Dynamics of oligodendrocyte generation and myelination in the human brain.

The myelination of axons by oligodendrocytes has been suggested to be modulated by experience, which could mediate neural plasticity by optimizing the performance of the circuitry. We have assessed the dynamics of oligodendrocyte generation and myelination in the human brain. The number of oligodendrocytes in the corpus callosum is established in childhood and remains stable after that. Analysis of the integration of nuclear bomb test-derived (14)C revealed that myelin is exchanged at a high rate, whereas the oligodendrocyte population in white matter is remarkably stable in humans, with an annual exchange of 1/300 oligodendrocytes. We conclude that oligodendrocyte turnover contributes minimally to myelin modulation in human white matter and that this instead may be carried out by mature oligodendrocytes, which may facilitate rapid neural plasticity.

Nuclear Imaginaries and Power in Oppenheimer.

Christopher Nolan's Oppenheimer is in awe of physics and the power it can bestow. Its central character is both mythic and human, and the film critiques and constructs the mythology surrounding him. The film presents science and technology as the individualized work of masculine genius, though it is ultimately more interested in nuclear weapons as political objects than as technological ones. Its nuclear imaginaries contain personal anxieties and stunning spectacle but also forget the nuclear uncanny and the human scale of nuclear weapons.

Virtuous violence from the war room to death row.

How likely is it that someone would approve of using a nuclear weapon to kill millions of enemy civilians in the hope of ending a ground war that threatens thousands of American troops? Ask them how they feel about prosecuting immigrants, banning abortion, supporting the death penalty, and protecting gun rights and you will know. This is the finding from two national surveys of Democrats and Republicans that measured support for punitive regulations and policies across these four seemingly unrelated issues, and a fifth, using nuclear weapons against enemy civilians (in survey 1) or approving of disproportionate killing with conventional weapons (in survey 2). Those who support these various policies that threaten harm to many people tend to believe that the victims are blameworthy and it is ethical to take actions or policies that might harm them. This lends support to the provocative notion of "virtuous violence" put forth by Fiske and Rai [A. P. Fiske, T. S. Rai, Virtuous Violence: Hurting and Killing to Create, Sustain, End, and Honor Social Relationships (2014)], who assert that people commit violence because they believe it is the morally right thing to do. The common thread of punitiveness underlying and connecting these issues needs to be recognized, understood, and confronted by any society that professes to value fundamental human rights and wishes to prevent important decisions from being affected by irrelevant and harmful sociocultural and political biases.

Atomville: Architects, Planners, and How to Survive the Bomb.

In the post-Hiroshima era, atomic cities-designed to survive a nuclear attack-remain in the science fiction realm. Yet Hungarian émigré Paul Laszlo, a successful architect in Southern California suburbia, had a utopian vision for a futuristic, paradoxically luxurious atomic city he called "Atomville," never built but nonetheless seriously proposed. Laszlo was one of the very few architects known to venture into atomic survival on this scale. This article focuses on why the architectural profession for the most part ignored the issues raised by the atomic bomb, and on Laszlo's role as an outlier. It also deals with the genesis of Atomville and its place among the many unrealized ideas put forward in the 1940s and 1950s for urban survival, including underground buildings, urban dispersal, linear cities, and cluster cities.

Women, Reactors, and Nuclear Weapons: From Revolutionary Liberation to the "Miss Atom" Pageant in (Post-)Soviet Russia.

This article considers the Soviet Union's successful efforts to employ more women specialists in nuclear science and technology, from the Bolshevik revolution in 1917 and the Soviet atomic bomb project to the Cold War and the present. Despite their contributions to building a Cold War military machine, women rarely reached the pinnacle of the scientific enterprise due to persistent views about their lesser capabilities as specialists. After the collapse of the Soviet Union, in a vastly changed social, political, and cultural climate, the claimed socialist equality of women gave way to more traditional views of their status in Russian society. For the nuclear enterprise, this change emerged in activities that had disappeared under communism such as the annual "Miss Atom" beauty pageant, a striking departure from Soviet attempts to involve women equally in science and technology.

War in Europe: health implications of environmental nuclear disaster amidst war.

Recent incidents at nuclear facilities in Ukraine related to the attacks from Russian forces highlight the fragility of nuclear power plants and other nuclear facilities in war and the very real potential for another environmental nuclear disaster and associated health risks in Europe. Nuclear catastrophes from war can occur from radioactive materials released from war threatened nuclear power plants and other nuclear facilities in war zones, in addition to the direct threat from the deployment of nuclear weaponry and can result in immediate and long-term health impacts. Despite historical nuclear catastrophic events, including the Chernobyl nuclear power plant accident and atomic bombings of Hiroshima and Nagasaki, and that for more than a century epidemiologists have studied the consequences of radiation exposures, there are still major unanswered questions regarding radiation risks and human health. Epidemiologists will need to continue to quantify the health effects from exposure to environmental radiation, including background radiation, and are able to contribute to conversations about reliance on nuclear energy and alternative energy futures. As a society we are compelled to rethink our ties to nuclear energy, especially with the potential of increasing reliance on nuclear power amid oil and gas crisis and considering climate change, nuclear warfare, including nuclear weapon testing, and the fragility of humanity and health to even low doses of radiation from these and other natural and unnatural sources.

Mortality and cancer incidence 1952-2017 in United Kingdom participants in the United Kingdom's atmospheric nuclear weapon tests and experimental programmes.

This study examines the mortality and cancer incidence experience among men who took part in the United Kingdom's atmospheric nuclear weapon tests between 1952-67. A cohort of 21 357 servicemen and male civilians from the UK who participated in the tests and a group of 22 312 controls were followed between 1952 and 2017. Analyses of mortality and cancer incidence were conducted. The overall mortality rate in the test participants was slightly higher relative risk (RR = 1.02, 90% CI 1.00-1.05,p= 0.04) than that in the control group. This difference was driven by similar increased risks for both all cancers combined (RR 1.03, 90% CI 1.00-1.07) and all non-cancer diseases (RR = 1.02, 90% CI 1.00-1.05). Leukaemia excluding chronic lymphatic incidence showed evidence of being raised relative to controls (RR = 1.38, 90% CI 1.10-1.75,p= 0.01). Leukaemia risks were driven by increased risks for chronic myeloid leukaemia (CML) (RR = 2.43, 90% CI 1.43-4.13,p= 0.003). Among non-cancer outcomes only cerebrovascular diseases showed increases in participants relative to controls. UK nuclear weapon tests participants have lower mortality rates compared to the national population although rates are slightly (2%) higher than in the study control group. Variation in background characteristics, that could not be accounted for in the analysis (e.g. smoking habits, diet), are a possible explanation for this difference. For leukaemia evidence of increased risk in the early years after the test has generally continued to diminish with time although for CML risks have persisted. There was some evidence that participants had higher mortality rates from cerebrovascular diseases than those in the control group. Assuming recorded radiation exposures (generally very low) are a true reflection of actual exposures then it is unlikely that any observed health effect will have been caused by radiation exposure.

The nature and consequences of a nuclear war: lessons for prevention from Ukraine 2022.

This article attempts to put the Ukrainian conflict in the wider context of nuclear weapons possession and potential use, to point out how its conduct should affect public perception of such use, and the urgency for effective nuclear arms control measures including a determined resolve to implement the United Nations' 2017 Treaty on the Prevention of Nuclear Weapons.

Invited Commentary: Ionizing Radiation and Future Reproductive Health-Old Cohorts Still Deserve Attention.

Radiation from nuclear weapons or power plants has caused great concern among the public-concern that needs to be addressed with the best available data. Among the concerns associated with ionizing radiation are possible serious and far-reaching effects on reproductive health. Relevant data that can be used to address these concerns are scarce. The Hiroshima and Nagasaki bombings of World War II and the 1986 Chernobyl disaster in Ukraine are probably among the most dramatic and important sources of information on health effects, but much of the information is historical, and the exposed cohorts are getting old. In their accompanying article, Yamada et al. (Am J Epidemiol. 2021;190(11):2323-2333) revisit data on reproductive health outcomes in survivors of the Hiroshima and Nagasaki bombings during the years after the blasts. Exposure levels were very high, but after Yamada et al.'s reanalysis, effect estimates were low, and the evidence for overall effects on birth defects and perinatal mortality is still weak. The authors acknowledge that their data have limitations and that the generalizability of the findings is limited by the devastating conditions that prevailed in the 2 Japanese cities after the blasts.

Radiation effects on human heredity.

In experimental organisms such as fruit flies and mice, increased frequencies in germ cell mutations have been detected following exposure to ionizing radiation. In contrast, there has been no clear evidence for radiation-induced germ cell mutations in humans that lead to birth defects, chromosome aberrations, Mendelian disorders, etc. This situation exists partly because no sensitive and practical genetic marker is available for human studies and also because the number of people exposed to large doses of radiation and subsequently having offspring was small until childhood cancer survivors became an important study population. In addition, the genome of apparently normal individuals seems to contain large numbers of alterations, including dozens to hundreds of nonfunctional alleles. With the number of mutational events in protein-coding genes estimated as less than one per genome after 1 gray (Gy) exposure, it is unsurprising that genetic effects from radiation have not yet been detected conclusively in humans.

High-Resolution Tritium Profile in an Ice Core from Camp Century, Greenland.

We measure 3H in an ice core from Camp Century. The temporal distribution of 3H concentration in the ice core corresponds generally well with the historical record of explosive yields of atmospheric nuclear weapons tests. Maximum 3H values observed in 1962-1963 are comparable to those in ice core or precipitation in many other locations in the Northern Hemisphere. There is no indication that significant 3H contamination was locally released into the air during the operation of the Camp Century reactor. It is, however, somewhat surprising that several prominent 3H peaks are still observed after 1980. We suggest that these are associated with airborne 3H releases from the civil nuclear industry. A wavelet analysis during 1970-2017 indicates the primary frequency of variability in the 3H record is annual 3H peaks. These annual peaks can be combined with the 3H spikes from global fallout of known nuclear weapons tests to benchmark and evaluate theoretical ice core dating scales back to the 1950s. A positive correlation is observed between annual 3H average concentration and variability of Arctic Oscillation (AO). This highlights the value of 3H as a potential tracer for air masses and airborne pollutants in the Arctic.

Radiation effects on atherosclerosis in atomic bomb survivors: a cross-sectional study using structural equation modeling.

Past reports indicated that total-body irradiation at low to moderate doses could be responsible for cardiovascular disease risks, but the mechanism remains unclear. The purpose of this study was to investigate the association between radiation exposure and atherosclerosis, an underlying pathology of cardiovascular diseases, in the Japanese atomic bomb survivors. We performed a cross-sectional study measuring 14 clinical-physiological atherosclerosis indicators during clinical exams from 2010 to 2014 in 3274 participants of the Adult Health Study cohort. Multivariable analyses were performed by using a structural equation model with latent factors representing underlying atherosclerotic pathologies: (1) arterial stiffness, (2) calcification, and (3) plaque　as measured with indicators chosen a priori on the basis of clinical-physiological knowledge. Radiation was linearly associated with calcification (standardized coefficient per Gy 0.15, 95 % confidence interval: CI [0.070, 0.23]) and plaque (0.11, 95 % CI [0.029, 0.20]), small associations that were comparable to about 2 years of aging per Gy of radiation exposure, but not with arterial stiffness (0.036, 95 % CI [- 0.025, 0.095]). The model fitted better and had narrower confidence intervals than separate ordinary regression models explaining individual indicators independently. The associations were less evident when the dose range was restricted to a maximum of 2 or 1 Gy. By combining individual clinical-physiological indicators that are correlated because of common, underlying atherosclerotic pathologies, we found a small, but significant association of radiation with atherosclerosis.

Development of a Potential Facility Risk Index for Radiological Security.

Given the threat of radiological and nuclear terrorism, it is imperative to understand and evaluate the security risk of radioactive sources. In this context, risk assessment is a function of threat, vulnerability, and consequences. Currently, no broad risk index exists for radiological facilities, such as healthcare centers and universities. This study aims to develop and demonstrate a methodology to compute a potential facility risk index (PFRI) based on a probable loss event (LE) and loss magnitude (LM) resulting from a radiological dispersal device (RDD) attack. The threat component of the PFRI is devised as a utility function weighing the threat group attributes and RDD radioactive material preference. The principles of probabilistic risk assessment and pathway analysis are implemented to account for RDD radioactive material theft probabilities in different attack scenarios. Locational hazards and nuclear security culture are measured as a function of radiological facility vulnerability for LE. The LM of the attack, in the form of loss of life and economic damage, is then estimated to construct the PFRI. The methodology is applied to a hypothetical healthcare facility with a single radioactive material asset. For this example, the PFRI resulted in a value of 2.0 (on a scale of 1-10), showing low risk to the facility. The development of the PFRI provides a risk analysis tool that may be useful in making decisions for radiological security improvements.

"Un-Promethean" science and the future of humanity: Heidegger's warning.

The twentieth-century German philosopher Martin Heidegger distinguished "meditative" (besinnlich) and "calculative" (rechnende) modes of thinking as a way of highlighting the problematique of modern technology and the limits of modern science. In doing so he also was prescient to recognize, in 1955, that the most significant danger to the future of humanity are developments in molecular biology and biotechnology, in contrast to the post-World War global threat of thermonuclear weapons. These insights are engaged here in view of recent discussion of the need for international regulation of heritable human genome editing and the announcement in 2018 of the birth of the world's first gene-edited babies in China. Heidegger's call for meditative thinking requires modern medicine and the life sciences to appropriate the phenomenological conception of the human "way to be" (Seinsweise) such that it is not restricted to the "present-at-hand" (vorhanden) physiology and pathology of the human body (Körper).