Long-term Effects Of Radiation Research Articles

Long-Term, Sex-Specific Effects of GCRsim and Gamma Irradiation on the Brains, Hearts, and Kidneys of Mice with Alzheimer's Disease Mutations.

Understanding the hazards of space radiation is imperative as astronauts begin voyaging on missions with increasing distances from Earth's protective shield. Previous studies investigating the acute or long-term effects of specific ions comprising space radiation have revealed threats to organs generally considered radioresistant, like the brain, and have shown males to be more vulnerable than their female counterparts. However, astronauts will be exposed to a combination of ions that may result in additive effects differing from those of any one particle species. To better understand this nuance, we irradiated 4-month-old male and female, wild-type and Alzheimer's-like mice with 0, 0.5, or 0.75 Gy galactic cosmic ray simulation (GCRsim) or 0, 0.75, or 2 Gy gamma radiation (wild-type only). At 11 months, mice underwent brain and heart MRIs or behavioral tests, after which they were euthanized to assess amyloid-beta pathology, heart and kidney gene expression and fibrosis, and plasma cytokines. Although there were no changes in amyloid-beta pathology, we observed many differences in brain MRIs and behavior, including opposite effects of GCRsim on motor coordination in male and female transgenic mice. Additionally, several genes demonstrated persistent changes in the heart and kidney. Overall, we found sex- and genotype-specific, long-term effects of GCRsim and gamma radiation on the brain, heart, and kidney.

DELAYED EFFECTS OF RADIATION: A LITERATURE REVIEW

Relevance: The effect of radiation on the immune system of the offspring of persons affected by exposure to low doses of various radiation types is still an urgent issue. In the literature, several issues related to delayed consequences, namely, morphofunctional disorders in the organs of the descendants of irradiated individuals, have not received adequate resolution. The purpose was to analyze literature on the long-term effects of radiation, manifested by morphofunctional disorders of the immunocompetent organs in the descendants of persons exposed to radiation, to confirm the importance of further study of this issue. Methods: The review included publications indexed in PubMed, Medline, E-library, and CyberLeninka databases. The search was made using the Google Scholar search engine. The applied search filters included conducted experimental studies over the past eight years (2015-2023). Results: The search revealed insufficient publications devoted to studying metabolic processes and histomorphological changes in the immunocompetent organs of the body of the descendants of exposed individuals. An insufficient number of publications on long-term biochemical and pathohistological changes in immune system organs due to irradiation necessitate a profound study of the topic. Conclusion: The study of morphofunctional disorders in the descendants of the first generation of irradiated individuals remains a task for radiobiologists and oncologists, with the development of criteria for morphological diagnosis.

Assessment of peripheral dose as a function of distance and depth from cobalt-60 beam in water phantom using TLD-100

BackgroundInnovations in cancer treatment have contributed to the improved survival rate of cancer patients. The cancer survival rates have been growing and nearly two third of those survivors have been exposed to clinical radiation during their treatment. The study of long-term radiation effects, especially secondary cancer induction, has become increasingly important. An accurate assessment of out-of-field/peripheral dose (PDs) is necessary to estimate the risk of second cancer after radiotherapy and the damage to the organs at risk surrounding the planning target volume. This study was designed to measure the PDs as a function of dose, distances, and depths from Telecobalt-60 (Co-60) beam in water phantom using thermoluminescent dosimeter-100 (TLD-100).MethodsThe PDs were measured for Co-60 beam at specified depths of 0 cm (surface), 5 cm, 10 cm, and 15 cm outside the radiation beam at distances of 5, 10, and 13 cm away from the radiation field edge using TLD-100 (G1 cards) as detectors. These calibrated cards were placed on the acrylic disc in circular tracks. The radiation dose of 2000 mGy of Co-60 beam was applied inside 10 × 10 cm2 field size at constant source to surface distance (SSD) of 80 cm.ResultsThe results showed maximum and minimum PDs at surface and 5 cm depth respectively at all distances from the radiation field edge. Dose distributions out of the field edge with respect to distance were isotropic. The decrease in PDs at 5 cm depth was due to dominant forward scattering of Co-60 gamma rays. The increase in PDs beyond 5 cm depth was due to increase in the irradiated volume, increase in penumbra, increase in source to axis distance (SAD), and increase in field size due to inverse square factor.ConclusionIt is concluded that the PDs depends upon depth and distance from the radiation field edge. All the measurements show PDs in the homogenous medium (water); therefore, it estimates absorbed dose to the organ at risk (OAR) adjacent to cancer tissues/planning target volume (PTV). It is suggested that PDs can be minimized by using the SAD technique, as this technique controls sources of scattered radiation like inverse square factor and effect of penumbra up-to some extent.

Radiation-Associated Vestibular Schwannomas: Case Series and Literature Review

Radiation treatment, particularly at a young age, creates theoretical risk for long-term adverse radiation effects, including the development of malignancy. The literature is sparse on radiation-induced vestibular schwannomas (VSs). A retrospective review was performed for cases of suspected radiation-induced VS at 2 high-volume centers. Only cases where radiation included coverage of the posterior fossa were included with those diagnosed within 3years of radiation treatment being excluded. Patient and tumor characteristics were collected. A systematic literature review was also performed for any previously published series on radiation-induced VS. Eight cases of radiation-induced VS were identified with a median follow-up 125months (range 7-131). The median age at incident radiation was 15years (range 2-46). The median age at VS diagnosis was 57 years (range 26-83) with median interval from radiation to diagnosis of 51-years (range 15-66). The median tumor size was 6mm (range 3-21). Two patients underwent surgical resection. Lesions were described as soft and highly vascular, with medium to high adherence to the facial nerve. Five articles with a total of 52 patients were identified, median age at VS diagnosis was 42-years (range 23-73) with a median interval from radiation to diagnosis of 19years (range 15-23). The development of VS following radiation exposure appears rare and our understanding of the condition remains incomplete. Further studies are required to determine the best management of these patients and determine whether there is a causative relationship between radiation exposure and the development of VS.

Cycles of solar ultraviolet radiation favor periodic expansions of cyanobacterial blooms in global lakes

Global warming and eutrophication are known to increase the prevalence of cyanobacterial blooms, posing a severe threat to the ecological stability and sustainability of water bodies. The long-term (over an annual time frame) effect of UV radiation on cyanobacterial blooms in lakes are rarely discussed though the substantial effects of high-intensity UV radiation on the growth inhibition of marine phytoplankton were studied. Here, we employed the datasets on surface solar UV radiation, nitrogen and phosphorus concentrations, and the annual scales and frequencies of cyanobacterial blooms in lakes across long-term spatial scales to probe the relationship of UV radiation with cyanobacterial blooms. The results indicated that enhanced solar UV radiation may unintentionally stimulate cyanobacterial growth and favor the expansions of cyanobacterial blooms in lakes around the world. The fluctuating UV radiation significantly affects the annual scales of cyanobacterial blooms in both eutrophic and oligotrophic lakes. Solar UV radiation enhances the positive impact of rising phosphorus levels on cyanobacterial blooms because UV radiation prompts the synthesis of polyphosphate in cyanobacteria cells, which helps cyanobacteria to alleviate the stress of UV light. The scales of cyanobacterial blooms are significantly impacted by solar UV radiation intensities as opposed to the annual frequency of cyanobacterial blooms. Furthermore, solar UV radiation fluctuation with a 9-year period over a 14-year main cycles significantly affects the periodicities of cyanobacterial blooms in global lakes, which provides a basis for predicting the peak value of the scales of cyanobacterial blooms in lakes. These findings opened up new avenues of inquiry into the mechanism and management strategies of cyanobacterial blooms in lakes worldwide.

Роль клеточного иммунитета в развитии злокачественных новообразований у лиц, подвергшихся хроническому облучению

Some long-term effects of radiation could be related to changes in the immune system resulting from radiation exposure. Immunity disorders caused by radiation can influence carcinogenesis. Cellular immunity factors were investigated in peripheral blood of workers chronically exposed to occupational combined radiation (external gamma-rays and internal alpha-particles), with malignant neoplasms diagnosed after blood samples were taken or without them, and in the control group. The aim of this study was examine effects of radiation on the cellular immunity status in individuals chronically exposed to ionizing radiation who had malignant neoplasms developed after blood sampling. The relative and absolute number of lymphocyte subpopulations (total T-cells, T-helpers, T-cytotoxic, total B-cells, NK-cells, NKT-cells and activated T-cells) was detected by flow cytofluorometry. The absolute number of T-cells was significantly reduced in workers chronically exposed to occupational combined irradiation, with or without malignancies, compared to the control, which may contribute to tumor progression at an early stage of its onset. At the same time, workers without malignancies had a significant increase in the relative number of T-cytotoxic lymphocytes, which may be a factor preventing tumor development. A significant increase in the relative number of natural killer cells (NK cells) was detected in individuals with malignant neoplasms chronically exposed to occupational combined irradiation, compared with the control, which may indicate enhanced antitumor defense that developed in response to exposure to tumor antigens. In addition, a significant decrease in the absolute and relative number of T- and B-lymphocytes was found in the group of workers with malignant neoplasm, compared with the control. A significant increase in the relative number of T-helpers was found in both groups of workers. Since the role of T-helpers in the antitumor response is ambiguous, additional research on types of T-helpers is planned to clarify the results of the present study

Role of cellular immunity in malignant tumors development in individuals chronically ex-posed to ionising radiation

Some long-term effects of radiation could be related to changes in the immune system resulting from radiation exposure. Immunity disorders caused by radiation can influence carcinogenesis. Cellular immunity factors were investigated in peripheral blood of workers chronically exposed to occupational combined radiation (external gamma-rays and internal alpha-particles), with malignant neoplasms diagnosed after blood samples were taken or without them, and in the control group. The aim of this study was examine effects of radiation on the cellular immunity status in individuals chronically exposed to ionizing radiation who had malignant neoplasms developed after blood sampling. The relative and absolute number of lymphocyte subpopulations (total T-cells, T-helpers, T-cytotoxic, total B-cells, NK-cells, NKT-cells and activated T-cells) was detected by flow cytofluorometry. The absolute number of T-cells was significantly reduced in workers chronically exposed to occupational combined irradiation, with or without malignancies, compared to the control, which may contribute to tumor progression at an early stage of its onset. At the same time, workers without malignancies had a significant increase in the relative number of T-cytotoxic lymphocytes, which may be a factor preventing tumor development. A significant increase in the relative number of natural killer cells (NK cells) was detected in individuals with malignant neoplasms chronically exposed to occupational combined irradiation, compared with the control, which may indicate enhanced antitumor defense that developed in response to exposure to tumor antigens. In addition, a significant decrease in the absolute and relative number of T- and B-lymphocytes was found in the group of workers with malignant neoplasm, compared with the control. A significant increase in the relative number of T-helpers was found in both groups of workers. Since the role of T-helpers in the antitumor response is ambiguous, additional research on types of T-helpers is planned to clarify the results of the present study.

Effects on Lung Tissue After Breast Cancer Radiation: Comparing Photon and Proton Therapies

PurposeIn breast cancer, improved treatment approaches that reduce injury to lung tissue and early diagnosis and intervention for lung toxicity are increasingly important in survivorship. The aims of this study are to (1) compare lung tissue radiographic changes in women treated with conventional photon radiation therapy and those treated with proton therapy (PT), (2) assess the volume of lung irradiated to 5 Gy (V5) and 20 Gy (V20) by treatment modality, and (3) quantify the effects of V5, V20, time, and smoking history on the severity of tissue radiographic changes. Patients and MethodsA prospective observational study of female breast cancer patients was conducted to monitor postradiation subclinical lung tissue radiographic changes. Repeated follow-up x-ray computed tomography scans were acquired through 2 years after treatment. In-house software was used to quantify an internally normalized measure of pulmonary tissue density change over time from the computed tomography scans, emphasizing the 6- and 12-month time points. ResultsCompared with photon therapy, PT was associated with significantly lower lung V5 and V20. Lung V20 (but not V5) correlated significantly with increased subclinical lung tissue radiographic changes 6 months after treatment, and neither correlated with lung effects at 12 months. Significant lung tissue density changes were present in photon therapy patients at 6 and 12 months but not in PT patients. Significant lung tissue density change persisted at 12 months in ever-smokers but not in never-smokers. ConclusionPatients treated with PT had significantly lower radiation exposure to the lungs and less statistically significant tissue density change, suggesting decreased injury and/or improved recovery compared to photon therapy. These findings motivate additional studies in larger, randomized, and more diverse cohorts to further investigate the contributions of treatment modality and smoking regarding the short- and long-term radiographic effects of radiation on lung tissue.

Current and Future Treatments, Prevention, Diagnosis on Retinoblastoma

The most frequent intraocular cancer in children is retinoblastoma. All pediatric patients with retinoblastoma must undergo genetic testing as a crucial part of their treatment. Retinoblastoma can also extend to the brain and spine, among other parts of the body. MRI and CT scans are two imaging procedures that may be used to detect retinoblastoma. The size and location of the retinoblastoma tumor in your child determine the optimal course of treatment. Chemotherapy is a type of medication that can be used to treat cancer. Chemotherapy can aid in tumor reduction, enabling subsequent therapies like radiation therapy, cryotherapy, or laser therapy to target any remaining cancer cells. Early eye examinations are crucial for diagnosis and care. If detected early, retinal blastoma is frequently treatable. A hereditary mutation may cause retinal tumors (retinoblastoma). External beam radiation therapy, cryotherapy, laser photocoagulation, thermotherapy, brachytherapy, and chemotherapy (intravitreal, intra-arterial, and systemic) are now included in the treatment of retinoblastoma in addition to the damaged globe. Long-term side effects of radiation and chemotherapy in retinoblastoma patients can include secondary cancers.

Demystifying the Role of Radiation Dose Bath in Brain Injury Using Machine Learning.

It is well known that high-dose radiation results in brain injury, the long-term effects of low-dose radiation, however, is uncertain. The purpose of this study was to investigate the role of low-dose bath on MRI changes, on both clinical and micro-architectural levels, using machine learning and computational methods. Six hundreds and fifty-six temporal lobe and 45 whole brain DVHs from patients treated for nasopharyngeal cancer (NPC) with IMRT or proton were included in this study. Temporal lobe injury (TLI) was defined as development of new T1 enhancement on MRI with or without surrounding T2 edema. Patients were divided randomly into train (50%) and test (50%) sets. Accuracy and AUC were used to evaluate the model performance. Minimum redundancy maximum relevance (MRMR) or SHAP algorithms was employed for feature selection. Support vector machine or random forest was used for classification. Automated cortical region segmentation using FreeSurfer v6 was performed in 33 patients with a minimum follow-up of 4 years. Architectural and biological MRI changes were determined in 34 different brain regions for each individual patient. The top-ranked temporal lobe features predicting TLI were V66/V38 for IMRT patients and V10 for proton patients with an AUC of 0.95 and 0.74, respectively. For whole brain, the top features were V16 and V13 with an AUC of 0.70. The rates of TLI at 5 years for V10-20(whole brain) ≥ 180cc and V10-20(whole brain) < 180 were 39.5% and 6.2%, respectively (HR = 5.5, 95% CI 1.4-22.0, p = 0.02). There were global changes in gray matter thickness, with most pronounced changes occurred in parietal lobe (-4.79%, p = 0.007) and occipital lobe (-5.68%, p = 0.03). Similarly, there were diffuse changes in white matter and subcortical volume. After radiation, the frontal lobe increased by 17.5% (p = 0.04), lateral ventricle 41% (p = 0.03), and choroid plexus 34.3% (p = 0.03). Low-dose radiation bath is associated with increased risk of temporal lobe injury and global disruption in brain architecture in NPC survivors.

Uncommon short- and long-term cardiological side effects of thoracic radiation: a report of two cases.

Radiotherapy is an essential treatment of more than 50% of oncohematological patients. Pericardial disorders and valvular heart disease are two common radiotherapy complications. Acute pericarditis is infrequent and usually underdiagnosed. Therefore, diagnostic suspicion and early treatment are mandatory to avoid the evolution to constrictive pericarditis. The prevalence of radiation-induced valvular heart disease is common in patients with a history of Hodgkin's lymphoma and breast cancer. It has distinctive characteristics from other etiologies and, thus, different therapeutic approaches. We present two cases of unusual complications of radiotherapy; the first one in the acute setting and the second one during the follow-up in the chronic phase. A multidisciplinary and individualized approach with specific considerations is decisive in the management of these patients.

A Cadaveric Simulation Study of Radiation Exposure to the Surgical Team during Fluoroscopic Spinal Surgery: How Much Are We Exposed?

The harmful effects of long-term low-dose radiation have been well known. There are few comprehensive reports evaluating concrete real exposure doses for each part of a surgeon, assistant surgeon, scrub nurse, and anesthesiologist associated with fluoroscopic spinal procedures. This research aimed to quantify the radiation exposure dose to surgical team members during C-arm fluoroscopy-guided spinal surgery. Seven fresh cadavers were irradiated for 1 and 3 min with C-arm fluoroscopy. The position of the X-ray source was under the table, over the table, and laterally. The radiation exposure doses were measured at the optic lens, thyroid gland, and hand in mannequins used to simulate surgical team members. A significant difference was observed in the radiation exposure dose according to the position of the X-ray source and the irradiated body area. The risk of scatter radiation exposure was the biggest for the lateral position (nearly 30-fold that for the position under the table). All radiation exposure doses were positively correlated with irradiation time. The occupational radiation exposure dose to surgical team members during C-arm fluoroscopy-guided lumbar spinal procedures varies according to the X-ray source position. Our findings would help surgical team members to know the risk of radiation exposure during various fluoroscopic procedures. Surgeons in particular need to reduce their radiation exposure by using appropriate shielding and technique.

The Effects of Whole Body Gamma Irradiation on Mice, Age-Related Behavioral, and Pathophysiological Changes.

We designed a study with the objective to determine the long-term radiation effects of gamma rays, originating from a single shot of Co60 at a dose of 2Gy on the 7-month-old male mice of the ICR line in 30days after the irradiation. The aim of this study was to characterize the behavior of animals using the Open Field test, immuno-hematological status, and morpho-functional changes in the central nervous system of mice. Irradiated animals displayed significantly different behavior in the OF in comparison with the control group. The radiation damage was confirmed by assessing the ratio of leukocytes in the peripheral blood of mice at a later date after exposure to Co60. After irradiation, a decrease in the glioneuronal complex was observed in the irritated group as well as histological changes of brain cells. To sum up, not only was the hematological status of mice altered upon the total gamma irradiation, but also their behavior, which was most probably due to significant alterations in the CNS. Study of influence of ionizing radiation on female mice, comparison between different age groups. Open Field test on the 30days after 2Gy of γ-rays and histological analysis indicated changes in behavioral patterns, leucocytes, and brain tissue.

Recognition and Management of the Long-term Effects of Cranial Radiation.

Cranial radiation is ubiquitous in the treatment of primary malignant and benign brain tumors as well as brain metastases. Improvement in radiotherapy targeting and delivery has led to prolongation of survival outcomes. As long-term survivorship improves, we also focus on prevention of permanent side effects of radiation and mitigating the impact when they do occur. Such chronic treatment-related morbidity is a major concern with significant negative impact on patient's and caregiver's respective quality of life. The actual mechanisms responsible for radiation-induced brain injury remain incompletely understood. Multiple interventions have been introduced to potentially prevent, minimize, or reverse the cognitive deterioration. Hippocampal-sparing intensity modulated radiotherapy and memantine represent effective interventions to avoid damage to regions of adult neurogenesis. Radiation necrosis frequently develops in the high radiation dose region encompassing the tumor and surrounding normal tissue. The radiographic findings in addition to the clinical course of the patients' symptoms are taken into consideration to differentiate between tissue necrosis and tumor recurrence. Radiation-induced neuroendocrine dysfunction becomes more pronounced when the hypothalamo-pituitary (HP) axis is included in the radiation treatment field. Baseline and post-treatment evaluation of hormonal profile is warranted. Radiation-induced injury of the cataract and optic system can develop when these structures receive an amount of radiation that exceeds their tolerance. Special attention should always be paid to avoid irradiation of these sensitive structures, if possible, or minimize their dose to the lowest limit.

Performance evaluation of pulse shape discrimination capable organic scintillators for space applications

Scintillators with pulse-shape discrimination (PSD) capability are of great interest to many fields in the scientific community. The ability to discern a gamma ray from a neutron using PSD varies between different types of scintillator materials and dopants. A new generation of organic scintillator materials with PSD capability were studied to determine their radiation hardness to neutron and gamma-ray radiation. The PSD capability, average pulse shapes, and light output of four types of organic scintillator were characterized before and after neutron and gamma-ray irradiation. The main goal of this investigation is to study the effects of long-term irradiation that may be experienced in space applications on the light output and particle discriminating capabilities of each material. EJ-270, EJ-276, organic glass, and Stilbene were tested. Damage due to neutron irradiation (displacement damage) was not observed in any of the scintillators up to 2.56×1011 n/cm2, except for Stilbene which showed a small (12%) decrease in light output. All scintillators presented some light output reduction after gamma-ray irradiation (total ionizing dose), with reductions of 17% (EJ-276 and OGS), 32% (EJ-270), and 42% (Stilbene) observed immediately after 100 kRad.

The effect of aboveground long-term low-dose ionizing radiation on soil microbial diversity and structure

Studies investigating the diversity and structure of soil microbial systems in response to ionizing radiation are scarce. In particular, effects of long-term low-dose radiation is rarely studied because of its unique conditions. In this study, an area in Chengdu, China, which has been irradiated by the radionuclide thorium-232 for more than 10 years was investigated. Four groups of samples with absorbed dose rates ranging from 192.906 ± 5.05 to 910.964 ± 41.09 nGy/h were collected to analyze the compositional and functional changes of the soil microbial systems in the region. The diversity and structure of the soil microbial systems were determined using high-throughput sequencing. Our results showed that long-term low-dose ionizing radiation had no significant effect on soil bacterial diversity, but had a great impact on fungal diversity. Long-term ionizing radiation strongly affected soil microbial community structure. Long-term low-dose ionizing radiation was shown to have a promoting effect on iron-oxidizing bacteria and ectomycorrhizal fungi and have an inhibiting effect on predatory or parasitic fungi, further affecting the soil C/N ratio. This study is of great reference significance for future research on the impact of long-term low-dose ionizing radiation on soil ecosystems.

Extremely Low Frequency-Electromagnetic Fields (ELF-EMF) Can Decrease Spermatocyte Count and Motility and Change Testicular Tissue.

Substantial evidence indicates that exposure to extremely low frequency-electromagnetic fields (ELF-EMFs) affects male reproductive system. The goal of this study was to evaluate the effects of long-term irradiation with ELF-EMF on sperm quality and quantity and testicular structure. In this case-control study, sixty male Sprague-Dawley rats were randomly divided into six groups. Experimental groups were exposed to ELF-EMF (50 Hz EMF, 100 µT) for either 1 h/day for 52 days (Group 1), 4 h/day for 52 days (Group 3), 1 h/day for 5 days (Group 5), 4 h/day for 52 days (Group 7). Groups 2, 4, 6 and 8 were only sham exposed at durations equal to Groups 1, 3, 5 and 7, respectively. Both count and motility of sperms were significantly decreased in animals exposed to ELF-EMF (1 h/day for 52 days, 4 h/day for 52 day, and 4 h/day for 5 days) compared to the sham-exposed groups (P<0.05). Serum testosterone levels showed a significant decrease in the animals exposed to ELF-EMF (4 h/day for 5 days) compared to the control groups (P<0.05). A significant decrease was observed in the volume of the seminiferous tubules, seminiferous tubules epithelium and interstitial tissue in the animals exposed to ELF-EMF for 4 h/day for 5 days. Tubules length was also reduced by 18% in animals exposed to ELF-EMF (4 h/day for 5 days). Our results show that ELF-EMF can reduce spermatocyte count and motility and is able to induce structural changes in testicular tissue.

Abstract No. 540 Correlations of Ionizing Radiation to Histopathologic Changes and Long-Term Biological Effects of Radiation

Abstract No. 540 Correlations of Ionizing Radiation to Histopathologic Changes and Long-Term Biological Effects of Radiation

Morphology and Performance of PolyVinyl Chloride Thin Films Doped with Polyorganosilanes against Photodegradation

The importance of polymeric additives has taken an important role in industrial technology and its development and the increase in the consumption period of industrial products, especially plastic products. Therefore, a different type of polymeric additive was used, which can be classified as another type of polymeric additive, where three types of polymers were synthesized as polymeric additives. These polymers differ from each other only in stereo geometry. Three geometric shapes of the polymer were synthesized, namely, ortho, meta, and para polymers. They were studied as photo stabilizers for PVC and compared as the best photostabilizer for PVC. Polyorganosiloxane was invented by various technologies. Polyorganosilanes and poly(vinyl chloride) (PVC) were combined to create homogeneous films. Various methods were used to investigate the effects of long-term irradiation on polyorganosilane-containing films. The development of side products containing polyene and carbonyl groups was observed in the infrared spectra of PVC films before, during, and after irradiation. The absorption bands' intensities of the functional groups associated with the polyorganosilanes were lower when it was present. Furthermore, it was observed that the weight of PVC films dropped less when irradiating them after hybridization with polyorganosilanes. In the presence of polyorganosilanes, there was also a minor alteration in the surface of irradiated PVC. Photodegradation of PVC is inhibited by polyorganosilanes. Hence, the role of polyorganosilanes to stabilize PVC against UV exposure has been studied.

Radiation-aware analog circuit design via fully-automated simulation environment

As a result of increased interest in space applications, radiation-aware circuit design has become a major concern to guarantee the safe operation of electronic systems operating under extreme space conditions. As the first step, several ad-hoc simulation approaches have been developed in analog and digital domains to estimate the functional behavior of circuits exposed to high radiation. However, most of these tools are application specific and stand-alone (not integrated into the simulation tools). Also, several commercial CAD solutions exist; however, access to these tools is limited due to security measures. To this end, we have developed a well-equipped, SPICE-integrated, and free-to-access simulation tool, RadiSPICE, capable of running statistical radiation simulations and performing extended temperature and sensitivity analyses. By using RadiSPICE, one can readily predict the functional behavior of circuits after long-term or short-term radiation effects. Moreover, the sensitivity analysis reveals vulnerabilities of the design against radiation and provides valuable design hints to the designer to make circuits radiation-hardened. To demonstrate the proposed tool, we have performed several experiments on two analog building blocks with different topologies (bandgap reference and comparator circuits) using RadiSPICE and discussed the robustness of the designs in detail.