Y-ray Irradiation Research Articles

γ-Ray Irradiation Enables Annealing- and Light-Soaking-Free Solution Processable SnO2 Electron Transport Layer for Inverted Organic Solar Cells.

The electrode buffer layer is crucial for high-performance and stable OSCs, optimizing charge transport and energy level alignment at the interface between the polymer active layer and electrode. Recently, SnO2 has emerged as a promising material for the cathode buffer layer due to its desirable properties, such as high electron mobility, transparency, and stability. Typically, SnO2 nanoparticle layers require a postannealing treatment above 150°C in an air environment to remove the surfactant ligands and obtain high-quality thin films. However, this poses challenges for flexible electronics as flexible substrates can't tolerate temperatures exceeding 100°C. This study presents solution-processable and annealing-free SnO2 nanoparticles by employing y-ray irradiation to disrupt the bonding between surfactant ligands and SnO2 nanoparticles. The SnO2 layer treated with y-ray irradiation is used as an electron transport layer in OSCs based on PTB7-Th:IEICO-4F. Compared to the conventional SnO2 nanoparticles that required high-temperature annealing, the y-SnO2 nanoparticle-based devices exhibit an 11% comparable efficiency without postannealing at a high temperature. Additionally, y-ray treatment has been observed to eliminate the light-soaking effect of SnO2. By eliminating the high-temperature postannealing and light-soaking effect, y-SnO2 nanoparticles offer a promising, cost-effective solution for future flexible solar cells fabricated using roll-to-roll mass processing.

Evaluation of the Effects of Irradiation of Peanut Grain by a Gamma-Ray Beam on Culture

The problems of agriculture in Senegal result in a low yield per hectare and poor seed quality contributing strongly to the decline in productivity. Mutagenesis by X- or Y-ray irradiation makes it possible to obtain genetic mutants necessary to improve production. It is in this context that we undertook this study to evaluate the effects induced on the cultivation of peanut seeds irradiated by X-rays at low doses applied in radiotherapy. X-ray irradiation of four (2, 3, 4, 5) lots of peanuts are performed with respectively 0.5, 1.5, 2 and 4 Gray using the cobalt 60 therapy device (Alcyon II). The seeding of the seeds and then the following-up of the crops during 35 days allowed us to study the parameters of germination, growth and yield. The results obtained after monitoring revealed that the irradiation did not have any significant impact on germination and would appear to temporarily inhibit the growth rate compared to the control batch. However, the decrease in weight of the harvested seeds can be explained by the absence of fertilizer during the cultivation.

Alpha-Particles and 60Co y-Rays Have Different Biological Effects on Upland Cotton (Gossypium hirsutum L.) Pollen Grains

To compared the irradiation effects by y-rays and alpha-particles on the structure and function of upland cotton pollen grains during pollination, pollen grains from Gossypium hirsutum L. cultivar “Lumian 21” were irradiated by alpha-particles (1, 10, 30, 40 and 100 Gy) and y-rays (20, 30 and 40 Gy). We looked for changes in the ultrastructure of the exine and interior walls of the pollen grains. After germinating the irradiated pollen grains in liquid medium, we looked for changes in germination rate, the number of pollen tubes in styles after pollination and F-actin distribution in the pollen tubes. Alpha-particles penetrated and etched the exine and interior walls of the pollen grains and also damaged the organelles in the pollen grains. More pollen grains were destroyed as the alpha-particles dose increased. y-rays had no effects on the exine walls of the pollen grains but had stronger effects on the interior structure of the pollen grains than those induced by alpha-particle irradiation. The pollen grain germination rate, the number of pollen tubes in the styles and the average length of the pollen tubes in pollen grains treated with y-ray irradiation were decreased and shortened with increased y-rays irradiation dose, compared with that of control. However, under alpha-particle irradiation, these features initially increased at a low level of irradiation (1 Gy) and then decreased as the dose was increased. There was evident damage to F-actin structures in pollen tubes induced by the two kinds of mutagens. The mechanisms underlying the biological effects induced by alpha-particles and y-rays were different. The function and structure of pollen tubes in pollination and fertilization may be affected by the ultrastructure of pollen grains.

Factors Affecting the Solid-State Polymerization of 1,4-Bis(1,3-octadecadiynyl)benzene to a Polydiacetylene

In an attempt to produce a polydiacetylene (PDA) with larger third order nonlinear optical properties, the polymer precursor, 1,4-bis(1,3-octadecadiynyl)benzene, was synthesized. It was found, however, that neither thermal treatment (up to 343 K) nor γ-ray irradiation at above 300 K was able to promote solid-state polymerization. A detailed analysis of the molecular motion was conducted using differential scanning calorimetry, solid-state cross-polarization magic-angle-spinning 13 C, and solid-state 2 H NMR and solution-state 13 C NMR. It was found that below 300 K the monomer undergoes small-amplitude motions only. Above 300 K the sp-bonded phenyl ring undergoes π flips around the long axis of the molecule at an intermediate rate with respect to the NMR time scale (<2 x 10 -5 Hz -1 ) with an activation energy of 60 ± 1 kJ mol -1 . The poor polymerization above 300 K was attributed to the monomers being unable to obtain the proper alignment with respect to each other necessary for the polymerization process. The results of this study lead to the successful polymerization of the monomer by using y-ray irradiation but at 273 K. The structure of the polymer was determined using solid-state 13 C NMR.

Cloning of the rat Gadd45 cDNA and its mRNA expression in the brain

We cloned the rat Gadd45 (growth arrest and DNA damage inducible) cDNA and examined its mRNA induction by y-ray irradiation in the rat brain. The rat Gadd45 cDNA sequence was highly homologous to the previously published human and hamster cDNAs, and was partially similar to the 28S rRNA gene. The mRNA encoding rat GADD45 was induced in the brain after γ-ray irradiation. This finding indicates that Gadd45 is an inducible gene following the ionizing radiation, not only in cultured cells in vitro, but also in animal tissues in vivo.

Growth of Lactococcus lactis subsp lactis in reconstituted irradiated milk powder

Summary - Low heat milk powder was submitted to y-ray irradiation in order to sterilize it and then tested for grawth of L lactis subsp lactis strains CNRZ 1076 (prtt) and its non-proteolytic-variant, CNRZ 1075 (prt-). Inhibition was observed when reconstituted milk was inoculated at a level of 104 but not 106 cfu/ml. This inhibition was partly relieved by addition of superoxide dismutase (SOD) suggesting a correlation with the production of 02-' The maximum stationary phase populations of CNRZ 1076 (prtt) in reconstituted milk from irradiated powder and in reference milk were identical while the maximum stationary phase population of CNRZ 1075 (prt-) was significantly higher in reconstituted milk made from irradiated powder. Amino acids analysis of the non-protein fraction revealed that irradiation led to a release of peptides, which Iikely enhanced final yields of prt-. Consequently, irradiated milk acidification by L lactis CNRZ 1076 (prt-) was delayed, while that of CNRZ 1075 (prt-) was greatly stimulated.

Radiation-induced effects on alternative fuels

After the so-called energy crisis occurred in the 70's 1 several macromolecules have been investigated as alternative energy and chemical feed stocks. Among several possibilities coal has received special attention due to its large proven reserves as well as the similarity between the products obtained by its processing and crude oil. 2-5 One of the constituents present in crude oil and coal-derived products is composed of brown solids, brittle, without a well-defined melting point named asphaltenes. 6 They are isolated from liquid fuels by precipitating the benzene-soluble material with hydrocarbons such as pentane or hexane. 7 In previous publications we have studied the effects of X-ray irradiation on solvent refined coal, 8 asphaltenes 9 and asphaltols. 1~ Using a proper analytical method based on liquid chromatography, developed in our laboratory, ix the irradiation products were studied. As a generall rule it was found that X-ray irradiation can promote decomposition of the macromolecules investigated thus producing lower molecular weight products including hydrocarbons. 8-I~ In the present work the chemical effects of y-ray irradiation of asphaltenes produced from coal are reported.

Oxygen-transport and solution properties of polylipid/Hb vesicles (ARC).

Polymerized phospholipid vesicle encapsulating Hb (polylipid/Hb vesicle) was prepared from a mixture of unsaturated phospholipid, cholesterol and unsaturated fatty acid and polymerization by gamma-ray irradiation. The average radius of resulting vesicles was 203 +/- 39 nm and concentrated Hb (30 wt%) was efficiently encapsulated. gamma-Ray polymerization proceeds theoretically at low temperature (4 degrees C). P50 and oxygen transporting efficiency were adjusted to 40 mmHg and 40%, respectively. Oncotic pressure and solution viscosity can be controlled to the same values as blood.

Changes in cochlear microphonic response after Y-ray irradiation of the inner ear of the guinea-pig.

The effects of ionizing irradiation on the cochlear microphonic response of guinea-pigs were studied. The cochlear microphonics (CM) of both ears were recorded in a total of 36 animals. Recording was carried out by the differential electrode technique on the basal turn of the cochlea. One week prior to recording, the left ear of each animal had been exposed to 35-70 Gy radiation in increments of 5 Gy. Doses of 40 Gy and above led to a reduction in CM response. After doses of 60 Gy or more, no CM response could be detected. Damage most probably occurred in the outer and inner hair cells.

Effect of Irradiation and Immobilization on Spinach Chloroplast Activities

Abstract The effect of y-ray irradiation and immobilization by means of radiation polymerization on PS II activity (O2 evolution) of isolated chloroplasts from spinach was investigated. Reduction of O2 evolution activity by irradiation was small at lower temperatures below – 24 °C, but the activity decreased slightly by freezing at extremely low temperature below –78 °C. So the optimum low temperature range for the treatment was observed. The immobilized chloroplast in a hydrophilic polymer matrix showed the stable duration of O2 evolution activity more than 700 h at 4 °C . Thermo-stability of chloroplast was also improved greatly by immobilization. The active center of PS II in immobilized chloroplasts was retained even after 60 min standing at 50 °C.

Formation of hydrated electrons upon dissolution of crystals containingF centres

The hydrated electron (symbol e~q) joined definitively itself to the family of chemical reagents during the last decade. Its discovery will be remembered without any doubt among the most brilliant results achieved in the chemical field ia these years. The hydrated electron is formed by an electron surrounded by four oriented molecules of water, in other words c~ is an electron trapped in a cage of water molecules. I ts fundamental chemical characteristic is an unusually high electron donor capacity which makes its reactivity very high and therefore its mean life very short in all media. Hydrated electrons can be produced in several manners (1), for instance by metal dissolution in water, by electrochemical reduction, by photolysis, etc., but the principal method for producing e~Q is the radiolysis of water solutions. Indeed the most important contributions to the discovery and chemical characterization of hydrated electron came and are coming from the radiation chemistry, particularly from pulsed radiolysis. Sometimes the individuation of the chemical reactivity of e~ towards certain substances is made difficult by the fact that many other radicals are produced together with e~q by radiolysis. Therefore a method capable to produce only, or almost only, e~q without any serious chemical complications, as for instance those connected with the method of alkali-metal dissolution in water, should be interesting. The dissolution in water of crystals containing E centres seemed to us a potential source of hydrated electrons having the properties mentioned above. I t is well known that an _~ centre results when an electron is trapped at the site of a missing anion. When crystals conta in ing/~ centres are dissolved in water the cation cage which traps the electron is destroyed and the electron should be freed into the solution giving rise to e~. As the concentration of F centres in alkali halides can at tain values as high as 101 F centres/em 3 (that is 5.1017 _F centres/g) and the solubility for instance of NaC1 in water is ~ 330 g/l, the potential amount of e:~ which can be generated upon crystal dissolution reaches values of the order of a few 10-dg equiv/l. The F centres in alkali halides can be produced by Xor y-ray irradiation or by incorporating an excess of alkali metal in the crystal. The alkali excess occupies normal

Chromosome Aberrations in Peripheral Blood Cells in Man Following Chronic Irradiation from Internal Deposits of Thorotrast

The in vivo production of chromosome aberrations in the peripheral leukocytes of individuals subjected to X-ray, y-ray, and neutron irradiation has been demonstrated by several investigators. To date, such observations have been reported in the cases of persons X-rayed for diagnostic reasons (1-4), personnel subjected to occupational exposure (5, 6), patients therapeutically irradiated (7-11), and individuals accidently exposed to radiation (6, 12, 13). In contrast to these observations on the effects of acute external irradiation, the present study concerns a group of patients who have been subjected to chronic internal irradiation over the course of many years. The radiation in these cases is derived from isotopes of the Th232 decay series, administered in the form of Thorotrast-a commercial preparation of thorium dioxide which was introduced as a contrast medium for radiography in 1931. Because of its ease of administration and its excellent contrast properties, it was widely used for several years in arteriography, and to a lesser extent for other applications such as retrograde pyelography. It came into disrepute, however, around 1945 after warnings of its possible toxic effects had appeared in the literature, and its use as a contrast medium in routine radiography has since been largely discontinued.

The Influence of Oxygen and Water on the After-Effect in Cellulose Degradation by Gamma-Rays

It was shown in this laboratory (1, 2) that when wood cellulose with a low moisture content (0.26 %) was irradiated in air with y-rays and stored in vials, there was a progressive decrease in its viscosity in cupriethylenediamine up to 30 days after the first measurement. This decrease was referred to as an after-effect, as opposed to the primary effect which is the difference between the viscosity of the control (unirradiated) sample and that of the irradiated sample measured as soon as possible after the end of irradiation. When these low-moisture samples were irradiated, then wetted with excess water or freely exposed to air, the after-effect was curtailed (2). Samples irradiated at higher moisture levels (3.3 % to 5.6 %) showed no after-effect. It was concluded that the curtailment or prevention of the after-effect may be due to either water or oxygen. The present investigation was undertaken to determine the influence of water and oxygen on the after-effect in the -y-ray irradiation of cellulose.