The Potential of Fasting and Caloric Restriction to Mitigate Radiation Damage—A Systematic Review

Detrimental health effects from ionizing radiation to the living being is one of the key concerns identified and addressed by Radiation Protection institutions, nationally and internationally on Earth and for human spaceflight. Thus, new methods for mitigating the adverse effects of ionizing radiation are urgently needed for terrestrial health and deep space exploration. Caloric restriction and (intermittent-) fasting have been reported to elicit a variety of immediate and long-term physiological effects. The rapidly growing body of evidence of research studies investigating the effects of caloric restriction and dietary fasting points towards a multitude of health benefits affecting numerous physiological systems. Therefore, a systematic literature review was performed to evaluate the evidence of caloric restriction and dietary fasting on the physiological response to ionising radiation in humans and animals. All experimental studies in humans, animals and eukaryotic cell lines available in PubMed, Cochrane library and specialised databases were searched comparing irradiation post-caloric restriction or fasting to a non-nutritionally restricted control group on a broad range of outcomes from molecular to clinical responses. The initial search yielded 2653 records. The final analysis included 11 studies. Most studies investigated the survival rate or cancer occurrence in animals. Included studies did not reveal any benefit from pre exposure caloric restriction, except when performed with post radiation caloric restriction. However, the effects of pre-exposure fasting suggest increased resilience to ionizing radiation

Innovations in (U–Th)/He, Fission Track, and Trapped Charge Thermochronometry with Applications to Earthquakes, Weathering, Surface‐Mantle Connections, and the Growth and Decay of Mountains

A transformative advance in Earth science is the development of low‐temperature thermochronometry to date Earth surface processes or quantify the thermal evolution of rocks through time. Grand challenges and new directions in low‐temperature thermochronometry involve pushing the boundaries of these techniques to decipher thermal histories operative over seconds to hundreds of millions of years, in recent or deep geologic time and from the perspective of atoms to mountain belts. Here we highlight innovation in bedrock and detrital fission track, (U–Th)/He, and trapped charge thermochronometry, as well as thermal history modeling that enable fresh perspectives on Earth science problems. These developments connect low‐temperature thermochronometry tools with new users across Earth science disciplines to enable transdisciplinary research. Method advances include radiation damage and crystal chemistry influences on fission track and (U–Th)/He systematics, atomistic calculations of He diffusion, measurement protocols and numerical modeling routines in trapped charge systematics, development of 4He/3He and new (U–Th)/He thermochronometers, and multimethod approaches. New applications leverage method developments and include quantifying landscape evolution at variable temporal scales, changes to Earth\u27s surface in deep geologic time and connections to mantle processes, the spectrum of fault processes from paleoearthquakes to slow slip and fluid flow, and paleoclimate and past critical zone evolution. These research avenues have societal implications for modern climate change, groundwater flow paths, mineral resource and petroleum systems science, and earthquake hazards

Implant-Based Breast Reconstruction after Mastectomy, from the Subpectoral to the Prepectoral Approach: An Evidence-Based Change of Mind?

Over the last years, prepectoral implant-based breast reconstruction has undergone a renaissance due to several technical advancements regarding mastectomy techniques and surgical approaches for the placement and soft tissue coverage of silicone implants. Initially abandoned due to the high incidence of complications, such as capsular contraction, implant extrusion, and poor aesthetic outcome, the effective prevention of these types of complications led to the prepectoral technique coming back in style for the ease of implant placement and the conservation of the pectoralis muscle function. Additional advantages such as a decrease of postoperative pain, animation deformity, and operative time contribute to the steady gain in popularity. This review aims to summarize the factors influencing the trend towards prepectoral implant-based breast reconstruction and to discuss the challenges and prospects related to this operative approach

The Potential of Physical Exercise to Mitigate Radiation Damage—A Systematic Review

There is a need to investigate new countermeasures against the detrimental effects of ionizing radiation as deep space exploration missions are on the horizon.Objective: In this systematic review, the effects of physical exercise upon ionizing radiation-induced damage were evaluated.Methods: Systematic searches were performed in Medline, Embase, Cochrane library, and the databases from space agencies. Of 2,798 publications that were screened, 22 studies contained relevant data that were further extracted and analyzed. Risk of bias of included studies was assessed. Due to the high level of heterogeneity, meta-analysis was not performed. Five outcome groups were assessed by calculating Hedges' g effect sizes and visualized using effect size plots.Results: Exercise decreased radiation-induced DNA damage, oxidative stress, and inflammation, while increasing antioxidant activity. Although the results were highly heterogeneous, there was evidence for a beneficial effect of exercise in cellular, clinical, and functional outcomes.Conclusions: Out of 72 outcomes, 68 showed a beneficial effect of physical training when exposed to ionizing radiation. As the first study to investigate a potential protective mechanism of physical exercise against radiation effects in a systematic review, the current findings may help inform medical capabilities of human spaceflight and may also be relevant for terrestrial clinical care such as radiation oncology.</jats:p

Effects of UV radiation on aquatic ecosystems and interactions with climate change

The health of freshwater and marine ecosystems is critical to life on Earth. The impact of solar UV-B radiation is one potential stress factor that can have a negative impact on the health of certain species within these ecosystems. Although there is a paucity of data and information regarding the effect of UV-B radiation on total ecosystem structure and function, several recent studies have addressed the effects on various species within each trophic level. Climate change, acid deposition, and changes in other anthropogenic stressors such as pollutants alter UV exposure levels in inland and coastal marine waters. These factors potentially have important consequences for a variety of aquatic organisms including waterborne human pathogens. Recent results have demonstrated the negative impacts of exposure to UV-B radiation on primary producers, including effects on cyanobacteria, phytoplankton, macroalgae and aquatic plants. UV-B radiation is an environmental stressor for many aquatic consumers, including zooplankton, crustaceans, amphibians, fish, and corals. Many aquatic producers and consumers rely on avoidance strategies, repair mechanisms and the synthesis of UV-absorbing substances for protection. However, there has been relatively little information generated regarding the impact of solar UV-B radiation on species composition within natural ecosystems or on the interaction of organisms between trophic levels within those ecosystems. There remains the question as to whether a decrease in population size of the more sensitive primary producers would be compensated for by an increase in the population size of more tolerant species, and therefore whether there would be a net negative impact on the absorption of atmospheric carbon dioxide by these ecosystems. Another question is whether there would be a significant impact on the quantity and quality of nutrients cycling through the food web, including the generation of food proteins for humans. Interactive effects of UV radiation with changes in other stressors, including climate change and pollutants, are likely to be particularly important.Fil: Häder, D. P.. No especifíca;Fil: Helbling, Eduardo Walter. Fundación Playa Unión. Estación de Fotobiología Playa Unión; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Williamson, C. E.. Miami University; Estados UnidosFil: Worrest, R. C.. No especifíca

Nourishing the brain on deep space missions: nutritional psychiatry in promoting resilience

The grueling psychological demands of a journey into deep space coupled with ever-increasing distances away from home pose a unique problem: how can we best take advantage of the benefits of fresh foods in a place that has none? Here, we consider the biggest challenges associated with our current spaceflight food system, highlight the importance of supporting optimal brain health on missions into deep space, and discuss evidence about food components that impact brain health. We propose a future food system that leverages the gut microbiota that can be individually tailored to best support the brain and mental health of crews on deep space long-duration missions. Working toward this goal, we will also be making investments in sustainable means to nourish the crew that remains here on spaceship Earth

Auswertung von funktionellen Gruppen des Phytoplanktons aus hyperspektralen Satellitendaten und ihre Anwendung für die Untersuchung der Dynamik des Phytoplanktons in ausgewählten Meeresregionen.

Phytoplankton play a unique role in the marine ecosystem as the basis of the marine food-web. They are the main drivers of the biogeochemical cycles in the ocean, as well as influencing the ocean-atmosphere exchanges of carbon dioxide and particular gases and particles. Based on these exchanges, phytoplankton influence the chemistry of atmosphere and the balance of global climate. Moreover, through interaction with light (absorption and scattering), phytoplankton have a significant impact on the underwater optics, being also responsible for the variations in ocean color. However, performing all these roles depends significantly on the type of phytoplankton, as indeed they comprise of a wide range of species and groups, with different capabilities and different distribution patterns in the World Ocean. Therefore, distinguishing between different types of phytoplankton is important to improve the knowledge of their actual roles in the ocean and climate system. As the spectral patterns of light absorption (essential for photosynthesis) vary among different groups of phytoplankton, the backscatter light from ocean preserves the spectral fingerprints of the inhabitant groups of phytoplankton. This feature can be used to determine remotely different types of phytoplankton. The purpose of this PhD-work was to improve a phytoplankton retrieval method, which was established to distinguish quantitatively major phytoplankton groups based on their absorption characteristics. The method, called PhytoDOAS, uses high spectrally resolved satellite data, provided by SCIAMACHY sensor. So far, by applying PhytoDOAS method to SCIAMACHY data, two main phytoplankton groups, diatoms and cyanobacteria, have been successfully distinguished. Through this work the method was improved to detect additionally coccolithophores, another important taxonomic group with significant biogeochemical functions. In this improvement, instead of the usual approach of the PhytoDOAS, which was based on single-target fitting, the simultaneous fitting of a certain set of phytoplankton groups was implemented within a wider wavelength window, thereby the new approach is called multi-target fit. Selection of the set of phytoplankton targets was according to the spectral analysis of absorption features of those groups that are most important with respect to the principal biogeochemical impacts, based on which marine microalgae are grouped as phytoplankton functional types, PFTs. The improved method was successfully tested through detecting independently reported blooms of coccolithophores, as well as by comparison of PhytoDOAS coccolithophores with global distributions of Particulate Inorganic Carbon (PIC), which is used as a proxy of coccolithophores. As the next step of this PhD-work, the results of the improved PhytoDOAS method were used to investigate temporal variations of coccolithophore blooms in selected regions. Eight years of SCIAMACHY data, from 2003 to 2010, were processed by the PhytoDOAS triple-target mode to monitor the biomass of coccolithophores in three oceanic regions, characterized by the frequent occurrence of large blooms. Then the PhytoDOAS results, as monthly mean time-series, were compared to appropriate satellite products, including the total phytoplankton biomass (total chl-a) from GlobColour data-set and the PIC distribution from MODIS-Aqua. To study the dynamics of coccolithophore blooms, the variations of coccolithophores, overall chl-a and PIC, as monthly mean time series, were investigated in the context of variations in the main oceanic geophysical parameters: sea-surface temperature (SST), mixed-layer depth (MLD) and surface wind speed. As a general result, it was observed that the inter-annual variations of the coccolithophore bloom cycles followed well the respective variations in the mentioned geophysical parameters, as they have been reported being associated with coccolithophore blooms. Observed anomalies were investigated based on the specific regional features of the geophysical conditions. Using the results of regional time series, the hypothesis that close coccolithophore blooms succeed the diatom blooms was roughly approved, suggesting, however, a weekly-based averaging of coccolithophores and diatoms for a more precise analysis. It has been frequently reported that high reflectance from surface waters in coccolithophore rich areas affects the performance of standard chl-a algorithms. The regional time series studies of this thesis indicated an underestimation of total chl-a by the standard algorithm during the time of occolithophore blooms. However, a comprehensive validation of the ocean color algorithms with in-situ phytoplankton data is needed to reach the final assessment of the short-comings

The relationship of lysosomal stability to radiation-induced delay of cell division in Tetrahymena pyriformis

Cell division in a heat synchronized Tetrahymena pyriformis (GL-I) cell can be delayed if the cell is exposed to X-irradiation (300 kVp, 20 mA, HVL = 0. 9 mm Cu, 25 R/ sec) prior to a critical time after the end of the synchronizing treatment (EST). At the critical time, the cells undergo a rapid transition from a state of being sensitive to being delayed to one of relative insensitivity. After this time, the coming division is delayed little if at all; that is, there is an "all or none" transition to insensitivity to division delay. However, the second division is delayed, indicating that damage has occurred. The transition point (median critical time) is determined by interpolating the time after EST at which a given radiation exposure splits a population of cells into 50 percent delayed and 50 percent not delayed. The transition point is dose dependent in that the larger the exposure, the later the transition point (31 minutes after EST for 3kR increasing gradually to 51 minutes after EST for 18.5 kR). The division delay response is correlated with a resorption of the developing new mouth as determined from silver stained cells fixed every ten minutes after EST. The length of time for the oral primordium to be resorbed increases as the dose increases and varies with the time of irradiation relative to the transition point. The all or none" nature of the division delay response and the fact that cells irradiated after the transition point seemingly "ignore" the radiation damage until the second generation, together suggest that the damage produced by the irradiation may or may .not trigger a cellular response that results in cell division delay and oral primordium resorption. These responses might suggest that preformed enzymes, possibly from lysosomes, could be involved. Therefore, cells were treated with a known lysosomal stabilizer (hydrocortisone) and a labilizer (vitamin A) continuously before, during, and after exposure to 7.5 kR of X-rays. Cells treated with hydrocortisone- 21- phosphate (5.0 mM) showed an earlier transition point (36.5 minutes after EST) whereas cells treated with vitamin A-acetate (0.2 mM) showed a later transition point (50.5 minutes after EST) relative to the transition point for untreated, irradiated cells (43 minutes after EST). The time of the transition for cells treated with a lysosomal stabilizer (depresses enzyme release) and 7.5 kR corresponds to the transition point for untreated cells irradiated with only 5.0 kR,suggesting less sensitivity. Conversely, the transition point for cells treated with a lysosomal labilizer (enhances enzyme release) and 7.5 kR corresponds to the time of transition for untreated cells exposed to 18.5 kR, suggesting greater sensitivity. However, in all cases, 7.5 kR delayed the divisions about the same amount, whether the agents were present or not, indicating that the agents do not act in a simple dose - modifying manner. The data are consistent with the hypothesis that irradiation produces damage that may or may .not trigger off a cellular response that leads to delay of division. The sensitivity of the cell to being triggered to delay division may involve lysosomes

ATS-6 engineering performance report. Volume 6: Scientific experiments

Evaluations include a very high resolution radiometer, a radio beacon experiment, environmental measurement experiments (EME), EME support hardware, EME anomalies and failures, EME results, and US/USSR magnetometer experiments

Time-resolved protein dynamics using x-ray crystallography and optical spectroscopy

Reversibly switchable fluorescent proteins (RSFPs) switch between a highly and weakly fluorescent state upon photoexcitation. This switching is known to be driven by reversible photoisomerisation and a change in protonation state of the chromophore. However, the exact sequence of events after optical excitation is unclear. In this thesis, time-resolved crystallography and vibrational spectroscopy are used to study the ultrafast dynamics of a new RSFP.  Time-resolved serial femtosecond crystallography (TR-SFX) is used to probe the trans/cis reaction and reveals ultrafast sub-Angstrom motions of the chromophore and surrounding hydrogen bonding network. The addition of a stokes pulse (shown to dump the excited state population) increases these displacements and allows assignment of the light-induced signals to a vibrationally excited electronic ground state structure instead of an excited state structure. Temperature analysis of the steady-state switching rates resolves an intermediate ground-state structure using conventional crystallography which supports the TR-SFX assignments. Ultrafast pump-probe vibrational spectroscopy confirms that excited state photoisomerisation occurs (~70 ps), proceeded by rearrangement of a nearby arginine residue (~7 ps) with deprotonation (trans-neutral/cis-anion) occurring between 2 ns - 1 ms. An additional dump pulse is then shown to repress product formation and reforms the ground state, further supporting the structural observations of the pump-dump-probe crystallography measurements. These results improve our understanding of photoswitching in RSFPs and have important implications for structural assignments in future TR-SFX experiments. Time-resolved serial synchrotron crystallography (TR-SSX) is an accessible and emerging technique for studying protein dynamics on millisecond timescales. Here, the trans/cis isomerisation of an RSFP is probed at 10 ms with a range of pump intensities to demonstrate precise control of the cis-state formation yields. The population transfer is resolved crystallographically using quantitative analysis of the occupancy, showing excellent agreement with optical flash-photolysis measurements. The issue of X-ray induced heating, which leads to partial thermal recovery, is also addressed. A temperature increase of 82-112 K is extracted for the fixed-target sample delivery used, which should be accounted for in all future TR-SSX experiments. Finally, the effect of pH on the protonation step is investigated by studying a RSFP mutant with a destabilised ground state conformation. Structural and spectroscopic evidence is presented for a new class of reaction at low pH, involving a cis-neutral/trans-cation isomerisation, in contrasts to the typical cis-anion/trans-neutral reaction at neutral pH. These steady-state observations expand our understanding of acid/base equilibria in the photoreactions of RSFPs.Open Acces