387 research outputs found
Nanoporous biocarbons as a storage system for natural gas as fuel for vehicles
Abstract only availableNatural gas is a promising fuel source because it is safe, inexpensive, cleaner than gasoline, domestically produced, and already has an infrastructure for its distribution. Methane, the main component of natural gas, however, does not have a high energy density, and to store enough in today's natural gas storage tanks to power vehicles, the gas must be compressed to 3600 psi. To be strong enough to hold up at those high pressures, Compressed Natural Gas (CNG) tanks must be bulky and cylindrical, and occupy the trunk space in today's CNG cars, which is considered prohibitive to the cars' market success. ALL-CRAFT's purpose is to develop nanoporous biocarbons which can store methane at relatively low pressures, allowing future tanks to be flat and sleek, ideally occupying the space below the car, making natural gas vehicles attractive consumer products. As a long-term goal, ALL-CRAFT is optimizing biocarbons for hydrogen storage for fuel cells. Nanoporous carbons are like sponges, soaking up molecules of adsorbent gas. The nanoporous biocarbons store up to five times more methane than an empty tank at the same pressure, despite the fact that the carbon obviously takes up space. It does this using van der Waals forces which act on the methane molecules at short distances. These forces cause the methane to form a supercritical fluid film on the surface of the carbon. The extremely high surface area of ALL-CRAFT's carbon samples—recently approaching 4000 square meters of surface per gram of carbon sample—means that our carbons can hold 180 times their volume in methane. Biocarbons can be made from myriad biomass sources. ALL-CRAFT hopes to perfect a process for making them from corn cob; using just the cob is advantageous because this does not displace corn as a food source like Ethanol does.Missouri Academy at Northwest Missouri State University, Alliance for Collaborative Research in Alternate Fuel Technolog
GLUT4 expression and glucose transport in human induced pluripotent stem cell-derived cardiomyocytes
Induced pluripotent stem cell derived cardiomyocytes (iPSC-CM) have the potential to transform regenerative cardiac medicine and the modelling of cardiac disease. This is of particular importance in the context of diabetic cardiomyopathy where diabetic individuals exhibit reduced cardiac diastolic contractile performance in the absence of vascular disease, significantly contributing towards high cardiovascular morbidity. In this study, the capacity of iPSC-CM to act as a novel cellular model of cardiomyocytes was assessed. The diabetic phenotype is characterised by insulin resistance, therefore there was a specific focus upon metabolic parameters. Despite expressing crucial insulin signalling intermediates and relevant trafficking proteins, it was identified that iPSC-CM do not exhibit insulin-stimulated glucose uptake. iPSC-CM are spontaneously contractile however contraction mediated uptake was not found to mask any insulin response. The fundamental limitation identified in these cells was a critical lack of expression of the insulin sensitive glucose transporter GLUT4. Using comparative immunoblot analysis and the GLUT-selective inhibitor BAY-876 to quantify expression of these transporters, we show that iPSC-CM express high levels of GLUT1 and low levels of GLUT4 compared to primary cardiomyocytes and cultured adipocytes. Interventions to overcome this limitation were unsuccessful. We suggest that the utility of iPSC-CMs to study cardiac metabolic disorders may be limited by their apparent foetal-like phenotype
High Resolution X-Ray Micro-CT of Ultra-Thin Wall Space Components
A high resolution micro-CT system has been assembled and is being used to provide optimal characterization for ultra-thin wall space components. The Glenn Research Center NDE Sciences Team, using this CT system, has assumed the role of inspection vendor for the Advanced Stirling Convertor (ASC) project at NASA. This article will discuss many aspects of the development of the CT scanning for this type of component, including CT system overview; inspection requirements; process development, software utilized and developed to visualize, process, and analyze results; calibration sample development; results on actual samples; correlation with optical/SEM characterization; CT modeling; and development of automatic flaw recognition software. Keywords: Nondestructive Evaluation, NDE, Computed Tomography, Imaging, X-ray, Metallic Components, Thin Wall Inspectio
Nurses\u27 Alumnae Association Bulletin, June 1969
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Excitation and decay of projectile-like fragments formed in dissipative peripheral collisions at intermediate energies
Projectile-like fragments (PLF:15<=Z<=46) formed in peripheral and
mid-peripheral collisions of 114Cd projectiles with 92Mo nuclei at E/A=50 MeV
have been detected at very forward angles, 2.1 deg.<=theta_lab<=4.2 deg.
Calorimetric analysis of the charged particles observed in coincidence with the
PLF reveals that the excitation of the primary PLF is strongly related to its
velocity damping. Furthermore, for a given V_PLF*, its excitation is not
related to its size, Z_PLF*. For the largest velocity damping, the excitation
energy attained is large, approximately commensurate with a system at the
limiting temperatureComment: 5 pages, 6 figure
Predicting phase equilibria in polydisperse systems
Many materials containing colloids or polymers are polydisperse: They
comprise particles with properties (such as particle diameter, charge, or
polymer chain length) that depend continuously on one or several parameters.
This review focusses on the theoretical prediction of phase equilibria in
polydisperse systems; the presence of an effectively infinite number of
distinguishable particle species makes this a highly nontrivial task. I first
describe qualitatively some of the novel features of polydisperse phase
behaviour, and outline a theoretical framework within which they can be
explored. Current techniques for predicting polydisperse phase equilibria are
then reviewed. I also discuss applications to some simple model systems
including homopolymers and random copolymers, spherical colloids and
colloid-polymer mixtures, and liquid crystals formed from rod- and plate-like
colloidal particles; the results surveyed give an idea of the rich
phenomenology of polydisperse phase behaviour. Extensions to the study of
polydispersity effects on interfacial behaviour and phase separation kinetics
are outlined briefly.Comment: 48 pages, invited topical review for Journal of Physics: Condensed
Matter; uses Institute of Physics style file iopart.cls (included
Runx1 deficiency protects against adverse cardiac remodeling following myocardial infarction
Background: Myocardial infarction (MI) is a leading cause of heart failure and death worldwide. Preservation of contractile function and protection against adverse changes in ventricular architecture (cardiac remodeling) are key factors to limiting progression of this condition to heart failure. Consequently, new therapeutic targets are urgently required to achieve this aim. Expression of the Runx1 transcription factor is increased in adult cardiomyocytes after MI; however, the functional role of Runx1 in the heart is unknown.
Methods: To address this question, we have generated a novel tamoxifen-inducible cardiomyocyte-specific Runx1-deficient mouse. Mice were subjected to MI by means of coronary artery ligation. Cardiac remodeling and contractile function were assessed extensively at the whole-heart, cardiomyocyte, and molecular levels.
Results: Runx1-deficient mice were protected against adverse cardiac remodeling after MI, maintaining ventricular wall thickness and contractile function. Furthermore, these mice lacked eccentric hypertrophy, and their cardiomyocytes exhibited markedly improved calcium handling. At the mechanistic level, these effects were achieved through increased phosphorylation of phospholamban by protein kinase A and relief of sarco/endoplasmic reticulum Ca2+-ATPase inhibition. Enhanced sarco/endoplasmic reticulum Ca2+-ATPase activity in Runx1-deficient mice increased sarcoplasmic reticulum calcium content and sarcoplasmic reticulum–mediated calcium release, preserving cardiomyocyte contraction after MI.
Conclusions: Our data identified Runx1 as a novel therapeutic target with translational potential to counteract the effects of adverse cardiac remodeling, thereby improving survival and quality of life among patients with MI
Spatially Explicit Network Analysis Reveals Multi‐Species Annual Cycle Movement Patterns of Sea Ducks
Conservation of long‐distance migratory species poses unique challenges. Migratory connectivity, that is, the extent to which groupings of individuals at breeding sites are maintained in wintering areas, is frequently used to evaluate population structure and assess use of key habitat areas. However, for species with complex or variable annual cycle movements, this traditional bimodal framework of migratory connectivity may be overly simplistic. Like many other waterfowl, sea ducks often travel to specific pre‐ and post‐breeding sites outside their nesting and wintering areas to prepare for migration by feeding extensively and, in some cases, molting their flight feathers. These additional migrations may play a key role in population structure, but are not included in traditional models of migratory connectivity. Network analysis, which applies graph theory to assess linkages between discrete locations or entities, offers a powerful tool for quantitatively assessing the contributions of different sites used throughout the annual cycle to complex spatial networks. We collected satellite telemetry data on annual cycle movements of 672 individual sea ducks of five species from throughout eastern North America and the Great Lakes. From these data, we constructed a multi‐species network model of migratory patterns and site use over the course of breeding, molting, wintering, and migratory staging. Our results highlight inter‐ and intra‐specific differences in the patterns and complexity of annual cycle movement patterns, including the central importance of staging and molting sites in James Bay, the St. Lawrence River, and southern New England to multi‐species annual cycle habitat linkages, and highlight the value of Long‐tailed Ducks (Calengula haemalis) as an umbrella species to represent the movement patterns of multiple sea duck species. We also discuss potential applications of network migration models to conservation prioritization, identification of population units, and integrating different data streams
Implanted Satellite Transmitters Affect Sea Duck Movement Patterns at Short and Long Timescales
Studies of the effects of transmitters on wildlife often focus on survival. However, sublethal behavioral changes resulting from radio-marking have the potential to affect inferences from telemetry data and may vary based on individual and environmental characteristics. We used a long-term, multi-species tracking study of sea ducks to assess behavioral patterns at multiple temporal scales following implantation of intracoelomic satellite transmitters. We applied state-space models to assess short-term behavioral patterns in 476 individuals with implanted satellite transmitters, as well as comparing breeding site attendance and migratory phenology across multiple years after capture. In the short term, our results suggest an increase in dispersive behavior immediately following capture and transmitter implantation; however, behavior returned to seasonally average patterns within ~5 days after release. Over multiple years, we found that breeding site attendance by both males and females was depressed during the first breeding season after radio-marking relative to subsequent years, with larger relative decreases in breeding site attendance among males than females. We also found that spring and breeding migrations occurred later in the first year after radio-marking than in subsequent years. Across all behavioral effects, the severity of behavioral change often varied by species, sex, age, and capture season. We conclude that, although individuals appear to adjust relatively quickly (i.e. within 1 week) to implanted satellite transmitters, changes in breeding phenology may occur over the longer term and should be considered when analyzing and reporting telemetry data
Marketing Actions and the Value of Customer Assets: A Framework for Customer Asset Management
This article develops a framework for assessing how marketing actions affect customers’lifetime value to the firm. The framework is organized around four critical actions that firms must take to effectively manage the asset value of the customer base: database creation, market segmentation, forecasting customer purchase behavior, and resource allocation. In this framework, customer lifetime value is treated as a dynamic construct, that is, it influences the eventual allocation of marketing resources but is also influenced by that allocation. By viewing customers as assets and systematically managing these assets, a firm can identify the most appropriate marketing actions to acquire, maintain, and enhance customer assets and thereby maximize financial returns. The article discusses in detail how to assess customer lifetime value and manage customers as assets. Then, it identifies key research challenges in studying customer asset management and the managerial challenges associated with implementing effective customer asset management practices.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline
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