Gamma radiation

The influence of gamma radiation on the structure and glass transition behavior of poly-L-lactide (PLLA) has been studied. Since PLLA exposed to high-energy radiation in the presence of air is prone to chain scission reactions and large degradation, changes in molecular weight were obtained by the gel permeation chromatography (GPC). Alterations in the glass transition behaviour were investigated by differential scanning calorimetry (DSC). The apparent activation energy, ?H*, for the glass transition was determined on the basis of the heating rate dependence of the glass transition temperature, Tg. Our findings support the fact that chain scission is the main reason for the decrease of Tg and ?H* with the absorbed dose. At low doses, despite large changes in molecular weight, only small alterations are observed in the glass transition temperature and apparent activation energy. Further increase in the absorbed dose introduces not only significant changes in the molecular weight but ...

The natural polysaccharide Arabic gum is a multifunctional, sustainable material used widely in wastewater treatment technology. Its active functional groups such as hydroxyl, carboxyl, and amino groups facilitate the efficient removal of heavy metals, dyes, pesticides, pharmaceuticals, and persistent organic pollutants. The high surface area and active functional groups facilitate its modification to form various structures such as hydrogels, nanocomposites, or biochar integrated into hybrid adsorption-photocatalysis systems. This review highlights the most familiar forms of Arabic gum in wastewater treatment technology, such as hydrogels, hydrogels nanocomposite, stabilizing agents, coating agents, and bio-activated carbon derived from Arabic gum using different preparation methods. Furthermore, this review outlines the application of Arabic gum as a photocatalyst for the degradation of different pollutants.

A series of polyacrylamide hydrogels (PAAm HGs) and polymers were synthesized by free radical polymerization in the same reaction conditions but using two different media as solvent: water/ethanol at 100/0, 80/20, 70/30, 60/40, 50/50, 40/60, 30/70, and 20/80 (V/V) and water/DMSO at 100/0, 90/10, 80/20, 70/30, 60/40, 50/50, 40/60, 30/70 and 20/80 (V/V). In most cases hydrogels were obtained in high yields and their swelling degree showed a significant dependence with the solvent used in the synthesis. When HGs were synthesized in water/ethanol mixture, the maximum equilibrium swelling (S eq) was reached when the water/ethanol ratio was 60/40(V/V), while for water/DMSO it was obtained for a water/DMSO ratio 80/20. In both cases, these swelling values were higher than when the HGs were synthesized in pure water. The swelling degree achieved by the HGs in water/ethanol was directly related to the yields and the pore size, but this behavior was not observed for the HGs obtained in water/DMSO. In all cases the HGs obtained in water/DMSO swell more than those obtained in water/ethanol. On the other hand, the molar mass of the PAAm polymers prepared in the same reaction conditions, decrease as the proportion of ethanol or DMSO increase. However, the molar mass reached by the polymers obtained in water/DMSO were higher than those obtained in water/ ethanol.

Effects have been studied of gamma-radiation (Е γ =1.25 МeV) in doses of D γ ≤5⋅10 9 rad upon light output and spectral-kinetic luminescence characteristics of new semiconductor scintillators (SCS) based on isovalently doped (with tellurium and oxygen) zinc selenide crystals. SCS crystals have been shown to be of extremely high radiation stability, and changes in their optical and luminescent properties became noticeable only under doses D γ >(7-9)⋅10 7 rad. Under gamma-irradiation with D γ >(2-5)⋅10 9 rad and P γ =7.7⋅10 2 R⋅s -1 , in the surface layer (estimated in tens of nanometers) radiolysis of the crystalline structure occurs, and the loss of mass is observed for the samples (at Т=320 К). Mechanisms are considered that describes variation of SCS properties under pow-erful radiation fluxes.

The present investigation was carried out with two chickpea genotypes IC265291(V1) and IC265298 (V2) collected from NBPGR, New Delhi
and the local chickpea genotype (JG11) collected from ICRISAT to investigate the EMS mutagenic effect on germination percentage and other
seedling characters.The seeds of chickpea treated with various concentrations of EMS (0.1% to 0.6%) and kept the seeds in petriplates in 5
replications each as well as in eld at CPMB, Osmania University.The germination % recorded on 5th day after treatment and other seedling
characters recorded on 10th day. The ANOVA results revealed that highly signicant due to the treatment for all the characters indicating that there
was ample genetic variability in our genotypes. The results showed that highest germination % recorded by the variety IC265928 (100%) in control
followed by 0.1% EMS (100%), 0.2% EMS (93.33%), 0.3% EMS (86.67%), 0.4% EMS (80%), 0.5% EMS (66.67%), 0.6% EMS(60%) and the
reduction of germination % over control at 0.2% EMS (6.67%), followed by 0.3% EMS (13.33%), 0.4% EMS (20%), 0.5% EMS (33.33%) and
0.6% EMS (40%). Among the two genotypes the reduction of germination %, and other traits were found to be more in mutants of IC265291 than
IC265928 and it was also observed that when the EMS concentrations increasing, all the parameters are found to be decreased. The reduction %
was found to be highest at 0.6% EMS in our study. It was found that the plants grown at 0.1% EMS and 0.2 % EMS concentrations showed highest seed germination and seedling characters.These mutants may be utilized for further crop improvement programme in Chickpea.

The effects of gamma radiation from 60 Co and 137 Cs on DNA in aqueous solution are studied experimentally. Using an improved plasmid purification protocol and improved electrophoretic gel analysis techniques provided results with relatively small uncertainties. The results are compared with both theoretical and experimental results. In particular, the results obtained here are discussed in the light of recent discussion on supposed differences of the effects induced by gamma radiation from 60 Co and 137 Cs. We find that the effects of both types of gamma radiation are similar. Keywords Double-strand breaks . Single-strand breaks . Scavenger-derived radicals . Ionizing radiation . pBSKS + DNA . Gamma effects Irradiation of purified DNA molecules has been extensively used during the last decades for studying the interaction of ionizing radiation with DNA [1-13]. The results obtained in such in vitro experiments are, in many aspects, in qualitative agreement with those from irradiation of cells and tissues. For instance, the increase of cell apoptosis as a function of the delivered dose resembles, qualitatively, the increase of SSB (single strand break) and

RESUMO Este trabalho aborda estudos realizados sobre o comportamento de alvos de concre-to especialmente projetados e submetidos a cargas de impacto balístico. São apresenta-dos os efeitos desses impactos sobre o concreto e os resultados alcançados nos artigos apresentados. Constatou-se que a resistência à compressão e a espessura do concreto, e a dimensão máxima do agregado graúdo contribuem para o aumento da resistência ao impacto de alvos de concreto especial. O reforço do concreto também pode alterar a magnitude dos danos gerados pelo impacto balístico. Palavras-chave: concreto, impacto balístico, blindagem. ABSTRACT This paper presents studies about the behavior of concrete targets especially designed and subjected to impact loads. The effects of these impacts on concrete structures are exposed, as well as the results achieved in these studies. It was found that the com-pressive strength and thickness of concrete, and the diameter of coarse aggregate have influence on increasin...

G349.7+0.2 is a young Galactic supernova remnant (SNR) located at the distance of 11.5 kpc and observed across the entire electromagnetic spectrum from radio to high energy (HE; 0.1 GeV < E < 100 GeV) γ-rays. Radio and infrared observations indicate that the remnant is interacting with a molecular cloud. In this paper, the detection of very high energy (VHE, E > 100 GeV) γ-ray emission coincident with this SNR with the High Energy Stereoscopic System (H.E.S.S.) is reported. This makes it one of the farthest Galactic SNR ever detected in this domain. An integral flux F(E > 400 GeV) = (6.5 ± 1.1 stat ± 1.3 syst ) × 10 -13 ph cm -2 s -1 corresponding to ∼0.7% of that of the Crab Nebula and to a luminosity of ∼10 34 erg s -1 above the same energy threshold, and a steep photon index Γ VHE = 2.8 ± 0.27 stat ± 0.20 syst are measured. The analysis of more than 5 yr of Fermi-LAT data towards this source shows a power-law like spectrum with a best-fit photon index Γ HE = 2.2 ±0.04 stat +0.13 -0.31 sys . The combined γ-ray spectrum of G349.7+0.2 can be described by either a broken power-law (BPL) or a power-law with exponential (or sub-exponential) cutoff (PLC). In the former case, the photon break energy is found at E br,γ = 55 +70 -30 GeV, slightly higher than what is usually observed in the HE/VHE γ-ray emitting middle-aged SNRs known to be interacting with molecular clouds. In the latter case, the exponential (respectively sub-exponential) cutoff energy is measured at E cut,γ = 1.4 +1.6 -0.55 (respectively 0.35 +0.75 -0.21 ) TeV. A pion-decay process resulting from the interaction of the accelerated protons and nuclei with the dense surrounding medium is clearly the preferred scenario to explain the γ-ray emission. The BPL with a spectral steepening of 0.5-1 and the PLC provide equally good fits to the data. The product of the average gas density and the total energy content of accelerated protons and nuclei amounts to n H W p ∼ 5 × 10 51 erg cm -3 .

Spatial radionuclides distribution was studied in recent estuarine sediments in the Krka River Estuary. Sediment samples were analyzed for 40 K and 232 Th by gamma-spectrometry. Activities of 40 K were found in the range of 18-457 Bq kg -1 and activities of 232 Th in range of 1.9-29.4 Bq kg -1 . Distribution of 232 Th activities follows that of 40 K, with correlation coefficients higher than 0.97 in all analyzed samples from the Krka River estuary. Spatial distribution of natural radionuclides ( 40 K and 232 Th) in recent estuarine and marine sedimentation area can be a useful tool for recognizing the possible input of terrigenous material, as well as for fast locating of the area where such material is predominantly settled. Krka River Estuary sediments radionuclide distribution gamma-spectrometry 40 K 232 Th * Dedicated to the memory of the late Professor Marko Branica.

Flow cytometry is often used for viability and vitality assessment in bacteria and yeasts. However, its application to the study of fungal spore development is uncommon, probably due to the difficulties in successfully staining these cells. In the current study, we used flow cytometry for the first time to assess the effects of a disinfection treatment on the survival, growth and metabolic activity of fungal spores (Penicillium chrysogenum, Aspergillus nidulans and Aspergillus niger) submitted to gamma radiation (0e15 kGy). The Forward and Side-Scatter parameters of the cytometer were used to assess the differences in size and complexity of particles. Furthermore, two fluorescent dyes were used: Propidium Iodide to assess the membrane integrity and spore viability, in a culture-independent procedure; and Dihydroethidium to measure the changes in metabolic activity of irradiated spores in their first 10 h of growth in a liquid culture medium. Our results support that flow cytometry is a valuable tool in assessing different biological parameters and biocide effects, as it allowed accurate determination of the viability, growth and metabolic activity of gamma-irradiated spores. The fluorescence of Propidium Iodide was 5e7Â more intense in unviable spores. The Dihydroethidium fluorescence increase was associated with faster growth. Control and low radiation doses allowed the germination and growth of spores, while higher doses led to growth inhibition and lower fluorescence.

Fowl cholera (FC) caused by Pasteurella multocida is among the serious infectious diseases of poultry. Currently, formalin inactivated FC (FI-FC) vaccine is widely used in Ethiopia. However, reports of the disease complaint remain higher despite the use of the vaccine. The aim of this study was to develop and evaluate gamma-irradiated mucosal FC vaccines that can be used nationally. In a vaccination-challenge experiment, the performance of gamma-irradiated P. multocida (at 1 kGy) formulated with Montanide gel/01 PR adjuvant was evaluated at different dose rates (0.5 and 0.3 ml) and routes (intranasal, intraocular, and oral), in comparison with FI-FC vaccine in chicken. Chickens received three doses of the candidate vaccine at 3-week intervals. Sera, and trachea and crop lavage were collected to assess the antibody levels using indirect and sandwich ELISAs, respectively. Challenge exposure was conducted by inoculation at 3.5×10 9 CFU/ ml of P. multocida biotype A intranasally 2 weeks after the last immunization. Repeated measures ANOVA test and Kaplan Meier curve analysis were used to examine for statistical significance of antibody titers and survival analysis, respectively. Sera IgG and secretory IgA titers were significantly raised after second immunization (p=0.0001). Chicken survival analysis showed that intranasal and intraocular administration of the candidate vaccine at the dose of 0.3 ml resulted in 100% protection as compared to intramuscular injection of FI-FC vaccine, which conferred 85% protection (p=0.002). In conclusion, the results of this study showed that gamma-irradiated FC mucosal vaccine is safe and protective, indicating its potential use for immunization of chicken against FC.

Fowl cholera (FC) caused by Pasteurella multocida is among the serious infectious diseases of poultry. Currently, formalin inactivated FC (FI-FC) vaccine is widely used in Ethiopia. However, reports of the disease complaint remain higher despite the use of the vaccine. The aim of this study was to develop and evaluate gamma-irradiated mucosal FC vaccines that can be used nationally. In a vaccination-challenge experiment, the performance of gamma-irradiated P. multocida (at 1 kGy) formulated with Montanide gel/01 PR adjuvant was evaluated at different dose rates (0.5 and 0.3 ml) and routes (intranasal, intraocular, and oral), in comparison with FI-FC vaccine in chicken. Chickens received three doses of the candidate vaccine at 3-week intervals. Sera, and trachea and crop lavage were collected to assess the antibody levels using indirect and sandwich ELISAs, respectively. Challenge exposure was conducted by inoculation at 3.5×10 9 CFU/ ml of P. multocida biotype A intranasally 2 weeks after the last immunization. Repeated measures ANOVA test and Kaplan Meier curve analysis were used to examine for statistical significance of antibody titers and survival analysis, respectively. Sera IgG and secretory IgA titers were significantly raised after second immunization (p=0.0001). Chicken survival analysis showed that intranasal and intraocular administration of the candidate vaccine at the dose of 0.3 ml resulted in 100% protection as compared to intramuscular injection of FI-FC vaccine, which conferred 85% protection (p=0.002). In conclusion, the results of this study showed that gamma-irradiated FC mucosal vaccine is safe and protective, indicating its potential use for immunization of chicken against FC.

In this paper, the impact of defects (donor and acceptor traps) which are generated at the Si/SiO 2 interface and in semiconductor bulk, when the gate oxide is exposed to a high electric field stress (HEFS), on n-channel MOS and VDMOS transistors electrical characteristics is analysed and simulated. Taking the advantage of simulation, it was shown how and why the generated traps affect on n-channel MOS and n-channel VDMOS electrical characteristics. 1

The observed spectra of blazars, their intrinsic emission, and the underlying populations of radiating particles are intimately related. The use of these sources as probes of the extragalactic infrared background, a prospect propelled by recent advances in TeV-band telescopes, soon to be augmented by observations by NASA's upcoming Gamma-Ray Large Area Space Telescope (GLAST), has been a topic of great recent interest. Here, it is demonstrated that if particles in blazar jets are accelerated at relativistic shocks, then γ-ray spectra with indices less than 1.5 can be produced. This, in turn, loosens the upper limits on the near infrared extragalactic background radiation previously proposed. We also show evidence hinting that TeV blazars with flatter spectra have higher intrinsic TeV γ-ray luminosities and we indicate that there may be a correlation of flatness and luminosity with redshift.

Tile statistical decay of the Giant Dipole Resonance built on highly excited states of light mass nuclei was studied in inclusive experiments. We report on results of the search for a shape change of hot, fast rotating 4SSc and the test of the isospin purity at high excitation in :sSi and :6A1.

Epoxidized linseed oil (ELO) was synthesized and functionalized with propargylamine (PA) or 3-ethynylaniline (EA) and the products were crosslinked to obtain the diacetylene-functionalized epoxidized linseed oil polymers which were used as matrices in the preparation of the composites with multiwalled carbon nanotubes (MWCNTs). Electrical resistance at percentages between 4 and 20 wt/wt% of filler was measured and the percolation threshold was calculated, obtaining 1.2 and 1.7% for the composites with EA and PA respectively. Low critical concentration evidenced a good dispersion of the MWCNTs without necessity of any modification. The final products were used in the sensing of acetone, chloroform and ethanol. The electrical resistance changes were measured at different concentrations and the sensibility was calculated. In order to improve stability toward the vapors, composites were irradiated with gamma rays and new sensing was done and compared. The results showed differences in sensibility, selectivity and reproducibility.

Biology and biometrics of melon fly, Bactrocera cucurbitae (Coq.) was studied on bitter gourd and pumpkin fruit under laboratory conditions (temperature 26 o C- 30 o C and relative humidity 70-75%) at the, Uttar Banga Krishi Viswavidyalaya, West Bengal, India during 200708. Findings of the study revealed that average length and breadth of egg was more or less similar when reared on bitter gourd and pumpkin (1.28 ± 0.059 mm, 0.26±0.057mm and 1.26 ±0.060 mm, 0.25±0.053mm, respectively). The length of mature maggots also does not show much variation on both the hosts whereas weight of mature maggots was found to be slightly higher in bitter gourd as compared to that of pumpkin. Similarly length and breadth of pre-pupal stage was also noted slightly higher on bitter gourd (6.89±0.46mm. and 2.04±0.23mm. respectively) that pumpkin (6.70±0.60mm. and 1.99±0.22mm. respectively). In both bitter gourd and pumpkin, size of the females was larger than the males. Fecundity and hatchability were n...

After many years of speculation, recent observations have confirmed the association of gamma-ray bursts with core-collapse supernova explosions from massive stars. This association carries with it important consequences. The burst relativistic jet has to propagate through the cold dense stellar material before it reaches the transparency radius and the burst photons are produced. This propagation is likely to affect the initial properties of the jet, shaping it and changing its energy composition. The variability injected at the base of the jet is also likely to be erased by the jet-star interaction. Despite this, GRBs seem to have remarkably predictable properties once the radiative phase sets in, as emphasized by the recent discovery of several tight correlation between spectral, geometric and energetic properties of the jet. In this contribution we discuss the jet interaction with the star, emphasizing its time-dependent properties and the resulting energy distribution. We finally emphasize the surprising predictability of jet and radiation properties outside the star and underline its implication for standardizing the GRB candle.

Campylobacter spp. were isolated from rivers Mula, Mutha and Pavana by preT-Kapadnis Baseri and Preston enrichment-modified charcoal cefoperazone deoxycholate agar methods. Survival studies were conducted in fresh skim cow milk, chicken meat extract and mushroom extract at various temperatures. The sensitivity of Campylobacter strains inoculated in the food samples, to chemical preservatives, gamma radiation, microwave heating and water bath heating was studied. Campylobacter strains survived well in milk and chicken extract; however, temperature significantly affected their survival in those food samples. Although most of the chemical preservatives were effective against Campylobacter isolates, the sub-inhibitory values of acetic acid and lactic acid were relatively lower against these isolates. All the strains investigated for the effect of gamma radiation, were sensitive to doses less than 3 kGy. In case of heat preservation, around 9 min was required to eliminate Campylobacter spp. by heating in water bath at 508C while approximately 13 s from food samples exposed to heating in a microwave oven. The effect of food preservation techniques on Campylobacter varied with the temperature and type of the food. Microwave treatment appeared to be much more effective than water bath heating and that chicken meat extract conferred an additional protection to Campylobacter as compared to milk or PBS.

Radiation protection standards aim to balance public health with enabling beneficial uses of radiation technologies. However, characterizing risks from ionizing radiation exposure presents ongoing scientific challenges, particularly at low doses where epidemiological data is limited. Continued research supporting robust risk quantification remains essential for establishing evidence-based protection policies as technologies and understanding progress. Numerous epidemiological cohorts have provided vital long-term follow-up data on cancer risks from high-dose exposures such as from atomic bombs in Japan. Analysing this dataset remains important for disentangling effects of dose and dose-rate. More recent international collaborative efforts are focusing on populations with lower-dose occupational or medical exposures through pooled analyses merging country-specific databases. Key research priorities include further exploring transmission of risks across generations as well as variations in individual susceptibility that could impact risk prediction. Cornerstone of optimization and providing the safest working conditions for those working in the nuclear industry. Large collaborative databases present opportunities to address limitations through standardized characterization of endpoints and robust dosimetry across settings like occupation and medical radiation exposure history. This paper argues sustained global commitment across disciplinary research remains essential for most accurately characterizing radiation dangers to better guide radiation protection policies worldwide. This paper reviews advances and limitations in current understanding through multidisciplinary research efforts.

Aims. To investigate the efficiency of centrifugal acceleration of particles as a possible mechanism for the generation of ultra-high γ-ray nonthermal emission from TeV blazars, we study the centrifugal acceleration of electrons by rotating magnetic field lines, for an extended range of inclination angles and determine the maximum Lorentz factors γ max attainable by the electrons via this process. Methods. Two principal limiting mechanisms for the particle acceleration, inverse Compton scattering and breakdown of the beadon-the-wire approximation, are examined. Results. Particles may be centrifugally accelerated up to γ max 10 8 and the main limiting mechanism for the γ max is the inverse Compton scattering. Conclusions. The energy of centrifugally accelerated particles can be amply sufficient for the generation (via inverse Compton scattering) of the ultra-high energy (up to 20 TeV) gamma emission in TeV blazars.

Background: Ionizing radiation, commonly used in radiotherapy and industrial applications, is known to cause significant oxidative damage by generating reactive oxygen species (ROS). This damage affects cellular macromolecules, leading to DNA breaks, lipid peroxidation, and depletion of antioxidant defenses. Nanotechnology, particularly the use of bioactive silver nanoparticles (AgNPs), has emerged as a promising strategy for mitigating radiation-induced toxicity. This study investigates the radioprotective effects of caffeine-coated silver nanoparticles in Swiss albino mice exposed to gamma radiation. Methodology: Male Swiss albino mice were pre-treated with caffeine-coated AgNPs at doses of 25, 50, 100, 150, and 200 mg/kg for 15 days, followed by 5 Gy whole-body gamma irradiation. Body weight, liver weight, lipid peroxidation (LPO), and reduced glutathione (GSH) levels were assessed up to 30 days post-irradiation. Results: Moderate doses (50 and 100 mg/kg) improved body and liver weights, reduced LPO, and preserved GSH levels. Low (25 mg/kg) and high doses (150-200 mg/kg) were less effective or showed signs of toxicity. Conclusion: Caffeine-coated AgNPs offer dose-dependent radioprotection against gamma radiation-induced oxidative damage, with 50-100 mg/kg showing optimal effects.

The current research describes the synthesis and testing of FRP under tensile loading and high temperature conditions. The FRP is produced using Vacuum Infusion technique and cut in to different fibre sizes. The SEM (Scanning Electron Microscope) analysis is performed to determine the effect of matrix maturity, temperature, fibre inclination, and loading rate on fibre matrix. The findings have shown relationship of fibre volume on thermal and mechanical characteristics of FRP.

In this study, the effect of pullulan edible coating of Nasturtium officinale extract were investigated in both free and microencapsulated form to enhance the quality and shelf life of Fish nuggets during a 12-day refrigerated storage period. For this purpose, Nasturtium officinale extract was extracted using ultrasound and quantities of phenolic, antioxidant properties. According to the results of phenolic compounds, 792.58 mg gallic acid /g extract, this has antioxidant property. Guar gum-whey protein concentrate was used for micro-encapsulation of the extract.Then in order to investigate the effect of Nasturtium officinale extract on the quality and shelf life of fish nuggets, pullulan based edible coating of this extract in 5 treatments including control, pullulan, pullulan + 1000 ppm extract, pullulan + Nano Extract 1000 ppm and pullulan + TBHQ was prepared. At first, the physicochemical properties of the nugget were measured. The results showed that addition of pullulan and Nasturtium officinale extract reduced oil uptake and increased moisture content, the frying efficiency and softness of Fish nuggets were and overall the best results were obtained in pullulan treatments. The Nano extract and extract were observed (P< 0.05). Then, the production treatments were periodically in the refrigerator chemically and sensory evaluation. The results of this study showed that Nasturtium officinale extract has antioxidant activity and nanocapsulation of the extract increased its antioxidant properties as nugget containing 1000 ppm Nasturtium officinale nanocapsule extract with pullulan process. Organoleptic and oxidative changes were significantly delayed by Fish nuggets (P <0.05). Therefore, it seems that Nasturtium officinale nanocapsule extract with pullulan coating can be used as a natural preservative in Seafood products.

The reliability of electronics in the proximity of the ionizing radiation is a key requirement in particular in high energy physics, nuclear power or space applications. One way to improve robustness of MOS transistors operating in such environments is to use enclosed layout techniques. This special layout approach helps to maintain leakage current of MOS transistors at low level even after irradiation, in contrast to a linear layout MOS transistor, where leakage current could increase by orders of magnitude. The issue, arising with enclosed layout transistors, is related to channel modelling, since the MOS transistor gate geometry is no more a simple rectangle. In this work, modelling of equivalent width and length dimensions of the MOS transistor channel under the gate is addressed. For this purpose transistors of four types and two layout versions, fabricated in a standard 180 nm CMOS process, are characterized. The accuracy of available models for equivalent channel dimensions is analysed, along with a new simplified geometrical model developed by the authors. They are further compared to the empirically extracted aspect ratio. The improvement possibilities for the considered models are then identified.

Detailedexperimental informationon high-spin states (up to -20 ft) in the N >_. 52 nuclei 96,97,98Ruhas been obtained from gamma-rayspectroscopicstudies tbllowing65Cu(36S,pxn) reactions. The level schemesextu'bit sequencesof presumablynegative-parity states linkedby F_.2 transitionswith monotonouslyincreasingenergies. These sequences coexist with the positiveparityyrast states where the transitionenergiesare rather irregular.Thenegative-paritystructures are suggestive of the emergence of rotational collectivity. The data are comparedwith "IRS calculationsfor deformedh11/2neutronconfigurations.

General global cooling over the Neogene has been modulated by changes in Earth's orbital parameters. Investigations of deep-sea sediment sequences show that various orbital cycles can dominate climate records for different latitudes or for different time intervals. However, a comprehensive understanding of astronomical imprints over the entire Neogene has been elusive because of the general absence of long, continuous records extending beyond the Pliocene. We present benthic foraminiferal d 18 O and d 13 C records over the past 23 Ma at Ocean Drilling Program Site 1148 in the northern South China Sea and construct an astronomically tuned timescale (TJ08) for these records based on natural gamma radiation and color reflectance data at this site. Our results show that a 41 ka cycle has dominated sediment records at this location over the Neogene, displaying a linear response to orbital forcing. A 100 ka cycle has also been significant. However, it is correlated nonlinearly with Earth's orbital variations at the 100 ka band. The sediment records also display a prominent 405 ka cycle. Although this cycle was coherent with orbital forcing during the Oligocene and the early Miocene, it was not coherent with Earth's orbital variations at the 405 ka band over the whole Neogene. Amplification of Northern Hemisphere and Southern Hemisphere glaciation since the middle Miocene may be responsible for this change in sedimentary response. Our benthic foraminifera d 18 O and d 13 C records further exhibit amplitude variations with longer periods of 600, 1000, 1200, and 2400 ka. Apparently, these cycles are nonlinear responses to insolation forcing.

The authors, an astronomer/priest and an anthropologist/biologist, describe their use of the dramatic arts at the INSAP VIII meeting in their performance of two short skits on the sighting of a supernova in AD 1054 (creating the beautiful Crab Nebula) and a future "Rho Cas" stellar explosion in the constellation Cassiopeia, in AD 3054. They speculate on the emergence of science, religion, and art as bona fide adaptations, responding to natural selection, which served early hominins well in their struggle for existence. They draw parallels to the continued functions of science, religion, and art in modern society.

Degradation of polyvinyl polymers (polyvinyl formal, polyvinyl alcohol, and polyvinyl acetate) by highenergy heavy ions was analysed with in situ mass spectrometry and infrared spectroscopy. Both at room temperature and at cryogenic temperature, the polymers are severely damaged by scission of side chains and the polymer backbone, releasing a large number of molecular fragments. Correlation of structural analysis of the damaged polymer and mass analysis of its volatile fragments gives plausible reaction mechanisms for the ion induced degradation. These are compared to thermal degradation. The differences found between the two degradation processes are due to the non-equilibrium character of the ion based process with its high electronic excitation and ionisation. The results are of practical relevance for applications of the polymers in devices of particle accelerators and space vehicles.

Background: Ginger (Zingiber officinale), a member of the Zingiberaceae family that contains phenolic compounds such as gingerol, paradol, zingerone, zingiberol and shogaols, has antioxidant, anti-inflammatory, antimicrobial, antifungal and antitumour activity. Materials: The present investigation was intended to evaluate the radioprotective effects of ginger extract in Wistar albino rats against whole-body gamma-ray irradiation. Rats were orally administered 250 mg/kg b.w. of ginger extract by gavage for 14 consecutive days. On the 14 day, 2 hr after the last ginger administration, the animals were exposed to whole-body gamma-rays of 6 Gy. The radioprotective potential of ginger was assessed through measurement of the DNA oxidative stress marker 8-hydroxy-2’-deoxyguanosine in serum, analysis of chromosomal abnormalities and micronucleus formation in bone marrow cells and estimation of DNA impairment in both bone marrow cells and epidydimal sperm using comet assay. Sperm DNA integri...

leakage along the patient plane were 0.005% & 0.0049% and leakage other than the patient plane was 0.0049% & 0.0048% respectively. Survey readings across the facility were below the radiation exposure rate limit set by the regulatory board i.e., less than 10µSv/hr. Institutions which are having LINAC with a photon energy of more than 10MV must carry out the neutron head leakage test and room survey periodically as per the regulatory board and ensure that no excess amount of leakage is evidenced in and around the facility. This study confirmed that there is no harmful neutron leakage at the site and also allows the institute to continue using a 15MV beam and get good clinical outcomes with deep-seated cancer tumors.

Chemical reaction schemes are key conceptual tools for interpreting the results of experiments and simulations, but often carry implicit assumptions that remain largely unveried for complicated systems. Established schemes for chemical damage through crosslinking in irradiated silicone polymers comprised of polydimethylsiloxane (PDMS) date to the 1950's and correlate small-molecule ogassing with specic crosslink features. In this regard, we use a somewhat reductionist model to develop a general conditional probability and correlation analysis approach that tests these types of causal connections between proposed experimental observables to reexamine this chemistry through quantum-based molecular dynamics (QMD) simulations. Analysis of the QMD simulations suggests that the established reaction schemes are qualitatively reasonable, but lack strong causal connections under a broad set of conditions that would enable making direct quantitative connections between o-gassing and crosslinking. Further assessment of the QMD data uncovers a strong (but nonideal) quantitative connection between exceptionally hard-to-measure chain scission events and the formation of silanol (Si-OH) groups. Our analysis indicates that conventional notions of radiation damage to PDMS should be further qualied and not necessarily used ad hoc. In addition, our eorts enable independent quantum-based tests that can inform condence in assumed connections between experimental observables without the burden of fully elucidating entire reaction networks. The reaction schemes of Charlesby have formed the basis for interpreting a wide range of experiments and modeling results J o u r n a l N a me , [ y e a r ] , [ v o l .

The treatment of wastewater and industrial effluents by electron beam irradiation is a promising technique, however, not very widespread in Brazilian territory. The design and construction of a mobile unit by the Nuclear and Energy Research Institute, containing an electron beam accelerator of 700 keV and 20 kW is innovative to demonstrate the effects and positive results of this technology. The aim is to transfer the mobile unit to several companies with interest in liquid waste treatment, connect to the industry electrical system and start the ionization treatment process through electron beam. The mobile unit connection to the local electrical system may be a challenge due to the great diversity of voltages and distances involved, as well as the large injections of harmonic content generated by the electron beam accelerator that can affect sensitive loads in the industrial system. In this work, an analysis of the electrical power system of the mobile unit was made,    regarding t...

Radiation processing of food materials by gamma-radiation is a well-established method for microbial decontamination and insect disinfestation. Irradiation of spices at doses ranging from 10 to 30 kGy has been reported to result in complete elimination of microorganisms with negligible changes in the flavour quality. The effect of gamma-radiation on microflora and vanillin content of cured vanilla beans in the dose range of 5 -50 kGy has been investigated, but its effect on other major aroma compounds and vanillin glucoside (vanillin aroma precursor) remaining after curing have not been studied so far. Vanillin (4-hydroxy-3-methoxybenzaldehyde) is one such compound used as a flavouring agent and as a dietary component. It is the major component of natural vanilla, which is one of the most widely used and important flavouring materials throughout the world. Vanillin is an antioxidant capable of protecting membrane against lipid peroxidation and DNA against strand breaks induced by reactive oxygen species. The present work was aimed to study the effect of gamma-radiation processing on the major aroma compounds of cured vanilla beans and also to investigate possible enhancement in vanillin content by the radiolytic breakdown of vanillin glucoside present already. Cured vanilla beans were irradiated (5, 10, 15, 20 and 30 kGy) and the vanillin content of control and irradiated samples were analysed, respectively for possible enhancement of vanillin content by radiolysis of vanillin glucoside. Radiolytic breakdown of glycosidic precursors of aroma constituents and consequent release of free aroma was shown to result in the enhancement of aroma quality of these products. Since a considerable amount of vanillin exists as its glycosidic precursor in cured vanilla pods, a possible enhancement in yield of vanillin by radiation processing is thus expected. Hence the highly stable oxygen-carbon linkage between vanillin and glucose limits the possible enhancement of aroma quality of irradiated beans.

This article presents a case study on a ceramic vessel belonging to the Amazonian indigenous people, Asurini do Xingu, to investigate the use of gamma radiation for consolidating cultural heritage. Traditionally, gamma radiation is used to impregnate cultural artifacts with a radiocurable resin. In this study, the consolidating resin was applied only to the external surface of the vessel by brushing. The object was weighed before and after consolidation, and a colorimeter was used to evaluate possible color changes. The results indicated that the method was effective, with no negative effects on the appearance of the cultural item.

For decades, ethnographic museums treated the organic objects in their collections with pesticides, including DDT, pentachlorophenol, hexachlorobenzene, and paradichlorobenzene. However, by the late 20th century, the use of pesticides in museums was limited, as certain toxic substances were banned for environmental reasons and due to the risks posed to human health. Currently, the Museum of Archeology and Ethnology (MAE-USP) in São Paulo (Brazil) is treating objects affected by insect infestations using ionizing radiation. In this work, we discuss the decisions that motivated the choice of this method as well as the important partnership with the Institute of Energy and Nuclear Research as a major contributor to sustaining the MAE-USP's collections.

Diffuse VHE γ radiation from the Galactic Centre ridge observed by the H.E.S.S. telescope has been convincingly linked with the propagation of recently accelerated cosmic rays that interact with molecular hydrogen clouds during their diffusion. Through a series of time-dependent simulations of that diffusion for different propagation parameters we have obtained the most probable values of the diffusion coefficient for the Galactic Centre region. Assuming that the diffusion coefficient is of the form κ(E) = κ 0 (E/E 0 ) δ , then for different optimal combinations of κ 0 and δ its value is obtained for cosmic rays originating from a central point (possibly Sgr A East) 10 kyr ago.

A study of radiation effects on various types of glasses, dielectric optical coatings, cemented optics and fiber was undertaken with a view to select them for extreme radiation environments. Samples were exposed to different radiation doses in the Pakistan Research Reactor-I (PARR-I) for neutron and Cobalt 60 source for gamma irradiation. Transmissions were measured before and after irradiation. The dielectric coatings were subjected to additional tests (adhesion, abrasion and humidity, etc.) as per MIL-M-13508C and MIL-C-675C. All 15 glasses studied showed varying amounts of transmission loss as expected, with negligible degradation for three types. Recovery of transmissions with time/ageing was also studied, with more or less complete recovery with temperature annealing. A faster bleaching of darkened/brown glasses was achieved by using UV lamps or UV laser. The dielectric coatings (HR, AR) and one of the two commercial optical cements showed excellent resistance to neutrons and gamma radiations, and could be good candidates for the fabrication and utilization of optical components in extreme radiation environments. The data allowed several Chinese glasses to be studied for the first time.

A field measurement program was undertaken as part NASA's Cold Land Processes Experiment (CLPX). Extensive snowpack and soil measurements were taken at field sites in Colorado over four study periods during the two study years (2002 and 2003). Measurements included snow depth, density, temperature, grain type and size, surface wetness, surface roughness, and canopy cover. Soil moisture measurements were made in the near-surface layer in snow pits. Measurements were taken in the Fraser valley, North Park, and Rabbit Ears Pass areas of Colorado. Sites were chosen to gain a wide representation of snowpack types and physiographies typical of seasonally snow-covered regions of the world. The data have been collected with rigorous protocol to ensure consistency and quality, and they have undergone several levels of quality assurance to produce a high-quality spatial dataset for continued cold lands hydrological research.

We studied the giant dipole resonance (GDR) in 4 He by observing its analog via the 4 He( 7 Li, 7 Be) reaction at an incident energy of 455 MeV and at forward scattering angles. The spin-nonflip ( S = 0) spectrum was deduced by measuring the 0.43-MeV 7 Be γ -ray in coincidence with the scattered 7 Be. The total cross section of photodisintegration to the GDR in 4 He was derived from the S = 0 and L = 1 spectrum. The result agrees well with the previous total photodisintegration data in which the GDR has a pronounced peak at E γ ∼ 27 MeV.

A sample of 286 gamma-ray bursts (GRBs) detected by the Swift satellite and 358 GRBs detected by the RHESSI satellite are studied statistically. Previously published articles, based on the BATSE GRB Catalog, claimed the existence of an intermediate subgroup of GRBs with respect to duration. We use the statistical χ 2 test and the F-test to compare the number of GRB subgroups in our databases with the earlier BATSE results. Similarly to the BATSE database, the short and long subgroups are well detected in the Swift and RHESSI data. However, contrary to the BATSE data, we have not found a statistically significant intermediate subgroup in either Swift or RHESSI data.

We present results from a proton accelerator beam test to measure radiation damage and activation in advanced scintillator materials. Samples of LaBr3:Ce and LaCl3:Ce were exposed to protons from 40-250 MeV at the Proton Irradiation Facility of the Paul Scherrer Institute in Switzerland. Twelve energy bands were used to simulate the spectrum of the South Atlantic Anomaly (SAA), with different samples exposed to the equivalent of 4 months, 1 year, and 5 years of SAA passage. No significant decrease in light output was found due to radiation damage, indicating that these new scintillator materials are radiation tolerant. High-resolution spectra of the samples were obtained before and after irradiation with a Germanium spectrometer to study activation. We present a detailed analysis of these spectra and a discussion of the suitability of these scintillator materials for detectors in future space missions.

The hard X-ray polarimeter POLAR aims to measure the linear polarization of the 50 -500 keV photons arriving from the prompt emission of γ-ray bursts (GRBs). The position in the sky of the detected GRBs is needed to determine their level of polarization. We present here a method by which, despite of the polarimeter incapability of taking images, GRBs can be roughly localized using POLAR alone. For this purpose scalers are attached to the output of the 25 multi-anode photomultipliers (MAPMs) that collect the light from the POLAR scintillator target. Each scaler measures how many GRB photons produce at least one energy deposition above 50 keV in the corresponding MAPM. Simulations show that the relative outputs of the 25 scalers depend on the GRB position. A database of very strong GRBs simulated at 10201 positions has been produced. When a GRB is detected, its location is calculated searching the minimum of the χ 2 obtained in the comparison between the measured scaler pattern and the database. This GRB localization technique brings enough accuracy so that the error transmitted to the 100% modulation factor is kept below 10% for GRBs with fluence F tot ≥ 10 -5 erg cm -2 . The POLAR localization capability will be useful for those cases where no other instruments are simultaneously observing the same field of view.

The Gamma-ray burst (GRB) database based on the data by the RHESSI satellite provides a unique and homogeneous database for future analyses. Here we present preliminary results on the duration and hardness ratio distributions for a sample of 228 GRBs observed with RHESSI.

The ratio of branching fractions of the radiative B decays B 0 → K * 0 γ and B 0 s → φγ has been measured using an integrated luminosity of 1.0 fb -1 of pp collision data collected by the LHCb experiment at a centre-of-mass energy of √ s = 7 TeV. The