2,548 research outputs found
Life Support and Environmental Monitoring International System Maturation Team Considerations
Human exploration of the solar system is an ambitious goal. Future human missions to Mars or other planets will require the cooperation of many nations to be feasible. Exploration goals and concepts have been gathered by the International Space Exploration Coordination Group (ISECG) at a very high level, representing the overall goals and strategies of each participating space agency. The Global Exploration Roadmap published by ISECG states that international partnerships are part of what drives the mission scenarios. It states "Collaborations will be established at all levels (missions, capabilities, technologies), with various levels of interdependency among the partners." To make missions with interdependency successful, technologists and system experts need to share information early, before agencies have made concrete plans and binding agreements. This paper provides an overview of possible ways of integrating NASA, ESA, and JAXA work into a conceptual roadmap of life support and environmental monitoring capabilities for future exploration missions. Agencies may have immediate plans as well as long term goals or new ideas that are not part of official policy. But relationships between plans and capabilities may influence the strategies for the best ways to achieve partner goals. Without commitments and an organized program like the International Space Station, requirements for future missions are unclear. Experience from ISS has shown that standards and an early understanding of requirements are an important part of international partnerships. Attempting to integrate systems that were not designed together can create many problems. Several areas have been identified that could be important to discuss and understand early: units of measure, cabin CO2 levels, and the definition and description of fluids like high purity oxygen, potable water and residual biocide, and crew urine and urine pretreat. Each of the partners is exploring different kinds of technologies. Different specific parameters may important to define or explore possible ranges depending on the system concepts. Early coordination between technology developers can create new possibilities for collaboration, and provide input to determine what combined options may provide the best overall system architecture
Hepatocyte-like cells differentiated from human induced pluripotent stem cells: Relevance to cellular therapies
AbstractMaturation of induced pluripotent stem cells (hiPSCs) to hepatocyte-like cells (HLCs) has been proposed to address the shortage of human hepatocytes for therapeutic applications. The purpose of this study was to evaluate hiPSCs, HLCs and hepatocytes, all of human origin, in terms of performance metrics of relevance to cell therapies. hiPSCs were differentiated to HLCs in vitro using an established four-stage approach. We observed that hiPSCs had low oxygen consumption and possessed small, immature mitochondria located around the nucleus. With maturation to HLCs, mitochondria showed characteristic changes in morphology, ultrastructure, and gene expression. These changes in mitochondria included elongated morphology, swollen cristae, dense matrices, cytoplasmic migration, increased expression of mitochondrial DNA transcription and replication-related genes, and increased oxygen consumption. Following differentiation, HLCs expressed characteristic hepatocyte proteins including albumin and hepatocyte nuclear factor 4-alpha, and intrinsic functions including cytochrome P450 metabolism. But HLCs also expressed high levels of alpha fetoprotein, suggesting a persistent immature phenotype or inability to turn off early stage genes. Furthermore, the levels of albumin production, urea production, cytochrome P450 activity, and mitochondrial function of HLCs were significantly lower than primary human hepatocytes.Conclusion- hiPSCs offer an unlimited source of human HLCs. However, reduced functionality of HLCs compared to primary human hepatocytes limits their usefulness in clinical practice. Novel techniques are needed to complete differentiation of hiPSCs to mature hepatocytes
Results from New Zealand's 2018 Report Card on Physical Activity for Children and Youth.
In New Zealand (NZ), 88% of health loss is now caused by non-communicable diseases, in part attributed to low levels of physical activity (PA) and high levels of inactivity, and the downstream impacts of these, including suboptimal blood glucose profiles, body size, and blood pressure.1 While the NZ 2016 PA Report Card on Physical Activity for Children and Youth2 revealed relatively high levels of PA, approximately one-third of NZ children and youth did not meet PA recommendations of ≥60 minutes of moderate-to-vigorous physical activity (MVPA) per day. The purpose of this paper is to summarize the methods for grade calculation and results of the 2018 update of the PA Report Card for NZ
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Results from New Zealand's 2018 Report Card on Physical Activity for Children and Youth.
In New Zealand (NZ), 88% of health loss is now caused by non-communicable diseases, in part attributed to low levels of physical activity (PA) and high levels of inactivity, and the downstream impacts of these, including suboptimal blood glucose profiles, body size, and blood pressure.1 While the NZ 2016 PA Report Card on Physical Activity for Children and Youth2 revealed relatively high levels of PA, approximately one-third of NZ children and youth did not meet PA recommendations of ≥60 minutes of moderate-to-vigorous physical activity (MVPA) per day. The purpose of this paper is to summarize the methods for grade calculation and results of the 2018 update of the PA Report Card for NZ
New Panoramic View of CO and 1.1 mm Continuum Emission in the Orion A Molecular Cloud. I. Survey Overview and Possible External Triggers of Star Formation
We present new, wide and deep images in the 1.1 mm continuum and the
CO (=1-0) emission toward the northern part of the Orion A Giant
Molecular Cloud (Orion-A GMC). The 1.1 mm data were taken with the AzTEC camera
mounted on the Atacama Submillimeter Telescope Experiment (ASTE) 10 m telescope
in Chile, and the CO (=1-0) data were with the 25 beam receiver
(BEARS) on the NRO 45 m telescope in the On-The-Fly (OTF) mode. The present
AzTEC observations are the widest (\timeform{1.D7}
\timeform{2.D3}, corresponding to 12 pc 17 pc) and the
highest-sensitivity (9 mJy beam) 1.1 mm dust-continuum imaging of
the Orion-A GMC with an effective spatial resolution of 40\arcsec. The
CO (=1-0) image was taken over the northern \timeform{1D.2}
\times\timeform{1D.2} (corresponding 9 pc 9 pc) area with a
sensitivity of 0.93 K in , a velocity resolution of 1.0 km
s, and an effective spatial resolution of 21\arcsec. With these data,
together with the MSX 8 m, Spitzer 24 m and the 2MASS data, we have
investigated the detailed structure and kinematics of molecular gas associated
with the Orion-A GMC and have found evidence for interactions between molecular
clouds and the external forces that may trigger star formation. Two types of
possible triggers were revealed; 1) Collision of the diffuse gas on the cloud
surface, particularly at the eastern side of the OMC-2/3 region, and 2)
Irradiation of UV on the pre-existing filaments and dense molecular cloud
cores. Our wide-field and high-sensitivity imaging have provided the first
comprehensive view of the potential sites of triggered star formation in the
Orion-A GMC.Comment: 32 pages, 20 figures, accepted for publication in PAS
Lack of Aquaporin 3 in bovine erythrocyte membranes correlates with low glycerol permeation
NOTICE: this is the author’s version of a work that was accepted for publication in Biochemical and Biophysical Research Communications. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Biochemical and Biophysical Research Communications. May 2011; 408 (3): 477-481.In general, erythrocytes are highly permeable to water, urea and glycerol. However, expression of aquaporin isoforms in erythrocytes appears to be species characteristic. In the present study, human (hRBC) and bovine (bRBC) erythrocytes were chosen for comparative studies due to their significant difference in membrane glycerol permeability.
Osmotic water permeability (Pf) at 23 ºC was (2.89 ± 0.37) × 10-2 and (5.12 ± 0.61) × 10-2 cm s-1 for human and bovine cells respectively, with similar activation energies for water transport. Glycerol permeability (Pgly) for human ((1.37 ± 0.26) × 10-5 cm s-1) differed in three orders of magnitude from bovine erythrocytes ((5.82 ± 0.37) ×10-8 cm s-1) that also showed higher activation energy for glycerol transport. When compared to human, bovine erythrocytes showed a similar expression pattern of AQP1 glycosylated forms on immunoblot analysis, though in slight higher levels, which could be correlated with the 1.5-fold larger Pf found. However, AQP3 expression was not detectable. Immunofluorescence analysis confirmed the absence of AQP3 expression in bovine erythrocyte membranes.
In conclusion, lack of AQP3 in bovine erythrocytes points to the lipid pathway as responsible for glycerol permeation and explains the low glycerol permeability and high Ea for transport observed in ruminants
Quantum Chaos: Reduced Density Matrix Fluctuations in Coupled Systems
Following a recent work (briefly reviewed below) we consider temporal
fluctuations in the reduced density matrix elements for a coupled system
involving a pair of kicked rotors as also one made up of a pair of Harper
Hamiltonians. These dynamical fluctuations are found to constitute a reliable
indicator of the degree of chaos in the quantum dynamics, and are related to
stationary features like the eigenvalue and eigenvector distributions of the
system under consideration. A brief comparison is made with the evolution of
the reduced distribution function in the classical phase space.Comment: 19 pages, 13 figures, elsart styl
Implications and consequences of ferromagnetism universally exhibited by inorganic nanoparticles
Occurrence of surface ferromagnetism in inorganic nanoprticles as a universal
property not only explains many of the unusual magnetic features of oxidic thin
films, but also suggests its possible use in creating new materials, as
exemplified by multiferroic BaTiO3 nanoparticles. While the use of Mn-doped ZnO
and such materials in spintronics appears doubtful, it is possible to have
materials exhibiting coexistence of (bulk) superconductivity with (surface)
ferromagnetism.Comment: 11 pages, 3 figures, 1 tabl
Detection of Strong Millimeter Emission from the Circumstellar Dust Disk Around V1094 Sco: Cold and Massive Disk around a T Tauri Star in a Quiescent Accretion Phase?
We present the discovery of a cold massive dust disk around the T Tauri star
V1094 Sco in the Lupus molecular cloud from the 1.1 millimeter continuum
observations with AzTEC on ASTE. A compact (320 AU) continuum
emission coincides with the stellar position having a flux density of 272 mJy
which is largest among T Tauri stars in Lupus. We also present the detection of
molecular gas associated with the star in the five-point observations in
CO J=3--2 and CO J=3--2. Since our CO and CO
observations did not show any signature of a large-scale outflow or a massive
envelope, the compact dust emission is likely to come from a disk around the
star. The observed SED of V1094 Sco shows no distinct turnover from near
infrared to millimeter wavelengths, which can be well described by a flattened
disk for the dust component, and no clear dip feature around 10 \micron
suggestive of absence of an inner hole in the disk. We fit a simple power-law
disk model to the observed SED. The estimated disk mass ranges from 0.03 to
0.12 M_\sun, which is one or two orders of magnitude larger than the
median disk mass of T Tauri stars in Taurus.Comment: 18 pages, 4 figures, accepted for publication in Ap
An Assessment of Variants in the Professional Judgement of Geomorphologically-based Channel Types.
River classification is a useful tool for researchers and managers wishing to organise, simplify and understand the forms and processes within freshwater systems. Many classifications require surveyors to classify reaches into specific channel types in a field environment. Channel types should be identifiable based on a field surveyor’s
judgement of channel characteristics and landscape settings; these include channel planform, valley confinement, dominant bed material, and/or instream geomorphic features (e.g. gravel bars). Accurate classification of reaches into the correct channel
type is important to ensure consistency in management strategies, and to assess the impact of engineering activities on the physical and ecological status of rivers. In this paper, we examine the variation in professional judgement of geomorphologically based channel types by scientists with different disciplinary backgrounds, and varying levels of involvement in classification systems using a photo-questionnaire. Results indicate that there can be a large level of discrepancy in typing rivers; the choice of the modal channel type for each reach varied between 25.9% and 75.1% of the respondent selections. There were also differences in the level of agreement between
earth scientists (with hydrogeomorphological or geological training), ecological scientists (with freshwater biology training) and practitioners involved in river conservation and management. A high level of experience in classification systems translates to a lower number of channel types being chosen per reach. In response to these results, the use of a photographic approach to typing needs to be fully tested and users fully trained before operational use. Furthermore, we advocate that designers of
geomorphic typologies should aim to have a representative and workable number of classes within a typology with an emphasis for rationalisation of classes rather than expansion of numbers
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