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1
Mojtahedi, F., A. Pooladi, F. Sirati, E. Kaihani, Sh Akhlaghpour, M. Karimlou, I. Bagherizadeh, M. Fallah, S. Ghasemi Firouzabadi e F. Behjati. "Abberant Lymphocytes Rate after Gamma-Irradiationn as a Biomarker of Breast Cancer". Sarem Journal of Reproductive Medicine 1, n. 3 (1 luglio 2016): 89–95. http://dx.doi.org/10.29252/sjrm.1.3.89.
2
Yin, B., e A. Forer. "Coordinated movements between autosomal half-bivalents in crane-fly spermatocytes: evidence that ‘stop’ signals are sent between partner half-bivalents". Journal of Cell Science 109, n. 1 (1 gennaio 1996): 155–63. http://dx.doi.org/10.1242/jcs.109.1.155.
Abstract (sommario):
During anaphase-I in crane-fly spermatocytes, sister half-bivalents separate and move to opposite poles. When we irradiate a kinetochore spindle fibre with an ultraviolet microbeam, the associated half-bivalent temporarily stops moving and so does the partner half-bivalent with which it was paired during metaphase. To test whether a ‘signal’ is transmitted between partner half-bivalents we irradiated the spindle twice, once in the interzone (the region between separating partner half-bivalents) and once in a kinetochore fibre. For both irradiations we used light of wavelength 290 microns and a dose that, after irradiating a spindle fibre only, altered movement in 63% of irradiations (12/19); in 11 of the 12 cells both partner half-bivalents stopped moving after the irradiation. In control experiments we irradiated the interzone only: these irradiations generally did not stop chromosomal poleward motion but sometimes (14/29) caused poleward movement to each pole to be abruptly reduced to about half the velocity prior to irradiation. In double irradiation experiments we varied the order of the irradiations. In some double irradiation experiments we irradiated the interzonal region first and the spindle fibre second; in 75% (9/12) of the cells the half-bivalent associated with the irradiated fibre stopped moving while the partner half-bivalent moved normally, i.e. in 9/12 cells the interzonal irradiations uncoupled the movements of the partner half-bivalents. In other double irradiation experiments we irradiated the spindle fibre first and the interzone second: in 80% (4/5) of the cells the half-bivalents not associated with the irradiated spindle fibre resumed movement immediately after the irradiation while the other half-bivalent remained stopped. Interzonal irradiations therefore uncouple the poleward movements of sister half-bivalents and the uncoupling does not depend on the order of the irradiation. Our experiments suggest therefore that the irradiation of a spindle fibre causes negative (‘stop’) signals to be transmitted across the interzone and that irradiation of the interzone blocks the transmission of the stop signal.
3
Jadwiszczak, Jakub, Pierce Maguire, Conor P. Cullen, Georg S. Duesberg e Hongzhou Zhang. "Effect of localized helium ion irradiation on the performance of synthetic monolayer MoS2 field-effect transistors". Beilstein Journal of Nanotechnology 11 (4 settembre 2020): 1329–35. http://dx.doi.org/10.3762/bjnano.11.117.
Abstract (sommario):
Helium ion irradiation is a known method of tuning the electrical conductivity and charge carrier mobility of novel two-dimensional semiconductors. Here, we report a systematic study of the electrical performance of chemically synthesized monolayer molybdenum disulfide (MoS2) field-effect transistors irradiated with a focused helium ion beam as a function of increasing areal irradiation coverage. We determine an optimal coverage range of approx. 10%, which allows for the improvement of both the carrier mobility in the transistor channel and the electrical conductance of the MoS2, due to doping with ion beam-created sulfur vacancies. Larger areal irradiations introduce a higher concentration of scattering centers, hampering the electrical performance of the device. In addition, we find that irradiating the electrode–channel interface has a deleterious impact on charge transport when contrasted with irradiations confined only to the transistor channel.
4
Kotsina, Z., G. Apostolopoulos, K. Mergia, S. Messoloras, A. Lagoyannis e S. Harissopulos. "Radiation damage studies of Fe-Cr alloys for Fusion applications using ion beams". HNPS Proceedings 20 (1 dicembre 2012): 55. http://dx.doi.org/10.12681/hnps.2487.
Abstract (sommario):
Ferritic-martensitic steels are considered as prime candidates for the first wall and blanket structural materials in future Fusion Power Plants. They are based on Fe-Cr alloys with Cr concentration up to 15%. Therefore, as a first step towards understanding the irradiation behaviour of these steels, the study of pure Fe-Cr alloys as a model system plays an important role. The flexibility offered by ion beams in accurately defining irradiation conditions, allows us to perform controlled experiments that will aid in the validation of recent theories of radiation damage.Radiation damage studies of Fe-Cr alloys were performed at the TANDEM accelerator of NCSR "Demokritos" by using a 5MeV proton beam directly on the sample and reaching fluences of ~1016 protons/cm2. A specialized irradiation facility has been developed at the TANDEM accelerator with good control of irradiation temperature and with the additional capability of measuring the electrical resistivity of the sample in-situ during irradiation, to directly asses the radiation damage evolution. Proton irradiations were carried out from cryogenic temperatures of 40K up to 400K. In alloys under irradiation, apart from the lattice damage created by the irradiating particles, the large amount of energy imparted locally to atomic sites may lead to a redistribution of solutes. It is expected that at cryogenic temperature solute redistribution will be greatly suppressed, since atomic movement is completely "frozen". Comparing the results of low and high temperature irradiations enables us to distinguish between the two sources of radiation induced changes to the alloy.
5
Tripathi, S. K., Jagdish Kaur, R. Ridhi, Kriti Sharma e Ramneek Kaur. "Radiation Induced Effects on Properties of Semiconducting Nanomaterials". Solid State Phenomena 239 (agosto 2015): 1–36. http://dx.doi.org/10.4028/www.scientific.net/ssp.239.1.
Abstract (sommario):
The irradiation of nanomaterials with energetic particles has significant effects on the properties of target materials. In addition to the well-known detrimental effects of irradiations, they have also some beneficial effects on the properties of nanomaterials. Irradiation effect can change the morphology of the materials in a controlled manner and tailor their mechanical, structural, optical and electrical properties. Irradiation induced modifications in the properties of nanomaterials can be exploited for many useful applications. With the aim of getting better performance of electronic devices, it is necessary to discuss the irradiation induced changes in the nanomaterials. In order to improve the irradiation hardness of electronic components, it is also crucial to have a fundamental understanding of the impact of the irradiation on the defect states and transport properties of the host material. In the present article, we review some recent advances on the irradiation induced effects on the properties of semiconducting nanomaterials. We have reviewed the effect of different types of irradiations which includes γ-irradiation, electron beam irradiation, laser irradiation, swift heavy ion irradiations, thermal induced, and optical induced irradiations, etc. on the various properties of semiconducting nanomaterials. In addition, the irradiation induced defects are also discussed.
6
Girard-Perier, Nina, Samuel Dorey, Sylvain R. A. Marque e Nathalie Dupuy. "Mapping the scientific research on the ionizing radiation impacts on polymers (1975–2019)". e-Polymers 21, n. 1 (1 gennaio 2021): 770–78. http://dx.doi.org/10.1515/epoly-2021-0065.
Abstract (sommario):
Abstract A bibliometric approach allowed us to study the global research trend on the impact of ionizing irradiations on polymers from 1975 to 2019. The investigation revealed 1,015 publications with growing interest since 1990. The research is split into three main categories: polymer science, nuclear science technology, and chemistry physical. The three main ionizing irradiations studied in this research are gamma, electron beam, and X-ray irradiations. The impact of ionizing irradiations on polymers under gamma irradiation is the most commonly studied field with 578 publications among the 1,015 publications. Electron beam irradiation is the second most studied field followed by X-ray irradiation. Whatever the irradiation modalities, publications focus on material degradation and material improvement studies.
7
Rodriguez Gual, Maritza, Amir Zacarias Mesquita, Edson Ribeiro e Pablo Andrade Grossi. "Shielding Verifications for a Gamma Irradiation Facility Considering the Installation of a New Automatic Product Loading System". Science and Technology of Nuclear Installations 2017 (2017): 1–6. http://dx.doi.org/10.1155/2017/7408645.
Abstract (sommario):
A new system has been designed to automatically load the samples to be irradiated at the gamma irradiation facility of the Nuclear Technology Development Centre (CDTN) at Belo Horizonte, Brazil. The objective of this system is the optimization of the experiments performed at the Gamma Irradiation Laboratory for short-time irradiations without interruption of the irradiator cycles. The installation of this new system requires the opening of a hole at the labyrinth door to allow the loading of irradiating products. Due to this alteration on the original design, the door opening into the labyrinth requires shielding verification. The dose rate with the door open is calculated using Monte Carlo MCNPX v 2.6.0 code. The Monte Carlo source simulations were validated with experimental measurements of dose rate. The simulation demonstrated that a hole can be opened at the labyrinth entrance when installing an automatic loading system. Not only does it comply with dose constraint requirements, but it also complies with national and international standards.
8
Li, Cheng Liang, Guo Gang Shu, Jing Li Yan, Wei Liu e Yuan Gang Duan. "Effects of Neutron, Ion and Proton Irradiation on Nano-Indentation Hardness of RPV Steels". Materials Science Forum 999 (giugno 2020): 39–46. http://dx.doi.org/10.4028/www.scientific.net/msf.999.39.
Abstract (sommario):
The irradiation embrittlement damage of reactor pressure vessel (RPV) steel is one of its primary failure mechanisms. In this work, neutron, ion and proton irradiation experiments were carried on the same commercial RPV steels with the same irradiation fluence under the same temperature of 292°C. Then the nano-indentation hardness tests were performed on the RPV steel before and after irradiation. The results show that the irradiation hardening effects are observed by means of nano-indentation technique under the above three irradiations, and the hardening features are basically the same. While the max variation and increase rate are obviously different between those irradiations. It is found that the main reason of the above differences are caused by different energies of irradiation energetic particles, resulting in different types and quantities of defects. The conclusions in this paper are helpful to select and compare different irradiation experiments to the research of RPV steels irradiation embrittlement damage.
9
Huang, Yuan Ming, Fu Fang Zhou e Bao Gai Zhai. "Effects of Red and Green Laser Irradiations on the Optical Properties of an Azo-Containing Bent-Core Liquid Crystal". Key Engineering Materials 428-429 (gennaio 2010): 588–92. http://dx.doi.org/10.4028/www.scientific.net/kem.428-429.588.
Abstract (sommario):
With the ultraviolet-visible spectrophotometry, we have investigated the effects of red laser (633 nm) and green laser (532 nm) irradiations on the optical absorption of the ethyl alcohol solutions of an azo-containing bent-core liquid crystal. As the irradiation duration increases, the optical absorptions at about 360 nm of the bent-core compound exhibit concentration dependent and irradiation-time dependent features. The absorptions of dilute solutions (~2.2 mg/litter) are not sensitive to the laser irradiation duration whereas the absorptions of higher concentrations (~10 mg/litter) decrease as the laser irradiation continues. Our results have demonstrated that laser irradiation induced thermolysis is responsible for the dissociation of the azo-linkages in azo-containing bent-core compound. The mechanisms on the red and green light irradiations are discussed.
10
Munir, Muhammad Tanveer, e Michel Federighi. "Control of Foodborne Biological Hazards by Ionizing Radiations". Foods 9, n. 7 (3 luglio 2020): 878. http://dx.doi.org/10.3390/foods9070878.
Abstract (sommario):
Ionization radiations are used to ensure food safety and quality. This irradiation process uses ions of beta or gamma rays to inactivate or destroy the food spoilage pests, microorganisms and their toxins without significantly increasing the temperature of the treated product. Meanwhile, various intrinsic and extrinsic factors are involved in determining the efficacy of ionization irradiation against these organisms. Therefore, the dose of radiations is recommended according to the type of irradiation, substrate and microorganisms. However, controversies are surrounding the use of irradiations in the food industry due to a negative perception of irradiations. This manuscript described the use of ionization radiations to control the foodborne biological hazards and increase shelf life. Firstly, the characteristics and mode of action of irradiations were discussed. Secondly, the role of extrinsic and intrinsic factors influencing the radioresistance of biological hazards were elaborated. This literature review also detailed the differential effects of irradiations on different microorganisms and pests having a role in food safety and deterioration. Finally, the regulatory status and the consumer values along with the controversies surrounding the use of ionization irradiations in the food sector were explained.
11
Safari, Mehdi, Ricardo J. Alves de Sousa e Jalal Joudaki. "Experimental Investigation of the Effects of Irradiating Schemes in Laser Tube Bending Process". Metals 11, n. 7 (15 luglio 2021): 1123. http://dx.doi.org/10.3390/met11071123.
Abstract (sommario):
The laser tube bending process (LTBP) process is a thermal non-contact process for bending tubes with less springback and less thinning of the tube. In this paper, the laser tube bending process will be studied experimentally. The length of irradiation and irradiation scheme are two main affecting process parameters in the LTBP process. For this purpose, different samples according to two main irradiation schemes (Circular irradiating scheme (CIS) and axial irradiating scheme (AIS)) and different lengths of laser beam irradiation (from 4.7 to 28.2 mm) are fabricated. The main bending angle of laser-bent tube, lateral bending angle, ovality, and thickness variations is measured experimentally, and the effects of the irradiating scheme and the length of irradiation are investigated. An 18 mm diameter, 1 mm thick mild steel tube was bent with 1100 Watts laser beam. The results show that for both irradiating schemes, by increasing the irradiating length of the main and lateral bending angle, the ovality and thickness variation ratio of the bent tube are increased. In addition, for a similar irradiating length, the main bending angle with AIS is considerably higher than CIS. The lateral bending angle by AIS is much less than the lateral bending angle with CIS. The results demonstrate that the ovality percentage and the thickness variation ratio for the laser-bent tube obtained by CIS are much more than the values associated with by AIS laser-bent tube.
12
Кожемяко, А. В., А. П. Евсеев, Ю. В. Балакшин e А. А. Шемухин. "Особенности дефектообразования в наноструктурированном кремнии при ионном облучении". Физика и техника полупроводников 53, n. 6 (2019): 810. http://dx.doi.org/10.21883/ftp.2019.06.47734.9050.
Abstract (sommario):
Irradiations of the nanostructured silicon with Si+ and He+ ions were carried out with energies of 200 and 150 keV, respectively. Raman scattering showed destruction of the structure after irradiations and accumulation of defects at different fluences of irradiation. It is shown that monocrystalline silicon films are amorphized under irradiation at 0.7 displacement per atom. However, porous silicon does not completely amorphize at 0.5 displacement per atom, a weak signal is observed in the Raman spectra corresponding to the amorphous silicon phase, and at the same time there is an obvious signal from the crystalline phase of silicon. The size of nanocrystallites in the structure of porous silicon was estimated at different fluences of irradiation.
13
Maziasz, P. J., D. F. Pedraza, J. P. Simmons e N. H. Packan. "Temperature dependence of the amorphization of NiTi irradiated with Ni ions". Journal of Materials Research 5, n. 5 (maggio 1990): 932–41. http://dx.doi.org/10.1557/jmr.1990.0932.
Abstract (sommario):
NiTi was irradiated with Ni ions at various temperatures in order to study the temperature dependence of the irradiation-induced crystalline-to-amorphous transition. The irradiations were conducted above the Af temperature, and thus the specimens contained only the ordered B2 (CsC1) phase. The irradiations to similar doses at 150, 200, and 250°C showed that the amorphization kinetics slow down appreciably as the temperature is increased in this range. No amorphization was detected at irradiation temperatures of 350°C or higher, even after doses of 4 dpa. The small volume fraction of amorphous material observed after irradiation to 0.67 dpa at 250°C indicates that the cutoff temperature for amorphization is in the vicinity of this temperature. The amorphous regions of partly amorphous samples are distributed in a nonuniform manner and exhibit a morphology similar to the martensitic microstructure that existed in the specimens before heating to the irradiation temperature. Large amorphous regions in these samples exhibit some very fine crystalline debris which tends to disappear with increasing irradiation dose. Post-irradiation annealing experiments indicated that no thermally activated crystallization occurred during irradiation at temperatures up to 250°C.
14
Zhu, Jun, e Yin Zhong Shen. "The Effect of Fe-Ion Irradiation on Hardness Changes in P92 Ferritic/Martensitic Steel". Applied Mechanics and Materials 446-447 (novembre 2013): 418–21. http://dx.doi.org/10.4028/www.scientific.net/amm.446-447.418.
Abstract (sommario):
The irradiation-induced hardness change in a commercial P92 ferritic/martensitic steel has been investigated through 3.5MeV Fe-ions irradiations to a dose of 0.29dpa at room temperature, 673K and 973K combined with nanoindentation techniques. The results show that irradiation-induced hardening was observed at the room temperature, and softening occurred at 673K and 973K. The hardening at room temperature is ascribed to the crystal defects in the steel generated by Fe-ions irradiations. The softening at 673K and 973K may be caused by the recovery of the defects.
15
Hosemann, Peter. "Studying Radiation Damage in Structural Materials by Using Ion Accelerators". Reviews of Accelerator Science and Technology 04, n. 01 (gennaio 2011): 161–82. http://dx.doi.org/10.1142/s1793626811000513.
Abstract (sommario):
Radiation damage in structural materials is of major concern and a limiting factor for a wide range of engineering and scientific applications, including nuclear power production, medical applications, or components for scientific radiation sources. The usefulness of these applications is largely limited by the damage a material can sustain in the extreme environments of radiation, temperature, stress, and fatigue, over long periods of time. Although a wide range of materials has been extensively studied in nuclear reactors and neutron spallation sources since the beginning of the nuclear age, ion beam irradiations using particle accelerators are a more cost-effective alternative to study radiation damage in materials in a rather short period of time, allowing researchers to gain fundamental insights into the damage processes and to estimate the property changes due to irradiation. However, the comparison of results gained from ion beam irradiation, large-scale neutron irradiation, and a variety of experimental setups is not straightforward, and several effects have to be taken into account. It is the intention of this article to introduce the reader to the basic phenomena taking place and to point out the differences between classic reactor irradiations and ion irradiations. It will also provide an assessment of how accelerator-based ion beam irradiation is used today to gain insight into the damage in structural materials for large-scale engineering applications.
16
Sumino, Y., H. Watanabe e Naoaki Yoshida. "The Microstructure of Pure Copper after Stepwise Change of Irradiation Temperature". Materials Science Forum 475-479 (gennaio 2005): 1479–82. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.1479.
Abstract (sommario):
In order to investigate the effect of stepwise change of irradiation temperature on pure copper, heavy ion irradiations under constant temperature and varying temperature conditions were performed. Specimens were irradiated up to 10dpa. In the temperature region of 473K ~ 673K, one-step temperature variation and periodic temperature variations were performed during irradiation. The resulting microstructures were compared with those induced by the irradiation at the constant temperature of 673K.
17
Zhu, Jun, e Yin Zhong Shen. "Irradiation Hardening in Ferritic/Martensitic Steel P92 during Ar-Ions Irradiation at Elevated Temperature". Applied Mechanics and Materials 378 (agosto 2013): 289–92. http://dx.doi.org/10.4028/www.scientific.net/amm.378.289.
Abstract (sommario):
The irradiation hardening behavior in a commercial ferritic/martensitic steel P92 has been investigated through 250KeV Ar-ions irradiations to a dose of 10dpa at 473, 673 and 973K combined with nanoindentation techniques. The results show that irradiation-induced hardening was observed at the all irradiation temperatures. There appear to have no previous reports of the irradiation-induced hardening at the temperature higher than 873K in ferritic/martensitic steels. Irradiation-induced hardening at elevated temperature of 973K has been found, for the first time, in ferritic/martensitic steel. The irradiation-induced hardening at 973K in the ferritic/martensitic steel P92 may be ascribed to the defects in the steel generated by Ar-ions irradiation.
18
Namour, Amaury, Marwan El Mobadder, Patrick Matamba, Lucia Misoaga, Delphine Magnin, Praveen Arany e Samir Nammour. "The Safety of Removing Fractured Nickel–Titanium Files in Root Canals Using a Nd: YAP Laser". Biomedicines 12, n. 5 (7 maggio 2024): 1031. http://dx.doi.org/10.3390/biomedicines12051031.
Abstract (sommario):
The fracture of nickel–titanium (Ni-Ti) instruments during root canal instrumentation leads to compromised outcomes in endodontic treatments. Despite the significant impact of instrument facture during a root canal treatment, there is still no universally accepted method to address this complication. Several previous studies have shown the ability of a Neodymium: Yttrium–Aluminum–Perovskite (Nd: YAP) laser to cut endodontic files. This study aims to determine safe irradiation conditions for a clinical procedure involving the use of a Neodymium: Yttrium–Aluminum–Perovskite (Nd: YAP) laser for removing fractured nickel–titanium files in root canals. A total of 54 extracted permanent human teeth (n = 54) were used. This study involved nine distinct groups, each employing different irradiation conditions. Groups 1 s, 3 s, 5 s, 10 s, and 15 s simply consist of irradiation for 1, 3, 5, 10, and 15 s, respectively. After identifying the longest and safest duration time, four additional groups were proposed (labeled A, B, C, and D). Group A was composed of three series of irradiations of 5 s each separated by a rest time of 30 s (L5s + 30 s RT). Group B consisted of three series of irradiations of 5 s each separated by a rest time of 60 s (L5s + 60 s RT). Group C consisted of two series of irradiations of 5 s each separated by a rest time of 30 s (L5s + 30 s RT), and group D consisted of two series of irradiations of 5 s each separated by a rest time of 5 s (L5s + 5 s RT). In all groups, during the rest time, continuous irrigation with 2.5 mL of sodium hypochlorite (3% NaOCl) was carried out. The variation in temperature during irradiation was registered with a thermocouple during irradiation with different protocols. The mean and standard deviation of the temperature increase was noted. The calculation of the temperature was made as the Δ of the highest recorded temperature at the root surface minus (-) that recorded at baseline (37°). Additionally, scanning electron microscopy (SEM) was used after irradiation in all groups in order to assess the morphological changes in the root dentinal walls. The Nd: YAP laser irradiation parameters were a power of 3W, an energy of 300 mJ per pulse, a fiber diameter of 200 µm, a pulsed mode of irradiation with a frequency of 10 Hz, a pulse duration of 150 𝜇s, and an energy density of 955.41 J/cm2. Our results show that the safest protocol for bypassing and/or removing broken instruments involves three series of irradiation of 5 s each with a rest time of 30 s between each series. Furthermore, our results suggest that continuous irradiation for 10 s or more may be harmful for periodontal tissue.
19
Muroga, Takeo. "Challenge to Performance Evaluation of Fusion Reactor Materials by Fission Neutron and Charged Particle Irradiation". Materials Science Forum 1106 (5 dicembre 2023): 95–101. http://dx.doi.org/10.4028/p-kh9ip1.
Abstract (sommario):
Since there are no fusion reactors generating high-flux 14 MeV neutrons, it is necessary to evaluate materials’ performance in fusion reactors based on a correlation of fission neutron and charged particle irradiations. However, the irradiation tests involve various issues which prevent simple correlation and evaluation. In this paper, the issues related to irradiation temperature control and dose rate effects are pointed out and analyzed, and proposals regarding future irradiation tests are given.
20
Chen, Guo, Wei, Xie e Long. "Effect of Strengthening Methods on the Defect Evolution under Irradiations Investigated with Rate Theory Simulations". Metals 9, n. 7 (29 giugno 2019): 735. http://dx.doi.org/10.3390/met9070735.
Abstract (sommario):
Under irradiations, mechanical performance of nuclear alloys would degrade due to irradiation induced defects. Different strengthening methods can play a different role in the evolution of the defects. In this study, the effect of four typical strengthening methods including fine grain strengthening, dislocation strengthening, second phase strengthening and solid solutions strengthening on the defect evolutions in bcc iron-based alloys are investigated with rate theory simulations, a technique capable of simulating a long-term evolution of defects caused by irradiations. Simulations show that at high dose, irradiation induced voids become the dominating factor that affect irradiation hardening. Strengthening methods with the enhancement of sink strength (fine grain strengthening, dislocation strengthening and second phase strengthening) have little effects on the evolution of voids, while strengthening method with impediment of migration of defects (solid solutions strengthening) can effectively inhibit the nucleation and growth of voids. For fine grain strengthening and dislocation strengthening, the irradiation hardening is almost kept unchanged when changing grain size and initial dislocation density. For second phase strengthening, the irradiation hardening can be inhibited to some extent by increasing mainly the number density of precipitates. The solid solutions strengthening is the most proper method to inhibit irradiation hardening of bcc iron-based alloy because it can inhibit the development of voids, especially at high dose.
21
Degerblad, M., T. Rähn, G. Bergstrand e M. Thorén. "Long-term results of stereotactic radiosurgery to the pituitary gland in Cushing's disease". Acta Endocrinologica 112, n. 3 (luglio 1986): 310–14. http://dx.doi.org/10.1530/acta.0.1120310.
Abstract (sommario):
Abstract. Gamma radiation from 60Co delivered with stereotactic technique was given to the pituitary gland in 35 patients, aged 18–65 years, with Cushing's disease. The doses were 70– 100 Gy in each single irradiation. The size of the sella turcica was normal in the majority of the patients. The observation time was 3–9 years in 29 patients. Out of them, 14 (48%) obtained clinical remission and normal urinary cortisol after one irradiation. Eight achieved remission after two to four irradiations. In total, 22 out of 29 patients (76%) obtained remission. In 12 of them remission was obtained in 1 year and in another 10 within 3 years. No recurrences were observed. Improvement was seen in 2 patients after one and three irradiations. Bilateral adrenalectomy was performed in 5 patients owing to unsatisfactory effect of irradiation. Pituitary insufficiency with gonadotropin, thyrotropin or corticotropin failure was demonstrated in 12 of 22 patients in remission. This occurred 4 months to 7 years after the first irradiation. Another 6 patients were followed less than 3 years after the first irradiation. Two obtained remission after the first treatment, whereas the other 4 improved. Stereotactic pituitary irradiation is suggested as a non-invasive therapeutic alternative in Cushing's disease for example in patients with considerable surgical risk or as a supplement to pituitary microsurgery.
22
Yarita, Masafumi, Kayoko Kitajima, Takao Morita e Koichi Shinkai. "Effects of Semiconductor Laser Irradiation on Differentiation of Human Dental Pulp Stem Cells in Co-Culture with Dentin". Dentistry Journal 12, n. 3 (5 marzo 2024): 67. http://dx.doi.org/10.3390/dj12030067.
Abstract (sommario):
This study aimed to determine the effect of photobiomodulation therapy induced by semiconductor laser irradiation on human dental pulp stem cell (hDPSC) proliferation and their differentiation into odontoblast-like cells (OLCs). The effects of various semiconductor laser irradiation conditions on hDPSCs were examined. Three groups were evaluated: a single laser irradiation at 6 h post-seeding, multiple laser irradiations up to four times every 4 days after the first dose, and a control with no laser irradiation. The cells were irradiated at 10, 30, and 150 mW using a semiconductor laser. The effect of laser irradiation on hDPSC differentiation into OLCs was also determined. Four groups were evaluated, including co-culture using basic medium and dentin discs, simple culture using OLC differentiation-inducing medium, co-culture using OLC differentiation-inducing medium and dentin discs, and control culture with basic medium. The expression of the nestin, ALP, DSPP, and DMP-1 genes was measured using real-time PCR. The multiple irradiation group irradiated at 30 mW exhibited significantly more cell proliferation than the control. The expression of nestin associated with differentiation into OLCs during each culture period tended to be lower, whereas DSPP and ALP expression was higher compared with that of the control. Multiple laser irradiations at a low power of 30 mW induced significant hDPSC proliferation and might induce differentiation into OLCs.
23
ZHU, SHENGYUN, T. IWATA, YONGJUN XU, YONGNAN ZHENG, DONGMEI ZHOU, JIAZHENG ZHU, ZHIQQIANG WANG, DAQING YUAN, ENPENG DU e YI ZUO. "EXPERIMENTAL VERIFICATION OF HEAVY ION IRRADIATION SIMULATION". Modern Physics Letters B 18, n. 17 (30 luglio 2004): 881–85. http://dx.doi.org/10.1142/s0217984904007359.
Abstract (sommario):
The heavy ion irradiation simulation of neutron and/or proton irradiation has been verified experimentally by the detailed study of radiation damage in α- Al 2 O 3 irradiated at the equivalent dose by 5.28×1015 cm -285 MeV 19 F ions and by 3×1020 cm -2 En≥1 MeV neutrons, respectively. The radiation damage created by irradiation was examined by a positron annihilation lifetime technique. The positron annihilation parameters of lifetime and intensity obtained for both irradiations in α- Al 2 O 3 are all in good agreement. This demonstrates that the heavy ion irradiation can well simulate the neutron and/or proton irradiation.
24
Marquezan, Mariana, Ana Maria Bolognese e Mônica Tirre de Souza Araújo. "Evaluation of two protocols for low-level laser application in patients submitted to orthodontic treatment". Dental Press Journal of Orthodontics 18, n. 1 (febbraio 2013): 33e1–33e9. http://dx.doi.org/10.1590/s2176-94512013000100009.
Abstract (sommario):
INTRODUCTION: Different low-level laser (LLL) irradiation protocols have been tested to accelerate orthodontic tooth movement (OTM). Nevertheless, divergent results have been obtained. It was suggested that the stimulatory action of low level laser irradiation occurs during the proliferation and differentiation stages of bone cellular precursors, but not during later stages. OBJECTIVE: The purpose of this study was to determine the effect of two protocols of LLL irradiation on experimental tooth movement: One with daily irradiations and another with irradiations during the early stages. METHODS: Thirty-six rats were divided into control groups (CG1, CG2, CG3) and irradiated groups (IrG1, IrG2, IrG3) according to the presence of: experimental tooth movement, laser irradiation, type of laser irradiation protocol and date of euthanasia (3th or 8th day of experiment). At the end of experimental periods, a quantitative evaluation of the amount of OTM was made and the reactions of the periodontium were analyzed by describing cellular and tissue reactions and by counting blood vessels. RESULTS: The amount of OTM revealed no significant differences between groups in the same experimental period (p < 0.05). Qualitative analysis revealed the strongest resorption activity in irradiated groups after seven days, especially when using the daily irradiation protocol. There was a higher number of blood vessels in irradiated animals than in animals without orthodontic devices and without laser irradiation (p < 0.05). CONCLUSION: Moreover, angiogenesis was verified in some of the irradiated groups. The irradiation protocols tested were not able to accelerate OTM and root resorption was observed while they were applied.
25
Khatib, Tamer, Azah Mohamed, K. Sopian e M. Mahmoud. "Solar Energy Prediction for Malaysia Using Artificial Neural Networks". International Journal of Photoenergy 2012 (2012): 1–16. http://dx.doi.org/10.1155/2012/419504.
Abstract (sommario):
This paper presents a solar energy prediction method using artificial neural networks (ANNs). An ANN predicts a clearness index that is used to calculate global and diffuse solar irradiations. The ANN model is based on the feed forward multilayer perception model with four inputs and one output. The inputs are latitude, longitude, day number, and sunshine ratio; the output is the clearness index. Data from 28 weather stations were used in this research, and 23 stations were used to train the network, while 5 stations were used to test the network. In addition, the measured solar irradiations from the sites were used to derive an equation to calculate the diffused solar irradiation, a function of the global solar irradiation and the clearness index. The proposed equation has reduced the mean absolute percentage error (MAPE) in estimating the diffused solar irradiation compared with the conventional equation. Based on the results, the average MAPE, mean bias error and root mean square error for the predicted global solar irradiation are 5.92%, 1.46%, and 7.96%. The MAPE in estimating the diffused solar irradiation is 9.8%. A comparison with previous work was done, and the proposed approach was found to be more efficient and accurate than previous methods.
26
Kang, Hye Jin, Yoo-Kang Kwak, So Jung Lee e Myungsoo Kim. "Re-Irradiation with Intensity-Modulated Radiation Therapy for the Treatment of Recurrent Cervical Cancer in the Pelvis: An Analysis of Outcomes and Toxicity". Medicina 59, n. 6 (17 giugno 2023): 1164. http://dx.doi.org/10.3390/medicina59061164.
Abstract (sommario):
Background and Objectives: Treatment options for most patients with recurrent cervical cancer within the previously irradiated field are limited. This study aimed to investigate the feasibility and safety of re-irradiation using intensity-modulated radiation therapy (IMRT) for patients with cervical cancer who experienced intrapelvic recurrence. Materials and Methods: We retrospectively analyzed 22 patients with recurrent cervical cancer who were treated with re-irradiation for intrapelvic recurrence using IMRT between July 2006 and July 2020. The irradiation dose and volume were determined based on the range considered safe for the tumor size, location, and previous irradiation dose. Results: The median follow-up period was 15 months (range: 3–120) and the overall response rate was 63.6%. Of the symptomatic patients, 90% experienced symptom relief after treatment. The 1- and 2-year local progression-free survival (LPFS) rates were 36.8% and 30.7%, respectively, whereas the 1- and 2-year overall survival (OS) rates were 68.2% and 25.0%, respectively. Multivariate analysis revealed that the interval between irradiations and gross tumor volume (GTV) were significant prognostic factors for LPFS. The response to re-irradiation showed borderline statistical significance for LPFS. The GTV and response to re-irradiation were also independent prognostic factors for OS. Grade 3 late toxicities were observed in 4 (18.2%) of the 22 patients. Recto- or vesico-vaginal fistula occurred in four patients. The irradiation dose was associated with fistula formation with borderline significance. Conclusions: Re-irradiation using IMRT is a safe and effective treatment strategy for patients with recurrent cervical cancer who previously received RT. Interval between irradiations, tumor size, response to re-irradiation, and radiation dose were the main factors affecting efficacy and safety.
27
Meilij, R., E. Aon e M. Valente. "A METHODOLOGY FOR DEFINING IRRADIATION SCHEMES FROM PHASE-SPACE FILES TO SIMULATE RADIOTHERAPY PLANNING". Anales AFA 33, n. 2 (15 luglio 2022): 48–53. http://dx.doi.org/10.31527/analesafa.2022.33.2.48.
Abstract (sommario):
The complex planning processes in radiotherapy treatments are commonly approached using computer tools that determine the dose distribution corresponding to different irradiation schemes aimed at providing viable options to fulfill the clinical and physical requirements of each case. This paper reports on a novel methodology developed to calculate spatial distributions of doses corresponding to stereotactic irradiations, incorporating arc-irradiation schemes and being representative of treatment planning, by means of phase-Spacefiles; and using Monte Carlo simulations to perform radiation transport. The methodology was implemented with the FLUKA code and was applied to a situation of clinical complexity using tomographic images of a standardized dosimetry control phantom for stereotactic radiosurgery. The preliminary results obtained from the first step of the process, aimed at incorporating simple schemes, along with clinical radiosurgery phantom irradiation, confirm the feasibility of the proposed methodology and indicate a promising performance for an alternative or independent calculation of spatial dose distributions in stereotactic irradiations.
28
Weill, Federico S., Eliana M. Cela, Mariela L. Paz, Alejandro Ferrari, Juliana Leoni e Daniel H. González Maglio. "Lipoteichoic acid from Lactobacillus rhamnosus GG as an oral photoprotective agent against UV-induced carcinogenesis". British Journal of Nutrition 109, n. 3 (6 luglio 2012): 457–66. http://dx.doi.org/10.1017/s0007114512001225.
Abstract (sommario):
Probiotics are live micro-organisms that when administered in adequate amounts confer a health benefit on the host. Cell surface molecules of these micro-organisms are being studied in relation to their ability to interact with the host. The cell wall of lactobacilli possesses lipoteichoic acids (LTA) which are molecules with immunomodulatory properties. UV radiation (UVR) has been proposed as the main cause of skin cancer because of its mutagenic and immunosuppressive effects. Photoprotection with some nutrition interventions including probiotics has recently been shown. The aim of the present study was to investigate whether the oral administration of purified LTA from Lactobacillus rhamnosus GG can modulate the immune-suppressive effect of UVR and skin tumour development in female Crl:SKH-1-hrBR mice. For this purpose, two irradiation models were studied: (1) a chronic irradiation scheme consisting of daily irradiations during twenty consecutive days and (2) a long-term irradiation schedule, irradiating the animals three times per week, during 34 weeks for tumour development. The results showed that T-cells in the inguinal lymph node of LTA-treated mice produced higher levels of (1) interferon-γ and (2) a number of total, helper and cytotoxic T-cells compared with non-treated mice. Moreover, a significant delay in tumour appearance was found in LTA-treated mice. An increased IgA+ cell number was found in the small intestine together with a higher number of activated dendritic cells in the mesenteric lymph nodes. The latter results might be indicative of a direct effect of LTA in the gut, affecting the cutaneous immune system and restoring homeostasis through the gut–skin axis.
29
MATSUDA, Y., M. YONEZAWA e F. NISHIYAMA. "PIXE ANALYSIS OF BONE MARROW IN MICE ACQUIRED RADIORESISTANCE AFTER PRE-IRRADIATION WITH SMALL DOSE OF X-RAYS". International Journal of PIXE 08, n. 02n03 (gennaio 1998): 107–13. http://dx.doi.org/10.1142/s0129083598000133.
Abstract (sommario):
Pre-irradiation with 0.3-0.5 Gy of X-rays induces radioresistance (decreased bone marrow death) in ICR and C57BL strains of mice 2 weeks afterward. Recovery of blood cell counts of thrombocytes, leukocytes and erythrocytes was enhanced by the pre-irradiation. And the radio-resistance is acquired even in splenectomized C57BL mice. Elements in the bone marrow 11 days after the challenging dose of 5.0 Gy was determined by a PIXE analysis in three groups of mice: intact (with no irradiations), without pre-irradiation (control) and pre-irradiation (experimental) groups. Challenging irradiation decreased Mg , P , S , K , Ca and Zn levels, and the pre-irradiation enhanced the recovery of those levels, i.e. stimulated metabolism in bone marrow of irradiated mice. Increase in Fe in both control and experimental groups would indicate stimulated hemoglobin synthesis after challenging irradiation.
30
Nastasi, M., H. H. Johnson, J. W. Mayer e J. M. Williams. "Stability and formation of NiAl3 under ion irradiation". Journal of Materials Research 1, n. 2 (aprile 1986): 268–74. http://dx.doi.org/10.1557/jmr.1986.0268.
Abstract (sommario):
Compound samples of NiAl3 as well as Ni23Al77 multilayered samples have been irradiated by either Xe or Ne ions to doses of 2 × 1015 Xe ions/cm2 and 1.3 × 106 Ne ions/cm2 at temperatures of 100 K, 300 K, and 373 K. In the case of compound irradiation, NiAl3 stability appears to be determined by regrowth kinetics and increased with lighter irradiating ion mass and higher irradiation temperature. The formation of NiAl3 by ion mixing Ni/Al multilayers was not affected by irradiating ion mass and appears to be limited by nucleation.
31
Fina, Wahlia Fullah. "Variability Result Induction Of Ionization By Gamma Cobalt-60 Ray". Jurnal Biosains Pascasarjana 21, n. 2 (1 agosto 2019): 84. http://dx.doi.org/10.20473/jbp.v21i2.2019.84-94.
Abstract (sommario):
ABSTRACTThe research was conducted to study the effect of 60Co gamma irradiation to the growth of adenium (Apocynaceae sp.) and to findout the effective dose of gamma 60Co irradiation to adenium (Apocynaceae sp.). The research was designed using Completely Randomized Post Design with 5 groups of treatment and 4 replicants for every treatment with variation of irradiating dose 2, 6, 12 dan 20 gray, all treatment were observed every 3 weeks until 12 weeks. The growth of adenium (Apocynaceae sp.) : biomassa, high of crop and the number of leaf was analyzed by ANAVA and followed by Tuckey (Honestly Significant Difference) with α = 0,05% for high and dry weight crop, while the number of leaf were analyzed with Kruskal-Wallis with α = 0,05%, then was analyzed with regression test. The Results showed that the irradiating caused influence the increased of biomassa and high of adenium (Apocynaceae sp.) crop significantly at observation of week 3, 9 and 12. For number of leaf, irradiating dose giving no significant influence. The optimum doses of 60Co gamma irradiation for the growth of biomassa and high of adenium (Apocynaceae sp.) crop at observation of week 3, 9, and 12 were 6 gray. Keyword : 60Co, gamma irradiation, adenium (Apocynaceae sp.).
32
Girard-Perier, Nina, Sylvain R. A. Marque, Nathalie Dupuy, Blanche Krieguer e Samuel Dorey. "Gamma, E-Beam and X-ray Irradiations on PE/EVOH/PE Multilayer Film: An Industrial Point of View Regarding the Impact on Mechanical Properties". Polymers 15, n. 13 (24 giugno 2023): 2799. http://dx.doi.org/10.3390/polym15132799.
Abstract (sommario):
X-ray and electron-beam (E-beam) sterilization technologies were assessed to supplement gamma sterilization, the most common radiation technology used today for biopharmaceutical product sterilization. The mechanical properties of a PE/EVOH/PE film were studied using tensile tests and dynamical mechanical analysis after each irradiation technology (i.e., gamma, electron beam and X-ray irradiations). The effects of each irradiation were compared using two statistical methods. The results indicate that the three irradiation technologies induce no difference in mechanical properties in the investigated dose range for this material.
33
Popelářová, Eva, Eva Vlková, Roman Švejstil e Lenka Kouřimská. "The Effect of Microwave Irradiation on the Representation and Growth of Moulds in Nuts and Almonds". Foods 11, n. 2 (14 gennaio 2022): 221. http://dx.doi.org/10.3390/foods11020221.
Abstract (sommario):
Microwave (MW) irradiation is a non-destructive method that can be applied as an alternative method to inhibit the growth of microorganisms. The present study evaluated the effect of MW irradiation on the occurrence of moulds in nuts and almonds. Samples of unshelled natural almonds, pistachios, and in-shell peanuts were treated with different doses of MW irradiation (2400–4000 W). The effect of MW irradiation on mould counts was evaluated by cultivating immediately after irradiation and after 3 and 6 months of storage. The most represented genera in all analysed samples were Aspergillus (68%), Penicillium (21%), and a small amount of Cladosporium (3%). Mould numbers significantly decreased after MW treatment. The treatments with MW irradiations at 3000 and 4000 W significantly reduced the mould colony counts, and their effect persisted during storage; irradiation at 2400 W was partially effective. The strongest effect of MW irradiation was observed in in-shell peanuts. MW irradiation seems to be a promising method for maintaining the microbiological quality of nuts.
34
Yabuuchi, Kiyohiro, Masashi Saito, Ryuta Kasada e Akihiko Kimura. "Neutron Irradiation Hardening of Fe-Based Binary Alloys". Materials Science Forum 654-656 (giugno 2010): 2911–14. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.2911.
Abstract (sommario):
We investigated mechanical properties of neutron irradiated Fe based binary alloys in order to extract roles of each alloying element in reactor pressure vessel (RPV) steels on irradiation hardening and annealing recovery behavior. Materials used were Pure-Fe, Fe-1Cr, Fe-1Mn, Fe-1Ni, Fe-1Cu and Fe-1Mo in at.%. Neutron irradiations were carried out at various irradiation doses from 0.3 to 8.5 × 1019 n/cm2 ( > 1.0 MeV) at 290 °C. Irradiation hardening of Fe-1Cu showed a tendency of saturation at a low dose. Irradiation hardening of Pure-Fe and the other binary alloys increased with increasing in irradiation dose. Especially, Fe-1Mn irradiated over 4.3 × 1019 n/cm2 showed significant irradiation hardening which is comparable to Fe-1Cu. However, the post-irradiation annealing recovery behavior of the irradiation hardening in Fe-Mn showed one-stage recovery at around 450 °C, which was completely different from the two-stages recovery behavior of Fe-1Cu.
35
Czaban, B. B., e A. Forer. "The kinetic polarities of spindle microtubules in vivo, in crane-fly spermatocytes. II. Kinetochore microtubules in non-treated spindles". Journal of Cell Science 79, n. 1 (1 novembre 1985): 39–65. http://dx.doi.org/10.1242/jcs.79.1.39.
Abstract (sommario):
We determined the kinetic polarities of chromosomal spindle fibre microtubules in vivo: either the kinetochore or pole ends of chromosomal spindle fibres were irradiated with near-ultraviolet light to prevent depolymerization by colcemid. Irradiations began either just before or just after colcemid addition; cells were continually irradiated and continuously immersed in colcemid. Irradiations of kinetochore ends of chromosomal spindle fibres prevented depolymerization; irradiations of pole ends did not. Therefore, since colcemid acts by binding to the ‘on’ (assembly) ends of microtubules, the on ends of chromosomal spindle fibre microtubules are at the kinetochores. That is, in untreated chromosomal spindle fibres in vivo tubulin monomers add to kinetochore microtubules at the kinetochore ends. Tubulin diffused from the irradiation sites: irradiations of the cytoplasm sometimes prevented depolymerization of chromosomal spindle fibres. Prevention of chromosomal spindle fibre depolymerization was dependent on the distance of the irradiated region from the nearest chromosome; the longer the distance the less likely was it that the irradiation prevented depolymerization. On the other hand, prevention of chromosomal spindle fibre depolymerization was not dependent on the distance from the irradiated spot to the nearer pole. This analysis, too, we argue, strongly suggests that the kinetochore ends of the chromosomal spindle fibres are the on ends.
36
Chi, Yaqing, Chang Cai, Ze He, Zhenyu Wu, Yahao Fang, Jianjun Chen e Bin Liang. "SEU Tolerance Efficiency of Multiple Layout-Hardened 28 nm DICE D Flip-Flops". Electronics 11, n. 7 (22 marzo 2022): 972. http://dx.doi.org/10.3390/electronics11070972.
Abstract (sommario):
Three layout-hardened Dual Interlocked Storage Cell (DICE) D Flip-Flops (DFFs) were designed and manufactured based on an advanced 28 nm planar technology. The systematic vertical and tilt heavy ion irradiations demonstrated that the DICE structure contributes to radiation tolerance. However, it is hard to achieve immunity from a Single Event Upset (SEU), even when a ~3-µm well isolation is utilized. The SEU mitigation of the hardened DFFs was affected by the data patterns and clock signals due to the imbalance in the number of upset nodes. When the clock signal equalled 0, no error was observed in 181Ta irradiation, indicating that the DICE DFFs are SEU tolerant in vertical irradiation owing to their reasonable isolation of sensitive volumes. The divergences of SEU cross-sections were enlarged by our specially designed joint change of tilt incidences for both the along-cell and cross-cell irradiation of heavy ions. The evaluations of SEU for both the vertical and tilt irradiations assist with eliminating the overestimation of SEU tolerance and guarantee the in-orbit safety of spacecraft in harsh radiation environments.
37
Manzoli, José Eduardo, Valdir de Souza Carvalho e Eliomar Jacinto Gomes de Cerqueira. "Absorbed dose measurements using TLDS in biological samples from beta radiation". Brazilian Archives of Biology and Technology 49, spe (gennaio 2006): 47–52. http://dx.doi.org/10.1590/s1516-89132006000200008.
Abstract (sommario):
Irradiation of samples in peculiar experimental apparatus, subject to radiation spread, requires a special evaluation of absorbed dose implanted to the sample. Indirect calibration of the irradiation source, obtained in a different apparatus, and the spread, usually of very difficult theoretical evaluation, can cause very serious measurement errors, sometimes reaching 50%. In this work, the procedure for dose evaluation in an apparatus for beta irradiation of samples, usually biological ones,is presented, making use of calibration curves, obtained by irradiation in advance of thermoluminescent detectors in air, and so irradiating them in the same position of the sample. An application in blood sample irradiation is also presented.
38
Kang, Eun Byeol, Jin Chul Joo, So Ye Jang, Hyeon Woo Go, Jungsu Park, Dong-Ho Lee e Chang Hyuk Ahn. "Analysis of Growth Inhibition for Microcystis aeruginosa with Periodic Ultrasonic Irradiations". Journal of Korean Society of Environmental Engineers 45, n. 4 (30 aprile 2023): 190–200. http://dx.doi.org/10.4491/ksee.2023.45.4.190.
Abstract (sommario):
Objectives : To confirm both efficiency and sustainability of algal growth inhibition, various laboratory-scale experiments were conducted and the growth inhibitory effect of <i>Microcystis aeruginosa</i> (<i>M. aeruginosa</i>) was investigated through ultrasonic re-irradiation during the regrowth period after the first ultrasound irradiation.Methods : Experiments with different times of irradiation [i.e., control group A (0 hr), experimental group B (2 hr) applied with only the first ultrasound irradiation, and experimental group C (0.5 hr), D (1 hr), and E (1.5 hr) applied with both first and second irradiations] were performed.Results and Discussion : As a result of both Chlorophyll-<i>a</i> (Chl-<i>a</i>) concentration and cell number of <i>M. aeruginosa</i>, the experimental group (B) with only first ultrasound irradiation (2 hr) displayed rapid regrowth of algae after initial decrease whereas the experimental group (C, D, and E) with both first ultrasound irradiation (2 hr) and second ultrasound irradiation (0.5 hr, 1 hr, and 1.5 hr) confirmed the delay of algae regrowth. Based on the specific growth rate constant (<i>µ</i>) and first order decay rate constant (<i>k</i>), algal growth from the experimental groups (C, D, E) with the secondary ultrasound irradiation was more significantly inhibited due to repetitive inactivation of algae growth. According to the SEM and TEM results, damages to algae cells were clearly observed under the influence of ultrasound, and both decrease in gas vesicles and rupture of cell membrane in <i>M. aeruginosa</i> were also monitored.Conclusion : Through this study, the algae growth inhibitory effect by ultrasonic irradiations was confirmed, and the re-irradiation of ultrasound contributed to the repetitive inactivation of algae growth, indicating that the second ultrasonic irradiation time required to inhibit algal regrowth can be reduced compared to the first irradiation. Therefore, periodic ultrasonic irradiation is required for long-term inhibition of algae growth in stagnant waters, but the appropriate frequency of ultrasonic irradiation may vary depending on the influence of various complex factors such as the size of the stagnant waters, the frequency of algal blooms, water temperature, light irradiation, nutrients, flow rate, etc. Finally, many field studies under various conditions are warranted to establish an optimized ultrasound irradiation protocol.
39
Chani, Muhammad Tariq Saeed, Khasan S. Karimov, Abdullah M. Asiri, Tahseen Kamal, Esraa M. Bakhsh e Mohammed Muzibur Rahman. "Ultraviolet and Infrared Irradiations Sensing of Gel-Orange Dye Composite-Based Flexible Electrochemical Cells". Gels 8, n. 2 (28 gennaio 2022): 83. http://dx.doi.org/10.3390/gels8020083.
Abstract (sommario):
The flexible and shockproof rubber-based Al/OD-Gel/Cu electrochemical cell was designed, fabricated, and investigated for the detection of IR and UV irradiations. For this purpose, the transparent gel–orange dye composite was deposited on the porous rubber substrate between aluminum and copper electrodes. It was observed that the gel–orange dye composite was mechanically like a gel: soft and flexible. Electrically, this composite (gel–orange dye) forms a flexible electrolyte. It was found that the impedance of the samples under the effect of infrared irradiation decreased by 2.02 to 2.19 times on changing frequency from 100 Hz to 200 kHz. Accordingly, under the effect of ultraviolet irradiation, the impedance of the samples decreased by 1.23 to 1.45 times on increasing frequency from 100 Hz to 200 kHz. Under the effect of infrared irradiation up to 4000 W/m2, the cell’s open-circuit voltage increased by 1.59 times. The cell’s open-circuit voltage also increased by 1.06 times under the effect of ultraviolet irradiation up to 200 uW/cm2. The mechanism of the absorption of the infrared and ultraviolet irradiations by the OD–Gel composite has been discussed in detail. The fabricated flexible rubber substrate-based Al/OD-Gel/Cu electrochemical cells can be used as a prototype for the development of gel electronics-based devices.
40
Byun, Kye-Hwan, Min-Jung Cho, Shin-Young Park, Hyang Sook Chun e Sang-Do Ha. "Effects of gamma ray, electron beam, and X-ray on the reduction of Aspergillus flavus on red pepper powder (Capsicum annuum L.) and gochujang (red pepper paste)". Food Science and Technology International 25, n. 8 (18 giugno 2019): 649–58. http://dx.doi.org/10.1177/1082013219857019.
Abstract (sommario):
Aspergillus flavus is the potential pathogenic mold in red pepper powder ( Capsicum annuum L.) and gochujang (red pepper paste), which can produce mycotoxins. This study investigated the effects of gamma ray, e-beam, and X-ray irradiation on the reduction of A. flavus on red pepper powder and gochujang and physicochemical and sensory quality changes. Gamma ray and e-beam at 3.5 kGy reduced A. flavus effectively (>4 log), without deteriorating the physicochemical quality. Same dose of X-ray did not cause any deterioration of the physicochemical quality. However, reduction effect of A. flavus in red pepper powder and gochujang by 3.5 kGy X-ray was under 2 log. Further, sensory quality analysis showed no significant difference in color, appearance, texture, and overall acceptability after three irradiations. However, flavor changes of red pepper powder and gochujang after three irradiations were mentioned by panelists. In this study, gamma ray and e-beam irradiation were effective in eliminating A. flavus present in red pepper powder and gochujang, but X-ray irradiation was not effective. The results indicate gamma ray and e-beam are effective in controlling microorganisms present in powdery or paste foods, but the X-ray was not effective.
41
Iwamoto, Yosuke, e Shin-ichiro Meigo. "Calculation of athermal recombination corrected dpa cross sections for proton, deuteron and heavy-ion irradiations using the PHITS code". EPJ Web of Conferences 239 (2020): 20011. http://dx.doi.org/10.1051/epjconf/202023920011.
Abstract (sommario):
To provide the athermal recombination corrected dpa (arc-dpa) cross sections for proton, deuteron and heavy ion irradiations in the energy range from 1 MeV/u to 3 GeV/u., the defect production efficiencies for aluminium, copper and tungsten were implemented in the radiation damage model in PHITS. In general, the dpa cross section is large with increasing the number of protons of incident particle. For high-energy (around 1 GeV/u) proton and deuteron irradiation, the dpa cross section is close to that under 12C irradiation due to secondaries produced by the nuclear reaction. The ratio of arc-dpa cross section to the conventional Norgett-Robinson-Torrens dpa (NRT-dpa) cross section is around 0.2 with incident energies over 100 MeV for proton and deuteron irradiations. For the case of 12C and 48Ca, this ratio is ranged from 0.3 to 0.4 for incident beam energies below 3 GeV/u.
42
Frederiksen, Anders Tobias, Morten Bjørn Jensen, Per Rugaard Poulsen, Niels Bassler, Brita Singers Sørensen e Mateusz Sitarz. "Evaluation of in vitro irradiation setup: Designed for the horizontal beamline at the Danish Centre for Particle Therapy". Acta Oncologica 63 (13 febbraio 2024): 23–27. http://dx.doi.org/10.2340/1651-226x.2024.19657.
Abstract (sommario):
Background: Radiobiological experimental setups are challenged by precise sample positioning along depth dose profile, scattering conditions, and practical difficulties that must be addressed in individual designs. The aim of this study was to produce cell survival curves with several irradiation modalities, by using a setup designed at the Danish Centre for Particle Therapy (DCPT) for in vitro proton irradiations using a horizontal beam line and thereby evaluating the setups use for in vitro irradiations experiments. Materials and methods: The setup is a water phantom suitable for in vitro research with multiple irradiation modalities, in particular the pencil scanning proton beam available from a horizontal experimental beamline. The phantom included a water tank of 39.0 × 17.0 × 20.5 cm. Cell survival-curves were produced using the cell line V79 Chinese hamster lung fibroblast cells (V79s) in biological triplicates of clonogenic assays. Cell survival curves were produced with both a 18 MeV electron beam, 6 MV photon beam, and a Spread-Out Bragg Peak (SOBP) proton beam formed by pristine energies of 85–111 MeV where three positions were examined. Results: Survival curves with uncertainty areas were made for all modalities. Dosimetric uncertainty amounted to, respectively, 4%, 3% and 3% for proton, electron, and high energy photon irradiations. Cell survival fraction uncertainty was depicted as the standard deviation between replications of the experiment. Conclusion: Cell survival curves could be produced with acceptable uncertainties using this novel water phantom and cellular laboratory workflow. The setup is useful for future in vitro irradiation experiments.
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François, Sabine, Benoit Usunier, Luc Douay, Marc Benderitter e Alain Chapel. "Long-Term Quantitative Biodistribution and Side Effects of Human Mesenchymal Stem Cells (hMSCs) Engraftment in NOD/SCID Mice following Irradiation". Stem Cells International 2014 (2014): 1–13. http://dx.doi.org/10.1155/2014/939275.
Abstract (sommario):
There is little information on the fate of infused mesenchymal stem cells (MSCs) and long-term side effects after irradiation exposure. We addressed these questions using human MSCs (hMSCs) intravenously infused to nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice submitted to total body irradiation (TBI) or local irradiation (abdominal or leg irradiation). The animals were sacrificed 3 to 120 days after irradiation and the quantitative and spatial distribution of hMSCs were studied by polymerase chain reaction (PCR). Following their infusion into nonirradiated animals, hMSCs homed to various tissues. Engraftment depended on the dose of irradiation and the area exposed. Total body irradiation induced an increased hMSC engraftment level compared to nonirradiated mice, while local irradiations increased hMSC engraftment locally in the area of irradiation. Long-term engraftment of systemically administered hMSCs in NOD/SCID mice increased significantly in response to tissue injuries produced by local or total body irradiation until 2 weeks then slowly decreased depending on organs and the configuration of irradiation. In all cases, no tissue abnormality or abnormal hMSCs proliferation was observed at 120 days after irradiation. This work supports the safe and efficient use of MSCs by injection as an alternative approach in the short- and long-term treatment of severe complications after radiotherapy for patients refractory to conventional treatments.
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Hofbauer, Josefina Pinon, Claudia Holler, Ursula Denk, Daniela Asslaber, Gerd Fastner, Verena Labi, Andreas Villunger, Richard Greil e Alexander Egle. "Deletion of Puma and p21Waf1 In Mice Deactivates p53-Induced Cell Death and Cell Cycle Arrest, but Protects Mice From Irradiation-Induced Lymphomagenesis by a Mechanism Involving Hemopoietic Stem Cell Quiescence". Blood 116, n. 21 (19 novembre 2010): 90. http://dx.doi.org/10.1182/blood.v116.21.90.90.
Abstract (sommario):
Abstract Abstract 90 Introduction: The p53 gene is non-functional in >50% of human tumors. In mice deletion of p53 leads to a high incidence of tumors and to a significant acceleration of tumorigenesis induced by repeated gamma-irradiation. While a large number of effects have been described for p53, current concepts of p53-mediated tumor suppression discuss the roles of p53 in regulation of cell cycle and apoptosis as being essential. Two main targets have been identified in this respect: p21Waf1 as an essential regulator of cell cycle arrest downstream of p53 and Puma as the largest single contribution towards p53 induced cell death. Methods: We have generated p21Waf1/Puma doubly deficient (i.e. double-knockout – DKO) mice on a pure C57BL/6 background to investigate the effects on tumorigenesis. Results: In ex vivo irradiation studies DKO thymocytes expectedly showed reduced cell death and loss of a G1/S arrest upon irradiation. When following a cohort of mice for spontaneous tumor development, the DKO mice did not differ from wild-type (WT) controls. Since this may be explained by additional p53 down-stream effectors essential for tumor suppression, we set out to challenge the mice with an established repeated irradiation protocol (4 × 1.75 Gy over 4 weeks) in order to increase the likelihood of uncovering a defect in tumor suppression not apparent in unchallenged mice. While irradiated WT mice developed thymic lymphomas at an expected rate and p53 deficiency accelerated the lymphoma formation as published, irradiated DKO mice did not develop any thymic lymphoma at all. During the irradiation protocol WT mice followed a series of depletion and regrowth cycles in thymic cellularity with a high rate of cell death early post irradiations in TUNEL assays and a surge of proliferation on day 5 after irradiations detected by in vivo BrdU labeling. By contrast in DKO mice thymic cellularity dropped only slightly during the first irradiation cycle. This was followed by a slow and steady decline in cellularity over the following 3 cycles of irradiation. No late apoptotic wave or loss of proliferative capacity of remaining thymocytes could explain the loss of cellularity, nor could senescence of thymocytes be detected by SA-β-Gal staining in situ, suggesting that thymic influx was defective. It had previously been reported for the repeat-irradiation lymphomagenesis model, that the irradiation of hemopoietic precursor cells was essential for tumorigenesis. In contrast to thymic cellularity, DKO LSK numbers stayed relatively stable over the course of the 4 irradiations. By comparison WT LSK numbers dropped to about 50% by the time 4 irradiations were completed. Indeed, short-term repopulating (ST) cells dropped significantly, while long-term repopulating (LT) and multipotent progenitor (MPP) cell populations stayed more stable. In DKO marrows the relative content of LT, ST and MPP cells proved very stable across the irradiation schedule. In vivo BrdU labelling showed that WT LSK had a higher fraction of labelled cells at baseline and a >100% increase in the proliferative fraction during irradiation, while in DKO LSK the proliferation index was lower and stayed stably low over time, compatible with the replenishment defect observed in the thymus. DKO stem cells were only slightly more efficient (1.6-fold) than WT in bone marrow reconstitution experiments without challenge. However, when mixed chimeras were then subjected to the irradiation protocol with 4 × 1.75 Gy a clear advantage of the DKO cells became apparent (28-fold). Moreover, when reconstituting lethally irradiated mice with a mixture of WT and DKO marrow taken from repeatedly irradiated donors the efficacy ratio was 1:152. Conclusion: Our data contrast observations made in cell lines, where loss of Puma and p21Waf1 led to a p53-resistant outgrowth of cells. We present in an animal model that loss of Puma and p21Waf1 is not tumorigenic and in fact protects mice from irradiation carcinogenesis. Together with our recently published findings in irradiated Puma singly-deficient mice (Labi G&D 2010), our data suggest that tumorigenesis in irradiated DKO mice is inhibited by effects on hemopoietic stem cell reactivity to DNA damage. A combination of lack of generation of free niche space through protection of hemopoietic stem cells from cell death and a stem cell quiescence state retained in DKO stem cells after irradiation seems responsible for the phenotype. Disclosures: No relevant conflicts of interest to declare.
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Abdullah, Yusof, Anati Syahirah Hedzir, Nurul Fadzlin Hasbullah, Norasmahan Muridan, Cik Rohaida Che Hak e Sarimah Mahat. "Radiation Damage Study of Electrical Properties in GaN LEDs Diode after Electron Irradiation". Materials Science Forum 888 (marzo 2017): 348–52. http://dx.doi.org/10.4028/www.scientific.net/msf.888.348.
Abstract (sommario):
Nitride-based light emitting diodes (LEDs) is an attractive material due to its high temperature tolerance and suitable to be used in extreme environment. The irradiation process of Gallium Nitride (GaN) diode was carried out by electron irradiation with 1000 kGy and 1500 kGy doses with a conveyor speed of 50 kGy per pass. Capacitance-voltage (C-V) and current-voltage (I-V) characterization for both pre and post irradiation samples was done. Both current and capacitance show decreasing while reverse leakage current increased after irradiation. The reverse leakage current revealed that the current were start leakage at 1.0 x10 -7 A and 1.0 x10-9 A for 1000 kGy and 1500 kGy irradiations respectively. The current-voltage graph indicated that the effect of electron irradiation on diode produced weak spots as defect cause leakage current. The traps and bulk defect is believed to contributed to the leakage current increased.
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Eridon, James, Gary S. Was e Lynn Rehn. "A thermodynamic and kinetic basis for understanding metastable phase formation during ion-beam mixing of nickel-aluminum alloys". Journal of Materials Research 3, n. 4 (agosto 1988): 626–39. http://dx.doi.org/10.1557/jmr.1988.0626.
Abstract (sommario):
A quantitative thermodynamic explanation for the formation of metastable phases in the nickel-aluminum alloy system through heavy-ion irradiation is presented. The role of kinetics in the transformation to a metastable state is also investigated. Experiments involved the irradiation of both layered nickel-aluminum samples and ordered intermetallic compounds with 500 keV krypton ions over a range of temperatures and compositions. Samples were formed by alternate evaporation of layers of nickel and aluminum. A portion of these samples was subsequently annealed to form intermetallic compounds. Irradiations were performed at both room temperature and 80 K using the 2 MV ion accelerator at Argonne National Laboratory. Phase transformations were observed during both in situ irradiations in the high-voltage electron microscope at Argonne and also in subsequent electron diffraction analyses of an array of irradiated samples. Metastable phases formed included disordered crystalline structures, an amorphous structure, and a hexagonal-close-packed structure. These phase structures were modeled using the embedded atom method to compute heats of transformation ΔHs–ms from stable to metastablestates. It was found that metastable states that have moderate heats of transformation, ΔHs–ms ≍ 15%–20% of the heat of formation of the stable phase, form under irradiation. Metastable states with high heats of transformation, ΔHs–ms ≍ 50% of the heat of formation of the stable phase, do not form under irradiation. Kinetics also play an important role in determining the effect of temperature and initial structure on the formation of metastable phases.
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Kinoshita, Hisao, Benfu Hu e H. Takahashi. "Effect of Helium and Aging Treatment on Radiation Damage Behavior in Low Activation Fe-Cr-Mn (W, V) Alloy". Materials Science Forum 475-479 (gennaio 2005): 1455–58. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.1455.
Abstract (sommario):
The effects of helium and aging treatment on radiation damage behavior in low activation Fe-Cr-Mn ( W, V) alloy were investigated by electron and helium ion dual-beam irradiation in a high voltage electron microscope. Specimens were aged at 673 K, 823 K and 923 K for 1000, 3000 and 10000 hours. Electron and He ion dual-beam irradiations were performed at 627 K to 10 dpa. M23C6 type carbides were precipitated in the aged specimens, and the amount of the precipitates was increased with increasing aging temperature and aging time. He bubbles were formed during dual-beam irradiation in all of the specimens. The cavity swelling under dual-beam irradiations was increased with increasing the aging temperature and aging time. It was suggested that cavity swelling is closely related to the concentration of solutes such as Cr and C in the matrix, namely cavity growth rate becomes higher with decreasing of the solutes in solution.
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KIM, BANG-HYUN, AERA JANG, SANG O. LEE, JOONG S. MIN e MOOHA LEE. "Combined Effect of Electron-Beam (beta) Irradiation and Organic Acids on Shelf Life of Pork Loins during Cold Storage". Journal of Food Protection 67, n. 1 (1 gennaio 2004): 168–71. http://dx.doi.org/10.4315/0362-028x-67.1.168.
Abstract (sommario):
The combined effects of organic acids and irradiation on shelf life of pork loins were examined. Fresh pork loins were sprayed with organic acids (lactic, citric, and acetic) at 2%, packaged aerobically, and irradiated with an electron beam at 1, 2, and 3 kGy. During 14 days of storage, total plate count, coliform number, pH, and thiobarbituric acid–reactive substances were measured. Combinations of organic acid and irradiation were more effective in reducing and maintaining low total plate counts and coliform levels during storage than either treatment alone. Higher lipid oxidations were observed in all combination treatments at 1 day of storage than in the irradiation-only group. However, lower lipid oxidations were the result after 14 days of storage when combination treatments were used with irradiations of 2 and 3 kGy. Combined treatments involving lower irradiation doses than those required for irradiation alone could be used to extend the shelf life of pork loins during postirradiation storage without increasing lipid oxidation.
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Mei, Xian Xiu, Jian Qiang Fu, Xiao Fei Liu, Jun Xu e You Nian Wang. "The Corrosion and Oxidation Resistance Improvement of DZ4 Ni-Based Superalloy Irradiated by High Intensity Pulsed Ion Beams". Advanced Materials Research 538-541 (giugno 2012): 276–80. http://dx.doi.org/10.4028/www.scientific.net/amr.538-541.276.
Abstract (sommario):
In this paper, the DZ4 Ni-based superalloy was irradiated by high intensity pulsed C ion and H ion beam. The parameters of ion beam were: accelerating voltage 250 kV, pulse duration 70 ns, ion current density 160 A/cm2. Irradiation pulses were 2, 5, 10 and 15. The morphology of DZ4 before and after irradiation was observed by scanning electron microscope (SEM). The phase structure and stress state were analyzed by X-ray diffraction (XRD). The results show that there were some craters on the surface of the sample after irradiation, as the irradiation time increased, the crater boundary became blurred and even disappeared. The surface tensile stress produced by initial irradiation could be relieved after several irradiations pulses. The corrosion resistance of irradiated DZ4 alloy was improved greatly. The continuous and dense α-Al2O3 layer that formed on irradiated DZ4 surface at 1000°C atmosphere increased the high temperature oxidation resistance.
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Kumar, Piyush, Manuel Belanche, Natalija Für, Luka Guzenko, Judith Woerle, Marianne Etzelmüller Bathen e Ulrike Grossner. "Energy-Dependent Impact of Proton Irradiation on 4H-SiC Schottky Diodes". Materials Science Forum 1092 (6 giugno 2023): 187–92. http://dx.doi.org/10.4028/p-0y444y.
Abstract (sommario):
In this work, the impact of 200 MeV proton irradiation at a fluence of 6 × 1012 cm−2 on the forward characteristics and the breakdown behaviour of nickel (Ni) and titanium (Ti) Schottky barrier diodes is explored. An improvement in the ideality factor, reduction in the threshold voltage, and an increase in the breakdown voltage is observed post irradiation. Point defects induced by the irradiation are likely responsible for the observed effects. Deep Level transient Spectroscopy (DLTS) measurements were performed on the irradiated Schottky diodes to analyse the defects created during the irradiation and gauge their potential role in changing the diode behavior. The defects induced by the high-energy protons were compared to those formed by low-energy proton irradiation at 1.8 MeV to a fluence of 1 × 1012 cm−2. Finally, consecutive DLTS measurements were performed after a series of reverse bias anneals at low temperatures from 350-700 K to explore the annealing behaviour of the defects induced by the proton irradiations.