76 research outputs found

    Alien Registration- Vikstrom, Einor Borje (Bangor, Penobscot County)

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    https://digitalmaine.com/alien_docs/13957/thumbnail.jp

    Radioactive Contamination Of Natural Biological Systems: Oxidative Balance And Genetic Stability

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    The global demand for nuclear energy grows, and so do the risks of an accidental release of nuclear products into the environment. Therefore, understanding the health and ecological effects of contamination by radionuclides should be of great interest for biomedical specialists and the public. Empirical studies unequivocally show that high doses of ionizing radiation (IR) shift the redox-balance of many biological systems and increase the rates of genetic errors. However, the effects of chronic low doses of radiation vary significantly between tissues and between species. The present dissertation comprises the results of experimental and meta-analytical research of a variety of biological effects of environmental contamination by radioactive isotopes. In the review part (Chapter 1), I performed a rigorous literature analysis of the environmental consequences of the three most serious nuclear accidents – the Fukushima Daiichi nuclear power plant (NPP) accident in Japan (2011); meltdown at the Chernobyl NPP in 1986; and the explosion at the Mayak plutonium production site (both former USSR) in 1957. The results of the meta-analysis demonstrate significant effects of the low ( In the experimental part of this thesis (Chapter 2&3), I presented the results of several tests, by which I aimed to detect the detrimental genetic effects of low dose IR. I tested for the presence of radiation-induced damage in DNA and related that to radionuclide body burdens and fitness of a model animal. The bank vole was used as a vertebrate model and the wild downy dragonfly as an invertebrate model. Both species were sampled in the Chernobyl Exclusion Zone (CEZ), as it remains significantly contaminated by the biologically effective isotopes: cesium-137 and strontium-90. In the results, I demonstrate that natural variation in comet-visualized DNA damage exceeds the additive effect of damage from ionizing radiation. It was also shown that accounting for morphological co-variates, such as sex and age, and random co-variates, such as sampling period, is important in prediction of genetic damage using the comet assay

    Unsupervised learning for detection of possible sexual dimorphism in larvae of Belgica antarctica Jacobs (Diptera, Chironomidae)

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    Belgica antarctica is one of the two native chironomid species of the Antarctic Peninsula. In this species, adult males and females are considerably different, yet the question of larval sex differences in morphometric parameters remains unanswered. In this paper, we analyze five morphometric parameters: head capsule length, head capsule width, mandible width, mandible length, mentum length of 140 fourth-instar larvae of B. antarctica from seven study plots in the south of Petermann Island, Wilhelm Archipelago, Antarctic Peninsula. To infer possible sexual dimorphism, we use the methods of unsupervised analysis (PCA and hierarchical clusterization). Our results suggest that the selected morphometric features of width and length are highly intercorrelated and cannot differentiate sex in the sampled larvae of B. antarctica

    Association between intracranial vessel calcifications, structural brain damage, and cognitive impairment after minor strokes: a prospective study

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    BackgroundVascular calcifications are a hallmark of atherosclerosis, and in the coronary arteries are routinely used as a prognostic marker. Calcifications of intracranial vessels (ICC) are frequently observed on non-contrast CT (NCCT) and their effect on post-stroke cognitive impairment (PSCI) remains unclear. Our aim was to explore the association of ICC with prospective long-term cognitive function and advanced MRI-measures in a large prospective cohort of cognitively intact mild stroke survivors.MethodsData from the Tel-Aviv brain acute stroke cohort (TABASCO) study [ClinicalTrials.gov #NCT01926691] were analyzed. This prospective cohort study (n = 575) aimed to identify predictors of PSCI, in cognitively intact mild stroke survivors. A quantitative assessment of the intracranial calcium content – The ICC score (ICCS) was calculated semi-automatically on NCCT using a validated calcium quantification application. Participants underwent a 3 T-MRI and prospective comprehensive cognitive clinical and laboratory assessments at enrollment, 6, 12, and 24-months.ResultsData were available for 531 participants (67.4 years, 59.5% males). The incidence of PSCI at two-years doubled in the high ICCS group (26% vs. 13.7%, p < 0.001). The high ICCS group had significantly greater small-vessel-disease (SVD) tissue changes and reduced microstructural-integrity assessed by Diffusion-Tensor-Imaging (DTI) maps (p < 0.05 for all). In multivariate analysis, a higher ICCS was independently associated with brain atrophy manifested by lower normalized white and gray matter, hippocampal and thalamic volumes (β = −0.178, β = −0.2, β = −0.137, β = −0.157; p < 0.05) and independently predicted PSCI (OR 1.83, 95%CI 1.01–3.35).ConclusionOur findings suggest that the ICCS, which is a simple and readily available imaging marker on NCCT, is associated with brain atrophy, microstructural damage, the extent of SVD, and may predict PSCI. This finding has implications for identifying individuals at risk for PSCI and implementing targeted interventions to mitigate this risk

    Assess the annual effective dose and contribute to risk of lung cancer caused by internal radon 222 in 22 regions of Tehran, Iran using geographic information system

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    Radon gas is one of the most influential sources of indoor exposure. All its physical properties together make it a significant risk factor for lung cancer in the population. The research aims are outlined as (1) to measure the radon concentration in Tehran city and compare results with the international standards (2) to determine spatial distribution of radon gas concentration using Geographical Information System (GIS) software and (3) to estimate the annual effective dose and potential risk of lung cancer by radon-222 in Tehran city. In this study, 800 Alpha Track detectors were installed in houses in 22 regions of Tehran city and retrieved after 3 months. The measurements were repeated for spring and summer and autumn seasons. The annual effective dose and risk of lung cancer were assessed using standard equations. Data were analyzed using SPSS 20. Result showed the minimum and maximum radon concentration were observed in and Ghalee-kobra (0.13 Bq.m-3) and Charbagh-ponak district (661.11 Bq.m-3) respectively. There was no observed relationship between radon concentration and houses' model, cracking condition and constructionn materials. Expectedly, the storehouses and basements had significantly higher (P = 0.016) radon concentration than occupied rooms. The min and max of the estimated annual effective dose were 0.65 and 2.03 mSv, respectively. Result showed that around 5 of the sampling sites had higher level of radon than the maximum allowed by EPA. A rough estimation of the expected radon-attributed lung cancer incidences yielded approximately 5958 cases in the total population of Tehran every year. In view of the growing trend in cancer incidences, appropriate measures addressing radon should be undertaken in areas of increased exposure to this noble gas. © 2020 Springer Nature Switzerland AG

    Research Liaisons: the next layer of Facilitation

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    This item includes a conference paper and the accompanying presentation given at the conference. The presentation was prerecorded.Research productivity has been greatly enhanced by Research Computing Facilitation teams to help researchers maximize their use of advanced cyberinfrastructure. However, researchers have more technology needs than just advanced cyberinfrastructure, such as data management and instrument device support. To address this, the Academic Engagement team in Michigan Medicine added Research Liaisons as another layer of human support on top of the Facilitation team. The Liaisons are relationship builders. They are assigned to departments to build deep relationships with them and start proactively addressing labs’ technology needs. They also build relationships with other teams, notably enterprise storage, enterprise networking, and research core facilities. These relationships allow Liaisons to provide a connective tissue between the researchers and IT teams.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/170574/1/McCaffrey et al. - 2021 - Research Liaisons the next layer of Facilitation.pdfDescription of McCaffrey et al. - 2021 - Research Liaisons the next layer of Facilitation.pdf : Main articleSEL

    Ionizing radiation, higher plants, and radioprotection: From acute high doses to chronic low doses

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    © 2018 Caplin and Willey. Understanding the effects of ionizing radiation (IR) on plants is important for environmental protection, for agriculture and horticulture, and for space science but plants have significant biological differences to the animals from which much relevant knowledge is derived. The effects of IR on plants are understood best at acute high doses because there have been; (a) controlled experiments in the field using point sources, (b) field studies in the immediate aftermath of nuclear accidents, and (c) controlled laboratory experiments. A compilation of studies of the effects of IR on plants reveals that although there are numerous field studies of the effects of chronic low doses on plants, there are few controlled experiments that used chronic low doses. Using the Bradford-Hill criteria widely used in epidemiological studies we suggest that a new phase of chronic low-level radiation research on plants is desirable if its effects are to be properly elucidated. We emphasize the plant biological contexts that should direct such research. We review previously reported effects from the molecular to community level and, using a plant stress biology context, discuss a variety of acute high-and chronic low-dose data against Derived Consideration Reference Levels (DCRLs) used for environmental protection. We suggest that chronic low-level IR can sometimes have effects at the molecular and cytogenetic level at DCRL dose rates (and perhaps below) but that there are unlikely to be environmentally significant effects at higher levels of biological organization. We conclude that, although current data meets only some of the Bradford-Hill criteria, current DCRLs for plants are very likely to be appropriate at biological scales relevant to environmental protection (and for which they were intended) but that research designed with an appropriate biological context and with more of the Bradford-Hill criteria in mind would strengthen this assertion. We note that the effects of IR have been investigated on only a small proportion of plant species and that research with a wider range of species might improve not only the understanding of the biological effects of radiation but also that of the response of plants to environmental stress

    Impact of Cerebral Microbleeds in Stroke Patients with Atrial Fibrillation

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    OBJECTIVES: Cerebral microbleeds are associated with the risks of ischemic stroke and intracranial hemorrhage, causing clinical dilemmas for antithrombotic treatment decisions. We aimed to evaluate the risks of intracranial hemorrhage and ischemic stroke associated with microbleeds in patients with atrial fibrillation treated with Vitamin K antagonists, direct oral anticoagulants, antiplatelets, and combination therapy (i.e. concurrent oral anticoagulant and antiplatelet) METHODS: We included patients with documented atrial fibrillation from the pooled individual patient data analysis by the Microbleeds International Collaborative Network. Risks of subsequent intracranial hemorrhage and ischemic stroke were compared between patients with and without microbleeds, stratified by antithrombotic use. RESULTS: A total of 7,839 patients were included. The presence of microbleeds was associated with an increased relative risk of intracranial hemorrhage (aHR 2.74, 95% confidence interval 1.76 - 4.26) and ischemic stroke (aHR 1.29, 95% confidence interval 1.04 - 1.59). For the entire cohort, the absolute incidence of ischemic stroke was higher than intracranial hemorrhage regardless of microbleeds burden. However, for the subgroup of patients taking combination of anticoagulant and antiplatelet therapy, the absolute risk of intracranial hemorrhage exceeded that of ischemic stroke in those with 2-4 microbleeds (25 vs 12 per 1,000 patient-years) and ≥11 microbleeds (94 vs 48 per 1,000 patient-years). INTERPRETATION: Patients with atrial fibrillation and high burden of microbleeds receiving combination therapy have a tendency of higher rate of intracranial hemorrhage than ischemic stroke, with potential for net harm. Further studies are needed to help optimize stroke preventive strategies in this high-risk group. This article is protected by copyright. All rights reserved

    Post-stroke dementia - a comprehensive review

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    Post-stroke dementia (PSD) or post-stroke cognitive impairment (PSCI) may affect up to one third of stroke survivors. Various definitions of PSCI and PSD have been described. We propose PSD as a label for any dementia following stroke in temporal relation. Various tools are available to screen and assess cognition, with few PSD-specific instruments. Choice will depend on purpose of assessment, with differing instruments needed for brief screening (e.g., Montreal Cognitive Assessment) or diagnostic formulation (e.g., NINDS VCI battery). A comprehensive evaluation should include assessment of pre-stroke cognition (e.g., using Informant Questionnaire for Cognitive Decline in the Elderly), mood (e.g., using Hospital Anxiety and Depression Scale), and functional consequences of cognitive impairments (e.g., using modified Rankin Scale). A large number of biomarkers for PSD, including indicators for genetic polymorphisms, biomarkers in the cerebrospinal fluid and in the serum, inflammatory mediators, and peripheral microRNA profiles have been proposed. Currently, no specific biomarkers have been proven to robustly discriminate vulnerable patients (‘at risk brains’) from those with better prognosis or to discriminate Alzheimer’s disease dementia from PSD. Further, neuroimaging is an important diagnostic tool in PSD. The role of computerized tomography is limited to demonstrating type and location of the underlying primary lesion and indicating atrophy and severe white matter changes. Magnetic resonance imaging is the key neuroimaging modality and has high sensitivity and specificity for detecting pathological changes, including small vessel disease. Advanced multi-modal imaging includes diffusion tensor imaging for fiber tracking, by which changes in networks can be detected. Quantitative imaging of cerebral blood flow and metabolism by positron emission tomography can differentiate between vascular dementia and degenerative dementia and show the interaction between vascular and metabolic changes. Additionally, inflammatory changes after ischemia in the brain can be detected, which may play a role together with amyloid deposition in the development of PSD. Prevention of PSD can be achieved by prevention of stroke. As treatment strategies to inhibit the development and mitigate the course of PSD, lowering of blood pressure, statins, neuroprotective drugs, and anti-inflammatory agents have all been studied without convincing evidence of efficacy. Lifestyle interventions, physical activity, and cognitive training have been recently tested, but large controlled trials are still missing
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