Irradiation System Research Articles

Experimental study of ISHTAR thermostatic irradiation device for the MARIA research reactor

Materials and core components for the next generation power reactors technologies require testing that can be performed in existing research reactors. Such experiments employ devices dedicated to reflect the relevant thermal and neutron parameters simulating conditions present in, for example, but not limited to, HTGR reactors. A novel thermostatic irradiation device named ISHTAR (Irradiation System for High-Temperature Reactors) has been designed and constructed in the MARIA research reactor. Its mission is to enable irradiation of samples in controlled, homogeneous temperature field reaching 1000°C and inert gas atmosphere. The high temperature is achieved by a combination of electric and gamma heating, together with carefully designed thermal insulation. Additionally, samples holder made of graphite with high thermal conductivity enables the temperature homogenization in all directions. Device will be placed inside the Beryllium matrix of MARIA core and cooled with forced circulation of water from the reactor pool loop. This paper presents the outcome of experiments conducted with the rig prototype in external hydraulic mock-up of the MARIA reactor irradiation channel. The results have proved that the desired conditions for irradiation of the samples were achieved and their comparison against computational data has shown the adequacy of the design process. Finally, the loss of flow scenario was tested in protected and unprotected conditions (meaning with and without the safety system based on temperature feedback), proving the operational safety of the ISHTAR design. Experimental results will be used in the future to validate the numerical models (two and three dimensional) of the irradiation rig, providing an improved understanding of free convection and radiation phenomena modeling.

Optoelectronic characteristics of as-deposited, annealed and I2 – Treated thin films of newly synthesized organic dye based on pyrrolo[2,3-b]pyrrole

Novel heterocyclic dyes were synthesized by attaching different electron-rich aromatics to the pyrrolo[2,3-b]pyrrole system by microwave irradiation system provided with condensation unit. The final push-pull conjugated dyes were yielded by azo coupling of PPY with aniline, 1-naphthylamine and N,N-dimethylaniline. Thin films of compound 3 have been chosen and prepared using thermal evaporation technique and investigated by FTIR and UV – VIS – NIR spectroscopy. Annealing out of PPY films at relatively low temperature (≤100 ​°C) for 3–6 ​min has been proved to notably reduce the energy gap and enhance both absorption and refractive indices. They manifested a fast response and high sensitivity toward iodine vapor with a low recovery time indicating a reversibility of iodine adsorption process.

UTMD promoted local delivery of miR-34a-mimic for ovarian cancer therapy

MicroRNA-mediated gene therapy is emerging as a promising method for the treatment of ovarian cancer, but the development of miRNA mimic delivery vectors is still in its infancy, where the safety and efficacy of miR-34a-mimic remain unknown. Ultrasound-targeted microbubble destruction (UTMD) can be an effective and minimally invasive tool for the delivery of miR-34a-mimic in vitro and in vivo. Here, we describe a high-efficiency gene delivery strategy by using miR-34a-mimic loaded folate modified microbubbles (miR-34a-FM) with a portable ultrasonic irradiation system. Ultrasonic parameters, including acoustic intensity (AI), exposure time (ET) and duty cycle (DC), were optimized and the optimal acoustic condition (1.0 W/cm2, 20 s, and 15% DC) was used to deliver miRNA-34a into cells in vitro. MiR-34a mimic was successfully introduced into the cytoplasm and was found to inhibit proliferation and induce apoptosis of SK-OV-3 cells. Next, miR-34a-mimic was delivered to tumor tissue via UTMD, inhibiting tumor growth and prolonging the survival time of mice. In summary, UTMD-mediated miR-34a-mimic delivery has potential application in the clinical treatment of ovarian cancer.

Technological process of food irradiation and dosimetric support

The study represents the main types and technical characteristics of irradiation sources currently used for processing of foodstuffs. An absorbed irradiation dose is considered in the context of the technological goals of such treatment. The article discusses the standard dosimetry systems for irradiation treatment of foods, as well as the criteria for calibration and mapping of doses absorbed by a product. The article includes several references to international and Russian regulatory documents on dosimetry systems for food irradiation.

Effect of pH and water irradiation with the electromagnetic field on the gelation of gelatin solutions

The rate of gelation was determined from the curve slope of the dependence of the gelatin solution relative viscosity on time at different pH. It was found that slow gelation of 2 % gelatin solution occurs at T = 293 K, and the degree of fluidity significantly depends on рН. The most stable jellies are formed at the isoelectric point (рН = 4.7). There are significant differences in the physical state of jellies prepared on irradiated water and control samples. Prepared on unirradiated water jellies are more mobile and retain fluidity at T = 293 K regardless of рН. There is a partial or full melting of the jellies with the increase in temperature at 297 K; however solid state remains for irradiated systems at pH = 4 and 4.7. It was shown that the viscosity of the ir-radiated solution and the rate of its increase are higher in comparison with the control samples at all pH val-ues except рН = 2. The observed phenomenon can be caused by the weakening of the hydration of polymer macromolecules in the activated water, which facilitates their association and the formation of a structured system.

Viruses such as SARS-CoV-2 can be partially shielded from UV radiation when in particles generated by sneezing or coughing: Numerical simulations

UV radiation can inactivate viruses such as SARS-CoV-2. However, designing effective UV germicidal irradiation (UVGI) systems can be difficult because the effects of dried respiratory droplets and other fomites on UV light intensities are poorly understood. Numerical modeling of UV intensities inside virus-containing particles on surfaces can increase understanding of these possible reductions in UV intensity. We model UV intensities within spherical approximations of virions randomly positioned within spherical particles. The model virions and dried particles have sizes and optical properties to approximate SARS-CoV-2 and dried particles formed from respiratory droplets, respectively. In 1-, 5- and 9-µm diameter particles on a surface, illuminated by 260-nm UV light from a direction perpendicular to the surface, 0%, 10% and 18% (respectively) of simulated virions are exposed to intensities less than 1/100th of intensities in individually exposed virions (i.e., they are partially shielded). Even for 302-nm light (simulating sunlight), where absorption is small, 0% and 11% of virions in 1- and 9-µm particles have exposures 1/100th those of individually exposed virions. Shielding is small to negligible in sub-micron particles. Results show that shielding of virions in a particle can be reduced by illuminating a particle either from multiple widely separated incident directions, or by illuminating a particle rotating in air for a time sufficient to rotate through enough orientations. Because highly UV-reflective paints and surfaces can increase the angular ranges of illumination and the intensities within particles, they appear likely to be useful for reducing shielding of virions embedded within particles.

Differences in mind and body restorativeness and job satisfaction with the Komore-bi irradiation system during the rest time for the nursing home stafff

Differences in mind and body restorativeness and job satisfaction with the Komore-bi irradiation system during the rest time for the nursing home stafff

Assessment of Gadobutrol Safety in Combination with Ionizing Radiation Using a Preclinical MRI-Guided Radiotherapy Model.

MR-linac technology enhances the precision of therapeutic radiation by clarifying the tumor-normal tissue interface and provides the potential for adaptive treatment planning. Accurate delineation of tumors on diagnostic magnetic resonance imaging (MRI) frequently requires gadolinium-based contrast agents (GBCAs). Despite generally being considered safe, previous literature suggests that GBCAs are capable of contrast-induced acute kidney injury (AKI). It is unclear if the risk for AKI is enhanced when GBCAs are administered concurrently with ionizing radiotherapy. During irradiation, gadolinium may be liberated from its chelator which may induce AKI. The goal of this work was to determine if radiation combined with GBCAs increased the incidence of AKI. Using a preclinical MRI-guided irradiation system, where MRI acquisitions and radiation delivery are performed in rapid succession, tumor-bearing mice with normal kidney function were injected with GBCA and treated with 2, 8 or 18 Gy irradiation. Renal function was assessed on days three and seven postirradiation to assess for AKI. No clinically relevant changes in blood urea nitrogen and creatinine were observed in any combination of GBCA and radiation dose. From these data, we conclude that GBCA in combination with radiation does not increase the risk for AKI in mice. Additional investigation of multiple doses of GBCA administered concurrently with irradiation is warranted to evaluate the risk of chronic kidney injury.

Methodology of Defining of the Radiation Therapy Components for Various Methods of Patients’ Treating Using Medical Linear Accelerators and Gamma-Therapeutic Devices

One of the main factors affecting the effectiveness of radiation therapy is the constancy of the patient’s position on the treatment table created by immobilization devices of various designs and held throughout the entire irradiation procedure, which guarantees the accuracy of the delivery of the prescribed dose distribution. The purpose of the work was to establish the numerical values of the dominant components of a radiation therapy session for each of the irradiation techniques most commonly used in clinical practice of the radiation therapy.To determine the numerical values of the components of the radiation therapy session, the authors have measured each component for some clinical cases of patients’ irradiation placed. The patients had been diagnosed with the following malignant tumours: prostate cancer, breast cancer, lung cancer, head and neck tumours. More than 2000 individual measurements have been carried out with the help of such medical linear accelerators as "Clinac", "Unique", "Truebeam", and the gamma-therapeutic apparatus named "Theratron".The numerical values of the time spent on 3 groups of parameters of an irradiation session were established: the mechanical parameters of the radiation therapy equipment, the functional characteristics of the irradiation systems and the parameters that directly depend on the personnel involved in an irradiation procedure.According to the measurement results, the flow diagram for the procedures of verifying a patient’s position on the therapeutic table (2 different techniques), preceding their irradiation and the radiation therapy procedures themselves was proposed. It has been shown that a number of session components can run in parallel to each other thus optimizing the time spent by a patient in the treatment room.Using the obtained values of the time spent on the radiation session parameters it is possible to actualize the mathematical model that will allow the medical physicist to determine in advance the duration of the irradiation session at the stage of treatment planning and choose a radiation therapy technique taking into account the individual parameters of the irradiation session in each particular clinical case.

Ультрафіолетова установка для опромінення тварин з автоматичним керуванням

Modern technologies for the production of livestock products provide for long-term keeping of young animals indoors with an artificial microclimate. That is, it is expected to maintain within the required limits of temperature, humidity, gassiness, lighting level, etc. In particular, to compensate for solar radiation, ultraviolet irradiation units are used. The main criterion of UV irradiation is the dose, which is individual for each species and age of animals. The obtained amount of irradiation depends on the type and power of the radiation source, the height of the suspension, the continuance of the irradiation process. Therefore, existing mobile UV irradiators need to be upgraded for efficient operation. The purpose of the study is to develop a UV irradiation system for a room with pigs of different ages and weights in pens with the possibility of automatically providing the required dose. In order to increase the accuracy maintenance of the recommended dose of UV radiation, the authors use a video camera and a device with software that fulfils the effect of "pattern recognition" and automatic control of the installation during its movement over animals, which are kept in boxes in different age groups. Experimental studies showed that in the experimental groups of pigs, where irradiation was carried out using the developed unit of automatic control of the UV installation, the set of live weight in piglets was 20-25 % more than in the control group.

Synthesis of Silver Nanocatalysts Using Microwave Irradiation in Ionic Liquid for Reduction of Carbon Dioxide to CO By Solar-Driven Electrochemical

Over the last few decades electrochemical CO2 reduction has attracted attention as a promising technology for greenhouse gas reduction. The Carbon monoxide product from CO2 reduction is of interest as a component of syngas for methanol synthesis. Silver is a reactive electrocatalyst toward carbon dioxide reduction to Carbon monoxide among single metals (Au, Zn etc.). In order to carry out CO2 reduction reaction effectively, it is require to nano-sized electro catalyst for wide active area. However, there is aggregation issue of nano-sized particle in liquid phase reduction method from metal precursor. It can be solved simply using of ionic liquid as a solvent and capping agent to suppress aggregation of nano-particle. In addition, Microwave-assisted fabrication has much potential due to their distinctive characteristics such as rapid heating ability, efficient and uniform internal heating, and relatively short process time.Here we describe its use as a single electrocatalyst made in Microwave method with Ionic liquid for reduction of CO2 to CO. We have simply synthesized Ag nanoparticles with an ultra-fine size (~20nm) by microwave irradiation process using Ag precursors dissolve in Ionic liquid. Silver carbonate (Ag2CO3, purchased from Sigma Aldrich) as a precursor was dissolved in Ionic liquid, Butyl-3-methylimidazolium tetrafluoroborate (BMIM BF4-, purchased from C-TRI). The 5mL mixture solutions with a concentration of 10, 20 and 30mM were prepared by stirring under atmosphere at room temperature. Each mixture solution was heated by microwave irradiation system (CEM Co.,Ltd Discover) at the power of 10~30W within just 10min.Characterization of synthesized silver nanoparticles was analyzed by Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) to confirm the morphology, chemical state, and crystal structure of the samples. XRD analysis showed (111), (200), (220), (311), and (222) diffractions of Ag metal with a face-centered cubic structure, confirming that the silver nanoparticles could be synthesized. TEM images showed that the nanoparticles have ultra-fine sized silver, less than 20nm without aggregation. Based on CO2 reduction reaction (CO2RR) response, the elctrocatalystic performance of synthesized silver was evaluated. In order to compare the performance, the same mass of commercial Ag and carbon black were used in three electrode system with 0.5M KHCO3 aqueous solution saturated with CO2. The catalytic potential reduced 0.374eV compared to carbon black.In order to confirm the efficiency of Solar-driven electrochemical carbon dioxide reduction, synthsized silver nano catalyst of 9mg/cm2 was loaded at the cathode(6.25cm2) in electrochemical reactor which is a closed two-component separated by anion exchange membrane (Sustainion® X37-50, Dioxide Materials). The anode was IrOx (purchased from Dioxide materials) sprayed on Carbon paper (9cm2). A Si solar cell of series connection solar panels supplied electric power to electrochemical reactor. We achieved the Faradaic Efficiency of 92% to Carbon monoxide conversion by synthesized silver catalyst. We obtained 8.81% to Power conversion efficiency employing series connected Si photovoltaics for CO2 conversion to CO.

Influence of irradiation sources on the efficiency of copper-modified magnetite for photo-Fenton degradation of sulfathiazole

A comparison of the catalytic activity of the copper-modified magnetite was carried out under different conditions (dark and irradiated) and irradiation systems (460 nm Vis-LED, 370 nm UV-LED and Solar) in the degradation of the antibiotic sulfathiazole (STZ). The catalyst copper-modified magnetite presented a mesoporous structure, with a high absorption range (200–800 nm), band gap of 1.80 eV characteristic of iron and copper oxides, negative surface charge (− 24.6 mV) at neutral pH and high stability in solution (absence of iron and copper leaching). The results showed that the degradation kinetics of STZ increased in the following order in relation to irradiation: dark < Vis-LED < UV-LED < Solar), promoting complete degradation after 15 min, indicating that under solar and UV irradiation the catalytic activity is improved, due to an increase in the speed of the Fe–Cu redox reactions from a quick transfer of electrons that occur on the surface of the catalyst, further facilitating the formation of HO· radicals. The results have further demonstrated that the copper-modified magnetite can promote heterogeneous Fenton processes under LED or solar irradiation and be applied to effective degradation of micropollutants in wastewaters and have proven the versatility and high catalytic activity.

Impact of Small Organic Molecules on the Degradation of Methylene Blue in VUV/UV Irradiation System

Generally, small organic molecules (SOM) in waters are always as the ·OH scavengers in the AOPs and reduce its efficiency. In this paper, the studies are focused on the impact of small organic molecules on the degradation of methylene blue (MB) in VUV/UV irradiation system. Results show that the degradation of MB in VUV/UV process were divided into two section: the inhibition and acceleration with SOM addition. MB completely degraded at 30 min in VUV/UV system with addition of SOM, but the degradation was significantly inhibited in UV/H2O2/SOM system. The result show that the formation of H2O2 in water under VUV/UV irradiation and the addition of SOM improved the generation of H2O2. The decomposition of H2O2 at the maximum accumulated contents accelerate the MB degradation. This study provides an efficient VUV/UV process for reduce the interference of SOM, which could be applied in water treatment.

Effect of ultraviolet germicidal irradiation of the air on the incidence of upper respiratory tract infections in kittens in a nursery.

To evaluate the effect of UV germicidal irradiation of the air on the incidence of upper respiratory tract infections (URIs) in kittens in a nursery. 4- to 8-week-old kittens admitted to a kitten nursery in 2016 and 2018. 2 UV germicidal irradiation systems (1 within the heating, ventilation, and air conditioning system and 1 attached to the ceiling) were installed in a kitten nursery. Data were collected on the number of kittens in which a URI was diagnosed by means of a physical examination. The incidence of URIs was compared between 2016, when no UV systems were used, and 2018, when the UV systems were used. The overall incidence of URIs in 2016 was 12.4 cases/100 kitten admissions and in 2018 was 1.6 cases/100 kitten admissions, a significant decrease of 87.1% between the years. A significant reduction in the incidence of URIs in kittens in a nursery was noted when the UV germicidal irradiation systems were used. Therefore, airborne transmission of feline respiratory pathogens may be more important than has been previously recognized. Ultraviolet germicidal irradiation systems that disinfect the air may be an effective adjunct to standard infection prevention and control protocols in reducing the risk of the transmission of respiratory pathogens among kittens in nurseries and shelters. However, additional studies are needed to confirm the findings reported here.

Laser and LED Hybrid Plant Lighting System Design Based on the Particle Swarm Algorithm

This paper developed light-emitting diode (LED) and laser models suitable for the design of uniform surface irradiation systems that use computer algorithms. During the evaluation factor for a two-dimensional particle swarm algorithm, the effects of energy utilization and uniformity were comprehensively considered and LED and laser models were given. The optimal design method was used with a laser and LED hybrid light source. According to the lighting requirements of lettuce, three types of lighting were simulated for the LED and laser models, and the best simulation results were selected for experiments. The experiment verified the feasibility of the above method and obtained a laser and LED hybrid lighting system with an energy utilization rate of about 78% and a uniformity of up to 85%.

Degradation of aqueous bisphenol A in the CoCN/Vis/PMS system: Catalyst design, reaction kinetic and mechanism analysis

Low levels of pharmaceutical and personal care products (PPCPs) in the environment have attracted widespread attention as a new class of organic pollutants. Degradation of these PPCPs by optimizing advanced oxidation processes (AOPs) is highly desirable, but remains a huge challenge. Here, the Co sites embedded in carbon nitride catalyst (CoCN) was synthesized by a simple one-step pyrolysis of Co-based Zeolitic Imidazolate Framework-67 (ZIF-67) and melamine, of which highly dispersed Co atom sites were uniformly doped in the CN ring of g-C3N4. In the optimized system of visible light irradiation involving CoCN and peroxymonosulfate (CoCN/Vis/PMS system) (λ ≥ 420 nm, [PMS] = 0.2 g L-1, pH = 7.0), 100% of bisphenol A (BPA, 20 mg L-1) was removed after 2 min and the total organic carbon (TOC) removal rate of BPA reached 88.8% after 90 min reaction. Detailed characterization showed that a specially designed unique Co-N bond structure was crucial for the high degradation performance of BPA in the CoCN/Vis/PMS system. HO∙, SO4∙-, O2∙-, h+ and 1O2 contributed to the BPA degradation in the CoCN/Vis/PMS system. Besides, the effect of solution pH and several common anions in environmental water on BPA removal was evaluated. Several typical pollutants, sulfamethoxazole (SMX), ciprofloxacin (CIP), 4-chlorophenol (4-CP) and atrazine (ATZ), were effectively degraded by the same CoCN/Vis/PMS system, which exhibited universal applicability of this AOP reaction. The cycling degradation experiment showed the stability and reusability of the CoCN/Vis/PMS system. This work offers immense hope to the environmental purification and provides numerous new opportunities for the effective removal of other pollutants beyond BPA, SMX, CIP, 4-CP and ATZ.

Application of the Ultraviolet Germicidal Irradiation system can reduce microbial surface contamination in ambulance compartments.

Emergency responders play a vital role in the treatment of critically ill or injured patients, as they are often the first point of contact for the patient in the healthcare setting. Emergency medical services also play a vital role in the prevention and control of the transmission of communicable diseases and ensuring best practice infection control is enacted. Lindsley et al. (2018) recently examined the efficacy and impact of an ultraviolet germicidal irradiation (UVGI) system to disinfect the interior of an ambulance. A critique of this article is presented in the following.&#x0D;

A high-throughput alpha particle irradiation system for monitoring DNA damage repair, genome instability and screening in human cell and yeast model systems.

Ionizing radiation (IR) is environmentally prevalent and, depending on dose and linear energy transfer (LET), can elicit serious health effects by damaging DNA. Relative to low LET photon radiation (X-rays, gamma rays), higher LET particle radiation produces more disease causing, complex DNA damage that is substantially more challenging to resolve quickly or accurately. Despite the majority of human lifetime IR exposure involving long-term, repetitive, low doses of high LET alpha particles (e.g. radon gas inhalation), technological limitations to deliver alpha particles in the laboratory conveniently, repeatedly, over a prolonged period, in low doses and in an affordable, high-throughput manner have constrained DNA damage and repair research on this topic. To resolve this, we developed an inexpensive, high capacity, 96-well plate-compatible alpha particle irradiator capable of delivering adjustable, low mGy/s particle radiation doses in multiple model systems and on the benchtop of a standard laboratory. The system enables monitoring alpha particle effects on DNA damage repair and signalling, genome stability pathways, oxidative stress, cell cycle phase distribution, cell viability and clonogenic survival using numerous microscopy-based and physical techniques. Most importantly, this method is foundational for high-throughput genetic screening and small molecule testing in mammalian and yeast cells.

The LED phyto lighting for improving the environmental friendliness of growing and productivity of lettuce varieties with red and green leaves

The intensively developing area of modern phytophysiology is the ecological plants physiology, which important section is the ecology of photosynthesis, by which we understand the intensity and photosynthesis productivity dependence on environmental factors, primarily on optical radiation. The urgent problem of growing plants under artificial conditions is to increase energy efficiency, reduce energy intensity and degree of environmental impact. Using LED irradiators with the function of controlling the spectral composition and optical radiation power, it is possible to increase photosynthesis efficiency and vegetable crop productivity in greenhouses. The comparative study of the effect of sodium lamp radiation and LED irradiators with different spectral composition on the growth and productivity lettuce varieties with red leaves (Anthony, Lolo-Rossa) and with green leaves (Levistro, Lifli), was conducted. The research results showed the different susceptibility of lettuce varieties to the spectral composition of radiation. For the Anthony, Levistro and Lolo-Rossa lettuce varieties, LED radiation application provided the positive effect on plant productivity (8-20%) compared to sodium lamps, and simultaneous reduced in energy consumption of the irradiation system by 40 - 50%. Diodes emission increase in the blue region of the spectrum had a significant positive effect on the synthesis of anthocyanins in the culture of lettuce varieties with red-leaves, compared to sodium lamps. For these varieties, a variable irradiation regime is necessary with a change in the spectrum and increase in the proportion of blue radiation towards the end of growth.

Sterilization effectiveness of in-duct ultraviolet germicidal irradiation system in liquid desiccant and indirect/direct evaporative cooling-assisted 100% outdoor air system

Microorganism contamination in air conditioning systems can cause respiratory diseases in building occupants. This study aims to evaluate and predict the performance of an in-duct ultraviolet germicidal irradiation (ID-UVGI) system to reduce the microorganisms that can grow in the liquid desiccant and indirect/direct evaporative cooling-assisted 100% outdoor air system (LD-IDECOAS). Bacteria and mold on the direct evaporative cooling (DEC) element and in the outdoor and supply air were monitored using a swab and Petrifilm for surfaces and impact sampler for air during the operation of the LD-IDECOAS. Microbial contamination was first verified in the air before performing the sterilization experiment. The experimental results showed that the airborne bacteria were reduced by 78.3% after the operation of the ID-UVGI system but there was almost no reduction in the airborne mold. The bacteria and mold concentration on the DEC surface were decreased by 99.7% and 96.7% respectively 3 h after the ID-UVGI operation. Even after the ID-UVGI system was operated for 6 days, the microbial contamination in the downstream water was not decreased significantly; the inside of the DEC element was suspected to be improperly sterilized. The operating times of the ID-UVGI system needed to inactivate the microorganisms were predicted from the UV–C intensity distribution by irradiation analysis. Legionella sp. and Penicillium sp. were predicted to be inactivated by 99.9% with UV–C exposures of 6 s and 15 min 57 s or less respectively when the LD-IDECOAS is operated at the highest air flow rate.