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space travel

David C Westerly, Reza A Behbahani, Brian Kavanagh, Arthur Liu, Moyed Miften, Natalie J Serkova, Quentin Diot
PURPOSE: Positron emission tomography (PET) imaging remains limited by the cost associated with on-site production of short half-life, positron emitting isotopes. In this work, we examine the use of a pulse line ion accelerator (PLIA) to accelerate protons for single-dose PET isotope production. METHODS: Time-domain electromagnetic field and particle-in-cell (PIC) simulations were performed for a 1.5 m PLIA structure modeled in CST Microwave Studio and Particle Studio software...
June 15, 2018: Medical Physics
Mizanur Rahman, Jennifer E Hewitt, Frank Van-Bussel, Hunter Edwards, Jerzy Blawzdziewicz, Nathaniel J Szewczyk, Monica Driscoll, Siva A Vanapalli
Muscle strength is a functional measure of quality of life in humans. Declines in muscle strength are manifested in diseases as well as during inactivity, aging, and space travel. With conserved muscle biology, the simple genetic model C. elegans is a high throughput platform in which to identify molecular mechanisms causing muscle strength loss and to develop interventions based on diet, exercise, and drugs. In the clinic, standardized strength measures are essential to quantitate changes in patients; however, analogous standards have not been recapitulated in the C...
June 12, 2018: Lab on a Chip
A Cangiani, E H Georgoulis, A Yu Morozov, O J Sutton
Understanding how patterns and travelling waves form in chemical and biological reaction-diffusion models is an area which has been widely researched, yet is still experiencing fast development. Surprisingly enough, we still do not have a clear understanding about all possible types of dynamical regimes in classical reaction-diffusion models, such as Lotka-Volterra competition models with spatial dependence. In this study, we demonstrate some new types of wave propagation and pattern formation in a classical three species cyclic competition model with spatial diffusion, which have been so far missed in the literature...
May 2018: Proceedings. Mathematical, Physical, and Engineering Sciences
Honghui Zhang, Andrew J Watrous, Ansh Patel, Joshua Jacobs
Human cognition requires the coordination of neural activity across widespread brain networks. Here, we describe a new mechanism for large-scale coordination in the human brain: traveling waves of theta and alpha oscillations. Examining direct brain recordings from neurosurgical patients performing a memory task, we found contiguous clusters of cortex in individual patients with oscillations at specific frequencies within 2 to 15 Hz. These oscillatory clusters displayed spatial phase gradients, indicating that they formed traveling waves that propagated at ∼0...
June 1, 2018: Neuron
Tongchen Wang, Ying Zhang, T C Yang, Huifang Chen, Wen Xu
Ocean acoustic tomography can be used based on measurements of two-way travel-time differences between the nodes deployed on the perimeter of the surveying area to invert/map the ocean current inside the area. Data at different times can be related using a Kalman filter, and given an ocean circulation model, one can in principle now cast and even forecast current distribution given an initial distribution and/or the travel-time difference data on the boundary. However, an ocean circulation model requires many inputs (many of them often not available) and is unpractical for estimation of the current field...
May 2018: Journal of the Acoustical Society of America
Laura Selbmann, Claudia Pacelli, Laura Zucconi, Ekaterina Dadachova, Ralf Moeller, Jean-Pierre de Vera, Silvano Onofri
The Antarctic black meristematic fungus Cryomyces antarcticus CCFEE 515 occurs endolithically in the McMurdo Dry Valleys of Antarctica, one of the best analogue for Mars environment on Earth. To date, this fungus is considered one of the best eukaryotic models for astrobiological studies and has been repeatedly selected for space experiments in the last decade. The obtained results are reviewed here, with special focus on responses to space relevant irradiation, UV radiation, and both sparsely and densely ionizing radiation, which represent the major injuries for a putative space-traveller...
June 2018: Fungal Biology
Birendra Mishra, Gregory W Lawson, Ryan Ripperdan, Laura Ortiz, Ulrike Luderer
Astronauts traveling in deep space are exposed to high-charge and energy (HZE) particles from galactic cosmic rays. We have previously determined that irradiation of adult female mice with iron HZE particles induces DNA double-strand breaks, oxidative damage and apoptosis in ovarian follicles, causing premature ovarian failure. These effects occur at lower doses than with conventional photon irradiation. Ovarian failure with resultant loss of negative feedback and elevated levels of gonadotropin hormones is thought to play a role in the pathophysiology of ovarian cancer...
May 21, 2018: Radiation Research
Blake S Porter, Robert Schmidt, David K Bilkey
Effective navigation relies on knowledge of one's environment. A challenge to effective navigation is accounting for the time and energy costs of routes. Irregular terrain in ecological environments poses a difficult navigational problem as organisms ought to avoid effortful slopes to minimize travel costs. Route planning and navigation have previously been shown to involve hippocampal place cells and their ability to encode and store information about an organism's environment. However, little is known about how place cells may encode the slope of space and associated energy costs as experiments are traditionally carried out in flat, horizontal environments...
May 21, 2018: Hippocampus
Karen Krukowski, Xi Feng, Maria Serena Paladini, Austin Chou, Kristen Sacramento, Katherine Grue, Lara-Kirstie Riparip, Tamako Jones, Mary Campbell-Beachler, Gregory Nelson, Susanna Rosi
Microglia are the main immune component in the brain that can regulate neuronal health and synapse function. Exposure to cosmic radiation can cause long-term cognitive impairments in rodent models thereby presenting potential obstacles for astronauts engaged in deep space travel. The mechanism/s for how cosmic radiation induces cognitive deficits are currently unknown. We find that temporary microglia depletion, one week after cosmic radiation, prevents the development of long-term memory deficits. Gene array profiling reveals that acute microglia depletion alters the late neuroinflammatory response to cosmic radiation...
May 18, 2018: Scientific Reports
Mate Szarka, Szabolcs Szilasi, Boglarka Donczo, Daniel Sarkozy, Istvan Rajta, Andras Guttman
On a roundtrip to Mars, astronauts are expectedly exposed to an approximate amount of radiation that exceeds the lifetime limits on Earth. This elevated radiation dose is mainly due to Galactic Cosmic Rays (GCR) and Solar Particle Events (SPE). Specific patterns of the N-glycosylation of human immunoglobulins have already been associated with various ailments such as autoimmune diseases, malignant transformation, chronic inflammation and ageing. The focus of our work was to investigate the effect of low-energy proton irradiation on the IgG N-glycosylation profile with the goal if disease associated changes could be detected during space travel and not altered by space radiation...
May 18, 2018: Electrophoresis
R Gage, N Wilson, L Signal, M Barr, C Mackay, A Reeder, G Thomson
Shade in public spaces can lower the risk of and sun burning and skin cancer. However, existing methods of auditing shade require travel between sites, and sunny weather conditions. This study aimed to evaluate the feasibility of free computer software-Google Earth-for assessing shade in urban open spaces. A shade projection method was developed that uses Google Earth street view and aerial images to estimate shade at solar noon on the summer solstice, irrespective of the date of image capture. Three researchers used the method to separately estimate shade cover over pre-defined activity areas in a sample of 45 New Zealand urban open spaces, including 24 playgrounds, 12 beaches and 9 outdoor pools...
May 16, 2018: Journal of Community Health
Matthew N Julian, David G MacDonnell, Mool C Gupta
A binary phase diffractive optical element photon sieve is fabricated by direct laser ablation of a thin, flexible polyimide substrate with a nanosecond-pulsed ultraviolet laser. The binary phase photon sieve operates at 633 nm and was designed with 19 rings and a focal length of 400 mm. The total time to fabricate the photon sieves was tens of seconds. The surface properties of the laser-processed areas are examined, and the optical performance of the photon sieve is characterized and compared to FDTD simulations...
May 15, 2018: Optics Letters
Yujia Lin, Glory Leung, Dante Louie, Ania Bogoslowski, James Ross, Paul Kubes, Pierre-Yves von der Weid, Shan Liao
Lymphatic vessels remove and transport excess interstitial fluid to lymph nodes (LNs) for fluid balance and immune protection. LNs are typically surrounded by perinodal adipose tissue (PAT). However, PAT is a blood vessel-rich but lymphatic-rare tissue; therefore, how excess fluid in PAT is removed remains unclear. Using C57BL/6 mice, fluorescent dye tracing and transmission electron microscopy results suggest that fluid in PAT can travel to the LN via collagen I+ channels (PAT-LN conduits), merge into a collagen-rich space between the PAT and LN capsule (PAT-LN sinus), and may enter the LN via the LN capsule-associated conduits...
May 14, 2018: Journal of Immunology: Official Journal of the American Association of Immunologists
S A Carvalho, M L Martins
Microorganisms and plants very commonly release toxic secondary chemical compounds (allelochemicals) that inhibit or kill sensitive strains or individuals from their own or other species. In this work we study a model that describes two species interacting through allelopathic suppression and competing for resources. Employing linear stability analysis, the conditions for coexistence or extinction of species in spatially homogeneous systems were determined. We found that the borders between the regimes of bistability, coexistence, and the extinction of the weaker by the stronger competitor, are altered by allelopathic interactions...
April 2018: Physical Review. E
H Esat Kondakci, Ayman F Abouraddy
Although diffractive spreading is an unavoidable feature of all wave phenomena, certain waveforms can attain propagation invariance. A lesser-explored strategy for achieving optical self-similar propagation exploits the modification of the spatiotemporal field structure when observed in reference frames moving at relativistic speeds. For such an observer, it is predicted that the associated Lorentz boost can bring to a halt the axial dynamics of a wave packet of an arbitrary profile. This phenomenon is particularly striking in the case of a self-accelerating beam-such as an Airy beam-whose peak normally undergoes a transverse displacement upon free propagation...
April 20, 2018: Physical Review Letters
Ralph Chapman, Michael Keall, Philippa Howden-Chapman, Mark Grams, Karen Witten, Edward Randal, Alistair Woodward
Active travel (walking and cycling) is beneficial for people’s health and has many co-benefits, such as reducing motor vehicle congestion and pollution in urban areas. There have been few robust evaluations of active travel, and very few studies have valued health and emissions outcomes. The ACTIVE before-and-after quasi-experimental study estimated the net benefits of health and other outcomes from New Zealand’s Model Communities Programme using an empirical analysis comparing two intervention cities with two control cities...
May 11, 2018: International Journal of Environmental Research and Public Health
Brian Iglehart
Laboratory automation improves test reproducibility, which is vital to patient care in clinical laboratories. Many small and specialty laboratories are excluded from the benefits of automation due to low sample number, cost, space, and/or lack of automation expertise. The Minimum Viable Option (MVO) automation platform was developed to address these hurdles and fulfill an unmet need. Consumer 3D printing enabled rapid iterative prototyping to allow for a variety of instrumentation and assay setups and procedures...
May 1, 2018: SLAS Technology
X W Mao, M Boerma, D Rodriguez, M Campbell-Beachler, T Jones, S Stanbouly, V Sridharan, A Wroe, G A Nelson
There is concern that degradation of vision as a result of space flight may compromise both mission goals and long-term quality of life after space travel. The visual disturbances may be due to a combination of intracerebral pressure changes and exposure to ionizing radiation. The retina and the retinal vasculature play important roles in vision, yet have not been studied extensively in relationship to space travel and space radiation. The goal of the current study was to characterize oxidative damage and apoptosis in retinal endothelial cells after whole-body gamma-ray, proton and oxygen (16 O) ion radiation exposure at 0...
May 9, 2018: Radiation Research
Omri Weiss, Anat Levi, Elad Segev, Margarita Simbirsky, David Eilam
In the present study, the dynamic process of group formation in eight unfamiliar rats was followed in order to reveal how the group becomes oriented together in time and space, in light of the complexity that accompanies grouping. The focus was on who, where, and when joined together. We found that rats preferred to be in companionship over remaining alone, with all the rats gradually shifting to share the same location as a resting place. Group formation can be viewed as a tri-phasic process, with some rats gradually becoming more social than others, and thus playing a key role in group formation...
May 2, 2018: Animal Cognition
A Martín Pendás, E Francisco
Real space bonding descriptors are orbital invariant indices that can be obtained independently of the theoretical framework used to compute a given wavefunction. Here we show how to use them to read in real space some widely used concepts in Valence Bond (VB) theory, such as ionic/covalent characters or covalent-ionic resonance energies. All of these are essential ingredients used when building VB chemical insight. Electron number distribution functions are employed to directly map ionic and covalent weights with real space delocalization indices...
May 1, 2018: Physical Chemistry Chemical Physics: PCCP
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