Seed Priming by Low-Dose Radiation Improves Growth of Lactuca sativa and Valerianella locusta.

Valerian salad and lettuce are edible species that are easy to grow rapidly, and have traits useful for commercial purposes. The consumption of these species is increasing worldwide for their nutritional properties. Seed germination and seedling development are critical stages in the life cycle of plants. Seed priming, including the use of high-energy radiation, is a set of techniques based on the idea that low stress levels stimulate plant responses, thereby improving seed germination and plant growth. In this study, we evaluated in hydroponic culture (i) the germination performance; (ii) morphological traits; and (iii) antioxidant and phenol contents at different endpoints in Lactuca sativa and Valerianella locusta that were developed from seeds exposed to X-rays (1 Gy and 10 Gy doses). Under radiation, biomass production increased in both species, especially in lettuce, where also a reduction in the mean germination time occurred. Radiation increased the level of phenols during the first growth weeks, under both doses for lettuce, and only 1 Gy was required for valerian salad. The species-specific responses observed in this research suggest that the use of radiations in seed priming needs to be customized to the species.

Role of the mechanical microenvironment on CD-44 expression of breast adenocarcinoma in response to radiotherapy.

The biological effects of ionizing radiation are exploited in the clinical practice of radiotherapy to destroy tumour cells while sparing the surrounding normal tissue. While most of the radiotherapy research focused on DNA damage and repair, recently a great attention is going to cells' interactions with the mechanical microenvironment of both malignant and healthy tissues after exposure. In fact, the stiffness of the extracellular matrix can modify cells' motility and spreading through the modulation of transmembrane proteins and surface receptors' expression, such as CD-44. CD-44 receptor has held much interest also in targeted-therapy due to its affinity with hyaluronic acid, which can be used to functionalize biodegradable nanoparticles loaded with chemotherapy drugs for targeted therapy. We evaluated changes in CD-44 expression in two mammary carcinoma cell lines (MCF10A and MDA-MB-231) after exposure to X-ray (2 or 10 Gy). To explore the role of the mechanical microenvironment, we mimicked tissues' stiffness with polyacrylamide's substrates producing two different elastic modulus values (0.5 and 15 kPa). We measured a dose dependent increase in CD-44 relative expression in tumour cells cultured in a stiffer microenvironment. These findings highlight a crucial connection between the mechanical properties of the cell's surroundings and the post-radiotherapy expression of surface receptors.

Evaluation of morpho-physiological responses and genotoxicity in Eruca sativa (Mill.) grown in hydroponics from seeds exposed to X-rays.

Due to its potential applications in cultivated plants, ionizing radiation (IR) and its effect on organisms is increasingly studied. Here we measured the effects of ionizing radiation on Eruca sativa by analyzing plants from irradiated seeds (1 and 10 Gy) grown in hydroponics. We measured several morpho-physiological traits and genotoxicity. Radiation stress induced a noticeable variability of the morpho-physiological traits highlighting decreased plant vigor. Shoot length and leaf number were significantly higher in 1 Gy-treated samples, whereas root length was significantly higher in 10 Gy treated plants. Stomata number significantly increased with IR dose, whereas both pigment and Rubisco content decreased under radiation stress. Phenol content significantly increased in 1 Gy treated samples, otherwise from total antioxidants, which were not different from control. Most results could find a feasible explanation in a hormesis-like pattern and in a decreased plant vigor under radiation stress. IR induced genotoxic damage, evaluated by ISSR markers, in 15 day old leaves; specifically, a severe decrease in the genome template stability was observed. However, a partial recovery occurred after 2 weeks, especially under the lowest dose (i.e., 1 Gy), suggesting that DNA damage detection and repair mechanisms are active. Pigment content and genotoxic damage may serve as proxies for evaluating plant responses to IR stress, since they show univocal dose-dependent trends. The use of more checkpoints for analyses and more doses over a wider range, as well as the focus on different metabolites, could help elucidate plant response in terms of morpho-physiological changes.

Use of Thermoluminescence Dosimetry for QA in High-Dose-Rate Skin Surface Brachytherapy with Custom-Flap Applicator.

Surface brachytherapy (BT) lacks standard quality assurance (QA) protocols. Commercially available treatment planning systems (TPSs) are based on a dose calculation formalism that assumes the patient is made of water, resulting in potential deviations between planned and delivered doses. Here, a method for treatment plan verification for skin surface BT is reported. Chips of thermoluminescent dosimeters (TLDs) were used for dose point measurements. High-dose-rate treatments were simulated and delivered through a custom-flap applicator provided with four fixed catheters to guide the Iridium-192 (Ir-192) source by way of a remote afterloading system. A flat water-equivalent phantom was used to simulate patient skin. Elekta TPS Oncentra Brachy was used for planning. TLDs were calibrated to Ir-192 through an indirect method of linear interpolation between calibration factors (CFs) measured for 250 kV X-rays, Cesium-137, and Cobalt-60. Subsequently, plans were designed and delivered to test the reproducibility of the irradiation set-up and to make comparisons between planned and delivered dose. The obtained CF for Ir-192 was (4.96 ± 0.25) µC/Gy. Deviations between measured and TPS calculated doses for multi-catheter treatment configuration ranged from -8.4% to 13.3% with an average of 0.6%. TLDs could be included in clinical practice for QA in skin BT with a customized flap applicator.

The first indoor radon mapping in the Campania region, Italy.

For the first time, a map of the 222Rn gas has been produced in the Campania region, the southern part of Italy, based on the activity concentration measured in indoor environments. This work is part of the radon mitigation policy and complies with the recent Italian Legislative Decree 101/2020, which implements the European Basic Safety Standards, Euratom Directive 59/2013, where Member States must declare areas with elevated levels of indoor radon concentration. The obtained map, divided by Campania municipalities, identifies priority areas with activity concentration values exceeding the reference level of 300 Bq m-3. In addition, an effective statistical analysis of the dataset has been carried out.

Radiation therapy affects YAP expression and intracellular localization by modulating lamin A/C levels in breast cancer.

The microenvironment of breast cancer actively participates in tumorigenesis and cancer progression. The changes observed in the architecture of the extracellular matrix initiate an oncogene-mediated cell reprogramming, that leads to a massive triggering of YAP nuclear entry, and, therefore, to cancer cell proliferation, invasion and probably to increased radiation-resistance. However, it is not yet fully understood how radiotherapy regulates the expression and subcellular localization of YAP in breast cancer cells experiencing different microenvironmental stiffnesses. To elucidate the role of extracellular matrix stiffness and ionizing radiations on YAP regulation, we explored the behaviour of two different mammary cell lines, a normal epithelial cell line (MCF10A) and a highly aggressive and invasive adenocarcinoma cell line (MDA-MB-231) interacting with polyacrylamide substrates mimicking the mechanics of both normal and tumour tissues (∼1 and ∼13 kPa). We report that X-ray radiation affected in a significant way the levels of YAP expression, density, and localization in both cell lines. After 24 h, MCF10A and MDA-MB-231 increased the expression level of YAP in both nucleus and cytoplasm in a dose dependent manner and particularly on the stiffer substrates. After 72 h, MCF10A reduced mostly the YAP expression in the cytoplasm, whereas it remained high in the nucleus of cells on stiffer substrates. Tumour cells continued to exhibit higher levels of YAP expression, especially in the cytoplasmic compartment, as indicated by the reduction of nuclear/cytoplasmic ratio of total YAP. Then, we investigated the existence of a correlation between YAP localization and the expression of the nuclear envelope protein lamin A/C, considering its key role in modulating nuclear deformability and changes in YAP shuttling phenomena. As supposed, we found that the effects of radiation on YAP nucleus/cytoplasmic expression ratio, increasing in healthy cells and decreasing in tumour ones, were accompanied by lower and higher lamin A/C levels in MCF10A and MDA-MB-231 cells, respectively. These findings point to obtain a deeper knowledge of the role of the extracellular matrix and the effects of X-rays on YAP and lamin A/C expression that can be used in the design of doses and timing of radiation therapy.

Characterization of Thermoluminescent Dosimeters for Neutron Dosimetry at High Altitudes.

Neutrons constitute a significant component of the secondary cosmic rays and are one of the most important contributors to natural cosmic ray radiation background dose. The study of the cosmic ray neutrons' contribution to the dose equivalent received by humans is an interesting and challenging task for the scientific community. In addition, international regulations demand assessing the biological risk due to radiation exposure for both workers and the general population. Because the dose rate due to cosmic radiation increases significantly with altitude, the objective of this work was to characterize the thermoluminescent dosimeter (TLDs) from the perspective of exposing them at high altitudes for longtime neutron dose monitoring. The pair of TLD-700 and TLD-600 is amply used to obtain the information on gamma and neutron dose in mixed neutron-gamma fields due to the present difference in 6Li isotope concentration. A thermoluminescence dosimeter system based on pair of TLD-600/700 was characterized to enable it for neutron dosimetry in the thermal energy range. The system was calibrated in terms of neutron ambient dose equivalent in an experimental setup using a 241Am-B radionuclide neutron source coated by a moderator material, polyethylene, creating a thermalized neutron field. Afterward, the pair of TLD-600/700 was exposed at the CERN-EU High-Energy Reference Field (CERF) facility in Geneva, which delivers a neutron field with a spectrum similar to that of secondary cosmic rays. The dosimetric system provided a dose value comparable with the calculated one demonstrating a good performance for neutron dosimetry.

COVID-19 and the Additional Radiological Risk during the Lockdown Period in the Province of Naples City (South Italy).

The lockdown restrictions, as a first solution to contain the spread of the COVID-19 pandemic, have affected everyone's life and habits, including the time spent at home. The latter factor has drawn attention to indoor air quality and the impact on human health, particularly for chemical pollutants. This study investigated how the increasing time indoor influenced exposure to natural radioactive substances, such as radon gas. To calculate the radiological risk, we considered the most consolidated indices used for radiation protection: annual effective dose, excess lifetime cancer risk, and the lung cancer case. Furthermore, two different exposure times were considered: pre-lockdown and post-lockdown. The lockdown increased the indoor exposure time by 4% and, consequently, the radiological risk factors by 9%. Furthermore, the reference value of 300 Bq/m3, considered acceptable for human radiation protection, may need to be lowered further in the case of conditions similar to those of the lockdown period.

Characterization of Hyaluronic Acid-Coated PLGA Nanoparticles by Surface-Enhanced Raman Spectroscopy.

Nanoparticles (NPs) coated with hyaluronic acid (HA) seem to be increasingly promising for targeted therapy due to HA chemical versatility, which allows them to bind drugs of different natures, and their affinity with the transmembrane receptor CD-44, overexpressed in tumor cells. However, an essential aspect for clinical use of NPs is formulation stability over time. For these reasons, analytical techniques capable of characterizing their physico-chemical properties are needed. In this work, poly(lactide-co-glycolide) (PLGA) NPs with an average diameter of 100-150 nm, coated with a few 10 s of nm of HA, were synthesized. For stability characterization, two complementary investigative techniques were used: Dynamic Light Scattering (DLS) and Surface-Enhanced Raman Scattering (SERS) spectroscopy. The first technique provided information on size, polidispersity index, and zeta-potential, and the second provided a deeper insight on the NP surface chemicals, allowing distinguishing of HA-coated NPs from uncoated ones. Furthermore, in order to estimate formulation stability over time, NPs were measured and monitored for two weeks. SERS results showed a progressive decrease in the signal associated with HA, which, however, is not detectable by the DLS measurements.

Pietra Leccese and Other Natural Stones in Puglia Region: A New Category of Building Materials for Radiation Protection?

In this paper, an in-depth and systematic study of the radiological characterization of three types of Puglia region natural limestones (Pietra Leccese, Pietra Mazzara and Carparo) was carried out. The investigation was performed by XRF spectroscopy for a chemical analysis, and gamma spectroscopy of the specific activity concentration of natural radionuclides 226Ra, 232Th, and 40K. Although the limestone does not fall within the category included by Italian Legislative Decree 101/2020, the gamma index was calculated using the results of the gamma spectroscopy measurements. For Pietra Mazzara and Carparo stones, the gamma index was found to be less than the reference value; conversely Pietra Leccese was found to be higher. To obtain a more complete evaluation of the external exposure, radium equivalent activity and external radiation hazard were calculated for all analyzed stones. The results suggest the need to broadly consider the radiological risk for these stones, and for limestone more generally, when used as a building material.

Cytoskeleton Response to Ionizing Radiation: A Brief Review on Adhesion and Migration Effects.

The cytoskeleton is involved in several biological processes, including adhesion, motility, and intracellular transport. Alterations in the cytoskeletal components (actin filaments, intermediate filaments, and microtubules) are strictly correlated to several diseases, such as cancer. Furthermore, alterations in the cytoskeletal structure can lead to anomalies in cells' properties and increase their invasiveness. This review aims to analyse several studies which have examined the alteration of the cell cytoskeleton induced by ionizing radiations. In particular, the radiation effects on the actin cytoskeleton, cell adhesion, and migration have been considered to gain a deeper knowledge of the biophysical properties of the cell. In fact, the results found in the analysed works can not only aid in developing new diagnostic tools but also improve the current cancer treatments.

Radon Survey in Bank Buildings of Campania Region According to the Italian Transposition of Euratom 59/2013.

222Rn gas represents the major contributor to human health risk from environmental radiological exposure. In confined spaces radon can accumulate to relatively high levels so that mitigation actions are necessary. The Italian legislation on radiation protection has set a reference value for the activity concentration of radon at 300 Bq/m3. In this study, measurements of the annual radon concentration of 62 bank buildings spread throughout the Campania region (Southern Italy) were carried out. Using devices based on CR-39 solid-state nuclear track detectors, the 222Rn level was assessed in 136 confined spaces (127 at underground floors and 9 at ground floors) frequented by workers and/or the public. The survey parameters considered in the analysis of the results were: floor types, wall cladding materials, number of openings, door/window opening duration for air exchange. Radon levels were found to be between 17 and 680 Bq/m3, with an average value of 130 Bq/m3 and a standard deviation of 120 Bq/m3. About 7% of the results gave a radon activity concentration above 300 Bq/m3. The analysis showed that the floor level and air exchange have the most significant influence. This study highlighted the importance of the assessment of indoor radon levels for work environments in particular, to protect the workers and public from radon-induced health effects.

Adhesion and Migration Response to Radiation Therapy of Mammary Epithelial and Adenocarcinoma Cells Interacting with Different Stiffness Substrates.

The structural and mechanical properties of the microenvironmental context have a profound impact on cancer cell motility, tumor invasion, and metastasis formation. In fact, cells react to their mechanical environment modulating their adhesion, cytoskeleton organization, changes of shape, and, consequently, the dynamics of their motility. In order to elucidate the role of extracellular matrix stiffness as a driving force in cancer cell motility/invasion and the effects of ionizing radiations on these processes, we evaluated adhesion and migration as biophysical properties of two different mammary cell lines, over a range of pathophysiological stiffness (1-13 kPa) in a control condition and after the exposure to two different X-ray doses (2 and 10 Gy, photon beams). We concluded that the microenvironment mimicking the normal mechanics of healthy tissue has a radioprotective role on both cell lines, preventing cell motility and invasion. Supraphysiological extracellular matrix stiffness promoted tumor cell motility instead, but also had a normalizing effect on the response to radiation of tumor cells, lowering their migratory capability. This work lays the foundation for exploiting the extracellular matrix-mediated mechanism underlying the response of healthy and tumor cells to radiation treatments and opens new frontiers in the diagnostic and therapeutic use of radiotherapy.

Dose-Response of TLD-100 in the Dose Range Useful for Hypofractionated Radiotherapy.

PURPOSE: The aim of the study was to exploit the feasibility of thermoluminescent dosimeters (TLDs) in radiation therapy techniques in which high dose per fraction is involved. METHODS: Dose-response of TLD-100 (LiF: Mg, Ti) was investigated in both 6-MV photon and 6-MeV electron beams. The element correction factor (ECF) generation method was applied to check the variability of the TLDs response. Two batches of 50 TLDs were divided into groups and exposed in the dose range 0 to 30 Gy. Regression analysis was performed with both linear and quadratic models. For each irradiation beam, the calibration curves were obtained in 3 dose range 0 to 8 Gy, 0 to 10 Gy, and 0 to 30 Gy. The best-fitting model was assessed by the Akaike Information Criterion test. RESULTS: The ECF process resulted a useful tool to reduce the coefficients of variation from original values higher than 5% to about 3.5%, for all the batches exposed. The results confirm the linearity of dose-response curve below the dose level of 10 Gy for photon and electron beam and the supralinear trend above. CONCLUSION: The TLDs are suitable dosimeters for dose monitoring and verification in radiation treatment involving dose up to 30 Gy in a single fraction.

New Eye Lens Dose Limit: Status of Knowledge in Campania Hospitals.

The International Commission on Radiation Protection (ICRP) in 2011 recommended the lowering of the annual eye lens dose limit from 150 mSv/year to 20 mSv/year in order to reduce the risk of X-ray-induced lens opacity in medical staff. The purpose of this study was to assess the status of knowledge of the new eye lens dose limit and of the radioprotection culture among operators. To this end, a questionnaire was administered to physicians, X-ray technicians, and nurses working in five hospitals of the Campania region, Italy. A total of 64 questionnaires were collected in the hospital departments in which procedures involving ionizing radiation were routinely performed. The data analyzed yielded the following results: 12 operators affirmed to know the new eye lens dose limit, 53 operators routinely wore lead aprons, and 23 operators used lead glasses. Four workers performed eye lens dosimetry through specific dosimeters. A significant lack of knowledge of the reduced eye lens dose limit suggests the need to implement radioprotection-training programs aimed at raising awareness about the importance of health care in the workplace and at reducing the risk of radio-induced effects to the eye lens.

Evaluation of the current status of the eye lens radiation exposure in an Interventional Radiology department.

BACKGROUND: Following recent epidemiological studies, which showed tissue reactions from ionizing radiation at significantly lower doses, the 2013/59 EURATOM Directive of 5th December 2013 lowered the limit on the equivalent dose to the eye lens from 150 mSv to 20 mSv per year. Therefore, as a precautionary measure, it is considered appropriate to perform a timely dose monitoring by using specific dosimeters. OBJECTIVES: Analysis of the current state of the eye lens exposures during interventional procedures. The survey aimed at assessing the degree of information available to the exposed workers as regards lowering the dose limit in Interventional Radiology departments of some hospitals in Campania (Southern Italy). METHODS: The equivalent dose was assessed, over a period of 90 days, using specific Hp dosimeters(3), placed sideways with regard to prescription eye glasses. The level of awareness of the new dose limit among operators was assessed using a questionnaire. RESULTS: The values of the equivalent dose to the lens of the eye for the I and II Operators were found to be <150 mSv/year but for the I Operator a value of 54 mSv/year was obtained, ie higher than 20 mSv/year, that is the new limit of the equivalent dose according to 2013/59 EURATOM. The initial results of the questionnaire from 52 exposed workers, of which 46 (88%) were from exposure category A and 6 (12%) from category B, showed a low level of information (19%). CONCLUSIONS: The results highlight not only the importance of using specific devices for individual protection but also the importance of the level of training and information the exposed medical staff are given concerning the new regulations.

Survival and Adaptation of the Thermophilic Species Geobacillus thermantarcticus in Simulated Spatial Conditions.

Astrobiology studies the origin and evolution of life on Earth and in the universe. According to the panspermia theory, life on Earth could have emerged from bacterial species transported by meteorites, that were able to adapt and proliferate on our planet. Therefore, the study of extremophiles, i.e. bacterial species able to live in extreme terrestrial environments, can be relevant to Astrobiology studies. In this work we described the ability of the thermophilic species Geobacillus thermantarcticus to survive after exposition to simulated spatial conditions including temperature's variation, desiccation, X-rays and UVC irradiation. The response to the exposition to the space conditions was assessed at a molecular level by studying the changes in the morphology, the lipid and protein patterns, the nucleic acids. G. thermantarcticus survived to the exposition to all the stressing conditions examined, since it was able to restart cellular growth in comparable levels to control experiments carried out in the optimal growth conditions. Survival was elicited by changing proteins and lipids distribution, and by protecting the DNA's integrity.

Evaluation of Dose Homogeneity in Cone-Beam Breast Computed Tomography.

The aim of this study is to determine, via measurements on phantoms and Monte Carlo (MC) simulations, the dose distribution of absorbed dose in a cone-beam breast computed tomography scan. The absorbed dose volume distribution was measured inside a polyethylene cylindrical phantom, simulating adipose breast tissue, using LiF:Mg,Ti thermoluminescence dosimeters. A reasonable agreement (between 2 and 8%) between the simulated and measured data was observed. The 3D distribution of absorbed dose was evaluated at 40, 60 and 80 kV in a phantom simulating a pendant breast. MC simulations indicate a significantly lower spread of volume dose than in mammography. The dose variation along the radial distance in the simulated phantoms was in the range of 4‒14%. These findings might be useful when devising models for breast imaging dose assessment that take into account the uneven distribution of the glandular mass in the breast volume.

X-rays effects on cytoskeleton mechanics of healthy and tumor cells.

Alterations in the cytoskeleton structure are frequently found in several diseases and particularly in cancer cells. It is also through the alterations of the cytoskeleton structure that cancer cells acquire most of their common features such as uncontrolled cell proliferation, cell death evasion, and the gaining of migratory and invasive characteristics. Although radiation therapies currently represent one of the most effective treatments for patients, the effects of X-irradiation on the cytoskeleton architecture are still poorly understood. In this case we investigated the effects, over time of two different doses of X-ray irradiation, on cell cytoskeletons of BALB/c3T3 and Sv40-transformed BALB/c 3T3 cells (SVT2). Biophysical parameters - focal adhesion size, actin bundles organization, and cell mechanical properties - were measured before and after irradiations (1 and 2 Gy) at 24 and 72 h, comparing the cytoskeleton properties of normal and transformed cells. The differences, before and after X-irradiation, were revealed in terms of cell morphology and deformability. Finally, such parameters were correlated to the alterations of cytoskeleton dynamics by evaluating cell adhesion at the level of focal adhesion and cytoskeleton mechanics. X-irradiation modifies the structure and the activity of cell cytoskeleton in a dose-dependent manner. For transformed cells, radiation sensitively increased cell adhesion, as indicated by paxillin-rich focal adhesion, flat morphology, a well-organized actin cytoskeleton, and intracellular mechanics. On the other hand, for normal fibroblasts IR had negligible effects on cytoskeletal and adhesive protein organization. © 2016 Wiley Periodicals, Inc.

Indoor radon activity concentration measurements in the great historical museums of University of Naples, Italy.

Indoor radon activity concentrations were measured in seven Museums of University of Naples, very old buildings of great historical value. The measurements were performed using a time-integrated technique based on LR-115 solid-state nuclear track detectors. The annual average concentrations were found to range from 40 up to 1935 Bq m(-3) and in 26 % of measurement sites, the values were higher than 500 Bq m(-3) which is the limit value of Italian legislation for workplace. Moreover, we analysed the seasonal variations of radon concentrations observing the highest average in cold weather than in warm.