Soft Irradiation Research Articles

Biological Efficacy of Ionizing Radiation Sources on 3D Organotypic Tissue Slices Assessed by Fluorescence Microscopy.

Traditional cell-based radiobiological methods are inadequate for assessing the toxicity of ionizing radiation exposure in relation to the microstructure of the extracellular matrix. Organotypic tissue slices preserve the spatial organization observed in vivo, making the tissue easily accessible for visualization and staining. This study aims to explore the use of fluorescence microscopy of physiologically compatible 3D tissue cultures to assess the effects of ionizing radiation. Organotypic tissue slices were obtained by vibratome, and their mechanical properties were studied. Slices were exposed by two ionizing radiation sources; electron beams (80 Gy and 4 Gy), and soft gamma irradiation (80 Gy and 4 Gy). Two tissue culture protocols were used: the standard (37°C), and hypothermic (30°C) conditions. A qualitative analysis of cell viability in organotypic tissue slices was performed using fluorescent dyes and standard laser confocal microscopy. Biological dosimetry is represented by differentially stained 200-µm thick organotypic tissue sections related to living and dead cells and cell metabolic activity. Our results underscore the ability of fluorescence laser scanning confocal microscopy to rapidly assess the radiobiological effects of ionizing radiation in vitro on 3D organotypic tissue slices.

High-resolution multi-mode electron and ion imaging spectrometer at SXFEL

A new multi-mode electron and ion (MEI) imaging spectrometer with two arms of VMI and COLTRIMS/VMI (velocity map imaging/cold-target recoil-ion momentum spectroscopy) is designed to combine various photoelectron and ion detection modes for experiments at Shanghai soft x-ray free-electron laser (SXFEL) facility. The experiments can be optionally operated either with both ion and electron detection in a coincidence/covariance manner (VMI arm and COLTRIMS/VMI arm), or only photoelectron/photoion is detected with the high-resolution VMI arm. The simulated resolutions for 30–150 eV photoelectrons and 3.3 eV–18.0 eV N+ and N2+ photoions are up to 1.0% and 3.1%–1.0% according to our simulation, respectively. MEI spectrometer is expected to improve the experimental abilities significantly considering the low-repetition rate of the SXFEL and to enable the investigation of a diverse range of atomic and molecular phenomena triggered by soft x-ray free electron laser irradiation.

Photobiomodulation by soft laser irradiation with and without ibuprofen improves success rate of inferior alveolar nerve block using 2% lignocaine with adrenaline in symptomatic irreversible pulpitis of mandibular molar teeth: a double-blind, randomized placebo-controlled trial.

Achieving successful pain control and adequate anesthesia through an inferior alveolar nerve block for endodontic treatment in cases with symptomatic irreversible pulpitis (SIP) is difficult, especially in mandibular molars. This study was designed to compare the effect of oral medication with ibuprofen and soft laser therapy on inferior alveolar nerve block during endodontic treatment. The trial comprised 180 patients (45 each group) with SIP. Four groups of patients were created: group 1 received 400 mg of ibuprofen; group 2 received soft laser irradiation; group 3 received a combination of soft laser and ibuprofen 400 mg; and group 4 received a placebo 1 h prior to local anesthesia. Patients recorded their pain scores on the Heft-Parker visual analog scale (VAS) before the start of intervention, 15 min after anesthesia, during access cavity preparation, and ultimately during root canal instrumentation. Each patient also rated their level of discomfort on a VAS. Every stage with no or minimal discomfort was deemed successful. The chi-square, Kruskal-Wallis, and one-way analysis of variance tests were used to evaluate the data. The best success rate was achieved for soft laser ibuprofen combination, ibuprofen and soft laser groups reported similar success results, and control group recorded the least pain scores. The mean pain scores were lowest for group 3 and highest for group 4 (P < 0.001). Ibuprofen and soft laser combination was significantly better than control group (P < 0.001). There was no significant difference between ibuprofen and laser groups (P = 0.24). For teeth with irreversible pulpitis, preoperative ibuprofen treatment combined with soft laser irradiation greatly improved the success rates of inferior alveolar nerve block anesthesia.

High linear energy transfer (LET) nature of alanine radical yield by soft X-ray irradiations studied by electron spin resonance (ESR) applications

Radicals produced in alanine by irradiation of 2–7 keV X-rays were investigated by ESR applications; i.e., CW-ESR, pulse-ESR and ESR imaging. The relative radical yield decreased with the decreasing photon energy and the increasing dose. The 2D imaging showed that the radical concentration at the surface was extremely low even though the absorption of X-rays exponentially decreased with the penetration depth. The depth of the radical concentration peak was almost the same as the penetration depth for the X-ray irradiation with an energy lower than 5-keV. The product formed by radical recombination was observed by an LC/MS (liquid chromatograph-mass spectrum) analysis. For the soft X-ray irradiation, many radicals will be lost by the efficient radical-radical recombination due to the higher density of the radicals, similar to the high-LET irradiation by heavy ions. The spin-spin relaxation rate (1/T2), which correlates with the radical concentration, increased by the decreasing photon energy. The values of 1/T2 for the soft X-rays were compatible to that for the heavy ions with the high-LET. Based on these observations, it is concluded that the effects of irradiation by soft X-rays are similar to high-LET irradiation.

Sub-nanometer scale depth patterning on sapphire crystal by femtosecond soft x-ray laser pulse irradiation.

Damage thresholds and structures on a metal aluminum and an aluminum oxide crystal induced by the soft x-ray free electron laser irradiations were evaluated. Distinctive differences in damage thresholds and structures were observed for these materials. On the aluminum oxide crystal surface, in particular, a novel, to the best of our knowledge, surface processing, which we suggest defining as "peeling," was recognized. Surface structures formed by peeling had extremely shallow patterning of sub-nanometer depth. For the newly observed peeling process, we proposed a scission of chemical bond, i.e., binding energy model, in the crystal.

Photocatalysis: A Possible Vital Contributor to the Evolution of the Prebiotic Atmosphere and the Warming of the Early Earth

The evolution of the early atmosphere was driven by changes in its chemical composition, which involved the formation of some critical gases. In this study, we demonstrate that nitrous oxide (N2O) can be produced from Miller’s early atmosphere (a mixture of CH4, NH3, H2, and H2O) by way of photocatalysis. Both NH3 and H2O were indispensable for the production of N2O by photocatalysis. Different conditions related to seawater and reaction temperature are also explored. N2O has a strong greenhouse gas effect, which is more able to warm the Earth than other gases and offers a reasonable explanation for the faint young Sun paradox on the early Earth. Moreover, the decomposition of N2O into N2 and O2 can be boosted by soft irradiation, providing a possible and important origin of atmospheric O2 and N2. The occurrence of O2 propelled the evolution of the atmosphere from being fundamentally reducing to oxidizing. This work describes a possible vital contribution of photocatalysis to the evolution of the early atmosphere.

Photopolymerization of Poly(Hydroxyethyl Acrylate) (PHEA): Experimental Parameters-Viscoelastic Properties Relationship

The activity of the photoinitiator system, based on triethanolamine (TEOA) and methylene blue (MB), on the photopolymerization of hydroxyethyl acrylate (HEA) monomer under very soft irradiation conditions, was evaluated. A remarkable difference in the polymerization kinetics of a set of PHEA experiments was underlined according to TEOA/MB concentrations, as well as the solutions pH. Indeed, the complex viscosity (η*), storage modulus (G'), and loss modulus (G") of the resulting polymers were potentially dependent on these experimental parameters despite comparable values of monomer conversion.

Cyanocobalamin (vitamin B12) as insensitive porphyrinoid to solar LED irradiation

Cobalamins are cobalt corrin complexes (vitamin B12) with typical porphyrinoid structure and absorption which partly overlaps with the solar spectrum of irradiation. This highly conjugated structure is assumed to have not only the well-known curative action as co-factor and vitamin, but also phototoxicity on dysfunctional, and, in a low extent, on normal cells. Moreover, the cobalamin can have properties as a photosensitizer at appropriate light conditions. The present study aims at characterization of the cyanocobalamin (CNCbl) as a synthetic cobalamin under solar-spectrum irradiation. The photo- and dark cytotoxicity studies were carried out on a normal cell line (BALB/c 3T3, A31) showing no effect due to light application. The photodynamic action of CNCbl due to its porphyrinoid-like structure was not observed. The results on two breast cancer cell lines (MDA-MB-231 and MCF-7) versus a non-tumorigenic cell line (MCF-10) showed similar values for cytotoxicity. A complete loss of viability was observed at approx. 10-4 M CNCbl after 24-hs incubation and soft irradiation (10 J/cm2) for the spectral range 360-960 nm of a LED Helios-iO solar simulator. The cobalt corrin complex showed non-photodynamic ability to reduce the viability of both breast tumor cells depending on the nature of the cell line but not on the light application.

Повреждаемость поверхностного слоя сплава Инконель 718 импульсными пучково-плазменными потоками

The damage of the surface layer of the Inconel 718 alloy, prepared by additive technology by selective laser melting with subsequent heat treatment, is studied under the conditions of repeated pulsed exposure to flows of helium ions and helium plasma in two modes of irradiation in the Plasma Focus “Vikhr” facility: in soft mode with energy flux density q0 = 2·108 W/cm2 at pulse duration τ = 50 ns and in hard mode (q0 = 1.5·109 W/cm2, τ = 25 ns). The number of pulsed actions in the experiments was N = 10 and 20. Under the implemented conditions of pulsed irradiation, the processes of sputtering and evaporation of the surface layer of the alloy, as well as its melting and crystallization at a high rate, took place. In this case, the original flat surface of the alloy sample was transformed into a wavy relief containing in some areas a thin film wrinkled in the form of ripples. In the soft irradiation regime, the surface microstructure contained pores, while under more severe energy impacts, surface microcracks and blisters with destroyed shells were also observed. With an increase in the energy flux density q, the intensity of surface erosion (mass loss per pulse) increased. The nature of this phenomenon was influenced by the processes of purification of the alloy surface from elements adsorbed from the external environment before irradiation, as well as deposition of elements of functional materials and impurities of the working gas on the irradiated surface. Features of the formation of the cellular microstructure of the surface layer of the investigated alloy under the realized conditions of beam-plasma impacts were revealed. Using numerical simulation, the redistribution of the fractions of the energy absorbed by the material spent on the evaporation and melting of the irradiated surface layer was established in comparable irradiation modes.

Gamma radiation on silver nano colloid for anti-fungal activity

Soft gamma ray irradiation is done on Silver nano colloids prepared using Pepper Nigrum as reducing and stabilizing agent. Change in surface morphology and the structure of the colloid is obtained from Transmission Electron Microscope images and Selected area Electron Diffractogram. Morphology of the gamma irradiated sample is devoid of nano particle clusters and the Selected Area Electron Diffraction pattern confirms the crystal nature as face centered cubic structure of nano silver. UV–visible spectroscopic analysis gives the absorption peaks in the green region. Gamma irradiation results in the reduction in peak intensity without any change in wavelength. A statistical approach is done on treating the gamma irradiated colloidal sample with the as prepared silver nano colloid for measuring the area of affecting fungal infection on a potato-agar medium. It is found that the fungal growth is declined rapidly with the introduction of gamma irradiated silver nano colloid than the as prepared colloid.

Structural and optical studies of colloidal silver nano particles

Colloidal silver nano particles are prepared by biosynthesis using medicinal plants like Ocimum Sanctum and AdhaThodaVasica. Soft gamma ray irradiation is done on the samples. Transmission electron microscopic image of before irradiated silver nano colloid shows the agglomeration of spherical nano clusters while the irradiation results in the reduction of particle size with well defined grains. Selected area electron diffraction studies can explain both the polycrystalline pattern of silver nano colloids. Further, the crystal structure is identified as Face Centered Cubic pattern. The formation and stability of silver nano particles in the colloidal solutions are monitored using uv–visible absorption spectra. Gamma irradiation does not change the band gap value of nano silver. Here the plant extracts served not only as reducing agents but also a good stabilizing agent, which prevents the aggregation of silver nano particles. Gamma ray irradiation helps a better confined morphology for silver nano particle without affecting the structural parameters and optical band gap values.

Influence of ice structure on the soft UV photochemistry of PAHs embedded in solid water

Context. The UV photoreactivity of polycyclic aromatic hydrocarbons (PAHs) in porous amorphous solid water has long been known to form both oxygenated photoproducts and photofragments. Aims. The aim of this study is to examine the influence of ice structure on reactivity under soft UV irradiation conditions. Methods. Mixtures of PAHs with amorphous solid water (porous and compact) and crystalline (cubic and hexagonal) ices were prepared in a high vacuum chamber and irradiated using a mercury lamp for up to 2.5 h. Results. The results show that the production of oxygenated PAHs is efficient only in amorphous water ice, while fragmentation can occur in both amorphous and crystalline ices. We conclude that the reactivity is driven by PAH–water interactions in favourable geometries, notably where dangling bonds are available at the surface of pores. Conclusions. These results suggest that the formation of oxygenated PAH molecules is most likely to occur in interstellar environments with porous (or compact) amorphous solid water and that this reactivity could considerably influence the inventory of aromatics in meteorites.

Laser-induced damage thresholds and mechanism of silica glass induced by ultra-short soft x-ray laser pulse irradiation.

Laser-induced damage thresholds (LIDTs) of silica glasses obtained by the femtosecond soft x-ray free-electron laser (SXFEL, 13.5 nm, 70 fs) and the picosecond soft x-ray laser (SXRL, 13.9 nm, 7 ps) are evaluated. The volume of the hydroxyl group in the silica glasses influenced its LIDTs. The LIDTs obtained in this research by the femtosecond SXFEL and the picosecond SXRL were nearly identical, but were different from that by the nanosecond soft x-ray pulse. The photoionization processes of silica glass in context of the laser-induced damage mechanism (LIDM) are also discussed. In the ultra-short soft x-ray pulse irradiation regime, the LIDM can be speculated to include the spallation process with a scission of bondings.

МЕТОД «МЯГКОГО ОБЛУЧЕНИЯ» ПРИ ИЗБИРАТЕЛЬНОМ РАСТВОРЕНИИ ЗЛОКАЧЕСТВЕННЫХ ОПУХОЛЕЙ В ПРЕДВАРИТЕЛЬНО ОЗОНИРОВАННЫХ РАСТВОРАХ

In the work, the method of "soft irradiation" is presented for selective dissolution of malignant tumors in pre-ozonated solutions. Oncological diseases are one of the main problems of our time that we have encountered. Their occurrence is caused by different factors, such as ecology, the use of lowquality products, toxic compounds and chemicals in water, alcohol, nicotine, drugs, radiation and some viruses. The article describes the main methods of combating malignant tumors at the moment, their negative and positive sides. Such methods as surgical, chemotherapeutic, radiotherapeutic, photodynamic therapy are considered. The work considers an improved method, which can be attributed to a new direction in chemotherapy. Based on the "soft irradiation" method, a series of studies has been carried out, the purpose of which is to develop a methodology for treating tumor cells with the further development of equipment for their selective destruction. The next step is the stage of animal experiments and clinical trials on human organisms, the creation of an industrial clinical model of equipment. This technique can be used in any hospital. Considering the cost and ease of use, this technology will find wide demand among medical institutions. To carry out ozone-radical removal of malignant tumors, medical ozonizer; probes for the in-troduction and withdrawal of working solution; peristaltic pumps for pumping working solution; oxygen cylinder or other oxygen source; ozone saturation reactor; reactor for working solution production are needed. It is necessary to create instruments and apparatus for ozone-surgical exposure; to develop and test the probe systems for supplying reagents and discharging spent solutions.

Photoacoustic effect applied on model membranes and living cells: direct observation with multiphoton excitation microscopy and long-term viability analysis

The photoacoustic effect is generated when a variable light interacts with a strongly light-absorbing material. In water, it may produce hot bubbles and shock waves that could affect the integrity of nearby cellular membranes, opening transient pores (photoporation). In this study, we have evaluated the effect of pulsed laser-irradiated carbon nanoparticles (cNP) on model membranes and on Chinese hamster ovary (CHO) cells. Fluorescence lifetime measurements of calcein-loaded liposomes support the notion that the photoacoustic effect causes transient openings in membranes, allowing diffusion fluxes driven by gradient concentrations. With CHO cells, we have shown that this effect can induce either intracellular delivery of calcein, or release of cellular compounds. The latter process has been recorded live with multiphoton excitation microscopy during pulsed infrared laser irradiation. Calcein loading and cell viability were assayed by flow cytometry, measuring necrotic cells as well as those in early apoptosis. To further assess long-term cell recovery after the rather harsh treatment, cells were reseeded and their behaviour recorded for 48 h. These extended studies on cell viability show that pulsed laser cNP photoporation may be considered an adequate intracellular delivery technique only if employed with soft irradiation conditions (below 50 mJ/cm2).

Treatment of Dentinal Hypersensitivity using desensitizing agents plus soft laser irradiation. A Randomized Comparative Clinical Trial

This study aimed to evaluate the efficacy of diode laser combined with two in-office desensitizing agents 8% Arginine-CaCO3 and 1.23 NaF varnish on reducing dentine hypersensitivity (DH) in periodontitis patients. Materials and Methods: Forty patients having stage I and Stage II periodontitis were selected according to the criteria of AAP (2017) with complaint of (DH) after routine periodontal therapy . Patients were randomly divided into two groups: group1- received NaF varnish then diode laser application at 1 W (PW) ,(CW) for 30 seconds using 320µ fiber. Group-2, treated with 8%Arginine-CaCO3 plus same laser irradiation. Each tooth received three application Dentine hypersensitivity evaluation was by tactile, air-blast, and thermal stimuli and measured using VAS scores. The patient’s response was recorded at baseline, one month and 3 month after the application.Results and conclusions: The results were statistically analyzed, and it was found that 8% Arginine-CaCO3 plus laser treatment was more effective than 1.23% NaF-varnish plus laser at time intervals. Sensitivity score differences between the groups were statistically significant at one and three months. The 8% Arginine-CaCO3 group exhibited statistically significant reduction in dentine hypersensitivity on three stimuli at baseline to one and three months. It was concluded that 8% Arginine- CaCO3 plus laser irradiation is more effective than 1.23% NaF varnish plus laser irradiation in reduction of patients’ pain in periodontitis patients.

Photo‐Tunable Supramolecular Ultrathin Surfaces for Simultaneous Homeotropic Anchoring and Superfast Switching of Liquid Crystals

AbstractPhoto‐tunable supramolecular ultrathin surfaces functionalized with a soft ultraviolet (UV) treatment of star‐shaped reactive amphiphiles are fabricated to simultaneously afford homeotropic anchoring of liquid crystals (LCs) and improve the LC switching performance. Photochemically functionalized ultrathin surfaces are generated by cross‐linking star‐shaped amphiphilic monomers in the self‐assembled monolayers with retention of cluster structure under electric field. Since these star‐shaped amphiphiles can construct the close‐packed self‐organized molecular layer with an alkyl brush at the interface between indium tin oxide and LCs through intermolecular hydrogen bonding, they might make elegant alignment surfaces for the homeotropic anchoring of LCs to provide a new type of vertical alignment layer. It is experimentally revealed that supramolecular ultrathin layers with vertical nanopillars form hydrophobic surface, and afford a stable and uniform homeotropic alignment of LCs even in high‐temperature environment. Furthermore, a soft UV irradiation on the self‐assembled ultrathin surfaces under electric field yields superfast responsive cross‐linked ultrathin surfaces with low power consumption compared to conventional polyimide layer. Notably, this controlled methodology offers advantages of simplicity, low‐cost, and scalability in the fabrication of functional alignment surfaces without the need of complex manufacturing steps.

Development of New High-Performance Biphenyl and Terphenyl Derivatives as Versatile Photoredox Photoinitiating Systems and Their Applications in 3D Printing Photopolymerization Processes

Novel 2-amino-4-methyl-6-phenyl-benzene-1,3-dicarbonitrile derivatives were proposed as photosensitizes of iodonium salt for a highly effective bimolecular photoinitiating system upon soft irradiation conditions under long-wave ultraviolet (UV-A) and visible light. Remarkably, these structures are highly versatile, allowing access to photoinitiating systems for the free-radical polymerization of acrylates, the cationic photopolymerization of epoxides, glycidyl, and vinyl ethers, the synthesis of interpenetrated polymer networks (IPNs) and the thiol-ene photopolymerization processes. Excellent polymerization profiles for all of the monomers, along with the high final conversions, were obtained. The initiation mechanisms of these bimolecular systems based on the 2-amino-4-methyl-6-phenyl-benzene-1,3-dicarbonitrile derivatives were investigated using the real-time FT-IR technique, steady-state photolysis, fluorescence experiments, theoretical calculations of molecular orbitals, and electrochemical analysis. Moreover, the 2-amino-4-methyl-6-phenyl-benzene-1,3-dicarbonitrile derivatives were investigated as a type II free-radical photoinitiator with amine. It was confirmed that the 2-amino-4-methyl-6-phenyl-benzene-1,3-dicarbonitrile derivatives, in combination with different types of additives, e.g., amine as co-initiator or in the presence of onium salt, can act as a bimolecular photoinitiating system via the photo-reduction or photo-oxidation pathways, respectively.

A spectroscopic study to assess the photogeneration of singlet oxygen by graphene oxide

The photogeneration of singlet oxygen (1O2) during short irradiation times of graphene oxide (GO) is assessed under visible light with soft irradiation conditions either directly monitoring the phosphorescence emission of 1O2 at ca. 1275 nm, or indirectly by means of the fluorescent probe 9,10-anthracenediyl-bis(methylene)dimalonic acid (ABDA). Results obtained using both methodologies lead to the conclusion that 1O2 generation is negligible under our experimental conditions. In the case of using ABDA very small emission changes were recorded, which could be attributed to other side reactions. Special care should be taken when using this spectroscopic probe to assess the generation of 1O2, since ABDA and related probes based on the reactivity of the anthracene fluorophore can also detect electron transfer processes. This kind of approaches have been less explored in the field of Materials Science at the nanoscale, and we believe that the knowledge on the lack of generation of 1O2 by irradiated GO is informative and useful, especially for the assessment of the environmental and biological toxicity of nanomaterials based on GO.

Dose Analysis of In Vitro and In Vivo Test for Boron Neutron Capture Therapy (BNCT)

The purpose of this study was to determine the in vitro and in vivo doses of boron neutron capture cancer therapy (BNCT) using the SHIELD-HIT12A program. To be able to determine the recoil energy, the research was conducted using the Monte Carlo method. Running data obtained the value of ionization activity and recoil lost. The results showed that in vitro and in vivo doses of BNCT for soft tissue irradiation had a value of 0.312 × 10-2 Sv, which is safe and does not harm healthy body tissue around the cancer cells because it is below the threshold of 1.5 Rem or 15 × 10-3 Sv, in accordance with the provisions of the upper value permitted by the International Commission on Radiation Protection in 1966. While the comparative targets are water, the optimal target absorption dose was obtained at concentrations of 3.232 × 10-3 Gy. The dose of carbon equivalent in water with the type of thermal neutron radiation was 16.16 × 10-3 Sv; this dose is classified as unsafe.