In this study, the effects of 325nm wavelength ultraviolet light irradiation on pitting corrosion behavior of type 340 stainless steel in a neutral chloride solution are studied. Further, the change of passive film with the light irradiation is analyzed using x-ray photoelectron spectroscopy. The mains results obtained therefrom are stated below. Pitting potential can be shifted in noble direction by the ultraviolet light irradiation. The effect of ultraviolet light irradiation is ore prominent in the pitting corrosion process than that in the passive film formation. The result of the analysis in terms of the birth and death stochastic probability process shows that pitting corrosion rate is decreased remarkably by the ultraviolet light irradiation at the formation of passive film, while the ...
Multilayer mirrors for the extreme ultraviolet (EUV) are keyelements for numerous applications of coherent EUV sources such as newtabletop lasers and free-electron lasers. However the field ofapplications is limited by the radiation and thermal stability of themultilayers. Taking into account the growing power of EUV sources thestability of the optics becomes crucial. To overcome this problem it isnecessary to study the degradation of multilayers and try to increasetheir temporal and thermal stability. In this paper we report the resultsof detailed study of structural changes in Sc/Simultilayers when exposedto intense EUV laser pulses. Various types of surface damage such asmelting, boiling, shockwave creation and ablation were observed asirradiation fluencies increase. Cross-sectional TEM study revealed thatthe layer structure was completely destroyed in the upper part ofmultilayer, but still survived below. The layers adjacent tothe substrateremained intact even ...
Spontaneous and ultraviolet-induced changeabilities of wine yeasts from the killer state to sensitive one have been studied. Observed often spontaneous changes of killer and neutral phenotypes under laboratory store conditions as well as high mutation frequency of genetic elements responsible for the killer indication on ultravioletirradiation testify that often encounterability in nature and in the production of sensitive yeasts is attributed to high frequency of mutation changes of the killer and neutral phenotypes to the sensitive state.
With conventional heating process, ultraviolet (UV) illumination, and microwave irradiation, we have successfully synthesized UV curable encapsulating adhesives with excellent gas barrier capabilities, good adhesive strength, moderate hardness, and high refractive indices. The experimental results manifest that the physical properties of lab-made encapsulating adhesives are highly dependent on their chemical structures and synthetic procedure. We also discover that the encapsulating adhesive prepared by microwave irradiation (i.e. encapsulating adhesive VI-MW) exhibits better adhesive strength and higher gas resistance than those prepared by conventional heating process and UV illumination. Furthermore, encapsulating adhesive VI-MW has also been applied for the package of organic light emi...
This paper reviews the effects of neutron irradiation on thermal and mechanical properties and bulk tritium retention of armour materials (beryllium, tungsten and carbon). For each material, the main properties affected by neutron irradiation are described and the specific tests of neutron irradiated armour materials under thermal shock and disruption conditions are summarized. Based on current knowledge, the expected thermal and structural performance of neutron irradiated armour materials in the ITER plasma facing components are analysed.
A lamp system with a very soft high-intensity output is provided over a large area by water cooling a long-arc lamp inside a diffuse reflector of polytetrafluorethylene (PTFE) and titanium dioxide (TiO.sub.2) white pigment. The water is kept clean and pure by a one micron particulate filter and an activated charcoal/ultravioletirradiation system that circulates and de-ionizes and biologically sterilizes the coolant water at all times, even when the long-arc lamp is off.
The effect of UV radiation in the wavelength region 230 nm to 302 nm on the ability of an irradiated mammalian cell to reactivate UV-irradiated mammalian virus was tested. An action spectrum for radiation enhanced reactivation (RER) is presented. The shape of the action spectrum points to a combined nucleic acid-protein target for UV radiation effects on this cellular parameter. An analysis of the results of others involving the biochemical and photobiological events involved in RER does not allow us to distinguish which macromolecule is the major contributor to this effect. Studies involving an analogous phenomenon in bacteris (Weigle reactivation) imply that RER and WR amy involve similar mechanisms. (author).
The color centers, which are generated in yttrium-aluminium perovskite (YAP):Nd(1 at.%) and YAP:Er(50 at.%) crystals under the influence of ultraviolet and #gamma#-irradiation, have been studied by absorption spectroscopy. The generated color centers are both stable and transient at room temperature. It is shown that the transient color centers are mainly responsible for the decrease of laser generation efficiency of Nd:YAP and YAP:Er irradiated crystals, although physical mechanisms leading to efficiency decrease are different in these materials. (orig.)
The colour, odour, flavour and texture of a breaded turkey escalope irradiated at doses of 2 and 4 kGy was assessed using a trained sensory panel. Irradiation did not affect raw appearance but during storage the irradiated breaded products became paler than the control samples. The off odour of the raw irradiated products was stronger than that of the unirradiated samples. Irradiation also affected the odour, flavour and texture of the cooked products. Although the trained panelists were able to detect significant differences between irradiated and unirradiated breaded turkey escalopes, the numerical differences between treatments were often quite small. It is possible that an untrained consumer group would be unable to detect these differences. Further research is needed with consumer groups to establish if ...
Oxide superconducting thin films were irradiated with X-rays and ultra-violet (UV) light, and induced radiation effects on electrical and chemical properties were examined by transport measurement, X-ray diffraction analysis (XRD), diamagnetization measurement and X-ray photoemission spectroscopy (XPS). After irradiation for ErBa_2Cu_3O_x films with X-rays emitted from a Rh tube for 100 hours, superconductivity was remarkably damaged, destroying the zero-resistance state. The UV-light irradiation for Bi_2Sr_2CaCu_2O_x films was performed in He gas of about 500 Pa with a low pressure mercury lamp. The superconductivity was gradually degraded with the UV irradiation time up to 70 minutes. In both cases, adequate oxygen-annealing treatments restored superconductivity. The X-ray photoemission spectra showed that the mean Cu valence of the films was decreased approximately from +2 to +1 ...
Two sources of ultraviolet (UV) radiation with peak wavelengths in the UV-C or UV-B ranges were compared for their ability to sterilize contact lenses infected with Pseudomonas aeruginosa, Streptococcus pneumoniae, Acanthamoeba castellani, Candida albicans, and Aspergillus niger. Also examined was the effect of prolonged UV light exposure on soft and rigid gas permeable (RGP) contact lenses. The UV-C lamp (253.7 nm, 250 mW/cm2 at 1 cm) was germicidal for all organisms within 20 minutes but caused destruction of the soft lens polymers within 6 hours of cumulative exposure. UV-C caused damage to RGP lenses in less than 100 hours. The UV-B lamp (290-310 nm, 500 mW/cm2 at 1 cm) was germicidal for all organisms tested (except Aspergillus) with a 180-minute exposure and caused less severe changes in the soft lens polymers than did the UV-C lamp, although cumulative exposure of 300 hours did substantially weaken the soft lens material. RGP materials were minimally ...
Two sources of ultraviolet (UV) radiation with peak wavelengths in the UV-C or UV-B ranges were compared for their ability to sterilize contact lenses infected with Pseudomonas aeruginosa, Streptococcus pneumoniae, Acanthamoeba castellani, Candida albicans, and Aspergillus niger. Also examined was the effect of prolonged UV light exposure on soft and rigid gas permeable (RGP) contact lenses. The UV-C lamp (253.7 nm, 250 mW/cm2 at 1 cm) was germicidal for all organisms within 20 minutes but caused destruction of the soft lens polymers within 6 hours of cumulative exposure. UV-C caused damage to RGP lenses in less than 100 hours. The UV-B lamp (290-310 nm, 500 mW/cm2 at 1 cm) was germicidal for all organisms tested (except Aspergillus) with a 180-minute exposure and caused less severe changes in the soft lens polymers than did the UV-C lamp, although cumulative exposure of 300 hours did substantially weaken the soft lens material. RGP materials were minimally ...
One such agent is the widely used anesthetic, halothane. To study the toxicity of u.v. decomposed halothane, mice were exposed to anesthetic concentrations (1.3%) of non- and u.v.-irradiated halothane in oxygen for 90 min. Halothane sleeping times increased from 14.3 min to 72.5 min. Microsomal mixed function oxidase activity decreased, as shown by prolonged pentobarbital sleeping times 1 day after exposure to halothane and irradiated halothane (54.6 min and 149.1 min, respectively, as compared to a 34.6-min control). Quantitative and qualitative differences were found in the amount of (/sup 14/C)-pentobarbital metabolites excreted by u.v. irradiated halothane-exposed mice compared to either oxygen or non-irradiated halothane-exposed groups. In addition, serum glutamic-oxalacetic transaminase (SGOT) of irradiated halothane-exposed mice increased to 233% of the control values, and ...
Irradiation processing of food in the prepackaged form may affect chemical and physical properties of the plastic packaging materials. The effect of #gamma#-irradiation doses (2.5-10.0 kGy) on polypropylene (PP)-based retortable food packaging materials, were investigated using Fourier transform infrared (FTIR) spectroscopic analysis, which revealed the changes happening to these materials after irradiation. The mechanical properties decreased with irradiation while oxygen transmission rate (OTR) was not affected significantly. Colour measurement indicated that Nylon 6 containing multilayer films became yellowish after irradiation. Thermal characterization revealed the changes in percentage crystallinity.
We have synthesized ozone by irradiating thin solid films of oxygen and oxygen-water mixtures with 100 keV protons, motivated by recent reports of condensed O_3 on icy satellites in the outer Solar system. We measured the depth of the Hartley absorption band in the ultraviolet by reflectance spectroscopy and used it to quantify the column density of ozone. We analyzed the results using a three-component (O, O_2 and O_3) model that successfully explains the fluence dependence of ozone production.
Effects of gamma irradiation on essential oils of five medicinal plants i.e. dried seeds of piper cubeba(cubeb), piper nigrum(black pepper), piper retrofractum, amomum cardamomum(cardamom) and myristica fragrans(mace), packed in low density polyethylene bag of 0.13 mm thickness have been investigated. After being irradiated at doses of 5 and 10 kGy, a part of the samples was analysed, and the rest were stored for six months at temperature of 30 +- 2 degC, and humidity ranging from 70 to 95%. The essential oil characteristics of control, irradiated and six month stored samples were analysed using infrared and ultraviolet spectrophotometers, HPLC, GLC and refractometer. Other parameters observed were moisture content and essential oil content of the samples. Results showed that irradiation up to a dose of 10 kGy do not give any significant effect on these parameters. Significant ...
The irradiation behavior of Li{sub 2}TiO{sub 3} under a fusion reactor environment was simulated by simultaneous irradiation of Li{sub 2}TiO{sub 3} by the triple ion beams and the respective single ion beams of O{sup 2+}, He{sup +} and H{sup +}. The microstructural changes in Li{sub 2}TiO{sub 3} caused by the irradiation were measured by Raman spectroscopy and FT-IR photoacoustic spectroscopy. The results suggest that the formation of TiO{sub 2} due to displacements by irradiation occurs, and the irradiation defects generated by irradiation trap hydrogen and increase the amount of hydroxyl near the surface. Such phenomena are believed to significantly affect the chemical form of the released tritium and the tritium inventory in the breeding materials of a fusion reactor.
The irradiation behavior of Li_2TiO_3 under a fusion reactor environment was simulated by simultaneous irradiation of Li_2TiO_3 by the triple ion beams and the respective single ion beams of O"2"+, He"+ and H"+. The microstructural changes in Li_2TiO_3 caused by the irradiation were measured by Raman spectroscopy and FT-IR photoacoustic spectroscopy. The results suggest that the formation of TiO_2 due to displacements by irradiation occurs, and the irradiation defects generated by irradiation trap hydrogen and increase the amount of hydroxyl near the surface. Such phenomena are believed to significantly affect the chemical form of the released tritium and the tritium inventory in the breeding materials of a fusion reactor.
uv irradiation (365 nm) of air-saturated methanol solutions of 20 drugs absorbing in the 300 to 400 nm region gave rise to oxygen uptake, as determined with a polarographic oxygen electrode. The drugs were tested for photosensitizing capability by either a Type I (free radical) or a Type II (single molecular oxygen) mechanism. This testing was done by the inclusion of either acrylamide or 2,5-dimethylfuran in the irradiated drug solution, with observation of the subsequent polymerization or oxidation, respectively. Phenothiazine and thiazide derivatives appear capable of photosensitization by both mechanisms; promethazine, trifluoperazine, and furosemide show relatively high reactivity. Diazepam (weak), hexachlorophene, aminacrine, pyrilamine, tetracycline, demeclocyline, quinine, and anthracene (strong) react only by a Type II mechanism, with a photosensitizing efficiency increasing in the order given. A correlation appears to exist with ...
An investigation was made of the accumulation of laser damage to transparent polymers irradiated with nanosecond pulses from neodymium and ruby lasers. The damage was investigated by the method of scattering and luminescence in the visible and near ultraviolet parts of the spectrum. It was established that there were two stages in laser damage by repeated irradiation with pulses of intensity below the single-shot damage threshold. An absorbing defect evolved during the first stage in such a way as to create a thermal instability in the surrounding matrix. During the second stage this thermal instability caused spatial growth of laser damage because of propagation of an ionization-inducing absorption wave with a front traveling at the rate governed by the electron component of the thermal conductivity.
The irradiation behavior of Li{sub 2}TiO{sub 3} under a fusion reactor environment was simulated by simultaneous irradiation of Li{sub 2}TiO{sub 3} by the triple ion beams and the respective single ion beams of O{sup 2+}, He{sup +} and H{sup +}. The microstructural changes in Li{sub 2}TiO{sub 3} caused by the irradiation were measured by FT-IR photoacoustic spectroscopy. The results suggest that the amount of TiO{sub 2} formed is proportional to the dpa and that the method of irradiation does not affect the dependence of formation of TiO{sub 2}. On the other hand, the amount of defects and/or radiolytic products generated by irradiation, which is considered to trap hydrogen near the surface, is found to be affected by the method of irradiation. Such phenomena are believed to affect the tritium ...
The irradiation behavior of Li_2TiO_3 under a fusion reactor environment was simulated by simultaneous irradiation of Li_2TiO_3 by the triple ion beams and the respective single ion beams of O"2"+, He"+ and H"+. The microstructural changes in Li_2TiO_3 caused by the irradiation were measured by FT-IR photoacoustic spectroscopy. The results suggest that the amount of TiO_2 formed is proportional to the dpa and that the method of irradiation does not affect the dependence of formation of TiO_2. On the other hand, the amount of defects and/or radiolytic products generated by irradiation, which is considered to trap hydrogen near the surface, is found to be affected by the method of irradiation. Such phenomena are believed to affect the tritium release behavior from Li_2TiO_3, and durability of Li_2TiO_3 ...
Zooplankton tolerant to ultraviolet radiation (UVR) could be indirectly affected by UVR through interactions with UV-sensitive species in the same ecosystem. In Lake Giles, Pennsylvania, USA, the calanoid copepod Leptodiaptomus minutus is more UVR tolerant than the cohabiting species Daphnia catawba and Cyclops scutifer. We asked whether L. minutus is affected by UV-induced mortality of a food competitor (D. catawba) or a predator of its nauplii (C. scutifer). We conducted two in situ enclosure experiments with six treatments: L. minutus alone, L . minutus + Daphnia and L. minutus + Cyclops in the presence and absence of UVR. There were few differences in survival among treatments in Experiment 1, which had enhanced food and a cumulative UVR (320 nm) dose of 9.3 kJ m-2. In Experiment 2, wh...
The polymerization of vinyl pyrrolidinone on nylon 66, with the assistance of aqueous phenol and formic acid, was investigated by mutual and post irradiation procedures. Both solvents were found to greatly facilitate the polymerization with the post irradiation procedure, whereas neither presented any advantage with the mutual irradiation procedure. Tensile properties of the modified fibers were affected in similar ways by both the irradiation procedures and solvents in that the only notable changes were the somewhat higher extensions at yield and at break. The moisture regain values of the treated yarns and fabrics were increased up to three-fold. Surface morphology of the modified fibers was revealed by SEM.
Influence of gamma irradiation and storage on the microbial load, chemical and sensory quality of chicken kabab was investigated. Chicken kabab was treated with 0, 2, 4 or 6 kGy doses of gamma irradiation. Treated and untreated samples were kept in a refrigerator (1-4 deg. C). Microbiological, chemical and sensory characteristics of chicken kabab were evaluated at 0-5 months of storage. Gamma irradiation decreased the microbial load and increased the shelf-life of chicken kabab. Irradiation did not influence the major constituents of chicken kabab (moisture, protein and fats). No significant differences (p>0.05) were observed for total acidity between non-irradiated (control) and irradiated chicken kabab. Thiobarbitric acid (TBA) values (expressed as mg malonaldehyde (MDA)/kg chicken kabab) and volatile basic nitrogen (VBN) in chicken kabab were not ...
The water soluble, photolabile nitrene precursor, azidonaphthalene-2,7-disulfonic acid (ANDS) was encapsulated in small unilamellar, isoelectric (egg PC) or negatively charged (egg PC + dihexadecylphosphate) liposomes. The individual and combined effects of heme-proteins and UV irradiation on the fluorescence of these vesicles under aerobic conditions were studied. Consistent with the catalytic action of heme-proteins on lipid peroxidation and peroxide decomposition, addition of cytochrome c (positively charged) or catalase (negatively charged) to the vesicles elicited immediate formation of a fluorescence band at 470 nm, characteristic of Schiff bases that form from aldehyde byproducts of decomposing hydroperoxides. Ultravioletirradiation of liposomes caused no significant changes in the fluorescence spectrum, in spite of the radiolysis of ANDS inside the vesicles with consequent formation of nitrene radicals. When ...
Full text of publication follows: Li{sub 2}TiO{sub 3} is regarded as one of the most suitable candidates for the solid tritium breeder material of D-T fusion reactors. It is known that, in an operating fusion reactor, the radiation damage in Li{sub 2}TiO{sub 3} will be caused by fast neutrons, energetic tritons and helium ions generated in {sup 6}Li(n,{alpha}){sup 3}H reaction. The irradiation damage caused by such radiation may result in the microstructural changes, and the changes may affect the characteristics of Li{sub 2}TiO{sub 3} such as tritium release behavior. Thus the study of irradiation defects and microstructural changes caused by irradiation in Li{sub 2}TiO{sub 3} is essential to evaluate its irradiation performance. Simulation of the fusion reactor environment and hence the study of a synergistic effect of atomic displacement damage in Li{sub 2}TiO{sub 3} are ...
The effect of both dopant and neutron radiation on the optical and thermal properties of polyvinyl chloride (PVC) has been studied. The doped samples with Pb and Cd were irradiated with a 14 MeV-neutron fluence in the range 7-28.8 x 10"9 n/cm"2. The optical energy gap E_o_p exhibits a significant dependence on the type of additive and the neutron irradiation fluence. The specific heat at constant pressure C_p showed a nonmonotonical change with radiation fluence. The results of this study show that PVC:Pb behaves as a crystalline structure which is only slightly affected by neutron irradiation, while PVC:Cd is highly affected. (author).
In the bacterial reversion assay with S. typhimurium TA98, TA100, TA1535 and TA1537, gamma irradiated hyaluronic acid (10 and 50 kGy) did not induce a significant increase in the number of revertant colonies in the presence of S9 metabolic activation system. In chromosomal aberration tests with CHO cells, gamma irradiated hyaluronic acid (10 and 50 kGy) did not result in an increase in the frequency of chromosomal aberrations. In vivo mouse micronucleus assay, gamma irradiated hyaluronic acid (10 and 50 kGy) did not show an increase in the frequency of polychromatic erythrocytes with micronuclei. These results indicate that hyaluronic acids irradiated at 10 and 50 kGy did not show any genotoxic effects under these experimental conditions. In order to evaluate their possible subacute toxicity, the male and female of ICR mouse were given to methanol extract of 50 kGy irradiated red ...
Volatile compounds produced in flexible food packaging materials (LDPE, EVAc, PET/PE/EVOH/PE) during electron beam irradiation were isolated by purge and trap technique and identified by combined gas chromatography-mass spectrometry (GC/MS), after thermal desorption and concentration. For comparison purposes non-irradiated films were also studied. Film samples were irradiated at low (5 kGy, corresponding to cold pasteurization), intermediate (20 kGy, corresponding to cold sterilization) and high (100 kGy) doses. It was observed that a number of volatile compounds are produced after irradiation in all cases. Furthermore the amounts of all volatile compounds increase with increasing irradiation dose. Both primary (methyl-derivatives etc.) as well as secondary i.e. oxidation products (ketones, aldehydes, alcohols, carboxylic acids etc.) are produced upon ...
The efficacy of gamma irradiation as a method of decontamination for food and herbal materials is well established. In the present study, Glycyrrhiza glabra roots were irradiated at doses 5, 10, 15, 20 and 25 kGy in a cobalt-60 irradiator. The irradiated and un-irradiated control samples were evaluated for phenolic contents, antimicrobial activities and DPPH scavenging properties. The result of the present study showed that radiation treatment up to 20 kGy does not affect the antifungal and antibacterial activity of the plant. While sample irradiated at 25 kGy does showed changes in the antibacterial activity against some selected pathogens. No significant differences in the phenolic contents were observed for control and samples irradiated at 5, 10 and 15 kGy radiation doses. However, phenolic contents increased in ...
The purpose of this study is to evaluate the synergistic effect of helium and hydrogen on Fe-Cr ferritic model alloys, to provide basic understanding concerning development of fusion reactor components. Single, dual and triple ion-beams consisting of Fe{sup 3+}, He{sup +} and H{sup +} were used for irradiation, at temperatures 470-600 deg. C and dose to 50 dpa at 1 {mu}m. The dual beam irradiation with He enhanced cavity nucleation extensively to swelling of about 0.4%, whereas the dual beam irradiation with H did not significantly affect the microstructure. In the case of triple ion irradiation, the synergistic effect of He and H was confirmed clearly; relative large void formation and enhanced swelling to almost 5%. The synergistic effect suggests that the role of H is important for void growth and dislocation bias.
Experiments were designed to elucidate whether or not the irradiated bone marrow cells receive any stimulation for the self-replication and differentiation from normal 'stromal' cell colonies in the bone marrow cell culture in vitro. When irradiated or unirradiated bone marrow cells were overlaid on the normal adherent cell colonies, the proliferation of haemopoietic stem cells was supported, the degree of the stimulation depending on the starting cellular concentration. There was, however, no significant changes in the concentration of either CFUs or CFUc regardless of the dose of irradiation on the bone marrow cells overlaid. This was a great contrast to the dose-dependent decrease of CFUs or CFUc within the culture in which both the stem cells and stromal cells were simultaneously irradiated. These results suggest that the balance of self-replication and differentiation of the ...
The methods introduced for the field of cleaning waste water can be classified under various processes. Chemical oxidation is done with ozone, hydrogen peroxide and ultravioletirradiation with subsequent biological decomposition. Another method is ultra-filtration with recovery of valuable materials or waste water ponds with algae biomass to decompose ammonium compounds, nitrates and phosphates. (EF) [Deutsch] Die auf dem Gebiet der Abwasserreinigung vorgestellten Methoden kann man in verschiedene Verfahren einordnen. Die chemische Oxidation erfolgt mit Ozon, Wasserstoff-Peroxid, UV Bestrahlung und anschliessenden biologischen Abbau. Eine andere Methode ist die Ultrafiltration mit Rueckgewinnung von Wertstoffen oder Abwasserteiche mit Algenbiomasse zum Abbau von Ammoniumverbindungen, Nitraten und Phosphaten. (EF)
Oxide charge on the sidewalls of SiO{sub 2} embedded silicon wires with 20x20 nm{sup 2} cross section is shown to influence the Schottky barrier height for Pd{sub 2}Si/Si junctions positioned on the end surfaces of the wires. Compared with results on planar silicon surfaces, the electron barrier height is 0.3 eV lower for wires investigated as fabricated. By increasing the oxide charge through irradiation by ultraviolet light, the electron barrier decreases by an additional 0.15 eV and the hole barrier correspondingly increases by about the same amount. The phenomenon is explained by assuming an oxide charge density in the range of 10{sup 12} cm{sup -2}.
There are several methods of generating OH free radicals from ozone and/or hydrogen peroxide and ultraviolet light. They all have in common that the OH free radicals originate in one single source only whereas in the combination of ozone with ionizing radiation two simultaneous working sources for the OH free radicals exist. The resulting higher OH free radical concentration makes this process especially apt for the remediation of low level contaminated groundwater as for example trichloroethylene (TCE) contamination in the sub-ppm range. A cost comparison between O_3/UV and O_3/electron beam for remediation of a groundwater contaminated with 100 ppb TCE indicated that for a throughput of about 5 million gallons/day the O_3/electron beam process is more cost-effective. (authors).
adult males and females, less than 24 hours old, of the spiny bollworm, Earias Insulana boisd. were irradiated with sub sterilizing doses of 50,80,100 and 150 gray (Gy). treated moths were out crossed with normal adults and observed for their ability to reproduce. inherited deleterious effects resulting from irradiation of p_1 moths were recorded for several generations. the reduction in both fecundity and egg viability increased by increasing the dose applied to p_1 adult moths .at all tested doses, the females were more radiosensitive than males, as for reduction in fecundity and egg viability. the progeny from irradiated parental females are not as sterile as the progeny from irradiated parental males. the reduction of egg hatching continued in the progeny of irradiated males through F_1 and to lesser extent through F_2 .on the other hand , irradiation of P_1 ...
Neutron irradiation embrittlement of reactor pressure vessel (RPV) steels is one of the critical issues on aging management for long term operation of nuclear power plants. Mechanistic understanding of embrittlement is a key to accurate prediction of embrittlement, especially after long term operation where the mechanical test data are sparse. Since matrix hardening is the source of the embrittlement, we focus on matrix hardening of A533B bainitic pressure vessel steel. Bainitic matrix is composed of lath structure made by ferrite and carbides, therefore it is important to understand how this structure affects hardening behavior, and to understand irradiation response of each phase. As the typical dimension of lath structure of A533B is about one micron, nanoindentation technique is suitable for the estimation of hardening of each phase. MV ion accelerators were used for controlled irradiation because ...
This study was undertaken to determine if a combined treatment (marinating in natural plant extracts or vacuum) with irradiation could have a synergistic effect, in order to prevent the lipid oxidation resulting in the development of undesirable flavours. The fresh chicken legs were irradiated at 0,3 and 5 kGy. The fatty acids composition of lipids was identified using gas liquid chromatography. The effect of irradiation treatment combined with a pre-treatment on the fatty acids composition was followed. The day after irradiation, ten panallists were asked to evaluate, using the instruction scaling, the overall appearance, the odor, the flavor and the overall acceptability of the samples. The major fatty acids identified in lipids were oleic acid, palmitic acid, palmitoleic acid and stearic acid. Pre-treatments have a significant effect on linoleic acid (C18:2) and higher fatty acids. The unsaturated ...
Recently, organic semiconducting materials have gained a broad interest due to their potential for organic electronic devices such as organic light emitting diode (OLED), organic photovoltaic devices and organic field-effect transistors (OFETs). Optical properties of organic semiconducting materials are important for practical application. For example, the power conversion efficiency of organic photovoltaic devices is mainly affected by absorption properties of organic materials. Proton irradiation is one of the efficient methods to change the optical properties of organic materials. In this paper, we investigate the changes of optical properties of various polymers using the proton irradiation.
Argon ions irradiation of 12% Cr steels and Fe/Cr alloys results in the hardening up to 10000 MPa. This value exceeds the hardening level even for martensitic transformation. Along with the increase of microhardness following irradiation the shape of X-ray graph of the affected materials changes considerable. Hardening value and behavior are determined by temperature radiation doze, preliminary ageing, extent of cold strain and alloying. The odserved phenomenon is supposed to be caused by irradiation-induced structural transformations. Reversibility of radiation hardening of the materials in question was observed.
A detailed treatment is introduced to measure the dynamic stability of the relativistic electrons in a self-amplified spontaneous emission free-electron laser (FEL) system, which includes the numerical approach of the Kolmogorov entropy (entropy-like quantity), the general equations of motion for a charged particle and the method of monitoring the simulation accuracy. Numerical experiments reveal a new phenomenon that there exists the possibility of the transition from chaotic to non-chaotic phase-space trajectories of the strongly relativistic electrons due to the effect of their self-fields. The adiabatic magnetic field of a one-dimensional wiggler may have a slight influence on the electron transportation in the absence of the FEL fields, but substantially affects the dynamic stability of the electrons in the process of the FEL interaction. Moreover, the laser fields diminish the dynamic stability of the electrons as the FEL interaction grows exponentially.
The photobiology of mouse melanocyte lines with different pigment genotypes was studied by measuring colony-forming ability after irradiation. The cell lines were wild-type black (melan-a) and the mutants brown (melan-b) and albino (melan-c). Four lamps emitting various UV wavelengths were used. These were germicidal (UVC, 200-280 nm), 82.3% output at 254 nm, TL01 (UVB, 280-320 nm), 64.2% at 310-311 nm, FS20, broadband with peak output at 312 nm and Alisun-S (UVA, 320-400 nm), broadband with peak output at 350-354 nm. Appropriate filtration reduced the contaminating UVC to nonlethal levels for the longer waverange lamps. It is clear from these studies that, in pigment cells, monochromatic results cannot predict polychromatic responses and that cell death from solar irradiations is a complex phenomenon that depends on more than DNA damage. (author).
Scrotal skin of black Long-Evans rats and human thigh skin were maintained in vitro as organ cultures for as long as 14 days, and examined histologically using the combined skin splitting and Dopa techniques. Selected rat skin cultures received testosterone in the culture medium and/or were irradiated with ultraviolet light (290 to 320 nm uvl). With increased time in culture, scrotal melanocytes round up and there is an increase in epidermal pigmentation. Human skin behaves similarly; after eight days in vitro human melanocytes also become rounded, but remain strongly Dopa-positive. Addition of exogenous testosterone to cultured rat skin maintains dendritic morphology of melanocytes, but cell body size is still reduced. uvl irradiation stimulates melanocytes in rat skin cultures, maintaining their dendritic morphology and increasing epidermal and dermal pigmentation. Cultured skin receiving both uvl and testosterone ...
Since antioxidants have been shown to play a major role in preventing some of the effects of aging and photoaging in skin, it is important to study this phenomenon in a controlled manner. This was accomplished by developing a simple and reliable in vitro technique to assay antioxidant efficacy. Inhibition of peroxidation by antioxidants was used as a measure of relative antioxidant potential. Liposomes, high in polyunsaturated fatty acids (PUFA), were dispersed in buffer and irradiated with ultraviolet (UV) light. Irradiated liposomes exhibited a significantly higher amount of hydroperoxides than liposomes containing antioxidants in a dose- and concentration-dependent manner. Lipid peroxidation was determined spectrophotometrically by an increase in thiobarbituric acid reacting substances. To further substantiate the production of lipid peroxides, gas chromatography was used to measure a decrease in PUFA substrate. In order ...
The presence of washed or unwashed cellophane alone or together with a bleomycin, mitomycin C or hydrochlorothiazide, ('Esidrex') showed no appreciable effect on survival of either unirradiated or irradiated conidia. Irradiation for a period of 20min reduced the survival of conidia to 20%. The growth of irradiated conidia in the presence of bleomycin, mitomycin C or Esidrex is associated with a 2- to 3-fold increase in the frequency of gene convertants, but was not accompanied by an increase in point mutants. When conidia were grown on cellophane but otherwise treated as before the frequency of gene convertants was increased 8-fold, but induction of point mutants was negligible. This effect was the same for irradiated and unirradiated conidia. The environment created by the cellophane in contract with the medium appears to affect the action of each of the three compounds ...
The presence of washed or unwashed cellophane alone or together with a bleomycin, mitomycin C or hydrochlorothiazide, ('Esidrex') showed no appreciable effect on survival of either unirradiated or irradiated conidia. Irradiation for a period of 20min reduced the survival of conidia to 20%. The growth of irradiated conidia in the presence of bleomycin, mitomycin C or Esidrex is associated with a 2- to 3-fold increase in the frequency of gene convertants, but was not accompanied by an increase in point mutants. When conidia were grown on cellophane but otherwise treated as before the frequency of gene convertants was increased 8-fold, but induction of point mutants was negligible. This effect was the same for irradiated and unirradiated conidia. The environment created by the cellophane in contract with the medium appears to affect the action of each of the three ...
Sodium-dependent high-affinity choline uptake was measured in various regions of the brains of rats irradiated for 45 min with either pulsed or continuous-wave low-level microwaves (2,450 MHz; power density, 1 mW/cm2; average whole-body specific absorption rate, 0.6 W/kg). Pulsed microwave irradiation (2-microseconds pulses, 500 pulses/s) decreased choline uptake in the hippocampus and frontal cortex but had no significant effect on the hypothalamus, striatum, and inferior colliculus. Pretreatment with a narcotic antagonist (naloxone or naltrexone; 1 mg/kg i.p.) blocked the effect of pulsed microwaves on hippocampal choline uptake but did not significantly alter the effect on the frontal cortex. Irradiation with continuous-wave microwaves did not significantly affect choline uptake in the hippocampus, striatum, and hypothalamus but decreased the uptake in the frontal cortex. The effect on the frontal ...
In a supercritical water-cooled reactor, property of water changes significantly around the critical point. It is expected that irradiation and change of water property will affect the chemistry and material corrosion. Deep understanding of interactions between supercritical water and materials under irradiation is important. However, comprehensive data on radiolysis, kinetics, corrosion and thermodynamics have not been obtained due to the severe experimental condition. To get such data by experiments and computer simulations, a national program funded by Ministry of Education, Culture, Sports, Science and Technology (MEXT) has been started since December 2002. (author)
The helium releases were investigated in FBR fuel pins irradiated to high burn-up. The released amounts increased with the increase of burn-up, but no burn-up dependence of their release fraction to total amounts generated was seen. The contents of "2"4"1Am in fuel pellets affected the released amounts. The effect of released helium on the internal pressure in fuel pins was smaller in FBR fuel pins than in LWR fuel pins, but released helium in fuel pins containing increased amounts of "2"4"1Am, which are anticipated in future FBRs, is expected to affect the internal pressure.
The influence of radiation on the corrosion of the fuel claddings in a Light Water Reactor (LWR) has been the subject of many investigations, and different aspects of the overall phenomena have been studied by different techniques. Analysis of the evolution of Secondary-Phase Particles (SPPs) for different periods of immersion of the cladding in the reactor enables the rate of corrosion to the structure of the material to be correlated. In the case of Zircaloy-2 in a Boiling Water Reactor (BWR), SPPs are dissolved under irradiation, and their dissolution affects the rate of oxidation and other correlated phenomena. In recent studies, the Zircaloy-2 in claddings loaded in the Leibstadt BWR are analysed after one, three and five cycles. Results are presented, and give an account of the changes which occurred in the materials under irradiation. (authors)
The effect of five doses of gamma radiation: 10, 100, 500, 1000 and 5000 Gy on chlorophylls content, net photosynthesis and respiration of chlorella pyrenoidosa has been studied. A decrease in chlorophylls levels is produced after irradiation at 500, 1000 and 5000 Gy, being, at first 'b' chlorophyll affected to a greater extent than 'a' chlorophyll. Net photosynthesis and respiration decline throughout the time of the observations after irradiation, this depressing effect being much more remarkable for the first one. Net photosynthesis inhibition levels of about 30% have got only five hours post irradiation at a dose of 5000 Gy. (author).
Full - grown pupae of the cotton leaf worm Spodoptera littorals (Boisd.) were gamma - irradiated with low doses of 25,50,75, or 100 Gy for male line and with 50 or 100 Gy for female line . The effects on reproduction, development and sex ratio were the biological aspects studied among P1,F1,F2 and F 3 generations . Also, the effects of dose accumulation applied grown male pupae through two or three filial generations and the retarded influence on their F1,F2,and F 3 progeny were examined. In another trial the histological examinations for ovaries and testes of irradiated parents and for their generation were made . The F1 males were more sterile than irradiated parental males while F1 females were more fertile than their irradiated parental females. Irradiation of P1 males did not clearly affect neither the percentage of mated females nor the average number of ...
The inherited sterility of the spiny bollworm Earias Insulana Boisd. Irradiated as parental male adults, with sub sterilizing doses of 100-200 Gy has been studied throughout three successive generations. In general, the female fecundity decreased at the three doses of irradiations (100, 150 and 200 Gy) throughout P_1. F_1, F_2 and F_3 generations as compared to control. The reduction was insignificant in all treatments with some exceptions at 200 Gy, in the parental generation and 150 and 200 Gy bin F_2 generation. Egg hatch of the parental generation was obviously reduced at 100, 150 and 200 Gy treatments as compared to the control. The progeny of F_1 males were evidently more sterile than their irradiated male parents. The effect continued in the F_2, population, however F_3 males almost regained their fertility. Irradiation of P_1 males did not greatly affect mating ability among ...
High energy radiation was studied as a means for destroying hazardous organic chemical wastes. Tests were conducted at bench scale with a {sup 60}Co source, and at full scale (387 l/min) with a 1.5 MV electron beam source. Bench scale tests for both benzene and phenol included 32 permutations of water quality factors. For some water qualities, as much as 99.99% of benzene or 90% of phenol were removed by 775 krads of {sup 60}Co irradiation. Full scale testing for destruction of benzene in a simulated waste-water mix showed loss of 97% of benzene following an 800 krad dose and 88% following a 500 krad dose. At these loss rates, approximately 5 Mrad of electron beam irradiation is required to reduce concentrations from 100 g/l to drinking water quality (5 {mu}g/l). Since many waste streams are also inhabited by bacterial populations which may affect filtering operations, the effect of irradiation on those ...
Composites based on pure gypsum and polyester-styrene resin have been prepared using various doses of gamma radiation. Some physical properties of the prepared composites and the influence of irradiation dose on it have been studied as: compression strength, hardness, thermal decomposition temperature in nitrogen or oxygen, and the change in weight in aqueous solutions with different pH values. The glass transition temperature of the pure polymer and the composites increases with increasing the irradiation dose up to a plateau, and the glass transition temperature of the pure polymer is lower than that of the composites. The irradiation dose does not seem to affect the decomposition temperature of the pure polymer or the composites significantly and the decomposition temperature in presence of nitrogen is higher than that in presence of oxygen. Increasing the irradiation dose leads ...
Food-grade PVC and PVDC/PVC films containing 28.3% dioctyladipate (DOA) and 5.0% acetyltributylcitrate (ATBC) plasticizers, respectively, were brought into contact with olive oil and were irradiated with {gamma}-radiation [{sup 60}Co] at doses equal to 4 kGy and 9 kGy corresponding to `cold pasteurization`. Irradiation was carried out at 8-10 C and samples were subsequently stored at 4-5 C. Contaminated oil samples were analysed for DOA and ATBC at intervals between 7 h and 97 h of contact, using an indirect GC method. Identical non-irradiated (control) samples were also analysed for DOA and ATBC content. Results showed no statistically significant differences in migrated amounts of DOA and ATBC between irradiated and non-irradiated samples. Neither were differences observed between samples irradiated at 4 kGy and 9 kGy. This was supported by identical IR ...
Development of food preservation and processing techniques by radiation was performed. Gamma irradiation at 2-10 kGy is considered to be an effective method to control pathogenic bacteria in species including Escherichia coli O157:H7. Gamma irradiation at 5 kGy completely eliminated pathogenic bacteria in beef. Gamma irradiation at such doses and subsequent storage at less than 4 deg C could ensure hygienic quality and prolong the microbiological shelf-life resulting from the reduction of spoilage microorganisms. Gamma irradiation on pre-rigor beef shortens the aging-period, improves tenderness and enhances the beef quality. And, a new beef processing method using gamma irradiation, such as in the low salt sausage and hygienic beef patty was developed. Safety tests of gamma-irradiated meats(beefs: 0-5 kGy; porks: 0-30 kGy) in areas such as genotoxicity, acute ...
We used the recuperation effect (see also 'Recuperation of infrared stimulated luminescence of feldspars' in this issue) for investigating the connection between infrared- and greenlight-stimulated luminescence (IRSL and GLSL) of feldspars by performing a 'double-bleach recuperation' experiment. A diode system was used for infrared (IR) stimulation, and a filtered-light unit for greenlight (GL) stimulation. Powdered feldspar samples (2 mg each) of known chemical characterisation from a mineral collection were used. After beta-irradiation with 180 Gy and storage in the dark for several weeks feldspar aliquots were bleached down to a residual level of {approx}1% of the initial level, first with IR and subsequently with GL. For both stimulations, detection of the stimulated luminescence was carried out in the near ultraviolet region (around 260-360 nm, peaked at 340 nm). Other aliquots were bleached in reverse ...
We used the recuperation effect (see also 'Recuperation of infrared stimulated luminescence of feldspars' in this issue) for investigating the connection between infrared- and greenlight-stimulated luminescence (IRSL and GLSL) of feldspars by performing a 'double-bleach recuperation' experiment. A diode system was used for infrared (IR) stimulation, and a filtered-light unit for greenlight (GL) stimulation. Powdered feldspar samples (2 mg each) of known chemical characterisation from a mineral collection were used. After beta-irradiation with 180 Gy and storage in the dark for several weeks feldspar aliquots were bleached down to a residual level of #approx#1% of the initial level, first with IR and subsequently with GL. For both stimulations, detection of the stimulated luminescence was carried out in the near ultraviolet region (around 260-360 nm, peaked at 340 nm). Other aliquots were bleached in reverse order (1st GL, 2nd IR). These ...
The photoaffinity probes [#gamma#-"3"2P]2-azidoATP (2-N_3ATP) and [#alpha#-"3"2P]8-azido-ATP (8-N_3ATP) were used to investigate the binding of ATP to highly purified 2-5A synthetase. 2-N_3APT and 8-N_3ATP are substrates for 2-5A synthetase. In this study the authors show that 2- and 8-N_3ATP are competitive inhibitors of the enzymatic conversion of ATP to 2-5A. Ultravioletirradiation results in the photoinsertion of 2-N_3ATP and 8-N_3ATP into the enzyme. The covalent photoinsertion of [#alpha#-"3"2P]8-N_3ATP into the 2-5A synthetase is proportional to the inactivation of the enzyme as UV irradiation is increased. Photolabeling of 2-5A synthetase is saturated at 1.5 mM 2-N_3ATP and 2.0 mM 8-N_3ATP. Computer analysis of the curvilinear Scatchard plots of the 2-5A synthetase suggest the presence of high-affinity and low-affinity binding sites that may correspond to the acceptor and the 2'-adenylation sites of the enzyme. The ...
A nucleoside triphosphate binding site on calf thymus RNA polymerase II was identified by using photoaffinity analogues of adenosine 5'-triphosphate and guanosine 5'-triphosphate. Both radiolabeled 8-azidoadenosine 5'-triphosphate (8-N3ATP) and radiolabeled 8-azidoguanosine 5'-triphosphate (8-N3GTP) bound to a single polypeptide of this enzyme. This polypeptide has a molecular mass of 37 kilodaltons and an isoelectric point of 5.4. Ultraviolet (UV) irradiation was necessary for photolabeling to occur. In addition, no labeling occurred when the probe was prephotolyzed or when the enzyme was inactivated. Furthermore, photolabeling of the enzyme could be decreased by preincubation with natural substrates. To provide evidence that the radiolabeled polypeptide forms a part of the domain of the nucleoside triphosphate binding site, experiments were performed using unlabeled 8-N3ATP. Although this unlabeled analogue ...
We have investigated the correlation between V-shaped defect formation and the optical properties of AlGaN/(In)GaN multiple quantum wells (MQWs) grown under different growth conditions and then demonstrated the characteristics of fabricated ultraviolet (UV) light emitting diodes (LEDs). From the temperature-dependent photoluminescence (PL) measurement, the internal quantum efficiency for 300 K was obtained as 43.6% for a sample with a low density of V-defects in a MQW and 13.7% for a sample with a high density of V-defects. The carrier lifetime based on the time resolved PL measurement at room temperature was 0.32 ns for a sample with a high density of V-defects and 1.26 ns for a sample with a low density of V-defects. And we also found that the density of V-defects affected the external quantum efficiency and wall plug efficiency of the fabricated UV LEDs. (fast track communication)
Inhibition of photosynthesis by ultraviolet-A radiation (UV-A, 315-380 nanometers) was examined in three marine angiosperms: Halophila engelmannii Aschers, Halodule wrightii...Full Text Available
A study was carried out to determine optimum decontamination dose for a locally manufactured coconut cream powder. Samples were gamma irradiated (0-15 kGy) and ageing process was achieved using GEER oven at 60 deg. C for 7 days, which is equivalent to one-year storage at room temperature. Iodine value (IV), ranging from 4.8 to 6.4, was not affected by radiation doses and storage, however peroxide value and thiobarbituric acid (TBA) generally increased with radiation doses. In most samples, peroxide value (meq/kg) reduced after storage, whilst the TBA (mg malonaldehyde/kg), indicator for product quality, slightly increased. The sensory evaluation conducted using 25 taste panellists indicated that scores on odour, creamy taste and overall acceptance for all irradiated samples at more than 5 kGy were significantly lower (P<0.05) than the control. However, the panellists could not detect any significant differences among ...
The number and type of stem cells in spleen and bone marrow of mice were determined after exposure to a single dose of 150 R on day 6, to a single dose of 500 R on day 6 or day 9 or to a fractionated dose of 150 R + 350 R on day 6 and 9. The stem cells were assayed on the basis of colony forming units (CFU) in spleen and of incorporation of iododeoxyuridine in spleen and bone marrow of lethally irradiated host mice. During the first month of life, the number of stem cells in non-irradiated mice increases markedly in bone marrow and slightly in spleen. Irradiation causes a long-lasting depression in stem cells, particularly in bone marrow and affecting preferentially erythropoietic precursor cells. Following a dose of only 150 R, the number of CFU in bone marrow is still below control levels 24 days later. An exposure to 500 R fractionated between day 6 and 9 has a markedly greater effect on stem cells ...
A laminated material composed of glass cloth/polyimide film/epoxy resin will be used as an insulating material for superconducting coil of International Thermonuclear Experimental Reactor (ITER). In order to keep safe and stable operation of the superconducting coil system, it is indispensable to evaluate radiation resistance of the material, because the material is exposed to severe environments such as high radiation field and low temperature of 4 K. Especially, it is important to estimate the amount of gases evolved from the insulating material by irradiation, because the gases affect on the purifying system of liquid helium in the superconducting coil system. In this work, the gas evolution from the laminated material by gamma ray irradiation at liquid nitrogen temperature (77 K) was investigated, and the difference of gas evolution behavior due to difference of composition in the epoxy resin was discussed. It was found ...
Full text of publication follows: Low activation ferritic/martensitic steels are receiving a high priority in the European long term materials research. Although extensively investigated, the available experimental data do not cover all required parameter ranges and cannot unambiguously be used to produce hardening/embrittlement trend curves. Therefore, the main objective of this work is to provide a physically-based engineering model offering a rational to experimental observations. From the literature, experimental data were selected to establish a database that mainly consists of 8 to 9Cr-steels irradiated in the range of 50 to 600 deg. C up to 30 dpa and with a He-content up to 5000 appm. The database includes neutron and proton irradiations, He-implanted as well as B- and Ni-doped steels. Because of the difficulty of interpretation inherent to the Charpy impact test, only tensile data were considered. The difficulty stems from the large ...
Cassava is cultivated almost all over the world and it is considered one of the most important nutritious sources of calories in the human diet. Cassava is a viable food against starvation in several poor areas of the world because it is an extremely resistant culture and may reach satisfactory economical yield. We utilized vacuum packed industrialized cassava irradiated with 0,1 kGy, 3kGy and 5kGy and stored under refrigeration for 1, 21, 30 and 50 days. Our objective was to analyse the synergistic effect of vacuum packing, irradiation and refrigeration on the preservation of minimally processed cassava. The samples were analyzed for pH, acidity, weight, humidity, texture and color. The irradiation did not affect the chemical characteristics of the cassava. Neither the pH nor the acidity, the most relevant variables to verify deterioration in cassava, presented significant alterations during the period ...
Spice extracts under the form of essential oils were tested for their efficiency to increase the relative radiosensitivity of Listeria monocytogenes and Escherichia coli O157H7 in culture media. The two pathogens were treated by gamma-irradiation alone or in combination with oregano essential oil to evaluate their mechanism of action. The membrane murein composition, and the intracellular and extracellular concentration of ATP was determined. The bacterial strains were treated with two irradiation doses: 1.2 kGy to induce cell damage and 3.5 kGy to cause cell death for L. monocytogenes. A dose of 0.4 kGy to induce cell damages, 1.1 kGy to obtain viable but nonculturable (VBNC) state and 1.3 kGy to obtain a lethal dose was also applied on E. coli O157H7. Oregano essential oil was used at 0.020% and 0.025% (w/v), which is the minimum inhibitory concentration (MIC) for L. monocytogenes. For E. coli O157H7, a concentration of 0.006% and 0.025% ...
Elevation of zinc protoporphyrin (ZPP) levels in the blood has served as an indicator of lead poisoning and iron deficiency anemia for many years. We have discovered that sublethal doses of whole body irradiation with x-rays also elevates ZPP 2-3-fold over normal levels. The ZPP level does not begin to increase until days 12-14 postirradiation and peaks between days 18 and 20 before returning to normal levels between days 28 and 35. Increasing the radiation dose delays the onset of the rise in ZPP, but does not affect the magnitude of the elevation. At lethal doses, ZPP elevation is not observed. Neither of the two previously described mechanisms that cause elevations of ZPP, namely iron deficiency and inhibition of ferrochelatase, are responsible for the radiation-induced elevation of ZPP. The elevation of ZPP appears to be correlated with the recovery of the hematopoietic system from radiation injury.
Experiment was conducted to study the effect of gamma irradiation, growth retardants and coatings (coconut oil, mustard oil and liquid paraffin) on shelf life of winter guava fruits during storage. The results revealed that the superiority of coconut oil coating over other post harvest treatments. Physiological loss in weight (7.1%), marketable fruits retained over control (86.7%), total soluble solid (16.1%), ascorbic acid (195 mg/100 g pulp) and total sugar (10%) of fruit were positively influenced by coconut oil coating up to 12 days of storage. The treatment was found significantly effective in increasing the post harvest life of fruits for 12 days over control without adversely affecting the fruit quality. Coconut oil coating gave highest consumer acceptability while, maintaining suff...
The phenomenon of radiation blistering by helium ion bombardment has been the subject of extensive studies in recent years because of its technological importance in thermonuclear fusion devices and reactors. However, the mechanism of radiation blistering is still not well understood. There are two different models of blister formation: the gas-pressure model and the lateral stress model. The former model is, however, supported by many experimental observations, the prominent one is that of Evans and Eyre who observed blisters appearing on the front and rear surfaces of a thin wedge-shaped molybdenum foil irradiated by helium ions. Their experiment also indicates that the thickness of the irradiated specimen could be important in affecting the characteristics of blisters. With this in view, we have studied the development of blisters in thin foils of tantalum by 30 MeV ..cap alpha..-particle bombardment.
The phenomenon of radiation blistering by helium ion bombardment has been the subject of extensive studies in recent years because of its technological importance in thermonuclear fusion devices and reactors. However, the mechanism of radiation blistering is still not well understood. There are two different models of blister formation: the gas-pressure model and the lateral stress model. The former model is, however, supported by many experimental observations, the prominent one is that of Evans and Eyre who observed blisters appearing on the front and rear surfaces of a thin wedge-shaped molybdenum foil irradiated by helium ions. Their experiment also indicates that the thickness of the irradiated specimen could be important in affecting the characteristics of blisters. With this in view, we have studied the development of blisters in thin foils of tantalum by 30 MeV #alpha#-particle bombardment. (orig.).
Water repellency en the microstructure super-hydrophobic cured surface is important for research and industrial purposes. This microstructure film can be cured on polyethylene terephthalate PET surface by electron beam (EB) at different irradiation doses 10-100 kGy. The microstructure formulation composed from hydrophobic acrylate oligomer (EB 244) and monomer (SR 440). The irradiation induced cross linking of the prepared microstructure was proved by FTIR spectroscopy and the adhesion force by abrasion test. Some factors affecting the adhesion force of the prepared microstructure film such as oligomer/monomer composition ratio and the thickness of the microstructure cured film were studied. The contact angles (8) were measured on cured surfaces before and after adding the super hydrophobic nanoparticles (Zonyl 9361). The super-hydrophobic cured surface showed the self-cleaning property. The volume of water droplet ...
A series of measurements of O_3 yield in nuclear induced O_2 and O_2-SF_6 discharges created by bombardment with energetic particles from the "1"0B(n,#alpha#)"7Li reaction are reported. Continuous irradiation at dose ratios of 10"1"5-10"1"7 eV.cm"-"3.s"-"1 and pulsed irradiation (approx.10 ms FWHM) at a peak dose rate of approx.10"2"0 eV.cm"-"3.s"-"1 were conducted. At the lower dose rates, SF_6 addition generally increased the ozone yield, which at the high dose rates, SF_6 addition decreased the observed ozone concentration. A numerical model was developed and applied to experimental conditions. The steady-state ozone concentration was found to be limited by the reaction O_3"- + O_3 #-># 2O_2 + O_2"-. A simplified analytical model of steady-state conditions was used to predict model sensitivity to various parameters. In addition to dose rate effects, pressure and temperature effect on ozone production were discussed. The present study was ...
In light water reactors, austenitic stainless steels (SSs) are used extensively as structural alloys in reactor core internal components because of their high strength, ductility, and fracture toughness. However, exposure to high levels of neutron irradiation for extended periods degrades the fracture properties of these steels by changing the material microstructure (e.g., radiation hardening) and microchemistry (e.g., radiation-induced segregation). Experimental data are presented on the fracture toughness and crack growth rates (CGRs) of wrought and cast austenitic SSs, including weld heat-affected-zone materials, that were irradiated to fluence levels as high as {approx} 2x 10{sup 21} n/cm{sup 2} (E > 1 MeV) ({approx} 3 dpa) in a light water reactor at 288-300 C. The results are compared with the data available in the literature. The effects of material composition, irradiation dose, and ...
Irradiation with a single dose of 30 Grey on the basal regions of the lungs of Sprague-Dawley rats induced a peribronchial and alveolar inflammation. Infiltration of mast cells in the edematous alveolar interstitial tissue and also in the peribronchial tissue were characteristic features of the lesion. The appearance of mast cells was already seen 4 wk after irradiation and by weeks 6 to 8 there was a heavy infiltration. The staining properties suggested that they were connective tissue-type mast cells. The infiltration of mast cells was paralleled by an accumulation of hyaluronan (hyaluronic acid) in the alveolar interstitial tissue 6 and 8 wk after irradiation. The recovery of hyaluronan (HA) during bronchoalveolar lavage (BAL) of the lungs also increased at this time. Treatment with a mast cell secretagogue, compound 48/80, induced a distinct reduction of granulated mast cells in the alveolar tissue. Regular treatment ...
The reliability of outdoor radon concentration measurements using the track-etch technique is affected by the environmental conditions. Studies have been made to improve stability of nuclear tracks in detector material and to achieve a stable dosemeter response. A dosemeter was developed utilizing chemically etched MA-ND/alpha (CR-39) detector which is thermally insulated and protected against solar irradiation. The calibration showed that its response amounts to 0.21 {plus minus} 0.03 tracks m{sup -2}/Bqm{sup -3} day and was found to be in good agreement with theoretical prediction. (author).
Irradiation of the human body in diagnostic X-ray procedures results in different absorbed doses in the various body organs. A somatic dose index in formulated by applying the relative sensitivity of the human to each of the most important somatic effects and utilizing the absorbed dose in the affected organs. This quantity is used to convey a cumulative somatic impact and is computed for common radiographic views in diagnostic radiology as a function of beam quality for a nominal IR entrance exposure. Using typical X-ray beam qualities and exposures, the frequency of the various radiographic views that make up an examination and the frequencies of the various examinations in the national population, illustrative examples of the application of the somatic dose index are presented. (author).
This paper examines the correlation between mechanical properties and the density, phase, and hydrogen content of deposited alumina layers, and compares them to those of sapphire and amorphous alumina synthesized through ion-beam irradiation of sapphire. Alumina films were deposited using electron beam evaporation of aluminum and co-bombardment with O{sub 2}{sup +} ions (30-230 eV) from an electron cyclotron resonance (ECR) plasma. The H content and phase were controlled by varying the deposition temperature and the ion energy. Sapphire was amorphized at 84 K by irradiation with Al and O ions (in stoichiometric ratio) to a defect level of 4 dpa in order to form an amorphous layer 370 nm thick. Nanoindentation was performed to determine the elastic modulus, yield strength and hardness of all materials. Sapphire and amorphized sapphire have a higher density and exhibit superior mechanical properties in comparison to the deposited alumina films. ...
the cotton leaf worm, Spodoptera littoralis (boisd.) were irradiated with 100,150 and 200 Gy to induce inherited sterility. the effects of the tested doses applied to these pupae through three consequent fillial generations and the retarded influence on their F_1,F_2 and F_3 generations progeny were examined . irradiation of parental male induced damage to their daughter females ovaries. the overioles of females among P_1 ,F_1 and F_2 generations showed that the follicular epithelial cells appeared abnormal beside their limited separation from developing oocytes which became shrinked, semi absorbed or completely absorbed leaving vacuoles. the nurse cells were reduced or absent in some parts. damage was obvious through the first and second generations especially at 150 and 200 Gy. in the third generation, ovaries were not greatly affected
Comprehensive investigation has been made into the application of the polymerization hardening by radiation, particularly electron beam, to the composites of polymers and other materials. The report is divided into four parts, namely 1) characteristics and problems of the reaction of curing by radiation polymerization, 2) improvement of the bonding capability of high molecular weight materials, 3) bonding by radiation, and 4) composites made by the impregnation and polymerization hardening of monomers. The first part includes the effects of dose rate, temperature rise during the hardening, the peculiarity of electron beam irradiation at high dose rate, reaction environment and additive effects. Main conclusions are as follows: caution must be taken to the amount of residual double bonds because they affect the quality of hardened polymers; the polymerization hardening reaction at high dose rate cannot be analogized by that at low dose rate; and ...
In order to judge the potential fluorescent lamp applications of various low-pressure positive column discharges it is necessary to measure the absolute power emitted in the ultraviolet region of the spectrum. For rare-gas discharges the principle emission occurs in the vacuum ultraviolet so that it is difficult to measure the radiant emittance (power per unit area) of the resonance radiation by standard methods. Two independent techniques are discussed for measuring the radiant emittance of positive column discharges in the vacuum ultraviolet. These techniques are used to study xenon positive column discharges at the resonance wavelength of 147 nm. The first method relies on the measurement of the resonance level density by absorption techniques. The effective decay rate of the resonance level is then determined by the simulation of resonance radiation transport. These two quantities are combined to yield the radiant ...
... The addition of 0.5 pphr of fine thermal carbon black to the polymers gave good resistance to 500 hours of ultraviolet (UV) xposure in a Weather ...
instrument is shown in Figure 4-9 The incoming radiation is focused onto ...... An early rocket-borne ultraviolet spectrometer of the Ebert type by ...
Properties of photoconductive ultraviolet detectors fabricated on ZnO films were presented. Highly c-axis oriented ZnO films were grown on glass substrates by pulsed laser deposition. Ultraviolet photodetectors were fabricated based on metal-semiconductor-metal planar structures. The photoresponsivity and the quantum efficiency are much higher in the ultraviolet range than in the visible range, and the peak values are around 360nm. Photocurrent transients show that the detector has a large photocurrent with the peak value of 2.8mA, and a slow photoresponse with a rise time of 5min and a decay time of 7min. The response curve of the detector is fitted well with exponential curve. The large photocurrent should result from the both effects of the accumulation of conduction electrons and the d...
Ketamine-anesthetized Sprague-Dawley rats were exposed in H orientation to far-field 9.3-GHz continuous-wave (CW) and pulsed (2 microseconds 500 pps) radiofrequency radiation (RFR) at average power densities of 30 and 60 mW/sq. cm (whole-body average specific absorption rates of 9.3 and 18.6 W/kg, respectively). Irradiation was conducted to cyclicly increase colonic temperature from 38.5 to 39.5 C. Colonic, tympanic, and subcutaneous temperatures, ECG, blood pressure, and respiratory rate were continuously recorded during experimentation. At both power densities, the subcutaneous and tympanic temperature increases significantly exceeded the colonic temperature increase. At both exposure levels, heart rate increased significantly during irradiation and returned to baseline when exposure was discontinued. Blood pressure and respiratory rate did not significantly change during irradiation. There were no significant differences ...
In radiation processing of food, the product often has to be prepackaged to prevent microbial recontamination during and after irradiation. The packaging material is exposed to radiation during radiation processing and radiation stability is a key consideration in the selection of packaging materials. The effects of ionizing radiation on many food packaging materials at the dose levels recommended for food precessing can be minimized by selecting appropriate radiation resistant materials. It is important to select materials in which chemicals formed as a result of the radiation treatment do not migrate and interact with the food, affecting its organoleptic and toxicological aspects. It is also important to select materials in which the physical properties are not altered to the extent they cannot resist damage during commercial production, shipment and storage. Radiation treatment of food may be classified broadly into two categories: 1. ...
Female rats were given tritiated drinking water (3 microCi/ml) from 30 days before mating up to and throughout pregnancy. At this low dose, the course and the outcome of pregnancy were normal. The differences between newborn body and cerebral weights of the treated rats and those of control animals were on the borderline of significance. In contrast, cerebral DNA and cerebral protein were highly significantly lower. In 30-35% of the treated population the DNA and protein values were more than 2 standard deviations (SD) below the mean values for the control population. Thus the number of the progeny of the mothers exposed to tritiated water that were considered to have outstandingly low levels of DNA and protein was 14-17 times greater than in the control group. The irradiated population also had 3-5% of severely affected individuals with cerebral DNA and protein values more than 2 SD below the mean of the experimental population. However, even ...
Cockayne syndrome (CS) is a rare autosomal recessive disease, which shows diverse clinical symptoms such as photosensitivity, severe mental retardation and developmental defects. CS cells are hypersensitive to killing by ultraviolet (UV)-irradiation and defective in transcription-coupled repair. Two genetic complementation groups in CS (CS-A and CS-B) have been identified. We analyzed mutations of the CSA gene in 5 CS-A patients and identified 3 types of mutations. Four unrelated CS-A patients (CS2OS, CS2AW, Nps2 and CS2SE) had a deletion including exon 4, suggesting that there is a founder effect on the CSA mutation in Japanese CS-A patients. Patient CS2SE was a compound heterozygote for this deletion and an amino acid substitution at the 106th glutamine to proline (Q106P) in the WD-40 repeat motif of the CSA protein, which resulted in a defective nucleotide excision repair. Patient Mps1 had a large deletion in the upstream region including ...
Metagenomics projects based on shotgun sequencing of populations of micro-organisms yield insight into protein families. We used sequence similarity clustering to explore proteins with a comprehensive dataset consisting of sequences from available databases together with 6.12 million proteins predicted from an assembly of 7.7 million Global Ocean Sampling (GOS) sequences. The GOS dataset covers nearly all known prokaryotic protein families. A total of 3,995 medium- and large-sized clusters consisting of only GOS sequences are identified, out of which 1,700 have no detectable homology to known families. The GOS-only clusters contain a higher than expected proportion of sequences of viral origin, thus reflecting a poor sampling of viral diversity until now. Protein domain distributions in the GOS dataset and current protein databases show distinct biases. Several protein domains that were previously categorized as kingdom specific are shown to have GOS examples in other kingdoms. About ...
Depletion of stratospheric ozone increases irradiance of terrestrial ultraviolet (UV) radiation at short wavelengths, which may be harmful to the human health. To understand quantitatively the risks caused by increasing UV radiation to the Finnish population, the actual UV exposure of the population has to be assessed. It was shown that the snow reflection increases the UV exposure to the face and eyes particularly in the northern Finland. In 1993 exceptionally low ozone levels persisted up to the end of May, which resulted in a theoretical increase in the annual UV dose ranging from 8 % to 13 % in Finland. The maximal increase in the measured erythemally effective dose rate was 34 % on 23 April, when compared with the theoretical normal value. During this study exposure models have been developed. The models have been combined them with Green`s radiation transfer model to estimate annual facial UV doses received by different groups of Finnish ...
When a shortened enzymatic version of the Tetrahymena self-splicing intervening sequence (IVS) RNA is placed under catalytic conditions and irradiated at 254 nm, a covalent cross-link forms with high efficiency. The position of the cross-link was mapped by using three independent methods: RNase H digestion, primer extension with reverse transcriptase, and partial hydrolysis of end-labeled RNA. The cross-link is chemically unusual in that it joins two adenosines, A57 and A95. Formation of this cross-link depends upon the identity and concentration of divalent cations present and upon heat-cool renaturation of the IVS in a manner that parallels conditions required for optimal catalytic activity. Furthermore, cross-linking requires the presence of sequences within the core structure, which is conserved among group I intervening sequences and necessary for catalytic activity. Together these correlations suggest that a common folded structure permits cross-linking and ...
A rapid and accurate method for the direct simultaneous determination of nitrate and nitrite is proposed. The method is applied to the determination of nitrate and nitrite in rainwater and wastewater without preliminary separation. The determinations are performed by a CPA matrix method with ultraviolet spectrophotometric detection. The results obtained are in agreement with those obtained by conventional methods for the determination of nitrate and nitrite.
This paper deals with the electronic structure of ruthenium. Synchrotron radiation in the range from 15 to 45 eV and angle-resolved ultraviolet photoemission are used to map the energies of the electronic states. The Fermi surface of Ru is determined using angle-resolved ultraviolet photoemission spectroscopy. The experimental results are compared with calculated photoemission spectra obtained within the framework of the one-step model of photoemission. (author)
The absolute absorption of ozone in the midinfrared has been measured relative to 253.7-nm ultraviolet absorption to an accuracy of 1% using a Bruker Fourier transform spectrometer. These new results agree with previous measurements by diode laser measurements after the latter are corrected for more recent infrared calculations and ultraviolet cross sections. They also agree with a determination based on refractive index measurements in the infrared. 16 refs., 4 figs., 3 tabs.
Tetracycline is an antibiotic that absorbs ultraviolet light at 355 nm and preferentially binds to atherosclerotic plaque both in vitro and in vivo. Tetracycline-treated human cadaveric aorta was compared with untreated aorta using several techniques: absorptive spectrophotometry; and tissue uptake of radiolabeled tetracycline, which showed 4-fold greater uptake by atheroma than by normal vessel. In addition, intravenous tetracycline administered to patients undergoing vascular surgery demonstrated characteristic fluorescence in surgically excised diseased arteries. Because of tetracycline's unique properties, the authors exposed tetracycline-treated and untreated aorta to ultraviolet laser radiation at a wavelength of 355 nm. They found enhanced ablation of tetracycline-treated atheroma compared with untreated atheroma. The plaque ablation caused by ultraviolet laser radiation was twice as extensive in ...
The influence of low-frequency electromagnetic field irradiating by high-voltage transmission lines on signal transduction of cell in spleen cells of the rates have been studied by molecular-biology techniques. The spleen cells are extracted from skilled rates, which are exposed in the electromagnetic field of high-voltage transmission lines with 4000 V/m and 0.09-0.1 G about 400 days. The quantity or level of phosphorylation of signal transducer and activator of transcription (STAT3) in JAK-STAT signal transduction pathway of spleen cells, which are stimulated and unstimulated by IL-2, respectively, are detected by the immunoblotting and immunobiochemistry. The results show that the expression of phospho-STAT3 in spleen cell stimulated by IL-2 differ not from that in the unstimulated cell. The former is significantly large than the latter. This shows that signal transduction of cell is affected by this electromagnetic field. The spectra of ...
Ionizing radiation, mainly in the form of #gamma#-rays from the radioisotope cobalt 60, is being used increasingly for the inactivation of contaminants in cosmetic and toiletry preparations. The treatment is applied to the product in its final pack, and therefore, it is important to recognize that the properties of the packaging materials could be affected, particularly if high radiation doses are used. The stability of a wide range of materials is discussed. The nature and extent of chemical and physical changes in plastics very much depends on the presence of antioxidants and other additives, and on the environmental conditions during irradiation. Some useful information is available from research into the use of radiation for the preservation of food - many films and laminates have been cleared for use in the United States. The low radiation doses used for the control of contaminants in cosmetic products are quite unlikely to cause changes ...
In the Department of Radiology of Catholic University S. Cuore in Rome, a review was made of 342 CT examinations with a view towards optimizing the therapeutic planning in patients affected by bone metastases. All patients were submitted to radiological positioning and then to CT evaluation in order to assess the volume to be treated. In 224 cases it was not necessary to perform wide CT examination (3-5 standard tomograms being enough, 2 of which at the superior and inferior margins of the planned field). In the second group of 118 patients it was necessary to perform CT (serial axial scans) - increasing by 1-1.5 cm - up to the superior and inferior margins of the lesion. The existence of 2 types of lesions was confirmed: those involving mainly bony structures and those infiltrating the soft tissues. CT evaluation allowed the definition of the target volume to the real extension of the lesion in 14% of the whole of cases, while in the group of 118 cases studied ...
In experiments designed to detect new mutations affecting hemoglobin, we irradiated the male or female parent in reciprocal crosses of two mouse strains that differ in alleles at the hemoglobin (Hba, Hbb) loci as well as at five other specific loci. Offspring were analyzed for hemoglobin properties (electrophoretic pattern, solubility, crystal pattern), serum albumin differences, erythrocyte lysis, reticulocyte count, and external appearance. Five hemoglobin variants were found among the mutants. In three, the genetic contribution from the irradiated father was not expressed with regard to the #alpha#-chain; one carried a tandem duplication (the first known case in the mouse) involving Hbb; and one probably resulted from double nondisjunction of chromosome 7. The finding that major chromosome aberratios can mimic hemoglobin mutations indicates the need, in similar experiments, to follow F_1 screening with thorough ...
Seizures are a frequent sequela of impaired brain development and can be expected to affect more children with radiation-related brain damage than children without such damage. This report deals with the incidence and type of seizures among survivors prenatally exposed to the atomic bombing of Hiroshima and Nagasaki, and their association with specific stages of prenatal development at the time of irradiation. Fetal radiation dose was assumed to be equal to the dose to the maternal uterus. Seizures here include all references in the clinical record to seizure, epilepsy, or convulsion. Histories of seizures were obtained at biennial routine clinical examinations starting at about the age of 2 years. These clinical records were used to classify seizures as febrile or unprovoked (without precipitating cause). No seizures were ascertained among subjects exposed 0-7 weeks after fertilization at doses higher than 0.10 Gy. The incidence of seizures ...
Using the advantage that the projected range of ions in matter is sharply limited, a new technique for the production of three-dimensional microstructures has been developed. Based on the P-LIGA technique (Proton-Lithographie, Galvanoformung, Abformung) this process allows the generation of structures with surfaces of almost any shape having a root mean square roughness of about #lambda#/50 for visible light wavelengths. An ion beam with diameters between 2 and 50 #mu#m is directly writing the structures and the shape is varied by geometrical manipulation of the sample in three axes during the exposure. Practically, structures have been written using protons with an energy of 1.8 MeV in a provisional experimental setup with beam diameters of 10 and 50 #mu#m, respectively. After irradiation, the parts exposed were dissolved in a liquid developer without affecting the nonirradiated parts. The shape and the rms roughness of the resulting ...
We recently found that injection of 2 mCi of yttrium 90 (90Y; approximately 23,000 rads) into normal canine knees stimulated glycosaminoglycan (GAG) synthesis by femoral condylar cartilage. The present investigation was conducted to determine whether radiation affects cartilage metabolism directly. Rates of GAG synthesis and degradation in normal canine articular cartilage were studied following irradiation. Cultured synovium from the same knees was treated similarly, to determine the effects of irradiation on hyaluronic acid synthesis. Twenty-four hours after exposure to 1,000 rads, 10,000 rads, or 50,000 rads, 35S-GAG synthesis by the cartilage was 93%, 69%, and 37%, respectively, of that in control, nonirradiated cartilage. The effect was not rapidly reversible: 120 hours after exposure to 50,000 rads, GAG synthesis remained at only 28% of the control level. Autoradiography showed marked suppression of 35S uptake by ...
The role of radiation therapy in local tumor control and decreased incidence of pulmonary metastasis is reported in 271 patients who were entered into the Intergroup Ewing's Sarcoma Study with more than one year follow-up and on whom all radiotherapy records were reviewed. The majority of the patients were irradiated to the primary tumor with doses of 4500 to 6500 rad in five to six weeks in combination with systemic administration of three drugs (vincristine, actinomycin-D and cyclophosphamide) or four drugs (vincristine, actinomycin-D, cyclophosphamide and adriamycin). One of the groups of patients was treated with three drugs and bilateral pulmonary irradiation (1500 rad, uncorrected dose, in two weeks). Preliminary analysis shows an overall local primary tumor control of 89%. Patients with lesions in the pelvis had a local failure rate of 17% (9 of 52) and in the humerus 23% (7 of 31). Factors affecting local ...
Full text: The general population is daily exposed to chronic, low doses of ionizing radiation (IR) from both natural and artificial sources. The biological consequences of acute, high dose IR exposure can be readily determined; however, the nature and significance of low dose, low dose-rate IR effects are still the subject of debate. Confounding the issue, are the phenomena collectively referred to as the Radiation-induced Bystander Effect (RIBE). The RIBE describes a collection of in vitro observations that suggest the presence of a soluble, transmissible factor(s) released from irradiated cells that can induce a biological response in un-irradiated cells. The induction, nature and magnitude of the RIBE varies between cell culture systems, radiation sources and end-points measured. Efforts to confirm the presence of the RIBE in vivo have been confined to in vivo-like culture systems and limited work with tumour and bone-marrow transplantation ...
Diel vertial migrations of the marine dinoflagellates Gonyaulax polyedra Stein and Ceratium furca (Ehr.) Clap. et Lachm, were followed in a laboratory tube (2.02 m x 0.25 m) under a 12:12h light:dark cycle. The effects of temperature stratification, two levels of surface irradiance and nitrogen depletion on patterns of vertical migrations were examined. At temperatures between 22 to 26/sup 0/C with small temperature gradients, both species migrated at a rate of 0.7 to 1.0 mh/sup -1/. Steeper thermoclines (ca. 0.8/sup 0/C 0.1 m/sup -1/) with temperatures below ca. 20/sup 0/C caused a marked decrease in swimming speed which resulted in accumulations of cells in these thermocline regions. Under conditions of nutrient sufficiency both algae migrated into the surface layers at irradiance values of over 1000 ..mu..E m/sup -2/s/sup -1/. Increasing nitrogen depletion caused the downward migration of both algae to commence progressively earlier in the ...
The main aim of any food irradiation treatment is to guarantee the best safe quality of the products, reducing the spreading risk ("cross-contamination") for several food-associated diseases. Actually, over 40 countries provide clearances for the treatment of about 45 different types of foodstuffs. EU has to homogenise the situation within the associated States. With the European directive 1999/2/EC Italy, as other EU countries, already has brought into force their regulations to comply. The current Italian regulation on irradiation treatment of foodstuffs is referred since 1996 as follows: a) potatoes, onions and garlic; b) spices, herbs and condiments microbial. The new (April 2001) Italian law allows the possibility to ask for special permission of treatment for other foodstuff which is possible to treat in other E.U. countries. Large majority of foods are submitted to irradiation treatment after they have been packaged. ...
In order to gain an overall picture of the genetic effects of an increased level of background radiation it is necessary to study the results of protracted exposures to embryonic and immature germ-cell stages as well as to stages found in the mature organism. For this purpose, litters produced by female mice, kept in a 10 or 20 rad/day /sup 60/Co ..gamma..-irradiation field, were kept in the same fields from conception until about 60 days later, having absorbed doses of 526 and 1078 rad respectively. Tests on exposed female offspring showed them to be sterile. Eight weeks after removal from the gamma field, mean testis masses of males in the 20 rad/day series were only half normal but those receiving 10 rad/day were little affected. Frequencies of translocations in spermatocytes at diakinesis/metaphase I were only slightly increased in the exposed series, differences not being significant. Estimated rates of translocation induction were around ...
Each of the three cysteine residues in the Escherichia coli RecA protein was replaced with a number of other amino acids. To do this, each cysteine codon was first converted to a chain-terminating amber codon by oligonucleotide-directed mutagenesis. These amber mutants were then either assayed for function in different suppressor strains or reverted by a second round of mutagenesis with oligonucleotides that had random sequences at the amber codon. Thirty-three different amino acid substitutions were obtained. Mutants were tested for three functions of RecA: survival following UV irradiation, homologous recombination, and induction of the SOS response. It was found that although none of the cysteines is essential for activity, mutations at each of these positions can affect one or more of the activities of RecA, depending on the particular amino acid substitution. In addition, the cysteine at position 116 appears to be involved in the ...
Abstract Background and Purpose: During laser lithotripsy, working instruments are often in close proximity to the distal fiber tip and may be damaged accidentally or even intentionally. The aim of this study was to compare the amount of damage to a standard guidewire and the nitinol wires of endourologic retrieval baskets that were affected by three different clinically available laser systems. Materials and Methods: The impact of pulsed laser irradiation on a standard hydrophilic guidewire and a retrieval basket were investigated. One infrared (IR) laser system (holmium:yttrium-aluminum-garnet [Ho:YAG]: ????=???2100???nm) and two laser systems emitting light in the visible (VIS) spectral range (frequency-doubled double-pulse neodymium:YAG [FREDDY]: ????=???532???nm/1064???nm and flashl...
We consider the evolution of binary systems formed by a Supermassive Black Hole (SMBH) residing in the center of a galaxy or a globular cluster and a star in its immediate vicinity. The star is assumed to fill its Roche lobe, and the SMBH accretes primarily the matter of this star. The evolution of such a system is mainly determined by the same processes as for an ordinary binary. The main differences are that the donor star is irradiated by hard radiation emitted during accretion onto the SMBH; in a detached system, nearly all the donor wind is captured by the black hole, which strongly affects the evolution of the semi-major axis; it is not possible for companions of the most massive SMBHs to fill their Roche lobes, since the corresponding orbital separations are smaller than the radius ...
A large variety of microwave producing devices are used in contemporary naval communications and weapons systems. Public and scientific concern about potential biological effects of microwave irradiation such as produced by these various devices requires documentations of such effects. Currently, the only well documented direct effect of microwaves is heating of the exposed organism. The present report is of a series of studies whose aim was to explore several microwave frequencies and their effect on performance and simultaneously to investigate the relationship to core heating in the exposed animals. Three difficult sized species of animals were used so that generalization to larger animals could be made. Rats, squirrel monkeys, and rhesus monkeys showed consistent effects of 60-minute exposures to microwaves when their body temperatures were increased at least 1 C above baseline temperatures. Performance was not reliably affected when body ...
Microstructural analyses by advanced metallographic techniques were conducted on mockup welds and a cracked BWR core shroud weld fabricated from Type 304L stainless steel. heat-affected zones of the shroud weld and mockup shielded-metal-arc welds were free of grain-boundary carbide, martensite, delta ferrite, or Cr depletion near grain boundaries. However, as a result of exposure to welding fumes, the heat-affected zones of the welds were significantly contaminated by fluorine and oxygen which migrate to grain boundaries. Significant oxygen contamination promotes fluorine contamination and suppresses classical thermal sensitization, even in Type 304 steels. Results of slow-strain-rate tensile tests indicate that fluorine exacerbates the susceptibility of irradiated steels to intergranular stress corrosion cracking. These observations, combined with previous reports on the strong influence of weld flux, indicate that oxygen ...
Microstructural analyses by several advanced metallographic techniques were conducted on austenitic stainless steel mockup and core shroud welds that had cracked in boiling water reactors. Contrary to previous beliefs, heat-affected zones of the cracked Type 304L, as well as 304 SS core shroud welds and mockup shielded-metal-arc welds, were free of grain-boundary carbides, which shows that core shroud failure cannot be explained by classical intergranular stress corrosion cracking. Neither martensite nor delta-ferrite films were present on the grain boundaries. However, as a result of exposure to welding fumes, the heat-affected zones of the core shroud welds were significantly contaminated by oxygen and fluorine, which migrate to grain boundaries. Significant oxygen contamination seems to promote fluorine contamination and suppress thermal sensitization. Results of slow-strain-rate tensile tests also indicate that fluorine exacerbates the ...
Mechanisms that govern transport, accumulation and toxicity of persistent pollutants at interfaces in aquatic ecosystems were the foci of this thesis. Specific attention was paid to humic substances, their occurrence, composition, and role in exchange processes across interfaces. It was concluded that: The composition of humic substances in aquatic surface microlayers is different from that of the subsurface water and terrestrial humic matter. Levels of dissolved organic carbon (DOC) in the aquatic surface microlayer reflect the DOC levels in the subsurface water. While the levels and enrichment of DOC in the microlayer generally show small variations, the levels and enrichment of particulate organic carbon (POC) vary to a great extent. Similarities exist between aquatic surface films, artificial semi-permeable and biological membranes regarding their structure and functioning. Acidification and liming of freshwater ecosystems affect DOC:POC ratio and humic ...
The interference of hyperthermia and ionizing radiation, respectively, with the effects of capric (10:0), lauric (12:0), myristic (14:0), oleic (cis-18:1) and elaidic (trans-18:1) acids on the osmotic resistance of human erythrocytes was investigated. The results are summarized as follows: (A) not only at 37 degrees, but also at 42 and 47{degrees}C lauric acid (12:0) represents the minimum chain length for the biphasic behaviour of protecting against hypotonic hemolysis at a certain lower concentration range and hemolysis promotion at subsequent higher concentrations; (B) with increasing temperatures the protecting as well as the hemolytic effects occur at lower concentrations of the fatty acids; (C) the increase of temperature promotes the extent of hemolysis and reduces the extent of protection against hypotonic hemolysis; (D) Gamma-irradiation of erythrocytes selectively affects the concentration of oleic acid at which maximum protection ...
This volume presents the collations tables of a six volume comparative epidemiological survey of the effects of low level radiation dose. Data are collated for the effects observed in the following irradiated groups:- Preconception irradiation, intra-uterine irradiation, childhood irradiation, adult irradiation. (UK).
A 253.7-nm ultraviolet light with an intensity of 1,100 microW/cm2 was tested for its germicidal activity against contact lenses and storage solutions contaminated with various corneal pathogens. The exposure time necessary to reduce a concentration of organisms from 10(6)/ml to less than 10/ml was 30 seconds for Staphylococcus aureus, 60 seconds for Pseudomonas aeruginosa, and 84 seconds for Candida albicans. The time necessary to sterilize a suspension of 10(4)/ml Acanthamoeba polyphaga was less than three minutes with this technique. Four brands of soft contact lenses were exposed to ultraviolet light for over eight hours without changing their appearance, comfort, or refraction.
Since 1979, scientists and engineers at the Los Alamos National Laboratory have designed, constructed, and operated a radio-frequency (RF) linac free-electron laser (FEL) at wavelengths from 9 to 45 /mu/m. Coupled with success of other research centers investigating wavelengths from the visible to far-infrared, Los Alamos is now proposing a vacuum-ultraviolet and soft x-ray (referred to henceforth as extreme ultraviolet, (XUV)) FEL oscillator/Self-Amplified Spontaneous Emission amplifier with beam energies ranging from 100 MeV to 1 GeV. This paper will focus on the first milestone of the proposed Los Alamos XUV project, i.e., a 250-MeV linac with approximately 50 mA of average current, producing photons with wavelengths below 1000 /angstrom/. 3 refs., 3 figs.
A semiquantitative assay was developed and used to measure the effects of immune responses against 16 independent non-H-2 antigenic loci on erythropoietic stem cells. The assay compares repopulation in genetically anemic WBB6F1-W/Wv recipients that have normal immune responses, and in lethally irradiated WBB6F1 +/+ mice whose immune responses are suppressed by the irradiation. The differences in repopulating ability between these two types of recipients measure how immune responses affect erythropoietic stem cells. Stem cell repopulating abilities for the cells with antigens specified by the Thy-1, H-1, H-24, Ly-1, H-37, and H-17 loci were affected slightly, if at all. Repopulating abilities were moderately reduced by responses against antigens specified by H-15, 16, Ea-2, and Ly-2, 3 loci, and against the differences between the B6 and B10 genotypes, although marrow of these types cured W/Wv ...
I report on some recent work done in collaboration with E. de Rafael on the connection between ultraviolet renormalons in QCD and Nambu-Jona-Lasinio-like Lagrangians as its effective description at low energies. (orig.)
Oct 2, 2007 ... The Payload combines some of the most sensitive particle sensors .... provide state-of-the-art measurements of incoming x-ray, ultraviolet, .... It will be launched into a low-Earth orbit on a Delta 7320 rocket in September 2004. ...
Sunbed use is associated with increased risk of melanoma. Younger people might be more susceptible to the carcinogenic effects of ultraviolet radiation. We investigated the association between...Full Text Available
Experiments on Xanthium leaf discs were carried out to determine whether concomitant photoreactivation could be detected and if so, to compare its effects with photoreactivation due...Full Text Available
The ultraviolet photoelectron spectra of benzoic acid and 20 of its derivatives are presented. The low-energy regions of these spectra are deconvoluted and assigned using chemical substitution effects. 5 figures, 3 tables.
Properties of photoconductive ultraviolet detectors fabricated on ZnO films were presented. Highly c-axis oriented ZnO films were grown on glass substrates by pulsed laser deposition. Ultraviolet photodetectors were fabricated based on metal-semiconductor-metal planar structures. The photoresponsivity and the quantum efficiency are much higher in the ultraviolet range than in the visible range, and the peak values are around 360 nm. Photocurrent transients show that the detector has a large photocurrent with the peak value of 2.8 mA, and a slow photoresponse with a rise time of 5 min and a decay time of 7 min. The response curve of the detector is fitted well with exponential curve. The large photocurrent should result from the both effects of the accumulation of conduction electrons and the decrease of the barrier height between crystallites. The relaxation time constant {tau} obtained from the curve fitting represents the ...
Properties of photoconductive ultraviolet detectors fabricated on ZnO films were presented. Highly c-axis oriented ZnO films were grown on glass substrates by pulsed laser deposition. Ultraviolet photodetectors were fabricated based on metal-semiconductor-metal planar structures. The photoresponsivity and the quantum efficiency are much higher in the ultraviolet range than in the visible range, and the peak values are around 360 nm. Photocurrent transients show that the detector has a large photocurrent with the peak value of 2.8 mA, and a slow photoresponse with a rise time of 5 min and a decay time of 7 min. The response curve of the detector is fitted well with exponential curve. The large photocurrent should result from the both effects of the accumulation of conduction electrons and the decrease of the barrier height between crystallites. The relaxation time constant #tau# obtained from the curve fitting represents the ...
BackgroundChildhood is a high risk time for ultraviolet induced skin damage as this age group has more time and opportunity to be outdoors in the sun. Children in Africa with the...Full Text Available
Ultraviolet (UV) screens are increasingly used as a result of growing concern about UV radiation and skin cancer; they are also added to cosmetics and other products for light stability. Recent data...Full Text Available
BackgroundPreclinical studies indicate that the enzyme cyclooxygenase 2 plays an important role in ultraviolet-induced skin cancers. We evaluated the efficacy and safety of celecoxib,...Full Text Available
This work deals with a rational vision of stratospheric ozone including the threats on ozone layer, the verifications and the fears. After a recalling on the ozone layer history, the authors treats the question of the ultraviolets particularly the beneficial effects. Then an explanation of the ozone layer decrease is given. (O.L.). 29 refs., 6 figs.
Described herein are the results of the FY1994 research program for structural defects of silicon-based amorphous materials for solar cells. The study on light generation defects of the a-Si:H system and rejuvenation process by annealing establishes the effects of light irradiation time on changed neutral dangling bond density as a result of light irradiation at varying temperature of 77K, room temperature and 393K. The study on annealing to rejuvenate light generation defects of various types of a-Si-H systems establishes the activation energy distribution with respect to annealing to remove light-induced defects, showing that hydrogen affects the distribution of light-induced defects. The study on decaying process of light-induced ESR for undoped and N-doped a-Si:H systems observes the decaying process of light-induced ESR, after light is cut off, extending for a period of several seconds to several hours at 77K for the ...
The changes in quality of irradiated spices, i.e., nutmeg (Myristica fragrans), black pepper and white pepper (Piper nigrum) stored in different indigenous packaging materials were evaluated. Packaging materials used were tin cans; tin can lined with polypropylene film, tin can lined with wrapping paper, woven polypropylene bag and woven polypropylene bag lined with polypropylene film. Packaging in woven polypropylene bag could cause significant changes in a_w-values and moisture contents of the spices. In the tin can, no significant change was found during storage. By applying a polypropylene film liner inside the plastic bag, the changes could be retarded. The other parameters observed, i.e. total plate count, total mould and yeast count and organoleptic scores of the samples were not significantly affected by the packaging method. A dose of 5 kGy could reduce the microbial load of the spices by about 2-3 log cycles. A significant decrease in ...
The present work studies the fecundity, egg batching and mating of normal females of Earias Insulana Boisd. crossed with males irradiated as 24 h adult moths with two doses (80 and 100 Gy.) of gamma radiation. The male progeny were out bred or inbred with untreated individuals for two successive generations F_1and F_2 and their progeny was observed for any inherited deleterious effects on reproduction. The female fecundity and egg hatch were significantly reduced among P1,F1 and F2 generations by increasing the dosages applied to P_1 males as compared with the untreated control. The percentage of mating of P_1 females was significantly reduced at the two doses as compared to the untreated control. The average number of spermatophores per mated female was reduced among P_1,F_1 and F_2 generations when parental males were irradiated with 100 Gy. The larval and pupal mortality a,o mg F_1, F_2 and F_3 generations was high and dose dependent. The ...
The chemical fixation of tritium in stearic acid followed by embedding the tritiated stearic acid into an epoxy resin proved to be a good method for permanent waste disposal of tritium gas. Tc-126 and Tc-136 hardener were used for this purpose. The polymerization temperature of the polymer products was found to be highly decreased by adding stearic acid and slightly decreased by adding stearic acid or by raising the temperature of the leachant medium and slightly decreased by irradiation. On the other hand, small improvement in the compressive strength of the polymer products was achieved by adding silica powder. The polymer product showed high flame points above 573 K although it contains stearic acid. DTA and TG analysis indicate that the thermal stability of polymer products containing stearic acid and silica powder is better than samples containing only stearic acid. Stearic acid was found to possess good resistance to irradiation and the ...
Three ternary austenitic alloys (Fe-15Cr-25Ni, Fe-15Cr-25Ni-0.04P, Fe-15Cr-45Ni in both annealed and cold worked conditions) were irradiated at 465 C to 0.15, 0.28, and 0.42 dpa at above core position in the Fast Flux Test Facility utilizing the Materials Open Test Assembly to study the separate and synergistic effects of He/dpa ratio, phosphorus addition, nickel content and cold work level on microstructural evolution and hardening. The helium/dpa ratio was varied by isotopic doping with "5"9Ni to enhance the production rate of helium. The helium production rate was evaluated to be 62 appm He/dpa in the "5"9Ni-doped specimens and 0.26 appm He/dpa in the undoped specimens. Transmission electron microscopic examinations revealed that alloy composition affected significantly the evolution of microstructure during irradiation. Phosphorus addition prevented the formation of Frank loops through the precipitation of phosphide. ...
Full text: DNA rearrangement events leading to chromosomal aberrations are central to ionizing radiation-induced cell death. Although DNA double-strand breaks are probably the lesion that initiates formation of chromosomal aberrations, little is understood about the molecular mechanisms that generate and modulate DNA rearrangement. Examination of the sequences that flank sites of DNA rearrangement may provide information regarding the processes and enzymes involved in rearrangement events. Accordingly, we developed a method using inverse PCR that allows the detection and sequencing of putative radiation-induced DNA rearrangements in defined regions of the human genome. The method can detect single copies of a rearrangement event that has occurred in a particular region of the genome and, therefore, DNA rearrangement detection does not require survival and continued multiplication of the affected cell. Ionizing radiation-induced DNA rearrangements were detected in ...
We report the corrected intercomparison of the World Radiometer Reference (WRR) irradiance scale and the Electrotechnical Laboratory (ETL) spectral irradiance scale. In addition, we confirm the intercomparison precision using the test facility where the irradiance of ETL 500 W standard lamp can be measured directly with the cavity radiometer. The results showed that the irradiance based on the WRR scale was 0.5-0.7% lower than the one based on the ETL scale
It needs accurate estimation of radiation level for verifying machinery and cable in Nuclear Power Plant. Therefore, in this study, we used ESR(Electron Spin Resonance) system for estimate dose of Alanine dosimeter. Alanine/ESR dosimetry, already known as a dosimetric method in medical and industrial field, was applied to estimate dose quantity at cable locations within a nuclear power plant as a part of equipment qualification program. Alanine/ESR dosimetry of absorbed dose range is 1 - 100 KGy. The alanine dosimeter is not significantly affected by temperature and fading is limited to 1% per year. The alanine dosimeters were fixed on the targeted cable or nearest position to measure dose quantity to get accurate value. Alanine dosimeters were scanned by commercially used two different ESR systems, e-scan and EMX series for alanine dosimeters. To estimate more accurate dose, two environmental correction factors, irradiation temperature and ...
Simple hydroxamic acids have been shown to have useful applications in an Advanced Purex process for the reprocessing of irradiated nuclear fuel. They are especially suited to the separation of neptunium (IV) from uranium (VI) by the selective formation of a hydrophilic complex with Np(IV). U(VI) extraction in to 30% tributyl phosphate is unaffected. However, they have also been shown to be very fast reducing agents for Np(VI). The timescales of the reduction have been defined under a range of typical Purex Process conditions although the accurate determination of the reaction kinetics was not possible due to the rapidity of the reaction. U(VI) was shown not to be reduced. Therefore, Np(VI) can be efficiently reductively stripped when solvent phase (30% tributyl phosphate in odourless kerosene) solutions of Np(VI) and U(VI) are contacted with aqueous phase hydroxamic acid solutions. The slow reduction of plutonium (IV) to Pu(III) has also been observed and this is ...
The preparation of wood-plastic combinations (WPC) using combined methods for curing intermediate products and final products is described. In the first step, impregnated wood was irradiated using doses of 1 to 10 kGy in the presence of chemical initiators of polymerization. Thereafter, curing of this partly cured impregnating mixture was accomplished in the wood at elevated temperatures with the aid of chemical initiators of polymerization. Impregnation mixtures based on unsaturated polyester resins and methyl methacrylate, and the wood species European Beech (Fagus silvatica) and Black Alder (Alnus glutinosa) were used. The results indicate that this method of preparing WPC allows substantially lower radiation doses to be used, i.e., doses in the range of 1 to 2.5 kGy. These doses gelatinate the impregnation mixture in the wood so that the subsequent curing by chemical polymerization initiators proceeds without the impregnation mixture flowing out of the wood, ...
The preparation of wood-plastic combinations (WPC) using combined methods for curing intermediate products and final products is described. In the first step, impregnated wood was irradiated using doses of 1 to 10 kGy in the presence of chemical initiators of polymerization. Thereafter, curing of this partly cured impregnating mixture was accomplished in the wood at elevated temperatures with the aid of chemical initiators of polymerization. Impregnation mixtures based on unsaturated polyester resins and methyl methacrylate, and the wood species European Beech (Fagus silvatica) and Black Alder (Alnus glutinosa) were used. The results indicate that this method of preparing WPC allows substantially lower radiation doses to be used, i.e., doses in the range of 1 to 2.5 kGy. These doses gelatinate the impregnation mixture in the wood so that the subsequent curing by chemical polymerization initiators proceeds without the impregnation mixture flowing out of the wood, ...
Optically stimulated luminescence (OSL) and thermoluminescence are observed in polycrystalline RbMgF3:Eu2+ after x-ray, ?-ray, or ? irradiation. The main electron traps are F-centers but there are other unidentified traps. The main hole traps at room temperature are probably Eu3+ and thermal or optical stimulation leads to electron-hole recombination at the Eu3+ site and Eu2+ emissions arising from 6PJ to 8S7/2 and 4f5d(Eg) to 8S7/2 transitions. We find that some of the electron traps can be emptied by infrared stimulation and all of the electron traps can be emptied by white light stimulation. The OSL dark decay is long and exceeds 5 days for traps that are emptied by white light stimulation after initial infrared bleaching. Our results show that this compound can be used as a radiation dosimeter for intermediate dose levels where the 87Rb self-dose does not significantly affect the dose reading.
The adverse effect of moisture diffusion on the properties of wood has been one of the main weaknesses of wood. Using a gamma irradiation method, wood-polymer composites have been produced which exhibit significant improvement in mechanical properties like compression, creep deformation and creep rupture particularly at high humidity. It has been thought that the impregnation of polymer into the wood has affected the moisture diffusion in the wood, so that its adverse effects on the mechanical properties has been reduced. In this report the apparent diffusion coefficients of a Ramin wood impregnated with varying amounts of polymethyl methacrylate (PMMA) were determined using a Fick's law approach. An initial linear relationship was found for impregnation of up to 70% PMMA, after which the diffusion coefficient levels off to a maximum value, for the three environmental relative humidity levels of 40, 60 and 90({plus minus}5)%. The ...
The adverse effect of moisture diffusion on the properties of wood has been one of the main weaknesses of wood. Using a gamma irradiation method, wood-polymer composites have been produced which exhibit significant improvement in mechanical properties like compression, creep deformation and creep rupture particularly at high humidity. It has been thought that the impregnation of polymer into the wood has affected the moisture diffusion in the wood, so that its adverse effects on the mechanical properties has been reduced. In this report the apparent diffusion coefficients of a Ramin wood impregnated with varying amounts of polymethyl methacrylate (PMMA) were determined using a Fick's law approach. An initial linear relationship was found for impregnation of up to 70% PMMA, after which the diffusion coefficient levels off to a maximum value, for the three environmental relative humidity levels of 40, 60 and 90(#+-#5)%. The phenomenon could be ...
The accurate prediction of local hot spot during normal operation is important to ensure core thermal margin in a very high temperature gas-cooled reactor because of production of its high temperature output. The active cooling of the reactor core determining local hot spot is strongly affected by core bypass flows through the inter-column gaps between graphite blocks and the cross gaps between two stacked fuel blocks. The bypass gap sizes vary during core life cycle by the thermal expansion at the elevated temperature and the shrinkage/swelling by fast neutron irradiation. This study is to investigate the impacts of the variation of bypass gaps during core life cycle as well as core restraint mechanism on the amount of bypass flow and thus maximum fuel temperature. The core thermo fluid analysis is performed using the GAMMA+ code for the PMR200 block-core design. For the analysis not only are some modeling features, developed for solid ...
The accurate prediction of local hot spot during normal operation is important to ensure core thermal margin in a very high temperature gas-cooled reactor because of production of its high temperature output. The active cooling of the reactor core determining local hot spot is strongly affected by core bypass flows through the inter-column gaps between graphite blocks and the cross gaps between two stacked fuel blocks. The bypass gap sizes vary during core life cycle by the thermal expansion at the elevated temperature and the shrinkage/swelling by fast neutron irradiation. This study is to investigate the impacts of the variation of bypass gaps during core life cycle as well as core restraint mechanism on the amount of bypass flow and thus maximum fuel temperature. The core thermo fluid analysis is performed using the GAMMA+ code for the PMR200 block-core design. For the analysis not only are some modeling features, developed for solid ...
Laser devices are currently in widespread use in particular by armed forces for different tasks. Electro-optical sensors as well as unprotected human eyes are extremely sensitive to laser radiation and can be permanently damaged from direct or reflected beams. Laser damage depends on the interaction between the laser beam and the atmosphere in which it traverses. The atmospheric conditions, including the range, terrain features, turbulence, and atmospheric particulates, may alter the laser's effect on different electro-optical devices and systems. When a laser beam passes through the atmosphere the optical turbulence affects the beam. As a result, temporal intensity fluctuations (scintillations) or spatial variations in intensity within a beam cross-section occur. Atmospheric scintillations pose a safety problem because an observer or sensor can be subjected to the risk of a localized irradiance (local focusing effect) much greater than that ...
The major part of the chapter 'Physical Properties' in concerned with, in addition to nuclear and atomic properties, the properties of the metal molybdenum. Due to the huge number of relevant papers, the present volume comprises only the first part of the metal properties, i.e. the crystallographic properties, the electronic structure, the lattice dynamics, and subsequently the mechanical and thermal properties. There are two small sections where the properties of the molecules, primarily Mo/sub 2/ and Mo/sub 6/, and of the vapor are described. The strength and some other mechanical properties have been frequently investigated to establish the change due to neutron irradiation, because this affects the durability of the fuel containers in nuclear reactors. For that purpose, changes in structure, texture, etc., due to irradiation had to be determined; the structural properties of nonirradiated samples also ...
The process of infrared multiple photon dissociation (IRMPD) of molecules is of great fundamental importance and has practical significance, such as isotope separation etc. Unfortunately, a clear insight into the process has been hindered by the bewildering array of important variables affecting MPD. The dissociation probability #gamma#(#phi#) i.e. the yield has been found to be a sensitive function of laser fluence #phi# along with numerous other parameters like laser frequency, gas pressure etc. We have shown that in single frequency IRMPD an accurate quantitative characterization of the dissociation probability can be adequately expressed by a 'power law' model with two fitting parameters namely critical fluence, #phi#c and multi photon order, m. This model was exploited in analysing our MPD results on various systems. However, the small isotope shift encountered in heavy elements and the sticking phenomenon observed in small light molecules restrict ...
Aerosols affect the radiative energy budget on both the regional and global scales. The wavelength-dependent aerosol optical depth (AOD) is a fundamental determinant of the amount by which extra-terrestrial incoming sunlight and outgoing terrestrial radiation are being attenuated in the atmosphere. The present study addresses the influence of local waste burning on aerosol characteristics, black carbon (BC) aerosol mass concentration and spectral solar irradiance using ground-based measurements over the tropical urban environment of Hyderabad, India. AOD has been observed to be maximum during burning days compared to normal days. Aerosol size spectra suggest bimodal distributions during pre-and post-burning periods and trimodal distributions during burning periods. Angstrom wavelength exponent estimated from spectral variation of AOD suggested dominance of accumulation mode particle loading during burning days compared to normal days. Diurnal ...
The core bypass flow in a prismatic very high temperature reactor (VHTR) is an important design consideration and can have considerable impact on the condition of reactor core internals including fuels. The interstitial gaps are an inherent presence in the reactor core because of tolerances in manufacturing the blocks and the inexact nature of their installation. Furthermore, the geometry of the graphite blocks changes over the lifetime of the reactor because of thermal expansion and irradiation damage. The occurrence of hot spots in the core and lower plenum and hot streaking in the lower plenum (regions of very hot gas flow) are affected by bypass flow. In the present study, three-dimensional computational fluid dynamic (CFD) calculations of a typical prismatic VHTR are conducted to better understand bypass flow phenomena and establish an evaluation method for the reactor core using the commercial CFD code FLUENT. Parametric calculations ...
The core bypass flow in a prismatic very high temperature gas-cooled reactor (VHTR) is one of the important design considerations which impacts considerably on the integrity of reactor core internals including operating fuels. The interstitial gaps are an inherent presence in the reactor core because of tolerances in manufacturing the blocks and the inexact nature of their installation. Furthermore, the geometry of the graphite blocks changes over the lifetime of the reactor because of thermal expansion and irradiation damage. The occurrence of hot spots in the core and lower plenum and hot streaking in the lower plenum (regions of very hot gas flow) will be affected by the bypass flow. In the present study, three-dimensional computational fluid dynamic (CFD) calculations of a typical prismatic VHTR are conducted to understand better the bypass flow phenomenon and establish the evaluation method in the reactor core using commercial CFD code ...
We present the results of a search for Extreme Ultraviolet emission in A4059, a cluster with an X-ray emitting cluster gas. Our analysis of Extreme Ultraviolet Explorer (EUVE) Deep Survey observations of this cluster shows that it is associated with diffuse EUV emission. Outside the central 2 arcmin radius the entire EUV emission detected is explained by the low energy tail of the X-ray emitting gas. Within the central 2 arcmin region of the cluster we find a deficit of EUV emission compared to that expected from the X-ray gas. This flux deficit is discussed in the context of the cluster's cooling flow. The results derived for A4059 are compared to EUVE results obtained for other clusters such as Coma, Virgo, A1795, and A2199. As part of the study we have carried out a detailed investigation of the stability of the EUVE Deep Survey detector background. Based on long integrations of blank sky over 27 months we disprove claims of substantial time ...
Existing test procedures for measuring and rating thermal performance require the determination of the angular response of collectors in order to account for nonnormal incident beam irradiance. Angular response measurements for four different types of collectors, each type tested by three different laboratories, are presented and analyzed. Substantial differences, both within and between laboratories, are reported for the same type collectors. An analysis of the measurement procedure shows that experimentally determined angular response parameters are subject to relatively large uncertainties. The problem results to a large extent from measuring collector efficiencies at non-normal incident angles where measurement uncertainty is of the same order of magnitude as the efficiency reduction attributable to these off-normal angles. Other factors which can affect angular response measurements and the method of correlating results are also discussed. ...
Full text: Pigments possessing the ability to confer high solar reflectance have received considerable attention in recent years. The inorganic class of NIR reflective pigments are mainly metal oxides and are primarily employed in two applications: (i) visual camouflage and (ii) reducing heat build up. More than half of the solar radiation consists of near-infrared radiation (52%), the remaining being 43% visible light and 5% ultraviolet radiation. Over heating due to solar radiation negatively affects comfort in the built environment and contributes substantially to electrical consumption for air conditioning and release of green house gases. A pigment which has strong reflections in the NIR region (780-2500 nm) can be referred to as a 'cool' pigment. However, most of the NIR reflective inorganic pigments particularly yellow (eg. cadmium yellow, lead chromate, chrome titanate yellow etc.) contain toxic metals and hence their consumption is ...
Purpose Ultraviolet-B (UV-B) radiation can cause phototoxic macular injuries in young people who have been sunbathing but not sungazing and in welders. Welders have a reportedly increased risk of uveal melanoma. We analyze phakic and pseudophakic risks for solar and welding arc UV-B exposure. Design Optical radiation measurement, analysis, and perspective. Methods Spectral transmittances were measured for UV-transmitting, UV-blocking, and blue-blocking intraocular lenses (IOLs). The photoprotective performances of crystalline and intraocular lenses were analyzed using relevant epidemiologic and laboratory data and action spectra for acute retinal phototoxicity and melanoma photocarcinogenesis. Results Crystalline lens UV-B retinal protection is deficient in children and young adults, incre...
Metallic Zn films were deposited on glass substrates by electron-beam evaporation. ZnO films were synthesized by thermal oxidation of Zn metallic films in air. At the annealing temperature of 550 ?C, ZnO nanowires appeared on the surface, which mainly result from the decrease of oxidation rate. A ZnO ultraviolet photodetector was fabricated based on a metal-semiconductor-metal planar structure. The detector showed a large UV photoresponse with an increase of two orders of magnitude. It is concluded that promising UV detectors can be obtained on ZnO films by thermal oxidation of Zn metallic films. The ways of performing spectral response measurements for polycrystalline ZnO films are also discussed.
Thin film ultraviolet detectors based on hydrogenated amorphous silicon alloys are realized with different diode structures (PIN, NIP, PN, and NP). The PIN and NIP detectors exhibit higher sensitivity in the ultraviolet spectrum and a significant lower dark current in comparison to the PN or NP structures. The best detector performance was achieved with a 33 nm thick PIN diode. This detector shows a maximum of quantum efficiency of 36.3% at a wavelength of 310 nm. By varying the thickness of the semi-transparent Ag front contact the selectivity of the detectors with the quantum efficiency peak at 320 nm can be adjusted. Thus, the spectral sensitivity of the detector shifts from a broad UV to a selective UV-B spectrum. (orig.)
The auroras on Jupiter and Saturn can be studied with a high sensitivity and resolution by the Hubble Space Telescope (HST) ultraviolet (UV) and far-ultraviolet (FUV) Space Telescope spectrograph (STIS) and Advanced Camera for Surveys (ACS) instruments. We present results of automatic detection and segmentation of Jupiter's auroral emissions as observed by HST ACS instrument with VOronoi Image SEgmentation (VOISE). VOISE is a dynamic algorithm for partitioning the underlying pixel grid of an image into regions according to a prescribed homogeneity criterion. The algorithm consists of an iterative procedure that dynamically constructs a tessellation of the image plane based on a Voronoi Diagram, until the intensity of the underlying image within each region is classified as homogeneous. The computed tessellations allow the extraction of quantitative information about the auroral features such as mean intensity, latitudinal and longitudinal ...
Samples of vitamin D fortified orange juice obtained from retail food stores were analyzed for vitamin D3 content using a method developed by combining the best features of two AOAC methods. Detection by ultraviolet absorption at 265nm was compared to detection by selected ion monitoring (SIM) using atmospheric pressure chemical ionization (APCI) mass spectrometry (MS). Furthermore, an ion trap (IT) mass spectrometer was employed in a 'dual parallel MS' arrangement to simultaneously obtain qualitative APCI-ITMS data. The method was applied to 33 samples of 3 national American orange juice brands and 7 samples of 5 other American brands collected using a statistically designed sampling plan as part of the National Food and Nutrient Analysis Program to provide values for the USDA National Nu...
The Warm-Hot Intergalactic Medium (WHIM) arises from shock-heated gas collapsing in large-scale filaments and probably harbours a substantial fraction of the baryons in the local Universe. Absorption-line measurements in the ultraviolet (UV) and in the X-ray band currently represent the best method to study the WHIM at low redshifts. We here describe the physical properties of the WHIM and the concepts behind WHIM absorption line measurements of H I and high ions such as O VI, O VII, and O VIII in the far-ultraviolet and X-ray band. We review results of recent WHIM absorption line studies carried out with UV and X-ray satellites such as FUSE, HST, Chandra, and XMM-Newton and discuss their implications for our knowledge of the WHIM.
Among the numerous free-living amoebae (FLA) of soil and water habitats, certain species belonging to two genera Acanthamoeba and Naegleria are facultative parasites of man.They cause disease called primary amoebic meningoencephalitis where history of contact with water was recorded in most of the cases especially with Naegleria species. The present work aimed to search for presence of free-living amoebae in the water and trials for its control by Ultraviolet-radiation (UV-radiation). Samples from different water sources were examined for the presence of free-living amoebae. These samples were cultured on non-nutrient agar streaked with bacteria. Amoebae were detected and identified by means of their morphological characters. Twelve positive cases of one hundred and twenty examined samples could be detected. The positive samples were exposed to different doses of UV-radiation for different times.
A composition and method for encapsulating a photovoltaic device which minimizes discoloration of the encapsulant. The composition includes an ethylene-vinyl acetate encapsulant, a curing agent, an optional ultraviolet light stabilizer, and/or an optional antioxidant. The curing agent is preferably 1,1-di-(t-butylperoxy)-3,3,5-trimethylcyclohexane; the ultraviolet light stabilizer is bis-(N-octyloxy-tetramethyl) piperidinyl sebacate and the antioxidant is selected from the group consisting of tris (2,4-di-tert-butylphenyl) phosphite, tetrakis methylene (3,5-di-tert-butyl-4-hydroxyhydrocinnamate) methane, octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, and 2,2'-ethylidene bis(4,6-di-t-butylphenyl) fluorophosponite. The composition is applied to a solar cell then cured. The cured product contains a minimal concentration of curing-generated chromophores and resists UV-induced degradation.
As research for the chemical properties of lanthanide molecules in the dry system, electrochemical and ultraviolet-visible optical measurements on the chloride molten salt system have been conducted at Research Reactor Institute, Kyoto University. The reduction behavior of Ln(III)-Ln(0) and Ln(II) are measured on La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, and Yb by the cyclic voltammetry. The molar absorption coefficients of the f-f transition are measured by the measurement of ultraviolet-visible absorption spectra on Pr, Nd, Ho and Gd. From the comparison of the optical data between wet and dry systems, the characteristics of photon absorption are discussed in the molten salt. (H. Katsuta)
Irradiation response on the tensile properties of 9Cr-2W steels has been investigated following FFTF/MOTA irradiations at temperatures between 646 and 873 K up to doses between 10 and 59 dpa. The largest irradiation hardening accompanied by the largest decrease in the elongation is observed for the specimens irradiated at 646 K at doses between 10 and 15 dpa. The irradiation hardening appears to saturate at a dose of around 10 dpa at the irradiation temperature. No hardening but softening was observed in the specimens irradiated at above 703 K to doses of 40 and 59 dpa. Microstructural observation by transmission electron microscope (TEM) revealed that the dislocation loops with the a left angle 100 right angle type Burgers vector and small precipitates which were identified to be M_6C type carbides existed after the ...
The present invention concerns a device for peeling off activated concretes in processing for discarding a reactor of a nuclear reactor facility. The device comprises a gyrotron for generation microwaves, an irradiator for irradiating output microwaves, a reflection mirror for reflecting and converging the microwaves and irradiating them to a material to be irradiated and a first rotating means for rotating the irradiator and the reflection mirror in parallel with the axis of the gyrotron while maintaining the positional relation between the irradiator and the reflection mirror. When the position of the microwaves irradiated on concrete walls are moved in a circumferential direction and the central axes of the rotational axis and the material to be irradiated are aligned, then the intensity of the ...
Most superconductors are quite sensitive to irradiation defects. Critical temperatures may be depressed, critical currents may be increased, by irradiation, but other behaviours may be encountered. In compounds, the sublattice in which defects are created is of significant importance. 24 refs.
Growth at increasing continuous irradiance (at high nutrient nitrate) and nutrient nitrate concentrations (at high continuous irradiance) furnished increases in the in vivo and in...Full Text Available
Requirements for food packaging materials include whether there is any interaction between the food and the package during or after the irradiation, and whether as a result of the irradiation, volatile or leachable substances are released from the pack into the food. The performance of cellulose-based materials and plastic films under irradiation are discussed.
Pregnant females and newborn rats were exposed to a gamma irradiation of 150 rads. The stage of gestation at the time of irradiation varied from 14 to 21 days. The newborn rats were irradiated at 0, 1 and 2 days of age. The effect of irradiation of foetus and newborn rats depends on the age of the animal at the time of irradiation. This effect was specially important at the beginning of the foetal life. Neonatal mortality, growth of body weight and adult brain development were investigated. A modification of germ cell radiosensitivity during the period studied, was emphasized.
The effects of {alpha} particle irradiation on a passive film formed on a 304 type stainless steel are studied in situ. The experimental arrangement minimizes the radiolysis effects due to the electrolyte. Under irradiation, a modification of the electronic structure of the oxide layers is revealed by photo-electrochemistry and impedance measurements. The influence of irradiation on the corrosion resistance of the passive film is investigated. Comparing the rest potential and the breakdown potential respectively under and without irradiation, a drop in the passivity range under irradiation is shown. this is interpreted as a decrease in the corrosion resistance. (author).
The effects of #alpha# particle irradiation on a passive film formed on a 304 type stainless steel are studied in situ. The experimental arrangement minimizes the radiolysis effects due to the electrolyte. Under irradiation, a modification of the electronic structure of the oxide layers is revealed by photo-electrochemistry and impedance measurements. The influence of irradiation on the corrosion resistance of the passive film is investigated. Comparing the rest potential and the breakdown potential respectively under and without irradiation, a drop in the passivity range under irradiation is shown. this is interpreted as a decrease in the corrosion resistance. (author).
We present the results of a comprehensive study of the temperature dependences of the quantum efficiency for ultraviolet detectors based on GaAs, GaP and 4H--SiC Schottky structures, and on Si, GaAs p-n structures. For ultraviolet detectors based on Schottky structures, the quantum efficiency increases with increasing temperature for all photon energies, even including the semiconductor intrinsic absorption region. On the other hand, for ultraviolet detectors based on p-n structures, the quantum efficiency is practically temperature independent in the semiconductor intrinsic absorption region. The change in the quantum efficiency for the GaAs and Si detectors is less than 0.01% per degree. To explain the measurements, a variable trap occupancy model is presented. Subsurface imperfections of the semiconductor cause fluctuations in the profile of the conduction band and the valence band edges. In the presence of an electric ...
We present the results of a comprehensive study of the temperature dependences of the quantum efficiency for ultraviolet detectors based on GaAs, GaP and 4H--SiC Schottky structures, and on Si, GaAs p-n structures. For ultraviolet detectors based on Schottky structures, the quantum efficiency increases with increasing temperature for all photon energies, even including the semiconductor intrinsic absorption region. On the other hand, for ultraviolet detectors based on p-n structures, the quantum efficiency is practically temperature independent in the semiconductor intrinsic absorption region. The change in the quantum efficiency for the GaAs and Si detectors is less than 0.01% per degree. To explain the measurements, a variable trap occupancy model is presented. Subsurface imperfections of the semiconductor cause fluctuations in the profile of the conduction band and the valence band edges. In the presence of an electric ...
Spectrophotometric method, using a ratio-recording ultraviolet-absorption spectrophotometer, permits analysis of NaMBT in ethylene glycol-water solutions with high accuracy. It reduces analysis time, requires smaller samples, and is able to detect extremely small concentrations of mercaptobenzothiazole.
Epidermal gamma delta T cells (γδ T) and Langerhans cells (LC) are immune cells altered by exposure to ultraviolet radiation (UVB), a powerful stressor resulting in immune suppression....Full Text Available
The Rayleigh scattering length has been calculated for rare-gas liquids in the ultraviolet for the frequencies at which they luminesce. The calculations are based on the measured dielectric constants in the gas phase, except in the case of xenon for which measurements are available in the liquid. The scattering length mayplace constraints on the design of some large-scale detectors, using uv luminescence, being proposed to observe solar neutrinos and dark matter. Rayleigh scattering in mixtures of rare-gas mixtures is also discussed.
Governments around the world will soon make decisions on policies that could determine the fate of the ozone layer-the Earth's shield from harmful ultraviolet radiation. The Vienna Convention for the Protection of the Ozone Layer, signed on March 22, 1985, created a framework for scientific cooperation and information exchange that will form the basis for a protocol for controlling substances thought to threaten the ozone layer. As of mid-1987, 29 countries had signed the Convention, including the major producers and users of chlorofluorocarbons (CFCs), the most important of suspect chemicals.
Polyacrylonitrile films have been spin cast and pyrolyzed to produce thin (500--1500 A) carbon films. These films have higher electrical conductivities than films produced by other methods at similar temperatures. The conductivity can be varied by at least four orders of magnitude by changing the pyrolysis temperature. Ultraviolet, infrared, and Raman spectroscopies were used to investigate the chemical structure of the films during different stages of processing.
The non-invasiveness of autofluorescence technology may reduce sampling error and time delay for histopathology diagnosis. We establish biophotonic methods and guidelines to visualize and interpret early epithelial tissue changes that signify disease. Flexible and rigid fiber endomicroscopy instrumentation design parameters feasible for translation towards clinical use are in development.
The general n-point massless p-adic Feynman amplitude with arbitrary parameters of analytic regularization for each line is calculated. This result is presented in the form of a sum over hierarchies of a given graph. The structure of ultraviolet and infrared divergences of p-adic Feynman amplitudes is characterized and the star-triangle uniqueness identity in the p-adic case is derived. (orig.).
Pearls change their color to grey by #gamma#-ray irradiation. Grey densities were determined from darkness of pearl nuclei and thickness of the pearl layers. The densities are independent of both diameters of nuclei and pearls. The fading rate increases with increasing storage temperature. The rate of fading for irradiated pearls is lower than that for natural blue pearls. Comparison of photomicrographs (x 12) for pearls irradiated and then stored at room temperature for about 6 years revealed that their surfaces are not substantially different from the surfaces of unirradiated cultured pearls, indicating that #gamma# irradiation hardly gives rise to deterioration. #gamma#-Ray irradiation is a technique for coloration of pearls. Irradiated blue pearls seem to have resistivity to fading and to deterioration of the surface, if pearls have been ...
Dislocation priming measurements were performed in the kHz range in ASARCO copper. The samples and irradiation facilities are constructed so as to allow successive irradiation of samples both with electrons and gamma rays. The gamma rays were produced by stopping 2.8-MeV electrons in a gold target. The change of the type of irradiation could be achieved without any handling of the sample. Thus it is possible to detect rather small differences between the two types of irradiation. Recovery experiments at 400 deg K after 75 deg K irradiation and pinning rates during irradiation at 400 deg K and 75 deg K were made. (GE)
Changing cream pearls into bluish-grey by #gamma# ray irradiation is a technique in coloring of pearls. Irradiated pearls are similar in color to cultured blue pearls. The pearl layers hardly change their color but the nuclei change into dark brown by irradiation. Visible light (500 - 700 nm) penetrating the pearl layer is absorbed by dark brown nucleus. The intensity of reflecting light between 400 and 500 nm at pearl surface, therefore, becomes stronger than that between 500 and 700 nm; therefore color of irradiated pearls look bluish-grey. The density of bluish-grey color increases with increasing absorbed doses, but their luster at surface diminishes owing to the deterioration of the pearl layer by prolonged irradiation; high doses irradiation should be avoided. Irradiated pearls show no substantial fading of their color in a year and ...
Spices and packaging materials were exposed to gamma irradiation at a dose of 10 KGy. Luncheon was prepared with irradiated or non-irradiated spices. Prepared luncheon was packaged in irradiated or non-irradiated packaging materials. Packaged luncheon was treated with 2 KGy. Treated and untreated packaged luncheon were kept in a refrigerator (1-4 Centigrade) for 12 months. Microbiological, nutritive and chemical characteristics of luncheon were evaluated after processing and during storage; whereas, sensory quality was evaluated only after irradiation. Gamma irradiation decreased the microorganisms counts of spices, packaging materials and packed luncheon and increased the shelf-life of packaged luncheon products. No major differences in moisture, protein, fat, ph value, total acidity, lipid peroxide and volatile basic nitrogen were observed ...
Nanosized particles are important because of their unique properties, different from the bulk, which leads to their enhanced catalytic, photocatalytic and electronic properties. This work has dealt with three different nanoparticle systems in the context of three different aspects of nanoparticle properties: (a) photocatalytis (TiO2/metal) system, (b) luminescence (CdSe) (c) alloying (Pt-Ag and Pd-Ag). The initial photocatalytic enhancement obtained by adding noble metal on semiconductor nanoparticles, degrades as fast as in 15 minutes and questions their long-term performance. XANES measurements on such irradiated systems like TiO2/Au, TiO2/Pt, TiO2/Ir indicates a positive oxidation state of these noble metals which renders them as recombination centers for photo-excited electrons and explains the decreased photocurrent. The oxidation is caused by holes. The EXAFS results also indicate a change of the interfacial structure under the effect of ...
The method of treatment of uteral cancer by the brake irradiation of 25 MeV betatrone using original devices which promote forming therapeutic figured bunches is presented. The binding of the protective blocks with a special adjusting frame within the aperture of the diaphragm provided for low relative entering dose which is the advantage of high energy irradiation bunch. The use of the forming devices makes it possible to practice individual treatment and decrease the levels of irradiation doses for intact organs and tissues.
The potential market for irradiated chicken breasts was investigated using a mail survey and a retail trial. Results from the mail survey suggested a significantly higher level of acceptability of irradiated chicken than did the retail trial. A subsequent market experiment involving actual purchases showed levels of acceptability similar to that of the mail survey when similar information about food irradiation was provided.
Electron spin resonance (ESR) dosimetry of irradiated chicken legs is based on the additive dose or the calibration curve methods. In both cases the practical assumption is made that the behaviour of the chicken bone does not depend on factors such as temperature during irradiation, storage conditions and dose rate. So the aim of the present work was to investigate to what extent the above mentioned factors could influence the post-irradiation dose assessment using the ESR technique. (author).
A brief article examines the controversy over food irradiation regarding the wholesomeness of irradiated food, its microbiological safety, loss of vitamins and changes in flavour. The benefits of food irradiation are also outlined including the destruction of certain food-borne pathogens and the prolongation of the shelf-life of food by killing pests and delaying the deterioration process. (UK).
In conveyor type irradiators, the movement of conveyor and the product boxes is not there until the source is fully in the irradiation position. In case the conveyor system fails the source must automatically be returned to its shielded storage vault. The dose received by the product during the movement of the source from or to the shield becomes significant if the total dose to be received by the product is small. A study has been carried out for evaluating the transient dose received by onions in the POTON irradiator. The results of the study are discussed in this paper. (author)
AGROSTER Co irradiates food packaging material and some types of spices for the meat industry. The step by step strategy of AGROSTER has been very successful. In the last year, its gamma facility was used as much as possible to irradiate food items. The government of Hungary has recognized the benefit of this technology and has given financial assistance to establish a large commercial gamma irradiator in Budapest.
Electron microscopic observations of neutron irradiated Nb_3Sn revealed the presence of highly disordered regions of size approximately 35 A in a much less disordered matrix. This observation is shown to provide a means of explaining quantitatively many superconducting properties of irradiated A-15 compounds. In particular Tsub(c) of the irradiated materials could be easily predicted using the mathematical formulations developed for the proximity effect. (Auth.).
Effects of #gamma#-irradiation on synthetic polymers and paper used as packaging materials for irradiated food have been studied by NMR. Polystyrene, polybutadiene and some copolymers were studied before and after the #gamma#-irradiation treatment and in the presence or absence of antioxidants and stabilisers. In the absence of additives, the effect of #gamma#-irradiation on polystyrene is negligible even irradiating at high doses. In turn, the role of antioxidants and stabilisers is crucial in polybutadiene and butadiene-containing copolymers. Wood pulp paper was also studied by NMR. Preliminary measurements on #gamma#-irradiated wood pulp sheets show a shortening in the T_2 relaxation time component due to the bound water, i.e. some of the bound water is lost. (author)
Acute {gamma}-irradiation of rats at doses of 100 and 270 Gy stimulates lipid synthesis and changes the lipid composition of liver cell organelles. The content of cholesterol and cholesterol esters in microsomes increased at 100 Gy and decreased at 270 Gy, with total phospholipid content remaining unchanged. The lipid content in mitochondria decreased considerably 1 h after irradiation at 270 Gy. This change was significantly less pronounced 47 h later. Under chronic {gamma}-irradiation (0.129 Gy/day), cholesterol and cardiolipin in mitochondria increased. The changes in lipid content caused by acute irradiation are presumed to be related to activated synthesis of lipids in the liver. The modification of the lipid content of mitochondria observed in chronically irradiated rats may indicate that energy-metabolizing liver cell systems are involved in the adaptation to ...
The facilities in the Institute for Nuclear Research at Pitesti allow the testing, handling and examination of nuclear fuel and irradiated materials. The most important facilities are the TRIGA Steady State Research and Material Test Reactor and the Post-Irradiation Examination Laboratory (PIEL). The purpose of this work is to determine by post-irradiation examination, the behavior of CANDU fuel, irradiated in 14 MW TRIGA reactor. The fuel was irradiated in power ramp conditions. The results of post-irradiation examination are: - Visual inspection and photography of the outer appearance of sheath; - Profilometry (diameter, bending, ovality) and length measuring; - Determination of axial and radial distribution of the fusion products activity by gamma scanning and tomography; - Microstructural characterization by metallographic and ceramographic analyzes; - ...
The use of ionising radiation for the preservation of food has been under investigation for many years but has yet to receive worldwide acceptance. Although irradiation can be carefully controlled, it is generally accepted that the development of a test or tests for the detection of irradiated food would enhance consumer confidence and might help to enforce labelling regulations. The 2-alkylcyclobutanones are reported to be the only cyclic compounds formed as the products of the radiolysis of saturated and unsaturated triglycerides. The synthesis of 2-dodecylcyclobutanone (DCB) and 2-tetradecylcyclobutanone (TCB), which are formed from palmitic and stearic acid respectively following irradiation, has been carried out and using irradiated chicken meat as the model for a high-lipid containing food, both cyclobutanones have been extracted with hexane and then identified using gas chromatography/mass ...
This paper presents anew design concept for a gamma irradiation plant for the continuous processing of pumpable liquids. Typical applications of such a plant include: the irradiation vulcanisation of natural latex rubber; disinfection of municipal sewage sludge for agricultural use; sterilisation of liquids in the pharmaceutical and cosmetics industries; industrial processing of bulk liquids The authors describe the design and operation of the latex irradiator now operating on a small production scale in Malaysia and proposed developments. The design allows irradiation processing to be carried out under an inert or other gaseous environment. State-of-the-art computer control system ensures the fully automatic processing operation needed by industrial computers.
The mechanism of abrupt increase of the giant magneto impedance (GMI) ratio in the ion irradiated Co-based amorphous ribbon has been investigated. The grazing incident X-ray diffraction and transmission electron microscope were used to characterize the samples before and after ion irradiation. The GMI-ratio considerably increased in the ion irradiated samples and the GMI response showed strong dependence on the driving frequencies. The Barkhausen noise (BN) signals are increased for the Ar ion irradiated sample with dose of 1x10^1^7 ion/cm^2. The results are interpreted in terms of GMI variation associated with domain wall dynamics.
The post (neutron) -irradiation high-temperature tensile and creep-rupture properties, deformation and fracture characteristics of austenitic alloys, particularly solution annealed Type 316 steel, are surveyed and correlated with the damage structures developed as a function of irradiation temperature (and dose). The mechanisms proposed to explain the irradiation-induced changes in properties and behaviour are summarised. The factors responsible for the observed differences in the post-irradiation and 'in-reactor' creep-rupture properties and behaviour of an austenitic steel are discussed in terms of the helium gas and stress driven growth of small intergranular bubbles and the atom plating associated with their growth and coalescence. (author).
The most important and difficult part of materials research for fusion reactor is realized to be irradiation studies of fusion reactor materials. Irradiation studies of fusion reactor materials utilizing FFTF/MOTA, as one of Japan/U.S.A. Fusion Collaboration Programs, have important role to establish fundamental understanding of heavy irradiation effects on materials behavior and properties and to develop methods and technologies for advanced irradiation studies under fusion reactor environment. This paper briefly reviews the history, the state of the art, and the future of the FFTF/MOTA program. (author).
Studies on pupal irradiation of Earias vittella Fabricius, were undertaken to determine the optimum dose for sterile and competitive adults. Late pupae were irradiated with gamma radiation doses ranging from 150 to 300 Gy. Emerging adults were normal and without malformation. When males that emerged from irradiated pupae were crossed with normal female, fecundity as well as longevity was comparable to control, but there was drastic reduction in percent egg hatch in all the treatments. However, when females emerging from irradiated pupae were crossed with normal male, there was reduction in the fecundity as well as fertility and this effect was dose dependent. (author).
The nature of radicals in wood irradiated in vacuum was studied by ESR method. The decay rate of radicals changes in three temperature ranges. Long-lived radicals are very stable at 298"0K, at which the wood-plastics composite has often been studied. The number of radicals formed by irradiations shows fairly good agreement with the total number of radicals in each isolated wood component. The graft copolymerization of MMA to irradiated wood was also studied by means of ESR, and it was found that PMMA propagating radicals are formed in irradiated wood. These radicals are probably formed by the result of graft copolymerization of MMA of wood. (auth.).
With the mentioned method to analyse O-tyrosine with HPLC/fluorescence-detection, the irradiation of chicken meat can be determined in a simple and fast way. The formation of o-tyrosine is proportional to the applied dose but because it is also depending on the applied dose rate and the temperature during the irradiation, it is not possible to control the irradiation dose. Since unirradiated chicken can contain little amounts of o-tyrosine and to confirm some results, a second method is needed. Together with one of the other mentioned methods (analysis of the volatiles or esr-spectroscopy) it is possible to recognize irradiated chicken with a high security. (author).
We have shown that energy contamination introduced by ion beam deceleration technology that is used to increase the beam currents available for low energy boron implants, can affect fabricated junctions adversely. A 4 keV "1"1B beam is extracted and retarded by a potential of -3.5 keV for 0.5 keV "1"1B implantation, or by a potential of -3.8 keV for 0.2 keV "1"1B implantation. Intentional beam contamination was introduced by turning off the retarding potential to allow the 4 keV "1"1B ions to irradiate Si wafers directly. The percentage of contamination, at levels of 0.1%, 0.2% and 0.3% was introduced. Rapid thermal annealing of all the implanted samples was performed under N_2 ambient at 1050 deg. C for 1 s. The dopant tail profiles themselves are not significant if the contamination levels are low. However, the much higher damage level coming from high energy contamination increases the transient enhanced diffusion of "1"1B more than ...
Nineteen lesion mimic mutants (xsl1-19) of japonica rice Xiushui11 were obtained by ?-rays irradiation treatment. All mutants belonged to whole life lesion mimic. Lesion mimic of mutants didn't largen after tillering stage, leaves didn't wither, and no effect on the plants exsert spikes and seed. When the highest temperature in day exceeded 32 degree C in seedling stage, lesion mimic of all mutant expect xsl19 disappeared. Under 32 degree C, lesion mimic would appear gradually, and symptoms weren't inhibited by high temperature after 5 leaf stage. The plant heights of all lesion mimic mutants were 47.56-63.54 cm in the tillering stage, and that of CK was 83.75 cm; but the dwarf phenomenon of mutants only appeared before tillering stage, and didn't affect plant heights finally; the heading dates of mutants were the same to the CK, the ear length of all mutants were 9.43-15.19 cm, and that of CK was 16.41 cm; the total grain quantity per spike of ...
We present FIB-lithography methods for rapid and cost-effective prototyping of metal structures covering the deep-submicron- to the millimeter-range in a single lithography cycle. Focused ion beam (FIB) systems are widely used in semiconductor industry and research facilities for both analytical testing and prototyping. A typical application is to apply electrical contact to micron-sized sensors/particles by FIB induced metal deposition. However, as for E-beam lithography, patterning times for large area bonding pads are unacceptably long, resulting in cost-intensive prototyping. In this work, we optimized FIB lithography processing for negative and positive imaging mode to form metallic structures for large-areas down do the sub-100 nm range. For negative lithography features are defined by implanting Ga"+-ions into a commercial photo resist, without affecting the underlying structures by impinging ions. The structures are highly suitable for following lift-off ...
The central feature of the Fast Flux Test Facility (FFTF) is the fast test reactor (FTR), which is a liquid-sodium-cooled fast reactor providing high fast-neutron flux for irradiation testing of fuels and materials. The FTR also provides a means to develop breeder reactor core components and to gain reactor systems operating experience for future liquid-metal fast breeder reactors (LMFBRs). In the FTR core, there are 82 incore positions (within rows 1 through 6) available for driver fuel assemblies and/or test assemblies. In addition, there are three safety rods and six control rods located in rows 3 and 5, respectively, in the three symmetric core sectors. The FFTF has been successfully and continuously operated for more than 11 reactor cycles. For the first 8 cycles, the core loadings were composed of the mixed-oxide driver fuel assemblies and some test assemblies. These assemblies have an active core section of 91.5 cm with 15.2-cm upper and lower reflectors. ...
Ewing's sarcoma is a small round-cell tumor typically arising in the bones, rarely in soft tissues, of children and adolescents. Ewing's sarcoma has retained the most unfavorable prognosis of all primary musculoskeletal tumors. Prior to the use of multi-drug chemotherapy, long-term survival was less than 10%. The development of multi-disciplinary therapy with chemotherapy, irradiation, and surgery has increased current long-term survival rates in most clinical centers to greater than 50%. In addition, the preferred method of tumor resection has changed; limb salvage has nearly replaced amputation of the affected limb. Limb salvage procedures can be performed in place of amputation without compromising patient survival rates. Recent studies have revealed that the pathognomonic translocations involving the EWS gene on chromosome 22 and an ETS-type gene, which is most commonly the Fli1 gene on chromosome 11, are implicated in more than 95% of ...
CNPT-3 is the laboratory designation of a strain of bacteria that reproduces best at deep-sea pressures. It was isolated from a sample collected at a 5800 m depth of the Pacific Ocean. This isolation was achieved from a sample that had been retrieved without warning. This year we demonstrated that there are similarly behaving bacteria that can be isolated from samples even when retrieved with decompression. The purpose of this project was to define the temperatures and pressures over which CNPT-3 can exist and function. (1) At 2"0C CNPT-3 is eurybathic from about 1000 to 6500 m, as judged from an only slightly pressure dependent generation time. (2) CNPT-3 is unquestionably barophilic at 2"0C, with doubling times of 9 hours at 580 bars and over 18 hours at 1 bar. (3) At 10"0C, reproduction is adversely affected at 1 bar to the extent that CNPT-3 becomes obligately barophilic at 10"0C. Yet reproduction is enhanced above 280 bars and occurs with a regeneration time ...
Aim: Rheumatoid arthritis is a limiting disease having, among its pathological features, the inflammation of synovial tissue with progressive and later destruction of the articulation. This leads to joint deformation and loss of its function, generating pain and reducing the mobility of the affected articulation. The aim was to evaluate "1"6"6Ho-Hydroxyapatite ("1"6"6 Ho-HA) as potential radiopharmaceutical for the symptomatic treatment of chronic and acute arthritis. Materials and Methods: Holmiun-166 was produced by irradiation of Ho_2O_3 at La Reina Research Reactor, Nuclear Chilean Energy Commission. Hydroxyapatite was in-house synthesized. Its labelling and quality controls follows the internationally accepted procedures. An antigen's arthritis was induced to eight New Zealand rabbits with the "1"6"6 Ho-HA radiochemical being administered thereafter in two dosage modalities (single and double). The compound therapeutic efficiency was ...
Ultraviolet (UV) upconversion (UC) luminescence in Yb3+/Er3+-codoped yttrium oxide (Y2O3) nanocrystals can be enhanced by orders of magnitude via tridoping further with Li+ ions under diode laser excitation of 970 nm. Sensitized three-photon UC radiations at 390 and 409 nm, corresponding to the 4G11/2?4I15/2 and 4H9/2?4I15/2 of Er3+ ions, respectively, present an enhancement time of about 33 times, which is larger than the 24 times enhancement for the UC green radiation. The UV UC radiation at 320 nm that corresponds to the 2P3/2?4I15/2 of Er3+ ions has also been greatly enhanced. Theoretical calculations interpret that all the observed enhancement times of UV UC radiations arise from the prolonged lifetimes of their intermediate states.
Solar ultraviolet radiation is damaging for living organisms due to its high energy pro each photon. The UV radiation is often separated into three regions according to the wavelength: UVC (200-280 nm), UVB (280-320 nm) and UVA (320-400 nm). The most hazardous part, UVC is absorbed completely in the upper atmosphere by molecular oxygen. UVB radiation is absorbed by atmospheric ozone partly, and it is reaching Earth`s surface, as UVA radiation. Besides atmospheric ozone, very important factors in determining the intensity of UVB radiation globally are the solar zenith angle and cloudiness. It may be calculated from global ozone changes that the clear-sky UVB doses may have enhanced by 10-15 % during spring and 5-10 % during summer at the latitudes of Finland, following the decrease of total ozone between 1979-90. The Finnish ozone and UV monitoring activities have become a part of international activities, especially the EU Environment and Climate Programme`s ...
This work estimates the power requirements for using photochemical processes driven by space nuclear power to counteract the Earth's ozone layer depletion. The total quantity of ozone (O_3) in the Earth's atmosphere is estimated to be about 4.7 x 10"3"7 molecules. The ozone production and destruction rates in the stratosphere are both on the order of 4.9 x 10"3"1 molecules/s, differing by a small fraction so that the net depletion rate is about 0.16 to 0.26% per year. The delivered optical power requirement for offsetting this depletion is estimated to be on the order of 3 GW. If the power were produced by satellite reactors at 800 km altitude (orbit decay time #approx# 300 years), some means of efficient power beaming would be needed to deliver the power to stratospheric levels (10--50 km). Ultraviolet radiation at 140--150 nm could have higher absorption rates in O_2 (leading to production of atomic oxygen, which can combine with O_2 to form O_3) than in ozone ...
The second list of objects in the Second Biurakan Spectral Sky Survey of the region centered on alpha 09h50m, delta +55 deg 00 arcmin is given. The list contains data on 110 objects and galaxies of a peculiar physical nature and 24 blue stars. The observations were made with the 40-52 arcsec Schmidt telescope of the Biurakan Astrophysical Observatory with a set of three objective prisms using Kodak IIIaJ and IIIaF emulsions sensitized in nitrogen. The area is found to contain 20 quasar candidates and four Seyfert galaxies, 27 blue stellar objects, 24 galaxies with an appreciable ultraviolet continuum, and 39 emission galaxies without appreciable ultraviolet radiation. The surface brightness of the quasars and Seyferts on the considered area down to the limiting magnitude 19.5 M is more than 1.5 per square degree with allowance for the already known quasars. The surface density of emission galaxies is about four per square degree. 7 references.
Marmesin was isolated from the medicinal plant, Afraegle paniculata. Its cytotoxicity and mutagenicity in Chinese hamster V79 cells when sensitized to near ultraviolet (NUV) and long wavelength ultraviolet light or black light (BL) were assayed. Marmesin was extremely cytotoxic in the dark. This cytotoxicity was photoenhanced in NUV and BL; the photoenhanced lethality being higher in NUV than in BL. The LD/sub 50/ of marmesin under NUV and BL photosensitization were 0.002 ..mu..M and (0.012 ..mu..M), respectively. In the absence of NUV and BL, marmesin's LD/sub 50/ was 0.013 ..mu..M.NUV and BL without marmesin were not significantly cytotoxic at the fluence rates of 0.29 W/m/sup 2/ and 4.2 W/m/sup 2/, respectively, for up to 20 min. In contrast to the observed high cytotoxicity of marmesin, its mutagenicity at the HGPRT locus (Asub(z)Gsup(r)) was weak. The implication of this result in the high incidence of skin cancer in Nigeria in ...
We present the general properties of the far-ultraviolet (FUV; 1370-1720A) continuum background over most of the sky, obtained with the Spectroscopy of Plasma Evolution from Astrophysical Radiation instrument (SPEAR, also known as FIMS), flown aboard the STSAT-1 satellite mission. We find that the diffuse FUV continuum intensity is well correlated with N_{HI}, 100 $\\mu$m, and H-alpha intensities but anti-correlated with soft X-ray. The strongest correlation is with the H-alpha emission, and the correlation of the diffuse background with the direct stellar flux is weaker than the correlation with other parameters. The continuum spectra are relatively flat. However, a weak softening of the FUV spectra toward some sight lines, mostly at high Galactic latitudes, is found not only in direct-stellar but also in diffuse background spectra. The diffuse background is relatively softer that the direct stellar spectrum. We also find that the diffuse FUV background averaged ...
Multilayer mirror coatings which reflect extreme ultraviolet (EUV) radiation are a key enabling technology for EUV lithography. Mo/Si multilayers with reflectances of 67.5% at 13.4 nm are now routinely achieved and reflectances of 70 2% at 11.4 nm were obtained with MO/Be multilayers. High reflectance is achieved with careful control of substrate quality, layer thicknesses, multilayer materials, interface quality, and surface termination. Reflectance and film stress were found to be stable relative to the requirements for application to EUV lithography. The run-to-run reproducibility of the reflectance peak position was characterized to be better than 0.2%, providing the required wavelength matching among the seven multilayer-coated mirrors used in the present lithography system design. Uniformity of coating was improved to better than 0.5% across 150 mm diameter substrates. These improvements in EUV multilayer mirror technology will enable us to meet the stringent ...
Ethidium bromide (EB) and ultraviolet light (UV) in combination are known to produce a synergistic induction of 'petite' mutants in yeast. Two other agents were combined with EB, 3-Carbethoxypsoralene (3 CPs) activated by 365 nm light or #gamma# rays. EB in combination with 3 CPs also resulted in an enhanced production of 'petite' mutants. After the photoaddition of 3 CPs in exponential phase cells, recovery of the 'petite' mutation during dark liquid holding was inhibited by the presence of EB producing an enhanced number of 'petite' mutants. The behavior of mitochondrial antibiotic resistance markers after individual and combined treatments with EB and 3 CPs indicates a random loss of markers after EB and a preferential loss of a certain region for the 3 CPs photoaddition. The combination of the two agents leads to an additivity of total drug marker losses rather than a synergistic loss. The combination of EB with #gamma# rays produced no enhancement in 'petite' ...
Nanocrystalline ZnO films were fabricated via a simple method involving the oxidation of Zn films at a remarkably low temperature of 380 C. X-ray diffraction study confirmed that the Zn films were completely oxidized even at the low temperature of 380 C and the ZnO films fabricated were of polycrystalline wurtzite structure. Room temperature optical pumping using a frequency-quintupled Q-switched Nd:YAG laser ({lambda}=213 nm) exhibited that sharp peaks at around 3.12 eV emerged above excitation powers of {proportional_to}7 MW/cm{sup 2}, demonstrating lasing in the ZnO films. These results represent that the process is a simple, promising approach for fabricating ZnO of sufficient optical performance for use as ultraviolet (UV) light emitters and an alternative UV laser source; both are key components in short-wavelength photonic devices. (orig.)
Proper assessment of the hypothesis which correlates polycyclic aromatic hydrocarbons (PAHs) with the unidentified infrared emission bands requires additional experimental laboratory data. In order to address this need, thermal infrared emission studies were performed on a subset of PAHs suggested to be of astrophysical importance. It was proposed that infrared emission from interstellar PAHs occurs following absorption of an ultraviolet photon. Since energy transfer to the ground electronic state can be rapid for a species in which intersystem crossing is negligible, the emission spectrum may be viewed as resulting from an equilibrium vibrational temperature (Leger and d'Hendecourt, 1987). This has been the basis for using infrared absorption spectra to calculate the corresponding emission spectra at various temperatures. These calculations were made using room temperature infrared absorption coefficients instead of those at the temperature of interest because of ...
We present ultraviolet spectra of Mira's companion star from the Space Telescope Imaging Spectrograph (STIS) instrument on board the Hubble Space Telescope (HST). The companion is generally assumed to be a white dwarf surrounded by an accretion disk fed by Mira's wind, which dominates the UV emission from the system. The STIS UV spectrum is dominated by numerous, narrow H2 lines fluoresced by H I Ly-alpha, which were not detected in any of the numerous observations of Mira B by the International Ultraviolet Explorer (IUE). The high temperature lines detected by IUE (e.g., C IV 1550) still exist in the STIS spectrum but with dramatically lower fluxes. The continuum fluxes in the STIS spectra are also much lower, being more than an order of magnitude lower than ever observed by IUE, and also an order of magnitude lower than fluxes observed in more recent HST Faint Object Camera objective prism spectra from 1995. Thus, the accretion rate onto Mira ...
Generally, neutron, ion and electron Irradiations cause a substantial amount of hardening and significantly alter the deformation behavior of metals and alloys at relatively low irradiation temperatures. A radiation hardening is caused by the formation of microstructural defects such as dislocation loops, voids and precipitates under irradiation. Therefore, it is important to have a better knowledge of the irradiation induced microstructural defects under irradiation condition. As a part of the National mid- and long-term atomic energy R and D program, we are dealing with the radiation hardening behavior in Fe-Cr binary alloy. Fe-Cr binary alloy is a base alloy of Ferritic/Martensitic steel(F/M steel) planning to use for the Gen IV nuclear system. In this work, we investigated the radiation hardening and microstructural defect evolution in ion irradiated Fe-Cr ...
Assessments of the hardening and embrittlement of pressure vessel steels and welds as a function of neutron dose use trend curves derived from surveillance programs and accelerated irradiation data. A temperature dependent factor is incorporated for assessing vessel locations operating at different temperatures. As hardening and embrittlement arise from the sum of matrix damage and copper impurity precipitation, the influence of irradiation temperature on each process needs to be established. For irradiations performed below #approx# 300 C recent data shows that the dose-dependent growth of copper precipitates ceases at a mean diameter of about 2 nm that also corresponds to peak hardening and embrittlement by copper. For doses beyond this peak copper dose the property-dependence on irradiation temperature can be identified with that of matrix damage alone. An analysis of several experiments on plate ...
This project has intended to develop alternative techniques to be used in food industry for food processing and utilization by safe irradiation methods. For improvement of rheology and processing in corn starch by irradiation, the production of modified starch with low viscosity as well as with excellent viscosity stability became feasible by the control of gamma irradiation dose levels and the amount of added inorganic peroxides to starch. Also, this project was developed the improvement methods of hygienic quality and long-term storage of dried red pepper by gamma irradiation. And, in Korean medicinal plants, 10 kGy gamma irradiation was effective for improving sanitary quality and increasing extraction yield of major components. For the sanitization of health and convenience foods, gamma irradiation was more effective than ozone treatment in decontamination ...
In this study, free electron laser (FEL) with selective wavelength was used to induce structure changes of biomolecules, which were characterized by FTIR spectroscopy. For understanding of the interactions between FEL and biomolecules as well as biological tissues, the biomolecules investigated are ATP, ADP, AMP, t-RNA, D-ribose and the complex of SmCl_3-D-ribose. Their FTIR spectra before and after irradiation of FEL show molecular structure variations of the samples after irradiation of FEL, especially the rearrangement of their hydrogen bond networks. Along with the various irradiation wavelengths, irradiation time and molecular structures, the changes after irradiation are different for these molecules. In the FTIR spectra after irradiation, the phenomenon that the bands split into several peaks indicates the existence of several structures, conformations ...
Various nylons including nylon 6, nylon 66, nylon 610 and nylon 12 in the forms of fiber and film were irradiated with the gamma-ray from Co-60 at the dose rate of 0.12 Mrad/hr in the atmosphere of oxygen at 7 kg/cm/sup 2/ and at the room temperature. The irradiation in vacuum on the same specimens was performed at 0.5 Mrad/hr. The tensile properties and the gel fraction of the irradiated nylon samples were measured, and the radiation resistance of the nylons against the irradiation at low dose rate was estimated. From the experimental results, it became clear that in the case of irradiation in vacuum, all the nylons were durable to the irradiation of 250 Mrad or more, and nylon 6 was more durable than nylon 12, and in the case of irradiation in pressurized oxygen, the radiation resistance of the nylons decreased to one-tenth as compared ...
Electronic circular dichroism (ECD) of the n-#pi# and #pi# -#pi# transitions of the amide groups in the ultraviolet has become an indispensable tool for qualitative characterization of proteins in solution. Since the existence of such a spectrum (that is, of natural optical activity) comes from the three dimensional interaction of the chromophores in the molecule, CD is exquisitely sensitive to molecular conformation. However, in proteins, the amide transitions available in the near UV are limited in number and are broads and overlapping. Interactions among them yield information about the polymeric backbone, but since such amide electronic excitation are relatively delocalized, the resulting
An electroweak model with running coupling constants described by an energy dependent entire function is utraviolet complete and avoids unitarity violations for energies above 1 TeV. The action contains no physical scalar fields and no Higgs particle and the physical electroweak model fields are local and satisfy microcausality. The $W$ and $Z$ masses are compatible with a symmetry breaking $SU(2)_L\\times U(1)_Y \\rightarrow U(1)_{\\rm em}$, which retains a massless photon. The vertex couplings possess an energy scale $\\Lambda_W > 1$ TeV predicting scattering amplitudes that can be tested at the LHC.
The Drell-Yan mechanism for the production of lepton pairs is one of the most basic processes for physics studies at hadron colliders. It is therefore important to have accurate theoretical predictions. In this work we compute the two-loop virtual mixed QCD x QED corrections to Drell-Yan production. We evaluate the Feynman diagrams by decomposing the amplitudes into a set of known master integrals and their coefficients, which allows us to derive an analytical result. We also perform a detailed study of the ultraviolet and infrared structure of the two-loop amplitude and the corresponding poles in epsilon.
This paper reports on the results of experiments into efficient higher-order anti-Stokes Raman conversion of tunable short-pulse XeCl laser radiation. The maximum output energy of the pumping laser, in which the radiation of a frequency-doubled dye laser is amplified by two XeCl laser amplifiers, is 55 mJ with a pulse duration of 1 ns FWHM. Using hydrogen gas as a Raman medium, a series of anti-Stokes lines up to the 12th order (121.5 nm) is generated in the vacuum ultraviolet (VUV) region. 16 references.
Tb3+-activated Sr3AlO4F phosphors were synthesized by a high-temperature solid-state reaction method. The investigation of photoluminescence and cathodoluminescence indicates that these phosphors can be effectively excited by ultraviolet light and low-voltage electron beam. The phosphors exhibit a tunable-green emission. The luminescence behaviors are explained by the site occupancy of Tb3+ ions in the host crystal and the cross-relaxation of 5D3 to 5D4 state.
Tb3+-activated Sr3AlO4F phosphors were synthesized by a high-temperature solid-state reaction method. The investigation of photoluminescence and cathodoluminescence indicates that these phosphors can be effectively excited by ultraviolet light and low-voltage electron beam. The phosphors exhibit a tunable-green emission. The luminescence behaviors are explained by the site occupancy of Tb3+ ions in the host crystal and the cross-relaxation of 5D3 to 5D4 state.
In situ optical absorption spectroscopy was used to study the generation of E' centres in amorphous SiO_2 occurring by photo-induced breaking of Si-H groups under 4.7eV pulsed laser radiation. The dependence from laser intensity of the defect generation rate is consistent with a two-photon mechanism for Si-H rupture, while the growth and the saturation of the defects are conditioned by their concurrent annealing due to reaction with mobile hydrogen arising from the same precursor. A rate equation is proposed to model the kinetics of the defects and tested on experimental data.
Pollen from four temperate-latitude taxa were treated with UV radiation in a portion of the UV-B (280-320 nm) waveband during in vitro germination. Inhibition of germination was noted in this pollen compared to samples treated identically except for the exclusion of the UV-B portion of the spectrum. Levels similar to maximum solar UV-B found in temperate-latitude areas failed to inhibit pollen germination significantly, while levels similar to maximum solar UV-B found in equatorial alpine locations caused partial inhibition of germination in three of the four taxa examined.
We studied the optimum plasma conditions that are required for efficient high-order harmonic generation in platinum plume. Harmonics up to the 49th order (?=16.32 nm) are analyzed under various conditions of laser-plasma interaction. Time-resolved ultraviolet spectra of platinum plasma at both optimum and nonoptimum conditions of harmonic generation are presented. We calculated the ionization states of the plasma, free electron density, and singly charged ion density at different prepulse intensities and compared them with experimental results.
Laser gain of the NIJI-IV compact storage-ring-based Free Electron Laser (FEL) system at AIST reached #approx#9% at 200 nm for an average beam current of 16.3 mA. In addition to such a drastic gain enhancement, improvement of the laser-cavity performance has led to successful FEL lasing in the vacuum ultraviolet below 200 nm even in a compact system. Temporal and spectral characteristics of the NIJI-IV FEL were examined around 200 nm. FEL performance will be briefly discussed from the application point of view.
We explore autofluorescence endomicroscopy as a potential tool for real-time visualization of epithelial tissue microstructure and organization in a clinical setting. The design parameters are explored using two experimental systems--an Olympus Medical Systems Corp. stand-alone clinical prototype probe, and a custom built bench-top rigid fiber conduit prototype. Both systems entail ultraviolet excitation at 266 nm and/or 325 nm using compact laser sources. Preliminary results using ex vivo animal and human tissue specimens suggest that this technology can be translated toward in vivo application to address the need for real-time histology.
As part of a project to complete a comprehensive catalogue of astrophysically relevant emission lines in support of new-generation X-ray observatories using the Lawrence Livermore electron beam ion traps EBIT-I and EBIT-II, we studied emission lines of argon and sulfur in the soft X-ray and extreme ultraviolet region. Here we present observations of Ar IX through Ar XVI and S VII through S XIV between 20 and 75 {angstrom} to illustrate our work.
Enzyme-linked Immunosorbent assay systems for the identification of irradiated egg, pork and chicken was developed. Eggs were irradiated in their shells to 0.5{approx}7kGy. Pork was irradiated to 0.5{approx}3kGy and chicken irradiated to 0.5kGy{approx}5kGy. The most sensitive proteins to irradiation were screened by SDS-PAGE and purified. Ovalbumin from egg, salt soluble protein(p) from pork, and salt soluble protein(c) from chicken showed the most sensitivity to irradiation. To investigate for a practical use in identifying of irradiated egg, pork and chicken, competitive ELISA was performed. The binding activity of ovalbumin to anti-ovalbumin IgG was reduced in a dose-dependent manner by irradiating up to 7kGy, and considerably lowered after irradiating at 7kGy. The concentration of 50% inhibition ...
We derive stellar masses, ages, and star formation histories (SFHs) of massive early-type galaxies in the z = 1.237 RDCS1252.9-2927 cluster and compare them with those measured in a similarly mass-selected sample of field contemporaries drawn from the Great Observatories Origin Deep Survey South Field. Robust estimates of these parameters are obtained by comparing a large grid of composite stellar population models with 8-9 band photometry in the rest-frame near-ultraviolet, optical, and IR, thus sampling the entire relevant domain of emission of the different stellar populations. Additionally, we present new, deep U-band photometry of both fields, giving access to the critical far-ultraviolet rest frame, in order to empirically constrain the dependence of the most recent star formation processes on the environment. We also analyze the morphological properties of both samples to examine the dependence of their scaling relations on their mass ...
To get a considerable reduction of the radiotoxicity due to americium, a thermal neutron fluence of 2.10{sup 22} cm{sup -2} or a fast neutron fluence of 2.10{sup 24} cm{sup -2} is required. Irradiation in a thermal neutron flux leads to lower masses of {sup 234}U and precursors and of {sup 237}Np and precursors, but to higher curium masses and much higher neutron emission rates than irradiation in a fast neutron flux. Therefore, irradiation in a fast neutron flux has preference when multiple recycling is adopted. When once-through burning is applied, irradiation in a thermal neutron flux can be applied. Then irradiation in a heavy water reactor (HWR) has preference above irradiation in a PWR or in a high temperature gas-cooled reactor (HTGR). (authors) 4 refs.
To get a considerable reduction of the radiotoxicity due to americium, a thermal neutron fluence of 2.10{sup 22} cm{sup -2} or a fast neutron fluence of 2.10{sup 24} cm{sup -2} is required. Irradiation in a thermal neutron flux leads to lower masses of {sup 234}U and precursors and of {sup 237}Np and precursors, but to higher curium masses and much higher neutron emission rates than irradiation in a fast neutron flux. Therefore, irradiation in a fast neutron flux has preference when multiple recycling is adopted. When once-through burning is applied, irradiation in a thermal neutron flux can be applied. Then irradiation in a HWR has preference above irradiation in a PWR or in a HTGR. (orig.).
The project was designed to solve the infra structural problem required for commercialization of food irradiation. In improvement of physical properties of corn starch, gamma irradiation was effective for increasing glucose productivity and for substituting traditional modified starches (acid modified starch, oxidized starch). In immobilization of microorganisms, the mass production method of natural red pigment was developed by using immobilized mold pellets. In Korean medicinal plants, 10 kGy gamma irradiation was effective for improving sanitary quality and increasing extraction yield. In evaluation of wholesomeness, gamma irradiated red ginseng could be safe on the genotoxic point of view. And also, six items of irradiated foods approved for human consumption from Korea ministry of health and welfare in May 19, 1995. 30 figs, 20 tabs, 54 refs. (Author).
The results of this study are in agreement with the precepts established in studies published previously on beef, chicken, ham, and pork. The radiolysis compounds from bacon, chicken, ham, and pork are comparable in identity and amounts to those found in irradiated beef for comparable compositions and irradiation parameters (temperature, dose, etc.). The results of this study support the conclusions drawn in the CORC report of 'commonality in chemistry, predictability of products, and extrapolation of results.' Consequently, the same conclusions can be drawn concerning the wholesomeness of irradiated bacon, chicken, ham, and pork as for other irradiated meat products of similar composition and irradiation parameters as reported in the FASEB report and its supplements (I and II) on irradiated beef.
Thermoluminescence of inorganic dust extract from herbs and spices has been demonstrated to be a useful method to discriminate irradiated food products as well as to estimate the total dose exposure. The time evolution of infrared stimulated luminescence has been systematically investigated in potassium feldspar and albite minerals subjected to different doses of gamma irradiation (ranging from 0 to 8 kGy). Experimental results reveal a 300-600 nm signal which is greatly intensified for irradiated samples, following the same irradiation dose dependence observed in thermoluminescence. The luminescence intensity disappears after few seconds of illumination, following a time evolution which is proportional to (1 + Bt){sup -P}. The influence of both B and P factors upon the irradiation dose has been systematically analysed. (author)
Thermoluminescence of inorganic dust extract from herbs and spices has been demonstrated to be a useful method to discriminate irradiated food products as well as to estimate the total dose exposure. The time evolution of infrared stimulated luminescence has been systematically investigated in potassium feldspar and albite minerals subjected to different doses of gamma irradiation (ranging from 0 to 8 kGy). Experimental results reveal a 300-600 nm signal which is greatly intensified for irradiated samples, following the same irradiation dose dependence observed in thermoluminescence. The luminescence intensity disappears after few seconds of illumination, following a time evolution which is proportional to (1 + Bt)"-"P. The influence of both B and P factors upon the irradiation dose has been systematically analysed. (author)
This discussion paper has two goals: first, to raise public awareness of food irradiation, an emerging technology in which Canada has the potential to build a new industry, mainly oriented to promising overseas markets; and second, to help build consensus among government and private sector decision makers about what has to be done to realize the domestic and export potential. The following pages discuss the potential of food irradiation; indicate how food is irradiated; outline the uses of food irradiation; examine questions of the safety of the equipment and both the safety and nutritional value of irradiated food; look at international commercial developments; assess the current and emerging domestic scene; and finally, draw some conclusions and offer suggestions for action.
Pd/n-Si and Pd/n-GaAs devices have been irradiated from high energy ({approx}100 MeV) heavy ions of Au{sup 7+} (gold) and Si{sup 7+} (silicon) to study the irradiation effects in these junction devices on semiconductor substrates. The devices have been characterized from I-V and C-V studies for electronic flow characterization. It has been found that the devices become high resistive on the irradiation and the substrates change the conductivity type from n- to p- on the irradiation of fluence of {approx}10{sup 12}-10{sup 13} ions/cm{sup 2}. The change in conductivity type has been understood as a result of creation of deep acceptors on the irradiation.
Ferrite of system, namely Ni_1_-_xZn_xFe_2O_4 with x = (0.0, 0.2, 0.4, 0.6, 0.8, 1.0), have been prepared by solid state reaction to investigate the effect of gamma rays irradiations using Co"6"0 source on the cation distribution, structural and magnetic properties. The unirradiated and irradiated samples were then subjected to characterization techniques such as X-ray diffraction, magnetization and AC susceptibility. The results of these characterizations are found to be different for irradiated from that of the pristine sample. The modifications in respect of irradiated samples are explained in terms of the ion-induced disorder. The important result of #gamma#-irradiation on the cation distribution, structural and magnetic properties is the change of ratio Fe"2"+/Fe"3"+. Possible reasons on the results are proposed.
Young rats were given a single irradiation dose (0.5, 2, 5 or 8 Gy) to the left knee-joint. The right unexposed knee-joint served as control. The animals were decapitated 1.5, 3, 7, 14 or 30 days after the irradiation. Longitudinal bone growth in the tibial epiphysis was established using tetracycline as an intravital marker. During the first 1.5 days after irradiation with 5 and 8 Gy, the growth was slightly inhibited (6-7%). Maximum growth retardation (20%) was found 7 to 14 days after irradiation with 5 and 8 Gy. No consistent effect occurred after 0.5 and 2 Gy. Between 14 to 30 days following irradiation growth was normalized.
The ability of a local strain of grape phylloxera to develop and reproduce on irradiated in vitro cultured rootstocks (Ru140, R99 and 3309C and one local variety 'Helwani' was determined. The results showed that there was great variation in developmental time and reproduction of phylloxera between irradiated and unirradiated in vitro cultured plants. Survival, number of eggs and mean developmental time were greatly reduced when phylloxera was reared on irradiated rootstocks. Based on the examined biological parameters of phylloxera, all tested rootstocks would be more resistant toward such destructive insect when they were irradiated. Thus, phylloxera resistance was enhanced when in vitro cultured plants were treated with low doses of gamma irradiation. (author)
In this study, the degrees of destruction of hemoglobin irradiated in atmospheres of air and argon were compared. Hemoglobin preparations were irradiated in the forms: oxyhemoglobin (HbO_2) deoxyhemoglobin (Hb"2"+) and methemoglobin (MetHb) applying doses of 0.5 to 5 Mrad. The degree of hemoglobin destruction was estimate on the basis of changes in the values of the absorption coefficient at the Soret band, the absorption ratio A_5_0_5/A_5_6_3 determined after conversion of irradiated preparations into MetHb, absorption coefficinets for pyridine hemochromogen obtained from irradiated preparations, and changes in parameters characterizing the hemoglobin oxygenation reaction (log p/sub 1/2/O_2 and the Hill n coefficient). The calculated oxygen enhancement ratios S were generally higher than 1 for the parameters estimated. This indicates that the presence of oxygen during irradiation ...
The language used by chronic benign pain patients to characterize their pain complaint was analyzed to determine the best predictor of psychiatric disturbance. Using the 78 adjectives provided by the McGill Pain Questionnaire, the number of affective descriptors used was the best predictor of psychiatric disturbance. Addition of sensory descriptors either to augment the total number of descriptors used (magnitude) or as a pattern of sensory greater than affective or sensory less than affective failed to increase predictive strength. PMID:6877847
As part of a combined study of the responses of the mouse adrenal gland and kidney to X-irradiation, the weight of adrenal glands, the relative volumes of the cortex and medulla and the aldosterone output were measured at predetermined times after irradiation of the left organs only.
By using this doping method, silicon semiconductors with extremely uniform dopant distributions can be produced, and this is the dominant advantage of NTD compared with a conventional chemical doping. Good uniformity of a dopant concentration is usually required for high power applications such as thyristor (SCR), IGBT, IGCT and GTO and for special sensors. Achieving an accurate neutron fluence corresponding to a target resistivity as well as a uniform irradiation is the prime target of a neutron irradiation for NTD. Generally, in order to reach an accurate neutron fluence, a real time neutron flux is monitored by a neutron detector such as a Self-powered Neutron Detector(SPND). And, after an irradiation, the total irradiation fluence is confirmed by measuring the absolute activity of a neutron activation sample that has been irradiated with a silicon ingot, and thus the SPND can be ...
The formation of porous structures of nanometre size (nanoporous structures) on germanium (Ge) surfaces by focused ion beam (FIB) irradiations was investigated using various FIB conditions such as ion species, irradiation energies, total fluences, fluence rates, and incident angles. FIB-irradiated regions were observed using a scanning electron microscope and an atomic force microscope. It is found that, using a focused Ga ion beam (Ga FIB) at an energy of 100 keV, the irradiated Ge surface swelled up to ion fluence of 2 x 10"1"7 cm"-"2 with nanoporous structures and then was etched for larger fluences. The shape of swollen nanoporous structures depended on the fluence rate and the incident angle of the Ga FIB. However, such porous structures were observed neither for low-energy (15-30 keV) FIB irradiations using Si and Au ions nor for high-energy (200 keV), heavy ion (Au) ...
Type 316 stainless steel is the primary candidate austenitic structural material for fusion first wall constructions. Here, type 316L(N) stainless steel plate material has been irradiated up to 10 dpa at temperatures of 80, 225, 325, and 425 C in the High Flux Reactor (HFR) of Petten. Tensile tests have been performed in the temperature range from RT to 575 C at a conventional strain rate of 5 x 10"-"4 s"-"1. The results of the tensile tests are analyzed in terms of irradiation hardening and loss of ductility due to irradiation. Tensile properties saturate in the early stage (within 0.65 dpa) at the lowest applied irradiation temperature. It is indicated that the most severe degradation of tensile ductility occurs in the temperature range of 275 to 350 C. Comparison with literature data revealed a large scatter in irradiation hardening at irradiation ...
In view of poor local control rates obtained with standard treatment, intraoperative radiation (IORT) using electrons was combined with external beam irradiation and surgical resection, with or without...Full Text Available
The use of cathode ray irradiated arterial allografts on the reconstruction of small peripheral arteries is described. The fate of irradiated arterial allografts implanted subcutaneously in rats was compared histologically with that of allografts which were fresh, frozen or stored in 70% alcohol. Follow-up studies were made of 10 dogs in which irradiated arterial allografts had been implanted in the femoral artery to be evaluated; long term patency by arteriography, gross and histologic changes of the implanted allografts, and the luminal surface of the implanted allografts by scanning electron microscopic studies. For the purpose of antigenic studies, extracts of canine arteries which had been irradiated, frozen or stored in 70% alcohol, were prepared and tested by the following immunological methods: precipitation, Ouchterlony gel diffusion, and passive cutaneous anaphylaxis. From the results obtained ...
This experiment was done to determine the effects of irradiation on the physical properties of three kinds of laminated packaging materials, i.e. polypropylene-polypropylene, polypropylene-polyethylene, polyester-polyethylene. Observations were made on pinhole production, leakage, oil resistance, resistance against insect penetration, colour, odour tensile strength, elongation at break, seal strength and tear resistance. The samples were irradiated with doses of 0, 5 and 10 kGy, then stored at room temperature and examined after 0, 3, 6 and 12 months of storage. The results showed that irradiation doses up to 10 kGy, as well as storage up to 12 months, did not create pinholes, or leakage in pouches prepared from laminated films. The resistance of the films to oil and insect penetration, the colour, and the odour were also unchanged. Both irradiation and storage treatments had a significant effect on ...
The effects of gamma and e-beam irradiation on mechanical and structural properties of nylon 66 (Ny 66), nylon 6 (Ny 6) and poly(ethylene terephthalate) (PET) fabrics used in tyres were investigated. The untreated (greige), treated cords and calendered fabrics were irradiated at different doses. It is found that the effects of high energy irradiation on greige, treated cords and calendered fabrics are similar. No protective effect of compounds used in calendering was observed against radiation-induced oxidative degradation. The deterioration effect of gamma irradiation on mechanical properties is much higher than that of e-beam irradiation for all types of samples. Limiting viscosity numbers of both gamma and e-beam irradiated nylon 6 and nylon 66 cords were found to decrease with increasing dose. It is concluded that PET calendered fabric has higher resistance ...
Tensile properties of reduced-activation 10Cr-30Mn austenitic steels with carbon levels from 0.003 to 0.55% were investigated over the temperature range from room temperature to 873 K after neutron irradiation in the Japan Materials Testing Reactor at 573 K to 8.5x10"2"2 n/m"2. Irradiation-induced increase in yield stress increased significantly with carbon concentration up to about 0.1% and it was constant above 0.1% carbon. A high density of dislocation loops with small (below 10 nm) and large (20-30 nm) sizes formed during irradiation. The high density, small loops caused a large irradiation hardening, while the large loops contributed only slightly to irradiation hardening. It was considered that carbon atoms formed the small loops together with irradiation defects. The deformation channeling was observed in the irradiated high carbon ...
The dielectrical properties of organosilicon sealants have been studied in the wide range of temperatures in the low and radio frequencies range. The effect of thermal treatment and #gamma#-irradiation on these properties is discussed.
A nonmammalian test system for germ-cell mutagenesis has been developed by using the Japanese medaka fish. We describe a system for detecting DNA alterations in F1 progeny descended from the gamma-irradiated...Full Text Available
Six children who received craniospinal irradiation for medulloblastoma when they were under 10 years of age developed learning disabilities. Four exhibited associated temporal lobe calcification on...Full Text Available
Initial results obtained with a Monte Carlo computer program designed to link initial physical events in irradiated liquid water with subsequent chemical and biological events are presented. 10 refs., 4 figs., 3 tabs.
Radioisotope facilities were operated to support research, development and production of radioisotopes. Irradiation facilities were operated to offer irradiation service to the clients. Even though intensive periodical checks and some essential maintenance had been carried out the results of RI facility maintenance seemed to be not much satisfactory due mainly to the shortage of skilled manpower and maintenance expenses. High intensity {gamma} irradiator was normally operated 426 times for overall 3,440 hrs, and the low intensity {gamma} irradiator was operated 157 times for overall 11,092 hrs, respectively. (author)
A nonlinear relationship between the time of accelerated aging of Lupine seeds and the indices of its survival as well as the single-strand DNA amount in cells from these seeds is established. The character of this relationship is essentially altered in chronically irradiated lupine seeds from the Chernobyl NPP exclusion zone and seems more complicated. The possible role of repair systems in these effects is discussed. The fact that chronic irradiation in low doses can modify the course of senescence in lupine seeds reflects its high biological efficiency comparing with acute irradiation.
In the Institute of Nuclear Chemistry and Technology research on microbiological decontamination of medicinal herbs by irradiation has been carried out since 1996. It was shown that using ionizing radiation (a dose of 10 kGy) can obtain satisfactory results of microbiological decontamination of these products. The content of essential biologically active substances such as essential oils, flavonoids, glycosides, anthocyans, antra-compounds, poliphenoloacids, triterpene saponins, oleanosides and plants mucus did not change significantly after irradiation. Pharmacological activity of medicinal herbs has been found satisfactory after microbiological decontamination by irradiation.
In view of the interest in the use of gamma irradiation to extend the storage life of pre-packaged foods a report is made on the effects of gamma radiation on the migration of Irganox 1076 and Irganox 1010, antioxidants present in food packaging plastics, into synthetic triglyceride fatty-food simulant HB307 and iso-octane. The extent of migration was assayed by h.p.l.c. techniques. Migration into HB307 and iso-octane decreased steadily as irradiation progressed suggesting that gamma irradiation of packaging materials helps to prevent the contamination of food by antioxidants in the packaging. (U.K.).
Radiotherapeutic results of the Ewing sarcoma of the long tubular bones in 140 pediatric patients aged 3-16 are analyzed with the respect to different methods of irradiation. Three-field irradiation, the fields being located at 120 deg to one another with daily irradiation of all three fields at a focal dose of 2 Gy, was found superior in treatment of primary neoplasm. It is stressed that the disease termination mainly depends on the efficiency of primary neoplasm treatment, as the neoplasm reccurence generally is followed by metastases. Radiation load is calculated for maximal irradiation area of soft tissues in children.
The damage induced by low-temperature proton irradiation in amorphous Pd/sub 80/Si/sub 20/ prepared by ion implantation is studied via electrical resistivity measurements. Our experimental results concerning the initial damage rate and the resistivity saturation are compared to the results obtained for electron and high energy /sup 16/O irradiation of amorphous Pd/sub 80/Si/sub 20/ quenched from the melt. The resistivity curve is analyzed in terms of irradiation-induced point defects.
The effects of irradiation on microbiological controlling, nutrient and sensory qualities of packaged tofu (bean curd) stored at commercial condition. Results showed that D10 values of Listeria innocua and Samonella enteritidis inoculated in packaged tofu were 0.225 and 0.240kGy, respectively. Irradiation dose lower than 2.0kGy had no significant effects on content of crude protein and amino acid (p>0.05). ?-irradiation could decrease microbial in packaged tofu and 2.0kGy should be applied to ensure the hygienic quality of the products. (authors)
The interest of irradiation by carbon ions is in the fact that the carbon ions leave all their energy to a determined depth. ( phenomenon known under the name of Bragg peak)This high diffusion in tissue gives an RBE particularly high. The indications of this therapy are chordomas, and chondrosarcomas of the skull base, some cyst adenoid carcinomas, pulmonary cancer, sarcomas, hepato carcinomas, melanomas. In the light of results in term of efficiency, the place of irradiation by carbon ions should widen. (N.C.)
Structural changes of a Ni-P amorphous alloy under focused-ion-beam (FIB) irradiation have been examined using transmission electron microscopy. On the irradiated plane, the formation of crystallographically orientated nanosized crystals (NCs), with the particle size of approximately 10 nm, was observed. A series of electron diffraction analyses have revealed that NCs have a face-centered-cubic (fcc) structure and the following orientation relationships between the NCs and the FIB direction were found. These are, irradiated plane//(111)_f_c_c and FIB direction//_f_c_c.
We have investigated the formation and coarsening of Ga droplets on focused-ion-beam (FIB) irradiated GaAs surfaces. To separately examine formation and coarsening, Ga droplets were fabricated by Ga"+ FIB irradiation of GaAs substrates with and without pre-patterned holes. We determined the droplet growth rate and size distribution as a function of FIB energy following irradiation. The data suggest a droplet formation mechanism that involves Ga precipitation from a Ga-rich layer, followed by droplet coarsening via a combination of diffusion and Ostwald ripening or coalescence via droplet migration (dynamic coalescence).
Transmissions of sperm by unirradiated and irradiated cotton bollworm, Helicoverpa armigera, were studied by live dissection of females immediately after the initiation of mating. In cotton bollworm the sperm transfer was rather a complex process. In fact unirradiated males failed to transfer sperm in about 19% of their matings. When irradiated with 250 Gy and 400 Gy, aberrations of sperm transmission were about 21% and 50% respectively. The failure of spermatophore 'cap' location was an important reason of sperm transmission aberrations. When females mated to high-dose-irradiated males, their oviposition response appeared abnormal
A computer-assisted rotation and stationary conformation radiotherapy system with overrunning multileaf collimators has been developed. This system can produce any shape of target volume, including a number of target areas outside the axis of the rotation, regardless of the location of the axis at 360"0 rotation irradiation. In addition, by changing the dose rate and deleting a partial region within a field, multiple stationary irradiation can produce more homogeneous target volumes - thus avoiding excessive irradiation to critical organs - than the rotation technique. (orig.).
{sup 60}Co is produced as an activation product and is present in the low-level aqueous radioactive waste released from the La Hague plant. At present, the concentration in the sea (non filtered at 0.45 {mu}m) at the Goury site are close to or even below, the detection limit: 0.2 mBq.l{sup -1}. The {sup 60}Co speciation depends on the type of effluent considered: in the effluent A ('active'), the cobalt is in the form of a stable trivalent complex; in the effluent V (to be checked), the cobalt is in majority (50% of the activity release) in the form of particles (>0.45 {mu}m), and then in the form of two soluble species: ionic divalent (Co{sup 2+}) and some stable complexes. The evolution of the reprocessing techniques used does not affect the speciation. So, since the nuclear reprocessing plant started at the La Hague plant in 1966, the chemical species discharged in the sea shows time variation related to the evolution of the type of ...
The paper reports the recovery of zinc and cadmium following 6.1 MeV alpha particle irradiation at 4.2 K as studied by means of electrical reistivity measurements. Specimens of 10 #mu#m thick have been used in order to obtain a homogeneous defect distribution over the whole thickness of the specimen. The pre-irradiation resistivity ratios were 700 and 750 for cadmium and zinc, respectively. (Auth.).
The necessity of the electron beam machine characterization via dose measurement is discussed. It includes a measurement of comprehensive dose distribution (at known X and Z axis) for verification of the machine performance. The acquired data were then used to develop the irradiation parameters such as energy, current, distance, conveyor speed, exposure rate and depth inside product to be irradiated. These parameters will be used as a guide for the routine irradiations. (Author)
The structural variations of amorphous metals, such as Pd/sub 80/Si/sub 20/, with irradiation of helium ion, neutron, and gamma ray have been mainly pursued by the method of X-ray diffraction and thermal analysis. It should be noticed that the amorphous metals show a radiation resistance, that is, no remarkable structural changes under helium ion, neutron, and gamma ray irradiation.
Production of lead-203 by proton irradiation of bismuth metal has been investigated as a replacement method for commercially available lead-203. Targets of bismuth metal (0.1 cm thick) were irradiated for periods of 1-3 hours with 90 MeV protons. After processing of the target, the estimated yield of lead-2-3 was 30 millicuries/microamp.
Wood/polymer composites (WPC) have been prepared from pinewood with different compounds using gamma irradiation: butyl acrylate, butyl methacrylate, styrene, acrylamide, acrylonitrile, and unsaturated polyester styrene resin. The polymer loading was determined with respect to the compound concentration and the irradiation dose. The polymer loading increases generally with increase in the monomer or polymer concentration. Tensile and compression strength have been improved in the four cases, but no improvement was observed using unsaturated polyester styrene resin or acrylamide.
Post-irradiation annealing was used to help identify the role of radiation-induced segregation (RIS) in irradiation-assisted stress corrosion cracking (IASCC) by preferentially removing dislocation loop damage from proton-irradiated austenitic stainless steels while leaving the RIS of major and minor alloying elements largely unchanged. The goal of this study is to better understand the underlying mechanisms of IASCC. Simulations of post-irradiation annealing of RIS and dislocation loop microstructure predicted that dislocation loops would be removed preferentially over RIS due to both thermodynamic and kinetic considerations. To verify the simulation predictions, a series of post-irradiation annealing experiments were performed. Both a high purity 304L (HP-304L) and a commercial purity 304 (CP-304) stainless steel alloy were irradiated with 3.2 MeV protons at ...
The study by impedance and photoelectrochemical measurements of passive films formed on an AISI 304 type stainless steel shows that important parameters of the electronic structure of these films are modified under ..cap alpha.. irradiation, namely: width of the space charge region, donors concentration and diffusion length for minority carriers. The consequences of ..cap alpha.. irradiation on localized corrosion processes are discussed.
The study by impedance and photoelectrochemical measurements of passive films formed on an AISI 304 type stainless steel shows that important parameters of the electronic structure of these films are modified under #alpha# irradiation, namely: width of the space charge region, donors concentration and diffusion length for minority carriers. The consequences of #alpha# irradiation on localized corrosion processes are discussed.
This report introduces present status on food irradiation at home and abroad in detail. It also introduces the scientific research and application in reducing diseases caused by food borne pathogens, quarantine control of import and export products, grain store and killing insects in traditional Chinese medicine. The report also analyzes the problems in developing food irradiation in China and gives some suggestions
Effects of gamma irradiation on the physiological effectiveness of Korean medicinal herbs were investigated. The physiological effectiveness including antioxidant and anticomplement function, nitrite scavenging and electron donating ability of Korean medicinal herbs by gamma irradiation at 10 kGy did not differ from that of the nonirradiated control.
Effects of gamma irradiation on hygienic quality and extraction yields in twenty-one kinds of Korean medicinal herbs were investigated. Gamma irradiation at 5-10 kGy inactivated contaminating microorganisms. The total extraction yield in fifteen kinds of the investigated medicinal herbs increased by 5-25% by a dose of 10 kGy. (author)
This paper describes the research and development activities in three areas of radiation processing, namely: food irradiation, medical product sterilization and wood plastic combination. Plans and efforts exerted to acquire a larger gamma source to augment our present 5,000 curie source are discussed. Cost estimates for a radiation facility are presented on the basis of the market potential of food irradiation and medical product sterilization. Existing local industries that can benefit from the adaptation of irradiation technology in their processing requirements are described.
Heavy-ion irradiation technique has been developed for the evaluation of single-event effects on semiconductor devices. For the uniform irradiation of high energy heavy ions to device samples, we have designed and installed a magnetic beam-scanning system in a JAERI cyclotron beam course. It was found that scanned area was approximately 4 x 2 centimeters and that the deviation of ion fluence from the average value was less than 7%. (author)
The decree refers to conditions of irradiation of food and its components for radappertization and radurization using gamma radiation from cobalt 60 or cesium 137, X radiation or electron beam up to maximum total medium absorbed dose 10 kGy.
The effect of addition of rosemary and oregano extracts on the sensory quality of irradiated beef burger was investigated. Batches of beef burgers were prepared with 400 ppm of rosemary or oregano extract and a group prepared with 200 ppm of synthetic butyl-hydroxytoluene (BHT)/butyl-hydroxy-anisol (BHA) was used as a control. Half of each formulation was irradiated at the maximum dose allowed for frozen meat (7 kGy). Samples were kept under frozen conditions (-20 deg. C) during the whole storage period, including during irradiation. Two analyses were performed after 20 and 90 days to verify the influence of the addition of the different types of antioxidants and the effect of irradiation and storage time on the acceptance of the product. Thirty-three and thirty-four untrained panelists were invited to participate in the first and second test, respectively. A structured hedonic scale ranging from 1 to 9 ...
The availability of rice, gamma -irradiated up to 4.6 x 10/sup 4/ and 3.5 x 10/sup 5/r for koji was studied. The enzyme activities of koji of the steamed samples were stronger than the unirradiated rice in amylase and protease. The sensory test on the once-steamed irradiated rice was almost the same as the twice-steamed unirradiated rice. (OID)
Two experiments used the McGill Pain Questionnaire (MPQ) to examine the affective dimension of pain in patients whose pain was secondary to malignancy. In experiment I, segregating groups of cancer patients on the basis of extreme scores (high versus low) on the MPQ failed to produce segregation on independent measures of affect and infirmity. This outcome contrasts with earlier work with chronic benign pain patients. Experiment II compared cancer pain patients matched with benign pain patients on intensity of pain report on the affective dimension of the MPQ. Cancer pain patients reported a reliably higher affective loading to their pain. These data suggest that cancer pain patients employ different criteria than benign pain patients in selecting affective pain descriptors. Possible explanations for this difference are discussed. PMID:7070825
Full text of publication follows: Radiation hardening and embrittlement due to high-energy neutron radiation around 623 K are the important issues on reduced-activation ferritic/martensitic (RAF/M) steels. It is expected that the improvement of radiation hardening might be one of effective ways to control the mechanical properties of RAF/M after irradiation. It has been reported that the weld joint has less hardening than the base metal from the tensile test results of TIG weldments irradiated in HFIR. This report indicated that radiation hardening can be reduced by the optimization of heat treatment condition for F82H. The purposes of this study are to establish the condition of heat treatment for minimum of radiation hardening in F82H steel using Neutron/Ion-irradiation and to examine a correlation between tensile property and micro-hardness before/after irradiation. The materials used in this study ...
New sets of cross sections for the production of krypton isotopes from targets of Rb, Sr, Y, and Zr were constructed primarily on the bases of experimental excitation functions for Kr production from Y. These cross sections were used to calculate galactic-cosmic-ray and solar-proton production rates for Kr isotopes in the moon. Spallation Kr data obtained from ilmenite separates of rocks 10017 and 10047 are reported. Production rates and isotopic ratios for cosmogenic Kr observed in ten well-documented lunar samples and in ilmenite separates and bulk samples from several lunar rocks with long but unknown irradiation histories were compared with predicted rates and ratios. The agreements were generally quite good. Erosion of rock surfaces affected rates or ratios for only near-surface samples, where solar-proton production is important. There were considerable spreads in predicted-to-observed production rates of /sup 83/Kr, due at least in part ...
An add-on multileaf collimator for electrons (eMLC) has been developed that provides computer-controlled beam collimation and isocentric dose delivery. The design parameters result from the design study by Gauer et al (2006 Phys. Med. Biol. 51 5987-6003) and were configured such that a compact and light-weight eMLC with motorized leaves can be industrially manufactured and stably mounted on a conventional linear accelerator. In the present study, the efficiency of an initial computer-controlled prototype was examined according to the design goals and the performance of energy- and intensity-modulated treatment techniques. This study concentrates on the attachment and gantry stability as well as the dosimetric characteristics of central-axis and off-axis dose, field size dependence, collimator scatter, field abutment, radiation leakage and the setting of the accelerator jaws. To provide isocentric irradiation, the eMLC can be placed either 16 or 28 cm above the ...
This paper discusses the economics of legumes irradiation such as Chickpea,Lupin,Kidny Bean and broad and the effect of various parameters on unit processing costs. It provides a model for calculating specific unit processing costs by correlating known capital costs with annual operation cost an annual throughputs. We analysed the cost-benefit of the proposed grain irradiation facility. We took into account the cost of the capital investment, operation and other additional parameters and then estimated the unit processing cost. The investment criteria utilized for commercial evaluation were internal rate of return (I.I.R), pay back period (P.B.P), and average rate of return (A.R.R). The irradiation cost and the additional income are also discussed. The results of this analysis showed that the installation of an irradiation unit for legumes processing in Egypt would be economically feasible.
Microbiological comparison between irradiated and non-irradiated foodstuff has been studied for a long time as a way to detect whether a foodstuff has been irradiated or not. Generally, the proposed methods are based on the fact that ionization select species of bacteria which are recognized to be radioresistant. So reduction or elimination of known radiation sensitive microbes from the normal endogenous microflora could give an indication that the foodstuff has been irradiated, predominance of known radioresistant bacteria should be another indication. In the present work, we try to develop a test based on the radiosensitivity of the bacteria independently of their place. These first experiments show that the determination of radiosensitivity of strains isolated from a product or even of global radioresistance of mesophilic microflora could indicate if this product has been previously submitted to ...
The influence of electron-beam irradiation on mechanical properties of commercial multilayer flexible packaging materials based on coextruded and laminated polypropylene (PP), low-density polyethylene (LDPE), ethylene vinyl alcohol copolymer (EVOH) and poly(ethylene terephthalate) (PET), irradiated with doses up to 120 kGy, was studied. The tensile strength and elongation at break of the irradiated PET/PP film increase, while the penetration and sealing resistance decreased. In addition, the irradiated PET/LDPE/EVOH/LDPE film presented increase in the tensile strength on some radiation doses and decrease of the penetration and sealing resistance, except for sealing resistance at radiation dose of 15 kGy that resulted in a slight increase of ca 4%.
Medicinal plants i.e. dried seeds of myristica argentea, myristica fragrans, coriandrum sativum and foeniculum vulgare were stored for 0 and 6 months, with and without gamma irradiation at 5 kGy. No detectable changes were seen in infrared and UV spectra, GLC chromatograms and refraction indices of steam distilled, essential oils from the irradiated medicinal plants. The same results were also obtained from irradiated samples stored for 6 months at ambient conditions. Storage for 6 months caused significant changes in the gas liquid chromatograms and UV spectra of all samples compared to non-stored samples. The moisture content of all samples packed in polyethylene bags seems to be constant after 6 months of storage. No measurable changes were found in the amount of essential oil content caused by irradiation.
The results on 5 K irradiation available so far may be summarized as follows. (1) Increases of j/sub c/ following neutron irradiation occur only in conductors which are far from the optimal metallurgical treatments. (2) The changes of j/sub c/ following neutron irradiation and a thermal cycle to room temperature are small and in most cases comparable to the results obtained after 77 K irradiation. (3) The data available so far indicate that the degradation of j/sub c/ at 8 T is larger by about 5 to 10% than the corresponding changes at 5 T at a neutron fluence of 1.3 x 10/sup 22/ m/sup -2/ (E > 0.1 MeV). (4) The increase of Cu-resistivity is significant even after a thermal cycle to room temperature and requires design changes for a stable magnet operation.
A total of 86 experimental fuel pins with various fuel, liner, and cladding candidate materials have been irradiated in the Experimental Breeder Reactor-II (EBR-II) and the Fast Flux Test Facility (FFTF) reactor as part of the SP-100 fuel pin irradiation testing program. Postirradiation examination results from these fuel pin are key in establishing performance correlations and demonstrating the lifetime and safety of the reactor fuel system. This paper provides a brief description of the in-reactor fuel pin tests and presents the most recent irradiation data on the performance of wrought rhenium (Re) liner material and high density UN fuel at goal burnup of 6 atom percent (at. %). It also provides an overview of the significant variety of other fuel/liner/cladding combinations which were irradiated as part of this program and which may be of interest to more advanced efforts.
Two of eight differently prepared copper stabilizer samples, previously irradiated in the RTNS-II at LLNL, the IPNS-1 and the BSR at ORNL, have been irradiated to a fluence of 1.33 /times/ 10/sup 22/ n/m/sup 2/ at RTNS-II. During the course of the irradiation the samples were periodically removed (without warming) for measurements of the transverse magnetoresistance and returned for continued irradiation. This experiment extends the range of neutron-irradiation-induced resistivity by a factor of five over the previous experiments. A simple model is developed which reproduces the magnetoresistance results of all the experiments to an accuracy of 2.5%. 13 refs., 6 figs.
The invention refers a procedure of radiation dose control in irradiated tissues during electron-beam therapy. It aims at meeting the planned radiation dose for diseased tissues and taking care of the healthy ones. Therefore, the dose distribution required is determined before irradiation in consideration of such factors as energy-dependence of detector sensitivity, self-absorption within the tissue, and relative biological effectiveness. Furthermore, the expected intensity distribution of secondary quantum radiation excited in the irradiated tissue is calculated. A radiation detector for local resolution is used for registration. During irradiation the calculated intensity distribution is compared with the measured one. The invention is applicable in radiation therapy with monoenergetic electron beams.
Joint FAO/IAEA/WHO Expert Committee approved the use of radiation treatment of foods. Nowadays food packaging are mostly made of plastics, natural or synthetic, therefore effect of irradiation on these materials is crucial for packing engineering for food irradiation technology. By selecting the right polymer materials for food packaging it can be ensured that the critical elements of material and product performance are not compromised. When packaging materials are in contact with food at the time of irradiation that regulatory approvals sometimes apply. The review of the R-and-D and technical papers regarding material selection, testing and approval is presented in the report. The most information come from the USA where this subject is well elaborated, the International Atomic Energy Agency (IAEA) reports are reviewed as well. The report can be useful for scientists and food irradiation plants ...
Various control procedures have been suggested for reducing foodborne infectious diseases. Receiving considerable attention is irradiation. This report estimates the medical and wage (or productivity) benefits associated with prevention of five human diseases transmitted by beef, pork, and chicken. (These diseases can also be transmitted by other vectors, such as eggs, milk, and pets. But these sources are not included in the analysis.) All of these foodborne infectious diseases - salmonellosis, campylobacteriosis, trichinosis, tapeworm, and toxoplasmosis - could be significantly reduced by irradiating meat and poultry. The Food and Drug Administration (FDA) has just approved irradiation of pork to prevent trichinosis (50FR 29658-59) and is considering approval of irradiation of chicken to kill Salmonella. 22 references.
Materials for the construction of cold neutron sources must satisfy a range of demands. The cryogenic temperature and irradiation create a severe environment. Candidate materials are identified and existing cold sources are briefly surveyed to determine which materials may be used. Aluminum- and magnesium-based alloys are the preferred materials. Existing data for the effects of cryogenic temperature and near-ambient irradiation on the mechanical properties of these alloys are briefly reviewed, and the very limited information on the effects of cryogenic irradiation are outlined. Generating mechanical property data under cold source operating conditions is a daunting prospect. It is clear that the cold source material will be degraded by neutron irradiation, and so the cold source must be designed as a brittle vessel. The continued effective operation of many different cold sources at a number of ...
The degradation of irradiated human insulin in aqueous solutions was investigated in order to protect the protein against ionizing radiation. The influence of the drug concentration, excipients and irradiation temperature were studied.Aqueous solutions at pH 2 were irradiated by gamma rays or by accelerated electrons. Two different high-performance liquid chromatography (HPLC) methods were used: reverse-phase high-performance liquid chromatography (RP-HPLC)/UV and size exclusion liquid chromatography (SEC/UV) to investigate both the fragmentation and the formation of higher molecular weight proteins.In solution without excipients irradiated at ambient temperature at 10kGy, the loss of human insulin is almost complete. Addition of radio-protecting excipients (free radicals scavengers) and c...
Nano indentation analysis and transmission electron microscopy observation were performed to investigate a microstructural evolution and its influence on the hardening behavior in Fe-Cr alloys after an irradiation with 8 MeV Fe4+ ions at room temperature. Nano indentation analysis shows that an irradiation induced hardening is generated more considerably in the Fe-15Cr alloy than in the Fe-5Cr alloy by the ion irradiation. TEM observation reveals a significant population of the a0 dislocation loops in the Fe-15Cr alloy and an agglomeration of the 1/2a0 dislocation loops in the Fe-5Cr alloy. The results indicate that the a0 dislocation loops will act as stronger obstacles to a dislocation motion than 1/2a0 dislocation loops.
It has recently been shown that the superconducting properties of Nb-base A-15 compounds, A_3B, are severely degraded when exposed to high-energy (E>1 MeV) neutron irradiation at ambient reactor temperatures. In each case, superconducting transition temperatures, Tsub(c), and the Bragg Williams order parameters, S, were observed to decrease steadily with irradiations in excess of 10"1"8 nvt. During irradiation the A-15 structure is retained and subsequent isothermal annealing restores almost completely the compound's original Tsub(c) value. In this letter a correlation between B atom diameter and the recovery rates of Tsub(c) for the irradiated materials Nb_3Ge, Nb_3Ga, Nb_3Al and Nb_3Sn is reported. (Auth.).
Black pepper, white pepper, red pepper, ginger and turmeric were irradiated with 10 MeV electrons from a linear accelerator to a dose of 100 kGy and radioactivity was measured in order to estimate induced radioactivity in the irradiated foods. Induced radioactivity could not be detected significantly by #gamma#-ray spectrometry in the irradiated samples except for spiked samples which contain some photonuclear target nuclides in the list of photonuclear reactions which could produce radioactivity below 10 MeV. From the amount of observed radioactivities of short-lived photonuclear products in the spiked samples and calculation of H_5_0 according to ICRP Publication 30, it was concluded that the induced radioactivity and its biological effects in the 10 MeV electron-irradiated natural samples were negligible in comparison with natural radioactivity from "4"0K contained in the samples. (author).
Ionizing radiation has been used to treat poultry to remove harmful microorganisms, mainly Salmonella, which contaminates chicken, goose and other fresh and frozen poultry. This microorganism is sensitive to low dose radiation. Thus, irradiating these foods with doses between 1 to 7 kGy results in a large reduction of bacteria. Since it is necessary to determine whether irradiation has occurred and to what extend, this work studied the signal produced by ionizing radiation within the hard crystalline matrix of chicken`s bone to establish a control method. Chicken`s drumsticks were irradiated and bones separated from flesh were lyophilized and milled. ESR spectrum was then obtained. The ESR signal increased linearly with dose over the range 0.25 to 8.0 kGy. Free radicals evaluated during 30 days after irradiation showed stable in this period. (Author).
In FY1994, JMTR was in operation during 4 operation cycles with low enriched Uranium(LEU,20%) fuel for irradiation study of nuclear fuels and materials and for radioisotope production. Irradiation studies were carried out using capsules, Oarai Gas Loop-1(OGL-1), Oarai Shroud Facility(OSF-1) and hydraulic rabbits irradiation facilities in support of LWR, FBR, HTTR and thermonuclear reactor. Irradiation studies on blanket materials were intensively carried out. Power ramping tests were carried out and the future program is under consideration. For R and D works, neutron spectrum evaluation technology, re-instrumentation technique for irradiation fuel rod, remote controlled SEM apparatus and examination technique with miniaturized specimens were successfully developed. (author).
The change of superconducting properties after neutron irradiation in A-15 compounds such as Nb_3Sn. Nb_3Al. V_3Ca and V_3Si has been examined. Using the model based on the damage function, the change of transition temperature corresponding to an arbitrary irradiation dose within about 10"2"0n/cm"2 can be predicted with an accuracy of several percent for Nb_3Al. Nb_3Sn and V_3Si if experimental data, namely a pair of irradiation dose and transition temperature, is given. The calculation of transition temperature of neutron irradiated A-15 compounds is much more straightforward than in the case of Pande's model. (author).
The effects of gamma irradiation at 0.2#approx#0.4 Mrad and condition for processing of buckwheat noodles on sensory quality and physical properties were investigated. The results were as follows: (1) Sensory evaluation of buckwheat noodles, prepared with the 70 % ratio of buckwheat flour, was decreased according to an increase of irradiation dose of buckwheat flour. Hardness and adhesiveness of buckwheat noodles caused by irradiation should be given large effect to the texture. Elasticity of buckwheat noodles was linearly decreased with increasing of irradiation dose of buckwheat flour, and elasticity of buckwheat noodles was decreased about 15 % by an increase of irradiation dose at 0.3 Mrad. (2) Maximum torque in Farinograph test was linearly decreased with increasing of irradiation dose of buckwheat flour, and maximum torque was decreased about 3 % by ...
The Radiation Technology Center from IPEN-CNEN/SP, Brazil, developed a revolutionary design and national technology, a small-sized continuous run and multipurpose industrial gamma irradiator, to be used as a demonstration facility for manufacturers and contract service companies, which need economical and logistical in-house irradiation system alternatives. Also, to be useful for supporting the local scientific community on development of products and process using gamma radiation, assisting the traditional and potential users on process validation, training and qualification of operators and radioprotection officers. The developed technology for this facility consists of a continuous tote box transport system, comprising a single concrete vault, where the automated transport system of products inside and outside of the irradiator utilizes a rotating door, integrated with the shielding, avoiding the traditional maze ...
In order to protect food from pathogenic microorganisms as well as to increase its shelf life while keeping sensorial properties (e.g. odor and taste), once the latter are one of the main properties required by spice buyers, it is necessary to analyze volatile formation from irradiation of medicinal and food herbs. The aim of the present study was to analyze volatile formation from Co irradiation of Laurus Cinnamomum, Piper Nigrum, Origanum Vulgare and Myristica Fragans. Possible changes on the odor of these herbs are evaluated by characterizing different radiation doses and effects on sensorial properties in order to allow better application of irradiation technology. l he samples have been irradiated in plastic packages by making use of a {sup 60}Co Gamma irradiator. Irradiation doses of 0, 5, 10, 15, 20 and 25kGy have been tested. For the analysis of the ...
Short note. The World Health Organization (WHO) has taken aim at critics of irradiated food, claiming that the process has the potential to reduce the incidence of foodborne diseases such as salmonellosis, to cut postharvest food losses and to provide a wider variety of foods for consumers. 'The unwarranted rejection of this process, often based on lack of understanding of what food irradiation entails, may hamper its use in those countries which may benefit most', Dr. Jean-Paul Jardel, WHO's assistant director-general, argued following a recent international conference on the subject. Critics, including Canadians, has opposed food irradiation for years, claiming that more needs to be known about its effects. WHO said the 'vast majority' of the 54 national delegations at the conference supported use of the technology on foods ranging from grain and potatoes to poultry, tropical fruit and strawberries. WHO wants governments ...
The effect of ionizing radiation (2, 5, and 10 KGy of gamma rays) on muscle ultrastructure of grass shrimps (Penaeus monodon Fabricius) tails at ambient or frozen (-18{sup 0}C) temperature was investigated by transmission electron microscopy (TEM). No significant change was found in muscle ultrastructure of shrimp meat irradiated at doses of 2 or 5 KGy and then stored at 4{sup 0}C for 0 and 8 days. However, in shrimps which were irradiated at ambient temperature at a dose of 10 KGy, the margin of A-band of the myofibrils in longitudinal sections exhibited an irregular zig-zag pattern. In cross section some myosin filaments in the A-band regions were missing. A possible interpretation of these results would be that 10 KGy gamma irradiation dose at ambient temperature depolymerized myosin in the A-band from the tail of thick filament. Actin damage was also observed in some cross sections. Irradiation ...
The effect of ionizing radiation (2, 5, and 10 KGy of gamma rays) on muscle ultrastructure of grass shrimps (Penaeus monodon Fabricius) tails at ambient or frozen (-18"0C) temperature was investigated by transmission electron microscopy (TEM). No significant change was found in muscle ultrastructure of shrimp meat irradiated at doses of 2 or 5 KGy and then stored at 4"0C for 0 and 8 days. However, in shrimps which were irradiated at ambient temperature at a dose of 10 KGy, the margin of A-band of the myofibrils in longitudinal sections exhibited an irregular zig-zag pattern. In cross section some myosin filaments in the A-band regions were missing. A possible interpretation of these results would be that 10 KGy gamma irradiation dose at ambient temperature depolymerized myosin in the A-band from the tail of thick filament. Actin damage was also observed in some cross sections. Irradiation damage of ...
The fading of irradiated and natural blue-colored pearls was investigated in this experiment. Thirty natural blue-colored pearls and sixty irradiated blue-colored pearls were used. Some of them were placed at a light position of RT. Another pearls were placed at a dark position of 50"0C. The irradiated pearls placed at a light position of RT didn't show remarkable fading in their color in 294 days. But the natural blue-colored pearls showed a little recovery from 4% to 8% in reflection factors in 223 days at RT. The irradiated pearls placed at a dark position of 50"0C showed the recovery from 9% to 14% in 264 days independently of irradiation times. The natural blue-colored pearls also showed the bleaching from 5% to 10% in reflection factor in 86 days at 50"0C. Both irradiated and natural blue-colored pearls hardly showed their remarkable changes in their ...
The photon rupture method, by which oxide film and metal are removed by focused pulsed Nd-YAG laser beam irradiation, was applied to form artificial micro-pits in Zn-5 mass% Al alloy-coated steel. The zinc alloy-coated layer was removed by pulsed laser irradiation treatment for about one second in a neutral buffer solution with NaCl. The rest potential transient with the laser treatment was measured. In the early stage of the laser treatment the rest potential of zinc alloy-coated steel changed to the negative direction immediately after every irradiation of a laser pulse and then returned to the previous value. However, after the steel substrate was exposed to the solution, the rest potential moved to the positive direction immediately after every irradiation of a laser pulse and then returned to the previous value. The amplitude and duration of the potential change after the laser ...
The fading of irradiated and natural blue-colored pearls was investigated in this experiment. Thirty natural blue-colored pearls and sixty irradiated blue-colored pearls were used. Some of them were placed at a light position of RT. Another pearls were placed at a dark position of 50/sup 0/C. The irradiated pearls placed at a light position of RT didn't show remarkable fading in their color in 294 days. But the natural blue-colored pearls showed a little recovery from 4% to 8% in reflection factors in 223 days at RT. The irradiated pearls placed at a dark position of 50/sup 0/C showed the recovery from 9% to 14% in 264 days independently of irradiation times. The natural blue-colored pearls also showed the bleaching from 5% to 10% in reflection factor in 86 days at 50/sup 0/C. Both irradiated and natural blue-colored pearls hardly showed their ...
Target vessel materials used in spallation neutron source will be exposed to proton and neutron irradiation and mercury immersion environments. In order to evaluate the surface degradation of the vessel candidate materials due to such environment, the triple-ion beam irradiation taking the spallation reaction into account and mercury immersion tests were carried out. Mechanical properties of the gradient surface layer were evaluated by the inverse analysis with multi-layer model that considers distribution of surface characteristic was applied to the load and depth curves measured by using the instrumented indentation machine. Transmission electron microscopic observations were performed to evaluate the changes of microstructure in irradiated surface layer using focused ion-beam cut micro-specimen. The mechanical properties distributions in the surface layer were evaluated quantitatively and the changes in microstructures ...
Tensile specimens of the normalized and tempered fully martensitic steel DIN 1.4914 were helium implanted up to 340 appm within the temperature range 300-720/sup 0/C using a 104 MeV alpha particle beam. The high He/damage ratio of 1850 appm He/dpa allowed to determine the effect of helium on material properties. After irradiation tensile strength and ductility were investigated mainly at test temperatures equal to the irradiation temperatures. While short time irradiations with helium contents up to 100 appm have shown no visible effect on the tensile behaviour at all temperatures investigated, long time irradiations reduced the material strength at irradiation temperatures above about 440/sup 0/C. This irradiation induced softening obscured the predicted minor hardening effect of the observed He-bubbles completely and increases with ...
Marketing of minimally processed vegetables (MPV) are gaining impetus due to its convenience, freshness and apparent health effect. However, minimal processing does not reduce pathogenic microorganisms to safe levels. Food irradiation is used to extend the shelf life and to inactivate food-borne pathogens. In combination with minimal processing it could improve safety and quality of MPV. A microbiological screening method based on the use of direct epifluorescent filter technique (DEFT) and aerobic plate count (APC) has been established for the detection of irradiated foodstuffs. The aim of this study was to evaluate the applicability of this technique in detecting MPV irradiation. Samples from retail markets were irradiated with 0.5 and 1.0 kGy using a {sup 60}Co facility. In general, with a dose increment, DEFT counts remained similar independent of the irradiation while APC ...
Here, we show that the consequences of deficient micronutrient (β-carotene) intake during larval stages of Manduca sexta are carried across metamorphosis, affecting adult behaviour....Full Text Available
Various factors affecting the aggregation of Actinomyces naeslundii strain 12104 were studied. When the pH of glucose-supplemented growth medium fell below 5.5, the cells aggregated and formed microbial...Full Text Available
Knowledge of factors affecting variation in birth weight is especially important given the relationship of birth weight to neonatal and adult health. The present study utilises two large contemporary...Full Text Available
The meiotic spindle in the oocyte is composed of microtubules and plays an important role during chromosome alignment and separation at meiosis. Polarized light microscopy (PLM) could be useful for a non-invasive evaluation of the meiotic spindle and may allow removal of nuclear structures without fluorochrome staining and ultraviolet exposure. In this study, PLM was used to assess its potential application in porcine reproductive technologies. The objectives of the present study were to assess the efficiency of PLM to detect microtubule-polymerized protein in in vitro-matured porcine oocytes; to examine its effects on the oocyte developmental competence; to select oocytes based on the presence of the meiotic spindle detected by PLM; and to assess the efficiency oocyte enucleation assisted...
A scheme of evaluating a generalized three-photon excitation cross section #sigma#/sub (3)/ in neutral atomic argon at 3144.67 A is outlined. Three photons at this wavelength can excite the neutral argon atoms from the ground 3p"6 "1S_0 state to the 3p"54s'[1/2]_1"0 state. The fourth photon will ionize the argon atoms. Assuming linear polarization of the incident laser radiation, contributions from several channels in various energy-level schemes are summed in the evaluation of the transition probability. For a laser linewidth of #DELTA##lambda#/sub L/ = 1 A, our maximum numerical value of the computed result for the three-photon excitation cross section is #sigma#/sub (3)/ = 1.414 x 10/sup -80/ cm"6 s"2. .AE.
The effects of eight chemicals on the inactivation rate of ultraviolet radiation on the colony building capabilities of two strains of Saccharomyces cervisae - a wild type strain and a mutant deficient in excision repair - were studied. The insecticide methoxychlor, the herbicide 2,4-dichlorophenoxyacetic acid, the fungicide pentachlorophenol and its metabolite tetrachlorohydroquinone, as well as the chemicals acrylonitrile and 2,3-dichloro-1-propene have no significant impact on the effects of UV radiation in Saccharomyces cerevisae. Depending on the concentration, trichloroethylene increases the sensitivity to UV radiation. The herbicide paraquat provides efficient protection against UV radiation at concentrations where a toxic effect cannot be observed even without UV. The results were rather similar for both strains. (orig.).
Ultraviolet photoelectron spectra were measured for vanadyl phthalocyanine (VOPc) ultrathin films prepared on graphite to study effects of the molecular orientation and the electric dipole layer on the organic electronic states. VOPc has a permanent electric dipole perpendicular to the molecular plane, hence a well-defined electric dipole layer could be intentionally prepared by using the oriented monolayer. The observed binding-energy difference of the highest occupied molecular orbital (HOMO) bands between the oriented monolayer and the double layer was found to agree with the vacuum level shift, leading to a conclusion that the molecular energy level with respect to the substrate Fermi level is changed when the molecule is in the electric dipole layer.
We present experimental studies on the photoionization and photodissociation processes (photodestruction) of gaseous amino acids and nucleobases in interstellar and interplanetary radiation conditions analogs. The measurements have been undertaken at the Brazilian Synchrotron Light Laboratory (LNLS), employing vacuum ultraviolet (VUV) and soft X-ray photons. The experimental set up basically consists of a time-of-flight mass spectrometer kept under high vacuum conditions. Mass spectra were obtained using photoelectron photoion coincidence technique. We have shown that the amino acids are effectively more destroyed (up to 70-80%) by the stellar radiation than the nucleobases, mainly in the VUV. Since polycyclic aromatic hydrocarbons have the same survival capability and seem to be ubiquitous in the ISM, it is not unreasonable to predict that nucleobases could survive in the interstellar medium and/or in comets, even as a stable cation.
The light-emitting properties of cubic silicon carbide films grown by vacuum vapor phase epitaxy on Si(100) and Si(111) substrates under conditions of decreased growth temperatures (T gr ? 900?700?C) have been discussed. Structural investigations have revealed a nanocrystalline structure and, simultaneously, a homogeneity of the phase composition of the grown 3C-SiC films. Photoluminescence spectra of these structures under excitation of the electronic subsystem by a helium-cadmium laser (?excit = 325 nm) are characterized by a rather intense luminescence band with the maximum shifted toward the ultraviolet (?3 eV) region of the spectral range. It has been found that the integral curve of photoluminescence at low temperatures of measurements is split into a set of Lorentzian components. Th...
The authors study the processes {gamma}e {r{underscore}arrow} {gamma}e and {gamma}{gamma} {r{underscore}arrow} {gamma}{gamma}, in the context of the proposal for Weak Scale Quantum Gravity (WSQG) with large extra dimensions. With an ultraviolet cutoff M{sub S} {approximately} 1 TeV for the effective gravity theory, the cross sections obtained for these processes at the Next Linear Collider (NLC), with the e{gamma} an {gamma}{gamma} options, deviate from the predictions of the Standard Model significantly. The results suggest that, for typical proposed NLC energies and luminosities, the predictions of WSQG can be tested in the range 1 TeV {approx{underscore}lt} M{sub S} {approx{underscore}lt} 10 TeV, making e{gamma} an {gamma}{gamma} colliders important tools for probing WSQG.
A position-sensitive event-counting electronic readout system for microchannel plates (MCPs) is described that offers the advantages of high spatial resolution and fast time resolution. The technique relies upon a four-quadrant electron-collecting anode located behind the output face of the microchannel plate, so that the electron cloud from each detected event is partly intercepted by each of the four quadrants. The relative amounts of charge collected by each quadrant depend on event position, permitting each event to be localized with two ratio circuits. A prototype quadrant anode system for ion, electron, and extreme ultraviolet imaging is described. The spatial resolution achieved, approx. =10 ..mu.., allows individual MCP channels to be distinguished. (AIP)
A position-sensitive event-counting electronic readout system for microchannel plates (MCPs) is described that offers the advantages of high spatial resolution and fast time resolution. The technique relies upon a four-quadrant electron-collecting anode located behind the output face of the microchannel plate, so that the electron cloud from each detected event is partly intercepted by each of the four quadrants. The relative amounts of charge collected by each quadrant depend on event position, permitting each event to be localized with two ratio circuits. A prototype quadrant anode system for ion, electron, and extreme ultraviolet imaging is described. The spatial resolution achieved, approx. =10 #mu#, allows individual MCP channels to be distinguished.
Hemolysis induced by long-wave ultraviolet radiation (UVA) and 8 different commercial tetracycline derivatives was studied in a model using human red blood cells. Demethylchlortetracycline and doxycycline were shown to have pronounced hemolytic properties causing 88% and 85% hemolysis, respectively, at a concentration of 50 micrograms/ml and 72 J/ cm2 of UVA. Tetracycline, oxytetracycline, and chlortetracycline caused maximally 18% hemolysis at 200 micrograms/ml and lymecycline only 7% at 100 micrograms/ml. Methacycline showed intermediate hemolytic effect of 36% at 200 micrograms/ml. Minocycline had no hemolytic effect whatsoever. These experimental data correlate very well with clinical reports and comparative phototoxicity trials in humans. Photohemolysis may thus be of value for predicting tetracycline phototoxicity.
Luminescence properties of SiAlON phosphors codoped with Ca and Yb were investigated by changing the host lattice composition. These modifications of the host lattice were obtained by replacing Si-N bonds by Al-N and Al-O bonds. Their photoluminescence (PL) and cathodoluminescence (CL) properties were measured and compared with each other. PL allows observing the influence of the host lattice modifications by measuring wider areas. CL can excite all luminescent centers, in particular the UV luminescence centers, even if their amount is small. Thus, two additional peaks in the ultraviolet and infrared regions were observed in CL, which is not observed by PL. This work suggests that the combination of PL and CL gives more understanding about the luminescence of SiAlON phosphors, in particular the role of the secondary phases on their properties.
Cold spray was employed as a novel low temperature approach to deposit titanium dioxide (TiO{sub 2}) photocatalytic film. The film microstructure was characterized using X-ray diffraction and scanning electron microscopy. The photocatalytic performance was examined through acetaldehyde degradation under ultraviolet illumination. Results showed that TiO{sub 2} film was successfully deposited on substrate surface through cold spray. The film thickness reached up to 15 {mu}m. The film presented a rough surface and porous structure. Owing to the low temperature of spray powder, no phase and particle size changes occurred to TiO{sub 2} during deposition. It was found that the cold-sprayed TiO{sub 2} film was active for photodegradation of acetaldehyde.
The kinetics of alkaline hydrolysis of methylparathion was studied at different temperatures (0-50 Centigrade) in the p H range of 8-12 by ultraviolet-visible absorption spectroscopy. Optimum p H and wavelength conditions were defined to carry out the simultaneous determination of methylparathion and one of its hydrolysis product, paranitrophenol, in buffered aqueous medium. Based on the experimental data and the mathematical equation of the kinetics, a rate constant (k) of first-order and an activation energy (Ea) of 9.2 Kcal/mol, were estimated. (Author) activation energy (Ea) of 9.2 Kcal/mol, were estimated. (Author)
We review and extend in several directions recent results on the asymptotic safety approach to quantum gravity. The central issue in this approach is the search of a Fixed Point having suitable properties, and the tool that is used is a type of Wilsonian renormalization group equation. We begin by discussing various cutoff schemes, i.e. ways of implementing the Wilsonian cutoff procedure. We compare the beta functions of the gravitational couplings obtained with different schemes, studying first the contribution of matter fields and then the so-called Einstein-Hilbert truncation, where only the cosmological constant and Newton's constant are retained. In this context we make connection with old results, in particular we reproduce the results of the epsilon expansion and the perturbative one loop divergences. We then apply the Renormalization Group to higher derivative gravity. In the case of a general action quadratic in curvature we recover, within certain approximations, the known ...
The intrinsic fluorescence of clear amniotic fluid from third-trimester pregnancy is reported. The fluorescence intensity peaked at 405 nm when excited by ultraviolet light in the range of 310 to 360 nm. All of the 33 samples tested fluoresced, and their emission spectrum had the same shape, varying only in magnitude. Changing sample temperature (20 to 50 C) and sample pH (7.2 to 7.7) had little effect on the emission spectrum. The same fluorescence, with higher intensity, was observed when some newborn urine was tested. The fluorescence of amniotic fluid may provide a new tool to determine fetal age, fetal organ maturation, and fetal distress. (author).
The authors report experimental results on a high gradient 17 GHz RF photocathode gun. The photocathode RF gun is a novel electron beam source intended to meet the requirements set by future high-energy linear colliders and next generation free electron lasers. A coupled pair of pillbox TM{sub 010}-like resonators is excited by sidewall coupled microwaves at 17 GHz. A picosecond ultraviolet laser pulse illuminates one wall of the structure at the axis of symmetry. Electrons are released by the photoelectric effect and are accelerated by the electric field of the microwaves in the cavity. The high frequency of operation raises the RF breakdown limit allowing strong electric fields to be used. In turn, the intense fields result in rapid acceleration of the electrons to relativistic speeds and reduced space charge induced emittance growth.
Iron nanoparticles were produced using extracts of green tea leaves (GT-Fe NPs). The materials were characterized using TEM, SEM/EDX, XPS, XRD, and FTIR techniques and were shown to contain mainly iron oxide and iron oxohydroxide. The obtained nanoparticles were then utilized as a Fenton-like catalyst for decolorization of aqueous solutions containing methylene blue (MB) and methyl orange (MO) dyes. The related experiments investigated the removal kinetics and the effect of concentration for both MB and MO. The concentrations of dyes in aqueous solution were monitored using ultraviolet-visible (UV-vis) spectroscopy. The results indicated fast removal of the dyes with the kinetic data of MB following a second order removal rate, while those of MO were closer to a first order removal rate. T...
Plasma polymerization of aniline is carried out in a radiofrequency plasma reactor and the effect of polymerization time is examined in the structural, optical and optoelectronic properties of deposited films. Conjugated structures of polyaniline like films are obtained with unique and broad optical absorption band in the ultraviolet and entire visible region. The width of the absorption band increases and hence the optical band gap decreases with polymerization time. The optical constants are extracted by Swanepoel method and the optical dispersion parameters are determined by employing the Wemple-DiDomenico single oscillator model. The films exhibit similar thermal stability in air and argon atmosphere in the region of interest for optoelectronic applications. The photoluminescence study...
Organic/metal interface properties are of high interest for the application of molecular (sub)monolayers to modify surface properties. They are applied for, e.g., molecular electronics, chemical sensing, or the tuning of injection barriers in organic electronic devices. We present a joint theoretical and experimental study of F{sub 4}TCNQ adsorbed on Cu(111). The electronic and structural properties were determined by ultraviolet photoelectron spectroscopy (UPS) and X-ray standing wave (XSW) measurements. To better understand the complex process of binding, we modelled the system using density-functional theory. We find forward-donation from the lone pairs of the molecule into metallic states and back-donation from the metal into the LUMO of the molecule. The data on Cu(111) are compared to F4TCNQ on Au(111) and Ag(111) as well as to investigations of pyrenetetraone on various coinage metals.
#epsilon#_m(Ce"4"+) values of the ceric-cereus system have been measured and the experimental procedure is described. Both routine titration method and electrochemical measurement were used. Some interference factors, such as ultraviolet, acidity and temperature, were studied as well. The temperature coefficient of #epsilon#_m(Ce"4"+) value in this experiment is about -0.1% degree C"-"1. A statistic analysis was made for 24 experimental values of #epsilon#_m(Ce"4"+) and a Gaussian distribution was found. Ultimately, an average molar extinction coefficient of 553.2 +- 1.3 m"2#centre dot#mol"-"1 was obtained at #approx#320 nm in 0.4 mol/L H_2SO_4 system, with a relative standard deviation of 0.24% (95% confidence level) and a total uncertainty of 1.5%.
A number of difficult technical challenges need to be solved in the fields of accelerator and free-electron laser (FEL) technologies in order to build an X-ray FEL. One of the tasks well suited to the Advanced Photon Source Low Energy Undulator Test Line (LEUTL) is to take the intermediate step of solving some of the problems of single-pass FEL operation in the ultraviolet range. The existing Advanced Photon Source (APS) linac, in addition to its role of supply positrons for the APS storage ring, will also be used to generate the particle beam for the LEUTL. Here, the design of the magnetic system for the high gain soft x-ray free electron laser is described.
The construction and the development of a UV free electron laser have been started under the cooperation of Nihon U, KEK, PNC, ETL and Tohaku U. The project requires a 100MeV S-band electron linear accelerator to expand the oscillation of FEL using fundamental mode to the UV region. The injection system consists of a thermionic RF-gun with a LaB cathode and an {alpha} magnet for magnetic bunching. We are studying to reduce the back-bombardment electrons to realize the macropulse length of 20{mu}sec. Electron beams, up to the energy of 100MeV, are injected into the optical oscillators. Changing the accelerating energy and/or undulator parameters, this system will cover the range from infrared to ultraviolet for the applications in various fields.
Paper presents conceptual design of free electron laser (FEL) complex for industrial applications. The FEL complex consists of three. FEL oscillators with the optical output spanning the infrared (IR) and ultraviolet (UV) wave-lengths (#lambda# = 0.3...20 #mu#m) and with the average output power 10 - 20 kW. The driving beam for the FELs is produced by a superconducting accelerator. The electron beam is transported to the FELs via three beam lines (125 MeV and 2 x 250 MeV). Peculiar feature of the proposed complex is a high efficiency of the. FEL oscillators, up to 20 %. This becomes possible due to the use of quasi-continuous electron beam and the use of the time-dependent undulator tapering.
Background. Reports of positive patch test and photopatch test reactions to the chemical ultraviolet filter octocrylene have increased during the last decade. Little is known about the reason for octocrylene's allergenic activity. Objectives. To present and discuss the results of patch tests and photopatch tests with octocrylene, and to investigate the possible cause of its allergenic properties. Methods. Results of patch tests and photopatch tests with octocrylene in patients with adverse skin reactions to sunscreen products and/or ketoprofen were collected. The allergenic potency of octocrylene was investigated in the murine local lymph node assay (LLNA). Chemical reactivity assays were used to mimic octocrylene's interaction with biomolecules. Results. We report 23 cases of positive tes...
Composting of sawdust and paper mill sludge, using a 'Kneer' process reactor, was studied in an attempt to elaborate upon organic matter transformation during the process and to define parameters to measure the compost maturity level. Temperature, electron paramagnetic resonance data, ash and C, H, N and S contents, and a spectroscopic method using ultraviolet-visible (UV-VIS) for alkaline (pH = 8.5) and solid samples was used to study the maturity of the compost samples. These parameters were measured in 6 humic acids extracted from the compost samples during 29 days. The results of this work show that the 'Kneer' process is efficient in transforming ligno-celulitic residues in a short time (29 days), into an organic fertilizer material with application perspectives (author)
Absorption coefficient data are presented for molecular oxygen at temperatures between 1100 and 2000K and discrete wavelengths between 211 and 235nm. Measurements were made behind reflected shock waves using broad-linewidth ultraviolet laser radiation generated from a frequency-quadrupled, tunable, pulsed Ti:Sapphire laser. Test mixtures consisting of 15% O"2, 15% He and balance Ar were used to minimize the influence of vibrational relaxation on the reflected shock temperature. The experimental results are in good agreement with theoretical calculations and confirm that discrete features from the Schumann-Runge system dominate between 211 and 235nm at temperatures higher than 1100K.
Spiral orbit tribometry friction tests performed on Ni-rich Ni55Ti45 titanium ball bearings indicate that this alloy is a promising candidate for future aerospace bearing applications. Microstructural characterization of the bearing specimens was performed using transmission electron microscopy and energy dispersive spectroscopy, with NiTi, Ni4Ti3, Ni3Ti, and Ni2Ti4Ox phases identified within the microstructure of the alloy. Density functional theory was applied to predict the electronic structure of the NixTiy phases, including the band structure and site projected density of states. Ultraviolet photoemission spectroscopy was used to verify the density of states results from the density functional theory calculations, with good agreement observed between experiment and theory.
Studies of asphalt emulsion sealants conducted by the Pacific Northwest Laboratory have demonstrated that the sealants are effective in containing radon and other potentially hazardous material within uranium tailings. The laboratory and field studies have further demonstrated that radon exhalation from uranium tailings piles can be reduced by greater than 99% to near background levels. Field tests at the tailings pile in Grand Junction, Colorado, confirmed that an 8-cm admix seal containing 22 wt% asphalt could be effectively applied with a cold-mix paver. Other techniques were successfully tested, including a soil stabilizer and a hot, rubberized asphalt seal that was applied with a distributor truck. After the seals were applied and compacted, overburden was applied over the seal to protect the seal from ultraviolet degradation.
Studies of asphalt emulsion sealants have demonstrated that the sealants are effective in containing radon and other potentially hazardous material within uranium tailings. The laboratory and field studies have further demonstrated that radon exhalation from uranium tailings piles can be reduced by greater than 99% to less than background levels. Field tests at the tailings pile in Grand Junction, Colorado confirmed that an 8-cm admix seal containing 22 wt % asphalt could be effectively applied with a cold-mix paver. Other techniques were successfully tested, including a soil stabilizer and a hot, rubberized asphalt seal that was applied with a distributor truck. After the seals were applied and conpacted, overburden was applied over the seal to protect the seal from ultraviolet degradation. 14 figures.
For the purpose of solving the limitations such as shape and dimension for magnetic compact fabricated by conventional anisotropic forming under magnetic orienting field, the feasibility of a new magnetic forming process was studied. Ferrite powder mixed with UV resin was compacted in the die mold and followed by alignment under the magnetic field. Effects of viscosity of UV resin and forming condition on magnetic characteristics of the compact was investigated. Maximum degree of alignment for the ferrite powder reached to 0.826. It was predicted that the proposed method had make it possible to fabricate a high performance magnet having the anisotropic alignment of the magnetic powder. The UV resin is desirable to have low viscosity, good properties such as formability and configuration stability for the compact and also parting- ability between the metal mold and the compact. (author)
An electrochemical biosensor for determination of hydrogen peroxide (H2O2) was fabricated, based on the electrostatic immobilization of horseradish peroxidase (HRP) with one-dimensional gold nanowires (Au NWs) and TiO2 nanoparticles (nano-TiO2) on a gold electrode. The nano-TiO2 can give a biocompatible microenvironment and compact film, and the Au NWs can provide fast electron transferring rate and greatly add the amount of HRP molecules immobilized on the electrode surface. Au NWs were characterized by ultraviolet?visible spectra and transmission electron microscope. The electrode modification process was probed by cyclic voltammetry and electrochemical impedance spectroscopy. Chronoamperometry was used to study the electrochemical performance of the resulting biosensor. Under optimal co...
We report on characterization of a set of AlGaN/GaN multiple-quantum-well (MQW) photodetectors. The model structure used in the calculation is the p-i-n heterojunction with 20 AlGaN/GaN MQW structures in i-region. The MQW structures have 2nm GaN quantum well width and 15nm AlxGa1-xN barrier width. The cutoff wavelength of the MQW photodetectors can be tuned by adjusting the well width and barrier height. Including the polarization field effects, on increasing Al mole fraction, the transition energy decreases, the total noise increases, and the responsivity has a red shift, and so the detectivity decreases and has a red shift.
A novel liquid phase alkylation of aniline with methanol over Zn/Cu salts modified kaolin assisted with a pair of porous carbon electrode in slurry-bed reactor under constant current intensity, room temperature and atmospheric pressure was reported. The Zn/Cu salts modified kaolin catalysts were synthesized and characterized by infrared spectrometer (IR), powder X-ray diffraction (XRD) and scanning electron microscopy (SEM), which showed that the transition metals were completely supported on kaolins structure and formed a pored one. The effect parameters, such as initial pH, electrolysis time, metal ratio with kaolin and salts composition in this electrochemical catalytic system, were studied. The procedure was inspected by ultraviolet-visible spectrum (UV-vis), and the product distributi...
Effect of helium and hydrogen production on radiation-hardening of F82H irradiated by dual or triple beam condition were investigated. The specimens used were four types of ferritic martensitic steels of F82H-std (Fe-8Cr-2W-0.2V-0.04Ta-0.1C) steels tempered at 750degC for 60 minutes, 20% cold worked F82H steel, F82H tempered for 10 minutes and non-tempered F82H steels. The irradiation was performed at 450degC to 50 dpa under simultaneous dual beams of 10.5 MeV Fe"3"+ and 1.05 MeV He"+ or triple beams of those and 380 keV H"+ ions. The ratios of He (appm)/dpa and H(appm)/dpa were 15 nad 15 (or 150) for dual and triple ion beams. The hardness of the irradiated specimens measured at room temperature using a micro indentation after the irradiations. The hardness in these F82H steels irradiated at 450degC to 18 dpa under triple beam irradiation was harder than that ...
Ecosystems worldwide are experiencing unprecedented nitrogen enrichment through fertilization and pollution. While longterm ecological consequences are difficult to predict, it seems that plants and animals adapted to nitrogen-limited environments are at particular risk from these changes. This report summarizes the limited body of literature which addresses this important topic. From a herbivoreAes perspective, fertilization increases the nutritional quality of host plant tissues. In some cases fertilization has lead to decreased production of defensive compounds. How this affects populations of insects is unclear because fertilization affects not only herbivores but their natural enemies. This report outlines how fertilization affects tree processes such as growth, photosynthesis, and production of defensive compounds. The many factors that affect insect repsonse to fertilization and the difficulties ...
Thermal diffusivity was measured with a laser flash method up to 2000 K for UO_2 pellets irradiated in a commercial reactor. Measurements were done on micro samples of disks (2 mm diameter) or regular prisms (1.5 or 2 mm square cross sections). Thermal diffusivity degraded on extending burnup in agreement with reported values for UO_2 irradiated in test reactors, and it showed hysteresis during the laser flash experiments. Thermal diffusivity began to recover above 750 K and almost completely recovered above 1400 K, which corresponded with the reported radiation damage recovery. The obtained data were in agreement with predictions applying the thermal conductivity expression for irradiated UO_2 proposed by Amaya and Hirai. The sample experiencing power ramp showed higher thermal diffusivity than that of the base irradiated sample and had no obvious hysteresis. This suggested that the radiation damage ...
Samples from 314 broiler chickens at 2 months age were analyzed for blood serum level of lysozyme and 311 of them were analyzed also for activity of alternative path-way of complement activity (APCA). Chickens were hatched from eggs, irradiated immediately before incubation with different doses of gamma-rays using Rocus M device - group 1 - control (non irradiated), and groups 2, 3 and 4 - irradiated with doses of 0.15, 0.30 and 0.60 Gy, respectively. Lysozyme concentration was highest for the control group, and for the experimental ones it was lower (p<0.001) which is an indication of the strongly negative effect of gamma-rays on this indicator. For APCA the oppsite relationship was observed - increasing of its activity with increasing of irradiation dose (from p<0.05 to p<0.001) which gave reason to suggest that this phenomenon is due to the irradiation. 12 refs., 2 tabs. ...
Active oxygens produced by low-dose irradiation can induce the synthesis of proteins involved in the active oxygen reduction path and can activate the chemical self-defense mechanisms in vivo, which can alleviate the injuries caused by active oxygens themselves. The following findings suggests that it is not only by low-dose irradiation that can induce the responses described above but also by any physical and/or chemical stresses which can produce small amount of active oxygens in vivo. 1. X-irradiation with 0.5 Gy and/or water immersion and restraint induced heat shock protein (HSP)70 in rat stomach cells. HSP70 was also induced in adrenal cells by paraquat administration. 2. The SOD activity in pancreas of rat significantly increased by #gamma#-irradiation with 0.5 Gy. 0.5 Gy irradiation preceeding the alloxan administration significantly suppressed the increase in pancreatic ...
In this paper the structural and functional changes of gamma irradiated bovine hemoglobin are presented. Aqueous solutions/1%/of HbO_2 were irradiated in air with doses ranging from 1 to 4 Mrad. Isoelectric focusing indicated change of the charge of irradiated hemoglobin. The isoelectric point of hemoglobin was displaced towards more acid values with increasing doses, up from 1 Mrad. Fingerprint analysis and peptide column chromatography of irradiated hemoglobin demonstrated disturbances increasing with the dose. These changes were confirmed by amino acid analysis which showed that Cys, Met, Trp, His, Pro and Tyr residues were destroyed or modified following irradiation. At doses exceeding 1 Mrad the irradiated solutions of hemoglobin showed a decrease of heme-heme interaction and an increase of affinity for oxygen. Differences observed in oxygen-dissociation ...
The present work is to study effects of neutron irradiation on the structure of amorphous Pb_8_0 Si_2_0 and Pd_7_7_._5 Cu_6 Si_1_6_._5 alloys by using X-ray diffraction techniques. differential scanning calorimertry (DSC) and internal friction measurements. The irradiation will produce obvious changes in the pair correlation function g(r) and radial distribution function RDF (r). The increase of crystallization temperature (Tx) and enthalpy of two specimens were found by DSC measurements after irradiation. The results of internal friction measurement show that the internal friction of the irradiated Pd_8_0Si_2_0 alloy is higher than that of the unirradiated in the temperature range of Tirradiation are discussed in terms of the concepts of density fluctuation defects (p) and shear stress fluctuation defects (#iota#).
Food irradiation is the processing of food products by ionizing radiation in order, among other things, to control food borne pathogens, reduce microbial load and insect infestation, inhibit the germination of root crops, and extend the durable life of perishable products. Irradiation of dried food ingredients, particularly herbs and spices, has a great application potential, and has already been implemented in many countries. Spice irradiation is performed to increase the hygienic quality and used as decontamination processes instead of fumigation methods. European Community approves irradiation processing as an effective residue-free alternative. The present paper evaluates the effect of ionizing radiation on sensorial properties of cinnamon (Laurus cinnamomum) and nut meg (Myristica fragans). The samples have been irradiated in multipurpose irradiator of {sup ...
In the Institute for Atomic Energy, Rikkyo University, just after the TRIGA-2 research reactor of 100 kW has attained the criticality, the cylindrical box for neutron radiography (NR) irradiation was made in the attached pool, and the research on NR was started in 1961. Thereafter in 1985, the vertical irradiation pipe was installed in the reactor tank, and the experiment for collecting the basic data was begun. In 1986, based on the obtained data, the NR irradiation facility on full scale was installed in No. 2 tangential horizontal experimental hole. As the main NR irradiation facilities, the vertical neutron irradiation pipe, the use of which is stopped now, the NR facility using the horizontal experimental hole (RUR/N2), the irradiation facility and ancillary facilities such as beam shutter, beam catcher and hoist are described. As the main equipments for ...
In the fuel testing facilities of Japan Atomic Energy Research Institute, the post-irradiation test of practical fuel used in nuclear power stations was begun in December, 1979, and the soundness of practical fuel has been confirmed, and the valuable post-irradiation test data on the behavior of fuel have been acquired. Recently, the heightening of fuel burnup has been advanced, and also in fuel testing facilities, the development and preparation of the post-irradiation testing facility required for examining in detail high burnup fuel have been carried out. The course of the installation of the post-irradiation testing facility and the outline of the facility are reported. As the preparation of the post-irradiation testing facility for high burnup fuel, a hyperfine hardness tester that measures dynamic hardness, the measuring instrument for pellet thermal diffusion rate by laser ...
Researches on oil palm empty fruit bunch (EFB) fibers and thermoplastic composites have been carried out by many workers in the last decade. The main focus was to enhance the properties of the resultant composites in view of the incompatibility of the two components. Thus, efforts have been made to enhance their properties by using coupling agents, treating the fibers and modifying the matrices. In this study, the effects of electron beam (EB) irradiation and some reactive additives (RAs) on the mechanical properties of EFB-PP (polypropylene) composites were evaluated. Different modes of irradiation were investigated. Mono, di and tri functional of monomers of RAs were used. irradiating PP alone, compared to irradiating the EFB fibers or irradiating both components, gave optimum properties for EFB-PP composites. Further, improvements of the properties of the composites were achieved ...
In-reactor testing of bolt-loaded compact tension specimens was performed in 360 C water. New data confirms previous results that high irradiation levels reduce SCC resistance in Alloy X-750. Low boron heats show improved IASCC (irradiation-assisted stress corrosion cracking). Alloy 625 is resistant to IASCC. Microstructural, microchemical, and deformation studies were carried out. Irradiation of X-750 caused significant strengthening and ductility loss associated with formation of cavities and dislocation loops. High irradiation did not cause segregation in X-750. Irradiation of 625 resulted in formation of small dislocation loops and a fine body-centered-orthorhombic phase. The strengthening due to loops and precipitates was apparently offset in 625 by partial dissolution of #gamma# precipitates. Transmutation of boron to helium at grain boundaries, coupled with matrix ...
The research and development for the first year of the project are performed through specialization of researchers, information from aborad and international cooperation, securement of advanced nuclear technology, development and installation of test equipment, application of external man-power, establishment of advanced test techniques, and certified test method. 1. Absolute efficiency measurement examination technology development of gamma scanning system 2. Sample preparation technology development of SEM and EPMA for micro-structural observation and chemical composition analysis 3. Irradiated high burn-up nuclear fuel transportation and test for PWR 4. Development of hot cell examination techniques and equipment 5. Acquirement of KOLAS system. In addition to the project, the following activities are carried out as follows; - PIE of Hanaro fuel(KH99H-001) - PIE of U-Mo advanced nuclear fuel irradiated at Hanaro - PIE of Hi-MET advanced ...
Strain controlled fatigue experiments on the modified ferritic-martensitic 12% Cr-steel Manet have been performed during, after and without irradiation. Continuous push-pull cycling of the hollow fatigue specimens with a cycle ratio R=-1, an axial strain rate of 8.10{sup -4} s{sup -1} and total strain ranges {Delta}{epsilon}{sub t} between 0.42% and 1.0% has been applied in vacuum (5.10{sup -3} Pa) at T=250 C. For the irradiation, a 104 MeV {alpha}-particle beam was used. Compared to unirradiated specimens, in-beam specimens undergo irradiation hardening at an advanced fatigue/implantation stage. Post-irradiation specimens show significantly higher total stress amplitudes and reduced fatigue lives. TEM investigations of in-beam and post-irradiation specimens reveal helium bubbles with different diameters on internal surfaces and in the matrix. (orig.).
Radioactive particles as well as x irradiation from an external source has been used in the treatment of rheumatoid arthritis, osteoarthritis, and ankylosing spondylitis. In order to clarify effects of ionizing irradiation on synovial cells, radioactive gold ("1"9"8Au) and yttrium ("9"0Y) were added to fibroblast cultures derived from human synovial membranes. Other cultures were irradiated by a Picker x-ray machine. Fibroblast growth and hyaluronic acid production were measured. Radioactive gold and yttrium particles induced a significant increase of hyaluronic acid synthesis rate (pg/cell/day) and inhibited fibroblast growth. Fibroblasts continued to overproduce hyaluronic acid and to show growth inhibition 3 weeks after irradiation with radioactive gold. Hydrocortisone inhibited hyaluronic acid overproduction induced by radioactive gold. Overproduction of hyaluronic acid induced by the x-ray machine ...
Pressureless-sintered AlN and hot-pressed, pressureless-sintered and reaction-bonded SiC were neutron irradiated at temperatures between 100 and 785degC up to a fluence of 5.2 x 10"2"4 n/m"2. The hardness was increased by up to 51% in AlN and 84% in SiC. The hardness decreased after annealing at temperatures around the irradiation temperature. At the same temperatures, the macroscopic length, which was increased by irradiation, also began to decrease. The hardness and length were almost recovered after 1,200 #approx# 1,400degC annealing. Thus, hardening in irradiated AlN and SiC is controlled by the number of point defects, or, more precisely, by the strain caused by small point defect clusters which pin down dislocation movement. Dislocation loops were still observed in some samples after 1,400degC annealing while the hardness was almost recovered to that in the unirradiated state. Thus, the existence ...
The Fast Flux Test Facility (FFTF) reactor, which started operating in 1982, is a 400 MWt sodium-cooled fast neutron reactor located in Hanford, Washington State, and operated by Westinghouse Hanford Co. under contract with U.S. Department of Energy. The reactor has a wide variety of functions for irradiation tests and special tests, and its major purpose is the irradiation of fuel and material for liquid metal reactor, nuclear reactor and space reactor projects. The review first describes major technical specifications and current conditions of the FFTF reactor. Then the plan for irradiation testing is outlined focusing on general features, fuel pin/assembly irradiation tests, and absorber irradiation tests. Assemblies for special tests include the material open test assembly (MOTA), fuel open test assembly (FOTA), closed loop in-reactor assembly (CLIRA), and other special fuel ...
The Fast Flux Test Facility (FFTF) reactor, which started operating in 1982, is a 400 MWt sodium-cooled fast neutron reactor located in Hanford, Washington State, and operated by Westinghouse Hanford Co. under contract with U.S. Department of Energy. The reactor has a wide variety of functions for irradiation tests and special tests, and its major purpose is the irradiation of fuel and material for liquid metal reactor, nuclear reactor and space reactor projects. The review first describes major technical specifications and current conditions of the FFTF reactor. Then the plan for irradiation testing is outlined focusing on general features, fuel pin/assembly irradiation tests, and absorber irradiation tests. Assemblies for special tests include the material open test assembly (MOTA), fuel open test assembly (FOTA), closed loop in-reactor assembly (CLIRA), and other special fuel ...
This study was carried out to evaluate the biochemical and morphological effects of ionizing radiation on ovary. Immature mice (ICR, 3 week-old) were irradiated at a dose of LD{sub 80(30)} at KAERI. The ovaries were collected after 6 hours, 12 hours, 1 day, and 2 days post irradiation. To analyze the morphological changes, histological staining with hematoxylin-eosin, immuno- histochemical preparation using in situ 3'-end labeling was performed. DNA fragmentation analysis and flowcytometric evaluation of DNA extracted from whole ovary were performed. As a result of DNA fragmentation analysis, DNA fragments with 185, 370, and 555 base pairs were clearly shown at 6 hours post irradiation. The percentage of A{sub 0} cell cycle was significantly increased in the irradiated group than control. In situ 3'-end labeled follicles were increased at 6 hours post irradiation. ...
Most radiologists accept that modest doses of irradiation (4500-5000 rad/4 1/2-5 weeks) can control subclinical regional lymph node metastases from squamous cell carcinomas of the head and neck and adenocarcinomas of the breast. There have been few reports concerning elective irradiation of the ilioinguinal region. Between October 1964 and March 1980, 91 patients whose primary cancers placed the ilioinguinal lymph nodes at risk received elective irradiation at the University of Florida. Included are patients with cancers of the vulva, penis, urethra, anus and lower anal canal, and cervix or vaginal cancers that involved the distal one-third of the vagina. In 81 patients, both inguinal areas were clinically negative; in 10 patients, one inguinal area was positive and the other negative by clinical examination. The single significant complication was a bilateral femoral neck fracture. The inguinal areas of four patients ...
Structural variations in 39-MeV alpha-particle irradiated (Tsub(irr) = 60 deg C) polycrystalline molybdenum during post-irradiation annealing were studied by X-ray and TEM methods. Despite the high density of irradiation induced defects in the structure of the specimen X-ray measurements showed zero relative lattice parameter change after an irradiation dose of 1.1 x 10"-_2 dpa. However, during the annealing #delta#a/a was changed in the positive range, exhibiting two peaks - at 100 and 300 deg C - whereas the damage structure detected by TEM indicated no changes. Analysis of the results leads to the conclusion that in the range 100 to 250 deg C migration of isolated vacancies and their annihilation at interstitial clusters as well as possible formation of new vacancy clusters occur. The second peak on the #delta#a/a temperature dependence curve is related to the transformation (probably, thermal ...
Effects of cell concentrations on the survival and repopulation of haemopoietic stem cells after irradiation were studied in the long-term culture of mouse bone marrow cells in vitro. No difference was observed in the survival of the stem cells among cultures in which 0 - 10/sup 7/ cells were re-inoculated on the adherent cell colonies in the culture flask. Stem cells showed a significant proliferation within 1 week and the number of the stem cells exceeded the control in 3 weeks after irradiation in the cultures with less than 10/sup 6/ re-inoculated cells per flask. In contrast, there was a considerable delay in the onset of stem cell proliferation after irradiation in the culture with 10/sup 7/ cells per flask. Based on these results, a possibility that a stimulator of stem cell proliferation, released from irradiated stromal cells, is cancelled by an inhibitory factor produced by ...
The 9.50 GHz electron paramagnetic resonance (EPR) spectra of unirradiated and "6"0Co #gamma#-ray irradiated cardamom (Elettaria cardamomum L. Maton, Zingiberaceae), ginger ((Zingiber officinale Rosc., Zingiberaceae), and saffron (Crocus sativus L., Iridaceae) have been investigated at room temperature. All unirradiated spices presented a weak resonance line with g-factors around free-electron ones. After #gamma#-ray irradiation at an absorbed dose of up to 11.3 kGy, the presence of EPR spectra whose amplitude increase monotonously with the absorbed dose has been noticed with all spices. A 100 "oC isothermal annealing of 11.3 kGy irradiated samples has shown a differential reduction of amplitude of various components that compose initial spectra, but even after 3.6 h of thermal treatment, the remaining amplitude represents no less then 30% of the initial ones. The same peculiarities have been noticed after 83 days storage ...
The molar of guinea pigs was irradiated with /sup 60/Co-..gamma.. ray for daily observations of the manifestation of disturbed tooth formation by microradiography and the time registration by tetracycline-labelling. Irradiation first injured young blast cells of the dentin in the growth phase, dental pulp cells, and cells of the enamel. The portion composed of injured cells formed a depressed ''constriction'' from the dental pulp side toward the border between the enamel and dentin. The cells of the enamel injured by irradiation in the growth phase later formed a very thin irregular stroma. In contrast, cells in the differentiation or subsequent phase at the time of irradiation and cells probably having started to grow after irradiation proceeded with formation of a normal stroma and calcification. No uniform relation was obtained between the ...
A new small size gamma irradiator is being set up at Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Brazil, with a revolutionary design. The developed technology for this facility consists of continuous tote box transport system, comprising a single concrete vault, where the automated transport system of products inside and outside of the irradiator utilizes a rotating door, integrated with the shielding, avoiding the traditional maze configuration. Covering 76 m{sup 2} of floor area, the irradiator design is product overlap sources and the maximum capacity of Cobalt-60 wet sources is 37 PBq (1 MCi). The irradiator is being installed in a Governmental Institution and it will be used as a demonstration facility for manufacturers, who need an economic and logistic in-house irradiation system alternative. Also, it will be useful for supporting the local scientific ...
The wholesomeness of irradiated wheat was investigated in a series of experiments involving several species of animals and a small number of children, at the National Institute of Nutrition in India. Our observations indicated some effects following the feeding of freshly irradiated wheat while no such changes were found in the groups fed either unirradiated or stored irradiated wheat. Also, there were no significant differences between the groups fed unirradiated and stored irradiated wheat. Based on these results, a recommendation had been made to the government that when subjected to irradiation, wheat should be stored for at least 3 months before considering it as safe for human consumption. Similar experiments conducted in an establishment of the Department of Atomic Energy in India indicated no undesirable effects, unlike those found in our studies, and this had led to the ...
A study was made into microstructure and hardening in austenitic stainless steel 0Kh18N10T irradiated with neon ions (230 MeV) and neutrons (E_n > 0.1 MeV). The experiments were accomplished using an external beam of U-400 cyclotron (Dubna) and EWA reactor (Poland). The dependences of tensile properties, hardening index, microstructure, dislocation density on damaging dose were determined. An attempt is made to reveal the correlation between an yield strength increment and defect cluster accumulation. The interpretation of variations of mechanical properties and microstructure under irradiation is given.
In order to study the effects of microwaves on chemical reactions equipment was designed to acquire in-situ vibrational spectra of sol-gel components as they are irradiated with microwaves. Fourier Transform Infrared (FTIR) and Raman spectroscopy were used. A low temperature (10K) FTIR cell was used to trap samples in an argon matrix at 10{sup -7} Torr. For the liquid samples no differences were seen in spectra of irradiated and nonirradiated samples, but the argon matrix isolation technique showed dramatic differences.
Thermal analysis testing revealed slight weight changes, which were a function of gamma irradiation, in a highly reduced Defense Waste Processing Facility (DWPF) simulated waste glass. Transmission electron microscopy (TEM) was performed on this glass to determine if the weight change corresponded to microstructural variations. TEM analyses showed that no microstructural changes were attributable to gamma irradiation. Exposure of the samples to the electron beam in the TEM did cause changes in the glass microstructures in some cases. These changes were likely due to localized heating of the glass due to interactions with the transmitted electrons.
It may result in acute radiation syndrome after body is exposed to ionizing radiation. The one of long-term effects of irradiation injury is leukemia. The bone marrow cells (BMC) transplantation including stem cells is the only effective therapy for acute radiation syndrome patients. Recently, with the advancement of stem cell research that the stem cells have multipotential and can convert each other, it may supply the new stem source for the irradiation injury patients. At the same time with the further research of radioprotective reagents, the hematopoietic stem cells proliferation after irradiation injury is promoted
The behavior of the superconducting transition temperature T/sub c/ of single-crystal and polycrystalline V_3Si was investigated as a function of low-fluence neutron irradiation. It is found that the initial degradation of T/sub c/ is sample-dependent, some specimens showing no degradation in T/sub c/ up to a fluence of 2 x 10"1"8 n/cm"2. This and many other earlier observations on low-fluence behavior are explained in terms of a recently proposed model of radiation damage in A-15 compounds.
A survey is presented of the consequences of the irradiation of the population with ionizing radiation. There is an increased incidence of leukemia in irradiated population groups. Among the inhabitants of Hiroshima and Nagasaki maximum death of leukemia was observed in the years 1951 to 1952. The results are summed up of the observation of carcinoma of the breast, lungs and bronchi, bones, and carcinoma of the thyroid. The effect of radiation on experimental animals is described. It was found that the scatter of the dependence of the incidence of various types of cancer on the dose equivalent apparently reflects differences in the biological mechanism of this incidence and that a proportional relationship cannot be expected between the primary damage of cells during irradiation and the actual manifestation of the disease. (E.S.).
The short range of low-energy electrons has made them suitable for the treatment of skin lesions, especially when extensive areas must be irradiated with special considerations to save the normal underlying tissue. This report covers some salient features of total body electron irradiation: the construction of the large fields required, x-ray contamination levels, and multiple-field techniques. While the investigation is essentially experimental, we also indicate the results of calculations. We conclude most generally that treatment planning with whole skin irradiations can be as precise as with smaller fields.
A simple highly efficient procedure has been developed for recovery of thallium radioisotopes from lead and bismuth targets irradiated by 1-GeV protons. The procedure is based on the use of extraction chromatography. The cross-sections have been determined for formation of {sup 200}Pb, {sup 201}Pb, {sup 202m}Pb, and {sup 203}Pb radioisotopes in targets from lead with natural isotopic composition, irradiated by 1-GeV protons.
A simple highly efficient procedure has been developed for recovery of thallium radioisotopes from lead and bismuth targets irradiated by 1-GeV protons. The procedure is based on the use of extraction chromatography. The cross-sections have been determined for formation of "2"0"0Pb, "2"0"1Pb, "2"0"2"mPb, and "2"0"3Pb radioisotopes in targets from lead with natural isotopic composition, irradiated by 1-GeV protons.
Current information on the use of ionizing radiation for improving the storage of subtropical fruits like citrus, grapes, and avocados is reviewed. The feasibility of applying radiation either alone or in combination with other physical or chemical treatments for the control of postharvest fungal diseases is considered. Irradiation effects on the physiology of the fruits as related to respiration, ethylene evolution, changes in major chemical constituents, and quality are discussed. The recent trends in the possible use of irradiation as an alternative treatment to chemical fumigants for disinfestation of citrus and avocados and the prospects for the future application of irradiation for preservation of some of these fruits are outlined. 128 references.
A study was made on the effect of 3.5 MeV electron irradiation on the properties of light-emissive structure based on GaAlAs. It is shown that a considerable decrease in the emitted light intensity as a result of electron irradiation not accompanied by changes in recombination- and electric properties of the mentioned structures. It is established by the electron-microscopy and Auger-spectroscopy meazurements that electron irradiation causes the occurrence of regions of free aluminium clusters on the external surface of the structure n-layer. The number and the sizes of the regions depend on the electron doze. It was assumed that the mentioned regions can play a role of attenuation filter for the light emitted by the structure.
Methylmethacrylate polymerisation in the presence of 4 wt% butadiene-acrylonitrile rubber was carried out at fixed dose-rate and temperature. The effect of irradiation was investigated with respect to the mechanical and dynamic-mechanical properties in the solid state. A general increase of the 'compatibilisation' on irradiation is obtained. In fact both rubber and polymethylmethacrylate glass transition temperatures, determined through dynamic-mechanical analysis, reveal the presence of strong interactions between the components. Furthermore an improvement of the mechanical tensile properties of the blends is observed when irradiation is continued after polymerisation, at least until a certain absorbed dose.
Single photon emission computed tomography (SPECT) of lung perfusions permits to map functioning lung parenchyma with higher sensitivity than CT. Delivering higher radiations doses it used to increase local control in lung carcinoma; this strategy is based on radiobiological and clinical studies. Lung parenchyma is a dose-limiting tissue in patients irradiated for lung cancer. Functional mapping based on SPECT and CT findings permits to design radiation beams such as to minimize irradiation of functioning lung.
The effects on reproductive functions of feeding adult rhesus monkeys on a diet of irradiated wheat flour and potato was investigated. Wheat flour and potatoes were exposed to 75 000 and 10 000 rad, respectively, of #gamma#-irradiation and then fed to the animals. Various parameters of reproductive function were compared with those of animals fed on unirradiated food. These were: external changes in the reproductive organs, menstrual cycle, vaginal cytology, assay of urinary hormones (oestrogens and pregnanediol), and post-mortem histopathological examination of the reproductive organs. At the end of 3 months, the experimental and control animals behaved similarly with regard to their reproductive functions. (author).
Purpose : To evaluate whether the early pulmonary irradiation can prevent or decrease the pulmonary damage and contribute to improve ultimate survival in paraquat lung. Materials and Methods : From Jun. 1987 to Aug. 1993, thirty patients with paraquat poisoning were evaluated. Fourteen of these patients were received pulmonary irradiation(RT). All of the patients ere managed with aggressive supportive treatment such as gastric lavage, forced diuresis, antioxidant agents and antifibrosis agents. Ingested amounts of paraquat were estimated into three groups(A: minimal < about 5cc, B: mouthful 5-50 cc, C: Large > 50cc). Pulmonary irradiation was started within 24 hours after admission(from day 1 to day 11 after ingestion of paraquat). Both whole lungs were irradiated with AP/PA parallel opposing fields using C0-60 teletherapy machine. A total of 10Gy(2Gy/fr. X 5 days)was delivered without ...
Our institute has been investigating laser-produced tin, lithium and xenon plasma for extreme ultraviolet (EUV) light source of EUV lithography system, and found the highest conversion efficiency of 3% at 13.5 nm in 2% bandwidth. In the present paper, we introduce fabrication methods of density-controlled tin targets to generate relatively monochromatic EUV, and higher conversion efficiency than bulk tin. The first method is the nano-template method, where liquid tin solution was immersed into a polymer film with monodispersed size nano-particle. The density can be controlled by tin concentration of the solution. The target can be classified into mass-limited target. We have shown a tendency of monochromatic EUV emission around 13.5 nm with decreasing of tin density. The intensity was higher than tin foil with bulk density. The tendency has a merit to mitigate heat effect of the first EUV mirror. The fabrication method has another merit to control not only density ...
Our institute has been investigating laser-produced tin, lithium and xenon plasma for extreme ultraviolet (EUV) light source of EUV lithography system, and found the highest conversion efficiency of 3% at 13.5 nm in 2% bandwidth. In the present paper, we introduce fabrication methods of density-controlled tin targets to generate relatively monochromatic EUV, and higher conversion efficiency than bulk tin. The first method is the nano-template method, where liquid tin solution was immersed into a polymer film with monodispersed size nano-particle. The density can be controlled by tin concentration of the solution. The target can be classified into mass-limited target. We have shown a tendency of monochromatic EUV emission around 13.5 nm with decreasing of tin density. The intensity was higher than tin foil with bulk density. The tendency has a merit to mitigate heat effect of the first EUV mirror. The fabrication method has another merit to control not only density ...
In order to follow some of the changes induced by ultraviolet-B (UV-B, 280-320 nm) radiation in Phaseolus vulgaris and Brassica napus, experiments were designed to localize sites of changes in leaves and to correlate some of the physiological and biochemical changes with penetration of UV-B radiation. B.napus was exposed to 8.9 kJ m"-"2 day"-"1 biologically effective UV-B radiation (UV-B_B_E). The penetration of UV-B radiation into the leaf was followed using a quartz fibre optic microprobe. Monochromatic radiation at 310 nm was decreased by ca 50 and 34% in the adaxial and abaxial epidermis, respectively, in plants not exposed to UV-B, whereas the radiation was decreased by ca 70 and 42%, respectively, in the same region in UV-treated plants. Polychromatic radiation showed a wavelength dependent change mainly for the collimated radiation. The results correlated with the distribution of phenolic compounds analysed from 40 #mu#m paradermal leaf sections. The first ...
We describe the growth, fabrication, and characterization of an ultraviolet (UV) photoconductive detector based on In{sub x}Al{sub y}Ga{sub 1-x-y}N quaternary alloy that is lattice matched to GaN. The detector consisted of 0.1 {mu}m In{sub x}Al{sub y}Ga{sub 1-x-y}N alloy grown on 0.5-1.0 {mu}m GaN epilayer by metalorganic chemical vapor deposition. With varying indium concentration, the cut-off wavelength of the In{sub x}Al{sub y}Ga{sub 1-x-y}N detectors could be varied to the deep UV range. The most important and intriguing result is that the responsivity of the In{sub x}Al{sub y}Ga{sub 1-x-y}N quaternary alloy exceeded that of AlGaN alloy of a comparable cutoff wavelength by a factor of five. This makes the nitride quaternary alloy very important material for solar blind UV detectors applications particularly in the deep UV range where Al rich AlGaN alloys have problems with low quantum efficiency and cracks due in part to lattice mismatch with GaN. The ...
We describe the growth, fabrication, and characterization of an ultraviolet (UV) photoconductive detector based on In_xAl_yGa_1_-_x_-_yN quaternary alloy that is lattice matched to GaN. The detector consisted of 0.1 #mu#m In_xAl_yGa_1_-_x_-_yN alloy grown on 0.5-1.0 #mu#m GaN epilayer by metalorganic chemical vapor deposition. With varying indium concentration, the cut-off wavelength of the In_xAl_yGa_1_-_x_-_yN detectors could be varied to the deep UV range. The most important and intriguing result is that the responsivity of the In_xAl_yGa_1_-_x_-_yN quaternary alloy exceeded that of AlGaN alloy of a comparable cutoff wavelength by a factor of five. This makes the nitride quaternary alloy very important material for solar blind UV detectors applications particularly in the deep UV range where Al rich AlGaN alloys have problems with low quantum efficiency and cracks due in part to lattice mismatch with GaN. The advantages of In_xAl_yGa_1_-_x_-_yN quaternary over ...
The US National Aeronautics and Space Administration (NASA) has been monitoring the ozone layer from space using optical remote sensing techniques since 1970. With concern over catalytic destruction of ozone (mid-1970s) and the development of the Antarctic ozone hole (mid-1980s), long term ozone monitoring has become the primary focus of NASA's series of ozone measuring instruments. A series of TOMS (Total Ozone Mapping Spectrometer) and SBUV (Solar Backscatter Ultraviolet) instruments has produced a nearly continuous record of global ozone from 1979 to the present. These instruments infer ozone by measuring sunlight backscattered from the atmosphere in the ultraviolet through differential absorption. These measurements have documented a 15 Dobson Unit drop in global average ozone since 1980, and the declines in ozone in the antarctic each October have been far more dramatic. Instruments that measure the ozone vertical distribution, the SBUV ...
We report on the ultraviolet laser absorption spectroscopy of atomic Gd at 394-554 nm where two transition lines are place very closely by using a frequency-doubled beam of external-cavity diode laser (ECDL). One is from 999.121 to 26337.071 cm-1 and the other from 0 to 25337.755 cm-1. If two transition lines are placed closely within a continuous fine tuning range, the real-time measurement of the atomic excitation temperature is possible without any significant time consumption because at least two transition lines originating from different low-lying energy levels need to be investigated for the Boltzmann-plot. Since the spectral difference between the two transitions is only about 0.195 cm-1 (5.85 GHz), it is possible to record both the absorption spectra simultaneously as shown in Fig. 1. But the transition probabilities (or oscillator strengths) of these lines have not been measured accurately yet to the best of our knowledge. We report on the newly measured ...
The Westinghouse Electric Corporation has undertaken to investigate, develop, and characterize laser-assisted processing techniques utilized to produce the fine line, thin metal grid structures that are required to fabricate high-efficiency solar cells. Two basic techniques for metal deposition will be investigated, as follows: (1) photochemical decomposition of liquid or gas phase organometallic compounds utilizing either a focused, CW ultraviolet laser (System 1) or a mask and ultraviolet flood illumination, such as that provided by a repetitively pulsed, defocused excimer laser (System 2), for pattern definition, and (2) thermal deposition of metals from organometallic solutions or vapors utilizing a focused, CW laser beam as a local heat source to draw the metallization pattern. The purpose of this contract is to investigate the various existing laser-assisted film deposition techniques in order to develop a new, cost-effective technology ...
Glycosaminoglycan synthesis was studied in cell populations of ultraviolet light-induced murine cutaneous fibrosarcoma cells under conditions of varying growth rates in vitro. After labeling with the precursors, /sup 3/H-glucosamine and /sup 35/SO/sub 4/, sulfated glycosaminoglycans recoverable by direct proteolysis of the culture monolayers increased approximately 5-fold on a per cell basis from sparsely populated, exponential cell cultures (greater than 85% of cells in S, G2, or M phases) to stationary cultures inhibited by high cell density (greater than 50% of cells in G1). Within this cell surface-associated material, the relative ratio of heparan sulfate to the chondroitin sulfates was approximately 60/40% under conditions of exponential growth; in the growth-arrested cultures, the reverse ratio was found. The substratum attached material, obtained from the flask surface after ethyl glycol bis(beta-aminoethyl ether)-N,N'-tetraacetic acid ...
Benzene molecules , present in the proto-planetary nebula CRL 618, are ionized and dissociated by ultraviolet (UV) and X-ray photons originated from the hot central star and by its fast wind. Ionic species and free radicals produced by these processes can lead to the formation of new organic molecules. The aim of this work is to study the photoionization and photodissociation processes of the benzene molecule, using synchrotron radiation and time-of-flight mass spectrometry. Mass spectra were recorded at different energies corresponding to the vacuum UV (21.21 eV) and soft X-ray (282-310 eV) spectral regions. The production of ions from the benzene dissociative photoionization is here quantified, indicating that C_6H_6 is more efficiently fragmented by soft X-ray than UV radiation, where 50% of the ionized benzene molecules survive to UV dissociation while only about 4% resist to C-rays. Partial ion yields of H and small hydrocarbons, such as C_2H_2"+, C_3H_3"+, ...
Titanium base 'alpha'-alloys (Pt-7M, RK-20 and Ti-5Al-2Zr-1.5V) are considered for their behaviour under neutron irradiation. The role of alloying elements in radiation hardening is discussed depending of neutron fluence and irradiation temperature. For PK-20 alloy three stages of change in mechanical properties are revealed which are following: incubation period and weak hardening, intense radiation hardening, radiation hardening attenuation. Irradiation temperature rise results in an increase of incubation period and threshold neutron fluence. A special attention is paid to hydrogen absorption in #alpha#-titanium alloys under irradiation. It is concluded that titanium base 'alpha'-alloys are serviceable as structural materials in nuclear plants with allowance made for peculiar features of their radiation behaviour. 4 refs.; 7 figs.; 1 tab.
Weld metal, base material and stainless steel overlay specimens for Charpy tests and static tensile tests were irradiated for a year in a power reactor of the Bohunice nuclear power plant in place of the evaluated surveillance specimens. The material of the specimens was identical with that of the WWER-440 reactor pressure vessels, and was exposed to a fluence of (1.2 - 4.5) x 10"2"3 m"-"2 (E > 0.5 MeV) at approximately 270 degC. Some of the irradiated as well as unirradiated specimens were subjected to regeneration annealing at 475 degC for 168 h. The behavior of the materials after irradiation and annealing was evaluated. (author). 33 tabs., 32 figs., 8 refs.
Presented are the investigation results of electrophysical and physico-mechanical properties of KLF-20, Viksint U-4-21, Viksint KT-73, UF-7-21, KG-184, KL-4, KL-16SE-305, VIAT-1 and PPK-21 sealants, irradiated with sources of continuous and pulse #gamma#-radiation, as well as pulse #gamma#-neutron radiation. It is shown that electrophysical and physico-mechanical properties of sealants after irradiation by continuous #gamma#-radiation up to 10"6 doses and pulse gamma-neutron radiation with neutron fluence of 10"1"3 neutron/cm"2 and #gamma#-radiation dose of 10"4R do not practically change. Electric conductivity and tangent of the angle of dielectric losses increase in the process of irradiation. Electric conductivity depends on irradiation type, is proportional to dose rate and does not depend on temperature and pulse duration.
The aim of this study is to evaluate the specificities of the irradiation of drugs in frozen aqueous solution. The structures of the degradation products were determined to gain insight into the radiolysis mechanisms occurring in frozen aqueous solutions. Metoclopramide hydrochloride and metoprolol tartrate were chosen as models. The frozen solutions were irradiated at dry ice temperature by high energy electrons at various doses. The drug purity (chemical potency) and the radiolysis products were quantified by HPLC-DAD. Characterization of the degradation products was performed by LC-APCI-MS-MS. The structures of the radiolysis products detected in irradiated frozen aqueous solutions were compared to those detected in solid-state and aqueous solutions (previous studies). For both metoclop...
The Monte-Carlo method and experimental methods were used to determine the neutron fluxes in the irradiation channels of the Ghana Research Reactor -1. The MCNP5 code was used for this purpose to simulate the radial and axial distribution of the neutron fluxes within all the ten irradiation channels. The results obtained were compared with the experimental results. After the MCNP simulation and experimental procedure, it was observed that axially, the fluxes rise to a peak before falling and then finally leveling out. Axially and radially, it was also observed that the fluxes in the centre of the channels were lower than on the sides. Radially, the fluxes dip in the centre while it increases steadily towards the sides of the channels. The results have shown that there are flux variations within the irradiation channels both axially and radially. (au)
Simulation irradiation experiments were carried out to investigate the formation processes and contribution to hardening of radiation-induced features in low alloy steels. Medium Cu (0.12 and 0.16%) and low Cu (0.03%) A533B steels were irradiated with 3 MeV Ni ions and 5 MeV electrons, and in KUR at 290degC. Irradiated steels were examined by three-dimensional atom probe, positron annihilation, high-resolution transmission electron microscopy and hardness measurements. Electron irradiation caused almost the same hardening as KUR irradiation in medium Cu steels under almost the same dose rate and dose conditions, whereas the formation of larger, denser and more Cu enriched clusters and smaller accumulation of single vacancies were confirmed for KUR irradiation. This indicated that cascade damage provides additional cluster nucleation sites to compensate for lower ...