5578 research outputs found
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Survivability and life support in sealed mini-ecosystems with simulated planetary soils
No full textEstablishing a sustainable life-support system for space exploration is a formidable challenge due to the vast distances, high costs, and environmental differences from Earth. Building upon the lessons from the Biosphere 2 experiment, we introduce the novel “Ecosphere” and “Biosealed” systems, self-sustaining ecosystems within customizable, enclosed containers. These systems incorporate terrestrial ecosystems and groundwater layers, offering a potential model for transplanting Earth-like biomes to extraterrestrial environments. Over 4 years, we conducted rigorous experiments and analyses to understand the dynamics of these enclosed ecosystems. We successfully mitigated moisture deficiency, a major obstacle to plant growth, by incorporating groundwater layers. Additionally, we quantified microbial communities proliferating in specific soils, including simulated lunar and Ryugu asteroid regolith, enhance plant cultivation in space environments. Metagenomic analysis of these simulated space soils revealed diverse microbial populations and their crucial role in plant growth and ecosystem stability. Notably, we identified symbiotic relationships between plants and Cyanobacteria, enhancing oxygen production, and demonstrated the potential of LED lighting as an alternative light source for plant cultivation in sun-limited space missions. We also confirmed the survival of fruit flies within these systems, relying on plant-produced oxygen and photosynthetic bacteria. Our research provides a comprehensive framework for developing future space life-support systems. The novelty of our work lies in the unique design of our enclosed ecosystems, incorporating groundwater layers and simulated extraterrestrial soils, and the detailed analysis of microbial communities within these systems. These findings offer valuable insights into the challenges and potential solutions for establishing sustainable human habitats in space, including the importance of microbial management and potential health concerns related to microbial exposure.journal articl
Comparison of force and timing control in periodic isometric leg extension
No full textBackground: In daily life and sports activities, the regulation of muscle force and timing is often not controlled independently, rather the appropriate amount of force is controlled simultaneously with appropriate timing. However, which of the two variables, force or timing, is more difficult to control remains unclear.
Objective: We aimed to investigate the difficulty in the accurate control of force and timing, simultaneously. By setting target levels for force and timing interval, with both target lines presented, none of them presented, or only one of the target lines for force or timing interval presented, we directly examined and identified which variable is more important. Methods: Participants were asked to produce periodic isometric knee extension force using their right leg. The following four tasks were established: 20 %MVF-1000 ms task (20 % maximum voluntary force [MVF] at 1000 ms intervals), 20 %MVF-2000 ms task (20 % MVF at 2000 ms intervals), 40 %MVF-1000 ms task (40 % MVF at 1000 ms intervals), and 40 %MVF-2000 ms task (40 % MVF at 2000 ms intervals). Moreover, the participants performed four tasks under the following four conditions based on target line presentation: Both variables condition (force and interval lines presented), force condition (only force line presented), interval condition (only interval line presented), and no variable condition (neither force nor interval lines presented). The recorded force data were analyzed.
Results: Regarding the force factor, the error of the interval and no variable conditions was greater than that of the both variables and force conditions. As for the interval factor, the error was greater when the target interval line was not presented (force and no variable conditions) than when it was presented (both variables and interval conditions), and it exceeded the target interval in the 1000 ms task, whereas it was shorter than the target in terval in the 2000 ms task. Except for the force condition, the force factor showed significantly greater absolute errors when the target level was set as 100 %, compared to the interval factor.
Conclusions: The control of force was found to be more difficult than that of timing, based on aspects relating to accuracy and reproducibility.journal articl
Fast and Stable Responses during Decision Making Require Strong Inhibitory Processes in Soccer Players
No full textQuick decision making is a vital factor for a successful pass in soccer games. Many previous studies of decision making in soccer focused on motor execution, but inhibitory processing has remained unclear. This study aimed to clarify the differences in motor execution and inhibitory among Japanese collegiate soccer players with different skill levels. We evaluated the behavioral data and event-related potentials in the high-skilled, low-skilled, and novice groups during the Go/No-go and pass choice reaction tasks. The reaction time (RT) was significantly shorter in the high group than in the novice group, and RT variability was small in the high group. The amplitude of the N2 component was significantly larger in the high group than in the low and novice groups, and the latency of the P3 component was significantly shorter in the high and low groups than in the novice group during the pass choice reaction task. The subtracted No-go N2 amplitude was also significantly larger in the high and low groups than in the novice group, and correlations existed between the RT, RT variability, and the subtracted No-go N2 amplitude during these tasks. These data indicate that soccer players’ behavioral responses and inhibition processing decision-making activities are associated with skill levels.Correction published on 14 February 2025, see Brain Sci. 2025, 15(2), 193.
https://doi.org/10.3390/brainsci15020193journal articl
Climate Change−Energy Security Nexus in ASEAN: Quantitative text analysis using energy ministerial meeting statements
No full textThe Association of Southeast Asian Nations (ASEAN) faces the urgent environmental challenge
of reducing CO2 emissions from fossil fuels to limit the damage from climate change. Meanwhile,
in addition to the climate change issues, ASEAN has the critical responsibility of ensuring energy
security, including the need to supply stable and affordable energy. To determine how this climate
change−energy security nexus has evolved in ASEAN, we examine statement documents released
by the ASEAN Minister on Energy Meetings and its associated meetings. Our quantitative text
analysis shows that: (1) as the discussions towards achieving carbon neutrality have progressed,
the climate change issues have been increasingly highlighted, (2) the decarbonization of coal and
diversification to renewable energy has received increasing attention, while energy efficiency and
conservation discussions have stalled, (3) innovative technologies such as clean coal, renewable
energy, and hydrogen have gained strong attention. Our analysis also finds that individual energy
ministerial meetings feature different attitudes toward the climate change−energy security nexus,
including in terms of their selection of energy technologies. Our study provides an opportunity
to reflect on the direction that ASEAN’s climate change and energy policies should take in future.journal articl
Transcriptional responses to salinity‐induced changes in cell wall morphology of the euryhaline diatom Pleurosira laevis
No full textDiatoms are unicellular algae with morphologically diverse silica cell walls, which are called frustules. The mechanism of frustule morphogenesis has attracted attention in biology and nanomaterials engineering. However, the genetic regulation of the morphology remains unclear. We therefore used transcriptome sequencing to search for genes involved in frustule morphology in the centric diatom Pleurosira laevis, which exhibits morphological plasticity between flat and domed valve faces in salinity 2 and 7, respectively. We observed differential expression of transposable elements (TEs) and transporters, likely due to osmotic response. Up-regulation of mechanosensitive ion channels and down-regulation of Ca2+-ATPases in cells with flat valves suggested that cytosolic Ca2+ levels were changed between the morphologies. Calcium signaling could be a mechanism for detecting osmotic pressure changes and triggering morphological shifts. We also observed an up-regulation of ARPC1 and annexin, involved in the regulation of actin filament dynamics known to affect frustule morphology, as well as the up-regulation of genes encoding frustule-related proteins such as BacSETs and frustulin. Taken together, we propose a model in which salinity-induced morphogenetic changes are driven by upstream responses, such as the regulation of cytosolic Ca2+ levels, and downstream responses, such as Ca2+-dependent regulation of actin dynamics and frustule-related proteins. This study highlights the sensitivity of euryhaline diatoms to environmental salinity and the role of active cellular processes in controlling gross valve morphology under different osmotic pressures.journal articl
Time-Resolved Probing of the Iodobenzene C-Band Using XUV-Induced Electron Transfer Dynamics
No full textTime-resolved extreme ultraviolet spectroscopy was used to investigate photodissociation within the iodobenzene C-band. The carbon–iodine bond of iodobenzene was photolyzed at 200 nm, and the ensuing dynamics were probed at 10.3 nm (120 eV) over a 4 ps range. Two product channels were observed and subsequently isolated by using a global fitting method. Their onset times and energetics were assigned to distinct electron transfer dynamics initiated following site-selective ionization of the iodine photoproducts, enabling the electronic states of the phenyl fragments to be identified using a classical over-the-barrier model for electron transfer. In combination with previous theoretical work, this allowed the corresponding neutral photochemistry to be assigned to (1) dissociation via the 7B2, 8A2, and 8B1 states to give ground-state phenyl, Ph(X), and spin–orbit excited iodine and (2) dissociation through the 7A1 and 8B2 states to give excited-state phenyl, Ph(A), and ground-state iodine. The branching ratio was determined to be 87 ± 4% Ph(X) and 13 ± 4% Ph(A). Similarly, the corresponding amount of energy deposited into the internal phenyl modes in these channels was determined to be 44 ± 10 and 65 ± 21%, respectively, and upper bounds to the channel rise times were found to be 114 ± 6 and 310 ± 60 fs.journal articl
Rainbow scattering pattern of fast ions by graphene sheet
No full textIn this study, we have observed the scattering pattern of a 0.5 MeV C+ beam passing through a monolayer graphene and compared it with the simulated one by a classical orbital calculation under the ZBL potential.
Since the monolayer graphene is a single layer consisting of honeycomb structures constituted of carbonatoms, the fast ion should be scattered only once under a potential generated by the honeycombed carbons, so the transmitted ions undergo the rainbow scattering. Consequently, the scattering with the monolayer graphene allows us to explore the interaction between fast ions and atoms avoiding the multiple scattering.
The classical orbital simulations under the ZBL potentials have been qualitatively agreed with the experimental scattering pattern, which measured as two- and one-dimensional intensity distributions of transmitted ions through monolayer graphene. However, there were quantitative discrepancies. By introducing the concept of effective nuclear charge into the potentials used in the simulations, we were able to quantitatively replicate the experimental results. We compare the simulations with experimental observations of rainbow scattering to gain insight into the interaction potential between ions and graphene.journal articl
Prolongations, invariants, and fundamental identities of geometric structures
No full textWorking in the framework of nilpotent geometry, we give a unified scheme for the equivalence problem of geometric structures which extends and integrates the earlier works by Cartan, Singer-Sternberg, Tanaka, and Morimoto.
By giving a new formulation of the higher order geometric structures and the universal frame bundles, we reconstruct the step prolongation of Singer-Sternberg and Tanaka. We then investigate the structure function γ of the complete step prolongation of a proper geometric structure by expanding it into components γ =κ +τ+σand establish the fundamental identities for κ, τ, σ. This then enables us to study the equivalence problem of geometric structures in full generality and to extend applications largely to the geometric structures which have not necessarily Cartan connections.
Among all we give an algorithm to construct a complete system of invariants for any higher order proper geometric structure of constant symbol by making use of eneralized Spencer cohomology group associated to the symbol of the geometric structure. We then discuss thoroughly the equivalence problem for geometric structure in both cases of infinite and finite type.
We also give a characterization of the Cartan connections by means of the structure function τ and make clear where the Cartan connections are placed in the perspective of the step prolongations.journal articl
Potential Molecular Mechanisms of Alcohol Use Disorder with Non-Coding RNAs and Gut Microbiota for the Development of Superior Therapeutic Application
No full textMany investigations have evaluated the expression of noncoding RNAs (ncRNAs) as well as their related molecular functions and biological machineries in individuals with alcohol dependence. Alcohol dependence may be one of the most prevailing psychological disorders globally, and its pathogenesis is intricate and inadequately comprehended. There is substantial evidence indicating significant links between multiple genetic factors and the development of alcohol dependence. In particular, the critical roles of ncRNAs have been emphasized in the pathology of mental illnesses, probably including alcohol dependence. In the comprehension of the action of ncRNAs and their machineries of modification, furthermore, they have emerged as therapeutic targets for a variety of psychiatric illnesses, including alcohol dependence. It is worth mentioning that the dysregulated expression of ncRNAs has been regularly detected in individuals with alcohol dependence. An in-depth knowledge of the roles of ncRNAs and m6A modification may be valuable for the development of a novel treatment against alcohol dependence. In general, a more profound understanding of the practical roles of ncRNAs might make important contributions to the precise diagnosis and/or actual management of alcohol dependence. Here, in this review, we mostly focused on up-to-date knowledge regarding alterations and/or modifications in the expression of ncRNAs in individuals with alcohol dependence. Then, we present prospects for future research and therapeutic applications with a novel concept of the engram system.journal articl
Deuterium Labeling of Isoaspartic and Isoglutamic Acids for Mass Spectrometry Analysis
No full textIsoaspartic acid (isoAsp) is a common protein modification that spontaneously arises from asparagine or aspartic acid and has been linked to various diseases and health conditions. However, current methods for identifying isoAsp sites in proteins often suffer from ambiguity and have not gained widespread adoption. We developed a novel method that exclusively labels isoAsp with deuterium. This method capitalizes on the unique structural characteristics of isoAsp residues, which possess a free α-carboxyl group and can form an oxazolone ring. Once the oxazolone ring forms, it facilitates racemization at the Cα-position, incorporating a deuteron from a D2O solvent. The sites of deuterium-incorporated isoAsp in proteins can be unequivocally determined by comparing the precursor and product ion masses of the peptides from proteins reacted in H2O and D2O. The effectiveness of this method has been demonstrated through its application to model proteins lysozyme and rituximab. Furthermore, we have confirmed that the isoAsp deuterium-labeling reaction efficiently labels both l- and d-isoAsp without distinction, as well as isoglutamic acid (isoGlu), for which no effective detection methods currently exist.journal articl