Action Of Ion Beam Research Articles

Carbon ion irradiation combined with PD-1 inhibitor trigger abscopal effect in Lewis lung cancer via a threshold dose.

Background and goal: Carbon ion beam is radio-biologically more efficient than photons and is beneficial for treating radio-resistant tumors. Several animal experiments with tumor-bearing suggest that carbon ion beam irradiation in combination with immunotherapy yields better results, especially in controlling distant metastases. This implies that carbon ion induces a different anti-tumor immune response than photon beam. More complex molecular mechanisms need to be uncovered. This in vivo and in vitro experiment was carried out in order to examine the radio-immune effects and the mechanism of action of carbon ion beam versus X-ray in combination with PD-1 inhibitors. Methods and Materials: Lewis lung adenocarcinoma cells and C57BL/6 mice were used to create a tumor-bearing mouse model, with the non-irradiated tumor growing on the right hind leg and the irradiated tumor on the left rear. 10Gy carbon ion beam or X-ray radiation, either alone or in combination with PD-1 inhibitor, were used to treat the left back tumor. The expression of molecules linked to immunogenicity and the infiltration of CD8+ T lymphocytes into tumor tissues were both identified using immunohistochemistry. IFN-β in mouse serum was measured using an ELISA, while CD8+ T cells in mouse peripheral blood were measured using flow cytometry. Lewis cells were exposed to different dose of X-ray and carbon ion. TREX1, PD-L1, and IFN-β alterations in mRNA and protein levels were identified using Western blot or RT-PCR, respectively. TREX1 knockdown was created by siRNA transfection and exposed to various radiations. Using the CCK8 test, EdU assay, and flow cytometry, changes in cell viability, proliferation, and apoptosis rate were discovered. Results: Bilateral tumors were significantly inhibited by the use of carbon ion or X-ray in combination with PD-1, particularly to non-irradiated tumor(p<0.05). The percentage of infiltrating CD8+ T cells and the level of IFN-β expression were both raised by 10Gy carbon ion irradiation in the irradiated side tumor, although PD-L1 and TREX1 expression levels were also elevated. Lewis cell in vitro experiment further demonstrated that both X-ray and carbon ion irradiation can up-regulate the expression levels of PD-L1 and TREX1 with dose-dependent in tumors, particularly the trend of up-regulation TREX1 is more apparent at a higher dose in carbon ion, i.e. 8 or 10Gy, while the level of IFN-β is decreased. IFN-β levels were considerably raised under hypofractionated doses of carbon ion radiation by gene silencing TREX1. Conclusions: By enhancing tumor immunogenicity and increasing CD8+T infiltration in TME through a threshold dosage, X-ray or carbon ion radiation and PD-1 inhibitors improve anti-tumor activity and cause abscopal effect in Lewis lung adenocarcinoma-bearing mice. TREX1 is a possible therapeutic target and prognostic marker.

Features of thermal processes and the influence of pulsed heating of surface layers of titanium on the diffusion transfer of dopants during high-intensity ion implantation

Methods for modification of surface and near-surface layers of materials and coatings by ion beamshave prospects for application in many fields of science and technology. The method of high-intensityimplantation by high-power density ion beams with submillisecond duration involves significantpulsed heating of the irradiated target’s surface layer, followed by its rapid cooling due to heatremoval into the material due to thermal conductivity and the implementation of repetitively-pulsedradiation-enhanced diffusion of atoms to depths significantly exceeding the projective ion range. Thispaper considers features of thermal processes and the effect of pulsed heating of near-surface titaniumlayers on diffusion transfer under conditions of synergy of high-intensity titanium ion implantationand energy impact of a high-power density repetitively-pulsed beam on the surface to increase iondoping depth due to radiation-enhanced diffusion under conditions of limited heating of the entiresample. The paper presents the data of numerical simulation of dynamic changes in temperature fieldsin titanium and titanium self-diffusion under the action of ion beams with a submillisecond durationand a pulse power of tens of kW/cm2 and fluence of ions in a pulse 1.25×1015 ion/cm2.

Изменение электронной структуры ориентированных многослойных углеродных нанотрубок при воздействии импульсного ионного пучка наносекундной длительности

Изменение электронной структуры ориентированных многослойных углеродных нанотрубок при воздействии импульсного ионного пучка наносекундной длительности

Effects of Ion Irradiation on Seedlings Growth Monitored by Ultraweak Delayed Luminescence.

The optical technique based on the measurement of delayed luminescence emitted from the biological samples has demonstrated its ability to provide valid and predictive information on the functional status of various biological systems. We want to extend this technique to study the effect of ionizing radiation on biological systems. In particular we are interested in the action of ion beams, used for therapeutic purposes or to increase the biological diversity. In general, the assessment of the damage that radiation produces both in the target objects and in the surrounding tissues, requires considerable time because is based on biochemical analysis or on the examination of the evolution of the irradiated systems. The delayed luminescence technique could help to simplify this investigation. We have so started our studies performing irradiations of some relatively simple vegetable models. In this paper we report results obtained from mung bean (Vigna radiata) seeds submitted to a 12C ion beam at the energy of 62 MeV/nucleon. The dry seeds were irradiated at doses from 50 to 7000 Gy. The photoinduced delayed luminescence of each seed before and after ion irradiation was measured. The growth of seedlings after irradiation was compared with that of untreated seeds. A growth reduction on increasing the dose was registered. The results show strong correlations between the ion irradiation dose, seeds growth and delayed luminescence intensity. In particular, the delayed luminescence intensity is correlated by a logistic function to the seedlings elongation and, after performing a suitable measurement campaign based on blind tests, it could become a tool able to predict the growth of seeds after ion irradiation. Moreover these results demonstrate that measurements of delayed luminescence could be used as a fast and non-invasive technique to check the effects of ion beams on relatively simple biological systems.

Surface modification of polycrystalline oxides (V2O5, MoO3, and WO3) irradiated with high-power ion beams

The influence of a high-power ion beam on polycrystalline oxides (V2O5, MoO3, and WO3) is investigated. Oxide irradiation with ion beams with current densities of greater than ∼30 A/cm2 is established to initiate changes in the color of irradiated layers and lead to surface-layer particle melting. It is demonstrated that a distinctive feature of the interaction between a high-power ion beam and V2O5 is the formation of surface nanosheets and nanowires whose characteristic cross-sectional size and thickness are ∼1 μm and up to ∼40 nm, respectively. The nanosheets are generated near emerging surface cracks if the beam current density is ∼100 A/cm2. Possible mechanisms of surface nanostructures formation under the action of pulsed ion beams are discussed.

Modeling of carbon penetration into silicon structure under the action of pulsed high-intensity ion beam

Abstract The action of high-intensity beam of carbon ions on a silicon sample is studied by means of a numerical modelling revealing formation of the in-depth carbon concentration profile in crystal lattice of silicon. We investigated three ways of the profile forming: short-pulsed ion implantation, recoil atoms mechanism and thermal diffusion of the carbon atoms adsorbed on the silicon surface. The latter is the result of high temperature gradient associated with the action of pulsed high-intensity ion beam. It is argued that the diffusion process plays the major role in forming of the concentration profile in the pre-surface layer of a silicon sample.

The formation of nanostructured carbon material on a ferrocene-containing polymer surface induced by a high-power ion beam

The surface morphology and the composition of polymer layers based on chlorinated polyvinylchloride with addition of ferrocene (up to 10% of the polymer mass) subject to the action of a nanosecond high-power ion beam are studied. It is demonstrated that carbon material in the form of nanofibers with an average diameter of 80 nm and a length of up to 10 μm is formed on a surface singly irradiated by such beam with a current density of ∼100 A/cm2. A possible mechanism of the observed phenomenon is discussed.

Carbon saturation of silicon target under the action of pulsed high-intensity ion beam

The action of the pulsed high-intensity ion (carbon) beam on the silicon target is investigated by means of the theoretical model. The forming of the carbon concentration profile in depth of the silicon sample is modelled. It is argued, that there are two ways of the profile forming: short-pulsed ion (carbon) implantation and diffusion of the carbon atoms adsorbed on the silicon surface. It is shown, that the carbon atoms adsorbed on the silicon surface and diffused into the silicon target play the main role in the concentration profile forming.

The change in optical and electrical characteristics of tin oxide films under the action of argon ion beam

Thin films of tin oxide (TO) were deposited on the glass substrates at room temperature using reactive magnetron sputtering at various oxygen partial pressures. After the deposition the filmswere irradiated with argon ions beam. The change of the optical and electrical properties of the films depending on the irradiation time was studied. Films optical properties in the range of 300-1100 nm were investigated by photometry as well as their structural properties were studied using X-ray diffraction. Diffractometric research showed that the films, deposited on a substrate, have a crystal structure, and after argon ions irradiation they become quasi-crystalline (amorphous). It was found that the transmission increases proportionally with the irradiation time, but the surface resistance -disproportionally.

Generation of Mechanical Waves in Metals under the High Power Ion Beam Irradiation

The system model «high power ion beam – metal» is suggested. Regularities of impulse formation of mechanical load in the volume of metal target subjected to the action of ion beams of different component composition in the range of power density 107...1010 W/cm2 have been considered. The influence of generation mechanisms on the profile and amplitude-to-time parameters of shock-wave excitation is studied.

Modification of polycrystalline SnO2 and ZnO under the action of a high-power ion beam of nanosecond duration

The modification of polycrystalline oxides (SnO2 and ZnO) under the action of a nanosecond high-power ion beam (HPIB) with current densities of 50–150 A/cm2, which is accompanied by melting of initial particles of the surface layer, is investigated. It is established that submicron-sized particles of tetragonal SnO whose average size is 210 nm are formed on the SnO2 surface irradiated by an ion beam with a current density of 150 A/cm2. These particles have pronounced crystallographic faceting. When ZnO is irradiated by HPIBs with different current densities, a thin Zn film is formed in the sintered surface layer. Possible mechanisms of the observed conversions are discussed.

Structural phase transformations in tin dioxide under the action of a nanosecond high-power ion beam

Structural phase transformations in polycrystalline tin dioxide under the action of a nanosecond high-power ion beam with a current density of 50–150 A/cm2 are studied. It is found that the effect of a beam with a current density of 150 A/cm2 on SnO2 leads to the formation of submicron particles of tetragonal SnO with an average size of 210 nm on the exposed surface. The particles have a pronounced crystallographic facet pattern. Possible mechanisms of the observed transformations are discussed.

Numerical study of the phase transitions occurring in metals under the action of pulsed ion beams within the framework of the thermal spike model

Phase transitions occur in materials under the action of high-current high-power beams of charged particles. As a rule, such problems are solved within the framework of the heat-conduction equation. In this paper, studies of phase transitions are carried out within the framework of the thermal spike model, and both models are analyzed and compared. It is established that taking the electron gas into account significantly affects the dynamics of the crystal-lattice temperature and the dynamics of the phase transition.

Wavy microstructures formed at the SiO2/Si interface under the action of high-power ion-beam pulses

The formation of wavy microstructures under the action of a nanosecond pulsed high-power ion beam on the surface of single-crystalline silicon covered with intrinsic oxide layers of various thickness has been studied. Morphological features of the observed structures depend on the oxide layer thickness and ion beam current density. Possible mechanisms of formation of these microstructures are considered.

Formation of surface structures on single-crystalline silicon under the action of nanosecond high-power ion beam pulses

We have studied the formation of surface structures on single-crystalline silicon surface under the action of a nanosecond pulsed high-power proton-carbon ion beam. Morphological features of the structures that appear as a result of this processing are described and possible mechanisms of their formation are considered.

Modification of (Ti,Cr)N coatings on a hard alloy under the action of high-power pulsed ion beams

The changes in the phase composition, the microstress value, the size of the coherent scattering region, the hardness, and the coefficient of friction are studied for a (Ti,Cr)N solid solution deposited on the hard alloy T15K6 during its treatment with high-power pulsed ion beams having an energy density of 9–14 J/cm2.

Modification of hard alloy by the action of high power ion beams

Phase composition, sizes of coherent scattering regions, hardness and friction coefficient of WC–TiC–Co hard alloy and “(Ti,Cr)N coating-on-alloy” system treated by high power ion beams (HPIB) are studied. HPIB treatment was carried out with power densities from 4 to 16 J/cm 2. The effect of HPIB pretreatment (4 J/cm 2) before deposition procedure was studied. HPIB action with energy densities of 8–16 J/cm 2 on hard alloy results in partial fusion of tungsten and titanium carbides. The hardness of surface layer increases by two times and wear resistance improves. HPIB action on “coating-on-alloy” system leads to coarsening of (Ti,Cr)N crystallites, partial decomposition of (Ti,Cr)N and precipitation of chromium phase. Preliminary HPIB treatment (4 J/cm 2) followed by HPIB impact (16 J/cm 2) provides best effect on wear-resistance of (Ti,Cr)N solid solution on hard alloy.

Surface structuring of polycrystalline magnesium under the action of high-power ion beam of nanosecond duration

The formation of periodic structures and micro- and nanoparticles on the surface of polycrystalline magnesium under the action of a high-power proton-carbon ion beam of nanosecond duration have been studied. Spatial parameters of the observed structures and dimensions of particles are determined and possible mechanisms of their formation are considered.

Melting of porous silicon under the action of a nanosecond pulsed high-power ion beam

We have studied the melting of porous silicon (por-Si) layers under the action of a nanosecond pulsed high-power proton-carbon ion beam. Dimensions of ellipsoidal silicon particles formed as a result of this processing have been determined. The threshold energy density necessary for the melting of por-Si with a porosity of ∼50% is experimentally evaluated.

Formation of nanoparticles in a thin metal film on a dielectric substrate under the action of a nanosecond pulsed high-power ion beam

We have studied the formation of nanoparticles in a thin metal film-dielectric substrate system under the action of a high-power nanosecond pulsed proton-carbon ion beam. Data on the particles formed from 5-to 60-nm-thick aluminum and nickel films on ST-50 Sitall (glass-ceramic composite) substrates are presented. Possible mechanisms of nanoparticle formation in ion-irradiated metal films on dielectric substrates are considered.