Non-irradiated Samples Research Articles

Effects of low-energy electron beam irradiation on the shelf-life and quality of vacuum-packaged beef steaks during chilled storage

This study evaluated the effects of different doses (0, 4, 8, 12, 16 kGy) of low-energy electron beam (LEEB; 0.2 MeV) on the quality changes of vacuum-packaged beef steaks during chilled storage for 21 days. LEEB irradiation at a low dose (4 and 8 kGy) significantly elevated the L* values of steaks, and did not deteriorate the a* values, the oxidation of lipid and protein (P > 0.05) compared to non-irradiated samples. LEEB irradiation (4 and 8 kGy) also significantly reduced the bacterial loads compared with non-irradiated steak, which may be due to the inactivation effect on Acinetobacter, Brochothrix thermosphacta, Carnobacterium divergens, Leuconostoc and Serratia during storage. Albeit all doses retained more acceptable sensory characteristics compared to non-irradiated samples, LEEB irradiation with >8 kGy significantly reduced the L* values and promoted protein oxidation. Overall, the LEEB irradiation with 4–8 kGy could be used as a promising innovative technology for extending the shelf-life of vacuum-packaged chilled beef steaks.

Alexandrite: investigation of a natural material for radiation dosimetry

In this work we performed experimental analyses of the dose-response curves of natural alexandrite, using thermoluminescence (TL) and optically stimulated luminescence (OSL). The natural alexandrite crystals from Bahia, Brazil, were pulverized and the optical absorption measurements were carried out in the range of 200 to 800 nm, comparing a non-irradiated sample with a 10 Gy beta irradiated one. OSL and TL measurements were performed using the Risø equipment (model DA-20) with irradiation doses from 1 to 5 Gy. Glow curve analysis was done using GlowFit software for TL, and R Studio software for OSL measurements. The irradiated sample (10 Gy) shows an absorption spectrum similar to the non-irradiated one, containing the same bands. The samples of natural alexandrite showed a linear dose-response for both OSL and TL measurements. From the TL and OSL analyses, it was possible to infer a correlation between the slow OSL component with the most intense TL peaks of alexandrite.

Stability Study of the Irradiated Poly(lactic acid)/Styrene Isoprene Styrene Reinforced with Silica Nanoparticles.

In this paper, the stability improvement of poly(lactic acid) (PLA)/styrene-isoprene block copolymer (SIS) loaded with silica nanoparticles is characterized. The protection efficiency in the material of thermal stability is mainly studied by means of high accurate isothermal and nonisothermal chemiluminescence procedures. The oxidation induction times obtained in the isothermal CL determinations increase from 45 min to 312 min as the polymer is free of silica or the filler loading is about 10%, respectively. The nonisothermal measurements reveal the values of onset oxidation temperatures with about 15% when the concentration of SiO2 particles is enhanced from none to 10%. The curing assay and Charlesby–Pinner representation as well as the modifications that occurred in the FTIR carbonyl band at 1745 cm−1 are appropriate proofs for the delay of oxidation in hybrid samples. The improved efficiency of silica during the accelerated degradation of PLA/SIS 30/n-SiO2 composites is demonstrated by means of the increased values of activation energy in correlation with the augmentation of silica loading. While the pristine material is modified by the addition of 10% silica nanoparticles, the activation energy grows from 55 kJ mol−1 to 74 kJ mol−1 for nonirradiated samples and from 47 kJ mol−1 to 76 kJ mol−1 for γ-processed material at 25 kGy. The stabilizer features are associated with silica nanoparticles due to the protection of fragments generated by the scission of hydrocarbon structure of SIS, the minor component, whose degradation fragments are early converted into hydroperoxides rather than influencing depolymerization in the PLA phase. The reduction of the transmission values concerning the growing reinforcement is evidence of the capacity of SiO2 to minimize the changes in polymers subjected to high energy sterilization. The silica loading of 10 wt% may be considered a proper solution for attaining an extended lifespan under the accelerated degradation caused by the intense transfer of energy, such as radiation processing on the polymer hybrid.

Evaluation an Aqueous Extract of Irradiated and Non Irradiated of Orthosiphon Aristatus on Zebrafish Embryo (Danio Rerio) through Acute Toxicity Assay

Background: Orthosiphon aristatus has been usually related to be powerful in curing many illnesses inclusive of post-partum remedy, anti-influence, rheumatism and stopping osteoporosis as a result of menopause. Objectives: Thus, this study was designed to differentiate the toxicity effect of non-irradiated and irradiated Orthosiphon aristatus at different dosage of 3, 6, 9 and 12 kilogray (kGy) on zebrafish embryo. Method: Survival rate, hatching rate, heart beat rate and scoliosis were observed and date were analysed using SPSS 25.00 windows. Result: The lethal dose (LC50) of non-irradiated Orthosiphon aristatus is 381.81 μg/mL compare to irradiated extract at 3 % is (371.27 μg/mL), 6 % (311.03 μg/mL), 9 % (160.72 μg/mL) and 12 % (140.18 μg/mL). Hatchability of zebrafish embryo for Orthosiphon aristatus extract decrease in the higher dosage of irradiated sample compared to non-irradiated sample. No presence of scoliosis was observed in all dosage of irradiated and non-irradiated of Orthosiphon aristatus. The heartbeat of zebrafish embryo treated with irradiated Orthosiphon aristatus specifically 12 % show decrease at 250 μg/mL concentration. Remaining dosage of irradiated and non-irradiated Orthosiphon aristatus show average heartbeat around 120 - 160 bpm. Conclusion: As conclusion, irradiated and non-irradiated of Orthosiphon aristatus is safe to be consumed due to its pharmaceutical effect but it still exhibited mild toxicity effect on zebrafish embryo. 
 HIGHLIGHTS
 
 Herbal medicine (Orthosiphon aristatus) is widely used for treatment as alternative medicine
 This Orthosiphon aristatus easy can be contaminated by bacteria and fungus. Gamma ray is helpful to eliminated the bacteria and fungus
 Irradiated Orthosiphon aristatus can be toxic due to the exposure in Gamma ray
 Toxicity study using zebra fish show no changes in toxicity of Orthosiphon aristatus
 
 GRAPHICAL ABSTRACT

Detection of Low Dose-Gamma Irradiated Spices by Photostimulated Luminescence (PSL) Technique

Photostimulated Luminescence (PSL) has been widely used as a rapid screening technique for the detection of various irradiated foods. This study aims to investigate the efficacy of the PSL technique in the detection of low dose-gamma irradiated spices available in the Malaysia market. Samples of clove, coriander, fenugreek, turmeric powder and curry powder were irradiated at very low doses; 0 (control), 0.2, 0.5 and 1 kGy using Cobalt-60 as a source. PSL measurements and analysis were undertaken under subdued lighting following EN 13751 methods. The PSL value in the form of photon counts (PCs/60s) of all samples as a function of the irradiation dose after 7 days of storage were determined which revealed that the PSL value increases proportionally to the radiation dose applied. The PSL also was able to discriminate between the non-irradiated (<700 PCs/60s, negative) and irradiated (>5000 PCs/60s, positive) samples after 7 days of storage. Coriander generates the highest PCs at the lowest dose (0.2 kGy) and highest dose (1 kGy) after that storage period. The PSL value of all spice samples is considered accurate and consistent at all irradiation doses. This technique is highly reliable for the detection of irradiated spices available in the Malaysia market.

Electron Beam Radiation as a Safe Method for the Sterilization of Aceclofenac and Diclofenac—The Usefulness of EPR and 1H-NMR Methods in Determination of Molecular Structure and Dynamics

Diclofenac (DC) [2-(2,6-Dichloroanilino)phenyl]acetic acid,) and aceclofenac (AC) 2-[2-[2-[(2,6-dichlorophenyl)amino]phenyl]acetyl]oxyacetic acid in substantia were subjected to ionizing radiation in the form of a beam of high-energy electrons from an accelerator in a standard sterilization dose of 25 kGy and higher radiation doses (50–400 kGy). We characterized non-irradiated and irradiated samples of DC and AC by using the following methods: organoleptic analysis (color, form), spectroscopic (IR, NMR, EPR), chromatographic (HPLC), and others (microscopic analysis, capillary melting point measurement, differential scanning calorimetry (DSC)). It was found that a absorbed dose of 50 kGy causes a change in the color of AC and DC from white to cream-like, which deepens with increasing radiation dose. No significant changes in the FT-IR spectra were observed, while no additional peaks were observed in the chromatograms, indicating emerging radio-degradation products (25 kGy). The melting point determined by the capillary method was 153.0 °C for AC and 291.0 °C for DC. After irradiation with the dose of 25 kGy for AC, it did not change, for DC it decreased by 0.5 °C, while for the dose of 400 kGy it was 151.0 °C and 286.0 °C for AC and DC, respectively. Both NSAIDs exhibit high radiation stability for typical sterilization doses of 25–50 kGy and are likely to be sterilized with radiation at a dose of 25 kGy. The influence of irradiation on changes in molecular dynamics and structure has been observed by 1H-NMR and EPR studies. This study aimed to determine the radiation stability of DC and AC by spectrophotometric, thermal and chromatographic methods. A standard dose of irradiation (25 kGy) was used to confirm the possibility of using this dose to obtain a sterile form of both NSAIDs. Higher doses of radiation (50–400 kGy) have been performed to explain the changes in DC and AC after sterilization.

Assessment methods for interlaboratory comparisons of the dicentric assay

ABSTRACT Purpose To test the performance of different algorithms that can be used in interlaboratory comparisons based on dicentric chromosome analysis, and to evaluate the impact of considering a priori values different to calculate individual laboratory performance based on the ionizing radiation dose estimation. Methods Mean and standard deviation estimations in inter-laboratory comparisons are tested on simulated data and data from previously published inter-laboratory comparisons using three robust algorithms, algorithm A, Algorithm B and Q/Hampel, all programmed in R-project language and implemented in a Shiny application. The simulated data were generated assuming three different probabilities to contaminate inter-laboratory comparisons samples with atypical dose values. Comparison between different algorithms was also done using published exercises where blood samples were irradiated at 0 and 0.7 Gy that represent a challenge for the assessment of an inter-laboratory comparison. Results The best performance was obtained with the Q/Hampel algorithm for the estimation of the dose mean and with the algorithm B for the estimation of the dose standard deviation under the conditions tested in the simulations. The Q/Hampel algorithm showed the best performance when non-irradiated samples were evaluated and there was a high proportion of identical values. The presence identical values causes the Algorithm B to fail. Real examples illustrating the need to consider standard deviation priors, and the need to use algorithms resistant to a high proportion of identical values are presented. Conclusions Q/Hampel algorithm is a serious candidate to estimate the dose mean in the inter-laboratory comparisons, and to estimate both parameters when the proportion of identical values equals or higher than the half of the results. When the proportion of identical values is less than the half of the results, the Algorithm B should be considered as a candidate to estimate the standard deviation in the inter-laboratory comparisons with small number of laboratories. We remark that special attention is needed to establish prior definitions of standard deviation in the assessment of inter-laboratory dicentric assay comparisons.

Synergistic effect of e-beam irradiation and graphene oxide incorporation on thermal, mechanical, and barrier properties of poly (ethylene-co-vinyl alcohol) film

Graphene and its derivatives, such as graphene oxide (GO), have attracted enormous interest from academia and industry because of its unique electrical, mechanical, and thermal properties, which can lead to enhanced material performance. In the present study, low contents of GO were incorporated into the poly (vinyl alcohol-co-ethylene) (EVOH). First, the GO was prepared by chemical oxidation of graphite employing a modified Hummer's method. The GO content of 0.1–0.3 wt % was incorporated in the EVOH matrix using a twin-screw extruder and extrusion blown film process to prepare flexible films. EVOH/GO film samples were irradiated at 100 kGy, using a 1.5 MeV electron-beam accelerator, at room temperature, in the presence of air. GO was characterized by XRD, ATR-FTIR, FE-SEM, and TEM analysis. XRD patterns of GO show a sharp reflection peak at 2θ = 10° (d001) corresponding to a d-spacing at 8.84 Å, characteristic of GO. The non-irradiated and irradiated samples were characterized by XRD, FEG-SEM, TG, DSC, oxygen transmission rate (OTR), UV/VIS analysis, and tensile tests. EVOH/GO nanocomposite films had an improved oxygen barrier, while also retaining fairly good transparency. As an effect of e-beam irradiation, the thermal, mechanical, and barrier behaviors of the nanocomposite films were even better than non-irradiated film samples, and obviously better than neat EVOH. Thus, the incorporation of low contents of GO followed by e-beam radiation treatment might be an interesting alternative to produce packaging materials based on EVOH with outstanding performance even under very humid conditions.

Direct utilization of radioactive irradiated graphite as a high-energy supercapacitor a promising electrode material

Considering ever-increasing energy needs,resultingin the depletion of fossil fuels and, as a corollary, global warming, the adoption of green technologies and the development of sophisticated energy storage and conversion technologies are imperative. Although the supercapacitors have garnered a lot of attention as a high-performance energy storage solution, it is still crucial to engineer novel electrode materials via low-cost and facile, scalable methods while maintaining their enhanced power density and cycle stability. In this work, it was aimed to design and engineer graphite (GRs)-based electrode low-cost materials to be utilized as a high-performance supercapacitor. This study is of great importance in terms of it is one of the first works which offered a facile pathway to fabricate GRs-based electrode materials via the irradiation approach, as well as direct utilization of them in supercapacitor cells. In this regard, various graphite-based samples were prepared by irradiation with several point beam radiation sources, including Am-241, Sr-90, Co-60, and Na-22. The electrochemical active surface area and microcrystalline sizes of GRs were fine-tuned via the type of the radiation source. X-Ray Diffraction (XRD), Raman spectroscopy, and Scanning Electron Microscopy, Energy Dispersive X-Ray (SEM-EDX) techniques were employed to assess the physicochemical features of the as-obtained GRs. The electrochemical behaviors of the samples were further tested in 3.0 M H2SO4 aqueous electrolyte via the coin-cell type supercapacitor cells based on GRs. The maximum specific capacitance was achieved for the GR-Sr90 sample, which was of the largest electrochemically active surface area (0.3087 cm2), as 483.20F.g−1 at a current density of 0.2 A.g−1, which was roughly 5 fold of the non-irradiated GR sample. At the end of the 5,000th CV cycle, the capacitance retention of GR-Sr90 was determined to be 97.40 %. The energy density and power density values of assembled supercapacitor cells based on GRs were found to be comparable to the commercial energy storage systems. All these striking results reveal that the suggested scalable fabrication method will shed an innovative light on the development and engineering of energy storage systems based on low-cost graphite-based electrode materials.

Electron-Beam Irradiated Recombinant Human Collagen-Phosphorylcholine Corneal Implants Retain Pro-Regeneration Capacity

Sterilization of biodegradable, collagen-based implants is challenging as irradiation sterilization methods can alter their mechanical properties. Electron beam (EB) irradiation is a terminal sterilization method that has been used for biologically-derived implants. Here, recombinant human collagen type III-phosphorylcholine (RHCIII-MPC) hydrogels were irradiated with EB doses of 17, 19, or 21 kGy and their subsequent biocompatibility and ability to promote regeneration in rabbit corneas was evaluated. Unirradiated hydrogels stored in 1% chloroform in phosphate-buffered saline (C-PBS) were the controls. There were no significant differences between irradiated and non-irradiated samples in optical or physical properties (tensile strength, modulus, elasticity), or the ability to support cell growth. However, irradiated implants were more sensitive to high levels of collagenase than unirradiated controls and the C-PBS implants had increased cell growth compared to EB and controls at 72 h. Corneal implants e-beamed at 17 kGy or e-beamed and subsequently frozen (EB-F) to increase shelf-life showed no adverse biological effects of the irradiation. EB, EB-F, and C-PBS implanted corneas all rapidly re-epithelialized but showed mild neovascularization that resolved over 6 months. The regenerated neo-corneas were transparent at 6 months post-operation. In vivo confocal microscopy confirmed normal morphology for the epithelium, stroma, sub-basal nerves and unoperated endothelium. Histology showed that all the regenerated corneas were morphologically similar to the normal. Immunohistochemistry indicated the presence of a differentiated corneal epithelium and functional tear film. In conclusion, the e-beamed corneal implants performed as well as non-irradiated control implants, resulting in fully regenerated neo-corneas with new nerves and without blood vessels or inflammation that may impede vision or corneal function. Therefore, a complete validation study to establish EB irradiation as an effective means for corneal implant sterilization prior to clinical application is necessary as a next step.

Change of Optical Properties of Carbon-Doped Silicon Nanostructures under the Influence of a Pulsed Electron Beam

In the work, porous silicon with observed photoluminescence was made from a p-type silicon substrate doped with boron and crystallographic orientation (100) using the method of electrochemical etching in a solution containing H2(SiF6) (silicon hydrofluoric acid) and ethyl alcohol. Thin carbon films were sprayed by high-frequency magnetron sputtering at room temperature onto the surface of porous silicon. The resulting carbon-doped thin films of porous silicon were irradiated on a pulsed electron booster and comparisons were made with nonirradiated films of porous silicon. To understand the effect of carbon on the properties of porous silicon films samples were analyzed by Raman spectroscopy, spectrophotometry, and scanning probe microscopy (SPM). The results of the SPM showed that the roughness of the samples increases after carbon doping on the surface of porous silicon. Thus, for the first time, experimental results were obtained on the effect of irradiation on carbon-doped porous silicon obtained in a solution containing hydrogen hexafluorosilicate H2(SiF6) and a significant change in its optical properties was shown. The results of the study showed that irradiated samples of carbon-doped porous silicon have better photoluminescence compared to nonirradiated samples.

Effect of γ-irradiation on thermally stimulated depolarization current spectra of polyethylene-grafted-poly(Acrylic acid)

The graft copolymerization process of polyethylene (PE) with acrylic acid is performed using a 60Co-gamma irradiator, and the samples are irradiated at different doses, 30, 50, 70 and 100 kGy with a dose rate of 0.55 Gy/s. Global thermally stimulated discharge current (TSDC) spectrum of irradiated and non-irradiated PE-g-AAc has been investigated from RT to ∼ 440K. The TSDC spectrum of non-irradiated PE-g-AAc exhibited two relaxation processes. The first process is located at ∼ 329 K, and the second one is at ∼390 K. These processes are called dipolar and space charge relaxation, i.e. α- and ρ-relaxation, respectively. On the other hand, the position of these processes is shifted towards a higher temperature for irradiated samples. The activation energy for α-relaxation process of non-irradiated samples is ∼ 0.21 eV, while for irradiated samples, it is 0.34 eV. The thermal sampling technique (TS) has been applied to decompose the global TSDC spectrum of all samples into its elementary peaks. The molecular parameters, such as activation energy (Ea ), pre-exponential factor (τ 0), enthalpy (ΔH), entropy (ΔS) and Gibbs free energy (ΔG), are estimated for all samples. The compensation phenomenon has been verified for all samples in different ways, such as plotting ln τ 0 against Ea or entropy versus enthalpy.

Inspection of Radiation Shielding Proficiency and Effect of Gamma-Ray on ESR and Thermal Characteristics of Copper Oxide Modified Borate Bioglasses

Samples of copper-modified bioactive borate glasses were synthesized and their radiation shielding properties including gamma-ray and neutron radiation shielding were investigated. Further, the glasses’ mass attenuation coefficients were measured with a NaI(Tl) detector while their gamma-ray shielding parameters were estimated using Phy-X/PSD program. Free-radical densities were measured via electron spin resonance to estimate the absorbed doses during accidental irradiation. The extensive reduction of the dose detection threshold (2 Gy) required the estimation of the signal of the non-irradiated sample. In addition, the effects of applied microwave power and absorbed dose on synthesized samples were studied. Finally, the thermal annealing of the emerging peaks, which were due to the irradiation signal-to-noise ratio and energy dependence, was studied to estimate the stabilities of such peaks. This modified material is recommended to detect and monitor the gamma-radiation dose because of its good dosimetric properties. Finally, regarding the presence of the two borate groups, triangular and the tetrahedrally coordinated, in their definite and typical wavenumbers, the FTIR spectra displayed simplified vibrations that were close to those of many bioglasses. This paper provides complementary results for the author's previous research examining this glass for low photon dose measurements using luminescence characteristics.

High energy supercapacitors based on functionalized carbon nanotubes: Effect of atomic oxygen doping via various radiation sources

Herein, carbon nanotubes (CNTs) were oxygen functionalized by irradiation with diverse radiation sources including Am-241, Sr-90, Co-60, and Na-22 for the first time to be used as the electrode material in a high-energy supercapacitor. The oxygen contents of the irradiated CNTs were fine-tuned via the energy of the radiation source. The physicochemical characterization of as-obtained CNTs was conducted by X-Ray Diffraction (XRD), Raman, and Scanning Electron Microscopy, Energy Dispersive X-Ray (SEM- EDX) analysis whereas cyclic voltammetry and galvanostatic charge-discharge techniques were performed to assess the electrochemical performance of the as-assembled symmetrical supercapacitor cells. The CNT irradiated by Am-241 radiation source offered superior specific capacitance values compared to the other irradiated CNTs thanks to its higher content of oxygen functional groups. The highest specific capacitance for CNT Am-241 sample (with 7.32% oxygen) was calculated to be 489.6 F.g−1 at a current density of 0.1 A.g−1, which was almost 2.75 fold that of non-irradiated CNT sample. The capacitance retention of as-synthesized CNT Am-241 was determined as 98.50% for the 5,000th CV cycle. The outstanding energy density of 56.90 W.h.kg−1 was achieved even at a high power density value of 9992.19 W.kg−1, comparable to the commercial batteries, will pave the way for facile fabrication of high-energy electrochemical energy storage systems based on functionalized carbon nanotubes.

High photocatalytic activity of Ag/Ag3PO4:W heterostructure formed by femtosecond laser irradiation

In this work, the W-doped Ag3PO4 was prepared by the chemical coprecipitation method and irradiated with a femtosecond laser (FL). The successful formation of the Ag/Ag3PO4:W heterostructure was confirmed by XRD analysis. A higher structural disorder in the [PO4] clusters was observed for the FL irradiated sample (Ag3PO4:W-FL), indicating the formation of Ag metallic from the Ag3PO4 structure. The photocatalytic activity of the samples was studied by photodegradation of rhodamine B under visible light irradiation. The formation of Ag nanoparticles on the surface of Ag3PO4:W led to a degradation rate constant 3.54 times higher than the nonirradiated sample. This higher photocatalytic activity was related to the surface plasmon resonance effect of the Ag metallic, which acts by capturing photoexcited electrons from the Ag3PO4:W, avoiding the recombination of electron-hole pairs, and thus improving the photocatalytic activity.

Optical characteristics of Eu3+ doped alumino borophosphate glass containing Al3+, Zn2+, Li2+, Sr2+ and Ba2+ ions

Europium (Eu3+) doped alumino borophosphate glass (ABP) containing Al3+, Zn2+, Li2+, Sr2+, and Ba2+ was formed by melt quenching method. FT-IR spectroscopy in the range 400–4000 cm−1 was used to describe the vibrational spectrum of the glass sample in order to define the various structural units. The optical absorption spectra of the glass revealed two weak bands due to 7F0 → 5L6 and 7F0 → 5D2 transition of Eu3+ in the UV–Vis range. The direct and indirect band-gap energies were calculated using Tauc’s plot. The refractive index (n) of the prepared glass medium was measured to be decreases as the wavelength increases, and it is varying from 2.25 to 2.07 over the visible region. A photoluminescence spectrum was obtained on non-irradiated glass sample, and the spectra analysis indicated emission peaks (at 593 nm, 615 nm, 653 nm and 703 nm) attributable to the presence of Eu3+. The photo-luminescence decay profile of 5D0 → 7F2 (614 nm) of Eu3+ was also performed to investigate the effect of excitation wavelengths. The luminescence colours of the prepared glass sample were entirely fall on red region (x = 0.648 and y = 0.336) with the dominant wavelength 610 nm in the CIE 1931 chromaticity map. Using CIE chromaticity coordinates, the excitation purity (Pe), colour purity (Pcolour), colorimetric purity (Pcol) and Colour correlated temperature (CCT) were also evaluated. After irradiating the glass with γ-rays at a dosage of 2 kGy, the structural changes caused by the reduction of Eu3+ into Eu2+ ion in the glass matrix was examined using the EPR spectrum as well as its thermo-luminescence characteristics was also studied in the temperature range 300–650 K. The glow curve could be well defined as a superposition of five peaks in the temperature range, and the peaks were explained by second-order kinetics.

Effect of gamma radiation processing on the quality characteristics of anthocyanin rich ethnic rice cultivars

Rice (Oryza sativa L.) is one of the most important cereal crops that serve as staple food of more than 50% of the world population. In recent years great interest has been shown in pigmented & colored rice due to its culinary interest as well as associated health benefits. However, post harvest qualitative and quantitative losses in rice during storage through pests are significant; therefore strategies that are aimed at minimizing losses in the supply chain can have significant socio-economic impact as it may strengthen ‘Food Security’. Fumigation is quite often employed but it is being gradually phased out owing to health and environmental concerns. In the current investigation, effect of different doses of gamma radiation (0.25-1.0 kGy) on the quality attributes (gel consistency, water uptake, total anthocyanin content, phenolics, protein and antioxidant activity) of different prominent ethnic pigmented rice cultivars (5 types) from the state of Manipur, India was evaluated. The cultivars displayed significant variation in their physical quality attributes including dehusked grain color, grain weight and length/breadth ratio. No significant difference was observed in the gel consistency profile of these rice cultivars upon gamma radiation processing (0.25-1.0 kGy). A wide variation was observed in the total anthocyanin content (0.17-4.90 mgCy-3-glu/g in non-irradiated samples) for these pigmented rice cultivars and radiation processing was also observed to exert differential impact on the anthocyanin content (0.24-3.96 mgCy-3-glu/g in irradiated samples) in different cultivars. Total phenolics content (0.22-2.46 mgGAE/g in non-irradiated samples) marginally increased (0.32-2.47 mgGAE/g in irradiated samples) in all the rice cultivars upon radiation processing. Rice cultivars also displayed prominent antioxidant capacity (DPPH scavenging: 20.5-80.5% in non-irradiated samples) and this functional health protective property was found to be retained (DPPH scavenging: 20.8-80.7% in non-irradiated samples) upon gamma irradiation.

Evaluation of the impact of pre-operative stereotactic radiotherapy on the acute changes in histopathologic and immune marker profiles of brain metastases

The unique acute effects of the large fractional doses that characterize stereotactic radiosurgery (SRS) or radiotherapy (SRT), specifically in terms of antitumor immune cellular processes, vascular damage, tumor necrosis, and apoptosis on brain metastasis have yet to be empirically demonstrated. The objective of this study is to provide the first in-human evaluation of the acute biological effects of SRS/SRT in resected brain metastasis. Tumor samples from patients who underwent dose-escalated preoperative SRT followed by resection with available non-irradiated primary tumor tissues were retrieved from our institutional biorepository. All primary tumors and irradiated metastases were evaluated for the following parameters: tumor necrosis, T-cells, natural killer cells, vessel density, vascular endothelial growth factor, and apoptotic factors. Twenty-two patients with irradiated and resected brain metastases and paired non-irradiated primary tumor samples met inclusion criteria. Patients underwent a median preoperative SRT dose of 18 Gy (Range: 15–20 Gy) in 1 fraction, with 3 patients receiving 27–30 Gy in 3–5 fractions, followed by resection within median interval of 67.8 h (R: 18.25–160.61 h). The rate of necrosis was significantly higher in irradiated brain metastases than non-irradiated primary tumors (p < 0.001). Decreases in all immunomodulatory cell populations were found in irradiated metastases compared to primary tumors: CD3 + (p = 0.003), CD4 + (p = 0.01), and CD8 + (p = 0.01). Pre-operative SRT is associated with acute effects such as increased tumor necrosis and differences in expression of immunomodulatory factors, an effect that does not appear to be time dependent, within the limited intervals explored within the context of this analysis.

Effect of gamma rays and accelerated electron beam on medullary lipids decomposition: influence of dose and irradiation temperature.

Ionizing radiation sterilization of non-defatted bone grafts has been found to deteriorate their quality and biocompatibility due to induction of lipid peroxidation products toxic for osteoblast-like cells. Therefore, the purpose of our study was to evaluate the effect of two types of ionizing radiation-gamma rays (G) or accelerated electron beam (EB) applied with two doses at different temperature conditions on hydrocarbons production, resulting from decomposition of palmitic and oleic acids-most abundant fatty acids in medullary lipids. Bone marrow samples isolated from femoral shafts of 6 male donors (aged 46-67 years) were irradiated with G or EB with doses of 25 or 35kGy at different temperature conditions (ambient or deep freezing temperature). Fresh-frozen, non-irradiated samples served as control. Marrow lipids were extracted with n-hexane (Soxhlet's method), hydrocarbons fraction isolated on Florisil column chromatography, separated by gas chromatography and detected by mass spectrometry. Irradiation of bone marrow with sterilization doses of ionizing radiation (G and EB) was found to induce lipid radiolysis as measured by resulting hydrocarbons production. The effect was dose-dependent, whereas no marked influence of radiation type was observed. In contrast, irradiation temperature had a profound effect on lipids decomposition which was partially prevented while irradiation was performed in deep frozen state. Defatting of bone grafts prior to ionizing radiation sterilization seems essential for their biocompatibility, whereas irradiation in a deep-frozen state might compromise the effectiveness of sterilization and needs further studies.

Investigation of optical properties and antibacterial activity of chitosan copper nanoparticle composites

ABSTRACT Chitosan (Cs) doped with different proportion of copper nanoparticles (CuNPs) has been prepared using the casting method in an oven at T = 333 K. The optical properties of Cs/CuNPs have been investigated using different techniques such as, UV-Vis and FTIR spectroscopy. Many optical parameters such as optical band gap energy, oscillation energy, dispersion energy and lattice dielectric constant of all samples have been estimated. FTIR spectra of Cs and Cs/CuNPs have been investigated and the results revealed that, a broadness of OH groups in Cs/CuNPs has been observed. XRD measurements showed that, average of the particle size is approximately ~ 8.11 nm. Measurements of swelling showed that, the maximum swelling decreases linearly with increasing concentration of copper nanoparticles. The antibacterial activity of chitosan and Cs/CuNPs samples has been investigated against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia colii). The results revealed that, irradiated samples with UV-irradiation exhibited a greater activity in comparison to the non-irradiated samples.