation namely mean substitution, hot deck and expectation maximization (EM) imputation. The EM imputation is found to be superior especially when the percentage of missing values is high as it constantly gives low RMSE as compared with other two methods. The EM imputation method is then applied to the PM10 concentrations data set for the southwest and northeast monsoons in Petaling Jaya and Seberang Perai, Malaysia which has missing values. Four types of distributions, namely the Weibull, lognormal, gamma and Gumbel distribution are considered to describe the PM10 concentrations. The Weibull distribution gives the best fit for the southwest monsoon data for Petaling Jaya. The lognormal distribution outperformed the others in describing the southwest monsoon in Seberang Perai. Meanwhile, for the northeast monsoon in both locations, gamma distribution is the best distribution to describe the data.

Matched MeSH terms: Gamma Rays
Measurement of the viscosity of irradiated silicone using a differential viscometer

Bradley DA, Dahlan KZ, Roy SC

Appl Radiat Isot, 2000 Oct;53(4-5):921-8.
PMID: 11003542

High-energy electron (2.0 MV) and gamma irradiation (60Co) has been used to modify polymeric silicone fluids of initial viscosities in the range, 90-700 cSt. Doses of electron and gamma radiation were delivered at rates of 0.246 kGy s(-1) and 15 kGy h(-1), respectively, exposure times being adjusted to ensure energy deposition in the range 30-360 kGy. Measurements were made using a differential viscometer based on a Bose Institute design. In line with expectation, samples of greater initial molecular weight (and hence greater viscosity), were observed to be more susceptible to radiation induced cross-linking than those of lower molecular weight. The role of dose rate and oxygen diffusion in determining the extent of change is discussed.

Matched MeSH terms: Gamma Rays
Assessment of health hazard due to natural radioactivity in Kluang District, Johor, Malaysia

Aziz Saleh M, Termizi Ramli A, Alajerami Y, Damoom M, Sadiq Aliyu A

Isotopes Environ Health Stud, 2014;50(1):103-13.
PMID: 24279290 DOI: 10.1080/10256016.2013.821469

The radiation survey of the ambient environment was conducted using two gamma detectors, and the measurement results were used in the computation of the mean external radiation dose rate, mean-weighted dose rate and annual effective dose, which are 144 nGy h(-1), 0.891 mSv y(-1) and 178 μSv, respectively. A high-purity germanium detector was used to determine the activity concentrations of (232)Th, (226)Ra and (40)K in soil samples. The results of the gamma spectrometry of the soil samples show radioactivity concentration ranges from 19±1 to 405±13 Bq kg(-1) with a mean value of 137±5 Bq kg(-1) for (232)Th, from 21±2 to 268±9 Bq kg(-1)with a mean value of 78±3 Bq kg(-1) for (226)Ra and from 23±9 to 1268±58 Bq kg(-1) with a mean value of 207±13 Bq kg(-1) for (40)K. Radium equivalent activity (Raeq) and external hazard index (Hex) were 290 Bq kg(-1) and 0.784, respectively, which were safe for the population. The mean lifetime dose and lifetime cancer risk for each person living in the area with average lifetime (70 y) were 12.46 mSv and 7.25×10(-4) Sv year, respectively. The results were compared with values given in United Nations Scientific Committee on the Effects of Atomic Radiation 2000.

Matched MeSH terms: Gamma Rays
Prediction of terrestrial gamma dose rate based on geological formations and soil types in the Johor State, Malaysia

Saleh MA, Ramli AT, bin Hamzah K, Alajerami Y, Moharib M, Saeed I

J Environ Radioact, 2015 Oct;148:111-22.
PMID: 26142818 DOI: 10.1016/j.jenvrad.2015.05.019

This study aims to predict and estimate unmeasured terrestrial gamma dose rate (TGDR) using statistical analysis methods to derive a model from the actual measurement based on geological formation and soil type. The measurements of TGDR were conducted in the state of Johor with a total of 3873 measured points which covered all geological formations, soil types and districts. The measurements were taken 1 m above the soil surface using NaI [Ti] detector. The measured gamma dose rates ranged from 9 nGy h(-1) to 1237 nGy h(-1) with a mean value of 151 nGy h(-1). The data have been normalized to fit a normal distribution. Tests of significance were conducted among all geological formations and soil types, using the unbalanced one way ANOVA. The results indicated strong significant differences due to the different geological formations and soil types present in Johor State. Pearson Correlation was used to measure the relations between gamma dose rate based on geological formation and soil type (D(G,S)) with the gamma dose rate based on geological formation (D(G)) or soil type (D(s)). A very good correlation was found between D(G,S) and D(G) or D(G,S) and D(s). A total of 118 pairs of geological formations and soil types were used to derive the statistical contribution of geological formations and soil types to gamma dose rates. The contribution of the gamma dose rate from geological formation and soil type were found to be 0.594 and 0.399, respectively. The null hypotheses were accepted for 83% of examined data, therefore, the model could be used to predict gamma dose rates based on geological formation and soil type information.

Matched MeSH terms: Gamma Rays*
Isodose mapping of terrestrial gamma radiation dose rate of Selangor state, Kuala Lumpur and Putrajaya, Malaysia

Sanusi MS, Ramli AT, Gabdo HT, Garba NN, Heryanshah A, Wagiran H, et al.

J Environ Radioact, 2014 Sep;135:67-74.
PMID: 24787672 DOI: 10.1016/j.jenvrad.2014.04.004

A terrestrial gamma radiation survey for the state of Selangor, Kuala Lumpur and Putrajaya was conducted to obtain baseline data for environmental radiological health practices. Based on soil type, geological background and information from airborne survey maps, 95 survey points statistically representing the study area were determined. The measured doses varied according to geological background and soil types. They ranged from 17 nGy h(-1) to 500 nGy h(-1). The mean terrestrial gamma dose rate in air above the ground was 182 ± 81 nGy h(-1). This is two times higher than the average dose rate of terrestrial gamma radiation in Malaysia which is 92 nGy h(-1) (UNSCEAR 2000). An isodose map was produced to represent exposure rate from natural sources of terrestrial gamma radiation.

Matched MeSH terms: Gamma Rays*
Sub kGy photon irradiation alterations in graphite

Bradley DA, Nawi SNM, Khandaker MU, Almugren KS, Sani SFA

Appl Radiat Isot, 2020 Jul;161:109168.
PMID: 32321700 DOI: 10.1016/j.apradiso.2020.109168

Present work concerns polymer pencil-lead graphite (PPLG) and the potential use of these in elucidating irradiation-driven structural alterations. The study provides detailed analysis of radiation-induced structural interaction changes and the associated luminescence that originates from the energy absorption. Thermally stimulated emission from the different occupied defect energy levels reflects the received radiation dose, different for the different diameter PPLGs. The PPLG samples have been exposed to photon irradiation, specifically x-ray doses ranging from 1 to 10 Gy, extended to 30-200 Gy through use of a60Co gamma-ray source. Trapping parameters such as order of kinetics, activation energy and frequency factor are estimated using Chen's peak-shape method for a fixed-dose of 30 Gy. X-ray diffractometry was used to characterize the crystal structure of the PPLG, the aim being to identify the degree of structural order, atomic spacing and lattice constants of the various irradiated PPLG samples. The mean atomic spacing and degree of structural order for the different diameter PPLG are found to be 0.3332 nm and 26.6° respectively. Photoluminescence spectra from PPLG arising from diode laser excitation at 532 nm consist of two adjacent peaks, 602 nm (absorption) and 1074 nm (emission), with mean energy band gap values within the range 1.113-1.133 eV.

Matched MeSH terms: Gamma Rays
Natural radioactivity measurements in Pahang State, Malaysia

Gabdo HT, Ramli AT, Saleh MA, Garba NN, Sanusi M

Isotopes Environ Health Stud, 2016 Jun;52(3):298-308.
PMID: 26999725 DOI: 10.1080/10256016.2016.1128428

This study was aimed at providing the baseline data of terrestrial gamma dose rates and natural radioactivity to assess the corresponding health risk in the ambient environment of the Pahang State. Terrestrial gamma radiation (TGR) from 640 locations was measured with the mean value found to be 176 ± 5 nGy h(-1). Ninety-eight soil samples were analysed using a high-purity germanium detector (HPGe), and the mean concentrations of the radionuclides (226)Ra, (232)Th and (40)K are 110 ± 3, 151 ± 5 and 542 ± 51 Bq kg(-1), respectively.(226)Ra and (232)Th concentrations were found to be three times the world average, while that of (40)K is quite higher than the world average value. The acid-intrusive geological formation has the highest mean concentrations for (226)Ra (215 ± 6 Bq kg(-1)), (232)Th (384 ± 12 Bq kg(-1)) and (40)K (1564 ± 153 Bq kg(-1)). The radium equivalent activities (Req) and the external hazard index (Hex) for the various soil types were also calculated. Some of the soil types were found to have values exceeding the internationally recommended levels of 370 Bq kg(-1) and the unity value, respectively.

Matched MeSH terms: Gamma Rays*
Fulltext Synthesis of silver/montmorillonite nanocomposites using γ-irradiation

Shameli K, Ahmad MB, Yunus WM, Ibrahim NA, Gharayebi Y, Sedaghat S

Int J Nanomedicine, 2010 Dec 01;5:1067-77.
PMID: 21170354 DOI: 10.2147/IJN.S15033

Silver nanoparticles (Ag-NPs) were synthesized into the interlamellar space of montmorillonite (MMT) by using the γ-irradiation technique in the absence of any reducing agent or heat treatment. Silver nitrate and γ-irradiation were used as the silver precursor and physical reducing agent in MMT as a solid support. The MMT was suspended in the aqueous AgNO(3) solution, and after the absorption of silver ions, Ag(+) was reduced using the γ-irradiation technique. The properties of Ag/MMT nanocomposites and the diameters of Ag-NPs were studied as a function of γ-irradiation doses. The interlamellar space limited particle growth (d-spacing [d(s)] = 1.24-1.42 nm); powder X-ray diffraction and transmission electron microscopy (TEM) measurements showed the production of face-centered cubic Ag-NPs with a mean diameter of about 21.57-30.63 nm. Scanning electron microscopy images indicated that there were structure changes between the initial MMT and Ag/MMT nanocomposites under the increased doses of γ-irradiation. Furthermore, energy dispersive X-ray fluorescence spectra for the MMT and Ag/ MMT nanocomposites confirmed the presence of elemental compounds in MMT and Ag-NPs. The results from ultraviolet-visible spectroscopy and TEM demonstrated that increasing the γ-irradiation dose enhanced the concentration of Ag-NPs. In addition, the particle size of the Ag-NPs gradually increased from 1 to 20 kGy. When the γ-irradiation dose increased from 20 to 40 kGy, the particle diameters decreased suddenly as a result of the induced fragmentation of Ag-NPs. Thus, Fourier transform infrared spectroscopy suggested that the interactions between Ag-NPs with the surface of MMT were weak due to the presence of van der Waals interactions. The synthesized Ag/MMT suspension was found to be stable over a long period of time (ie, more than 3 months) without any sign of precipitation.

Matched MeSH terms: Gamma Rays*
Fulltext Assessment of the genetic variability and fibre composition of Gamma Ray induced mutant lines of Ginger (Zingiber Officinale Roscoe)

Nor Yusliza Kamaruddin, Shamsiah Abdullah

Pertanika Journal of Science & Technology, 2017;25(103):325-334.
MyJurnal

This study looked at mutagenic effectiveness of gamma rays d on two varieties of Zingiber officinale Roscoe: Bentong and Tanjung Sepat. The rhizomes were exposed to different doses (0, 5, 7, 9, 11, 13 and 15 Gy) using Caesium-137 as source of the gamma rays. The effect of different gamma doses on the crude fibre composition of irradiated ginger was studied and genetic variability was assessed using molecular marker technique, RAPD. Findings showed different doses of gamma rays could induce variability in these two ginger varieties and the effect was found to be variety-dependent. Bentong variety irradiated with 9 Gy recorded 8.53% of crude fibre composition while Tanjung Sepat irradiated ginger with 5 Gy recorded 8.70% of crude fibre which gave the lowest composition compared with other irradiated ginger. A total of nine different arbitrary decamers were used as primers to amplify DNA from mutant plant material to assess their polymorphism level of ginger mutant lines. Polymorphism of all mutant lines was 97.62% indicating that there were significant changes in genetic sequences in irradiated ginger genotypes.

Matched MeSH terms: Gamma Rays
Fulltext Gamma irradiation effects on oil palm (elaies guinensis jacq.) pollen viability, fruits and bunch formations

Aida Nazlyn Nazari, Azhar Mohamad, Shuhaimi Shamsudin

Jurnal Sains Nuklear Malaysia, 2014;26(2):1-8.
MyJurnal

Assessing performance and genetic diversity of the wild material of oil palm is important for
under- standing genetic structure of natural oil palm populations towards improvement of the
crops. This in-formation is important for oil palm breeding programs, and also for continued exsitu
conservation of the germplasm and breeding program in Malaysia. Mutation induction is one
of the approaches in creating variants for selection in the breeding program. In this study, the
effect of irradiated pollen towards pollen viability, bunches formation and number of
parthenocarpic fruits were evaluated. Elaies guineensis Jacq. pollens were exposed to series of
acute gamma radiation at dose 0, 10, 20, 40, 50, 100, 200, 300, 500, 100 and 2000 Gy . Pollen
viability and pollen tube formation were disrupted in which unable the pollen to reach the ovule.
At this stage, embryo was aborted towards formation of parthenocarpic fruits and rotten bunches.
The study suggested that at low levels of irradiation i.e. < 200 Gy, generative nucleus partially
damage and it is still maintaining capacity of fertilizing the egg cells for hybridization. It is
important for breeders in understanding this finding towards novel variants of oil palm via
mutation induction

Matched MeSH terms: Gamma Rays
Fulltext Effects of acute and chronic gamma irradiation on in vitro growth of stevia rebaudiana bertoni

Norazlina Noordin, Rusli Ibrahim, Nur Hidayah Mohd Sajahan, Salmah Moosa, Sobri Hussein

Jurnal Sains Nuklear Malaysia, 2014;26(2):17-25.
MyJurnal

Stevia rebaudiana Bertoni is a perennial herb that belongs to the family of Asteraceae. It is a
natural sweetener plant known as sweet leaf, which is estimated to be 300 times sweeter than cane
sugar. In this study, micropropagation and in vitro mutagenesis of this natural herb was
successfully conducted. It was found that shoot tips on MS medium supplemented with 1 mg/l
Kinetin showed the highest shoot induction and multiplication after 3 weeks of culture
(5.50±1.95a). Radiosensitivity test was conducted to identify the dose that killed 50% of the
irradiated explants (LD50) for in vitro stevia shoots and to select effective doses to be used for the in
vitro mutagenesis. Shoot tips were irradiated with acute and chronic gamma radiation at 0, 10, 20,
30, 40, 60, and 80Gy. At 60 Gy and 80 Gy, all treated shoot tips were not survived. In this study,
LD50 for the stevia was estimated at 29 Gy for acute irradiation and 45 Gy for chronic irradiation.
The effective doses were selected at 10, 20, 30 and 40 Gy. These selected doses were applied for the
in vitro mutagenesis of the stevia shoots

Matched MeSH terms: Gamma Rays
Fulltext Room temperature radiolytic synthesized Cu@CuAlO(2)-Al(2)O(3) nanoparticles

Abedini A, Saion E, Larki F, Zakaria A, Noroozi M, Soltani N

Int J Mol Sci, 2012;13(9):11941-53.
PMID: 23109893 DOI: 10.3390/ijms130911941

Colloidal Cu@CuAlO(2)-Al(2)O(3) bimetallic nanoparticles were prepared by a gamma irradiation method in an aqueous system in the presence of polyvinyl pyrrolidone (PVP) and isopropanol respectively as a colloidal stabilizer and scavenger of hydrogen and hydroxyl radicals. The gamma irradiation was carried out in a (60)Co gamma source chamber with different doses up to 120 kGy. The formation of Cu@CuAlO(2)-Al(2)O(3) nanoparticles was observed initially by the change in color of the colloidal samples from colorless to brown. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of bonds between polymer chains and the metal surface at all radiation doses. Results of transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDX), and X-ray diffraction (XRD) showed that Cu@CuAlO(2)-Al(2)O(3) nanoparticles are in a core-shell structure. By controlling the absorbed dose and precursor concentration, nanoclusters with different particle sizes were obtained. The average particle diameter increased with increased precursor concentration and decreased with increased dose. This is due to the competition between nucleation, growth, and aggregation processes in the formation of nanoclusters during irradiation.

Matched MeSH terms: Gamma Rays*
Micellar electrokinetic chromatography method for the simultaneous determination of furanic compounds in honey and vegetable oils

Foo Wong Y, Makahleh A, Al Azzam KM, Yahaya N, Saad B, Sulaiman SA

Talanta, 2012 Aug 15;97:23-31.
PMID: 22841043 DOI: 10.1016/j.talanta.2012.03.056

A simple micellar electrokinetic chromatography (MEKC) method for the simultaneous determination of 2-furfural (2-F), 3-furfural (3-F), 5-methylfurfural (5-MF), 5-hydroxymethylfurfural (5-HMF), 2-furoic acid (2-FA) and 3-furoic acid (3-FA) in honey and vegetable oils is described. Parameters affecting the separation such as pH, buffer and surfactant concentrations, applied voltage, capillary temperature, injection time and capillary length were studied and optimized. The separation was carried out in normal polarity mode at 20 °C, 22 kV and using hydrodynamic injection (17 s). The separation was achieved in a bare fused-silica capillary (46 cm × 50 μm i.d.) with a background electrolyte of 75 mM phosphoric acid (pH 7.3), containing 200 mM of sodium dodecyl sulphate (SDS). The detection wavelengths were at 200 nm (2-FA and 3-FA) and 280 nm (2-F, 3-F, 5-MF, 5-HMF). The furfurals were well separated in less than 20 min. The method was validated in terms of linearity, limit of detection and quantitation, precision and recoveries. Calibration curves of the six furfurals were well correlated (r(2)>0.991) within the range 1-25 μg mL(-1). Relative standard deviations of intra- and inter-day migration times and corrected peak areas ≤9.96% were achieved. The limit of detection (signal:noise, 3) was 0.33-0.70 μg mL(-1) whereas the limit of quantitation (signal:noise, 10) was 1.00-2.12 μg mL(-1). The method was applied to the determination of furanic compounds in honeys and vegetable oils (palm, walnut, grape seed and rapeseed). The effects of thermal treatment and gamma irradiation on the formation of the furanic compounds in honey were also investigated.

Matched MeSH terms: Gamma Rays
Studies on the antioxidant properties of Tualang honey of Malaysia

Mohamed M, Sirajudeen K, Swamy M, Yaacob NS, Sulaiman SA

Afr J Tradit Complement Altern Med, 2009 Oct 15;7(1):59-63.
PMID: 21304614

Honey has been used since ancient times for its nutritional as well as curative properties. Tualang honey is collected from wild honey bees' hives on Tualang trees found in the Malaysian rain forest. It has been used traditionally for the treatment of various diseases, where its therapeutic value has partly been related to its antioxidant properties. This study therefore assessed the colour intensity, total phenolic content, antioxidant activity and antiradical activity of gamma irradiated Tualang Honey. The colour intensity at ABS₄₅₀ was 489.5 ± 1.7 mAU, total phenolic content was 251.7 ± 7.9 mg (gallic acid) /Kg honey, total antioxidant activity by FRAP assay was 322.1 ± 9.7 (µM Fe(II)) and the antiradical activity by DPPH assay was 41.30 ± 0.78 (% inhibition). The data confirms that the antioxidant properties of gamma irradiated Tualang honey are similar to other types of honeys reported in the literature.

Matched MeSH terms: Gamma Rays
Radioactivity associated with amang upgrading plants

Hu SJ, Koo WK, Tan KL

Health Phys, 1984 Feb;46(2):452-5.
PMID: 6693279
Matched MeSH terms: Gamma Rays
Fulltext Gamma-Irradiation Induced Functionalization of Graphene Oxide with Organosilanes

Aujara KM, Chieng BW, Ibrahim NA, Zainuddin N, Thevy Ratnam C

Int J Mol Sci, 2019 Apr 18;20(8).
PMID: 31003413 DOI: 10.3390/ijms20081910

Gamma-ray radiation was used as a clean and easy method for turning the physicochemical properties of graphene oxide (GO) in this study. Silane functionalized-GO were synthesized by chemically grafting 3-aminopropyltriethoxysilane (APTES) and 3-glycidyloxypropyltrimethoxysilane (GPTES) onto GO surface using gamma-ray irradiation. This established non-contact process is used to create a reductive medium which is deemed simpler, purer and less harmful compared conventional chemical reduction. The resulting functionalized-GO were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), and Raman spectroscopy. The chemical interaction of silane with the GO surface was confirmed by FT-IR. X-ray diffraction reveals the change in the crystalline phases was due to surface functionalization. Surface defects of the GO due to the introduction of silane mioties was revealed by Raman spectroscopy. Thermogravimetric analysis of the functionalized-GO exhibits a multiple peaks in the temperature range of 200-650 °C which corresponds to the degradation of chemically grafted silane on the GO surface.

Matched MeSH terms: Gamma Rays
Fulltext Estimation of (99)Mo production rates from natural molybdenum in research reactors

Blaauw M, Ridikas D, Baytelesov S, Salas PS, Chakrova Y, Eun-Ha C, et al.

J Radioanal Nucl Chem, 2017;311(1):409-418.
PMID: 28111485 DOI: 10.1007/s10967-016-5036-6

Molybdenum-99 is one of the most important radionuclides for medical diagnostics. In 2015, the International Atomic Energy Agency organized a round-robin exercise where the participants measured and calculated specific saturation activities achievable for the (98)Mo(n,γ)(99)Mo reaction. This reaction is of interest as a means to locally, and on a small scale, produce (99)Mo from natural molybdenum. The current paper summarises a set of experimental results and reviews the methodology for calculating the corresponding saturation activities. Activation by epithermal neutrons and also epithermal neutron self-shielding are found to be of high importance in this case.

Matched MeSH terms: Gamma Rays
Fulltext Bystander Effect Induced in Breast Cancer (MCF-7) and Human Osteoblast Cell Lines (hFOB 1.19) with HDR-Brachytherapy

Zainudin Nh M, R A, W N R

J Biomed Phys Eng, 2020 Jun;10(3):319-328.
PMID: 32637376 DOI: 10.31661/jbpe.v0i0.1135

Background: Radiation induced bystander effects (RIBEs) occurs in unirradiated cells exhibiting indirect biological effect as a consequence of signals from other irradiated cells in the population.
Objective: In this study, bystander effects in MCF-7 breast cancer cells and hFOB 1.19 normal osteoblast cells irradiated with gamma emitting HDR Brachytherapy Ir-192 source were investigated.
Material and Methods: In this in-vitro study, bystander effect stimulation was conducted using medium transfer technique of irradiated cells to the non-irradiated bystander cells. Cell viability, reactive oxygen species (ROS) generation and colony forming assay was employed to evaluate the effect.
Results: Results indicate that the exposure to the medium irradiated MCF-7 induced significant bystander killing and decreased the survival fraction of bystander MCF-7 and hFOB from 1.19 to 81.70 % and 65.44 %, respectively. A significant decrease in survival fraction was observed for hFOB 1.19 bystander cells (p < 0.05). We found that the rate of hFOB 1.19 cell growth significantly decreases to 85.5% when added with media from irradiated cells. The ROS levels of bystander cells for both cell lines were observed to have an increase even after 4 h of treatment. Our results suggest the presence of bystander effects in unirradiated cells exposed to the irradiated medium.
Conclusion: These data provide evidence that irradiated MCF-7 breast cancer cells can induce bystander death in unirradiated MCF-7 and hFOB 1.19 bystander cells. Increase in cell death could also be mediated by the ROS generation during the irradiation with HDR brachytherapy.

Matched MeSH terms: Gamma Rays

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