Irradiation Apparatus Research Articles

Evaluation of Anticancer Activity of Nucleoside-Nitric Oxide Photo-Donor Hybrids.

Herein, we report the synthesis of a new hybrid compound based on a 2'-deoxyuridine nucleoside conjugated with a NO photo-donor moiety (dU-t-NO) via CuAAC click chemistry. Hybrid dU-t-NO, as well as two previously reported 2'-deoxyadenosine based hybrids (dAdo-S-NO and dAdo-t-NO), were evaluated for their cytotoxic and cytostatic activities in selected cancer cell lines. dAdo-S-NO and dAdo-t-NO hybrids displayed higher activity with respect to dU-t-NO. All hybrids showed effective release of NO in the micromolar range. The photochemical behavior of the newly reported hybrid, dU-t-NO, was studied in the RKO colon carcinoma cell line, whereas the dAdo-t-NO hybrid was tested in both colon carcinoma RKO and hepatocarcinoma Hep 3B2.1-7 cell lines to evaluate the potential effect of NO released upon irradiation on cell viability. A customized irradiation apparatus for in vitro experiments was also designed.

Major target for UV-induced complete loss of HIV-1 infectivity: A model study of single-stranded RNA enveloped viruses

Deep ultraviolet light (UV) is useful for the disinfection of microorganisms, including bacteria and viruses. Although genome damage by UV has been widely accepted, the adverse effects of UV on the activity and/or function of viral proteins including the envelope components are poorly documented. Worthy of note, the observed unfavorable UV-effects for viruses are only insufficiently analyzed in association with the reduction in viral infectivity. In this study, we aimed to clarify which component of virions affected by UV significantly correlates with the loss of viral infectivity using HIV-1 as a model for single-stranded RNA enveloped viruses. Using our UV irradiation apparatus at three wavelengths (265, 280, and 300 nm), we first quantitatively determined the UV power density and irradiation period of each wavelength required for a reduction in infectivity. A heat-treated sample as a control drastically reduced the virion-associated reverse transcriptase (RT) activity and Gag-p24 level. The UV-irradiated samples at the three wavelengths, completely lacking viral infectivity, showed p24 levels similar to those without irradiation. While the virion-associated RT activity was gradually decreased in a wavelength and power density dependent manner, this reduction did not explain the loss of viral infectivity by UV. Remarkably, virological assays revealed that the entry efficiency of the UV-irradiated virus samples at the three wavelengths is comparable to those without irradiation. Importantly, this result shows that, even the virions exposed to UV of various wavelengths at the lethal level, still maintain the function of their envelope composed of a host lipid bilayer and viral proteins. In sharp contrast, UV-induced genome damage shown by semiquantitative RT-PCR correlated well with the reduction in viral infectivity, indicating that it is a major determinant for virus inactivation by UV. The degree of damage was found to be distinct among the regions analyzed. This was probably due to the different nucleotide sequences in those genomic regions amplified by PCR. Our data clearly demonstrate a principal mechanism for viral inactivation by UV and provide information contributing to the improvement of UV-based disinfection technology for microorganisms.

Quantitative evaluation of SARS-CoV-2 inactivation using a deep ultraviolet light-emitting diode

Inactivation technology for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is certainly a critical measure to mitigate the spread of coronavirus disease 2019 (COVID-19). A deep ultraviolet light-emitting diode (DUV-LED) would be a promising candidate to inactivate SARS-CoV-2, based on the well-known antiviral effects of DUV on microorganisms and viruses. However, due to variations in the inactivation effects across different viruses, quantitative evaluations of the inactivation profile of SARS-CoV-2 by DUV-LED irradiation need to be performed. In the present study, we quantify the irradiation dose of DUV-LED necessary to inactivate SARS-CoV-2. For this purpose, we determined the culture media suitable for the irradiation of SARS-CoV-2 and optimized the irradiation apparatus using commercially available DUV-LEDs that operate at a center wavelength of 265, 280, or 300 nm. Under these conditions, we successfully analyzed the relationship between SARS-CoV-2 infectivity and the irradiation dose of the DUV-LEDs at each wavelength without irrelevant biological effects. In conclusion, total doses of 1.8 mJ/cm2 for 265 nm, 3.0 mJ/cm2 for 280 nm, and 23 mJ/cm2 for 300 nm are required to inactivate 99.9% of SARS-CoV-2. Our results provide quantitative antiviral effects of DUV irradiation on SARS-CoV-2, serving as basic knowledge of inactivation technologies against SARS-CoV-2.

О возможностях реабилитации больных хроническими дерматозами и заболеваниями половой сферы в условиях Юга Украины – Херсонская область

The article provides an example of the effective introduction of comprehensive rehabilitation therapy for patients with common and severe skin diseases (psoriasis, atopic dermatitis, eczema, lichen planus, and others), arthropathy of various origins and diseases of the genital area. The Center has been operating since 2018 as a subdivision of the Kherson Regional Skin and Venereal Diseases Dispensary of the Kherson Regional Council of Kherson, and later on, the public organization «Kherson Psoriasis Association» opened the «Aquaderm» Dermatological Center here. Materials and methods. The center is provided with modern equipment (3 types of bathtubs – Chirana, hydromassage, whirlpool; ultraviolet irradiation apparatus «Psorolight 100-6»). Physiotherapeutic procedures are used, consisting in the treatment with mineral waters, as well as with the therapeutic mud of Lake Solyanoye(Kherson region). Light therapy and climatotherapy are used. Patients undergo a set of laboratory tests before prescribing therapy and during treatment. Discussion of the findings. The data on the treatment of patients at the «Aquaderm» institution in 2018–2019 and the first half of 2020 are presented. A total of 5551 patients were treated during the reporting period and 164601 physiotherapeutic procedures were performed, what indicate that the types of rehabilitation treatment used are effective. The center attracts patients from different regions of Ukraine and enjoys the support of the Kherson Regional State Administration.

Nitridation Reaction of Titanium Powders by 2.45 GHz Multimode Microwave Irradiation using a SiC Susceptor in Atmospheric Conditions

A titanium nitride (TiN) coating using microwaves can be accomplished in air, and satisfies the required conditions of an on-demand TiN coating process. However, the coating mechanism using microwaves is not completely clear. In this study, to understand the detailed mechanism of microwave titanium nitridation in air, the quantity of nitrogen and oxygen in reacted TiN powder has been investigated by an inert melting method. Titanium powders were irradiated with microwaves by a multi-mode type 2.45 GHz microwave irradiation apparatus, while also being held at various temperatures for two different dwell times. X-ray diffraction (XRD) results revealed that nitridation of the powder progressed with increasing process temperature, and the nitridation corresponds to the powder color after microwave irradiation. The nitrogen contents of the samples increased with increasing processing temperature and dwell time, unlike oxygen. It is postulated that the reaction of convected air with titanium is a key role to control nitridation in this system.

754 Near-infrared light 790-1000 nm causes photoaging in vivo and in vitro

Objective: Near-infrared radiation (NIR), which is a composition of sunlight with a 700-2000 nm wavelength, is associated with skin aging such as wrinkles and slacks. On the other hand, NIR irradiation is effective for the improvement of skin photo damage. In the present study, we examined the effect of NIR on the skin in vivo and in vitro using a NIR irradiation apparatus that controls wave length and irradiation dose. Methods: The NIR irradiation apparatus has a halogen flash lamp where the light is white similar to sunlight (790-1700 nm). The skin of hamsters or mice was irradiated every other day for 1.75-7 min with NIR (190 mW/cm2). After fixing skin tissues at 1, 3, and 5 days post-irradiation, hematoxylin-eosin and immunohistochemical staining and the measurement of intracutaneous temperature were performed. The expression of reactive oxygen species (ROS) and inflammatory cytokines was analyzed in NIR-irradiated human epidermal keratinocytes (HEK). Results: NIR irradiation with 780-1700 nm caused epidermal thickness, sebaceous hyperplasia, and the augmentation of matrix metalloproteinase 1 (MMP-1) expression in the auricle skin of the hamsters. In addition, the intracutaneous temperature was increased up to 47 oC. Furthermore, the increase of ROS and TNF-α production was detectable in the NIR-irradiated HEK. However, neither said histological alteration nor the increase of MMP-1, intracutaneous temperature, ROS, and TNF-α was detectable in a filter-selected NIR (>1000 nm) irradiated skin and HEK. Conclusion: These results provide novel evidence that NIR with 790-1000 nm wavelength causes photoaging actions such as epidermal thickness, sebaceous hyperplasia, and the augmentation of MMP and TNF-α production in epidermis in vivo, which are closely associated with an increase in intracutaneous temperature and ROS levels.

Initiator‐free photopolymerization of common acrylate monomers with 254 nm light

AbstractUsing an available light source at a wavelength of 254 nm, common acrylate monomers were polymerized without any photoinitiators, which was confirmed using Fourier transform IR (FTIR) spectroscopy, 1H NMR, gel permeation chromatography and fast atom bombardment mass spectrometric measurements. It was found that phenyl acrylate shows higher conversion than n‐ and t‐butyl acrylates. A trifunctional acrylate was also used for UV curing. The cured films were fabricated successfully on different kinds of substrates by using a batch‐ or conveyor‐type irradiation apparatus. It is indicated from FTIR spectral measurements that ca 40%–50% of acryloyl groups are consumed by the photopolymerization. Oxygen concentration in the sample chamber influences the photopolymerization, indicating that the polymerization proceeds via a radical process. © 2018 Society of Chemical Industry

A new apparatus for on-site calibration of gamma dose rate monitors.

In order to carry out on-site calibrations of environmental gamma dose rate monitors, a new irradiation apparatus was developed in this study. The apparatus mainly consists of a piece of 137Cs source, a set of beam attenuators, and 3 built-in laser rangefinders, and it can be remotely controlled by using a laptop through WiFi network. With an activity of 4.6 × 108 Bq of 137Cs source, the reference air kerma rate could be adjusted from 0.26 μGy h-1 to 140 μGy h-1 by changing the calibration distance from 0.5 m to 5 m and using different beam attenuators (or none), and both the reproducibility and the homogeneity of reference radiation were better than 97%. The overall uncertainty of the calibration was estimated to be 6.5% (k = 2). Both the laboratory and field experiments confirmed that the calibration method met the requirements of ISO 4037-1. As the advantages of portability and simplicity, it is considered that the new irradiation apparatus is applicable to stationary gamma radiation monitors for on-site calibration.

Study on Clarification of Large-Area EB Irradiation Phenomenon by Electron Track Analysis

In large-area electron beam (EB) irradiation method, uniformly high energy density can be obtained without focusing the beam. Large-area EB can be used for melting and evaporating metal surface instantly. It was clarified that high efficient surface finishing of metal mold steels, ceramics and cemented carbides was possible by the large-area EB irradiation. Furthermore, the tip of convex shape was often rounded after large-area EB irradiation with remarkable material removal at the tip. This phenomenon is probably caused due to the heat accumulation and electrons concentration at the tip. However, electrons behavior near the workpiece surface during large-area EB irradiation has not yet been clarified. In this study, electron track analysis was conducted in order to clarify electrons behavior during large-area EB irradiation. At first, analytical model of the large-area EB irradiation apparatus was built. Then, the EB diameter on the workpiece surface was experimentally measured with different energy density in order to evaluate the accuracy of our analytical model. The calculated results of EB diameter were in good agreement with the experimental ones. In addition, the electrons concentration phenomenon at the tip of convex shape was clarified by calculating energy density distribution on the surface obtained with electron track analysis. The analytical results indicated that the energy density increased from edge to tip of convex shape, while the energy density was constant in the case of planar shape. Experimented results also showed that removal thickness increases with high relative permeability. These results were similar tendency to the energy density distribution. Therefore, electrons concentration on the tip could be simulated by the electron track analysis.

Electron linear accelerator system for natural rubber vulcanization

Development of an electron accelerator system, beam diagnostic instruments, an irradiation apparatus and electron beam processing methodology for natural rubber vulcanization is underway at the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The project is carried out with the aims to improve the qualities of natural rubber products. The system consists of a DC thermionic electron gun, 5-cell standing-wave radio-frequency (RF) linear accelerator (linac) with side-coupling cavities and an electron beam irradiation apparatus. This system is used to produce electron beams with an adjustable energy between 0.5 and 4MeV and a pulse current of 10–100mA at a pulse repetition rate of 20–400Hz. An average absorbed dose between 160 and 640Gy is expected to be archived for 4MeV electron beam when the accelerator is operated at 400Hz. The research activities focus firstly on assembling of the accelerator system, study on accelerator properties and electron beam dynamic simulations. The resonant frequency of the RF linac in π/2 operating mode is 2996.82MHz for the operating temperature of 35°C. The beam dynamic simulations were conducted by using the code ASTRA. Simulation results suggest that electron beams with an average energy of 4.002MeV can be obtained when the linac accelerating gradient is 41.7MV/m. The rms transverse beam size and normalized rms transverse emittance at the linac exit are 0.91mm and 10.48πmm·mrad, respectively. This information can then be used as the input data for Monte Carlo simulations to estimate the electron beam penetration depth and dose distribution in the natural rubber latex. The study results from this research will be used to define optimal conditions for natural rubber vulcanization with different electron beam energies and doses. This is very useful for development of future practical industrial accelerator units.

Temperature measurements during high flux ion beam irradiations.

A systematic study of the ion beam heating effect was performed in a temperature range of -170 to 900 °C using a 10 MeV Au(3+) ion beam and a Yttria stabilized Zirconia (YSZ) sample at a flux of 5.5 × 10(12) cm(-2) s(-1). Different geometric configurations of beam, sample, thermocouple positioning, and sample holder were compared to understand the heat/charge transport mechanisms responsible for the observed temperature increase. The beam heating exhibited a strong dependence on the background (initial) sample temperature with the largest temperature increases occurring at cryogenic temperatures and decreasing with increasing temperature. Comparison with numerical calculations suggests that the observed heating effect is, in reality, a predominantly electronic effect and the true temperature rise is small. A simple model was developed to explain this electronic effect in terms of an electrostatic potential that forms during ion irradiation. Such an artificial beam heating effect is potentially problematic in thermostated ion irradiation and ion beam analysis apparatus, as the operation of temperature feedback systems can be significantly distorted by this effect.

電子軌道解析による大面積電子ビーム照射現象の基礎的研究

In large-area electron beam (EB) irradiation method, uniformly high energy EB can be obtained without focusing the beam. Large-area EB can be used for melting and evaporating metal surface instantly. Furthermore, the tip of convex shape is often rounded after large-area EB irradiation with remarkable material removal at the tip. This phenomenon is probably caused due to the electrons concentration at the tip. However, electrons behavior near the workpiece surface during large-area EB irradiation has not yet been clarified. In this study, electron track analysis was conducted in order to clarify electrons behavior during large-area EB irradiation. At first, analytical model of the large-area EB irradiation apparatus was built. Then, the EB diameter on the workpiece surface was experimentally measured with different energy density in order to evaluate the accuracy of our analytical model.

Photodynamic therapy using a novel irradiation source, LED lamp, is similarly effective to photodynamic therapy using diode laser or metal-halide lamp on DMBA- and TPA-induced mouse skin papillomas.

Photodynamic therapy (PDT) is useful for superficial skin tumors such as actinic keratosis and Bowen disease. Although PDT is non-surgical and easily-performed treatment modality, irradiation apparatus is large and expensive. Using 7, 12-dimethylbenz[a]anthracene (DMBA) and 12-ο-tetradecanoylphorbol-13-acetate (TPA)-induced mouse skin papilloma model, we compared the efficacy of TONS501- and ALA-PDT with a LED lamp, a diode laser lamp or a metal-halide lamp on the skin tumor regression. TONS501-PDT using 660nm LED lamp showed anti-tumor effect at 1day following the irradiation and the maximal anti-tumor effect was observed at 3days following the irradiation. There was no significant difference in the anti-tumor effects among TONS501-PDT using LED, TONS501-PDT using diode laser, and 5-aminolevulinic acid hydrochloride (ALA)-PDT using metal-halide lamp. Potent anti-tumor effect on DMBA- and TPA-induced mouse skin papilloma was observed by TONS501-PDT using 660nm LED, which might be more useful for clinical applications.

WE‐E‐BRE‐07: High‐Throughput Mapping of Proton Biologic Effect

Purpose:To systematically relate the relative biological effectives (RBE) of proton therapy to beam linear energy transfer (LET) and dose.Methods:Using a custom irradiation apparatus previously characterized by our group, H460 NSCLCs were irradiated using a clinical 80MeV spot scanning proton beam. Utilizing this system allowed for high‐throughput clonogenic assays performed in 96‐well tissue culture plates as opposed to the traditional 6‐well technique. Each column in the 96‐well plate received a set LET‐dose combination. By altering the total number of dose repaintings, numerous dose‐LET configurations were examined to effectively generate surviving fraction (SF) data over the entire Bragg peak. The clonogenic assay was performed post‐irradiation using an INCell Analyzer for colony quantification. SF data were fit to the linear‐quadratic model for analysis.Results:Irradiation with increasing LETs resulted in decreased cell survival largely independent of dose. A significant correlation between LET and SF was identified by two‐way ANOVA and the extra sum‐of‐squares F test. This trend was obscured at the lower LET values in the plateau region of the Bragg peak; however, it was clear for LET values at and beyond the Bragg peak. Data fits revealed the SF at a dose of 2Gy (SF2) to be 0.48 for the lowest tested LET (1.55keV/um), 0.47 at the end of the plateau region (4.74keV/um) and 0.33 for protons at the Bragg peak (10.35keV/um). Beyond the Bragg peak we measured SF2s of 0.16 for 15.01keV/um, 0.02 for 16.79keV/um, and 0.004 for 18.06keV/um.Conclusion:We have shown that our methodology enables high‐content automated screening for proton irradiations over a range of LETs. The observed decrease in cellular SF in high LET regions confirms an increased RBE of the radiation and suggests further evaluation of proton RBE values is necessary to optimize clinical outcomes.Rosalie B. Hite Graduate Fellowship in Cancer Research, NIH Program Project Grant P01CA021239

Swelling characterization of photo-cross-linked gelatin methacrylate spherical microgels for bioencapsulation

AbstractThe swelling behavior of biocompatible and biodegradable polymers is important for the delivery and release of cells and drugs in biomedical applications. This study reported the swelling characteristics of photo-cross-linked gelatin methacrylate (GelMa) spherical microgels. Spherical microgels were generated in a microfluidic system consisting of a co-axial flow-focusing device for microdroplet generation and an ultraviolet (UV) irradiation apparatus for polymerization. At a low flow rate ratio (<0.14), the 9 wt.% GelMa spherical microgels were smaller than the 6 wt.% ones. In contrast, at a high flow rate ratio (>0.14), the results were reversed. Overall, a proportional relationship was observed between the flow rate ratio and the droplet size. The increased GelMa concentration improved the mechanical properties and increased the swelling ratios. The possibility of bioencapsulation was demonstrated, with good viability of 3T3 cells encapsulated in the spherical microgels.

Visible Light Photocatalysis. A Green Choice?

The “green” character of a series of reaction carried out under visible light photocatalysis has been evaluated by calculating the Process Mass Intensity (PMI) and by means of the EATOS software. The indexes obtained were likewise calculated for the thermal version of the same reactions for the sake of comparison. The role of solvents, of the photocatalyst used and of the irradiation apparatus are discussed.

Development of a Novel Emergency Hemostatic Kit for Severe Hemorrhage

Photocrosslinkable chitosan (Az-CH-LA) contains lactose moieties and photoreactive azide groups, and its viscous solution forms an insoluble hydrogel on exposure to UV irradiation. We previously developed an emergency hemostatic kit using the Az-CH-LA solution, calcium alginate, and a UV irradiation apparatus. However, a suitable UV irradiation apparatus is required to effectively convert the Az-CH-LA solution into a hydrogel, and power supply to use the UV irradiation apparatus may not always be available in a disaster area or battlefield. To address this problem, we produced a portable, battery-powered UV irradiation apparatus constituting a novel hemostatic kit for severe hemorrhage. When the hemostatic kit using the UV irradiation apparatus was examined using a rat model of severe hemorrhage, the survival rate increased up to 73%. Hematological values as markers of hemorrhage did not change significantly over the first 3 days. In this study, we describe the characteristics of a portable UV irradiation apparatus and its use in an emergency hemostatic kit prepared using Az-CH-LA and calcium alginate for severe hemorrhage.

Measurements of SiO2, Polycrystalline Silicon, and Si3N4 Etching Yields Depending on Ion Incident Angle

The ion incident angle dependences of the etching yields of SiO2, polycrystalline silicon (poly-Si), and Si3N4 were studied using a plasma beam irradiation apparatus. The angle dependences were affected not only by the etchant chemistry produced by Ar and/or fluorocarbon gas plasmas, but also by the incident ion energy. Since the incident etchant characteristics were measured, the results are useful for constructing an etching profile simulator.

Murine partial-body radiation exposure model for biodosimetry studies — Preliminary report

Abstract The objective of the present study was to establish a murine partial-body radiation exposure model for studies supporting the identification and validation of novel biological dosimetry diagnostic assays. A lead shielding – Plexiglas ® irradiation apparatus with cutouts to permit irradiation of single-mouse-holder constrained CD2F1 male mice to total-body (3/3), mid- and lower-body (2/3), mid-body only (1/3), and 100% lead shielding sham-treated (0 Gy) controls (0/3) with a 250-kVp X-ray source (dose: 6 Gy, dose rate: 0.50 Gy min −1 ) was used. Doses and dose uniformity were measured using alanine – electron paramagnetic resonance (EPR) and ionization chambers. Dosimetry mapping results showed ∼2 and ∼12% non-uniformity in the radiation fields for the two smaller (1/3, 2/3) and one larger (3/3) fields, respectively. Hematology results showed no marked differences in neutrophil and platelet counts 1 and 2 days (d) after irradiation. The lymphocyte counts, as expected, demonstrate a progressive decline below baseline levels 1 and 2 d after irradiation with increasing fraction of the body exposed, while the neutrophil to lymphocyte ratios show the inverse effect, with a progressive increase with the fraction of body exposed. The bone marrow biomarker, Flt3 ligand, demonstrated a progressive increase in values with increasing fraction of the body exposed; the 2 d response was enhanced compared to 1 d. The radioresponse 1 d after irradiation for the acute phase reactant protein biomarker, serum amyloid A (SAA) that is synthesized by the liver, was significantly influenced depending on whether the mouse head was in the radiation field. Use of multiple biomarkers based on hematology and proteomic targets provide an enhancement in early-phase partial-body radiation exposure assessment.

Depletion of New Neurons by Image Guided Irradiation

Ionizing radiation continues to be a relevant tool in both imaging and the treatment of cancer. Experimental uses of focal irradiation have recently been expanded to studies of new neurons in the adult brain. Such studies have shown cognitive deficits following radiation treatment and raised caution as to possible unintentional effects that may occur in humans. Conflicting outcomes of the effects of irradiation on adult neurogenesis suggest that the effects are either transient or permanent. In this study, we used an irradiation apparatus employed in the treatment of human tumors to assess radiation effects on rat neurogenesis. For subjects we used adult male rats (Sprague-Dawley) under anesthesia. The irradiation beam was directed at the hippocampus, a center for learning and memory, and the site of neurogenic activity in adult brain. The irradiation was applied at a dose-rate 0.6 Gy/min for total single-fraction, doses ranging from 0.5 to 10.0 Gy. The animals were returned to home cages and recovered with no sign of any side effects. The neurogenesis was measured either 1 week or 6 weeks after the irradiation. At 1 week, the number of neuronal progenitors was reduced in a dose-dependent manner with the 50% reduction at 0.78 Gy. The dose–response curve was well fitted by a double exponential suggesting two processes. Examination of the tissue with quantitative immunohistochemistry revealed a dominant low-dose effect on neuronal progenitors resulting in 80% suppression of neurogenesis. This effect was partially reversible, possibly due to compensatory proliferation of the remaining precursors. At higher doses (>5 Gy) there was additional, nearly complete block of neurogenesis without compensatory proliferation. We conclude that notwithstanding the usefulness of irradiation for experimental purposes, the exposure of human subjects to doses often used in radiotherapy treatment could be damaging and cause cognitive impairments.