Low-dose Gamma Irradiation Research Articles

Protective effects of curcumin against gamma ray induced conformational change of human serum albumin

This study explores the possibility for protection by curcumin during the molecular and structural changes of human serum albumin (HSA) exposed to gamma irradiation. We used a combination of spectroscopic methods to probe the conformational ensemble of the irradiated HSA and finally evaluated the extent of restoration by curcumin. SDS-PAGE study unfolded the formation of cross linked aggregates as a consequence of increasing exposure of gamma radiation. CD and FTIR spectroscopy indicated significant decrease in the alpha helix content of HSA from 57% to 15% with increasing radiation doses. Steady state and time resolved fluorescence studies complemented the spectroscopic measurements, when lifetime decay was significantly reduced from 6.35ns to 0.37ns. Hydrophobic study showed the effectiveness of curcumin for protection at low dose of gamma irradiated HSA samples. We integrated these observations to investigate protein aggregation under increasing gamma radiation and estimated the same in presence of curcumin. It was elucidated, that when HSA is irradiated at low dose of gamma radiation in presence of curcumin, it is capable of retaining the characteristic properties to a higher extent indicating stabilization of molecular structure of HSA by curcumin. A model for curcumin based protection has been proposed utilizing ThT assay.

The effect of low doses of gamma radiation on the electrophysical properties of mesoporous silicon

The effect of low exposure doses (5–40 kR) of gamma radiation on the electrical properties of structures based on a mesoporous silicon (SiMP) layer is investigated. It is demonstrated that the conductivity of the SiMP layer increases, the Fermi level shifts, and the trap density changes in gamma-irradiated Al/SiMP/p-Si/Al structures. Long-term stable switched-state memory in the region of the I–V curve hysteresis is revealed. This effect is controlled by the irradiation dose.

Effect of phytosanitary irradiation on the quality of two varieties of pummelos (Citrus maxima (Burm.) Merr.)

Phytosanitary treatments prevent the introduction of pests such as fruit flies into pest free zones, and are often required for international trade. Irradiation is increasingly being considered as an alternative to cold and chemical phytosanitary treatments, such as methyl bromide. In this study, the effect of low dose gamma irradiation on the post-harvest quality of two varieties of pummelos (Citrus maxima (Burm.) Merr.), an emerging crop of interest in the US was evaluated. Two varieties of pummelos grown in California were irradiated at the phytosanitary target dose of 150Gy and a higher dose of 1000Gy to exaggerate and hence confirm the effects of treatment. The fruit was stored at 12°C for 3 weeks and at 20°C for the 4th week to reflect three weeks of sea shipment at the ideal temperature for storage of pummelos and an additional week of retail under ambient conditions. Neither irradiation nor storage affected juice content, organic acids, sugars, peel or pulp color and consumer sensory preference, although numerous volatiles increased in concentration as a result of irradiation treatment. Irradiation caused an immediate reduction in whole fruit and pulp firmness in ‘Chandler’ but not ‘Sarawak’ pummelos at both 150Gy and 1000Gy. The quality of irradiated pummelos stored at refrigerated temperature for 3 weeks was similar to untreated pummelos, however, physical handling and exposure to higher temperature resulted in increased peel pitting of irradiated fruit compared to non-treated fruit. The results suggest that irradiation could serve as a potential phytosanitary treatment for Chandler and Sarawak pummelos, provided that the fruit is subjected to minimal handling and not temperature abused.

Regulated partitioning of fixed carbon (14C), sodium (Na+), potassium (K+) and glycine betaine determined salinity stress tolerance of gamma irradiated pigeonpea [Cajanus cajan (L.) Millsp

Soil salinity is a major constraint that limits legume productivity. Pigeonpea is a salt sensitive crop. Seed gamma irradiation at a very low dose (2.5Gy) is known to enhance seedling establishment, plant growth and yield of cereals and other crops. The present study conducted using two genetically diverse varieties of pigeonpea viz., Pusa-991 and Pusa-992 aimed at establishing the role of pre-sowing seed gamma irradiation at 0, 0.0025, 0.005, 0.01, 0.02, 0.05 and 0.1kGy on plant growth, seed yield and seed quality under salt stress at 0, 80 and 100mM NaCl (soil solution EC equivalent 1.92, 5.86 and 8.02dS/m, respectively) imposed right from the beginning of the experiment. Changes in carbon flow dynamics between shoot and root and concentration of osmolyte, glycine betaine, plant uptake and shoot and root partitioning of Na+ and K+ and activity of protein degrading enzyme protease were measured under the combined effect of gamma irradiation and salt stress. Positive affect of pre-sowing exposure of seed to low dose of gamma irradiation (<0.01kGy) under salt stress was evident in pigeonpea. Pigeonpea variety, Pusa-992 showed a better salt tolerance response than Pusa-991 and that the radiated plants performed better than the unirradiated plants even at increasing salinity level. Seed yield and seed protein and iron content were also positively affected by the low dose gamma irradiation under NaCl stress. Multiple factors interacted to determine physiological salt tolerance response of pigeonpea varieties. Gamma irradiation caused a favourable alteration in the source-sink (shoot-root) partitioning of recently fixed carbon (14C) under salt stress in pigeonpea. Gamma irradiation of seeds prior to sowing enhanced glycine betaine content and reduced protease activity at 60-day stage under various salt stress regimes. Lower partitioning of Na+and relatively higher accumulation of K+ under irradiation treatment was the other important determinants that differentiated between salt-tolerant and salt-susceptible variety of pigeonpea. The study provides evidence and physiological basis for exploring exploitation of pre-sowing exposure of seeds with low-dose gamma ray for enhancing the salt tolerance response of crop plants.

Metformin and low dose radiation modulates cisplatin-induced oxidative injury in rat via PPAR-γ and MAPK pathways

Cisplatin (CIS) is a chemotherapeutic agent used for therapy of many tumors and has been limited by its toxicity. The aim of this study was to investigate the role of Peroxisome proliferator–activated receptor-gamma (PPAR-γ), mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B(NFkB) in the pathogenesis of hepatic damage induced by CIS, and investigated the modulatory effect of metformin (MET) and/or low dose gamma radiation (LDR) on CIS-induced hepatotoxicity in rats. CIS(7.5 mg/kg, i.p.) hepatotoxicity was evidenced by alteration of serum hepatic indices (ALT and AST) accompanied with decreased hepatic PPAR-γ, superoxide dismutase (SOD) activities and reduced glutathione (GSH) content, whereas the levels of malondialdehyde (MDA), total nitrate/nitrite (NOx) and NFkB significantly increased as well as MAPK activity compared with the control, MET and LDR groups. Furthermore, CIS induces apoptosis as indicated by an elevation of hepatic caspase-3. Treatment with MET (150 mg/kg, orally for 14 days) and/or LDR (0.5 Gy), prior to CIS alleviates CIS-induced hepatic damage by mitigating oxidative/ nitrosative stress and PPAR-γ activity reduction, hepatic caspase-3 elevation, and inhibition of NFκB, and MAPK activity levels. Conclusions: Modulation of PPAR-γ, MAPK and NFkB might contribute to amelioration of CIS-induced hepatic toxicity.

Exposure of luminous marine bacteria to low-dose gamma-radiation

The study addresses biological effects of low-dose gamma-radiation. Radioactive 137Cs-containing particles were used as model sources of gamma-radiation. Luminous marine bacterium Photobacterium phosphoreum was used as a bioassay with the bioluminescent intensity as the physiological parameter tested. To investigate the sensitivity of the bacteria to the low-dose gamma-radiation exposure (≤250 mGy), the irradiation conditions were varied as follows: bioluminescence intensity was measured at 5, 10, and 20°С for 175, 100, and 47 h, respectively, at different dose rates (up to 4100 μGy/h). There was no noticeable effect of gamma-radiation at 5 and 10°С, while the 20°С exposure revealed authentic bioluminescence inhibition. The 20°С results of gamma-radiation exposure were compared to those for low-dose alpha- and beta-radiation exposures studied previously under comparable experimental conditions. In contrast to ionizing radiation of alpha and beta types, gamma-emission did not initiate bacterial bioluminescence activation (adaptive response). As with alpha- and beta-radiation, gamma-emission did not demonstrate monotonic dose-effect dependencies; the bioluminescence inhibition efficiency was found to be related to the exposure time, while no dose rate dependence was found. The sequence analysis of 16S ribosomal RNA gene did not reveal a mutagenic effect of low-dose gamma radiation. The exposure time that caused 50% bioluminescence inhibition was suggested as a test parameter for radiotoxicity evaluation under conditions of chronic low-dose gamma irradiation.

Evidences for amelioration of reserpine-induced fibromyalgia in rat by low dose of gamma irradiation and duloxetine

Objective: Fibromyalgia is a prevalent disorder characterized by chronic widespread pain and complex symptoms. This study was conducted to investigate the potential therapeutic effect of low-dose irradiation (LDI) alone or in combination with duloxetine on the reserpine-induced fibromyalgia in rats.Methods: Fibromyalgia was induced by administration of reserpine (1 mg/kg/s.c) for 3 consecutive days. Duloxetine (30 mg/kg, p.o) was administered 60 min before a forced swimming test (FST), and rats were exposed to a single dose of γ-radiation (0.5 Gy) 1 day before the FST.Results: Reserpine significantly increased immobility time in the FST, decreased the amount of 5-hydroxytryptamine, dopamine, and norepinephrine in cerebral cortex. It also increased malondialdehyde and nitric oxide and reduced glutathione contents in brain tissue. LDI alone or combined with duloxetine completely antagonized reserpine-induced fibromyalgia as assessed by the measured parameters. One of the most significant findings in this study was that the therapeutic effect of duloxetine was more pronounced by its combination with LDI. A possible mechanism of action of LDI and duloxetine responsible for their therapeutic effect was discussed.Conclusion: On the basis of the presented evidences, it could be concluded that LDI alone or combined with duloxetine could be of value in the management of fibromyalgia.

Effect of gamma irradiation on cyto-morphology, total phenolic content and antioxidant activity of calendula

Gamma ray irradiation is one of the best ways to induce mutation and increase genetic variability in plants. The present investigation was carried out to study the effect of gamma irradiation on cyto-morphological and phytochemical attributes in Calendula officinalis Linn and screening of novel mutants. The seeds of Calendula officinalis var. Fiesta Gitana Yellow were exposed to gamma rays (20, 40, 60, 80, 100, 120 and 140 Gy) treatment using 60Co source, and un-irradiated seeds were used as control. Low doses of gamma irradiation resulted in hormesis and induced encouraging novelties, while the higher doses induced higher degree of abnormalities, which even led to mortality in many plants. In M1 generation, 10 mutants were screened and tagged, of which three promising mutants viz. C1 and C2 at 20 Gy and C3 at 40 Gy gamma irradiation, were found stable till M2 generation. They were screened for cytomorphological studies, phytochemical attributes (total phenolic content and antioxidant activity) and possible use of these novel traits (flower colour and plant height) as ornamental novelties, which can be released as a new variety after subsequent studies in further generations.

Effect of Gamma Ray on Reactive Oxygen Species at Experimental Animals

The present study was designed to investigate the oxidative stress, which is due to the effect of low doses of gamma irradiation. Animals were divided into 6 groups, where the first group kept as control group, while 2nd, 3rd, 4th, 5th and 6th groups were exposed to gamma ray at 1.5 Gy, 2 Gy, 2.5 Gy, 3 Gy and 3.5 Gy once weekly for one month respectively. Rats were subjected to gamma radiation and nitric oxides (NO), superoxide dismutase (SOD), malondialdehyde, alanine aminotransferase (ALT), aspartate aminotransferase (AST) and white blood cells (WBCs) were measured. SOD recorded highly significant decrease with percent change -22.7%, -25.01%, -55.01% -55.4% and -56.38% respectively in groups which were exposed to 1.5, 2, 2.5, 3 and 3.5 Gy. MDA serum level have a significant increase in groups which were exposed to successive doses of 1.5 Gy, 2 Gy, 2.5 Gy, 3 Gy and 3.5 Gy respectively with percent change 25.7% , 41.8% 59.1% 65.6% 75.8% consequently as compared to control group. Nitric oxide serum level is markedly showed highly significant increase in rats exposed to successive dose of 1.5, Gy, 2 Gy, 2.5 Gy, 3 Gy and 3.5 Gy respectively with percent change 59.69%, 74.17%, 87.1%, 120.1% and 130.6% consequently as compared to control group. ALT and AST recorded highly significant increase in rats exposure to successive doses of 1.5, Gy, 2 Gy, 2.5 Gy, 3 Gy and 3.5 Gy respectively. On the other hand WBCs recorded highly significant decreased in rats exposed to successive dose of 1.5, Gy, 2 Gy, 2.5 Gy, 3 Gy and 3.5 Gy respectively. WBCs recorded percent change -26.11%, -32.3%, -47.8%, -50.1% and -53.6% respectively as compared to control group.

Variability induction in Ox-eye daisy (Leucanthemum vulgare Lam.) using gamma rays

The present investigation was aimed to study hormesis, morphological and biochemical variability attributes associated with mutation and purification of novel mutants in Ox-eye daisy. The seeds of Leucanthemum vulgare were exposed to 20, 40, 60, 80 and 100 Gy doses of gamma rays (source 60Co). These irradiated seeds were used to raise seedlings and planted in combination with seedlings from non-irradiated seeds (control) in randomized block design. Low doses of gamma irradiation resulted in hormesis and evoked encouraging novelties, whereas, the higher doses elicited higher degree of abnormalities and consequently mortality. The M2 seeds were seeded to observe new characters and mutations in population in every treatment. The minimum plant survival was 51.60% at 100 Gy gamma rays treatment, which significantly differed from all other treatments. The maximum plant survival (99.67%) was observed in non-irradiated control. It was observed that plant survival significantly declined with the increase in the dose of gamma irradiation. Plants raised from irradiated seeds showed significant delay in flowering over the control. The earliest blooms were observed in control (108.03 days), while the maximum days to bloom (118.30 days) were recorded with 100 Gy treatment. Three promising mutants, viz., Spatulate type (L1) at 40 Gy, Quilled-spatulate type (L2) at 60 Gy and Quilled type (L3) at 60 Gy gamma irradiation treatment were labelled, screened and checked for stability of characters in M2 and M3 generations. The seeds of M2 and M3 generations were raised for observation for variation in morphological characters and stability mutants in every generation.

Effects of Gamma Irradiation on AlGaN-Based High Electron Mobility Transistors

The influence of various radiations on the performance and carrier transport properties of AlGaN/GaN HEMTs have been observed at length over the previous few decades. Gamma irradiation has been shown to have little influence on carrier density but has significant effects on device performance. The effects of gamma irradiation have proven non-monotonic in nature, dividing results into low and high doses with an inflection point near 300 Gy. Low doses of gamma irradiation have a tendency to improve device characteristics, while high doses lead to device degradation. The differences in low versus high doses are highlighted by electron beam induced current and dc characterizations. The variance in behavior originates from irradiation-induced trap generation and subsequent trap occupation from Compton scattering. AlGaN/GaN-based HEMTs have shown carrier transport enhancement for low doses.

Gamma Irradiation-Induced Variation in Dendrobium Sonia-28 OrchidProtocorm-Like Bodies (PLBs)

Dendrobium sonia-28 is an important ornamental orchid in the flower industry. In vitro mutagenesis by means of gamma irradiation can be used to produce economically improved mutants. Protocorm-like bodies (PLBs) of Dendrobium sonia-28 were subjected to gamma irradiation at doses of 10 to 200 Gy gamma rays. Results showed that PLBs survival rate and weight were inversely related to the irradiation doses. In untreated PLBs, survival rate and weight were tenfold and fivefold higher as compared to 200 irradiated PLBs. Results indicated that the radio sensitivity test (LD50) for the PLBs were approximately at 43 Gy. There were appreciable variations in plantlet structure and morphology relative to increase irradiation doses. Plantlets infected with low doses of gamma radiation had better development of the shoot and root as well as the foliage. SEM and TEM analysis disclosed severe surface and cell organelles damage and stomatal closure in protocorm-like bodies (PLBs) infected with the high irradiation dose. Therefore, the findings of this study have proven an efficient method of in vitro mutagenesis through gamma radiation. The results obtained in this study suggested that PLBs survival rate, growth rate percentage, morphological characteristics as well as techniques such as SEM and TEM may be used in early assessment of effectiveness and superiority of radiation dose to induce mutations. Moreover, Some RAPD markers clearly discriminated between selected and non-selected variants of Dendrobium sonia-28, showing different banding patterns for each gamma irradiation doses.

Biochemical Changes Induced by Gamma Irradiation in the Ground Beetle Blaps polycresta

The exposure to low-dose gamma radiation from natural sources is a continuing and inescapable feature and it is common in certain occupations. The present study was designed to investigate the effects of low-dose gamma radiation on some detoxification enzymes such as; AST, ALT, ACP, ALP, GSH, GPX, SOD and CAT, as well as, its effect on total protein and DNA content in the soft tissues homogenate of male’s ground beetle Blaps polycresta. Insects were divided into three groups (group A, B and C) of 10 beetles each. Two groups (group B and C) were irradiated with doses at a rate of 32 Gy and 64 Gy; group A was considered as the control group. The study revealed a dose-dependent effect on the tested parameters. Significant increase in the enzyme activity of AST, ALT, ACP and ALP were observed in group B and C respectively compared to the control group (group A). The findings also showed a significant inhibitions in the enzymatic activity of GSH, GST, GPX, SOD and CAT in the irradiated groups compared to the control group. Furthermore, their radiated groups reported a decrease in protein and DNA content compared to the control group. Our observations suggested that the genotoxic effects of gamma radiation induced damaging effects on enzyme molecules, protein and nucleic acid (DNA) and may explain the increase in health risk from high doses of ionizing radiation.

Influence of low dose of gamma radiation and storage on some vitamins and mineral elements of dried oyster mushrooms (Pleurotus ostreatus).

Mushrooms contain some of the most potent natural medicines on the planet. Vitamins A, C, D, Mineral elements, contents, as well as total soluble solids (Brixo) of dried composition of Pleurotus ostreatus were investigated after exposing to gamma radiation doses of 0 (control), 0.5, 1, 1.5, and 2 kGy at a dose rate of 1.7 kGy per hour in air from a Cobalt 60 source (SLL 515, Hungary) batch irradiator prior to storage (0 month) and after storage (12 months) at room temperature (28 ± 2°C). Results obtained showed some significant (p < .05) differences due to irradiation and storage. Before storage, vitamins A, C, and D contents of dried and irradiated mushrooms ranged 0.003 ± 0.08–0.014 ± 0.08, 0.042 ± 1.06–0.132 ± 1.06, and 0.040 ± 0.76–0.057 ± 0.76 mg/g, respectively. After 12 months, vitamin contents decreased and ranged 0.0029 ± 0.08–0.010 ± 0.08, 0.038 ± 1.06–0.125 ± 1.06, and 0.031 ± 0.76–0.05 ± 0.76 mg/g for vitamins A, C, and D, respectively. Total soluble solids recorded 1.5 Brixo, however, showed no significant difference (p > .05) and did not change in 12 months after gamma irradiation up to 2 kGy. Sodium ranged from 14.00 ± 0.7 to 14.90 ± 0.8 mg/100 g. Potassium content varied from 30.20 ± 0.5 to 33.10 ± 0.6 mg/100 g. Magnesium content ranged 1.27 ± 0.15–3.53 ± 0.04 mg/100 g. Calcium ranged 11.00 ± 0.4–12.53 ± 0.4 ± 0.03 mg/100 g. Phosphorus content ranged 6.11 ± 0.30–6.41 ± 0.35 mg/100 g, whereas Nitrogen content was found to be 3.00 ± 0.03–3.60 ± 0.25 mg/100 g. Microelements or heavy metals included Copper; detected ranged 0.00 ± 0.00–0.02 ± 0.001 mg/100 g, Zinc content ranged 0.01 ± 0.002–0.03 ± 0.001 mg/100 g. Iron content was found to be in the range 0.29 ± 0.01–0.37 ± 0.1 mg/100 g. Manganese content was found to be in the range 0.03 ± 0.001–0.04 ± 0.01 mg/100 g. Lead content was found to be 0.00 ± 0.00–0.03 ± 0.001 mg/100 g. Food processing and storage has the potential to slightly alter the stability of vitamins in foods. Pleurotus ostreatus showed appreciable levels of mineral elemental composition, essential vitamins A, C, and D, and can be endorsed as a natural medicinal food product in the food and pharmaceutical industries. The heavy metals detected were with also below the upper limits permissible by the WHO standards and is thus safe for human consumption.

Anti-apoptotic and antioxidant effects of low dose gamma irradiation against diabetes-induced brain injury in rats.

The current study aimed to investigate the effect of different low doses of gamma irradiation on hyperglycemia-induced brain injury. The aim was further extended to investigate the sub-chronic effect of low dose radiation on the neuronal damage induced by diabetes. To induce diabetes, male albino rats were injected with dexamethasone (10mg/kg/day, for 9 successive days, subcutaneously). Different diabetic groups were irradiated with 0.1, 0.25 and 0.5Gy. The effect of low dose gamma irradiation on the hyperglycemia-induced brain damage based was analyzed at two levels: oxidative stress and apoptosis. The brain contents of glutathione, malondialdhyde and total nitrate/nitrite were measured to assess the oxidative stress. In order to evaluate the extent of the apoptotic changes in brain, tissue caspase-3 expression was detected using immunohistochemistry and the degree of DNA fragmentation was estimated. Moreover, brain tissues were examined using light microscopy to evaluate the histological changes in different groups and serum lactate dehydrogenase activity was determined as an indicator for the brain tissue damage. Results indicated that exposure to 0.5Gy ameliorated the hyperglycemia and subsequently inhibited oxidative stress and apoptosis. Radiation exposure at this dose level also increased the survival rate of diabetic animals.

Effects of low-doses ionizing radiation on IL-4, IFN-γ and TGF-β genes expression in spleen lymphocytes of BALB/C mice

Introduction While the widespread application of ionizing radiation in diagnostic and therapeutic medical procedures is unavoidable, Effects of low doses of ionizing radiation LDIR (low doses of ionizing radiation) are not quite obvious. Moreover, it has been showed that LDIR could affect our immune system. Purpose The aim of this study was to appraise the effects of LDIR on the inflammation genes expression levels of the immune system. Materials and Methods Balb/C mice were exposed to 20, 50 and 100 mGy WBI by gamma rays from a Cobalt-60 source. Lymphocytes of their spleen were extracted 24 h after exposing the animal for gene expression analysis. IL-4, IFN- γ and TGF- β expression levels were examined by relative quantitative real-time PCR and IFN- γ /IL-4 ratio was evaluated. To compare means values of gene expression the independent samples T-test was performed. Results The results of this study are evident that low doses of gamma radiation can induce changes on the expression level of the investigated genes and IFN-/IL-4 ratio in Balb/C spleen lymphocytes. A significant reduction of IL-4, IFN- γ and TGF- β genes and an increase of IFN- γ /IL-4 ratio has been induced in the group with 20 mGy of LDIR, while IFN- γ /IL-4 ratio was not changed following to 50 and 100 mGy of gamma irradiation. Conclusion Our result revealed that 20 mGy dose of gamma radiation can activate protection mechanisms as apoptosis and therefore cause the reduction of investigated genes and immune response shifting to Th1 and thereupon humoral immunity. However no shift to immune response has been observed in the groups which have received doses of 50 and 100 mGy. These results may be of importance to radiation workers and autoimmune patients. Disclosure There is not any relationship that might lead to a conflict of interest. Mashhad University of Medical Sciences (MUMS) has financially supported this work.

Mechanical Properties of Gamma Irradiated Versus Non-Gamma Irradiated Dense Cancellous Bone

Category: Basic Sciences/Biologics Introduction/Purpose: Allograft bone is used for a myriad of purposes in the foot and ankle, not limited to: restoring bone length at an arthrodesis site, correction of an angular deformity or filling a bone defect. The processing techniques between tissue banks vary and may include gamma irradiation, use of hydrogen peroxide, ethylene oxide, or strict aseptic processing of allograft bone. The purpose of this pilot study is to determine if using gamma irradiation during processing will significantly decrease the modulus, maximum compression strain and stress and energy during static testing of dense cancellous bone. The purpose is to also determine if using gamma irradiation during processing will significantly decrease the strain energy of the allograft during dynamic testing in dense cancellous bone. Methods: Cylinders of bone were harvested from cadaveric male specimens age 18-55 with no history of skeletal disease, abnormality or trauma to the lower extremities. Bone cylinders were harvested from the femoral head, femoral condyle and proximal tibia and were separated into right and left. All right bone cylinder specimens were processed aseptically. All left bone cylinder specimens were processed using low-dose gamma irradiation (12.7-13 kGy). Following processing, 36 bone cylinder specimens underwent static testing of right (N=18, aseptic processing) versus left (N=18, low-dose gamma irradiated) in equal amounts to determine modulus, maximum compression stress and strain and energy. 36 bone cylinders underwent dynamic testing of right (N=18, aseptic processing) versus left (N=18, low dose gamma irradiated) for strain energy. Results: Static testing results demonstrated a 27% reduction in modulus (p=.18), a 26% reduction in maximum stress (p=.20), a 15% reduction in strain at maximum stress and a 37% reduction in energy (p=0.05) in the gamma irradiated specimens versus aseptically processed specimens. Energy is the area under a stress strain curve and represents the ability of a material to resist impact. Dynamic testing results include a 36% reduction in cumulative energy in gamma irradiated specimens versus aseptically processed specimens at the 1000th cycle (p=0.02), a 37% reduction at the 2500th cycle (p=0.03), and a 39% reduction at the 5000th cycle (p=0.05). Six samples in the irradiated group failed before 10,000 cycles and one sample in the aseptic group failed before 10,000 cycles. Conclusion: This pilot study confirms previous studies using cortical bone that gamma irradiation degrades the structural properties of cancellous allograft bone. Statistically significant differences in cumulative energy absorption were observed between treatment groups during dynamic testing. Energy absorption decreased by 36-39% in the gamma irradiated group. Differences in the average between the two treatment groups were observed for all static material properties, though not statistically significant: modulus, maximum stress, strain at maximum stress and energy. The most drastic difference was observed in energy, which represents the ability of allograft to plastically deform without fracturing or failing.

Effect of gamma irradiation on Schottky-contacted vertically aligned ZnO nanorod-based hydrogen sensor

We report the impact of gamma irradiation on the performance of a gold Schottky-contacted ZnO nanorod-based hydrogen sensor. RF-sputtered vertically aligned highly c-axis-oriented ZnO NRs were grown on Si(100) substrate. X-ray diffraction shows no significant change in crystal structure at low gamma doses from 1 to 5 kGy. As gamma irradiation doses increase to 10 kGy, the single crystalline ZnO structure converts to polycrystalline. The photoluminescence spectra also shows suppression of the near-band emission peak and the huge wide-band spectrum indicates the generation of structural defects at high gamma doses. At 1 kGy, the hydrogen sensor response was enhanced from 67% to 77% for 1% hydrogen in pure argon at a 150 °C operating temperature. However, at 10 kGy, the relative response decreases to 33.5%. High gamma irradiation causes displacement damage and defects in ZnO NRs, and as a result, degrades the sensor’s performance as a result. Low gamma irradiation doses activate the ZnO NR surface through ionization, which enhances the sensor performance. The relative response of the hydrogen sensor was enhanced by ∼14.9% with respect to pristine ZnO using 1 kGy gamma ray treatment.

The effect of Ginkgo biloba against ferric nitrilotriacetate and/or low doses of gamma irradiation induced renal injury in rats

The effect of Ginkgo biloba against ferric nitrilotriacetate and/or low doses of gamma irradiation induced renal injury in rats

Potential of carboxymethyl cellulose coating and low dose gamma irradiation to maintain storage quality, inhibit fungal growth and extend shelf-life of cherry fruit.

Carboxymethyl cellulose (CMC) coatings alone and in combination with gamma irradiation was tested for maintaining the storage quality, inhibiting fungal incidence and extending shelf-life of cherry fruit. Two commercial cherry varieties viz. Misri and Double after harvest at commercial maturity were coated with CMC at levels 0.5-1.0% w/v and gamma irradiated at 1.2kGy. The treated fruit including control was stored under ambient (temperature 25±2°C, RH 70%) and refrigerated (temperature 3±1°C, RH 80%) conditions for evaluation of various physico-chemical parameters. Fruits were evaluated after every 3 and 7days under ambient and refrigerated conditions. CMC coating alone at levels 0.5 and 0.75% w/v was not found effective with respect to mold growth inhibition under either of the two conditions. Individual treatment of CMC coating at 1.0% w/v and 1.2kGy irradiation proved helpful in delaying the onset of mold growth up to 5 and 8days of ambient storage. During post-refrigerated storage at 25±2°C, RH 70%, irradiation alone at 1.2kGy gave further 4days extension in shelf-life of cherry varieties following 28days of refrigeration. All combinatory treatments of CMC coating and irradiation proved beneficial in maintaining the storage quality as well as delaying the decaying of cherry fruit during post-refrigerated storage at 25±2°C, RH 70% but, combination of CMC at 1.0% w/v and 1.2kGy irradiation was found significantly (p≤0.05) superior to all other treatments in maintaining the storage quality and delaying the decaying of cherry fruit. The above combinatory treatment besides maintaining storage quality resulted in extension of 6days in shelf life of cherry varieties during post-refrigerated storage at 25±2°C, RH 80% following 28days of refrigeration. Above Combination treatment gave a maximum of 2.3 and 1.5 log reduction in yeast and mold count of cherry fruits after 9 and 28days of ambient and refrigerated storage, thereby ensuring consumer safety.