Sample records for coherent interface sci
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The Simulation of Read-time Scalable Coherent Interface
NASA Technical Reports Server (NTRS)
Li, Qiang; Grant, Terry; Grover, Radhika S.
1997-01-01
Scalable Coherent Interface (SCI, IEEE/ANSI Std 1596-1992) (SCI1, SCI2) is a high performance interconnect for shared memory multiprocessor systems. In this project we investigate an SCI Real Time Protocols (RTSCI1) using Directed Flow Control Symbols. We studied the issues of efficient generation of control symbols, and created a simulation model of the protocol on a ring-based SCI system. This report presents the results of the study. The project has been implemented using SES/Workbench. The details that follow encompass aspects of both SCI and Flow Control Protocols, as well as the effect of realistic client/server processing delay. The report is organized as follows. Section 2 provides a description of the simulation model. Section 3 describes the protocol implementation details. The next three sections of the report elaborate on the workload, results and conclusions. Appended to the report is a description of the tool, SES/Workbench, used in our simulation, and internal details of our implementation of the protocol.
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Dominici, Nadia; Keller, Urs; Vallery, Heike; Friedli, Lucia; van den Brand, Rubia; Starkey, Michelle L; Musienko, Pavel; Riener, Robert; Courtine, Grégoire
2012-07-01
Central nervous system (CNS) disorders distinctly impair locomotor pattern generation and balance, but technical limitations prevent independent assessment and rehabilitation of these subfunctions. Here we introduce a versatile robotic interface to evaluate, enable and train pattern generation and balance independently during natural walking behaviors in rats. In evaluation mode, the robotic interface affords detailed assessments of pattern generation and dynamic equilibrium after spinal cord injury (SCI) and stroke. In enabling mode,the robot acts as a propulsive or postural neuroprosthesis that instantly promotes unexpected locomotor capacities including overground walking after complete SCI, stair climbing following partial SCI and precise paw placement shortly after stroke. In training mode, robot-enabled rehabilitation, epidural electrical stimulation and monoamine agonists reestablish weight-supported locomotion, coordinated steering and balance in rats with a paralyzing SCI. This new robotic technology and associated concepts have broad implications for both assessing and restoring motor functions after CNS disorders, both in animals and in humans.
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1983-09-08
1982). 4. A. Hiraki , M.-A. Nicolet, and J.W. Mayer, Appl. Phys. Lett. 18, 178 (1971); A. Hiraki , K. Shuto, S. Kim, W. Kammura, and M. twami, ibid 31...Vac. Sci. Technol. 17, 930 (1980) and references therein. 13 T. Narusera, K. Kinoehica, W. 1. Gibson, and A. Hiraki , J. Vac. Sci. Technol. L$, 272
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Relaxation, Structure and Properties of Semi-coherent Interfaces
Shao, Shuai; Wang, Jian
2015-11-05
Materials containing high density of interfaces are promising candidates for future energy technologies, because interfaces acting as sources, sinks, and barriers for defects can improve mechanical and irradiation properties of materials. Semi-coherent interface widely occurring in various materials is composed of a network of misfit dislocations and coherent regions separated by misfit dislocations. Lastly, in this article, we review relaxation mechanisms, structure and properties of (111) semi-coherent interfaces in face centered cubic structures.
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Electronic structure and relative stability of the coherent and semi-coherent HfO2/III-V interfaces
NASA Astrophysics Data System (ADS)
Lahti, A.; Levämäki, H.; Mäkelä, J.; Tuominen, M.; Yasir, M.; Dahl, J.; Kuzmin, M.; Laukkanen, P.; Kokko, K.; Punkkinen, M. P. J.
2018-01-01
III-V semiconductors are prominent alternatives to silicon in metal oxide semiconductor devices. Hafnium dioxide (HfO2) is a promising oxide with a high dielectric constant to replace silicon dioxide (SiO2). The potentiality of the oxide/III-V semiconductor interfaces is diminished due to high density of defects leading to the Fermi level pinning. The character of the harmful defects has been intensively debated. It is very important to understand thermodynamics and atomic structures of the interfaces to interpret experiments and design methods to reduce the defect density. Various realistic gap defect state free models for the HfO2/III-V(100) interfaces are presented. Relative energies of several coherent and semi-coherent oxide/III-V semiconductor interfaces are determined for the first time. The coherent and semi-coherent interfaces represent the main interface types, based on the Ga-O bridges and As (P) dimers, respectively.
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Revisiting the Al/Al₂O₃ interface: coherent interfaces and misfit accommodation.
Pilania, Ghanshyam; Thijsse, Barend J; Hoagland, Richard G; Lazić, Ivan; Valone, Steven M; Liu, Xiang-Yang
2014-03-27
We study the coherent and semi-coherent Al/α-Al2O3 interfaces using molecular dynamics simulations with a mixed, metallic-ionic atomistic model. For the coherent interfaces, both Al-terminated and O-terminated nonstoichiometric interfaces have been studied and their relative stability has been established. To understand the misfit accommodation at the semi-coherent interface, a 1-dimensional (1D) misfit dislocation model and a 2-dimensional (2D) dislocation network model have been studied. For the latter case, our analysis reveals an interface dislocation structure with a network of three sets of parallel dislocations, each with pure-edge character, giving rise to a pattern of coherent and stacking-fault-like regions at the interface. Structural relaxation at elevated temperatures leads to a further change of the dislocation pattern, which can be understood in terms of a competition between the stacking fault energy and the dislocation interaction energy at the interface. Our results are expected to serve as an input for the subsequent dislocation dynamics models to understand and predict the macroscopic mechanical behavior of Al/α-Al2O3 composite heterostructures.
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Revisiting the Al/Al 2O 3 Interface: Coherent Interfaces and Misfit Accommodation
DOE Office of Scientific and Technical Information (OSTI.GOV)
Pilania, Ghanshyam; Thijsse, Barend J.; Hoagland, Richard G.
We report the coherent and semi-coherent Al/α-Al 2O 3 interfaces using molecular dynamics simulations with a mixed, metallic-ionic atomistic model. For the coherent interfaces, both Al-terminated and O-terminated nonstoichiometric interfaces have been studied and their relative stability has been established. To understand the misfit accommodation at the semi-coherent interface, a 1-dimensional (1D) misfit dislocation model and a 2-dimensional (2D) dislocation network model have been studied. For the latter case, our analysis reveals an interface dislocation structure with a network of three sets of parallel dislocations, each with pure-edge character, giving rise to a pattern of coherent and stacking-fault-like regions atmore » the interface. Structural relaxation at elevated temperatures leads to a further change of the dislocation pattern, which can be understood in terms of a competition between the stacking fault energy and the dislocation interaction energy at the interface. In conclusion, our results are expected to serve as an input for the subsequent dislocation dynamics models to understand and predict the macroscopic mechanical behavior of Al/α-Al 2O 3 composite heterostructures.« less
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Revisiting the Al/Al 2O 3 Interface: Coherent Interfaces and Misfit Accommodation
Pilania, Ghanshyam; Thijsse, Barend J.; Hoagland, Richard G.; ...
2014-03-27
We report the coherent and semi-coherent Al/α-Al 2O 3 interfaces using molecular dynamics simulations with a mixed, metallic-ionic atomistic model. For the coherent interfaces, both Al-terminated and O-terminated nonstoichiometric interfaces have been studied and their relative stability has been established. To understand the misfit accommodation at the semi-coherent interface, a 1-dimensional (1D) misfit dislocation model and a 2-dimensional (2D) dislocation network model have been studied. For the latter case, our analysis reveals an interface dislocation structure with a network of three sets of parallel dislocations, each with pure-edge character, giving rise to a pattern of coherent and stacking-fault-like regions atmore » the interface. Structural relaxation at elevated temperatures leads to a further change of the dislocation pattern, which can be understood in terms of a competition between the stacking fault energy and the dislocation interaction energy at the interface. In conclusion, our results are expected to serve as an input for the subsequent dislocation dynamics models to understand and predict the macroscopic mechanical behavior of Al/α-Al 2O 3 composite heterostructures.« less
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ScienceDirect through SciVerse: a new way to approach Elsevier.
Bengtson, Jason
2011-01-01
SciVerse is the new combined portal from Elsevier that services their ScienceDirect collection, SciTopics, and their Scopus database. Using SciVerse to access ScienceDirect is the specific focus of this review. Along with advanced keyword searching and citation searching options, SciVerse also incorporates a very useful image search feature. The aim seems to be not only to create an interface that provides broad functionality on par with other database search tools that many searchers use regularly but also to create an open platform that could be changed to respond effectively to the needs of customers.
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2011-01-01
364 (1996). 10. B. Jeong, Y. H. Bae, D. S. Lee, and S. W. Kim, Biodegradable block copolymers as injectable drug-delivery systems . Nature 388, 860-862...1250-1253 (1995). 26. F. C. MacKintosh, and C. F. Schmidt, Microrheology, Curr. Opin. Colloid Interface Sci. 4, 300-307 (1999). 27. A...Mukhopadhyay, and S. Granick, Micro- and nanorheology, Curr. Opin. Colloid Interface Sci. 6, 423-429 (2001). 28. Y. Li, and T. Tanaka, Kinetics of swelling
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Shahdoost, Shahab; Frost, Shawn; Van Acker, Gustaf; DeJong, Stacey; Dunham, Caleb; Barbay, Scott; Nudo, Randolph; Mohseni, Pedram
2014-01-01
Nearly 6 million people in the United States are currently living with paralysis in which 23% of the cases are related to spinal cord injury (SCI). Miniaturized closed-loop neural interfaces have the potential for restoring function and mobility lost to debilitating neural injuries such as SCI by leveraging recent advancements in bioelectronics and a better understanding of the processes that underlie functional and anatomical reorganization in an injured nervous system. This paper describes our current progress towards developing a miniaturized brain-machine-spinal cord interface (BMSI) that is envisioned to convert in real time the neural command signals recorded from the brain to electrical stimuli delivered to the spinal cord below the injury level. Specifically, the paper reports on a corticospinal interface integrated circuit (IC) as a core building block for such a BMSI that is capable of low-noise recording of extracellular neural spikes from the cerebral cortex as well as muscle activation using intraspinal microstimulation (ISMS) in a rat with contusion injury to the thoracic spinal cord. The paper further presents results from a neurobiological study conducted in both normal and SCI rats to investigate the effect of various ISMS parameters on movement thresholds in the rat hindlimb. Coupled with proper signal-processing algorithms in the future for the transformation between the cortically recorded data and ISMS parameters, such a BMSI has the potential to facilitate functional recovery after an SCI by re-establishing corticospinal communication channels lost due to the injury.
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Coherent Electron Transfer at the Ag / Graphite Heterojunction Interface
NASA Astrophysics Data System (ADS)
Tan, Shijing; Dai, Yanan; Zhang, Shengmin; Liu, Liming; Zhao, Jin; Petek, Hrvoje
2018-03-01
Charge transfer in transduction of light to electrical or chemical energy at heterojunctions of metals with semiconductors or semimetals is believed to occur by photogenerated hot electrons in metal undergoing incoherent internal photoemission through the heterojunction interface. Charge transfer, however, can also occur coherently by dipole coupling of electronic bands at the heterojunction interface. Microscopic physical insights into how transfer occurs can be elucidated by following the coherent polarization of the donor and acceptor states on the time scale of electronic dephasing. By time-resolved multiphoton photoemission spectroscopy (MPP), we investigate the coherent electron transfer from an interface state that forms upon chemisorption of Ag nanoclusters onto graphite to a σ symmetry interlayer band of graphite. Multidimensional MPP spectroscopy reveals a resonant two-photon transition, which dephases within 10 fs completing the coherent transfer.
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A Review and Evaluation of Integrated Atmospheric Boundary-Layer Models for Maritime Applications.
1981-11-01
Released by: WILLIAM M. TOLLES Dean of Research UNCLASSIFIED SECURITY CLASSIFICAION OF THIS1 PAGE (Whim DO& 801090 I" READ UES7RUCTIONSREPORT... Stull , R.B., 1976: "The energetics of entrainment across a density interface", J. Atmos. Sci., 33, 1260-1267. 5. Stage, S.A. and J.A. Businger, 1981: "A...Vol. 36, pp. 424-436. 1979. 17. Stull , Roland B., "The Energetics of Entrainment Across a Density Interface," J. AtUos. Sci., Vol. 33, pp. 1260-1267
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pH-dependent surface charging and points of zero charge. IV. Update and new approach.
Kosmulski, Marek
2009-09-15
The recently published points of zero charge (PZC) and isoelectric points (IEPs) of various materials are compiled to update the previous compilation [M. Kosmulski, Surface Charging and Points of Zero Charge, CRC Press, Boca Raton, FL, 2009]. Unlike in previous compilations by the same author [Chemical Properties of Material Surfaces, Dekker, New York, 2001; J. Colloid Interface Sci. 253 (2002) 77; J. Colloid Interface Sci. 275 (2004) 214; J. Colloid Interface Sci. 298 (2006) 730], the materials are sorted not only by the chemical formula, but also by specific product, that is, by brand name (commercially available materials), and by recipe (home-synthesized materials). This new approach indicated that the relatively consistent PZC/IEP reported in the literature for materials having the same chemical formula are due to biased choice of specimens to be studied. Specimens which have PZC/IEP close to the "recommended" value are selected more often than other specimens (PZC/IEP not reported before or PZC/IEP reported, but different from the "recommended" value). Thus, the previously published PZC/IEP act as a self-fulfilling prophecy.
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NASA Astrophysics Data System (ADS)
Dingreville, Rémi; Hallil, Abdelmalek; Berbenni, Stéphane
2014-12-01
The equilibrium of coherent and incoherent mismatched interfaces is reformulated in the context of continuum mechanics based on the Gibbs dividing surface concept. Two surface stresses are introduced: a coherent surface stress and an incoherent surface stress, as well as a transverse excess strain. The coherent surface stress and the transverse excess strain represent the thermodynamic driving forces of stretching the interface while the incoherent surface stress represents the driving force of stretching one crystal while holding the other fixed and thereby altering the structure of the interface. These three quantities fully characterize the elastic behavior of coherent and incoherent interfaces as a function of the in-plane strain, the transverse stress and the mismatch strain. The isotropic case is developed in detail and particular attention is paid to the case of interfacial thermo-elasticity. This exercise provides an insight on the physical significance of the interfacial elastic constants introduced in the formulation and illustrates the obvious coupling between the interface structure and its associated thermodynamics quantities. Finally, an example based on atomistic simulations of Cu/Cu2O interfaces is given to demonstrate the relevance of the generalized interfacial formulation and to emphasize the dependence of the interfacial thermodynamic quantities on the incoherency strain with an actual material system.
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Dingreville, Rémi; Hallil, Abdelmalek; Berbenni, Stéphane
2014-08-19
The equilibrium of coherent and incoherent mismatched interfaces is reformulated in the context of continuum mechanics based on the Gibbs dividing surface concept. Two surface stresses are introduced: a coherent surface stress and an incoherent surface stress, as well as a transverse excess strain. Additionally, the coherent surface stress and the transverse excess strain represent the thermodynamic driving forces of stretching the interface while the incoherent surface stress represents the driving force of stretching one crystal while holding the other fixed and thereby altering the structure of the interface. These three quantities fully characterize the elastic behavior of coherent andmore » incoherent interfaces as a function of the in-plane strain, the transverse stress and the mismatch strain. The isotropic case is developed in detail and particular attention is paid to the case of interfacial thermo-elasticity. This exercise provides an insight on the physical significance of the interfacial elastic constants introduced in the formulation and illustrates the obvious coupling between the interface structure and its associated thermodynamics quantities. Finally, an example based on atomistic simulations of Cu/Cu 2O interfaces is given to demonstrate the relevance of the generalized interfacial formulation and to emphasize the dependence of the interfacial thermodynamic quantities on the incoherency strain with an actual material system.« less
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Operation of a P300-based brain-computer interface by individuals with cervical spinal cord injury.
Ikegami, Shiro; Takano, Kouji; Saeki, Naokatsu; Kansaku, Kenji
2011-05-01
This study evaluates the efficacy of a P300-based brain-computer interface (BCI) with green/blue flicker matrices for individuals with cervical spinal cord injury (SCI). Ten individuals with cervical SCI (age 26-53, all male) and 10 age- and sex-matched able-bodied controls (age 27-52, all male) with no prior BCI experience were asked to input hiragana (Japanese alphabet) characters using the P300 BCI with two distinct types of visual stimuli, white/gray and green/blue, in an 8×10 flicker matrix. Both online and offline performance were evaluated. The mean online accuracy of the SCI subjects was 88.0% for the white/gray and 90.7% for the green/blue flicker matrices. The accuracy of the control subjects was 77.3% and 86.0% for the white/gray and green/blue, respectively. There was a significant difference in online accuracy between the two types of flicker matrix. SCI subjects performed with greater accuracy than controls, but the main effect was not significant. Individuals with cervical SCI successfully controlled the P300 BCI, and the green/blue flicker matrices were associated with significantly higher accuracy than the white/gray matrices. The P300 BCI with the green/blue flicker matrices is effective for use not only in able-bodied subjects, but also in individuals with cervical SCI. Copyright © 2010 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.
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NASA Astrophysics Data System (ADS)
Xu, Zhenfeng; Ding, Zhimin; Liang, Bo
2018-03-01
The M23C6 carbides precipitate along the austenite grain boundary in the 100Mn13 high carbon high manganese steel after 1323 K (1050 °C) solution treatment and subsequent 748 K (475 °C) aging treatment. The grain boundary M23C6 carbides not only spread along the grain boundary and into the incoherent austenite grain, but also grow slowly into the coherent austenite grain. On the basis of the research with optical microscope, a further investigation for the M23C6/ γ coherent interface was carried out by transmission electron microscope (TEM). The results show that the grain boundary M23C6 carbides have orientation relationships with only one of the adjacent austenite grains in the same planes: (\\bar{1}1\\bar{1})_{{{M}_{ 2 3} {C}_{ 6} }} //(\\bar{1}1\\bar{1})_{γ } , (\\bar{1}11)_{{{M}_{ 2 3} {C}_{ 6} }} //(\\bar{1}11)_{γ } ,[ 1 10]_{{{M}_{ 2 3} {C}_{ 6} }} //[ 1 10]_{γ } . The flat M23C6/ γ coherent interface lies on the low indexed crystal planes {111}. Moreover, in M23C6/ γ coherent interface, there are embossments which stretch into the coherent austenite grain γ. Dislocations distribute in the embossments and coherent interface frontier. According to the experimental observation, the paper suggests that the embossments can promote the M23C6/ γ coherent interface move. Besides, the present work has analyzed chemical composition of experimental material and the crystal structures of austenite and M23C6, which indicates that the transformation can be completed through a little diffusion for C atoms and a simple variant for austenite unit cell.
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Tough, Hannah; Fekete, Christine; Brinkhof, Martin W G; Siegrist, Johannes
2017-04-01
Various social relationship constructs have been proposed to affect mental health. However, these constructs have rarely been studied in a comprehensive way in persons with chronic disabilities and their partners, inhibiting researchers from evaluating their relative importance. To investigate 1) the variation in the quantity and quality of social relationships in persons with spinal cord injury (SCI) and their partners; 2) dyadic coherence within social relationship constructs; 3) the interrelationships between social relationship constructs; and 4) the associations of social relationship constructs with vitality and mental health. Cross-sectional survey data from 133 couples of persons with SCI and their partners was used. Quantitative (social networks) and qualitative aspects (social support, relationship quality, loneliness, and reciprocity in partnerships) of social relationships were assessed. Correlations were performed to analyse dyadic coherence and interrelationships of social relationship constructs and multivariable regressions were applied to examine associations with vitality and mental health. Loneliness, larger social networks and higher relationship quality were more prevalent in SCI. All social relationship constructs, apart from loneliness, were more similar within couples than between couples and the interrelationships between different constructs were small. Qualitative aspects of relationships were more important than the quantitative aspects in their associations to vitality and mental health. These associations were most consistent for loneliness, reciprocity and relationship quality in both groups. In the long-term management of community functioning in persons with SCI and their partners, the fostering of high quality intimate relationships should take priority. Copyright © 2016 Elsevier Inc. All rights reserved.
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NASA Astrophysics Data System (ADS)
Srivastava, Amar; Herng, T. S.; Saha, Surajit; Nina, Bao; Annadi, A.; Naomi, N.; Liu, Z. Q.; Dhar, S.; Ariando; Ding, J.; Venkatesan, T.
2012-06-01
We have investigated the photoluminescence and electrical properties of a coherently coupled interface consisting of a ZnO layer grown on top of an oriented VO2 layer on sapphire across the phase transition of VO2. The band edge and defect luminescence of the ZnO overlayer exhibit hysteresis in opposite directions induced by the phase transition of VO2. Concomitantly the phase transition of VO2 was seen to induce defects in the ZnO layer. Such coherently coupled interfaces could be of use in characterizing the stability of a variety of interfaces in situ and also for novel device application.
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Final Report for DOE Project: Portal Web Services: Support of DOE SciDAC Collaboratories
DOE Office of Scientific and Technical Information (OSTI.GOV)
Mary Thomas, PI; Geoffrey Fox, Co-PI; Gannon, D
2007-10-01
Grid portals provide the scientific community with familiar and simplified interfaces to the Grid and Grid services, and it is important to deploy grid portals onto the SciDAC grids and collaboratories. The goal of this project is the research, development and deployment of interoperable portal and web services that can be used on SciDAC National Collaboratory grids. This project has four primary task areas: development of portal systems; management of data collections; DOE science application integration; and development of web and grid services in support of the above activities.
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Interface-induced localization in AlSb/InAs heterostructures
NASA Astrophysics Data System (ADS)
Shaw, M. J.; Briddon, P. R.; Jaros, M.
1995-12-01
The existence of localized states at perfect InSb-like interfaces in AlSb/InAs superlattices is predicted from ab initio pseudopotential calculations. Localized states are predicted in both the valence and conduction bands, the former being identifiable with the interface states proposed by Kroemer, Nguyen, and Brar [J. Vac. Sci. Technol. 10, 1769 (1990)]. The existence of these interface localized states is invoked to explain the reported experimental dependence of the band gap upon interface types in such superlattices.
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Relaxation mechanisms, structure and properties of semi-coherent interfaces
Shao, Shuai; Wang, Jian
2015-10-15
In this work, using the Cu–Ni (111) semi-coherent interface as a model system, we combine atomistic simulations and defect theory to reveal the relaxation mechanisms, structure, and properties of semi-coherent interfaces. By calculating the generalized stacking fault energy (GSFE) profile of the interface, two stable structures and a high-energy structure are located. During the relaxation, the regions that possess the stable structures expand and develop into coherent regions; the regions with high-energy structure shrink into the intersection of misfit dislocations (nodes). This process reduces the interface excess potential energy but increases the core energy of the misfit dislocations and nodes.more » The core width is dependent on the GSFE of the interface. The high-energy structure relaxes by relative rotation and dilatation between the crystals. The relative rotation is responsible for the spiral pattern at nodes. The relative dilatation is responsible for the creation of free volume at nodes, which facilitates the nodes’ structural transformation. Several node structures have been observed and analyzed. In conclusion, the various structures have significant impact on the plastic deformation in terms of lattice dislocation nucleation, as well as the point defect formation energies.« less
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Coherent Light at the Interface Between Two Media
NASA Astrophysics Data System (ADS)
Kundikova, N. D.
2016-02-01
Reflection and refraction of coherent polarized radiation at the interface between two media are considered. It is shown that deviations from the well-known laws of geometrical optics are possible under certain conditions. The causes of such a deviation are considered.
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www.elearnSCI.org: a global educational initiative of ISCoS.
Chhabra, H S; Harvey, L A; Muldoon, S; Chaudhary, S; Arora, M; Brown, D J; Biering-Sorensen, F; Wyndaele, J J; Charlifue, S; Horsewell, J; Ducharme, S; Green, D; Simpson, D; Glinsky, J; Weerts, E; Upadhyay, N; Aito, S; Wing, P; Katoh, S; Kovindha, A; Krassioukov, A; Weeks, C; Srikumar, V; Reeves, R; Siriwardane, C; Hasnan, N; Kalke, Y B; Lanig, I
2013-03-01
To develop a web-based educational resource for health professionals responsible for the management of spinal cord injury (SCI). The resource:www.elearnSCI.org is comprised of seven learning modules, each subdivided into various submodules. Six of the seven modules address the educational needs of all disciplines involved in comprehensive SCI management. The seventh module addresses prevention of SCI. Each submodule includes an overview, activities, self-assessment questions and references. Three hundred and thirty-two experts from The International Spinal Cord Society (ISCoS) and various affiliated societies from 36 countries were involved in developing the resource through 28 subcommittees. The content of each submodule was reviewed and approved by the Education and Scientific Committees of ISCoS and finally by an Editorial Committee of 23 experts. The content of the learning modules is relevant to students and to new as well as experienced SCI healthcare professionals. The content is applicable globally, has received consumer input and is available at no cost. The material is presented on a website underpinned by a sophisticated content-management system, which allows easy maintenance and ready update of all the content. The resource conforms to key principles of e-learning, including appropriateness of curriculum, engagement of learners, innovative approaches, effective learning, ease of use, inclusion, assessment, coherence, consistency, transparency, cost effectiveness and feedback. www.elearnSCI.org provides a cost effective way of training healthcare professionals that goes beyond the textbook and traditional face-to-face teaching.
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The growth mechanism of grain boundary carbide in Alloy 690
DOE Office of Scientific and Technical Information (OSTI.GOV)
Li, Hui, E-mail: huili@shu.edu.cn; Institute of Materials, Shanghai University, Shanghai 200072; Xia, Shuang
2013-07-15
The growth mechanism of grain boundary M{sub 23}C{sub 6} carbides in nickel base Alloy 690 after aging at 715 °C was investigated by high resolution transmission electron microscopy. The grain boundary carbides have coherent orientation relationship with only one side of the matrix. The incoherent phase interface between M{sub 23}C{sub 6} and matrix was curved, and did not lie on any specific crystal plane. The M{sub 23}C{sub 6} carbide transforms from the matrix phase directly at the incoherent interface. The flat coherent phase interface generally lies on low index crystal planes, such as (011) and (111) planes. The M{sub 23}C{submore » 6} carbide transforms from a transition phase found at curved coherent phase interface. The transition phase has a complex hexagonal crystal structure, and has coherent orientation relationship with matrix and M{sub 23}C{sub 6}: (111){sub matrix}//(0001){sub transition}//(111){sub carbide}, <112{sup ¯}>{sub matrix}//<21{sup ¯}10>{sub transition}//<112{sup ¯}>{sub carbide}. The crystal lattice constants of transition phase are c{sub transition}=√(3)×a{sub matrix} and a{sub transition}=√(6)/2×a{sub matrix}. Based on the experimental results, the growth mechanism of M{sub 23}C{sub 6} and the formation mechanism of transition phase are discussed. - Highlights: • A transition phase was observed at the coherent interfaces of M{sub 23}C{sub 6} and matrix. • The transition phase has hexagonal structure, and is coherent with matrix and M{sub 23}C{sub 6}. • The M{sub 23}C{sub 6} transforms from the matrix directly at the incoherent phase interface.« less
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NASA Astrophysics Data System (ADS)
Appel, Marius; Lahn, Florian; Pebesma, Edzer; Buytaert, Wouter; Moulds, Simon
2016-04-01
Today's amount of freely available data requires scientists to spend large parts of their work on data management. This is especially true in environmental sciences when working with large remote sensing datasets, such as obtained from earth-observation satellites like the Sentinel fleet. Many frameworks like SpatialHadoop or Apache Spark address the scalability but target programmers rather than data analysts, and are not dedicated to imagery or array data. In this work, we use the open-source data management and analytics system SciDB to bring large earth-observation datasets closer to analysts. Its underlying data representation as multidimensional arrays fits naturally to earth-observation datasets, distributes storage and computational load over multiple instances by multidimensional chunking, and also enables efficient time-series based analyses, which is usually difficult using file- or tile-based approaches. Existing interfaces to R and Python furthermore allow for scalable analytics with relatively little learning effort. However, interfacing SciDB and file-based earth-observation datasets that come as tiled temporal snapshots requires a lot of manual bookkeeping during ingestion, and SciDB natively only supports loading data from CSV-like and custom binary formatted files, which currently limits its practical use in earth-observation analytics. To make it easier to work with large multi-temporal datasets in SciDB, we developed software tools that enrich SciDB with earth observation metadata and allow working with commonly used file formats: (i) the SciDB extension library scidb4geo simplifies working with spatiotemporal arrays by adding relevant metadata to the database and (ii) the Geospatial Data Abstraction Library (GDAL) driver implementation scidb4gdal allows to ingest and export remote sensing imagery from and to a large number of file formats. Using added metadata on temporal resolution and coverage, the GDAL driver supports time-based ingestion of imagery to existing multi-temporal SciDB arrays. While our SciDB plugin works directly in the database, the GDAL driver has been specifically developed using a minimum amount of external dependencies (i.e. CURL). Source code for both tools is available from github [1]. We present these tools in a case-study that demonstrates the ingestion of multi-temporal tiled earth-observation data to SciDB, followed by a time-series analysis using R and SciDBR. Through the exclusive use of open-source software, our approach supports reproducibility in scalable large-scale earth-observation analytics. In the future, these tools can be used in an automated way to let scientists only work on ready-to-use SciDB arrays to significantly reduce the data management workload for domain scientists. [1] https://github.com/mappl/scidb4geo} and \\url{https://github.com/mappl/scidb4gdal
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Measurement of Coherent π^{+} Production in Low Energy Neutrino-Carbon Scattering.
Abe, K; Andreopoulos, C; Antonova, M; Aoki, S; Ariga, A; Assylbekov, S; Autiero, D; Ban, S; Barbi, M; Barker, G J; Barr, G; Bartet-Friburg, P; Batkiewicz, M; Bay, F; Berardi, V; Berkman, S; Bhadra, S; Blondel, A; Bolognesi, S; Bordoni, S; Boyd, S B; Brailsford, D; Bravar, A; Bronner, C; Buizza Avanzini, M; Calland, R G; Campbell, T; Cao, S; Caravaca Rodríguez, J; Cartwright, S L; Castillo, R; Catanesi, M G; Cervera, A; Cherdack, D; Chikuma, N; Christodoulou, G; Clifton, A; Coleman, J; Collazuol, G; Coplowe, D; Cremonesi, L; Dabrowska, A; De Rosa, G; Dealtry, T; Denner, P F; Dennis, S R; Densham, C; Dewhurst, D; Di Lodovico, F; Di Luise, S; Dolan, S; Drapier, O; Duffy, K E; Dumarchez, J; Dytman, S; Dziewiecki, M; Emery-Schrenk, S; Ereditato, A; Feusels, T; Finch, A J; Fiorentini, G A; Friend, M; Fujii, Y; Fukuda, D; Fukuda, Y; Furmanski, A P; Galymov, V; Garcia, A; Giffin, S G; Giganti, C; Gizzarelli, F; Gonin, M; Grant, N; Hadley, D R; Haegel, L; Haigh, M D; Hamilton, P; Hansen, D; Harada, J; Hara, T; Hartz, M; Hasegawa, T; Hastings, N C; Hayashino, T; Hayato, Y; Helmer, R L; Hierholzer, M; Hillairet, A; Himmel, A; Hiraki, T; Hirota, S; Hogan, M; Holeczek, J; Horikawa, S; Hosomi, F; Huang, K; Ichikawa, A K; Ieki, K; Ikeda, M; Imber, J; Insler, J; Intonti, R A; Irvine, T J; Ishida, T; Ishii, T; Iwai, E; Iwamoto, K; Izmaylov, A; Jacob, A; Jamieson, B; Jiang, M; Johnson, S; Jo, J H; Jonsson, P; Jung, C K; Kabirnezhad, M; Kaboth, A C; Kajita, T; Kakuno, H; Kameda, J; Karlen, D; Karpikov, I; Katori, T; Kearns, E; Khabibullin, M; Khotjantsev, A; Kielczewska, D; Kikawa, T; Kim, H; Kim, J; King, S; Kisiel, J; Knight, A; Knox, A; Kobayashi, T; Koch, L; Koga, T; Konaka, A; Kondo, K; Kopylov, A; Kormos, L L; Korzenev, A; Koshio, Y; Kropp, W; Kudenko, Y; Kurjata, R; Kutter, T; Lagoda, J; Lamont, I; Larkin, E; Lasorak, P; Laveder, M; Lawe, M; Lazos, M; Lindner, T; Liptak, Z J; Litchfield, R P; Li, X; Longhin, A; Lopez, J P; Ludovici, L; Lu, X; Magaletti, L; Mahn, K; Malek, M; Manly, S; Marino, A D; Marteau, J; Martin, J F; Martins, P; Martynenko, S; Maruyama, T; Matveev, V; Mavrokoridis, K; Ma, W Y; Mazzucato, E; McCarthy, M; McCauley, N; McFarland, K S; McGrew, C; Mefodiev, A; Metelko, C; Mezzetto, M; Mijakowski, P; Minamino, A; Mineev, O; Mine, S; Missert, A; Miura, M; Moriyama, S; Mueller, Th A; Murphy, S; Myslik, J; Nakadaira, T; Nakahata, M; Nakamura, K G; Nakamura, K; Nakamura, K D; Nakayama, S; Nakaya, T; Nakayoshi, K; Nantais, C; Nielsen, C; Nirkko, M; Nishikawa, K; Nishimura, Y; Novella, P; Nowak, J; O'Keeffe, H M; Ohta, R; Okumura, K; Okusawa, T; Oryszczak, W; Oser, S M; Ovsyannikova, T; Owen, R A; Oyama, Y; Palladino, V; Palomino, J L; Paolone, V; Patel, N D; Pavin, M; Payne, D; Perkin, J D; Petrov, Y; Pickard, L; Pickering, L; Pinzon Guerra, E S; Pistillo, C; Popov, B; Posiadala-Zezula, M; Poutissou, J-M; Poutissou, R; Przewlocki, P; Quilain, B; Radermacher, T; Radicioni, E; Ratoff, P N; Ravonel, M; Rayner, M A M; Redij, A; Reinherz-Aronis, E; Riccio, C; Rojas, P; Rondio, E; Roth, S; Rubbia, A; Rychter, A; Sacco, R; Sakashita, K; Sánchez, F; Sato, F; Scantamburlo, E; Scholberg, K; Schoppmann, S; Schwehr, J; Scott, M; Seiya, Y; Sekiguchi, T; Sekiya, H; Sgalaberna, D; Shah, R; Shaikhiev, A; Shaker, F; Shaw, D; Shiozawa, M; Shirahige, T; Short, S; Smy, M; Sobczyk, J T; Sobel, H; Sorel, M; Southwell, L; Stamoulis, P; Steinmann, J; Stewart, T; Stowell, P; Suda, Y; Suvorov, S; Suzuki, A; Suzuki, K; Suzuki, S Y; Suzuki, Y; Tacik, R; Tada, M; Takahashi, S; Takeda, A; Takeuchi, Y; Tanaka, H K; Tanaka, H A; Terhorst, D; Terri, R; Thakore, T; Thompson, L F; Tobayama, S; Toki, W; Tomura, T; Touramanis, C; Tsukamoto, T; Tzanov, M; Uchida, Y; Vacheret, A; Vagins, M; Vallari, Z; Vasseur, G; Wachala, T; Wakamatsu, K; Walter, C W; Wark, D; Warzycha, W; Wascko, M O; Weber, A; Wendell, R; Wilkes, R J; Wilking, M J; Wilkinson, C; Wilson, J R; Wilson, R J; Yamada, Y; Yamamoto, K; Yamamoto, M; Yanagisawa, C; Yano, T; Yen, S; Yershov, N; Yokoyama, M; Yoo, J; Yoshida, K; Yuan, T; Yu, M; Zalewska, A; Zalipska, J; Zambelli, L; Zaremba, K; Ziembicki, M; Zimmerman, E D; Zito, M; Żmuda, J
2016-11-04
We report the first measurement of the flux-averaged cross section for charged current coherent π^{+} production on carbon for neutrino energies less than 1.5 GeV, and with a restriction on the final state phase space volume in the T2K near detector, ND280. Comparisons are made with predictions from the Rein-Sehgal coherent production model and the model by Alvarez-Ruso et al., the latter representing the first implementation of an instance of the new class of microscopic coherent models in a neutrino interaction Monte Carlo event generator. We observe a clear event excess above background, disagreeing with the null results reported by K2K and SciBooNE in a similar neutrino energy region. The measured flux-averaged cross sections are below those predicted by both the Rein-Sehgal and Alvarez-Ruso et al.
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Measurement of Coherent π+ Production in Low Energy Neutrino-Carbon Scattering
NASA Astrophysics Data System (ADS)
Abe, K.; Andreopoulos, C.; Antonova, M.; Aoki, S.; Ariga, A.; Assylbekov, S.; Autiero, D.; Ban, S.; Barbi, M.; Barker, G. J.; Barr, G.; Bartet-Friburg, P.; Batkiewicz, M.; Bay, F.; Berardi, V.; Berkman, S.; Bhadra, S.; Blondel, A.; Bolognesi, S.; Bordoni, S.; Boyd, S. B.; Brailsford, D.; Bravar, A.; Bronner, C.; Buizza Avanzini, M.; Calland, R. G.; Campbell, T.; Cao, S.; Caravaca Rodríguez, J.; Cartwright, S. L.; Castillo, R.; Catanesi, M. G.; Cervera, A.; Cherdack, D.; Chikuma, N.; Christodoulou, G.; Clifton, A.; Coleman, J.; Collazuol, G.; Coplowe, D.; Cremonesi, L.; Dabrowska, A.; De Rosa, G.; Dealtry, T.; Denner, P. F.; Dennis, S. R.; Densham, C.; Dewhurst, D.; Di Lodovico, F.; Di Luise, S.; Dolan, S.; Drapier, O.; Duffy, K. E.; Dumarchez, J.; Dytman, S.; Dziewiecki, M.; Emery-Schrenk, S.; Ereditato, A.; Feusels, T.; Finch, A. J.; Fiorentini, G. A.; Friend, M.; Fujii, Y.; Fukuda, D.; Fukuda, Y.; Furmanski, A. P.; Galymov, V.; Garcia, A.; Giffin, S. G.; Giganti, C.; Gizzarelli, F.; Gonin, M.; Grant, N.; Hadley, D. R.; Haegel, L.; Haigh, M. D.; Hamilton, P.; Hansen, D.; Harada, J.; Hara, T.; Hartz, M.; Hasegawa, T.; Hastings, N. C.; Hayashino, T.; Hayato, Y.; Helmer, R. L.; Hierholzer, M.; Hillairet, A.; Himmel, A.; Hiraki, T.; Hirota, S.; Hogan, M.; Holeczek, J.; Horikawa, S.; Hosomi, F.; Huang, K.; Ichikawa, A. K.; Ieki, K.; Ikeda, M.; Imber, J.; Insler, J.; Intonti, R. A.; Irvine, T. J.; Ishida, T.; Ishii, T.; Iwai, E.; Iwamoto, K.; Izmaylov, A.; Jacob, A.; Jamieson, B.; Jiang, M.; Johnson, S.; Jo, J. H.; Jonsson, P.; Jung, C. K.; Kabirnezhad, M.; Kaboth, A. C.; Kajita, T.; Kakuno, H.; Kameda, J.; Karlen, D.; Karpikov, I.; Katori, T.; Kearns, E.; Khabibullin, M.; Khotjantsev, A.; Kielczewska, D.; Kikawa, T.; Kim, H.; Kim, J.; King, S.; Kisiel, J.; Knight, A.; Knox, A.; Kobayashi, T.; Koch, L.; Koga, T.; Konaka, A.; Kondo, K.; Kopylov, A.; Kormos, L. L.; Korzenev, A.; Koshio, Y.; Kropp, W.; Kudenko, Y.; Kurjata, R.; Kutter, T.; Lagoda, J.; Lamont, I.; Larkin, E.; Lasorak, P.; Laveder, M.; Lawe, M.; Lazos, M.; Lindner, T.; Liptak, Z. J.; Litchfield, R. P.; Li, X.; Longhin, A.; Lopez, J. P.; Ludovici, L.; Lu, X.; Magaletti, L.; Mahn, K.; Malek, M.; Manly, S.; Marino, A. D.; Marteau, J.; Martin, J. F.; Martins, P.; Martynenko, S.; Maruyama, T.; Matveev, V.; Mavrokoridis, K.; Ma, W. Y.; Mazzucato, E.; McCarthy, M.; McCauley, N.; McFarland, K. S.; McGrew, C.; Mefodiev, A.; Metelko, C.; Mezzetto, M.; Mijakowski, P.; Minamino, A.; Mineev, O.; Mine, S.; Missert, A.; Miura, M.; Moriyama, S.; Mueller, Th. A.; Murphy, S.; Myslik, J.; Nakadaira, T.; Nakahata, M.; Nakamura, K. G.; Nakamura, K.; Nakamura, K. D.; Nakayama, S.; Nakaya, T.; Nakayoshi, K.; Nantais, C.; Nielsen, C.; Nirkko, M.; Nishikawa, K.; Nishimura, Y.; Novella, P.; Nowak, J.; O'Keeffe, H. M.; Ohta, R.; Okumura, K.; Okusawa, T.; Oryszczak, W.; Oser, S. M.; Ovsyannikova, T.; Owen, R. A.; Oyama, Y.; Palladino, V.; Palomino, J. L.; Paolone, V.; Patel, N. D.; Pavin, M.; Payne, D.; Perkin, J. D.; Petrov, Y.; Pickard, L.; Pickering, L.; Pinzon Guerra, E. S.; Pistillo, C.; Popov, B.; Posiadala-Zezula, M.; Poutissou, J.-M.; Poutissou, R.; Przewlocki, P.; Quilain, B.; Radermacher, T.; Radicioni, E.; Ratoff, P. N.; Ravonel, M.; Rayner, M. A. M.; Redij, A.; Reinherz-Aronis, E.; Riccio, C.; Rojas, P.; Rondio, E.; Roth, S.; Rubbia, A.; Rychter, A.; Sacco, R.; Sakashita, K.; Sánchez, F.; Sato, F.; Scantamburlo, E.; Scholberg, K.; Schoppmann, S.; Schwehr, J.; Scott, M.; Seiya, Y.; Sekiguchi, T.; Sekiya, H.; Sgalaberna, D.; Shah, R.; Shaikhiev, A.; Shaker, F.; Shaw, D.; Shiozawa, M.; Shirahige, T.; Short, S.; Smy, M.; Sobczyk, J. T.; Sobel, H.; Sorel, M.; Southwell, L.; Stamoulis, P.; Steinmann, J.; Stewart, T.; Stowell, P.; Suda, Y.; Suvorov, S.; Suzuki, A.; Suzuki, K.; Suzuki, S. Y.; Suzuki, Y.; Tacik, R.; Tada, M.; Takahashi, S.; Takeda, A.; Takeuchi, Y.; Tanaka, H. K.; Tanaka, H. A.; Terhorst, D.; Terri, R.; Thakore, T.; Thompson, L. F.; Tobayama, S.; Toki, W.; Tomura, T.; Touramanis, C.; Tsukamoto, T.; Tzanov, M.; Uchida, Y.; Vacheret, A.; Vagins, M.; Vallari, Z.; Vasseur, G.; Wachala, T.; Wakamatsu, K.; Walter, C. W.; Wark, D.; Warzycha, W.; Wascko, M. O.; Weber, A.; Wendell, R.; Wilkes, R. J.; Wilking, M. J.; Wilkinson, C.; Wilson, J. R.; Wilson, R. J.; Yamada, Y.; Yamamoto, K.; Yamamoto, M.; Yanagisawa, C.; Yano, T.; Yen, S.; Yershov, N.; Yokoyama, M.; Yoo, J.; Yoshida, K.; Yuan, T.; Yu, M.; Zalewska, A.; Zalipska, J.; Zambelli, L.; Zaremba, K.; Ziembicki, M.; Zimmerman, E. D.; Zito, M.; Żmuda, J.; T2K Collaboration
2016-11-01
We report the first measurement of the flux-averaged cross section for charged current coherent π+ production on carbon for neutrino energies less than 1.5 GeV, and with a restriction on the final state phase space volume in the T2K near detector, ND280. Comparisons are made with predictions from the Rein-Sehgal coherent production model and the model by Alvarez-Ruso et al., the latter representing the first implementation of an instance of the new class of microscopic coherent models in a neutrino interaction Monte Carlo event generator. We observe a clear event excess above background, disagreeing with the null results reported by K2K and SciBooNE in a similar neutrino energy region. The measured flux-averaged cross sections are below those predicted by both the Rein-Sehgal and Alvarez-Ruso et al. models.
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Static vs. dynamic decoding algorithms in a non-invasive body-machine interface
Seáñez-González, Ismael; Pierella, Camilla; Farshchiansadegh, Ali; Thorp, Elias B.; Abdollahi, Farnaz; Pedersen, Jessica; Mussa-Ivaldi, Ferdinando A.
2017-01-01
In this study, we consider a non-invasive body-machine interface that captures body motions still available to people with spinal cord injury (SCI) and maps them into a set of signals for controlling a computer user interface while engaging in a sustained level of mobility and exercise. We compare the effectiveness of two decoding algorithms that transform a high-dimensional body-signal vector into a lower dimensional control vector on 6 subjects with high-level SCI and 8 controls. One algorithm is based on a static map from current body signals to the current value of the control vector set through principal component analysis (PCA), the other on dynamic mapping a segment of body signals to the value and the temporal derivatives of the control vector set through a Kalman filter. SCI and control participants performed straighter and smoother cursor movements with the Kalman algorithm during center-out reaching, but their movements were faster and more precise when using PCA. All participants were able to use the BMI’s continuous, two-dimensional control to type on a virtual keyboard and play pong, and performance with both algorithms was comparable. However, seven of eight control participants preferred PCA as their method of virtual wheelchair control. The unsupervised PCA algorithm was easier to train and seemed sufficient to achieve a higher degree of learnability and perceived ease of use. PMID:28092564
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Wu, Di; Klaw, Michelle C; Connors, Theresa; Kholodilov, Nikolai; Burke, Robert E; Côté, Marie-Pascale; Tom, Veronica J
2017-12-06
After spinal cord injury (SCI), severed axons in the adult mammalian CNS are unable to mount a robust regenerative response. In addition, the glial scar at the lesion site further restricts the regenerative potential of axons. We hypothesized that a combinatorial approach coincidentally targeting these obstacles would promote axonal regeneration. We combined (1) transplantation of a growth-permissive peripheral nerve graft (PNG) into an incomplete, cervical lesion cavity; (2) transduction of neurons rostral to the SCI site to express constitutively active Rheb (caRheb; a Ras homolog enriched in brain), a GTPase that directly activates the growth-promoting pathway mammalian target of rapamycin (mTOR) via AAV-caRheb injection; and (3) digestion of growth-inhibitory chondroitin sulfate proteoglycans within the glial scar at the distal PNG interface using the bacterial enzyme chondroitinase ABC (ChABC). We found that expressing caRheb in neurons post-SCI results in modestly yet significantly more axons regenerating across a ChABC-treated distal graft interface into caudal spinal cord than either treatment alone. Excitingly, we found that caRheb+ChABC treatment significantly potentiates the formation of synapses in the host spinal cord and improves the animals' ability to use the affected forelimb. Thus, this combination strategy enhances functional axonal regeneration following a cervical SCI. Copyright © 2017 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.
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Shahdoost, Shahab; Frost, Shawn; Dunham, Caleb; DeJong, Stacey; Barbay, Scott; Nudo, Randolph; Mohseni, Pedram
2015-08-01
Approximately 6 million people in the United States are currently living with paralysis in which 23% of the cases are related to spinal cord injury (SCI). Miniaturized closed-loop neural interfaces have the potential for restoring function and mobility lost to debilitating neural injuries such as SCI by leveraging recent advancements in bioelectronics and a better understanding of the processes that underlie functional and anatomical reorganization in an injured nervous system. This paper describes our current progress toward developing a miniaturized brain-machine-spinal cord interface (BMSI) that converts in real time the neural command signals recorded from the cortical motor regions to electrical stimuli delivered to the spinal cord below the injury level. Using a combination of custom integrated circuit (IC) technology for corticospinal interfacing and field-programmable gate array (FPGA)-based technology for embedded signal processing, we demonstrate proof-of-concept of distinct muscle pattern activation via intraspinal microstimulation (ISMS) controlled in real time by intracortical neural spikes in an anesthetized laboratory rat.
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Role of coherence and delocalization in photo-induced electron transfer at organic interfaces
NASA Astrophysics Data System (ADS)
Abramavicius, V.; Pranculis, V.; Melianas, A.; Inganäs, O.; Gulbinas, V.; Abramavicius, D.
2016-09-01
Photo-induced charge transfer at molecular heterojunctions has gained particular interest due to the development of organic solar cells (OSC) based on blends of electron donating and accepting materials. While charge transfer between donor and acceptor molecules can be described by Marcus theory, additional carrier delocalization and coherent propagation might play the dominant role. Here, we describe ultrafast charge separation at the interface of a conjugated polymer and an aggregate of the fullerene derivative PCBM using the stochastic Schrödinger equation (SSE) and reveal the complex time evolution of electron transfer, mediated by electronic coherence and delocalization. By fitting the model to ultrafast charge separation experiments, we estimate the extent of electron delocalization and establish the transition from coherent electron propagation to incoherent hopping. Our results indicate that even a relatively weak coupling between PCBM molecules is sufficient to facilitate electron delocalization and efficient charge separation at organic interfaces.
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Multi-facetted Metadata - Describing datasets with different metadata schemas at the same time
NASA Astrophysics Data System (ADS)
Ulbricht, Damian; Klump, Jens; Bertelmann, Roland
2013-04-01
Inspired by the wish to re-use research data a lot of work is done to bring data systems of the earth sciences together. Discovery metadata is disseminated to data portals to allow building of customized indexes of catalogued dataset items. Data that were once acquired in the context of a scientific project are open for reappraisal and can now be used by scientists that were not part of the original research team. To make data re-use easier, measurement methods and measurement parameters must be documented in an application metadata schema and described in a written publication. Linking datasets to publications - as DataCite [1] does - requires again a specific metadata schema and every new use context of the measured data may require yet another metadata schema sharing only a subset of information with the meta information already present. To cope with the problem of metadata schema diversity in our common data repository at GFZ Potsdam we established a solution to store file-based research data and describe these with an arbitrary number of metadata schemas. Core component of the data repository is an eSciDoc infrastructure that provides versioned container objects, called eSciDoc [2] "items". The eSciDoc content model allows assigning files to "items" and adding any number of metadata records to these "items". The eSciDoc items can be submitted, revised, and finally published, which makes the data and metadata available through the internet worldwide. GFZ Potsdam uses eSciDoc to support its scientific publishing workflow, including mechanisms for data review in peer review processes by providing temporary web links for external reviewers that do not have credentials to access the data. Based on the eSciDoc API, panMetaDocs [3] provides a web portal for data management in research projects. PanMetaDocs, which is based on panMetaWorks [4], is a PHP based web application that allows to describe data with any XML-based schema. It uses the eSciDoc infrastructures REST-interface to store versioned dataset files and metadata in a XML-format. The software is able to administrate more than one eSciDoc metadata record per item and thus allows the description of a dataset according to its context. The metadata fields can be filled with static or dynamic content to reduce the number of fields that require manual entries to a minimum and, at the same time, make use of contextual information available in a project setting. Access rights can be adjusted to set visibility of datasets to the required degree of openness. Metadata from separate instances of panMetaDocs can be syndicated to portals through RSS and OAI-PMH interfaces. The application architecture presented here allows storing file-based datasets and describe these datasets with any number of metadata schemas, depending on the intended use case. Data and metadata are stored in the same entity (eSciDoc items) and are managed by a software tool through the eSciDoc REST interface - in this case the application is panMetaDocs. Other software may re-use the produced items and modify the appropriate metadata records by accessing the web API of the eSciDoc data infrastructure. For presentation of the datasets in a web browser we are not bound to panMetaDocs. This is done by stylesheet transformation of the eSciDoc-item. [1] http://www.datacite.org [2] http://www.escidoc.org , eSciDoc, FIZ Karlruhe, Germany [3] http://panmetadocs.sf.net , panMetaDocs, GFZ Potsdam, Germany [4] http://metaworks.pangaea.de , panMetaWorks, Dr. R. Huber, MARUM, Univ. Bremen, Germany
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Exploring the Repeated Name Penalty and the Overt Pronoun Penalty in Spanish
ERIC Educational Resources Information Center
Gelormini-Lezama, Carlos
2018-01-01
Anaphoric expressions such as repeated names, overt pronouns, and null pronouns serve a major role in the creation and maintenance of discourse coherence. The felicitous use of an anaphoric expression is highly dependent on the discourse salience of the entity introduced by the antecedent. Gordon et al. ("Cogn Sci" 17:311-347, 1993)…
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Coherent Plasmon-Exciton Coupling in Silver Platelet-J-aggregate Nanocomposites
2015-02-27
2011, 11, 1556−1560. (12) Zengin, G.; Johansson, G.; Johansson, P.; Antosiewics, T. J.; Kall , M.; Shegai, T. Sci. Rep. 2013, 3 (3074), 1−8. (13...Mater. 2005, 17, 412−415. (21) Davydov, A. S. Theory of Molecular Excitons; Plenum Press: New York, 1971 . (22) Van Burgel, M.; Wiersma, D. A.; Duppen, K
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Framework for non-coherent interface models at finite displacement jumps and finite strains
NASA Astrophysics Data System (ADS)
Ottosen, Niels Saabye; Ristinmaa, Matti; Mosler, Jörn
2016-05-01
This paper deals with a novel constitutive framework suitable for non-coherent interfaces, such as cracks, undergoing large deformations in a geometrically exact setting. For this type of interface, the displacement field shows a jump across the interface. Within the engineering community, so-called cohesive zone models are frequently applied in order to describe non-coherent interfaces. However, for existing models to comply with the restrictions imposed by (a) thermodynamical consistency (e.g., the second law of thermodynamics), (b) balance equations (in particular, balance of angular momentum) and (c) material frame indifference, these models are essentially fiber models, i.e. models where the traction vector is collinear with the displacement jump. This constraints the ability to model shear and, in addition, anisotropic effects are excluded. A novel, extended constitutive framework which is consistent with the above mentioned fundamental physical principles is elaborated in this paper. In addition to the classical tractions associated with a cohesive zone model, the main idea is to consider additional tractions related to membrane-like forces and out-of-plane shear forces acting within the interface. For zero displacement jump, i.e. coherent interfaces, this framework degenerates to existing formulations presented in the literature. For hyperelasticity, the Helmholtz energy of the proposed novel framework depends on the displacement jump as well as on the tangent vectors of the interface with respect to the current configuration - or equivalently - the Helmholtz energy depends on the displacement jump and the surface deformation gradient. It turns out that by defining the Helmholtz energy in terms of the invariants of these variables, all above-mentioned fundamental physical principles are automatically fulfilled. Extensions of the novel framework necessary for material degradation (damage) and plasticity are also covered.
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Abdollahi, Farnaz; Farshchiansadegh, Ali; Pierella, Camilla; Seáñez-González, Ismael; Thorp, Elias; Lee, Mei-Hua; Ranganathan, Rajiv; Pedersen, Jessica; Chen, David; Roth, Elliot; Casadio, Maura; Mussa-Ivaldi, Ferdinando
2017-05-01
This study tested the use of a customized body-machine interface (BoMI) for enhancing functional capabilities in persons with cervical spinal cord injury (cSCI). The interface allows people with cSCI to operate external devices by reorganizing their residual movements. This was a proof-of-concept phase 0 interventional nonrandomized clinical trial. Eight cSCI participants wore a custom-made garment with motion sensors placed on the shoulders. Signals derived from the sensors controlled a computer cursor. A standard algorithm extracted the combinations of sensor signals that best captured each participant's capacity for controlling a computer cursor. Participants practiced with the BoMI for 24 sessions over 12 weeks performing 3 tasks: reaching, typing, and game playing. Learning and performance were evaluated by the evolution of movement time, errors, smoothness, and performance metrics specific to each task. Through practice, participants were able to reduce the movement time and the distance from the target at the 1-second mark in the reaching task. They also made straighter and smoother movements while reaching to different targets. All participants became faster in the typing task and more skilled in game playing, as the pong hit rate increased significantly with practice. The results provide proof-of-concept for the customized BoMI as a means for people with absent or severely impaired hand movements to control assistive devices that otherwise would be manually operated.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Eftink, Benjamin P.; Li, Ao; Szlufarska, I.
The mechanisms of strain transfer across Ag/Cu interfaces were determined by a combination of in situ and ex situ TEM straining experiments and molecular dynamics simulations. Minimizing the magnitude of the Burgers vector of the residual dislocation generated in the interface was the dominant factor for determining the outcome of dislocation and deformation twin interactions with both non-coherent twin and cube-on-cube interfaces. This included the unexpected finding, due to the loading condition, of deformation twin activation in the Cu layer due to the intersection of deformation twins in Ag with the interface. As a result, deformation twin nucleation in Agmore » from the non-coherent twin interfaces was also explained by a Burgers vector minimization argument.« less
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Eftink, Benjamin P.; Li, Ao; Szlufarska, I.; ...
2017-07-29
The mechanisms of strain transfer across Ag/Cu interfaces were determined by a combination of in situ and ex situ TEM straining experiments and molecular dynamics simulations. Minimizing the magnitude of the Burgers vector of the residual dislocation generated in the interface was the dominant factor for determining the outcome of dislocation and deformation twin interactions with both non-coherent twin and cube-on-cube interfaces. This included the unexpected finding, due to the loading condition, of deformation twin activation in the Cu layer due to the intersection of deformation twins in Ag with the interface. As a result, deformation twin nucleation in Agmore » from the non-coherent twin interfaces was also explained by a Burgers vector minimization argument.« less
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A comparison of high-speed links, their commercial support and ongoing R&D activities
DOE Office of Scientific and Technical Information (OSTI.GOV)
Gonzalez, H.L.; Barsotti, E.; Zimmermann, S.
Technological advances and a demanding market have forced the development of higher bandwidth communication standards for networks, data links and busses. Most of these emerging standards are gathering enough momentum that their widespread availability and lower prices are anticipated. The hardware and software that support the physical media for most of these links is currently available, allowing the user community to implement fairly high-bandwidth data links and networks with commercial components. Also, switches needed to support these networks are available or being developed. The commercial suppose of high-bandwidth data links, networks and switching fabrics provides a powerful base for themore » implementation of high-bandwidth data acquisition systems. A large data acquisition system like the one for the Solenoidal Detector Collaboration (SDC) at the SSC can benefit from links and networks that support an integrated systems engineering approach, for initialization, downloading, diagnostics, monitoring, hardware integration and event data readout. The issue that our current work addresses is the possibility of having a channel/network that satisfies the requirements of an integrated data acquisition system. In this paper we present a brief description of high-speed communication links and protocols that we consider of interest for high energy physic High Performance Parallel Interface (HIPPI). Serial HIPPI, Fibre Channel (FC) and Scalable Coherent Interface (SCI). In addition, the initial work required to implement an SDC-like data acquisition system is described.« less
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A comparison of high-speed links, their commercial support and ongoing R D activities
DOE Office of Scientific and Technical Information (OSTI.GOV)
Gonzalez, H.L.; Barsotti, E.; Zimmermann, S.
Technological advances and a demanding market have forced the development of higher bandwidth communication standards for networks, data links and busses. Most of these emerging standards are gathering enough momentum that their widespread availability and lower prices are anticipated. The hardware and software that support the physical media for most of these links is currently available, allowing the user community to implement fairly high-bandwidth data links and networks with commercial components. Also, switches needed to support these networks are available or being developed. The commercial suppose of high-bandwidth data links, networks and switching fabrics provides a powerful base for themore » implementation of high-bandwidth data acquisition systems. A large data acquisition system like the one for the Solenoidal Detector Collaboration (SDC) at the SSC can benefit from links and networks that support an integrated systems engineering approach, for initialization, downloading, diagnostics, monitoring, hardware integration and event data readout. The issue that our current work addresses is the possibility of having a channel/network that satisfies the requirements of an integrated data acquisition system. In this paper we present a brief description of high-speed communication links and protocols that we consider of interest for high energy physic High Performance Parallel Interface (HIPPI). Serial HIPPI, Fibre Channel (FC) and Scalable Coherent Interface (SCI). In addition, the initial work required to implement an SDC-like data acquisition system is described.« less
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Shao, Shuai; Wang, Jian
In this work, using the Cu–Ni (111) semi-coherent interface as a model system, we combine atomistic simulations and defect theory to reveal the relaxation mechanisms, structure, and properties of semi-coherent interfaces. By calculating the generalized stacking fault energy (GSFE) profile of the interface, two stable structures and a high-energy structure are located. During the relaxation, the regions that possess the stable structures expand and develop into coherent regions; the regions with high-energy structure shrink into the intersection of misfit dislocations (nodes). This process reduces the interface excess potential energy but increases the core energy of the misfit dislocations and nodes.more » The core width is dependent on the GSFE of the interface. The high-energy structure relaxes by relative rotation and dilatation between the crystals. The relative rotation is responsible for the spiral pattern at nodes. The relative dilatation is responsible for the creation of free volume at nodes, which facilitates the nodes’ structural transformation. Several node structures have been observed and analyzed. In conclusion, the various structures have significant impact on the plastic deformation in terms of lattice dislocation nucleation, as well as the point defect formation energies.« less
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Ultra-compact coherent receiver with serial interface for pluggable transceiver.
Itoh, Toshihiro; Nakajima, Fumito; Ohno, Tetsuichiro; Yamanaka, Shogo; Soma, Shunichi; Saida, Takashi; Nosaka, Hideyuki; Murata, Koichi
2014-09-22
An ultra-compact integrated coherent receiver with a volume of 1.3 cc using a quad-channel transimpedance amplifier (TIA)-IC chip with a serial peripheral interface (SPI) is demonstrated for the first time. The TIA with the SPI and photodiode (PD) bias circuits, a miniature dual polarization optical hybrid, an octal-PD and small optical coupling system enabled the realization of the compact receiver. Measured transmission performance with 32 Gbaud dual-polarization quadrature phase shift keying signal is equivalent to that of the conventional multi-source agreement-based integrated coherent receiver with dual channel TIA-ICs. By comparing the bit-error rate (BER) performance with that under continuous SPI access, we also confirmed that there is no BER degradation caused by SPI interface access. Such an ultra-compact receiver is promising for realizing a new generation of pluggable transceivers.
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Kobayashi, Norio; Ishii, Manabu; Takahashi, Satoshi; Mochizuki, Yoshiki; Matsushima, Akihiro; Toyoda, Tetsuro
2011-07-01
Global cloud frameworks for bioinformatics research databases become huge and heterogeneous; solutions face various diametric challenges comprising cross-integration, retrieval, security and openness. To address this, as of March 2011 organizations including RIKEN published 192 mammalian, plant and protein life sciences databases having 8.2 million data records, integrated as Linked Open or Private Data (LOD/LPD) using SciNetS.org, the Scientists' Networking System. The huge quantity of linked data this database integration framework covers is based on the Semantic Web, where researchers collaborate by managing metadata across public and private databases in a secured data space. This outstripped the data query capacity of existing interface tools like SPARQL. Actual research also requires specialized tools for data analysis using raw original data. To solve these challenges, in December 2009 we developed the lightweight Semantic-JSON interface to access each fragment of linked and raw life sciences data securely under the control of programming languages popularly used by bioinformaticians such as Perl and Ruby. Researchers successfully used the interface across 28 million semantic relationships for biological applications including genome design, sequence processing, inference over phenotype databases, full-text search indexing and human-readable contents like ontology and LOD tree viewers. Semantic-JSON services of SciNetS.org are provided at http://semanticjson.org.
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Depth-Dependent Defect Studies Using Coherent Acoustic Phonons
2014-09-29
using CAP waves as an active moving interface to induce local changes in electric, acoustic , and optical properties. This is able to generate ultrafast...the elastic strain component [6]. b) Modification of the crystal lattice due to transient strain caused by the coherent acoustic phonon wave . The...opto-electronic properties of materials. We are also using CAP waves as an active moving interface to induce local changes in electric, acoustic , and
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Prevention of Pressure Ulcers Among People With Spinal Cord Injury: A Systematic Review.
Groah, Suzanne L; Schladen, Manon; Pineda, Cynthia G; Hsieh, Ching-Hui J
2015-06-01
To evaluate the literature on the effectiveness of bed and wheelchair positioning and repositioning in the prevention of pressure ulcers (PUs) in both the spinal cord injury (SCI) and non-SCI populations. Systematic review. PubMed, CINAHL, PsycINFO, and EMBASE were queried with the subject heading terms "pressure sore," "pressure ulcer," "position or turn in bed, wheelchair," "pressure relief," and "pressure release." All study design types that assessed the effectiveness of bed and wheelchair positioning and pressure relief maneuvers in any patient group and in any setting were sought. Three independent reviewers extracted and summarized details of eligible trials using a standardized method. Two independent reviewers assessed the methodological quality of each trial using the American Academy of Neurology guidelines. When reviewers were not able to reach consensus, a third independent reviewer served as tiebreaker. We identified 2820 publications, of which 49 met inclusion criteria. Of these publications, the subject population was 2834 (923 persons with SCI, 717 persons without SCI, and 1194 healthy control subjects). Among studies examining pressure related to position or repositioning in bed or sitting, procedures for measuring skin pressure and metabolism were highly variable by anatomic location, measurement technique, outcome measure, study site, participant characteristics, and description of position/turning for bed and seated interventions. Numerous factors can influence tissue interface pressures, and no prospective studies had been performed to determine a causal relationship between interface pressure and skin breakdown. Several studies suggest that skin response to pressure differs between subjects with and without SCI. Conflicting results and insufficient evidence for optimal bed and seated positioning and turning and pressure relief maneuvers to prevent PUs in both SCI and non-SCI populations were limiting factors. Although there is no clear optimal positioning or turning frequency in bed, the evidence suggests avoiding the 90° lateral position because of high pressures and PU risk over the trochanters. During sitting, pressures are linearly redistributed from the sitting area during recline and tilt; however, reclining carries with it an increased risk of shear forces on this skin. The evidence does not support conclusive guidelines on positioning or repositioning techniques for PU prevention in bed or during sitting. We conclude that PU risk is highly individualized, with the SCI population at a higher risk, which demands flexible PU prevention strategies for bed/seated positioning and pressure relief maneuvers. Education has and will remain our most powerful ally to thwart this pervasive public health problem. Copyright © 2015. Published by Elsevier Inc.
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An analysis of quantum coherent solar photovoltaic cells
NASA Astrophysics Data System (ADS)
Kirk, A. P.
2012-02-01
A new hypothesis (Scully et al., Proc. Natl. Acad. Sci. USA 108 (2011) 15097) suggests that it is possible to break the statistical physics-based detailed balance-limiting power conversion efficiency and increase the power output of a solar photovoltaic cell by using “noise-induced quantum coherence” to increase the current. The fundamental errors of this hypothesis are explained here. As part of this analysis, we show that the maximum photogenerated current density for a practical solar cell is a function of the incident spectrum, sunlight concentration factor, and solar cell energy bandgap and thus the presence of quantum coherence is irrelevant as it is unable to lead to increased current output from a solar cell.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Shutthanandan, Vaithiyalingam; Choudhury, Samrat; Manandhar, Sandeep
To understand how variations in interface properties such as misfit-dislocation density and local chemistry affect radiation-induced defect absorption and recombination, we have explored a model system of CrxV1-x alloy epitaxial films deposited on MgO single crystals. By controlling film composition, the lattice mismatch with MgO was adjusted so that the misfit-dislocation density varies at the interface. These interfaces were exposed to irradiation and in situ results show that the film with a semi-coherent interface (Cr) withstands irradiation while V film, which has similar semi-coherent interface like Cr, showed the largest damage. Theoretical calculations indicate that, unlike at metal/metal interfaces, themore » misfit dislocation density does not dominate radiation damage tolerance at metal/oxide interfaces. Rather, the stoichiometry, and the precise location of the misfit-dislocation density relative to the interface, drives defect behavior. Together, these results demonstrate the sensitivity of defect recombination to interfacial chemistry and provide new avenues for engineering radiation-tolerant nanomaterials.« less
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Preserving transfer independence among individuals with spinal cord injury.
Nyland, J; Quigley, P; Huang, C; Lloyd, J; Harrow, J; Nelson, A
2000-11-01
Literature review. Upper extremity (UE) joint degeneration, particularly at the shoulder, detrimentally influences functional independence, quality of life, cardiovascular disease risk, and life expectancy of individuals following spinal cord injury (SCI). This review (1) describes UE use for transfers among individuals with SCI; (2) describes contributing factors associated with UE joint degeneration and loss of transfer independence; (3) summarizes and identifies gaps in existing research; and (4) provides suggestions for future research. Investigations of wheelchair transfer related UE joint and function preservation among individuals with SCI should consider factors including age and length of time from SCI onset, interface between subject-wheelchair, pain, shoulder joint range of motion (ROM) and muscle strength deficiencies or imbalances, exercise capacity and tolerance for the physical strain of activities of daily living (ADL), body mass and composition, previous UE injury or disease history, and transfer techniques. Existing studies of transfers among individuals with SCI have relied on small groups of either asymptomatic or non-impaired subjects, with minimal integration of kinematic, kinetic and electromyographic data. Descriptions of UE joint ROM, forces, and moments produced during transfers are lacking. Biomechanical measurement and computer modeling have provided increasingly accurate tools for acquiring the data needed to guide intervention planning to prevent UE joint degeneration and preserve function among individuals with SCI. The identification of stressful sub-components during transfers will enable intervening clinicians and engineers who design and modify assistive and adaptive devices to better serve individuals with SCI.
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Smit, C A J; Haverkamp, G L G; de Groot, S; Stolwijk-Swuste, J M; Janssen, T W J
2012-08-01
Ten participants underwent two electrical stimulation (ES) protocols applied using a custom-made electrode garment with built-in electrodes. Interface pressure was measured using a force-sensitive area. In one protocol, both the gluteal and hamstring (g+h) muscles were activated, in the other gluteal (g) muscles only. To study and compare the effects of electrically induced activation of g+h muscles versus g muscles only on sitting pressure distribution in individuals with a spinal cord injury (SCI). Ischial tuberosities interface pressure (ITs pressure) and pressure gradient. In all participants, both protocols of g and g+h ES-induced activation caused a significant decrease in IT pressure. IT pressure after g+h muscles activation was reduced significantly by 34.5% compared with rest pressure, whereas a significant reduction of 10.2% after activation of g muscles only was found. Pressure gradient reduced significantly only after stimulation of g+h muscles (49.3%). g+h muscles activation showed a decrease in pressure relief (Δ IT) over time compared with g muscles only. Both protocols of surface ES-induced of g and g+h activation gave pressure relief from the ITs. Activation of both g+h muscles in SCI resulted in better IT pressure reduction in sitting individuals with a SCI than activation of g muscles only. ES might be a promising method in preventing pressure ulcers (PUs) on the ITs in people with SCI. Further research needs to show which pressure reduction is sufficient in preventing PUs.
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A rodent brain-machine interface paradigm to study the impact of paraplegia on BMI performance.
Bridges, Nathaniel R; Meyers, Michael; Garcia, Jonathan; Shewokis, Patricia A; Moxon, Karen A
2018-05-31
Most brain machine interfaces (BMI) focus on upper body function in non-injured animals, not addressing the lower limb functional needs of those with paraplegia. A need exists for a novel BMI task that engages the lower body and takes advantage of well-established rodent spinal cord injury (SCI) models to study methods to improve BMI performance. A tilt BMI task was designed that randomly applies different types of tilts to a platform, decodes the tilt type applied and rights the platform if the decoder correctly classifies the tilt type. The task was tested on female rats and is relatively natural such that it does not require the animal to learn a new skill. It is self-rewarding such that there is no need for additional rewards, eliminating food or water restriction, which can be especially hard on spinalized rats. Finally, task difficulty can be adjusted by making the tilt parameters. This novel BMI task bilaterally engages the cortex without visual feedback regarding limb position in space and animals learn to improve their performance both pre and post-SCI.Comparison with Existing Methods: Most BMI tasks primarily engage one hemisphere, are upper-body, rely heavily on visual feedback, do not perform investigations in animal models of SCI, and require nonnaturalistic extrinsic motivation such as water rewarding for performance improvement. Our task addresses these gaps. The BMI paradigm presented here will enable researchers to investigate the interaction of plasticity after SCI and plasticity during BMI training on performance. Copyright © 2018. Published by Elsevier B.V.
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Glide dislocation nucleation from dislocation nodes at semi-coherent {111} Cu–Ni interfaces
Shao, Shuai; Wang, Jian; Beyerlein, Irene J.; ...
2015-07-23
Using atomistic simulations and dislocation theory on a model system of semi-coherent {1 1 1} interfaces, we show that misfit dislocation nodes adopt multiple atomic arrangements corresponding to the creation and redistribution of excess volume at the nodes. We identified four distinctive node structures: volume-smeared nodes with (i) spiral or (ii) straight dislocation patterns, and volume-condensed nodes with (iii) triangular or (iv) hexagonal dislocation patterns. Volume-smeared nodes contain interfacial dislocations lying in the Cu–Ni interface but volume-condensed nodes contain two sets of interfacial dislocations in the two adjacent interfaces and jogs across the atomic layer between the two adjacent interfaces.more » Finally, under biaxial tension/compression applied parallel to the interface, we show that the nucleation of lattice dislocations is preferred at the nodes and is correlated with the reduction of excess volume at the nodes.« less
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Hu, Chongze; Huang, Jingsong; Sumpter, Bobby G.
Conceiving strong interfaces represents an effective direction in the development of superhard nanocomposite materials for practical applications in protective coatings. Additionally, in the pursuit of engineering strong nanoscale interfaces between cubic rock-salt (B1) domains, we investigate using density functional theory (DFT) coherent interface models designed based on hexagonal (HX) NiAs and WC structures, as well as experiment. The DFT screening of a collection of transition-metal (M = Zr, Hf, Nb, Ta) carbides and nitrides indicates that the interface models provided by the HX polymorphs store little coherency strain and develop an energetic advantage as the valence-electron concentration increases. Finally, ourmore » result suggests that harnessing the polymorphism encountered in transition-metal (M = Zr, Hf, Nb, Ta) carbides and nitrides for interface design represents a promising strategy for advancing superhard nanomaterials.« less
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Hu, Chongze; Huang, Jingsong; Sumpter, Bobby G.; ...
2018-04-19
Conceiving strong interfaces represents an effective direction in the development of superhard nanocomposite materials for practical applications in protective coatings. Additionally, in the pursuit of engineering strong nanoscale interfaces between cubic rock-salt (B1) domains, we investigate using density functional theory (DFT) coherent interface models designed based on hexagonal (HX) NiAs and WC structures, as well as experiment. The DFT screening of a collection of transition-metal (M = Zr, Hf, Nb, Ta) carbides and nitrides indicates that the interface models provided by the HX polymorphs store little coherency strain and develop an energetic advantage as the valence-electron concentration increases. Finally, ourmore » result suggests that harnessing the polymorphism encountered in transition-metal (M = Zr, Hf, Nb, Ta) carbides and nitrides for interface design represents a promising strategy for advancing superhard nanomaterials.« less
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The coherent interlayer resistance of a single, rotated interface between two stacks of AB graphite
NASA Astrophysics Data System (ADS)
Habib, K. M. Masum; Sylvia, Somaia S.; Ge, Supeng; Neupane, Mahesh; Lake, Roger K.
2013-12-01
The coherent, interlayer resistance of a misoriented, rotated interface between two stacks of AB graphite is determined for a variety of misorientation angles. The quantum-resistance of the ideal AB stack is on the order of 1 to 10 mΩ μm2. For small rotation angles, the coherent interlayer resistance exponentially approaches the ideal quantum resistance at energies away from the charge neutrality point. Over a range of intermediate angles, the resistance increases exponentially with cell size for minimum size unit cells. Larger cell sizes, of similar angles, may not follow this trend. The energy dependence of the interlayer transmission is described.
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Inflammation-related alterations of lipids after spinal cord injury revealed by Raman spectroscopy
NASA Astrophysics Data System (ADS)
Tamosaityte, Sandra; Galli, Roberta; Uckermann, Ortrud; Sitoci-Ficici, Kerim H.; Koch, Maria; Later, Robert; Schackert, Gabriele; Koch, Edmund; Steiner, Gerald; Kirsch, Matthias
2016-06-01
Spinal cord injury (SCI) triggers several lipid alterations in nervous tissue. It is characterized by extensive demyelination and the inflammatory response leads to accumulation of activated microglia/macrophages, which often transform into foam cells by accumulation of lipid droplets after engulfment of the damaged myelin sheaths. Using an experimental rat model, Raman microspectroscopy was applied to retrieve the modifications of the lipid distribution following SCI. Coherent anti-Stokes Raman scattering (CARS) and endogenous two-photon fluorescence (TPEF) microscopies were used for the detection of lipid-laden inflammatory cells. The Raman mapping of CH2 deformation mode intensity at 1440 cm-1 retrieved the lipid-depleted injury core. Preserved white matter and inflammatory regions with myelin fragmentation and foam cells were localized by specifically addressing the distribution of esterified lipids, i.e., by mapping the intensity of the carbonyl Raman band at 1743 cm-1, and were in agreement with CARS/TPEF microscopy. Principal component analysis revealed that the inflammatory regions are notably rich in saturated fatty acids. Therefore, Raman spectroscopy enabled to specifically detect inflammation after SCI and myelin degradation products.
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Advanced Coatings from Natural-Based Polymers for Metals
2000-07-01
Polyimide Interfaces," J. surfaces using a simple dipping-withdrawing coating Vac. Sci. Technol., 3,1390 (1985).converted into the solid layers by heat...Tang, C.H., "Interface Reaction During Metalliza- more, the Al metal in the substrate favorably interacted tion of Cured Polyimide : An XPS Study," 1...property together with its biocompatability was the reason why CS is widely used in biomedical applications, for example, a bacteriostatic agent, a
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Makhsous, Mohsen; Priebe, Michael; Bankard, James; Rowles, Diana; Zeigler, Mary; Chen, David; Lin, Fang
2007-01-01
Background/Objective: To study the effect on tissue perfusion of relieving interface pressure using standard wheelchair pushups compared with a mechanical automated dynamic pressure relief system. Design: Repeated measures in 2 protocols on 3 groups of subjects. Participants: Twenty individuals with motor-complete paraplegia below T4, 20 with motor-complete tetraplegia, and 20 able-bodied subjects. Methods: Two 1-hour sitting protocols: dynamic protocol, sitting configuration alternated every 10 minutes between a normal sitting configuration and an off-loading configuration; wheelchair pushup protocol, normal sitting configuration with standard wheelchair pushup once every 20 minutes. Main Outcome Measures: Transcutaneous partial pressures of oxygen and carbon dioxide measured from buttock overlying the ischial tuberosity and interface pressure measured at the seat back and buttocks. Perfusion deterioration and recovery times were calculated during changes in interface pressures. Results: In the off-loading configuration, concentrated interface pressure during the normal sitting configuration was significantly diminished, and tissue perfusion was significantly improved. Wheelchair pushups showed complete relief of interface pressure but incomplete recovery of tissue perfusion. Conclusions: Interface pressure analysis does not provide complete information about the effectiveness of pressure relief maneuvers. Measures of tissue perfusion may help establish more effective strategies. Relief achieved by standard wheelchair pushups may not be sufficient to recover tissue perfusion compromised during sitting; alternate maneuvers may be necessary. The dynamic seating system provided effective pressure relief with sustained reduction in interface pressure adequate for complete recovery of tissue perfusion. Differences in perfusion recovery times between subjects with spinal cord injury (SCI) and controls raise questions about the importance of changes in vascular responses to pressure after SCI. PMID:18092567
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Chemical Bonding, Interdiffusion and Electronic Structure at InP, GaAs, and Si-Metal Interfaces.
1985-10-01
4. H.H. Wieder, J. Vac. Sci. Technol. 15, 1498 (1978). C. 5. W.E. Spicer, 1. Lindau, P. Skeath, C.Y. Su, and P. Chye , Phys. Rev. Lett. 44, 10 420...Spicer, Solid State Electron. 28 307 (1985). 25. N. Newman, K.K. Chin , W.G. Petro, T. Kendelewicz, M.D. Williams, C.E. McCants, and W.E. Spicer, J. Vac...Technol. 19, 661 (1981). 11. Y. Shapira, L.J. Brillson and A. Heller, J. Vac. Sci. U Technol., Al, 766 (1983). 12. P.W. Chye , I. Lindau, P. Pianetta, C.M
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A Rigorous Sharp Interface Limit of a Diffuse Interface Model Related to Tumor Growth
NASA Astrophysics Data System (ADS)
Rocca, Elisabetta; Scala, Riccardo
2017-06-01
In this paper, we study the rigorous sharp interface limit of a diffuse interface model related to the dynamics of tumor growth, when a parameter ɛ, representing the interface thickness between the tumorous and non-tumorous cells, tends to zero. More in particular, we analyze here a gradient-flow-type model arising from a modification of the recently introduced model for tumor growth dynamics in Hawkins-Daruud et al. (Int J Numer Math Biomed Eng 28:3-24, 2011) (cf. also Hilhorst et al. Math Models Methods Appl Sci 25:1011-1043, 2015). Exploiting the techniques related to both gradient flows and gamma convergence, we recover a condition on the interface Γ relating the chemical and double-well potentials, the mean curvature, and the normal velocity.
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New Diamond Color Center for Quantum Communication
NASA Astrophysics Data System (ADS)
Huang, Ding; Rose, Brendon; Tyryshkin, Alexei; Sangtawesin, Sorawis; Srinivasan, Srikanth; Twitchen, Daniel; Markham, Matthew; Edmonds, Andrew; Gali, Adam; Stacey, Alastair; Wang, Wuyi; D'Haenens-Johansson, Ulrika; Zaitsev, Alexandre; Lyon, Stephen; de Leon, Nathalie
2017-04-01
Color centers in diamond are attractive for quantum communication applications because of their long electron spin coherence times and efficient optical transitions. Previous demonstrations of color centers as solid-state spin qubits were primarily focused on centers that exhibit either long coherence times or highly efficient optical interfaces. Recently, we developed a method to stabilize the neutral charge state of silicon-vacancy center in diamond (SiV0) with high conversion efficiency. We observe spin relaxation times exceeding 1 minute and spin coherence times of 1 ms for SiV0 centers. Additionally, the SiV0 center also has > 90 % of its emission into its zero-phonon line and a narrow inhomogeneous optical linewidth. The combination of a long spin coherence time and efficient optical interface make the SiV0 center a promising candidate for applications in long distance quantum communication.
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Kobayashi, Norio; Ishii, Manabu; Takahashi, Satoshi; Mochizuki, Yoshiki; Matsushima, Akihiro; Toyoda, Tetsuro
2011-01-01
Global cloud frameworks for bioinformatics research databases become huge and heterogeneous; solutions face various diametric challenges comprising cross-integration, retrieval, security and openness. To address this, as of March 2011 organizations including RIKEN published 192 mammalian, plant and protein life sciences databases having 8.2 million data records, integrated as Linked Open or Private Data (LOD/LPD) using SciNetS.org, the Scientists' Networking System. The huge quantity of linked data this database integration framework covers is based on the Semantic Web, where researchers collaborate by managing metadata across public and private databases in a secured data space. This outstripped the data query capacity of existing interface tools like SPARQL. Actual research also requires specialized tools for data analysis using raw original data. To solve these challenges, in December 2009 we developed the lightweight Semantic-JSON interface to access each fragment of linked and raw life sciences data securely under the control of programming languages popularly used by bioinformaticians such as Perl and Ruby. Researchers successfully used the interface across 28 million semantic relationships for biological applications including genome design, sequence processing, inference over phenotype databases, full-text search indexing and human-readable contents like ontology and LOD tree viewers. Semantic-JSON services of SciNetS.org are provided at http://semanticjson.org. PMID:21632604
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Radiation response of oxide-dispersion-strengthened alloy MA956 after self-ion irradiation
NASA Astrophysics Data System (ADS)
Chen, Tianyi; Kim, Hyosim; Gigax, Jonathan G.; Chen, Di; Wei, Chao-Chen; Garner, F. A.; Shao, Lin
2017-10-01
We studied the radiation-induced microstructural evolution of an oxide-dispersion-strengthened (ODS) ferritic alloy, MA956, to 180 dpa using 3.5 MeV Fe2+ ions. Post-irradiation examination showed that voids formed rather early and almost exclusively at the particle-matrix interfaces. Surprisingly, voids formed even in the injected interstitial zone. Comparisons with studies on other ODS alloys with smaller and largely coherent dispersoids irradiated at similar conditions revealed that the larger and not completely coherent oxide particles in MA956 serve as defect collectors which promote nucleation of voids at their interface. The interface configuration, which is related to particle type, crystal structure and size, is one of the important factors determining the defect-sink properties of particle-matrix interfaces.
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Non-uniform solute segregation at semi-coherent metal/oxide interfaces
Choudhury, Samrat; Aguiar, Jeffery A.; Fluss, Michael J.; ...
2015-08-26
The properties and performance of metal/oxide nanocomposites are governed by the structure and chemistry of the metal/oxide interfaces. Here we report an integrated theoretical and experimental study examining the role of interfacial structure, particularly misfit dislocations, on solute segregation at a metal/oxide interface. We find that the local oxygen environment, which varies significantly between the misfit dislocations and the coherent terraces, dictates the segregation tendency of solutes to the interface. Depending on the nature of the solute and local oxygen content, segregation to misfit dislocations can change from attraction to repulsion, revealing the complex interplay between chemistry and structure atmore » metal/oxide interfaces. These findings indicate that the solute chemistry at misfit dislocations is controlled by the dislocation density and oxygen content. As a result, fundamental thermodynamic concepts – the Hume-Rothery rules and the Ellingham diagram – qualitatively predict the segregation behavior of solutes to such interfaces, providing design rules for novel interfacial chemistries.« less
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Enhancing neural activity to drive respiratory plasticity following cervical spinal cord injury
Hormigo, Kristiina M.; Zholudeva, Lyandysha V.; Spruance, Victoria M.; Marchenko, Vitaliy; Cote, Marie-Pascale; Vinit, Stephane; Giszter, Simon; Bezdudnaya, Tatiana; Lane, Michael A.
2016-01-01
Cervical spinal cord injury (SCI) results in permanent life-altering sensorimotor deficits, among which impaired breathing is one of the most devastating and life-threatening. While clinical and experimental research has revealed that some spontaneous respiratory improvement (functional plasticity) can occur post-SCI, the extent of the recovery is limited and significant deficits persist. Thus, increasing effort is being made to develop therapies that harness and enhance this neuroplastic potential to optimize long-term recovery of breathing in injured individuals. One strategy with demonstrated therapeutic potential is the use of treatments that increase neural and muscular activity (e.g. locomotor training, neural and muscular stimulation) and promote plasticity. With a focus on respiratory function post-SCI, this review will discuss advances in the use of neural interfacing strategies and activity-based treatments, and highlights some recent results from our own research. PMID:27582085
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AGWA: The Automated Geospatial Watershed Assessment Tool
The Automated Geospatial Watershed Assessment Tool (AGWA, see: www.tucson.ars.ag.gov/agwa or http://www.epa.gov/esd/land-sci/agwa/) is a GIS interface jointly developed by the USDA-Agricultural Research Service, the U.S. Environmental Protection Agency, the University of Arizona...
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Automated Geospatial Watershed Assessment Tool (AGWA) Poster Presentation
The Automated Geospatial Watershed Assessment tool (AGWA, see: www.tucson.ars.ag.gov/agwa or http://www.epa.gov/esd/land-sci/agwa/) is a GIS interface jointly developed by the USDA-Agricultural Research Service, the U.S. Environmental Protection Agency, the University of Arizona...
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Topological interface physics in spinor Bose-Einstein condensates
NASA Astrophysics Data System (ADS)
Borgh, Magnus; Ruostekoski, Janne
2013-05-01
We present an experimentally viable scheme whereby the physics of coherent interfaces between topologically distinct regions can be studied in an atomic quantum gas. The interface engineering is achieved using the internal spin structures of atoms together with local control over interaction strengths. We consider a coherent interface between polar and ferromagnetic regions of a spin-1 Bose-Einstein condensate and show that defects representing different topologies can connect continuously across the boundary. We show that energy minimization leads to nontrivial interface-crossing defect structures, demonstrating how the method can be used to study stability properties of field-theoretical solitons. We demonstrate, e.g., the formation of a half-quantum vortex arch, an Alice arch, on the interface, exhibiting the topological charge of a point defect. We also demonstrate an energetically stable connection of a coreless vortex to two half-quantum vortices. Our method can be extended to study interface physics in spin-2 and spin-3 BECs with richer phenomenology, or in strongly correlated optical-lattice systems. We acknowledge financial support from the Leverhulme Trust.
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De Mauro, Alessandro; Carrasco, Eduardo; Oyarzun, David; Ardanza, Aitor; Frizera Neto, Anselmo; Torricelli, Diego; Pons, José Luis; Gil, Angel; Florez, Julian
2011-01-01
Cerebrovascular accidents (CVA) and spinal cord injuries (SCI) are the most common causes of paralysis and paresis with reported prevalence of 12,000 cases per million and 800 cases per million, respectively. Disabilities that follow CVA (hemiplegia) or SCI (paraplegia, tetraplegia) severely impair motor functions (e.g., standing, walking, reaching and grasping) and prevent the affected individuals from healthy-like, full and autonomous participation in daily activities. Our research focuses on the development of a new virtual reality (VR) system combined with wearable neurorobotics (NR), motor-neuroprosthetics (MNP) and brain neuro-machine interface (BNMI) to overcome the major limitations of current rehabilitation solutions.
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NASA Astrophysics Data System (ADS)
Srivastava, Amar; Saha, S.; Annadi, A.; Zhao, Y. L.; Gopinadhan, K.; Wang, X.; Naomi, N.; Liu, Z. Q.; Dhar, S.; Herng, T. S.; Nina, Bao; Ariando, -; Ding, Jun; Venkatesan, T.
2012-02-01
In this work we report a study of a coherently coupled interface consisting of a ZnO layer grown on top of an oriented VO2 layer on sapphire by photoluminescence and electrical transport measurements across the VO2 metal insulator phase transition (MIT). The photoluminescence of the ZnO layer showed a broad hysteresis induced by the phase transition of VO2 while the width of the electrical hysteresis was narrow and unaffected by the over layer. The enhanced width of the PL hysteresis was due to the formation of defects during the MIT as evidenced by a broad hysteresis in the opposite direction to that of the band edge PL in the defect luminescense. Unlike VO2 the defects in ZnO did not fully recover across the phase transition. From the defect luminescence data, oxygen interstitials were found to be the predominant defects in ZnO mediated by the strain from the VO2 phase transition. Such coherently coupled interfaces could be of use in characterizing the stability of a variety of interfaces and also for novel device application.
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Automated Geospatial Watershed Assessment Tool (AGWA)
USDA-ARS?s Scientific Manuscript database
The Automated Geospatial Watershed Assessment tool (AGWA, see: www.tucson.ars.ag.gov/agwa or http://www.epa.gov/esd/land-sci/agwa/) is a GIS interface jointly developed by the USDA Agricultural Research Service, the U.S. Environmental Protection Agency, the University of Arizona, and the University ...
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An Overview of CC Coherent Pion Production
NASA Astrophysics Data System (ADS)
Williams, Zachary
2017-01-01
Neutrino cross-sections are a critical component to any neutrino measurement. With the modern neutrino experiments aiming to measure precision parameters, such as those in long-baseline oscillation experiments, the need for a detailed understanding of neutrino interactions has become even more important. Within this landscape remains a number of experimental challenges in the regime of low energy neutrino cross-sections. This talk will give an overview of recent publications on Charged Current-Coherent Pion Production (CC-Coh Pion) results from a number of experimental collaborations. Specifically, the lack of observation from the SciBooNE and T2K collaborations to observe CC-Coh Pion below one GeV in contrast to the observation of this signature at higher energies by other experiments. The work presented here is a part of the beginning steps to a reanalysis of the SciBooNE data using a modern neutrino generator in order to better understand the previous results. There will be included details of a liquid Argon purification system that is being built at UTA, and of plans for a ``Baby Time Projection Chamber (TPC)'' which will also be built at UTA, and the instrumentation and detector methods used in their construction. The closing is a look to the future for a new analysis at low neutrino energies utilizing Liquid Argon Time Projection Chambers (LArTPCs) based at Fermilab.
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Comfort evaluation of a subject-specific seating interface formed by vibrating grains.
Liu, Shenghui; Qu, Yunxia; Hou, Shujun; Li, Kai; Li, Xinye; Zhai, Yang; Ji, Yunxiao
2018-09-01
Sitting is the most common posture for work in offices, and spinal cord injury (SCI) patients who are wheelchair dependent spend 10.6 h per day seated in wheelchairs. Thus, the comfort of subject-specific interfaces is increasingly important for the well-being of patients and office workers. This paper introduces a new method of forming a subject-specific interface, based on vibrating grains. Twenty subjects (10 females and 10 males) participated in the sitting test. Interface comfort was evaluated using the pressure distribution and subjective rating methods. Five seating interface types were compared. The results showed that compared with a flat interface, the interfaces formed by vibrating grains had a significantly reduced peak contact pressure (PeakCP) (by more than 58.03%), and that PeakCP was highly correlated with the comfort rating (R = -0.533) and discomfort rating(R = -0.603). This new method shows promise for guiding the future development of customized seating interfaces. Copyright © 2018 Elsevier Ltd. All rights reserved.
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SciSpark's SRDD : A Scientific Resilient Distributed Dataset for Multidimensional Data
NASA Astrophysics Data System (ADS)
Palamuttam, R. S.; Wilson, B. D.; Mogrovejo, R. M.; Whitehall, K. D.; Mattmann, C. A.; McGibbney, L. J.; Ramirez, P.
2015-12-01
Remote sensing data and climate model output are multi-dimensional arrays of massive sizes locked away in heterogeneous file formats (HDF5/4, NetCDF 3/4) and metadata models (HDF-EOS, CF) making it difficult to perform multi-stage, iterative science processing since each stage requires writing and reading data to and from disk. We have developed SciSpark, a robust Big Data framework, that extends ApacheTM Spark for scaling scientific computations. Apache Spark improves the map-reduce implementation in ApacheTM Hadoop for parallel computing on a cluster, by emphasizing in-memory computation, "spilling" to disk only as needed, and relying on lazy evaluation. Central to Spark is the Resilient Distributed Dataset (RDD), an in-memory distributed data structure that extends the functional paradigm provided by the Scala programming language. However, RDDs are ideal for tabular or unstructured data, and not for highly dimensional data. The SciSpark project introduces the Scientific Resilient Distributed Dataset (sRDD), a distributed-computing array structure which supports iterative scientific algorithms for multidimensional data. SciSpark processes data stored in NetCDF and HDF files by partitioning them across time or space and distributing the partitions among a cluster of compute nodes. We show usability and extensibility of SciSpark by implementing distributed algorithms for geospatial operations on large collections of multi-dimensional grids. In particular we address the problem of scaling an automated method for finding Mesoscale Convective Complexes. SciSpark provides a tensor interface to support the pluggability of different matrix libraries. We evaluate performance of the various matrix libraries in distributed pipelines, such as Nd4jTM and BreezeTM. We detail the architecture and design of SciSpark, our efforts to integrate climate science algorithms, parallel ingest and partitioning (sharding) of A-Train satellite observations from model grids. These solutions are encompassed in SciSpark, an open-source software framework for distributed computing on scientific data.
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A Hele-Shaw-Cahn-Hilliard Model for Incompressible Two-Phase Flows with Different Densities
NASA Astrophysics Data System (ADS)
Dedè, Luca; Garcke, Harald; Lam, Kei Fong
2017-07-01
Topology changes in multi-phase fluid flows are difficult to model within a traditional sharp interface theory. Diffuse interface models turn out to be an attractive alternative to model two-phase flows. Based on a Cahn-Hilliard-Navier-Stokes model introduced by Abels et al. (Math Models Methods Appl Sci 22(3):1150013, 2012), which uses a volume-averaged velocity, we derive a diffuse interface model in a Hele-Shaw geometry, which in the case of non-matched densities, simplifies an earlier model of Lee et al. (Phys Fluids 14(2):514-545, 2002). We recover the classical Hele-Shaw model as a sharp interface limit of the diffuse interface model. Furthermore, we show the existence of weak solutions and present several numerical computations including situations with rising bubbles and fingering instabilities.
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Studies of electrode structures and dynamics using coherent X-ray scattering and imaging
DOE Office of Scientific and Technical Information (OSTI.GOV)
You, H.; Liu, Y.; Ulvestad, A.
2017-08-01
Electrochemical systems studied in situ with advanced surface X-ray scattering techniques are reviewed. The electrochemical systems covered include interfaces of single-crystals and nanocrystals with respect to surface modification, aqueous dissolution, surface reconstruction, and electrochemical double layers. An emphasis will be given on recent results by coherent X-ray techniques such as X-ray photon correlation spectroscopy, Bragg coherent diffraction imaging, and surface ptychography.
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NASA Astrophysics Data System (ADS)
Wilson, B. D.; Manipon, G.; Xing, Z.
2007-12-01
The General Earth Science Investigation Suite (GENESIS) project is a NASA-sponsored partnership between the Jet Propulsion Laboratory, academia, and NASA data centers to develop a new suite of Web Services tools to facilitate multi-sensor investigations in Earth System Science. The goal of GENESIS is to enable large-scale, multi-instrument atmospheric science using combined datasets from the AIRS, MODIS, MISR, and GPS sensors. Investigations include cross-comparison of spaceborne climate sensors, cloud spectral analysis, study of upper troposphere-stratosphere water transport, study of the aerosol indirect cloud effect, and global climate model validation. The challenges are to bring together very large datasets, reformat and understand the individual instrument retrievals, co-register or re-grid the retrieved physical parameters, perform computationally-intensive data fusion and data mining operations, and accumulate complex statistics over months to years of data. To meet these challenges, we have developed a Grid computing and dataflow framework, named SciFlo, in which we are deploying a set of versatile and reusable operators for data access, subsetting, registration, mining, fusion, compression, and advanced statistical analysis. SciFlo leverages remote Web Services, called via Simple Object Access Protocol (SOAP) or REST (one-line) URLs, and the Grid Computing standards (WS-* & Globus Alliance toolkits), and enables scientists to do multi- instrument Earth Science by assembling reusable Web Services and native executables into a distributed computing flow (tree of operators). The SciFlo client & server engines optimize the execution of such distributed data flows and allow the user to transparently find and use datasets and operators without worrying about the actual location of the Grid resources. In particular, SciFlo exploits the wealth of datasets accessible by OpenGIS Consortium (OGC) Web Mapping Servers & Web Coverage Servers (WMS/WCS), and by Open Data Access Protocol (OpenDAP) servers. SciFlo also publishes its own SOAP services for space/time query and subsetting of Earth Science datasets, and automated access to large datasets via lists of (FTP, HTTP, or DAP) URLs which point to on-line HDF or netCDF files. Typical distributed workflows obtain datasets by calling standard WMS/WCS servers or discovering and fetching data granules from ftp sites; invoke remote analysis operators available as SOAP services (interface described by a WSDL document); and merge results into binary containers (netCDF or HDF files) for further analysis using local executable operators. Naming conventions (HDFEOS and CF-1.0 for netCDF) are exploited to automatically understand and read on-line datasets. More interoperable conventions, and broader adoption of existing converntions, are vital if we are to "scale up" automated choreography of Web Services beyond toy applications. Recently, the ESIP Federation sponsored a collaborative activity in which several ESIP members developed some collaborative science scenarios for atmospheric and aerosol science, and then choreographed services from multiple groups into demonstration workflows using the SciFlo engine and a Business Process Execution Language (BPEL) workflow engine. We will discuss the lessons learned from this activity, the need for standardized interfaces (like WMS/WCS), the difficulty in agreeing on even simple XML formats and interfaces, the benefits of doing collaborative science analysis at the "touch of a button" once services are connected, and further collaborations that are being pursued.
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1982-03-01
observed coherent structure of the wall layer flow and will now be briefly described. Over the past decade, it has been well documented (see, for example...D2, and x are all arbitrary constants. Equilibrium flows have been examined experimentally for a number of years and an equilibrium boundary layer...CP93, Paper No. 27, 6. Clauser, F.H. (1954). "Turbulent Boundary Layers in Adverse Pressure Gradients", J. Aeronaut. Sci., 21, pp. 91-108. 7. Clauser
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2011-01-01
Sands T, Xu X, Fisher T. Dendrimer -assisted controlled growth of carbon nanotubes for enhanced thermal interface conductance. Nanotechnology 2007;18...surfaces. Rev Sci Instrum 2006;77(9):095105-1–3. [11] Allaoui A, Hoa S, Evesque P, Bai J. Electronic transport in carbon nanotube tangles under compression
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New tools and functionality have been incorporated into the Automated Geospatial Watershed Assessment Tool (AGWA) to assess the impacts of wildland fire on runoff and erosion. AGWA (see: www.tucson.ars.ag.gov/agwa or http://www.epa.gov/esd/land-sci/agwa/) is a GIS interface joi...
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The Automated Geospatial Watershed Assessment (http://www.epa.gov/nerlesd1/land-sci/agwa/introduction.htm and www.tucson.ars.ag.gov/agwa) tool is a GIS interface jointly developed by the U.S. Environmental Protection Agency, USDA-Agricultural Research Service, and the University ...
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Influence of GaAs surface termination on GaSb/GaAs quantum dot structure and band offsets
DOE Office of Scientific and Technical Information (OSTI.GOV)
Zech, E. S.; Chang, A. S.; Martin, A. J.
2013-08-19
We have investigated the influence of GaAs surface termination on the nanoscale structure and band offsets of GaSb/GaAs quantum dots (QDs) grown by molecular-beam epitaxy. Transmission electron microscopy reveals both coherent and semi-coherent clusters, as well as misfit dislocations, independent of surface termination. Cross-sectional scanning tunneling microscopy and spectroscopy reveal clustered GaSb QDs with type I band offsets at the GaSb/GaAs interfaces. We discuss the relative influences of strain and QD clustering on the band offsets at GaSb/GaAs interfaces.
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Coherent frequency bridge between visible and telecommunications band for vortex light.
Liu, Shi-Long; Liu, Shi-Kai; Li, Yin-Hai; Shi, Shuai; Zhou, Zhi-Yuan; Shi, Bao-Sen
2017-10-02
In quantum communications, vortex photons can encode higher-dimensional quantum states and build high-dimensional communication networks (HDCNs). The interfaces that connect different wavelengths are significant in HDCNs. We construct a coherent orbital angular momentum (OAM) frequency bridge via difference frequency conversion in a nonlinear bulk crystal for HDCNs. Using a single resonant cavity, maximum quantum conversion efficiencies from visible to infrared are 36%, 15%, and 7.8% for topological charges of 0,1, and 2, respectively. The average fidelity obtained using quantum state tomography for the down-converted infrared OAM-state of topological charge 1 is 96.51%. We also prove that the OAM is conserved in this process by measuring visible and infrared interference patterns. This coherent OAM frequency-down conversion bridge represents a basis for an interface between two high-dimensional quantum systems operating with different spectra.
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NASA Technical Reports Server (NTRS)
Howlett, J. T.
1979-01-01
The partial coherence analysis method for noise source/path determination is summarized and the application to a two input, single output system with coherence between the inputs is illustrated. The augmentation of the calculations on a digital computer interfaced with a two channel, real time analyzer is also discussed. The results indicate possible sources of error in the computations and suggest procedures for avoiding these errors.
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A new version of Scilab software package for the study of dynamical systems
NASA Astrophysics Data System (ADS)
Bordeianu, C. C.; Felea, D.; Beşliu, C.; Jipa, Al.; Grossu, I. V.
2009-11-01
This work presents a new version of a software package for the study of chaotic flows, maps and fractals [1]. The codes were written using Scilab, a software package for numerical computations providing a powerful open computing environment for engineering and scientific applications. It was found that Scilab provides various functions for ordinary differential equation solving, Fast Fourier Transform, autocorrelation, and excellent 2D and 3D graphical capabilities. The chaotic behaviors of the nonlinear dynamics systems were analyzed using phase-space maps, autocorrelation functions, power spectra, Lyapunov exponents and Kolmogorov-Sinai entropy. Various well-known examples are implemented, with the capability of the users inserting their own ODE or iterative equations. New version program summaryProgram title: Chaos v2.0 Catalogue identifier: AEAP_v2_0 Program summary URL:
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Body machine interfaces for neuromotor rehabilitation: a case study.
Pierella, Camilla; Abdollahi, Farnaz; Farshchiansadegh, Ali; Pedersen, Jessica; Chen, David; Mussa-Ivaldi, Ferdinando A; Casadio, Maura
2014-01-01
High-level spinal cord injury (SCI) survivors face every day two related problems: recovering motor skills and regaining functional independence. Body machine interfaces (BoMIs) empower people with sever motor disabilities with the ability to control an external device, but they also offer the opportunity to focus concurrently on achieving rehabilitative goals. In this study we developed a portable, and low-cost BoMI that addresses both problems. The BoMI remaps the user's residual upper body mobility to the two coordinates of a cursor on a computer monitor. By controlling the cursor, the user can perform functional tasks, such as entering text and playing games. This framework also allows the mapping between the body and the cursor space to be modified, gradually challenging the user to exercise more impaired movements. With this approach, we were able to change the behavior of our SCI subject, who initially used almost exclusively his less impaired degrees of freedom - on the left side - for controlling the BoMI. At the end of the few practice sessions he had restored symmetry between left and right side of the body, with an increase of mobility and strength of all the degrees of freedom involved in the control of the interface. This is the first proof of concept that our BoMI can be used to control assistive devices and reach specific rehabilitative goals simultaneously.
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Lenton, Pat; Rudney, Joel; Chen, Ruoqiong; Fok, Alex; Aparicio, Conrado; Jones, Robert S.
2012-01-01
Objectives Conventional diagnostic methods frequently detect only late stage enamel demineralization under composite resin restorations. The objective of this study is to examine the subsurface tooth-composite interface and to assess for the presence of secondary caries in pediatric patients using a novel Optical Coherence Tomography System with an intraoral probe. Methods A newly designed intraoral cross polarization swept source optical coherence tomography (CP-OCT) imaging system was used to examine the integrity of the enamel-composite interfaces in vivo. Twenty two pediatric subjects were recruited with either recently placed or long standing composite restorations in their primary teeth. To better understand how bacterial biofilms cause demineralization at the interface, we also used the intraoral CP-OCT system to assess ex vivo bacterial biofilm growth on dental composites. Results As a positive control, cavitated secondary carious interfaces showed a 18.2 dB increase (p<0.001), or over 1-2 orders of magnitude higher, scattering than interfaces associated with recently placed composite restorations. Several long standing composite restorations, which appeared clinically sound, had a marked increase in scattering than recently placed restorations. This suggests the ability of CP-OCT to assess interfacial degradation such as early secondary caries prior to cavitation. CP-OCT was also able to image ex vivo biofilms on dental composites and assess their thickness. Significance This paper shows that CP-OCT imaging using a beam splitter based design can examine the subsurface interface of dental composites in human subjects. Furthermore, the probe dimensions and acquisition speed of the CP-OCT system allowed for analysis of caries development in children. PMID:22578989
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Khalid, Umer; Conti, Gerry E; Erlandson, Robert F; Ellis, Richard D; Brown, Vince; Pandya, Abhilash K
2015-01-01
The focus of this research was to design a functional and user-friendly reacher for people with spinal cord injuries (SCIs). Engineering advancements have taken assistive robotics to new dimensions. Technologies such as wheelchair robotics and myo-electronically controlled systems have opened up a wide range of new applications to assist people with physical disabilities. Similarly, exo-skeletal limbs and body suits have provided new foundations from which technologies can aid function. Unfortunately, these devices have issues of usability, weight, and discomfort with donning. The Smart Assistive Reacher Arm (SARA) system, developed in this research, is a voice-activated, lightweight, mobile device that can be used when needed. SARA was built to help overcome daily reach challenges faced by individuals with limited arm and hand movement capability, such as people with cervical level 5-6 (C5-6) SCI. This article shows that a functional reacher arm with voice control can be beneficial for this population. Comparison study with healthy participants and an SCI participant shows that, when using SARA, a person with SCI can perform simple reach and grasp tasks independently, without someone else's help. This suggests that the interface is intuitive and can be easily used to a high level of proficiency by a SCI individual.
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Eaton, Rebecca; Jones, Kevin; Duff, Jane
2018-06-12
Retrospective, cross-sectional study. To investigate the factor structure of the ADAPSS-short form (ADAPSS-SF) in an acutely injured SCI population and to assess the relationship between cognitive appraisals made in the initial phase of rehabilitation and the experience of anxiety and depression. National Spinal Injuries Centre, UK. Participants were acutely injured patients admitted to the NSIC over 35 months. Cognitive appraisals were measured using the ADAPSS-SF; psychological distress was measured using the HADS. Individual profiles, including demographics and injury characteristics, were collected. Principle Component Analysis with oblique rotation demonstrated a coherent two-factor structure of the ADAPSS-SF: resilience and loss. Correlational analysis found that individuals who negatively appraised their injury were more likely to report lower mood. Findings identified four vulnerable subgroups that were more likely to negatively appraise their injury: females, individuals older at the time of SCI, individuals with AIS-A injuries and individuals whose SCI was acquired through assault. Hierarchical regression analysis reported that resilience and loss factors were significant predictors of depression. Gender, resilience and loss factors were significant predictors of anxiety. Cognitive appraisals accounted for more variance in mood above biological markers. Findings support a two-factor structure and validity of ADAPSS-SF in acute SCI rehabilitation. The study provides support for the role of cognitive appraisals in psychological adjustment in the early phases of rehabilitation, above injury characteristics. Findings highlighted the vulnerable subgroups that are more likely to initially endorse negative appraisals, which may influence clinical practice and provides an avenue for further research.
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ERIC Educational Resources Information Center
Bharti, Neelam; Leonard, Michelle; Singh, Shailendra
2016-01-01
Online chemical databases are the largest source of chemical information and, therefore, the main resource for retrieving results from published journals, books, patents, conference abstracts, and other relevant sources. Various commercial, as well as free, chemical databases are available. SciFinder, Reaxys, and Web of Science are three major…
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Photoemission from buried interfaces in SrTiO3/LaTiO3 superlattices.
Takizawa, M; Wadati, H; Tanaka, K; Hashimoto, M; Yoshida, T; Fujimori, A; Chikamatsu, A; Kumigashira, H; Oshima, M; Shibuya, K; Mihara, T; Ohnishi, T; Lippmaa, M; Kawasaki, M; Koinuma, H; Okamoto, S; Millis, A J
2006-08-04
We have measured photoemission spectra of SrTiO3/LaTiO3 superlattices with a topmost SrTiO3 layer of variable thickness. A finite coherent spectral weight with a clear Fermi cutoff was observed at chemically abrupt SrTiO3/LaTiO3 interfaces, indicating that an "electronic reconstruction" occurs at the interface between the Mott insulator LaTiO3 and the band insulator SrTiO3. For SrTiO3/LaTiO3 interfaces annealed at high temperatures (approximately 1000 degrees C), which leads to Sr/La atomic interdiffusion and hence to the formation of La(1-x)Sr(x)TiO3-like material, the intensity of the incoherent part was found to be dramatically reduced whereas the coherent part with a sharp Fermi cutoff was enhanced due to the spread of charge. These important experimental features are well reproduced by layer dynamical-mean-field-theory calculation.
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Systems and technologies for high-speed inter-office/datacenter interface
NASA Astrophysics Data System (ADS)
Sone, Y.; Nishizawa, H.; Yamamoto, S.; Fukutoku, M.; Yoshimatsu, T.
2017-01-01
Emerging requirements for inter-office/inter-datacenter short reach links for data center interconnects (DCI) and metro transport networks have led to various inter-office and inter-datacenter optical interface technologies. These technologies are bringing significant changes to systems and network architectures. In this paper, we present a system and ZR optical interface technologies for DCI and metro transport networks, then introduce the latest challenges facing the system framework. There are two trends in reach extension; one is to use Ethernet and the other is to use digital coherent technologies. The first approach achieves reach extension while using as many existing Ethernet components as possible. It offers low costs as reuses the cost-effective components created for the large Ethernet market. The second approach adopts low-cost and low power coherent DSPs that implement the minimal set long haul transmission functions. This paper introduces an architecture that integrates both trends. The architecture satisfies both datacom and telecom needs with a common control and management interface and automated configuration.
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Interfaces detection after corneal refractive surgery by low coherence optical interferometry
Verrier, I.; Veillas, C.; Lépine, T.; Nguyen, F.; Thuret, G.; Gain, P.
2010-01-01
The detection of refractive corneal surgery by LASIK, during the storage of corneas in Eye Banks will become a challenge when the numerous operated patients will arrive at the age of cornea donation. The subtle changes of corneal structure and refraction are highly suspected to negatively influence clinical results in recipients of such corneas. In order to detect LASIK cornea interfaces we developed a low coherence interferometry technique using a broadband continuum source. Real time signal recording, without moving any optical elements and without need of a Fourier Transform operation, combined with good measurement resolution is the main asset of this interferometer. The associated numerical processing is based on a method initially used in astronomy and offers an optimal correlation signal without the necessity to image the whole cornea that is time consuming. The detection of corneal interfaces - both outer and inner surface and the buried interface corresponding to the surgical wound – is then achieved directly by the innovative combination of interferometry and this original numerical process. PMID:21258562
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On the mobility of carriers at semi-coherent oxide heterointerfaces
DOE Office of Scientific and Technical Information (OSTI.GOV)
Dholabhai, Pratik P.; Martinez, Enrique Saez; Brown, Nicholas Taylor
In the quest to develop new materials with enhanced ionic conductivity for battery and fuel cell applications, nano-structured oxides have attracted attention. Experimental reports indicate that oxide heterointerfaces can lead to enhanced ionic conductivity, but these same reports cannot elucidate the origin of this enhancement, often vaguely referring to pipe diffusion at misfit dislocations as a potential explanation. However, this highlights the need to understand the role of misfit dislocation structure at semi-coherent oxide heterointerfaces in modifying carrier mobilities. Here, we use atomistic and kinetic Monte Carlo (KMC) simulations to develop a model of oxygen vacancy migration at SrTiO 3/MgOmore » interfaces, chosen because the misfit dislocation structure can be modified by changing the termination chemistry. We use atomistic simulations to determine the energetics of oxygen vacancies at both SrO and TiO 2 terminated interfaces, which are then used as the basis of the KMC simulations. While this model is approximate (as revealed by select nudged elastic band calculations), it highlights the role of the misfit dislocation structure in modifying the oxygen vacancy dynamics. We find that oxygen vacancy mobility is significantly reduced at either interface, with slight differences at each interface due to the differing misfit dislocation structure. Here, we conclude that if such semi-coherent oxide heterointerfaces induce enhanced ionic conductivity, it is not a consequence of higher carrier mobility.« less
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On the mobility of carriers at semi-coherent oxide heterointerfaces
Dholabhai, Pratik P.; Martinez, Enrique Saez; Brown, Nicholas Taylor; ...
2017-08-17
In the quest to develop new materials with enhanced ionic conductivity for battery and fuel cell applications, nano-structured oxides have attracted attention. Experimental reports indicate that oxide heterointerfaces can lead to enhanced ionic conductivity, but these same reports cannot elucidate the origin of this enhancement, often vaguely referring to pipe diffusion at misfit dislocations as a potential explanation. However, this highlights the need to understand the role of misfit dislocation structure at semi-coherent oxide heterointerfaces in modifying carrier mobilities. Here, we use atomistic and kinetic Monte Carlo (KMC) simulations to develop a model of oxygen vacancy migration at SrTiO 3/MgOmore » interfaces, chosen because the misfit dislocation structure can be modified by changing the termination chemistry. We use atomistic simulations to determine the energetics of oxygen vacancies at both SrO and TiO 2 terminated interfaces, which are then used as the basis of the KMC simulations. While this model is approximate (as revealed by select nudged elastic band calculations), it highlights the role of the misfit dislocation structure in modifying the oxygen vacancy dynamics. We find that oxygen vacancy mobility is significantly reduced at either interface, with slight differences at each interface due to the differing misfit dislocation structure. Here, we conclude that if such semi-coherent oxide heterointerfaces induce enhanced ionic conductivity, it is not a consequence of higher carrier mobility.« less
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Optical to optical interface device
NASA Technical Reports Server (NTRS)
Oliver, D. S.; Vohl, P.; Nisenson, P.
1972-01-01
The development, fabrication, and testing of a preliminary model of an optical-to-optical (noncoherent-to-coherent) interface device for use in coherent optical parallel processing systems are described. The developed device demonstrates a capability for accepting as an input a scene illuminated by a noncoherent radiation source and providing as an output a coherent light beam spatially modulated to represent the original noncoherent scene. The converter device developed under this contract employs a Pockels readout optical modulator (PROM). This is a photosensitive electro-optic element which can sense and electrostatically store optical images. The stored images can be simultaneously or subsequently readout optically by utilizing the electrostatic storage pattern to control an electro-optic light modulating property of the PROM. The readout process is parallel as no scanning mechanism is required. The PROM provides the functions of optical image sensing, modulation, and storage in a single active material.
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NASA Astrophysics Data System (ADS)
Romînu, Roxana Otilia; Sinescu, Cosmin; Romînu, Mihai; Negrutiu, Meda; Laissue, Philippe; Mihali, Sorin; Cuc, Lavinia; Hughes, Michael; Bradu, Adrian; Podoleanu, Adrian
2008-09-01
Bonding has become a routine procedure in several dental specialties - from prosthodontics to conservative dentistry and even orthodontics. In many of these fields it is important to be able to investigate the bonded interfaces to assess their quality. All currently employed investigative methods are invasive, meaning that samples are destroyed in the testing procedure and cannot be used again. We have investigated the interface between human enamel and bonded ceramic brackets non-invasively, introducing a combination of new investigative methods - optical coherence tomography (OCT) and confocal microscopy (CM). Brackets were conventionally bonded on conditioned buccal surfaces of teeth The bonding was assessed using these methods. Three dimensional reconstructions of the detected material defects were developed using manual and semi-automatic segmentation. The results clearly prove that OCT and CM are useful in orthodontic bonding investigations.
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Operation of a brain-computer interface walking simulator for individuals with spinal cord injury
2013-01-01
Background Spinal cord injury (SCI) can leave the affected individuals with paraparesis or paraplegia, thus rendering them unable to ambulate. Since there are currently no restorative treatments for this population, novel approaches such as brain-controlled prostheses have been sought. Our recent studies show that a brain-computer interface (BCI) can be used to control ambulation within a virtual reality environment (VRE), suggesting that a BCI-controlled lower extremity prosthesis for ambulation may be feasible. However, the operability of our BCI has not yet been tested in a SCI population. Methods Five participants with paraplegia or tetraplegia due to SCI underwent a 10-min training session in which they alternated between kinesthetic motor imagery (KMI) of idling and walking while their electroencephalogram (EEG) were recorded. Participants then performed a goal-oriented online task, where they utilized KMI to control the linear ambulation of an avatar while making 10 sequential stops at designated points within the VRE. Multiple online trials were performed in a single day, and this procedure was repeated across 5 experimental days. Results Classification accuracy of idling and walking was estimated offline and ranged from 60.5% (p = 0.0176) to 92.3% (p = 1.36×10−20) across participants and days. Offline analysis revealed that the activation of mid-frontal areas mostly in the μ and low β bands was the most consistent feature for differentiating between idling and walking KMI. In the online task, participants achieved an average performance of 7.4±2.3 successful stops in 273±51 sec. These performances were purposeful, i.e. significantly different from the random walk Monte Carlo simulations (p<0.01), and all but one participant achieved purposeful control within the first day of the experiments. Finally, all participants were able to maintain purposeful control throughout the study, and their online performances improved over time. Conclusions The results of this study demonstrate that SCI participants can purposefully operate a self-paced BCI walking simulator to complete a goal-oriented ambulation task. The operation of the proposed BCI system requires short training, is intuitive, and robust against participant-to-participant and day-to-day neurophysiological variations. These findings indicate that BCI-controlled lower extremity prostheses for gait rehabilitation or restoration after SCI may be feasible in the future. PMID:23866985
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Three-dimensional ophthalmic optical coherence tomography with a refraction correction algorithm
NASA Astrophysics Data System (ADS)
Zawadzki, Robert J.; Leisser, Christoph; Leitgeb, Rainer; Pircher, Michael; Fercher, Adolf F.
2003-10-01
We built an optical coherence tomography (OCT) system with a rapid scanning optical delay (RSOD) line, which allows probing full axial eye length. The system produces Three-dimensional (3D) data sets that are used to generate 3D tomograms of the model eye. The raw tomographic data were processed by an algorithm, which is based on Snell"s law to correct the interface positions. The Zernike polynomials representation of the interfaces allows quantitative wave aberration measurements. 3D images of our results are presented to illustrate the capabilities of the system and the algorithm performance. The system allows us to measure intra-ocular distances.
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Crossover from Incoherent to Coherent Phonon Scattering in Epitaxial Oxide Superlattices
2013-12-08
function of interface density. We do so by synthesizing superlattices of electrically insulating perovskite oxides 1. REPORT DATE (DD-MM-YYYY) 4. TITLE...synthesizing superlattices of electrically insulating perovskite oxides and systematically varying the interface density, with unit-cell precision, using two...a function of interface density. Wedo so by synthesizing superlattices of electrically insulating perovskite oxides and systematically varying the
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Storing quantum information for 30 seconds in a nanoelectronic device.
Muhonen, Juha T; Dehollain, Juan P; Laucht, Arne; Hudson, Fay E; Kalra, Rachpon; Sekiguchi, Takeharu; Itoh, Kohei M; Jamieson, David N; McCallum, Jeffrey C; Dzurak, Andrew S; Morello, Andrea
2014-12-01
The spin of an electron or a nucleus in a semiconductor naturally implements the unit of quantum information--the qubit. In addition, because semiconductors are currently used in the electronics industry, developing qubits in semiconductors would be a promising route to realize scalable quantum information devices. The solid-state environment, however, may provide deleterious interactions between the qubit and the nuclear spins of surrounding atoms, or charge and spin fluctuations arising from defects in oxides and interfaces. For materials such as silicon, enrichment of the spin-zero (28)Si isotope drastically reduces spin-bath decoherence. Experiments on bulk spin ensembles in (28)Si crystals have indeed demonstrated extraordinary coherence times. However, it remained unclear whether these would persist at the single-spin level, in gated nanostructures near amorphous interfaces. Here, we present the coherent operation of individual (31)P electron and nuclear spin qubits in a top-gated nanostructure, fabricated on an isotopically engineered (28)Si substrate. The (31)P nuclear spin sets the new benchmark coherence time (>30 s with Carr-Purcell-Meiboom-Gill (CPMG) sequence) of any single qubit in the solid state and reaches >99.99% control fidelity. The electron spin CPMG coherence time exceeds 0.5 s, and detailed noise spectroscopy indicates that--contrary to widespread belief--it is not limited by the proximity to an interface. Instead, decoherence is probably dominated by thermal and magnetic noise external to the device, and is thus amenable to further improvement.
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Collaborative Science Using Web Services and the SciFlo Grid Dataflow Engine
NASA Astrophysics Data System (ADS)
Wilson, B. D.; Manipon, G.; Xing, Z.; Yunck, T.
2006-12-01
The General Earth Science Investigation Suite (GENESIS) project is a NASA-sponsored partnership between the Jet Propulsion Laboratory, academia, and NASA data centers to develop a new suite of Web Services tools to facilitate multi-sensor investigations in Earth System Science. The goal of GENESIS is to enable large-scale, multi-instrument atmospheric science using combined datasets from the AIRS, MODIS, MISR, and GPS sensors. Investigations include cross-comparison of spaceborne climate sensors, cloud spectral analysis, study of upper troposphere-stratosphere water transport, study of the aerosol indirect cloud effect, and global climate model validation. The challenges are to bring together very large datasets, reformat and understand the individual instrument retrievals, co-register or re-grid the retrieved physical parameters, perform computationally-intensive data fusion and data mining operations, and accumulate complex statistics over months to years of data. To meet these challenges, we have developed a Grid computing and dataflow framework, named SciFlo, in which we are deploying a set of versatile and reusable operators for data access, subsetting, registration, mining, fusion, compression, and advanced statistical analysis. SciFlo leverages remote Web Services, called via Simple Object Access Protocol (SOAP) or REST (one-line) URLs, and the Grid Computing standards (WS-* &Globus Alliance toolkits), and enables scientists to do multi-instrument Earth Science by assembling reusable Web Services and native executables into a distributed computing flow (tree of operators). The SciFlo client &server engines optimize the execution of such distributed data flows and allow the user to transparently find and use datasets and operators without worrying about the actual location of the Grid resources. In particular, SciFlo exploits the wealth of datasets accessible by OpenGIS Consortium (OGC) Web Mapping Servers & Web Coverage Servers (WMS/WCS), and by Open Data Access Protocol (OpenDAP) servers. The scientist injects a distributed computation into the Grid by simply filling out an HTML form or directly authoring the underlying XML dataflow document, and results are returned directly to the scientist's desktop. Once an analysis has been specified for a chunk or day of data, it can be easily repeated with different control parameters or over months of data. Recently, the Earth Science Information Partners (ESIP) Federation sponsored a collaborative activity in which several ESIP members advertised their respective WMS/WCS and SOAP services, developed some collaborative science scenarios for atmospheric and aerosol science, and then choreographed services from multiple groups into demonstration workflows using the SciFlo engine and a Business Process Execution Language (BPEL) workflow engine. For several scenarios, the same collaborative workflow was executed in three ways: using hand-coded scripts, by executing a SciFlo document, and by executing a BPEL workflow document. We will discuss the lessons learned from this activity, the need for standardized interfaces (like WMS/WCS), the difficulty in agreeing on even simple XML formats and interfaces, and further collaborations that are being pursued.
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PanMetaDocs - A tool for collecting and managing the long tail of "small science data"
NASA Astrophysics Data System (ADS)
Klump, J.; Ulbricht, D.
2011-12-01
In the early days of thinking about cyberinfrastructure the focus was on "big science data". Today, the challenge is not anymore to store several terabytes of data, but to manage data objects in a way that facilitates their re-use. Key to re-use by a user as a data consumer is proper documentation of the data. Also, data consumers need discovery metadata to find the data they need and they need descriptive metadata to be able to use the data they retrieved. Thus, data documentation faces the challenge to extensively and completely describe these objects, hold the items easily accessible at a sustainable cost level. However, data curation and documentation do not rank high in the everyday work of a scientist as a data producer. Data producers are often frustrated by being asked to provide metadata on their data over and over again, information that seemed very obvious from the context of their work. A challenge to data archives is the wide variety of metadata schemata in use, which creates a number of maintenance and design challenges of its own. PanMetaDocs addresses these issues by allowing an uploaded files to be described by more than one metadata object. PanMetaDocs, which was developed from PanMetaWorks, is a PHP based web application that allow to describe data with any xml-based metadata schema. Its user interface is browser based and was developed to collect metadata and data in collaborative scientific projects situated at one or more institutions. The metadata fields can be filled with static or dynamic content to reduce the number of fields that require manual entries to a minimum and make use of contextual information in a project setting. In the development of PanMetaDocs the business logic of panMetaWorks is reused, except for the authentication and data management functions of PanMetaWorks, which are delegated to the eSciDoc framework. The eSciDoc repository framework is designed as a service oriented architecture that can be controlled through a REST interface to create version controlled items with metadata records in XML format. PanMetaDocs utilizes the eSciDoc items model to add multiple metadata records that describe uploaded files in different metadata schemata. While datasets are collected and described, shared to collaborate with other scientists and finally published, data objects are transferred from a shared data curation domain into a persistent data curation domain. Through an RSS interface for recent datasets PanMetaWorks allows project members to be informed about data uploaded by other project members. The implementation of the OAI-PMH interface can be used to syndicate data catalogs to research data portals, such as the panFMP data portal framework. Once data objects are uploaded to the eSciDoc infrastructure it is possible to drop the software instance that was used for collecting the data, while the compiled data and metadata are accessible for other authorized applications through the institution's eSciDoc middleware. This approach of "expendable data curation tools" allows for a significant reduction in costs for software maintenance as expensive data capture applications do not need to be maintained indefinitely to ensure long term access to the stored data.
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Finite Element Modeling of Viscoelastic Behavior and Interface Damage in Adhesively Bonded Joints
2012-01-01
eccentricity of the axis of a lap joint gives rise to transverse or peel stresses at the Report Documentation Page Form ApprovedOMB No. 0704-0188...Computers and Structures 29, 1011 (1988). 21 S. Roy and J. N. Reddy, Tire Sci. Technol. 16, 146 (1988). 22 S. Roy and J. N. Reddy, Intl. J. Numer
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Xu, Chen; Klaw, Michelle C.; Lemay, Michel A.; Baas, Peter W.; Tom, Veronica J.
2014-01-01
While it is well established that the axons of adult neurons have a lower capacity for regrowth, some regeneration of certain CNS populations after spinal cord injury (SCI) is possible if their axons are provided with a permissive substrate, such as an injured peripheral nerve. While some axons readily regenerate into a peripheral nerve graft (PNG), these axons almost always stall at the distal interface and fail to re-innervate spinal cord tissue. Treatment of the glial scar at the distal graft interface with chondroitinase ABC (ChABC) can improve regeneration, but most regenerated axons need further stimulation to extend beyond the interface. Previous studies demonstrate that pharmacologically inhibiting kinesin-5, a motor protein best known for its essential role in mitosis but also expressed in neurons, with the pharmacological agent monastrol increases axon growth on inhibitory substrates in vitro. We sought to determine if monastrol treatment after a SCI improves functional axon regeneration. Animals received complete thoracic level 7 (T7) transections and PNGs and were treated intrathecally with ChABC and either monastrol or DMSO vehicle. We found that combining ChABC with monastrol significantly enhanced axon regeneration. However, there were no further improvements in function or enhanced c-Fos induction upon stimulation of spinal cord rostral to the transection. This indicates that monastrol improves ChABC-mediated axon regeneration but that further treatments are needed to enhance the integration of these regrown axons. PMID:25447935
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Ab Initio Predictions of Hexagonal Zr(B,C,N) Polymorphs for Coherent Interface Design
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hu, Chongze; Huang, Jingsong; Sumpter, Bobby G.
2017-10-27
Density functional theory calculations are used to explore hexagonal (HX) NiAs-like polymorphs of Zr(B,C,N) and compare with corresponding Zr(B,C,N) Hagg-like face-centered cubic rocksalt (B1) phases. While all predicted compounds are mechanically stable according to the Born-Huang criteria, only HX Zr(C,N) are found dynamically stable from ab initio molecular dynamics simulations and lattice dynamics calculations. HX ZrN emerges as a candidate structure with ground state energy, elastic constants, and extrinsic mechanical parameters comparable with those of B1 ZrN. Ab initio band structure and semi-classical Boltzmann transport calculations predict a metallic character and a monotonic increase in electrical conductivity with the numbermore » of valence electrons. Electronic structure calculations indicate that the HX phases gain their stability and mechanical attributes by Zr d- non-metal p hybridization and by broadening of Zr d bands. Furthermore, it is shown that the HX ZrN phase provides a low-energy coherent interface model for connecting B1 ZrN domains, with significant energetic advantage over an atomistic interface model derived from high resolution transmission electron microscopy images. The ab initio characterizations provided herein should aid the experimental identification of non-Hagg-like hard phases. Furthermore, the results can also enrich the variety of crystalline phases potentially available for designing coherent interfaces in superhard nanostructured materials and in materials with multilayer characteristics.« less
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A preprocessor for the Urbana coherent-scatter radar
NASA Technical Reports Server (NTRS)
Zendt, F. T.; Bowhill, S. A.
1982-01-01
The design, interfacing, testing, and operation of a preprocessor to increase the altitude and temporal resolution of the present coherent-scatter system are described. This system upgrade requires an increase in the data collection rate. Replacing the present, relatively slow, ADC with two high speed ADCs achieves the increased echo sampling rate desired. To stay within the capabilities of the main computer's I/O and processing rate the data must be reduced before transfer to the main computer. Thus the preprocessor also coherently integrates the data before transfer.
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Self-paced brain-computer interface control of ambulation in a virtual reality environment.
Wang, Po T; King, Christine E; Chui, Luis A; Do, An H; Nenadic, Zoran
2012-10-01
Spinal cord injury (SCI) often leaves affected individuals unable to ambulate. Electroencephalogram (EEG) based brain-computer interface (BCI) controlled lower extremity prostheses may restore intuitive and able-body-like ambulation after SCI. To test its feasibility, the authors developed and tested a novel EEG-based, data-driven BCI system for intuitive and self-paced control of the ambulation of an avatar within a virtual reality environment (VRE). Eight able-bodied subjects and one with SCI underwent the following 10-min training session: subjects alternated between idling and walking kinaesthetic motor imageries (KMI) while their EEG were recorded and analysed to generate subject-specific decoding models. Subjects then performed a goal-oriented online task, repeated over five sessions, in which they utilized the KMI to control the linear ambulation of an avatar and make ten sequential stops at designated points within the VRE. The average offline training performance across subjects was 77.2 ± 11.0%, ranging from 64.3% (p = 0.001 76) to 94.5% (p = 6.26 × 10(-23)), with chance performance being 50%. The average online performance was 8.5 ± 1.1 (out of 10) successful stops and 303 ± 53 s completion time (perfect = 211 s). All subjects achieved performances significantly different than those of random walk (p < 0.05) in 44 of the 45 online sessions. By using a data-driven machine learning approach to decode users' KMI, this BCI-VRE system enabled intuitive and purposeful self-paced control of ambulation after only 10 minutes training. The ability to achieve such BCI control with minimal training indicates that the implementation of future BCI-lower extremity prosthesis systems may be feasible.
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NASA Astrophysics Data System (ADS)
Müller-Putz, G. R.; Daly, I.; Kaiser, V.
2014-06-01
Objective. Assimilating the diagnosis complete spinal cord injury (SCI) takes time and is not easy, as patients know that there is no ‘cure' at the present time. Brain-computer interfaces (BCIs) can facilitate daily living. However, inter-subject variability demands measurements with potential user groups and an understanding of how they differ to healthy users BCIs are more commonly tested with. Thus, a three-class motor imagery (MI) screening (left hand, right hand, feet) was performed with a group of 10 able-bodied and 16 complete spinal-cord-injured people (paraplegics, tetraplegics) with the objective of determining what differences were present between the user groups and how they would impact upon the ability of these user groups to interact with a BCI. Approach. Electrophysiological differences between patient groups and healthy users are measured in terms of sensorimotor rhythm deflections from baseline during MI, electroencephalogram microstate scalp maps and strengths of inter-channel phase synchronization. Additionally, using a common spatial pattern algorithm and a linear discriminant analysis classifier, the classification accuracy was calculated and compared between groups. Main results. It is seen that both patient groups (tetraplegic and paraplegic) have some significant differences in event-related desynchronization strengths, exhibit significant increases in synchronization and reach significantly lower accuracies (mean (M) = 66.1%) than the group of healthy subjects (M = 85.1%). Significance. The results demonstrate significant differences in electrophysiological correlates of motor control between healthy individuals and those individuals who stand to benefit most from BCI technology (individuals with SCI). They highlight the difficulty in directly translating results from healthy subjects to participants with SCI and the challenges that, therefore, arise in providing BCIs to such individuals.
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Forces between a rigid probe particle and a liquid interface. II. The general case.
Dagastine, R R; White, L R
2002-03-15
The semianalytic theory developed previously (Chan, D. Y. C., Dagastine, R. R., and White, L. R., J. Colloid Interface Sci. 236, 141 (2001)) to predict the force curve of an AFM measurement at a liquid interface using a colloidal probe has been expanded to incorporate a general force law with both attractive and repulsive forces. Expressions for the gradient of the force curve are developed to calculate the point at which the probe particle on the cantilever will spontaneously jump in toward the liquid interface. The calculation of the jump instability is reduced to a straightforward embroidery of the simple algorithms presented in Chan et al. In a variety of sample calculations using force laws including van der Waals, electrostatic, and hydrophobic forces for both oil/water and bubble/water interfaces, we have duplicated the general behaviors observed in several AFM investigations at liquid interfaces. The behavior of the drop as a Hookean spring and the numerical difficulties of a full numerical calculation of F(deltaX) are also discussed.
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Potassium Homeostasis: The Knowns, the Unknowns, and the Health Benefits.
McDonough, Alicia A; Youn, Jang H
2017-03-01
Potassium homeostasis has a very high priority because of its importance for membrane potential. Although extracellular K + is only 2% of total body K + , our physiology was evolutionarily tuned for a high-K + , low-Na + diet. We review how multiple systems interface to accomplish fine K + balance and the consequences for health and disease. ©2017 Int. Union Physiol. Sci./Am. Physiol. Soc.
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Coherent Dynamics of a Hybrid Quantum Spin-Mechanical Oscillator System
NASA Astrophysics Data System (ADS)
Lee, Kenneth William, III
A fully functional quantum computer must contain at least two important components: a quantum memory for storing and manipulating quantum information and a quantum data bus to securely transfer information between quantum memories. Typically, a quantum memory is composed of a matter system, such as an atom or an electron spin, due to their prolonged quantum coherence. Alternatively, a quantum data bus is typically composed of some propagating degree of freedom, such as a photon, which can retain quantum information over long distances. Therefore, a quantum computer will likely be a hybrid quantum device, consisting of two or more disparate quantum systems. However, there must be a reliable and controllable quantum interface between the memory and bus in order to faithfully interconvert quantum information. The current engineering challenge for quantum computers is scaling the device to large numbers of controllable quantum systems, which will ultimately depend on the choice of the quantum elements and interfaces utilized in the device. In this thesis, we present and characterize a hybrid quantum device comprised of single nitrogen-vacancy (NV) centers embedded in a high quality factor diamond mechanical oscillator. The electron spin of the NV center is a leading candidate for the realization of a quantum memory due to its exceptional quantum coherence times. On the other hand, mechanical oscillators are highly sensitive to a wide variety of external forces, and have the potential to serve as a long-range quantum bus between quantum systems of disparate energy scales. These two elements are interfaced through crystal strain generated by vibrations of the mechanical oscillator. Importantly, a strain interface allows for a scalable architecture, and furthermore, opens the door to integration into a larger quantum network through coupling to an optical interface. There are a few important engineering challenges associated with this device. First, there have been no previous demonstrations of a strain-mediated spin-mechanical interface and hence the system is largely uncharacterized. Second, fabricating high quality diamond mechanical oscillators is difficult due to the robust and chemically inert nature of diamond. Finally, engineering highly coherent NV centers with a coherent optical interface in nanostructured diamond remains an outstanding challenge. In this thesis, we theoretically and experimentally address each of these challenges, and show that with future improvements, this device is suitable for future quantum-enabled applications. First, we theoretically and experimentally demonstrate a dynamic, strain-mediated coupling between the spin and orbital degrees of freedom of the NV center and the driven mechanical motion of a single-crystal diamond cantilever. We employ Ramsey interferometry to demonstrate coherent, mechanical driving of the NV spin evolution. Using this interferometry technique, we present the first demonstration of nanoscale strain imaging, and quantitatively characterize the previously unknown spin-strain coupling constants. Next, we use the driven motion of the cantilever to perform deterministic control of the frequency and polarization dependence of the optical transitions of the NV center. Importantly, this experiment constitutes the first demonstration of on-chip control of both the frequency and polarization state of a single photon produced by a quantum emitter. In the final experiment, we use mechanical driving to engineer a series of spin ``clock" states and demonstrate a significant increase in the spin coherence time of the NV center. We conclude this thesis with a theoretical discussion of prospective applications for this device, including generation of non-classical mechanical states and spin-spin entanglement, as well as an evaluation of the current limitations of our devices, including a possible avenues for improvement to reach the regime of strong spin-phonon coupling.
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Grahn, Peter J.; Mallory, Grant W.; Berry, B. Michael; Hachmann, Jan T.; Lobel, Darlene A.; Lujan, J. Luis
2014-01-01
Movement is planned and coordinated by the brain and carried out by contracting muscles acting on specific joints. Motor commands initiated in the brain travel through descending pathways in the spinal cord to effector motor neurons before reaching target muscles. Damage to these pathways by spinal cord injury (SCI) can result in paralysis below the injury level. However, the planning and coordination centers of the brain, as well as peripheral nerves and the muscles that they act upon, remain functional. Neuroprosthetic devices can restore motor function following SCI by direct electrical stimulation of the neuromuscular system. Unfortunately, conventional neuroprosthetic techniques are limited by a myriad of factors that include, but are not limited to, a lack of characterization of non-linear input/output system dynamics, mechanical coupling, limited number of degrees of freedom, high power consumption, large device size, and rapid onset of muscle fatigue. Wireless multi-channel closed-loop neuroprostheses that integrate command signals from the brain with sensor-based feedback from the environment and the system's state offer the possibility of increasing device performance, ultimately improving quality of life for people with SCI. In this manuscript, we review neuroprosthetic technology for improving functional restoration following SCI and describe brain-machine interfaces suitable for control of neuroprosthetic systems with multiple degrees of freedom. Additionally, we discuss novel stimulation paradigms that can improve synergy with higher planning centers and improve fatigue-resistant activation of paralyzed muscles. In the near future, integration of these technologies will provide SCI survivors with versatile closed-loop neuroprosthetic systems for restoring function to paralyzed muscles. PMID:25278830
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Choudhuri, D; Banerjee, R; Srinivasan, S G
2017-01-17
The extraordinary creep-resistance of Mg-Nd-based alloys can be correlated to the formation of nanoscale-platelets of β 1 -Mg 3 Nd precipitates, that grow along 〈110〉 Mg in bulk hcp-Mg and on dislocation lines. The growth kinetics of β 1 is sluggish even at high temperatures, and presumably occurs via vacancy migration. However, the rationale for the high-temperature stability of precipitate-matrix interfaces and observed growth direction is unknown, and may likely be related to the interfacial structure and excess energy. Therefore, we study two interfaces- {112} β1 /{100} Mg and {111} β1 /{110} Mg - that are commensurate with β 1 /hcp-Mg orientation relationship via first principles calculations. We find that β 1 acquires plate-like morphology to reduce small lattice strain via the formation of energetically favorable {112} β1 /{100} Mg interfaces, and predict that β 1 grows along 〈110〉 Mg on dislocation lines due to the migration of metastable {111} β1 /{110} Mg . Furthermore, electronic charge distribution of the two interfaces studied here indicated that interfacial-energy of coherent precipitates is sensitive to the population of distorted lattice sites, and their spatial extent in the vicinity of interfaces. Our results have implications for alloy design as they suggest that formation of β 1 -like precipitates in the hcp-Mg matrix will require well-bonded coherent interface along precipitate broad-faces, while simultaneously destabilizing other interfaces.
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Interface induced spin-orbit interaction in silicon quantum dots and prospects of scalability
NASA Astrophysics Data System (ADS)
Ferdous, Rifat; Wai, Kok; Veldhorst, Menno; Hwang, Jason; Yang, Henry; Klimeck, Gerhard; Dzurak, Andrew; Rahman, Rajib
A scalable quantum computing architecture requires reproducibility over key qubit properties, like resonance frequency, coherence time etc. Randomness in these properties would necessitate individual knowledge of each qubit in a quantum computer. Spin qubits hosted in Silicon (Si) quantum dots (QD) is promising as a potential building block for a large-scale quantum computer, because of their longer coherence times. The Stark shift of the electron g-factor in these QDs has been used to selectively address multiple qubits. From atomistic tight-binding studies we investigated the effect of interface non-ideality on the Stark shift of the g-factor in a Si QD. We find that based on the location of a monoatomic step at the interface with respect to the dot center both the sign and magnitude of the Stark shift change. Thus the presence of interface steps in these devices will cause variability in electron g-factor and its Stark shift based on the location of the qubit. This behavior will also cause varying sensitivity to charge noise from one qubit to another, which will randomize the dephasing times T2*. This predicted device-to-device variability is experimentally observed recently in three qubits fabricated at a Si/Si02 interface, which validates the issues discussed.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Zimnyakov, D. A., E-mail: zimnykov@sgu.ru; Sadovoi, A. V.; Vilenskii, M. A.
2009-02-15
Image sequences of the surface of disordered layers of porous medium (paper) obtained under noncoherent and coherent illumination during capillary rise of a liquid are analyzed. As a result, principles that govern the critical behavior of the interface between liquid and gaseous phases during its pinning are established. By a cumulant analysis of speckle-modulated images of the surface and by the statistical analysis of binarized difference images of the surface under noncoherent illumination, it is shown that the macroscopic dynamics of the interface at the stage of pinning is mainly controlled by the power law dependence of the appearance ratemore » of local instabilities (avalanches) of the interface on the critical parameter, whereas the growth dynamics of the local instabilities is controlled by the diffusion of a liquid in a layer and weakly depends on the critical parameter. A phenomenological model is proposed for the macroscopic dynamics of the phase interface for interpreting experimental data. The values of critical indices are determined that characterize the samples under test within this model. These values are compared with the results of numerical simulation for discrete models of directed percolation corresponding to the Kardar-Parisi-Zhang equation.« less
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Mirador: A Simple, Fast Search Interface for Remote Sensing Data
NASA Technical Reports Server (NTRS)
Lynnes, Christopher; Strub, Richard; Seiler, Edward; Joshi, Talak; MacHarrie, Peter
2008-01-01
A major challenge for remote sensing science researchers is searching and acquiring relevant data files for their research projects based on content, space and time constraints. Several structured query (SQ) and hierarchical navigation (HN) search interfaces have been develop ed to satisfy this requirement, yet the dominant search engines in th e general domain are based on free-text search. The Goddard Earth Sci ences Data and Information Services Center has developed a free-text search interface named Mirador that supports space-time queries, inc luding a gazetteer and geophysical event gazetteer. In order to compe nsate for a slightly reduced search precision relative to SQ and HN t echniques, Mirador uses several search optimizations to return result s quickly. The quick response enables a more iterative search strateg y than is available with many SQ and HN techniques.
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Designs towards improved coherence times in superconducting qubits
NASA Astrophysics Data System (ADS)
Corcoles, Antonio; Chow, Jerry; Gambetta, Jay; Rigetti, Chad; Rozen, Jim; Keefe, George; Rothwell, Mary Beth; Poletto, Stefano; Ketchen, Mark; Steffen, Matthias
2012-02-01
Coherence times for superconducting qubits in a planar geometry have increased drastically over the past 10 years with improvements exceeding a factor of 1000. However, recently these appeared to have reached a plateau around 1-2 microseconds, the limits of which were not well understood. Here, we present experimental data showing that one limit is due to infra-red radiation, confirming observations from other groups. We observe increased coherence times after appropriate IR shielding. Further improvements are shown to be possible by increasing the feature size of the interdigitated shunting capacitor, strongly indicating that surface losses at the metal/substrate interface are limiting qubit coherence times. In our experiments we kept the ratio of line width to gap size constant, but increased the overall feature size. We will discuss this and other similar design approaches towards better coherence in superconducting qubits.
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Mesoscopic coherence in light scattering from cold, optically dense and disordered atomic systems
NASA Astrophysics Data System (ADS)
Kupriyanov, D. V.; Sokolov, I. M.; Havey, M. D.
2017-02-01
Coherent effects manifested in light scattering from cold, optically dense and disordered atomic systems are reviewed from a primarily theoretical point of view. Development of the basic theoretical tools is then elaborated through several physical atomic physics based processes which have been at least partly explored experimentally. These include illustrations drawn from the coherent backscattering effect, random lasing in atomic gases, quantum memories and light-atoms interface assisted by the light trapping mechanism. Current understanding and challenges associated with the transition to high atomic densities and cooperativity in the scattering process are also discussed in some detail.
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Quantifying the human-robot interaction forces between a lower limb exoskeleton and healthy users.
Rathore, Ashish; Wilcox, Matthew; Ramirez, Dafne Zuleima Morgado; Loureiro, Rui; Carlson, Tom
2016-08-01
To counter the many disadvantages of prolonged wheelchair use, patients with spinal cord injuries (SCI) are beginning to turn towards robotic exoskeletons. However, we are currently unaware of the magnitude and distribution of forces acting between the user and the exoskeleton. This is a critical issue, as SCI patients have an increased susceptibility to skin lesions and pressure ulcer development. Therefore, we developed a real-time force measuring apparatus, which was placed at the physical human-robot interface (pHRI) of a lower limb robotic exoskeleton. Experiments captured the dynamics of these interaction forces whilst the participants performed a range of typical stepping actions. Our results indicate that peak forces occurred at the anterior aspect of both the left and right legs, areas that are particularly prone to pressure ulcer development. A significant difference was also found between the average force experienced at the anterior and posterior sensors of the right thigh during the swing phase for different movement primitives. These results call for the integration of instrumented straps as standard in lower limb exoskeletons. They also highlight the potential of such straps to be used as an alternative/complementary interface for the high-level control of lower limb exoskeletons in some patient groups.
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Donati, Ana R C; Shokur, Solaiman; Morya, Edgard; Campos, Debora S F; Moioli, Renan C; Gitti, Claudia M; Augusto, Patricia B; Tripodi, Sandra; Pires, Cristhiane G; Pereira, Gislaine A; Brasil, Fabricio L; Gallo, Simone; Lin, Anthony A; Takigami, Angelo K; Aratanha, Maria A; Joshi, Sanjay; Bleuler, Hannes; Cheng, Gordon; Rudolph, Alan; Nicolelis, Miguel A L
2016-08-11
Brain-machine interfaces (BMIs) provide a new assistive strategy aimed at restoring mobility in severely paralyzed patients. Yet, no study in animals or in human subjects has indicated that long-term BMI training could induce any type of clinical recovery. Eight chronic (3-13 years) spinal cord injury (SCI) paraplegics were subjected to long-term training (12 months) with a multi-stage BMI-based gait neurorehabilitation paradigm aimed at restoring locomotion. This paradigm combined intense immersive virtual reality training, enriched visual-tactile feedback, and walking with two EEG-controlled robotic actuators, including a custom-designed lower limb exoskeleton capable of delivering tactile feedback to subjects. Following 12 months of training with this paradigm, all eight patients experienced neurological improvements in somatic sensation (pain localization, fine/crude touch, and proprioceptive sensing) in multiple dermatomes. Patients also regained voluntary motor control in key muscles below the SCI level, as measured by EMGs, resulting in marked improvement in their walking index. As a result, 50% of these patients were upgraded to an incomplete paraplegia classification. Neurological recovery was paralleled by the reemergence of lower limb motor imagery at cortical level. We hypothesize that this unprecedented neurological recovery results from both cortical and spinal cord plasticity triggered by long-term BMI usage.
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Donati, Ana R. C.; Shokur, Solaiman; Morya, Edgard; Campos, Debora S. F.; Moioli, Renan C.; Gitti, Claudia M.; Augusto, Patricia B.; Tripodi, Sandra; Pires, Cristhiane G.; Pereira, Gislaine A.; Brasil, Fabricio L.; Gallo, Simone; Lin, Anthony A.; Takigami, Angelo K.; Aratanha, Maria A.; Joshi, Sanjay; Bleuler, Hannes; Cheng, Gordon; Rudolph, Alan; Nicolelis, Miguel A. L.
2016-01-01
Brain-machine interfaces (BMIs) provide a new assistive strategy aimed at restoring mobility in severely paralyzed patients. Yet, no study in animals or in human subjects has indicated that long-term BMI training could induce any type of clinical recovery. Eight chronic (3–13 years) spinal cord injury (SCI) paraplegics were subjected to long-term training (12 months) with a multi-stage BMI-based gait neurorehabilitation paradigm aimed at restoring locomotion. This paradigm combined intense immersive virtual reality training, enriched visual-tactile feedback, and walking with two EEG-controlled robotic actuators, including a custom-designed lower limb exoskeleton capable of delivering tactile feedback to subjects. Following 12 months of training with this paradigm, all eight patients experienced neurological improvements in somatic sensation (pain localization, fine/crude touch, and proprioceptive sensing) in multiple dermatomes. Patients also regained voluntary motor control in key muscles below the SCI level, as measured by EMGs, resulting in marked improvement in their walking index. As a result, 50% of these patients were upgraded to an incomplete paraplegia classification. Neurological recovery was paralleled by the reemergence of lower limb motor imagery at cortical level. We hypothesize that this unprecedented neurological recovery results from both cortical and spinal cord plasticity triggered by long-term BMI usage. PMID:27513629
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Relief of neuropathic pain after spinal cord injury by brain-computer interface training.
Yoshida, Naoki; Hashimoto, Yasunari; Shikota, Mio; Ota, Tetsuo
2016-01-01
The aim of this study was to report the effects of brain-computer interface (BCI) training, a neurofeedback rehabilitation technique, on persistent neuropathic pain (NP) after cervical spinal cord injury (SCI). We present the case of a 71-year-old woman with NP in her left upper extremity after SCI (C8). She underwent BCI training as outpatient rehabilitation for 4 months to enhance event-related desynchronization (ERD), which is triggered by the patient's motor intuition. Scalp electroencephalography was recorded to observe the ERD during every BCI training session. The patient's pain was evaluated with the McGill Pain Questionnaire (MPQ) and a visual analog scale (VAS). The MPQ was performed after every BCI training session, and the patient assessed the VAS score on her own, once every few days during the BCI training period. After the BCI training started, the patient's ERD during the BCI training period increased significantly, from 15.6-30.3%. Moreover, her VAS score decreased gradually, from 8 to 5, after the BCI training started, although the MPQ did not change significantly. BCI training has the potential to provide relief for patients with persistent NP via brain plasticity, and to improve their activities of daily living and quality of life.
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Earth Science community support in the EGI-Inspire Project
NASA Astrophysics Data System (ADS)
Schwichtenberg, H.
2012-04-01
The Earth Science Grid community is following its strategy of propagating Grid technology to the ES disciplines, setting up interactive collaboration among the members of the community and stimulating the interest of stakeholders on the political level since ten years already. This strategy was described in a roadmap published in an Earth Science Informatics journal. It was applied through different European Grid projects and led to a large Grid Earth Science VRC that covers a variety of ES disciplines; in the end, all of them were facing the same kind of ICT problems. .. The penetration of Grid in the ES community is indicated by the variety of applications, the number of countries in which ES applications are ported, the number of papers in international journals and the number of related PhDs. Among the six virtual organisations belonging to ES, one, ESR, is generic. Three others -env.see-grid-sci.eu, meteo.see-grid-sci.eu and seismo.see-grid-sci.eu- are thematic and regional (South Eastern Europe) for environment, meteorology and seismology. The sixth VO, EGEODE, is for the users of the Geocluster software. There are also ES users in national VOs or VOs related to projects. The services for the ES task in EGI-Inspire concerns the data that are a key part of any ES application. The ES community requires several interfaces to access data and metadata outside of the EGI infrastructure, e.g. by using grid-enabled database interfaces. The data centres have also developed service tools for basic research activities such as searching, browsing and downloading these datasets, but these are not accessible from applications executed on the Grid. The ES task in EGI-Inspire aims to make these tools accessible from the Grid. In collaboration with GENESI-DR (Ground European Network for Earth Science Interoperations - Digital Repositories) this task is maintaining and evolving an interface in response to new requirements that will allow data in the GENESI-DR infrastructure to be accessed from EGI resources to enable future research activities by this HUC. The international climate community for IPCC has created the Earth System Grid (ESG) to store and share climate data. There is a need to interface ESG with EGI for climate studies - parametric, regional and impact aspects. Critical points concern the interoperability of security mechanism between both "organisations", data protection policy, data transfer, data storage and data caching. Presenter: Horst Schwichtenberg Co-Authors: Monique Petitdidier (IPSL), Andre Gemünd (SCAI), Wim Som de Cerff (KNMI), Michael Schnell (SCAI)
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The Coherent Interlayer Resistance of a Single, Misoriented Interface between Two Graphite Stacks
NASA Astrophysics Data System (ADS)
Lake, Roger K.; Habib, K. M. Masum; Sylvia, Somaia; Ge, Supeng; Neupane, Mahesh
2014-03-01
The coherent, interlayer resistance of a misoriented, rotated interface between two stacks of AB graphite is determined for a variety of misorientation angles ranging from 0° to 27 .29° . The quantum-resistance of the ideal AB stack is on the order of 1 to 10 m Ωμm2 depending on the Fermi energy. For small rotation angles <= 7 .34° , the coherent interlayer resistance exponentially approaches the ideal quantum resistance at energies away from the charge neutrality point. Over a range of intermediate angles, the resistance increases exponentially with primitive cell size for minimum size cells. A change of misorientation angle by one degree can increase the primitive cell size by three orders of magnitude. These large cell sizes may not follow the exponential trend of the minimal cells especially at energies a few hundred meV away from the charge neutrality point. At such energies, their coherent interlayer resistance is likely to coincide with that of a nearby rotation angle with a much smaller primitive cell. The energy dependence of the interlayer transmission is described and analyzed. This work was supported in part by FAME, one of six centers of STARnet, a Semiconductor Research Corporation program sponsored by MARCO and DARPA.
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Multiple quantum criticality in a two-dimensional superconductor
NASA Astrophysics Data System (ADS)
Biscaras, J.; Bergeal, N.; Hurand, S.; Feuillet-Palma, C.; Rastogi, A.; Budhani, R. C.; Grilli, M.; Caprara, S.; Lesueur, J.
2013-06-01
The diverse phenomena associated with the two-dimensional electron gas (2DEG) that occurs at oxide interfaces include, among others, exceptional carrier mobilities, magnetism and superconductivity. Although these have mostly been the focus of interest for potential future applications, they also offer an opportunity for studying more fundamental quantum many-body effects. Here, we examine the magnetic-field-driven quantum phase transition that occurs in electrostatically gated superconducting LaTiO3/SrTiO3 interfaces. Through a finite-size scaling analysis, we show that it belongs to the (2+1)D XY model universality class. The system can be described as a disordered array of superconducting puddles coupled by a 2DEG and, depending on its conductance, the observed critical behaviour is single (corresponding to the long-range phase coherence in the whole array) or double (one related to local phase coherence, the other one to the array). A phase diagram illustrating the dependence of the critical field on the 2DEG conductance is constructed, and shown to agree with theoretical proposals. Moreover, by retrieving the coherence-length critical exponent ν, we show that the quantum critical behaviour can be clean or dirty according to the Harris criterion, depending on whether the phase-coherence length is smaller or larger than the size of the puddles.
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Multiple quantum criticality in a two-dimensional superconductor.
Biscaras, J; Bergeal, N; Hurand, S; Feuillet-Palma, C; Rastogi, A; Budhani, R C; Grilli, M; Caprara, S; Lesueur, J
2013-06-01
The diverse phenomena associated with the two-dimensional electron gas (2DEG) that occurs at oxide interfaces include, among others, exceptional carrier mobilities, magnetism and superconductivity. Although these have mostly been the focus of interest for potential future applications, they also offer an opportunity for studying more fundamental quantum many-body effects. Here, we examine the magnetic-field-driven quantum phase transition that occurs in electrostatically gated superconducting LaTiO3/SrTiO3 interfaces. Through a finite-size scaling analysis, we show that it belongs to the (2+1)D XY model universality class. The system can be described as a disordered array of superconducting puddles coupled by a 2DEG and, depending on its conductance, the observed critical behaviour is single (corresponding to the long-range phase coherence in the whole array) or double (one related to local phase coherence, the other one to the array). A phase diagram illustrating the dependence of the critical field on the 2DEG conductance is constructed, and shown to agree with theoretical proposals. Moreover, by retrieving the coherence-length critical exponent ν, we show that the quantum critical behaviour can be clean or dirty according to the Harris criterion, depending on whether the phase-coherence length is smaller or larger than the size of the puddles.
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Effects of Molybdenum Addition on Hydrogen Desorption of TiC Precipitation-Hardened Steel
NASA Astrophysics Data System (ADS)
Song, Eun Ju; Baek, Seung-Wook; Nahm, Seung Hoon; Suh, Dong-Woo
2018-05-01
The hydrogen-trap states in TiC and MoC that have coherent interfaces with ferrite were investigated using first-principles calculation. The trapping sites of TiC were the interfaces and interstitial sites of ferrite. On the other hand, the trapping sites of MoC were ferrite interstitial sites; the interface had a negative binding energy with H. Thermal desorption analysis confirms that the amounts of diffusible hydrogen were significantly reduced by addition of Mo in Ti-bearing steel.
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2015-01-03
Dissociation in Perovskite Solar Cells Yu-Che Hsiao, Ting Wu, Mingxing Li, and Bin Hu Advanced Materials, DOI: 10.1002/adma.201405946, 2015 2...Electrode Interface and Donor/Acceptor Interface via Charge Dissociation in Organic Solar Cells at Device-Operating Condition Ting Wu, Yu-Che Hsiao...exchange energy at donor:acceptor interfaces in organic solar cells Mingxing Li, Hongfeng Wang, Lei He, Huidong Zang, Hengxing Xu, and Bin Hu Appl
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Segmentation of 830- and 1310-nm LASIK corneal optical coherence tomography images
NASA Astrophysics Data System (ADS)
Li, Yan; Shekhar, Raj; Huang, David
2002-05-01
Optical coherence tomography (OCT) provides a non-contact and non-invasive means to visualize the corneal anatomy at micron scale resolution. We obtained corneal images from an arc-scanning (converging) OCT system operating at a wavelength of 830nm and a fan-shaped-scanning high-speed OCT system with an operating wavelength of 1310nm. Different scan protocols (arc/fan) and data acquisition rates, as well as wavelength dependent bio-tissue backscatter contrast and optical absorption, make the images acquired using the two systems different. We developed image-processing algorithms to automatically detect the air-tear interface, epithelium-Bowman's layer interface, laser in-situ keratomileusis (LASIK) flap interface, and the cornea-aqueous interface in both kinds of images. The overall segmentation scheme for 830nm and 1310nm OCT images was similar, although different strategies were adopted for specific processing approaches. Ultrasound pachymetry measurements of the corneal thickness and Placido-ring based corneal topography measurements of the corneal curvature were made on the same day as the OCT examination. Anterior/posterior corneal surface curvature measurement with OCT was also investigated. Results showed that automated segmentation of OCT images could evaluate anatomic outcome of LASIK surgery.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Yadav, Satyesh Kumar; Shao, S.; Chen, Youxing
Here, using a newly developed embedded-atom-method potential for Mg–Nb, the semi-coherent Mg/Nb interface with the Kurdjumov–Sachs orientation relationship is studied. Atomistic simulations have been carried out to understand the shear strength of the interface, as well as the interaction between lattice glide dislocations and the interface. The interface shear mechanisms are dependent on the shear loading directions, through either interface sliding between Mg and Nb atomic layers or nucleation and gliding of Shockley partial dislocations in between the first two atomic planes in Mg at the interface. The shear strength for the Mg/Nb interface is found to be generally high,more » in the range of 0.9–1.3 GPa depending on the shear direction. As a consequence, the extents of dislocation core spread into the interface are considerably small, especially when compared to the case of other “weak” interfaces such as the Cu/Nb interface.« less
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Nanoscale strengthening mechanisms in metallic thin film systems
NASA Astrophysics Data System (ADS)
Schoeppner, Rachel Lynn
Nano-scale strengthening mechanisms for thin films were investigated for systems governed by two different strengthening techniques: nano-laminate strengthening and oxide dispersion strengthening. Films were tested under elevated temperature conditions to investigate changes in deformation mechanisms at different operating temperatures, and the structural stability. Both systems exhibit remarkable stability after annealing and thus long-term reliability. Nano-scale metallic multilayers with smaller layer thicknesses show a greater relative resistance to decreasing strength at higher temperature testing conditions than those with larger layer thicknesses. This is seen in both Cu/Ni/Nb multilayers as well as a similar tri-component bi-layer system (Cu-Ni/Nb), which removed the coherent interface from the film. Both nanoindentation and micro-pillar compression tests investigated the strain-hardening ability of these two systems to determine what role the coherent interface plays in this mechanism. Tri-layer films showed a higher strain-hardening ability as the layer thickness decreased and a higher strain-hardening exponent than the bi-layer system: verifying the presence of a coherent interface increases the strain-hardening ability of these multilayer systems. Both systems exhibited hardening of the room temperature strength after annealing, suggesting a change in microstructure has occurred, unlike that seen in other multilayer systems. Oxide dispersion strengthened Au films showed a marked increase in hardness and wear resistance with the addition of ZnO particles. The threshold for stress-induced grain-refinement as opposed to grain growth is seen at concentrations of at least 0.5 vol%. These systems exhibited stable microstructures during thermal cycling in films containing at least 1.0%ZnO. Nanoindentation experiments show the drop in hardness following annealing is almost completely attributed to the resulting grain growth. Four-point probe resistivity measurements on annealed films showed a significant drop in resistivity for the higher concentration ZnO films, which is proposed to be the result of a change in the particle-matrix interface structure. A model connecting the hardness and resistivity as a function of ZnO concentration has been developed based on the assumption that the impact of nm-scale ZnO precipitates on the mechanical and electrical behavior of Au films is likely dominated by a transition from semi-coherent to incoherent interfaces.
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Nanoscale self-templating for oxide epitaxy with large symmetry mismatch
Gao, Xiang; Lee, Shinbuhm; Nichols, John A.; ...
2016-12-02
Direct observations using scanning transmission electron microscopy unveil an intriguing interfacial bi-layer that enables epitaxial growth of a strain-free, monoclinic, bronze-phase VO 2(B) thin film on a perovskite SrTiO 3 (STO) substrate. For this study, we observe an ultrathin (2–3 unit cells) interlayer best described as highly strained VO 2(B) nanodomains combined with an extra (Ti,V)O 2 layer on the TiO 2 terminated STO (001) surface. By forming a fully coherent interface with the STO substrate and a semi-coherent interface with the strain-free epitaxial VO 2(B) film above, the interfacial bi-layer enables the epitaxial connection of the two materials despitemore » their large symmetry and lattice mismatch.« less
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Retrieving Coherent Receiver Function Images with Dense Arrays
NASA Astrophysics Data System (ADS)
Zhong, M.; Zhan, Z.
2016-12-01
Receiver functions highlight converted phases (e.g., Ps, PpPs, sP) and have been widely used to study seismic interfaces. With a dense array, receiver functions (RFs) at multiple stations form a RF image that can provide more robust/detailed constraints. However, due to noise in data, non-uniqueness of deconvolution, and local structures that cannot be detected across neighboring stations, traditional RF images are often noisy and hard to interpret. Previous attempts to enhance coherence by stacking RFs from multiple events or post-filtering the RF images have not produced satisfactory improvements. Here, we propose a new method to retrieve coherent RF images with dense arrays. We take advantage of the waveform coherency at neighboring stations and invert for a small number of coherent arrivals for their RFs. The new RF images contain only the coherent arrivals required to fit data well. Synthetic tests and preliminary applications on real data demonstrate that the new RF images are easier to interpret and improve our ability to infer Earth structures using receiver functions.
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ScyFlow: An Environment for the Visual Specification and Execution of Scientific Workflows
NASA Technical Reports Server (NTRS)
McCann, Karen M.; Yarrow, Maurice; DeVivo, Adrian; Mehrotra, Piyush
2004-01-01
With the advent of grid technologies, scientists and engineers are building more and more complex applications to utilize distributed grid resources. The core grid services provide a path for accessing and utilizing these resources in a secure and seamless fashion. However what the scientists need is an environment that will allow them to specify their application runs at a high organizational level, and then support efficient execution across any given set or sets of resources. We have been designing and implementing ScyFlow, a dual-interface architecture (both GUT and APT) that addresses this problem. The scientist/user specifies the application tasks along with the necessary control and data flow, and monitors and manages the execution of the resulting workflow across the distributed resources. In this paper, we utilize two scenarios to provide the details of the two modules of the project, the visual editor and the runtime workflow engine.
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Choudhuri, D.; Banerjee, R.; Srinivasan, S. G.
2017-01-01
The extraordinary creep-resistance of Mg-Nd-based alloys can be correlated to the formation of nanoscale-platelets of β1-Mg3Nd precipitates, that grow along 〈110〉Mg in bulk hcp-Mg and on dislocation lines. The growth kinetics of β1 is sluggish even at high temperatures, and presumably occurs via vacancy migration. However, the rationale for the high-temperature stability of precipitate-matrix interfaces and observed growth direction is unknown, and may likely be related to the interfacial structure and excess energy. Therefore, we study two interfaces– {112}β1/{100}Mg and {111}β1/{110}Mg– that are commensurate with β1/hcp-Mg orientation relationship via first principles calculations. We find that β1 acquires plate-like morphology to reduce small lattice strain via the formation of energetically favorable {112}β1/{100}Mg interfaces, and predict that β1 grows along 〈110〉Mg on dislocation lines due to the migration of metastable {111}β1/{110}Mg. Furthermore, electronic charge distribution of the two interfaces studied here indicated that interfacial-energy of coherent precipitates is sensitive to the population of distorted lattice sites, and their spatial extent in the vicinity of interfaces. Our results have implications for alloy design as they suggest that formation of β1-like precipitates in the hcp-Mg matrix will require well-bonded coherent interface along precipitate broad-faces, while simultaneously destabilizing other interfaces. PMID:28094302
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Bond strength and interface energy between Pd membranes and TiAl supports
NASA Astrophysics Data System (ADS)
Gong, H. R.; He, Y. H.; Huang, B. Y.
2008-09-01
Intermetallic TiAl alloy is proposed as a promising support for Pd membranes. First principles calculations reveal that coherent Pd/TiAl interfaces possess high values of bond strengths. Calculations also show that Ti-terminated (100) Pd/(100) TiAl and (110) Pd/(110) TiAl interfaces are energetically favorable with negative interface energies of about -3.1 J/m2, and that the bond strengths of Pd-Ti are bigger than those of Pd-Al. In addition, densities of states calculations suggest that a stronger chemical bonding is formed in the Pd/TiAl interface than corresponding Pd or TiAl bulks, which agrees well with similar experimental observations in literature.
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Ashraf, Mohammed; Souka, Ahmed; Adelman, Ron A
2017-09-01
To study the effect of the vitreomacular interface on various wet age-related macular degeneration (AMD) characteristics including the size and type of choroidal neovascularization (CNV), choroidal thickness, and activity of the CNV. This was a retrospective observational cross-sectional study. The study included 43 patients (51 eyes) with treatment-naive age-related macular degeneration. Twenty-six patients with wet AMD in one eye and dry AMD in the other eye were included in a paired-eye analysis. Patients underwent optical coherence tomography examination using Heidelberg Spectralis (spectral domain optical coherence tomography) at presentation to determine the type of CNV and the vitreomacular status. In addition, various parameters were measured including the choroidal thickness and horizontal width and vertical height measurements of the CNV. There was no correlation between the height, width, activity or type of the CNV, and the presence or absence of vitreomacular adhesion. The mean choroidal thickness (using enhanced depth imaging) in cases with vitreomacular adhesion was 272.57 μm compared with 197.32 μm in cases with no vitreomacular adhesion, a statistically significant difference (P = 0.003). In the paired-eye study (21 patients), there was no significant difference between the eyes with wet AMD and dry AMD with regard to vitreomacular status or the choroidal thickness. In a subgroup analysis, patients with Type 1 CNV had a significantly higher percentage of vitreomacular adhesion compared with the other eye with dry AMD (P = 0.034). In conclusion, the vitreomacular interface does seem to be associated with an increased choroidal thickness in cases of wet AMD. Furthermore, the association between the vitreomacular interface and wet AMD is more significant for Type 1 CNV.
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Cross-plane thermal conductivity of (Ti,W)N/(Al,Sc)N metal/semiconductor superlattices
NASA Astrophysics Data System (ADS)
Saha, Bivas; Koh, Yee Rui; Comparan, Jonathan; Sadasivam, Sridhar; Schroeder, Jeremy L.; Garbrecht, Magnus; Mohammed, Amr; Birch, Jens; Fisher, Timothy; Shakouri, Ali; Sands, Timothy D.
2016-01-01
Reduction of cross-plane thermal conductivity and understanding of the mechanisms of heat transport in nanostructured metal/semiconductor superlattices are crucial for their potential applications in thermoelectric and thermionic energy conversion devices, thermal management systems, and thermal barrier coatings. We have developed epitaxial (Ti,W)N/(Al,Sc)N metal/semiconductor superlattices with periodicity ranging from 1 nm to 240 nm that show significantly lower thermal conductivity compared to the parent TiN/(Al,Sc)N superlattice system. The (Ti,W)N/(Al,Sc)N superlattices grow with [001] orientation on the MgO(001) substrates with well-defined coherent layers and are nominally single crystalline with low densities of extended defects. Cross-plane thermal conductivity (measured by time-domain thermoreflectance) decreases with an increase in the superlattice interface density in a manner that is consistent with incoherent phonon boundary scattering. Thermal conductivity values saturate at 1.7 W m-1K-1 for short superlattice periods possibly due to a delicate balance between long-wavelength coherent phonon modes and incoherent phonon scattering from heavy tungsten atomic sites and superlattice interfaces. First-principles density functional perturbation theory based calculations are performed to model the vibrational spectrum of the individual component materials, and transport models are used to explain the interface thermal conductance across the (Ti,W)N/(Al,Sc)N interfaces as a function of periodicity. The long-wavelength coherent phonon modes are expected to play a dominant role in the thermal transport properties of the short-period superlattices. Our analysis of the thermal transport properties of (Ti,W)N/(Al,Sc)N metal/semiconductor superlattices addresses fundamental questions about heat transport in multilayer materials.
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Wu, Di; Klaw, Michelle C.; Connors, Theresa; Kholodilov, Nikolai; Burke, Robert E.
2015-01-01
After a spinal cord injury (SCI), CNS axons fail to regenerate, resulting in permanent deficits. This is due to: (1) the presence of inhibitory molecules, e.g., chondroitin sulfate proteoglycans (CSPG), in the glial scar at the lesion; and (2) the diminished growth capacity of adult neurons. We sought to determine whether expressing a constitutively active form of the GTPase Rheb (caRheb) in adult neurons after a complete SCI in rats improves intrinsic growth potential to result in axon regeneration out of a growth-supportive peripheral nerve grafted (PNG) into the SCI cavity. We also hypothesized that treating the glial scar with chondroitinase ABC (ChABC), which digests CSPG, would further allow caRheb-transduced neurons to extend axons across the distal graft interface. We found that targeting this pathway at a clinically relevant post-SCI time point improves both sprouting and regeneration of axons. CaRheb increased the number of axons, but not the number of neurons, that projected into the PNG, indicative of augmented sprouting. We also saw that caRheb enhanced sprouting far rostral to the injury. CaRheb not only increased growth rostral and into the graft, it also resulted in significantly more regrowth of axons across a ChABC-treated scar into caudal spinal cord. CaRheb+ neurons had higher levels of growth-associated-43, suggestive of a newly identified mechanism for mTOR-mediated enhancement of regeneration. Thus, we demonstrate for the first time that simultaneously addressing intrinsic and scar-associated, extrinsic impediments to regeneration results in significant regrowth beyond an extremely challenging, complete SCI site. SIGNIFICANCE STATEMENT After spinal cord injury (SCI), CNS axons fail to regenerate, resulting in permanent deficits. This is due to the diminished growth capacity of adult neurons and the presence of inhibitory molecules in the scar at the lesion. We sought to simultaneously counter both of these obstacles to achieve more robust regeneration after complete SCI. We transduced neurons postinjury to express a constitutively active Rheb to enhance their intrinsic growth potential, transplanted a growth supporting peripheral nerve graft into the lesion cavity, and enzymatically modulated the inhibitory glial scar distal to the graft. We demonstrate, for the first time, that simultaneously addressing neuron-related, intrinsic deficits in axon regrowth and extrinsic, scar-associated impediments to regeneration results in significant regeneration after SCI. PMID:26245968
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Wu, Di; Klaw, Michelle C; Connors, Theresa; Kholodilov, Nikolai; Burke, Robert E; Tom, Veronica J
2015-08-05
After a spinal cord injury (SCI), CNS axons fail to regenerate, resulting in permanent deficits. This is due to: (1) the presence of inhibitory molecules, e.g., chondroitin sulfate proteoglycans (CSPG), in the glial scar at the lesion; and (2) the diminished growth capacity of adult neurons. We sought to determine whether expressing a constitutively active form of the GTPase Rheb (caRheb) in adult neurons after a complete SCI in rats improves intrinsic growth potential to result in axon regeneration out of a growth-supportive peripheral nerve grafted (PNG) into the SCI cavity. We also hypothesized that treating the glial scar with chondroitinase ABC (ChABC), which digests CSPG, would further allow caRheb-transduced neurons to extend axons across the distal graft interface. We found that targeting this pathway at a clinically relevant post-SCI time point improves both sprouting and regeneration of axons. CaRheb increased the number of axons, but not the number of neurons, that projected into the PNG, indicative of augmented sprouting. We also saw that caRheb enhanced sprouting far rostral to the injury. CaRheb not only increased growth rostral and into the graft, it also resulted in significantly more regrowth of axons across a ChABC-treated scar into caudal spinal cord. CaRheb(+) neurons had higher levels of growth-associated-43, suggestive of a newly identified mechanism for mTOR-mediated enhancement of regeneration. Thus, we demonstrate for the first time that simultaneously addressing intrinsic and scar-associated, extrinsic impediments to regeneration results in significant regrowth beyond an extremely challenging, complete SCI site. After spinal cord injury (SCI), CNS axons fail to regenerate, resulting in permanent deficits. This is due to the diminished growth capacity of adult neurons and the presence of inhibitory molecules in the scar at the lesion. We sought to simultaneously counter both of these obstacles to achieve more robust regeneration after complete SCI. We transduced neurons postinjury to express a constitutively active Rheb to enhance their intrinsic growth potential, transplanted a growth supporting peripheral nerve graft into the lesion cavity, and enzymatically modulated the inhibitory glial scar distal to the graft. We demonstrate, for the first time, that simultaneously addressing neuron-related, intrinsic deficits in axon regrowth and extrinsic, scar-associated impediments to regeneration results in significant regeneration after SCI. Copyright © 2015 the authors 0270-6474/15/3511068-13$15.00/0.
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Holographic storage of biphoton entanglement.
Dai, Han-Ning; Zhang, Han; Yang, Sheng-Jun; Zhao, Tian-Ming; Rui, Jun; Deng, You-Jin; Li, Li; Liu, Nai-Le; Chen, Shuai; Bao, Xiao-Hui; Jin, Xian-Min; Zhao, Bo; Pan, Jian-Wei
2012-05-25
Coherent and reversible storage of multiphoton entanglement with a multimode quantum memory is essential for scalable all-optical quantum information processing. Although a single photon has been successfully stored in different quantum systems, storage of multiphoton entanglement remains challenging because of the critical requirement for coherent control of the photonic entanglement source, multimode quantum memory, and quantum interface between them. Here we demonstrate a coherent and reversible storage of biphoton Bell-type entanglement with a holographic multimode atomic-ensemble-based quantum memory. The retrieved biphoton entanglement violates the Bell inequality for 1 μs storage time and a memory-process fidelity of 98% is demonstrated by quantum state tomography.
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NASA Technical Reports Server (NTRS)
Welch, J. D.
1975-01-01
The preliminary design of an experiment for landmark recognition and tracking from the Shuttle/Advanced Technology Laboratory is described. It makes use of parallel coherent optical processing to perform correlation tests between landmarks observed passively with a telescope and previously made holographic matched filters. The experimental equipment including the optics, the low power laser, the random access file of matched filters and the electro-optical readout device are described. A real time optically excited liquid crystal device is recommended for performing the input non-coherent optical to coherent optical interface function. A development program leading to a flight experiment in 1981 is outlined.
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The liquid crystal light valve, an optical-to-optical interface device
NASA Technical Reports Server (NTRS)
Jacobson, A. D.; Beard, T. D.; Bleha, W. P.; Margerum, J. D.; Wong, S. Y.
1972-01-01
A photoactivated liquid crystal light valve is described as an optical-to-optical interface device (OTTO) which is designed to transfer an optical image from a noncoherent light beam to a spatially coherent beam of light, in real time. Schematics of OTTO in use, the liquid cyrstal cell, and the liquid crystal structure are presented. Sensitivity characteristics and the principles of operation are discussed.
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Coherent spin control of a nanocavity-enhanced qubit in diamond
Li, Luozhou; Lu, Ming; Schroder, Tim; ...
2015-01-28
A central aim of quantum information processing is the efficient entanglement of multiple stationary quantum memories via photons. Among solid-state systems, the nitrogen-vacancy centre in diamond has emerged as an excellent optically addressable memory with second-scale electron spin coherence times. Recently, quantum entanglement and teleportation have been shown between two nitrogen-vacancy memories, but scaling to larger networks requires more efficient spin-photon interfaces such as optical resonators. Here we report such nitrogen-vacancy nanocavity systems in strong Purcell regime with optical quality factors approaching 10,000 and electron spin coherence times exceeding 200 µs using a silicon hard-mask fabrication process. This spin-photon interfacemore » is integrated with on-chip microwave striplines for coherent spin control, providing an efficient quantum memory for quantum networks.« less
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Microstructures, mechanical behavior and strengthening mechanism of TiSiCN nanocomposite films
DOE Office of Scientific and Technical Information (OSTI.GOV)
Li, Wei; Liu, Ping; Xue, Zenghui
Recently, the arguments have existed in the strengthening mechanism and microstructural model of the nanocomposite film due to lack of the convincible experimental evidences. In this investigation, the quarternary TiSiCN nanocomposite films with the different C and Si contents are synthesized by the reactive-magnetron-sputtering technique. The TiSiCN film is characterized as the nanocomposite structure with the TiN nanocrystallites surrounded by the (Si 3N 4 + C + CN x) interface phase. When the C/Si content ratio is 2:2, the TiSiCN nanocomposite film is remarkably strengthened with the maximal hardness and elastic modulus of 46.1 GPa and 425 GPa, respectively. Meanwhile,more » the (Si 3N 4 + C + CN x) interfaces exhibit as a crystallized form, which can coordinate the growth misorientations and maintain the coherently epitaxial growth between the TiN nanocrystallites and interfaces. Through the high-resolution transmission electron microscopy (HRTEM) observations, this investigation firstly provides the direct experimental evidence for the crystallized feature of the interfaces when the TiSiCN nanocomposite film is strengthened, suggesting that the strengthening effect of the TiSiCN nanocomposite film can be attributed to the coherent-interface strengthening mechanism, which is expressed as the “nc-TiN/c-Si 3N 4/c-C/c-CN x” model.« less
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Microstructures, mechanical behavior and strengthening mechanism of TiSiCN nanocomposite films
Li, Wei; Liu, Ping; Xue, Zenghui; ...
2017-05-18
Recently, the arguments have existed in the strengthening mechanism and microstructural model of the nanocomposite film due to lack of the convincible experimental evidences. In this investigation, the quarternary TiSiCN nanocomposite films with the different C and Si contents are synthesized by the reactive-magnetron-sputtering technique. The TiSiCN film is characterized as the nanocomposite structure with the TiN nanocrystallites surrounded by the (Si 3N 4 + C + CN x) interface phase. When the C/Si content ratio is 2:2, the TiSiCN nanocomposite film is remarkably strengthened with the maximal hardness and elastic modulus of 46.1 GPa and 425 GPa, respectively. Meanwhile,more » the (Si 3N 4 + C + CN x) interfaces exhibit as a crystallized form, which can coordinate the growth misorientations and maintain the coherently epitaxial growth between the TiN nanocrystallites and interfaces. Through the high-resolution transmission electron microscopy (HRTEM) observations, this investigation firstly provides the direct experimental evidence for the crystallized feature of the interfaces when the TiSiCN nanocomposite film is strengthened, suggesting that the strengthening effect of the TiSiCN nanocomposite film can be attributed to the coherent-interface strengthening mechanism, which is expressed as the “nc-TiN/c-Si 3N 4/c-C/c-CN x” model.« less
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Li, An-Ping; Park, Jewook; Lee, Jaekwang; ...
2014-01-01
Two-dimensional (2D) interfaces between crystalline materials have been shown to generate unusual interfacial electronic states in complex oxides1-4. Recently, a onedimensional (1D) polar-on-nonpolar interface has been realized in hexagonal boron nitride (hBN) and graphene heterostructures 5-10, where a coherent 1D boundary is expected to possess peculiar electronic states dictated by edge states of graphene and the polarity of hBN 11-13. Here we present a combined scanning tunneling microscopy (STM) and firstprinciples theory study of the graphene-hBN boundary to provide a rare glimpse into the spatial and energetic distributions of the 1D boundary states in real-space. The interfaces studied here aremore » crystallographically coherent with sharp transitions from graphene zigzag edges to B (or N) terminated hBN atomic layers on a Cu foil substrate5. The revealed boundary states are about 0.6 eV below or above the Fermi energy depending on the termination of the hBN at the boundary, and are extended along but localized at the boundary with a lateral thickness of 2-3nm. These results suggest that unconventional physical effects similar to those observed at 2D interfaces can also exist in lower dimensions, opening a route for tuning of electronic properties at interfaces in 2D heterostructures.« less
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Coherent beam control through inhomogeneous media in multi-photon microscopy
NASA Astrophysics Data System (ADS)
Paudel, Hari Prasad
Multi-photon fluorescence microscopy has become a primary tool for high-resolution deep tissue imaging because of its sensitivity to ballistic excitation photons in comparison to scattered excitation photons. The imaging depth of multi-photon microscopes in tissue imaging is limited primarily by background fluorescence that is generated by scattered light due to the random fluctuations in refractive index inside the media, and by reduced intensity in the ballistic focal volume due to aberrations within the tissue and at its interface. We built two multi-photon adaptive optics (AO) correction systems, one for combating scattering and aberration problems, and another for compensating interface aberrations. For scattering correction a MEMS segmented deformable mirror (SDM) was inserted at a plane conjugate to the objective back-pupil plane. The SDM can pre-compensate for light scattering by coherent combination of the scattered light to make an apparent focus even at a depths where negligible ballistic light remains (i.e. ballistic limit). This problem was approached by investigating the spatial and temporal focusing characteristics of a broad-band light source through strongly scattering media. A new model was developed for coherent focus enhancement through or inside the strongly media based on the initial speckle contrast. A layer of fluorescent beads under a mouse skull was imaged using an iterative coherent beam control method in the prototype two-photon microscope to demonstrate the technique. We also adapted an AO correction system to an existing in three-photon microscope in a collaborator lab at Cornell University. In the second AO correction approach a continuous deformable mirror (CDM) is placed at a plane conjugate to the plane of an interface aberration. We demonstrated that this "Conjugate AO" technique yields a large field-of-view (FOV) advantage in comparison to Pupil AO. Further, we showed that the extended FOV in conjugate AO is maintained over a relatively large axial misalignment of the conjugate planes of the CDM and the aberrating interface. This dissertation advances the field of microscopy by providing new models and techniques for imaging deeply within strongly scattering tissue, and by describing new adaptive optics approaches to extending imaging FOV due to sample aberrations.
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Automated identification and indexing of dislocations in crystal interfaces
Stukowski, Alexander; Bulatov, Vasily V.; Arsenlis, Athanasios
2012-10-31
Here, we present a computational method for identifying partial and interfacial dislocations in atomistic models of crystals with defects. Our automated algorithm is based on a discrete Burgers circuit integral over the elastic displacement field and is not limited to specific lattices or dislocation types. Dislocations in grain boundaries and other interfaces are identified by mapping atomic bonds from the dislocated interface to an ideal template configuration of the coherent interface to reveal incompatible displacements induced by dislocations and to determine their Burgers vectors. Additionally, the algorithm generates a continuous line representation of each dislocation segment in the crystal andmore » also identifies dislocation junctions.« less
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Yadav, Satyesh Kumar; Shao, S.; Chen, Youxing; ...
2017-10-17
Here, using a newly developed embedded-atom-method potential for Mg–Nb, the semi-coherent Mg/Nb interface with the Kurdjumov–Sachs orientation relationship is studied. Atomistic simulations have been carried out to understand the shear strength of the interface, as well as the interaction between lattice glide dislocations and the interface. The interface shear mechanisms are dependent on the shear loading directions, through either interface sliding between Mg and Nb atomic layers or nucleation and gliding of Shockley partial dislocations in between the first two atomic planes in Mg at the interface. The shear strength for the Mg/Nb interface is found to be generally high,more » in the range of 0.9–1.3 GPa depending on the shear direction. As a consequence, the extents of dislocation core spread into the interface are considerably small, especially when compared to the case of other “weak” interfaces such as the Cu/Nb interface.« less
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A multimedia guide to spinal cord injury: empowerment through self instruction.
Van Biervliet, A; Gest, T R
1995-01-01
The Spinal Cord Injury (SCI) Project is developing a series of instructional modules on SCI that will be distributed via CD-ROM for patient and family education. The modules are based on an instructional program and patient manual distributed by the Paralyzed Veterans of America. The program includes topics ranging from the anatomy and physiology of spinal cord injuries to legal rights established under the Americans With Disabilities Act. The SCI project expands on the instructional manual by combining digital multimedia techniques with motivational features such as games and personal guides. The user selects a personal guide from among a selection of individuals with spinal cord injuries to guide them through tutorials that include accounts of personal experiences. The guides appear in small video windows at various points throughout the tutorials and give personal insight into the topic at hand. The user can also query the other guides to hear their views on a topic. The user interface incorporates 'seamless access' features, which enable persons with a wide range of disabilities to use the program. Innovative features of these modules are the use of personal instructional guides, motivational games and activities, incorporation of alternative input or access strategies, and the use of high quality, low cost, multimedia production strategies.
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Boulesbaa, Abdelaziz; Borguet, Eric
2014-02-06
The dephasing dynamics of a vibrational coherence may reveal the interactions of chemical functional groups with their environment. To investigate this process at a surface, we employ free induction decay sum frequency generation (FID-SFG) to measure the time that it takes for free OH stretch oscillators at the charged (pH ≈ 13, KOH) interface of alumina/water (Al2O3/H2O) to lose their collective coherence. By employing noncollinear optical parametric amplification (NOPA) technology and nonlinear vibrational spectroscopy, we showed that the single free OH peak actually corresponds to two distinct oscillators oriented opposite to each other and measured the total dephasing time, T2, of the free OH stretch modes at the Al2O3/H2O interface with a sub-40 fs temporal resolution. Our results suggested that the free OH oscillators associated with interfacial water dephase on the time scale of 89.4 ± 6.9 fs, whereas the homogeneous dephasing of interfacial alumina hydroxyls is an order of magnitude slower.
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Isolated Spin Qubits in SiC with a High-Fidelity Infrared Spin-to-Photon Interface
NASA Astrophysics Data System (ADS)
Christle, David J.; Klimov, Paul V.; de las Casas, Charles F.; Szász, Krisztián; Ivády, Viktor; Jokubavicius, Valdas; Ul Hassan, Jawad; Syväjärvi, Mikael; Koehl, William F.; Ohshima, Takeshi; Son, Nguyen T.; Janzén, Erik; Gali, Ádám; Awschalom, David D.
2017-04-01
The divacancies in SiC are a family of paramagnetic defects that show promise for quantum communication technologies due to their long-lived electron spin coherence and their optical addressability at near-telecom wavelengths. Nonetheless, a high-fidelity spin-photon interface, which is a crucial prerequisite for such technologies, has not yet been demonstrated. Here, we demonstrate that such an interface exists in isolated divacancies in epitaxial films of 3C-SiC and 4H-SiC. Our data show that divacancies in 4H-SiC have minimal undesirable spin mixing, and that the optical linewidths in our current sample are already similar to those of recent remote entanglement demonstrations in other systems. Moreover, we find that 3C-SiC divacancies have a millisecond Hahn-echo spin coherence time, which is among the longest measured in a naturally isotopic solid. The presence of defects with these properties in a commercial semiconductor that can be heteroepitaxially grown as a thin film on Si shows promise for future quantum networks based on SiC defects.
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On the modified Tabor parameter for the JKR-DMT transition in the presence of a liquid meniscus.
Xu, Dewei; Liechti, Kenneth M; Ravi-Chandar, K
2007-11-15
The JKR, DMT, Maugis models and Tabor parameter for contact under normal loading have been developed based mainly on solid-solid (van der Waals) interactions. In this case, the characteristic length scale for the adhesive forces in the Tabor parameter is the equilibrium interatomic spacing. However, for contact in humid environments, where a liquid meniscus may be present, capillary forces with a longer force range related to the Kelvin radius dominate. Fogden and White [J. Colloid Interface Sci. 138 (1990) 414] introduced a parameter that includes the Kelvin radius for the JKR-DMT transition. This topic was also addressed by Maugis and Gauthier-Manuel [J. Adhes. Sci. Technol. 8 (1994) 1311] who included capillary effects within the frame work that Maugis had previously established. The parameters introduced by Fogden and White and Maugis and Gauthier-Manuel can be viewed as a modified Tabor parameter for the JKR-DMT transition. In the present work, the Kelvin equation linking the Kelvin radius and the relative humidity was explicitly included in the modified Tabor parameter. This provided a quantitative description of the JKR-DMT transition in terms of the relative humidity. This parameter was examined via load and contact radius measurements, where the latter were obtained from Bowden and Tabor's assumption that the friction force f=tauA. The friction experiments were conducted at two different humidity levels using a newly-developed mesoscale friction tester (MFT), which provides a very wide range of contact radii. The modified Tabor parameter was used to reexamine data from pull-off experiments in water and cyclohexane vapor environments [L.R. Fisher, J.N. Israelachvili, Colloids Surf. 3 (1981) 303 and H.K. Christenson, J. Colloid Interface Sci. 121 (1988) 170]. Finally, guidelines are presented for the appropriate choice of contact mechanics models to be used in interpreting data from SFA and AFM experiments in humid environments.
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Assessment of Thermal Dehydration Using the Human Eye: What is the Potential?
2012-01-01
Kenefick a, Neil P. Walsh b, Matthew B. Fortes b, Marieh Esmaeelpour c,d, Samuel N. Cheuvront a,n a US Army Research Institute of Environmental Medicine...anhydrase inhibitors, which are commonly prescribed to glaucoma patients (van der Valk et al., 2005; World Heath Organization; 2009). Both types of...Deposition and thinning of the human tear film. J. Colloid Interface Sci. 184, 44–51. World Heath Organization, 2009. WHO model formulary 2008. WHO
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Halder, Sebastian; Takano, Kouji; Ora, Hiroki; Onishi, Akinari; Utsumi, Kota; Kansaku, Kenji
2016-01-01
Gaze-independent brain-computer interfaces (BCIs) are a possible communication channel for persons with paralysis. We investigated if it is possible to use auditory stimuli to create a BCI for the Japanese Hiragana syllabary, which has 46 Hiragana characters. Additionally, we investigated if training has an effect on accuracy despite the high amount of different stimuli involved. Able-bodied participants (N = 6) were asked to select 25 syllables (out of fifty possible choices) using a two step procedure: First the consonant (ten choices) and then the vowel (five choices). This was repeated on 3 separate days. Additionally, a person with spinal cord injury (SCI) participated in the experiment. Four out of six healthy participants reached Hiragana syllable accuracies above 70% and the information transfer rate increased from 1.7 bits/min in the first session to 3.2 bits/min in the third session. The accuracy of the participant with SCI increased from 12% (0.2 bits/min) to 56% (2 bits/min) in session three. Reliable selections from a 10 × 5 matrix using auditory stimuli were possible and performance is increased by training. We were able to show that auditory P300 BCIs can be used for communication with up to fifty symbols. This enables the use of the technology of auditory P300 BCIs with a variety of applications. PMID:27746716
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Halder, Sebastian; Takano, Kouji; Ora, Hiroki; Onishi, Akinari; Utsumi, Kota; Kansaku, Kenji
2016-01-01
Gaze-independent brain-computer interfaces (BCIs) are a possible communication channel for persons with paralysis. We investigated if it is possible to use auditory stimuli to create a BCI for the Japanese Hiragana syllabary, which has 46 Hiragana characters. Additionally, we investigated if training has an effect on accuracy despite the high amount of different stimuli involved. Able-bodied participants ( N = 6) were asked to select 25 syllables (out of fifty possible choices) using a two step procedure: First the consonant (ten choices) and then the vowel (five choices). This was repeated on 3 separate days. Additionally, a person with spinal cord injury (SCI) participated in the experiment. Four out of six healthy participants reached Hiragana syllable accuracies above 70% and the information transfer rate increased from 1.7 bits/min in the first session to 3.2 bits/min in the third session. The accuracy of the participant with SCI increased from 12% (0.2 bits/min) to 56% (2 bits/min) in session three. Reliable selections from a 10 × 5 matrix using auditory stimuli were possible and performance is increased by training. We were able to show that auditory P300 BCIs can be used for communication with up to fifty symbols. This enables the use of the technology of auditory P300 BCIs with a variety of applications.
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Disorder-controlled superconductivity at YBa2Cu3O7/SrTiO3 interfaces
NASA Astrophysics Data System (ADS)
Garcia-Barriocanal, J.; Perez-Muñoz, A. M.; Sefrioui, Z.; Arias, D.; Varela, M.; Leon, C.; Pennycook, S. J.; Santamaria, J.
2013-06-01
We examine the effect of interface disorder in suppressing superconductivity in coherently grown ultrathin YBa2Cu3O7 (YBCO) layers on SrTiO3 (STO) in YBCO/STO superlattices. The termination plane of the STO is TiO2 and the CuO chains are missing at the interface. Disorder (steps) at the STO interface cause alterations of the stacking sequence of the intracell YBCO atomic layers. Stacking faults give rise to antiphase boundaries which break the continuity of the CuO2 planes and depress superconductivity. We show that superconductivity is directly controlled by interface disorder outlining the importance of pair breaking and localization by disorder in ultrathin layers.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Pigozzi, Giancarlo; Janczak-Rusch, Jolanta; Passerone, Daniele
2012-10-29
Nano-sized Ag-Cu{sub 8nm}/AlN{sub 10nm} multilayers were deposited by reactive DC sputtering on {alpha}-Al{sub 2}O{sub 3}(0001) substrates. Investigation of the phase constitution and interface structure of the multilayers evidences a phase separation of the alloy sublayers into nanosized grains of Ag and Cu. The interfaces between the Ag grains and the quasi-single-crystalline AlN sublayers are semi-coherent, whereas the corresponding Cu/AlN interfaces are incoherent. The orientation relationship between Ag and AlN is constant throughout the entire multilayer stack. These observations are consistent with atomistic models of the interfaces as obtained by ab initio calculations.
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Morphological characterization of dental prostheses interfaces using optical coherence tomography
NASA Astrophysics Data System (ADS)
Sinescu, Cosmin; Negrutiu, Meda L.; Ionita, Ciprian; Marsavina, Liviu; Negru, Radu; Caplescu, Cristiana; Bradu, Adrian; Topala, Florin; Rominu, Roxana O.; Petrescu, Emanuela; Leretter, Marius; Rominu, Mihai; Podoleanu, Adrian G.
2010-03-01
Fixed partial prostheses as integral ceramic, polymers, metal-ceramic or metal-polymers bridges are mainly used in the frontal part of the dental arch (especially the integral bridges). They have to satisfy high stress as well as esthetic requirements. The masticatory stress may induce fractures of the bridges. These may be triggered by initial materials defects or by alterations of the technological process. The fractures of these bridges lead to functional, esthetic and phonetic disturbances which finally render the prosthetic treatment inefficient. Dental interfaces represent one of the most significant aspects in the strength of the dental prostheses under the masticatory load. The purpose of this study is to evaluate the capability of optical coherence tomography (OCT) to characterize the dental prostheses interfaces. The materials used were several fixed partial prostheses integral ceramic, polymers, metal-ceramic and metal-polymers bridges. It is important to produce both C-scans and B-scans of the defects in order to differentiate morphological aspects of the bridge infrastructures. The material defects observed with OCT were investigated with micro-CT in order to prove their existence and positions. In conclusion, it is important to have a non invasive method to investigate dental prostheses interfaces before the insertion of prostheses in the oral cavity.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Berginc, G
2013-11-30
We have developed a general formalism based on Green's functions to calculate the coherent electromagnetic field scattered by a random medium with rough boundaries. The approximate expression derived makes it possible to determine the effective permittivity, which is generalised for a layer of an inhomogeneous random medium with different types of particles and bounded with randomly rough interfaces. This effective permittivity describes the coherent propagation of an electromagnetic wave in a random medium with randomly rough boundaries. We have obtained an expression, which contains the Maxwell – Garnett formula at the low-frequency limit, and the Keller formula; the latter hasmore » been proved to be in good agreement with experiments for particles whose dimensions are larger than a wavelength. (coherent light scattering)« less
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Two modes of grain boundary pinning by coherent precipitates
Wang, Nan; Ji, Yanzhou; Wang, Yongbiao; ...
2017-06-18
Here, we propose a two-mechanism theory to estimate the pinning effect of coherent precipitates on grain-boundary (GB) migration in grain growth, taking into account the important effect of elastic misfit strain at the coherent interface. Depending on the relative importance of the elastic and the GB contributions to the total free energy, Zener type stabilization or a novel elastic energy induced stabilization may occur. It is found that the pinning is most effective in the crossover region between these two mechanisms. Finally, a phase-field-crystal model is used to numerically validate the theory. Relevant experiments and potential impacts on alloy designmore » are also discussed.« less
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Voltage tunability of thermal conductivity in ferroelectric materials
Ihlefeld, Jon; Hopkins, Patrick Edward
2016-02-09
A method to control thermal energy transport uses mobile coherent interfaces in nanoscale ferroelectric films to scatter phonons. The thermal conductivity can be actively tuned, simply by applying an electrical potential across the ferroelectric material and thereby altering the density of these coherent boundaries to directly impact thermal transport at room temperature and above. The invention eliminates the necessity of using moving components or poor efficiency methods to control heat transfer, enabling a means of thermal energy control at the micro- and nano-scales.
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Ray-optical theory of broadband partially coherent emission
NASA Astrophysics Data System (ADS)
Epstein, Ariel; Tessler, Nir; Einziger, Pinchas D.
2013-04-01
We present a rigorous formulation of the effects of spectral broadening on emission of partially coherent source ensembles embedded in multilayered formations with arbitrarily shaped interfaces, provided geometrical optics is valid. The resulting ray-optical theory, applicable to a variety of optical systems from terahertz lenses to photovoltaic cells, quantifies the fundamental interplay between bandwidth and layer dimensions, and sheds light on common practices in optical analysis of statistical fields, e.g., disregarding multiple reflections or neglecting interference cross terms.
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Analysis of biosurfaces by neutron reflectometry: From simple to complex interfaces
Junghans, Ann; Watkins, Erik B.; Barker, Robert D.; ...
2015-03-16
Because of its high sensitivity for light elements and the scattering contrast manipulation via isotopic substitutions, neutron reflectometry (NR) is an excellent tool for studying the structure of soft-condensed material. These materials include model biophysical systems as well as in situ living tissue at the solid–liquid interface. The penetrability of neutrons makes NR suitable for probing thin films with thicknesses of 5–5000 Å at various buried, for example, solid–liquid, interfaces [J. Daillant and A. Gibaud, Lect. Notes Phys. 770, 133 (2009); G. Fragneto-Cusani, J. Phys.: Condens. Matter 13, 4973 (2001); J. Penfold, Curr. Opin. Colloid Interface Sci. 7, 139 (2002)].more » Over the past two decades, NR has evolved to become a key tool in the characterization of biological and biomimetic thin films. Highlighted In the current report are some of the authors' recent accomplishments in utilizing NR to study highly complex systems, including in-situ experiments. Such studies will result in a much better understanding of complex biological problems, have significant medical impact by suggesting innovative treatment, and advance the development of highly functionalized biomimetic materials.« less
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Partially coherent surface plasmon modes
NASA Astrophysics Data System (ADS)
Niconoff, G. M.; Vara, P. M.; Munoz-Lopez, J.; Juárez-Morales, J. C.; Carbajal-Dominguez, A.
2011-04-01
Elementary long-range plasmon modes are described assuming an exponential dependence of the refractive index in the neighbourhood of the interface dielectric-metal thin film. The study is performed using coupling mode theory. The interference between two long-range plasmon modes generated that way allows the synthesis of surface sinusoidal plasmon modes, which can be considered as completely coherent generalized plasmon modes. These sinusoidal plasmon modes are used for the synthesis of new partially coherent surface plasmon modes, which are obtained by means of an incoherent superposition of sinusoidal plasmon modes where the period of each one is considered as a random variable. The kinds of surface modes generated have an easily tuneable profile controlled by means of the probability density function associated to the period. We show that partially coherent plasmon modes have the remarkable property to control the length of propagation which is a notable feature respect to the completely coherent surface plasmon mode. The numerical simulation for sinusoidal, Bessel, Gaussian and Dark Hollow plasmon modes are presented.
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All-optical control of long-lived nuclear spins in rare-earth doped nanoparticles.
Serrano, D; Karlsson, J; Fossati, A; Ferrier, A; Goldner, P
2018-05-29
Nanoscale systems that coherently couple to light and possess spins offer key capabilities for quantum technologies. However, an outstanding challenge is to preserve properties, and especially optical and spin coherence lifetimes, at the nanoscale. Here, we report optically controlled nuclear spins with long coherence lifetimes (T 2 ) in rare-earth-doped nanoparticles. We detect spins echoes and measure a spin coherence lifetime of 2.9 ± 0.3 ms at 5 K under an external magnetic field of 9 mT, a T 2 value comparable to those obtained in bulk rare-earth crystals. Moreover, we achieve spin T 2 extension using all-optical spin dynamical decoupling and observe high fidelity between excitation and echo phases. Rare-earth-doped nanoparticles are thus the only nano-material in which optically controlled spins with millisecond coherence lifetimes have been reported. These results open the way to providing quantum light-atom-spin interfaces with long storage time within hybrid architectures.
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Bone regeneration assessment by optical coherence tomography and MicroCT synchrotron radiation
NASA Astrophysics Data System (ADS)
Negrutiu, Meda L.; Sinescu, Cosmin; Canjau, Silvana; Manescu, Adrian; Topalá, Florin I.; Hoinoiu, Bogdan; Romînu, Mihai; Márcáuteanu, Corina; Duma, Virgil; Bradu, Adrian; Podoleanu, Adrian G.
2013-06-01
Bone grafting is a commonly performed surgical procedure to augment bone regeneration in a variety of orthopaedic and maxillofacial procedures, with autologous bone being considered as the "gold standard" bone-grafting material, as it combines all properties required in a bone-graft material: osteoinduction (bone morphogenetic proteins - BMPs - and other growth factors), osteogenesis (osteoprogenitor cells) and osteoconduction (scaffold). The problematic elements of bone regenerative materials are represented by their quality control methods, the adjustment of the initial bone regenerative material, the monitoring (noninvasive, if possible) during their osteoconduction and osteointegration period and biomedical evaluation of the new regenerated bone. One of the research directions was the interface investigation of the regenerative bone materials and their behavior at different time periods on the normal femoral rat bone. 12 rat femurs were used for this investigation. In each ones a 1 mm diameter hole were drilled and a bone grafting material was inserted in the artificial defect. The femurs were removed after one, three and six months. The defects repaired by bone grafting material were evaluated by optical coherence tomography working in Time Domain Mode at 1300 nm. Three dimensional reconstructions of the interfaces were generated. The validations of the results were evaluated by microCT. Synchrotron Radiation allows achieving high spatial resolution images to be generated with high signal-to-noise ratio. In addition, Synchrotron Radiation allows acquisition of volumes at different energies and volume subtraction to enhance contrast. Evaluation of the bone grafting material/bone interface with noninvasive methods such as optical coherence tomography could act as a valuable procedure that can be use in the future in the usual clinical techniques. The results were confirmed by microCT. Optical coherence tomography can be performed in vivo and can provide a qualitative and quantitative evaluation of the bone augmentation procedure.
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Structure of the airflow above surface waves
NASA Astrophysics Data System (ADS)
Buckley, Marc; Veron, Fabrice
2016-04-01
Weather, climate and upper ocean patterns are controlled by the exchanges of momentum, heat, mass, and energy across the ocean surface. These fluxes are, in turn, influenced by the small-scale physics at the wavy air-sea interface. We present laboratory measurements of the fine-scale airflow structure above waves, achieved in over 15 different wind-wave conditions, with wave ages Cp/u* ranging from 1.4 to 66.7 (where Cp is the peak phase speed of the waves, and u* the air friction velocity). The experiments were performed in the large (42-m long) wind-wave-current tank at University of Delaware's Air-Sea Interaction laboratory (USA). A combined Particle Image Velocimetry and Laser Induced Fluorescence system was specifically developed for this study, and provided two-dimensional airflow velocity measurement as low as 100 um above the air-water interface. Starting at very low wind speeds (U10~2m/s), we directly observe coherent turbulent structures within the buffer and logarithmic layers of the airflow above the air-water interface, whereby low horizontal velocity air is ejected away from the surface, and higher velocity fluid is swept downward. Wave phase coherent quadrant analysis shows that such turbulent momentum flux events are wave-phase dependent. Airflow separation events are directly observed over young wind waves (Cp/u*<3.7) and counted using measured vorticity and surface viscous stress criteria. Detached high spanwise vorticity layers cause intense wave-coherent turbulence downwind of wave crests, as shown by wave-phase averaging of turbulent momentum fluxes. Mean wave-coherent airflow motions and fluxes also show strong phase-locked patterns, including a sheltering effect, upwind of wave crests over old mechanically generated swells (Cp/u*=31.7), and downwind of crests over young wind waves (Cp/u*=3.7). Over slightly older wind waves (Cp/u* = 6.5), the measured wave-induced airflow perturbations are qualitatively consistent with linear critical layer theory.
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SciFlo: Semantically-Enabled Grid Workflow for Collaborative Science
NASA Astrophysics Data System (ADS)
Yunck, T.; Wilson, B. D.; Raskin, R.; Manipon, G.
2005-12-01
SciFlo is a system for Scientific Knowledge Creation on the Grid using a Semantically-Enabled Dataflow Execution Environment. SciFlo leverages Simple Object Access Protocol (SOAP) Web Services and the Grid Computing standards (WS-* standards and the Globus Alliance toolkits), and enables scientists to do multi-instrument Earth Science by assembling reusable SOAP Services, native executables, local command-line scripts, and python codes into a distributed computing flow (a graph of operators). SciFlo's XML dataflow documents can be a mixture of concrete operators (fully bound operations) and abstract template operators (late binding via semantic lookup). All data objects and operators can be both simply typed (simple and complex types in XML schema) and semantically typed using controlled vocabularies (linked to OWL ontologies such as SWEET). By exploiting ontology-enhanced search and inference, one can discover (and automatically invoke) Web Services and operators that have been semantically labeled as performing the desired transformation, and adapt a particular invocation to the proper interface (number, types, and meaning of inputs and outputs). The SciFlo client & server engines optimize the execution of such distributed data flows and allow the user to transparently find and use datasets and operators without worrying about the actual location of the Grid resources. The scientist injects a distributed computation into the Grid by simply filling out an HTML form or directly authoring the underlying XML dataflow document, and results are returned directly to the scientist's desktop. A Visual Programming tool is also being developed, but it is not required. Once an analysis has been specified for a granule or day of data, it can be easily repeated with different control parameters and over months or years of data. SciFlo uses and preserves semantics, and also generates and infers new semantic annotations. Specifically, the SciFlo engine uses semantic metadata to understand (infer) what it is doing and potentially improve the data flow; preserves semantics by saving links to the semantics of (metadata describing) the input datasets, related datasets, and the data transformations (algorithms) used to generate downstream products; generates new metadata by allowing the user to add semantic annotations to the generated data products (or simply accept automatically generated provenance annotations); and infers new semantic metadata by understanding and applying logic to the semantics of the data and the transformations performed. Much ontology development still needs to be done but, nevertheless, SciFlo documents provide a substrate for using and preserving more semantics as ontologies develop. We will give a live demonstration of the growing SciFlo network using an example dataflow in which atmospheric temperature and water vapor profiles from three Earth Observing System (EOS) instruments are retrieved using SOAP (geo-location query & data access) services, co-registered, and visually & statistically compared on demand (see http://sciflo.jpl.nasa.gov for more information).
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D'Aguanno, Giuseppe; Mattiucci, Nadia; Bloemer, Mark J; Scalora, Michael
2006-03-01
We predict a large enhancement of interface second-harmonic generation near the zero-n(-) gap of a Bragg grating made of alternating layers of negative- and positive-index materials. Field localization and coherent oscillations of the nonlinear dipoles located at the structure's interfaces conspire to yield conversion efficiencies at least an order of magnitude greater than those achievable in the same length of nonlinear, phase-matched bulk material. These findings thus point to a new class of second-harmonic-generation devices made of standard centrosymmetric materials.
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Size Dependent Mechanical Behavior of Free-Standing Glassy Polymer Thin Films
2014-08-31
thickness is less than 20 ( ) 1 ( / ) bulk film E EE h hδ = + 14 nm using the liquid dewetting method. Additionally, earlier studies by McKenna’s group and...coated substrates: Rupture, dewetting , and drop formation. J. Colloid Interface Sci. 178(2), 383 (1996). 8. C.B. Roth and J.R. Dutcher: Glass transition...Phys. J. E. 20(2), 143 (2006). 31. J. Wang and G.B. McKenna: Viscoelastic and Glass Transition Properties of Ultrathin Polystyrene Films by Dewetting
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A Model for the Interfacial Kinetics of Phospholipase D Activity on Long-Chain Lipids
2013-07-01
we extend this model to account for the interaction between PLD and its reaction product, phosphatidic acid (PA), which is a long-chain lipid and... phosphatidic acid , and lecithin/ phosphatidic acid fixed monolayers: a Langmuit film balance study. J. Colloid Interface Sci. 79:319–338. 55. Morris, A...Dennis. 1988. Kinetic analysis of the Ca2þ-dependent, membrane-bound, macrophage phospholipase A2 and the effects of arachidonic acid . J. Biol. Chem. 263
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1988-03-01
Results, ATR-86A(8501)-1, The Aerospace Corporation: El Segundo, Calif. (20 May 1987). 3. D. Neaman , W. Shedd, and B. Buchanan, "Permanently Ionizing...Radiation Effects in Dielectrically Bounded Field-Effect Transistors," IEEE Trans.. Nucl. Sci. NS-20 [6], 158-165 (Decembe. 1973). 4. D. Neaman , W. Shedd...1974). 5. D. Neaman , W. Shedd, and B. Buchanan, "Silicon-Sapphire Interface Charge Trapping -- Effects of Sapphire Type and Epi Growth Conditions
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2016-10-01
pressures and increased blood flow. This level of off-loading is achieved by postural changes during sustained reaching, leaning and other...wheelchair cushions and pressure relief maneuvers on ischial interface pressure and blood flow in people with spinal cord injury”, Archives of Physical Medicine and Rehabilitation, Vol. 95 no.7, pp. 1350-1357, July 2014. ...0 AWARD NUMBER: W81XWH-13-1-0387 TITLE: Pressure Relief Behaviors and Weight-Shifting Activities to Prevent Pressure Ulcers in
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Microemulsion-Type Fire-Resistant Diesel Fuel.
1984-12-31
Interface Sci., 42, 381 (1983). (SPEC22.A) 76 V. REFERENCES 1. Weatherford, W.D., Jr.; Fodor, G.E.; Naegeli , D.W.; Owens, E.C.; and Wright, B.R.; and...OO01 and DAAK70-80-C-OOOI, Report AFLRL No. il, December 1979 (Government Accession No. AD A083610). 2. Weatherford, W.D., Jr.; Fodor, G.E.; Naegeli , D.W...130, September 1980 (Government Accession No. AD A090129). 4. Weatherford, W.D., Jr.; Fodor, G.E.; Kanakia, M.D.; Naegeli , D.W.; and Wright, B.R
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1981-11-01
and the cyclohexane over molecular sieves, -79- pm NO pAalB hION fl i4a and then measuring the ppm of water in the cyclohexane using the Karl Fischer ... potentiometric titration using a method outlined by Bell [J. Polymer Sci. 8, 417-36 (1970)]. The procedure for epoxy groups involves the re- action with...with time, earliest stages of coating delamination, and secondary processes that occur was obtained by time lapse photography. Electrical methods are
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High-Temperature Ceramic Superconductors
1990-01-10
the solution was stable for several weeks. 3-1 Barium 2-(2-ethoxyethoxy)ethoxide was prepared by reaction of barium metal granules (Alfa inorganics ...1977). 3. Ottewill, R. H., "Stability and Instability in Disperse Systems," J. Colloid Interface Sci., 58, 357-373 (1977). 4. Hamaker , H. C., Physics...given by (Ref. 4) A / 2 2 2a2 r2 +a\\ r + n 2 ) (2) A-i where A, the Hamaker constant, depends on the properties of the parti- cles and the
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Influence of CdS nanoparticles grain morphology on laser-induced absorption
NASA Astrophysics Data System (ADS)
Ebothé, Jean; Michel, Jean; Kityk, I. V.; Lakshminarayana, G.; Yanchuk, O. M.; Marchuk, O. V.
2018-06-01
Using external illumination of a 7 nanosecond (ns) doubled frequency Nd: YAG laser emitting at λ = 532 nm with frequency repetition 10 Hz it was established a possibility of significant changes of the absorption at the probing wavelength 1150 nm of continuous wave (cw) He-Ne laser for the CdS nanoparticles embedded into the PVA polymer matrix. The effect is observed only during the two beam laser coherent treatment and this effect is a consequence of interference of two coherent beams. It is shown a principal role of the grain morphology in the efficiency of the process, which is more important than the nanoparticle sizes. The photoinduced absorption is manifested in the space distribution of the probing laser beam. The principal role of the grain interfaces between the nanoparticle interfaces and the surrounding polymer matrix is shown. The effect is almost independent of the nanoparticle sizes. It may be used for laser operation by nanocomposites.
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Perfect absorption in nanotextured thin films via Anderson-localized photon modes
NASA Astrophysics Data System (ADS)
Aeschlimann, Martin; Brixner, Tobias; Differt, Dominik; Heinzmann, Ulrich; Hensen, Matthias; Kramer, Christian; Lükermann, Florian; Melchior, Pascal; Pfeiffer, Walter; Piecuch, Martin; Schneider, Christian; Stiebig, Helmut; Strüber, Christian; Thielen, Philip
2015-10-01
The enhancement of light absorption in absorber layers is crucial in a number of applications, including photovoltaics and thermoelectrics. The efficient use of natural resources and physical constraints such as limited charge extraction in photovoltaic devices require thin but efficient absorbers. Among the many different strategies used, light diffraction and light localization at randomly nanotextured interfaces have been proposed to improve absorption. Although already exploited in commercial devices, the enhancement mechanism for devices with nanotextured interfaces is still subject to debate. Using coherent two-dimensional nanoscopy and coherent light scattering, we demonstrate the existence of localized photonic states in nanotextured amorphous silicon layers as used in commercial thin-film solar cells. Resonant absorption in these states accounts for the enhanced absorption in the long-wavelength cutoff region. Our observations establish that Anderson localization—that is, strong localization—is a highly efficient resonant absorption enhancement mechanism offering interesting opportunities for the design of efficient future absorber layers.
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Optical coherence of 166Er:7LiYF4 crystal below 1 K
NASA Astrophysics Data System (ADS)
Kukharchyk, N.; Sholokhov, D.; Morozov, O.; Korableva, S. L.; Kalachev, A. A.; Bushev, P. A.
2018-02-01
We explore optical coherence and spin dynamics of an isotopically purified 166Er:7LiYF4 crystal below 1 K and at weak magnetic fields < 0.3T. Crystals were grown in our lab and demonstrate narrow inhomogeneous optical broadening down to 16 MHz. Solid-state atomic ensembles with such narrow linewidths are very attractive for implementing of off-resonant Raman quantum memory and for the interfacing of superconducting quantum circuits and telecom C-band optical photons. Both applications require a low magnetic field of ∼10 mT. However, at conventional experimental temperatures T > 1.5 K, optical coherence of Er:LYF crystal attains ≃ 10 μ {{s}} time scale only at strong magnetic fields above 1.5 T. In the present work, we demonstrate that the deep freezing of Er:LYF crystal below 1 K results in the increase of optical coherence time to ≃ 100 μ {{s}} at weak fields.
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NASA Astrophysics Data System (ADS)
Garland, N. A.; Boyle, G. J.; Cocks, D. G.; White, R. D.
2018-02-01
This study reviews the neutral density dependence of electron transport in gases and liquids and develops a method to determine the nonlinear medium density dependence of electron transport coefficients and scattering rates required for modeling transport in the vicinity of gas-liquid interfaces. The method has its foundations in Blanc’s law for gas-mixtures and adapts the theory of Garland et al (2017 Plasma Sources Sci. Technol. 26) to extract electron transport data across the gas-liquid transition region using known data from the gas and liquid phases only. The method is systematically benchmarked against multi-term Boltzmann equation solutions for Percus-Yevick model liquids. Application to atomic liquids highlights the utility and accuracy of the derived method.
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MONTE: the next generation of mission design and navigation software
NASA Astrophysics Data System (ADS)
Evans, Scott; Taber, William; Drain, Theodore; Smith, Jonathon; Wu, Hsi-Cheng; Guevara, Michelle; Sunseri, Richard; Evans, James
2018-03-01
The Mission analysis, Operations and Navigation Toolkit Environment (MONTE) (Sunseri et al. in NASA Tech Briefs 36(9), 2012) is an astrodynamic toolkit produced by the Mission Design and Navigation Software Group at the Jet Propulsion Laboratory. It provides a single integrated environment for all phases of deep space and Earth orbiting missions. Capabilities include: trajectory optimization and analysis, operational orbit determination, flight path control, and 2D/3D visualization. MONTE is presented to the user as an importable Python language module. This allows a simple but powerful user interface via CLUI or script. In addition, the Python interface allows MONTE to be used seamlessly with other canonical scientific programming tools such as SciPy, NumPy, and Matplotlib. MONTE is the prime operational orbit determination software for all JPL navigated missions.
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Precipitation of coherent Ni{sub 2}(Cr, W) superlattice in an Ni–Cr–W superalloy
DOE Office of Scientific and Technical Information (OSTI.GOV)
Gao, Xiangyu; Hu, Rui, E-mail: rhu@nwpu.edu.cn; Zhang, Tiebang
2016-01-15
It is demonstrated that a nanometer-sized Ni{sub 2}(Cr, W) superlattice with a Pt{sub 2}Mo-type structure can precipitate in an Ni–Cr–W alloy by means of a simple aging treatment at 550 °C. The dark-field image of short-range order domains has been found for the first time experimentally. The mechanism of short-range order to long-range order transformation has been revealed based on transmission electron microscopy result and static concentration waves theory and found to be continuous ordering. The randomness of the transformation of static concentration waves leads to equiprobable occurrence of the different variants. The transformation of short-range order to long-range ordermore » gives rise to the Pt{sub 2}Mo-type Ni{sub 2}(Cr, W) superlattice. The interfaces between Ni{sub 2}(Cr, W) and Ni-based matrix and the different variants of Ni{sub 2}(Cr, W) have been investigated by high resolution transmission electron microscopy. The results reveal that the interfaces between Ni{sub 2}(Cr, W) and surrounding matrix are coherent at the atomic scale. - Highlights: • The DF image of SRO cluster has been found for the first time experimentally. • The transformation of SRO to LRO gives rise to the Pt{sub 2}Mo-type Ni{sub 2}(Cr, W). • Variants of Ni{sub 2}(Cr, W) occur equiprobably. • The interfaces between Ni{sub 2}(Cr, W) and matrix are coherent at the atomic scale.« less
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A hierarchically distributed architecture for fault isolation expert systems on the space station
NASA Technical Reports Server (NTRS)
Miksell, Steve; Coffer, Sue
1987-01-01
The Space Station Axiomatic Fault Isolating Expert Systems (SAFTIES) system deals with the hierarchical distribution of control and knowledge among independent expert systems doing fault isolation and scheduling of Space Station subsystems. On its lower level, fault isolation is performed on individual subsystems. These fault isolation expert systems contain knowledge about the performance requirements of their particular subsystem and corrective procedures which may be involved in repsonse to certain performance errors. They can control the functions of equipment in their system and coordinate system task schedules. On a higher level, the Executive contains knowledge of all resources, task schedules for all systems, and the relative priority of all resources and tasks. The executive can override any subsystem task schedule in order to resolve use conflicts or resolve errors that require resources from multiple subsystems. Interprocessor communication is implemented using the SAFTIES Communications Interface (SCI). The SCI is an application layer protocol which supports the SAFTIES distributed multi-level architecture.
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Advances in Data Management in Remote Sensing and Climate Modeling
NASA Astrophysics Data System (ADS)
Brown, P. G.
2014-12-01
Recent commercial interest in "Big Data" information systems has yielded little more than a sense of deja vu among scientists whose work has always required getting their arms around extremely large databases, and writing programs to explore and analyze it. On the flip side, there are some commercial DBMS startups building "Big Data" platform using techniques taken from earth science, astronomy, high energy physics and high performance computing. In this talk, we will introduce one such platform; Paradigm4's SciDB, the first DBMS designed from the ground up to combine the kinds of quality-of-service guarantees made by SQL DBMS platforms—high level data model, query languages, extensibility, transactions—with the kinds of functionality familiar to scientific users—arrays as structural building blocks, integrated linear algebra, and client language interfaces that minimize the learning curve. We will review how SciDB is used to manage and analyze earth science data by several teams of scientific users.
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NASA Technical Reports Server (NTRS)
Rilee, Michael Lee; Kuo, Kwo-Sen
2017-01-01
The SpatioTemporal Adaptive Resolution Encoding (STARE) is a unifying scheme encoding geospatial and temporal information for organizing data on scalable computing/storage resources, minimizing expensive data transfers. STARE provides a compact representation that turns set-logic functions into integer operations, e.g. conditional sub-setting, taking into account representative spatiotemporal resolutions of the data in the datasets. STARE geo-spatiotemporally aligns data placements of diverse data on massive parallel resources to maximize performance. Automating important scientific functions (e.g. regridding) and computational functions (e.g. data placement) allows scientists to focus on domain-specific questions instead of expending their efforts and expertise on data processing. With STARE-enabled automation, SciDB (Scientific Database) plus STARE provides a database interface, reducing costly data preparation, increasing the volume and variety of interoperable data, and easing result sharing. Using SciDB plus STARE as part of an integrated analysis infrastructure dramatically eases combining diametrically different datasets.
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α-Al2O3/Ga2O3 superlattices coherently grown on r-plane sapphire
NASA Astrophysics Data System (ADS)
Oshima, Takayoshi; Kato, Yuji; Imura, Masataka; Nakayama, Yoshiko; Takeguchi, Masaki
2018-06-01
Ten-period binary α-Al2O3/Ga2O3 superlattices were fabricated on r-plane sapphire substrates by molecular beam epitaxy. By systematic variation of α-Ga2O3 thickness and evaluation through X-ray reflectivity and diffraction measurements and scanning transmission electron microscopy, we verified that the superlattice with α-Ga2O3 thickness up to ∼1 nm had coherent interfaces without misfit dislocation in spite of the large lattice mismatches. This successful fabrication of coherent α-Al2O3/Ga2O3 superlattices will encourage further development of α-(Al x Ga1‑ x )2O3-based heterostructures including superlattices.
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NASA Astrophysics Data System (ADS)
Li, Zhi-Xin; Cao, Jin-Jin; Gou, Xiao-Fan; Wang, Tian-Ge; Xue, Feng
2018-01-01
We report a discovery of the quasi-two-dimensional (quasi-2D) CuO2 plane between the superconductor YBa2Cu3O7 (YBCO) and CeO2 buffer layer (mostly used in the fabrication) of coated conductors through the atomistic computer simulations with the molecular dynamics (MD) and first-principle calculations. For an YBCO coated conductor with multilayer structures, the buffer layers deposited onto a substrate are mainly considered to transfer a strong biaxial texture from the substrate to the YBCO layer. To deeply understand the tuning mechanism of the texture transfer, exploring the complete atomic-level picture of the structure between the YBa2Cu3O7/CeO2 interfaces is firstly required. However, the related observation data have not been available due to some big challenges of experimental techniques. With the MD simulations, having tested the accuracy of the potential functions for the YBa2Cu3O7/CeO2 interface, we constructed a total of 54 possible atom stacking models of the interface and identified its most appropriate and stable structure according to the criterion of the interface adhesion energy and the coherent characterization. To further verify the stability of the identified structure, we performed the first-principle calculations to obtain the adhesion energy and developed the general knowledge of the interface structure. Finally, a coherent interface formed with a new built quasi-2D CuO2 plane that is structurally similar to the CuO2 plane inside bulk YBCO was determined.
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NASA Astrophysics Data System (ADS)
Rusu, Laura-Cristina; Negrutiu, Meda Lavinia; Sinescu, Cosmin; Hoinoiu, Bogdan; Zaharia, Cristian; Ardelean, Lavinia; Duma, Virgil-Florin; Podoleanu, Adrian G.
2014-01-01
The osteoconductive materials are important in bone regeneration procedures. Three dimensional (3D) reconstructions were obtained from the analysis. The aim of this study is to investigate the interface between the femur rat bone and the new bone that is obtained using a method of tissue engineering that is based on two artificial matrixes inserted in previously artificially induced defects. For this study, under strict supervision 20 rats were used in conformity with ethical procedures. In all the femurs a round defect was induced by drilling with a 1 mm spherical Co-Cr surgical drill. The matrixes used were IngeniOss (for ten samples) and 4Bone(for the other ten samples). These materials were inserted into the induced defects. The femurs were investigated at 1 month, after the surgical procedures. The interfaces were examined using Time Domain (TD) Optical Coherence Tomography (OCT) combined with Confocal Microscopy (CM). The scanning procedure is similar to that used in any CM, where the fast scanning is en-face (line rate) and the scanning in depth is much slower (at the frame rate). The optical configuration uses two single mode directional couplers with a superluminiscent diode as the source centered at 1300 nm. The results showed open interfaces due to the insufficient healing process, as well as closed interfaces due to a new bone formation inside the defect. The conclusion of this study is that TD-OCT can act as a valuable tool in the investigation of the interface between the old bone and the one that has been newly created due to the osteoinductive process. The TD-OCT has proven a valuable tool for the non-invasive evaluation of the matrix bone interfaces.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Yocum, D.R.; Berman, E.; Canal, P.
2007-05-01
As one of the founding members of the Open Science Grid Consortium (OSG), Fermilab enables coherent access to its production resources through the Grid infrastructure system called FermiGrid. This system successfully provides for centrally managed grid services, opportunistic resource access, development of OSG Interfaces for Fermilab, and an interface to the Fermilab dCache system. FermiGrid supports virtual organizations (VOs) including high energy physics experiments (USCMS, MINOS, D0, CDF, ILC), astrophysics experiments (SDSS, Auger, DES), biology experiments (GADU, Nanohub) and educational activities.
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A New Approach in Force-Limited Vibration Testing of Flight Hardware
NASA Technical Reports Server (NTRS)
Kolaini, Ali R.; Kern, Dennis L.
2012-01-01
The force-limited vibration test approaches discussed in NASA-7004C were developed to reduce overtesting associated with base shake vibration tests of aerospace hardware where the interface responses are excited coherently. This handbook outlines several different methods of specifying the force limits. The rationale for force limiting is based on the disparity between the impedances of typical aerospace mounting structures and the large impedances of vibration test shakers when the interfaces in general are coherently excited. Among these approaches, the semi-empirical method is presently the most widely used method to derive the force limits. The inclusion of the incoherent excitation of the aerospace structures at mounting interfaces has not been accounted for in the past and provides the basis for more realistic force limits for qualifying the hardware using shaker testing. In this paper current methods for defining the force limiting specifications discussed in the NASA handbook are reviewed using data from a series of acoustic and vibration tests. A new approach based on considering the incoherent excitation of the structural mounting interfaces using acoustic test data is also discussed. It is believed that the new approach provides much more realistic force limits that may further remove conservatism inherent in shaker vibration testing not accounted for by methods discussed in the NASA handbook. A discussion on using FEM/BEM analysis to obtain realistic force limits for flight hardware is provided.
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NASA Astrophysics Data System (ADS)
Cheaito, Ramez; Polanco, Carlos A.; Addamane, Sadhvikas; Zhang, Jingjie; Ghosh, Avik W.; Balakrishnan, Ganesh; Hopkins, Patrick E.
2018-02-01
We report on the room temperature thermal conductivity of AlAs-GaAs superlattices (SLs), in which we systematically vary the period thickness and total thickness between 2 -24 nm and 20.1 -2 ,160 nm , respectively. The thermal conductivity increases with the SL thickness and plateaus at a thickness around 200 nm, showing a clear transition from a quasiballistic to a diffusive phonon transport regime. These results demonstrate the existence of classical size effects in SLs, even at the highest interface density samples. We use harmonic atomistic Green's function calculations to capture incoherence in phonon transport by averaging the calculated transmission over several purely coherent simulations of independent SL with different random mixing at the AlAs-GaAs interfaces. These simulations demonstrate the significant contribution of incoherent phonon transport through the decrease in the transmission and conductance in the SLs as the number of interfaces increases. In spite of this conductance decrease, our simulations show a quasilinear increase in thermal conductivity with the superlattice thickness. This suggests that the observation of a quasilinear increase in thermal conductivity can have important contributions from incoherent phonon transport. Furthermore, this seemingly linear slope in thermal conductivity versus SL thickness data may actually be nonlinear when extended to a larger number of periods, which is a signature of incoherent effects. Indeed, this trend for superlattices with interatomic mixing at the interfaces could easily be interpreted as linear when the number of periods is small. Our results reveal that the change in thermal conductivity with period thickness is dominated by incoherent (particlelike) phonons, whose properties are not dictated by changes in the AlAs or GaAs phonon dispersion relations. This work demonstrates the importance of studying both period and sample thickness dependencies of thermal conductivity to understand the relative contributions of coherent and incoherent phonon transport in the thermal conductivity in SLs.
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Role of surfaces and interfaces in controlling the mechanical properties of metallic alloys.
Lee, Won-Jong; Chia, Wen-Jui; Wang, Jinliu; Chen, Yanfeng; Vaynman, Semyon; Fine, Morris E; Chung, Yip-Wah
2010-11-02
This article explores the subtle effects of surfaces and interfaces on the mechanical properties of bulk metallic alloys using three examples: environmental effects on fatigue life, hydrogen embrittlement effects on the ductility of intermetallics, and the role of coherent precipitates in the toughness of steels. It is demonstrated that the marked degradation of the fatigue life of metals is due to the strong chemisorption of adsorbates on exposed slip steps that are formed during fatigue deformation. These adsorbates reduce the reversibility of slip, thus accelerating fatigue damage in a chemically active gas environment. For certain intermetallic alloys such as Ni(3)Al and Ni(3)Fe, the ductility depends on the ambient gas composition and the atomic ordering in these alloys, both of which govern the complex surface chemical reactions taking place in the vicinity of crack tips. Finally, it is shown that local stresses at a coherent precipitate-matrix interface can activate dislocation motion at low temperatures, thus improving the fracture toughness of bulk alloys such as steels at cryogenic temperatures. These examples illustrate the complex interplay between surface chemistry and mechanics, often yielding unexpected results.
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Optimization and Control of Burning Plasmas Through High Performance Computing
DOE Office of Scientific and Technical Information (OSTI.GOV)
Pankin, Alexei
This project has revived the FACETS code, that has been developed under SciDAC fund- ing in 2008-2012. The code has been dormant for a number of years after the SciDAC funding stopped. FACETS depends on external packages. The external packages and libraries such as PETSc, FFTW, HDF5 and NETCDF that are included in FACETS have evolved during these years. Some packages in FACETS are also parts of other codes such as PlasmaState, NUBEAM, GACODES, and UEDGE. These packages have been also evolved together with their host codes which include TRANSP, TGYRO and XPTOR. Finally, there is also a set ofmore » packages in FACETS that are being developed and maintained by Tech-X. These packages include BILDER, SciMake, and FcioWrappers. Many of these packages evolved significantly during the last several years and FACETS had to be updated to synchronize with the re- cent progress in the external packages. The PI has introduced new changes to the BILDER package to support the updated interfaces to the external modules. During the last year of the project, the FACETS version of the UEDGE code has been extracted from FACETS as a standalone package. The PI collaborates with the scientists from LLNL on the updated UEDGE model in FACETS. Drs. T. Rognlien, M. Umansky and A. Dimits from LLNL are contributing to this task.« less
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Zhao, Jiagang; Sun, Woong; Cho, Hyo Min; Ouyang, Hong; Li, Wenlin; Lin, Ying; Do, Jiun; Zhang, Liangfang; Ding, Sheng; Liu, Yizhi; Lu, Paul; Zhang, Kang
2013-01-04
Spinal cord injury (SCI) results in devastating motor and sensory deficits secondary to disrupted neuronal circuits and poor regenerative potential. Efforts to promote regeneration through cell extrinsic and intrinsic manipulations have met with limited success. Stem cells represent an as yet unrealized therapy in SCI. Recently, we identified novel culture methods to induce and maintain primitive neural stem cells (pNSCs) from human embryonic stem cells. We tested whether transplanted human pNSCs can integrate into the CNS of the developing chick neural tube and injured adult rat spinal cord. Following injection of pNSCs into the developing chick CNS, pNSCs integrated into the dorsal aspects of the neural tube, forming cell clusters that spontaneously differentiated into neurons. Furthermore, following transplantation of pNSCs into the lesioned rat spinal cord, grafted pNSCs survived, differentiated into neurons, and extended long distance axons through the scar tissue at the graft-host interface and into the host spinal cord to form terminal-like structures near host spinal neurons. Together, these findings suggest that pNSCs derived from human embryonic stem cells differentiate into neuronal cell types with the potential to extend axons that associate with circuits of the CNS and, more importantly, provide new insights into CNS integration and axonal regeneration, offering hope for repair in SCI.
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Neurofeedback training of alpha-band coherence enhances motor performance.
Mottaz, Anais; Solcà, Marco; Magnin, Cécile; Corbet, Tiffany; Schnider, Armin; Guggisberg, Adrian G
2015-09-01
Neurofeedback training of motor cortex activations with brain-computer interface systems can enhance recovery in stroke patients. Here we propose a new approach which trains resting-state functional connectivity associated with motor performance instead of activations related to movements. Ten healthy subjects and one stroke patient trained alpha-band coherence between their hand motor area and the rest of the brain using neurofeedback with source functional connectivity analysis and visual feedback. Seven out of ten healthy subjects were able to increase alpha-band coherence between the hand motor cortex and the rest of the brain in a single session. The patient with chronic stroke learned to enhance alpha-band coherence of his affected primary motor cortex in 7 neurofeedback sessions applied over one month. Coherence increased specifically in the targeted motor cortex and in alpha frequencies. This increase was associated with clinically meaningful and lasting improvement of motor function after stroke. These results provide proof of concept that neurofeedback training of alpha-band coherence is feasible and behaviorally useful. The study presents evidence for a role of alpha-band coherence in motor learning and may lead to new strategies for rehabilitation. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Piot, P.; Sun, Y. -E; Maxwell, T. J.
2011-06-27
We experimentally demonstrate the production of narrow-band (δf/f ~ =20% at f ~ = 0.5 THz) THz transition radiation with tunable frequency over [0.37, 0.86] THz. The radiation is produced as a train of sub-picosecond relativistic electron bunches transits at the vacuum-aluminum interface of an aluminum converter screen. In addition, we show a possible application of modulated beams to extend the dynamical range of a popular bunch length diagnostic technique based on the spectral analysis of coherent radiation.
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Virtual memory support for distributed computing environments using a shared data object model
NASA Astrophysics Data System (ADS)
Huang, F.; Bacon, J.; Mapp, G.
1995-12-01
Conventional storage management systems provide one interface for accessing memory segments and another for accessing secondary storage objects. This hinders application programming and affects overall system performance due to mandatory data copying and user/kernel boundary crossings, which in the microkernel case may involve context switches. Memory-mapping techniques may be used to provide programmers with a unified view of the storage system. This paper extends such techniques to support a shared data object model for distributed computing environments in which good support for coherence and synchronization is essential. The approach is based on a microkernel, typed memory objects, and integrated coherence control. A microkernel architecture is used to support multiple coherence protocols and the addition of new protocols. Memory objects are typed and applications can choose the most suitable protocols for different types of object to avoid protocol mismatch. Low-level coherence control is integrated with high-level concurrency control so that the number of messages required to maintain memory coherence is reduced and system-wide synchronization is realized without severely impacting the system performance. These features together contribute a novel approach to the support for flexible coherence under application control.
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Extraordinary Tools for Extraordinary Science: The Impact ofSciDAC on Accelerator Science&Technology
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ryne, Robert D.
2006-08-10
Particle accelerators are among the most complex and versatile instruments of scientific exploration. They have enabled remarkable scientific discoveries and important technological advances that span all programs within the DOE Office of Science (DOE/SC). The importance of accelerators to the DOE/SC mission is evident from an examination of the DOE document, ''Facilities for the Future of Science: A Twenty-Year Outlook''. Of the 28 facilities listed, 13 involve accelerators. Thanks to SciDAC, a powerful suite of parallel simulation tools has been developed that represent a paradigm shift in computational accelerator science. Simulations that used to take weeks or more now takemore » hours, and simulations that were once thought impossible are now performed routinely. These codes have been applied to many important projects of DOE/SC including existing facilities (the Tevatron complex, the Relativistic Heavy Ion Collider), facilities under construction (the Large Hadron Collider, the Spallation Neutron Source, the Linac Coherent Light Source), and to future facilities (the International Linear Collider, the Rare Isotope Accelerator). The new codes have also been used to explore innovative approaches to charged particle acceleration. These approaches, based on the extremely intense fields that can be present in lasers and plasmas, may one day provide a path to the outermost reaches of the energy frontier. Furthermore, they could lead to compact, high-gradient accelerators that would have huge consequences for US science and technology, industry, and medicine. In this talk I will describe the new accelerator modeling capabilities developed under SciDAC, the essential role of multi-disciplinary collaboration with applied mathematicians, computer scientists, and other IT experts in developing these capabilities, and provide examples of how the codes have been used to support DOE/SC accelerator projects.« less
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NASA Astrophysics Data System (ADS)
Ryne, Robert D.
2006-09-01
Particle accelerators are among the most complex and versatile instruments of scientific exploration. They have enabled remarkable scientific discoveries and important technological advances that span all programs within the DOE Office of Science (DOE/SC). The importance of accelerators to the DOE/SC mission is evident from an examination of the DOE document, ''Facilities for the Future of Science: A Twenty-Year Outlook.'' Of the 28 facilities listed, 13 involve accelerators. Thanks to SciDAC, a powerful suite of parallel simulation tools has been developed that represent a paradigm shift in computational accelerator science. Simulations that used to take weeks or more now take hours, and simulations that were once thought impossible are now performed routinely. These codes have been applied to many important projects of DOE/SC including existing facilities (the Tevatron complex, the Relativistic Heavy Ion Collider), facilities under construction (the Large Hadron Collider, the Spallation Neutron Source, the Linac Coherent Light Source), and to future facilities (the International Linear Collider, the Rare Isotope Accelerator). The new codes have also been used to explore innovative approaches to charged particle acceleration. These approaches, based on the extremely intense fields that can be present in lasers and plasmas, may one day provide a path to the outermost reaches of the energy frontier. Furthermore, they could lead to compact, high-gradient accelerators that would have huge consequences for US science and technology, industry, and medicine. In this talk I will describe the new accelerator modeling capabilities developed under SciDAC, the essential role of multi-disciplinary collaboration with applied mathematicians, computer scientists, and other IT experts in developing these capabilities, and provide examples of how the codes have been used to support DOE/SC accelerator projects.
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Bourlier, Christophe; Kubické, Gildas; Déchamps, Nicolas
2008-04-01
A fast, exact numerical method based on the method of moments (MM) is developed to calculate the scattering from an object below a randomly rough surface. Déchamps et al. [J. Opt. Soc. Am. A23, 359 (2006)] have recently developed the PILE (propagation-inside-layer expansion) method for a stack of two one-dimensional rough interfaces separating homogeneous media. From the inversion of the impedance matrix by block (in which two impedance matrices of each interface and two coupling matrices are involved), this method allows one to calculate separately and exactly the multiple-scattering contributions inside the layer in which the inverses of the impedance matrices of each interface are involved. Our purpose here is to apply this method for an object below a rough surface. In addition, to invert a matrix of large size, the forward-backward spectral acceleration (FB-SA) approach of complexity O(N) (N is the number of unknowns on the interface) proposed by Chou and Johnson [Radio Sci.33, 1277 (1998)] is applied. The new method, PILE combined with FB-SA, is tested on perfectly conducting circular and elliptic cylinders located below a dielectric rough interface obeying a Gaussian process with Gaussian and exponential height autocorrelation functions.
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Beckwith, M. A.; Jiang, S.; Schropp, A.; ...
2017-05-01
Tuning the energy of an x-ray probe to an absorption line or edge can provide material-specific measurements that are particularly useful for interfaces. Simulated hard x-ray images above the Fe K-edge are presented to examine ion diffusion across an interface between Fe 2O 3 and SiO 2 aerogel foam materials. The simulations demonstrate the feasibility of such a technique for measurements of density scale lengths near the interface with submicron spatial resolution. A proof-of-principle experiment is designed and performed at the Linac coherent light source facility. Preliminary data show the change of the interface after shock compression and heating withmore » simultaneous fluorescence spectra for temperature determination. Here, the results provide the first demonstration of using x-ray imaging at an absorption edge as a diagnostic to detect ultrafast phenomena for interface physics in high-energy-density systems.« less
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NASA Astrophysics Data System (ADS)
Barbé, Elric; Fu, Chu-Chun; Sauzay, Maxime
2018-02-01
It is known that microcrack initiation in metallic alloys containing second-phase particles may be caused by either an interfacial or an intraprecipitate fracture. So far, the dependence of these features on properties of the precipitate and the interface is not clearly known. The present study aims to determine the key properties of carbide-metal interfaces controlling the energy and critical stress of fracture, based on density functional theory (DFT) calculations. We address coherent interfaces between a fcc iron or nickel matrix and a frequently observed carbide, the M23C6 , for which a simplified chemical composition Cr23C6 is assumed. The interfacial properties such as the formation and Griffith energies, and the effective Young's modulus are analyzed as functions of the magnetic state of the metal lattice, including the paramagnetic phase of iron. Interestingly, a simpler antiferromagnetic phase is found to exhibit similar interfacial mechanical behavior to the paramagnetic phase. A linear dependence is determined between the surface (and interface) energy and the variation of the number of chemical bonds weighted by the respective bond strength, which can be used to predict the relative formation energy for the surface and interface with various chemical terminations. Finally, the critical stresses of both intraprecipitate and interfacial fractures due to a tensile loading are estimated via the universal binding energy relation (UBER) model, parametrized on the DFT data. The validity of this model is verified in the case of intraprecipitate fracture, against results from DFT tensile test simulations. In agreement with experimental evidences, we predict a much stronger tendency for an interfacial fracture for this carbide. In addition, the calculated interfacial critical stresses are fully compatible with available experimental data in steels, where the interfacial carbide-matrix fracture is only observed at incoherent interfaces.
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Del-Ama, Antonio J; Gil-Agudo, Angel; Pons, José L; Moreno, Juan C
2014-01-01
Locomotor training has proved to provide beneficial effect in terms of mobility in incomplete paraplegic patients. Neuroprosthetic technology can contribute to increase the efficacy of a training paradigm in the promotion of a locomotor pattern. Robotic exoskeletons can be used to manage the unavoidable loss of performance of artificially driven muscles. Hybrid exoskeletons blend complementary robotic and neuro-prosthetic technologies. The aim of this pilot study was to determine the effects of hybrid gait training in three case studies with persons with incomplete spinal cord injury (iSCI) in terms of locomotion performance during assisted gait, patient-robot adaptations, impact on ambulation and assessment of lower limb muscle strength and spasticity. Participants with iSCI received interventions with a hybrid bilateral exoskeleton for 4 days. Assessment of gait function revealed that patients improved the 6 min and 10 m walking tests after the intervention, and further improvements were observed 1 week after the intervention. Muscle examination revealed improvements in knee and hip sagittal muscle balance scores and decreased score in ankle extensor balance. It is concluded that improvements in biomechanical function of the knee joint after the tested overground hybrid gait trainer are coherent with improvements in gait performance.
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del-Ama, Antonio J.; Gil-Agudo, Ángel; Pons, José L.; Moreno, Juan C.
2014-01-01
Locomotor training has proved to provide beneficial effect in terms of mobility in incomplete paraplegic patients. Neuroprosthetic technology can contribute to increase the efficacy of a training paradigm in the promotion of a locomotor pattern. Robotic exoskeletons can be used to manage the unavoidable loss of performance of artificially driven muscles. Hybrid exoskeletons blend complementary robotic and neuro-prosthetic technologies. The aim of this pilot study was to determine the effects of hybrid gait training in three case studies with persons with incomplete spinal cord injury (iSCI) in terms of locomotion performance during assisted gait, patient-robot adaptations, impact on ambulation and assessment of lower limb muscle strength and spasticity. Participants with iSCI received interventions with a hybrid bilateral exoskeleton for 4 days. Assessment of gait function revealed that patients improved the 6 min and 10 m walking tests after the intervention, and further improvements were observed 1 week after the intervention. Muscle examination revealed improvements in knee and hip sagittal muscle balance scores and decreased score in ankle extensor balance. It is concluded that improvements in biomechanical function of the knee joint after the tested overground hybrid gait trainer are coherent with improvements in gait performance. PMID:24860478
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Upper limb functional electrical stimulation devices and their man-machine interfaces.
Venugopalan, L; Taylor, P N; Cobb, J E; Swain, I D
2015-01-01
Functional Electrical Stimulation (FES) is a technique that uses electricity to activate the nerves of a muscle that is paralysed due to hemiplegia, multiple sclerosis, Parkinson's disease or spinal cord injury (SCI). FES has been widely used to restore upper limb functions in people with hemiplegia and C5-C7 tetraplegia and has improved their ability to perform their activities of daily living (ADL). At the time of writing, a detailed literature review of the existing upper limb FES devices and their man-machine interfaces (MMI) showed that only the NESS H200 was commercially available. However, the rigid arm splint doesn't fit everyone and prevents the use of a tenodesis grip. Hence, a robust and versatile upper limb FES device that can be used by a wider group of people is required.
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Lu, Yun; Liu, Hongwei; Gao, Runan; Xiao, Shaoliang; Zhang, Ming; Yin, Yafang; Wang, Siqun; Li, Jian; Yang, Dongjiang
2016-10-26
Nanofibrillated cellulose (NFC) has received increasing attention in science and technology because of not only the availability of large amounts of cellulose in nature but also its unique structural and physical features. These high-aspect-ratio nanofibers have potential applications in water remediation and as a reinforcing scaffold in composites, coatings, and porous materials because of their fascinating properties. In this work, highly porous NFC aerogels were prepared based on tert-butanol freeze-drying of ultrasonically isolated bamboo NFC with 20-80 nm diameters. Then nonagglomerated 2-20-nm-diameter silver oxide (Ag 2 O) nanoparticles (NPs) were grown firmly onto the NFC scaffold with a high loading content of ∼500 wt % to fabricate Ag 2 O@NFC organic-inorganic composite aerogels (Ag 2 O@NFC). For the first time, the coherent interface and interaction mechanism between the cellulose I β nanofiber and Ag 2 O NPs are explored by high-resolution transmission electron microscopy and 3D electron tomography. Specifically, a strong hydrogen between Ag 2 O and NFC makes them grow together firmly along a coherent interface, where good lattice matching between specific crystal planes of Ag 2 O and NFC results in very small interfacial straining. The resulting Ag 2 O@NFC aerogels take full advantage of the properties of the 3D organic aerogel framework and inorganic NPs, such as large surface area, interconnected porous structures, and supreme mechanical properties. They open up a wide horizon for functional practical usage, for example, as a flexible superefficient adsorbent to capture I - ions from contaminated water and trap I 2 vapor for safe disposal, as presented in this work. The viable binding mode between many types of inorganic NPs and organic NFC established here highlights new ways to investigate cellulose-based functional nanocomposites.
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Interface Properties of Wide Bandgap Semiconductor Structures
1994-06-01
resistive than silicides and their chemistry with 126I I Si-based materials more complex. However, in a series of studies, M. 0. Aboelfotoh et al. have...clarification of these issues. CuGe contacts on Ge:GaN and Mg:GaN. To date, the properties of Cu3Ge films have been documented by Aboelfotoh et al., but the...Martin, V. Malhotra, and J. E. Mahan, J. Vac. Sci. Technol. B 3, 836 (1985). 25. L. Krusin-Elbaum and M. 0. Aboelfotoh , Appl. Phys. Lett. 58(12), 1341
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Chemical Bonding, Interdiffusion and Electronic Structure at InP, GaAs, and Si-Metal Interfaces.
1984-01-15
1980) 420. 37. A. Hiraki , K. Shuts. F. Kim. W. Kammura. and W. Iwami, A\\ppl. Phys. Len. 31 (1977) 611, and references therein. 38. L.J. Brilison, C.F...and references therein. 5. A. Hiraki , M.A. Nicolet, and J.W. Mayer, Appi. Phys. Lett. !a, 178 (1971); A. Hiraki , K. Shuto, F. Kim, W. Kammura, and W...IZ, 1005 (1980) and references therein. 7. T. Narusawa, K. Kinoshita, W.M. Gibson, and A. Hiraki , J. Vac. Sci. Technol.. Ia. 872 (1981). 8. J
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Comparison of two free-energy expressions and their implications in surface enrichment
NASA Astrophysics Data System (ADS)
Jerry, Rocco A.; Nauman, E. Bruce
1993-08-01
We compare two free-energy expressions, developed by Cohen and Muthukumar [J. Chem. Phys. 90, 5749 (1989)] and by Jerry and Nauman [J. Colloid Interface Sci. 154, 122 (1992)], in terms of their predictions concerning surface enrichment. We show that a term must be added to the former expression so that it may predict the correct dependence of the surface composition on the bulk. The latter expression does predict the correct dependence. We have also derived the quadratic surface-energy contribution from a finite (nonzero) range interaction model.
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Leverage and Delegation in Developing an Information Model for Geology
NASA Astrophysics Data System (ADS)
Cox, S. J.
2007-12-01
GeoSciML is an information model and XML encoding developed by a group of primarily geologic survey organizations under the auspices of the IUGS CGI. The scope of the core model broadly corresponds with information traditionally portrayed on a geologic map, viz. interpreted geology, some observations, the map legend and accompanying memoir. The development of GeoSciML has followed the methodology specified for an Application Schema defined by OGC and ISO 19100 series standards. This requires agreement within a community concerning their domain model, its formal representation using UML, documentation as a Feature Type Catalogue, with an XML Schema implementation generated from the model by applying a rule-based transformation. The framework and technology supports a modular governance process. Standard datatypes and GI components (geometry, the feature and coverage metamodels, metadata) are imported from the ISO framework. The observation and sampling model (including boreholes) is imported from OGC. The scale used for most scalar literal values (terms, codes, measures) allows for localization where necessary. Wildcards and abstract base- classes provide explicit extensibility points. Link attributes appear in a regular way in the encodings, allowing reference to external resources using URIs. The encoding is compatible with generic GI data-service interfaces (WFS, WMS, SOS). For maximum interoperability within a community, the interfaces may be specialised through domain-specified constraints (e.g. feature-types, scale and vocabulary bindings, query-models). Formalization using UML and XML allows use of standard validation and processing tools. Use of upper-level elements defined for generic GI application reduces the development effort and governance resonsibility, while maximising cross-domain interoperability. On the other hand, enabling specialization to be delegated in a controlled manner is essential to adoption across a range of subdisciplines and jurisdictions. The GeoSciML design team is responsible only for the part of the model that is unique to geology but for which general agreement can be reached within the domain. This paper is presented on behalf of the Interoperability Working Group of the IUGS Commission for Geoscience Information (CGI) - follow web-link for details of the membership.
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Petascale supercomputing to accelerate the design of high-temperature alloys
Shin, Dongwon; Lee, Sangkeun; Shyam, Amit; ...
2017-10-25
Recent progress in high-performance computing and data informatics has opened up numerous opportunities to aid the design of advanced materials. Herein, we demonstrate a computational workflow that includes rapid population of high-fidelity materials datasets via petascale computing and subsequent analyses with modern data science techniques. We use a first-principles approach based on density functional theory to derive the segregation energies of 34 microalloying elements at the coherent and semi-coherent interfaces between the aluminium matrix and the θ'-Al 2Cu precipitate, which requires several hundred supercell calculations. We also perform extensive correlation analyses to identify materials descriptors that affect the segregation behaviourmore » of solutes at the interfaces. Finally, we show an example of leveraging machine learning techniques to predict segregation energies without performing computationally expensive physics-based simulations. As a result, the approach demonstrated in the present work can be applied to any high-temperature alloy system for which key materials data can be obtained using high-performance computing.« less
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NASA Astrophysics Data System (ADS)
Hu, X.; Maiti, R.; Liu, X.; Gerhardt, L. C.; Lee, Z. S.; Byers, R.; Franklin, S. E.; Lewis, R.; Matcher, S. J.; Carré, M. J.
2016-03-01
Bio-mechanical properties of the human skin deformed by external forces at difference skin/material interfaces attract much attention in medical research. For instance, such properties are important design factors when one designs a healthcare device, i.e., the device might be applied directly at skin/device interfaces. In this paper, we investigated the bio-mechanical properties, i.e., surface strain, morphological changes of the skin layers, etc., of the human finger-pad and forearm skin as a function of applied pressure by utilizing two non-invasive techniques, i.e., optical coherence tomography (OCT) and digital image correlation (DIC). Skin deformation results of the human finger-pad and forearm skin were obtained while pressed against a transparent optical glass plate under the action of 0.5-24 N force and stretching naturally from 90° flexion to 180° full extension respectively. The obtained OCT images showed the deformation results beneath the skin surface, however, DIC images gave overall information of strain at the surface.
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Petascale supercomputing to accelerate the design of high-temperature alloys
DOE Office of Scientific and Technical Information (OSTI.GOV)
Shin, Dongwon; Lee, Sangkeun; Shyam, Amit
Recent progress in high-performance computing and data informatics has opened up numerous opportunities to aid the design of advanced materials. Herein, we demonstrate a computational workflow that includes rapid population of high-fidelity materials datasets via petascale computing and subsequent analyses with modern data science techniques. We use a first-principles approach based on density functional theory to derive the segregation energies of 34 microalloying elements at the coherent and semi-coherent interfaces between the aluminium matrix and the θ'-Al 2Cu precipitate, which requires several hundred supercell calculations. We also perform extensive correlation analyses to identify materials descriptors that affect the segregation behaviourmore » of solutes at the interfaces. Finally, we show an example of leveraging machine learning techniques to predict segregation energies without performing computationally expensive physics-based simulations. As a result, the approach demonstrated in the present work can be applied to any high-temperature alloy system for which key materials data can be obtained using high-performance computing.« less
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Nanostructure and giant magnetoresistive properties of granular systems.
Kooi, B J; Vystavel, T; De Hosson, J T
2001-03-01
This article aims to make a connection between the microstructures of various nanostructured alloys and giant magnetoresistive (GMR) properties. The GMR behavior of nanoclusters embedded in a nonmagnetic matrix differs considerably from an alloy with the content of a magnetic phase above the percolation threshold; that is to say, an increase of GMR effect upon going from 300 to 10 K for the former and a decrease of the GMR effect for the latter. The following materials systems were examined with high-resolution transmission electron microscopy and magnetoelectrical resistance measurements: magnetic Co and CoFe nanoclusters in a Au matrix, NiFe clusters in a Cu matrix, and NiFe/Cu spinodal decomposition waves with interconnection of the magnetic phase. After annealing (> or = 300 degrees C), Co particles in Au become semi- or incoherent, whereas under other conditions and in all other systems, the interfaces remain coherent. This state of coherency at the interface between magnetic particles and a nonmagnetic matrix turned out to have a detectable influence on the GMR behavior.
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Optical coherence tomography and confocal microscopy investigations of dental prostheses
NASA Astrophysics Data System (ADS)
Negrutiu, Meda L.; Sinescu, Cosmin; Hughes, Michael; Bradu, Adrian; Rominu, Mihai; Todea, Carmen; Dobre, George; Podoleanu, Adrian
2008-09-01
Dental prostheses are very complex systems, heterogenous in structure, made up from various materials, with different physical properties. An essential question mark is on the physical, chemical and mechanical compatibility between these materials. They have to satisfy high stress requirements as well as esthetic challenges. The masticatory stress may induce fractures of the prostheses, which may be triggered by initial materials defects or by alterations of the technological process. The failures of dental prostheses lead to functional, esthetic and phonetic disturbances which finally render the prosthetic treatment inefficient. The purpose of this study is to evaluate the capability of en-face optical coherence tomography as a possible non-invasive high resolution method in supplying the necessary information on the material defects of dental prostheses and microleakage at prosthetic interfaces. C-scan and B-scan OCT images as well as confocal images are acquired from a large range of samples. Gaps between the dental interfaces and material defects are clearly exposed. We conclude that OCT can successfully be used as a noninvasive analysis method.
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Petascale supercomputing to accelerate the design of high-temperature alloys
NASA Astrophysics Data System (ADS)
Shin, Dongwon; Lee, Sangkeun; Shyam, Amit; Haynes, J. Allen
2017-12-01
Recent progress in high-performance computing and data informatics has opened up numerous opportunities to aid the design of advanced materials. Herein, we demonstrate a computational workflow that includes rapid population of high-fidelity materials datasets via petascale computing and subsequent analyses with modern data science techniques. We use a first-principles approach based on density functional theory to derive the segregation energies of 34 microalloying elements at the coherent and semi-coherent interfaces between the aluminium matrix and the θ‧-Al2Cu precipitate, which requires several hundred supercell calculations. We also perform extensive correlation analyses to identify materials descriptors that affect the segregation behaviour of solutes at the interfaces. Finally, we show an example of leveraging machine learning techniques to predict segregation energies without performing computationally expensive physics-based simulations. The approach demonstrated in the present work can be applied to any high-temperature alloy system for which key materials data can be obtained using high-performance computing.
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Pulse-encoded ultrasound imaging of the vitreous with an annular array.
Silverman, Ronald H; Ketterling, Jeffrey A; Mamou, Jonathan; Lloyd, Harriet O; Filoux, Erwan; Coleman, D Jackson
2012-01-01
The vitreous body is nearly transparent both optically and ultrasonically. Conventional 10- to 12-MHz diagnostic ultrasound can detect vitreous inhomogeneities at high gain settings, but has limited resolution and sensitivity, especially outside the fixed focal zone near the retina. To improve visualization of faint intravitreal fluid/gel interfaces, the authors fabricated a spherically curved 20-MHz five-element annular array ultrasound transducer, implemented a synthetic-focusing algorithm to extend the depth-of-field, and used a pulse-encoding strategy to increase sensitivity. The authors evaluated a human subject with a recent posterior vitreous detachment and compared the annular array with conventional 10-MHz ultrasound and spectral-domain optical coherence tomography. With synthetic focusing and chirp pulse-encoding, the array allowed visualization of the formed and fluid components of the vitreous with improved sensitivity and resolution compared with the conventional B-scan. Although optical coherence tomography allowed assessment of the posterior vitreoretinal interface, the ultrasound array allowed evaluation of the entire vitreous body. Copyright 2012, SLACK Incorporated.
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Fiber optic interferometry for industrial process monitoring and control applications
NASA Astrophysics Data System (ADS)
Marcus, Michael A.
2002-02-01
Over the past few years we have been developing applications for a high-resolution (sub-micron accuracy) fiber optic coupled dual Michelson interferometer-based instrument. It is being utilized in a variety of applications including monitoring liquid layer thickness uniformity on coating hoppers, film base thickness uniformity measurement, digital camera focus assessment, optical cell path length assessment and imager and wafer surface profile mapping. The instrument includes both coherent and non-coherent light sources, custom application dependent optical probes and sample interfaces, a Michelson interferometer, custom electronics, a Pentium-based PC with data acquisition cards and LabWindows CVI or LabView based application specific software. This paper describes the development evolution of this instrument platform and applications highlighting robust instrument design, hardware, software, and user interfaces development. The talk concludes with a discussion of a new high-speed instrument configuration, which can be utilized for high speed surface profiling and as an on-line web thickness gauge.
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Multiple Quantum Phase Transitions in a two-dimensional superconductor
NASA Astrophysics Data System (ADS)
Bergeal, Nicolas; Biscaras, J.; Hurand, S.; Feuillet-Palma, C.; Lesueur, J.; Budhani, R. C.; Rastogi, A.; Caprara, S.; Grilli, M.
2013-03-01
We studied the magnetic field driven Quantum Phase Transition (QPT) in electrostatically gated superconducting LaTiO3/SrTiO3 interfaces. Through finite size scaling analysis, we showed that it belongs to the (2 +1)D XY model universality class. The system can be described as a disordered array of superconducting islands coupled by a two dimensional electron gas (2DEG). Depending on the 2DEG conductance tuned by the gate voltage, the QPT is single (corresponding to the long range phase coherence in the whole array) or double (one related to local phase coherence, the other one to the array). By retrieving the coherence length critical exponent ν, we showed that the QPT can be ``clean'' or ``dirty'' according to the Harris criteria, depending on whether the phase coherence length is smaller or larger than the island size. The overall behaviour is well described by a model of coupled superconducting puddles in the framework of the fermionic scenario of 2D superconducting QPT.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Gao, Xiangyu
The ordering transformation occurring in a model Ni-Cr-W superalloy during prolonged exposure to proper temperature has been investigated systematically. It is demonstrated that nanometer-sized precipitates with a DO{sub 22} structure can precipitate in the Ni-Cr-W alloy by means of simple aging treatment at 650–700 °C. The mechanism of transformation to DO{sub 22} superlattice has been determined to be continuous ordering based on the results of high resolution transmission electron microscopy investigation and variation trend in Vickers microhardness. Different variants of DO{sub 22} phase can coexist in the matrix with no signs of overaging as aging time increases, indicating it hasmore » a high thermal stability. The precipitates of DO{sub 22} superlattice has been found to be of ellipsoidal shape which results in the greatest reduction of strain energy. The interfaces between DO{sub 22} precipitates and matrix have been revealed to be coherent at the atomic scale, resulting in considerable coherency strain attributing to the lattice misfit between DO{sub 22} particle and matrix. Because of the high-density nanometer-sized DO{sub 22} phase, the microhardness of the alloy has been improved remarkably after aging treatment. - Graphical abstract: Different variants of the DO{sub 22} superlattice can coexist in the matrix, and the interface between precipitate and the matrix remain coherence at the atomic scale. The three dimensional form of the DO{sub 22} precipitates constructed from three mutually perpendicular projections is an ellipsoidal stick, and the directions of elongations are along the longest axis of the unit cell for DO{sub 22} phase. - Highlights: •The DO{sub 22} phase precipitated in the Ni-Cr-W alloy has a high thermal stability. •The morphology of DO{sub 22} superlattice has been determined to be ellipsoid. •The interface between DO{sub 22} phase and matrix are fully coherent at the atomic scale. •Different variants of DO{sub 22} phase occur equiprobably. •The alloy strength can be improved dramatically by the nanoscale DO{sub 22} particles.« less
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NASA Astrophysics Data System (ADS)
Sugiyama, S.; Hong, Y.-J.; Kasaragod, D.; Makita, S.; Miura, M.; Ikuno, Y.; Yasuno, Y.
2016-03-01
Quantitative evaluation of optical properties of choroid and sclera are performed by multifunctional optical coherence tomography. Five normal eyes, five glaucoma eyes and one choroidal atrophy eye are examined. The refractive error was found to be correlated with choroidal birefringence, polarization uniformity, and flow in addition to scleral birefringence among normal eyes. The significant differences were observed between the normal and the glaucoma eyes, as for choroidal polarization uniformity, flow and scleral birefringence. An automatic segmentation algorithm of retinal pigment epithelium and chorioscleral interface based on multifunctional signals is also presented.
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Effect of the Gouy phase on the coherent phase control of chemical reactions.
Gordon, Robert J; Barge, Vishal J
2007-11-28
We show how the spatial phase of a focused laser beam may be used as a tool for controlling the branching ratio of a chemical reaction. Guoy discovered [Acad. Sci., Paris, C. R. 110, 1250 (1890)] that when an electromagnetic wave passes through a focus its phase increases by pi. In a coherent control scheme involving the absorption of n photons of frequency omega(m) and m photons of frequency omega(n), the overall phase shift produced by the Gouy phase is (n-m)pi. At any given point in space, this phase shift is identical for all reaction products. Nevertheless, if the yields for different reaction channels have different intensity dependencies, the Gouy phase produces a net phase lag between the products that varies with the axial coordinate of the laser focus. We obtain here analytical and numerical values of this phase as the laser focus is scanned across the diameter of the molecular beam, taking into account the Rayleigh range and astigmatism of the laser beam and saturation of the transition. We also show that the modulation depth of the interference pattern may be increased by optimizing the relative intensities of the two fields.
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Korte, C; Keppner, J; Peters, A; Schichtel, N; Aydin, H; Janek, J
2014-11-28
A phenomenological and analytical model for the influence of strain effects on atomic transport in columnar thin films is presented. A model system consisting of two types of crystalline thin films with coherent interfaces is assumed. Biaxial mechanical strain ε0 is caused by lattice misfit of the two phases. The conjoined films consist of columnar crystallites with a small diameter l. Strain relaxation by local elastic deformation, parallel to the hetero-interface, is possible along the columnar grain boundaries. The spatial extent δ0 of the strained hetero-interface regions can be calculated, assuming an exponential decay of the deformation-forces. The effect of the strain field on the local ionic transport in a thin film is then calculated by using the thermodynamic relation between (isostatic) pressure and free activation enthalpy ΔG(#). An expression describing the total ionic transport relative to bulk transport of a thin film or a multilayer as a function of the layer thickness is obtained as an integral average over strained and unstrained regions. The expression depends only on known material constants such as Young modulus Y, Poisson ratio ν and activation volume ΔV(#), which can be combined as dimensionless parameters. The model is successfully used to describe own experimental data from conductivity and diffusion studies. In the second part of the paper a comprehensive literature overview of experimental studies on (fast) ion transport in thin films and multilayers along solid-solid hetero-interfaces is presented. By comparing and reviewing the data the observed interface effects can be classified into three groups: (i) transport along interfaces between extrinsic ionic conductors (and insulator), (ii) transport along an open surface of an extrinsic ionic conductor and (iii) transport along interfaces between intrinsic ionic conductors. The observed effects in these groups differ by about five orders of magnitude in a very consistent way. The modified interface transport in group (i) is most probably caused by strain effects, misfit dislocations or disordered transition regions.
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Xu, Qi; Hu, Dingyin; Duan, Bingyu; He, Jiping
2015-07-01
Epidural spinal cord stimulation (ESCS) combined with partial weight-bearing therapy (PWBT) has been shown to facilitate recovery of functional walking for individuals after spinal cord injury (SCI). The investigation of neural mechanisms of recovery from SCI under this treatment has been conducted broadly in rodent models, yet a suitable ESCS system is still unavailable. This paper describes a practical, programmable, and fully implantable stimulator for laboratory research on rats to explore fundamental neurophysiological principles for functional recovery after SCI. The ESCS system is composed of a personal digital assistant (PDA), an external controller, an implantable pulse generator (IPG), lead extension, and stimulating electrodes. The stimulation parameters can be programmed and adjusted through a graphical user interface on the PDA. The external controller is placed on the rat back and communicates with the PDA via radio-frequency (RF) telemetry. An RF carrier from the class-E power amplifier in the external controller provides both data and power for the IPG through an inductive link. The IPG is built around a microcontroller unit to generate voltage-regulated pulses delivered to the bipolar electrode for ESCS in rats. The encapsulated IPG measures 22 mm × 23 mm × 7 mm with a mass of ∼ 3.78 g. This fully implantable batteryless stimulator provided a simplified and efficient method to carry out chronic experiments in untethered animals for medical electro-neurological research.
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Impact of trace metals on the water structure at the calcite surface
NASA Astrophysics Data System (ADS)
Wolthers, Mariette; Di Tommaso, Devis; De Leeuw, Nora
2014-05-01
Carbonate minerals play an important role in regulating the chemistry of aquatic environments, including the oceans, aquifers, hydrothermal systems, soils and sediments. Through mineral surface processes such as dissolution, precipitation and sorption, carbonate minerals affect the biogeochemical cycles of not only the constituent elements of carbonates, such as Ca, Mg, Fe and C, but also H, P and trace elements. Surface charging of the calcite mineral-water interface, and its reactivity towards foreign ions can be quantified using a surface structural model that includes, among others, the water structure at the interface (i.e. hydrogen bridging) [1,2] in accordance with the CD-MUSIC formalism [3]. Here we will show the impact of foreign metals such as Mg and Sr on the water structure around different surface sites present in etch pits and on growth terraces at the calcite (10-14) surface. We have performed Molecular Dynamics simulations of metal-doped calcite surfaces, using different interatomic water potentials. Results show that the local environment around the structurally distinct sites differs depending on metal presence, suggesting that metal substitutions in calcite affect its reactivity. The information obtained in this study will help in improving existing macroscopic surface model for the reactivity of calcite [2] and give more general insight in mineral surface reactivity in relation to crystal composition. [1] Wolthers, Charlet, & Van Cappellen (2008). Am. J. Sci., 308, 905-941. [2] Wolthers, Di Tommaso, Du, & de Leeuw (2012). Phys. Chem. Chem. Phys. 14, 15145-15157. [3] Hiemstra and Van Riemsdijk (1996) J. Colloid Interf. Sci. 179, 488-508.
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NASA Astrophysics Data System (ADS)
Nasiri-Avanaki, M. R.; Aber, Ahmed; Hojjatoleslami, S. A.; Sira, Mano; Schofield, John B.; Jones, Carole; Podoleanu, A. Gh.
2012-03-01
Basal cell carcinoma (BCC) is the most common form of skin cancer. To improve the diagnostic accuracy, additional non-invasive methods of making a preliminary diagnosis have been sought. We have implemented an En-Face optical coherence tomography (OCT) for this study in which the dynamic focus was integrated into it. With the dynamic focus scheme, the coherence gate moves synchronously with the peak of confocal gate determined by the confocal interface optics. The transversal resolution is then conserved throughout the depth range and an enhanced signal is returned from all depths. The Basal Cell Carcinoma specimens were obtained from the eyelid a patient. The specimens under went analysis by DF-OCT imaging. We searched for remarkable features that were visualized by OCT and compared these findings with features presented in the histology slices.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Damiani, D.; Dubrovin, M.; Gaponenko, I.
Psana(Photon Science Analysis) is a software package that is used to analyze data produced by the Linac Coherent Light Source X-ray free-electron laser at the SLAC National Accelerator Laboratory. The project began in 2011, is written primarily in C++ with some Python, and provides user interfaces in both C++ and Python. Most users use the Python interface. The same code can be run in real time while data are being taken as well as offline, executing on many nodes/cores using MPI for parallelization. It is publicly available and installable on the RHEL5/6/7 operating systems.
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Acute changes associated with electrode insertion measured with optical coherence microscopy
NASA Astrophysics Data System (ADS)
Hammer, Daniel X.; Lozzi, Andrea; Boretsky, Adam; Agrawal, Anant; Welle, Cristin G.
2016-03-01
Despite advances in functional neural imaging, penetrating microelectrodes provide the most direct interface for the extraction of neural signals from the nervous system and are a critical component of many high degree-of-freedom braincomputer interface devices. Electrode insertion is a traumatic event that elicits a complex neuroinflammatory response. In this investigation we applied optical coherence microscopy (OCM), particularly optical coherence angiography (OCA), to characterize the immediate tissue response during microelectrode insertion. Microelectrodes of varying dimension and footprint (one-, two-, and four-shank) were inserted into mouse motor cortex beneath a window after craniotomy surgery. The microelectrodes were inserted in 3-4 steps at 15-20°, with approximately 250 μm linear insertion distance for each step. Before insertion and between each step, OCM datasets were collected, including for quantitative capillary velocimetry. A cohort of control animals without microelectrode insertion was also imaged over a similar time period (2-3 hours). Mechanical tissue deformation was observed in all the experimental animals. The quantitative angiography results varied across animals, and were not correlated with device dimensions. In some cases, localized flow drop-out was observed in a small region surrounding the electrode, while in other instances a global disruption in flow occurred, perhaps as a result of large vessel compression caused by mechanical pressure. OCM is a tool that can be used in various neurophotonics applications, including quantification of the neuroinflammatory response to penetrating electrode insertion.
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NASA Astrophysics Data System (ADS)
Zakharchenko, V. D.; Kovalenko, I. G.; Pak, O. V.; Ryzhkov, V. Yu.
2018-05-01
The problem of coherence violation in stroboscopic ranging with a high resolution in the range due to mutual phase instability of probing and reference radio signals has been considered. It has been shown that the violation of coherence in stroboscopic ranging systems is equivalent to the action of modulating interface and leads to a decrease in the system sensitivity. Requirements have been formulated for the coherence of reference generators in the stroboscopic processing system. The results of statistical modeling have been presented. It was shown that, in the current state of technology with stability of the frequencies of the reference generators, the achieved coherence is sufficient to probe asteroids with super-resolving signals in the range of up to 70 million kilometers. In this case, the dispersion of the signal in cosmic plasma limits the value of the linear resolution of the asteroid details at this range by the value of 2.7 m. Comparison with the current radar resolution of asteroids has been considered, which, at the end of 2015, were 7.5 m in the range of 7 million kilometers.
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Frequency conversion of structured light.
Steinlechner, Fabian; Hermosa, Nathaniel; Pruneri, Valerio; Torres, Juan P
2016-02-15
Coherent frequency conversion of structured light, i.e. the ability to manipulate the carrier frequency of a wave front without distorting its spatial phase and intensity profile, provides the opportunity for numerous novel applications in photonic technology and fundamental science. In particular, frequency conversion of spatial modes carrying orbital angular momentum can be exploited in sub-wavelength resolution nano-optics and coherent imaging at a wavelength different from that used to illuminate an object. Moreover, coherent frequency conversion will be crucial for interfacing information stored in the high-dimensional spatial structure of single and entangled photons with various constituents of quantum networks. In this work, we demonstrate frequency conversion of structured light from the near infrared (803 nm) to the visible (527 nm). The conversion scheme is based on sum-frequency generation in a periodically poled lithium niobate crystal pumped with a 1540-nm Gaussian beam. We observe frequency-converted fields that exhibit a high degree of similarity with the input field and verify the coherence of the frequency-conversion process via mode projection measurements with a phase mask and a single-mode fiber. Our results demonstrate the suitability of exploiting the technique for applications in quantum information processing and coherent imaging.
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A multi-archive coherent chronology: from Greenland to the Mediterranean sea
NASA Astrophysics Data System (ADS)
Bazin, Lucie; Landais, Amaelle; Lemieux-Dudon, Bénédicte; Siani, Giuseppe; Michel, Elisabeth; Combourieu-Nebout, Nathalie; Blamart, Dominique; Genty, Dominique
2015-04-01
Understanding the climate mechanisms requires a precise knowledge of the sequence of events during major climate changes. In order to provide precise relationships between changes in orbital and/or greenhouse gases concentration forcing, sea level changes and high vs low latitudes temperatures, a common chronological framework for different paleoclimatic archives is required. Coherent chronologies for ice cores have been recently produced using a bayesian dating tool, DATICE (Lemieux-Dudon et al., 2010, Bazin et al., 2013, Veres et al., 2013). Such tool has been recently developed to include marine cores and speleothems in addition to ice cores. This new development should enable one to test the coherency of different chronologies using absolute and stratigraphic links as well as to provide relationship between climatic changes recorded in different archives. We present here a first application of multi-archive coherent dating including paleoclimatic archives from (1) Greenland (NGRIP ice core), (2) Mediterranean sea (marine core MD90-917, 41° N17° E, 1010 m) and (3) speleothems from the South of France and North Tunisia (Chauvet, Villars and La Mine speleothems, Genty et al., 2006). Thanks to the good absolute chronological constraints from annual layer counting in NGRIP, 14C and tephra layers in MD90-917 and U-Th dating in speleothems, we can provide a precise chronological framework for the last 50 ka (ie. thousand years before present). Then, we present different tests on how to combine the records from the different archives and give the most plausible scenario for the sequence of events at different latitudes over the last deglaciation. Bazin, L., Landais, A. ; Lemieu¬-Dudon, B. ; Kele, H. T. M. ; Veres, D. ; Parrenin, F. ; Martinerie, P. ; Ritz, C. ; Capron, E. ; Lipenkov, V. ; Loutre, M.-F. ; Raynaud, D. ; Vinther, B. ; Svensson, A. ; Rasmussen, S. ; Severi, M. ; Blunier, T. ; Leuenberger, M. ; Fischer, H. ; Masson-¬-Delmotte, V. ; Chappellaz, J. & Wolff, E., An optimized multi-proxy, multi-site Antarctic ice and gas orbital chronology (AICC2012): 120-800 ka,Clim. Past 9, 1715-1731, 2013. Genty, D., Blamart, D., Ghaleb B., Plagnes, V., Causse, Ch., Bakalowicz, M., Zouari, K., Chkir, N., Hellstrom, J., Wainer, K., Bourges, F., Timing and dynamics of the last deglaciation from European and North African δ13C stalagmite profiles - comparison with Chinese ans South Hemisphere stalagmites, Quat. Sci. Rev. 25, 2118-2142, 2006. Lemieux-Dudon, B. ; Blayo, E. ; Petit, J.-R. ; Waelbroeck, C. ;Svensson, A. ; Ritz, C. ; Barnola, J.-M. ; Narcisi, B.M. ; Parrenin, F., Consitent dating for Antarctic and Greenland ice cores, Quat. Sci. Rev. 29(1-2), 2010. Veres, D. ; Bazin, L. ; Landais, A. ; Lemieux-Dudon, B. ; Parrenin, F. ; Martinerie, P. ; Toyé Mahamadou Kele, H. ; Capron, E. ; Chappellaz, J. ; Rasmussen, S. ; Severi, M. ; Svensson, A. ; Vinther, B. & Wolff, E., The Antarctic ice core chronology (AICC2012): an optimized multi-parameter and multi-site dating approach for the last 120 thousand years, Clim. Past, 9, 1733-1748, 2013.
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NASA Astrophysics Data System (ADS)
Bebout, G. E.; King, R. L.
2012-12-01
Fluid flow focused in highly deformed zones (shear zones), and the physical juxtaposition of chemically disparate rocks (via mechanical mixing) in such zones, can lead to extensive metasomatism, including volume strain, and result in rocks with hybridized compositions little resembling the compositions of the incorporated rock types [1-5]. In the Catalina Schist (California), lawsonite-albite, lawsonite-blueschist, and amphibolite-facies units contain shear zones at scales of meters to kilometers, each containing "blocks" (with more spherical or more tabular dimensions) co-facial in grade with the "matrix" surrounding these blocks [1-3]. Oxygen isotope data for these "mélange" units, and adjacent more "coherent" expanses, indicate enhanced fluid flow in the more strongly deforming mélange zones while fluid flow in coherent domains was dominantly fracture-controlled and episodic. The amphibolite-facies mélange unit shows evidence for km-scale equilibration of varying mineral assemblages with H2O-rich fluids with uniform O and H isotope compositions consistent with a lower-grade metasedimentary source. This unit is believed to have formed largely by mechanical mixing of mafic and ultramafic compositions, partly because of the scarcity of sedimentary blocks. However, the mélange matrix in this unit preserves a number of sedimentary chemical/isotopic characteristics (e.g., Pb isotope compositions [3]) that could reflect the incorporation of sedimentary rocks, with or without fluid-related fractionation, and possibly fluid-mediated additions. Tectonically mixed zones such as these, if volumetrically significant at the slab-mantle interface, could exert disproportionate control on the compositions of hydrous fluids or silicate melts emanating from subducting slabs and entering the forearc to backarc mantle wedge, including those contributing to arc magmatism [1-5]. Geochemical studies of arc lavas should consider the possibility that the "fluids" contributed from slabs to arc source regions bear chemical/isotopic signatures reflecting their interaction with these hybridized zones produced by mixing of varying proportions of sedimentary, mafic, and ultramafic compositions. Also, the high-variance hydrous mineral assemblages created by these coeval mechanical and metasomatic processes (e.g., nearly monomineralic chlorite, talc, and amphibole schists) could play an important role in the volatiles budgets at subduction zones (i.e., having stabilities to P and T significantly higher than those for mineral assemblages in metabasaltic and metasedimentary rocks containing the same mineral phases [1,4]). Field, petrologic/geochemical, theoretical, and geophysical studies should work toward assessment of the volumetric significance, physical properties, and devolatilization histories of these hybridized compositions. [1] Bebout and Barton (2002) Chem. Geol. 187:79-106 [2] King et al. (2006) Ear. Planet. Sci. Lett. 246:288-304 [3] King et al. (2007) Chem. Geol. 239:305-322 [4] Spandler et al. (2008) Contrib. Mineral. Petrol. 155:181-198 [5] Miller et al. (2009) Lithos 107:53-67
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West, Christopher R; Crawford, Mark A; Poormasjedi-Meibod, Malihe-Sadat; Currie, Katharine D; Fallavollita, Andre; Yuen, Violet; McNeill, John H; Krassioukov, Andrei V
2014-04-15
Spinal cord injury (SCI) causes altered autonomic control and severe physical deconditioning that converge to drive maladaptive cardiac remodelling. We used a clinically relevant experimental model to investigate the cardio-metabolic responses to SCI and to establish whether passive hind-limb cycling elicits a cardio-protective effect. Initially, 21 male Wistar rats were evenly assigned to three groups: uninjured control (CON), T3 complete SCI (SCI) or T3 complete SCI plus passive hind-limb cycling (SCI-EX; 2 × 30 min day(-1), 5 days week(-1) for 4 weeks beginning 6 days post-SCI). On day 32, cardio-metabolic function was assessed using in vivo echocardiography, ex vivo working heart assessments, cardiac histology/molecular biology and blood lipid profiles. Twelve additional rats (n = 6 SCI and n = 6 SCI-EX) underwent in vivo echocardiography and basal haemodynamic assessments pre-SCI and at days 7, 14 and 32 post-SCI to track temporal cardiovascular changes. Compared with CON, SCI exhibited a rapid and sustained reduction in left ventricular dimensions and function that ultimately manifested as reduced contractility, increased myocardial collagen deposition and an up-regulation of transforming growth factor beta-1 (TGFβ1) and mothers against decapentaplegic homolog 3 (Smad3) mRNA. For SCI-EX, the initial reduction in left ventricular dimensions and function at day 7 post-SCI was completely reversed by day 32 post-SCI, and there were no differences in myocardial contractility between SCI-EX and CON. Collagen deposition was similar between SCI-EX and CON. TGFβ1 and Smad3 were down-regulated in SCI-EX. Blood lipid profiles were improved in SCI-EX versus SCI. We provide compelling novel evidence that passive hind-limb cycling prevents cardiac dysfunction and reduces cardiovascular disease risk in experimental SCI.
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Particle scattering by harmonically trapped Bose and Fermi gases
NASA Astrophysics Data System (ADS)
Bhattacharya, Ankita; Das, Samir; Biswas, Shyamal
2018-04-01
We have analytically explored the quantum phenomenon of particle scattering by harmonically trapped Bose and Fermi gases with the short ranged Fermi–Huang {δ }p3 interactions (Fermi 1936 Ric. Sci. 7 13; Huang and Yang 1957 Phys. Rev. 105 767) interactions among the incident particle and the scatterers. We have predicted differential scattering cross-sections and their temperature dependence in this regard. Coherent scattering even by a single boson or fermion in the finite geometry gives rise to new tool of determining energy eigenstate of the scatterer. Our predictions on the differential scattering cross-sections can be tested within the present day experimental setups, specially, for (i) 3D harmonically trapped interacting Bose–Einstein condensate (BEC), (ii) BECs in a double well, and (iii) BECs in an optical lattice.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Eftink, Benjamin P.; Mara, Nathan Allan; Kingstedt, Owen T.
For this research, Split-Hopkinson pressure bar dynamic compression experiments were conducted to determine the defect/interface interaction dependence on interface type, bilayer thickness and interface orientation with respect to the loading direction in the Ag-Cu eutectic system. Specifically, the deformation microstructure in alloys with either a cube-on-cube orientation relationship with {111} Ag||{111} Cu interface habit planes or a twin orientation relationship with {more » $$\\overline{3}13$$} Ag||{$$\\overline{1}12$$} Cu interface habit planes and with bilayer thicknesses of 500 nm, 1.1 µm and 2.2 µm were probed using TEM. The deformation was carried by dislocation slip and in certain conditions, deformation twinning. The twinning response was dependent on loading orientation with respect to the interface plane, bilayer thickness, and interface type. Twinning was only observed when loading at orientations away from the growth direction and decreased in prevalence with decreasing bilayer thickness. Twinning in Cu was dependent on twinning partial dislocations being transmitted from Ag, which only occurred for cube-on-cube interfaces. Lastly, dislocation slip and deformation twin transfer across the interfaces is discussed in terms of the slip transfer conditions developed for grain boundaries in FCC alloys.« less
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Eftink, Benjamin P.; Mara, Nathan Allan; Kingstedt, Owen T.; ...
2017-12-02
For this research, Split-Hopkinson pressure bar dynamic compression experiments were conducted to determine the defect/interface interaction dependence on interface type, bilayer thickness and interface orientation with respect to the loading direction in the Ag-Cu eutectic system. Specifically, the deformation microstructure in alloys with either a cube-on-cube orientation relationship with {111} Ag||{111} Cu interface habit planes or a twin orientation relationship with {more » $$\\overline{3}13$$} Ag||{$$\\overline{1}12$$} Cu interface habit planes and with bilayer thicknesses of 500 nm, 1.1 µm and 2.2 µm were probed using TEM. The deformation was carried by dislocation slip and in certain conditions, deformation twinning. The twinning response was dependent on loading orientation with respect to the interface plane, bilayer thickness, and interface type. Twinning was only observed when loading at orientations away from the growth direction and decreased in prevalence with decreasing bilayer thickness. Twinning in Cu was dependent on twinning partial dislocations being transmitted from Ag, which only occurred for cube-on-cube interfaces. Lastly, dislocation slip and deformation twin transfer across the interfaces is discussed in terms of the slip transfer conditions developed for grain boundaries in FCC alloys.« less
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An optical/digital processor - Hardware and applications
NASA Technical Reports Server (NTRS)
Casasent, D.; Sterling, W. M.
1975-01-01
A real-time two-dimensional hybrid processor consisting of a coherent optical system, an optical/digital interface, and a PDP-11/15 control minicomputer is described. The input electrical-to-optical transducer is an electron-beam addressed potassium dideuterium phosphate (KD2PO4) light valve. The requirements and hardware for the output optical-to-digital interface, which is constructed from modular computer building blocks, are presented. Initial experimental results demonstrating the operation of this hybrid processor in phased-array radar data processing, synthetic-aperture image correlation, and text correlation are included. The applications chosen emphasize the role of the interface in the analysis of data from an optical processor and possible extensions to the digital feedback control of an optical processor.
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Self-assembled metal nano-multilayered film prepared by co-sputtering method
NASA Astrophysics Data System (ADS)
Xie, Tianle; Fu, Licai; Qin, Wen; Zhu, Jiajun; Yang, Wulin; Li, Deyi; Zhou, Lingping
2018-03-01
Nano-multilayered film is usually prepared by the arrangement deposition of different materials. In this paper, a self-assembled nano-multilayered film was deposited by simultaneous sputtering of Cu and W. The Cu/W nano-multilayered film was accumulated by W-rich layer and Cu-rich layer. Smooth interfaces with consecutive composition variation and semi-coherent even coherent relationship were identified, indicating that a spinodal-like structure with a modulation wavelength of about 20 nm formed during co-deposition process. The participation of diffusion barrier element, such as W, is believed the essential to obtain the nano-multilayered structure besides the technological parameters.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Piot, P.; Maxwell, T. J.; Accelerator Physics Center, Fermi National Accelerator Laboratory, Batavia, Illinois 60510
2011-06-27
We experimentally demonstrate the production of narrow-band ({delta}f/f{approx_equal}20% at f{approx_equal}0.5THz) transition radiation with tunable frequency over [0.37, 0.86] THz. The radiation is produced as a train of sub-picosecond relativistic electron bunches transits at the vacuum-aluminum interface of an aluminum converter screen. The bunch train is generated via a transverse-to-longitudinal phase space exchange technique. We also show a possible application of modulated beams to extend the dynamical range of a popular bunch length diagnostic technique based on the spectral analysis of coherent radiation.
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Digital Fresnel reflection holography for high-resolution 3D near-wall flow measurement.
Kumar, S Santosh; Hong, Jiarong
2018-05-14
We propose a novel backscatter holographic imaging system, as a compact and effective tool for 3D near-wall flow diagnostics at high resolutions, utilizing light reflected at the solid-liquid interface as a reference beam. The technique is fully calibrated, and is demonstrated in a densely seeded channel to achieve a spatial resolution of near-wall flows equivalent to or exceeding prior digital inline holographic measurements using local tracer seeding technique. Additionally, we examined the effects of seeding concentration and laser coherence on the measurement resolution and sample volume resolved, demonstrating the potential to manipulate sample domain by tuning the laser coherence profile.
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Hybrid Quantum Systems with Trapped Charged Particles
NASA Astrophysics Data System (ADS)
Kotler, Shlomi; Leibfried, Dietrich; Simmonds, Raymond; Wineland, Dave
We will review a joint effort by the Ion Storage Group and the Advanced Microwave Photonics Group at NIST (Boulder, CO) to design a hybrid system that interfaces charged particles with macroscopic high-Q resonators. We specifically consider coupling trapped charges to superconducting LC resonators, the mechanical modes of Silicon-Nitride membranes, and piezo-electric materials. We aim to achieve the strong coupling regime, where a single quantum of motion of the trapped charge can be coherently exchanged with harmonic motion of the macroscopic entity (electrical and/or mechanical). These kind of devices could potentially take advantage of both macroscopic control techniques and the long quantum coherence of its trapped charged particles.
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Head wave correlations in ambient noise.
Gebbie, John; Siderius, Martin
2016-07-01
Ambient ocean noise is processed with a vertical line array to reveal coherent time-separated arrivals suggesting the presence of head wave multipath propagation. Head waves, which are critically propagating water waves created by seabed waves traveling parallel to the water-sediment interface, can propagate faster than water-only waves. Such eigenrays are much weaker than water-only eigenrays, and are often completely overshadowed by them. Surface-generated noise is different whereby it amplifies the coherence between head waves and critically propagating water-only waves, which is measured by cross-correlating critically steered beams. This phenomenon is demonstrated both experimentally and with a full wave simulation.
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The diagnosis of nasopharyngeal carcinoma by optical coherence tomography (OCT)
NASA Astrophysics Data System (ADS)
Li, J. H.; Du, Y.
2016-06-01
We have attempted to explore the intrinsic differences in the optical properties of the nasopharyngeal carcinoma (NPC) and normal tissue by optical coherence tomography (OCT). OCT imaging of normal tissue provided three layers of epithelium, lamina propria, and the brighter interface of basement membrane; while carcinomas disrupted the layered construction embedded in signal-poor images. The morphologies were consistent with histological findings. Sensitivity and specificity were 90% and 100%, respectively. This pilot study demonstrates that NPC could be diagnosed by visualization, which implies that OCT might be potentially used to differentiate normal from NPC tissue in the early stage as an invasive biopsy.
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Plasma iron levels appraised 15 days after spinal cord injury in a limb movement animal model.
Reis, F M; Esteves, A M; Tufik, S; de Mello, M T
2011-03-01
Experimental, controlled trial. The purpose of this study was to evaluate plasma iron and transferrin levels in a limb movement animal model with spinal cord injury (SCI). Universidade Federal de São Paulo, Departamento de Psicobiologia. In all, 72 male Wistar rats aged 90 days were divided into four groups: (1) acute SCI (1 day, SCI1), (2) 3 days post-SCI (SCI3), (3) 7 days post-SCI (SCI7) and (4) 15 days post-SCI (SCI15). Each of these groups had corresponding control (CTRL) and SHAM groups. Plasma iron and transferrin levels of the different groups were analyzed using a one-way analysis of variance (ANOVA) followed by Tukey's test. We found a significant reduction in iron plasma levels after SCI compared with the CTRL group: SCI1 (CTRL: 175±10.58 μg dl(-1); SCI: 108.28±11.7 μg dl(-1)), SCI3 (CTRL: 195.5±11.00 μg dl(-1); SCI: 127.88±12.63 μg dl(-1)), SCI7 (CTRL: 186±2.97 μg dl(-1); SCI: 89.2±15.39 μg dl(-1)) and SCI15 (CTRL: 163±5.48 μg dl(-1); SCI: 124.44±10.30 μg dl(-1)) (P<0.05; ANOVA). The SHAM1 group demonstrated a reduction in iron plasma after acute SCI (CTRL: 175±10.58 μg dl(-1); SHAM: 114.60±7.81 μg dl(-1)) (P<0.05; ANOVA). Reduced iron metabolism after SCI may be one of the mechanisms involved in the pathogenesis of sleep-related movement disorders.
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Wang, Xiao; Zhang, Yong-Le; Zhang, Ya-Dong; Xue, Feng
2017-01-01
This study aims to explore the role of the SDF-1/CXCR4 axis in mediating BMSCs and SCI recovery. BMSCs were collected and SCI rat models were established. Wistar rats were assigned into the blank control, sham, SCI, SCI + BMSCs, SCI + BMSCs + SDF-1, SCI + BMSCs + AMD3100 (an inhibitor of SDF-1/CXCR4 axis) and SCI + BMSCs + SDF-1 + AMD3100 groups. Hind limb motor function was measured 7, 14, 21 and 28 days after operation. qRT-PCR, western blotting and ELISA was performed to determine the expressions of SDF-1, CXCR4, NGF, BDNF, GFAP and GAP-43, TNF-α, IL-1β, L-6 and IFN-γ. Hind limb motor function scores 7 days after the operation were reduced in the SCI rats of the blank control and sham groups. Hind limb function was found to be better in the SCI + BMSCs and SCI + BMSCs + SDF-1 groups than in the SCI, SCI + BMSCs + AMD3100 and SCI + BMSCs + SDF-1 + AMD3100 groups 14, 21 and 28 days after operation. Furthermore, the SCI group had lower SDF-1, CXCR4, NGF, BDNF and GAP-43 expressions but higher GFAP, TNF-α, IL-1β, IL-6 and IFN-γ than the blank control and sham groups 28 days after operation. While, the SCI + BMSCs, SCI + BMSCs + SDF-1 and SCI + BMSCs + SDF-1 + AMD3100 groups displayed opposite trends to the SCI and SCI + BMSCs + AMD3100 groups. In conclusion, SDF-1/CXCR4 axis promotes recovery after SCI by mediating BMSCs. PMID:28099928
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A Biomimetic-Computational Approach to Optimizing the Quantum Efficiency of Photovoltaics
NASA Astrophysics Data System (ADS)
Perez, Lisa M.; Holzenburg, Andreas
The most advanced low-cost organic photovoltaic cells have a quantum efficiency of 10%. This is in stark contrast to plant/bacterial light-harvesting systems which offer quantum efficiencies close to unity. Of particular interest is the highly effective quantum coherence-enabled energy transfer (Fig. 1). Noting that quantum coherence is promoted by charged residues and local dielectrics, classical atomistic simulations and time-dependent density functional theory (DFT) are used to identify charge/dielectric patterns and electronic coupling at exactly defined energy transfer interfaces. The calculations make use of structural information obtained on photosynthetic protein-pigment complexes while still in the native membrane making it possible to establish a link between supramolecular organization and quantum coherence in terms of what length scales enable fast energy transport and prevent quenching. Calculating energy transfer efficiencies between components based on different proximities will permit the search for patterns that enable defining material properties suitable for advanced photovoltaics.
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Coherent manipulation of a solid-state artificial atom with few photons.
Giesz, V; Somaschi, N; Hornecker, G; Grange, T; Reznychenko, B; De Santis, L; Demory, J; Gomez, C; Sagnes, I; Lemaître, A; Krebs, O; Lanzillotti-Kimura, N D; Lanco, L; Auffeves, A; Senellart, P
2016-06-17
In a quantum network based on atoms and photons, a single atom should control the photon state and, reciprocally, a single photon should allow the coherent manipulation of the atom. Both operations require controlling the atom environment and developing efficient atom-photon interfaces, for instance by coupling the natural or artificial atom to cavities. So far, much attention has been drown on manipulating the light field with atomic transitions, recently at the few-photon limit. Here we report on the reciprocal operation and demonstrate the coherent manipulation of an artificial atom by few photons. We study a quantum dot-cavity system with a record cooperativity of 13. Incident photons interact with the atom with probability 0.95, which radiates back in the cavity mode with probability 0.96. Inversion of the atomic transition is achieved for 3.8 photons on average, showing that our artificial atom performs as if fully isolated from the solid-state environment.
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NASA Astrophysics Data System (ADS)
Zhang, Zhenbo; Pantleon, Wolfgang
2017-07-01
Oxide nanoparticles are quintessential for ensuring the extraordinary properties of oxide dispersion strengthened (ODS) steels. In this study, the crystallographic structure of oxide nanoparticles, and their interface with the ferritic steel matrix in an Al-alloyed ODS steel, i.e. PM2000, were systematically investigated by high-resolution transmission electron microscopy. The majority of oxide nanoparticles were identified to be orthorhombic YAlO3. During hot consolidation and extrusion, they develop a coherent interface and a near cuboid-on-cube orientation relationship with the ferrite matrix in the material. After annealing at 1200 °C for 1 h, however, the orientation relationship between the oxide nanoparticles and the matrix becomes arbitrary, and their interface mostly incoherent. Annealing at 1300 °C leads to considerable coarsening of oxide nanoparticles, and a new orientation relationship of pseudo-cube-on-cube between oxide nanoparticles and ferrite matrix develops. The reason for the developing interfaces and orientation relationships between oxide nanoparticles and ferrite matrix under different conditions is discussed.
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West, Christopher R; Crawford, Mark A; Poormasjedi-Meibod, Malihe-Sadat; Currie, Katharine D; Fallavollita, Andre; Yuen, Violet; McNeill, John H; Krassioukov, Andrei V
2014-01-01
Spinal cord injury (SCI) causes altered autonomic control and severe physical deconditioning that converge to drive maladaptive cardiac remodelling. We used a clinically relevant experimental model to investigate the cardio-metabolic responses to SCI and to establish whether passive hind-limb cycling elicits a cardio-protective effect. Initially, 21 male Wistar rats were evenly assigned to three groups: uninjured control (CON), T3 complete SCI (SCI) or T3 complete SCI plus passive hind-limb cycling (SCI-EX; 2 × 30 min day−1, 5 days week−1 for 4 weeks beginning 6 days post-SCI). On day 32, cardio-metabolic function was assessed using in vivo echocardiography, ex vivo working heart assessments, cardiac histology/molecular biology and blood lipid profiles. Twelve additional rats (n = 6 SCI and n = 6 SCI-EX) underwent in vivo echocardiography and basal haemodynamic assessments pre-SCI and at days 7, 14 and 32 post-SCI to track temporal cardiovascular changes. Compared with CON, SCI exhibited a rapid and sustained reduction in left ventricular dimensions and function that ultimately manifested as reduced contractility, increased myocardial collagen deposition and an up-regulation of transforming growth factor beta-1 (TGFβ1) and mothers against decapentaplegic homolog 3 (Smad3) mRNA. For SCI-EX, the initial reduction in left ventricular dimensions and function at day 7 post-SCI was completely reversed by day 32 post-SCI, and there were no differences in myocardial contractility between SCI-EX and CON. Collagen deposition was similar between SCI-EX and CON. TGFβ1 and Smad3 were down-regulated in SCI-EX. Blood lipid profiles were improved in SCI-EX versus SCI. We provide compelling novel evidence that passive hind-limb cycling prevents cardiac dysfunction and reduces cardiovascular disease risk in experimental SCI. PMID:24535438
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Pum, D; Weinhandl, M; Hödl, C; Sleytr, U B
1993-01-01
S-layer protein isolated from Bacillus coagulans E38-66 could be recrystallized into large-scale coherent monolayers at an air/water interface and on phospholipid films spread on a Langmuir-Blodgett trough. Because of the asymmetry in the physiochemical surface properties of the S-layer protein, the subunits were associated with their more hydrophobic outer face with the air/water interface and oriented with their negatively charged inner face to the zwitterionic head groups of the dipalmitoylphosphatidylcholine and dipalmitoylphosphatidylethanolamine (DPPE) monolayer films. The dynamic crystal growth at both types of interfaces was first initiated at several distant nucleation points. The individual monocrystalline areas grew isotropically in all directions until the front edge of neighboring crystals was met. The recrystallized S-layer protein and the S-layer-DPPE layer could be chemically cross-linked from the subphase with glutaraldehyde. Images PMID:8478338
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In Situ Monitoring of Chemical Reactions at a Solid-Water Interface by Femtosecond Acoustics.
Shen, Chih-Chiang; Weng, Meng-Yu; Sheu, Jinn-Kong; Yao, Yi-Ting; Sun, Chi-Kuang
2017-11-02
Chemical reactions at a solid-liquid interface are of fundamental importance. Interfacial chemical reactions occur not only at the very interface but also in the subsurface area, while existing monitoring techniques either provide limited spatial resolution or are applicable only for the outmost atomic layer. Here, with the aid of the time-domain analysis with femtosecond acoustics, we demonstrate a subatomic-level-resolution technique to longitudinally monitor chemical reactions at solid-water interfaces, capable of in situ monitoring even the subsurface area under atmospheric conditions. Our work was proven by monitoring the already-known anode oxidation process occurring during photoelectrochemical water splitting. Furthermore, whenever the oxide layer thickness equals an integer number of the effective atomic layer thickness, the measured acoustic echo will show higher signal-to-noise ratios with reduced speckle noise, indicating the quantum-like behavior of this coherent-phonon-based technique.
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2000-05-21
High School Chemistry teacher, for my first thorough appreciation and fine immersion in the scientific method. Mrs. Linda Giffin, Eleventh-Grade...Scott Renner, and Len Seligman . 1997. A consumer viewpoint on `mediator languages -- a proposal for a standard`. SIGMOD Record 26, no. 1: 45-46. http
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Automatic segmentation of the choroid in enhanced depth imaging optical coherence tomography images.
Tian, Jing; Marziliano, Pina; Baskaran, Mani; Tun, Tin Aung; Aung, Tin
2013-03-01
Enhanced Depth Imaging (EDI) optical coherence tomography (OCT) provides high-definition cross-sectional images of the choroid in vivo, and hence is used in many clinical studies. However, the quantification of the choroid depends on the manual labelings of two boundaries, Bruch's membrane and the choroidal-scleral interface. This labeling process is tedious and subjective of inter-observer differences, hence, automatic segmentation of the choroid layer is highly desirable. In this paper, we present a fast and accurate algorithm that could segment the choroid automatically. Bruch's membrane is detected by searching the pixel with the biggest gradient value above the retinal pigment epithelium (RPE) and the choroidal-scleral interface is delineated by finding the shortest path of the graph formed by valley pixels using Dijkstra's algorithm. The experiments comparing automatic segmentation results with the manual labelings are conducted on 45 EDI-OCT images and the average of Dice's Coefficient is 90.5%, which shows good consistency of the algorithm with the manual labelings. The processing time for each image is about 1.25 seconds.
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Coherent structures over Super Hydrophobic and Liquid Infused Surfaces
NASA Astrophysics Data System (ADS)
Arenas, Isnardo; Bernardini, Matteo; Leonardi, Stefano
2017-11-01
Numerical Simulations of two superposed fluids in a turbulent channel have been performed. Both walls of the channel are made of longitudinal riblets with a gas fractions of 0.5 and several pitch values p+ = 18 , 36 , 72 , 144 . For Liquid Infused Surfaces, LIS, with a viscosity ratio m =μ1 /μ2 = 0.4 (where the subscripts 1 and 2 indicate the fluid in the cavities and the overlying fluid respectively) two cases have been considered varying the Weber number: We = 0 , implying an interface sustained by the surface tension and We = 1000 with the dynamics of the interface between the two fluids modeled with a Level Set Approach. Results are compared to the case mimicking water over air (Super hydrophobic Surface SHS m = 0.02) and We = 0 . A smooth channel with one fluid only at Reτ = 180 is used as reference and to assess how the LIS and SHS modify coherent structures near the wall. Numerical simulations were performed on XSEDE TACC under Grant CTS070066. This work was supported by ONR MURI Grants N00014-12-01-0875 and N00014-12-01-0962.
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Magnetic exchange bias of more than 1 Tesla in a natural mineral intergrowth.
McEnroe, Suzanne A; Carter-Stiglitz, Brian; Harrison, Richard J; Robinson, Peter; Fabian, Karl; McCammon, Catherine
2007-10-01
Magnetic exchange bias is a phenomenon whereby the hysteresis loop of a 'soft' magnetic phase is shifted by an amount H(E) along the applied field axis owing to its interaction with a 'hard' magnetic phase. Since the discovery of exchange bias fifty years ago, the development of a general theory has been hampered by the uncertain nature of the interfaces between the hard and soft phases, commonly between an antiferromagnetic phase and a ferro- or ferrimagnetic phase. Exchange bias continues to be the subject of investigation because of its technological applications and because it is now possible to manipulate magnetic materials at the nanoscale. Here we present the first documented example of exchange bias of significant magnitude (>1 T) in a natural mineral. We demonstrate that exchange bias in this system is due to the interaction between coherently intergrown magnetic phases formed through a natural process of phase separation during slow cooling over millions of years. Transmission electron microscopy studies show that these intergrowths have a known crystallographic orientation with a known crystallographic structure and that the interfaces are coherent.
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Software architecture of the Magdalena Ridge Observatory Interferometer
NASA Astrophysics Data System (ADS)
Farris, Allen; Klinglesmith, Dan; Seamons, John; Torres, Nicolas; Buscher, David; Young, John
2010-07-01
Merging software from 36 independent work packages into a coherent, unified software system with a lifespan of twenty years is the challenge faced by the Magdalena Ridge Observatory Interferometer (MROI). We solve this problem by using standardized interface software automatically generated from simple highlevel descriptions of these systems, relying only on Linux, GNU, and POSIX without complex software such as CORBA. This approach, based on gigabit Ethernet with a TCP/IP protocol, provides the flexibility to integrate and manage diverse, independent systems using a centralized supervisory system that provides a database manager, data collectors, fault handling, and an operator interface.
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Crossing turbulent boundaries: interfacial flux in environmental flows.
Grant, Stanley B; Marusic, Ivan
2011-09-01
Advances in the visualization and prediction of turbulence are shedding new light on mass transfer in the turbulent boundary layer. These discoveries have important implications for many topics in environmental science and engineering, from the transport of earth-warming CO2 across the sea-air interface, to nutrient processing and sediment erosion in rivers, lakes, and the ocean, to pollutant removal in water and wastewater treatment systems. In this article we outline current understanding of turbulent boundary layer flows, with particular focus on coherent turbulence and its impact on mass transport across the sediment-water interface in marine and freshwater systems.
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Gerstenberg, Friederike X. R.; Imhoff, Roland; Banse, Rainer; Schmitt, Manfred
2014-01-01
Previous research has shown that different configurations of the implicit self-concept of intelligence (iSCI) and the explicit self-concept of intelligence (eSCI) are consistently related to individuals’ performance on different intelligence tests (Dislich etal., 2012). The results indicated that any discrepant configuration between the iSCI and the eSCI impairs performance. In the present study, how correspondence between the iSCI and the eSCI is related to intelligence test performance as well as personality traits of modesty (low eSCI, high iSCI), narcissism (high eSCI, low iSCI), and achievement motivation was investigated. Furthermore, a moderated mediation analysis showed that the relation between the iSCI–eSCI configurations and intelligence test performance was mediated by achievement motivation for modest individuals. PMID:24575063
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Ploumis, A; Kolli, S; Patrick, M; Owens, M; Beris, A; Marino, R J
2011-03-01
Retrospective database review. To compare lengths of stay (LOS), pressure ulcers and readmissions to the acute care hospital of patients admitted to the inpatient rehabilitation facility (IRF) from a model spinal cord injury (SCI) trauma center or from a non-SCI acute hospital. Only sparse data exist comparing the status of patients admitted to IRF from a model SCI trauma center or from a non-SCI acute hospital. Acute care, IRF and total LOS were compared between patients transferred to IRF from the SCI center (n=78) and from non-SCI centers (n=131). The percentages of pressure ulcers on admission to IRF and transfer back to acute care were also compared. Patients admitted to IRF from the SCI trauma center (SCI TC) had significantly shorter (P=0.01) acute care LOS and total LOS compared with patients admitted from non-SCI TCs. By neurological category, acute-care LOS was less for all groups admitted from the SCI center, but statistically significant only for tetraplegia. There was no significant difference in the incidence of readmissions to acute care from IRF. More patients from non-SCI centers (34%) than SCI centers (12%) had pressure ulcers (P<0.001). Acute care in organized SCI TCs before transfer to IRF can significantly lower acute-care LOS or total LOS and incidence of pressure ulcers compared with non-SCI TCs. Patients admitted to IRF from SCI TCs are no more likely to be sent back to an acute hospital than those from non-SCI TCs.
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Kurup, Sudhi P; Khan, Samira; Gill, Manjot K
2014-11-01
To describe spectral domain optical coherence tomography (SD-OCT) findings of infectious retinitis, including affected layer of retinal involvement, changes at the vitreoretinal interface, and response to therapy. Observational case series. A retrospective review of five patients with infectious retinitis: one with toxoplasmosis, three with herpetic retinitis secondary to cytomegalovirus, and one with herpetic retinitis secondary to varicella zoster virus. Each patient underwent a complete ophthalmologic examination, fundus photography, and SD-OCT imaging (Heidelberg Spectralis; Heidelberg Engineering, Heidelberg, Germany) of the affected retina at the initial visit with serial fundus photography and SD-OCT imaging at follow-up visits. Approval was obtained from the Institutional Review Board of Northwestern University. Spectral domain ocular coherence tomography of retinitis associated with Toxoplasma, cytomegalovirus, or varicella zoster virus demonstrates full-thickness disruption of the retinal architecture and overall thickening. This was in contrast to clinically imitating lesions such as cotton-wool spots, which only showed focal swelling of the inner retina. There was a clear demarcation between the area of active retinitis and unaffected retina. Inactivity was apparent when the previously affected thickened area became atrophic. The SD-OCT also demonstrated changes at the vitreoretinal interface where there was frequently a detachment of the posterior hyaloid (four of five cases) associated with overlying vitreous debris and formation of tractional changes. In the case of varicella zoster virus retinitis, this traction subsequently led to a total retinal detachment. In the assessment of infectious retinitides, SD-OCT is a helpful adjunct to clinical examination and fundus photography. It provides high-resolution detail regarding the border of infectious activity, the vitreoretinal interface, and the differentiation of lesions that can clinically mimic active retinitis. Serial SD-OCT also provides further insight into response to therapy and postinfectious retinal changes by highlighting areas that are at greater risk for complications such as retinal detachment.
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TRMM Precipitation Application Examples Using Data Services at NASA GES DISC
NASA Technical Reports Server (NTRS)
Liu, Zhong; Ostrenga, D.; Teng, W.; Kempler, S.; Greene, M.
2012-01-01
Data services to support precipitation applications are important for maximizing the NASA TRMM (Tropical Rainfall Measuring Mission) and the future GPM (Global Precipitation Mission) mission's societal benefits. TRMM Application examples using data services at the NASA GES DISC, including samples from users around the world will be presented in this poster. Precipitation applications often require near-real-time support. The GES DISC provides such support through: 1) Providing near-real-time precipitation products through TOVAS; 2) Maps of current conditions for monitoring precipitation and its anomaly around the world; 3) A user friendly tool (TOVAS) to analyze and visualize near-real-time and historical precipitation products; and 4) The GES DISC Hurricane Portal that provides near-real-time monitoring services for the Atlantic basin. Since the launch of TRMM, the GES DISC has developed data services to support precipitation applications around the world. In addition to the near-real-time services, other services include: 1) User friendly TRMM Online Visualization and Analysis System (TOVAS; URL: http://disc2.nascom.nasa.gov/Giovanni/tovas/); 2) Mirador (http://mirador.gsfc.nasa.gov/), a simplified interface for searching, browsing, and ordering Earth science data at GES DISC. Mirador is designed to be fast and easy to learn; 3) Data via OPeNDAP (http://disc.sci.gsfc.nasa.gov/services/opendap/). The OPeNDAP provides remote access to individual variables within datasets in a form usable by many tools, such as IDV, McIDAS-V, Panoply, Ferret and GrADS; and 4) The Open Geospatial Consortium (OGC) Web Map Service (WMS) (http://disc.sci.gsfc.nasa.gov/services/wxs_ogc.shtml). The WMS is an interface that allows the use of data and enables clients to build customized maps with data coming from a different network.
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Murray, Amber N; Palhano, Fernando L; Bieschke, Jan; Kelly, Jeffery W
2013-01-01
The accumulation of cross-β-sheet amyloid fibrils is the hallmark of amyloid diseases. Recently, we reported the discovery of amyloid disaggregase activities in extracts from mammalian cells and Caenorhabditis elegans. However, we have discovered a problem with the interpretation of our previous results as Aβ disaggregation in vitro. Here, we show that Aβ fibrils adsorb to the plastic surface of multiwell plates and Eppendorf tubes. This adsorption is markedly increased in the presence of complex biological mixtures subjected to a denaturing air-water interface. The time-dependent loss of thioflavin T fluorescence that we interpreted previously as disaggregation is due to increased adsorption of Aβ amyloid to the surfaces of multiwell plates and Eppendorf tubes in the presence of biological extracts. As the proteins in biological extracts denature over time at the air-water interface due to agitation/shaking, their adsorption increases, in turn promoting adsorption of amyloid fibrils. We delineate important control experiments that quantify the extent of amyloid adsorption to the surface of plastic and quartz containers. Based on the results described in this article, we conclude that our interpretation of the kinetic fibril disaggregation assay data previously reported in Bieschke et al., Protein Sci 2009;18:2231–2241 and Murray et al., Protein Sci 2010;19:836–846 is invalid when used as evidence for a disaggregase activity. Thus, we correct the two prior publications reporting that worm or mammalian cell extracts disaggregate Aβ amyloid fibrils in vitro at 37°C (see Corrigenda in this issue of Protein Science). We apologize for misinterpreting our previous data and for any confounding experimental efforts this may have caused. PMID:23963844
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Murray, Amber N; Palhano, Fernando L; Bieschke, Jan; Kelly, Jeffery W
2013-11-01
The accumulation of cross-β-sheet amyloid fibrils is the hallmark of amyloid diseases. Recently, we reported the discovery of amyloid disaggregase activities in extracts from mammalian cells and Caenorhabditis elegans. However, we have discovered a problem with the interpretation of our previous results as Aβ disaggregation in vitro. Here, we show that Aβ fibrils adsorb to the plastic surface of multiwell plates and Eppendorf tubes. This adsorption is markedly increased in the presence of complex biological mixtures subjected to a denaturing air-water interface. The time-dependent loss of thioflavin T fluorescence that we interpreted previously as disaggregation is due to increased adsorption of Aβ amyloid to the surfaces of multiwell plates and Eppendorf tubes in the presence of biological extracts. As the proteins in biological extracts denature over time at the air-water interface due to agitation/shaking, their adsorption increases, in turn promoting adsorption of amyloid fibrils. We delineate important control experiments that quantify the extent of amyloid adsorption to the surface of plastic and quartz containers. Based on the results described in this article, we conclude that our interpretation of the kinetic fibril disaggregation assay data previously reported in Bieschke et al., Protein Sci 2009;18:2231-2241 and Murray et al., Protein Sci 2010;19:836-846 is invalid when used as evidence for a disaggregase activity. Thus, we correct the two prior publications reporting that worm or mammalian cell extracts disaggregate Aβ amyloid fibrils in vitro at 37°C (see Corrigenda in this issue of Protein Science). We apologize for misinterpreting our previous data and for any confounding experimental efforts this may have caused. © 2013 The Protein Society.
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NASA Astrophysics Data System (ADS)
Matthews, G. Peter
2010-05-01
This presentation will concern the understanding of soil water repellancy and wettability at a fundamental level, and the difficulties of relating the very small, micron scale at which the repellancy and wettability characteristics are produced to the much larger, field scale at which they are normally observed. The presentation will not be a review of past work, but rather will concentrate on recent publications, publications in press, and speculative considerations which may lead to future work in this area. There are three fundamental components of water repellancy - the nature of the soil surfaces themselves, the effect of organic matter and microbiologically produced substances, and the topology of the resultant surfaces. The effects of hydrophobic surfaces will be illustrated by a consideration of the wettability of substances such as commercially produced talc grades. The faces of these platey mineral particles are hydrophobic, whereas their edges are hydrophilic, and the combination not only causes water repellency in itself, but also causes unusual adsorption effects from aqueous solution. The effect of organic matter on soil wettability has been widely studied, often by core-scale wettability experiments. It will be shown how a consideration of micro-wetting effects has led to a more robust data analysis method for such studies (Matthews, G. P. et al, European J.Soil Sci., 2008). Traditionally wetting fronts are assumed to advance in proportion to the square root of time (as predicted by the Washburn equation), but micro-modelling shows that, once inertial effects are taken into account, low-volume fingers of wetting fluid track through porous substances in advance of the observed Washburn wetting front (Bodurtha, P. et al, J.Colloid Interface Sci., 2005). The effects of micro-topology are also well known (Ridgway, C. J. et al, J.Colloid Interface Sci., 2001), but need to be integrated and upscaled, as described below. Soil water repellency is not only dependant on the soil mineral characteristics, surface topology and organic matter content, but is also influenced by microbiological activity. The production of hydrophobic microbial biomass and exudates alter the hydrological characteristics of soil (Chan, K. Y., Soil Sci.Soc.Am.J., 1992) and strengthen the bonds between soil particles. Amongst these are extracellular polymeric substances (EPS), which are produced as a result of microbial activity and increase during periods of substrate utilisation and microbial growth (Hallett, P. D. et al, European J.Soil Sci., 1999). They form part of a wide spectrum of soil organic species, many produced by the soil's bacterial and fungal biomass. EPS provides a living protective membrane between changing hydrological conditions and the micro-organisms. It comprises polysaccharides and smaller amounts of protein, lipids and humic substances, with masses ranging from 103 to 108 kDaltons (Allison, D. G. et al, Fems Microbiology Letters, 1998). The small amounts of EPS in soil have a disproportionately large effect on soil hydraulic properties, and the response of EPS to major perturbations, such as wetting and drying cycles, has recently been well characterised (Or, D. et al, Vadose Zone J, 2007). Therefore, as will be described, the use of EPS as an analogue to the wider range of organic species can lead to an understanding of climatic effects on soil wettability. The upscaling of the effects from micron to field scale requires a highly detailed modelling approach, using a dual -porous void structure model (a modification of the previous ‘Pore-Cor' model) which takes into account both the soil micro-matrix and the macroscopic percolation and wetting pathways (Laudone, G. M. et al, European J.Soil Sci., submitted). Super-hydrophobicity in natural materials (the ‘lotus' effect) and man-made materials (micro-structured arrays) will also be explained and illustrated, and the condition under which super-hydrophobicity can flip to super-wettability. Super-hydrophobicity gives an unusual insight into the less extreme examples of water repellancy found in many soils.
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The Implementation Challenge and the Learning Health System for SCI Initiative.
Stucki, Gerold; Bickenbach, Jerome
2017-02-01
The paper introduces the special issue by linking the International Spinal Cord Injury (InSCI) Community Survey study to the Learning Health System for SCI Initiative (LHS-SCI). The LHS-SCI was designed to respond to the implementation challenge of bringing about policy reform in light of the targeted policy recommendations of World Health Organization's International Perspectives on SCI report as well as the call for action of WHO's Global Disability Action Plan. The paper reviews the components of LHS-SCI relevant to internationally comparable information, a theory of change to guide for action, and the tools for evidence-informed policy. The interplay between persons, their health needs, and the societal response to those needs provides the foundation for the organization of the LHS-SCI Initiative. Moreover, as the other articles in this special issue describe in detail, the rationale, conceptualization, and study design of the InSCI study are also informed by the rationale, and mission, of the LHS for SCI Initiative. The LHS-SCI, and the implementation challenge that motivates it, is responsible for the design of the InSCI study and the overall mission of LHS-SCI to continuously improve the lived experience of people living with SCI around the world through an international evidence- and rights-informed research and policy reform effort.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Pakharukova, V.P., E-mail: verapakh@catalysis.ru; Novosibirsk State University, Pirogova Street 2, 630090 Novosibirsk; Research and Educational Center for Energy Efficient Catalysis, Novosibirsk State University, Novosibirsk 630090
2017-02-15
The structure and nanostructure features of nanocrystalline γ-Al{sub 2}O{sub 3} obtained by dehydration of boehmite with anisotropic platelet-shaped particles were investigated. The original models of 3D coherent nanostructure of γ-Al{sub 2}O{sub 3} were constructed. The models of nanostructured γ-Al{sub 2}O{sub 3} particles were first confirmed by a direct simulation of powder X–Ray diffraction (XRD) patterns using the Debye Scattering Equation (DSE) with assistance of high-resolution transmission electron microscopy (HRTEM) study. The average crystal structure of γ-Al{sub 2}O{sub 3} was shown to be tetragonally distorted. The experimental results revealed that thin γ-Al{sub 2}O{sub 3} platelets were heterogeneous on a nanometer scalemore » and nanometer-sized building blocks were separated by partially coherent interfaces. The XRD simulation results showed that a specific packing of the primary crystalline blocks in the nanostructured γ-Al{sub 2}O{sub 3} particles with formation of planar defects on (001), (100), and (101) planes nicely accounted for pronounced diffuse scattering, anisotropic peak broadening and peak shifts in the experimental XRD pattern. The identified planar defects in cation sublattice seem to be described as filling cation non-spinel sites in existing crystallographic models of γ-Al{sub 2}O{sub 3} structure. The overall findings provided an insight into the complex nanostructure, which is intrinsic to the metastable γ-Al{sub 2}O{sub 3} oxide. - Highlights: • Thin plate-like crystallites of γ-Al{sub 2}O{sub 3} were obtained. • Models of 3D coherent nanostructure of γ-Al{sub 2}O{sub 3} were constructed. • Models were verified by simulating XRD patterns using the Debye Scattering Equation. • Specific broadening of XRD peaks was explained in terms of planar defects. • Primary crystalline blocks in γ-Al{sub 2}O{sub 3} are separated by partially coherent interfaces.« less
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Analytical model of radiation-induced precipitation at the surface of dilute binary alloy
NASA Astrophysics Data System (ADS)
Pechenkin, V. A.; Stepanov, I. A.; Konobeev, Yu. V.
2002-12-01
Growth of precipitate layer at the foil surface of an undersaturated binary alloy under uniform irradiation is treated analytically. Analytical expressions for the layer growth rate, layer thickness limit and final component concentrations in the matrix are derived for coherent and incoherent precipitate-matrix interfaces. It is shown that the high temperature limit of radiation-induced precipitation is the same for both types of interfaces, whereas layer thickness limits are different. A parabolic law of the layer growth predicted for both types of interfaces is in agreement with experimental data on γ '-phase precipitation at the surface of Ni-Si dilute alloys under ion irradiation. Effect of sputtering on the precipitation rate and on the low temperature limit of precipitation under ion irradiation is discussed.
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ITOS to EDGE "Bridge" Software for Morpheus Lunar/Martian Vehicle
NASA Technical Reports Server (NTRS)
Hirsh, Robert; Fuchs, Jordan
2012-01-01
My project Involved Improving upon existing software and writing new software for the Project Morpheus Team. Specifically, I created and updated Integrated Test and Operations Systems (ITOS) user Interfaces for on-board Interaction with the vehicle during archive playback as well as live streaming data. These Interfaces are an integral part of the testing and operations for the Morpheus vehicle providing any and all information from the vehicle to evaluate instruments and insure coherence and control of the vehicle during Morpheus missions. I also created a "bridge" program for Interfacing "live" telemetry data with the Engineering DOUG Graphics Engine (EDGE) software for a graphical (standalone or VR dome) view of live Morpheus nights or archive replays, providing graphical representation of vehicle night and movement during subsequent tests and in real missions.
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NASA Astrophysics Data System (ADS)
Ulbricht, Damian; Elger, Kirsten; Bertelmann, Roland; Klump, Jens
2016-04-01
With the foundation of DataCite in 2009 and the technical infrastructure installed in the last six years it has become very easy to create citable dataset DOIs. Nowadays, dataset DOIs are increasingly accepted and required by journals in reference lists of manuscripts. In addition, DataCite provides usage statistics [1] of assigned DOIs and offers a public search API to make research data count. By linking related information to the data, they become more useful for future generations of scientists. For this purpose, several identifier systems, as ISBN for books, ISSN for journals, DOI for articles or related data, Orcid for authors, and IGSN for physical samples can be attached to DOIs using the DataCite metadata schema [2]. While these are good preconditions to publish data, free and open solutions that help with the curation of data, the publication of research data, and the assignment of DOIs in one software seem to be rare. At GFZ Potsdam we built a modular software stack that is made of several free and open software solutions and we established 'GFZ Data Services'. 'GFZ Data Services' provides storage, a metadata editor for publication and a facility to moderate minted DOIs. All software solutions are connected through web APIs, which makes it possible to reuse and integrate established software. Core component of 'GFZ Data Services' is an eSciDoc [3] middleware that is used as central storage, and has been designed along the OAIS reference model for digital preservation. Thus, data are stored in self-contained packages that are made of binary file-based data and XML-based metadata. The eSciDoc infrastructure provides access control to data and it is able to handle half-open datasets, which is useful in embargo situations when a subset of the research data are released after an adequate period. The data exchange platform panMetaDocs [4] makes use of eSciDoc's REST API to upload file-based data into eSciDoc and uses a metadata editor [5] to annotate the files with metadata. The metadata editor has a user-friendly interface with nominal lists, extensive explanations, and an interactive mapping tool to provide assistance to scientists describing the data. It is possible to deposit metadata templates to fill certain fields with default values. The metadata editor generates metadata in the schemas ISO19139, NASA GCMD DIF, and DataCite and could be extended for other schemas. panMetaDocs is able to mint dataset DOIs through DOIDB, which is our component to moderate dataset DOIs issued through 'GFZ Data Services'. DOIDB accepts metadata in the schemas ISO19139, DIF, and DataCite. In addition, DOIDB provides an OAI-PMH interface to disseminate all deposited metadata to data portals. The presentation of datasets on DOI landing pages is done though XSLT stylesheet transformation of the XML-based metadata. The landing pages have been designed to meet needs of scientists. We are able to render the metadata to different layouts. Furthermore, additional information about datasets and publications is assembled into the webpage by querying public databases on the internet. The work presented here will focus on technical details of the software stack. [1] http://stats.datacite.org [2] http://www.dlib.org/dlib/january11/starr/01starr.html [3] http://www.escidoc.org [4] http://panmetadocs.sf.net [5] http://github.com/ulbricht
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Centrifugally Driven Rayleigh-Taylor Instability
NASA Astrophysics Data System (ADS)
Scase, Matthew; Hill, Richard
2017-11-01
The instability that develops at the interface between two fluids of differing density due to the rapid rotation of the system may be considered as a limit of high-rotation rate Rayleigh-Taylor instability. Previously the authors have considered the effect of rotation on a gravitationally dominated Rayleigh-Taylor instability and have shown that some growth modes of instability may be suppressed completely by the stabilizing effect of rotation (Phys. Rev. Fluids 2:024801, Sci. Rep. 5:11706). Here we consider the case of very high rotation rates and a negligible gravitational field. The initial condition is of a dense inner cylinder of fluid surrounded by a lighter layer of fluid. As the system is rotated about the generating axis of the cylinder, the dense inner fluid moves away from the axis and the familiar bubbles and spikes of Rayleigh-Taylor instability develop at the interface. The system may be thought of as a ``fluid-fluid centrifuge''. By developing a model based on an Orr-Sommerfeld equation, we consider the effects of viscosity, surface tension and interface diffusion on the growth rate and modes of instability. We show that under particular circumstances some modes may be stabilized. School of Mathematical Sciences.
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Silva, Helbert Eustáquio Cardoso da; Gottems, Leila Bernarda Donato
2017-08-01
Secondary care in dentistry in Brazil has scarce and broadly underutilized resources. The challenge is to organize the interface between primary health care (PHC) and secondary care in order to consolidate the population's access to specialist dental care in the Unified Health System (SUS). This article seeks to analyze national publications in Portuguese and English on the interface between secondary health care and primary health care in dentistry from the perspective of comprehensive care in the SUS. It is an integrative review, considering the publications of the following databases: SciELO (Scientific Electronic Library Online), LILACS (Latin American and Caribbean Literature) WEB OF SCIENCE, SCOPUS, PubMed (International Literature on Health Sciences) and GOOGLE SCHOLAR. The search located 966 articles, of which 12 were used in full. Coverage of the oral health teams (ESB) in the family health strategy (ESF), primary health care implementation in a structured way, access to secondary health care, counter-referral to PHC, development of indicators and socioeconomic conditions and inequalities in the distribution of dental specialist centers (CEO) are factors that influence the integrity of oral health care in the SUS.
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Publishing datasets with eSciDoc and panMetaDocs
NASA Astrophysics Data System (ADS)
Ulbricht, D.; Klump, J.; Bertelmann, R.
2012-04-01
Currently serveral research institutions worldwide undertake considerable efforts to have their scientific datasets published and to syndicate them to data portals as extensively described objects identified by a persistent identifier. This is done to foster the reuse of data, to make scientific work more transparent, and to create a citable entity that can be referenced unambigously in written publications. GFZ Potsdam established a publishing workflow for file based research datasets. Key software components are an eSciDoc infrastructure [1] and multiple instances of the data curation tool panMetaDocs [2]. The eSciDoc repository holds data objects and their associated metadata in container objects, called eSciDoc items. A key metadata element in this context is the publication status of the referenced data set. PanMetaDocs, which is based on PanMetaWorks [3], is a PHP based web application that allows to describe data with any XML-based metadata schema. The metadata fields can be filled with static or dynamic content to reduce the number of fields that require manual entries to a minimum and make use of contextual information in a project setting. Access rights can be applied to set visibility of datasets to other project members and allow collaboration on and notifying about datasets (RSS) and interaction with the internal messaging system, that was inherited from panMetaWorks. When a dataset is to be published, panMetaDocs allows to change the publication status of the eSciDoc item from status "private" to "submitted" and prepare the dataset for verification by an external reviewer. After quality checks, the item publication status can be changed to "published". This makes the data and metadata available through the internet worldwide. PanMetaDocs is developed as an eSciDoc application. It is an easy to use graphical user interface to eSciDoc items, their data and metadata. It is also an application supporting a DOI publication agent during the process of publishing scientific datasets as electronic data supplements to research papers. Publication of research manuscripts has an already well established workflow that shares junctures with other processes and involves several parties in the process of dataset publication. Activities of the author, the reviewer, the print publisher and the data publisher have to be coordinated into a common data publication workflow. The case of data publication at GFZ Potsdam displays some specifics, e.g. the DOIDB webservice. The DOIDB is a proxy service at GFZ for the DataCite [4] DOI registration and its metadata store. DOIDB provides a local summary of the dataset DOIs registered through GFZ as a publication agent. An additional use case for the DOIDB is its function to enrich the datacite metadata with additional custom attributes, like a geographic reference in a DIF record. These attributes are at the moment not available in the datacite metadata schema but would be valuable elements for the compilation of data catalogues in the earth sciences and for dissemination of catalogue data via OAI-PMH. [1] http://www.escidoc.org , eSciDoc, FIZ Karlruhe, Germany [2] http://panmetadocs.sf.net , panMetaDocs, GFZ Potsdam, Germany [3] http://metaworks.pangaea.de , panMetaWorks, Dr. R. Huber, MARUM, Univ. Bremen, Germany [4] http://www.datacite.org
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Livny, Miron; Shank, James; Ernst, Michael
Under this SciDAC-2 grant the project’s goal w a s t o stimulate new discoveries by providing scientists with effective and dependable access to an unprecedented national distributed computational facility: the Open Science Grid (OSG). We proposed to achieve this through the work of the Open Science Grid Consortium: a unique hands-on multi-disciplinary collaboration of scientists, software developers and providers of computing resources. Together the stakeholders in this consortium sustain and use a shared distributed computing environment that transforms simulation and experimental science in the US. The OSG consortium is an open collaboration that actively engages new research communities. Wemore » operate an open facility that brings together a broad spectrum of compute, storage, and networking resources and interfaces to other cyberinfrastructures, including the US XSEDE (previously TeraGrid), the European Grids for ESciencE (EGEE), as well as campus and regional grids. We leverage middleware provided by computer science groups, facility IT support organizations, and computing programs of application communities for the benefit of consortium members and the US national CI.« less
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Real-time strap pressure sensor system for powered exoskeletons.
Tamez-Duque, Jesús; Cobian-Ugalde, Rebeca; Kilicarslan, Atilla; Venkatakrishnan, Anusha; Soto, Rogelio; Contreras-Vidal, Jose Luis
2015-02-16
Assistive and rehabilitative powered exoskeletons for spinal cord injury (SCI) and stroke subjects have recently reached the clinic. Proper tension and joint alignment are critical to ensuring safety. Challenges still exist in adjustment and fitting, with most current systems depending on personnel experience for appropriate individual fastening. Paraplegia and tetraplegia patients using these devices have impaired sensation and cannot signal if straps are uncomfortable or painful. Excessive pressure and blood-flow restriction can lead to skin ulcers, necrotic tissue and infections. Tension must be just enough to prevent slipping and maintain posture. Research in pressure dynamics is extensive for wheelchairs and mattresses, but little research has been done on exoskeleton straps. We present a system to monitor pressure exerted by physical human-machine interfaces and provide data about levels of skin/body pressure in fastening straps. The system consists of sensing arrays, signal processing hardware with wireless transmission, and an interactive GUI. For validation, a lower-body powered exoskeleton carrying the full weight of users was used. Experimental trials were conducted with one SCI and one able-bodied subject. The system can help prevent skin injuries related to excessive pressure in mobility-impaired patients using powered exoskeletons, supporting functionality, independence and better overall quality of life.
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Twin-mediated epitaxial growth of highly lattice-mismatched Cu/Ag core-shell nanowires.
Weng, Wei-Lun; Hsu, Chin-Yu; Lee, Jheng-Syun; Fan, Hsin-Hsin; Liao, Chien-Neng
2018-05-31
Lattice-mismatch is an important factor for the heteroepitaxial growth of core-shell nanostructures. A large lattice-mismatch usually leads to a non-coherent interface or a polycrystalline shell layer. In this study, a conformal Ag layer is coated on Cu nanowires with dense nanoscale twin boundaries through a galvanic replacement reaction. Despite a large lattice mismatch between Ag and Cu (∼12.6%), the Ag shell replicates the twinning structure in Cu nanowires and grows epitaxially on the nanotwinned Cu nanowire. A twin-mediated growth mechanism is proposed to explain the epitaxy of high lattice-mismatch bimetallic systems in which the misfit dislocations are accommodated by coherent twin boundaries.
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Lee, Sooheyong; Williams, G. Jackson; Campana, Maria I.; Walko, Donald A.; Landahl, Eric C.
2016-01-01
Using a strain-rosette, we demonstrate the existence of transverse strain using time-resolved x-ray diffraction from multiple Bragg reflections in laser-excited bulk gallium arsenide. We find that anisotropic strain is responsible for a considerable fraction of the total lattice motion at early times before thermal equilibrium is achieved. Our measurements are described by a new model where the Poisson ratio drives transverse motion, resulting in the creation of shear waves without the need for an indirect process such as mode conversion at an interface. Using the same excitation geometry with the narrow-gap semiconductor indium antimonide, we detected coherent transverse acoustic oscillations at frequencies of several GHz. PMID:26751616
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Machon, P; Eschrig, M; Belzig, W
2013-01-25
We study thermal and charge transport in a three-terminal setup consisting of one superconducting and two ferromagnetic contacts. We predict that the simultaneous presence of spin filtering and of spin-dependent scattering phase shifts at each of the two interfaces will lead to very large nonlocal thermoelectric effects both in clean and in disordered systems. The symmetries of thermal and electric transport coefficients are related to fundamental thermodynamic principles by the Onsager reciprocity. Our results show that a nonlocal version of the Onsager relations for thermoelectric currents holds in a three-terminal quantum coherent ferromagnet-superconductor heterostructure including a spin-dependent crossed Andreev reflection and coherent electron transfer processes.
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Lin, Chun-Li; Kuo, Wen-Chuan; Chang, Yen-Hsiang; Yu, Jin-Jie; Lin, Yun-Chu
2014-08-01
This study investigates monitored micro-crack growth and damage in the ceramic/enamel adhesive interface using the acoustic emission (AE) technique with optical coherence tomography (OCT) under fatigue shear testing. Shear bond strength (SBS) was measured first with eight prepared ceramic/enamel adhesive specimens under static loads. The fatigue shear testing was performed with three specimens at each cyclic load according to a modified ISO14801 method, applying at 80%, 75%, 70%, and 65% of the SBS to monitor interface debonding. The number of cycles at each load was recorded until ceramic/enamel adhesive interface debonding occurred. The AE technique was used to detect micro-crack signals in static and fatigue shear bond tests. The results showed that the average SBS value in the static tests was 18.07 ± 1.72 MPa (mean ± standard deviation), expressed in Newton's at 56.77 ± 5.40N. The average number of fatigue cycles in which ceramic/enamel interface damage was detected in 80%, 75%, 70% and 65% of the SBS were 41, 410, 8141 and 76,541, respectively. The acoustic behavior varied according to the applied load level. Events were emitted during 65% and 70% fatigue tests. A good correlation was observed between the crack location in OCT images and the number of AE signal hits. The AE technique combined with OCT images as a pre-clinical assessment tool to determine the integrity of cemented load bearing restored ceramic material. Sustainable cyclic load stresses in ceramic/enamel bonded specimens were substantially lower than the measured SBS. Predicted S-N curve showed that the maximum endured load was 10.98 MPa (about 34.48 N) passing 10(6) fatigue cyclic. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Fletcher, L. B., E-mail: lbfletch@slac.stanford.edu; Galtier, E.; Gamboa, E. J.
2016-11-15
We present the first spectrally resolved measurements of x-rays scattered from cryogenic hydrogen jets in the single photon counting limit. The 120 Hz capabilities of the LCLS, together with a novel hydrogen jet design [J. B. Kim et al., Rev. Sci. Instrum. (these proceedings)], allow for the ability to record a near background free spectrum. Such high-dynamic-range x-ray scattering measurements enable a platform to study ultra-fast, laser-driven, heating dynamics of hydrogen plasmas. This measurement has been achieved using two highly annealed pyrolytic graphite crystal spectrometers to spectrally resolve 5.5 keV x-rays elastically and inelastically scattered from cryogenic hydrogen and focusedmore » on Cornell-SLAC pixel array detectors [S. Herrmann et al., Nucl. Instrum. Methods Phys. Res., Sect. A 718, 550 (2013)].« less
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Reed, Evan J.; Armstrong, Michael R.
2010-09-07
Strain waves of THz frequencies can coherently generate radiation when they propagate past an interface between materials with different piezoelectric coefficients. Such radiation is of detectable amplitude and contains sufficient information to determine the time-dependence of the strain wave with unprecedented subpicosecond, nearly atomic time and space resolution.
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Analysis of Technology for Compact Coherent Lidar
NASA Technical Reports Server (NTRS)
Amzajerdian, Farzin
1997-01-01
In view of the recent advances in the area of solid state and semiconductor lasers has created new possibilities for the development of compact and reliable coherent lidars for a wide range of applications. These applications include: Automated Rendezvous and Capture, wind shear and clear air turbulence detection, aircraft wake vortex detection, and automobile collision avoidance. The work performed by the UAH personnel under this Delivery Order, concentrated on design and analyses of a compact coherent lidar system capable of measuring range and velocity of hard targets, and providing air mass velocity data. The following is the scope of this work. a. Investigate various laser sources and optical signal detection configurations in support of a compact and lightweight coherent laser radar to be developed for precision range and velocity measurements of hard and fuzzy targets. Through interaction with MSFC engineers, the most suitable laser source and signal detection technique that can provide a reliable compact and lightweight laser radar design will be selected. b. Analyze and specify the coherent laser radar system configuration and assist with its optical and electronic design efforts. Develop a system design including its optical layout design. Specify all optical components and provide the general requirements of the electronic subsystems including laser beam modulator and demodulator drivers, detector electronic interface, and the signal processor. c. Perform a thorough performance analysis to predict the system measurement range and accuracy. This analysis will utilize various coherent laser radar sensitivity formulations and different target models.
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2009-05-01
shown in Fig. 1 was grown by molecular - beam epitaxy (MBE) on 3-inch semi-insulating GaAs substrates. AlGaSb was used as a buffer. AlSb was used as... beam epitaxy for low-power applications,” J. Vac. Sci. Technol. B. 24, pp. 2581-2585, 2006. [12] Y. C. Chou, L. J. Lee, J. M. Yang, M. D. Lange, P...passivation AlGaSb buffer Figure 1: Cross section of an AlSb/InAs HEMT device on a 3-inch GaAs substrate. The interface region between the
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Seton, Jacinta M.; Washington, Monique; Tomlinson, Suk C.; Phrasavath, Douangmala; Farrell, Karen R.; Goldstein, Barry
2016-01-01
Background A spinal cord injury disease management protocol (SCI DMP) was developed to address the unique medical, physical, functional, and psychosocial needs of those living with spinal cord injuries and disorders (SCI/D). The SCI DMP was piloted to evaluate DMP clinical content and to identify issues for broader implementation across the Veterans Affairs (VA) SCI System of Care. Methods Thirty-three patients with SCI/D from four VA SCI centers participated in a 6-month pilot. Patients received customized SCI DMP questions through a data messaging device (DMD). Nurse home telehealth care coordinators (HTCC) monitored responses and addressed clinical alerts daily. One site administered the Duke Severity of Illness (DUSOI) Checklist and Short Form-8 (SF-8™) to evaluate the changes in comorbidity severity and health-related quality of life while on the SCI DMP. Results Patients remained enrolled an average of 116 days, with a mean response rate of 56%. The average distance between patient's home and their VA SCI center was 59 miles. Feedback on SCI DMP content and the DMD included requests for additional clinical topics, changes in administration frequency, and adapting the DMD for functional impairments. Improvement in clinical outcomes was seen in a subset of patients enrolled on the SCI DMP. Conclusion SCI HTCCs and patients reported that the program was most beneficial for newly injured patients recently discharged from acute rehabilitation that live far from specialty SCI care facilities. SCI DMP content changes and broader implementation strategies are currently being evaluated based on lessons learned from the pilot. PMID:24617497
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Woo, Christine; Seton, Jacinta M; Washington, Monique; Tomlinson, Suk C; Phrasavath, Douangmala; Farrell, Karen R; Goldstein, Barry
2016-01-01
A spinal cord injury disease management protocol (SCI DMP) was developed to address the unique medical, physical, functional, and psychosocial needs of those living with spinal cord injuries and disorders (SCI/D). The SCI DMP was piloted to evaluate DMP clinical content and to identify issues for broader implementation across the Veterans Affairs (VA) SCI System of Care. Thirty-three patients with SCI/D from four VA SCI centers participated in a 6-month pilot. Patients received customized SCI DMP questions through a data messaging device (DMD). Nurse home telehealth care coordinators (HTCC) monitored responses and addressed clinical alerts daily. One site administered the Duke Severity of Illness (DUSOI) Checklist and Short Form-8 (SF-8™) to evaluate the changes in comorbidity severity and health-related quality of life while on the SCI DMP. Patients remained enrolled an average of 116 days, with a mean response rate of 56%. The average distance between patient's home and their VA SCI center was 59 miles. Feedback on SCI DMP content and the DMD included requests for additional clinical topics, changes in administration frequency, and adapting the DMD for functional impairments. Improvement in clinical outcomes was seen in a subset of patients enrolled on the SCI DMP. SCI HTCCs and patients reported that the program was most beneficial for newly injured patients recently discharged from acute rehabilitation that live far from specialty SCI care facilities. SCI DMP content changes and broader implementation strategies are currently being evaluated based on lessons learned from the pilot.
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Body-Machine Interfaces after Spinal Cord Injury: Rehabilitation and Brain Plasticity.
Seáñez-González, Ismael; Pierella, Camilla; Farshchiansadegh, Ali; Thorp, Elias B; Wang, Xue; Parrish, Todd; Mussa-Ivaldi, Ferdinando A
2016-12-19
The purpose of this study was to identify rehabilitative effects and changes in white matter microstructure in people with high-level spinal cord injury following bilateral upper-extremity motor skill training. Five subjects with high-level (C5-C6) spinal cord injury (SCI) performed five visuo-spatial motor training tasks over 12 sessions (2-3 sessions per week). Subjects controlled a two-dimensional cursor with bilateral simultaneous movements of the shoulders using a non-invasive inertial measurement unit-based body-machine interface. Subjects' upper-body ability was evaluated before the start, in the middle and a day after the completion of training. MR imaging data were acquired before the start and within two days of the completion of training. Subjects learned to use upper-body movements that survived the injury to control the body-machine interface and improved their performance with practice. Motor training increased Manual Muscle Test scores and the isometric force of subjects' shoulders and upper arms. Moreover, motor training increased fractional anisotropy (FA) values in the cingulum of the left hemisphere by 6.02% on average, indicating localized white matter microstructure changes induced by activity-dependent modulation of axon diameter, myelin thickness or axon number. This body-machine interface may serve as a platform to develop a new generation of assistive-rehabilitative devices that promote the use of, and that re-strengthen, the motor and sensory functions that survived the injury.
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Psychometric evaluation of the Spanish version of the MPI-SCI.
Soler, M D; Cruz-Almeida, Y; Saurí, J; Widerström-Noga, E G
2013-07-01
Postal surveys. To confirm the factor structure of the Spanish version of the MPI-SCI (MPI-SCI-S, Multidimensional Pain Inventory in the SCI population) and to test its internal consistency and construct validity in a Spanish population. Guttmann Institute, Barcelona, Spain. The MPI-SCI-S along with Spanish measures of pain intensity (Numerical Rating Scale), pain interference (Brief Pain Inventory), functional independence (Functional Independence Measure), depression (Beck Depression Inventory), locus of control (Multidimensional health Locus of Control), support (Functional Social Support Questionnaire (Duke-UNC)), psychological well-being (Psychological Global Well-Being Index) and demographic/injury characteristics were assessed in persons with spinal cord injury (SCI) and chronic pain (n=126). Confirmatory factor analysis suggested an adequate factor structure for the MPI-SCI-S. The internal consistency of the MPI-SCI-S subscales ranged from acceptable (r=0.66, Life Control) to excellent (r=0.94, Life Interference). All MPI-SCI-S subscales showed adequate construct validity, with the exception of the Negative and Solicitous Responses subscales. The Spanish version of the MPI-SCI is adequate for evaluating chronic pain impact following SCI in a Spanish-speaking population. Future studies should include additional measures of pain-related support in the Spanish-speaking SCI population.
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Infertility in Men with Spinal Cord Injury: Research and Treatment
Brackett, Nancy L.
2012-01-01
Spinal cord injury (SCI) occurs most often to young men. Following SCI, most men are infertile due to a combination of erectile dysfunction, ejaculatory dysfunction and semen abnormalities. Erectile dysfunction may be treated by the same therapies that are used in the general population. Similarly, the same treatments that are effective to assist conception in couples with non-SCI male factor patients are effective in assisting conception in SCI male-factor patients. The most apparent differences in male-factor symptoms between SCI and non-SCI patients are the high occurrences of anejaculation and atypical semen profiles in men with SCI. Methods available to assist ejaculation in men with SCI include penile vibratory stimulation and EEJ. Use of surgical sperm retrieval as the first line of treatment for anejaculation in men with SCI is controversial. Most men with SCI have a unique semen profile characterized by normal sperm concentration, but abnormally low sperm motility. Toxic substances in the semen contribute to this problem. Despite impaired sperm parameters, pregnancy outcomes using sperm from men with SCI are similar to pregnancy outcomes using sperm from non-SCI men. Future studies should focus on improving natural ejaculation and improving semen quality in these men. PMID:24278717
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Sullivan, Shannon D; Nash, Mark S; Tefera, Eshetu; Tinsley, Emily; Blackman, Marc R; Groah, Suzanne
2017-08-01
Spinal cord injury (SCI) triggers an "accelerated aging" process that may include development of hypogonadism, even among younger men with SCI; however, few studies have investigated the prevalence or etiology of hypogonadism in men with SCI. Young men with SCI also are at increased risk for developing metabolic dysfunction after injury, which may be exacerbated by concomitant testosterone (T) deficiency, thus identifying the prevalence and risk factors for T deficiency in men with SCI is important for their long-term health. To investigate the prevalence, risk factors, and etiology of T deficiency (hypogonadism) in otherwise-healthy men with chronic, motor complete SCI. Secondary cross-sectional analysis. Rehabilitation research centers in Washington, DC, and Miami, Florida. Men (n = 58) aged 18-45 years with chronic (≥1 year), motor complete SCI without comorbidities or use of testosterone therapy. Plasma concentrations of hormones were measured with standardized assays. Body composition was assessed with dual-energy x-ray absorptiometry scan. Serum total T and calculated free T. T deficiency was more common in men after SCI than in a matched cohort of similarly-aged men without SCI (25%, SCI versus 6.7%, non-SCI, P < .001). The risk of hypogonadism appeared to be increased in men with more extensive injury and with higher percent body fat. The majority of men with SCI with low T had low serum LH levels, suggesting that central suppression of the hypothalamic-pituitary-gonadal axis may be the most common etiology of hypogonadism after SCI. Hypogonadism is more common in young men with SCI than in similarly aged men without SCI, suggesting that SCI should be identified as a risk factor for T deficiency and that routine screening for hypogonadism should be performed in the SCI population. II. Copyright © 2017 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.
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Inoue, Tomoo; Lin, Amity; Ma, Xiaokui; McKenna, Stephen L.; Creasey, Graham H.; Manley, Geoffrey T.; Ferguson, Adam R.; Bresnahan, Jacqueline C.; Beattie, Michael S.
2015-01-01
A significant proportion (estimates range from 16–74%) of patients with spinal cord injury (SCI) have concomitant traumatic brain injury (TBI), and the combination often produces difficulties in planning and implementing rehabilitation strategies and drug therapies. For example, many of the drugs used to treat SCI may interfere with cognitive rehabilitation, and conversely drugs that are used to control seizures in TBI patients may undermine locomotor recovery after SCI. The current paper presents an experimental animal model for combined SCI and TBI to help drive mechanistic studies of dual diagnosis. Rats received a unilateral SCI (75 kdyn) at C5 vertebral level, a unilateral TBI (2.0 mm depth, 4.0 m/s velocity impact on the forelimb sensori-motor cortex), or both SCI + TBI. TBI was placed either contralateral or ipsilateral to the SCI. Behavioral recovery was examined using paw placement in a cylinder, grooming, open field locomotion, and the IBB cereal eating test. Over 6 weeks, in the paw placement test, SCI + contralateral TBI produced a profound deficit that failed to recover, but SCI + ipsilateral TBI increased the relative use of the paw on the SCI side. In the grooming test, SCI + contralateral TBI produced worse recovery than either lesion alone even though contralateral TBI alone produced no observable deficit. In the IBB forelimb test, SCI + contralateral TBI revealed a severe deficit that recovered in 3 weeks. For open field locomotion, SCI alone or in combination with TBI resulted in an initial deficit that recovered in 2 weeks. Thus, TBI and SCI affected forelimb function differently depending upon the test, reflecting different neural substrates underlying, for example, exploratory paw placement and stereotyped grooming. Concurrent SCI and TBI had significantly different effects on outcomes and recovery, depending upon laterality of the two lesions. Recovery of function after cervical SCI was retarded by the addition of a moderate TBI in the contralateral hemisphere in all tests, but forepaw placements were relatively increased by an ipsilateral TBI relative to SCI alone, perhaps due to the dual competing injuries influencing the use of both forelimbs. These findings emphasize the complexity of recovery from combined CNS injuries, and the possible role of plasticity and laterality in rehabilitation, and provide a start towards a useful preclinical model for evaluating effective therapies for combine SCI and TBI. PMID:23770071
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Inoue, Tomoo; Lin, Amity; Ma, Xiaokui; McKenna, Stephen L; Creasey, Graham H; Manley, Geoffrey T; Ferguson, Adam R; Bresnahan, Jacqueline C; Beattie, Michael S
2013-10-01
A significant proportion (estimates range from 16 to 74%) of patients with spinal cord injury (SCI) have concomitant traumatic brain injury (TBI), and the combination often produces difficulties in planning and implementing rehabilitation strategies and drug therapies. For example, many of the drugs used to treat SCI may interfere with cognitive rehabilitation, and conversely drugs that are used to control seizures in TBI patients may undermine locomotor recovery after SCI. The current paper presents an experimental animal model for combined SCI and TBI to help drive mechanistic studies of dual diagnosis. Rats received a unilateral SCI (75 kdyn) at C5 vertebral level, a unilateral TBI (2.0 mm depth, 4.0 m/s velocity impact on the forelimb sensori-motor cortex), or both SCI+TBI. TBI was placed either contralateral or ipsilateral to the SCI. Behavioral recovery was examined using paw placement in a cylinder, grooming, open field locomotion, and the IBB cereal eating test. Over 6weeks, in the paw placement test, SCI+contralateral TBI produced a profound deficit that failed to recover, but SCI+ipsilateral TBI increased the relative use of the paw on the SCI side. In the grooming test, SCI+contralateral TBI produced worse recovery than either lesion alone even though contralateral TBI alone produced no observable deficit. In the IBB forelimb test, SCI+contralateral TBI revealed a severe deficit that recovered in 3 weeks. For open field locomotion, SCI alone or in combination with TBI resulted in an initial deficit that recovered in 2 weeks. Thus, TBI and SCI affected forelimb function differently depending upon the test, reflecting different neural substrates underlying, for example, exploratory paw placement and stereotyped grooming. Concurrent SCI and TBI had significantly different effects on outcomes and recovery, depending upon laterality of the two lesions. Recovery of function after cervical SCI was retarded by the addition of a moderate TBI in the contralateral hemisphere in all tests, but forepaw placements were relatively increased by an ipsilateral TBI relative to SCI alone, perhaps due to the dual competing injuries influencing the use of both forelimbs. These findings emphasize the complexity of recovery from combined CNS injuries, and the possible role of plasticity and laterality in rehabilitation, and provide a start towards a useful preclinical model for evaluating effective therapies for combine SCI and TBI. Copyright © 2013 Elsevier Inc. All rights reserved.
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A spatial approach of magnitude-squared coherence applied to selective attention detection.
Bonato Felix, Leonardo; de Souza Ranaudo, Fernando; D'affonseca Netto, Aluizio; Ferreira Leite Miranda de Sá, Antonio Mauricio
2014-05-30
Auditory selective attention is the human ability of actively focusing in a certain sound stimulus while avoiding all other ones. This ability can be used, for example, in behavioral studies and brain-machine interface. In this work we developed an objective method - called Spatial Coherence - to detect the side where a subject is focusing attention to. This method takes into consideration the Magnitude Squared Coherence and the topographic distribution of responses among electroencephalogram electrodes. The individuals were stimulated with amplitude-modulated tones binaurally and were oriented to focus attention to only one of the stimuli. The results indicate a contralateral modulation of ASSR in the attention condition and are in agreement with prior studies. Furthermore, the best combination of electrodes led to a hit rate of 82% for 5.03 commands per minute. Using a similar paradigm, in a recent work, a maximum hit rate of 84.33% was achieved, but with a greater a classification time (20s, i.e. 3 commands per minute). It seems that Spatial Coherence is a useful technique for detecting focus of auditory selective attention. Copyright © 2014 Elsevier B.V. All rights reserved.
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Liyana-Arachchi, Thilanga P; Zhang, Zenghui; Ehrenhauser, Franz S; Avij, Paria; Valsaraj, Kalliat T; Hung, Francisco R
2014-01-01
Potential of mean force (PMF) calculations and molecular dynamics (MD) simulations were performed to investigate the properties of oil n-alkanes [i.e., n-pentadecane (C15), n-icosane (C20) and n-triacontane (C30)], as well as several surfactant species [i.e., the standard anionic surfactant sodium dodecyl sulfate (SDS), and three model dispersants similar to the Tween and Span species present in Corexit 9500A] at air/salt water interfaces. This study was motivated by the 2010 Deepwater Horizon (DWH) oil spill, and our simulation results show that, from the thermodynamic point of view, the n-alkanes and the model dispersants have a strong preference to remain at the air/salt water interface, as indicated by the presence of deep free energy minima at these interfaces. The free energy minimum of these n-alkanes becomes deeper as their chain length increases, and as the concentration of surfactant species at the interface increases. The n-alkanes tend to adopt a flat orientation and form aggregates at the bare air/salt water interface. When this interface is coated with surfactants, the n-alkanes tend to adopt more tilted orientations with respect to the vector normal to the interface. These simulation results are consistent with the experimental findings reported in the accompanying paper [Ehrenhauser et al., Environ. Sci.: Processes Impacts 2013, in press, (DOI: 10.1039/c3em00390f)]. The fact that these long-chain n-alkanes show a strong thermodynamic preference to remain at the air/salt water interfaces, especially if these interfaces are coated with surfactants, makes these species very likely to adsorb at the surface of bubbles or droplets and be ejected to the atmosphere by sea surface processes such as whitecaps (breaking waves) and bubble bursting. Finally, the experimental finding that more oil hydrocarbons are ejected when Corexit 9500A is present in the system is consistent with the deeper free energy minima observed for the n-alkanes at the air/salt water interface at increasing concentrations of surfactant species.
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NASA Astrophysics Data System (ADS)
Schmidt, C. M.; Bürgler, D. E.; Schaller, D. M.; Meisinger, F.; Güntherodt, H.-J.; Temst, K.
2001-01-01
A Cr(001)/Fe(001) superlattice with ten bilayers grown by molecular beam epitaxy on a Ag(001) substrate is studied by in situ scanning tunneling microscopy (STM) and ex situ x-ray diffraction (XRD). Layer-resolved roughness parameters determined from STM images taken in various stages of the superlattice fabrication are compared with average values reported in the literature or obtained from the fits of our XRD data. Good agreement is found for the rms roughnesses describing vertical roughness and for the lateral correlation lengths characterizing correlated as well as uncorrelated interface roughness if peculiarities of STM and XRD are taken into account. We discuss in detail (i) the possible differences between the STM topography of a free surface and the morphology of a subsequently formed interface, (ii) contributions due to chemical intermixing at the interfaces, (iii) the comparison of XRD parameters averaged over all interfaces versus layer-resolved STM parameters, and (iv) the question of the coherent field of view for the determination of rms values.
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Hu, Wei; Wang, Hongbo; Liu, Zhenfeng; Liu, Yanlu; Wang, Rong; Luo, Xiao; Huang, Yifei
2017-03-06
Oxidative damage induced-mitochondrial dysfunction and apoptosis has been widely studied in spinal cord injury (SCI). Lycopene, a polyunsaturated hydrocarbon, has the highest antioxidant capacity compared to the other carotenoids. However, the role of lycopene in SCI is unknown. In the present study, we evaluated the antioxidant effects of lycopene on mitochondrial dysfunction and apoptosis following T10 contusion SCI in rats. The rats were randomized into 5 groups: the sham group, the SCI group and the SCI pre-treated with lycopene (5, 10, or 20mg/kg) group. The SCI group showed increased malondialdehyde (MDA) content, decreased superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) ability, which indicated that SCI could induce oxidative damage. What's more, the SCI group showed decreased mRNA expression of cytochrome b and mitochondrial transcription factor A (Tfam), and decreased mitochondrial membrane potential (ΔYm), which indicated that SCI could induce mitochondrial dysfunction. Besides, the SCI group showed decreased protein expression of bcl-2 and mitochondrial cytochrome C, increased protein expression of cytosolic cytochrome C, cleaved caspase-9, cleaved caspase-3 and bax, and increased TUNEL-positive cell numbers, which indicated that SCI could induce cell apoptosis. Fortunately, the lycopene treatment significantly ameliorated oxidative damage, mitochondrial dysfunction and cell apoptosis via the reversion of those parameters described above in the dose of lycopene of 10 and 20mg/kg. In addition, lycopene significantly ameliorated the hind limb motor disturbances in the SCI+lyco10 group and the SCI+lyco20 group compared with the SCI group. These results suggested that lycopene administration could improve total antioxidant status and might have neuroprotective effects on SCI. Copyright © 2017 Elsevier B.V. All rights reserved.
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NASA Astrophysics Data System (ADS)
Kuo, K. S.; Rilee, M. L.
2017-12-01
Existing pathways for bringing together massive, diverse Earth Science datasets for integrated analyses burden end users with data packaging and management details irrelevant to their domain goals. The major data repositories focus on archival, discovery, and dissemination of products (files) in a standardized manner. End-users must download and then adapt these files using local resources and custom methods before analysis can proceed. This reduces scientific or other domain productivity, as scarce resources and expertise must be diverted to data processing. The Spatio-Temporal Adaptive Resolution Encoding (STARE) is a unifying scheme encoding geospatial and temporal information for organizing data on scalable computing/storage resources, minimizing expensive data transfers. STARE provides a compact representation that turns set-logic functions, e.g. conditional subsetting, into integer operations, that takes into account representative spatiotemporal resolutions of the data in the datasets, which is needed for data placement alignment of geo-spatiotemporally diverse data on massive parallel resources. Automating important scientific functions (e.g. regridding) and computational functions (e.g. data placement) allows scientists to focus on domain specific questions instead of expending their expertise on data processing. While STARE is not tied to any particular computing technology, we have used STARE for visualization and the SciDB array database to analyze Earth Science data on a 28-node compute cluster. STARE's automatic data placement and coupling of geometric and array indexing allows complicated data comparisons to be realized as straightforward database operations like "join." With STARE-enabled automation, SciDB+STARE provides a database interface, reducing costly data preparation, increasing the volume and variety of integrable data, and easing result sharing. Using SciDB+STARE as part of an integrated analysis infrastructure, we demonstrate the dramatic ease of combining diametrically different datasets, i.e. gridded (NMQ radar) vs. spacecraft swath (TRMM). SciDB+STARE is an important step towards a computational infrastructure for integrating and sharing diverse, complex Earth Science data and science products derived from them.
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Integrating Semantic Information in Metadata Descriptions for a Geoscience-wide Resource Inventory.
NASA Astrophysics Data System (ADS)
Zaslavsky, I.; Richard, S. M.; Gupta, A.; Valentine, D.; Whitenack, T.; Ozyurt, I. B.; Grethe, J. S.; Schachne, A.
2016-12-01
Integrating semantic information into legacy metadata catalogs is a challenging issue and so far has been mostly done on a limited scale. We present experience of CINERGI (Community Inventory of Earthcube Resources for Geoscience Interoperability), an NSF Earthcube Building Block project, in creating a large cross-disciplinary catalog of geoscience information resources to enable cross-domain discovery. The project developed a pipeline for automatically augmenting resource metadata, in particular generating keywords that describe metadata documents harvested from multiple geoscience information repositories or contributed by geoscientists through various channels including surveys and domain resource inventories. The pipeline examines available metadata descriptions using text parsing, vocabulary management and semantic annotation and graph navigation services of GeoSciGraph. GeoSciGraph, in turn, relies on a large cross-domain ontology of geoscience terms, which bridges several independently developed ontologies or taxonomies including SWEET, ENVO, YAGO, GeoSciML, GCMD, SWO, and CHEBI. The ontology content enables automatic extraction of keywords reflecting science domains, equipment used, geospatial features, measured properties, methods, processes, etc. We specifically focus on issues of cross-domain geoscience ontology creation, resolving several types of semantic conflicts among component ontologies or vocabularies, and constructing and managing facets for improved data discovery and navigation. The ontology and keyword generation rules are iteratively improved as pipeline results are presented to data managers for selective manual curation via a CINERGI Annotator user interface. We present lessons learned from applying CINERGI metadata augmentation pipeline to a number of federal agency and academic data registries, in the context of several use cases that require data discovery and integration across multiple earth science data catalogs of varying quality and completeness. The inventory is accessible at http://cinergi.sdsc.edu, and the CINERGI project web page is http://earthcube.org/group/cinergi
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Faller, Josef; Scherer, Reinhold; Friedrich, Elisabeth V. C.; Costa, Ursula; Opisso, Eloy; Medina, Josep; Müller-Putz, Gernot R.
2014-01-01
Individuals with severe motor impairment can use event-related desynchronization (ERD) based BCIs as assistive technology. Auto-calibrating and adaptive ERD-based BCIs that users control with motor imagery tasks (“SMR-AdBCI”) have proven effective for healthy users. We aim to find an improved configuration of such an adaptive ERD-based BCI for individuals with severe motor impairment as a result of spinal cord injury (SCI) or stroke. We hypothesized that an adaptive ERD-based BCI, that automatically selects a user specific class-combination from motor-related and non motor-related mental tasks during initial auto-calibration (“Auto-AdBCI”) could allow for higher control performance than a conventional SMR-AdBCI. To answer this question we performed offline analyses on two sessions (21 data sets total) of cue-guided, five-class electroencephalography (EEG) data recorded from individuals with SCI or stroke. On data from the twelve individuals in Session 1, we first identified three bipolar derivations for the SMR-AdBCI. In a similar way, we determined three bipolar derivations and four mental tasks for the Auto-AdBCI. We then simulated both, the SMR-AdBCI and the Auto-AdBCI configuration on the unseen data from the nine participants in Session 2 and compared the results. On the unseen data of Session 2 from individuals with SCI or stroke, we found that automatically selecting a user specific class-combination from motor-related and non motor-related mental tasks during initial auto-calibration (Auto-AdBCI) significantly (p < 0.01) improved classification performance compared to an adaptive ERD-based BCI that only used motor imagery tasks (SMR-AdBCI; average accuracy of 75.7 vs. 66.3%). PMID:25368546
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Fundamental limits to single-photon detection determined by quantum coherence and backaction
NASA Astrophysics Data System (ADS)
Young, Steve M.; Sarovar, Mohan; Léonard, François
2018-03-01
Single-photon detectors have achieved impressive performance and have led to a number of new scientific discoveries and technological applications. Existing models of photodetectors are semiclassical in that the field-matter interaction is treated perturbatively and time-separated from physical processes in the absorbing matter. An open question is whether a fully quantum detector, whereby the optical field, the optical absorption, and the amplification are considered as one quantum system, could have improved performance. Here we develop a theoretical model of such photodetectors and employ simulations to reveal the critical role played by quantum coherence and amplification backaction in dictating the performance. We show that coherence and backaction lead to trade-offs between detector metrics and also determine optimal system designs through control of the quantum-classical interface. Importantly, we establish the design parameters that result in a ideal photodetector with 100% efficiency, no dark counts, and minimal jitter, thus paving the route for next-generation detectors.
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Buker, Daniel Bueno; Oyarce, Cristóbal Castillo; Plaza, Raúl Smith
2018-01-01
Background: Spinal cord injury (SCI) above T6 is followed by a loss of sympathetic supraspinal control of the heart, disturbing the autonomic balance and increasing cardiovascular risk. Heart rate variability (HRV) is a widely used tool for assessing the cardiac autonomic nervous system and positive adaptations after regular exercise in able-bodied subjects. However, adaptations in SCI subjects are not well known. Objectives: To compare HRV between able-bodied and SCI subjects and analyze the effects of chronic and acute exercise on HRV in the SCI group. Methods: We searched MEDLINE, Embase, Web of Science, SciELO, and Google Scholar databases to July 2016. We selected English and Spanish observational or experimental studies reporting HRV after training or acute exercise in SCI patients. We also included studies comparing HRV in SCI individuals with able-bodied subjects. Animal studies and nontraumatic SCI studies were excluded. We screened 279 articles by title and abstract; of these, we fully reviewed 29 articles. Eighteen articles fulfilled criteria for inclusion in this study. Results: SCI individuals showed lower HRV values in the low frequency band compared to able-bodied subjects. Regular exercise improved HRV in SCI subjects, however time and intensity data were lacking. HRV decreases after an acute bout of exercise on SCI subjects, but recovery kinetics are unknown. Conclusion: HRV is affected following SCI. Able-bodied subjects and SCI individuals have different values of HRV. Acute bouts of exercise change HRV temporarily, and chronic exercise might improve autonomic balance in SCI.
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Overview of the Spinal Cord Injury--Quality of Life (SCI-QOL) measurement system.
Tulsky, David S; Kisala, Pamela A; Victorson, David; Tate, Denise G; Heinemann, Allen W; Charlifue, Susan; Kirshblum, Steve C; Fyffe, Denise; Gershon, Richard; Spungen, Ann M; Bombardier, Charles H; Dyson-Hudson, Trevor A; Amtmann, Dagmar; Kalpakjian, Claire Z; Choi, Seung W; Jette, Alan M; Forchheimer, Martin; Cella, David
2015-05-01
The Spinal Cord Injury--Quality of Life (SCI-QOL) measurement system was developed to address the shortage of relevant and psychometrically sound patient reported outcome (PRO) measures available for clinical care and research in spinal cord injury (SCI) rehabilitation. Using a computer adaptive testing (CAT) approach, the SCI-QOL builds on the Patient Reported Outcomes Measurement Information System (PROMIS) and the Quality of Life in Neurological Disorders (Neuro-QOL) initiative. This initial manuscript introduces the background and development of the SCI-QOL measurement system. Greater detail is presented in the additional manuscripts of this special issue. Classical and contemporary test development methodologies were employed. Qualitative input was obtained from individuals with SCI and clinicians through interviews, focus groups, and cognitive debriefing. Item pools were field tested in a multi-site sample (n=877) and calibrated using item response theory methods. Initial reliability and validity testing was performed in a new sample of individuals with traumatic SCI (n=245). Five Model SCI System centers and one Department of Veterans Affairs Medical Center across the United States. Adults with traumatic SCI. n/a n/a The SCI-QOL consists of 19 item banks, including the SCI-Functional Index banks, and 3 fixed-length scales measuring physical, emotional, and social aspects of health-related QOL (HRQOL). The SCI-QOL measurement system consists of psychometrically sound measures for individuals with SCI. The manuscripts in this special issue provide evidence of the reliability and initial validity of this measurement system. The SCI-QOL also links to other measures designed for a general medical population.
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Adhesion at Entangled Polymer Interfaces: A Unified Approach..
NASA Astrophysics Data System (ADS)
Wool, Richard
2006-03-01
A unified theory of fracture of polymer interfaces was developed which was based on the Rigidity Percolation model of fracture [R.P. Wool, J.Polym.Sci. Part A: Polym Phys., 43,168(2005)]. The polymer fractured critically when the normalized entanglement density p, approached the percolation threshold pc. The fracture energy was found to be G1c ˜ [p-pc]. When applied to interfaces of width X, containing an areal density σ of chains, each contributing L chain entanglements, the percolation term p ˜ σL/X and the percolation threshold was related to σc, Lc, or Xc. For welding of A/A symmetric interfaces, p = σL/X, and pc Lc/M 0, such that when σ/X ˜1/M for randomly distributed chain ends, p˜L ˜ (t/M)^1/2, G/G* = (t/τ*)^1/2, where the weld time τ* ˜ M. When the chain ends are segregated to the surface, σ is constant with time and G/G* = [t/τ*]^1/4. For sub-Tg welding, there exists a surface mobile layer (due to the critical Lindemann Atom fraction) of depth X ˜ 1/δT^ν such that G ˜ δT-2ν, where the critical exponent v = 0.8. For incompatible A/B interfaces of Helfand width d, normalized width w = d/Rge, and entanglement density Nent ˜ d/Le, p ˜ d such that, G1c ˜ [d-dc], G1c ˜ [w-1], and G ˜ [Nent-Nc]. For incompatible A/B interfaces reinforced by an areal density σ of compatibilizer chains, L and X are constant, p ˜ σ, pc ˜σc, such that G1c ˜ [σ-σc], which is in excellent agreement with experimental data.
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Suda, K J; Patel, U C; Sabzwari, R; Cao, L; Ramanathan, S; Hill, J N; Evans, C T
2016-11-01
Retrospective observational study of bacterial susceptibilities in Veterans with SCI/D as compared to a general patient population. The purpose of this project was to evaluate the prevalence and susceptibility of bacteria isolated from spinal cord injury and disorder (SCI/D) patients as compared with a general patient population and determine whether a SCI/D-specific antibiogram, a report of bacterial susceptibilities used to guide empiric antibiotic selection, would be a useful stewardship tool. Veterans Affairs Medical Center located in Cook county, IL, USA. Microbiology reports from 1 October 2012 to 30 September 2013 were compiled into a SCI/D-specific antibiogram and compared to a non-SCI/D antibiogram. Persons with positive cultures and SCI/D were younger and had a higher Charlson Index as compared to non-SCI/D patients (P<0.0001 for both). Five thousand one hundred and thirty-one unique isolate cultures were evaluated (SCI/D=23.0%). Frequencies of pathogens isolated in SCI/D and non-SCI/D differed. Methicillin-resistant Staphylococcus aureus occurred more frequently in SCI/D (27.8% vs 55.4%; P<0.0001). Gram-negatives had generally lower susceptibilities in SCI/D and a higher frequency of organisms producing extended-spectrum Beta-lactamases (17.6% vs 5.0%; P<0.0001), carbapenem-resistant Enterobacteriaceae (2.4% vs 0.5%; P<0.0001), carbapenem resistance (7.6% vs 2.4%; P<0.0001) and isolates resistant to ⩾3 antibiotic classes (60.7% vs 28.0%; P=0.0001). Different pathogens with poorer susceptibilities are isolated in SCI/D. Thus an SCI/D-specific antibiogram reflective of resistance patterns in these patients may increase the appropriateness of empiric antibiotic selection. The frequency of multi-drug resistant organisms in cultures obtained from patients with SCI/D is worrisome.
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Tian, Feng; Ni, Pengsheng; Mulcahey, M J; Hambleton, Ronald K; Tulsky, David; Haley, Stephen M; Jette, Alan M
2014-11-01
To use item response theory (IRT) methods to link scores from 2 recently developed contemporary functional outcome measures, the adult Spinal Cord Injury-Functional Index (SCI-FI) and the Pedi SCI (both the parent version and the child version). Secondary data analysis of the physical functioning items of the adult SCI-FI and the Pedi SCI instruments. We used a nonequivalent group design with items common to both instruments and the Stocking-Lord method for the linking. Linking was conducted so that the adult SCI-FI and Pedi SCI scaled scores could be compared. Community. This study included a total sample of 1558 participants. Pedi SCI items were administered to a sample of children (n=381) with SCI aged 8 to 21 years, and of parents/caregivers (n=322) of children with SCI aged 4 to 21 years. Adult SCI-FI items were administered to a sample of adults (n=855) with SCI aged 18 to 92 years. Not applicable. Five scales common to both instruments were included in the analysis: Wheelchair, Daily Routine/Self-care, Daily Routine/Fine Motor, Ambulation, and General Mobility functioning. Confirmatory factor analysis and exploratory factor analysis results indicated that the 5 scales are unidimensional. A graded response model was used to calibrate the items. Misfitting items were identified and removed from the item banks. Items that function differently between the adult and child samples (ie, exhibit differential item functioning) were identified and removed from the common items used for linking. Domain scores from the Pedi SCI instruments were transformed onto the adult SCI-FI metric. This IRT linking allowed estimation of adult SCI-FI scale scores based on Pedi SCI scale scores and vice versa; therefore, it provides clinicians with a means of tracking long-term functional data for children with an SCI across their entire lifespan. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.
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Virtual Teleoperation for Unmanned Aerial Vehicles
2012-01-24
Gilbert, S., “Wayfinder: Evaluating Multitouch Interaction in Supervisory Control of Unmanned Vehicles,” Proceedings of ASME 2nd World Conference on... interactive virtual reality environment that fuses available information into a coherent picture that can be viewed from multiple perspectives and scales...for multimodal interaction • Generally abstracted controller hardware and graphical interfaces facilitating deployment on a variety of VR platform
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Ultra-high efficiency moving wire combustion interface for on-line coupling of HPLC
Thomas, Avi T.; Ognibene, Ted; Daley, Paul; Turteltaub, Ken; Radousky, Harry; Bench, Graham
2011-01-01
We describe a 100% efficient moving-wire interface for on-line coupling of high performance liquid chromatography which transmits 100% of carbon in non-volatile analytes to a CO2 gas accepting ion source. This interface accepts a flow of analyte in solvent, evaporates the solvent, combusts the remaining analyte, and directs the combustion products to the instrument of choice. Effluent is transferred to a periodically indented wire by a coherent jet to increase efficiency and maintain peak resolution. The combustion oven is plumbed such that gaseous combustion products are completely directed to an exit capillary, avoiding the loss of combustion products to the atmosphere. This system achieves the near complete transfer of analyte at HPLC flow rates up to 125 μL/min at a wire speed of 6 cm/s. This represents a 30x efficiency increase and 8x maximum wire loading compared to the spray transfer technique used in earlier moving wire interfaces. PMID:22004428
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Proximity-induced superconductivity in all-silicon superconductor /normal-metal junctions
NASA Astrophysics Data System (ADS)
Chiodi, F.; Duvauchelle, J.-E.; Marcenat, C.; Débarre, D.; Lefloch, F.
2017-07-01
We have realized laser-doped all-silicon superconducting (S)/normal metal (N) bilayers of tunable thickness and dopant concentration. We observed a strong reduction of the bilayers' critical temperature when increasing the normal metal thickness, a signature of the highly transparent S/N interface associated to the epitaxial sharp laser doping profile. We extracted the interface resistance by fitting with the linearized Usadel equations, demonstrating a reduction of 1 order of magnitude from previous superconductor/doped Si interfaces. In this well-controlled crystalline system we exploited the low-resistance S/N interfaces to elaborate all-silicon lateral SNS junctions with long-range proximity effect. Their dc transport properties, such as the critical and retrapping currents, could be well understood in the diffusive regime. Furthermore, this work led to the estimation of important parameters in ultradoped superconducting Si, such as the Fermi velocity, the coherence length, or the electron-phonon coupling constant, fundamental to conceive all-silicon superconducting electronics.
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NASA Astrophysics Data System (ADS)
Stechmann, Guillaume; Zaefferer, Stefan; Raabe, Dierk
2018-06-01
The structure and energetics of coincidence site lattice grain boundaries (GB) in CdTe are investigated by mean of molecular statics simulations, using the Cd–Zn–Te bond-order potential (second iteration) developed by Ward et al (2012 Phys. Rev. B 86 245203; 2013 J. Mol. Modelling 19 5469–77). The effects of misorientation (Σ value) and interface plane are treated separately, complying with the critical need for full five-parameter characterization of GB. In addition, stoichiometric shifts, occurring between the inner interfaces and their adjacent atomic layers, are also predicted, revealing the energetic preference of Te-rich boundaries, opening opportunities for crystallography-based intrinsic interface doping. Our results also suggest that the intuitive assumption that Σ3 boundaries with low-indexed planes are more energetically favorable is often unfounded, except for coherent twins developing on {111} boundary planes. Therefore, Σ5, 7 or 9 boundaries, with lower interface energy than that of twin boundaries lying on different facets, are frequently encountered.
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Downconversion quantum interface for a single quantum dot spin and 1550-nm single-photon channel.
Pelc, Jason S; Yu, Leo; De Greve, Kristiaan; McMahon, Peter L; Natarajan, Chandra M; Esfandyarpour, Vahid; Maier, Sebastian; Schneider, Christian; Kamp, Martin; Höfling, Sven; Hadfield, Robert H; Forchel, Alfred; Yamamoto, Yoshihisa; Fejer, M M
2012-12-03
Long-distance quantum communication networks require appropriate interfaces between matter qubit-based nodes and low-loss photonic quantum channels. We implement a downconversion quantum interface, where the single photons emitted from a semiconductor quantum dot at 910 nm are downconverted to 1560 nm using a fiber-coupled periodically poled lithium niobate waveguide and a 2.2-μm pulsed pump laser. The single-photon character of the quantum dot emission is preserved during the downconversion process: we measure a cross-correlation g(2)(τ = 0) = 0.17 using resonant excitation of the quantum dot. We show that the downconversion interface is fully compatible with coherent optical control of the quantum dot electron spin through the observation of Rabi oscillations in the downconverted photon counts. These results represent a critical step towards a long-distance hybrid quantum network in which subsystems operating at different wavelengths are connected through quantum frequency conversion devices and 1.5-μm quantum channels.
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Averyanov, Dmitry V.; Karateeva, Christina G.; Karateev, Igor A.; Tokmachev, Andrey M.; Vasiliev, Alexander L.; Zolotarev, Sergey I.; Likhachev, Igor A.; Storchak, Vyacheslav G.
2016-01-01
Control and manipulation of the spin of conduction electrons in industrial semiconductors such as silicon are suggested as an operating principle for a new generation of spintronic devices. Coherent injection of spin-polarized carriers into Si is a key to this novel technology. It is contingent on our ability to engineer flawless interfaces of Si with a spin injector to prevent spin-flip scattering. The unique properties of the ferromagnetic semiconductor EuO make it a prospective spin injector into silicon. Recent advances in the epitaxial integration of EuO with Si bring the manufacturing of a direct spin contact within reach. Here we employ transmission electron microscopy to study the interface EuO/Si with atomic-scale resolution. We report techniques for interface control on a submonolayer scale through surface reconstruction. Thus we prevent formation of alien phases and imperfections detrimental to spin injection. This development opens a new avenue for semiconductor spintronics. PMID:26957146
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NASA Astrophysics Data System (ADS)
Schulz-Hildebrandt, Hinnerk; Sauer, Benjamin; Reinholz, Fred; Pieper, Mario; Mall, Markus; König, Peter; Huettmann, Gereon
2017-04-01
Failure in mucociliary clearance is responsible for severe diseases like cystic fibroses, primary ciliary dyskinesia or asthma. Visualizing the mucous transport in-vivo will help to understanding transport mechanisms as well as developing and validating new therapeutic intervention. However, in-vivo imaging is complicated by the need of high spatial and temporal resolution. Recently, we developed microscopy optical coherence tomography (mOCT) for non-invasive imaging of the liquid-air interface in intact murine trachea from its outside. Whereas axial resolution of 1.5 µm is achieved by the spectral width of supercontinuum light source, lateral resolution is limited by aberrations caused by the cylindric shape of the trachea and optical inhomogenities of the tissue. Therefore, we extended our mOCT by a deformable mirror for compensation of the probe induced aberrations. Instead of using a wavefront sensor for measuring aberrations, we harnessed optimization of the image quality to determine the correction parameter. With the aberration corrected mOCT ciliary function and mucus transport was measured in wild type and βENaC overexpressing mice, which served as a model for cystic fibrosis.
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Stacking fault energy of face-centered cubic metals: thermodynamic and ab initio approaches
NASA Astrophysics Data System (ADS)
Li, Ruihuan; Lu, Song; Kim, Dongyoo; Schönecker, Stephan; Zhao, Jijun; Kwon, Se Kyun; Vitos, Levente
2016-10-01
The formation energy of the interface between face-centered cubic (fcc) and hexagonal close packed (hcp) structures is a key parameter in determining the stacking fault energy (SFE) of fcc metals and alloys using thermodynamic calculations. It is often assumed that the contribution of the planar fault energy to the SFE has the same order of magnitude as the bulk part, and thus the lack of precise information about it can become the limiting factor in thermodynamic predictions. Here, we differentiate between the interfacial energy for the coherent fcc(1 1 1)/hcp(0 0 0 1) interface and the ‘pseudo-interfacial energy’ that enters the thermodynamic expression for the SFE. Using first-principles calculations, we determine the coherent and pseudo-interfacial energies for six elemental metals (Al, Ni, Cu, Ag, Pt, and Au) and three paramagnetic Fe-Cr-Ni alloys. Our results show that the two interfacial energies significantly differ from each other. We observe a strong chemistry dependence for both interfacial energies. The calculated pseudo-interfacial energies for the Fe-Cr-Ni steels agree well with the available literature data. We discuss the effects of strain on the description of planar faults via thermodynamic and ab initio approaches.
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2Q NMR of 2H2O ordering at solid interfaces
NASA Astrophysics Data System (ADS)
Krivokhizhina, Tatiana V.; Wittebort, R. J.
2014-06-01
Solvent ordering at an interface can be studied by multiple-quantum NMR. Quantitative studies of 2H2O ordering require clean double-quantum (2Q) filtration and an analysis of 2Q buildup curves that accounts for relaxation and, if randomly oriented samples are used, the distribution of residual couplings. A pulse sequence with absorption mode detection is extended for separating coherences by order and measuring relaxation times such as the 2Q filtered T2. Coherence separation is used to verify 2Q filtration and the 2Q filtered T2 is required to extract the coupling from the 2Q buildup curve when it is unresolved. With our analysis, the coupling extracted from the buildup curve in 2H2O hydrated collagen was equivalent to the resolved coupling measured in the usual 1D experiment and the 2Q to 1Q signal ratio was in accord with theory. Application to buildup curves from 2H2O hydrated elastin, which has an unresolved coupling, revealed a large increase in the 2Q signal upon mechanical stretch that is due to an increase in the ordered water fraction while changes in the residual coupling and T2 are small.
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Stacking fault energy of face-centered cubic metals: thermodynamic and ab initio approaches.
Li, Ruihuan; Lu, Song; Kim, Dongyoo; Schönecker, Stephan; Zhao, Jijun; Kwon, Se Kyun; Vitos, Levente
2016-10-05
The formation energy of the interface between face-centered cubic (fcc) and hexagonal close packed (hcp) structures is a key parameter in determining the stacking fault energy (SFE) of fcc metals and alloys using thermodynamic calculations. It is often assumed that the contribution of the planar fault energy to the SFE has the same order of magnitude as the bulk part, and thus the lack of precise information about it can become the limiting factor in thermodynamic predictions. Here, we differentiate between the interfacial energy for the coherent fcc(1 1 1)/hcp(0 0 0 1) interface and the 'pseudo-interfacial energy' that enters the thermodynamic expression for the SFE. Using first-principles calculations, we determine the coherent and pseudo-interfacial energies for six elemental metals (Al, Ni, Cu, Ag, Pt, and Au) and three paramagnetic Fe-Cr-Ni alloys. Our results show that the two interfacial energies significantly differ from each other. We observe a strong chemistry dependence for both interfacial energies. The calculated pseudo-interfacial energies for the Fe-Cr-Ni steels agree well with the available literature data. We discuss the effects of strain on the description of planar faults via thermodynamic and ab initio approaches.
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Characterization of Flow Dynamics and Reduced-Order Description of Experimental Two-Phase Pipe Flow
NASA Astrophysics Data System (ADS)
Viggiano, Bianca; SkjæRaasen, Olaf; Tutkun, Murat; Cal, Raul Bayoan
2017-11-01
Multiphase pipe flow is investigated using proper orthogonal decomposition for tomographic X-ray data, where holdup, cross sectional phase distributions and phase interface characteristics are obtained. Instantaneous phase fractions of dispersed flow and slug flow are analyzed and a reduced order dynamical description is generated. The dispersed flow displays coherent structures in the first few modes near the horizontal center of the pipe, representing the liquid-liquid interface location while the slug flow case shows coherent structures that correspond to the cyclical formation and breakup of the slug in the first 10 modes. The reconstruction of the fields indicate that main features are observed in the low order dynamical descriptions utilizing less than 1 % of the full order model. POD temporal coefficients a1, a2 and a3 show interdependence for the slug flow case. The coefficients also describe the phase fraction holdup as a function of time for both dispersed and slug flow. These flows are highly applicable to petroleum transport pipelines, hydroelectric power and heat exchanger tubes to name a few. The mathematical representations obtained via proper orthogonal decomposition will deepen the understanding of fundamental multiphase flow characteristics.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Li, D.Y.; Chen, L.Q.
Mechanical properties of Ni-based superalloys are strongly affected by the morphology, distribution, and size of {gamma}{prime} precipitates in the {gamma} matrix. The main purpose of this paper is to propose a continuum field approach for modeling the morphology and rafting kinetics of coherent precipitates under applied stresses. This approach can be used to simulate the temporal evolution of arbitrary morphologies and microstructures without any a priori assumption. Recently, the authors applied this approach to the selected variant growth in Ni-Ti alloys under applied stresses using an inhomogeneous modulus approximation. For the {gamma}{prime} precipitates in Ni-based superalloys, the eigenstrain is dilatational,more » and hence the {gamma}{prime} morphological evolution can be affected by applied stresses only when the elastic modulus is inhomogeneous. In the present work, the elastic inhomogeneity was taken into account by reformulating a sharp-interface elasticity theory developed recently by Khachaturyan et al. in terms of diffuse interfaces. Although the present work is for a {gamma}{prime} {minus} {gamma} system, this model is general in a sense that it can be applied to other alloy systems containing coherent ordered intermetallic precipitates with elastic inhomogeneity.« less
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NASA Astrophysics Data System (ADS)
Sinescu, Cosmin; Negrutiu, Meda Lavinia; Ionita, Ciprian; Topala, Florin; Petrescu, Emanuela; Rominu, Roxana; Pop, Daniela Maria; Marsavina, Liviu; Negru, Radu; Bradu, Adrian; Rominu, Mihai; Podoleanu, Adrian Gh.
2010-12-01
Imagistic investigation of the metal-ceramic crowns and fixed partial prostheses represent a very important issue in nowadays dentistry. At this time, in dental office, it is difficult or even impossible to evaluate a metal ceramic crown or bridge before setting it in the oral cavity. The possibilities of ceramic fractures are due to small fracture lines or material defects inside the esthetic layers. Material and methods: In this study 25 metal ceramic crowns and fixed partial prostheses were investigated by radiographic method (Rx), micro computer tomography (MicroCT) and optical coherence tomography (OCT) working in Time Domain, at 1300 nm. The OCT system contains two interferometers and one scanner. For each incident analysis a stuck made of 100 slices was obtain. These slices were used in order to obtain a 3D model of the ceramic interface. Results: RX and MicroCT are very powerful instruments that provide a good characterization of the dental construct. It is important to observe the reflections due to the metal infrastructure that could affect the evaluation of the metal ceramic crowns and bridges. The OCT investigations could complete the imagistic evaluation of the dental construct by offering important information when it is need it.
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NASA Astrophysics Data System (ADS)
Minamino, Takuya; Mine, Atsushi; Matsumoto, Mariko; Sugawa, Yoshihiko; Kabetani, Tomoshige; Higashi, Mami; Kawaguchi, Asuka; Ohmi, Masato; Awazu, Kunio; Yatani, Hirofumi
2015-10-01
No previous reports have observed inside the root canal using both optical coherence tomography (OCT) and x-ray microcomputed tomography (μCT) for the same sample. The purpose of this study was to clarify both OCT and μCT image properties from observations of the same root canal after resin core build-up treatment. As OCT allows real-time observation of samples, gap formation may be able to be shown in real time. A dual-cure, one-step, self-etch adhesive system bonding agent, and dual-cure resin composite core material were used in root canals in accordance with instructions from the manufacturer. The resulting OCT images were superior for identifying gap formation at the interface, while μCT images were better to grasp the tooth form. Continuous tomographic images from real-time OCT observation allowed successful construction of a video of the resin core build-up procedure. After 10 to 12 s of light curing, a gap with a clear new signal occurred at the root-core material interface, proceeding from the coronal side (6 mm from the cemento-enamel junction) to the apical side of the root.
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Quantum Optics with Near-Lifetime-Limited Quantum-Dot Transitions in a Nanophotonic Waveguide.
Thyrrestrup, Henri; Kiršanskė, Gabija; Le Jeannic, Hanna; Pregnolato, Tommaso; Zhai, Liang; Raahauge, Laust; Midolo, Leonardo; Rotenberg, Nir; Javadi, Alisa; Schott, Rüdiger; Wieck, Andreas D; Ludwig, Arne; Löbl, Matthias C; Söllner, Immo; Warburton, Richard J; Lodahl, Peter
2018-03-14
Establishing a highly efficient photon-emitter interface where the intrinsic linewidth broadening is limited solely by spontaneous emission is a key step in quantum optics. It opens a pathway to coherent light-matter interaction for, e.g., the generation of highly indistinguishable photons, few-photon optical nonlinearities, and photon-emitter quantum gates. However, residual broadening mechanisms are ubiquitous and need to be combated. For solid-state emitters charge and nuclear spin noise are of importance, and the influence of photonic nanostructures on the broadening has not been clarified. We present near-lifetime-limited linewidths for quantum dots embedded in nanophotonic waveguides through a resonant transmission experiment. It is found that the scattering of single photons from the quantum dot can be obtained with an extinction of 66 ± 4%, which is limited by the coupling of the quantum dot to the nanostructure rather than the linewidth broadening. This is obtained by embedding the quantum dot in an electrically contacted nanophotonic membrane. A clear pathway to obtaining even larger single-photon extinction is laid out; i.e., the approach enables a fully deterministic and coherent photon-emitter interface in the solid state that is operated at optical frequencies.
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Magnetic proximity effect at the interface between a cuprate superconductor and an oxide spin valve
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ovsyannikov, G. A., E-mail: gena@hitech.cplire.ru; Demidov, V. V.; Khaydukov, Yu. N.
2016-04-15
A heterostructure that consists of the YBa{sub 2}Cu{sub 3}O{sub 7–δ} cuprate superconductor and the SrRuO{sub 3}/La{sub 0.7}Sr{sub 0.3}MnO{sub 3} ruthenate/manganite spin valve is investigated using SQUID magnetometry, ferromagnetic resonance, and neutron reflectometry. It is shown that a magnetic moment is induced due to the magnetic proximity effect in the superconducting part of the heterostructure, while the magnetic moment in the composite ferromagnetic interlayer is suppressed. The magnetization emerging in the superconductor coincides in order of magnitude with the results of calculations taking into account the induced magnetic moment of Cu atoms because of orbital reconstruction at the interface between themore » superconductor and the ferromagnet, as well as with the results of the model taking into account the variations in the density of states at a distance on the order of the coherence length in the superconductor. The experimentally obtained characteristic penetration depth of the magnetic moment in the superconductor considerably exceeds the coherence length of the cuprate superconductor, which indicates the predominance of the mechanism of induced magnetic moment of Cu atoms.« less
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NASA Astrophysics Data System (ADS)
Paik, Seoyoung
A study of spin-dependent electronic transitions at the (111) oriented phosphorous doped crystalline silicon (c-Si) to silicon dioxide (SiO 2) interface is presented for [31P] = 1015 cm-3 and [31P] = 1016 cm -3 and a temperature range between T ≈ 5K and T ≈ 15K. Using pulsed electrically detected magnetic resonance (pEDMR), spin-dependent transitions involving 31P donor states and two different interface states are observed, namely (i) Pb centers which can be identified by their characteristic anisotropy and (ii) the E' center which is attributed to defects of the near interface SiO 2 bulk. Correlation measurements of the dynamics of spin-dependent recombination confirm that previously proposed transitions between 31P and the interface defects take place. The influence of these near interface transitions on the 31P donor spin coherence time T 2 as well as the donor spin-lattice relaxation time T 1 is then investigated by comparison of spin Hahn echo decay measurements obtained from conventional bulk sensitive pulsed electron paramagnetic resonance and surface sensitive pEDMR measurements, as well as surface sensitive electrically detected inversion recovery experiments. The measurements reveal that the T2 times of both interface states and 31P donor electrons spins in proximity of them are consistently shorter than the T1 times, and both T2 and T1 times of the near interface donors are reduced by several orders of magnitude from those in the bulk, at T ≤ 13 K. The T 2 times of the 31P donor electrons are in agreement with the prediction by De Sousa that they are limited by interface defect-induced field noise. To further investigate the dynamic properties of spin-dependent near interface processes, electrical detection of spin beat oscillation between resonantly induced spin-Rabi nutation is conducted at the phosphorous doped (1016cm-3) Si(111)/SiO2 interface. Predictions of Rabi beat oscillations based on several different spin-pair models are compared with measured Rabi beat nutation data. Due to the g-factor anisotropy of the Pb center (a silicon surface dangling bond), one can tune intra-pair Larmor frequency differences (Larmor separations) by orientation of the crystal with regard to an external magnetic field. Since Larmor separation governs the number of beating spin-pairs, crystal orientation can control the beat current. This is used to identify spin states that are paired by mutual electronic transitions. Based on the agreement between hypothesis and data, the experiments confirm the presence of the previously observed 31P-P b transition and the previously hypothesized P b to near interface SiO2 bulk state (E' center) transition.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Lee, Sooheyong; Williams, G. Jackson; Campana, Maria I.
Using a strain-rosette, we demonstrate the existence of transverse strain using time-resolved x-ray diffraction from multiple Bragg reflections in laser-excited bulk gallium arsenide. We find that anisotropic strain is responsible for a considerable fraction of the total lattice motion at early times before thermal equilibrium is achieved. Our measurements are described by a new model where the Poisson ratio drives transverse motion, resulting in the creation of shear waves without the need for an indirect process such as mode conversion at an interface. Finally, using the same excitation geometry with the narrow-gap semiconductor indium antimonide, we detected coherent transverse acousticmore » oscillations at frequencies of several GHz.« less
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Lee, Sooheyong; Williams, G. Jackson; Campana, Maria I.; ...
2016-01-11
Using a strain-rosette, we demonstrate the existence of transverse strain using time-resolved x-ray diffraction from multiple Bragg reflections in laser-excited bulk gallium arsenide. We find that anisotropic strain is responsible for a considerable fraction of the total lattice motion at early times before thermal equilibrium is achieved. Our measurements are described by a new model where the Poisson ratio drives transverse motion, resulting in the creation of shear waves without the need for an indirect process such as mode conversion at an interface. Finally, using the same excitation geometry with the narrow-gap semiconductor indium antimonide, we detected coherent transverse acousticmore » oscillations at frequencies of several GHz.« less
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Bazrafkan, Mahshid; Nikmehr, Banafsheh; Shahverdi, Abdolhossein; Hosseini, Seyed Reza; Hassani, Fatemeh; Poorhassan, Mahnaz; Mokhtari, Tahmineh; Abolhassani, Farid; Choobineh, Hamid; Beyer, Cordian; Hassanzadeh, Gholamreza
2017-10-16
The majority of male patients with spinal cord injury (SCI) suffer from infertility. Nucleotide-binding oligomerization domain-like receptors NOD-like receptors (NLRs) are a kind of receptors that corporate in the inflammasome complex. Recent studies have introduced the inflammasome as the responsible agent for secreting cytokines in semen. Reactive oxygen species (ROS) is one of the elements that trigger inflammasome activation. Genital infections in SCI can lead to ROS generation. We investigated the relation between lipid peroxidation and inflammasome complex activity in testicular tissue of SCI rats. Adult male rats (n=20), weighting 200-250 g, were included and divided into four groups: three experimental groups, including SCI1, SCI3, and SCI7, i.e. the rats were subjected to SCI procedure and sacrificed after one, three, and seven days, respectively and a control group. We performed a moderate, midline spinal contusion injury at thoracic level 10. The animals were anesthetized, and testes were collected for measurement of gene expression by real-time PCR. Caudal parts of epididymis were collected for malondialdehyde (MDA) measurement. No NLRP1a mRNA over expression was seen in the testes of control and SCI groups. After seven days from SCI surgery, NLRP3 mRNA expression was significantly increased in SCI7 animals (P≤0.05). There was a significant difference in MDA level in SCI7 versus control group, as well as SCI1 and SCI3 animals (P≤0.05). NLRP3 overexpression occurs due to the increased ROS production in testicular tissue of SCI rats.
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Bazrafkan, Mahshid; Nikmehr, Banafsheh; Shahverdi, Abdolhossein; Hosseini, Seyed Reza; Hassani, Fatemeh; Poorhassan, Mahnaz; Mokhtari, Tahmineh; Abolhassani, Farid; Choobineh, Hamid; Beyer, Cordian; Hassanzadeh, Gholamreza
2018-01-01
Background: The majority of male patients with spinal cord injury (SCI) suffer from infertility. Nucleotide-binding oligomerization domain-like receptors NOD-like receptors (NLRs) are a kind of receptors that corporate in the inflammasome complex. Recent studies have introduced the inflammasome as the responsible agent for secreting cytokines in semen. Reactive oxygen species (ROS) is one of the elements that trigger inflammasome activation. Genital infections in SCI can lead to ROS generation. We investigated the relation between lipid peroxidation and inflammasome complex activity in testicular tissue of SCI rats. Methods: Adult male rats (n=20), weighting 200-250 g, were included and divided into four groups: three experimental groups, including SCI1, SCI3, and SCI7, i.e. the rats were subjected to SCI procedure and sacrificed after one, three, and seven days, respectively and a control group. We performed a moderate, midline spinal contusion injury at thoracic level 10. The animals were anesthetized, and testes were collected for measurement of gene expression by real-time PCR. Caudal parts of epididymis were collected for malondialdehyde (MDA) measurement. Results: No NLRP1a mRNA overexpression was seen in the testes of control and SCI groups. After seven days from SCI surgery, NLRP3 mRNA expression was significantly increased in SCI7 animals (p ≤ 0.05). There was a significant difference in MDA level in SCI7 versus control group, as well as SCI1 and SCI3 animals (p ≤ 0.05). Conclusion: NLRP3 overexpression occurs due to the increased ROS production in testis tissue of SCI rats
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Overview of the Spinal Cord Injury – Quality of Life (SCI-QOL) measurement system
Tulsky, David S.; Kisala, Pamela A.; Victorson, David; Tate, Denise G.; Heinemann, Allen W.; Charlifue, Susan; Kirshblum, Steve C.; Fyffe, Denise; Gershon, Richard; Spungen, Ann M.; Bombardier, Charles H.; Dyson-Hudson, Trevor A.; Amtmann, Dagmar; Z. Kalpakjian, Claire; W. Choi, Seung; Jette, Alan M.; Forchheimer, Martin; Cella, David
2015-01-01
Context/Objective The Spinal Cord Injury – Quality of Life (SCI-QOL) measurement system was developed to address the shortage of relevant and psychometrically sound patient reported outcome (PRO) measures available for clinical care and research in spinal cord injury (SCI) rehabilitation. Using a computer adaptive testing (CAT) approach, the SCI-QOL builds on the Patient Reported Outcomes Measurement Information System (PROMIS) and the Quality of Life in Neurological Disorders (Neuro-QOL) initiative. This initial manuscript introduces the background and development of the SCI-QOL measurement system. Greater detail is presented in the additional manuscripts of this special issue. Design Classical and contemporary test development methodologies were employed. Qualitative input was obtained from individuals with SCI and clinicians through interviews, focus groups, and cognitive debriefing. Item pools were field tested in a multi-site sample (n = 877) and calibrated using item response theory methods. Initial reliability and validity testing was performed in a new sample of individuals with traumatic SCI (n = 245). Setting Five Model SCI System centers and one Department of Veterans Affairs Medical Center across the United States. Participants Adults with traumatic SCI. Interventions n/a Outcome Measures n/a Results The SCI-QOL consists of 19 item banks, including the SCI-Functional Index banks, and 3 fixed-length scales measuring physical, emotional, and social aspects of health-related QOL (HRQOL). Conclusion The SCI-QOL measurement system consists of psychometrically sound measures for individuals with SCI. The manuscripts in this special issue provide evidence of the reliability and initial validity of this measurement system. The SCI-QOL also links to other measures designed for a general medical population. PMID:26010962
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Circulating sclerostin is elevated in short-term and reduced in long-term SCI
Battaglino, Ricardo A.; Sudhakar, Supreetha; Lazzari, Antonio; Garshick, Eric; Zafonte, Ross; Morse, Leslie R.
2012-01-01
Spinal cord injury (SCI) causes profound bone loss due to muscle paralysis resulting in the inability to walk. Sclerostin, a Wnt signaling pathway antagonist produced by osteocytes, is a potent inhibitor of bone formation. Short-term studies in rodent models have demonstrated increased sclerostin in response to mechanical unloading that is reversed with reloading. Although sclerostin inhibition has been proposed as a potential therapy for bone loss, it is not known if sclerostin levels vary with duration of SCI in humans. We analyzed circulating sclerostin in 155 men with varying degrees of SCI who were 1 year or more post-injury. We report that sclerostin levels are greatest in subjects with short-term SCI (≤ 5 years post-injury) and decrease significantly over the first 5 years post-injury. There was no association between sclerostin and injury duration in subjects with long-term SCI (> 5 years post-injury). In subjects with long-term SCI, sclerostin levels were positively associated with lower extremity bone density and bone mineral content. These data suggest that sclerostin levels in SCI are initially increased after SCI in response to mechanical unloading. This response is time-limited and as bone loss progresses, circulating sclerostin is lowest in subjects with severe osteoporosis. These findings support a dual role for sclerostin after SCI: a therapeutic target in acute SCI, and a biomarker of osteoporosis severity in chronic SCI. PMID:22575440
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Learning by Creating and Exchanging Objects: The SCY Experience
ERIC Educational Resources Information Center
De Jong, Ton; Van Joolingen, Wouter R.; Giemza, Adam; Girault, Isabelle; Hoppe, Ulrich; Kindermann, Jorg; Kluge, Anders; Lazonder, Ard W.; Vold, Vibeke; Weinberger, Armin; Weinbrenner, Stefan; Wichmann, Astrid; Anjewierden, Anjo; Bodin, Marjolaine; Bollen, Lars; D'Ham, Cedric; Dolonen, Jan; Engler, Jan; Geraedts, Caspar; Grosskreutz, Henrik; Hovardas, Tasos; Julien, Rachel; Lechner, Judith; Ludvigsen, Sten; Matteman, Yuri; Meistadt, Oyvind; Naess, Bjorge; Ney, Muriel; Pedaste, Margus; Perritano, Anthony; Rinket, Marieke; Von Schlanbusch, Henrik; Sarapuu, Tago; Schulz, Florian; Sikken, Jakob; Slotta, Jim; Toussaint, Jeremy; Verkade, Alex; Wajeman, Claire; Wasson, Barbara; Zacharia, Zacharias C.; Van Der Zanden, Martine
2010-01-01
Science Created by You (SCY) is a project on learning in science and technology domains. SCY uses a pedagogical approach that centres around products, called "emerging learning objects" (ELOs) that are created by students. Students work individually and collaboratively in SCY-Lab (the general SCY learning environment) on "missions" that are guided…
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Federal Register 2010, 2011, 2012, 2013, 2014
2010-05-05
... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-70,235] SCI, LLC/Zener-Rectifier... Adjustment Assistance on October 19, 2009, applicable to workers of SCI LLC/Zener-Rectifier, Operations... Technical Resources were employed on-site at the Phoenix Arizona location of SCI LLC/Zener-Rectifier...
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Coherent Activity in Bilateral Parieto-Occipital Cortices during P300-BCI Operation.
Takano, Kouji; Ora, Hiroki; Sekihara, Kensuke; Iwaki, Sunao; Kansaku, Kenji
2014-01-01
The visual P300 brain-computer interface (BCI), a popular system for electroencephalography (EEG)-based BCI, uses the P300 event-related potential to select an icon arranged in a flicker matrix. In earlier studies, we used green/blue (GB) luminance and chromatic changes in the P300-BCI system and reported that this luminance and chromatic flicker matrix was associated with better performance and greater subject comfort compared with the conventional white/gray (WG) luminance flicker matrix. To highlight areas involved in improved P300-BCI performance, we used simultaneous EEG-fMRI recordings and showed enhanced activities in bilateral and right lateralized parieto-occipital areas. Here, to capture coherent activities of the areas during P300-BCI, we collected whole-head 306-channel magnetoencephalography data. When comparing functional connectivity between the right and left parieto-occipital channels, significantly greater functional connectivity in the alpha band was observed under the GB flicker matrix condition than under the WG flicker matrix condition. Current sources were estimated with a narrow-band adaptive spatial filter, and mean imaginary coherence was computed in the alpha band. Significantly greater coherence was observed in the right posterior parietal cortex under the GB than under the WG condition. Re-analysis of previous EEG-based P300-BCI data showed significant correlations between the power of the coherence of the bilateral parieto-occipital cortices and their performance accuracy. These results suggest that coherent activity in the bilateral parieto-occipital cortices plays a significant role in effectively driving the P300-BCI.
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Sensitivity of the SCI-FI/AT in Individuals With Traumatic Spinal Cord Injury.
Keeney, Tamra; Slavin, Mary; Kisala, Pamela; Ni, Pengsheng; Heinemann, Allen W; Charlifue, Susan; Fyffe, Denise C; Marino, Ralph J; Morse, Leslie R; Worobey, Lynn A; Tate, Denise; Rosenblum, David; Zafonte, Ross; Tulsky, David; Jette, Alan M
2018-03-31
To examine the ability of the Spinal Cord Injury-Functional Index/Assistive Technology (SCI-FI/AT) measure to detect change in persons with spinal cord injury (SCI). Multisite longitudinal (12-mo follow-up) study. Nine SCI Model Systems programs. Adults (N=165) with SCI enrolled in the SCI Model Systems database. Not applicable. SCI-FI/AT computerized adaptive test (CAT) (Basic Mobility, Self-Care, Fine Motor Function, Wheelchair Mobility, and/or Ambulation domains) completed at discharge from rehabilitation and 12 months after SCI. For each domain, effect size estimates and 95% confidence intervals were calculated for subgroups with paraplegia and tetraplegia. The demographic characteristics of the sample were as follows: 46% (n=76) individuals with paraplegia, 76% (n=125) male participants, 57% (n=94) used a manual wheelchair, 38% (n=63) used a power wheelchair, 30% (n=50) were ambulatory. For individuals with paraplegia, the Basic Mobility, Self-Care, and Ambulation domains of the SCI-FI/AT detected a significantly large amount of change; in contrast, the Fine Motor Function and Wheelchair Mobility domains detected only a small amount of change. For those with tetraplegia, the Basic Mobility, Fine Motor Function, and Self-Care domains detected a small amount of change whereas the Ambulation item domain detected a medium amount of change. The Wheelchair Mobility domain for people with tetraplegia was the only SCI-FI/AT domain that did not detect significant change. SCI-FI/AT CAT item banks detected an increase in function from discharge to 12 months after SCI. The effect size estimates for the SCI-FI/AT CAT vary by domain and level of lesion. Findings support the use of the SCI-FI/AT CAT in the population with SCI and highlight the importance of multidimensional functional measures. Copyright © 2018 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.
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Acute and Chronic Deficits in the Urinary Bladder after Spinal Contusion Injury in the Adult Rat
Herrera, Juan J.; Haywood-Watson, Ricky J.L.
2010-01-01
Abstract Traumatic spinal cord injury (SCI) permanently alters bladder function in humans. Hematuria and cystitis occur in both human SCI as well as in rodent models of SCI. Others have reported early SCI-dependent disruption to bladder uroepithelial integrity that results in increased permeability to urine and urine-borne substances. This can result in cystitis, or inflammation of the bladder, an ongoing pathological condition present throughout the chronic phase of SCI in humans. The goals of our study were twofold: (1) to begin to examine the inflammatory and molecular changes that occur within the bladder uroepithelium using a clinically-relevant spinal contusion model of injury, and (2) to assess whether these alterations continue into the chronic phase of SCI. Rats received either moderate SCI or sham surgery. Urine was collected from SCI and sham subjects over 7 days or at 7 months to assess levels of excreted proteins. Inflammation in the bladder wall was assessed via biochemical and immunohistochemical methods. Bladder tight junction proteins, mediators of uroepithelial integrity, were also measured in both the acute and chronic phases of SCI. Urine protein and hemoglobin levels rapidly increase following SCI. An SCI-dependent elevation in numbers of neutrophils within the bladder wall peaked at 48 h. Bladder tight junction proteins demonstrate a rapid but transient decrease as early as 2 h post-SCI. Surprisingly, elevated levels of urine proteins and significant deficits in bladder tight junction proteins could be detected in chronic SCI, suggesting that early pathological changes to the bladder may continue throughout the chronic phase of injury. PMID:19891526
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Joint inversions of two VTEM surveys using quasi-3D TDEM and 3D magnetic inversion algorithms
NASA Astrophysics Data System (ADS)
Kaminski, Vlad; Di Massa, Domenico; Viezzoli, Andrea
2016-05-01
In the current paper, we present results of a joint quasi-three-dimensional (quasi-3D) inversion of two versatile time domain electromagnetic (VTEM) datasets, as well as a joint 3D inversion of associated aeromagnetic datasets, from two surveys flown six years apart from one another (2007 and 2013) over a volcanogenic massive sulphide gold (VMS-Au) prospect in northern Ontario, Canada. The time domain electromagnetic (TDEM) data were inverted jointly using the spatially constrained inversion (SCI) approach. In order to increase the coherency in the model space, a calibration parameter was added. This was followed by a joint inversion of the total magnetic intensity (TMI) data extracted from the two surveys. The results of the inversions have been studied and matched with the known geology, adding some new valuable information to the ongoing mineral exploration initiative.
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Fletcher, L. B.; Zastrau, U.; Galtier, E.; ...
2016-08-15
Here, we present the first spectrally resolved measurements of x-rays scattered from cryogenic hydrogen jets in the single photon counting limit. The 120 Hz capabilities of the LCLS, together with a novel hydrogen jet design [J. B. Kim et al., Rev. Sci. Instrum. (these proceedings)], allow for the ability to record a near background free spectrum. Such high-dynamic-range x-ray scattering measurements enable a platform to study ultra-fast, laser-driven, heating dynamics of hydrogen plasmas. This measurement has been achieved using two highly annealed pyrolytic graphite crystal spectrometers to spectrally resolve 5.5 keV x-rays elastically and inelastically scattered from cryogenic hydrogen andmore » focused on Cornell-SLAC pixel array detectors [S. Herrmann et al., Nucl. Instrum. Methods Phys. Res., Sect. A 718, 550 (2013)].« less
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Near midplane scintillator-based fast ion loss detector on DIII-D.
Chen, X; Fisher, R K; Pace, D C; García-Muñoz, M; Chavez, J A; Heidbrink, W W; Van Zeeland, M A
2012-10-01
A new scintillator-based fast-ion loss detector (FILD) installed near the outer midplane of the plasma has been commissioned on DIII-D. This detector successfully measures coherent fast ion losses produced by fast-ion driven instabilities (≤500 kHz). Combined with the first FILD at ∼45° below the outer midplane [R. K. Fisher, et al., Rev. Sci. Instrum. 81, 10D307 (2010)], the two-detector system measures poloidal variation of losses. The phase space sensitivity of the new detector (gyroradius r(L) ∼ [1.5-8] cm and pitch angle α ∼ [35°-85°]) is calibrated using neutral beam first orbit loss measurements. Since fast ion losses are localized poloidally, having two FILDs at different poloidal locations allows for the study of losses over a wider range of plasma shapes and types of loss orbits.
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Quantum mechanical identification of quadrupolar plasmonic excited states in silver nanorods
Gieseking, Rebecca L.; Ratner, Mark A.; Schatz, George C.
2016-10-27
Quadrupolar plasmonic modes in noble metal nanoparticles have gained interest in recent years for various sensing applications. Although quantum mechanical studies have shown that dipolar plasmons can be modeled in terms of excited states where several to many excitations contribute coherently to the transition dipole moment, new approaches are needed to identify the quadrupolar plasmonic states. We show that quadrupolar states in Ag nanorods can be identified using the semiempirical INDO/SCI approach by examining the quadrupole moment of the transition density. The main longitudinal quadrupolar states occur at higher energies than the longitudinal dipolar states, in agreement with previous classicalmore » electrodynamics results, and have collective plasmonic character when the nanorods are sufficiently long. In conclusion, the ability to identify these states will make it possible to evaluate the differences between dipolar and quadrupolar plasmons that are relevant for sensing applications.« less
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Moore, Sarah A; Granger, Nicolas; Olby, Natasha J; Spitzbarth, Ingo; Jeffery, Nick D; Tipold, Andrea; Nout-Lomas, Yvette S; da Costa, Ronaldo C; Stein, Veronika M; Noble-Haeusslein, Linda J; Blight, Andrew R; Grossman, Robert G; Basso, D Michele; Levine, Jonathan M
2017-06-15
Translation of therapeutic interventions for spinal cord injury (SCI) from laboratory to clinic has been historically challenging, highlighting the need for robust models of injury that more closely mirror the human condition. The high prevalence of acute, naturally occurring SCI in pet dogs provides a unique opportunity to evaluate expeditiously promising interventions in a population of animals that receive diagnoses and treatment clinically in a manner similar to persons with SCI, while adhering to National Institutes of Health guidelines for scientific rigor and transparent reporting. In addition, pet dogs with chronic paralysis are often maintained long-term by their owners, offering a similarly unique population for study of chronic SCI. Despite this, only a small number of studies have used the clinical dog model of SCI. The Canine Spinal Cord Injury Consortium (CANSORT-SCI) was recently established by a group of veterinarians and basic science researchers to promote the value of the canine clinical model of SCI. The CANSORT-SCI group held an inaugural meeting November 20 and 21, 2015 to evaluate opportunities and challenges to the use of pet dogs in SCI research. Key challenges identified included lack of familiarity with the model among nonveterinary scientists and questions about how and where in the translational process the canine clinical model would be most valuable. In light of these, we review the natural history, outcome, and available assessment tools associated with canine clinical SCI with emphasis on their relevance to human SCI and the translational process.
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Eckerström, Marie; Berg, Anne Ingeborg; Nordlund, Arto; Rolstad, Sindre; Sacuiu, Simona; Wallin, Anders
2016-01-01
Subjective cognitive impairment (SCI) is a trigger for seeking health care in a possible preclinical phase of Alzheimer's disease (AD), although the characteristics of SCI need clarification. We investigated the prevalence of psychosocial stress, depressive symptoms and CSF AD biomarkers in SCI and MCI (mild cognitive impairment). Memory clinic patients (SCI: n = 90; age: 59.8 ± 7.6 years; MCI: n = 160; age: 63.7 ± 7.0 years) included in the Gothenburg MCI study were examined at baseline. Variables were analyzed using logistic regression with SCI as dependent variable. Stress was more prevalent in SCI (51.1%) than MCI (23.1%); p < 0.0005. SCI patients had more previous depressive symptoms (p = 0.006), but showed no difference compared to MCI patients considering current depressive symptoms. A positive CSF AD profile was present in 14.4% of SCI patients and 35.0% of MCI patients (p = 0.001). Stress (p = 0.002), previous stress/depressive symptoms (p = 0.006) and a negative CSF AD profile (p = 0.036) predicted allocation to the SCI group. Psychosocial stress is more prevalent in SCI than previously acknowledged. The high prevalence and long-term occurrence of stress/depressive symptoms in SCI in combination with a low prevalence of altered CSF AD biomarkers strengthens the notion that AD is not the most likely etiology of SCI. © 2016 S. Karger AG, Basel.
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NASA Astrophysics Data System (ADS)
Awasthi, Ankit; Anderson, William
2015-11-01
We have studied variation in structural inclination angle of coherent structures responding to a topography with abrupt spanwise heterogeneity. Recent results have shown that such a topography induces a turbulent secondary flow due to spanwise-wall normal heterogeneity of the Reynolds stresses (Anderson et al., 2015: J. Fluid Mech.). The presence of these spanwise alternating low and high momentum pathways (which are flanked by counter rotating, domain-scale vortices, Willingham et al., 2014: Phys. Fluids; Barros and Christensen, 2014: J. Fluid Mech.) are primarily due to the spanwise heterogeneity of the complex roughness under consideration. Results from the present research have been used to explore structural attributes of the hairpin packet paradigm in the presence of a turbulent secondary flow. Vortex visualization in the streamwise-wall normal plane above the crest (high drag) and trough (low drag) demonstrate variation in the inclination angle of coherent structures. The inclination angle of structures above the crest was approximately 45 degrees, much larger than the ``canonical'' value of 15 degrees. Thus, we present evidence that the hairpin packet concept is preserved - but modified - when a turbulent secondary flow is present. This work was supported by the Air Force Office of Sci. Research, Young Inv. Program (PM: Dr. R. Ponnoppan and Ms. E. Montomery) under Grant # FA9550-14-1-0394. Computational resources were provided by the Texas Adv. Comp. Center at Univ. of Texas.
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Lin, Hungyen; Dong, Yue; Shen, Yaochun; Zeitler, J Axel
2015-01-01
Spectral domain optical coherence tomography (OCT) has recently attracted a lot of interest in the pharmaceutical industry as a fast and non-destructive modality for quantification of thin film coatings that cannot easily be resolved with other techniques. Because of the relative infancy of this technique, much of the research to date has focused on developing the in-line measurement technique for assessing film coating thickness. To better assess OCT for pharmaceutical coating quantification, this paper evaluates tablets with a range of film coating thickness measured using OCT and terahertz pulsed imaging (TPI) in an off-line setting. In order to facilitate automated coating quantification for film coating thickness in the range of 30–200 μm, an algorithm that uses wavelet denoising and a tailored peak finding method is proposed to analyse each of the acquired A-scan. Results obtained from running the algorithm reveal an increasing disparity between the TPI and OCT measured intra-tablet variability when film coating thickness exceeds 100 μm. The finding further confirms that OCT is a suitable modality for characterising pharmaceutical dosage forms with thin film coatings, whereas TPI is well suited for thick coatings. © 2015 The Authors. Journal of Pharmaceutical Sciences published by Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 104:3377–3385, 2015 PMID:26284354
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Lin, Hungyen; Dong, Yue; Shen, Yaochun; Axel Zeitler, J
2015-10-01
Spectral domain optical coherence tomography (OCT) has recently attracted a lot of interest in the pharmaceutical industry as a fast and non-destructive modality for quantification of thin film coatings that cannot easily be resolved with other techniques. Because of the relative infancy of this technique, much of the research to date has focused on developing the in-line measurement technique for assessing film coating thickness. To better assess OCT for pharmaceutical coating quantification, this paper evaluates tablets with a range of film coating thickness measured using OCT and terahertz pulsed imaging (TPI) in an off-line setting. In order to facilitate automated coating quantification for film coating thickness in the range of 30-200μm, an algorithm that uses wavelet denoising and a tailored peak finding method is proposed to analyse each of the acquired A-scan. Results obtained from running the algorithm reveal an increasing disparity between the TPI and OCT measured intra-tablet variability when film coating thickness exceeds 100μm. The finding further confirms that OCT is a suitable modality for characterising pharmaceutical dosage forms with thin film coatings, whereas TPI is well suited for thick coatings. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 104:3377-3385, 2015. Copyright © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.
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Mejia, Christian R; Valladares-Garrido, Mario J; Miñan-Tapia, Armando; Serrano, Felipe T; Tobler-Gómez, Liz E; Pereda-Castro, William; Mendoza-Flores, Cynthia R; Mundaca-Manay, Maria Y; Valladares-Garrido, Danai
2017-01-01
Sci-Hub is a useful web portal for people working in science as it provides access to millions of free scientific articles. Satisfaction and usage should be explored in the Latino student population. The objective of this study was to evaluate the use, knowledge, and perception of the scientific contribution of Sci-Hub in medical students from Latin America. A multicenter, observational, analytical study was conducted in 6632 medical students from 6 countries in Latin America. We surveyed from a previously validated instrument, delving into knowledge, monthly average usage, satisfaction level, and perception of the scientific contributions provided by Sci-Hub. Frequencies and percentages are described, and generalized linear models were used to establish statistical associations. Only 19.2% of study participants knew of Sci-Hub and its function, while the median use was twice a month. 29.9% of Sci-Hub-aware participants claimed they always find the desired scientific information in their Sci-Hub search; 62.5% of participants affirmed that Sci-Hub contributes to scientific investigation; only 2.2% reported that Sci-Hub does not contribute to science. The majority of Latino students are not aware of Sci-Hub.
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Direct discontinuous Galerkin method and its variations for second order elliptic equations
Huang, Hongying; Chen, Zheng; Li, Jin; ...
2016-08-23
In this study, we study direct discontinuous Galerkin method (Liu and Yan in SIAM J Numer Anal 47(1):475–698, 2009) and its variations (Liu and Yan in Commun Comput Phys 8(3):541–564, 2010; Vidden and Yan in J Comput Math 31(6):638–662, 2013; Yan in J Sci Comput 54(2–3):663–683, 2013) for 2nd order elliptic problems. A priori error estimate under energy norm is established for all four methods. Optimal error estimate under L 2 norm is obtained for DDG method with interface correction (Liu and Yan in Commun Comput Phys 8(3):541–564, 2010) and symmetric DDG method (Vidden and Yan in J Comput Mathmore » 31(6):638–662, 2013). A series of numerical examples are carried out to illustrate the accuracy and capability of the schemes. Numerically we obtain optimal (k+1)th order convergence for DDG method with interface correction and symmetric DDG method on nonuniform and unstructured triangular meshes. An interface problem with discontinuous diffusion coefficients is investigated and optimal (k+1)th order accuracy is obtained. Peak solutions with sharp transitions are captured well. Highly oscillatory wave solutions of Helmholz equation are well resolved.« less
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Direct discontinuous Galerkin method and its variations for second order elliptic equations
DOE Office of Scientific and Technical Information (OSTI.GOV)
Huang, Hongying; Chen, Zheng; Li, Jin
In this study, we study direct discontinuous Galerkin method (Liu and Yan in SIAM J Numer Anal 47(1):475–698, 2009) and its variations (Liu and Yan in Commun Comput Phys 8(3):541–564, 2010; Vidden and Yan in J Comput Math 31(6):638–662, 2013; Yan in J Sci Comput 54(2–3):663–683, 2013) for 2nd order elliptic problems. A priori error estimate under energy norm is established for all four methods. Optimal error estimate under L 2 norm is obtained for DDG method with interface correction (Liu and Yan in Commun Comput Phys 8(3):541–564, 2010) and symmetric DDG method (Vidden and Yan in J Comput Mathmore » 31(6):638–662, 2013). A series of numerical examples are carried out to illustrate the accuracy and capability of the schemes. Numerically we obtain optimal (k+1)th order convergence for DDG method with interface correction and symmetric DDG method on nonuniform and unstructured triangular meshes. An interface problem with discontinuous diffusion coefficients is investigated and optimal (k+1)th order accuracy is obtained. Peak solutions with sharp transitions are captured well. Highly oscillatory wave solutions of Helmholz equation are well resolved.« less
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Effects of lengthscales and attractions on the collapse of hydrophobic polymers in water
Athawale, Manoj V.; Goel, Gaurav; Ghosh, Tuhin; Truskett, Thomas M.; Garde, Shekhar
2007-01-01
We present results from extensive molecular dynamics simulations of collapse transitions of hydrophobic polymers in explicit water focused on understanding effects of lengthscale of the hydrophobic surface and of attractive interactions on folding. Hydrophobic polymers display parabolic, protein-like, temperature-dependent free energy of unfolding. Folded states of small attractive polymers are marginally stable at 300 K and can be unfolded by heating or cooling. Increasing the lengthscale or decreasing the polymer–water attractions stabilizes folded states significantly, the former dominated by the hydration contribution. That hydration contribution can be described by the surface tension model, ΔG = γ(T)ΔA, where the surface tension, γ, is lengthscale-dependent and decreases monotonically with temperature. The resulting variation of the hydration entropy with polymer lengthscale is consistent with theoretical predictions of Huang and Chandler [Huang DM, Chandler D (2000) Proc Natl Acad Sci USA 97:8324–8327] that explain the blurring of entropy convergence observed in protein folding thermodynamics. Analysis of water structure shows that the polymer–water hydrophobic interface is soft and weakly dewetted, and is characterized by enhanced interfacial density fluctuations. Formation of this interface, which induces polymer folding, is strongly opposed by enthalpy and favored by entropy, similar to the vapor–liquid interface. PMID:17215352
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Controlling Hydrogen Embrittlement in Ultra-High Strength Steels
2006-06-01
this tempering temperature, (5) finely distributed, partly coherent M2C (where M = 75 at.% Cr, 13 Fe and 12 Mo) in martensite , averaging 2 nm...states in a complex precipitation hardened martensitic microstructure and is susceptible to severe hydrogen embrittlement (HE) at threshold stress...repartitions to interstitial sites proximate to the highly stressed crack tip and, subsequently, may retrap at martensitic lath interfaces to produce substantial
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ERIC Educational Resources Information Center
Bull, Susan; Kay, Judy
2016-01-01
The SMILI? (Student Models that Invite the Learner In) Open Learner Model Framework was created to provide a coherent picture of the many and diverse forms of Open Learner Models (OLMs). The aim was for SMILI? to provide researchers with a systematic way to describe, compare and critique OLMs. We expected it to highlight those areas where there…
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Band-Gap Engineering at a Semiconductor-Crystalline Oxide Interface
Jahangir-Moghadam, Mohammadreza; Ahmadi-Majlan, Kamyar; Shen, Xuan; ...
2015-02-09
The epitaxial growth of crystalline oxides on semiconductors provides a pathway to introduce new functionalities to semiconductor devices. Key to integrating the functionalities of oxides onto semiconductors is controlling the band alignment at interfaces between the two materials. Here we apply principles of band gap engineering traditionally used at heterojunctions between conventional semiconductors to control the band offset between a single crystalline oxide and a semiconductor. Reactive molecular beam epitaxy is used to realize atomically abrupt and structurally coherent interfaces between SrZr xTi 1-xO₃ and Ge, in which the band gap of the former is enhanced with Zr content x.more » We present structural and electrical characterization of SrZr xTi 1-xO₃-Ge heterojunctions and demonstrate a type-I band offset can be achieved. These results demonstrate that band gap engineering can be exploited to realize functional semiconductor crystalline oxide heterojunctions.« less
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Low Power, Low Mass, Modular, Multi-band Software-defined Radios
NASA Technical Reports Server (NTRS)
Haskins, Christopher B. (Inventor); Millard, Wesley P. (Inventor)
2013-01-01
Methods and systems to implement and operate software-defined radios (SDRs). An SDR may be configured to perform a combination of fractional and integer frequency synthesis and direct digital synthesis under control of a digital signal processor, which may provide a set of relatively agile, flexible, low-noise, and low spurious, timing and frequency conversion signals, and which may be used to maintain a transmit path coherent with a receive path. Frequency synthesis may include dithering to provide additional precision. The SDR may include task-specific software-configurable systems to perform tasks in accordance with software-defined parameters or personalities. The SDR may include a hardware interface system to control hardware components, and a host interface system to provide an interface to the SDR with respect to a host system. The SDR may be configured for one or more of communications, navigation, radio science, and sensors.
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Silicon-based products and solutions
NASA Astrophysics Data System (ADS)
Painchaud, Y.; Poulin, M.; Pelletier, F.; Latrasse, C.; Gagné, J.-F.; Savard, S.; Robidoux, G.; Picard, M.-.; Paquet, S.; Davidson, C.-.; Pelletier, M.; Cyr, M.; Paquet, C.; Guy, M.; Morsy-Osman, M.; Chagnon, M.; Plant, D. V.
2014-03-01
TeraXion started silicon photonics activities aiming at developing building blocks for new products and customized solutions. Passive and active devices have been developed including MMI couplers, power splitters, Bragg grating filters, high responsivity photodetectors, high speed modulators and variable optical attenuators. Packaging solutions including fiber attachment and hybrid integration using flip-chip were also developed. More specifically, a compact packaged integrated coherent receiver has been realized. Good performances were obtained as demonstrated by our system tests results showing transmission up to 4800 km with BER below hard FEC threshold. The package size is small but still limited by the electrical interface. Migrating to more compact RF interface would allow realizing the full benefit of this technology.
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Mulcahey, M J; Vogel, L C; Sheikh, M; Arango-Lasprilla, J C; Augutis, M; Garner, E; Hagen, E M; Jakeman, L B; Kelly, E; Martin, R; Odenkirchen, J; Scheel-Sailer, A; Schottler, J; Taylor, H; Thielen, C C; Zebracki, K
2017-04-01
In 2014, the adult spinal cord injury (SCI) common data element (CDE) recommendations were made available. This project was a review of the adult SCI CDE for relevance to children and youth with SCI. The objective of this study was to review the National Institute of Neurologic Disorders and Stroke (NINDS) adult SCI CDEs for relevance to children and youth with SCI. International. The pediatric working group consisted of international members with varied fields of expertise related to pediatric SCI. The group convened biweekly meetings for 6 months in 2015. All of the adult SCI CDEs were reviewed, evaluated and modified/created for four age groups: 0-5 years, 6-12 years, 13-15 years and 16-18 years. Whenever possible, results of published research studies were used to guide recommendations. In the absence of empirical support, grey literature and international content expert consensus were garnered. Existing pediatric NINDS CDEs and new CDEs were developed in areas where adult recommendations were not appropriate. After internal working group review of domain recommendations, these pediatric CDEs were vetted during a public review from November through December 2015. Version 1.0 of the pediatric SCI CDEs was posted in February 2016. The pediatric SCI CDEs are incorporated directly into the NINDS SCI CDE sets and can be found at https://commondataelements.ninds.nih.gov.
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Real-Time Strap Pressure Sensor System for Powered Exoskeletons
Tamez-Duque, Jesús; Cobian-Ugalde, Rebeca; Kilicarslan, Atilla; Venkatakrishnan, Anusha; Soto, Rogelio; Contreras-Vidal, Jose Luis
2015-01-01
Assistive and rehabilitative powered exoskeletons for spinal cord injury (SCI) and stroke subjects have recently reached the clinic. Proper tension and joint alignment are critical to ensuring safety. Challenges still exist in adjustment and fitting, with most current systems depending on personnel experience for appropriate individual fastening. Paraplegia and tetraplegia patients using these devices have impaired sensation and cannot signal if straps are uncomfortable or painful. Excessive pressure and blood-flow restriction can lead to skin ulcers, necrotic tissue and infections. Tension must be just enough to prevent slipping and maintain posture. Research in pressure dynamics is extensive for wheelchairs and mattresses, but little research has been done on exoskeleton straps. We present a system to monitor pressure exerted by physical human-machine interfaces and provide data about levels of skin/body pressure in fastening straps. The system consists of sensing arrays, signal processing hardware with wireless transmission, and an interactive GUI. For validation, a lower-body powered exoskeleton carrying the full weight of users was used. Experimental trials were conducted with one SCI and one able-bodied subject. The system can help prevent skin injuries related to excessive pressure in mobility-impaired patients using powered exoskeletons, supporting functionality, independence and better overall quality of life. PMID:25690551
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Towards bioelectronic logic (Conference Presentation)
NASA Astrophysics Data System (ADS)
Meredith, Paul; Mostert, Bernard; Sheliakina, Margarita; Carrad, Damon J.; Micolich, Adam P.
2016-09-01
One of the critical tasks in realising a bioelectronic interface is the transduction of ion and electron signals at high fidelity, and with appropriate speed, bandwidth and signal-to-noise ratio [1]. This is a challenging task considering ions and electrons (or holes) have drastically different physics. For example, even the lightest ions (protons) have mobilities much smaller than electrons in the best semiconductors, effective masses are quite different, and at the most basic level, ions are `classical' entities and electrons `quantum mechanical'. These considerations dictate materials and device strategies for bioelectronic interfaces alongside practical aspects such as integration and biocompatibility [2]. In my talk I will detail these `differences in physics' that are pertinent to the ion-electron transduction challenge. From this analysis, I will summarise the basic categories of device architecture that are possibilities for transducing elements and give recent examples of their realisation. Ultimately, transducing elements need to be combined to create `bioelectronic logic' capable of signal processing at the interface level. In this regard, I will extend the discussion past the single element concept, and discuss our recent progress in delivering all-solids-state logic circuits based upon transducing interfaces. [1] "Ion bipolar junction transistors", K. Tybrandt, K.C. Larsson, A. Richter-Dahlfors and M. Berggren, Proc. Natl Acad. Sci., 107, 9929 (2010). [2] "Electronic and optoelectronic materials and devices inspired by nature", P Meredith, C.J. Bettinger, M. Irimia-Vladu, A.B. Mostert and P.E. Schwenn, Reports on Progress in Physics, 76, 034501 (2013).
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Rohm, Martin; Schneiders, Matthias; Müller, Constantin; Kreilinger, Alex; Kaiser, Vera; Müller-Putz, Gernot R; Rupp, Rüdiger
2013-10-01
The bilateral loss of the grasp function associated with a lesion of the cervical spinal cord severely limits the affected individuals' ability to live independently and return to gainful employment after sustaining a spinal cord injury (SCI). Any improvement in lost or limited grasp function is highly desirable. With current neuroprostheses, relevant improvements can be achieved in end users with preserved shoulder and elbow, but missing hand function. The aim of this single case study is to show that (1) with the support of hybrid neuroprostheses combining functional electrical stimulation (FES) with orthoses, restoration of hand, finger and elbow function is possible in users with high-level SCI and (2) shared control principles can be effectively used to allow for a brain-computer interface (BCI) control, even if only moderate BCI performance is achieved after extensive training. The individual in this study is a right-handed 41-year-old man who sustained a traumatic SCI in 2009 and has a complete motor and sensory lesion at the level of C4. He is unable to generate functionally relevant movements of the elbow, hand and fingers on either side. He underwent extensive FES training (30-45min, 2-3 times per week for 6 months) and motor imagery (MI) BCI training (415 runs in 43 sessions over 12 months). To meet individual needs, the system was designed in a modular fashion including an intelligent control approach encompassing two input modalities, namely an MI-BCI and shoulder movements. After one year of training, the end user's MI-BCI performance ranged from 50% to 93% (average: 70.5%). The performance of the hybrid system was evaluated with different functional assessments. The user was able to transfer objects of the grasp-and-release-test and he succeeded in eating a pretzel stick, signing a document and eating an ice cream cone, which he was unable to do without the system. This proof-of-concept study has demonstrated that with the support of hybrid FES systems consisting of FES and a semiactive orthosis, restoring hand, finger and elbow function is possible in a tetraplegic end-user. Remarkably, even after one year of training and 415 MI-BCI runs, the end user's average BCI performance remained at about 70%. This supports the view that in high-level tetraplegic subjects, an initially moderate BCI performance cannot be improved by extensive training. However, this aspect has to be validated in future studies with a larger population. Copyright © 2013 Elsevier B.V. All rights reserved.
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Falci, Scott; Indeck, Charlotte; Barnkow, Dave
2018-06-01
OBJECTIVE Surgically created lesions of the spinal cord dorsal root entry zone (DREZ) to relieve central pain after spinal cord injury (SCI) have historically been performed at and cephalad to, but not below, the level of SCI. This study was initiated to investigate the validity of 3 proposed concepts regarding the DREZ in SCI central pain: 1) The spinal cord DREZ caudal to the level of SCI can be a primary generator of SCI below-level central pain. 2) Neuronal transmission from a DREZ that generates SCI below-level central pain to brain pain centers can be primarily through sympathetic nervous system (SNS) pathways. 3) Perceived SCI below-level central pain follows a unique somatotopic map of DREZ pain-generators. METHODS Three unique patients with both intractable SCI below-level central pain and complete spinal cord transection at the level of SCI were identified. All 3 patients had previously undergone surgical intervention to their spinal cords-only cephalad to the level of spinal cord transection-with either DREZ microcoagulation or cyst shunting, in failed attempts to relieve their SCI below-level central pain. Subsequent to these surgeries, DREZ lesioning of the spinal cord solely caudal to the level of complete spinal cord transection was performed using electrical intramedullary guidance. The follow-up period ranged from 1 1/2 to 11 years. RESULTS All 3 patients in this study had complete or near-complete relief of all below-level neuropathic pain. The analyzed electrical data confirmed and enhanced a previously proposed somatotopic map of SCI below-level DREZ pain generators. CONCLUSIONS The results of this study support the following hypotheses. 1) The spinal cord DREZ caudal to the level of SCI can be a primary generator of SCI below-level central pain. 2) Neuronal transmission from a DREZ that generates SCI below-level central pain to brain pain centers can be primarily through SNS pathways. 3) Perceived SCI below-level central pain follows a unique somatotopic map of DREZ pain generators.
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NASA Astrophysics Data System (ADS)
Gilliams, S. J.
2017-12-01
In line with the paradigm shift in Earth Observation of "Bringing the users to the data", ESA provides collaborative, virtual work environments giving access to EO data and tools, processors, and ICT resources through coherent interfaces. These coherent interfaces are categorized thematically, tailored to the related user communities and named Thematic Exploitation Platforms (TEP). The Food Security Thematic Exploitation Platform (FS-TEP) is the youngest out of seven TEPs and is developed in an agile mode in close coordination with its users. It will provide a "one stop platform" for the extraction of information from EO data for services in the food security sector mainly in Europe & Africa, allowing both access to EO data and processing of these data sets. Thereby it will foster smart, data-intensive agricultural and aquacultural applications in the scientific, private and public domain. The FS-TEP builds on a large and heterogeneous user community, spanning from application developers in agriculture to aquaculture, from small-scale farmers to agricultural industry, from public science to the finance and insurance sectors, from local and national administration to international agencies. To meet the requirements of these groups, the FS-TEP will provide different frontend interfaces. Service pilots will demonstrate the platform's ability to support agriculture and aquaculture with tailored EO based information services.The project team developing the FS-TEP and implementing pilot services during a 30 months period (started in April 2017) is led by Vista GmbH, Germany, supported by CGI Italy, VITO, Belgium, and Hatfield Consultants, Canada. It is funded by ESA under contract number 4000120074/17/I-EF.
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Sirepo: a web-based interface for physical optics simulations - its deployment and use at NSLS-II
NASA Astrophysics Data System (ADS)
Rakitin, Maksim S.; Chubar, Oleg; Moeller, Paul; Nagler, Robert; Bruhwiler, David L.
2017-08-01
"Sirepo" is an open source cloud-based software framework which provides a convenient and user-friendly web-interface for scientific codes such as Synchrotron Radiation Workshop (SRW) running on a local machine or a remote server side. SRW is a physical optics code allowing to simulate the synchrotron radiation from various insertion devices (undulators and wigglers) and bending magnets. Another feature of SRW is a support of high-accuracy simulation of fully- and partially-coherent radiation propagation through X-ray optical beamlines, facilitated by so-called "Virtual Beamline" module. In the present work, we will discuss the most important features of Sirepo/SRW interface with emphasis on their use for commissioning of beamlines and simulation of experiments at National Synchrotron Light Source II. In particular, "Flux through Finite Aperture" and "Intensity" reports, visualizing results of the corresponding SRW calculations, are being routinely used for commissioning of undulators and X-ray optical elements. Material properties of crystals, compound refractive lenses, and some other optical elements can be dynamically obtained for the desired photon energy from the databases publicly available at Argonne National Lab and at Lawrence Berkeley Lab. In collaboration with the Center for Functional Nanomaterials (CFN) of BNL, a library of samples for coherent scattering experiments has been implemented in SRW and the corresponding Sample optical element was added to Sirepo. Electron microscope images of artificially created nanoscale samples can be uploaded to Sirepo to simulate scattering patterns created by synchrotron radiation in different experimental schemes that can be realized at beamlines.
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Wu, Gary A; Bogie, Kath M
2013-08-01
Some individuals with spinal cord injury (SCI) remain pressure ulcer (PU) free whilst others experience a recurring cycle of tissue breakdown. Detailed analysis of gluteal muscle characteristics may provide insights to local tissue viability variability. The study hypothesis was that SCI individuals have altered muscle composition compared to able-bodied (AB). Ten AB and ten SCI received a supine pelvic CT scan, with contrast. Cross-sectional area (CSA) and overall muscle volume were derived using image analysis. Gluteal muscle tissue type was classified at the S2/S3 sacral vertebrae midpoint, the superior greater trochanters margin (GT) and the inferior ischial tuberosities margin (IT) using the linear transformation Hounsfield Unit scale. SCI gluteal CSA was less than for AB throughout the muscle, with the greatest relative atrophy at the IT (48%). Average AB gluteal volume was nearly double SCI. Eight SCI had over 20% infiltrative adipose tissue, three with over 50%. SCI gluteal CSA and intramuscular fat infiltration were significantly negatively correlated (p < 0.05). SCI IT axial slices showed less lean muscle and higher intramuscular fat infiltration than more proximally (p < 0.05). SCI gluteal muscle characteristics were indicative of impaired tissue viability. SCI disuse muscle atrophy was anticipated; the analytic approach further indicated that intramuscular atrophy was not uniform. SCI muscle composition showed increased proportions of both low density muscle and adipose tissue. CT scan with contrast is effective for gluteal muscle characterization. This assessment technique may contribute to determination of personalized risk for PU development and other secondary complications. Published by Elsevier Ltd.
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Granger, Nicolas; Olby, Natasha J.; Spitzbarth, Ingo; Jeffery, Nick D.; Tipold, Andrea; Nout-Lomas, Yvette S.; da Costa, Ronaldo C.; Stein, Veronika M.; Noble-Haeusslein, Linda J.; Blight, Andrew R.; Grossman, Robert G.; Basso, D. Michele; Levine, Jonathan M.
2017-01-01
Abstract Translation of therapeutic interventions for spinal cord injury (SCI) from laboratory to clinic has been historically challenging, highlighting the need for robust models of injury that more closely mirror the human condition. The high prevalence of acute, naturally occurring SCI in pet dogs provides a unique opportunity to evaluate expeditiously promising interventions in a population of animals that receive diagnoses and treatment clinically in a manner similar to persons with SCI, while adhering to National Institutes of Health guidelines for scientific rigor and transparent reporting. In addition, pet dogs with chronic paralysis are often maintained long-term by their owners, offering a similarly unique population for study of chronic SCI. Despite this, only a small number of studies have used the clinical dog model of SCI. The Canine Spinal Cord Injury Consortium (CANSORT-SCI) was recently established by a group of veterinarians and basic science researchers to promote the value of the canine clinical model of SCI. The CANSORT-SCI group held an inaugural meeting November 20 and 21, 2015 to evaluate opportunities and challenges to the use of pet dogs in SCI research. Key challenges identified included lack of familiarity with the model among nonveterinary scientists and questions about how and where in the translational process the canine clinical model would be most valuable. In light of these, we review the natural history, outcome, and available assessment tools associated with canine clinical SCI with emphasis on their relevance to human SCI and the translational process. PMID:28230415
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Angel, Sanne
2015-06-01
Having a partner is a strong factor in adaptation to the new life situation with a spinal cord injury (SCI). Still, more knowledge in detail about the partner's influences according to the experiences of individuals with SCI could contribute to the understanding of the situation after an injury. The aim of this phenomenological-hermeneutic article is to achieve a deeper understanding of nine individuals' experiences the first 2 years after SCI. In rehabilitation after SCI, the partner supported the SCI individual's life spirit by not giving up and by still seeing possibilities in the future. The partner reinforced the SCI individual's commitment to life by sharing experiences; providing love, trust, and hope; and giving priority to the best things in life for the SCI individual. This implied cohabitation providing concrete help and an intimacy that helped to cope with problems and anxieties and allowed SCI individuals the ability to self-realize. This promoted feelings of profound gratitude but also dependency. Thus, the SCI individual benefitted from the partner's support mentally and physically, which enabled a life that would not otherwise be possible.
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Global meaning in people with spinal cord injury: Content and changes
Littooij, Elsbeth; Widdershoven, Guy A.M.; Stolwijk-Swüste, Janneke M.; Doodeman, Suzan; Leget, Carlo J.W.; Dekker, Joost
2016-01-01
Background After spinal cord injury (SCI), people are confronted with abrupt discontinuity in almost all areas of life, leading to questions on how to live a meaningful life again. Global meaning refers to basic ideas and goals that guide people in giving meaning to their lives, in specific situations. Little is known about global meaning relating to SCI and whether global meaning changes after SCI. Purpose The purpose of this study was twofold: (i) to explore the content of global meaning of people with SCI, and (ii) to explore whether or not global meaning changes after SCI. Methods In-depth semi-structured interviews were conducted with 16 people with SCI. Interviews were analyzed according to the method of grounded theory. Results (i) Five aspects of global meaning were found: core values, relationships, worldview, identity and inner posture. (ii) Overall, little change in the content of global meaning was found after SCI; specific aspects of global meaning were foregrounded after SCI. Conclusion Five aspects of global meaning were found in people with SCI. Global meaning seems hardly subject to change. PMID:25615571
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Evaluation and Management of SCI-Associated Pain.
Saulino, Michael; Averna, Justin F
2016-09-01
Traumatic spinal cord injury (SCI) is a devastating neurological condition. Treatment of SCI-related pain is challenging for the treating physician, as normal neural pathways are disrupted. Patients with SCI consistently rate pain as one of the most difficult problems associated with their injury. SCI-related pain can be refractory and complete relief is often not possible. The multidimensional nature of SCI-related pain affects the neural system including autonomic nervous system deregulation and can alter metabolic and biochemical processes throughout the body. Co-morbid psychological illnesses such as depression and adjustment disorder are seen in a significant percentage of patients. Despite a better understanding of the underlying pain mechanisms and advances in procedural, pharmacologic, and non-pharmacologic therapies, treatment of pain after SCI remains elusive. This manuscript reviews the current evidence-based evaluation and management of the SCI patient with the overarching goal of providing appropriate and effective management of their pain. In particular, additional well-designed studies are needed to help elucidate effective treatments for SCI-related neuropathic pain in an effort to help provide these patients with better management of their pain and improve their quality of life.
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Yasuno, Fumihiko; Kazui, Hiroaki; Yamamoto, Akihide; Morita, Naomi; Kajimoto, Katsufumi; Ihara, Masafumi; Taguchi, Akihiko; Matsuoka, Kiwamu; Kosaka, Jun; Tanaka, Toshihisa; Kudo, Takashi; Takeda, Masatoshi; Nagatsuka, Kazuyuki; Iida, Hidehiro; Kishimoto, Toshifumi
2015-06-01
Subjective cognitive impairment (SCI) is a clinical state characterized by subjective cognitive deficits without cognitive impairment. To test the hypothesis that this state might involve dysfunction of self-referential processing mediated by cortical midline structures, we investigated abnormalities of functional connectivity in these structures in individuals with SCI using resting-state functional magnetic resonance imaging. We performed functional connectivity analysis for 23 individuals with SCI and 30 individuals without SCI. To reveal the pathophysiological basis of the functional connectivity change, we performed magnetic resonance-diffusion tensor imaging. Positron emission tomography-amyloid imaging was conducted in 13 SCI and 15 nonSCI subjects. Individuals with SCI showed reduced functional connectivity in cortical midline structures. Reduction in white matter connections was related to reduced functional connectivity, but we found no amyloid deposition in individuals with SCI. The results do not necessarily contradict the possibility that SCI indicates initial cognitive decrements, but imply that reduced functional connectivity in cortical midline structures contributes to overestimation of the experience of forgetfulness. Copyright © 2015 Elsevier Inc. All rights reserved.
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32 CFR 154.19 - Reinvestigation.
Code of Federal Regulations, 2011 CFR
2011-07-01
... to Sensitive Compartmented Information (SCI). Each individual having current access to SCI shall be... certain SCI duties may require very special compartmentation and other special security measures. In such... for continued SCI access. (h) Foreign nationals employed by DoD organizations overseas. Foreign...
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Kisala, Pamela A; Tulsky, David S; Pace, Natalie; Victorson, David; Choi, Seung W; Heinemann, Allen W
2015-05-01
To develop a calibrated item bank and computer adaptive test (CAT) to assess the effects of stigma on health-related quality of life in individuals with spinal cord injury (SCI). Grounded-theory based qualitative item development methods, large-scale item calibration field testing, confirmatory factor analysis, and item response theory (IRT)-based psychometric analyses. Five SCI Model System centers and one Department of Veterans Affairs medical center in the United States. Adults with traumatic SCI. SCI-QOL Stigma Item Bank A sample of 611 individuals with traumatic SCI completed 30 items assessing SCI-related stigma. After 7 items were iteratively removed, factor analyses confirmed a unidimensional pool of items. Graded Response Model IRT analyses were used to estimate slopes and thresholds for the final 23 items. The SCI-QOL Stigma item bank is unique not only in the assessment of SCI-related stigma but also in the inclusion of individuals with SCI in all phases of its development. Use of confirmatory factor analytic and IRT methods provide flexibility and precision of measurement. The item bank may be administered as a CAT or as a 10-item fixed-length short form and can be used for research and clinical applications.
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Development and psychometric characteristics of the SCI-QOL Pressure Ulcers scale and short form.
Kisala, Pamela A; Tulsky, David S; Choi, Seung W; Kirshblum, Steven C
2015-05-01
To develop a self-reported measure of the subjective impact of pressure ulcers on health-related quality of life (HRQOL) in individuals with spinal cord injury (SCI) as part of the SCI quality of life (SCI-QOL) measurement system. Grounded-theory based qualitative item development methods, large-scale item calibration testing, confirmatory factor analysis (CFA), and item response theory-based psychometric analysis. Five SCI Model System centers and one Department of Veterans Affairs medical center in the United States. Adults with traumatic SCI. SCI-QOL Pressure Ulcers scale. 189 individuals with traumatic SCI who experienced a pressure ulcer within the past 7 days completed 30 items related to pressure ulcers. CFA confirmed a unidimensional pool of items. IRT analyses were conducted. A constrained Graded Response Model with a constant slope parameter was used to estimate item thresholds for the 12 retained items. The 12-item SCI-QOL Pressure Ulcers scale is unique in that it is specifically targeted to individuals with spinal cord injury and at every stage of development has included input from individuals with SCI. Furthermore, use of CFA and IRT methods provide flexibility and precision of measurement. The scale may be administered in its entirety or as a 7-item "short form" and is available for both research and clinical practice.
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Kisala, Pamela A.; Tulsky, David S.; Pace, Natalie; Victorson, David; Choi, Seung W.; Heinemann, Allen W.
2015-01-01
Objective To develop a calibrated item bank and computer adaptive test (CAT) to assess the effects of stigma on health-related quality of life in individuals with spinal cord injury (SCI). Design Grounded-theory based qualitative item development methods, large-scale item calibration field testing, confirmatory factor analysis, and item response theory (IRT)-based psychometric analyses. Setting Five SCI Model System centers and one Department of Veterans Affairs medical center in the United States. Participants Adults with traumatic SCI. Main Outcome Measures SCI-QOL Stigma Item Bank Results A sample of 611 individuals with traumatic SCI completed 30 items assessing SCI-related stigma. After 7 items were iteratively removed, factor analyses confirmed a unidimensional pool of items. Graded Response Model IRT analyses were used to estimate slopes and thresholds for the final 23 items. Conclusions The SCI-QOL Stigma item bank is unique not only in the assessment of SCI-related stigma but also in the inclusion of individuals with SCI in all phases of its development. Use of confirmatory factor analytic and IRT methods provide flexibility and precision of measurement. The item bank may be administered as a CAT or as a 10-item fixed-length short form and can be used for research and clinical applications. PMID:26010973
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Mejia, Christian R.; Valladares-Garrido, Mario J.; Miñan-Tapia, Armando; Serrano, Felipe T.; Tobler-Gómez, Liz E.; Pereda-Castro, William; Mendoza-Flores, Cynthia R.; Mundaca-Manay, Maria Y.; Valladares-Garrido, Danai
2017-01-01
Introduction Sci-Hub is a useful web portal for people working in science as it provides access to millions of free scientific articles. Satisfaction and usage should be explored in the Latino student population. The objective of this study was to evaluate the use, knowledge, and perception of the scientific contribution of Sci-Hub in medical students from Latin America. Methodology A multicenter, observational, analytical study was conducted in 6632 medical students from 6 countries in Latin America. We surveyed from a previously validated instrument, delving into knowledge, monthly average usage, satisfaction level, and perception of the scientific contributions provided by Sci-Hub. Frequencies and percentages are described, and generalized linear models were used to establish statistical associations. Results Only 19.2% of study participants knew of Sci-Hub and its function, while the median use was twice a month. 29.9% of Sci-Hub-aware participants claimed they always find the desired scientific information in their Sci-Hub search; 62.5% of participants affirmed that Sci-Hub contributes to scientific investigation; only 2.2% reported that Sci-Hub does not contribute to science. Conclusion The majority of Latino students are not aware of Sci-Hub. PMID:28982181
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NASA Astrophysics Data System (ADS)
Huang, Bo-Jia; Kao, Li-Chi; Brahma, Sanjaya; Jeng, Yu-En; Chiu, Shang-Jui; Ku, Ching-Shun; Lo, Kuang-Yao
2017-05-01
Oxide- and defect-free metal/semiconductor interface is important to improve Ohmic contact for the suppression of electron scattering and the avoidance of an extrinsic surface state in estimating the barrier of the Schottky contact at the nanodevice interface. This study reports the growth mechanism of Zn quantum dots coherently grown on Si(1 1 1) and the physical phenomena of the crystalline, nonlinear optics, and the chemical states of Zn quantum dots. Epitaxial Zn quantum dots were coherently formed on a non-oxide Si(1 1 1) surface through the liquid- to solid-phase transformation as a result of pattern matching between the Zn(0 0 2) and Si(1 1 1) surfaces. The growth mechanism of constrained Zn quantum dots grown through strategic magnetron radio frequency sputtering is complex. Some factors, such as substrate temperature, hydrogen gas flow, and negative DC bias, influence the configuration of epitaxial Zn quantum dots. In particular, hydrogen gas plays an important role in reducing the ZnO+ and native oxide that is bombarded by accelerated ions, thereby enhancing the Zn ion surface diffusion. The reduction reaction can be inspected by distinguishing the chemical states of ZnO/Zn quantum dots from natural oxidation or the states of Zn 3d through the analysis of x-ray absorption near the edge structure spectrum. The complex growth mechanism can be systematically understood by analyzing a noncancelled anisotropic 3 m dipole from reflective second harmonic generation and inspecting the evolution between the Zn(0 0 2) and Zn(1 1 1) peaks of the collective ZnO/Zn quantum dots in synchrotron XRD.
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Quantum Control and Entanglement of Spins in Silicon Carbide
NASA Astrophysics Data System (ADS)
Klimov, Paul
Over the past several decades silicon carbide (SiC) has matured into a versatile material platform for high-power electronics and optoelectronic and micromechanical devices. Recent advances have also established SiC as a promising host for quantum technologies based on the spin of intrinsic defects, with the potential of leveraging existing device fabrication protocols alongside solid-state quantum control. Among these defects are the divacancies and related color centers, which have ground-state electron-spin triplets with coherence times as long as one millisecond and built-in optical interfaces operating near the telecommunication wavelengths. This rapidly developing field has prompted research into the SiC material host to understand how defect-bound electron spins interact with their surrounding nuclear spin bath. Although nuclear spins are a major source of decoherence in color-center spin systems, they are also a valuable resource since they can have coherence times that are orders of magnitude longer than electron spins. In this talk I will discuss our recent efforts to interface defect-bound electron spins in SiC with the nuclear spins of naturally occurring 29Si and 13C isotopic defects. I will discuss how the hyperfine interaction can be used to strongly initialize them, to coherently control them, to read them out, and to produce genuine electron-nuclear ensemble entanglement, all at ambient conditions. These demonstrations motivate further research into spins in SiC for prospective quantum technologies. In collaboration with A. Falk, D. Christle, K. Miao, H. Seo, V. Ivady, A. Gali, G. Galli, and D. D. Awschalom. This research was supported by the AFOSR, the NSF DMR-1306300, and the NSF Materials Research Science and Engineering Center.
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NASA Astrophysics Data System (ADS)
Huang, Shi-Hao; Wang, Shiang-Jiu; Tseng, Snow H.
2015-03-01
Optical coherence tomography (OCT) provides high resolution, cross-sectional image of internal microstructure of biological tissue. We use the Finite-Difference Time-Domain method (FDTD) to analyze the data acquired by OCT, which can help us reconstruct the refractive index of the biological tissue. We calculate the refractive index tomography and try to match the simulation with the data acquired by OCT. Specifically, we try to reconstruct the structure of melanin, which has complex refractive indices and is the key component of human pigment system. The results indicate that better reconstruction can be achieved for homogenous sample, whereas the reconstruction is degraded for samples with fine structure or with complex interface. Simulation reconstruction shows structures of the Melanin that may be useful for biomedical optics applications.
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Sleep disordered breathing in chronic spinal cord injury.
Sankari, Abdulghani; Bascom, Amy; Oomman, Sowmini; Badr, M Safwan
2014-01-15
Spinal cord injury (SCI) is associated with 2-5 times greater prevalence of sleep disordered breathing (SDB) than the general population. The contribution of SCI on sleep and breathing at different levels of injury using two scoring methods has not been assessed. The objectives of this study were to characterize the sleep disturbances in the SCI population and the associated physiological abnormalities using quantitative polysomnography and to determine the contribution of SCI level on the SDB mechanism. We studied 26 consecutive patients with SCI (8 females; age 42.5 ± 15.5 years; BMI 25.9 ± 4.9 kg/m2; 15 cervical and 11 thoracic levels) by spirometry, a battery of questionnaires and by attended polysomnography with flow and pharyngeal pressure measurements. Inclusion criteria for SCI: chronic SCI (> 6 months post injury), level T6 and above and not on mechanical ventilation. Ventilation, end-tidal CO2 (PETCO2), variability in minute ventilation (VI-CV) and upper airway resistance (RUA) were monitored during wakefulness and NREM sleep in all subjects. Each subject completed brief history and exam, Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), Berlin questionnaire (BQ) and fatigue severity scale (FSS). Sleep studies were scored twice, first using standard 2007 American Academy of Sleep Medicine (AASM) criteria and second using new 2012 recommended AASM criteria. Mean PSQI was increased to 10.3 ± 3.7 in SCI patients and 92% had poor sleep quality. Mean ESS was increased 10.4 ± 4.4 in SCI patients and excessive daytime sleepiness (ESS ≥ 10) was present in 59% of the patients. Daytime fatigue (FSS > 20) was reported in 96% of SCI, while only 46% had high-risk score of SDB on BQ. Forced vital capacity (FVC) in SCI was reduced to 70.5% predicted in supine compared to 78.5% predicted in upright positions (p < 0.05). Likewise forced expiratory volume in first second (FEV1) was 64.9% predicted in supine compared to 74.7% predicted in upright positions (p < 0.05). Mean AHI in SCI patients was 29.3 ± 25.0 vs. 20.0 ± 22.8 events/h using the new and conventional AASM scoring criteria, respectively (p < 0.001). SCI patients had SDB (AHI > 5 events/h) in 77% of the cases using the new AASM scoring criteria compared to 65% using standard conventional criteria (p < 0.05). In cervical SCI, VI decreased from 7.2 ± 1.6 to 5.5 ± 1.3 L/min, whereas PETCO2 and VI-CV, increased during sleep compared to thoracic SCI. The majority of SCI survivors have symptomatic SDB and poor sleep that may be missed if not carefully assessed. Decreased VI and increased PETCO2 during sleep in patients with cervical SCI relative to thoracic SCI suggests that sleep related hypoventilation may contribute to the pathogenesis SDB in patients with chronic cervical SCI.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Liu, Yuanfeng; Makongo, Julien P.A.; Page, Alexander
Energy filtering of charge carriers in a semiconducting matrix using atomically coherent nanostructures can lead to a significant improvement of the thermoelectric figure of merit of the resulting composite. In this work, several half-Heusler/full-Heusler (HH/FH) nanocomposites with general compositions Zr{sub 0.25}Hf{sub 0.75}Ni{sub 1+x}Sn{sub 1−y}Sb{sub y} (0≤x≤0.15 and y=0.005, 0.01 and 0.025) were synthesized in order to investigate the behavior of extrinsic carriers at the HH/FH interfaces. Electronic transport data showed that energy filtering of carriers at the HH/FH interfaces in Zr{sub 0.25}Hf{sub 0.75}Ni{sub 1+x}Sn{sub 1−y}Sb{sub y} samples strongly depends on the doping level (y value) as well as the energymore » levels occupied by impurity states in the samples. For example, it was found that carrier filtering at HH/FH interfaces is negligible in Zr{sub 0.25}Hf{sub 0.75}Ni{sub 1+x}Sn{sub 1−y}Sb{sub y} (y=0.01 and 0.025) composites where donor states originating from Sb dopant dominate electronic conduction. However, we observed a drastic decrease in the effective carrier density upon introduction of HH/FH interfaces for the mechanically alloyed Zr{sub 0.25}Hf{sub 0.75}Ni{sub 1+x}Sn{sub 0.995}Sb{sub 0.005} samples where donor states from unintentional Fe impurities contribute the largest fraction of conduction electrons. This work demonstrates the ability to synergistically integrate the concepts of doping and energy filtering through nanostructuring for the optimization of electronic transport in semiconductors. - Graphical abstract: Electronic transport in semiconducting half-Heusler (HH) matrices containing full-Heusler (FH) nanoinclusions strongly depends on the energy distribution of impurity states within the HH matrix with respect to the magnitude of the potential energy barrier at the HH/FH interfaces. - Highlights: • Coherent nanostructures enhanced thermoelectric behavior of half-Heusler alloys. • Nanostructures act as energy filter of carriers at the HH/FH interfaces. • Carrier filtering depends on the energy levels of impurity states in the samples.« less
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Hill, Jennifer N; Smith, Bridget M; Weaver, Frances M; Nazi, Kim M; Thomas, Florian P; Goldstein, Barry; Hogan, Timothy P
2018-05-01
Although personal health record (PHR) portals are designed for patients, healthcare providers are a key influence in how patients use their features and realize benefits from them. A few studies have examined provider attitudes toward PHR portals, but none have focused on those who care for individuals with spinal cord injuries and disorders (SCI/D). We characterize SCI/D provider perspectives of PHR portals, including perceived advantages and disadvantages of PHR portal use in SCI/D care. Cross-sectional; semi-structured interviews. Spinal Cord Injury (SCI) Centers in the Veterans Health Administration. Twenty-six SCI/D healthcare providers. None. Perceived advantages and disadvantages of PHR portals. The complex situations of individuals with SCI/D shaped provider perspectives of PHR portals and their potential role in practice. Perceived advantages of PHR portal use in SCI/D care included the ability to coordinate information and care, monitor and respond to outpatient requests, support patient self-management activities, and provide reliable health information to patients. Perceived disadvantages of PHR portal use in SCI/D care included concerns about the quality of patient-generated health data, other potential liabilities for providers and workload burden, and the ability of individuals with SCI/D to understand clinical information accessed through a portal. Our study highlights advantages and disadvantages that should be considered when promoting engagement of SCI/D healthcare providers in use of PHR portals, and portal features that may have the most utility in SCI/D care.
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Circulating sclerostin is elevated in short-term and reduced in long-term SCI.
Battaglino, Ricardo A; Sudhakar, Supreetha; Lazzari, Antonio A; Garshick, Eric; Zafonte, Ross; Morse, Leslie R
2012-09-01
Spinal cord injury (SCI) causes profound bone loss due to muscle paralysis resulting in the inability to walk. Sclerostin, a Wnt signaling pathway antagonist produced by osteocytes, is a potent inhibitor of bone formation. Short-term studies in rodent models have demonstrated increased sclerostin in response to mechanical unloading that is reversed with reloading. Although sclerostin inhibition has been proposed as a potential therapy for bone loss, it is not known if sclerostin levels vary with duration of SCI in humans. We analyzed circulating sclerostin in 155 men with varying degrees of SCI who were 1 year or more post-injury. We report that sclerostin levels are greatest in subjects with short-term SCI (≤5 years post-injury) and decrease significantly over the first 5 years post-injury. There was no association between sclerostin and injury duration in subjects with long-term SCI (>5 years post-injury). In subjects with long-term SCI, sclerostin levels were positively associated with lower extremity bone density and bone mineral content. These data suggest that sclerostin levels are initially increased after SCI in response to mechanical unloading. This response is time-limited and as bone loss progresses, circulating sclerostin is lowest in subjects with severe osteoporosis. These findings support a dual role for sclerostin after SCI: a therapeutic target in acute SCI, and a biomarker of osteoporosis severity in chronic SCI. Copyright © 2012 Elsevier Inc. All rights reserved.
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Bang, Woo-Seok; Kim, Kyoung-Tae; Seo, Ye Jin; Cho, Dae-Chul; Sung, Joo-Kyung; Kim, Chi Heon
2018-01-01
Objective To investigates the effect of curcumin on proliferation of spinal cord neural stem/progenitor cells (SC-NSPCs) and functional outcome in a rat spinal cord injury (SCI) model. Methods Sixty adult male Sprague-Dawley rats were randomly and blindly allocated into three groups (sham control group; curcumin treated group after SCI; vehicle treated group after SCI). Functional recovery was evaluated by the Basso, Beattie, and Bresnahan (BBB) scale during 6 weeks after SCI. The expression of SC-NSPC proliferation and astrogliosis were analyzed by nestin/Bromodeoxyuridine (BrdU) and Glial fibrillary acidic protein (GFAP) staining. The injured spinal cord was then examined histologically, including quantification of cavitation. Results The BBB score of the SCI-curcumin group was better than that of SCI-vehicle group up to 14 days (p<0.05). The co-immunoreactivity of nestin/BrdU in the SCI-curcumin group was much higher than that of the SCI-vehicle group 1 week after surgery (p<0.05). The GFAP immunoreactivity of the SCI-curcumin group was remarkably lower than that of the SCI-vehicle group 4 weeks after surgery (p<0.05). The lesion cavity was significantly reduced in the curcumin group as compared to the control group (p<0.05). Conclusion These results indicate that curcumin could increase the expression of SC-NSPCs, and reduce the activity of reactive astrogliosis and lesion cavity. Consequently curcumin could improve the functional recovery after SCI via SC-NSPC properties. PMID:29354231
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Spinal Cord Injury Impairs Cardiovascular Capacity in Elite Wheelchair Rugby Athletes.
Gee, Cameron M; Currie, Katharine D; Phillips, Aaron A; Squair, Jordan W; Krassioukov, Andrei V
2017-12-19
To examine differences in heart rate (HR) responses during international wheelchair rugby competition between athletes with and without a cervical spinal cord injury (SCI) and across standardized sport classifications. Observational study. The 2015 Parapan American Games wheelchair rugby competition. Forty-three male athletes (31 ± 8 years) with a cervical SCI (n = 32) or tetraequivalent impairment (non-SCI, n = 11). Average and peak HR (HRavg and HRpeak, respectively). To characterize HR responses in accordance with an athletes' International Wheelchair Rugby Federation (IWRF) classification, we separated athletes into 3 groups: group I (IWRF classification 0.5-1.5, n = 15); group II (IWRF classification 2.0, n = 15); and group III (IWRF classification 2.5-3.5, n = 13). Athletes with SCI had lower HRavg (111 ± 14 bpm vs 155 ± 13 bpm) and HRpeak (133 ± 12 bpm vs 178 ± 13 bpm) compared with non-SCI (both P < 0.001). Average HR was higher in group III than in I (136 ± 25 bpm vs 115 ± 20 bpm, P = 0.045); however, SCI athletes showed no difference in HRavg or HRpeak between groups. Within group III, SCI athletes had lower HRavg (115 ± 6 bpm vs 160 ± 8 bpm) and HRpeak (135 ± 11 bpm vs 183 ± 11 bpm) than non-SCI athletes (both P < 0.001). This study is the first to demonstrate attenuated HR responses during competition in SCI compared with non-SCI athletes, likely due to injury to spinal autonomic pathways. Among athletes with SCI, IWRF classification was not related to differences in HR. Specific assessment of autonomic function after SCI may be able to predict HR during competition and consideration of autonomic impairments may improve the classification process.
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Sweet, Shane N; Noreau, Luc; Leblond, Jean; Dumont, Frédéric S
2014-01-01
Understanding the factors that can predict greater quality of life (QoL) is important for adults with spinal cord injury (SCI), given that they report lower levels of QoL than the general population. To build a conceptual model linking SCI-related needs, secondary complications, and QoL in adults with SCI. Prior to testing the conceptual model, we aimed to develop and evaluate the factor structure for both SCI-related needs and secondary complications. Individuals with a traumatic SCI (N = 1,137) responded to an online survey measuring 13 SCI-related needs, 13 secondary complications, and the Life Satisfaction Questionnaire to assess QoL. The SCI-related needs and secondary complications were conceptualized into factors, tested with a confirmatory factor analysis, and subsequently evaluated in a structural equation model to predict QoL. The confirmatory factor analysis supported a 2-factor model for SCI related needs, χ(2)(61, N = 1,137) = 250.40, P <.001, comparative fit index (CFI) = .93, root mean square error of approximation (RMSEA) = .05, standardized root mean square residual (SRMR) = .04, and for 11 of the 13 secondary complications, χ(2)(44, N = 1,137) = 305.67, P < .001, CFI = .91, RMSEA = .060, SRMR = .033. The final 2 secondary complications were kept as observed constructs. In the structural model, both vital and personal development unmet SCI-related needs (β = -.22 and -.20, P < .05, respectively) and the neuro-physiological systems factor (β = -.45, P < .05) were negatively related with QoL. Identifying unmet SCI-related needs of individuals with SCI and preventing or managing secondary complications are essential to their QoL.
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Methodology for the development and calibration of the SCI-QOL item banks
Tulsky, David S.; Kisala, Pamela A.; Victorson, David; Choi, Seung W.; Gershon, Richard; Heinemann, Allen W.; Cella, David
2015-01-01
Objective To develop a comprehensive, psychometrically sound, and conceptually grounded patient reported outcomes (PRO) measurement system for individuals with spinal cord injury (SCI). Methods Individual interviews (n = 44) and focus groups (n = 65 individuals with SCI and n = 42 SCI clinicians) were used to select key domains for inclusion and to develop PRO items. Verbatim items from other cutting-edge measurement systems (i.e. PROMIS, Neuro-QOL) were included to facilitate linkage and cross-population comparison. Items were field tested in a large sample of individuals with traumatic SCI (n = 877). Dimensionality was assessed with confirmatory factor analysis. Local item dependence and differential item functioning were assessed, and items were calibrated using the item response theory (IRT) graded response model. Finally, computer adaptive tests (CATs) and short forms were administered in a new sample (n = 245) to assess test-retest reliability and stability. Participants and Procedures A calibration sample of 877 individuals with traumatic SCI across five SCI Model Systems sites and one Department of Veterans Affairs medical center completed SCI-QOL items in interview format. Results We developed 14 unidimensional calibrated item banks and 3 calibrated scales across physical, emotional, and social health domains. When combined with the five Spinal Cord Injury – Functional Index physical function banks, the final SCI-QOL system consists of 22 IRT-calibrated item banks/scales. Item banks may be administered as CATs or short forms. Scales may be administered in a fixed-length format only. Conclusions The SCI-QOL measurement system provides SCI researchers and clinicians with a comprehensive, relevant and psychometrically robust system for measurement of physical-medical, physical-functional, emotional, and social outcomes. All SCI-QOL instruments are freely available on Assessment CenterSM. PMID:26010963
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Methodology for the development and calibration of the SCI-QOL item banks.
Tulsky, David S; Kisala, Pamela A; Victorson, David; Choi, Seung W; Gershon, Richard; Heinemann, Allen W; Cella, David
2015-05-01
To develop a comprehensive, psychometrically sound, and conceptually grounded patient reported outcomes (PRO) measurement system for individuals with spinal cord injury (SCI). Individual interviews (n=44) and focus groups (n=65 individuals with SCI and n=42 SCI clinicians) were used to select key domains for inclusion and to develop PRO items. Verbatim items from other cutting-edge measurement systems (i.e. PROMIS, Neuro-QOL) were included to facilitate linkage and cross-population comparison. Items were field tested in a large sample of individuals with traumatic SCI (n=877). Dimensionality was assessed with confirmatory factor analysis. Local item dependence and differential item functioning were assessed, and items were calibrated using the item response theory (IRT) graded response model. Finally, computer adaptive tests (CATs) and short forms were administered in a new sample (n=245) to assess test-retest reliability and stability. A calibration sample of 877 individuals with traumatic SCI across five SCI Model Systems sites and one Department of Veterans Affairs medical center completed SCI-QOL items in interview format. We developed 14 unidimensional calibrated item banks and 3 calibrated scales across physical, emotional, and social health domains. When combined with the five Spinal Cord Injury--Functional Index physical function banks, the final SCI-QOL system consists of 22 IRT-calibrated item banks/scales. Item banks may be administered as CATs or short forms. Scales may be administered in a fixed-length format only. The SCI-QOL measurement system provides SCI researchers and clinicians with a comprehensive, relevant and psychometrically robust system for measurement of physical-medical, physical-functional, emotional, and social outcomes. All SCI-QOL instruments are freely available on Assessment CenterSM.
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Kadekawa, Katsumi; Majima, Tsuyoshi; Shimizu, Takahiro; Wada, Naoki; de Groat, William C; Kanai, Anthony J; Goto, Momokazu; Yoshiyama, Mitsuharu; Sugaya, Kimio; Yoshimura, Naoki
2017-09-01
We examined bladder and urethral sphincter activity in mice with or without spinal cord injury (SCI) after C-fiber afferent desensitization induced by capsaicin pretreatment and changes in electrophysiological properties of mouse bladder afferent neurons 4 wk after SCI. Female C57BL/6N mice were divided into four groups: 1 ) spinal intact (SI)-control, 2 ) SI-capsaicin pretreatment (Cap), 3 ) SCI-control, and 4 ) SCI-Cap groups. Continuous cystometry and external urethral sphincter (EUS)-electromyogram (EMG) were conducted under an awake condition. In the Cap groups, capsaicin (25, 50, or 100 mg/kg) was injected subcutaneously 4 days before the experiments. In the SI-Cap group, 100 mg/kg capsaicin pretreatment significantly increased bladder capacity and decreased the silent period duration of EUS/EMG compared with the SI-control group. In the SCI-Cap group, 50 and 100 mg/kg capsaicin pretreatment decreased the number of nonvoiding contractions (NVCs) and the duration of reduced EUS activity during voiding, respectively, compared with the SCI-control group. In SCI mice, hexamethonium, a ganglionic blocker, almost completely blocked NVCs, suggesting that they are of neurogenic origin. Patch-clamp recordings in capsaicin-sensitive bladder afferent neurons from SCI mice showed hyperexcitability, which was evidenced by decreased spike thresholds and increased firing rate compared with SI mice. These results indicate that capsaicin-sensitive C-fiber afferent pathways, which become hyperexcitable after SCI, can modulate bladder and urethral sphincter activity in awake SI and SCI mice. Detrusor overactivity as shown by NVCs in SCI mice is significantly but partially dependent on capsaicin-sensitive C-fiber afferents, whereas the EUS relaxation during voiding is enhanced by capsaicin-sensitive C-fiber bladder afferents in SI and SCI mice. Copyright © 2017 the American Physiological Society.
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O'Connor, Gregory; Jeffrey, Elisabeth; Madorma, Derik; Marcillo, Alexander; Abreu, Maria T; Deo, Sapna K; Dietrich, W Dalton; Daunert, Sylvia
2018-06-07
Although there has been a significant amount of research focused on the pathophysiology of spinal cord injury (SCI), there is limited information on the consequences of SCI on remote organs. SCI can produce significant effects on a variety of organ systems, including the gastrointestinal tract. Patients with SCI often suffer from severe, debilitating bowel dysfunction in addition to their physical disabilities, which is of major concern for these individuals because of the adverse impact on their quality of life. Herein, we report on our investigation into the effects of SCI and subsequent antibiotic treatment on the intestinal tissue and microbiota. For that, we used a thoracic SCI rat model and investigated changes to the microbiota, proinflammatory cytokine levels, and bacterial communication molecule levels post-injury and gentamicin treatment for 7 days. We discovered significant changes, the most interesting being the differences in the gut microbiota beta diversity of 8-week SCI animals compared to control animals at the family, genus, and species level. Specifically, 35 operational taxonomic units were enriched in the SCI animal group and three were identified at species level; Lactobacillus intestinalis, Clostridium disporicum, and Bifidobacterium choerinum. In contrast, Clostridium saccharogumia was identified as depleted in the SCI animal group. Proinflammatory cytokines interleukin (IL)-12, macrophage inflammatory protein-2 (MIP-2), and tumor necrosis factor alpha were found to be significantly elevated in intestinal tissue homogenate 4 weeks post-SCI compared to 8-weeks post-injury. Further, levels of IL-1β, IL-12, and MIP-2 significantly correlated with changes in beta diversity 8-weeks post-SCI. Our data provide a greater understanding of the early effects of SCI on the microbiota and gastrointestinal tract, highlighting the need for further investigation to elucidate the mechanism underlying these effects.
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Cameron, Carrie; Lee, Hwa Young; Anderson, Cheryl; Byars-Winston, Angela; Baldwin, Constance D; Chang, Shine
2015-01-01
Scientific communication (SciComm) skills are indispensable for success in biomedical research, but many trainees may not have fully considered the necessity of regular writing and speaking for research career progression. Our purpose was to investigate the relationship between SciComm skill acquisition and research trainees' intentions to remain in research careers. We used social cognitive career theory (SCCT) to test a model of the relationship of SciComm skills to SciComm-related cognitive variables in explaining career intentions. A sample of 510 graduate students and postdoctoral fellows at major academic health science centers in the Texas Medical Center, Houston, Texas, were surveyed online. Results suggested that interest in performing SciComm tasks, SciComm outcome expectations (SCOEs), and SciComm productivity predicted intention to remain in a research career, while SciComm self-efficacy did not directly predict career intention. SCOEs also predicted interest in performing SciComm tasks. As in other SCCT studies, SciComm self-efficacy predicted SCOEs. We conclude that social cognitive factors of SciComm skill acquisition and SciComm productivity significantly predict biomedical trainees' intentions to pursue research careers whether within or outside academia. While further studies are needed, these findings may lead to evidence-based interventions to help trainees remain in their chosen career paths. © 2015 C. Cameron et al. CBE—Life Sciences Education © 2015 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).
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Investigating molecule-semiconductor interfaces with nonlinear spectroscopies
NASA Astrophysics Data System (ADS)
Giokas, Paul George
Knowledge of electronic structures and transport mechanisms at molecule-semiconductor interfaces is motivated by their ubiquity in photoelectrochemical cells. In this dissertation, optical spectroscopies are used uncover the influence of electronic coupling, coherent vibrational motion, and molecular geometry, and other factors on dynamics initiated by light absorption at such interfaces. These are explored for a family of ruthenium bipyridyl chromophores bound to titanium dioxide. Transient absorption measurements show molecular singlet state electron injection in 100 fs or less. Resonance Raman intensity analysis suggests the electronic excitations possess very little charge transfer character. The connections drawn in this work between molecular structure and photophysical behavior contribute to the general understanding of photoelectrochemical cells. Knowledge of binding geometry in nanocrystalline films is challenged by heterogeneity of semiconductor surfaces. Polarized resonance Raman spectroscopy is used to characterize the ruthenium chromophore family on single crystal titanium dioxide . Chromophores display a broad distribution of molecular geometries at the interface, with increased variation in binding angle due to the presence of a methylene bridge, as well as additional phosphonate anchors. This result implies multiple binding configurations for chromophores which incorporate multiple phosphonate ligands, and indicates the need for careful consideration when developing surface-assembled chromophore-catalyst cells. Electron transfer transitions occurring on the 100 fs time scale challenge conventional second-order approximations made when modeling these reactions. A fourth-order perturbative model which includes the relationship between coincident electron transfer and nuclear relaxation processes is presented. Insights provided by the model are illustrated for a two-level donor molecule. The presented fourth-order rate formula constitutes a rigorous and intuitive framework for understanding sub-picosecond photoinduced electron transfer dynamics. Charge transfer systems fit by this model include catechol-sensitized titanium dioxide nanoparticles and a closely-related molecular complex. These systems exhibit vibrational coherence coincident with back-electron transfer in the first picosecond after excitation, which suggests that intramolecular nuclear motion strongly influences the electronic transfer process and plays an important role in the dynamics of interfacial systems following light absorption.
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Scherer, Reinhold; Faller, Josef; Friedrich, Elisabeth V C; Opisso, Eloy; Costa, Ursula; Kübler, Andrea; Müller-Putz, Gernot R
2015-01-01
Brain-computer interfaces (BCIs) translate oscillatory electroencephalogram (EEG) patterns into action. Different mental activities modulate spontaneous EEG rhythms in various ways. Non-stationarity and inherent variability of EEG signals, however, make reliable recognition of modulated EEG patterns challenging. Able-bodied individuals who use a BCI for the first time achieve - on average - binary classification performance of about 75%. Performance in users with central nervous system (CNS) tissue damage is typically lower. User training generally enhances reliability of EEG pattern generation and thus also robustness of pattern recognition. In this study, we investigated the impact of mental tasks on binary classification performance in BCI users with central nervous system (CNS) tissue damage such as persons with stroke or spinal cord injury (SCI). Motor imagery (MI), that is the kinesthetic imagination of movement (e.g. squeezing a rubber ball with the right hand), is the "gold standard" and mainly used to modulate EEG patterns. Based on our recent results in able-bodied users, we hypothesized that pair-wise combination of "brain-teaser" (e.g. mental subtraction and mental word association) and "dynamic imagery" (e.g. hand and feet MI) tasks significantly increases classification performance of induced EEG patterns in the selected end-user group. Within-day (How stable is the classification within a day?) and between-day (How well does a model trained on day one perform on unseen data of day two?) analysis of variability of mental task pair classification in nine individuals confirmed the hypothesis. We found that the use of the classical MI task pair hand vs. feed leads to significantly lower classification accuracy - in average up to 15% less - in most users with stroke or SCI. User-specific selection of task pairs was again essential to enhance performance. We expect that the gained evidence will significantly contribute to make imagery-based BCI technology become accessible to a larger population of users including individuals with special needs due to CNS damage.
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Scherer, Reinhold; Faller, Josef; Friedrich, Elisabeth V. C.; Opisso, Eloy; Costa, Ursula; Kübler, Andrea; Müller-Putz, Gernot R.
2015-01-01
Brain-computer interfaces (BCIs) translate oscillatory electroencephalogram (EEG) patterns into action. Different mental activities modulate spontaneous EEG rhythms in various ways. Non-stationarity and inherent variability of EEG signals, however, make reliable recognition of modulated EEG patterns challenging. Able-bodied individuals who use a BCI for the first time achieve - on average - binary classification performance of about 75%. Performance in users with central nervous system (CNS) tissue damage is typically lower. User training generally enhances reliability of EEG pattern generation and thus also robustness of pattern recognition. In this study, we investigated the impact of mental tasks on binary classification performance in BCI users with central nervous system (CNS) tissue damage such as persons with stroke or spinal cord injury (SCI). Motor imagery (MI), that is the kinesthetic imagination of movement (e.g. squeezing a rubber ball with the right hand), is the "gold standard" and mainly used to modulate EEG patterns. Based on our recent results in able-bodied users, we hypothesized that pair-wise combination of "brain-teaser" (e.g. mental subtraction and mental word association) and "dynamic imagery" (e.g. hand and feet MI) tasks significantly increases classification performance of induced EEG patterns in the selected end-user group. Within-day (How stable is the classification within a day?) and between-day (How well does a model trained on day one perform on unseen data of day two?) analysis of variability of mental task pair classification in nine individuals confirmed the hypothesis. We found that the use of the classical MI task pair hand vs. feed leads to significantly lower classification accuracy - in average up to 15% less - in most users with stroke or SCI. User-specific selection of task pairs was again essential to enhance performance. We expect that the gained evidence will significantly contribute to make imagery-based BCI technology become accessible to a larger population of users including individuals with special needs due to CNS damage. PMID:25992718
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Molecular Simulations of the Diffusion of Uranyl Carbonate Species in Nanosized Mineral Fractures
NASA Astrophysics Data System (ADS)
Kerisit, S.; Liu, C.
2010-12-01
Uranium is a major groundwater contaminant at uranium processing and mining sites as a result of intentional and accidental discharges of uranium-containing waste products into subsurface environments. Recent characterization has shown that uranium preferentially associates with intragrain and intra-aggregate domains in some of the uranium-contaminated sediments collected from the US Department of Energy Hanford Site [1, 2]. In these sediments, uranium existed as precipitated and/or adsorbed phases in grain micropores with nano- to microscale sizes. Desorption and diffusion characterization studies and continuum-scale modeling indicated that ion diffusion in the microfractures is a major mechanism that led to preferential uranium concentration in the microfracture regions and will control the future mobility of uranium in the subsurface sediments [1, 3-4]. However, the diffusion properties of uranyl species in the intragrain regions, especially at the solid-liquid interface, are still poorly understood. Therefore, a general aim of this work is to provide atomic-level insights into the contribution of microscopic surface effects to the slow diffusion process of uranyl species in porous media with nano- to microsized fractures. In this presentation, we will first present molecular dynamics (MD) simulations of feldspar-water interfaces to investigate their interfacial structure and dynamics and establish a theoretical framework for subsequent simulations of water and ion diffusion at these interfaces [5]. We will then report on MD simulations carried out to probe the effects of confinement and of the presence of the mineral surface on the diffusion of water and electrolyte ions in nanosized feldspar fractures [6]. Several properties of the mineral-water interface were varied, such as the fracture width, the ionic strength of the contacting solution, and the surface charge. Our calculations reveal a 2.0-2.5 nm interfacial region within which the diffusion properties of water and that of the electrolyte ions differ significantly from those in bulk aqueous solutions. We will then present MD simulations of the diffusion of a series of alkaline-earth uranyl carbonate species in aqueous solutions [7]. The MD simulations show that the alkaline-earth uranyl carbonate complexes have distinct water exchange dynamics, which could lead to different reactivities. Finally, we will present recent results on the diffusion and adsorption of uranyl carbonate species in intragrain micropores, modeled with the feldspar-water interfaces mentioned in the above, to help interpret the diffusion behavior of uranium in contaminated sediments. [1] Liu C. et al. Geochim. Cosmochim. Acta 68 4519 (2004) [2] McKinley J. P. et al. Geochim. Cosmochim. Acta 70 1873 (2006) [3] Liu C. et al. Water Resour. Res. 42 W12420 (2006) [4] Ilton E. S. et al. Environ. Sci. Technol. 42 1565 (2009) [5] Kerisit S. et al. Geochim. Cosmochim. Acta 72 1481 (2008) [6] Kerisit S. and Liu C. Environ. Sci. Technol. 43 777 (2009) [7] Kerisit S. and Liu C. Geochim. Cosmochim. Acta 74 4937 (2010)
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Druschel, Claudia; Schaser, Klaus-Dieter; Schwab, Jan M
2013-05-15
Written mail-out survey. To determine current practice in high-dose methylprednisolone succinate (MPSS) administration for treatment of acute spinal cord injury (SCI) in Germany. Reanalysis of the National Acute Spinal Cord Injury Studies (NASCIS) resulted in criticism of the use of high-dose MPSS for treatment of acute SCI. Subsequently, SCI treatment guidelines were revised leading to a reduction in MPSS use across North America. The impact of these revisions on SCI treatment in Germany is not known. A questionnaire was sent to all trauma, orthopedic and neurosurgical departments of German university centers, affiliated teaching hospitals, and specialized SCI care centers. Survey included 6 questions about the administration of MPSS after acute SCI. Three hundred seventy-two respondents completed the survey (response rate: 51% overall, 76% university hospitals, 85% specialized SCI care centers). Overall, 55% of departments that treat SCI prescribe MPSS. Among them, 73% are "frequent" users administering MPSS to more than 50% of their patients. Ten percent prescribe according to NASCIS I, 43% NASCIS II, 33% NASCIS III, and 13% "generic protocols." As justification for MPSS treatment, "effectiveness" ranked before "common practice" and "medicolegal reasons." "Specialized" SCI care centers differ in that (1) MPSS is administered less frequently, (2) NASCIS I doses are not used, and (3) during the past several years, practice patterns are more likely to have shifted away from the treatment of SCI with MPSS. About one-half of the institutions continue to prescribe MPSS in the setting of acute SCI. A need for further education in almost one-fourth of German departments treating acute SCI is demonstrated through responses indicating use of the outdated NASCIS I protocol, a "legal need" or "unchanged MPSS application during the last years." "Specialized" SCI centers are more likely to change their practice in accordance with evolving literature. 3.
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Persistent Polyuria in a Rat Spinal Contusion Model
Ward, Patricia J.
2012-01-01
Abstract Polyuria contributes to bladder overdistention, which confounds both lower and upper urinary tract management in individuals having a spinal cord injury (SCI). Bladder overdistention post-SCI is one of the most common triggers for autonomic dysreflexia, a potentially life-threatening condition. Post-SCI polyuria is thought to result from loss of vascular tone in the lower extremities, leading to edema and subsequent excess fluid, resulting in polyuria. Mild SCIs that have near complete recovery would therefore be expected to have little to no polyuria, while severe injuries resulting in flaccid limbs and lower extremity edema would be expected to exhibit severe polyuria. Since interventions that may decrease lower extremity edema are recommended to lessen the severity of polyuria, step training (which promotes vascular circulation) was evaluated as a therapy to reduce post-SCI polyuria. In the present study, polyuria was evaluated in mild, moderate, and severe contusive SCI in adult male rats. The animals were housed in metabolic cages for 24-hour periods pre- and post-SCI (to 6 weeks). Urine, feces, food, water, and body weights were collected. Other assessments included residual expressed urine volumes, locomotor scoring, in-cage activity, and lesion histology. SCI produced an immediate increase in 24-hour urine collection, as early as 3 days post-SCI. Approximately 2.6-fold increases in urine collection occurred from weeks 1–6 post-SCI for all injury severities. Even with substantial gains in locomotor and bladder function following a mild SCI, polyuria remained severe. Step training (30 min/day, 6 days/week) did not alleviate polyuria in the moderate SCI contusion group. These results indicate that (1) mild injuries retaining weight-bearing locomotion that should have mild, if any, edema/loss of vascular tone still exhibit severe polyuria, and (2) step training was unable to reduce post-SCI polyuria. Taken together, these results indicate that the current mechanistic hypothesis of post-SCI polyuria may be incomplete. PMID:22708983
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Persistent polyuria in a rat spinal contusion model.
Ward, Patricia J; Hubscher, Charles H
2012-10-10
Polyuria contributes to bladder overdistention, which confounds both lower and upper urinary tract management in individuals having a spinal cord injury (SCI). Bladder overdistention post-SCI is one of the most common triggers for autonomic dysreflexia, a potentially life-threatening condition. Post-SCI polyuria is thought to result from loss of vascular tone in the lower extremities, leading to edema and subsequent excess fluid, resulting in polyuria. Mild SCIs that have near complete recovery would therefore be expected to have little to no polyuria, while severe injuries resulting in flaccid limbs and lower extremity edema would be expected to exhibit severe polyuria. Since interventions that may decrease lower extremity edema are recommended to lessen the severity of polyuria, step training (which promotes vascular circulation) was evaluated as a therapy to reduce post-SCI polyuria. In the present study, polyuria was evaluated in mild, moderate, and severe contusive SCI in adult male rats. The animals were housed in metabolic cages for 24-hour periods pre- and post-SCI (to 6 weeks). Urine, feces, food, water, and body weights were collected. Other assessments included residual expressed urine volumes, locomotor scoring, in-cage activity, and lesion histology. SCI produced an immediate increase in 24-hour urine collection, as early as 3 days post-SCI. Approximately 2.6-fold increases in urine collection occurred from weeks 1-6 post-SCI for all injury severities. Even with substantial gains in locomotor and bladder function following a mild SCI, polyuria remained severe. Step training (30 min/day, 6 days/week) did not alleviate polyuria in the moderate SCI contusion group. These results indicate that (1) mild injuries retaining weight-bearing locomotion that should have mild, if any, edema/loss of vascular tone still exhibit severe polyuria, and (2) step training was unable to reduce post-SCI polyuria. Taken together, these results indicate that the current mechanistic hypothesis of post-SCI polyuria may be incomplete.
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E2F4 Promotes Neuronal Regeneration and Functional Recovery after Spinal Cord Injury in Zebrafish
Sasagawa, Shota; Nishimura, Yuhei; Hayakawa, Yuka; Murakami, Soichiro; Ashikawa, Yoshifumi; Yuge, Mizuki; Okabe, Shiko; Kawaguchi, Koki; Kawase, Reiko; Tanaka, Toshio
2016-01-01
Mammals exhibit poor recovery after spinal cord injury (SCI), whereas non-mammalian vertebrates exhibit significant spontaneous recovery after SCI. The mechanisms underlying this difference have not been fully elucidated; therefore, the purpose of this study was to investigate these mechanisms. Using comparative transcriptome analysis, we demonstrated that genes related to cell cycle were significantly enriched in the genes specifically dysregulated in zebrafish SCI. Most of the cell cycle-related genes dysregulated in zebrafish SCI were down-regulated, possibly through activation of e2f4. Using a larval zebrafish model of SCI, we demonstrated that the recovery of locomotive function and neuronal regeneration after SCI were significantly inhibited in zebrafish treated with an E2F4 inhibitor. These results suggest that activation of e2f4 after SCI may be responsible, at least in part, for the significant recovery in zebrafish. This provides novel insight into the lack of recovery after SCI in mammals and informs potential therapeutic strategies. PMID:27242526
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Collapse of superconductivity in cuprates via ultrafast quenching of phase coherence
Boschini, F.; da Silva Neto, E. H.; Razzoli, E.; ...
2018-04-02
The possibility of driving phase transitions in low-density condensates through the loss of phase coherence alone has far-reaching implications for the study of quantum phases of matter. This has inspired the development of tools to control and explore the collective properties of condensate phases via phase fluctuations. Electrically gated oxide interfaces, ultracold Fermi atoms and cuprate superconductors, which are characterized by an intrinsically small phase stiffness, are paradigmatic examples where these tools are having a dramatic impact. In this study, we use light pulses shorter than the internal thermalization time to drive and probe the phase fragility of the Bimore » 2Sr 2CaCu 2O 8+δ cuprate superconductor, completely melting the superconducting condensate without affecting the pairing strength. The resulting ultrafast dynamics of phase fluctuations and charge excitations are captured and disentangled by time-resolved photoemission spectroscopy. This work demonstrates the dominant role of phase coherence in the superconductor-to-normal state phase transition and offers a benchmark for non-equilibrium spectroscopic investigations of the cuprate phase diagram.« less
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NASA Astrophysics Data System (ADS)
Yang, Xue; Brunetti, Enrico; Jaroszynski, Dino A.
2018-04-01
High-charge electron beams produced by laser-wakefield accelerators are potentially novel, scalable sources of high-power terahertz radiation suitable for applications requiring high-intensity fields. When an intense laser pulse propagates in underdense plasma, it can generate femtosecond duration, self-injected picocoulomb electron bunches that accelerate on-axis to energies from 10s of MeV to several GeV, depending on laser intensity and plasma density. The process leading to the formation of the accelerating structure also generates non-injected, sub-picosecond duration, 1–2 MeV nanocoulomb electron beams emitted obliquely into a hollow cone around the laser propagation axis. These wide-angle beams are stable and depend weakly on laser and plasma parameters. Here we perform simulations to characterise the coherent transition radiation emitted by these beams if passed through a thin metal foil, or directly at the plasma–vacuum interface, showing that coherent terahertz radiation with 10s μJ to mJ-level energy can be produced with an optical to terahertz conversion efficiency up to 10‑4–10‑3.
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Collapse of superconductivity in cuprates via ultrafast quenching of phase coherence
NASA Astrophysics Data System (ADS)
Boschini, F.; da Silva Neto, E. H.; Razzoli, E.; Zonno, M.; Peli, S.; Day, R. P.; Michiardi, M.; Schneider, M.; Zwartsenberg, B.; Nigge, P.; Zhong, R. D.; Schneeloch, J.; Gu, G. D.; Zhdanovich, S.; Mills, A. K.; Levy, G.; Jones, D. J.; Giannetti, C.; Damascelli, A.
2018-05-01
The possibility of driving phase transitions in low-density condensates through the loss of phase coherence alone has far-reaching implications for the study of quantum phases of matter. This has inspired the development of tools to control and explore the collective properties of condensate phases via phase fluctuations. Electrically gated oxide interfaces1,2, ultracold Fermi atoms3,4 and cuprate superconductors5,6, which are characterized by an intrinsically small phase stiffness, are paradigmatic examples where these tools are having a dramatic impact. Here we use light pulses shorter than the internal thermalization time to drive and probe the phase fragility of the Bi2Sr2CaCu2O8+δ cuprate superconductor, completely melting the superconducting condensate without affecting the pairing strength. The resulting ultrafast dynamics of phase fluctuations and charge excitations are captured and disentangled by time-resolved photoemission spectroscopy. This work demonstrates the dominant role of phase coherence in the superconductor-to-normal state phase transition and offers a benchmark for non-equilibrium spectroscopic investigations of the cuprate phase diagram.
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Kinetic mechanism of V-shaped twinning in 3C/4H-SiC heteroepitaxy
DOE Office of Scientific and Technical Information (OSTI.GOV)
Xin, Bin; Zhang, Yu-Ming; Jia, Ren-Xu, E-mail: rxjia@mail.xidian.edu.cn
The authors investigated the kinetic mechanism of V-shaped twinning in 3C/4H-SiC heteroepitaxy. A fourfold V-shaped twinning complex was found, and its interface was measured with high-resolution transmission electron microscopy (HRTEM). Two linear coherent boundaries and a nonlinear incoherent boundary (also called the double-position boundary) were observed. On the basis of the HRTEM results, the authors proposed an adatom migration growth model, in which the activation barrier at the coherent boundary is much lower than that at the incoherent boundary. From a kinetic perspective, adatoms are prone to migrate to the side of the boundary with the lower potential energy ifmore » they have sufficient thermal energy to overcome the activation barrier. In the case of a coherent boundary, the growth rates of the domains either side of the boundary can be balanced through the intermigration of adatoms, leading to a linear boundary. Conversely, it is difficult for adatoms to migrate across an incoherent boundary, which results in asynchronous growth rates and a nonlinear boundary.« less
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Collapse of superconductivity in cuprates via ultrafast quenching of phase coherence
DOE Office of Scientific and Technical Information (OSTI.GOV)
Boschini, F.; da Silva Neto, E. H.; Razzoli, E.
The possibility of driving phase transitions in low-density condensates through the loss of phase coherence alone has far-reaching implications for the study of quantum phases of matter. This has inspired the development of tools to control and explore the collective properties of condensate phases via phase fluctuations. Electrically gated oxide interfaces, ultracold Fermi atoms and cuprate superconductors, which are characterized by an intrinsically small phase stiffness, are paradigmatic examples where these tools are having a dramatic impact. In this study, we use light pulses shorter than the internal thermalization time to drive and probe the phase fragility of the Bimore » 2Sr 2CaCu 2O 8+δ cuprate superconductor, completely melting the superconducting condensate without affecting the pairing strength. The resulting ultrafast dynamics of phase fluctuations and charge excitations are captured and disentangled by time-resolved photoemission spectroscopy. This work demonstrates the dominant role of phase coherence in the superconductor-to-normal state phase transition and offers a benchmark for non-equilibrium spectroscopic investigations of the cuprate phase diagram.« less
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Mahmoud, Husam; Qannam, Hazem; Mortenson, Ben
2017-01-01
Objectives 1) To describe functional status, length of stay (LOS), and time to rehabilitation admission trends. 2) To identify independent predictors of motor function following rehabilitation for traumatic and nontraumatic spinal cord injury (SCI). Participants Adult patients with SCI discharged from inpatient rehabilitation between 2009–2014. Design Retrospective cohort study. Setting Spinal injury rehabilitation unit at the King Fahad Medical City, Riyadh, Saudi Arabia. Methods From retrospective chart reviews of 312 traumatic and 106 nontraumatic SCI, we extracted information on time from injury to rehabilitation admission, rehabilitation LOS, and Functional Independence Measure (FIM) score (admission and discharge). Additionally we collected information on SCI patients’ demographics and injury characteristics. Hierarchical regression was employed to investigate variables associated with FIM motor score at discharge for traumatic SCI and nontraumatic SCI. Outcome measures FIM motor score measured at discharge. Results Mean and median days from injury to rehabilitation admission were not significantly different for traumatic SCI (377±855, 150) and nontraumatic SCI (288±403, 176). Mean and median days for rehabilitation LOS were significantly longer for traumatic SCI (85±60, 70) compared to nontraumatic SCI (64±59, 49) (p=…..). FIM scores improved significantly from admission to discharge in both groups. For individuals with traumatic SCI, after accounting for admission FIM motor score, tetraplegia and time from injury to rehabilitation, admission had a significant but small negative association with discharge FIM motor score. For individuals with nontraumatic SCI, increasing age and AIS score of A or B had a significant negative association with discharge FIM motor score. LOS in rehabilitation was not a significant contributor for either model. Conclusions Decreasing the time from injury to rehabilitation admission may improve outcomes for those with traumatic SCI. Since time spent in rehabilitation was shorter than most other countries, a change in practice in this area may be warranted. Developing new strategies to improve outcomes for older patients with nontraumatic SCI would also be beneficial. PMID:28139661
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Hogan, Timothy P; Hill, Jennifer N; Locatelli, Sara M; Weaver, Frances M; Thomas, Florian P; Nazi, Kim M; Goldstein, Barry; Smith, Bridget M
2016-02-01
Access to health information is crucial to persons living with a spinal cord injury or disorder (SCI/D). Although previous research has provided insights on computer and Internet use among persons with SCI/D, as well as how and where persons with SCI/D gather health information, few studies have focused on U.S. veterans with SCI/D. To characterize health information seeking among veterans with SCI/D and to examine the association between technology use and the characteristics of veterans with SCI/D. Cross-sectional. Veterans Health Administration (VHA). Sample of 290 veterans with SCI/D who utilize services at 2 VHA SCI/D Centers. Postal mail survey. Extent of computer, Internet, and text messaging use, information source use, and e-Health literacy rates. The survey response rate was 38%. The majority of respondents were male (97.2%), younger than 65 years (71.0%), and white (71.7%). Of the respondents, 64.8% indicated that they use a computer, 62.9% reported use of the Internet, and 26.2% reported use of text messaging. The mean overall e-Health Literacy Scale score was 27.3 (standard deviation = 7.2). Similar to findings reported in studies focused outside the veteran population, the most frequent source that veterans turned to for information about SCI/D was a health professional (85.1%); this was also the most frequent source that veterans indicated they would turn to first to get information about SCI/D (75.9%). Other frequently reported sources of information included other persons with SCI/D (41.0%), Internet resources (31.0%), and family and friends (27.9%). Fairly high levels of computer and Internet use exist among veterans with SCI/D. Veterans with SCI/D also have a strong preference for people-particularly health professionals, and to a lesser extent peers and family and friends-as sources of information about SCI/D. These findings highlight the importance of combining technology and human interaction to meet the information needs of this population. Published by Elsevier Inc.
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Lisk, Kristina; Agur, Anne M R; Woods, Nicole N
2017-12-01
Several studies have shown that cognitive integration of basic and clinical sciences supports diagnostic reasoning in novices; however, there has been limited exploration of the ways in which educators can translate this model of mental activity into sound instructional strategies. The use of self-explanation during learning has the potential to promote and support the development of integrated knowledge by encouraging novices to elaborate on the causal relationship between clinical features and basic science mechanisms. To explore the effect of this strategy, we compared diagnostic efficacy of teaching students (n = 71) the clinical features of four musculoskeletal pathologies using either (1) integrated causal basic science descriptions (BaSci group); (2) integrated causal basic science descriptions combined with self-explanation prompts (SE group); (3) basic science mechanisms segregated from the clinical features (SG group). All participants completed a diagnostic accuracy test immediately after learning and 1-week later. The results showed that the BaSci group performed significantly better compared to the SE (p = 0.019) and SG groups (p = 0.004); however, no difference was observed between the SE and SG groups (p = 0.91). We hypothesize that the structure of the self-explanation task may not have supported the development of a holistic conceptual understanding of each disease. These findings suggest that integration strategies need to be carefully structured and applied in ways that support the holistic story created by integrated basic science instruction in order to foster conceptual coherence and to capitalize on the benefits of cognition integration.
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Assessing repository technology. Where do we go from here?
NASA Technical Reports Server (NTRS)
Eichmann, David
1992-01-01
Three sample information retrieval systems, archie, autoLib, and Wide Area Information Service (WAIS), are compared with regard to their expressiveness and usefulness, first in the general context of information retrieval, and then as prospective software reuse repositories. While the representational capabilities of these systems are limited, they provide a useful foundation for future repository efforts, particularly from the perspective of repository distribution and coherent user interface design.
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Assessing repository technology: Where do we go from here?
NASA Technical Reports Server (NTRS)
Eichmann, David A.
1992-01-01
Three sample information retrieval systems, archie, autoLib, and Wide Area Information Service (WAIS), are compared with regard to their expressiveness and usefulness, first in the general context of information retrieval, and then as perspective software reuse repositories. While the representational capabilities of these systems are limited, they provide a useful foundation for future repository efforts, particularly from the perspective of repository distribution and coherent user interface design.
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Coherent quantum transport in hybrid Nb-InGaAs-Nb Josephson junctions
NASA Astrophysics Data System (ADS)
Delfanazari, Kaveh; Puddy, R.; Ma, P.; Cao, M.; Yi, T.; Gul, Y.; Farrer, I.; Ritchie, D.; Joyce, H.; Kelly, M.; Smith, C.
Because of the recently reported detection of Majorana fermions states at the superconductor-semiconductor (S-Sm) interface in InAs nanowire devices, the study of hybrid structures has received renewed interest. In this paper we present experimental results on proximity induced superconductivity in a high-mobility two-dimensional electron gas in InGaAs heterostructures. Eight symmetric S-Sm-S Josephson junctions were fabricated on a single InGaAs chip and each junction was measured individually using a lock-in measurement technique. The superconducting electrodes were made of Niobium (Nb). The measurements were carried out in a dilution fridge with a base temperature of 40 mK, and the quantum transport of junctions were measured below 800 mK. Owing to Andreev reflections at the S-Sm interfaces, the differential resistance (dV/dI) versus V curve shows the well-known subharmonic energy gap structure (SGS) at V = 2ΔNb/ne. The SGS features suppressed significantly with increasing temperature and magnetic field, leading to a shift of the SGSs toward zero bias. Our result paves the way for development of highly transparent hybrid S-Sm-S junctions and coherent circuits for quantum devices capable of performing quantum logic and processing functions.
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RETRACTED ARTICLE: Precipitation behavior of B2-ordered aluminide
NASA Astrophysics Data System (ADS)
Han, Chang-Suk
2006-12-01
Fine dispersion of disordered phases is obtained in Ni-Al-Cr and Fe-Al-Co temary systems. A transmission electron microscope investigation has been performed on the precipitation of α-Cr in B2-ordered β-NiAl with different stoichiometry and α-Fe in B2-FeAl(Co) compound. Precipitation behavior and hardening were investigated by measuring the hardness variation. The hardness of NiAl and FeAl increases appreciably with the fine precipitation of α-Cr and α-Fe, and over-age softening occurs after prolonged aging. In the case of B2-NiAl(Cr), perfect lattice coherency is maintained at the interfaces between the α-Cr particles and the matrix during the initial stage of aging. After prolonged aging, a loss of coherency occurs by the attraction of matrix dislocations to the particle/matrix interface, followed by climbing around the particles. On the other hand, in the case of B2-FeAl(Co), the disordered α-Fe phase is present as a precipitate in the B2-FeAl(Co) matrix and has a cubic-cubic orientation with the matrix. At the early aging periods, prismatic dislocation loops formed in the B2-FeAl(Co) matrix. B2-FeAl(Co) matrix is typically hardened by the precipitation of α-Fe.
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Tunable ion-photon entanglement in an optical cavity.
Stute, A; Casabone, B; Schindler, P; Monz, T; Schmidt, P O; Brandstätter, B; Northup, T E; Blatt, R
2012-05-23
Proposed quantum networks require both a quantum interface between light and matter and the coherent control of quantum states. A quantum interface can be realized by entangling the state of a single photon with the state of an atomic or solid-state quantum memory, as demonstrated in recent experiments with trapped ions, neutral atoms, atomic ensembles and nitrogen-vacancy spins. The entangling interaction couples an initial quantum memory state to two possible light-matter states, and the atomic level structure of the memory determines the available coupling paths. In previous work, the transition parameters of these paths determined the phase and amplitude of the final entangled state, unless the memory was initially prepared in a superposition state (a step that requires coherent control). Here we report fully tunable entanglement between a single (40)Ca(+) ion and the polarization state of a single photon within an optical resonator. Our method, based on a bichromatic, cavity-mediated Raman transition, allows us to select two coupling paths and adjust their relative phase and amplitude. The cavity setting enables intrinsically deterministic, high-fidelity generation of any two-qubit entangled state. This approach is applicable to a broad range of candidate systems and thus is a promising method for distributing information within quantum networks.
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Integration of the Chinese HPC Grid in ATLAS Distributed Computing
NASA Astrophysics Data System (ADS)
Filipčič, A.;
ATLAS Collaboration 2017-10-01
Fifteen Chinese High-Performance Computing sites, many of them on the TOP500 list of most powerful supercomputers, are integrated into a common infrastructure providing coherent access to a user through an interface based on a RESTful interface called SCEAPI. These resources have been integrated into the ATLAS Grid production system using a bridge between ATLAS and SCEAPI which translates the authorization and job submission protocols between the two environments. The ARC Computing Element (ARC-CE) forms the bridge using an extended batch system interface to allow job submission to SCEAPI. The ARC-CE was setup at the Institute for High Energy Physics, Beijing, in order to be as close as possible to the SCEAPI front-end interface at the Computing Network Information Center, also in Beijing. This paper describes the technical details of the integration between ARC-CE and SCEAPI and presents results so far with two supercomputer centers, Tianhe-IA and ERA. These two centers have been the pilots for ATLAS Monte Carlo Simulation in SCEAPI and have been providing CPU power since fall 2015.
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Time domain optical coherence tomography investigation of bone matrix interface in rat femurs
NASA Astrophysics Data System (ADS)
Rusu, Laura-Cristina; Negruá¹±iu, Meda-Lavinia; Sinescu, Cosmin; Hoinoiu, Bogdan; Topala, Florin-Ionel; Duma, Virgil-Florin; Rominu, Mihai; Podoleanu, Adrian G.
2013-08-01
The materials used to fabricate scaffolds for tissue engineering are derived from synthetic polymers, mainly from the polyester family, or from natural materials (e.g., collagen and chitosan). The mechanical properties and the structural properties of these materials can be tailored by adjusting the molecular weight, the crystalline state, and the ratio of monomers in the copolymers. Quality control and adjustment of the scaffold manufacturing process are essential to achieve high standard scaffolds. Most scaffolds are made from highly crystalline polymers, which inevitably result in their opaque appearance. Their 3-D opaque structure prevents the observation of internal uneven surface structures of the scaffolds under normal optical instruments, such as the traditional light microscope. The inability to easily monitor the inner structure of scaffolds as well as the interface with the old bone poses a major challenge for tissue engineering: it impedes the precise control and adjustment of the parameters that affect the cell growth in response to various mimicked culture conditions. The aim of this paper is to investigate the interface between the femur rat bone and the new bone that is obtained using a method of tissue engineering that is based on different artificial matrixes inserted in previously artificially induced defects. For this study, 15 rats were used in conformity with ethical procedures. In all the femurs a round defect was induced by drilling with a 1 mm spherical Co-Cr surgical drill. The matrixes used were Bioss and 4bone. These materials were inserted into the induced defects. The femurs were investigated at 1 week, 1 month, 2 month and three month after the surgical procedures. The interfaces were examined using Time Domain (TD) Optical Coherence Tomography (OCT) combined with Confocal Microscopy (CM). The optical configuration uses two single mode directional couplers with a superluminiscent diode as the source centered at 1300 nm. The scanning procedure is similar to that used in any CM, where the fast scanning is en-face (line rate) and the scanning in depth is much slower (at the frame rate). The results showed open interfaces due to the insufficient healing process, as well as closed interfaces due to a new bone formation inside the defect. The conclusion of this study is that TD-OCT can act as a valuable tool in the investigation of the interface between the old bone and the one that has been newly induced due to the osteoinductive process.
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76 FR 10395 - BreconRidge Manufacturing Solutions, Now Known as Sanmina-SCI Corporation, Division...
Federal Register 2010, 2011, 2012, 2013, 2014
2011-02-24
... Solutions, Now Known as Sanmina-SCI Corporation, Division Optoelectronic and Microelectronic Design and Manufacturing, a Subsidiary of Sanmina-SCI Corporation, Including On- Site Leased Workers From Kelly Services... Manufacturing Solutions, now known as Sanmina-SCI Corporation, Division Optoelectronic and Microelectronic...
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Thomason, Susan S; Graves, Barbara Ann; Madaris, Linda
2014-12-01
The Spinal Cord Impairment Pressure Ulcer Monitoring Tool (SCI-PUMT) was designed to assess pressure ulcer (PrU) healing in the spinal cord impaired (SCI) population. The tool contains 7 variables: wound surface area, depth, edges, tunneling, undermining, exudate type, and necrotic tissue amount. A 2-phased, quantitative pilot study based on the Theory of Reasoned Action and Theory of Planned Behavior was conducted at a large SCI/Disorders Center in the Department of Veterans Affairs (VA). In the first phase of the study, a convenience sample of 5 physicians, 3 advanced practice registered nurses, and 3 certified wound care nurses (CWCN) was surveyed using a 2-part questionnaire to assess use of the SCI-PUMT instrument, its anticipated improvement in PrU assessment, and intent to use the SCI-PUMT in clinical practice. Attitudes, subjective norms, perceived behavioral controls, and barriers related to the intent to use the SCI-PUMT were evaluated using a 5-point Likert scale (range: 1= extremely likely, 5 = extremely unlikely). In the second phase of the study, the electronic health records (EHR) of 24 veterans (with 30 PrUs) who had at least 2 completed SCI-PUMT scores during a 4-week period were used to evaluate whether an association existed between magnitudes of change of total SCI-PUMT scores and ordered changes in PrU treatment. The overall mean score for intent to use SCI-PUMT was 1.80 (SD 0.75). The least favorable scores were for convenience and motivation to use the SCI-PUMT. Analysis of EHR data showed no significant difference in magnitudes of change in the SCI-PUMT score and changes in PrU treatment recommendations made by the CWCNs. The significance was not affected regardless of an increase or no change in the score (χ2 with 1 degree of freedom = 1.158, P = 0.282) or for a decrease in the score (χ2 with 1 degree of freedom = 0.5, P = 0.478). In this pilot study, the expressed intent to use the SCI-PUMT in making clinical decisions was generally positive but reservations remain. Additional research is being conducted to determine the barriers and facilitators to SCI-PUMT implementation. The SCI-PUMT was the first tool found to be valid, reliable, and sensitive to assess PrU healing in persons with SCI, and studies to examine the prospective validity of using this instrument on ulcer treatment decisions and outcomes are warranted.
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NASA Astrophysics Data System (ADS)
Zhao, Qiangli; Wang, Weina; Liu, Fengyi; Lü, Jian; Wang, Wenliang
2017-10-01
To better understand the formation mechanism of oligomeric hydroxyalkyl hydroperoxides HOROO(SCI)nH composed of stabilized Criegee intermediate (SCI) as a chain unit, the reactions of SCI with hydroxyalkyl hydroperoxides (HOROOH) and hydroxyalkylperoxy radical (HORO2) as well as HO2 radical were investigated. For the reactions of HORO2 + SCI, two preferred pathways involving a SCI insertion in HOROOH hydroperoxide bond can be found, and the formation of HOROO(SCI)H is the dominant pathway in the reaction of HOCH2(CH3)2COOH + (CH3)2COO. The structures of the HORO2, HOROOH as well as the SCIs play a crucial role in determining the reactivity of the oligomerization. Both the reactions of HORO2 + SCI + HO2 and HOROOH + SCI could be the source of the processors to the formation of secondary organic aerosol (SOA). But from the point of free energy barriers, the formation of HOROO(SCI)H prefers to follow the mechanism involving initiation by the reaction of a HORO2 and a SCI, sequential addition of SCIs, and termination by reaction with the HO2 radical. The rate coefficients show negative temperature dependence and vary in different systems depending on the reactants. The reaction process and constituents of the products can be regulated by temperature and reactants.
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Zhang, Wenyi; Zhu, Zhaojin; Xie, Bin; Yu, Jun
2017-01-01
Background This study aimed to evaluate the therapeutic effects of abdominal manual therapy (AMT) on bowel dysfunction after spinal cord injury (SCI), investigating interstitial cells of Cajal (ICCs) and related c-kit expression. Methods Model rats were divided as SCI and SCI with drug treatment (intragastric mosapride), low-intensity (SCI + LMT; 50 g, 50 times/min), and high-intensity AMT (SCI + HMT; 100 g, 150 times/min). After 14 days of treatment, weight, improved Basso-Beattie-Bresnahan (BBB) locomotor score, and intestinal movement were evaluated. Morphological structure of spinal cord and colon tissues were examined. Immunostaining, RT-PCR, and western blot were used to assess c-kit expression. Results In SCI rats, AMT could not restore BBB, but it significantly increased weight, shortened time to defecation, increased feces amounts, and improved fecal pellet traits and colon histology. AMT improved the number, distribution, and ultrastructure of colonic ICCs, increasing colonic c-kit mRNA and protein levels. Compared with the SCI + Drug and SCI + LMT groups, the SCI + HMT group showed better therapeutic effect in improving intestinal transmission function and promoting c-kit expression. Conclusions AMT is an effective therapy for recovery of intestinal transmission function. It could repair ICCs and increase c-kit expression in colon tissues after SCI, in a frequency-dependent and pressure-dependent manner. PMID:29349063
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von Stein, Richard T.; Silver, Kristopher S.; Soderlund, David M.
2013-01-01
Sodium channel inhibitor (SCI) insecticides were discovered almost four decades ago but have only recently yielded important commercial products (eg., indoxacarb and metaflumizone). SCI insecticides inhibit sodium channel function by binding selectively to slow-inactivated (non-conducting) sodium channel states. Characterization of the action of SCI insecticides on mammalian sodium channels using both biochemical and electrophysiological approaches demonstrates that they bind at or near a drug receptor site, the "local anesthetic (LA) receptor." This mechanism and site of action on sodium channels differentiates SCI insecticides from other insecticidal agents that act on sodium channels. However, SCI insecticides share a common mode of action with drugs currently under investigation as anticonvulsants and treatments for neuropathic pain. In this paper we summarize the development of the SCI insecticide class and the evidence that this structurally diverse group of compounds have a common mode of action on sodium channels. We then review research that has used site-directed mutagenesis and heterologous expression of cloned mammalian sodium channels in Xenopus laevis oocytes to further elucidate the site and mechanism of action of SCI insecticides. The results of these studies provide new insight into the mechanism of action of SCI insecticides on voltage-gated sodium channels, the location of the SCI insecticide receptor, and its relationship to the LA receptor that binds therapeutic SCI agents. PMID:24072940
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Development and psychometric characteristics of the SCI-QOL Pressure Ulcers scale and short form
Kisala, Pamela A.; Tulsky, David S.; Choi, Seung W.; Kirshblum, Steven C.
2015-01-01
Objective To develop a self-reported measure of the subjective impact of pressure ulcers on health-related quality of life (HRQOL) in individuals with spinal cord injury (SCI) as part of the SCI quality of life (SCI-QOL) measurement system. Design Grounded-theory based qualitative item development methods, large-scale item calibration testing, confirmatory factor analysis (CFA), and item response theory-based psychometric analysis. Setting Five SCI Model System centers and one Department of Veterans Affairs medical center in the United States. Participants Adults with traumatic SCI. Main Outcome Measures SCI-QOL Pressure Ulcers scale. Results 189 individuals with traumatic SCI who experienced a pressure ulcer within the past 7 days completed 30 items related to pressure ulcers. CFA confirmed a unidimensional pool of items. IRT analyses were conducted. A constrained Graded Response Model with a constant slope parameter was used to estimate item thresholds for the 12 retained items. Conclusions The 12-item SCI-QOL Pressure Ulcers scale is unique in that it is specifically targeted to individuals with spinal cord injury and at every stage of development has included input from individuals with SCI. Furthermore, use of CFA and IRT methods provide flexibility and precision of measurement. The scale may be administered in its entirety or as a 7-item “short form” and is available for both research and clinical practice. PMID:26010965
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Zarzycki, Piotr; Thomas, Fabien
2006-10-15
The parallel shape of the potentiometric titration curves for montmorillonite suspension is explained using the surface complexation model and taking into account the surface heterogeneity. The homogeneous models give accurate predictions only if they assume unphysically large values of the equilibrium constants for the exchange process occurring on the basal plane. However, the assumption that the basal plane is energetically heterogeneous allows to fit the experimental data (reported by Avena and De Pauli [M. Avena, C.P. De Pauli, J. Colloid Interface Sci. 202 (1998) 195-204]) for reasonable values of exchange equilibrium constant equal to 1.26 (suggested by Fletcher and Sposito [P. Fletcher, G. Sposito, Clay Miner. 24 (1989) 375-391]). Moreover, we observed the typical behavior of point of zero net proton charge (pznpc) as a function of logarithm of the electrolyte concentration (log[C]). We showed that the slope of the linear dependence, pznpc=f(log[C]), is proportional to the number of isomorphic substitutions in the crystal phase, which was also observed in the experimental studies.
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Analysis of metabolomics datasets with high-performance computing and metabolite atlases
Yao, Yushu; Sun, Terence; Wang, Tony; ...
2015-07-20
Even with the widespread use of liquid chromatography mass spectrometry (LC/MS) based metabolomics, there are still a number of challenges facing this promising technique. Many, diverse experimental workflows exist; yet there is a lack of infrastructure and systems for tracking and sharing of information. Here, we describe the Metabolite Atlas framework and interface that provides highly-efficient, web-based access to raw mass spectrometry data in concert with assertions about chemicals detected to help address some of these challenges. This integration, by design, enables experimentalists to explore their raw data, specify and refine features annotations such that they can be leveraged formore » future experiments. Fast queries of the data through the web using SciDB, a parallelized database for high performance computing, make this process operate quickly. Furthermore, by using scripting containers, such as IPython or Jupyter, to analyze the data, scientists can utilize a wide variety of freely available graphing, statistics, and information management resources. In addition, the interfaces facilitate integration with systems biology tools to ultimately link metabolomics data with biological models.« less
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NASA Astrophysics Data System (ADS)
Sasai, Yoshinori; Nagai, Yuya; Itow, Yoshitaka; Matsubara, Yutaka; Sako, Takashi; Lopez, Diego; Itow, Tsukasa; Munakata, Kazuoki; Kato, Chihiro; Kozai, Masayoshi; Miyazaki, Takahiro; Shibata, Shoichi; Oshima, Akitoshi; Kojima, Hiroshi; Tsuchiya, Harufumi; Watanabe, Kyoko; Koi, Tatsumi; Valdés-Galicia, Jose Francisco; González, Luis Xavier; Ortiz, Ernesto; Musalem, Octavio; Hurtado, Alejandro; Garcia, Rocio; Anzorena, Marcos
2014-12-01
We plan to observe solar neutrons at Mt. Sierra Negra (4,600 m above sea level) in Mexico using the SciBar detector. This project is named the SciBar Cosmic Ray Telescope (SciCRT). The main aims of the SciCRT project are to observe solar neutrons to study the mechanism of ion acceleration on the surface of the sun and to monitor the anisotropy of galactic cosmic-ray muons. The SciBar detector, a fully active tracker, is composed of 14,848 scintillator bars, whose dimension is 300 cm × 2.5 cm × 1.3 cm. The structure of the detector enables us to obtain the particle trajectory and its total deposited energy. This information is useful for the energy reconstruction of primary neutrons and particle identification. The total volume of the detector is 3.0 m × 3.0 m × 1.7 m. Since this volume is much larger than the solar neutron telescope (SNT) in Mexico, the detection efficiency of the SciCRT for neutrons is highly enhanced. We performed the calibration of the SciCRT at Instituto Nacional de Astrofisica, Optica y Electronica (INAOE) located at 2,150 m above sea level in Mexico in 2012. We installed the SciCRT at Mt. Sierra Negra in April 2013 and calibrated this detector in May and August 2013. We started continuous observation in March 2014. In this paper, we report the detector performance as a solar neutron telescope and the current status of the SciCRT.
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Spinal Cord Injury Causes Chronic Liver Pathology in Rats
Sauerbeck, Andrew D.; Laws, J. Lukas; Bandaru, Veera V.R.; Popovich, Phillip G.; Haughey, Norman J.
2015-01-01
Abstract Traumatic spinal cord injury (SCI) causes major disruption to peripheral organ innervation and regulation. Relatively little work has investigated these post-SCI systemic changes, however, despite considerable evidence that multiple organ system dysfunction contributes to chronic impairments in health. Because metabolic dysfunction is common after SCI and the liver is a pivotal site for metabolic homeostasis, we sought to determine if liver pathology occurs as a result of SCI in a rat spinal contusion model. Histologic evidence showed excess lipid accumulation in the liver for at least 21 days post-injury after cervical or midthoracic SCI. Lipidomic analysis revealed an acute increase in hepatic ceramides as well as chronically elevated lactosylceramide. Post-SCI hepatic changes also included increased proinflammatory gene expression, including interleukin (IL)-1α, IL-1β, chemokine ligand-2, and tumor necrosis factor-α mRNA. These were coincident with increased CD68+ macrophages in the liver through 21 days post-injury. Serum alanine transaminase, used clinically to detect liver damage, was significantly increased at 21 days post-injury, suggesting that early metabolic and inflammatory damage preceded overt liver pathology. Surprisingly, liver inflammation was even detected after lumbar SCI. Collectively, these results suggest that SCI produces chronic liver injury with symptoms strikingly similar to those of nonalcoholic steatohepatitis (fatty liver disease). These clinically significant hepatic changes after SCI are known to contribute to systemic inflammation, cardiovascular disease, and metabolic syndrome, all of which are more prevalent in persons with SCI. Targeting acute and prolonged hepatic pathology may improve recovery and reduce long-term complications after SCI. PMID:25036371
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Valproic Acid Increases Expression of Neuronal Stem/Progenitor Cell in Spinal Cord Injury
Bang, Woo-Seok; Cho, Dae-Chul; Kim, Hye-Jeong; Sung, Joo-Kyung
2013-01-01
Objective This study investigates the effect of valproic acid (VPA) on expression of neural stem/progenitor cells (NSPCs) in a rat spinal cord injury (SCI) model. Methods Adult male rats (n=24) were randomly and blindly allocated into three groups. Laminectomy at T9 was performed in all three groups. In group 1 (sham), only laminectomy was performed. In group 2 (SCI-VPA), the animals received a dose of 200 mg/kg of VPA. In group 3 (SCI-saline), animals received 1.0 mL of the saline vehicle solution. A modified aneurysm clip with a closing force of 30 grams was applied extradurally around the spinal cord at T9, and then rapidly released with cord compression persisting for 2 minutes. The rats were sacrificed and the spinal cord were collected one week after SCI. Immunohistochemistry (IHC) and western blotting sample were obtained from 5 mm rostral region to the lesion and prepared. We analyzed the nestin immunoreactivity from the white matter of ventral cord and the ependyma of central canal. Nestin and SOX2 were used for markers for NSPCs and analyzed by IHC and western blotting, respectively. Results Nestin and SOX2 were expressed significantly in the SCI groups but not in the sham group. Comparing SCI groups, nestin and SOX2 expression were much stronger in SCI-VPA group than in SCI-saline group. Conclusion Nestin and SOX2 as markers for NSPCs showed increased expression in SCI-VPA group in comparison with SCI-saline group. This result suggests VPA increases expression of spinal NSPCs in SCI. PMID:24044073
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Effect of lycopene on the blood-spinal cord barrier after spinal cord injury in mice.
Zhang, Qian; Wang, Jianbo; Gu, Zhengsong; Zhang, Qing; Zheng, Hong
2016-09-05
The current study aimed to investigate the effect of lycopene on the blood-spinal cord barrier (BSCB) after spinal cord injury (SCI) in a mouse model. Lycopene inhibited lipid peroxidation and oxidative DNA damage as a highly efficient antioxidant and free radical scavenger. Lycopene (4 mg/kg/d) was administrated immediately following SCI. The permeability of the BSCB and water content in the spinal cord tissue were evaluated. Additionally, levels of expression of tight junction proteins and heme oxygenase-1 (HO-1) were determined with Western blotting. An enzyme-linked immunosorbent assay analysis of spinal cord tissue homogenates was performed 48 h after SCI to evaluate the expression of inflammation-related cytokines. In addition, recovery of motor function was assessed 1 d, 2 d, 5 d, 10 d, and 15 d after SCI using the Basso Mouse Scale to score locomotion. Compared to the group with an untreated SCI, mice with an SCI treated with lycopene had significantly reduced spinal cord tissue water content and BSCB permeability. Furthermore, motor function of mice with an SCI was also greatly improved by lycopene administration. The expression of the proinflammatory factors TNF-α and NF-kB increased markedly 48 h after SCI, and their upregulation was significantly attenuated by lycopene treatment. The expression of molecules that protect tight junctions, zonula occluden-1 and claudin-5, was upregulated by lycopene treatment after SCI. Taken together, these results clearly indicate that lycopene attenuated SCI by promoting repair of the damaged BSCB, so lycopene is a novel and promising treatment for SCI in humans.
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GeoSciML v3.0 - a significant upgrade of the CGI-IUGS geoscience data model
NASA Astrophysics Data System (ADS)
Raymond, O.; Duclaux, G.; Boisvert, E.; Cipolloni, C.; Cox, S.; Laxton, J.; Letourneau, F.; Richard, S.; Ritchie, A.; Sen, M.; Serrano, J.-J.; Simons, B.; Vuollo, J.
2012-04-01
GeoSciML version 3.0 (http://www.geosciml.org), released in late 2011, is the latest version of the CGI-IUGS* Interoperability Working Group geoscience data interchange standard. The new version is a significant upgrade and refactoring of GeoSciML v2 which was released in 2008. GeoSciML v3 has already been adopted by several major international interoperability initiatives, including OneGeology, the EU INSPIRE program, and the US Geoscience Information Network, as their standard data exchange format for geoscience data. GeoSciML v3 makes use of recently upgraded versions of several Open Geospatial Consortium (OGC) and ISO data transfer standards, including GML v3.2, SWE Common v2.0, and Observations and Measurements v2 (ISO 19156). The GeoSciML v3 data model has been refactored from a single large application schema with many packages, into a number of smaller, but related, application schema modules with individual namespaces. This refactoring allows the use and future development of modules of GeoSciML (eg; GeologicUnit, GeologicStructure, GeologicAge, Borehole) in smaller, more manageable units. As a result of this refactoring and the integration with new OGC and ISO standards, GeoSciML v3 is not backwardly compatible with previous GeoSciML versions. The scope of GeoSciML has been extended in version 3.0 to include new models for geomorphological data (a Geomorphology application schema), and for geological specimens, geochronological interpretations, and metadata for geochemical and geochronological analyses (a LaboratoryAnalysis-Specimen application schema). In addition, there is better support for borehole data, and the PhysicalProperties model now supports a wider range of petrophysical measurements. The previously used CGI_Value data type has been superseded in favour of externally governed data types provided by OGC's SWE Common v2 and GML v3.2 data standards. The GeoSciML v3 release includes worked examples of best practice in delivering geochemical analytical data using the Observations and Measurements (ISO19156) and SWE Common v2 models. The GeoSciML v3 data model does not include vocabularies to support the data model. However, it does provide a standard pattern to reference controlled vocabulary concepts using HTTP-URIs. The international GeoSciML community has developed distributed RDF-based geoscience vocabularies that can be accessed by GeoSciML web services using the standard pattern recommended in GeoSciML v3. GeoSciML v3 is the first version of GeoSciML that will be accompanied by web service validation tools using Schematron rules. For example, these validation tools may check for compliance of a web service to a particular profile of GeoSciML, or for logical consistency of data content that cannot be enforced by the application schemas. This validation process will support accreditation of GeoSciML services and a higher degree of semantic interoperability. * International Union of Geological Sciences Commission for Management and Application of Geoscience Information (CGI-IUGS)
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Imaging Basin Structure with Teleseismic Virtual Source Reflection Profiles
NASA Astrophysics Data System (ADS)
Yang, Z.; Sheehan, A. F.; Yeck, W. L.; Miller, K. C.; Worthington, L. L.; Erslev, E.; Harder, S. H.; Anderson, M. L.; Siddoway, C. S.
2011-12-01
We demonstrate a case of using teleseisms recorded on single channel high frequency geophones to image upper crustal structure across the Bighorn Arch in north-central Wyoming. The dataset was obtained through the EarthScope FlexArray Bighorn Arch Seismic Experiment (BASE). In addition to traditional active and passive source seismic data acquisition, BASE included a 12 day continuous (passive source) deployment of 850 geophones with 'Texan' dataloggers. The geophones were deployed in three E-W lines in north-central Wyoming extending from the Powder River Basin across the Bighorn Mountains and across the Bighorn Basin, and two N-S lines on east and west flanks of the Bighorn Mountains. The station interval is roughly 1.5-2 km, good for imaging coherent shallow structures. The approach used in this study uses the surface reflection as virtual seismic source and reverberated teleseismic P-wave phase (PpPdp) (teleseismic P-wave reflected at receiver side free surface and then reflected off crustal seismic interface) to construct seismic profiles. These profiles are equivalent to conventional active source seismic reflection profiles except that high-frequency (up to 2.4 Hz) transmitted wave fields from distant earthquakes are used as sources. On the constructed seismic profiles, the coherent PpPdp phases beneath Powder River and Bighorn Basins are distinct after the source wavelet is removed from the seismograms by deconvolution. Under the Bighorn Arch, no clear coherent signals are observed. We combine phases PpPdp and Ps to constrain the averaged Vp/Vs: 2.05-2.15 for the Powder River Basin and 1.9-2.0 for the Bighorn Basin. These high Vp/Vs ratios suggest that the layers within which P-wave reverberates are sedimentary. Assuming Vp as 4 km/s under the Powder River Basin, the estimated thickness of sedimentary layer above reflection below the profile is 3-4.5 km, consistent with the depth of the top of the Tensleep Fm. Therefore we interpret the coherent PpPdp phases about 1-3 s after direct P-wave arrival as the reflections off the interface between the Paleozoic carbonates/sandstones and Mesozoic shales.
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The Secret Life of Quarks, Final Report for the University of North Carolina at Chapel Hill
DOE Office of Scientific and Technical Information (OSTI.GOV)
Fowler, Robert J.
This final report summarizes activities and results at the University of North Carolina as part of the the SciDAC-2 Project The Secret Life of Quarks: National Computational Infrastructure for Lattice Quantum Chromodynamics. The overall objective of the project is to construct the software needed to study quantum chromo- dynamics (QCD), the theory of the strong interactions of subatomic physics, and similar strongly coupled gauge theories anticipated to be of importance in the LHC era. It built upon the successful efforts of the SciDAC-1 project National Computational Infrastructure for Lattice Gauge Theory, in which a QCD Applications Programming Interface (QCD API)more » was developed that enables lat- tice gauge theorists to make effective use of a wide variety of massively parallel computers. In the SciDAC-2 project, optimized versions of the QCD API were being created for the IBM Blue- Gene/L (BG/L) and BlueGene/P (BG/P), the Cray XT3/XT4 and its successors, and clusters based on multi-core processors and Infiniband communications networks. The QCD API is being used to enhance the performance of the major QCD community codes and to create new applications. Software libraries of physics tools have been expanded to contain sharable building blocks for inclusion in application codes, performance analysis and visualization tools, and software for au- tomation of physics work flow. New software tools were designed for managing the large data sets generated in lattice QCD simulations, and for sharing them through the International Lattice Data Grid consortium. As part of the overall project, researchers at UNC were funded through ASCR to work in three general areas. The main thrust has been performance instrumentation and analysis in support of the SciDAC QCD code base as it evolved and as it moved to new computation platforms. In support of the performance activities, performance data was to be collected in a database for the purpose of broader analysis. Third, the UNC work was done at RENCI (Renaissance Computing Institute), which has extensive expertise and facilities for scientific data visualization, so we acted in an ongoing consulting and support role in that area.« less
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A muscle-driven approach to restore stepping with an exoskeleton for individuals with paraplegia.
Chang, Sarah R; Nandor, Mark J; Li, Lu; Kobetic, Rudi; Foglyano, Kevin M; Schnellenberger, John R; Audu, Musa L; Pinault, Gilles; Quinn, Roger D; Triolo, Ronald J
2017-05-30
Functional neuromuscular stimulation, lower limb orthosis, powered lower limb exoskeleton, and hybrid neuroprosthesis (HNP) technologies can restore stepping in individuals with paraplegia due to spinal cord injury (SCI). However, a self-contained muscle-driven controllable exoskeleton approach based on an implanted neural stimulator to restore walking has not been previously demonstrated, which could potentially result in system use outside the laboratory and viable for long term use or clinical testing. In this work, we designed and evaluated an untethered muscle-driven controllable exoskeleton to restore stepping in three individuals with paralysis from SCI. The self-contained HNP combined neural stimulation to activate the paralyzed muscles and generate joint torques for limb movements with a controllable lower limb exoskeleton to stabilize and support the user. An onboard controller processed exoskeleton sensor signals, determined appropriate exoskeletal constraints and stimulation commands for a finite state machine (FSM), and transmitted data over Bluetooth to an off-board computer for real-time monitoring and data recording. The FSM coordinated stimulation and exoskeletal constraints to enable functions, selected with a wireless finger switch user interface, for standing up, standing, stepping, or sitting down. In the stepping function, the FSM used a sensor-based gait event detector to determine transitions between gait phases of double stance, early swing, late swing, and weight acceptance. The HNP restored stepping in three individuals with motor complete paralysis due to SCI. The controller appropriately coordinated stimulation and exoskeletal constraints using the sensor-based FSM for subjects with different stimulation systems. The average range of motion at hip and knee joints during walking were 8.5°-20.8° and 14.0°-43.6°, respectively. Walking speeds varied from 0.03 to 0.06 m/s, and cadences from 10 to 20 steps/min. A self-contained muscle-driven exoskeleton was a feasible intervention to restore stepping in individuals with paraplegia due to SCI. The untethered hybrid system was capable of adjusting to different individuals' needs to appropriately coordinate exoskeletal constraints with muscle activation using a sensor-driven FSM for stepping. Further improvements for out-of-the-laboratory use should include implantation of plantar flexor muscles to improve walking speed and power assist as needed at the hips and knees to maintain walking as muscles fatigue.
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Valley Phase and Voltage Control of Coherent Manipulation in Si Quantum Dots.
Zimmerman, Neil M; Huang, Peihao; Culcer, Dimitrie
2017-07-12
With any roughness at the interface of an indirect-bandgap semiconducting dot, the phase of the valley-orbit coupling can take on a random value. This random value, in double quantum dots, causes a large change in the exchange splitting. We demonstrate a simple analytical method to calculate the phase, and thus the exchange splitting and singlet-triplet qubit frequency, for an arbitrary interface. We then show that, with lateral control of the position of a quantum dot using a gate voltage, the valley-orbit phase can be controlled over a wide range, so that variations in the exchange splitting can be controlled for individual devices. Finally, we suggest experiments to measure the valley phase and the concomitant gate voltage control.
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Pruitt, S D; Wahlgren, D R; Epping-Jordan, J E; Rossi, A L
1998-10-01
To describe the development and initial psychometric properties of a new outcome measure for health behaviors that delay or prevent secondary impairments associated with spinal cord injury (SCI). Persons with SCI were surveyed during routine annual physical evaluations. Veterans Affairs Medical Center Spinal Cord Injury Unit, which specializes in primary care for persons with SCI. Forty-nine persons with SCI, aged 19-73 years, 1-50 years post-SCI. The newly developed Spinal Cord Injury Lifestyle Scale (SCILS). Internal consistency is high (alpha = 0.81). Correlations between clinicians' ratings of participants' health behavior and the new SCILS provide preliminary support for construct validity. The SCILS is a brief, self-report measure of health-related behavior in persons with SCI. It is a promising new outcome measure to evaluate the effectiveness of clinical and educational efforts for health maintenance and prevention of secondary impairments associated with SCI.
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Clinical interpretation of the Spinal Cord Injury Functional Index (SCI-FI).
Fyffe, Denise; Kalpakjian, Claire Z; Slavin, Mary; Kisala, Pamela; Ni, Pengsheng; Kirshblum, Steven C; Tulsky, David S; Jette, Alan M
2016-09-01
To provide validation of functional ability levels for the Spinal Cord Injury - Functional Index (SCI-FI). Cross-sectional. Inpatient rehabilitation hospital and community settings. A sample of 855 individuals with traumatic spinal cord injury enrolled in 6 rehabilitation centers participating in the National Spinal Cord Injury Model Systems Network. Not Applicable. Spinal Cord Injury-Functional Index (SCI-FI). Cluster analyses identified three distinct groups that represent low, mid-range and high SCI-FI functional ability levels. Comparison of clusters on personal and other injury characteristics suggested some significant differences between groups. These results strongly support the use of SCI-FI functional ability levels to document the perceived functional abilities of persons with SCI. Results of the cluster analysis suggest that the SCI-FI functional ability levels capture function by injury characteristics. Clinical implications regarding tracking functional activity trajectories during follow-up visits are discussed.
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Measurement of Bone: Diagnosis of SCI-Induced Osteoporosis and Fracture Risk Prediction
Morse, Leslie R.
2015-01-01
Background: Spinal cord injury (SCI) is associated with a rapid loss of bone mass, resulting in severe osteoporosis and a 5- to 23-fold increase in fracture risk. Despite the seriousness of fractures in SCI, there are multiple barriers to osteoporosis diagnosis and wide variations in treatment practices for SCI-induced osteoporosis. Methods: We review the biological and structural changes that are known to occur in bone after SCI in the context of promoting future research to prevent or reduce risk of fracture in this population. We also review the most commonly used methods for assessing bone after SCI and discuss the strengths, limitations, and clinical applications of each method. Conclusions: Although dual-energy x-ray absorptiometry assessments of bone mineral density may be used clinically to detect changes in bone after SCI, 3-dimensional methods such as quantitative CT analysis are recommended for research applications and are explained in detail. PMID:26689691
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Mehta, S; Guy, S D; Bryce, T N; Craven, B C; Finnerup, N B; Hitzig, S L; Orenczuk, S; Siddall, P J; Widerström-Noga, E; Casalino, A; Côté, I; Harvey, D; Kras-Dupuis, A; Lau, B; Middleton, J W; Moulin, D E; O'Connell, C; Parrent, A G; Potter, P; Short, C; Teasell, R; Townson, A; Truchon, C; Wolfe, D; Bradbury, C L; Loh, E
2016-08-01
Clinical practice guidelines. To develop the first Canadian clinical practice guidelines for screening and diagnosis of neuropathic pain in people with spinal cord injury (SCI). The guidelines are relevant for inpatient and outpatient SCI rehabilitation settings in Canada. The CanPainSCI Working Group reviewed evidence to address clinical questions regarding screening and diagnosis of neuropathic pain after SCI. A consensus process was followed to achieve agreement on recommendations and clinical considerations. Twelve recommendations, based on expert consensus, were developed for the screening and diagnosis of neuropathic pain after SCI. The recommendations address methods for assessment, documentation tools, team member accountability, frequency of screening and considerations for diagnostic investigation. Important clinical considerations accompany each recommendation. The expert Working Group developed recommendations for the screening and diagnosis of neuropathic pain after SCI that should be used to inform practice.
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Measurement of Bone: Diagnosis of SCI-Induced Osteoporosis and Fracture Risk Prediction.
Troy, Karen L; Morse, Leslie R
2015-01-01
Spinal cord injury (SCI) is associated with a rapid loss of bone mass, resulting in severe osteoporosis and a 5- to 23-fold increase in fracture risk. Despite the seriousness of fractures in SCI, there are multiple barriers to osteoporosis diagnosis and wide variations in treatment practices for SCI-induced osteoporosis. We review the biological and structural changes that are known to occur in bone after SCI in the context of promoting future research to prevent or reduce risk of fracture in this population. We also review the most commonly used methods for assessing bone after SCI and discuss the strengths, limitations, and clinical applications of each method. Although dual-energy x-ray absorptiometry assessments of bone mineral density may be used clinically to detect changes in bone after SCI, 3-dimensional methods such as quantitative CT analysis are recommended for research applications and are explained in detail.
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SciLinks Forgot your login? Sign up for FREE access Log In I'm a ... Teacher Student User Name questions and satisfy their curiosity Learn More Sign up for Free Access Sites in the SciLinks program . SciLinks-Targeted, Grade-Specific Web Content for your Books Free web content to extend and expand student
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DoD-Wide Intelligence Career Development Program. General Intelligence Personnel
1988-07-01
Science ASTRONMY /SPACE SCI Ballistics BALLISTCS Cartography CARTOGRY Cartographic Technician CARTOGR TECH Chemistry/Biochemistry CHEMSTRY/BIOCHEMSTRY...ARCHVST ....................... 4-63 E&E ............................ 4-60 ASTRONMY /SPACE SCI ........... 4-69 ECONMCS ....................... 4-75 AUTO...SPACE SCI-see ASTRONMY / OB-NAV ......................... 4-54 SPACE SCI OCEANOGY ..................... 4-70 SPACE SYS-ENGR ................ 4-48 OFC
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Koo, Hoon Jung; Han, Doug Hyun; Park, Sung-Yong
2017-01-01
Objective This study aimed to develop and validate a Structured Clinical Interview for Internet Gaming Disorder (SCI-IGD) in adolescents. Methods First, we generated preliminary items of the SCI-IGD based on the information from the DSM-5 literature reviews and expert consultations. Next, a total of 236 adolescents, from both community and clinical settings, were recruited to evaluate the psychometric properties of the SCI-IGD. Results First, the SCI-IGD was found to be consistent over the time period of about one month. Second, diagnostic concordances between the SCI-IGD and clinician's diagnostic impression were good to excellent. The Likelihood Ratio Positive and the Likelihood Ratio Negative estimates for the diagnosis of SCI-IGD were 10.93 and 0.35, respectively, indicating that SCI-IGD was ‘very useful test’ for identifying the presence of IGD and ‘useful test’ for identifying the absence of IGD. Third, SCI-IGD could identify disordered gamers from non-disordered gamers. Conclusion The implications and limitations of the study are also discussed. PMID:28096871
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Physical Activity Inventory for Patients with Spinal Cord Injury
Butler, Jolene A.; Miller, Terrya; O’Connell, Susan; Jelinek, Christine; Collins, Eileen G.
2010-01-01
Objectives To test the reliability and validity of a physical activity instrument adapted for individuals with spinal cord injuries (SCI), the Physical Activity Instrument-SCI (PAI-SCI). Methods Eligible participants completed the adapted PAI-SCI questionnaire at baseline and 1 week later. At baseline, they were also given an Actical accelerometer to wear on their wrist for 1 week. Results Forty-three male subjects completed the study. There was a moderate relationship between total score on the PAI-SCI and total activity count determined by accelerometry (r = 0.42, P = 0.036). The PAI-SCI was able to differentiate between people with upper and lower level injuries (P = 0.05). Test-retest reliability was supported for the exercise and the general activity/self care subscales and not supported for the light household or the outdoor/gardening subscales. Conclusion The PAI-SCI was able to distinguish between physical activity amongst those with upper level and lower level injuries. More research is needed before the PAI-SCI can be recommended for use in clinical trials. PMID:25190905
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Nikmehr, Banafsheh; Bazrafkan, Mahshid; Hassanzadeh, Gholamreza; Shahverdi, Abdolhossein; Sadighi Gilani, Mohammad Ali; Kiani, Sahar; Mokhtari, Tahmineh; Abolhassani, Farid
2017-11-04
Expression assessment of the inflammasome genes in the acute and the chronic phases of Spinal cord injury (SCI) on adult rat testis and examination of associations between inflammasome complex expression and sperm parameters. In this study, 25 adult male rats were randomly divided into 5 groups. SCI surgery was performed at T10-T11 level of rats' spinal cord in four groups (SCI1, SCI3, SCI7, and SCI56). They were sacrificed after 1day, 3days, 7days and 56 days post SCI, respectively. One group remained intact as control (Co).CASA analysis of sperm parameters and qRT-PCR (ASC and Caspase-1) were made in all cases. Our data showed a severe reduction in sperm count and motility, especially on day 3 and 7. ASC gene expression had a non-significant increase on day 1 and 56 after surgery compared to control group. Caspase-1 expression increased significantly on day 3 post injury versus the control group (P = .009). Moreover, Caspase-1 overexpression, had significant correlations with sperm count (r = -0.555, P = .01) and sperm progressive motility (r = -0.524, P = .02). Inflammasome complex expression increase following SCI induction. This overexpression correlates to low sperm parameters in SCI rats.
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Development and initial evaluation of the SCI-FI/AT
Jette, Alan M.; Slavin, Mary D.; Ni, Pengsheng; Kisala, Pamela A.; Tulsky, David S.; Heinemann, Allen W.; Charlifue, Susie; Tate, Denise G.; Fyffe, Denise; Morse, Leslie; Marino, Ralph; Smith, Ian; Williams, Steve
2015-01-01
Objectives To describe the domain structure and calibration of the Spinal Cord Injury Functional Index for samples using Assistive Technology (SCI-FI/AT) and report the initial psychometric properties of each domain. Design Cross sectional survey followed by computerized adaptive test (CAT) simulations. Setting Inpatient and community settings. Participants A sample of 460 adults with traumatic spinal cord injury (SCI) stratified by level of injury, completeness of injury, and time since injury. Interventions None Main outcome measure SCI-FI/AT Results Confirmatory factor analysis (CFA) and Item response theory (IRT) analyses identified 4 unidimensional SCI-FI/AT domains: Basic Mobility (41 items) Self-care (71 items), Fine Motor Function (35 items), and Ambulation (29 items). High correlations of full item banks with 10-item simulated CATs indicated high accuracy of each CAT in estimating a person's function, and there was high measurement reliability for the simulated CAT scales compared with the full item bank. SCI-FI/AT item difficulties in the domains of Self-care, Fine Motor Function, and Ambulation were less difficult than the same items in the original SCI-FI item banks. Conclusion With the development of the SCI-FI/AT, clinicians and investigators have available multidimensional assessment scales that evaluate function for users of AT to complement the scales available in the original SCI-FI. PMID:26010975
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Walking in water and on land after an incomplete spinal cord injury.
Tamburella, Federica; Scivoletto, Giorgio; Cosentino, Elena; Molinari, Marco
2013-10-01
Although no data are available on the effects of water environment on the gait of subjects with spinal cord injury (SCI), hydrotherapy is used in the rehabilitation protocols of SCI patients. The aim of this study was to characterize gait features of subjects with incomplete SCI walking in water and on land in comparison with healthy controls (CTRLs) to identify the specificity of water environment on influencing gait in SCI subjects. This is a matched case-control study. Kinematic gait parameters and range of motion of joint angles of 15 SCI subjects and 15 CTRLs were analyzed. Compared with gait on land, gait in water of the SCI patients was characterized by speed and stance phase reduction, gait cycle time increment, and invariance of stride length and range of motion values. Comparison with CTRL data remarked that walking in water reduces gait differences between the groups. Furthermore, in water, the SCI subjects presented a reduction in variability of the hip and knee joint angles, whereas in the CTRLs, a larger variability was observed. Gait in water of the SCI subjects is associated with kinematic parameters more similar to those of the CTRLs, particularly regarding speed, stride length, and stance phase, supporting the idea that walking in a water environment may be of rehabilitative significance for SCI subjects.
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Hopkins, Sam; Scorneaux, Bernard; Huang, Zhuhui; Murray, Michael G.; Wring, Stephen; Smitley, Craig; Harris, Richard; Erdmann, Frank; Fischer, Gunter; Ribeill, Yves
2010-01-01
SCY-635 is a novel nonimmunosuppressive cyclosporine-based analog that exhibits potent suppression of hepatitis C virus (HCV) replication in vitro. SCY-635 inhibited the peptidyl prolyl isomerase activity of cyclophilin A at nanomolar concentrations but showed no detectable inhibition of calcineurin phosphatase activity at concentrations up to 2 μM. Metabolic studies indicated that SCY-635 did not induce the major cytochrome P450 enzymes 1A2, 2B6, and 3A4. SCY-635 was a weak inhibitor and a poor substrate for P-glycoprotein. Functional assays with stimulated Jurkat cells and stimulated human peripheral blood mononuclear cells indicated that SCY-635 is a weaker inhibitor of interleukin-2 secretion than cyclosporine. A series of two-drug combination studies was performed in vitro. SCY-635 exhibited synergistic antiviral activity with alpha interferon 2b and additive antiviral activity with ribavirin. SCY-635 was shown to be orally bioavailable in multiple animal species and produced blood and liver concentrations of parent drug that exceeded the 50% effective dose determined in the bicistronic con1b-derived replicon assay. These results suggest that SCY-635 warrants further investigation as a novel therapeutic agent for the treatment of individuals who are chronically infected with HCV. PMID:19933795
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Development and initial evaluation of the SCI-FI/AT.
Jette, Alan M; Slavin, Mary D; Ni, Pengsheng; Kisala, Pamela A; Tulsky, David S; Heinemann, Allen W; Charlifue, Susie; Tate, Denise G; Fyffe, Denise; Morse, Leslie; Marino, Ralph; Smith, Ian; Williams, Steve
2015-05-01
To describe the domain structure and calibration of the Spinal Cord Injury Functional Index for samples using Assistive Technology (SCI-FI/AT) and report the initial psychometric properties of each domain. Cross sectional survey followed by computerized adaptive test (CAT) simulations. Inpatient and community settings. A sample of 460 adults with traumatic spinal cord injury (SCI) stratified by level of injury, completeness of injury, and time since injury. None SCI-FI/AT RESULTS: Confirmatory factor analysis (CFA) and Item response theory (IRT) analyses identified 4 unidimensional SCI-FI/AT domains: Basic Mobility (41 items) Self-care (71 items), Fine Motor Function (35 items), and Ambulation (29 items). High correlations of full item banks with 10-item simulated CATs indicated high accuracy of each CAT in estimating a person's function, and there was high measurement reliability for the simulated CAT scales compared with the full item bank. SCI-FI/AT item difficulties in the domains of Self-care, Fine Motor Function, and Ambulation were less difficult than the same items in the original SCI-FI item banks. With the development of the SCI-FI/AT, clinicians and investigators have available multidimensional assessment scales that evaluate function for users of AT to complement the scales available in the original SCI-FI.
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The Cross-Cultural Societal Response to SCI: Health and Related Systems.
Pacheco, Diana; Gross-Hemmi, Mirja H
2017-02-01
The Learning Health System for Spinal Cord Injury (LHS-SCI) is an initiative aligned with the World Health Organization's (WHO) Global Disability Action Plan. Based on the outcomes of this initiative, countries will be able to shape their health systems to better respond to the needs of persons with SCI. This paper describes and compares the macroeconomic situation and societal response to SCI across 27 countries from all 6 WHO regions that will participate in the LHS-SCI initiative. A concurrent mixed-methods study was conducted to identify key indicators that describe the situation of persons with SCI, the general societal response, the health and rehabilitation system, and the experience for a SCI person after discharge from inpatient rehabilitation. A strong correlation was found between the efficiency of a healthcare system and the amount a country invests in health. Higher availability of resources does not necessarily imply that unrestricted access to the healthcare system is warranted. Variations in the health systems were found for various domains of the health and rehabilitation systems. The evaluation and comparative analysis of the societal response to SCI raise the awareness of the need of more standardized data to identify current needs and gaps in the quality and access to SCI-specific health system.
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Meng, Fan Xing; Hou, Jing Ming; Sun, Tian Sheng
2017-02-08
Central pain (CP) is a common clinical problem in patients with spinal cord injury (SCI). Recent studies found the pathogenesis of CP was related to the remodeling of the brain. We investigate the roles of iron overload and subsequent oxidative stress in the remodeling of the brain after SCI. We established a rat model of central pain after SCI. Rats were divided randomly into four groups: SCI, sham operation, SCI plus deferoxamine (DFX) intervention, and SCI plus nitric oxide synthase (NOS) inhibitor treatment. Pain behavior was observed and thermal pain threshold was measured regularly, and brain levels of iron, transferrin receptor 1 (TfR1), ferritin (Fn), and lactoferrin (Lf), were detected in the different groups 12 weeks after establishment of the model. Rats demonstrated self-biting behavior after SCI. Furthermore, the latent period of thermal pain was reduced and iron levels in the hind limb sensory area, hippocampus, and thalamus increased after SCI. Iron-regulatory protein (IRP) 1 levels increased in the hind limb sensory area, while Fn levels decreased. TfR1 mRNA levels were also increased and oxidative stress was activated. Oxidative stress could be inhibited by ferric iron chelators and NOS inhibitors. SCI may cause intracranial iron overload through the NOS-iron-responsive element/IRP pathway, resulting in central pain mediated by the oxidative stress response. Iron chelators and oxidative stress inhibitors can effectively relieve SCI-associated central pain.
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Spinal Cord Injury and Migraine Headache: A Population-Based Study
Warner, Freda M.; Cragg, Jacquelyn J.; Weisskopf, Marc G.; Kramer, John K.
2015-01-01
Migraine headaches are a common neurological condition, negatively impacting health and quality of life. Among potential risk factors for migraine headache, risk of migraine headaches was elevated in individuals with spinal cord injury (SCI). The association between migraines and SCI is intriguing to consider from the perspective that migraine headaches may be acquired in response to damage in the spinal cord. The primary objective of this study was to further examine the association between SCI and migraine headache, controlling for potential confounding variables. A secondary objective was to determine the impact of migraine headaches on self-perceived health. Data from a sample of 61,047 participants were obtained from the cross-sectional Canadian Community Health Survey. Multivariable logistic regression was used to explore the association between SCI and migraine headache using probability weights and adjusting for confounders. The multivariable age- and sex-adjusted model revealed a strong association between SCI and migraine headache, with an adjusted odds ratio for migraine of 4.82 (95% confidence interval [3.02, 7.67]) among those with SCI compared to those without SCI. Further, individuals who experienced both SCI and migraine tended to report poorer perceived general health compared with the other groups (i.e., SCI and no migraine). In conclusion, this study established a strong association between SCI and migraine headache. Further research is needed to explore the possible mechanisms underlying this relationship. Improvements in clinical practice to minimize this issue could result in significant improvements in quality of life. PMID:26308549
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Kathiresan, Anupama S Q; Ibrahim, Emad; Aballa, Teodoro C; Attia, George R; Ory, Steven J; Hoffman, David I; Maxson, Wayne S; Barrionuevo, Marcelo J; Lynne, Charles M; Brackett, Nancy L
2011-09-01
To determine if outcomes after in vitro fertilization with intracytoplasmic sperm injection (IVF/ICSI) using sperm from men with spinal cord injury (SCI group) differ from those of other etiologies of male factor infertility (non-SCI group). In men with SCI, to determine if IVF/ICSI outcomes differ with sperm obtained by penile vibratory stimulation (PVS group) versus electroejaculation (EEJ group). Retrospective analysis. University medical center and major infertility center. Couples with male factor infertility due to SCI versus other etiologies. PVS, EEJ, surgical sperm retrieval, and IVF/ICSI. Rates of fertilization, pregnancy, and live birth. A total of 31 couples in the SCI group underwent 48 cycles of IVF/ICSI, and a total of 297 couples in the non-SCI group underwent 443 cycles of IVF/ICSI. The SCI group had lower fertilization rates but similar pregnancy and live birth rates compared with the non-SCI group. These rates, however, did not differ significantly when the PVS group was compared with the EEJ group. IVF/ICSI of sperm from men with SCI yield lower fertilization rates but similar pregnancy and live birth outcomes as IVF/ICSI of sperm from men with other etiologies of male factor infertility. Sperm collected by PVS versus EEJ in men with SCI appear to result in similar IVF/ICSI success rates. Copyright © 2011 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.
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Molina, B; Segura, A; Serrano, J P; Alonso, F J; Molina, L; Pérez-Borrego, Y A; Ugarte, M I; Oliviero, A
2018-02-22
Cross-sectional study. To assess the impact of spinal cord injury (SCI) on cognitive function in individuals with subacute and chronic SCI. National Hospital for SCI patients (Spain). The present investigation was designed to determine the nature, pattern, and extent of cognitive deficits in a group of participants with subacute (n = 32) and chronic (n = 34) SCI, using a comprehensive battery of reliable and validated neuropsychological assessments to study a broad range of cognitive functions. Twenty-seven able-bodied subjects matched to the groups with SCI for age and educational level formed the control group. The neuropsychological assessment showed alterations in the domain of attention, processing speed, memory and learning, executive functions, and in recognition in participants with SCI. The prevalence of cognitive dysfunction in the chronic stage was also confirmed at the individual level. The comparison of the neuropsychological assessment between the groups with subacute and chronic SCI showed a worsening of cognitive functions in those with chronic SCI compared to the group with subacute SCI. In participants with SCI, cognitive dysfunctions are present in the subacute stage and worsen over time. From a clinical point of view, we confirmed the presence of cognitive dysfunction that may interfere with the first stage of rehabilitation which is the most intense and important. Moreover, cognitive dysfunction may be important beyond the end of the first stage of rehabilitation as it can affect an individual's quality of life and possible integration to society.
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NASA Astrophysics Data System (ADS)
Lian, Chao; Meng, Sheng
2017-06-01
Using density functional theory combined with orbital-selective band unfolding techniques, we study the effective band structure of silicene (3 ×3 )/Ag(111) (4 ×4 ) structure. Consistent with the ARPES spectra recently obtained by [Feng et al. Proc. Natl. Acad. Sci. USA 113, 14656 (2016), 10.1073/pnas.1613434114], we observe six pairs of Dirac cones near the boundary of the Brillouin zone (BZ) of Ag (1 ×1 ) , while no Dirac cone is observed inside the BZ. Furthermore, we find that these Dirac cones are induced by the interfacial Si-Ag hybridization, mainly composed of Si pz orbitals and Ag s p bands, which is intrinsically different from the Dirac cones in free-standing silicene.
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The pH-dependent surface charging and points of zero charge: V. Update.
Kosmulski, Marek
2011-01-01
The points of zero charge (PZC) and isoelectric points (IEP) from the recent literature are discussed. This study is an update of the previous compilation [M. Kosmulski, Surface Charging and Points of Zero Charge, CRC, Boca Raton, FL, 2009] and of its previous update [J. Colloid Interface Sci. 337 (2009) 439]. In several recent publications, the terms PZC/IEP have been used outside their usual meaning. Only the PZC/IEP obtained according to the methods recommended by the present author are reported in this paper, and the other results are ignored. PZC/IEP of albite, sepiolite, and sericite, which have not been studied before, became available over the past 2 years. Copyright © 2010 Elsevier Inc. All rights reserved.
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Mao, Ruifeng; Wu, Dongli; Hu, Shimeng; Zhou, Kangping; Wang, Man; Wang, Yefu
2017-04-01
Insulin plays an important role in drug therapies for diabetes mellitus and as the main route of insulin delivery, subcutaneous injection may cause local discomfort, hypoglycemia, hyperinsulinemia, and patient non-compliance. Therefore, oral delivery of insulin is more preferred. However, there is a low bioavailability due to insulin degradation by proteolytic enzymes and severe pH conditions along the gastrointestinal tract. In order to use the food-grade bacteria lactic acid bacteria (LAB) as oral delivery vehicles, a new and bioactive single-chain insulin (SCI-59) analog, containing the insulin B- and A-chains connected by an eight-residue linker (RSRGLPFR), was secretory expressed in Lactococcus lactis NZ3900 without using an antibiotic resistance gene and displayed onto the surface of various non-viable bacteria (NVBs) without genetic modification. Both the free SCI-59 and SCI-59 displayed on the surface of NVBs are biologically active as assayed by their ability to stimulate Akt signaling in differentiated 3T3-L1 adipocytes. Modification of the pH of the medium by NaOH addition at early time during induction can enhance the bioactivity of SCI-59. The C-terminal fused anchoring domain, three LysM repeats, does not affect the formation of disulfide bonds and/or the folding of SCI-59, and SCI-59 could be exposed properly and fully when SCI-59-3LysM bound to the surface of NVBs. Compared to the free form SCI-59, SCI-59 displayed on the surface of NVBs is more stable in simulate gastric juice. It may open new prospects for possible oral treatments of diabetes using live LAB secreting or NVBs carrying bioactive SCI analogs.
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Laginha, Inês; Kopp, Marcel A; Druschel, Claudia; Schaser, Klaus-Dieter; Brommer, Benedikt; Hellmann, Rick C; Watzlawick, Ralf; Ossami-Saidi, Ramin-Raul; Prüss, Harald; Failli, Vieri; Meisel, Christian; Liebscher, Thomas; Prilipp, Erik; Niedeggen, Andreas; Ekkernkamp, Axel; Grittner, Ulrike; Piper, Sophie K; Dirnagl, Ulrich; Killig, Monica; Romagnani, Chiara; Schwab, Jan M
2016-09-13
Natural killer (NK) cells comprise the main components of lymphocyte-mediated nonspecific immunity. Through their effector function they play a crucial role combating bacterial and viral challenges. They are also thought to be key contributors to the systemic spinal cord injury-induced immune-deficiency syndrome (SCI-IDS). SCI-IDS increases susceptibility to infection and extends to the post-acute and chronic phases after SCI. The prospective study of NK cell function after traumatic SCI was carried out in two centers in Berlin, Germany. SCI patients and control patients with neurologically silent vertebral fracture also undergoing surgical stabilization were enrolled. Furthermore healthy controls were included to provide reference data. The NK cell function was assessed at 7 (5-9) days, 14 days (11-28) days, and 10 (8-12) weeks post-trauma. Clinical documentation included the American Spinal Injury Association (ASIA) impairment scale (AIS), neurological level of injury, infection status, concomitant injury, and medications. The primary endpoint of the study is CD107a expression by NK cells (cytotoxicity marker) 8-12 weeks following SCI. Secondary endpoints are the NK cell's TNF-α and IFN-γ production by the NK cells 8-12 weeks following SCI. The protocol of this study was developed to investigate the hypotheses whether i) SCI impairs NK cell function throughout the post-acute and sub-acute phases after SCI and ii) the degree of impairment relates to lesion height and severity. A deeper understanding of the SCI-IDS is crucial to enable strategies for prevention of infections, which are associated with poor neurological outcome and elevated mortality. DRKS00009855 .
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Tulsky, David S; Kisala, Pamela A; Kalpakjian, Claire Z; Bombardier, Charles H; Pohlig, Ryan T; Heinemann, Allen W; Carle, Adam; Choi, Seung W
2015-05-01
To develop a calibrated spinal cord injury-quality of life (SCI-QOL) item bank, computer adaptive test (CAT), and short form to assess depressive symptoms experienced by individuals with SCI, transform scores to the Patient Reported Outcomes Measurement Information System (PROMIS) metric, and create a crosswalk to the Patient Health Questionnaire (PHQ)-9. We used grounded-theory based qualitative item development methods, large-scale item calibration field testing, confirmatory factor analysis, item response theory (IRT) analyses, and statistical linking techniques to transform scores to a PROMIS metric and to provide a crosswalk with the PHQ-9. Five SCI Model System centers and one Department of Veterans Affairs medical center in the United States. Adults with traumatic SCI. Spinal Cord Injury--Quality of Life (SCI-QOL) Depression Item Bank Individuals with SCI were involved in all phases of SCI-QOL development. A sample of 716 individuals with traumatic SCI completed 35 items assessing depression, 18 of which were PROMIS items. After removing 7 non-PROMIS items, factor analyses confirmed a unidimensional pool of items. We used a graded response IRT model to estimate slopes and thresholds for the 28 retained items. The SCI-QOL Depression measure correlated 0.76 with the PHQ-9. The SCI-QOL Depression item bank provides a reliable and sensitive measure of depressive symptoms with scores reported in terms of general population norms. We provide a crosswalk to the PHQ-9 to facilitate comparisons between measures. The item bank may be administered as a CAT or as a short form and is suitable for research and clinical applications.
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Saltzman, Jonah W.; Battaglino, Ricardo A.; Salles, Loise; Jha, Prateek; Sudhakar, Supreetha; Garshick, Eric; Stott, Helen L.; Zafonte, Ross
2013-01-01
Abstract Autoimmunity is thought to contribute to poor neurological outcomes after spinal cord injury (SCI). There are few mechanism-based therapies, however, designed to reduce tissue damage and neurotoxicity after SCI because the molecular and cellular bases for SCI-induced autoimmunity are not completely understood. Recent groundbreaking studies in rodents indicate that B cells are responsible for SCI-induced autoimmunity. This novel paradigm, if confirmed in humans, could aid in the design of neuroprotective immunotherapies. The aim of this study was to investigate the molecular signaling pathways and mechanisms by which autoimmunity is induced after SCI, with the goal of identifying potential targets in therapies designed to reduce tissue damage and inflammation in the chronic phase of SCI. To that end, we performed an exploratory microarray analysis of peripheral blood mononuclear cells to identify differentially expressed genes in chronic SCI. We identified a gene network associated with lymphoid tissue structure and development that was composed of 29 distinct molecules and five protein complexes, including two cytokines, a proliferation-inducing ligand (APRIL) and B-cell–activating factor (BAFF), and one receptor, B-cell maturation antigen (BMCA) involved in B cell development, proliferation, activation, and survival. Real-time polymerase chain reaction analysis from ribonucleic acid samples confirmed upregulation of these three genes in SCI. To our knowledge, this is the first report that peripheral blood mononuclear cells produce increased levels of BAFF and APRIL in chronic SCI. This finding provides evidence of systemic regulation of SCI-autoimmunity via APRIL and BAFF mediated activation of B cells through BMCA and points toward these molecules as potential targets of therapies designed to reduce neuroinflammation after SCI. PMID:23088438
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Characterization of the Antibody Response after Cervical Spinal Cord Injury
Ulndreaj, Antigona; Tzekou, Apostolia; Mothe, Andrea J.; Siddiqui, Ahad M.; Dragas, Rachel; Tator, Charles H.; Torlakovic, Emina E.
2017-01-01
Abstract The immune system plays a critical and complex role in the pathobiology of spinal cord injury (SCI), exerting both beneficial and detrimental effects. Increasing evidence suggests that there are injury level–dependent differences in the immune response to SCI. Patients with traumatic SCI have elevated levels of circulating autoantibodies against components of the central nervous system, but the role of these antibodies in SCI outcomes remains unknown. In rodent models of mid-thoracic SCI, antibody-mediated autoimmunity appears to be detrimental to recovery. However, whether autoantibodies against the spinal cord are generated following cervical SCI (cSCI), the most common level of injury in humans, remains undetermined. To address this knowledge gap, we investigated the antibody responses following cSCI in a rat model of injury. We found increased immunoglobulin G (IgG) and IgM antibodies in the spinal cord in the subacute phase of injury (2 weeks), but not in more chronic phases (10 and 20 weeks). At 2 weeks post-cSCI, antibodies were detected at the injury epicenter and co-localized with the astroglial scar and neurons of the ventral horn. These increased levels of antibodies corresponded with enhanced activation of immune responses in the spleen. Higher counts of antibody-secreting cells were observed in the spleen of injured rats. Further, increased levels of secreted IgG antibodies and enhanced proliferation of T-cells in splenocyte cultures from injured rats were found. These findings suggest the potential development of autoantibody responses following cSCI in the rat. The impact of the post-traumatic antibody responses on functional outcomes of cSCI is a critical topic that requires further investigation. PMID:27775474
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Exercise modulates chloride homeostasis after spinal cord injury.
Côté, Marie-Pascale; Gandhi, Sapan; Zambrotta, Marina; Houlé, John D
2014-07-02
Activity-based therapies are routinely integrated in spinal cord injury (SCI) rehabilitation programs because they result in a reduction of hyperreflexia and spasticity. However, the mechanisms by which exercise regulates activity in spinal pathways to reduce spasticity and improve functional recovery are poorly understood. Persisting alterations in the action of GABA on postsynaptic targets is a signature of CNS injuries, including SCI. The action of GABA depends on the intracellular chloride concentration, which is determined largely by the expression of two cation-chloride cotransporters (CCCs), KCC2 and NKCC1, which serve as chloride exporters and importers, respectively. We hypothesized that the reduction in hyperreflexia with exercise after SCI relies on a return to chloride homeostasis. Sprague Dawley rats received a spinal cord transection at T12 and were assigned to SCI-7d, SCI-14d, SCI-14d+exercise, SCI-28d, SCI-28d+exercise, or SCI-56d groups. During a terminal experiment, H-reflexes were recorded from interosseus muscles after stimulation of the tibial nerve and the low-frequency-dependent depression (FDD) was assessed. We provide evidence that exercise returns spinal excitability and levels of KCC2 and NKCC1 toward normal levels in the lumbar spinal cord. Acutely altering chloride extrusion using the KCC2 blocker DIOA masked the effect of exercise on FDD, whereas blocking NKCC1 with bumetanide returned FDD toward intact levels after SCI. Our results indicate that exercise contributes to reflex recovery and restoration of endogenous inhibition through a return to chloride homeostasis after SCI. This lends support for CCCs as part of a pathway that could be manipulated to improve functional recovery when combined with rehabilitation programs. Copyright © 2014 the authors 0270-6474/14/348976-12$15.00/0.
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Renno, Waleed M; Al-Khaledi, Ghanim; Mousa, Alyaa; Karam, Shaima M; Abul, Habib; Asfar, Sami
2014-02-01
Spinal cord injury (SCI) causes severe and long lasting motor and sensory deficits, chronic pain, and autonomic dysreflexia. (-)-epigallocatechin-3-gallate (EGCG) has shown to produce neuroprotective effect in a broad range of neurodegenerative disease animal models. This study designed to test the efficacy of intravenous infusion of EGCG for 36 h, in acutely injured rats' spinal cord: within first 4 h post-injury and, in chronically SC injured rats: after one year of injury. Functional outcomes measured using standard BBB scale, The Louisville Swim Scale (LSS) and, pain behavior assessment tests. 72 Female adult rats subjected to moderate thoracic SCI using MASCIS Impactor, blindly randomized as the following: (I) Acute SCI + EGCG (II) Acute SCI + saline. (III) Chronic SCI + EGCG. (IV) Chronic SCI + saline and, sham SCI animals. EGCG i.v. treatment of acute and, chronic SCI animals resulted in significantly better recovery of motor and sensory functions, BBB and LSS (P < 0.005) and (P < 0.05) respectively. Tactile allodynia, mechanical nociception (P < 0.05) significantly improved. Paw withdrawal and, tail flick latencies increase significantly (P < 0.05). Moreover, in the EGCG treated acute SCI animals the percentage of lesion size area significantly reduced (P < 0.0001) and, the number of neurons in the spinal cord increased (P < 0.001). Percent areas of GAP-43 and GFAP immunohistochemistry showed significant (P < 0.05) increase. We conclude that the therapeutic window of opportunity for EGCG to depict neurological recovery in SCI animals, is viable up to one year post SCI when intravenously infused for 36 h. Copyright © 2013 Elsevier Ltd. All rights reserved.
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Health Care Costs for Patients With Chronic Spinal Cord Injury in the Veterans Health Administration
French, Dustin D; Campbell, Robert R; Sabharwal, Sunil; Nelson, Audrey L; Palacios, Polly A; Gavin-Dreschnack, Deborah
2007-01-01
Background/Objective: Recurring annual costs of caring for patients with chronic spinal cord injury (SCI) is a large economic burden on health care systems, but information on costs of SCI care beyond the acute and initial postacute phase is sparse. The objective of this study was to establish a frame of reference and estimate of the annual direct medical costs associated with health care for a sample of patients with chronic SCI (ie, >2 years after injury). Methods: Patients were recruited from 3 Veterans Health Administration (VHA) SCI facilities; baseline patient information was cross-referenced to the Decision Support System (DSS) National Data Extracts (NDE) to obtain patient-specific health care costs in VHA. Descriptive statistical analysis of annual DSS-NDE cost of patients with SCI (N = 675) for fiscal year (FY) 2005 by level and completeness of injury was conducted. Results: Total (inpatient and outpatient) annual (FY 2005) direct medical costs for 675 patients with SCI exceeded $14.47 million or $21,450 per patient. Average annual total costs varied from $28,334 for cervical complete SCI to $16,792 for thoracic incomplete SCI. Two hundred thirty-three of the 675 patients with SCI who were hospitalized over the study period accounted for a total of 378 hospital discharges, costing in excess of $7.19 million. This approximated a cost of outpatient care received of $7.28 million for our entire sample. Conclusions: The comprehensive nature of health care delivery and related cost capture for people with chronic SCI in the VHA provided us the opportunity to accurately determine health care costs for this population. Future SCI postacute care cost analyses should consider case-mix adjusting patients at high risk for rehospitalization. PMID:18092564
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Shaw, T A; De Risio, L; Laws, E J; Rose, J H; Harcourt-Brown, T R; Granger, N
2017-05-01
Limited information is available about prognostic factors for recovery after spinal cord injury (SCI) to the L4-S3 segments. Previous research suggests that L4-S3 SCI does not have a worse prognosis than T3-L3 SCI. To elucidate prognostic factors for regaining urinary continence and ambulation in dogs with L4-S3 SCI and compare prognosis to T3-L3 SCI. A retrospective study on 61 nonambulatory dogs with L4-S3 SCI, matched to dogs with T3-L3 SCI, compared 3 weeks after onset. Prognostic factors explored using logistic regression and used for matching: nonchondrodystrophic dogs >15 kg versus dogs that were chondrodystrophic or <15 kg; compressive versus noncompressive lesions; presence versus absence of conscious pain perception (CPP); and lower vs upper motor neuron (LMN/UMN) incontinence. Fewer L4-S3 dogs regained continence compared to T3-L3 dogs (64 vs 85%, P = .0033), but no difference existed for regaining ambulation (66 vs 75%, P = .1306). In L4-S3 SCI dogs, fewer dogs regained continence with loss of CPP (P < .001), LMN incontinence (P = .004), and noncompressive lesions (P = .006). Negative prognostic factors for regaining ambulation included absent CPP (P < .001) and large nonchondrodystrophic breed (P = .022). Dogs with L4-S3 SCI have a poorer short-term prognosis than do dogs with T3-L3 SCI. Dogs with L4-S3 SCI had a poor prognosis with loss of CPP, or noncompressive lesions combined with LMN incontinence. Small-breed or chondrodystrophic dogs with retained CPP, compressive lesions, and UMN incontinence had an excellent prognosis. These findings may help guide decision-making in L4-S3 SCI. Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.
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Aquaporins in Spinal Cord Injury: The Janus Face of AQP4
Nesic, Olivera; Guest, James D.; Zivadinovic, Dragoslava; Narayana, Ponnada A.; Herrera, Juan J.; Grill, Raymond J.; Mokkapati, Venkata U.L.; Gelman, Benjamin B.; Lee, Julieann
2010-01-01
Although malfunction of spinal cord water channels (aquaporins, AQP) likely contributes to severe disturbances in ion/water homeostasis after spinal cord injury (SCI), their roles are still poorly understood. Here we report and discuss the potential significance of changes in the AQP4 expression in human SCI that generates GFAP-labeled astrocytes devoid of AQP4, and GFAP-labeled astroglia that overexpress AQP4. We used a rat model of contusion SCI to study observed changes in human SCI. AQP4-negative astrocytes are likely generated during the process of SCI-induced replacement of lost astrocytes, but their origin and role in SCI remains to be investigated. We found that AQP4-overexpression is likely triggered by hypoxia. Our transcriptional profiling of injured rat cords suggests that elevated AQP4-mediated water influx accompanies increased uptake of chloride and potassium ions which represents a protective astrocytic reaction to hypoxia. However, unbalanced water intake also results in astrocytic swelling that can contribute to motor impairment, but likely only in milder injuries. In severe rat SCI, a low abundance of AQP4-overexpressing astrocytes was found during the motor recovery phase. Our results suggest that severe rat contusion SCI is a better model to analyze AQP4 functions after SCI. We found that AQP4 increases in the chronic post-injury phase are associated with the development of pain-like behavior in SCI rats, while possible mechanisms underlying pain development may involve astrocytic swelling-induced glutamate release. In contrast, the formation and size of fluid-filled cavities occurring later after SCI does not appear to be affected by the extent of increased AQP4 levels. Therefore, the effect of therapeutic interventions targeting AQP4 will depend not only on the time interval after SCI or animal models, but also on the balance between protective role of increased AQP4 in hypoxia and deleterious effects of ongoing astrocytic swelling. PMID:20109536
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Coherent manipulation of photons and electrons
NASA Astrophysics Data System (ADS)
Zhao, Lu
In modern physics, coherent manipulation of photons and electrons has been intensively studied, and may have important applications in classical and quantum information processing. In this dissertation, we consider some interesting schemes to realize photonic and electronic coherent manipulation. In order to coherently manipulate photons, electromagnetically induced transparency (EIT) systems have been widely adopted because the optical response of EIT systems can be controlled by the laser-induced atomic coherence. In the second chapter, we theoretically investigate image storage in hot-vapor EIT media. A so-called 4f system is adopted for imaging, and an atomic vapor cell is placed over the transform plane. The Fraunhofer diffraction pattern of an object in the object plane can thus be transformed into atomic Raman coherence according to the idea of "light storage". We investigate how the stored diffraction pattern evolves under diffusion and discuss the essence of the stability of its dark spots. Our result indicates under appropriate conditions that an image can be reconstructed with high fidelity. The main reason for this procedure is the fact that diffusion of opposite-phase components of the diffraction pattern interfere destructively. In the third chapter, we show theoretical evidence that EIT systems can function as optically addressed spatial light modulators with megahertz modulation rates. The transverse spatial properties of continuous-wave probe fields can be modulated rapidly using two-dimensional optical patterns. To exemplify our proposal, we study real-time generation and manipulation of Laguerre-Gaussian beams by means of phase or amplitude modulation using flat-top image-bearing pulse trains as coupling fields in low-cost hot-vapor EIT systems. In order to coherently manipulate electrons, we consider graphene systems, including single-layer graphene and bilayer graphene, which have recently attracted considerable attention. Due to the long coherence length and electrically tunable Fermi levels, electrons in graphene systems have some photon-like behaviors, and could be coherently manipulated. Therefore, in the fourth chapter, we theorize that at a sharp electrostatic step potential in graphene massless Dirac fermions can obtain Goos-Hanchen-like shifts under total internal reflection. Also, we study coherent propagation of the quasiparticles along a sharp graphene p-n-p waveguide, and derive novel dispersion relations for the guided modes. Consequently, coherent graphene-based devices, e.g., movable mirrors, buffers and memories, induced only by the electric field effects may be proposed. Finally, we theoretically investigate the coherent propagation of massive chiral fermions along a sharp bilayer graphene p-n-p waveguide, and indicate that the guided quasiparticles can be coherently slowed, stored and retrieved based on tunable electric field effects. Controlling group velocity in the bilayer graphene p-n-p waveguide is accomplished via interband tunneling through the p-n interfaces, and does not depend on the bandgap opening.
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Yamaya, Seiji; Ozawa, Hiroshi; Kanno, Haruo; Kishimoto, Koshi N; Sekiguchi, Akira; Tateda, Satoshi; Yahata, Kenichiro; Ito, Kenta; Shimokawa, Hiroaki; Itoi, Eiji
2014-12-01
Extracorporeal shock wave therapy (ESWT) is widely used for the clinical treatment of various human diseases. Recent studies have demonstrated that low-energy ESWT upregulates the expression of vascular endothelial growth factor (VEGF) and promotes angiogenesis and functional recovery in myocardial infarction and peripheral artery disease. Many previous reports suggested that VEGF produces a neuroprotective effect to reduce secondary neural tissue damage after spinal cord injury (SCI). The purpose of the present study was to investigate whether low-energy ESWT promotes VEGF expression and neuroprotection and improves locomotor recovery after SCI. Sixty adult female Sprague-Dawley rats were randomly divided into 4 groups: sham group (laminectomy only), sham-SW group (low-energy ESWT applied after laminectomy), SCI group (SCI only), and SCI-SW group (low-energy ESWT applied after SCI). Thoracic spinal cord contusion injury was inflicted using an impactor. Low-energy ESWT was applied to the injured spinal cord 3 times a week for 3 weeks. Locomotor function was evaluated using the Basso, Beattie, and Bresnahan (BBB) Scale (open field locomotor score) at different time points over 42 days after SCI. Hematoxylin and eosin staining was performed to assess neural tissue damage in the spinal cord. Neuronal loss was investigated by immunostaining for NeuN. The mRNA expressions of VEGF and its receptor, Flt-1, in the spinal cord were assessed using real-time polymerase chain reaction. Immunostaining for VEGF was performed to evaluate VEGF protein expression in the spinal cord. In both the sham and sham-SW groups, no animals showed locomotor impairment on BBB scoring. Histological analysis of H & E and NeuN stainings in the sham-SW group confirmed that no neural tissue damage was induced by the low-energy ESWT. Importantly, animals in the SCI-SW group demonstrated significantly better locomotor improvement than those in the SCI group at 7, 35, and 42 days after injury (p < 0.05). The number of NeuN-positive cells in the SCI-SW group was significantly higher than that in the SCI group at 42 days after injury (p < 0.05). In addition, mRNA expressions of VEGF and Flt-1 were significantly increased in the SCI-SW group compared with the SCI group at 7 days after injury (p < 0.05). The expression of VEGF protein in the SCI-SW group was significantly higher than that in the SCI group at 7 days (p < 0.01). The present study showed that low-energy ESWT significantly increased expressions of VEGF and Flt-1 in the spinal cord without any detrimental effect. Furthermore, it significantly reduced neuronal loss in damaged neural tissue and improved locomotor function after SCI. These results suggested that low-energy ESWT enhances the neuroprotective effect of VEGF in reducing secondary injury and leads to better locomotor recovery following SCI. This study provides the first evidence that low-energy ESWT can be a safe and promising therapeutic strategy for SCI.
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Adapting Controlled-source Coherence Analysis to Dense Array Data in Earthquake Seismology
NASA Astrophysics Data System (ADS)
Schwarz, B.; Sigloch, K.; Nissen-Meyer, T.
2017-12-01
Exploration seismology deals with highly coherent wave fields generated by repeatable controlled sources and recorded by dense receiver arrays, whose geometry is tailored to back-scattered energy normally neglected in earthquake seismology. Owing to these favorable conditions, stacking and coherence analysis are routinely employed to suppress incoherent noise and regularize the data, thereby strongly contributing to the success of subsequent processing steps, including migration for the imaging of back-scattering interfaces or waveform tomography for the inversion of velocity structure. Attempts have been made to utilize wave field coherence on the length scales of passive-source seismology, e.g. for the imaging of transition-zone discontinuities or the core-mantle-boundary using reflected precursors. Results are however often deteriorated due to the sparse station coverage and interference of faint back-scattered with transmitted phases. USArray sampled wave fields generated by earthquake sources at an unprecedented density and similar array deployments are ongoing or planned in Alaska, the Alps and Canada. This makes the local coherence of earthquake data an increasingly valuable resource to exploit.Building on the experience in controlled-source surveys, we aim to extend the well-established concept of beam-forming to the richer toolbox that is nowadays used in seismic exploration. We suggest adapted strategies for local data coherence analysis, where summation is performed with operators that extract the local slope and curvature of wave fronts emerging at the receiver array. Besides estimating wave front properties, we demonstrate that the inherent data summation can also be used to generate virtual station responses at intermediate locations where no actual deployment was performed. Owing to the fact that stacking acts as a directional filter, interfering coherent wave fields can be efficiently separated from each other by means of coherent subtraction. We propose to construct exploration-type trace gathers, systematically investigate the potential to improve the quality and regularity of realistic synthetic earthquake data and present attempts at separating transmitted and back-scattered wave fields for the improved imaging of Earth's large-scale discontinuities.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Dong, Ban Xuan; Strzalka, Joseph; Jiang, Zhang
Although spin casting and chemical surface reactions are the most common methods used for fabricating functional polymer films onto substrates, they are limited with regard to producing films of certain morphological characteristics on different wetting and nonwetting substrates. The matrix-assisted pulsed laser evaporation (MAPLE) technique offers advantages with regard to producing films of different morphologies on different types of substrates. Here, we provide a quantitative characterization, using X-ray diffraction and optical methods, to elucidate the additive growth mechanism of MAPLE-deposited poly(3-hexylthiophene) (P3HT) films on substrates that have undergone different surface treatments, enabling them to possess different wettabilities. We show thatmore » MAPLE-deposited films are composed of crystalline phases, wherein the overall P3HT aggregate size and crystallite coherence length increase with deposition time. A complete pole figure constructed from X-ray diffraction measurements reveals that in these MAPLE-deposited films, there exist two distinct crystallite populations: (i) highly oriented crystals that grow from the flat dielectric substrate and (ii) misoriented crystals that preferentially grow on top of the existing polymer layers. The growth of the highly oriented crystals is highly sensitive to the chemistry of the substrate, whereas the effect of substrate chemistry on misoriented crystal growth is weaker. The use of a self-assembled monolayer to treat the substrate greatly enhances the population and crystallite coherence length at the buried interfaces, particularly during the early stage of deposition. Furthermore, the evolution of the in-plane carrier mobilities during the course of deposition is consistent with the development of highly oriented crystals at the buried interface, suggesting that this interface plays a key role toward determining carrier transport in organic thin-film transistors.« less
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Lin, Chun-Li; Kuo, Wen-Chuan; Yu, Jin-Jie; Huang, Shao-Fu
2013-04-01
CAD/CAM ceramic restorative material is routinely bonded to tooth substrates using adhesive cement. This study investigates micro-crack growth and damage in the ceramic/dentin adhesive interface under fatigue shear testing monitored using the acoustic emission (AE) technique with optical coherence tomography (OCT). Ceramic/dentin adhesive samples were prepared to measure the shear bond strength (SBS) under static load. Fatigue shear testing was performed using a modified ISO14801 method. Loads in the fatigue tests were applied at 80%, 70%, and 60% of the SBS to monitor interface debonding. The AE technique was used to detect micro-crack signals in static and fatigue shear bond tests. The results showed that the average SBS value in the static tests was 10.61±2.23MPa (mean±standard deviation). The average number of fatigue cycles in which ceramic/dentin interface damage was detected in 80%, 70% and 60% of the SBS were 152, 1962 and 9646, respectively. The acoustic behavior varied according to the applied load level. Events were emitted during 60% and 70% fatigue tests. A good correlation was observed between crack location in OCT images and the number of AE signal hits. The AE technique and OCT images employed in this study could potentially be used as a pre-clinical assessment tool to determine the integrity of cemented load bearing restored ceramic material. Sustainable cyclic load stresses in ceramic/dentin-bonded specimens were substantially lower than the measured SBS. Predicted S-N curve showed that the maximum endured load was 4.18MPa passing 10(6) fatigue cyclic. Copyright © 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
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Dong, Ban Xuan; Strzalka, Joseph; Jiang, Zhang; ...
2017-11-23
Although spin casting and chemical surface reactions are the most common methods used for fabricating functional polymer films onto substrates, they are limited with regard to producing films of certain morphological characteristics on different wetting and nonwetting substrates. The matrix-assisted pulsed laser evaporation (MAPLE) technique offers advantages with regard to producing films of different morphologies on different types of substrates. Here, we provide a quantitative characterization, using X-ray diffraction and optical methods, to elucidate the additive growth mechanism of MAPLE-deposited poly(3-hexylthiophene) (P3HT) films on substrates that have undergone different surface treatments, enabling them to possess different wettabilities. We show thatmore » MAPLE-deposited films are composed of crystalline phases, wherein the overall P3HT aggregate size and crystallite coherence length increase with deposition time. A complete pole figure constructed from X-ray diffraction measurements reveals that in these MAPLE-deposited films, there exist two distinct crystallite populations: (i) highly oriented crystals that grow from the flat dielectric substrate and (ii) misoriented crystals that preferentially grow on top of the existing polymer layers. The growth of the highly oriented crystals is highly sensitive to the chemistry of the substrate, whereas the effect of substrate chemistry on misoriented crystal growth is weaker. The use of a self-assembled monolayer to treat the substrate greatly enhances the population and crystallite coherence length at the buried interfaces, particularly during the early stage of deposition. Furthermore, the evolution of the in-plane carrier mobilities during the course of deposition is consistent with the development of highly oriented crystals at the buried interface, suggesting that this interface plays a key role toward determining carrier transport in organic thin-film transistors.« less
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Titiyal, Jeewan S; Kaur, Manpreet; Falera, Ruchita; Jose, Cijin P; Sharma, Namrata
2016-04-01
To evaluate the time to donor lenticule apposition in cases of Descemet stripping automated endothelial keratoplasty (DSAEK) using microscope-integrated intraoperative optical coherence tomography (iOCT). Thirty eyes of 27 patients planned to undergo Descemet stripping automated endothelial keratoplasty were enrolled in this prospective study. In group I (n = 10), continuous intracameral positive pressure was maintained for 8 minutes. In group II (n = 10) and group III (n = 10), external corneal massage was initiated simultaneously with positive intracameral air pressure. The external corneal massage was continued till complete resolution of interface fluid; the positive intracameral pressure was maintained for 8 minutes in group II and for 5 minutes in group III. The host-donor relationship was continuously monitored with the iOCT. The main outcome measure was time to complete donor lenticule apposition. In group I, the interface fluid persisted after 8 minutes of positive intracameral pressure in all eyes (10/10); hence an external corneal massage was required to achieve optimal donor adherence. In groups II and III, all eyes (20/20) had complete resolution of the interface fluid at the end of 3 minutes. In 100% of the eyes (30/30), the grafts were attached after anterior chamber decompression as seen on the iOCT. In all cases, the donor lenticules were adhered in the postoperative period. iOCT helps in understanding that the donor lenticule is well apposed within 1 to 3 minutes with the technique of simultaneous positive intracameral pressure and external corneal massage. This knowledge minimizes the waiting time for graft apposition and prevents prolonged intraocular pressure elevation.
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Adhi, Mehreen; Badaro, Emmerson; Liu, Jonathan J; Kraus, Martin F; Baumal, Caroline R; Witkin, Andre J; Hornegger, Joachim; Fujimoto, James G; Duker, Jay S; Waheed, Nadia K
2016-02-01
To analyze the vitreoretinal interface in diabetic eyes using 3-dimensional wide-field volumes acquired using high-speed, long-wavelength swept-source optical coherence tomography (SSOCT). Prospective cross-sectional study. Fifty-six diabetic patients (88 eyes) and 11 healthy nondiabetic controls (22 eyes) were recruited. Up to 8 SSOCT volumes were acquired for each eye. A registration algorithm removed motion artifacts and merged multiple SSOCT volumes to improve signal. Vitreous visualization was enhanced using vitreous windowing method. Of 88 diabetic eyes, 20 eyes had no retinopathy, 21 eyes had nonproliferative diabetic retinopathy (NPDR) without macular edema, 20 eyes had proliferative diabetic retinopathy (PDR) without macular edema, and 27 eyes had diabetic macular edema (DME) with either NPDR or PDR. Thick posterior hyaloid relative to healthy nondiabetic controls was observed in 0 of 20 (0%) diabetic eyes without retinopathy, 4 of 21 (19%) eyes with NPDR, 11 of 20 (55%) eyes with PDR, and 11 of 27 (41%) eyes with DME (P = .0001). Vitreoschisis was observed in 6 of 22 (27%) healthy nondiabetic eyes, 9 of 20 (45%) diabetic eyes without retinopathy, 10 of 21 (48%) eyes with NPDR, 13 of 20 (65%) eyes with PDR, and 17 of 27 (63%) eyes with DME (P = .007). While no healthy nondiabetic controls and diabetic eyes without retinopathy had adhesions/pegs between detached posterior hyaloid and retina, 1 of 21 (4%), 11 of 20 (55%), and 11 of 27 (41%) eyes with NPDR, PDR, and DME, respectively, demonstrated this feature (P = .0001). SSOCT with motion-correction and vitreous windowing provides wide-field 3-dimensional information of vitreoretinal interface in diabetic eyes. This may be useful in assessing progression of retinopathy, planning diabetic vitreous surgery, and predicting treatment outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.
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Specification for Visual Requirements of Work-Centered Software Systems
2006-10-01
no person shall be subject to any penity for fallng to comply wih a collection of N ilo ration it does not display a currenty valid OMB control...work- aiding systems. Based on the design concept for a work- centered support system (WCSS), these software systems support user tasks and goals...through both direct and indirect aiding methods within the interface client. In order to ensure the coherent development and delivery of work- centered
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Tunable infrared reflectance by phonon modulation
Ihlefeld, Jon F.; Sinclair, Michael B.; Beechem, III, Thomas E.
2018-03-06
The present invention pertains to the use of mobile coherent interfaces in a ferroelectric material to interact with optical phonons and, ultimately, to affect the material's optical properties. In altering the optical phonon properties, the optical properties of the ferroelectric material in the spectral range near-to the phonon mode frequency can dramatically change. This can result in a facile means to change to the optical response of the ferroelectric material in the infrared.
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MadSciNet: The 24-hour exploding laboratory.
Page New! Help Improve The Madsci Network Help Support MadSci MAD Head MAD egg Welcome to the laboratory that never sleeps! MadSci Network represents a collective cranium of scientists providing answers Sunday May 27, 2018. Lynn MadSci Network is a non-profit organization operating in partnership with Third
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32 CFR 171.6 - Reutilization and transfer procedures.
Code of Federal Regulations, 2010 CFR
2010-07-01
..., it shall send a written notice of dispute to the owning Military Service and ADUSD(L&MR/SCI) within thirty (30) days of its notice from the Military Service. ADUSD(L&MR/SCI) shall then resolve the dispute... and ADUSD(L&MR/SCI) within thirty (30) days of its notice from the Military Service. ADUSD(L&MR/SCI...
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32 CFR 171.6 - Reutilization and transfer procedures.
Code of Federal Regulations, 2011 CFR
2011-07-01
..., it shall send a written notice of dispute to the owning Military Service and ADUSD(L&MR/SCI) within thirty (30) days of its notice from the Military Service. ADUSD(L&MR/SCI) shall then resolve the dispute... and ADUSD(L&MR/SCI) within thirty (30) days of its notice from the Military Service. ADUSD(L&MR/SCI...
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Mukaino, Masahiko; Ono, Takashi; Shindo, Keiichiro; Fujiwara, Toshiyuki; Ota, Tetsuo; Kimura, Akio; Liu, Meigen; Ushiba, Junichi
2014-04-01
Brain computer interface technology is of great interest to researchers as a potential therapeutic measure for people with severe neurological disorders. The aim of this study was to examine the efficacy of brain computer interface, by comparing conventional neuromuscular electrical stimulation and brain computer interface-driven neuromuscular electrical stimulation, using an A-B-A-B withdrawal single-subject design. A 38-year-old male with severe hemiplegia due to a putaminal haemorrhage participated in this study. The design involved 2 epochs. In epoch A, the patient attempted to open his fingers during the application of neuromuscular electrical stimulation, irrespective of his actual brain activity. In epoch B, neuromuscular electrical stimulation was applied only when a significant motor-related cortical potential was observed in the electroencephalogram. The subject initially showed diffuse functional magnetic resonance imaging activation and small electro-encephalogram responses while attempting finger movement. Epoch A was associated with few neurological or clinical signs of improvement. Epoch B, with a brain computer interface, was associated with marked lateralization of electroencephalogram (EEG) and blood oxygenation level dependent responses. Voluntary electromyogram (EMG) activity, with significant EEG-EMG coherence, was also prompted. Clinical improvement in upper-extremity function and muscle tone was observed. These results indicate that self-directed training with a brain computer interface may induce activity- dependent cortical plasticity and promote functional recovery. This preliminary clinical investigation encourages further research using a controlled design.
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Schauwvlieghe, Pieter-Paul; Torre, Kara Della; Coppieters, Frauke; Van Hoey, Anneleen; De Baere, Elfride; De Zaeytijd, Julie; Leroy, Bart P; Brodie, Scott E
2013-01-01
To describe the phenotype of three cases of Sjögren reticular dystrophy in detail, including high-resolution optical coherence tomography, autofluorescence imaging, and near-infrared reflectance imaging. Two unrelated teenagers were independently referred for ophthalmologic evaluation. Both underwent a full ophthalmologic workup, including electrophysiologic and extensive imaging with spectral-domain optical coherence tomography, autofluorescence imaging, and near-infrared reflectance imaging. In addition, mutation screening of ABCA4, PRPH2, and the mitochondrial tRNA gene was performed in Patient 1. Subsequently, the teenage sister of Patient 2 was examined. Strikingly similar phenotypes were present in these three patients. Fundoscopy showed bilateral foveal pigment alterations, and a lobular network of deep retinal, pigmented deposits throughout the posterior pole, tapering toward the midperiphery, with relative sparing of the immediate perifoveal macula and peripapillary area. This network is mildly to moderately hyperautofluorescent on autofluorescence and bright on near-infrared reflectance imaging. Optical coherence tomography showed abnormalities of the retinal pigment epithelium-Bruch membrane complex, photoreceptor outer segments, and photoreceptor inner/outer segment interface. The results of retinal function test were entirely normal. No molecular cause was detected in Patient 1. Imaging suggested that the lobular network of deep retinal deposits in Sjögren reticular dystrophy is the result of accumulation of both pigment and lipofuscin between photoreceptors and retinal pigment epithelium, as well as within the retinal pigment epithelium.
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Corbett, Elaine A; Sachs, Nicholas A; Körding, Konrad P; Perreault, Eric J
2014-01-01
Cervical spinal cord injury (SCI) paralyzes muscles of the hand and arm, making it difficult to perform activities of daily living. Restoring the ability to reach can dramatically improve quality of life for people with cervical SCI. Any reaching system requires a user interface to decode parameters of an intended reach, such as trajectory and target. A challenge in developing such decoders is that often few physiological signals related to the intended reach remain under voluntary control, especially in patients with high cervical injuries. Furthermore, the decoding problem changes when the user is controlling the motion of their limb, as opposed to an external device. The purpose of this study was to investigate the benefits of combining disparate signal sources to control reach in people with a range of impairments, and to consider the effect of two feedback approaches. Subjects with cervical SCI performed robot-assisted reaching, controlling trajectories with either shoulder electromyograms (EMGs) or EMGs combined with gaze. We then evaluated how reaching performance was influenced by task-related sensory feedback, testing the EMG-only decoder in two conditions. The first involved moving the arm with the robot, providing congruent sensory feedback through their remaining sense of proprioception. In the second, the subjects moved the robot without the arm attached, as in applications that control external devices. We found that the multimodal-decoding algorithm worked well for all subjects, enabling them to perform straight, accurate reaches. The inclusion of gaze information, used to estimate target location, was especially important for the most impaired subjects. In the absence of gaze information, congruent sensory feedback improved performance. These results highlight the importance of proprioceptive feedback, and suggest that multi-modal decoders are likely to be most beneficial for highly impaired subjects and in tasks where such feedback is unavailable.
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ARC: An open-source library for calculating properties of alkali Rydberg atoms
NASA Astrophysics Data System (ADS)
Šibalić, N.; Pritchard, J. D.; Adams, C. S.; Weatherill, K. J.
2017-11-01
We present an object-oriented Python library for the computation of properties of highly-excited Rydberg states of alkali atoms. These include single-body effects such as dipole matrix elements, excited-state lifetimes (radiative and black-body limited) and Stark maps of atoms in external electric fields, as well as two-atom interaction potentials accounting for dipole and quadrupole coupling effects valid at both long and short range for arbitrary placement of the atomic dipoles. The package is cross-referenced to precise measurements of atomic energy levels and features extensive documentation to facilitate rapid upgrade or expansion by users. This library has direct application in the field of quantum information and quantum optics which exploit the strong Rydberg dipolar interactions for two-qubit gates, robust atom-light interfaces and simulating quantum many-body physics, as well as the field of metrology using Rydberg atoms as precise microwave electrometers. Program Files doi:http://dx.doi.org/10.17632/hm5n8w628c.1 Licensing provisions: BSD-3-Clause Programming language: Python 2.7 or 3.5, with C extension External Routines: NumPy [1], SciPy [1], Matplotlib [2] Nature of problem: Calculating atomic properties of alkali atoms including lifetimes, energies, Stark shifts and dipole-dipole interaction strengths using matrix elements evaluated from radial wavefunctions. Solution method: Numerical integration of radial Schrödinger equation to obtain atomic wavefunctions, which are then used to evaluate dipole matrix elements. Properties are calculated using second order perturbation theory or exact diagonalisation of the interaction Hamiltonian, yielding results valid even at large external fields or small interatomic separation. Restrictions: External electric field fixed to be parallel to quantisation axis. Supplementary material: Detailed documentation (.html), and Jupyter notebook with examples and benchmarking runs (.html and .ipynb). [1] T.E. Oliphant, Comput. Sci. Eng. 9, 10 (2007). http://www.scipy.org/. [2] J.D. Hunter, Comput. Sci. Eng. 9, 90 (2007). http://matplotlib.org/.
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Grous, Lauren Conova; Vernengo, Jennifer; Jin, Ying; Himes, B. Timothy; Shumsky, Jed S.; Fischer, Itzhak; Lowman, Anthony
2016-01-01
Object In a follow-up study to their prior work, the authors evaluated a novel delivery system for a previously established treatment for spinal cord injury (SCI), based on a poly(N-isopropylacrylamide) (PNIPAAm), lightly cross-linked with a polyethylene glycol (PEG) injectable scaffold. The primary aim of this work was to assess the recovery of both spontaneous and skilled forelimb function following a cervical dorsolateral funiculotomy in the rat. This injury ablates the rubrospinal tract (RST) but spares the dorsal and ventral corticospinal tract and can severely impair reaching and grasping abilities. Methods Animals received an implant of either PNIPAAm-g-PEG or PNIPAAm-g-PEG + brain-derived neurotrophic factor (BDNF). The single-pellet reach-to-grasp task and the staircase-reaching task were used to assess skilled motor function associated with reaching and grasping abilities, and the cylinder task was used to assess spontaneous motor function, both before and after injury. Results Because BDNF can stimulate regenerating RST axons, the authors showed that animals receiving an implant of PNIPAAm-g-PEG with codissolved BDNF had an increased recovery rate of fine motor function when compared with a control group (PNIPAAm-g-PEG only) on both a staircase-reaching task at 4 and 8 weeks post-SCI and on a single-pellet reach-to-grasp task at 5 weeks post-SCI. In addition, spontaneous motor function, as measured in the cylinder test, recovered to preinjury values in animals receiving PNIPAAm-g-PEG + BDNF. Fluorescence immunochemistry indicated the presence of both regenerating axons and BDA-labeled fibers growing up to or within the host-graft interface in animals receiving PNIPAAm-g-PEG + BDNF. Conclusions Based on their results, the authors suggest that BDNF delivered by the scaffold promoted the growth of RST axons into the lesion, which may have contributed in part to the increased recovery rate. PMID:23581453
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On a novel low cost high accuracy experimental setup for tomographic particle image velocimetry
NASA Astrophysics Data System (ADS)
Discetti, Stefano; Ianiro, Andrea; Astarita, Tommaso; Cardone, Gennaro
2013-07-01
This work deals with the critical aspects related to cost reduction of a Tomo PIV setup and to the bias errors introduced in the velocity measurements by the coherent motion of the ghost particles. The proposed solution consists of using two independent imaging systems composed of three (or more) low speed single frame cameras, which can be up to ten times cheaper than double shutter cameras with the same image quality. Each imaging system is used to reconstruct a particle distribution in the same measurement region, relative to the first and the second exposure, respectively. The reconstructed volumes are then interrogated by cross-correlation in order to obtain the measured velocity field, as in the standard tomographic PIV implementation. Moreover, differently from tomographic PIV, the ghost particle distributions of the two exposures are uncorrelated, since their spatial distribution is camera orientation dependent. For this reason, the proposed solution promises more accurate results, without the bias effect of the coherent ghost particles motion. Guidelines for the implementation and the application of the present method are proposed. The performances are assessed with a parametric study on synthetic experiments. The proposed low cost system produces a much lower modulation with respect to an equivalent three-camera system. Furthermore, the potential accuracy improvement using the Motion Tracking Enhanced MART (Novara et al 2010 Meas. Sci. Technol. 21 035401) is much higher than in the case of the standard implementation of tomographic PIV.
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Dvorak, Marcel F; Cheng, Christiana L; Fallah, Nader; Santos, Argelio; Atkins, Derek; Humphreys, Suzanne; Rivers, Carly S; White, Barry A B; Ho, Chester; Ahn, Henry; Kwon, Brian K; Christie, Sean; Noonan, Vanessa K
2017-10-15
Timely access and ongoing delivery of care and therapeutic interventions is needed to maximize recovery and function after traumatic spinal cord injury (tSCI). To ensure these decisions are evidence-based, access to consistent, reliable, and valid sources of clinical data is required. The Access to Care and Timing Model used data from the Rick Hansen SCI Registry (RHSCIR) to generate a simulation of healthcare delivery for persons after tSCI and to test scenarios aimed at improving outcomes and reducing the economic burden of SCI. Through model development, we identified knowledge gaps and challenges in the literature and current health outcomes data collection throughout the continuum of SCI care. The objectives of this article were to describe these gaps and to provide recommendations for bridging them. Accurate information on injury severity after tSCI was hindered by difficulties in conducting neurological assessments and classifications of SCI (e.g., timing), variations in reporting, and the lack of a validated SCI-specific measure of associated injuries. There was also limited availability of reliable data on patient factors such as multi-morbidity and patient-reported measures. Knowledge gaps related to structures (e.g., protocols) and processes (e.g., costs) at each phase of care have prevented comprehensive evaluation of system performance. Addressing these knowledge gaps will enhance comparative and cost-effectiveness evaluations to inform decision-making and standards of care. Recommendations to do so were: standardize data element collection and facilitate database linkages, validate and adopt more outcome measures for SCI, and increase opportunities for collaborations with stakeholders from diverse backgrounds.
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Cohen, Matthew L; Kisala, Pamela A; Dyson-Hudson, Trevor A; Tulsky, David S
2018-05-01
To develop modern patient-reported outcome measures that assess pain interference and pain behavior after spinal cord injury (SCI). Grounded-theory based qualitative item development; large-scale item calibration field-testing; confirmatory factor analyses; graded response model item response theory analyses; statistical linking techniques to transform scores to the Patient Reported Outcome Measurement Information System (PROMIS) metric. Five SCI Model Systems centers and one Department of Veterans Affairs medical center in the United States. Adults with traumatic SCI. N/A. Spinal Cord Injury - Quality of Life (SCI-QOL) Pain Interference item bank, SCI-QOL Pain Interference short form, and SCI-QOL Pain Behavior scale. Seven hundred fifty-seven individuals with traumatic SCI completed 58 items addressing various aspects of pain. Items were then separated by whether they assessed pain interference or pain behavior, and poorly functioning items were removed. Confirmatory factor analyses confirmed that each set of items was unidimensional, and item response theory analyses were used to estimate slopes and thresholds for the items. Ultimately, 7 items (4 from PROMIS) comprised the Pain Behavior scale and 25 items (18 from PROMIS) comprised the Pain Interference item bank. Ten of these 25 items were selected to form the Pain Interference short form. The SCI-QOL Pain Interference item bank and the SCI-QOL Pain Behavior scale demonstrated robust psychometric properties. The Pain Interference item bank is available as a computer adaptive test or short form for research and clinical applications, and scores are transformed to the PROMIS metric.
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Kisala, Pamela A; Tulsky, David S; Kalpakjian, Claire Z; Heinemann, Allen W; Pohlig, Ryan T; Carle, Adam; Choi, Seung W
2015-05-01
To develop a calibrated item bank and computer adaptive test to assess anxiety symptoms in individuals with spinal cord injury (SCI), transform scores to the Patient Reported Outcomes Measurement Information System (PROMIS) metric, and create a statistical linkage with the Generalized Anxiety Disorder (GAD)-7, a widely used anxiety measure. Grounded-theory based qualitative item development methods; large-scale item calibration field testing; confirmatory factor analysis; graded response model item response theory analyses; statistical linking techniques to transform scores to a PROMIS metric; and linkage with the GAD-7. Setting Five SCI Model System centers and one Department of Veterans Affairs medical center in the United States. Participants Adults with traumatic SCI. Spinal Cord Injury-Quality of Life (SCI-QOL) Anxiety Item Bank Seven hundred sixteen individuals with traumatic SCI completed 38 items assessing anxiety, 17 of which were PROMIS items. After 13 items (including 2 PROMIS items) were removed, factor analyses confirmed unidimensionality. Item response theory analyses were used to estimate slopes and thresholds for the final 25 items (15 from PROMIS). The observed Pearson correlation between the SCI-QOL Anxiety and GAD-7 scores was 0.67. The SCI-QOL Anxiety item bank demonstrates excellent psychometric properties and is available as a computer adaptive test or short form for research and clinical applications. SCI-QOL Anxiety scores have been transformed to the PROMIS metric and we provide a method to link SCI-QOL Anxiety scores with those of the GAD-7.
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Malinowsky, Camilla; Kottorp, Anders; Wallin, Anders; Nordlund, Arto; Björklund, Eva; Melin, Ilse; Pernevik, Anette; Rosenberg, Lena; Nygård, Louise
2017-07-01
To use valid subjective reports sensible to cognitive decline is vital to identify very early signs of dementia development. Use of everyday technology (ET) has been shown to be sensitive to differentiate adults with mild cognitive impairment (MCI) from controls, but the group with subjective cognitive impairment (SCI) has not yet been examined. This study aims to investigate and compare self-perceived ability in ET use and number of ETs reported as actually used in a sample of older adults with SCI, MCI, and older adults with no known cognitive impairment, i.e. Older adults with MCI (n = 29), SCI ( n = 26), and controls (n = 30) were interviewed with the short version of the Everyday Technology Use Questionnaire (S-ETUQ) to capture self-perceived ability in ET use and number of ETs used. To generate individual measures of ability to use ET, Rasch analysis was used. The measures were then compared group-wise using ANCOVA. The numbers of ETs used were compared group-wise with ANOVA. Controls versus SCI and MCI differed significantly regarding ETs reported as used, but not SCI versus MCI. Similarly, in ability to use ET, controls versus SCI and MCI differed significantly but not SCI versus MCI. The significantly lower numbers of ETs reported as actually used and the lower ability in SCI and MCI groups compared to controls suggest that ET use is affected already in very minor cognitive decline. This indicates that self-reported ET use based on the S-ETUQ is sensitive to detect changes already in SCI.
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Kriz, J; Kulakovska, M; Davidova, H; Silova, M; Kobesova, A
2017-09-01
A prospective study. Analysis of epidemiological data about acute spinal cord injury (SCI) in the Czech Republic over a period of 10 years (2006-2015). A data collection system was implemented in the rehabilitation centres which provides care to patients with acute SCI in the Czech Republic. The recorded variables are as follows: age at time of SCI; gender; cause of injury; neurological level of injury (NLI); and its severity (ASIA Impairment Scale (AIS)). Data from 2006 to 2015 were analysed and trends were determined. The overall number of acute SCI ranges between 250 and 300 cases annually. Two-third of the affected population are males. The average age at time of SCI is 49.1 years. The average incidence of traumatic SCI is 15.5 cases per year and is gradually decreasing. The leading cause of SCI are falls (44.5%), followed by traffic accidents (28.2%) and sports injuries including diving into water (19.7%). The incidence of non-traumatic SCI is 8.6 cases per year on average and has an upward trend. Inflammatory lesions account for 26.7% of cases, tumours account for 20.9%, and vascular related injuries make up 17.7%. The NLI occurs most often in the cervical segments (45.3%). The most frequently occurring lesions are motor incomplete: AIS D (33.3%). This study shows a stable occurrence of SCI in the Czech Republic, with cervical and motor incomplete cases being the leading ones. Epidemiological data are needed to improve the care of SCI patients and to promote an active life following it.
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Cheng, Christiana L.; Fallah, Nader; Santos, Argelio; Atkins, Derek; Humphreys, Suzanne; Rivers, Carly S.; White, Barry A.B.; Ho, Chester; Ahn, Henry; Kwon, Brian K.; Christie, Sean; Noonan, Vanessa K.
2017-01-01
Abstract Timely access and ongoing delivery of care and therapeutic interventions is needed to maximize recovery and function after traumatic spinal cord injury (tSCI). To ensure these decisions are evidence-based, access to consistent, reliable, and valid sources of clinical data is required. The Access to Care and Timing Model used data from the Rick Hansen SCI Registry (RHSCIR) to generate a simulation of healthcare delivery for persons after tSCI and to test scenarios aimed at improving outcomes and reducing the economic burden of SCI. Through model development, we identified knowledge gaps and challenges in the literature and current health outcomes data collection throughout the continuum of SCI care. The objectives of this article were to describe these gaps and to provide recommendations for bridging them. Accurate information on injury severity after tSCI was hindered by difficulties in conducting neurological assessments and classifications of SCI (e.g., timing), variations in reporting, and the lack of a validated SCI-specific measure of associated injuries. There was also limited availability of reliable data on patient factors such as multi-morbidity and patient-reported measures. Knowledge gaps related to structures (e.g., protocols) and processes (e.g., costs) at each phase of care have prevented comprehensive evaluation of system performance. Addressing these knowledge gaps will enhance comparative and cost-effectiveness evaluations to inform decision-making and standards of care. Recommendations to do so were: standardize data element collection and facilitate database linkages, validate and adopt more outcome measures for SCI, and increase opportunities for collaborations with stakeholders from diverse backgrounds. PMID:28745934
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Return to work following spinal cord injury: a review.
Lidal, Ingeborg Beate; Huynh, Tuan Khai; Biering-Sørensen, Fin
2007-09-15
To review literature on return to work (RTW) and employment in persons with spinal cord injury (SCI), and present employment rates, factors influencing employment, and interventions aimed at helping people with SCI to obtain and sustain productive work. A systematic review for 2000 - 2006 was carried out in PubMed/Medline, AMED, (ISI) Web of Science, EMBASE, CINAHL, PsycInfo and Sociological abstracts database. The keywords 'spinal cord injuries', 'spinal cord disorder', 'spinal cord lesion' or 'spinal cord disease' were cross-indexed with 'employment', 'return to work', 'occupation' or 'vocational'. Out of approximately 270 hits, 110 references were used, plus 13 more found elsewhere. Among individuals with SCI working at the time of injury 21 - 67% returned to work after injury. RTW was higher in persons injured at a younger age, had less severe injuries and higher functional independence. Employment rate improved with time after SCI. Persons with SCI employed ranged from 11.5% to 74%. Individuals who sustained SCI during childhood or adolescence had higher adult employment rates. Most common reported barriers to employment were problems with transportation, health and physical limitations, lack of work experience, education or training, physical or architectural barriers, discrimination by employers, and loss of benefits. Individuals with SCI discontinue working at younger age. This review confirmed low employment rates after SCI. Future research should explore interventions aimed at helping people with SCI to obtain and sustain productive work.
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32 CFR 154.77 - Reporting requirements.
Code of Federal Regulations, 2011 CFR
2011-07-01
... Secret, Secret, and Confidential clearances revoked; (4) Number of SCI access determinations issued; (5) Number of SCI access determinations denied; (6) Number of SCI access determinations revoked; and (7...
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Thirumala, Parthasarathy; Zhou, James; Krishnan, Rohan; Manem, Nihita; Umredkar, Shreya; Hamilton, D K; Balzer, Jeffrey R; Oudega, Martin
2016-03-01
Iatrogenic spinal cord injury (SCI) is a cause of potentially debilitating post-operative neurologic complications. Currently, intra-operative neurophysiological monitoring (IONM) via somatosensory evoked potentials and motor-evoked potentials is used to detect and prevent impending SCI. However, no empirically validated interventions exist to halt the progression of iatrogenic SCI once it is detected. This is in part due to the lack of a suitable translational model that mimics the circumstances surrounding iatrogenic SCI detected via IONM. Here, we evaluate a model of simulated contusive iatrogenic SCI detected via IONM in adult female Sprague-Dawley rats. We show that transient losses of somatosensory evoked potentials responses are 88.24% sensitive (95% confidence interval [CI] 63.53-98.20) and 80% specific (95% CI 51.91-95.43) for significant functional impairment following simulated iatrogenic SCI. Similarly, we show that transient losses in motor-evoked potentials responses are 70.83% sensitive (95% CI 48.91-87.33) and 100% specific (95% CI 62.91-100.00) for significant functional impairment following simulated iatrogenic SCI. These results indicate that our model is a suitable replica of the circumstances surrounding clinical iatrogenic SCI. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Effects of melatonin on spinal cord injury-induced oxidative damage in mice testis.
Yuan, X-C; Wang, P; Li, H-W; Wu, Q-B; Zhang, X-Y; Li, B-W; Xiu, R-J
2017-09-01
This study evaluated the effects of melatonin on spinal cord injury (SCI)-induced oxidative damage in testes. Adult male C57BL/6 mice were randomly divided into sham-, SCI- or melatonin (10 mg/kg, i.p.)-treated SCI groups. To induce SCI, a standard weight-drop method that induced a contusion injury at T10 was used. After 1 week, testicular blood flow velocity was measured using the Laser Doppler Line Scanner. Malondialdehyde (MDA), glutathione (GSH), oxidised glutathione (GSSG) and myeloperoxidase (MPO) were measured in testis homogenates. Microvascular permeability of the testes to Evan's Blue was examined by spectrophotometric and fluorescence microscopic quantitation. The tight junction protein zonula occludens-1 (ZO-1) and occludin in testes were assessed by immunoblot analysis. Melatonin increased the reduced blood flow and decreased SCI-induced permeability of capillaries. MDA levels and MPO activity were elevated in the SCI group compared with shams, which was reversed by melatonin. In contrast, SCI-induced reductions in GSH/GSSG ratio were restored by melatonin. Decreased expression of ZO-1 and occludin was observed, which was attenuated by melatonin. Overall, melatonin treatment protects the testes against oxidative stress damage caused by SCI. © 2016 Blackwell Verlag GmbH.
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Lv, Yan; Zhang, Liang; Li, Na; Mai, Naiken; Zhang, Yu; Pan, Shuyi
2017-12-01
Geraniol, a plant-derived monoterpene, has been extensively studied and showed a wide variety of beneficial effects. The aim of this study was to investigate the therapeutic effect of geraniol on functional recovery and neuropathic pain in rats with spinal cord injury (SCI). Rats received a clip-compression SCI and were treated with geraniol 6 h following SCI. Treatment of SCI rats with geraniol markedly improved locomotor function, and reduced sensitivity to the mechanical allodynia and thermal hyperalgesia. Treatment of SCI rats with geraniol increased NeuN-positive cells, suppressed expression of glial fibrillary acidic protein, and reduced activity of caspase-3 in the injured region. Treatment of SCI rats with geraniol reduced levels of malondialdehyde and 3-nitrotyrosine, upregulated protein expression of nuclear factor-erythroid 2-related factor 2 and heme oxygenase 1, and suppressed expression of inducible nitric oxide synthase in the injured region. In addition, treatment of SCI rats with geraniol downregulated protein expression of N-methyl-d-aspartate receptor 1 and reduced the number of CD68-positive cells and protein levels of TNF-α in the injured region. In conclusion, geraniol significantly promoted the recovery of neuronal function and attenuated neuropathic pain after SCI.
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Ruiz-Pérez, R.; López-Cózar, E. Delgado; Jiménez-Contreras, E.
2002-01-01
Objectives: The study sought to investigate how Spanish names are handled by national and international databases and to identify mistakes that can undermine the usefulness of these databases for locating and retrieving works by Spanish authors. Methods: The authors sampled 172 articles published by authors from the University of Granada Medical School between 1987 and 1996 and analyzed the variations in how each of their names was indexed in Science Citation Index (SCI), MEDLINE, and Índice Médico Español (IME). The number and types of variants that appeared for each author's name were recorded and compared across databases to identify inconsistencies in indexing practices. We analyzed the relationship between variability (number of variants of an author's name) and productivity (number of items the name was associated with as an author), the consequences for retrieval of information, and the most frequent indexing structures used for Spanish names. Results: The proportion of authors who appeared under more then one name was 48.1% in SCI, 50.7% in MEDLINE, and 69.0% in IME. Productivity correlated directly with variability: more than 50% of the authors listed on five to ten items appeared under more than one name in any given database, and close to 100% of the authors listed on more than ten items appeared under two or more variants. Productivity correlated inversely with retrievability: as the number of variants for a name increased, the number of items retrieved under each variant decreased. For the most highly productive authors, the number of items retrieved under each variant tended toward one. The most frequent indexing methods varied between databases. In MEDLINE and IME, names were indexed correctly as “first surname second surname, first name initial middle name initial” (if present) in 41.7% and 49.5% of the records, respectively. However, in SCI, the most frequent method was “first surname, first name initial second name initial” (48.0% of the records) and first surname and second surname run together, first name initial (18.3%). Conclusions: Retrievability on the basis of author's name was poor in all three databases. Each database uses accurate indexing methods, but these methods fail to result in consistency or coherence for specific entries. The likely causes of inconsistency are: (1) use by authors of variants of their names during their publication careers, (2) lack of authority control in all three databases, (3) the use of an inappropriate indexing method for Spanish names in SCI, (4) authors' inconsistent behaviors, and (5) possible editorial interventions by some journals. We offer some suggestions as to how to avert the proliferation of author name variants in the databases. PMID:12398248
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Tung, James Y; Stead, Brent; Mann, William; Ba'Pham; Popovic, Milos R
2015-01-01
Pressure ulcers (PUs) in individuals with spinal cord injury (SCI) present a persistent and costly problem. Continuing effort in developing new technologies that support self-managed care is an important prevention strategy. Specifically, the aims of this scoping review are to review the key concepts and factors related to self-managed prevention of PUs in individuals with SCI and appraise the technologies available to assist patients in self-management of PU prevention practices. There is broad consensus that sustaining long-term adherence to prevention regimens is a major concern. Recent literature highlights the interactions between behavioral and physiological risk factors. We identify four technology categories that support self-management: computer-based educational technologies demonstrated improved short-term gains in knowledge (2 studies), interface pressure mapping technologies demonstrated improved adherence to pressure-relief schedules up to 3 mo (5 studies), electrical stimulation confirmed improvements in tissue tolerance after 8 wk of training (3 studies), and telemedicine programs demonstrated improvements in independence and reduced hospital visits over 6 mo (2 studies). Overall, self-management technologies demonstrated low-to-moderate effectiveness in addressing a subset of risk factors. However, the effectiveness of technologies in preventing PUs is limited due to a lack of incidence reporting. In light of the key findings, we recommend developing integrated technologies that address multiple risk factors.
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Jain, Anjana; McKeon, Robert J.; Brady-Kalnay, Susann M.; Bellamkonda, Ravi V.
2011-01-01
Background Spinal cord injury (SCI) often results in permanent functional loss. This physical trauma leads to secondary events, such as the deposition of inhibitory chondroitin sulfate proteoglycan (CSPG) within astroglial scar tissue at the lesion. Methodology/Principal Findings We examined whether local delivery of constitutively active (CA) Rho GTPases, Cdc42 and Rac1 to the lesion site alleviated CSPG-mediated inhibition of regenerating axons. A dorsal over-hemisection lesion was created in the rat spinal cord and the resulting cavity was conformally filled with an in situ gelling hydrogel combined with lipid microtubes that slowly released constitutively active (CA) Cdc42, Rac1, or Brain-derived neurotrophic factor (BDNF). Treatment with BDNF, CA-Cdc42, or CA-Rac1 reduced the number of GFAP-positive astrocytes, as well as CSPG deposition, at the interface of the implanted hydrogel and host tissue. Neurofilament 160kDa positively stained axons traversed the glial scar extensively, entering the hydrogel-filled cavity in the treatments with BDNF and CA-Rho GTPases. The treated animals had a higher percentage of axons from the corticospinal tract that traversed the CSPG-rich regions located proximal to the lesion site. Conclusion Local delivery of CA-Cdc42, CA-Rac1, and BDNF may have a significant therapeutic role in overcoming CSPG-mediated regenerative failure after SCI. PMID:21283639
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Tidoni, Emmanuele; Gergondet, Pierre; Fusco, Gabriele; Kheddar, Abderrahmane; Aglioti, Salvatore M
2017-06-01
The efficient control of our body and successful interaction with the environment are possible through the integration of multisensory information. Brain-computer interface (BCI) may allow people with sensorimotor disorders to actively interact in the world. In this study, visual information was paired with auditory feedback to improve the BCI control of a humanoid surrogate. Healthy and spinal cord injured (SCI) people were asked to embody a humanoid robot and complete a pick-and-place task by means of a visual evoked potentials BCI system. Participants observed the remote environment from the robot's perspective through a head mounted display. Human-footsteps and computer-beep sounds were used as synchronous/asynchronous auditory feedback. Healthy participants achieved better placing accuracy when listening to human footstep sounds relative to a computer-generated sound. SCI people demonstrated more difficulty in steering the robot during asynchronous auditory feedback conditions. Importantly, subjective reports highlighted that the BCI mask overlaying the display did not limit the observation of the scenario and the feeling of being in control of the robot. Overall, the data seem to suggest that sensorimotor-related information may improve the control of external devices. Further studies are required to understand how the contribution of residual sensory channels could improve the reliability of BCI systems.
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Clinical interpretation of the Spinal Cord Injury Functional Index (SCI-FI)
Fyffe, Denise; Kalpakjian, Claire Z.; Slavin, Mary; Kisala, Pamela; Ni, Pengsheng; Kirshblum, Steven C.; Tulsky, David S.; Jette, Alan M.
2016-01-01
Objective: To provide validation of functional ability levels for the Spinal Cord Injury – Functional Index (SCI-FI). Design: Cross-sectional. Setting: Inpatient rehabilitation hospital and community settings. Participants: A sample of 855 individuals with traumatic spinal cord injury enrolled in 6 rehabilitation centers participating in the National Spinal Cord Injury Model Systems Network. Interventions: Not Applicable. Main Outcome Measures: Spinal Cord Injury-Functional Index (SCI-FI). Results: Cluster analyses identified three distinct groups that represent low, mid-range and high SCI-FI functional ability levels. Comparison of clusters on personal and other injury characteristics suggested some significant differences between groups. Conclusions: These results strongly support the use of SCI-FI functional ability levels to document the perceived functional abilities of persons with SCI. Results of the cluster analysis suggest that the SCI-FI functional ability levels capture function by injury characteristics. Clinical implications regarding tracking functional activity trajectories during follow-up visits are discussed. PMID:26781769
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Prüss, Harald; Tedeschi, Andrea; Thiriot, Aude; Lynch, Lydia; Loughhead, Scott M; Stutte, Susanne; Mazo, Irina B; Kopp, Marcel A; Brommer, Benedikt; Blex, Christian; Geurtz, Laura-Christin; Liebscher, Thomas; Niedeggen, Andreas; Dirnagl, Ulrich; Bradke, Frank; Volz, Magdalena S; DeVivo, Michael J; Chen, Yuying; von Andrian, Ulrich H; Schwab, Jan M
2017-11-01
Acute spinal cord injury (SCI) causes systemic immunosuppression and life-threatening infections, thought to result from noradrenergic overactivation and excess glucocorticoid release via hypothalamus-pituitary-adrenal axis stimulation. Instead of consecutive hypothalamus-pituitary-adrenal axis activation, we report that acute SCI in mice induced suppression of serum norepinephrine and concomitant increase in cortisol, despite suppressed adrenocorticotropic hormone, indicating primary (adrenal) hypercortisolism. This neurogenic effect was more pronounced after high-thoracic level (Th1) SCI disconnecting adrenal gland innervation, compared with low-thoracic level (Th9) SCI. Prophylactic adrenalectomy completely prevented SCI-induced glucocorticoid excess and lymphocyte depletion but did not prevent pneumonia. When adrenalectomized mice were transplanted with denervated adrenal glands to restore physiologic glucocorticoid levels, the animals were completely protected from pneumonia. These findings identify a maladaptive sympathetic-neuroendocrine adrenal reflex mediating immunosuppression after SCI, implying that therapeutic normalization of the glucocorticoid and catecholamine imbalance in SCI patients could be a strategy to prevent detrimental infections.
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Online support for individuals with spinal cord injuries: An ethnographic investigation
O'Riley, Alisa A.; Rose, Jon; Dalal, Brinda
2014-01-01
Background Although social support is an important protective factor for individuals with spinal cord injuries (SCIs), individuals often encounter significant barriers to obtaining support after experiencing a SCI. It has been suggested that the Internet may serve to help individuals with disabilities overcome common barriers in obtaining support, yet research examining the efficacy of Internet-based support for individuals with SCI has been mixed. Objective To develop a more nuanced understanding of how individuals with SCI can or might use the Internet for support. Design Using an ethnographic approach, we conducted semi-structured interviews with nine individuals with SCI to explore perceived needs and barriers to information-seeking and online support. Setting Participants were recruited from Veterans Administration medical center outpatient and inpatient units providing specialty care to individuals with SCIs and from a community SCI Center of Excellence. Results Individuals with SCI gain emotional, problem-focused, and reciprocal support from online sources. Conclusions Online resources can provide important opportunities for social support for individuals with SCI. PMID:24090378
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Manipulating the polar mismatch at the LaNi O 3 / SrTi O 3 (111) interface
DOE Office of Scientific and Technical Information (OSTI.GOV)
Saghayezhian, M.; Wang, Zhen; Guo, Hangwen
2017-04-20
Heteroepitaxial growth of transition-metal oxide films on the open (111) surface of SrTi O 3 results in significant restructuring due to the polar mismatch. Monitoring the structure and composition on an atomic scale of LaNi O 3 / SrTi O 3 (111) interface as a function of processing conditions has enabled the avoidance of the expected polar catastrophe. Using atomically resolved transmission electron microscopy and spectroscopy as well as low-energy electron diffraction, the structure of the thin film, from interface to the surface, has been studied. Here, we show that the proper processing can lead to a structure that ismore » ordered, coherent with the substrate without intermediate structural phase. Using angle-resolved x-ray photoemission spectroscopy we show that the oxygen content of thin films increases with the film thickness, which indicates that the polar mismatch is avoided by the presence of oxygen vacancies.« less
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Monge-Pereira, E; Casatorres Perez-Higueras, I; Fernandez-Gonzalez, P; Ibanez-Pereda, J; Serrano, J I; Molina-Rueda, F
2017-04-16
In the last years, new technologies such as the brain-machine interfaces (BMI) have been incorporated in the rehabilitation process of subjects with stroke. These systems are able to detect motion intention, analyzing the cortical signals using different techniques such as the electroencephalography (EEG). This information could guide different interfaces such as robotic devices, electrical stimulation or virtual reality. A 40 years-old man with stroke with two months from the injury participated in this study. We used a BMI based on EEG. The subject's motion intention was analyzed calculating the event-related desynchronization. The upper limb motor function was evaluated with the Fugl-Meyer Assessment and the participant's satisfaction was evaluated using the QUEST 2.0. The intervention using a physical therapist as an interface was carried out without difficulty. The BMI systems detect cortical changes in a subacute stroke subject. These changes are coherent with the evolution observed using the Fugl-Meyer Assessment.
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Passing waves from atomistic to continuum
NASA Astrophysics Data System (ADS)
Chen, Xiang; Diaz, Adrian; Xiong, Liming; McDowell, David L.; Chen, Youping
2018-02-01
Progress in the development of coupled atomistic-continuum methods for simulations of critical dynamic material behavior has been hampered by a spurious wave reflection problem at the atomistic-continuum interface. This problem is mainly caused by the difference in material descriptions between the atomistic and continuum models, which results in a mismatch in phonon dispersion relations. In this work, we introduce a new method based on atomistic dynamics of lattice coupled with a concurrent atomistic-continuum method to enable a full phonon representation in the continuum description. This permits the passage of short-wavelength, high-frequency phonon waves from the atomistic to continuum regions. The benchmark examples presented in this work demonstrate that the new scheme enables the passage of all allowable phonons through the atomistic-continuum interface; it also preserves the wave coherency and energy conservation after phonons transport across multiple atomistic-continuum interfaces. This work is the first step towards developing a concurrent atomistic-continuum simulation tool for non-equilibrium phonon-mediated thermal transport in materials with microstructural complexity.
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Interface module for transverse energy input to dye laser modules
English, R.E. Jr.; Johnson, S.A.
1994-10-11
An interface module for transverse energy input to dye laser modules is provided particularly for the purpose of delivering enhancing transverse energy beams in the form of illumination bar to the lasing zone of a dye laser device, in particular to a dye laser amplifier. The preferred interface module includes an optical fiber array having a plurality of optical fibers arrayed in a co-planar fashion with their distal ends receiving coherent laser energy from an enhancing laser source, and their proximal ends delivered into a relay structure. The proximal ends of the optical fibers are arrayed so as to be coplanar and to be aimed generally at a common point. The transverse energy beam array delivered from the optical fiber array is acted upon by an optical element array to produce an illumination bar which has a cross section in the form of a elongated rectangle at the position of the lasing window. The illumination bar is selected to have substantially uniform intensity throughout. 5 figs.
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Jang, Yeonsik; Kwon, Sung-Joo; Shin, Jaeho; Jeong, Hyunhak; Hwang, Wang-Taek; Kim, Junwoo; Koo, Jeongmin; Ko, Taeg Yeoung; Ryu, Sunmin; Wang, Gunuk; Lee, Tae-Woo; Lee, Takhee
2017-12-06
In this study, we fabricated and characterized vertical molecular junctions consisting of self-assembled monolayers of benzenedithiol (BDT) with a p-doped multilayer graphene electrode. The p-type doping of a graphene film was performed by treating pristine graphene (work function of ∼4.40 eV) with trifluoromethanesulfonic (TFMS) acid, producing a significantly increased work function (∼5.23 eV). The p-doped graphene-electrode molecular junctions statistically showed an order of magnitude higher current density and a lower charge injection barrier height than those of the pristine graphene-electrode molecular junctions, as a result of interface engineering. This enhancement is due to the increased work function of the TFMS-treated p-doped graphene electrode in the highest occupied molecular orbital-mediated tunneling molecular junctions. The validity of these results was proven by a theoretical analysis based on a coherent transport model that considers asymmetric couplings at the electrode-molecule interfaces.
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Grasmücke, Dennis; Zieriacks, Amrei; Jansen, Oliver; Fisahn, Christian; Sczesny-Kaiser, Matthias; Wessling, Martin; Meindl, Renate C; Schildhauer, Thomas A; Aach, Mirko
2017-05-01
Objective Age and lesion level are believed to represent outcome predictors in rehabilitation of patients with chronic spinal cord injury (SCI). The Hybrid Assistive Limb (HAL) exoskeleton enables patients to perform a voluntary controlled gait pattern via an electromyography-triggered neuromuscular feedback system, and has been introduced as a temporary gait training tool in patients with SCI. The aim of this prospective pre- and postintervention study was to examine functional outcomes as a function of age and lesion level in patients with chronic incomplete SCI (iSCI) or chronic complete SCI (cSCI) with zones of partial preservation (ZPP) by using the HAL as a temporary training tool. Methods Fifty-five participants with chronic iSCI or cSCI (mean time since injury 6.85 ± 5.12 years) were classified according to the American Spinal Injury Association (ASIA) Impairment Scale (AIS) and divided by age (< 50 or ≥ 50 years), independent of lesion level, and also into 4 homogeneous groups according to lesion level. The subgroups were as follows: Subgroup 1, tetraplegic iSCI (n = 13) (C2-8, AIS C [n = 8] and AIS D [n = 5]); Subgroup 2, paraplegic iSCI with spastic motor behavior (n = 15) (T2-12, AIS C [n = 8] and AIS D [n = 7]); Subgroup 3, paraplegic cSCI with complete motor paraplegia and absence of spastic motor behavior (n = 18) (T11-L4 [AIS A], and ZPP from L-3 to S-1); and Subgroup 4, paraplegic iSCI with absence of spastic motor behavior (n = 9) (T12-L3, AIS C [n = 8] and AIS D [n = 1]). The training paradigm consisted of 12 weeks of HAL-assisted treadmill training (5 times/week). Baseline status was documented prior to intervention by using the AIS grade, Walking Index for SCI II (WISCI II) score, the 10-meter walk test (10MWT), and the 6-minute walk test (6MinWT). Training effects were assessed after 6 and 12 weeks of therapy, without HAL assistance. Results Overall, a time reduction of 47% in the 10MWT, self-selected speed (10MWTsss) (< 50 years = 56% vs ≥ 50 years = 37%) and an increase of 50% in the 6MinWT were documented. The WISCI II scores showed a mean gain of 1.69 levels. At the end of the study, 24 of 55 patients (43.6%) were less dependent on walking aids. Age had a nonsignificant negative influence on the 10MWTsss. Despite a few nonsignificant subgroup differences, participants improved across all tests. Namely, patients with iSCI who had spastic motor behavior improved to a nonsignificant, lesser extent in the 6MinWT. Conclusions The HAL-assisted treadmill training leads to functional improvements in chronic iSCI or cSCI, both in and out of the exoskeleton. An improvement of approximately 50% in the 10MWTsss and in gait endurance (6MinWT) can be expected from such training. The influences of SCI lesion level and age on functional outcome were nonsignificant in the present study. Older age (≥ 50 years) may be associated with smaller improvements in the 10MWTsss. An iSCI in paraplegic patients with spastic motor behavior may be a nonsignificant negative predictor in gait endurance improvements. Clinical trial registration no.: DRKS00010250 ( https://drks-neu.uniklinik-freiburg.de/drks_web/setLocale_DE.do ).