Isomeric fluorescence sensors for wide range detection of ionizing radiations

In order to achieve a wider range of ionizing radiations detection,novel fluorescence sensing materials have been developed that utilize the fluorescence enhancement phenomenon caused by the intramolecular photoinduced electron transfer(PET)effect.Two perylene diimide isomers PDI-P and PDI-B were designed and synthesized,and their molecular structures were characterized by high-resolution Fourier transform mass spectrometry(HRMS),nuclear magnetic resonance hydrogen and carbon spectroscopy(~1H and~(13)C NMR).The interaction between ionizing radiation and fluorescent molecules was simulated by HCl titration.The results show that combining PDIs and HCl can improve fluorescence through the retro-PET process.Despite the similarities in chemical structures,the fluorescent enhancement multiple of PDI-B with aromatic amine as electron donor is much higher than that of PDI-P with alkyl amine.In the direct irradiation experiments of ionizing radiation,the emission enhancement multiples of PDI-P and PDI-B are 2.01 and 45.4,respectively.Furthermore,density functional theory(DFT)and time-dependent density functional theory(TDDFT)calculations indicate that the HOMO and HOMO-1 energy ranges of PDI-P and PDI-B are 0.54 e V and 1.13 e V,respectively.A wider energy range has a stronger driving force on electrons,which is conducive to fluorescence quenching.Both femtosecond transient absorption spectroscopy(fs-TAS)and transient fluorescence spectroscopy(TFS)tests show that PDI-B has shorter charge separation lifetime and higher electron transfer rate constant.Although both isomers can significantly reduce LOD during PET process,PDI-B with aromatic amine has a wider detection range of 0.118—240 Gy due to its larger emission enhancement,which is a leap of three orders of magnitude.It breaks through the detection range of gamma radiation reported in existing studies,and provides theoretical support for the further study of sensitive and effective new materials for ionizing radiation detection.

Distinct MLT asymmetry of auroral kilometric radiation observed by the FAST satellite

Auroral Kilometric Radiation (AKR) is a common radio emission,which can contribute to the magnetosphere-ionosphereatmosphere co u pling.Similar emissions have been observed in all magnetic planet magnetospheres of the solar system.In this study,using observations from the FAST satellite from 30 August 1996 to 9 September 2001,the distribution of AKR in altitude=500-4500 km and invariant latitude (|ILAT|)=60°-80°has been analyzed.63045 AKR samples have been identified with~48%(52%) samples on the dayside (nightside).Of considerable interest,there is a distinct MLT asymmetry with the high occurrence rate in MLT=05-08 and 18-22(02-05 and 12-17) in the northern (southern) hemisphere.The distinct MLT asymmetry is associated with the direction of Bxof the interplaneta ry magnetic field.In addition,the occurrence rate on the nightside clearly increases as the AE^(*) index increases.This study further enriches the information and understanding of AKR in the magnetosphere as well as other similar radio emissions.

Total Ionizing Dose Radiation Effects on MOS Transistors with Different Layouts

Both nMOS and pMOS transistors with two-edged and multi-finger layouts are fabricated in a standard commercial 0.6μm CMOS/bulk process to study their total ionizing dose （TID） radiation effects. The leakage current, threshold voltage shift, and transconductance of the devices are monitored before and after T-ray irradiation. Different device bias conditions are used during irradiation. The experiment results show that TID radiation effects on nMOS devices are very sensitive to their layout structures. The impact of the layout on TID effects on pMOS devices is slight and can be neglected.

Laser Device for the Protection of Biological Objects from the Damaging Action of Ionizing Radiation

Laser irradiation device for the protection of biological objects from the action of ionizing radiation to be used in practice has been manufactured （invention patent RU 2 428 228 C2）. Research of the action of y-radiation itself as well as of the combined action of laser devices on survival, weight, skin and the general mitotic index of the bone marrow cells （mitotic index of all nucleus-containing cells of the bone marrow） of C57BL/6 experimental young mice was carried out. The mice were irradiated with ionizing （whole body irradiation） and laser radiation, separately one by one in a special frame device. Laser radiation in the dose 1 mJ/cm^2 irradiated only the back of a mouse, or both the back and the abdomen of mice. In case of combined irradiation of mice, the time interval between two types of irradiation did not exceed 30 min. First, the mice were exposed to y-radiation then to laser radiation. The method of the laser radiation-protection of biological subjects contributes to an increase in the viability of mice, prevents the damages of skin and also increases the mitotic activity of mice bone marrow cells.

Genotypic characteristics of resistant tumors to pre-operative ionizing radiation in rectal cancer

Due to a wide range of clinical response in patients un-dergoing neo-adjuvant chemoradiation for rectal cancer it is essential to understand molecular factors that lead to the broad response observed in patients receiving the same form of treatment.Despite extensive research in this field,the exact mechanisms still remain elusive.Data raging from DNA-repair to specific molecules lead-ing to cell survival as well as resistance to apoptosis have been investigated.Individually,or in combination,there is no single pathway that has become clinically applicable to date.In the following review,we describe the current status of various pathways that might lead to resistance to the therapeutic applications of ionizing radiation in rectal cancer.

Study of a Portable Experimental Set for the Monitoring of Ionizing Radiation in the Tropical Region of Brazil

The Geiger is a proportional counter that detects the ambient ionizing radiation using a sensor tube and an associated electronics that allows feeding the desired voltage to the tube and acquiring the data in a certain time interval. With a sensor tube of Chinese and Russian origin and associated electronics based on the Arduino system, an experimental set of very low cost and easy handling for the monitoring of the local environmental ionizing radiation was set up. The main objective of this work is to disseminate this very low cost technique for the environmental study in secondary schools in Brazil.

Dynamics of Environmental Ionizing Radiation between May to September 2016 in the Region of S^o Jos~ dos Campos, SP, Brazil

Measurements of gamma radiation （200 keV to 10 MeV） were performed between May 25 to September 30 2016 at ITA （Technological Institute of Aeronautics） in Sao Jose dos Campos, SP, Brazil. Detector and associated electronics were previously calibrated in the laboratory of ITA using radioactive sources Cs-137, Po-210 and Sr-90. These sources provide gamma-ray energies in 0.662 keV alpha particles of 5.4 MeV and 0.90 keV electrons, respectively. Detector is a scintillator Sodium Iodide activated with Thallium [NaI（Tl）] associated to a photomultiplier and electronic devices which gather, store, distribute and structure data so users can analyze them. During the period of May-September, the experimental set was installed in an open room on a tower 25 meters above the ground. Measurements indicated variations of ionizing radiation in function of dry weather, rain, cold fronts passes and presence of fog in the area; the sample time interval was minute by minute. This study discusses the analysis and the dynamics of how to measure meteorological parameters using an ionizing radiation system.

Selective internal radiation therapy segmentectomy:A new minimally invasive curative option for primary liver malignancies?

Transarterial radioembolization or selective internal radiation therapy(SIRT)has emerged as a minimally invasive approach for the treatment of tumors.This percutaneous technique involves the local,intra-arterial delivery of radioactive microspheres directly into the tumor.Historically employed as a palliative measure for liver malignancies,SIRT has gained traction over the past decade as a potential curative option,mirroring the increasing role of radiation segmentectomy.The latest update of the BCLC hepatocellular carcinoma guidelines recognizes SIRT as an effective treatment modality comparable to other local ablative methods,particularly well-suited for patients where surgical resection or ablation is not feasible.Radiation segmentectomy is a more selective approach,aiming to deliver high-dose radiation to one to three specific hepatic segments,while minimizing damage to surrounding healthy tissue.Future research efforts in radiation segmentectomy should prioritize optimizing radiation dosimetry and refining the technique for super-selective administration of radiospheres within the designated hepatic segments.

Computer-assisted formulas predicting cancer mortality risk after exposure to acute low dose ionizing radiation in humans

A clear relationship between dose of radiation and mortality in humans is still not known because of lack of human data that would enable to determine human tolerance in total body irradiation. Human data for analysis have been primarily from radiation accidents, radiotherapy and the atomic bomb victims. A general formula that predicts mortality probability as a function of dose rate and duration of exposure to acute high dose ionizing radiation in humans was published by the author, applying the “probacent” model to the reported data on animal-model-predicted dose versus mortality. In this study, the “probacent” model is applied to the data on dose versus cancer mortality risk, published by the United Nations (UNSCEAR, 2010) and other investigators to construct general formulas expressing a relationship between dose and solid cancer or leukemia mortality probability after exposure to acute low dose ionizing radiation in humans. There is a remarkable agreement between formula-derived and published values of dose and solid cancer or leukemia mortality probability (p > 0.99). The general formula might be helpful in preventing radiation hazard and injury in acute low dose ionizing radiation, and for safety in radiotherapy.

Bioflavonoids as Important Component of Biological Protection from Ionizing Radiation

New advances in the area of deciphering the mechanism for a possible modification of the biological effects of radiation exposure at the genetic level make it possible to distinguish the group of radiation protective agents having their own specific features in the implementation of their beneficial effects. The mechanism of the radioprotective action of bioflavonoids is worthy of a detailed analysis in view of their great biological importance. Radiobiological studies show that antioxidants can reduce the radiation damage to membranes and favor more adequate energy dependent adaptive and reparative processes after the exposure to radiation. Bioflavonoids are significant component of “biological protection” for a enhance of resistance of the body to environmental factors that are adverse for human health, including ionizing radiation, with reducing the risk of carcinogenic effects and decreasing the biological age. The best practical value of bioflavonoids, can be considered as the agents for prophylaxis against the development of oxidative stress. These are the reasons why the administration of natural antioxidants have a pathogenetic justification for exposures to chronic (months, years) low-rate-dose ionizing radiation. These agents were previously and are currently being developed for use during long-term, low-ratedose exposures to radiation, under conditions of long space missions. Acting as low-dose stressors through a hormetic mechanism and a “substrate” support of adaptive shifts radiomodulators results in an increase in the antioxidant defense of the body and the rearrangement of its functioning in the new environment with the modulation of gene expression of antioxidant response elements by activation of Nrd2/KeapI and Sirtuin/FoxO pathways and a decrease in the transcription factor NF-κB.

Role of radiation therapy in gastric adenocarcinoma

Outcomes in patients with gastric cancer in the United States remain disappointing, with a five-year overall survival rate of approximately 23%. Given high rates of local-regional control following surgery, a strong rationale exists for the use of adjuvant radiation therapy. Randomized trials have shown superior local control with adjuvant radiotherapy and improved overall survival with adjuvant chemoradiation. The benefit of adjuvant chemoradiation in patients who have undergone D2 lymph node dissection by an experienced surgeon is not known, and the benefit of adjuvant radiation therapy in addition to adjuvant chemotherapy continues to be defined. In unresectable disease, chemoradiation allows long-term survival in a small number of patients and provides effective palliation. Most trials show a benefit to combined modality therapy compared to chemotherapy or radiation therapy alone. The use of pre-operative, intra-operative, 3D conformal, and intensity modulated radiation therapy in gastric cancer is promising but requires further study. The current article reviews the role of radiation therapy in the treatment of resectable and unresectable gastric carcinoma, focusing on current recommendations in the United States.

Effect of Ionizing Radiation on the Expression of p16, CyclinDI and CDK4 in Mouse Thymocytes and Splenocytes

Objective To investigate the effect of ionizing radiation on the expression of p16, CyclinDl, and CDK4 in mouse thymocytes and splenocytes. Methods Fluorescent staining and flow cytometry analysis were employed for the measurement of protein expression. Results In time course experiments, it was found that the expression of p16 protein was significantly increased at 8, 24, and 48 h for thymocytes (P<0.05, P<0.01, and P<0.05, respectively) and at 24 h for splenocytes (P<0.05) after whole body irradiation (WBI) with 2.0 Gy X-rays. However, the expression of CDK4 protein was significantly decreased from 8 h to 24 h for thymocytes (P<0.05,P<0.01) and from 8 h to 72 h for splenocytes (P<0.05-P<0.01). In dose effect experiments, it was found that the expression of p16 protein in thymocytes and splenocytes was significantly increased at 24 h after WBI with 1.0, 2.0, and 4.0 Gy (P<0.05-P<0.01), whereas the expression of CDK4 protein was significantly decreased with 2.0Gy for thymocytes (P<0.05) and 0.5-6.0 Gy for splenocytes (P<0.05-P<0.01). Results also showed that the expression of CyclinDl protein decreased markedly in both thymocytes and splenocytes after exposure. Conclusion The results indicate that the expression of p 16 protein in thymocytes and splenocytes can be induced by ionizing radiation, and the p16-CyclinD1/CDK4 pathway may play an important role for G1 arrest of thymocytes induced by X-rays.

Combination of genistein with ionizing radiation on andro-gen-independent prostate cancer cells

Aim: To study the effect of the combined use of genistein and ionizing radiation (IR) on prostate DU145 cancer cells. Methods: DU145, an androgen-independent human prostate cancer cell line, was used in the experiment. Clonogenic assay was used to compare the survival of DU145 cells after treatments with genistein alone and in combination with graded IR. Apoptosis was assayed by DNA ladder and TUNEL stain. Cell cycle alterations were observed by flow cytometry and related protein expressions by immunoblotting. Results: Clonogenic assay demonstrated that genistein, even at low to medium concentrations, enhanced the radiosensitivity of DU145 cells. Twenty-four hours after treatment with IR and/or genistein, apoptosis was mainly seen with genistein at high concentrations and was minimally related to IR. At 72 h, apoptosis also occurred in treatment with lower concentration of genistein, especially when combined with IR. While both IR and genistein led to G2/M cell cycle arrest, combination of them further increased the DU145 cells at G2/M phase. This Gz/M arrest was largely maintained at 72 h, accompanied by increasing apoptosis and hyperdiploid cell population. Cell-cycle related protein analysis disclosed biphasic changes in cyclin B1 and less dramatically cdc-2, but stably elevated p21cipl levels with increasing genistein concentrations. Conclusion: Genistein enhanced the radiosensitivity of DU145 prostate cancer cells. The mechanisms might be involved in the increased apoptosis, prolonged cell cycle arrest and impaired damage repair.

Radiation of a TM mode from an open end of a three-layer dielectric capillary

Modern trends in beam-driven radiation sources include the interaction of Cherenkov wakefields in open-ended circular waveguides with complicated dielectric linings, with a three-layer dielectric capillary recently proposed to reduce radiation divergence being a representative example [Opt. Lett. 45 5416(2020)]. We present a rigorous approach that allows for an analytical description of the electromagnetic processes that occur when the structure is excited by a single waveguide TM mode. In other words, the corresponding canonical waveguide diffraction problem is solved in a rigorous formulation. This is a continuation of our previous papers which considered simpler cases with a homogeneous or two-layer dielectric filling. Here we use the same analytical approach based on the Wiener–Hopf–Fock technique and deal with the more complicated case of a three-layer dielectric lining. Using the obtained rigorous solution, we discuss the possibility of manipulating the far-field radiation pattern using a third layer made of a low permittivity material.

Effect of ionizing radiation on transcription of colorectal cancer MDR1 gene of HCT-8 cells

Objective:To discuss effect of ionizing radiation on transcription of colorectal cancer multidrug resistance(MDR) 1 gene of HCT-8 cells.Methods:Total RNA was extracted by guanidine thiocyanate one-step method.Northern blot was applied to detect transcription level of MDR1 gene.The expression of P-gp protein was detected by flow cytometry.Results:The expression of MDRl of normal colorectal cancer HCT-8 cells was low.It was increased by 8.35 times under stimulus with 2 Gy.When treated with low doses in advance,high expressed MDR was decreased significantly under 0.05,0.1 Gy,which was 69.00%,62.89%in 2 Cy group and 5.77 times,5.25 times in sham irradiation group.No obvious difference was detected between(0.2+2) Gy group and 2 Gy group.Compared with sham irradiation group,the percentage of P-gp positive cells after radiation of a high 2 Gy dose was increased significantly(P【0.01).When treated with high radiation dose following low radiation dose(0.05 Gy,0.1 Gy) in advance,the percentage of P-gp positive cells were also increased significantly.The percentage of P-gp positive cells were increased obviously in 0.2 Gy and 2 Gy groups.Compared with simple high radiation 2 Gy group,the percentage of P-gp positive cells was decreased significantly(P【0.05).Conclusions: Low radiation dose can reverse multidrug resistance of colorectal cancer cells caused by high radiation dose.

Effect of gamma-ray radiation on defect engineering and photocatalytic properties of boron nitride nanosheets

The development of low-cost,abundant,and efficient non-metal catalysts has always been a research focus on photocatalytic hydrogen evolution reactions.Boron nitride nanosheet(BNNS),which is a promising non-metallic two-dimensional material,possesses remarkable properties.However,its inherently wide bandgap significantly limits their potential for visible-light-responsive catalysis,and conventional chemical methods struggle to overcome this limitation.In this study,we employed high-energy ionizing radiation to precisely regulate defect formation in BNNS at ambient temperature and pressure.The results showed that gamma-ray radiation markedly enhanced the efficiency of photocatalytic hydrogen production of the irradiated BNNS with increasing absorbed dose.The maximum hydrogen production rate of the samples reached 1033.7μmol/(g·h),which represents an increase of almost two orders of magnitude compared to commercial BNNS.The structural characterization also confirmed that the introduction of three-boron-center defects results in forming intermediate energy levels and improving the charge carrier separation efficiency of BNNS.This transformation converts BNNS from a wide bandgap semiconductor to a visible-light-responsive catalyst.This work not only provides a novel approach for the application of BNNS in visible-light photocatalysis,but also demonstrates the unique role of radiation technology in quantitatively regulating defects and improving catalytic activity.

Surveying ionizing radiations in real time using a smartphone

Surveying ionizing radiations of the surrounding with a smartphone provides a low-cost and convenient utility for the general public. We developed a smartphone application(App) that uses the built-in camera with a CMOS sensor and a radiation signal extraction algorithm.After a calibration through a series of radiation exposures,the App could display radiation dose rate and cumulative dose in real time without requiring covering the camera lens. A smartphone with this App can be used as a fast survey tool for ionizing radiations.

The Effect of a Monatomic Layer on a Surface on the Transition Radiation

The transition radiation of a charged particle crossing the interface of two media having a monatomic impurity layer is investigated. It is shown that at sliding angles of incidence of a particle on the boundary of the media, the transition radiation is mainly determined by the properties of the surface layer. The possibility of using transition radiation to study the surface of substances is discussed. In addition, due to the hard radiation present in space, this research may be important for the use of light monoatomic layers as a material for satellite antennas, “solar sails” and cover layers in a future space (interstellar) mission.

Extraction of the key infrared radiation temperature features concerning stress and crack evolution of loaded rocks

The infrared radiation temperature(IRT)variation concerning stress and crack evolution of rocks is a critical focus in rock mechanics domain and engineering disaster warning.In this paper,a methodology to extract the key IRT features related to stress and crack evolution of loaded rocks is proposed.Specifically,the wavelet denoising and reconstruction in thermal image sequence(WDRTIS)method is employed to eliminate temporal noise in thermal image sequences.Subsequently,the adaptive partition temperature drift correction(APTDC)method is introduced to alleviate temperature drift.On this basis,the spatial noise correction method based on threshold segmentation and adaptive median filtering(OTSU-AMF)is proposed to extract the key IRT features associated with microcracks of loaded rocks.Following temperature drift correction,IRT provides an estimation of the thermoelastic factor in rocks,typically around 5.29×10^(-5) MPa^(-1) for sandstones.Results reveal that the high-temperature concentrated region in cumulative thermal images of crack evolution(TICE)can elucidate the spatiotemporal evolution of localized damage.Additionally,heat dissipation of crack evolution(HDCE)acquired from TICE quantifies the progressive failure process of rocks.The proposed methodology enhances the reliability of IRT monitoring results and provides an innovative approach for conducting research in rock mechanics and monitoring engineering disasters.

Autophagic cell death induced by reactive oxygen species is involved in hyperthermic sensitization to ionizing radiation in human hepatocellular carcinoma cells

AIM To investigate whether autophagic cell death is involved in hyperthermic sensitization to ionizing radiation in human hepatocellular carcinoma cells, and to explore the underlying mechanism.METHODS Human hepatocellular carcinoma cells were treated with hyperthermia and ionizing radiation. MTT and clonogenic assays were performed to determine cell survival. Cell autophagy was detected using acridine orange staining and flow cytometric analysis, and the expression of autophagy-associated proteins, LC3 and p62, was determined by Western blot analysis. Intracellular reactive oxygen species(ROS) were quantified using the fluorescent probe DCFH-DA.RESULTS Treatment with hyperthermia and ionizing radiation significantly decreased cell viability and surviving fraction as compared with hyperthermia or ionizing radiation alone. Cell autophagy was significantly increased after ionizing radiation combined with hyperthermia treatment, as evidenced by increased formation of acidic vesicular organelles, increased expression of LC3 II and decreased expression of p62. Intracellular ROS were also increased after combined treatment with hyperthermia and ionizing radiation. Pretreatment with N-acetylcysteine, an ROS scavenger, markedly inhibited the cytotoxicity and cell autophagy induced by hyperthermia and ionizing radiation.CONCLUSION Autophagic cell death is involved in hyperthermic sensitization of cancer cells to ionizing radiation, and its induction may be due to the increased intracellular ROS.