Increase In Gamma Irradiation Dose Research Articles

Response of Satureja hortensis L. to gamma radiation and its impact on secondary metabolite content and biochemical characteristics

Purpose The current study investigated the effects of gamma irradiation on biochemical parameters and secondary metabolite accumulation in Summer Savory under field conditions. Materials and methods The dry seeds of Summer Savory (with a moisture content of 12%) were exposed to gamma radiation at the doses of 20, 40, 60, 80, and 100 Gy. Non-irradiated seeds (0 Gy) were used as control. Results Our findings showed that gamma radiation at low doses (20–40 Gy) had no effect on biochemical parameters and secondary metabolites accumulation in S. hortensis. These parameters are steadily and significantly increased by raising gamma irradiation doses from 40 to 100 Gy. The highest amount of chlorophyll a and b, carotenoids, anthocyanin, and total phenolic and flavonoid content were observed in 80 and 100 Gy treatments. Plants exposed to 80 and 100 Gy treatments accumulated the maximum amounts of rosmarinic acid and caffeic acid, respectively. Furthermore, the analysis of S. hortensis essential oil revealed that gamma radiation significantly alters its components. Carvacrol, α-Pinene, and α-Thujene levels raised dramatically compared to control with an increase in gamma irradiation dose from 20 to 100 Gy, while Thymol and α-Terpinene levels lowered. Conclusions Our results showed that treatment of Summer Savory seeds with gamma radiation at 80 and 100 Gy doses could significantly be raised biochemical parameters and secondary metabolites accumulation under field conditions. The current study showed that gamma irradiation could be used as a pre-sowing elicitor to improve the quantity and quality of phytochemicals in Summer Savory.

Gamma degraded oligomeric nanochitosan for adsorptive removal of Cd(II)

This study is the first ever report of application of gamma degraded nanochitosan biopolymer for the adsorptive removal of Cd(II) from aqueous systems. The viscosity studies revealed that the average molecular weight goes on decreasing with increase in gamma irradiation dose. The degraded products were subjected to characterization and were used for adsorption of Cd(II) in aqueous medium showing optimum adsorption capacity of 47.6 mg g−1 at 10 kGy dose in nice accordance with Freundlich model of isotherm and followed pseudo-second order rate expression. The crystallite size of chitosan was found to reduce from 39.15 nm to 7.012 nm with 10 kGy dose.

Effect of Gamma-irradiation on the Physicochemical, Functional, and Antioxidant Properties of Unpigmented Brown Whole Rice Flour.

Whole grain brown rice, being a rich source of fiber and other bioactive compounds like polyphenols is effective in reducing the risk of chronic diseases including cardiovascular diseases, hypercholesterolemia and Type II diabetes. The study was aimed to evaluate the effect of gamma irradiation on the physicochemical, functional and antioxidant properties of whole grain brown rice flour. The brown rice flour was conditioned to two different moisture contents of 10% and 12% and treated with gamma irradiation doses of 0 kGy (native or control), 2.5 kGy and 5 kGy. Moisture, protein, fat, ash and carbohydrate content of native flour was found as 10 g/100 g, 6.54 g/100 g, 1.54 g/100 g, 1.0 g/100 g, and 81.48 g/100 g, respectively. The hunter color 'L', 'a', and 'b' values of the native brown rice flour sample were found as 81.95, -0.97 and 17.36, respectively and were non-significantly (p ≥ 0.05) affected by gamma irradiation. Apparent amylose content was observed to decrease significantly (p ≤ 0.05) from 29.97 to 20.30 g/100 g with the increase in gamma irradiation dose and moisture content. The pasting properties such as peak viscosity, trough viscosity and final viscosity of all the flour samples decreased significantly (p ≤ 0.05) with the increase in irradiation dose. The functional properties such as water and oil absorption and emulsion capacities were increased while emulsion stability and foaming stability decreased upon irradiation. Irradiation led to an overall increase in the antioxidant activity of rice flours. In general, FTIR spectra revealed a decrease in the absorption intensities of the functional groups. Therefore, it can be concluded that gamma irradiation can be used as a tool to modify the physicochemical properties of rice flours as well as to improve their antioxidant properties.

Influence of Gamma Irradiation and Water Aging on the Space Charge Characteristics of Epoxy Micro-Nano Composites.

Epoxy micro-nano composites are well-known to exhibit enhanced electrical, mechanical as well as thermal properties compared to base epoxy resin. Yet, a clear understanding need to be achieved on the long-term aging performance of the epoxy micro-nano composites. The present review article is a comprehensive study on the impact of gamma irradiation and water aging on the space charge characteristics of epoxy micro-nano composites that are applicable as insulant in high-voltage power apparatus. Ion-trapping nanoparticles, which possess good oxidation resistance and high ion trapping ability, are being chosen as nanofillers along with silica micro fillers in epoxy micro-nano composite material for improving the reliability of electrical insulation structures. The epoxy micro-nano composite specimens were subjected to gamma irradiation (4 kGy and 8 kGy) and water aging (under room temperature and at 90 °C), to analyze the effect of aging on space charge accumulation and charge decay characteristics. The mean magnitude of accumulated space charge density of epoxy micro-nano composites tends to increase with an increase in gamma irradiation dose as well as an increment in water diffusion coefficient. The mean lifetime of the space charge decay during depoling has significantly reduced after gamma irradiation and is converse with water aged specimen. Voltage polarity reversal studies have indicated that a part of homo-charge injected from electrodes remained as hetero-charge just after polarity reversal and could result in the distortion of electric field thereby increasing the electric field enhancement factor.

Study the induced-alterations by gamma irradiation in the compositional transformation, optical properties, surface morphology, and Vickers hardness of Makrofol TP 244

Gamma-rays with different doses ranging from 30 kGy to 450 kGy are used to induce suitable modifications of Makrofol TP-244. The induced changes are investigated using various procedures: FTIR, UV/Vis, Photoluminescence spectroscopy, SEM techniques, and roughness and Vickers micro-hardness testers. The FTIR spectra show aggregate variations in the band intensities after gamma irradiation, which indicate the scissioning and cross-linking of the polymer chains at particular gamma-doses. The UV/Vis spectra show that an induced change is detected in the absorbance edge after irradiation, which is associated with a decrease in the optical band gap energy. These changes indicate to the increase in the carbon clusters and increase in the opacity, which consequently improve the electrical conductivity of irradiated samples. The PL emission spectra indicate that the PL peak intensities reduce with the increase in gamma irradiation dose. The surface morphology and hardness measurements show an improvement in the sample surface after irradiation.

Determination the effect of gamma radiation on CR-39 detector by analysis of photoelasticity images using MATLAB software

The effect of gamma radiation on CR-39 detector was determinate through the image processing for the photoelasticity images by using of MATLAB software. The maximum change different in CR-39 detector colors at photoelasticity technique was appear at the value 2 kN as a mechanical compression effect. It was adopted this value of mechanical compression on CR-39 detector to calculation the change in color percentage -C% for four colors red, green, magenta and yellow. It was found the increase of gamma irradiation dose -D(Gy) on CR-39 detector at the range (100 to 600 Gy) lead to change in color percentage - C% for four colors. The polynomial equation for red color was a good smooth relation compared with polynomial equations for green, magenta, where the yellow color behavior as a logarithmic relation. The red color relation used to determination the effect of gamma radiation on CR-39 detector due to the clear behavior between D(Gy) with C%. In this study, we can consider that the image processing for the photoelasticity images of CR-39 detector by using of MATLAB software was a good method to calculate the effect of gamma radiation on CR-39 detector compared with other methods in this field.

The effect of gammairradiation for collagen in demineralized bone matrix particles with differences size

Objective To investigate the effects of different particle sizes on the collagen structure of demineralized bone matrix (DBM) and the effectiveness of dry ice as an irradiation protectant in the procedure of gamma irradiation. Methods DBM samples with different particle sizes (0.5-1.0 mm, 1.2-2.8 mm, 3.3-4.7 mm and 5.7-7.0 mm) were prepared, and sterilized with several doses of gamma irradiation (0 kGy, 15 kGy and 25 kGy) at room temperature. Additionally, another group of DBM samples were sterilized with 25 kGy gamma irradiation with protective agent. Changes in surface and characteristics of collagen were observed by using scanning electron microscope (SEM), Sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE), differential scanning calorimetry (DSC) and carbonyl content. Results The color of collagen extract indicated that oxidative damage is directly related to irradiation dose. SEM showed that the gamma irradiation caused collagen structure disorder and fiber breakage. As the irradiation doses increased, the damage area significantly increased. When the particle size increased, the damage area tended to decrease. The DSC showed that the thermal denaturation temperature of 5.7-7 mm, 3.3-4.7 mm, 1.2-2.8 mm and 0.5-1.0 mm were 142.8℃, 97.3℃,84.3℃ and 83.9℃, respectively. The differences of the thermal denaturation temperatures among the four particle sizes were statistically significant (F=0.560, P=0.650). Collagen structure was destroyed by gamma irradiation, resulting in a decrease in collagen molecular weight. While, large particle DBM had a tendency to resist radiation damage. There was a significant difference on the contents of carbonyl in collagen from same particle sizes of DBM with different irradiation dose. The carbonyl content gradually decreased with the increase of particle size, but the difference was not statistically significant (F=0.560, P=0.650). Conclusion The gamma irradiation and collagen oxidative damage have obvious dose-response relationship. With the increase of gamma irradiation dose, the degree of collagen damage increases. The sizes of DBM could affect the sensitivity of collagen to gamma irradiation. With the decrease of particle sizes, DBM particles are more susceptible to gamma irradiation damage. Additionally, dry ice, as a radiation protection agent, has a certain degree protection effect against radiation. Key words: Bone matrix; Collagen; Radiation; Gamma rays

Gamma dose dependent structural, optical and current-voltage characteristics of CdS/p-Si heterojunction

Heterojunction of CdS/p-Si were fabricated by deposited the cadmium sulfide (CdS) thin films on p-type silicon (Si) substrates using successive ionic layer adsorption and reaction (SILAR). To study the nano-structural, optical and current–voltage (I–V) characterization, the heterojunction was irradiated by gamma radiation with different dose in the range of 0–100 kGy. The X-ray diffraction results showed that CdS thin film has a nano-crystalline hexagonal structural with reduction in crystallinity. An increase in gamma irradiation dose the deposition temperature enhances crystallite sizes of CdS thin film. Field emission scanning electron microscope represented that the grain size was increased with increasing the gamma irradiation dose. The diffuse reflectance indicated that the CdS thin energy band gap shifted to lower energy as of function of gamma dose. The electrical parameters were calculated from the I–V characterization carried out in dark at room temperatures. From these measurements it is inferred that the forward current increases with increasing gamma dose whereas the turn on voltage drops from 4.38 V to 3.64 V. The ideality factor of the n-CdS/p-Si heterojunction is greater than unity, whereas the optimized values of series resistance, barrier height and saturation current for the CdS/p-Si changed with radiation because of density of defect induced by gamma and charge carrier trapping on interface layer.

X-ray diffraction and thermodynamics kinetics of SiB6 under gamma irradiation dose

The silicide hexaboride (B6Si) was irradiated with 60Co at room temperature to study the structural changes and weight kinetics. The B6Si samples were irradiated using a gamma source with a dose rate (D) of 0.27 Gy/s. At adsorption dose range of 9.7, 48.5, 97, 145.5 and 194 kGy. The samples were analysed using X-ray diffraction (XRD) and Energy dispersive spectroscopy (EDS) to study the microstructural and composition changes. The XRD results showed the crystalline structure for the sample before and after irradiation (with gamma irradiation dose 9.7, 48.5 and 97 kGy). Amorphization of the sample began at the gamma irradiation dose of 145.5 kGy. Increase in gamma irradiation dose had an inverse effect on the activation energy and had a directly proportional effect on the lattice volume.

Crystal structure changes and weight kinetics of silicon-hexaboride under gamma irradiation dose

Abstract The silicide hexaboride (B6Si) was irradiated with 60Co at room temperature to study the structural changes and weight kinetics. The B6Si samples were irradiated using a gamma source with a dose rate (D) of 0.27 Gy/s. At adsorption dose range of 9.7, 48.5, 97, 145.5 and 194 kGy. The samples were analysed using X-ray diffraction (XRD) and Energy dispersive spectroscopy (EDS) to study the microstructural and composition changes. The XRD results showed the crystalline structure for the sample before and after irradiation (with gamma irradiation dose 9.7, 48.5 and 97 kGy). Amorphization of the sample began at the gamma irradiation dose of 145.5 kGy. Increase in gamma irradiation dose had an inverse effect on the activation energy and had a directly proportional effect on the lattice volume.

Effect of gamma ray irradiation and ethyl methane sulphonate onin vitromutagenesis ofCitrullus colocynthis(L.) Schrad

In the present study in vitro mutagenesis was used to study the effect of gamma irradiation and EMS on callus induction, morphogenesis and production of multiple shoots from different explants of Citrullus colocynthis (L.) Schrad. Gamma radiations (5 kR to 20 kR) and certain chemicals have been effected on plant growth developments and changes of biochemical metabolisms in plants. Murashige and Skoog (MS) medium containing with auxins such as NAA, IAA, 2,4-D (0.5 ~ 2.0 mg/l), cytokinines BAP, kn TDZ, (0.5 ~ 2.5 mg/l), L-Glutamic acid (1 ~ 2 mg/l) and Coconut milk (10 ~ 20%). After 5 weeks on induction media, explants and callus (EC) were exposed to 5 kR, 10 kR, 15 kR and 20kR, of gamma radiation and treated with 1, 2, 3, 4 and 5 mM ethyl methane sulphonate (EMS) for 30 min. The highest percentage of callusing was observed (70%) stem irradiated with 5 kR and significantly decrease in fresh and dry weight of callus in the below 4 kR doses and above 20 kR doses, there was a progressive decrease in the fresh weight and dry weights when compared to control callus. Maximum percentage of plantlet regeneration (59%) was induced from callus exposed to 15 kR gamma irradiation on MS media fortified with 2.0 mg/l 2,4-D + 2.0 mg/l BAP + 2.0 mg/l L-glutamic acid. Increase in gamma irradiation dose above 15 kR and 5 mM EMS reduced regeneration capacity of callus. Doses higher than 20 kR and 7 mM EMS was lethal to micropropagated plants of Citurullus colocynthis.

Study of Gamma Irradiation Effect on Unplasticized PVC by Positron Annihilation

Positron annihilation technique is used to study the gamma irradiation effect on unplasticized PVC (UPVC). Positron annihilation lifetime spectroscopy (PALS) results show that both the o-Ps lifetime and intensity decrease with the increase of gamma irradiation dose. By comparing Coincidence Doppler Broadening (CDB) results of four typical polymers using different reference sample, it is confirmed that CDB ratio curve can truthfully reflect the momentum difference of electrons which positrons annihilate with. The CDB results of gamma-irradiated UPVC using non-irradiated UPVC rather than commonly chosen LDPE as a reference sample show obvious oxygen peak, together with FTIR results, verify the appearance of carbonyl groups around the free volume.

Synthesis of polyaniline films: case study on post gamma irradiation dose

The effect of gamma irradiation dose in the range of 1–10 kGy is investigated on the structural, optical and electrical properties of the polyaniline -emeraldine salt (PANI-ES) thin films deposited on the indium tin oxide (ITO) coated glass substrate by spin coating technique. X-ray diffraction patterns show that all deposited PANI films have an amorphous character. Fourier transform infrared spectroscopy (FTIR) confirms the emeraldine salt form of deposited PANI films. The analysis of UV–Vis spectrophotometer indicates a decrease of transmittance intensity and optical band gap with increase of gamma irradiation dose while Urbach energy increases. The photoluminescence (PL) spectra show a strong peak at 429 nm due to transition from polaron band to π band in PANI structure which its intensity and peak area increase with irradiation dose increase. Electrical measurement shows that the resistivity of prepared films linearly increases with rise of gamma dose suggesting its possible application as gamma dosimeter in the studied range.

Effects of low gamma irradiation dose on the photoluminescence properties of graphene quantum dots

We prepared graphene quantum dots (GQDs) using electrochemical approach. The luminescent properties of GQDs at various excitation wavelengths are examined. In order to study the possibility to improve these properties, we applied a low dose of gamma irradiation (15 kGy) on GQDs dissolved in two media: water and 4 % isopropyl alcohol solution. Upon gamma irradiation of water, various free radical species are formed and they usually cause oxidation. In the presence of isopropyl alcohol in water, during irradiation, oxygen contained radicals are quenched and only hydrogen radicals can survive and reduce the material exposed to irradiation. Morphology of GQDs is examined by atomic force and transmission electron microscopy. After gamma irradiation the increase of photoluminescence was noticed for both GQD samples. A higher intensity of photoluminescence is detected for GQDs irradiated in 4 % isopropyl alcohol solution. This result shows that further increase of gamma irradiation dose has a great potential for improvement of luminescence properties of GQDs.

Effect of gamma irradiation on structural and biological properties of a PLGA-PEG-hydroxyapatite composite.

Gamma irradiation is able to affect various structural and biological properties of biomaterials In this study, a composite of Hap/PLGA-PEG and their ingredients were submitted to gamma irradiation doses of 25 and 50 KGy. Various properties such as molecular weight (GPC), thermal behavior (DSC), wettability (contact angle), cell viability (MTT assay), and alkaline phosphatase activity were studied for the composites and each of their ingredients. The results showed a decrease in molecular weight of copolymer with no change in the glass transition and melting temperatures after gamma irradiation. In general gamma irradiation can increase the activation energy ΔH of the composites and their ingredients. While gamma irradiation had no effect on the wettability of copolymer samples, there was a significant decrease in contact angle of hydroxyapatite and composites with increase in gamma irradiation dose. This study showed an increase in biocompatibility of hydroxyapatite with gamma irradiation with no significant effect on cell viability in copolymer and composite samples. In spite of the fact that no change occurred in alkaline phosphatase activity of composite samples, results indicated a decrease in alkaline phosphatase activity in irradiated hydroxyapatites. These effects on the properties of PLGA-PEG-hydroxyapatite can enhance the composite application as a biomaterial.

Mutation Induced Genetic Variability in Rice (Oryza sativa L.)

Seeds of the Egyptian rice cultivar Sakha 105 were treated with three gamma radiation doses; 15, 20 and 25 Kr to study the effect of gamma irradiation doses in the process of mutation on the growth, yield and yield-related characters of sakha 105 rice cultivar as well as to induce genetic variability for selecting plants with desirable character. The effect of gamma -rays was observed in M1 and M2 generation for all the studied traits except panicle length in M1 and 1000-grain weight in both generations. The dose of 15 kr recorded the highest mean value of heading date and plant height in both generation and number of panicles/plant in M1 generation, this may be due to stimulatory effects of the low doses of gamma-rays which decrease with the increase of gamma irradiation dose. The dose of 20 Kr recorded significantly higher fertility percentage and number of branches/panicle in M2 generation and number of panicles/plant in M1 generation. The dose of 25Kr produced the highest number of panicles/plant and number of spikelets/panicle in M2 generation with in-significance difference with the control. While, it produced the lowest mean values for grain yield, number of filled grains/panicle, heading date and plant height in both generations. All the mutagenic treatments detected significantly lower grain yield than the un-treated plants in both generation. The measurements of variation were, in general, higher in the treated plants compared with the control. Such estimates were maximized in case of fertility percentage, number of filled grains/panicle and grain yield. Among all treatments, the dose of 25Kr gamma radiation detected the highest variation.

Effect of gamma irradiation on microbial load, aflatoxins and phytochemicals present in Trigonella foenum-graecum

The effects of gamma irradiation on microbial load, total aflatoxins and phytoconstituents content of Trigonella foenum-graecum have been studied. Gamma irradiation at a dose of 2.5 kGy resulted in 2 log reduction of the total aerobic microbial count. A complete sterilization was, however, observed at 10 kGy. The total aflatoxin level decreased gradually with increase in gamma irradiation dose as compared to its un-irradiated counterparts, whereas the high performance liquid chromatography (HPLC) profile showed no change in the levels of phytochemicals up to the gamma irradiation dose of 10 kGy. HPLC profiles, however, differed in peak areas, and retention times of the components. These results suggest that gamma irradiation at a dose of 5.0 kGy was very effective for microbial decontamination because it did not adversely affect the active components of T. foenum-graecum.

Effects of γ‐irradiation, storage and hydration on osteoinductivity of DBM and DBM/AM composite

This study investigated the effect of gamma-irradiation dose, irradiation temperature, hydration and storage condition on osteoinductivity of demineralized bone matrix (DBM) and demineralized bone matrix/acellular dermal matrix (DBM/AM) composite. DBM and DBM/AM in dry and hydrated form were treated with gamma-irradiation of 15-40 kGy at ambient or low temperature (-40 degrees C approximately -70 degrees C) and then stored at ambient condition for 6 months. The athymic rat muscle implant model was used to evaluate the osteoinductive potential of the DBM and DBM/AM composites. Histological and alkaline phosphatase (ALPase) activity assessments were carried out at 28 days after implantation to determine the new bone formation and ALPase activity. Both histological and ALPase activity analysis showed that the osteoinductivity of DBM decreased with the increase of gamma-irradiation dose at ambient temperature, whereas no decrease occurred when treated with gamma-irradiation at low temperature. However, the hydrated DBM showed diminishing osteoinductivity after 6-month storage at ambient condition, whereas the DBM in dry form retained their osteoinductivity after the 6-months storage. The findings in this study indicate that DBM and DBM/AM composites could retain their osteoinductivity when they are in dry configuration and are irradiated at low temperature (-40 degrees C approximately -70 degrees C) using the custom-made cold gamma-irradiation system.

Effects of various sterilization methods on the setting and mechanical properties of apatite cement.

Sterilization capability is a necessary requirement for any material that is to be used in a medical application. Therefore, it is necessary for apatite cement (AC) to be sterilized. Because there is little information on the sterilization methods of AC, the aims of this investigation were to evaluate the effects of various sterilization methods, including steam, dry heat, ethylene oxide (EtO) gas, and gamma irradiation sterilizations, on the setting and mechanical properties of AC. In the case of steam sterilization, because AC powder aggregated before setting-time measurements, the setting time could not be measured. When the powder was sterilized by dry heat or EtO gas, the setting time was prolonged significantly and the wet diametral tensile strength (DTS) value decreased significantly. Therefore, sterilizations with steam, dry heat, or EtO gas were suggested to be inappropriate methods for AC. Accordingly, the following experiments focused on gamma sterilization. The setting time of AC was retarded with an increase in gamma irradiation dose. The wet DTS value decreased with the increase in gamma irradiation dose. There was no compositional change due to the gamma irradiation. The following tests were carried out in order to examine the effect of the gamma irradiation on the setting reaction of AC in detail. Tetracalcium phosphate [TTCP: Ca(4)(PO(4))(2)O] and dicalcium phosphate anhydrous (DCPA: CaHPO(4)) were separately irradiated, and the cements were produced with the use of irradiated powder and nonirradiated powder. Although the wet DTS value of AC produced from irradiated TTCP and nonirradiated DCPA decreased with increasing gamma irradiation dose, there was no significant difference. In contrast, the wet DTS value of AC produced from irradiated DCPA and nonirradiated TTCP significantly decreased with the increase in gamma irradiation dose. In conclusion, although the detailed mechanism of the delayed setting time and decreased DTS value was not clarified by the present study, it was found that gamma irradiation affected DCPA more than TTCP.