Radiation sterilization of tissue allografts:A review

Tissue substitutes are required in a number of clinical conditions for treatment of injured and diseased tissues.Tissues like bone,skin,amniotic membrane and soft tissues obtained from human donor can be used for repair or reconstruction of the injured part of the body.Allograft tissues from human donor provide an excellent alternative to autografts.However,major concern with the use of allografts is the risk of infectious disease transmission.Therefore,tissue allografts should be sterilized to make them safe for clinical use.Gamma radiation has several advantages and is the most suitable method for sterilization of biological tissues.This review summarizes the use of gamma irradiation technology as an effective method for sterilization of biological tissues and ensuring safety of tissue allografts.

The characteristics of DNA repair synthesis induced by DNA polymerase β in hepatoma cells after γ rays irradiation

AIM To investigate the effects of DNA repair synthesis induced by DNA polymerase β in hepatoma cells after γ ray irradiation. METHODS Cell nuclei were prepared from SMMC LTNM hepatoma which is a transplanted human liver cancer born on nude mice. Samples were irradiated with 60 Co γ rays at different doses or dose rates. N ethylmaleimide (NEM) and ddTTP were used as selective inhibitors to DNA polymerases. The reaction of DNA repair synthesis was carried out with the selective inhibitor test. RESULTS It was found that the 3H TTP incorporation in irradiated nuclei or calf thymus DNA was significantly higher than that in the non irradiated ones, under the conditions of DNA polymerase α or γ being inhibited. When NEM and ddTTP which selectively inhibits DNA polymerase β both existed in the DNA repair synthesis reaction mixture, the 3H TTP incorporation in irradiated DNA did not significantly increased. Furthermore, 3H TTP incorporation into DNA of SMMC LTNM hepatoma nuclei was higher than that of normal hepatocyte nuclei ( P <0 01). The DNA repair synthesis induced by DNA polymerase β reacted more fast in hepatoma nuclei than in hepatocyte nuclei. CONCLUSION The effects of DNA repair synthesis induced by DNA polymerase β in some tumor cells might be stronger than that in normal cells, which may facilitate the cells to repair DNA damages from radiation.

Characteristics of radiation and convection heat transfer in indirect near-infrared-ray heating chamber

Numerical study was performed to evaluate the characteristics of combined heat transfer of radiation, conduction and convection in indirect near infrared ray （N/R） heating chamber. The effects of important design parameters such as the shape of heat absorbing cylinder and heat releasing fin on the pressure drop and heat transfer coefficient were analyzed with different Reynolds numbers. The Reynolds numbers were varied from 103 to 3x106, which was defined based on the hydraulic diameter of the heat absorbing cylinder. Analyses were performed to obtain the inner and outer flow and the temperature distributions in the heat absorbing cylinder and the rates of radiation heat transfer and convection heat transfer. As the Reynolds number increases, the convection heat transfer rate is increased while the radiation heat transfer rate is decreased. The average convection heat transfer rate follows a power rule of the Reynolds number. Addition of three-dimensional heat releasing fin to the outside of the heat absorbing cylinder enhances the convection heat transfer.

KELEA, Cosmic Rays, Cloud Formation and Electromagnetic Radiation: Electropollution as a Possible Explanation for Climate Change

The basic premise of this article is that human generated electromagnetic radiation is contributing to global warming. It may do so by diverting an energy force termed KELEA (kinetic energy limiting electrostatic attraction) from its presumed association with cosmic rays. Cosmic ray delivered KELEA is viewed as normally participating in the formation of cloud condensation nuclei (CCN). It may do so by transforming electrostatically inert particles into electrostatic aerosols capable of acting as CCN. The resulting clouds act as a reflective barrier to some of the infrared radiation from the sun and, thereby, reduce the earth’s heat. This article proposes that increasing levels of electromagnetic radiation in the atmosphere is reducing the capacity of cosmic rays to deliver adequate KELEA to maintain climate stability through optimal cloud formation. Specifically, the fluctuating electrical fields accompanying electromagnetic radiation may do so by competitively withdrawing some of the KELEA from the incoming cosmic rays. Previously described studies by Dr. Wilhelm Reich attributed to an energy force termed orgone, are consistent with weather activity being inducible using a device that likely delivers KELEA to the atmosphere. In addition to the foregoing consideration, there are many agricultural and industrial applications of KELEA activated fluids that can reduce carbon emissions. It is important that the scope of climate science be broadened to include a detailed understanding of KELEA and of its many potential practical applications in addressing global warming.

Measurement of Gamma-Rays Induced Luminescence Generated in a Sapphire Based Fiber-Optic Radiation Sensor

In this study, we fabricated a sapphire based fiber-optic radiation sensor. To evaluate the fiber- optic radiation sensor, we measured the spectrum and intensity of the luminescence generated from the fiber-optic radiation sensor according to the thickness of the PMMA block by irradiation of gamma rays emitted from a Co-60 source. And the result was compared with the value calculated from the formula of Lambert-Beer.

Effects of sterilization treatments on the analysis of TOC in water samples

Decomposition experiments conducted with and without microbial processes are commonly used to study the effects of environmental microorganisms on the degradation of organic pollutants.However,the effects of biological pretreatment （sterilization） on organic matter often have a negative impact on such experiments.Based on the principle of water total organic carbon （TOC） analysis,the effects of physical sterilization treatments on determination of TOC and other water quality parameters were investigated.The results revealed that two conventional physical sterilization treatments,autoclaving and 60 Co γ-radiation sterilization,led to the direct decomposition of some organic pollutants,resulting in remarkable errors in the analysis of TOC in water samples.Furthermore,the extent of the errors varied with the intensity and the duration of sterilization treatments.Accordingly,a novel sterilization method for water samples,0.45 μm micro-filtration coupled with ultraviolet radiation （MCUR）,was developed in the present study.The results indicated that the MCUR method was capable of exerting a high bactericidal effect on the water sample while significantly decreasing the negative impact on the analysis of TOC and other water quality parameters.Before and after sterilization treatments,the relative errors of TOC determination could be controlled to lower than 3% for water samples with different categories and concentrations of organic pollutants by using MCUR.

Feasibility of using recycled CRT funnel glass as partial replacement of high density magnetite sand in radiation shielding concrete

The recycled cathode ray tube(CRT)funnel glass was used as replacement of magnetite sand in the concrete,and its mass replacement rates were 0,20%,40%and 60%,respectively.The flowability,apparent density and mechanical properties of the radiation shielding concrete were investigated,while itsγ-ray radiation shielding parameters such as linear and mass attenuation coefficients(μandμm,respectively),thickness values of half-value layer(hHVL)and tenth-value layer(hTVL)were obtained by theoretical calculation,experiment and Monte.Carlo N-Particle(MCNP)simulation code.The experimental results show that the flowability of the concrete increases significantly,whilst its apparent density,compressive strength and static elastic modulus decrease slightly.The calculated,simulated and experimentalμm,μ,hHVL and hTVL values of all concrete samples are very consistent at the sameγ-ray photon energy,and it is feasible to use MCNP code to simulateγ-ray radiation shielding parameters of materials.The calculated results show that in a wide range ofγ-ray photon energy,theμm value of the concrete with CRT funnel glass replacing magnetite sand is improved effectively,and its radiation shielding performances are the same as those of the control concrete(M.1).By comprehensively comparing the flowability,mechanical properties andγ-ray radiation shielding properties,the concrete samples with 20%.40%funnel glass as fine aggregate have good performances.

γ radiation caused graphene defects and increased carrier density

We report on a micro-Raman investigation of inducing defects in mono-layer, hi-layer and tri-layer graphene by γ ray radiation. It is found that the radiation exposure results in two-dimensional （2D） and G band position evolution with the layer number increasing and D and D~ bands rising, suggesting the presence of defects and related crystal lattice deformation in graphene. Bi-layer graphene is more stable than mono- and tri-layer graphene, indicating that the former is a better candidate in the application of radiation environments. Also, the DC electrical property of the mono-layer graphene device shows that the defects increase the carrier density.

Effect of Gamma Irradiation on Morpho-Agronomic Characteristics of Groundnut (<i>Arachis hypogaea</i>L.)

Induced mutation in plant improvement has been used in several crops to generate new sources of genetic variations. A study was conducted to determine the effect of different doses of gamma irradiation on different morpho-agronomic characteristics. Agronomic traits that were analyzed included: grain yield, number of pods/plant, number of seeds/plant and weight of 100 seeds and numbers of days to 50% flowering. Morphometric characterisation of the descriptive data included plant height, stem diameter, number of leaves/plant, leaflet length, leaflet width and number of ramification/ plant. Groundnut seeds were treated with various doses of gamma rays (100, 200, 400 and 600 Gy). Among the various dose treatments, gamma rays treatment at 100 Gy resulted in a higher increase of grain yield and other morpho-agronomic parameters especially for the JL24 variety. In fact the gamma irradiation at 100 Gy increased significantly grain yield by 14% for JL24, and 4 % for JL12. The number of pods per plant was increased by 2% for JL12 and 37% for JL24. For the number of seeds per plant, there was a significant increase of 8% for JL12, and 62% for JL24 at 100 Gy. A similar trend was observed for the JL24 at 200 Gy dose. Higher doses of gamma rays (400 and 600 Gy) reduced significantly plant growth and grain yield. The usefulness of the mutants identified in a groundnut breeding program is discussed.

Studies of the radiation environment on the Mars surface using the Geant4 toolkit

The radiation environment on the surface of Mars is a potential threat for future manned exploration missions to this planet.In this study,a simple geometrical model was built for simulating the radiation environment on the Mars surface caused by galactic cosmic rays;the model was built and studied using the Geant4 toolkit.The simulation results were compared with the data reported by a radiation assessment detector(RAD).The simulated spectra of neutrons,photons,protons,α particles,and particle groups Z=3-5,Z=6-8,Z=9-13,and Z=14-24 were in a reasonable agreement with the RAD data.However,for deuterons,tritons,and 3He,the simulations yielded much smaller values than for the corresponding RAD data.In addition,the particles’spectra within the 90 zenith angle were also obtained.Based on these spectra,we calculated the radiation dose that would have been received by an average human body on Mars.The distribution of the dose throughout the human body was not uniform.The absorbed and equivalent doses for the brain were the highest among all of the organs,reaching 62.0±1.7 mGy/y and 234.1±8.0 mSv/y,respectively.The average absorbed and equivalent doses for the entire body were approximately 44 mGy/y and 153 mSv/y,respectively.Further analysis revealed that most of the radiation dose was owing to a particles,protons,and heavy ions.We then studied the shielding effect of the Mars soil with respect to the radiation.The body dose decreased significantly with increasing soil depth.At the depth of 1.5 m,the effective dose for the entire body was 17.9±2.4 mSv/y,lower than the dose limit for occupational exposure.At the depth of 3 m,the effective dose to the body was 2.7±1.0 mSv/y,still higher than the accepted dose limit.

Fast 3D EM scattering and radiation solvers based on MLFMA

As the fastest integral equation solver to date, the multilevel fast multipole algorithm （MLFMA） has been applied successfully to solve electromagnetic scattering and radiation from 3D electrically large objects. But for very large-scale problems, the storage and CPU time required in MLFMA are still expensive. Fast 3D electromagnetic scattering and radiation solvers are introduced based on MLFMA. A brief review of MLFMA is first given. Then, four fast methods including higher-order MLFMA （HO-MLFMA）, fast far field approximation combined with adaptive ray propagation MLFMA （FAFFA-ARP-MLFMA）, local MLFMA and parallel MLFMA are introduced. Some typical numerical results demonstrate the efficiency of these fast methods.

Radionuclide Contents and Physicochemical Water Quality Indicators in Stream, Well and Borehole Water Sources in High Radiation Area of Abeokuta, Southwestern Nigeria

Water samples from streams, hand-dug wells and boreholes in high background radiation areas in Abeokuta, Nigeria have been collected in order to determine the activity concentrations of 40K, 226Ra and 232Th in the samples as well as their physicochemical characteristics. These parameters were evaluated in order to deter-mine the quality of these water sources to the local population, who use these water resources for drinking and domestic activities. Measurements of radioactivity in the water samples were carried out using γ-ray spectroscopy, while standard chemistry methods were used for the physicochemical determinations of these quality parameters. A total of fourteen representative water samples from streams (7), boreholes (4), and hand dug wells (3) were collected for study. The determined activity concentrations of the radionuclides in these samples were used to calculate the effective dose to the population from due to ingestion of and drink-ing the locally available water. The total annual ingestion effective doses were found to vary between 115.00 &#177;1.15μSv and 1362.30 &#177;438.02 μSv. The physicochemical parameters where found to be lower than the prescribed standard safe limits in the water sources except for the nitrate and phosphate levels which were particularly high in the water samples from boreholes and hand-dug wells. The radiation effective ingestion dose due to ingestion of water from dug wells and streams was found to be higher than the dose due to inges-tion of water from borehole sources in the studied areas. The results obtained in this study, have been taken as a baselines for physicochemical parameters and activity concentrations of natural radionuclides in water samples within Odeda and Obafemi-owode parts of Abeokuta, Nigeria.

Fast Neutron Radiation Efiects on Bacillus Subtili

To examine the sterilizing effect and mechanism of neutron radiation, Bacillus subtills var. niger, strain （ATCC 9372） spores were irradiated with the fast neutron from the Chinese fast burst reactor II（CFBR-II）. The plate-count results indicated that the D10 value was 384.6 Gy with a neutron radiation dose rate of 7.4 Gy/min. The rudimental catalase activity of the spores declined obviously with the increase in the radiation dose. Meanwhile, under the scanning electron microscope, no visible influence of the neutron radiation on the spore configuration was detected even if the dose was increased to 4 kGy. The content and distribution of DNA double-strand breaks induced by neutron radiation at different doses were measured and quantified by pulsed- field gel electrophoresis （PFGE）. Further analysis of the DNA release percentage （PR）, the DNA breakage level （L）, and the average molecular weight, indicated that DNA fragments were obvi- ously distributed around the 5 kb regions at different radiation doses, which suggests that some points in the DNA molecule were sensitive to neutron radiation. Both PR and L varied regularly to some extent with the increase in radiation dose. Thus neutron radiation has a high sterilization power, and can induce falling enzyme activity and DNA breakage in Bacillus subtilis spores

Dynamical Evolution of Gamma-Ray Burst Remnants with Evolving Radiative Efficiency

In previous works, a generic dynamical model has been suggested by Huang. et al., which is shown to be correct for both adiabatic and radiative blast-waves, in both ultra-relativistic and non-relativistic phases. In deriving their equations, Huang et al. have assumed that the radiative efficiency of the fireball is constant. They then applied their model directly to realistic cases where the radiative efficiency evolves with time. In this paper, we abandon the above assumption and re-derive a more accurate dynamical equation for gamma-ray burst remnants. Numerical results show that the model presented by Huang et al. is accurate enough in general cases.

Temporal Trends in Radiation Dose Associated with Coronary Computed Tomography Angiography

Background: In 2010, the International Atomic Energy Agency launched the “3A’s campaign” as an effective tool for primary cancer prevention. In 2011, the American Association of Physicists in Medicine recommended the size specific dose estimate (SSDE). Objectives: To audit doses of Coronary CT Angiography (Coronary CTA) in tertiary care referral center. Methods: We reviewed 998 consecutive Coronary CTA (from 2007 to 2012). Doses (CTDIvol mGy), DLP (mGy*cm), effective dose (DLP*0.014, mSv) were on-line archived. SSDE was estimated retrospectively. Appropriateness score was evaluated for exams performed from the 2010. Results: Overall median dose per Coronary CTA was 49.7 mGy for CTDIvol, 55.5 mGy for SSDE, 994.96 mGy*cm for DLP, 13.9 mSv for effective dose. Median DLP decreased over time (1452.94 in 2007, 1605.56 in 2008, 1113.49 in 2009, 759.99 in 2010, 448.61 in 2011 and 497.88 mGy*cm in 2012, p < 0.0001). SSDE was proportional to the size dependent factor (SDF);in patients with SDF > 1 (88%) CTDIvol underestimated SSDE (48.49 vs 57.19 mGy), whilst in patients with SDF < 1 (12%) CTDIvol overestimated SSDE (56.46 vs 50.3 mGy). Scans were appropriate in 58%, uncertain in 24%, and inappropriate in 18% of cases. Doses were similar in appropriate, uncertain or inappropriate examinations and in excellent-to-good (81%) vs. sufficient-to-poor (19%) image quality exams. Conclusions: Coronary CTA reference doses can be very misleading. SSDE can allow individual technique optimization. The dose is similar in appropriate and inappropriate examinations, and unrelated to image quality. The rate of inappropriate examinations is still too high even after dissemination of guidelines.

Channeling in Bent Crystallites: A New Method to Enhance the Radiation Shielding Efficiency

A new method is proposed here aiming at designing a shielding wall with the efficiency significantly higher than that of traditional designs. This new design arises from the idea of using channeling in multilayered shielding wall structure, each layer composed of bent crystallites distributed in a way that each layer covers a small section of 2π angular range of which wall is exposed. Part of the incident charged particles will get channeled in bent crystallites in each layer. Bending of channeled particles in bent crystallites will change their directions in the wall increasing their path lengths in the wall which would enhance its shielding efficiency for charged particle radiations. Proposed design is useful for radiation shielding in fission power plants, future fusion reactors and air travel.

Sterilization complexes based on ILU-type electron accelerators

This paper describes the industrial electron accelerators of the ILU type and their usage for sterilization.The ILU machines produced by Budker Institute of Nuclear Physics have energy range of 0.8-10 MeV and beam power up to 100 kW,and they are working in industries all over the world.The ILU-10 and ILU-14 machines are described as well as the industrial sterilization facility based on ILU-6,ILU-10 and ILU-14 machines.

Ultra-Violet (UV): A Good Bacterial Sterilizer?

Introduction: The aim of this study was to improve the DISTER-UV and to perform microbiological quality control at the biomedical laboratory of the West African Polytechnic University from January 2022 to November 2022. Methodology: During this eleven-month prospective study, we set up a quality control device (QCD). For microbiological quality control, we performed different cultures of bacteria with different bacteriological and morphological characteristics at T0 (no sterilization) and at T30 (after 30 minutes of sterilization under DISTER-UV). Results: After the realization, the DCQ attached to the DISTER-UV1 allows to display of the UV wavelength present in the light box. This device also displays and alerts when the UV intensity emitted by the lamps is below 250 nm. During microbiological quality control, the cultures carried out at T30 and incubated for 24 hours did not reveal any bacterial colonies. This shows the bactericidal character of DISTER-UV-2. Conclusion: The improvement and the microbiological quality control allowed us to switch from DISTER-UV1 (without sensor) to DISTER-UV-2 (with sensor or DCQ). The biological control allowed us to affirm that the DISTER-UV-2 is bactericidal.

医疗器械用热塑性弹性体的制备及耐辐照性能

采用具有耐辐照特性的溴化聚(异丁烯-对甲基苯乙烯)(BIMS)为基体橡胶,与苯乙烯-乙烯-丁烯-苯乙烯嵌段共聚物(SEBS)共混,以烷基苯酚二硫化物作为硫化交联剂,并配合一种生物基增塑剂,采用动态硫化工艺,制备了一种医疗器械用耐辐照动态硫化热塑性弹性体(TPV)。通过对不同剂量辐照后TPV的基本理化性质、顶空气相色谱、红外图谱、热稳定性、动态机械性能和力学性能对比分析研究发现,在辐照灭菌(≤40 kGy)后,产品性能未发生变化,可满足常规医疗器械用弹性体制品对耐辐照性能的要求。

基于文献计量学的辐照杀菌研究进展及其行业发展现状分析

该文基于文献计量学,应用VOSviewer 1.6.20软件,对1990-2023年中国知网(CNKI)数据库、Web of Science(WOS)数据库中辐照杀菌在食品科学领域141篇中文文献和1337篇英文文献进行计量统计和可视化分析,并借助专利搜索工具SooPAT及商业查询平台天眼查对辐照杀菌专利申请状况及企业发展现状进行分析。结果表明,辐照杀菌领域发文量自2000年后基本呈逐年上升趋势;美国、中国、英国为主要发文国家;《核农学报》、《Applied and Environmental Microbiology》发文量较多;中国国家自然科学基金为扶持力度最大的基金项目;中文核心作者朱佳廷、冯敏、刘春泉之间联系紧密,WOS数据库发文量最多的作者为THAYER D W;关键词共现分析发现辐照剂量及辐照杀菌应用是研究热点。辐照杀菌领域的申请、发明专利分别为1997件、1367件;目前国内现存辐照杀菌相关公司23家。