Self-consistent full-potential linearized-augmented-plane-wave local-density electronic-structure studies of magnetism and superconductivity in C15 compounds: ZrZn/sub 2/ and ZrV/sub 2/

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, M.; Jansen, H.J.F.; Freeman, A.J.

The electronic structure and properties of the cubic Laves phase (C15) compounds ZrZn/sub 2/ and ZrV/sub 2/ have been determined using our all-electron full-potential linearized-augmented-plane-wave (FLAPW) method for bulk solids. The computations were performed in two stages: (i) self-consistent warped muffin tin and (ii) self-consistent full potential. Spin-orbit coupling was included after either stage. The effects of the inclusion of the nonspherical terms inside the muffin tins on the eigenvalues is found to be small (of order 1 mRy). However, due to the fact that some of the bands near the Fermi level are flat, this effect leads to amore » much higher value of the density of states at E/sub F/ in ZnZr/sub 2/. The most important difference between the materials ZrZn/sub 2/ and ZrV/sub 2/ is the position of the d bands derived from the Zr and V atoms. Consequently, these materials have completely different Fermi surfaces. We have investigated the magnetic properties of these compounds by evaluating their generalized Stoner factors and found agreement with experiment. Our results for the superconducting transition temperature for these materials is found to be strongly dependent on the spin fluctuation parameter ..mu../sub sp/. Of course, because of the magnetic transition, superconductivity cannot be observed in ZnZr/sub 2/.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Verma, U. P.; Nayak, V.

Quantum mechanical first principle calculations have been performed to study the electronic and structural properties of TiN and TiAs in zinc blende (ZB) and rock salt (RS) structures. The full-potential linearized augmented plane wave (FP-LAPW) method has been used within the framework of density functional theory (DFT). The exchange correlation functional has been solved employing generalized gradient approximation (GGA). Our predicted results for lattice constants are in good agreement with the earlier findings. The electronic band structures of TiX are metallic in both the phases.

First-principles study of structural stability, electronic, optical and elastic properties of binary intermetallic: PtZr

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pagare, Gitanjali, E-mail: gita-pagare@yahoo.co.in; Jain, Ekta, E-mail: jainekta05@gmail.com; Sanyal, S. P., E-mail: sps.physicsbu@gmail.com

2016-05-06

Structural, electronic, optical and elastic properties of PtZr have been studied using the full-potential linearized augmented plane wave (FP-LAPW) method within density functional theory (DFT). The energy against volume and enthalpy vs. pressure variation in three different structures i.e. B{sub 1}, B{sub 2} and B{sub 3} for PtZr has been presented. The equilibrium lattice parameter, bulk modulus and its pressure derivative have been obtained using optimization method for all the three phases. Furthermore, electronic structure was discussed to reveal the metallic character of the present compound. The linear optical properties are also studied under zero pressure for the first time.more » Results on elastic properties are obtained using generalized gradient approximation (GGA) for exchange correlation potentials. Ductile nature of PtZr compound is predicted in accordance with Pugh’s criteria.« less

Chemical Potential Evaluation of Thermoelectric and Mechanical Properties of Zr2CoZ (Z = Si, Ge) Heusler Alloys

NASA Astrophysics Data System (ADS)

Yousuf, Saleem; Gupta, Dinesh C.

2018-04-01

The electronic, mechanical and thermoelectric properties of Zr2CoZ (Z = Si, Ge) Heusler alloys are investigated by the full-potential linearized augmented plane wave method. Using the Voigt-Reuss approximation, we calculated the various elastic constants, the shear and Young's moduli, and Poisson's ratio which predict the ductile nature of the alloys. Thermoelectric coefficients viz., Seebeck, electrical conductivity and figure of merit show Zr2CoZ alloys as n-type thermoelectric materials showing a linearly increasing Seebeck coefficient with temperature mainly because of the existence of almost flat conduction bands along L to D directions of a high symmetry Brillouin zone. The efficiency of conversion was measured as the figure of merit by taking into effect the lattice thermal part that achieves an upper-limit of 0.14 at 1200 K which may favour their use for waste heat recovery at higher temperatures.

Public Interest in Breast Augmentation: Analysis and Implications of Google Trends Data.

PubMed

Wilson, Stelios C; Daar, David A; Sinno, Sammy; Levine, Steven M

2018-06-01

Breast augmentation is the most common aesthetic surgery performed in the United States (US) annually. Analysis of Google Trends (GT) data may give plastic surgeons useful information regarding worldwide, national, and regional interest for breast augmentation and other commonly performed aesthetic surgeries. Data were collected using GT for breast augmentation and associated search terms from January 2004 to May 2017. Case volume was obtained from the American Society of Plastic Surgeons (ASPS) annual reports for the calendar year 2005-2016. Trend analysis showed that total search term volume for breast augmentation and breast implants gradually decreased worldwide and in the US over the study period while the search term boob job slowly increased. Univariate linear regression demonstrated a statistically significant positive correlation between average annual Google search volume of "breast augmentation" and the annual volume of breast augmentations performed in the US according to ASPS data (R 2  = 0.44, p = 0.018). There was no significant correlation between national volume of breast augmentations performed and search volume using the terms "breast implants" or "boob job" over time (p = 0.84 and p = 0.07, respectively). In addition, there appears to be country specific variation in interest based on time of year and peaks in interest following specific policies. To our knowledge, this is the first and only analysis of GT data in the plastic surgery literature to date. To that end, this study highlights this large and potentially powerful data set for plastic surgeons both in the US and around the world. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Electron-positron momentum density in Tl 2Ba 2CuO 6

NASA Astrophysics Data System (ADS)

Barbiellini, B.; Gauthier, M.; Hoffmann, L.; Jarlborg, T.; Manuel, A. A.; Massidda, S.; Peter, M.; Triscone, G.

1994-08-01

We present calculations of the electron-positron momentum density for the high- Tc superconductor Tl 2Ba 2CuO 6, together with some preliminary two-dimensional angular correlation of the annihilation radiation (2D-ACAR) measurements. The calculations are based on the first-principles electronic structure obtained using the full-potential linearized augmented plane wave (FLAPW) and the linear muffin-tin orbital (LMTO) methods. We also use a linear combination of the atomic orbitals-molecular orbital method (LCAO-MO) to discuss orbital contributions to the anisotropies. Some agreement between calculated and measured 2D-ACAR anisotropies encourage sample improvement for further Fermi surface investigations. Indeed, our results indicate a non-negligle overlap of the positron wave function with the CuOo 2 plane electrons. Therefore, this compound may be well suited for investigating the relevant CuO 2 Fermi surface by 2D-ACAR.

Density functional theory calculations of III-N based semiconductors with mBJLDA

NASA Astrophysics Data System (ADS)

Gürel, Hikmet Hakan; Akıncı, Özden; Ünlü, Hilmi

2017-02-01

In this work, we present first principles calculations based on a full potential linear augmented plane-wave method (FP-LAPW) to calculate structural and electronic properties of III-V based nitrides such as GaN, AlN, InN in a zinc-blende cubic structure. First principles calculation using the local density approximation (LDA) and generalized gradient approximation (GGA) underestimate the band gap. We proposed a new potential called modified Becke-Johnson local density approximation (MBJLDA) that combines modified Becke-Johnson exchange potential and the LDA correlation potential to get better band gap results compared to experiment. We compared various exchange-correlation potentials (LSDA, GGA, HSE, and MBJLDA) to determine band gaps and structural properties of semiconductors. We show that using MBJLDA density potential gives a better agreement with experimental data for band gaps III-V nitrides based semiconductors.

Engine Yaw Augmentation for Hybrid-Wing-Body Aircraft via Optimal Control Allocation Techniques

NASA Technical Reports Server (NTRS)

Taylor, Brian R.; Yoo, Seung Yeun

2011-01-01

Asymmetric engine thrust was implemented in a hybrid-wing-body non-linear simulation to reduce the amount of aerodynamic surface deflection required for yaw stability and control. Hybrid-wing-body aircraft are especially susceptible to yaw surface deflection due to their decreased bare airframe yaw stability resulting from the lack of a large vertical tail aft of the center of gravity. Reduced surface deflection, especially for trim during cruise flight, could reduce the fuel consumption of future aircraft. Designed as an add-on, optimal control allocation techniques were used to create a control law that tracks total thrust and yaw moment commands with an emphasis on not degrading the baseline system. Implementation of engine yaw augmentation is shown and feasibility is demonstrated in simulation with a potential drag reduction of 2 to 4 percent. Future flight tests are planned to demonstrate feasibility in a flight environment.

Cd in SnO: Probing structural effects on the electronic structure of doped oxide semiconductors through the electric field gradient at the Cd nucleus

NASA Astrophysics Data System (ADS)

Errico, Leonardo A.; Rentería, Mario; Petrilli, Helena M.

2007-04-01

We perform an ab initio study of the electric field gradient (EFG) at the nucleus of Cd impurities at substitutional Sn sites in crystalline SnO. The full-potential linearized-augmented plane wave and the projector augmented wave methods used here allow us to treat the electronic structure of the doped system and the atomic relaxations introduced by the impurities in the host in a fully self-consistent way using a supercell approach in a state-of-the-art way. Effects of the impurity charge state on the electronic and structural properties are also discussed. Since the EFG is a very subtle quantity, its determination is very useful to probe ground-state properties such as the charge density. We show that the EFG is very sensitive to structural relaxations induced by the impurity. Our theoretical predictions are compared with available experimental results.

A GPS Phase-Locked Loop Performance Metric Based on the Phase Discriminator Output

PubMed Central

Stevanovic, Stefan; Pervan, Boris

2018-01-01

We propose a novel GPS phase-lock loop (PLL) performance metric based on the standard deviation of tracking error (defined as the discriminator’s estimate of the true phase error), and explain its advantages over the popular phase jitter metric using theory, numerical simulation, and experimental results. We derive an augmented GPS phase-lock loop (PLL) linear model, which includes the effect of coherent averaging, to be used in conjunction with this proposed metric. The augmented linear model allows more accurate calculation of tracking error standard deviation in the presence of additive white Gaussian noise (AWGN) as compared to traditional linear models. The standard deviation of tracking error, with a threshold corresponding to half of the arctangent discriminator pull-in region, is shown to be a more reliable/robust measure of PLL performance under interference conditions than the phase jitter metric. In addition, the augmented linear model is shown to be valid up until this threshold, which facilitates efficient performance prediction, so that time-consuming direct simulations and costly experimental testing can be reserved for PLL designs that are much more likely to be successful. The effect of varying receiver reference oscillator quality on the tracking error metric is also considered. PMID:29351250

Flight Test of Composite Model Reference Adaptive Control (CMRAC) Augmentation Using NASA AirSTAR Infrastructure

NASA Technical Reports Server (NTRS)

Gregory, Irene M.; Gadient, ROss; Lavretsky, Eugene

2011-01-01

This paper presents flight test results of a robust linear baseline controller with and without composite adaptive control augmentation. The flight testing was conducted using the NASA Generic Transport Model as part of the Airborne Subscale Transport Aircraft Research system at NASA Langley Research Center.

Central arterial stiffness is associated with systemic inflammation among Asians with type 2 diabetes.

PubMed

Zhang, Xiao; Liu, Jian Jun; Fang Sum, Chee; Ying, Yeoh Lee; Tavintharan, Subramaniam; Ng, Xiao Wei; Su, Chang; Low, Serena; Lee, Simon Bm; Tang, Wern Ee; Lim, Su Chi

2016-07-01

To examine the relationship between inflammation and central arterial stiffness in a type 2 diabetes Asian cohort. Central arterial stiffness was estimated by carotid-femoral pulse wave velocity and augmentation index. Linear regression model was used to evaluate the association of high-sensitivity C-reactive protein and soluble receptor for advanced glycation end products with pulse wave velocity and augmentation index. High-sensitivity C-reactive protein was analysed as a continuous variable and categories (<1, 1-3, and >3 mg/L). There is no association between high-sensitivity C-reactive protein and pulse wave velocity. Augmentation index increased with high-sensitivity C-reactive protein as a continuous variable (β = 0.328, p = 0.049) and categories (β = 1.474, p = 0.008 for high-sensitivity C-reactive protein: 1-3 mg/L and β = 1.323, p = 0.019 for high-sensitivity C-reactive protein: >3 mg/L) after multivariable adjustment. No association was observed between augmentation index and soluble receptor for advanced glycation end products. Each unit increase in natural log-transformed soluble receptor for advanced glycation end products was associated with 0.328 m/s decrease in pulse wave velocity after multivariable adjustment (p = 0.007). Elevated high-sensitivity C-reactive protein and decreased soluble receptor for advanced glycation end products are associated with augmentation index and pulse wave velocity, respectively, suggesting the potential role of systemic inflammation in the pathogenesis of central arterial stiffness in type 2 diabetes. © The Author(s) 2016.

Electronic, thermoelectric and transport properties of cesium cadmium trifluoride: A DFT study

NASA Astrophysics Data System (ADS)

Abraham, Jisha Annie; Pagare, G.; Sanyal, Sankar P.

2018-04-01

The full potential linearized augmented plane wave method based on density functional theory is employed to investigate the electronic structure of CsCdF3. The electronic properties of this compound have been studied from the band structure plot and density of states. The presence of indirect energy gap reveals its insulating nature. Using constant relaxation time, the electrical conductivity, electronic thermal conductivity, Seebeck coefficient and figure of merit are calculated by using Boltzmann transport theory. We have also studied the temperature dependence of thermoelectric properties of this compound.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zuo, Zhiqi

The Full Potential Linear Augmented Plane Wave (FPLAPW or FLAPW) method is used for a spin-polarized band calculation for ordered Fe 3Pt. As major purpose, the momentum distributions of the spin-polarized electrons are calculated and compared with results from a magnetic Compton scattering measurement. To get related information, the electronic behavior is also analyzed by examining the partial densities of states and the spatial electron distributions; the role of alloying effects is then explored by studying the electrons in some related alloys: Fe 3Ni, Fe 3Pd, Ni 3Pt and Co 3Pt.

Introducing Stochastic Simulation of Chemical Reactions Using the Gillespie Algorithm and MATLAB: Revisited and Augmented

ERIC Educational Resources Information Center

Argoti, A.; Fan, L. T.; Cruz, J.; Chou, S. T.

2008-01-01

The stochastic simulation of chemical reactions, specifically, a simple reversible chemical reaction obeying the first-order, i.e., linear, rate law, has been presented by Martinez-Urreaga and his collaborators in this journal. The current contribution is intended to complement and augment their work in two aspects. First, the simple reversible…

Microhartree precision in density functional theory calculations

NASA Astrophysics Data System (ADS)

Gulans, Andris; Kozhevnikov, Anton; Draxl, Claudia

2018-04-01

To address ultimate precision in density functional theory calculations we employ the full-potential linearized augmented plane-wave + local-orbital (LAPW + lo) method and justify its usage as a benchmark method. LAPW + lo and two completely unrelated numerical approaches, the multiresolution analysis (MRA) and the linear combination of atomic orbitals, yield total energies of atoms with mean deviations of 0.9 and 0.2 μ Ha , respectively. Spectacular agreement with the MRA is reached also for total and atomization energies of the G2-1 set consisting of 55 molecules. With the example of α iron we demonstrate the capability of LAPW + lo to reach μ Ha /atom precision also for periodic systems, which allows also for the distinction between the numerical precision and the accuracy of a given functional.

Role of modified Becke-Johnson potential in computation of electronic and optical properties of mixed crystals CdxZn1-xSe

NASA Astrophysics Data System (ADS)

Talreja, Sonal; Ahuja, B. L.

2015-08-01

Electronic and optical properties of CdxZn1-xSe (x = 0, 0.25, 0.5, 0.75, 1) compounds are investigated using the first-principles full potential linearized augmented plane wave method. In particular, we have used modified version of the exchange potential of Becke and Johnson, so called mBJ potential. We have discussed the energy bands, density of states, and optical properties such as dielectric constants, refractive indices, reflection spectra, extinction coefficients of all the CdxZn1-xSe compounds. Our mBJ potential based data are found to be in excellent agreement with the available experimental data, which unambiguously validates the applicability of orbital independent exchange-correlation potential in mixed semiconductor crystals. The optical properties are discussed in terms of applicability of Cd-Zn-Se system in light-emitting diodes, UV detectors and filters, etc.

Potential Use of Augmented Reality in LIS Education

ERIC Educational Resources Information Center

Wójcik, Magdalena

2016-01-01

The subject of this article is the use of augmented reality technology in library and information science education. The aim is to determine the scope and potential uses of augmented reality in the education of information professionals. In order to determine the scope and forms of potential use of AR technology in LIS education a two-step…

An accelerated proximal augmented Lagrangian method and its application in compressive sensing.

PubMed

Sun, Min; Liu, Jing

2017-01-01

As a first-order method, the augmented Lagrangian method (ALM) is a benchmark solver for linearly constrained convex programming, and in practice some semi-definite proximal terms are often added to its primal variable's subproblem to make it more implementable. In this paper, we propose an accelerated PALM with indefinite proximal regularization (PALM-IPR) for convex programming with linear constraints, which generalizes the proximal terms from semi-definite to indefinite. Under mild assumptions, we establish the worst-case [Formula: see text] convergence rate of PALM-IPR in a non-ergodic sense. Finally, numerical results show that our new method is feasible and efficient for solving compressive sensing.

First-principles study of structural, electronic, linear and nonlinear optical properties of Ga{2}PSb ternary chalcopyrite

NASA Astrophysics Data System (ADS)

Ouahrani, T.; Reshak, A. H.; de La Roza, A. Otero; Mebrouki, M.; Luaña, V.; Khenata, R.; Amrani, B.

2009-12-01

We report results from first-principles density functional calculations using the full-potential linear augmented plane wave (FP-LAPW) method. The generalized gradient approximation (GGA) and the Engel-Vosko-generalized gradient approximation (EV-GGA) were used for the exchange-correlation energy of the structural, electronic, linear and nonlinear optical properties of the chalcopyrite Ga2PSb compound. The valence band maximum (VBM) is located at the Γv point, and the conduction band minimum (CBM) is located at the Γc point, resulting in a direct band gap of about 0.365 eV for GGA and 0.83 eV for EV-GGA. In comparison with the experimental one (1.2 eV) we found that EV-GGA calculation gives energy gap in reasonable agreement with the experiment. The spin orbit coupling has marginal influence on the optical properties. The ground state quantities such as lattice parameters (a, c and u), bulk modules B and its pressure derivative B^primeare evaluated.

Electroosmosis of viscoelastic fluids over charge modulated surfaces in narrow confinements

NASA Astrophysics Data System (ADS)

Ghosh, Uddipta; Chakraborty, Suman

2015-06-01

In the present work, we attempt to analyze the electroosmotic flow of a viscoelastic fluid, following quasi-linear constitutive behavior, over charge modulated surfaces in narrow confinements. We obtain analytical solutions for the flow field for thin electrical double layer (EDL) limit through asymptotic analysis for small Deborah numbers. We show that a combination of matched and regular asymptotic expansion is needed for the thin EDL limit. We subsequently determine the modified Smoluchowski slip velocity for viscoelastic fluids and show that the quasi-linear nature of the constitutive behavior adds to the periodicity of the flow. We also obtain the net throughput in the channel and demonstrate its relative decrement as compared to that of a Newtonian fluid. Our results may have potential implications towards augmenting microfluidic mixing by exploiting electrokinetic transport of viscoelastic fluids over charge modulated surfaces.

Electronic structures of of PuX (X=S, Se, Te)

NASA Astrophysics Data System (ADS)

Maehira, Takahiro; Sakai, Eijiro; Tatetsu, Yasutomi

2013-08-01

We have calculated the energy band structures and the Fermi surfaces of PuS, PuSe, and PuTe by using a self-consistent relativistic linear augmented-plane-wave method with the exchange and correlation potential in the local density approximation. In general, the energy bands near the Fermi level are mainly caused by the hybridization between the Pu 5 f and the monochalcogenide p electrons. The obtained main Fermi surfaces consisted of two hole sheets and one electron sheet, which were constructed from the band having both the Pu 5 f state and the monochalcogenide p state.

Ab-initio investigations for opto-electronic response of (Cd, Zn)Ga2Te4: Promising solar PV materials

NASA Astrophysics Data System (ADS)

Sahariya, Jagrati; Soni, Amit; Kumar, Pancham

2018-04-01

In this paper, the first principle calculations are performed to analyze the structural, electronic and optical behavior of promising solar materials (Cd,Zn)Ga2Te4. To perform these calculations we have used one of the most accurate Full Potential Linearized Augmented Plane Wave (FP-LAPW) method. The ground state properties of these compounds are confirmed over here after proper examination of energy and charge convergence using Perdew-Burke-Ernzerhof (PBE-sol) exchange correlation potential. The investigations performed such as energy band structure, Density of States (DOS), optical parameters like complex dielectric function and absorption co-efficient are discussed over here to understand the overall response of the chosen system.

Movement augmentation to evaluate human control of locomotor stability.

PubMed

Brown, Geoffrey; Wu, Mengnan Mary; Huang, Felix C; Gordon, Keith E

2017-07-01

Controlling center of mass (COM) position and velocity within a dynamic base of support is essential for gait stability. This skill is often compromised following neurologic injury, creating a need to develop effective interventions to enhance gait stability. A movement augmentation paradigm applied to walking could potentially be used to improve control of COM dynamics. We have developed a cable robot system, the Agility Trainer, to apply continuous frontal-plane forces to the pelvis during treadmill walking. This cable robot system uses a set of series elastic actuators powered by linear motors to create bilateral forces. Here we use the Agility Trainer to create a negative viscosity force field proportional to the subject's lateral velocity. Two healthy young subjects performed two 10-minute walking trials, Baseline and Negative Viscosity. During the first minute of walking in the Negative Viscosity field, participants' lateral COM motion became less controlled when compared to the rhythmic sinusoidal motion observed during Baseline walking. By the 10th minute of walking in the Negative Viscosity field the participants had adapted their gait patterns, decreasing their variation in peak lateral COM speed each stride. These results demonstrate that it is feasible to use the Agility Trainer to apply a movement augmentation paradigm to human walking.

Transfer Alignment Error Compensator Design Based on Robust State Estimation

NASA Astrophysics Data System (ADS)

Lyou, Joon; Lim, You-Chol

This paper examines the transfer alignment problem of the StrapDown Inertial Navigation System (SDINS), which is subject to the ship’s roll and pitch. Major error sources for velocity and attitude matching are lever arm effect, measurement time delay and ship-body flexure. To reduce these alignment errors, an error compensation method based on state augmentation and robust state estimation is devised. A linearized error model for the velocity and attitude matching transfer alignment system is derived first by linearizing the nonlinear measurement equation with respect to its time delay and dominant Y-axis flexure, and by augmenting the delay state and flexure state into conventional linear state equations. Then an H∞ filter is introduced to account for modeling uncertainties of time delay and the ship-body flexure. The simulation results show that this method considerably decreases azimuth alignment errors considerably.

Cooperative global optimal preview tracking control of linear multi-agent systems: an internal model approach

NASA Astrophysics Data System (ADS)

Lu, Yanrong; Liao, Fucheng; Deng, Jiamei; Liu, Huiyang

2017-09-01

This paper investigates the cooperative global optimal preview tracking problem of linear multi-agent systems under the assumption that the output of a leader is a previewable periodic signal and the topology graph contains a directed spanning tree. First, a type of distributed internal model is introduced, and the cooperative preview tracking problem is converted to a global optimal regulation problem of an augmented system. Second, an optimal controller, which can guarantee the asymptotic stability of the augmented system, is obtained by means of the standard linear quadratic optimal preview control theory. Third, on the basis of proving the existence conditions of the controller, sufficient conditions are given for the original problem to be solvable, meanwhile a cooperative global optimal controller with error integral and preview compensation is derived. Finally, the validity of theoretical results is demonstrated by a numerical simulation.

Full-Potential Calculation of Structural, Electronic, and Thermodynamic Properties of Fluoroperovskite { CsMF}3 (M = Be and Mg)

NASA Astrophysics Data System (ADS)

Harmel, M.; Khachai, H.; Ameri, A.; Baki, N.; Haddou, A.; Khalfa, M.; Abbar, B.; Omran, S. Bin; Uğur, G.; Uğur, Ş.; Khenata, R.

2012-12-01

The structural and electronic properties of the cubic fluoroperoveskite { CsBeF}3 and { CsMgF}3 have been investigated using the full-potential-linearized augmented plane wave method within the density functional theory. The exchange-correlation potential was treated with the local density approximation and the generalized gradient approximation. The calculations of the electronic band structures show that { CsBeF}_{3 } has an indirect bandgap, whereas { CsMgF}3 has a direct bandgap. Through the quasi-harmonic Debye model, in which the phononic effects are considered, the effect of pressure P and temperature T on the lattice parameter, bulk modulus, thermal expansion coefficient, Debye temperature, and the heat capacity for { CsBeF}3 and { CsMgF}3 compounds are investigated for the first time.

Ab-initio calculations of structural, electronic, and optical properties of Zn3(VO4)2

NASA Astrophysics Data System (ADS)

Ahmed, Nisar; Mukhtar, S.; Gao, Wei; Zafar Ilyas, Syed

2018-03-01

The structural, electronic, and optical properties of Zn3(VO4)2 are investigated using full potential linearized augmented plane wave (FP-LAPW) method within the framework of density functional theory (DFT). Various approaches are adopted to treat the exchange and correlation potential energy such as generalized gradient approximation (GGA), GGA+U, and the Tran–Blaha modified Becke–Johnson (TB-mBJ) potential. The calculated band gap of 3.424 eV by TB-mBJ is found to be close to the experimental result (3.3 eV). The optical anisotropy is analyzed through optical constants, such as dielectric function and absorption coefficient along parallel and perpendicular crystal orientations. The absorption coefficient reveals high absorption (1.5× {10}6 {cm}}-1) of photons in the ultraviolet region.

Boron doped GaN and InN: Potential candidates for spintronics

NASA Astrophysics Data System (ADS)

Fan, S. W.; Huang, X. N.; Yao, K. L.

2017-02-01

The full potential linearized augmented plane wave method together with the Tran-Blaha modified Becke-Johnson potential is utilized to investigate the electronic structures and magnetism for boron doped GaN and InN. Calculations show the boron substituting nitrogen (BN defects) could induce the GaN and InN to be half-metallic ferromagnets. The magnetic moments mainly come from the BN defects, and each BN defect would produce the 2.00 μB total magnetic moment. The electronic structures indicate the carriers-mediated double exchange interaction plays a crucial role in forming the ferromagnetism. Positive chemical pair interactions imply the BN defects would form the homogeneous distribution in GaN and InN matrix. Moderate formation energies suggest that GaN and InN with BN defects could be fabricated experimentally.

Residual mode correction in calibrating nonlinear damper for vibration control of flexible structures

NASA Astrophysics Data System (ADS)

Sun, Limin; Chen, Lin

2017-10-01

Residual mode correction is found crucial in calibrating linear resonant absorbers for flexible structures. The classic modal representation augmented with stiffness and inertia correction terms accounting for non-resonant modes improves the calibration accuracy and meanwhile avoids complex modal analysis of the full system. This paper explores the augmented modal representation in calibrating control devices with nonlinearity, by studying a taut cable attached with a general viscous damper and its Equivalent Dynamic Systems (EDSs), i.e. the augmented modal representations connected to the same damper. As nonlinearity is concerned, Frequency Response Functions (FRFs) of the EDSs are investigated in detail for parameter calibration, using the harmonic balance method in combination with numerical continuation. The FRFs of the EDSs and corresponding calibration results are then compared with those of the full system documented in the literature for varied structural modes, damper locations and nonlinearity. General agreement is found and in particular the EDS with both stiffness and inertia corrections (quasi-dynamic correction) performs best among available approximate methods. This indicates that the augmented modal representation although derived from linear cases is applicable to a relatively wide range of damper nonlinearity. Calibration of nonlinear devices by this means still requires numerical analysis while the efficiency is largely improved owing to the system order reduction.

A novel pressure variation study on electronic structure, mechanical stability and thermodynamic properties of potassium based fluoroperovskite

NASA Astrophysics Data System (ADS)

Erum, Nazia; Azhar Iqbal, Muhammad

2017-09-01

The effect of pressure variation on stability, structural parameters, elastic constants, mechanical, electronic and thermodynamic properties of cubic SrKF3 fluoroperovskite have been investigated by using the full-potential linearized augmented plane wave (FP-LAPW) method combined with Quasi-harmonic Debye model in which the phonon effects are considered. The calculated lattice parameters show a prominent decrease in lattice constant and bonds length with the increase in pressure. The application of pressure from 0 to 25 GPa reveals a predominant characteristic associated with widening of bandgap with GGA and GGA plus Tran-Blaha modified Becke-Johnson (TB-mBJ) potential. The influence of pressure on elastic constants and their related mechanical parameters have been discussed in detail. Apart of linear dependence of elastic coefficients, transition from brittle to ductile behavior is also observed at elevated pressure ranges. We have successfully computed variation of lattice constant, volume expansion, bulk modulus, Debye temperature and specific heat capacities at pressure and temperature in the range of 0-25 GPa and 0-600 K.

Influence of the local-spin-density correlation functional on the stability of bcc ferromagnetic iron

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, D.; Clougherty, D.P.; MacLaren, J.M.

1991-10-01

The influence of local-spin-dependent correlation effects on the predicted stable ground-state phase of iron is reexamined with use of general-potential linearized augmented-plane-wave calculations. Differences in the form of the Vosko-Wilk-Nusair (VWN) local-spin-density functional used in previous studies are noted, since in previous studies significant additional approximations were made with respect to those of Vosko, Wilk, and Nusan (Can. J. Phys. 58, 1200 (1980)) and of MacLaren, Clougherty, and Albers (Phys. Rev. B 42, 3205 (1990)). While the results of previous linear muffin-tin orbital calculations using the VWN functional predict a bcc ferromagnetic ground state, the present calculations show that themore » VWN spin-correlation effects fail to stabilize a bcc ground state. Considerable sensitivity to the form of the spin interpolation is found.« less

Parallelization of the FLAPW method

NASA Astrophysics Data System (ADS)

Canning, A.; Mannstadt, W.; Freeman, A. J.

2000-08-01

The FLAPW (full-potential linearized-augmented plane-wave) method is one of the most accurate first-principles methods for determining structural, electronic and magnetic properties of crystals and surfaces. Until the present work, the FLAPW method has been limited to systems of less than about a hundred atoms due to the lack of an efficient parallel implementation to exploit the power and memory of parallel computers. In this work, we present an efficient parallelization of the method by division among the processors of the plane-wave components for each state. The code is also optimized for RISC (reduced instruction set computer) architectures, such as those found on most parallel computers, making full use of BLAS (basic linear algebra subprograms) wherever possible. Scaling results are presented for systems of up to 686 silicon atoms and 343 palladium atoms per unit cell, running on up to 512 processors on a CRAY T3E parallel supercomputer.

Central excitability contributes to supramaximal volitional contractions in human incomplete spinal cord injury

PubMed Central

Thompson, Christopher K; Lewek, Michael D; Jayaraman, Arun; Hornby, T George

2011-01-01

Abstract Despite greater muscle fatigue in individuals with spinal cord injury (SCI) when compared to neurologically intact subjects using neuromuscular electrical stimulation (NMES) protocols, few studies have investigated the extent of volitional fatigue in motor incomplete SCI. Using an established protocol of 20 repeated, intermittent, maximal volitional effort (MVE) contractions, we previously demonstrated that subjects with incomplete SCI unexpectedly demonstrated a 15% increase in peak knee extensor torques within the first five MVEs with minimal evidence of fatigue after 20 contraction. In the present study, we investigated potential segmental mechanisms underlying this supramaximal torque generation. Changes in twitch properties and maximum compound muscle action potentials (M-waves) were assessed prior to and following one, three and five MVEs, revealing a significant 17% increase only in maximum twitch torques after a single MVE. Despite this post-activation potentiation of the muscle, use of conventional NMES protocols to elicit repeated muscular contractions resulted in a significant decrease in evoked torque generation, suggesting limited the muscular contributions to the observed phenomenon. To evaluate potential central mechanisms underlying the augmented torques, non-linear responses to wide-pulse width (1 ms), low-intensity, variable-frequency (25–100 Hz) NMES were also tested prior to and following repeated MVEs. When variable-frequency NMES was applied following the repeated MVEs, augmented and prolonged torques were observed and accompanied by sustained quadriceps electromyographic activity often lasting >2s after stimulus termination. Such data suggest a potential contribution of elevated spinal excitability to the reserve in volitional force generation in incomplete SCI. PMID:21610138

Potential perils of peri-Pokémon perambulation: the dark reality of augmented reality?

PubMed Central

Joseph, Bellal; Armstrong, David G.

2016-01-01

Recently, the layering of augmented reality information on top of smartphone applications has created unprecedented user engagement and popularity. One augmented reality-based entertainment application, Pokémon Go (Pokémon Company, Tokyo, Japan) has become the most rapidly downloaded in history. This technology holds tremendous promise to promote ambulatory activity. However, there exists the obvious potential for distraction-related morbidity. We report two cases, presenting simultaneously to our trauma center, with injuries sustained secondary to gameplay with this augmented reality-based application. PMID:27713831

Potential perils of peri-Pokémon perambulation: the dark reality of augmented reality?

PubMed

Joseph, Bellal; Armstrong, David G

2016-10-01

Recently, the layering of augmented reality information on top of smartphone applications has created unprecedented user engagement and popularity. One augmented reality-based entertainment application, Pokémon Go (Pokémon Company, Tokyo, Japan) has become the most rapidly downloaded in history. This technology holds tremendous promise to promote ambulatory activity. However, there exists the obvious potential for distraction-related morbidity. We report two cases, presenting simultaneously to our trauma center, with injuries sustained secondary to gameplay with this augmented reality-based application.

Structural, electronic, magnetic and thermodynamic properties of Ni1-xTixO alloys an ab initio calculation and Monte Carlo study

NASA Astrophysics Data System (ADS)

Klaa, K.; Labidi, S.; Masrour, R.; Jabar, A.; Labidi, M.; Amara, A.; Drici, A.; Hlil, E. K.; Ellouze, M.

2018-06-01

Structural, electronic, magnetic and thermodynamic main features for Ni1-xTixO ternary alloys in rock-salt structure with Ti content in the range ? were studied using the full potential Linearized augmented plane wave (FP-LAPW) method within density functional theory. The exchange-correlation potential was calculated by the generalized gradient approximation. The analysis of the electronic density of states curves allowed the computation of the magnetic moments which are considered to lie along (010) axes. The thermodynamic stability of this alloy was investigated by calculating the excess enthalpy of mixing ? as well as the phase diagram. In addition, the Monte Carlo simulations have been exploited to calculate the transition temperature and magnetic coercive field in the alloy.

Electronic structures of Plutonium compounds with the NaCl-type monochalcogenides structure

NASA Astrophysics Data System (ADS)

Maehira, Takahiro; Tatetsu, Yasutomi

2012-12-01

We calculate the energy band structure and the Fermi surface of PuS, PuSe and PuTe by using a self-consistent relativistic linear augmented-plane-wave method with the exchange and correlation potential in a local density approximation. It is found in common that the energy bands in the vicinity of the Fermi level are mainly due to the hybridization between Pu 5/ and monochalcogenide p electrons. The obtained main Fermi surfaces are composed of two hole sheets and one electron sheet, all of which are constructed from the band having the Pu 5/ state and the monochalcogenide p state.

Theoretical investigations on structural, elastic and electronic properties of thallium halides

NASA Astrophysics Data System (ADS)

Singh, Rishi Pal; Singh, Rajendra Kumar; Rajagopalan, Mathrubutham

2011-04-01

Theoretical investigations on structural, elastic and electronic properties, viz. ground state lattice parameter, elastic moduli and density of states, of thallium halides (viz. TlCl and TlBr) have been made using the full potential linearized augmented plane wave method within the generalized gradient approximation (GGA). The ground state lattice parameter and bulk modulus and its pressure derivative have been obtained using optimization method. Young's modulus, shear modulus, Poisson ratio, sound velocities for longitudinal and shear waves, Debye average velocity, Debye temperature and Grüneisen parameter have also been calculated for these compounds. Calculated structural, elastic and other parameters are in good agreement with the available data.

First principle study of UHTC ternary diboride, Cr2AlB2

NASA Astrophysics Data System (ADS)

Rastogi, Anugya; Rajpoot, Priyanka; Verma, U. P.

2018-04-01

In this paper ab-initio study of the structural, electronic and optical properties of ternary metal boride Cr2AlB2 using full potential linear augmented plane wave (FP-LAPW) method based on the density functional theory (DFT). The study of structural properties shows that Cr2AlB2 is metallic in nature and have orthorhombic crystal structure. The optical properties show that it possess anisotropic behavior, which have wide applications in electricity production through concentration of solar power (CSP) technology. To the best of our knowledge, theoretical study of the optical properties of Cr2AlB2 is reported for the first time.

Structural, electronic and elastic properties of heavy fermion YbRh2 Laves phase compound

NASA Astrophysics Data System (ADS)

Pawar, Harsha; Shugani, Mani; Aynyas, Mahendra; Sanyal, Sankar P.

2018-05-01

The structural, electronic and elastic properties of YbRh2 Laves phase intermetallic compound which crystallize in cubic (MgCu2-type) structure have been investigated using ab-initio full potential linearized augmented plane wave (FP- LAPW) method with LDA and LDA+U approximation. The calculated ground state properties such as lattice parameter (a0), bulk modulus (B) and its pressure derivative (B') are in good agreement with available experimental and theoretical data. The electronic properties are analyzed from band structures and density of states. Elastic constants are predicted first time for this compound which obeys the stability criteria for cubic system.

The Pulse Detonation Rocket Induced MHD Ejector (PDRIME) Concept (Preprint)

DTIC Science & Technology

2008-06-10

flight applications. Thrust augmentation , such as PDE- ejector configurations, can potentially alleviate this problem. Here, we study the potential...flow, to assist in augmentation of the thrust . Ejectors typically transfer energy between streams through shear stress between separate flow streams...and the ejector operates. This is one of several configurations in which the PDRIME concept could be used for thrust augmentation in advanced

Generating Nice Linear Systems for Matrix Gaussian Elimination

ERIC Educational Resources Information Center

Homewood, L. James

2004-01-01

In this article an augmented matrix that represents a system of linear equations is called nice if a sequence of elementary row operations that reduces the matrix to row-echelon form, through matrix Gaussian elimination, does so by restricting all entries to integers in every step. Many instructors wish to use the example of matrix Gaussian…

New dual asymmetric CEC linear Fresnel concentrator for evacuated tubular receivers

NASA Astrophysics Data System (ADS)

Canavarro, Diogo; Chaves, Julio; Collares-Pereira, Manuel

2017-06-01

Linear Fresnel Reflector concentrators (LFR) are a potential solution for low-cost electricity production. Nevertheless in order to become more competitive with other CSP (Concentrated Solar Power) technologies, in particular with the Parabolic Trough concentrator, their overall solar to electricity efficiencies must increase. A possible path to achieve this goal is to increase the concentration factor, hence increasing the working temperatures for higher thermodynamic efficiency (more energy collection) and decrease the total number of rows of the solar field (less parasitic losses and corresponding cost reduction). This paper presents a dual asymmetric CEC-type (Compound Elliptical Concentrator) LFR (Linear Fresnel Concentrator) for evacuated tubular receivers. The concentrator is designed for a high concentration factor, presenting an asymmetric configuration enabling a very compact solution. The CEC-type secondary mirror is introduced to accommodate very high concentration values with a wide enough acceptance-angle (augmenting optical tolerances) for simple mechanical tracking solutions, achieving a higher CAP (Concentration Acceptance Product) in comparison with conventional LFR solutions. The paper presents an optical and thermal analysis of the concentrator using two different locations, Faro (Portugal) and Hurghada (Egypt).

Augmentation of Rocket Propulsion: Physical Limits

NASA Technical Reports Server (NTRS)

Taylor, Charles R.

1996-01-01

Rocket propulsion is not ideal when the propellant is not ejected at a unique velocity in an inertial frame. An ideal velocity distribution requires that the exhaust velocity vary linearly with the velocity of the vehicle in an inertial frame. It also requires that the velocity distribution variance as a thermodynamic quantity be minimized. A rocket vehicle with an inert propellant is not optimal, because it does not take advantage of the propellant mass for energy storage. Nor is it logical to provide another energy storage device in order to realize variable exhaust velocity, because it would have to be partly unfilled at the beginning of the mission. Performance is enhanced by pushing on the surrounding because it increases the reaction mass and decreases the reaction jet velocity. This decreases the fraction of the energy taken away by the propellant and increases the share taken by the payload. For an optimal model with the propellant used as fuel, the augmentation realized by pushing on air is greatest for vehicles with a low initial/final mass ratio. For a typical vehicle in the Earth's atmosphere, the augmentation is seen mainly at altitudes below about 80 km. When drag is taken into account, there is a well-defined optimum size for the air intake. Pushing on air has the potential to increase the performance of rockets which pass through the atmosphere. This is apart from benefits derived from "air breathing", or using the oxygen in the atmosphere to reduce the mass of an on-board oxidizer. Because of the potential of these measures, it is vital to model these effects more carefully and explore technology that may realize their advantages.

The incomplete inverse and its applications to the linear least squares problem

NASA Technical Reports Server (NTRS)

Morduch, G. E.

1977-01-01

A modified matrix product is explained, and it is shown that this product defiles a group whose inverse is called the incomplete inverse. It was proven that the incomplete inverse of an augmented normal matrix includes all the quantities associated with the least squares solution. An answer is provided to the problem that occurs when the data residuals are too large and when insufficient data to justify augmenting the model are available.

RMS active damping augmentation

NASA Technical Reports Server (NTRS)

Gilbert, Michael G.; Scott, Michael A.; Demeo, Martha E.

1992-01-01

The topics are presented in viewgraph form and include: RMS active damping augmentation; potential space station assembly benefits to CSI; LaRC/JSC bridge program; control law design process; draper RMS simulator; MIMO acceleration control laws improve damping; potential load reduction benefit; DRS modified to model distributed accelerations; accelerometer location; Space Shuttle aft cockpit simulator; simulated shuttle video displays; SES test goals and objectives; and SES modifications to support RMS active damping augmentation.

Current Status of Tissue-Engineered Scaffolds for Rotator Cuff Repair.

PubMed

Chainani, Abby; Little, Dianne

2016-06-01

Rotator cuff tears continue to be at significant risk for re-tear or for failure to heal after surgical repair despite the use of a variety of surgical techniques and augmentation devices. Therefore, there is a need for functionalized scaffold strategies to provide sustained mechanical augmentation during the critical first 12-weeks following repair, and to enhance the healing potential of the repaired tendon and tendon-bone interface. Tissue engineered approaches that combine the use of scaffolds, cells, and bioactive molecules towards promising new solutions for rotator cuff repair are reviewed. The ideal scaffold should have adequate initial mechanical properties, be slowly degrading or non-degradable, have non-toxic degradation products, enhance cell growth, infiltration and differentiation, promote regeneration of the tendon-bone interface, be biocompatible and have excellent suture retention and handling properties. Scaffolds that closely match the inhomogeneity and non-linearity of the native rotator cuff may significantly advance the field. While substantial pre-clinical work remains to be done, continued progress in overcoming current tissue engineering challenges should allow for successful clinical translation.

Current Status of Tissue-Engineered Scaffolds for Rotator Cuff Repair

PubMed Central

Chainani, Abby; Little, Dianne

2015-01-01

Rotator cuff tears continue to be at significant risk for re-tear or for failure to heal after surgical repair despite the use of a variety of surgical techniques and augmentation devices. Therefore, there is a need for functionalized scaffold strategies to provide sustained mechanical augmentation during the critical first 12-weeks following repair, and to enhance the healing potential of the repaired tendon and tendon-bone interface. Tissue engineered approaches that combine the use of scaffolds, cells, and bioactive molecules towards promising new solutions for rotator cuff repair are reviewed. The ideal scaffold should have adequate initial mechanical properties, be slowly degrading or non-degradable, have non-toxic degradation products, enhance cell growth, infiltration and differentiation, promote regeneration of the tendon-bone interface, be biocompatible and have excellent suture retention and handling properties. Scaffolds that closely match the inhomogeneity and non-linearity of the native rotator cuff may significantly advance the field. While substantial pre-clinical work remains to be done, continued progress in overcoming current tissue engineering challenges should allow for successful clinical translation. PMID:27346922

Early augmented language intervention for children with developmental delays: potential secondary motor outcomes.

PubMed

Whitmore, Ani S; Romski, Mary Ann; Sevcik, Rose A

2014-09-01

This exploratory study examined the potential secondary outcome of an early augmented language intervention that incorporates speech-generating devices (SGD) on motor skill use for children with developmental delays. The data presented are from a longitudinal study by Romski and colleagues. Toddlers in the augmented language interventions were either required (Augmented Communication-Output; AC-O) or not required (Augmented Communication-Input; AC-I) to use the SGD to produce an augmented word. Three standardized assessments and five event-based coding schemes measured the participants' language abilities and motor skills. Toddlers in the AC-O intervention used more developmentally appropriate motor movements and became more accurate when using the SGD to communicate than toddlers in the AC-I intervention. AAC strategies, interventionist/parent support, motor learning opportunities, and physical feedback may all contribute to this secondary benefit of AAC interventions that use devices.

Research In Nonlinear Flight Control for Tiltrotor Aircraft Operating in the Terminal Area

NASA Technical Reports Server (NTRS)

Calise, A. J.; Rysdyk, R.

1996-01-01

The research during the first year of the effort focused on the implementation of the recently developed combination of neural net work adaptive control and feedback linearization. At the core of this research is the comprehensive simulation code Generic Tiltrotor Simulator (GTRS) of the XV-15 tilt rotor aircraft. For this research the GTRS code has been ported to a Fortran environment for use on PC. The emphasis of the research is on terminal area approach procedures, including conversion from aircraft to helicopter configuration. This report focuses on the longitudinal control which is the more challenging case for augmentation. Therefore, an attitude command attitude hold (ACAH) control augmentation is considered which is typically used for the pitch channel during approach procedures. To evaluate the performance of the neural network adaptive control architecture it was necessary to develop a set of low order pilot models capable of performing such tasks as, follow desired altitude profiles, follow desired speed profiles, operate on both sides of powercurve, convert, including flaps as well as mastangle changes, operate with different stability and control augmentation system (SCAS) modes. The pilot models are divided in two sets, one for the backside of the powercurve and one for the frontside. These two sets are linearly blended with speed. The mastangle is also scheduled with speed. Different aspects of the proposed architecture for the neural network (NNW) augmented model inversion were also demonstrated. The demonstration involved implementation of a NNW architecture using linearized models from GTRS, including rotor states, to represent the XV-15 at various operating points. The dynamics used for the model inversion were based on the XV-15 operating at 30 Kts, with residualized rotor dynamics, and not including cross coupling between translational and rotational states. The neural network demonstrated ACAH control under various circumstances. Future efforts will include the implementation into the Fortran environment of GTRS, including pilot modeling and NNW augmentation for the lateral channels. These efforts should lead to the development of architectures that will provide for fully automated approach, using similar strategies.

Transforming Polar Research with Google Glass Augmented Reality (Invited)

NASA Astrophysics Data System (ADS)

Ruthkoski, T.

2013-12-01

Augmented reality is a new technology with the potential to accelerate the advancement of science, particularly in geophysical research. Augmented reality is defined as a live, direct or indirect, view of a physical, real-world environment whose elements are augmented (or supplemented) by computer-generated sensory input such as sound, video, graphics or GPS data. When paired with advanced computing techniques on cloud resources, augmented reality has the potential to improve data collection techniques, visualizations, as well as in-situ analysis for many areas of research. Google is currently a pioneer of augmented reality technology and has released beta versions of their wearable computing device, Google Glass, to a select number of developers and beta testers. This community of 'Glass Explorers' is the vehicle from which Google shapes the future of their augmented reality device. Example applications of Google Glass in geophysical research range from use as a data gathering interface in harsh climates to an on-site visualization and analysis tool. Early participation in the shaping of the Google Glass device is an opportunity for researchers to tailor this new technology to their specific needs. The purpose of this presentation is to provide geophysical researchers with a hands-on first look at Google Glass and its potential as a scientific tool. Attendees will be given an overview of the technical specifications as well as a live demonstration of the device. Potential applications to geophysical research in polar regions will be the primary focus. The presentation will conclude with an open call to participate, during which attendees may indicate interest in developing projects that integrate Google Glass into their research. Application Mockup: Penguin Counter Google Glass Augmented Reality Device

Transforming Polar Research with Google Glass Augmented Reality (Invited)

NASA Astrophysics Data System (ADS)

Ramachandran, R.; McEniry, M.; Maskey, M.

2011-12-01

Augmented reality is a new technology with the potential to accelerate the advancement of science, particularly in geophysical research. Augmented reality is defined as a live, direct or indirect, view of a physical, real-world environment whose elements are augmented (or supplemented) by computer-generated sensory input such as sound, video, graphics or GPS data. When paired with advanced computing techniques on cloud resources, augmented reality has the potential to improve data collection techniques, visualizations, as well as in-situ analysis for many areas of research. Google is currently a pioneer of augmented reality technology and has released beta versions of their wearable computing device, Google Glass, to a select number of developers and beta testers. This community of 'Glass Explorers' is the vehicle from which Google shapes the future of their augmented reality device. Example applications of Google Glass in geophysical research range from use as a data gathering interface in harsh climates to an on-site visualization and analysis tool. Early participation in the shaping of the Google Glass device is an opportunity for researchers to tailor this new technology to their specific needs. The purpose of this presentation is to provide geophysical researchers with a hands-on first look at Google Glass and its potential as a scientific tool. Attendees will be given an overview of the technical specifications as well as a live demonstration of the device. Potential applications to geophysical research in polar regions will be the primary focus. The presentation will conclude with an open call to participate, during which attendees may indicate interest in developing projects that integrate Google Glass into their research. Application Mockup: Penguin Counter Google Glass Augmented Reality Device

Metastable Autoionizing States of Molecules and Radicals in Highly Energetic Environment

DTIC Science & Technology

2016-03-22

electronic states. The specific aims are to develop and calibrate complex-scaled equation-of-motion coupled cluster (cs-EOM- CC ) and CAP (complex...absorbing potential) augmented EOM- CC methods. We have implemented and benchmarked cs-EOM-CCSD and CAP- augmented EOM-CCSD methods for excitation energies...motion coupled cluster (cs-EOM- CC ) and CAP (complex absorbing potential) augmented EOM- CC methods. We have implemented and benchmarked cs-EOM-CCSD and

Modeling a novel hypothetical use of postal collection boxes as automated external defibrillator access points.

PubMed

Srinivasan, Sanjana; Salerno, Jessica; Hajari, Hadi; Weiss, Lenny S; Salcido, David D

2017-11-01

Optimizing placement of Automated External Defibrillators (AED) can increase survival after an out-of-hospital cardiac arrest (OHCA). Using postal collection boxes (PCB) as locations for AEDs could potentially enhance accessibility and streamline maintenance. In this study, we modeled the hypothetical effects of deploying AEDs at PCB locations. We hypothesized that PCB-AEDs would increase AED coverage overall and in residential areas, and reduce the distance from OHCA to an AED. AEDs in Pittsburgh, PA were identified by the University of Pittsburgh Resuscitation Logistics and Informatics Venture (n=747). PCB locations were obtained from the United States Postal Service (n=479). OHCA locations from 2009 to 2014 were obtained from the Pittsburgh site of the Resuscitation Outcomes Consortium. AED coverage assuming a ¼ mile radius around each AED was estimated for known AEDs, PCB-AEDs (hypothetical AED locations), and known AEDs augmented by PCB-AEDs, both overall and for residential and non-residential zones. Linear distance from each OHCA to the nearest AED was calculated and compared between the sets. The set of known AEDs augmented with PCB-AEDs covered more of the city overall (55% vs 30%), as well as greater proportions of residential (62% vs 27%) and non-residential areas (45% vs 30%). The median distance from OHCA to AED was significantly shorter when known AEDs were augmented with PCB-AEDs (0.12mi vs 0.32mi; p=0.001). Augmenting existing publicly accessible AEDs with AEDs deployed at PCBs can increase AED spatial coverage in both residential and non-residential areas, and reduce the distance from AED to OHCA. Copyright © 2017 Elsevier B.V. All rights reserved.

Arterial pulse wave velocity but not augmentation index is associated with coronary artery disease extent and severity: implications for arterial transfer function applicability.

PubMed

Hope, Sarah A; Antonis, Paul; Adam, David; Cameron, James D; Meredith, Ian T

2007-10-01

The aim of this study was to test the hypothesis that coronary artery disease extent and severity are associated with central aortic pressure waveform characteristics. Although it is thought that central aortic pressure waveform characteristics, particularly augmentation index, may influence cardiovascular disease progression and predict cardiovascular risk, little is known of the relationship between central waveform characteristics and the severity and extent of coronary artery disease. Central aortic waveforms (2F Millar pressure transducer-tipped catheters) were acquired at the time of coronary angiography for suspected native coronary artery disease in 40 patients (24 male). The severity and extent of disease were assessed independently by two observers using two previously described scoring systems (modified Gensini's stenosis and Sullivan's extent scores). Relationships between disease scores, aortic waveform characteristics, aorto-radial pulse wave velocity and subject demographic features were assessed by regression techniques. Both extent and severity scores were associated with increasing age and male sex (P < 0.001), but no other risk factors. Both scores were independently associated with aorto-radial pulse wave velocity (P < 0.001), which entered a multiple regression model prior to age and sex. This association was not dependent upon blood pressure. Neither score was associated with central aortic augmentation index, by either simple or multiple linear regression techniques including heart rate, subject demographic features and cardiovascular risk factors. Aorto-radial pulse wave velocity, but not central aortic augmentation index, is associated with both the extent and severity of coronary artery disease. This has potentially important implications for applicability of a generalized arterial transfer function.

Volumetric and linear changes at dental implants following grafting with volume-stable three-dimensional collagen matrices or autogenous connective tissue grafts: 6-month data.

PubMed

Naenni, Nadja; Bienz, Stefan P; Benic, Goran I; Jung, Ronald E; Hämmerle, Christoph H F; Thoma, Daniel S

2018-04-01

The objective of this study was to test whether or not soft tissue augmentation with a volume-stable collagen matrix (VCMX) leads to similar volume gain around dental implants compared to autogenous subepithelial connective tissue graft (SCTG). In 12 adult beagle dogs, immediate implants were placed with simultaneous guided bone regeneration. After 25-45 weeks, soft tissue augmentation was randomly performed using VCMX, SCTG, or a sham-operated control. Impressions were taken pre-op and post-op (tissue augmentation) and again at sacrifice after healing periods of 4, 8, and 24 weeks. They were then digitized to allow for superimposition. Values of linear and volumetric changes were calculated. The median increase (pre-op to post-op) in buccal volume measured 0.92 mm for VCMX, 1.47 mm for SCTG, and 0.24 mm for SH. The values (pre-op to sacrifice) were - 0.25 mm for VCMX, 0.52 mm for SCTG, and - 0.06 mm for group SH. The median ridge width 2 mm below the crest measured - 0.26 mm for VCMX, 0.53 mm for SCTG, and - 0.15 mm for SH (pre-op to sacrifice). Volume augmentation using VCMX and SCTG resulted in an increase in ridge dimension (pre- to post-op). During the follow-up, the volume decreased in all three groups to a level close to the situation prior to surgery. Soft tissue volume augmentation around dental implants is usually performed using the patient's own tissue. This therapy is associated with an increased morbidity due to a second surgical site. Soft tissue volume at implant sites can be augmented using VCMX and SCTG. The gain on top of the ridge appears not to be stable during the follow-up in both groups.

Role of structural relaxations and chemical substitutions on piezoelectric fields and potential lineup in GaN/Al junctions

NASA Astrophysics Data System (ADS)

Picozzi, S.; Profeta, G.; Continenza, A.; Massidda, S.; Freeman, A. J.

2002-04-01

First-principles full-potential linearized augmented plane wave calculations are performed to clarify the role of the interface geometry on piezoelectric fields and potential lineups in [0001] wurtzite and [111]-zincblende GaN/Al junctions. The electric field (polarity and magnitude) is found to be strongly affected by atomic relaxations in the interface region. A procedure is used to evaluate the Schottky-barrier height in the presence of electric fields, showing that their effect is relatively small (a few tenths of an eV). These calculations assess the rectifying behavior of the GaN/Al contact, in agreement with experimental values for the barrier. We disentangle chemical and structural effects on the relevant properties (such as the potential discontinuity and the electric field) by studying unrelaxed ideal nitride/metal systems. Using simple electronegativity arguments, we outline the leading mechanisms that define the values of the electric field and Schottky barrier in these ideal systems. Finally, the transitivity rule is proved to be well satisfied.

Ghrelin Serum Concentrations Are Associated with Treatment Response During Lithium Augmentation of Antidepressants.

PubMed

Ricken, Roland; Bopp, Sandra; Schlattmann, Peter; Himmerich, Hubertus; Bschor, Tom; Richter, Christoph; Elstner, Samuel; Stamm, Thomas J; Schulz-Ratei, Brigitte; Lingesleben, Alexandra; Reischies, Friedel M; Sterzer, Philipp; Borgwardt, Stefan; Bauer, Michael; Heinz, Andreas; Hellweg, Rainer; Lang, Undine E; Adli, Mazda

2017-09-01

Lithium augmentation of antidepressants is an effective strategy in treatment-resistant depression. The proteohormone ghrelin is thought to be involved in the pathophysiology of depression. The purpose of this study was to investigate the association of treatment response with the course of ghrelin levels during lithium augmentation. Ghrelin serum concentrations and severity of depression were measured in 85 acute depressive patients before and after 4 weeks of lithium augmentation. In a linear mixed model analysis, we found a significant effect of response*time interaction (F1.81=9.48; P=.0028): under treatment, ghrelin levels increased in nonresponders and slightly decreased in responders to lithium augmentation. The covariate female gender had a significant positive effect (F1.83=4.69; P=.033), whereas time, response, appetite, and body mass index (kg/m2) did not show any significant effect on ghrelin levels (P>.05). This is the first study showing that the course of ghrelin levels separates responders and nonresponders to lithium augmentation. Present results support the hypothesis that ghrelin serum concentrations might be involved in response to pharmacological treatment of depression. © The Author 2017. Published by Oxford University Press on behalf of CINP.

Ghrelin Serum Concentrations Are Associated with Treatment Response During Lithium Augmentation of Antidepressants

PubMed Central

Bopp, Sandra; Schlattmann, Peter; Himmerich, Hubertus; Bschor, Tom; Richter, Christoph; Elstner, Samuel; Stamm, Thomas J; Schulz-Ratei, Brigitte; Lingesleben, Alexandra; Reischies, Friedel M; Sterzer, Philipp; Borgwardt, Stefan; Bauer, Michael; Heinz, Andreas; Hellweg, Rainer; Lang, Undine E; Adli, Mazda

2017-01-01

Abstract Background Lithium augmentation of antidepressants is an effective strategy in treatment-resistant depression. The proteohormone ghrelin is thought to be involved in the pathophysiology of depression. The purpose of this study was to investigate the association of treatment response with the course of ghrelin levels during lithium augmentation. Method Ghrelin serum concentrations and severity of depression were measured in 85 acute depressive patients before and after 4 weeks of lithium augmentation. Results In a linear mixed model analysis, we found a significant effect of response*time interaction (F1.81=9.48; P=.0028): under treatment, ghrelin levels increased in nonresponders and slightly decreased in responders to lithium augmentation. The covariate female gender had a significant positive effect (F1.83=4.69; P=.033), whereas time, response, appetite, and body mass index (kg/m2) did not show any significant effect on ghrelin levels (P>.05). Conclusion This is the first study showing that the course of ghrelin levels separates responders and nonresponders to lithium augmentation. Present results support the hypothesis that ghrelin serum concentrations might be involved in response to pharmacological treatment of depression. PMID:28911006

Quantitative analysis of eyes and other optical systems in linear optics.

PubMed

Harris, William F; Evans, Tanya; van Gool, Radboud D

2017-05-01

To show that 14-dimensional spaces of augmented point P and angle Q characteristics, matrices obtained from the ray transference, are suitable for quantitative analysis although only the latter define an inner-product space and only on it can one define distances and angles. The paper examines the nature of the spaces and their relationships to other spaces including symmetric dioptric power space. The paper makes use of linear optics, a three-dimensional generalization of Gaussian optics. Symmetric 2 × 2 dioptric power matrices F define a three-dimensional inner-product space which provides a sound basis for quantitative analysis (calculation of changes, arithmetic means, etc.) of refractive errors and thin systems. For general systems the optical character is defined by the dimensionally-heterogeneous 4 × 4 symplectic matrix S, the transference, or if explicit allowance is made for heterocentricity, the 5 × 5 augmented symplectic matrix T. Ordinary quantitative analysis cannot be performed on them because matrices of neither of these types constitute vector spaces. Suitable transformations have been proposed but because the transforms are dimensionally heterogeneous the spaces are not naturally inner-product spaces. The paper obtains 14-dimensional spaces of augmented point P and angle Q characteristics. The 14-dimensional space defined by the augmented angle characteristics Q is dimensionally homogenous and an inner-product space. A 10-dimensional subspace of the space of augmented point characteristics P is also an inner-product space. The spaces are suitable for quantitative analysis of the optical character of eyes and many other systems. Distances and angles can be defined in the inner-product spaces. The optical systems may have multiple separated astigmatic and decentred refracting elements. © 2017 The Authors Ophthalmic & Physiological Optics © 2017 The College of Optometrists.

The application of parameter estimation to flight measurements to obtain lateral-directional stability derivatives of an augmented jet-flap STOL airplane

NASA Technical Reports Server (NTRS)

Stephenson, J. D.

1983-01-01

Flight experiments with an augmented jet flap STOL aircraft provided data from which the lateral directional stability and control derivatives were calculated by applying a linear regression parameter estimation procedure. The tests, which were conducted with the jet flaps set at a 65 deg deflection, covered a large range of angles of attack and engine power settings. The effect of changing the angle of the jet thrust vector was also investigated. Test results are compared with stability derivatives that had been predicted. The roll damping derived from the tests was significantly larger than had been predicted, whereas the other derivatives were generally in agreement with the predictions. Results obtained using a maximum likelihood estimation procedure are compared with those from the linear regression solutions.

Linear landmark extraction in SAR images with application to augmented integrity aero-navigation: an overview to a novel processing chain

NASA Astrophysics Data System (ADS)

Fabbrini, L.; Messina, M.; Greco, M.; Pinelli, G.

2011-10-01

In the context of augmented integrity Inertial Navigation System (INS), recent technological developments have been focusing on landmark extraction from high-resolution synthetic aperture radar (SAR) images in order to retrieve aircraft position and attitude. The article puts forward a processing chain that can automatically detect linear landmarks on highresolution synthetic aperture radar (SAR) images and can be successfully exploited also in the context of augmented integrity INS. The processing chain uses constant false alarm rate (CFAR) edge detectors as the first step of the whole processing procedure. Our studies confirm that the ratio of averages (RoA) edge detector detects object boundaries more effectively than Student T-test and Wilcoxon-Mann-Whitney (WMW) test. Nevertheless, all these statistical edge detectors are sensitive to violation of the assumptions which underlie their theory. In addition to presenting a solution to the previous problem, we put forward a new post-processing algorithm useful to remove the main false alarms, to select the most probable edge position, to reconstruct broken edges and finally to vectorize them. SAR images from the "MSTAR clutter" dataset were used to prove the effectiveness of the proposed algorithms.

Optical See-Through Head Mounted Display Direct Linear Transformation Calibration Robustness in the Presence of User Alignment Noise

NASA Technical Reports Server (NTRS)

Axholt, Magnus; Skoglund, Martin; Peterson, Stephen D.; Cooper, Matthew D.; Schoen, Thomas B.; Gustafsson, Fredrik; Ynnerman, Anders; Ellis, Stephen R.

2010-01-01

Augmented Reality (AR) is a technique by which computer generated signals synthesize impressions that are made to coexist with the surrounding real world as perceived by the user. Human smell, taste, touch and hearing can all be augmented, but most commonly AR refers to the human vision being overlaid with information otherwise not readily available to the user. A correct calibration is important on an application level, ensuring that e.g. data labels are presented at correct locations, but also on a system level to enable display techniques such as stereoscopy to function properly [SOURCE]. Thus, vital to AR, calibration methodology is an important research area. While great achievements already have been made, there are some properties in current calibration methods for augmenting vision which do not translate from its traditional use in automated cameras calibration to its use with a human operator. This paper uses a Monte Carlo simulation of a standard direct linear transformation camera calibration to investigate how user introduced head orientation noise affects the parameter estimation during a calibration procedure of an optical see-through head mounted display.

Structural, electronic and thermal properties of super hard ternary boride, WAlB

NASA Astrophysics Data System (ADS)

Rajpoot, Priyanka; Rastogi, Anugya; Verma, U. P.

2018-04-01

A first principle study of the structural, electronic and thermal properties of Tungsten Aluminum Boride (WAlB) using full-potential linearized augmented plane wave (FP-LAPW) in the frame work of density function theory (DFT) have been calculated. The calculated equilibrium structural parameters are in excellent agreement with available experimental results. The calculated electronic band structure reveals that WAlB is metallic in nature. The quasi-harmonic Debye model is applied to study of the temperature and pressure effect on volume, Debye temperature, thermal expansion coefficient and specific heat at constant volume and constant pressure. To the best of our knowledge theoretical investigation of these properties of WAlB is reported for the first time.

Observation of high magnetocrystalline anisotropy on Co doping in rare earth free Fe2P magnetic material

NASA Astrophysics Data System (ADS)

Thakur, Jyoti; Singh, Om Pal; Tomar, Monika; Gupta, Vinay; Kashyap, Manish K.

2018-04-01

ab-initio investigation of magnetocrystalline anisotropy energy (MAE) for Fe2P and CoFeP using density functional theory based full-potential linear augmented plane wave (FPLAPW) is reported. CoFeP alloy exhibits large magnetic moment 13.28 µB and enhanced anisotropy energy reaching as high as 1326 µeV/f.u. This energy is nearly doubled as compared to its parent Fe2P alloy, making this system a promising candidate for a rare earth free permanent magnet. Substituitng Co at Fe-3f site in Fe2P helps in stabilizing the new structure and further improves the magnetic properties.

Structural, Electronic and Elastic Properties of Heavy Fermion YbTM2 (TM= Ir and Pt) Laves Phase Compounds

NASA Astrophysics Data System (ADS)

Pawar, H.; Shugani, M.; Aynyas, M.; Sanyal, S. P.

2018-02-01

The structural, electronic and elastic properties of YbTM2 (TM = Ir and Pt) Laves phase intermetallic compounds which crystallize in cubic (MgCu2-type) structure, have been investigated using ab-initio full potential linearized augmented plane wave (FP-LAPW) method with LDA and LDA+U approximation. The calculated ground state properties such as lattice parameter (a0), bulk modulus (B) and its pressure derivative (B‧) are in good agreement with available experimental and theoretical data. The electronic properties are analyzed from band structures and density of states. Elastic constants are predicted first time for these compounds which obey the stability criteria for cubic system.

Ab-initio thermodynamic and elastic properties of AlNi and AlNi3 intermetallic compounds

NASA Astrophysics Data System (ADS)

Yalameha, Shahram; Vaez, Aminollah

2018-04-01

In this paper, thermodynamic and elastic properties of the AlNi and AlNi3 were investigated using density functional theory (DFT). The full-potential linearized augmented plane-wave (APW) in the framework of the generalized gradient approximation as used as implemented in the Wien2k package. The temperature dependence of thermal expansion coefficient, bulk modulus and heat capacity in a wide range of temperature (0-1600 K) were investigated. The calculated elastic properties of the compounds show that both intermetallic compounds of AlNi and AlNi3 have surprisingly negative Poisson’s ratio (NPR). The results were compared with other experimental and computational data.

Density of states, optical and thermoelectric properties of perovskite vanadium fluorides Na3VF6

NASA Astrophysics Data System (ADS)

Reshak, A. H.; Azam, Sikander

2014-05-01

The electronic structure, charge density and Fermi surface of Na3VF6 compound have been examined with the support of density functional theory (DFT). Using the full potential linear augmented plane wave method, we employed the local density approximation (LDA), generalized gradient approximation (GGA) and Engel-Vosko GGA (EVGGA) to treat the exchange correlation potential to solve Kohn-Sham equations. The calculation show that Na3VF6 compound has metallic nature and the Fermi energy (EF) is assessed by overlapping of V-d state. The calculated density of states at the EF are about 18.655, 51.932 and 13.235 states/eV, and the bare linear low-temperature electronic specific heat coefficient (γ) is found to be 3.236 mJ/mol-K2, 9.008 mJ/mol-K2 and 2.295 mJ/mol-K2 for LDA, GGA and EVGGA, respectively. The Fermi surface is composed of two sheets. The chemical bonding of Na3VF6 compound is analyzed through the electronic charge density in the (1 1 0) crystallographic plane. The optical constants and thermal properties were also calculated and discussed.

Robot-Arm Dynamic Control by Computer

NASA Technical Reports Server (NTRS)

Bejczy, Antal K.; Tarn, Tzyh J.; Chen, Yilong J.

1987-01-01

Feedforward and feedback schemes linearize responses to control inputs. Method for control of robot arm based on computed nonlinear feedback and state tranformations to linearize system and decouple robot end-effector motions along each of cartesian axes augmented with optimal scheme for correction of errors in workspace. Major new feature of control method is: optimal error-correction loop directly operates on task level and not on joint-servocontrol level.

Randomized controlled clinical study comparing a volume-stable collagen matrix to autogenous connective tissue grafts for soft tissue augmentation at implant sites: linear volumetric soft tissue changes up to 3 months.

PubMed

Zeltner, Marco; Jung, Ronald E; Hämmerle, Christoph H F; Hüsler, Jürg; Thoma, Daniel S

2017-04-01

To test whether or not the use of a volume-stable collagen matrix (VCMX) results in soft tissue volume increase at implant sites non-inferior to an autogenous subepithelial connective tissue graft (SCTG). In 20 patients, soft tissue augmentation at implant sites was performed using VCMX or SCTG. Casts obtained prior to augmentation (BL), at 30 (FU-30) and 90 days (FU-90) were digitized and transferred to stereolithography (STL) files. BL, FU-30 and FU-90 STL files were superimposed and linear volumetric changes evaluated in crestal and buccal regions of interest (ROI). Descriptive analysis was computed for both groups and a test for non-inferiority was performed. The median linear changes from BL to FU-90 in the crestal ROI amounted to 0.175 mm (0.06; 0.51) for VCMX (p = 0.002 over time) and to 0.51 mm (0.23; 0.94) for SCTG (p = 0.129). The differences between the two groups were not significant (p = 0.287). The respective values in the buccal ROI were 0.59 mm (0.26; 1.06) for VCMX (p = 0.002) and 0.94 mm (0.66; 1.13) for SCTG (p = 0.004). The differences between the two groups were not significant (crestal: p = 0.287; buccal: p = 0.534). Non-inferiority could be concluded for VCMX compared to SCTG for both ROI. VCMX and SCTG can be used for soft tissue augmentation at implant sites resulting in an at least short-term increase in volume. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Parallelization of the FLAPW method and comparison with the PPW method

NASA Astrophysics Data System (ADS)

Canning, Andrew; Mannstadt, Wolfgang; Freeman, Arthur

2000-03-01

The FLAPW (full-potential linearized-augmented plane-wave) method is one of the most accurate first-principles methods for determining electronic and magnetic properties of crystals and surfaces. In the past the FLAPW method has been limited to systems of about a hundred atoms due to the lack of an efficient parallel implementation to exploit the power and memory of parallel computers. In this work we present an efficient parallelization of the method by division among the processors of the plane-wave components for each state. The code is also optimized for RISC (reduced instruction set computer) architectures, such as those found on most parallel computers, making full use of BLAS (basic linear algebra subprograms) wherever possible. Scaling results are presented for systems of up to 686 silicon atoms and 343 palladium atoms per unit cell running on up to 512 processors on a Cray T3E parallel supercomputer. Some results will also be presented on a comparison of the plane-wave pseudopotential method and the FLAPW method on large systems.

Nonlinear Schrödinger approach to European option pricing

NASA Astrophysics Data System (ADS)

Wróblewski, Marcin

2017-05-01

This paper deals with numerical option pricing methods based on a Schrödinger model rather than the Black-Scholes model. Nonlinear Schrödinger boundary value problems seem to be alternatives to linear models which better reflect the complexity and behavior of real markets. Therefore, based on the nonlinear Schrödinger option pricing model proposed in the literature, in this paper a model augmented by external atomic potentials is proposed and numerically tested. In terms of statistical physics the developed model describes the option in analogy to a pair of two identical quantum particles occupying the same state. The proposed model is used to price European call options on a stock index. the model is calibrated using the Levenberg-Marquardt algorithm based on market data. A Runge-Kutta method is used to solve the discretized boundary value problem numerically. Numerical results are provided and discussed. It seems that our proposal more accurately models phenomena observed in the real market than do linear models.

Steady-state sinusoidal behavior of elastomeric dampers

NASA Astrophysics Data System (ADS)

Madhavan, Vijay; Wereley, Norman M.; Sieg, Thierry

1999-06-01

This paper presents an experimental and analytical investigation of an elastomeric damping material and assesses its potential application to stability augmentation of hingeless and bearingless helicopter rotors. Double lap shear specimens were tested on a servo-hydraulic testing machine. Single frequency sinusoidal tests were conducted over a strain amplitude range of 0 - 30% at three frequencies (lag/rev, 1/rev and a lower harmonic of the rotor). The frequencies were chosen such that the effect of the damper in mitigating instability phenomena, like ground and air resonance, could be analyzed. The effects of frequency, amplitude, pre-load and material self-heating were studied. A three-element mechanisms-based damper model was developed that accurately captures the energy dissipation and hysteresis behavior of the damper. The model incorporates a linear stiffness, viscous damping and a non-linear slip element that are placed in parallel to each other. The parameters of the model were identified using an LMS technique. The model was validated by reconstructing measured hysteresis cycles using these parameters.

A preliminary look at control augmented dynamic response of structures

NASA Technical Reports Server (NTRS)

Ryan, R. S.; Jewell, R. E.

1983-01-01

The augmentation of structural characteristics, mass, damping, and stiffness through the use of control theory in lieu of structural redesign or augmentation was reported. The standard single-degree-of-freedom system was followed by a treatment of the same system using control augmentation. The system was extended to elastic structures using single and multisensor approaches and concludes with a brief discussion of potential application to large orbiting space structures.

Magnetohydrodynamic Augmentation of Pulse Detonation Rocket Engines (Preprint)

DTIC Science & Technology

2010-09-28

augmentation of the thrust . Ejectors typically transfer energy between streams through shear stress between separate flow streams, where a portion of the...the opportunity to extract energy and apply it to a separate stream where the net thrust can be increased. With MHD augmentation , such as in the Pulse...with the PDRIME for separate or additional thrust augmentation . Results show potential performance gains under many flight and operating conditions

Potential costs of breast augmentation mammaplasty.

PubMed

Schmitt, William P; Eichhorn, Mitchell G; Ford, Ronald D

2016-01-01

Augmentation mammaplasty is one of the most common surgical procedures performed by plastic surgeons. The aim of this study was to estimate the cost of the initial procedure and its subsequent complications, as well as project the cost of Food and Drug Administration (FDA)-recommended surveillance imaging. The potential costs to the individual patient and society were calculated. Local plastic surgeons provided billing data for the initial primary silicone augmentation and reoperative procedures. Complication rates used for the cost analysis were obtained from the Allergen Core study on silicone implants. Imaging surveillance costs were considered in the estimations. The average baseline initial cost of silicone augmentation mammaplasty was calculated at $6335. The average total cost of primary breast augmentation over the first decade for an individual patient, including complications requiring reoperation and other ancillary costs, was calculated at $8226. Each decade thereafter cost an additional $1891. Costs may exceed $15,000 over an averaged lifetime, and the recommended implant surveillance could cost an additional $33,750. The potential cost of a breast augmentation, which includes the costs of complications and imaging, is significantly higher than the initial cost of the procedure. Level III, economic and decision analysis study. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

A new biphasic osteoinductive calcium composite material with a negative Zeta potential for bone augmentation

PubMed Central

Smeets, Ralf; Kolk, Andreas; Gerressen, Marcus; Driemel, Oliver; Maciejewski, Oliver; Hermanns-Sachweh, Benita; Riediger, Dieter; Stein, Jamal M

2009-01-01

The aim of the present study was to analyze the osteogenic potential of a biphasic calcium composite material (BCC) with a negative surface charge for maxillary sinus floor augmentation. In a 61 year old patient, the BCC material was used in a bilateral sinus floor augmentation procedure. Six months postoperative, a bone sample was taken from the augmented regions before two titanium implants were inserted at each side. We analyzed bone neoformation by histology, bone density by computed tomography, and measured the activity of voltage-activated calcium currents of osteoblasts and surface charge effects. Control orthopantomograms were carried out five months after implant insertion. The BCC was biocompatible and replaced by new mineralized bone after being resorbed completely. The material demonstrated a negative surface charge (negative Zeta potential) which was found to be favorable for bone regeneration and osseointegration of dental implants. PMID:19523239

Properties of Augmented Kohn-Sham Potential for Energy as Simple Sum of Orbital Energies.

PubMed

Zahariev, Federico; Levy, Mel

2017-01-12

A recent modification to the traditional Kohn-Sham method ( Levy , M. ; Zahariev , F. Phys. Rev. Lett. 2014 , 113 , 113002 ; Levy , M. ; Zahariev , F. Mol. Phys. 2016 , 114 , 1162 - 1164 ), which gives the ground-state energy as a direct sum of the occupied orbital energies, is discussed and its properties are numerically illustrated on representative atoms and ions. It is observed that current approximate density functionals tend to give surprisingly small errors for the highest occupied orbital energies that are obtained with the augmented potential. The appropriately shifted Kohn-Sham potential is the basic object within this direct-energy Kohn-Sham method and needs to be approximated. To facilitate approximations, several constraints to the augmented Kohn-Sham potential are presented.

NMR shieldings from density functional perturbation theory: GIPAW versus all-electron calculations

NASA Astrophysics Data System (ADS)

de Wijs, G. A.; Laskowski, R.; Blaha, P.; Havenith, R. W. A.; Kresse, G.; Marsman, M.

2017-02-01

We present a benchmark of the density functional linear response calculation of NMR shieldings within the gauge-including projector-augmented-wave method against all-electron augmented-plane-wave+local-orbital and uncontracted Gaussian basis set results for NMR shieldings in molecular and solid state systems. In general, excellent agreement between the aforementioned methods is obtained. Scalar relativistic effects are shown to be quite large for nuclei in molecules in the deshielded limit. The small component makes up a substantial part of the relativistic corrections.

NMR shieldings from density functional perturbation theory: GIPAW versus all-electron calculations.

PubMed

de Wijs, G A; Laskowski, R; Blaha, P; Havenith, R W A; Kresse, G; Marsman, M

2017-02-14

We present a benchmark of the density functional linear response calculation of NMR shieldings within the gauge-including projector-augmented-wave method against all-electron augmented-plane-wave+local-orbital and uncontracted Gaussian basis set results for NMR shieldings in molecular and solid state systems. In general, excellent agreement between the aforementioned methods is obtained. Scalar relativistic effects are shown to be quite large for nuclei in molecules in the deshielded limit. The small component makes up a substantial part of the relativistic corrections.

Design of an optimal preview controller for linear discrete-time descriptor systems with state delay

NASA Astrophysics Data System (ADS)

Cao, Mengjuan; Liao, Fucheng

2015-04-01

In this paper, the linear discrete-time descriptor system with state delay is studied, and a design method for an optimal preview controller is proposed. First, by using the discrete lifting technique, the original system is transformed into a general descriptor system without state delay in form. Then, taking advantage of the first-order forward difference operator, we construct a descriptor augmented error system, including the state vectors of the lifted system, error vectors, and desired target signals. Rigorous mathematical proofs are given for the regularity, stabilisability, causal controllability, and causal observability of the descriptor augmented error system. Based on these, the optimal preview controller with preview feedforward compensation for the original system is obtained by using the standard optimal regulator theory of the descriptor system. The effectiveness of the proposed method is shown by numerical simulation.

Machine Learning-based discovery of closures for reduced models of dynamical systems

NASA Astrophysics Data System (ADS)

Pan, Shaowu; Duraisamy, Karthik

2017-11-01

Despite the successful application of machine learning (ML) in fields such as image processing and speech recognition, only a few attempts has been made toward employing ML to represent the dynamics of complex physical systems. Previous attempts mostly focus on parameter calibration or data-driven augmentation of existing models. In this work we present a ML framework to discover closure terms in reduced models of dynamical systems and provide insights into potential problems associated with data-driven modeling. Based on exact closure models for linear system, we propose a general linear closure framework from viewpoint of optimization. The framework is based on trapezoidal approximation of convolution term. Hyperparameters that need to be determined include temporal length of memory effect, number of sampling points, and dimensions of hidden states. To circumvent the explicit specification of memory effect, a general framework inspired from neural networks is also proposed. We conduct both a priori and posteriori evaluations of the resulting model on a number of non-linear dynamical systems. This work was supported in part by AFOSR under the project ``LES Modeling of Non-local effects using Statistical Coarse-graining'' with Dr. Jean-Luc Cambier as the technical monitor.

Atomic and electronic structure of oxygen vacancies and Nb-impurity in SrTiO3

NASA Astrophysics Data System (ADS)

Hamid, A. S.

2009-12-01

We present the results of a first-principle full-potential linearized augmented plane wave (FLAPW) method to study the effect of defects on the electronic structure of SrTiO3. In addition, the relaxation of nearest neighbor atoms around those defects were calculated self-consistently. The calculations were performed using the local (spin) density approximations (L(S)DA), for the exchange-correlation potential. SrTiO3 was found to experience an insulator-to-metal transition upon the formation of oxygen vacancies or the substitution of Nb at the Ti site. The formation of oxygen divacancy disclosed additional states below the conduction band edge. The crystalline lattice relaxation showed displacements of atoms in rather large defective region. The magnitudes of atomic movements, however, were not large, normally not exceeding 0.15 Å. Our results were compared to the available experimental observations.

Mechanical, electronic and thermodynamic properties of full Heusler compounds Fe2VX(X = Al, Ga)

NASA Astrophysics Data System (ADS)

Khalfa, M.; Khachai, H.; Chiker, F.; Baki, N.; Bougherara, K.; Yakoubi, A.; Murtaza, G.; Harmel, M.; Abu-Jafar, M. S.; Omran, S. Bin; Khenata, R.

2015-11-01

The electronic structure, mechanical and thermodynamic properties of Fe2VX, (with X = Al and Ga), have been studied self consistently by employing state-of-the-art full-potential linearized approach of augmented plane wave plus local orbitals (FP-LAPW + lo) method. The exchange-correlation potential is treated with the local density and generalized gradient approximations (LDA and GGA). Our predicted ground state properties such as lattice constants, bulk modulus and elastic constants appear more accurate when we employed the GGA rather than the LDA, and these results are in very good agreement with the available experimental and theoretical data. Further, thermodynamic properties of Fe2VAl and Fe2VGa are predicted with pressure and temperature in the ranges of 0-40 GPa and 0-1500 K using the quasi-harmonic Debye model. We have obtained successfully the variations of the heat capacities, primitive cell volume and volume expansion coefficient.

Electronic structure, elasticity, bonding features and mechanical behaviour of zinc intermetallics: A DFT study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fatima, Bushra, E-mail: bushrafatima25@gmail.com; Acharya, Nikita; Sanyal, Sankar P.

2016-05-06

The structural stability, electronic structure, elastic and mechanical properties of TiZn and ZrZn intermetallics have been studied using ab-initio full potential linearized augmented plane wave (FP-LAPW) method within generalized gradient approximation for exchange and correlation potentials. The various structural parameters, such as lattice constant (a{sub 0}), bulk modulus (B), and its pressure derivative (B’) are analysed and compared. The investigation of elastic constants affirm that both TiZn and ZrZn are elastically stable in CsCl (B{sub 2} phase) structure. The electronic structures have been analysed quantitatively from the band structure which reveals the metallic nature of these compounds. To better illustratemore » the nature of bonding and charge transfer, we have also studied the Fermi surfaces. The three well known criterion of ductility namely Pugh’s rule, Cauchy’s pressure and Frantsevich rule elucidate the ductile nature of these compounds.« less

Theoretical band structure of the superconducting antiperovskite oxide Sr3-xSnO

NASA Astrophysics Data System (ADS)

Ikeda, Atsutoshi; Fukumoto, Toshiyuki; Oudah, Mohamed; Hausmann, Jan Niklas; Yonezawa, Shingo; Kobayashi, Shingo; Sato, Masatoshi; Tassel, Cédric; Takeiri, Fumitaka; Takatsu, Hiroshi; Kageyama, Hiroshi; Maeno, Yoshiteru

2018-05-01

In order to investigate the position of the strontium deficiency in superconductive Sr3-xSnO, we synthesized and measured X-ray-diffraction patterns of Sr3-xSnO (x ∼ 0.5). Because no clear peaks originating from superstructures were observed, strontium deficiency is most likely to be randomly distributed. We also performed first-principles band-structure calculations on Sr3-xSnO (x = 0, 0.5) using two methods: full-potential linearized-augmented plane-wave plus local orbitals method and the Korringa-Kohn-Rostoker Green function method combined with the coherent potential approximation. We revealed that the Fermi energy of Sr3-xSnO in case of x ∼ 0.5 is about 0.8 eV below the original Fermi energy of the stoichiometric Sr3SnO, where the mixing of the valence p and conduction d orbitals are considered to be small.

DFT-BASED AB INITIO STUDY OF THE ELECTRONIC AND OPTICAL PROPERTIES OF CESIUM BASED FLUORO-PEROVSKITE CsMF3 (M = Ca AND Sr)

NASA Astrophysics Data System (ADS)

Harmel, M.; Khachai, H.; Ameri, M.; Khenata, R.; Baki, N.; Haddou, A.; Abbar, B.; UǦUR, Ş.; Omran, S. Bin; Soyalp, F.

2012-12-01

Density functional theory (DFT) is performed to study the structural, electronic and optical properties of cubic fluoroperovskite AMF3 (A = Cs; M = Ca and Sr) compounds. The calculations are based on the total-energy calculations within the full-potential linearized augmented plane wave (FP-LAPW) method. The exchange-correlation potential is treated by local density approximation (LDA) and generalized gradient approximation (GGA). The structural properties, including lattice constants, bulk modulus and their pressure derivatives are in very good agreement with the available experimental and theoretical data. The calculations of the electronic band structure, density of states and charge density reveal that compounds are both ionic insulators. The optical properties (namely: the real and the imaginary parts of the dielectric function ɛ(ω), the refractive index n(ω) and the extinction coefficient k(ω)) were calculated for radiation up to 40.0 eV.

Correlation of electronic structure and magnetic moment in Ga1-xMnxN : First-principles, mean field and high temperature series expansions calculations

NASA Astrophysics Data System (ADS)

Masrour, R.; Hlil, E. K.

2016-08-01

Self-consistent ab initio calculations based on density-functional theory and using both full potential linearized augmented plane wave and Korring-Kohn-Rostoker-coherent potential approximation methods, are performed to investigate both electronic and magnetic properties of the Ga1-xMnxN system. Magnetic moments considered to lie along (001) axes are computed. Obtained data from ab initio calculations are used as input for the high temperature series expansions (HTSEs) calculations to compute other magnetic parameters such as the magnetic phase diagram and the critical exponent. The increasing of the dilution x in this system has allowed to verify a series of HTSEs predictions on the possibility of ferromagnetism in dilute magnetic insulators and to demonstrate that the interaction changes from antiferromagnetic to ferromagnetic passing through the spins glace phase.

Ab-initio study of double perovskite Ba2YSbO6

NASA Astrophysics Data System (ADS)

Mondal, Golak; Jha, D.; Himanshu, A. K.; Lahiri, J.; Singh, B. K.; Kumar, Uday; Ray, Rajyavardhan

2018-04-01

The density functional theory with generalized gradient approximation has been used to investigate the electronic structure of double perovskite oxide Ba2YSbO6 (BYS) synthesized in polycrystalline form by solid state reaction. Structural characterization of the compound was done through X-ray diffraction (XRD) followed by Riedvelt analysis of the XRD pattern. The crystal structure is cubic, space group being Fm-3m (No. 225) with the lattice parameter, a = 8.424 Å. Optical band-gap of this system has been calculated using UV-Vis Spectroscopy and Kubelka-Munk (KM) function, having the value 4.56eV. A detailed study of the electronic properties has also been carried out using the Full-Potential Linear Augmented Plane Wave (FPLAPW) as implemented in WIEN2k. BYS is found to be a large band-gap insulator with potential technological applications, such as dielectric resonators and filters in microwave applications.

The Impact and Implication of Peripheral Vascular Leakage on Ultra-Widefield Fluorescein Angiography in Uveitis.

PubMed

Thomas, Akshay S; Redd, Travis; Campbell, John P; Palejwala, Neal V; Baynham, Justin T; Suhler, Eric B; Rosenbaum, James T; Lin, Phoebe

2017-10-16

To study if peripheral vascular leakage (PVL) on ultra-widefield fluorescein angiography (UWFFA) prognosticates complications of uveitis or necessitates treatment augmentation. Retrospective cohort study of uveitis patients imaged with UWFFA and ≥1 yr of follow-up. We included 73 eyes of 42 patients with uveitis. There was no difference in baseline, intermediate, final visual acuity (p = 0.47-0.95) or rates of cystoid macular edema (CME) (p = 0.37-0.87) in eyes with PVL vs. those without. Eyes with PVL receiving baseline treatment augmentation were more likely to have baseline CME but were not more likely to have impaired visual acuity at final follow-up. PVL was independently associated with treatment augmentation on generalized estimating equation analysis with multivariable linear regression (OR: 4.39, p = 0.015). PVL did not confer an increased risk of impaired VA or CME at ≥1 yr follow-up but was possibly an independent driver of treatment augmentation.

Augmented reality application for industrial non-destructive inspection training

NASA Astrophysics Data System (ADS)

Amza, Catalin Gheorghe; Zapciu, Aurelian; Teodorescu, Octav

2018-02-01

Such a technology - Augmented Reality (AR) has great potential of use, especially for training purposes of new operators on using expensive equipment. In this context, the paper presents an augmented reality training system developed for phased-array ultrasonic non-destructive testing (NDT) equipment. The application has been developed using Unity 5.6.0 game-engine platform integrated with Vuforia sdk toolkit for devices with Android operating system. The test results performed by several NDT operators showed good results, thus proving the potential of using the application in the industrial field.

Augmented Learning: Research and Design of Mobile Educational Games

ERIC Educational Resources Information Center

Klopfer, Eric

2008-01-01

New technology has brought with it new tools for learning, and research has shown that the educational potential of video games resonates with scholars, teachers, and students alike. In "Augmented Learning", Eric Klopfer describes the largely untapped potential of mobile learning games--games played on such handheld devices as cell phones, Game…

First principles study of structural, electronic and optical properties of perovskites CaZrO3 and CaHfO3 in cubic phase

NASA Astrophysics Data System (ADS)

Hoat, D. M.; Silva, J. F. Rivas; Blas, A. Méndez

2018-07-01

In this work, we present the first principles calculations for structural, electronic and optical properties of perovskites CaZrO3 and CaHfO3 using the full-potential linearized augmented plane wave method (FP-LAPW) within the framework of density functional theory (DFT) as implemented in WIEN2k package. The exchange-correlation potential is treated with local density approximation (LDA) and generalized gradient approximation (GGA-PBE and PBESol). Additionally, the Tran Blaha modified Becke-Johnson exchange potential (mBJ) also is employed for electronic and optical calculations due to that it gives very accurate band gap of solids. Our obtained structural parameters are in good agreement with experimental datas and other theoretical results. The energy band gap obtained with mBJ is 4.56 eV for CaZrO3 and 5.27 eV for CaHfO3. The hybridization of states of O atom with those of Zr and Hf atoms in CaZrO3 and CaHfO3, respectively, is observed. The spin-orbit coupling effect on electronic properties of considered compounds also is investigated. Finally, the linear optical properties of CaZrO3 and CaHfO3 are derived from their complex dielectric function calculated with mBJ potential for wide energy range up to 45 eV, and all of them analyzed in details.

Analytic Morse/long-range potential energy surfaces and "adiabatic-hindered-rotor" treatment for a symmetric top-linear molecule dimer: A case study of CH3F-H2

NASA Astrophysics Data System (ADS)

Zhang, Xiao-Long; Ma, Yong-Tao; Zhai, Yu; Li, Hui

2018-03-01

A first effective six-dimensional ab initio potential energy surface (PES) for CH3F-H2 which explicitly includes the intramolecular Q3 stretching normal mode of the CH3F monomer is presented. The electronic structure computations have been carried out at the explicitly correlated coupled cluster level of theory [CCSD(T)-F12a] with an augmented correlation-consistent triple zeta basis set. Five-dimensional analytical intermolecular PESs for ν3(CH3F) = 0 and 1 are then obtained by fitting the vibrationally averaged potentials to the Morse/Long-Range (MLR) potential function form. The MLR function form is applied to the nonlinear molecule-linear molecule case for the first time. These fits to 25 015 points have root-mean-square deviations of 0.74 cm-1 and 0.082 cm-1 for interaction energies less than 0.0 cm-1. Using the adiabatic hindered-rotor approximation, three-dimensional PESs for CH3F-paraH2 are generated from the 5D PESs over all possible orientations of the hydrogen monomer. The infrared and microwave spectra for CH3F-paraH2 dimer are predicted for the first time. These analytic PESs can be used for modeling the dynamical behavior in CH3F-(H2)N clusters, including the possible appearance of microscopic superfluidity.

Comparison of closed loop model with flight test results

NASA Technical Reports Server (NTRS)

George, F. L.

1981-01-01

An analytic technique capable of predicting the landing characteristics of proposed aircraft configurations in the early stages of design was developed. In this analysis, a linear pilot-aircraft closed loop model was evaluated using experimental data generated with the NT-33 variable stability in-flight simulator. The pilot dynamics are modeled as inner and outer servo loop closures around aircraft pitch attitude, and altitude rate-of-change respectively. The landing flare maneuver is of particular interest as recent experience with military and other highly augmented vehicles shows this task to be relatively demanding, and potentially a critical design point. A unique feature of the pilot model is the incorporation of an internal model of the pilot's desired flight path for the flare maneuver.

Structural, electronic and magnetic properties of Pr-based filled skutterudites: A first principle study

NASA Astrophysics Data System (ADS)

Yadav, Priya; Nautiyal, Shashank; Verma, U. P.

2018-04-01

Ternary skutterudites materials exhibit good electronic properties due to the unpaired d- and f- electrons of the transition and rare-earth metals, respectively. In this communication, we have performed the structural optimization of Pr-based filled skutterudite (PrCo4P12) for the first time and obtained the electronic band structure, density of states and magnetic moments by using the full-potential linearized augmented plane wave (FP-LAPW) method based on density functional theory (DFT). Our obtained magnetic moment of PrCo4P12 is ˜ 1.8 µB in which main contribution is due to Pr atom. Behavior of this material is metallic and it is most stable in body centered cubic (BCC) structure.

Structural, Electronic and Elastic Properties of Half-Heusler Alloys CrNiZ (Z = Al, Si, Ge and As)

NASA Astrophysics Data System (ADS)

Zitouni, A.; Benstaali, W.; Abbad, A.; Lantri, T.; Bouadjemi, B.; Aziz, Z.

2018-06-01

In the present work, a self-consistent ab-initio calculation using the full- potential linearized augmented plane wave (FP-LAPW) method within the framework of the spin-polarized density functional theory (DFT) was used to study the structural, electronic, magnetic and elastic properties of the half Heusler alloys CrNiZ (Z = Al, Si, Ge and As) in three phases ( α, β and γ phases). The generalized gradient approximation (GGA) described by Perdew-Burke-Ernzerhof (PBE) was used. The results obtained for the spin-polarized band structure and the density of states show a halfmetallic behavior for the four compounds. The elastic constants ( C ij ) show that our compounds are ductile, stiff and anisotropic.

Electronic structure and properties of lanthanum

NASA Astrophysics Data System (ADS)

Nixon, Lane; Papaconstantopoulos, Dimitrios

2008-03-01

The total energy and electronic structure of lanthanum have been calculated in the bcc, fcc, hcp and dhcp structures for pressures up to 50 GPa. The full potential linearized-augmented-planewave method was used with both the local-density and general-gradient approximations. The correct phase ordering has been found, with lattice parameters and bulk moduli in good agreement with experimental data. The GGA method shows excellent agreement overall while the LDA results show larger discrepancies. The calculated strain energies for the fcc and bcc structures demonstrate the respective stable and unstable configurations at ambient conditions. The calculated superconductivity properties under pressure for the fcc structure are also found to agree well with measurements. Both LDA and GGA, with minor differences, reproduce well the experimental results for Tc.

The electronic structure and optical properties of ABP 2O 7 ( A = Na, Li) double phosphates

NASA Astrophysics Data System (ADS)

Hizhnyi, Yu. A.; Oliynyk, A.; Gomenyuk, O.; Nedilko, S. G.; Nagornyi, P.; Bojko, R.; Bojko, V.

2008-01-01

Partial densities of states and reflection spectra of NaAlP 2O 7, KAlP 2O 7 and LiInP 2O 7 double phosphate crystals are calculated by the full-potential linear-augmented-plane-wave (FLAPW) method. Experimental reflection spectra of KAlP 2O 7, CsAlP 2O 7 and NaInP 2O 7 are measured in the 4-20 eV energy range. The values of band gaps, Eg, are found from a comparison of experiment and calculations to be 6.0 eV for NaAlP 2O 7 and KAlP 2O 7, and 4.6 eV for LiInP 2O 7.

Linearized Alternating Direction Method of Multipliers for Constrained Nonconvex Regularized Optimization

DTIC Science & Technology

2016-11-22

structure of the graph, we replace the ℓ1- norm by the nonconvex Capped -ℓ1 norm , and obtain the Generalized Capped -ℓ1 regularized logistic regression...X. M. Yuan. Linearized augmented lagrangian and alternating direction methods for nuclear norm minimization. Mathematics of Computation, 82(281):301...better approximations of ℓ0- norm theoretically and computationally beyond ℓ1- norm , for example, the compressive sensing (Xiao et al., 2011). The

End-point controller design for an experimental two-link flexible manipulator using convex optimization

NASA Technical Reports Server (NTRS)

Oakley, Celia M.; Barratt, Craig H.

1990-01-01

Recent results in linear controller design are used to design an end-point controller for an experimental two-link flexible manipulator. A nominal 14-state linear-quadratic-Gaussian (LQG) controller was augmented with a 528-tap finite-impulse-response (FIR) filter designed using convex optimization techniques. The resulting 278-state controller produced improved end-point trajectory tracking and disturbance rejection in simulation and experimentally in real time.

Electronic and optical response of zirconium sulphoselenides: Compton spectroscopy and first-principles calculations

NASA Astrophysics Data System (ADS)

Kumar, Kishor; Bhatt, Samir; Jani, A. R.; Ahuja, B. L.

2015-12-01

We present the first-ever experimental Compton profiles (CPs) of ZrSSe2 and ZrS1.5Se1.5 using 100 mCi 241Am Compton spectrometer. To analyze the experimental momentum densities, we have computed for the first-time the CPs, energy bands and density of states using linear combination of atomic orbitals (LCAO) method. To model the exchange and correlation effects within LCAO approach, we have considered Hartree-Fock (HF), density functional theory (DFT) with revised functional of Perdew-Becke-Ernzerhof (PBEsol) and hybridization of HF and DFT. Going beyond computation of electronic properties using LCAO method, we have also derived electronic and optical properties using the modified Becke-Johnson (mBJ) potential within full potential linearized augmented plane wave (FP-LAPW) method. There is notable decrease in the energy band gap on replacing S by Se atoms in ZrSSe2 to obtain ZrS1.5Se1.5 composition, which is mainly attributed to readjustment of Zr-4d, S-3p and Se-4p states. It is seen that the CPs based on hybridization of HF and DFT show a better agreement with the experimental profiles than those based on individual HF and DFT-GGA-PBEsol schemes. The optical properties computed using FP-LAPW-mBJ method unambiguously depict feasibility of using both the sulphoselenides in photovoltaics and also utility of ZrS1.5Se1.5 in the field of non-linear optics.

Theoretical studies of potential energy surface and rotational spectra of Xe -H2O van der Waals complex

NASA Astrophysics Data System (ADS)

Wang, Lin; Yang, Minghui

2008-11-01

In this work we report an ab initio intermolecular potential energy surface and theoretical spectroscopic studies for Xe -H2O complex. The ab initio energies are calculated with CCSD(T) method and large basis sets (aug-cc-pVQZ for H and O and aug-cc-pVQZ-PP for Xe) augmented by a {3s3p2d2f1g} set of bond functions. This potential energy surface has a global minimum corresponding to a planar and nearly linear hydrogen bonded configuration with a well depth of 192.5cm-1 at intermolecular distance of 4.0Å, which is consistent with the previous determined potential by Wen and Jäger [J. Phys. Chem. A 110, 7560 (2006)]. The bound state calculations have been performed for the complex by approximating the water molecule as a rigid rotor. The theoretical rotational transition frequencies, isotopic shifts, nuclear quadrupole coupling constants, and structure parameters are in good agreement with the experimental observed values. The wavefunctions are analyzed to understand the dynamics of the ground and the first excited states.

Augmented Reality Tower Technology Assessment

NASA Technical Reports Server (NTRS)

Reisman, Ronald J.; Brown, David M.

2009-01-01

Augmented Reality technology may help improve Air Traffic Control Tower efficiency and safety during low-visibility conditions. This paper presents the assessments of five off-duty controllers who shadow-controlled' with an augmented reality prototype in their own facility. Initial studies indicated unanimous agreement that this technology is potentially beneficial, though the prototype used in the study was not adequate for operational use. Some controllers agreed that augmented reality technology improved situational awareness, had potential to benefit clearance, control, and coordination tasks and duties and could be very useful for acquiring aircraft and weather information, particularly aircraft location, heading, and identification. The strongest objections to the prototype used in this study were directed at aircraft registration errors, unacceptable optical transparency, insufficient display performance in sunlight, inadequate representation of the static environment and insufficient symbology.

Impacts of Integrating the Repertory Grid into an Augmented Reality-Based Learning Design on Students' Learning Achievements, Cognitive Load and Degree of Satisfaction

ERIC Educational Resources Information Center

Wu, Po-Han; Hwang, Gwo-Jen; Yang, Mei-Ling; Chen, Chih-Hung

2018-01-01

Augmented reality (AR) offers potential advantages for intensifying environmental context awareness and augmenting students' experiences in real-world environments by dynamically overlapping digital materials with a real-world environment. However, some challenges to AR learning environments have been described, such as participants' cognitive…

Augmented Reality, the Future of Contextual Mobile Learning

ERIC Educational Resources Information Center

Sungkur, Roopesh Kevin; Panchoo, Akshay; Bhoyroo, Nitisha Kirtee

2016-01-01

Purpose: This study aims to show the relevance of augmented reality (AR) in mobile learning for the 21st century. With AR, any real-world environment can be augmented by providing users with accurate digital overlays. AR is a promising technology that has the potential to encourage learners to explore learning materials from a totally new…

The role of replaceable and density-dependent mortality in assessing augmentative releases of Trichogramma in U.S. cotton

USDA-ARS?s Scientific Manuscript database

Although augmentation of Trichogramma wasps is rarely used in cotton production in the U.S., the insights gained from prior Trichogramma research in U.S. cotton provide insight on the potential of augmenting Trichogramma in other crops and production regions of the world. In this chapter, we provid...

A velocity command stepper motor for CSI application

NASA Technical Reports Server (NTRS)

Sulla, Jeffrey L.; Juang, Jer-Nan; Horta, Lucas G.

1991-01-01

The application of linear force actuators for vibration suppression of flexible structures has received much attention in recent years. A linear force actuator consists of a movable mass that is restrained such that its motion is linear. By application of a force to the mass, an equal and opposite reaction force can be applied to a structure. The use of an industrial linear stepper motor as a reaction mass actuator is described. With the linear stepper motor mounted on a simple test beam and the NASA Mini-Mast, output feedback of acceleration or displacement are used to augment the structural damping of the test articles. Significant increases in damping were obtained for both the test beam and the Mini-Mast.

A linear quadratic regulator approach to the stabilization of uncertain linear systems

NASA Technical Reports Server (NTRS)

Shieh, L. S.; Sunkel, J. W.; Wang, Y. J.

1990-01-01

This paper presents a linear quadratic regulator approach to the stabilization of uncertain linear systems. The uncertain systems under consideration are described by state equations with the presence of time-varying unknown-but-bounded uncertainty matrices. The method is based on linear quadratic regulator (LQR) theory and Liapunov stability theory. The robust stabilizing control law for a given uncertain system can be easily constructed from the symmetric positive-definite solution of the associated augmented Riccati equation. The proposed approach can be applied to matched and/or mismatched systems with uncertainty matrices in which only their matrix norms are bounded by some prescribed values and/or their entries are bounded by some prescribed constraint sets. Several numerical examples are presented to illustrate the results.

Entrainment and thrust augmentation in pulsatile ejector flows

NASA Technical Reports Server (NTRS)

Sarohia, V.; Bernal, L.; Bui, T.

1981-01-01

This study comprised direct thrust measurements, flow visualization by use of a spark shadowgraph technique, and mean and fluctuating velocity measurements with a pitot tube and linearized constant temperature hot-wire anemometry respectively. A gain in thrust of as much as 10 to 15% was observed for the pulsatile ejector flow as compared to the steady flow configuration. From the velocity profile measurements, it is concluded that this enhanced augmentation for pulsatile flow as compared to a nonpulsatile one was accomplished by a corresponding increased entrainment by the primary jet flow. It is also concluded that the augmentation and total entrainment by a constant area ejector critically depends upon the inlet geometry of the ejector. Experiments were performed to evaluate the influence of primary jet to ejector area ratio, ejector length, and presence of a diffuser on pulsatile ejector performance.

Operationally efficient propulsion system study (OEPSS) data book. Volume 10; Air Augmented Rocket Afterburning

NASA Technical Reports Server (NTRS)

Farhangi, Shahram; Trent, Donnie (Editor)

1992-01-01

A study was directed towards assessing viability and effectiveness of an air augmented ejector/rocket. Successful thrust augmentation could potentially reduce a multi-stage vehicle to a single stage-to-orbit vehicle (SSTO) and, thereby, eliminate the associated ground support facility infrastructure and ground processing required by the eliminated stage. The results of this preliminary study indicate that an air augmented ejector/rocket propulsion system is viable. However, uncertainties resulting from simplified approach and assumptions must be resolved by further investigations.

Augmentation with an ovine forestomach matrix scaffold improves histological outcomes of rotator cuff repair in a rat model.

PubMed

Street, Matthew; Thambyah, Ashvin; Dray, Michael; Amirapu, Satya; Tuari, Donna; Callon, Karen E; McIntosh, Julie D; Burkert, Kristina; Dunbar, P Rod; Coleman, Brendan; Cornish, Jillian; Musson, David S

2015-10-20

Rotator cuff tears can cause significant pain and functional impairment. Without surgical repair, the rotator cuff has little healing potential, and following surgical repair, they are highly prone to re-rupture. Augmenting such repairs with a biomaterial scaffold has been suggested as a potential solution. Extracellular matrix (ECM)-based scaffolds are the most commonly used rotator cuff augments, although to date, reports on their success are variable. Here, we utilize pre-clinical in vitro and in vivo assays to assess the efficacy of a novel biomaterial scaffold, ovine forestomach extracellular matrix (OFM), in augmenting rotator cuff repair. OFM was assessed in vitro for primary tenocyte growth and adherence, and for immunogenicity using an assay of primary human dendritic cell activation. In vivo, using a murine model, supraspinatus tendon repairs were carried out in 34 animals. Augmentation with OFM was compared to sham surgery and unaugmented control. At 6- and 12-week time points, the repairs were analysed biomechanically for strength of repair and histologically for quality of healing. OFM supported tenocyte growth in vitro and did not cause an immunogenic response. Augmentation with OFM improved the quality of healing of the repaired tendon, with no evidence of excessive inflammatory response. However, there was no biomechanical advantage of augmentation. The ideal rotator cuff tendon augment has not yet been identified or clinically implemented. ECM scaffolds offer a promising solution to a difficult clinical problem. Here, we have shown improved histological healing with OFM augmentation. Identifying materials that offset the poorer mechanical properties of the rotator cuff post-injury/repair and enhance organised tendon healing will be paramount to incorporating augmentation into surgical treatment of the rotator cuff.

A sequential linear optimization approach for controller design

NASA Technical Reports Server (NTRS)

Horta, L. G.; Juang, J.-N.; Junkins, J. L.

1985-01-01

A linear optimization approach with a simple real arithmetic algorithm is presented for reliable controller design and vibration suppression of flexible structures. Using first order sensitivity of the system eigenvalues with respect to the design parameters in conjunction with a continuation procedure, the method converts a nonlinear optimization problem into a maximization problem with linear inequality constraints. The method of linear programming is then applied to solve the converted linear optimization problem. The general efficiency of the linear programming approach allows the method to handle structural optimization problems with a large number of inequality constraints on the design vector. The method is demonstrated using a truss beam finite element model for the optimal sizing and placement of active/passive-structural members for damping augmentation. Results using both the sequential linear optimization approach and nonlinear optimization are presented and compared. The insensitivity to initial conditions of the linear optimization approach is also demonstrated.

Augmented Reality in Education--Cases, Places and Potentials

ERIC Educational Resources Information Center

Bower, Matt; Howe, Cathie; McCredie, Nerida; Robinson, Austin; Grover, David

2014-01-01

Augmented Reality is poised to profoundly transform Education as we know it. The capacity to overlay rich media onto the real world for viewing through web-enabled devices such as phones and tablet devices means that information can be made available to students at the exact time and place of need. This has the potential to reduce cognitive…

Fixed order dynamic compensation for multivariable linear systems

NASA Technical Reports Server (NTRS)

Kramer, F. S.; Calise, A. J.

1986-01-01

This paper considers the design of fixed order dynamic compensators for multivariable time invariant linear systems, minimizing a linear quadratic performance cost functional. Attention is given to robustness issues in terms of multivariable frequency domain specifications. An output feedback formulation is adopted by suitably augmenting the system description to include the compensator states. Either a controller or observer canonical form is imposed on the compensator description to reduce the number of free parameters to its minimal number. The internal structure of the compensator is prespecified by assigning a set of ascending feedback invariant indices, thus forming a Brunovsky structure for the nominal compensator.

Normative Data for Interpreting the BREAST-Q: Augmentation

PubMed Central

Mundy, Lily R.; Homa, Karen; Klassen, Anne F.; Pusic, Andrea L.; Kerrigan, Carolyn L.

2016-01-01

Background The BREAST-Q is a rigorously developed, well-validated, patient-reported outcome (PRO) instrument with a module designed for evaluating breast augmentation outcomes. However, there are no published normative BREAST-Q scores, limiting interpretation. Methods Normative data were generated for the BREAST-Q Augmentation Module via the Army of Women (AOW), an online community of women (with and without breast cancer) engaged in breast-cancer related research. Members were recruited via email, with women 18 years or older without a history of breast cancer or breast surgery invited to participate. Descriptive statistics and a linear multivariate regression were performed. A separate analysis compared normative scores to findings from previously published BREAST-Q augmentation studies. Results The preoperative BREAST-Q Augmentation Module was completed by 1,211 women. Mean age was 54 ±24 years, mean body mass index (BMI) was 27 ±6, and 39% (n=467) had a bra cup size ≥D. Mean scores were Satisfaction with Breasts (54 ±19), Psychosocial Well-being (66 ±20), Sexual Well-being (49 ±20), and Physical Well-being (86 ±15). Women with a BMI of 30 or greater and bra cup size D or greater had lower scores. In comparison to AOW scores, published BREAST-Q augmentation scores were lower before and higher after surgery for all scales except Physical Well-being. Conclusions The AOW normative data represent breast-related satisfaction and well-being in woman not actively seeking breast augmentation. This data may be used as normative comparison values for those seeking and undergoing surgery as we did, demonstrating the value of breast augmentation in this patient population. PMID:28350657

Augmented potential, energy densities, and virial relations in the weak- and strong-interaction limits of DFT

NASA Astrophysics Data System (ADS)

Vuckovic, Stefan; Levy, Mel; Gori-Giorgi, Paola

2017-12-01

The augmented potential introduced by Levy and Zahariev [Phys. Rev. Lett. 113, 113002 (2014)] is shifted with respect to the standard exchange-correlation potential of the Kohn-Sham density functional theory by a density-dependent constant that makes the total energy become equal to the sum of the occupied orbital energies. In this work, we analyze several features of this approach, focusing on the limit of infinite coupling strength and studying the shift and the corresponding energy density at different correlation regimes. We present and discuss coordinate scaling properties of the augmented potential, study its connection to the response potential, and use the shift to analyze the classical jellium and uniform gas models. We also study other definitions of the energy densities in relation to the functional construction by local interpolations along the adiabatic connection. Our findings indicate that the energy density that is defined in terms of the electrostatic potential of the exchange-correlation hole is particularly well suited for this purpose.

Control-Volume Analysis Of Thrust-Augmenting Ejectors

NASA Technical Reports Server (NTRS)

Drummond, Colin K.

1990-01-01

New method of analysis of transient flow in thrust-augmenting ejector based on control-volume formulation of governing equations. Considered as potential elements of propulsion subsystems of short-takeoff/vertical-landing airplanes.

Strategies and Challenges in Simultaneous Augmentation Mastopexy.

PubMed

Spring, Michelle A; Hartmann, Emily C; Stevens, W Grant

2015-10-01

Simultaneous breast augmentation and mastopexy is a common procedure often considered to be one of the most difficult cosmetic breast surgeries. One-stage augmentation mastopexy was initially described more than 50 years ago. The challenge lies in the fact that the surgery has multiple opposing goals: to increasing the volume of a breast, enhance the shape, and simultaneously decrease the skin envelope. Successful outcomes in augmentation can be expected with proper planning, technique, and patient education. This article focuses on common indications for simultaneous augmentation mastopexy, techniques for safe and effective combined procedures, challenges of the procedure, and potential complications. Copyright © 2015 Elsevier Inc. All rights reserved.

Augmentation of linear facial anthropometrics through modern morphometrics: a facial convexity example.

PubMed

Wei, R; Claes, P; Walters, M; Wholley, C; Clement, J G

2011-06-01

The facial region has traditionally been quantified using linear anthropometrics. These are well established in dentistry, but require expertise to be used effectively. The aim of this study was to augment the utility of linear anthropometrics by applying them in conjunction with modern 3-D morphometrics. Facial images of 75 males and 94 females aged 18-25 years with self-reported Caucasian ancestry were used. An anthropometric mask was applied to establish corresponding quasi-landmarks on the images in the dataset. A statistical face-space, encoding shape covariation, was established. The facial median plane was extracted facilitating both manual and automated indication of commonly used midline landmarks. From both indications, facial convexity angles were calculated and compared. The angles were related to the face-space using a regression based pathway enabling the visualization of facial form associated with convexity variation. Good agreement between the manual and automated angles was found (Pearson correlation: 0.9478-0.9474, Dahlberg root mean squared error: 1.15°-1.24°). The population mean angle was 166.59°-166.29° (SD 5.09°-5.2°) for males-females. The angle-pathway provided valuable feedback. Linear facial anthropometrics can be extended when used in combination with a face-space derived from 3-D scans and the exploration of property pathways inferred in a statistically verifiable way. © 2011 Australian Dental Association.

Feature Augmentation via Nonparametrics and Selection (FANS) in High-Dimensional Classification.

PubMed

Fan, Jianqing; Feng, Yang; Jiang, Jiancheng; Tong, Xin

We propose a high dimensional classification method that involves nonparametric feature augmentation. Knowing that marginal density ratios are the most powerful univariate classifiers, we use the ratio estimates to transform the original feature measurements. Subsequently, penalized logistic regression is invoked, taking as input the newly transformed or augmented features. This procedure trains models equipped with local complexity and global simplicity, thereby avoiding the curse of dimensionality while creating a flexible nonlinear decision boundary. The resulting method is called Feature Augmentation via Nonparametrics and Selection (FANS). We motivate FANS by generalizing the Naive Bayes model, writing the log ratio of joint densities as a linear combination of those of marginal densities. It is related to generalized additive models, but has better interpretability and computability. Risk bounds are developed for FANS. In numerical analysis, FANS is compared with competing methods, so as to provide a guideline on its best application domain. Real data analysis demonstrates that FANS performs very competitively on benchmark email spam and gene expression data sets. Moreover, FANS is implemented by an extremely fast algorithm through parallel computing.

Feature Augmentation via Nonparametrics and Selection (FANS) in High-Dimensional Classification

PubMed Central

Feng, Yang; Jiang, Jiancheng; Tong, Xin

2015-01-01

We propose a high dimensional classification method that involves nonparametric feature augmentation. Knowing that marginal density ratios are the most powerful univariate classifiers, we use the ratio estimates to transform the original feature measurements. Subsequently, penalized logistic regression is invoked, taking as input the newly transformed or augmented features. This procedure trains models equipped with local complexity and global simplicity, thereby avoiding the curse of dimensionality while creating a flexible nonlinear decision boundary. The resulting method is called Feature Augmentation via Nonparametrics and Selection (FANS). We motivate FANS by generalizing the Naive Bayes model, writing the log ratio of joint densities as a linear combination of those of marginal densities. It is related to generalized additive models, but has better interpretability and computability. Risk bounds are developed for FANS. In numerical analysis, FANS is compared with competing methods, so as to provide a guideline on its best application domain. Real data analysis demonstrates that FANS performs very competitively on benchmark email spam and gene expression data sets. Moreover, FANS is implemented by an extremely fast algorithm through parallel computing. PMID:27185970

Three-dimensional analysis of bone remodeling following ridge augmentation of compromised extraction sockets in periodontitis patients: A randomized controlled study.

PubMed

Aimetti, Mario; Manavella, Valeria; Corano, Lisa; Ercoli, Elena; Bignardi, Cristina; Romano, Federica

2018-02-01

The aim of this study was to analyze linear and volumetric hard tissue changes in severely resorbed alveolar sockets after ridge augmentation procedure and to compare them with spontaneous healing using three-dimensional cone beam computed tomography (CBCT). Thirty patients (mean age 53.2 ± 6.3 years) requiring tooth extraction for advanced periodontitis were randomly allocated to test and control groups. The test sites were grafted using a collagenated bovine-derived bone (DBBM-C) covered with a collagen membrane, while control sites had spontaneous healing. Both groups healed by secondary intention. Linear and volumetric measurements were taken on superimposed CBCT images obtained after tooth extraction and 12 months later. Greater horizontal shrinkage, localized mainly in the crestal zone, was observed in the control group (4.92 ± 2.45 mm) compared to the test group (2.60 ± 1.24 mm). While both groups presented a rebuilding of the buccal wall, it was most pronounced in the grafted sockets (2.50 ± 2.12 mm vs. 0.51 ± 1.02 mm). A significant difference was also registered in the percentage of volume loss between grafted and non-grafted sites (9.14% vs. 35.16%, p-value <.0001). Alveolar sockets with extensive buccal bone deficiencies undergo significant three-dimensional volumetric alterations following natural healing. The immediate application of a slow-resorbing xenograft with a covering collagen membrane seems to be effective in improving alveolar ridge shape and dimensions, thus potentially reducing the need for adjunctive regenerative procedures at the time of implant placement. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Exploring the Potential of a Location Based Augmented Reality Game for Language Learning

ERIC Educational Resources Information Center

Richardson, Donald

2016-01-01

This paper adds to the small but growing body of research into the potential of augmented reality games for teaching and learning English as a foreign language (EFL). It explores the extent to which such games enhance the language learning experience of advanced level EFL learners. The author draws on his work developing "Mission not really…

Vertical augmentation of the posterior atrophic mandible by interpositional grafts in a split-mouth design: a human tomography evaluation pilot study.

PubMed

Domingues, Eduardo Pinheiro; Ribeiro, Rafael Fernandes; Horta, Martinho Campolina Rebello; Manzi, Flávio Ricardo; Côsso, Maurício Greco; Zenóbio, Elton Gonçalves

2017-10-01

Using computed tomography, to compare vertical and volumetric bone augmentation after interposition grafting with bovine bone mineral matrix (GEISTLICH BIO-OSS ® ) or hydroxyapatite/tricalcium phosphate (STRAUMANN ® BONECERAMIC) for atrophic posterior mandible reconstruction through segmental osteotomy. Seven patients received interposition grafts in the posterior mandible for implant rehabilitation. The computed tomography cone beam images were analysed with OsiriX Imaging Software 6.5 (Pixmeo Geneva, Switzerland) in the pre-surgical period (T0), at 15 days post-surgery (T1) and at 180 days post-surgery (T2). The tomographic analysis was performed by a single trained and calibrated radiologist. Descriptive statistics and nonparametric methods were used to analyse the data. There was a significant difference in vertical and volume augmentation with both biomaterials using the technique (P < 0.05). There were no significant differences (P > 0.05) in volume change of the graft, bone volume augmentation, or augmentation of the maximum linear vertical distance between the two analysed biomaterials. The GEISTLICH BIO-OSS ® and STRAUMANN ® BONECERAMIC interposition grafts exhibited similar and sufficient dimensional stability and volume gain for short implants in the atrophic posterior mandible. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Augmented reality: a review.

PubMed

Berryman, Donna R

2012-01-01

Augmented reality is a technology that overlays digital information on objects or places in the real world for the purpose of enhancing the user experience. It is not virtual reality, that is, the technology that creates a totally digital or computer created environment. Augmented reality, with its ability to combine reality and digital information, is being studied and implemented in medicine, marketing, museums, fashion, and numerous other areas. This article presents an overview of augmented reality, discussing what it is, how it works, its current implementations, and its potential impact on libraries.

Actuation Using Piezoelectric Materials: Application in Augmenters, Energy Harvesters, and Motors

NASA Technical Reports Server (NTRS)

Hasenoehrl, Jennifer

2012-01-01

Piezoelectric actuators are used in many manipulation, movement, and mobility applications as well as transducers and sensors. When used at the resonance frequencies of the piezoelectric stack, the actuator performs at its maximum actuation capability. In this Space Grant internship, three applications of piezoelectric actuators were investigated including hammering augmenters of rotary drills, energy harvesters, and piezo-motors. The augmenter shows improved drill performance over rotation only. The energy harvesters rely on moving fluid to convert mechanical energy into electrical power. Specific designs allow the harvesters more freedom to move, which creates more power. The motor uses the linear movement of the actuator with a horn applied to the side of a rotor to create rotational motion. Friction inhibits this motion and is to be minimized for best performance. Tests and measurements were made during this internship to determine the requirements for optimal performance of the studied mechanisms and devices.

Ab initio study of the Coulomb interaction in NbxCo clusters: Strong on-site versus weak nonlocal screening

NASA Astrophysics Data System (ADS)

Peters, L.; Şaşıoǧlu, E.; Mertig, I.; Katsnelson, M. I.

2018-01-01

By means of ab initio calculations in conjunction with the random-phase approximation (RPA) within the full-potential linearized augmented plane wave method, we study the screening of the Coulomb interaction in NbxCo (1 ≤x ≤9 ) clusters. In addition, these results are compared with pure bcc Nb bulk. We find that for all clusters the on-site Coulomb interaction in RPA is strongly screened, whereas the intersite nonlocal Coulomb interaction is weakly screened and for some clusters it is unscreened or even antiscreened. This is in strong contrast with pure Nb bulk, where the intersite Coulomb interaction is almost completely screened. Furthermore, constrained RPA calculations reveal that the contribution of the Co 3 d → 3 d channel to the total screening of the Co 3 d electrons is small. Moreover, we find that both the on-site and intersite Coulomb interaction parameters decrease in a reasonable approximation linearly with the cluster size and for clusters having more than 20 Nb atoms a transition from 0D to 3D screening is expected to take place.

Augmented reality in neurosurgery

PubMed Central

Tagaytayan, Raniel; Kelemen, Arpad

2016-01-01

Neurosurgery is a medical specialty that relies heavily on imaging. The use of computed tomography and magnetic resonance images during preoperative planning and intraoperative surgical navigation is vital to the success of the surgery and positive patient outcome. Augmented reality application in neurosurgery has the potential to revolutionize and change the way neurosurgeons plan and perform surgical procedures in the future. Augmented reality technology is currently commercially available for neurosurgery for simulation and training. However, the use of augmented reality in the clinical setting is still in its infancy. Researchers are now testing augmented reality system prototypes to determine and address the barriers and limitations of the technology before it can be widely accepted and used in the clinical setting. PMID:29765445

Augmented reality in neurosurgery.

PubMed

Tagaytayan, Raniel; Kelemen, Arpad; Sik-Lanyi, Cecilia

2018-04-01

Neurosurgery is a medical specialty that relies heavily on imaging. The use of computed tomography and magnetic resonance images during preoperative planning and intraoperative surgical navigation is vital to the success of the surgery and positive patient outcome. Augmented reality application in neurosurgery has the potential to revolutionize and change the way neurosurgeons plan and perform surgical procedures in the future. Augmented reality technology is currently commercially available for neurosurgery for simulation and training. However, the use of augmented reality in the clinical setting is still in its infancy. Researchers are now testing augmented reality system prototypes to determine and address the barriers and limitations of the technology before it can be widely accepted and used in the clinical setting.

First principles predictions of electronic and elastic properties of BaPb2As2 in the ThCr2Si2-type structure

NASA Astrophysics Data System (ADS)

Bourourou, Y.; Amari, S.; Yahiaoui, I. E.; Bouhafs, B.

2018-01-01

A first-principles approach is used to predicts the electronic and elastic properties of BaPb2As2 superconductor compound, using full-potential linearized augmented plane wave plus local orbitals (FP-L/APW+lo) scheme within the local density approximation LDA. The calculated equilibrium structural parameter a agree well with the experiment while the c/a ratio is far away from the experimental result. The band structure, density of states, together with the charge density and chemical bonding are discussed. The calculated elastic constants for our compound indicate that it is mechanically stable at ambient pressure. Polycrystalline elastic moduli (Young's, Bulk, shear Modulus and the Poisson's ratio) were calculated according to the Voigte-Reusse-Hill (VRH) average.

Structural, elastic and electronic properties of transition metal carbides ZnC, NbC and their ternary alloys ZnxNb1-xC

NASA Astrophysics Data System (ADS)

Zidi, Y.; Méçabih, S.; Abbar, B.; Amari, S.

2018-02-01

We have investigated the structural, electronic and elastic properties of transition-metal carbides ZnxNb1-xC alloys in the range of 0 ≤ x ≤ 1 using the density functional theory (DFT). The full potential linearized augmented plane wave (FP-LAPW) method within a framework of the generalized gradient approximation (GGA) and GGA + U (where U is the Hubbard correlation terms) approach is used to perform the calculations presented here. The lattice parameters, the bulk modulus, its pressure derivative and the elastic constants were determined. We have obtained Young's modulus, shear modulus, Poisson's ratio, anisotropy factor by the aid of the calculated elastic constants. We discuss the total and partial densities of states and charge densities.

Ab - initio study of rare earth magnesium alloy: TbMg

NASA Astrophysics Data System (ADS)

Kumari, Meena; Yadav, Priya; Nautiyal, Shashank; Verma, U. P.

2018-05-01

The structural, electronic and magnetic properties of TbMg were analyzed by using full-potential linearized augmented plane wave method. This intermetallic is stable in structure CsCl (B2 phase) with space group Pm-3m. In electronic properties, we show the electronic band structure and density of states plots. These plots show that this alloy have metallic character because there is no band gap between the valance band and conduction band at Fermi level. The structural properties, i.e. equilibrium lattice constant, bulk modulus and its pressure derivative, energy and volume show good agreement with available data. In this paper, we also present the total magnetic moment along with the magnetic moment on the atomic and interstitial sites of TbMg intermetallic in B2 phase.

Effects of hydrostatic pressure on the thermoelectric properties of the ɛ-polytype of InSe, GaSe, and InGaSe2 semiconductor compounds: an ab initio study

NASA Astrophysics Data System (ADS)

Elsayed, H.; Olguín, D.; Cantarero, A.

2017-12-01

This work presents an ab initio study of the effects of hydrostatic pressure on the Seebeck coefficients and thermoelectric power factors of the ɛ-polytype of InSe, GaSe, and InGaSe2 semiconductor compounds. Our study is performed using the semi-classical Boltzmann theory and the rigid band approach. The electronic band structures of these materials are calculated using the full-potential linearized augmented plane-wave method. The obtained thermoelectric properties are discussed in terms of the results of the electronic structure calculations. As we will show, our calculated Seebeck coefficient values indicate that these materials are good alternatives to other well-studied thermoelectric systems.

Realizing the potential of the Actinium-225 radionuclide generator in targeted alpha-particle therapy applications

PubMed Central

Miederer, Matthias; Scheinberg, David A.; McDevitt, Michael R.

2013-01-01

Alpha particle-emitting isotopes have been proposed as novel cytotoxic agents for augmenting targeted therapy. Properties of alpha particle radiation such as their limited range in tissue of a few cell diameters and their high linear energy transfer leading to dense radiation damage along each alpha track are promising in the treatment of cancer, especially when single cells or clusters of tumor cells are targeted. Actinium-225 (225Ac) is an alpha particle-emitting radionuclide that generates 4 net alpha particle isotopes in a short decay chain to stable 209Bi, and as such can be described as an alpha particle nanogenerator. This article reviews the literature pertaining to the research, development, and utilization of targeted 225Ac to potently and specifically affect cancer. PMID:18514364

Augmented Reality Simulations on Handheld Computers

ERIC Educational Resources Information Center

Squire, Kurt; Klopfer, Eric

2007-01-01

Advancements in handheld computing, particularly its portability, social interactivity, context sensitivity, connectivity, and individuality, open new opportunities for immersive learning environments. This article articulates the pedagogical potential of augmented reality simulations in environmental engineering education by immersing students in…

Non-fragile multivariable PID controller design via system augmentation

NASA Astrophysics Data System (ADS)

Liu, Jinrong; Lam, James; Shen, Mouquan; Shu, Zhan

2017-07-01

In this paper, the issue of designing non-fragile H∞ multivariable proportional-integral-derivative (PID) controllers with derivative filters is investigated. In order to obtain the controller gains, the original system is associated with an extended system such that the PID controller design can be formulated as a static output-feedback control problem. By taking the system augmentation approach, the conditions with slack matrices for solving the non-fragile H∞ multivariable PID controller gains are established. Based on the results, linear matrix inequality -based iterative algorithms are provided to compute the controller gains. Simulations are conducted to verify the effectiveness of the proposed approaches.

Density functional theory calculations of the water interactions with ZrO2 nanoparticles Y2O3 doped

NASA Astrophysics Data System (ADS)

Subhoni, Mekhrdod; Kholmurodov, Kholmirzo; Doroshkevich, Aleksandr; Asgerov, Elmar; Yamamoto, Tomoyuki; Lyubchyk, Andrei; Almasan, Valer; Madadzada, Afag

2018-03-01

Development of a new electricity generation techniques is one of the most relevant tasks, especially nowadays under conditions of extreme growth in energy consumption. The exothermic heterogeneous electrochemical energy conversion to the electric energy through interaction of the ZrO2 based nanopowder system with atmospheric moisture is one of the ways of electric energy obtaining. The questions of conversion into the electric form of the energy of water molecules adsorption in 3 mol% Y2O3 doped ZrO2 nanopowder systems were investigated using the density functional theory calculations. The density functional theory calculations has been realized as in the Kohn-Sham formulation, where the exchange-correlation potential is approximated by a functional of the electronic density. The electronic density, total energy and band structure calculations are carried out using the all-electron, full potential, linear augmented plane wave method of the electronic density and related approximations, i.e. the local density, the generalized gradient and their hybrid approximations.

First-principles investigation for some physical properties of some fluoroperovskites compounds ABF3 (A = K, Na; B = Mg, Zn)

NASA Astrophysics Data System (ADS)

Bakri, Badis; Driss, Zied; Berri, Saadi; Khenata, Rabah

2017-12-01

In this work, the structural, electronic and optical properties of fluoroperovskite ABF3 (A = K, Na; B = Mg, Zn) were studied using two different approaches: the full-potential linearized augmented plane wave method and the pseudo-potential plane wave scheme in the frame of generalized gradient approximation features such as the lattice constant, bulk modulus and its pressure derivative are reported. The ground state properties of these compounds such as the equilibrium lattice constant and the bulk modulus are in good agreement with the experimental results. The first principles calculations were performed to study the electronic structures of ABF3(A = K, Na; B = Mg, Zn) compounds and the results indicated that these four compounds are indirect band gap insulators. The optical properties are analysed and the source of some peaks in the spectra is discussed. Besides, the dielectric function, refractive index and extinction coefficient for radiation up to 25 eV have also been reported and discussed.

Electric-field-induced modification in Dzyaloshinskii-Moriya interaction of Co monolayer on Pt(111)

NASA Astrophysics Data System (ADS)

Nakamura, Kohji; Akiyama, Toru; Ito, Tomonori; Ono, Teruo; Weinert, Michael

Magnetism induced by an external electric field (E-field) has received much attention as a potential approach for controlling magnetism at the nano-scale with the promise of ultra-low energy power consumption. Here, the E-field-induced modification of the Dzyaloshinskii-Moriya interaction (DMI) for a prototypical transition-metal thin layer of a Co monolayer on Pt(111) is investigated by first-principles calculations by using the full-potential linearized augmented plane wave method that treats spin-spiral structures in an E-field. With inclusion of the spin-orbit coupling (SOC) by the second variational method for commensurate spin-spiral structures, the DMI constants were estimated from an asymmetric contribution in the total energy with respect to the spin-spiral wavevector. The results predicted that the DMI is modified by the E-field, but the change is found to be small compared to that in the exchange interaction (a symmetric contribution in the total energy) by a factor of ten.

Electric-field-induced modification in Curie temperature of Co monolayer on Pt(111)

NASA Astrophysics Data System (ADS)

Nakamura, Kohji; Oba, Mikito; Akiyama, Toru; Ito, Tomonori; Weinert, Michael

2015-03-01

Magnetism induced by an external electric field (E-field) has received much attention as a potential approach for controlling magnetism at the nano-scale with the promise of ultra-low energy power consumption. Here, the E-field-induced modification of the Curie temperature for a prototypical transition-metal thin layer of a Co monolayer on Pt(111) is investigated by first-principles calculations by using the full-potential linearized augmented plane wave method that treats spin-spiral structures in an E-field. An applied E-field modifies the magnon (spin-spiral formation) energies by a few meV, which leads to a modification of the exchange pair interaction parameters within the classical Heisenberg model. With inclusion of the spin-orbit coupling (SOC), the magnetocrystalline anisotropy and the Dzyaloshinskii-Morita interaction are obtained by the second variation SOC method. An E-field-induced modification of the Curie temperature is demonstrated by Monte Carlo simulations, in which a change in the exchange interaction is found to play a key role.

The ab initio Calculation of Electric Field Gradient at the Site of P Impurity in α-Al3O2

NASA Astrophysics Data System (ADS)

Zhang, Qiao-Li; Yuan, Da-Qing; Zhang, Huan-Qiao; Fan, Ping; Zuo, Yi; Zheng, Yong-Nan; Masuta, K.; Fukuda, M.; Mihara, M.; Minamisono, T.; Kitagawa, A.; Zhu, Sheng-Yun

2012-09-01

An ab initio calculation of the electric-field gradient (EFG) at the site of a phosphorous impurity substituting an Al atom in α-Al2O3 is carried out using the WIEN2k code with the full-potential linearized augmented plane wave plus local orbital method (LAPW+lo) in the frame of density functional theory. The atomic lattice relaxations caused by the implanted impurities were calculated for two different charged states to well describe the electronic structure of the doped system. The EFG at the site of the phosphorous impurity in the charged supercell calculated with the exchange-correlation potential of the Wu-Cohen generalized gradient approximation (WC-GGA) is 0.573 × 1021 V/m2. Then, the nuclear quadrupole moment of the I = 3 state in 28P is deduced to be 137 mb from the quadrupole interaction frequency of 190 kHz measured recently by the β-NQR method.

Automatically augmenting lifelog events using pervasively generated content from millions of people.

PubMed

Doherty, Aiden R; Smeaton, Alan F

2010-01-01

In sensor research we take advantage of additional contextual sensor information to disambiguate potentially erroneous sensor readings or to make better informed decisions on a single sensor's output. This use of additional information reinforces, validates, semantically enriches, and augments sensed data. Lifelog data is challenging to augment, as it tracks one's life with many images including the places they go, making it non-trivial to find associated sources of information. We investigate realising the goal of pervasive user-generated content based on sensors, by augmenting passive visual lifelogs with "Web 2.0" content collected by millions of other individuals.

Curcumin augments the cytostatic and anti-invasive effects of mitoxantrone on carcinosarcoma cells in vitro.

PubMed

Luty, Marcin; Kwiecień, Edyta; Firlej, Magdalena; Łabędź-Masłowska, Anna; Paw, Milena; Madeja, Zbigniew; Czyż, Jarosław

2016-01-01

Numerous adverse effects limit the applicability of mitoxantrone for the treatment of drug-resistant tumors, including carcinosarcoma. Here, we estimated the additive effects of mitoxantrone and curcumin, a plant-derived biomolecule isolated from Curcuma longa, on the neoplastic and invasive potential of carcinosarcoma cells in vitro. Curcumin augmented the cytostatic, cytotoxic and anti-invasive effects of mitoxantrone on the Walker-256 cells. It also strengthened the inhibitory effects of mitoxantrone on the motility of drug-resistant Walker-256 cells that had retained viability after a long-term mitoxantrone/curcumin treatment. Thus, curcumin reduces the effective doses of mitoxantrone and augments its interference with the invasive potential of drug-resistant carcinosarcoma cells.

Comorbid symptomatology moderates response to risperidone, stimulant, and parent training in children with severe aggression, disruptive behavior disorder, and attention-deficit/hyperactivity disorder.

PubMed

Farmer, Cristan A; Brown, Nicole V; Gadow, Kenneth D; Arnold, L Eugene; Kolko, David G; Findling, Robert L; Molina, Brooke S G; Buchan-Page, Kristin A; Rice, Robert R; Bangalore, Srihari S; Bukstein, Oscar; Rundberg-Rivera, E Victoria; McNamara, Nora; Aman, Michael G

2015-04-01

In this study, we evaluated parent and child characteristics as predictors and moderators of response in the four-site Treatment of Severe Childhood Aggression (TOSCA) study. A total of 168 children with severe aggression, disruptive behavior disorder, and attention-deficit/hyperactivity disorder (ADHD) were enrolled in a 9-week trial of basic treatment (n=84, stimulant+parent training+placebo) versus augmented treatment (n=84, stimulant+parent training+risperidone). In the initial report, augmented treatment surpassed basic treatment in reducing the primary outcome of disruptive behavior (D-Total) scores. In the current study, we evaluated parent (income, education, family functioning, employment) and child variables (intelligence quotient [IQ], aggression type, comorbid symptomatology) as predictors or moderators, using linear mixed models and the MacArthur guidelines. Higher scores on ADHD symptom severity and callous/unemotional traits predicted better outcome on D-Total regardless of treatment assignment. Two moderators of D-Total were found: Higher anger/irritability symptoms and lower mania scores were associated with faster response, although not better overall effect at endpoint, in the augmented but not the basic group. Several variables moderated response on secondary outcomes (ADHD severity and prosocial behavior), and were characterized by faster response, although not better outcome, in the augmented but not in the basic group. Maternal education moderated outcome on the measure of positive social behavior; children of mothers with less education benefited more from augmented treatment relative to basic than those with more education. Although these findings require validation, they tentatively suggest that augmented treatment works equally well across the entire sample. Nevertheless, certain child characteristics may be useful indicators for the speed of response to augmented treatment.

Orion MPCV Continuum RCS Heating Augmentation Model Development

NASA Technical Reports Server (NTRS)

Hyatt, Andrew J.; White, Molly E.

2014-01-01

The reaction control system jets of the Orion Multi Purpose Crew Vehicle can have a significant impact on the magnitude and distribution of the surface heat flux on the leeside of the aft-body, when they are fired. Changes in surface heating are expressed in terms of augmentation factor over the baseline smooth body heating. Wind tunnel tests revealed heating augmentation factors as high as 13.0, 7.6, 2.8, and 5.8 for the roll, pitch down, pitch up, and yaw jets respectively. Heating augmentation factor models, based almost exclusively on data from a series of wind tunnel tests have been developed, for the purposes of thermal protection system design. The wind tunnel tests investigated several potential jet-to-freestream similarity parameters, and heating augmentation factors derived from the data showed correlation with the jet-to-freestream momentum ratio. However, this correlation was not utilized in the developed models. Instead augmentation factors were held constant throughout the potential trajectory space. This simplification was driven by the fact that ground to flight traceability and sting effects are not well understood. Given the sensitivity of the reaction control system jet heating augmentation to configuration, geometry, and orientation the focus in the present paper is on the methodology used to develop the models and the lessons learned from the data. The models that are outlined in the present work are specific to the aerothermal database used to design the thermal protection system for the Exploration Flight Test 1 vehicle.

Recycled water for stream flow augmentation: benefits, challenges, and the presence of wastewater-derived organic compounds.

PubMed

Plumlee, Megan H; Gurr, Christopher J; Reinhard, Martin

2012-11-01

Stream flow augmentation with recycled water has the potential to improve stream habitat and increase potable water supply, but the practice is not yet well understood or documented. The objectives of this report are to present a short review illustrated by a case study, followed by recommendations for future stream flow augmentation projects. Despite the fact that wastewater discharge to streams is commonplace, a water agency pursuing stream flow augmentation with recycled water will face unique challenges. For example, recycled water typically contains trace amounts of organic wastewater-derived compounds (OWCs) for which the potential ecological risks must be balanced against the benefits of an augmentation project. Successful stream flow augmentation with recycled water requires that the lead agency clearly articulate a strong project rationale and identify key benefits. It must be assumed that the public will have some concerns about water quality. Public acceptance may be better if an augmentation project has co-benefits beyond maintaining stream ecosystems, such as improving water system supply and reliability (i.e. potable use offset). Regulatory or project-specific criteria (acceptable concentrations of priority OWCs) would enable assessment of ecosystem impacts and demonstration of practitioner compliance. Additional treatment (natural or engineered) of the recycled water may be considered. If it is not deemed necessary or feasible, existing recycled water quality may be adequate to achieve project goals depending on project rationale, site and water quality evaluation, and public acceptance.

Patients and animal models of CNGβ1-deficient retinitis pigmentosa support gene augmentation approach

PubMed Central

Petersen-Jones, Simon M.; Occelli, Laurence M.; Winkler, Paige A.; Lee, Winston; Sparrow, Janet R.; Tsukikawa, Mai; Boye, Sanford L.; Chiodo, Vince; Capasso, Jenina E.; Becirovic, Elvir; Schön, Christian; Seeliger, Mathias W.; Levin, Alex V.; Hauswirth, William W.

2017-01-01

Retinitis pigmentosa (RP) is a major cause of blindness that affects 1.5 million people worldwide. Mutations in cyclic nucleotide-gated channel β 1 (CNGB1) cause approximately 4% of autosomal recessive RP. Gene augmentation therapy shows promise for treating inherited retinal degenerations; however, relevant animal models and biomarkers of progression in patients with RP are needed to assess therapeutic outcomes. Here, we evaluated RP patients with CNGB1 mutations for potential biomarkers of progression and compared human phenotypes with those of mouse and dog models of the disease. Additionally, we used gene augmentation therapy in a CNGβ1-deficient dog model to evaluate potential translation to patients. CNGB1-deficient RP patients and mouse and dog models had a similar phenotype characterized by early loss of rod function and slow rod photoreceptor loss with a secondary decline in cone function. Advanced imaging showed promise for evaluating RP progression in human patients, and gene augmentation using adeno-associated virus vectors robustly sustained the rescue of rod function and preserved retinal structure in the dog model. Together, our results reveal an early loss of rod function in CNGB1-deficient patients and a wide window for therapeutic intervention. Moreover, the identification of potential biomarkers of outcome measures, availability of relevant animal models, and robust functional rescue from gene augmentation therapy support future work to move CNGB1-RP therapies toward clinical trials. PMID:29202463

Reticular influences on primary and augmenting responses in the somatosensory cortex.

PubMed

Steriade, M; Morin, D

1981-01-26

The effects of brief, conditioning trains of high-frequency pulses to the midbrain reticular formation (RF) on primary and augmenting responses of somatosensory (SI) cortex were investigated. Testing stimulation was applied to the ventrobasal (VB) thalamus or to the white matter (WM) beneath SI in VB-lesioned animals. The RF-elicited EEG activation was associated with increased firing rates of SI neurons, enhanced probability of early synaptic discharges to VB or WM stimuli, and significantly reduced duration of the suppressed firing period following an afferent VB or WM volley. The diminished latency of the postinhibitory rebound under RF stimulation had the consequence that, within 10/sec shock-train, the second stimulus was delivered following completion of the rebound component and, instead of an augmented potential, generated a field response of primary-type. The dependence of the RF-induced change in augmenting potentials upon the sharpening effect exerted on the preceding inhibitory-rebound sequence was corroborated by analyzing the RF influence on neurons with different time-course of recovery from inhibition. The replacement of augmenting potentials by primary responses under RF stimulation is advanced as the mechanism behind the obliteration of spontaneously developing 'type I' spindle-waves during EEG arousal. The demonstration of RF influences on SI responses to WM stimulation in VB-lesioned animals points out the cortical level of the effects. The reticulo-thalamo-cortical pathways underlying these influences are discussed.

Nonexpansiveness of a linearized augmented Lagrangian operator for hierarchical convex optimization

NASA Astrophysics Data System (ADS)

Yamagishi, Masao; Yamada, Isao

2017-04-01

Hierarchical convex optimization concerns two-stage optimization problems: the first stage problem is a convex optimization; the second stage problem is the minimization of a convex function over the solution set of the first stage problem. For the hierarchical convex optimization, the hybrid steepest descent method (HSDM) can be applied, where the solution set of the first stage problem must be expressed as the fixed point set of a certain nonexpansive operator. In this paper, we propose a nonexpansive operator that yields a computationally efficient update when it is plugged into the HSDM. The proposed operator is inspired by the update of the linearized augmented Lagrangian method. It is applicable to characterize the solution set of recent sophisticated convex optimization problems found in the context of inverse problems, where the sum of multiple proximable convex functions involving linear operators must be minimized to incorporate preferable properties into the minimizers. For such a problem formulation, there has not yet been reported any nonexpansive operator that yields an update free from the inversions of linear operators in cases where it is utilized in the HSDM. Unlike previously known nonexpansive operators, the proposed operator yields an inversion-free update in such cases. As an application of the proposed operator plugged into the HSDM, we also present, in the context of the so-called superiorization, an algorithmic solution to a convex optimization problem over the generalized convex feasible set where the intersection of the hard constraints is not necessarily simple.

ACOG Committee Opinion no. 597: Committee on Obstetric Practice: Labor induction or augmentation and autism.

PubMed

2014-05-01

Functional oxytocin deficiency and a faulty oxytocin signaling pathway have been observed in conjunction with autism spectrum disorder (ASD). Because exogenous synthetic oxytocin commonly is administered for labor induction and augmentation, some have hypothesized that synthetic oxytocin used for these purposes may alter fetal oxytocin receptors and predispose exposed offspring to ASD. However, current evidence does not identify a causal relationship between labor induction or augmentation in general, or oxytocin labor induction specifically, and autism or ASD. Recognizing the limitations of available study design, conflicting data, and the potential consequences of limiting labor induction and augmentation, the Committee on Obstetric Practice recommends against a change in current guidance regarding counseling and indications for and methods of labor induction and augmentation.

75 FR 2107 - Notice of Availability of the Draft Environmental Assessment (Draft EA) for the Urban Stream...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-14

... discloses any potential significant impacts to the quality of the human environment that may arise from the... augmentation. The Urban Stream Research Center will propagate and augment the population densities and increase...

GPS/GLONASS RAIM augmentation to WAAS for CAT 1 precision approach

DOT National Transportation Integrated Search

1997-06-30

This paper deals with the potential use of Receiver Autonomous Integrity Monitoring @AIM) to supplement the FAAs Wide Area Augmentation System (WAAS). Integrity refers to the capability of a navigation or landing system to provide a timely warning...

Augmentation of the hard palate thin masticatory mucosa in the potential connective tissue donor sites using two collagen materials-Clinical and histological comparison.

PubMed

Bednarz, Wojciech; Kobierzycki, Christopher; Dzięgiel, Piotr; Botzenhart, Ute; Gedrange, Tomasz; Ziętek, Marek

2016-11-01

Due to the similarity of keratinized gingival and palatal mucosa the latter can pose as a potential donor site for gingival recession coverage. However, its availability is restricted and a thin transplant bears the risk of being rejected. The aim of the present study was to compare the clinical and histological results of thin palatal mucosa augmentation, using lyophilized Biokol ® xenogenous collagen sponge and a suspension of xenogenous Gel 0 ® pure collagen with non-augmented tissue from the same patients. Ten patients simultaneously underwent bilateral augmentation procedures using Biokol ® and Gel 0 ® collagen material. The donor sites were augmented 8 weeks prior to the harvesting of the connective tissue graft (CTG) for the gingival recession coverage procedures. Prior to the implantation of the collagen material and during the course of harvesting the augmented CTG, tissue specimens were taken for histological examination. Prior to the commencement of the study and after it, the parameters of palatal gingival thickness at 4mm (PGT1), and at 8mm apical to the gingival margin (PGT2) around the teeth neighboring the operating fields were determined. In both groups the palatal mucosa had thickened significantly in both measuring sites. An intergroup comparison revealed greater thickening of the masticatory mucosa in the Biokol ® group at both measuring points. The histological image of the grafts, obtained from sites augmented using both test methods, revealed a typical pattern of mature fibrous connective tissue. No epithelial cells were found. Augmentation of thin masticatory mucosa using Biokol ® or Gel 0 ® collagen materials resulted in a significant thickening of the mucosa, which could be demonstrated to be greater in the first group. Copyright © 2016 Elsevier GmbH. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yeung, Yu-Hong; Pothen, Alex; Halappanavar, Mahantesh

We present an augmented matrix approach to update the solution to a linear system of equations when the coefficient matrix is modified by a few elements within a principal submatrix. This problem arises in the dynamic security analysis of a power grid, where operators need to performmore » $N-x$ contingency analysis, i.e., determine the state of the system when up to $x$ links from $N$ fail. Our algorithms augment the coefficient matrix to account for the changes in it, and then compute the solution to the augmented system without refactoring the modified matrix. We provide two algorithms, a direct method, and a hybrid direct-iterative method for solving the augmented system. We also exploit the sparsity of the matrices and vectors to accelerate the overall computation. Our algorithms are compared on three power grids with PARDISO, a parallel direct solver, and CHOLMOD, a direct solver with the ability to modify the Cholesky factors of the coefficient matrix. We show that our augmented algorithms outperform PARDISO (by two orders of magnitude), and CHOLMOD (by a factor of up to 5). Further, our algorithms scale better than CHOLMOD as the number of elements updated increases. The solutions are computed with high accuracy. Our algorithms are capable of computing $N-x$ contingency analysis on a $778K$ bus grid, updating a solution with $x=20$ elements in $$1.6 \\times 10^{-2}$$ seconds on an Intel Xeon processor.« less

Short- and medium-term plasticity associated with augmenting responses in cortical slabs and spindles in intact cortex of cats in vivo

PubMed Central

Timofeev, Igor; Grenier, François; Bazhenov, Maxim; Houweling, Arthur R; Sejnowski, Terrence J; Steriade, Mircea

2002-01-01

Plastic changes in the synaptic responsiveness of neocortical neurones, which occur after rhythmic stimuli within the frequency range of sleep spindles (10 Hz), were investigated in isolated neocortical slabs and intact cortex of anaesthetized cats by means of single, dual and triple simultaneous intracellular recordings in conjunction with recordings of local field potential responses. In isolated cortical slabs (10 mm long, 6 mm wide and 4–5 mm deep), augmenting responses to pulse-trains at 10 Hz (responses with growing amplitudes from the second stimulus in a train) were elicited only by relatively high-intensity stimuli. At low intensities, responses were decremental. The largest augmenting responses were evoked in neurones located close to the stimulation site. Quantitative analyses of the number of action potentials and the amplitude and area of depolarization during augmenting responses in a population of neurones recorded from slabs showed that the most dramatic increases in the number of spikes with successive stimuli, and the greatest increase in depolarization amplitude, were found in conventional fast-spiking (FS) neurones. The largest increase in the area of depolarization was found in regular-spiking (RS) neurones. Dual intracellular recordings from a pair of FS and RS neurones in the slab revealed more action potentials in the FS neurone during augmenting responses and a significant increase in the depolarization area of the RS neurone that was dependent on the firing of the FS neurone. Self-sustained seizures could occur in the slab after rhythmic stimuli at 10 Hz. In the intact cortex, repeated sequences of stimuli generating augmenting responses or spontaneous spindles could induce an increased synaptic responsiveness to single stimuli, which lasted for several minutes. A similar time course of increased responsiveness was obtained with induction of cellular plasticity. These data suggest that augmenting responses elicited by stimulation, as well as spontaneously occurring spindles, may induce short- and medium-term plasticity of neuronal responses. PMID:12122155

First principles study on structural, electronic and optical properties of Ga1-xBxP ternary alloys (x = 0, 0.25, 0.5, 0.75 and 1)

NASA Astrophysics Data System (ADS)

Hoat, D. M.; Rivas Silva, J. F.; Méndez Blas, A.

2018-07-01

The structural, electronic and optical properties of GaP, BP binary compounds and their ternary alloys Ga1-xBxP (x = 0.25, 0.5 and 0.75) have been studied by full-potential linearized augmented plane wave (FP-LAPW) method within the framework of density functional theory (DFT) as implemented in WIEN2k package. Local density approximation (LDA) and generalized gradient approximation (GGA) as proposed by Perdew-Burke-Ernzerhof (PBE), Wu-Cohen (WC) and PBE for solid (PBESol) were used for treatment of exchange-correlation effect in calculations. Additionally, the Tran-Blaha modified Becke-Johnson (mBJ) potential was also employed for electronic and optical calculations due to that it gives very accurate band gap of solids. As B concentration increases, the lattice constant reduces and the energy band gap firstly decreases for small composition x and then it shows increasing trend until pure BP. Our results show that the indirect-direct band gap transition can be reached from x = 0.33. The linear optical properties, such as reflectivity, absorption coefficient, refractive index and optical conductivity of binary compounds and ternary alloys were derived from their calculated complex dielectric function in wide energy range up to 30 eV, and the alloying effect on these properties was also analyzed in detail.

Ligament augmentation for prevention of proximal junctional kyphosis and proximal junctional failure in adult spinal deformity.

PubMed

Safaee, Michael M; Deviren, Vedat; Dalle Ore, Cecilia; Scheer, Justin K; Lau, Darryl; Osorio, Joseph A; Nicholls, Fred; Ames, Christopher P

2018-05-01

OBJECTIVE Proximal junctional kyphosis (PJK) is a well-recognized, yet incompletely defined, complication of adult spinal deformity surgery. There is no standardized definition for PJK, but most studies describe PJK as an increase in the proximal junctional angle (PJA) of greater than 10°-20°. Ligament augmentation is a novel strategy for PJK reduction that provides strength to the upper instrumented vertebra (UIV) and adjacent segments while also reducing junctional stress at those levels. METHODS In this study, ligament augmentation was used in a consecutive series of adult spinal deformity patients at a single institution. Patient demographics, including age; sex; indication for surgery; revision surgery; surgical approach; and use of 3-column osteotomies, vertebroplasty, or hook fixation at the UIV, were collected. The PJA was measured preoperatively and at last follow-up using 36-inch radiographs. Data on change in PJA and need for revision surgery were collected. Univariate and multivariate analyses were performed to identify factors associated with change in PJA and proximal junctional failure (PJF), defined as PJK requiring surgical correction. RESULTS A total of 200 consecutive patients were included: 100 patients before implementation of ligament augmentation and 100 patients after implementation of this technique. The mean age of the ligament augmentation cohort was 66 years, and 67% of patients were women. Over half of these cases (51%) were revision surgeries, with 38% involving a combined anterior or lateral and posterior approach. The mean change in PJA was 6° in the ligament augmentation group compared with 14° in the control group (p < 0.001). Eighty-four patients had a change in PJA of less than 10°. In a multivariate linear regression model, age (p = 0.016), use of hook fixation at the UIV (p = 0.045), and use of ligament augmentation (p < 0.001) were associated with a change in PJA. In a separate model, only ligament augmentation (OR 0.193, p = 0.012) showed a significant association with PJF. CONCLUSIONS Ligament augmentation represents a novel technique for the prevention of PJK and PJF. Compared with a well-matched historical cohort, ligament augmentation is associated with a significant decrease in PJK and PJF. These data support the implementation of ligament augmentation in surgery for adult spinal deformity, particularly in patients with a high risk of developing PJK and PJF.

Impact of Posterior Wear on Muscle Length with Reverse Shoulder Arthroplasty.

PubMed

Roche, Christopher P; Diep, Phong; Hamilton, Matthew A; Wright, Thomas W; Flurin, Pierre-Henri; Zuckerman, Joseph D; Routman, Howard D

2015-12-01

The use of reverse total shoulder arthroplasty (rTSA) in patients with posterior glenoid wear can be challenging. Implanting a baseplate in the correct version may require significant eccentric reaming, which further medializes the joint line and results in greater rotator cuff muscle shortening. To restore the joint line, bone graft may be required, though it is associated with additional risks. As an alternative solution, augmented glenoid baseplates offer the potential to restore the joint line and improve rotator cuff muscle tensioning without the need for eccentric reaming or supplemental bone graft. To that end, this computer analysis quantifies the rotator cuff muscle length for standard and augmented rTSA when used in a normal and posteriorly worn glenoid. These results demonstrate that shortening of the rotator cuff occurred for both the standard and posterior augmented reverse shoulder designs with additional muscle shortening occurring in scapula with posteriorly worn glenoids. More anatomic rotator cuff muscle tensioning was observed with augmented glenoid baseplates. The use of posterior augmented glenoid baseplates has the potential to improve stability and better restore active internal and external rotation, a current limitation of rTSA. However, clinical follow-up is necessary to confirm these favorable biomechanical results.

An augmented reality haptic training simulator for spinal needle procedures.

PubMed

Sutherland, Colin; Hashtrudi-Zaad, Keyvan; Sellens, Rick; Abolmaesumi, Purang; Mousavi, Parvin

2013-11-01

This paper presents the prototype for an augmented reality haptic simulation system with potential for spinal needle insertion training. The proposed system is composed of a torso mannequin, a MicronTracker2 optical tracking system, a PHANToM haptic device, and a graphical user interface to provide visual feedback. The system allows users to perform simulated needle insertions on a physical mannequin overlaid with an augmented reality cutaway of patient anatomy. A tissue model based on a finite-element model provides force during the insertion. The system allows for training without the need for the presence of a trained clinician or access to live patients or cadavers. A pilot user study demonstrates the potential and functionality of the system.

Potential drawbacks in cell-assisted lipotransfer: A systematic review of existing reports (Review)

PubMed Central

HUANG, SHENG; ZHAO, WEILIANG; WANG, ZIHUA; TAO, KAI; LIU, XIAOYAN; CHANG, PENG

2016-01-01

Cell-assisted lipotransfer (CAL) has been widely used in various clinical applications, including breast augmentation following mammectomy, soft-tissue reconstruction and wound healing. However, the clinical application of CAL has been restricted due to the transplanted fat tissues being readily liquefied and absorbed. The present review examines 57 previously published studies involving CAL, including fat grafting or fat transfer with human adipose-stem cells in all known databases. Of these 57 articles, seven reported the clinical application of CAL. In the 57 studies, the majority of the fat tissues were obtained from the abdomen via liposuction of the seven clinical studies, four were performed in patients requiring breast augmentation, one in a patient requiring facial augmentation, one in a patient requiring soft tissue augmentation/reconstruction and one in a patient requiring fat in their upper arms. Despite the potential risks, there has been an increased demand for CAL in in cosmetic or aesthetic applications. Thus, criteria and guidelines are necessary for the clinical application of CAL technology. PMID:26677061

Systematic investigation of structural, electronic, optical and thermal properties of ternary MoAlB; an ab initio approach

NASA Astrophysics Data System (ADS)

Rajpoot, Priyanka; Rastogi, Anugya; Verma, U. P.

2018-02-01

Structural, electronic, optical and thermal properties of molybdenum aluminum boride (MoAlB) have been analyzed systematically using the full potential linearized augmented plane wave method based on density functional theory at ambient condition as well as high pressure and high temperature. Density of states and band structure calculation reflect the metallic character of MoAlB. In addition to this, the electron charge density calculation reveals the strong covalent bonding, in between ‘B’ atoms as well as ‘Mo’ and ‘B’ atoms. Optical parameters exhibit anisotropic nature and MoAlB become transparent in ultraviolet region for the radiation of energy above 25 eV. The thermal properties were investigated by using the quasi-harmonic Debye model at high temperature and high pressure.

Structural, electronic and magnetic properties of metal thiophosphate InPS4

NASA Astrophysics Data System (ADS)

Rajpoot, Priyanka; Nayak, Vikas; Kumari, Meena; Yadav, Priya; Nautiyal, Shashank; Verma, U. P.

2017-05-01

The non-centrosymmetric crystal, InPS4, has been investigated by means of density functional theory (DFT). In this paper we have calculated the structural parameters, electronic band structures, density of states plot and magnetic properties using full potential linearized augmented plane wave (FP-LAPW) method. The exchange correlation has been solved employing the generalised gradient approximation due to Perdew-Burke-Ernzerhof. The calculations are performed both without spin as well as spin polarized. The results show that InPS4 is an indirect band gap semiconductor with (N-Г) energy gap of 2.32eV (without spin) and 1.86eV in spin up and down channels.The obtained lattice parameters and energy gap agree well with the experimental results. Our reported magnetic moment results show that the property of InPS4is nonmagnetic.

Half-metallicity in the ferrimagnet [MnII(enH)(H2O)][CrIII(CN)6]·H2O: Ab initio study

NASA Astrophysics Data System (ADS)

Li, N.; Yao, K. L.; Zhong, G. H.; Ching, W. Y.

2013-03-01

The density-functional theory (DFT) within the full potential linearized augmented plane wave (FPLAPW) method is applied to study the two-dimensional achiral soft ferrimagnet [MnII(enH)(H2O)][CrIII(CN)6]·H2O. The phase stability, electronic structure, magnetic and conducting properties are investigated. Our results reveal that the compound has a stable ferrimagnetic ground state in good agreement with the experiment. From the spin density distribution, the spin magnetic moment of the compound is mainly from Cr3+ and Mn2+ ions with small contributions from the oxygen, nitrogen and carbon ions. The calculated electronic band structure predicts the compound to be a half-metal with the spin magnetic moment of 1.000 μB per molecule.

Shape Control of Plates with Piezo Actuators and Collocated Position/Rate Sensors

NASA Technical Reports Server (NTRS)

Balakrishnan, A. V.

1994-01-01

This paper treats the control problem of shaping the surface deformation of a circular plate using embedded piezo-electric actuators and collocated rate sensors. An explicit Linear Quadratic Gaussian (LQG) optimizer stability augmentation compensator is derived as well as the optimal feed-forward control. Corresponding performance evaluation formulas are also derived.

Shape Control of Plates with Piezo Actuators and Collocated Position/Rate Sensors

NASA Technical Reports Server (NTRS)

Balakrishnan, A. V.

1994-01-01

This paper treats the control problem of shaping the surface deformation of a circular plate using embedded piezo-electric actuator and collocated rate sensors. An explicit Linear Quadratic Gaussian (LQG) optimizer stability augmentation compensator is derived as well as the optimal feed-forward control. Corresponding performance evaluation formulas are also derived.

Sensitivity of control-augmented structure obtained by a system decomposition method

NASA Technical Reports Server (NTRS)

Sobieszczanskisobieski, Jaroslaw; Bloebaum, Christina L.; Hajela, Prabhat

1988-01-01

The verification of a method for computing sensitivity derivatives of a coupled system is presented. The method deals with a system whose analysis can be partitioned into subsets that correspond to disciplines and/or physical subsystems that exchange input-output data with each other. The method uses the partial sensitivity derivatives of the output with respect to input obtained for each subset separately to assemble a set of linear, simultaneous, algebraic equations that are solved for the derivatives of the coupled system response. This sensitivity analysis is verified using an example of a cantilever beam augmented with an active control system to limit the beam's dynamic displacements under an excitation force. The verification shows good agreement of the method with reference data obtained by a finite difference technique involving entire system analysis. The usefulness of a system sensitivity method in optimization applications by employing a piecewise-linear approach to the same numerical example is demonstrated. The method's principal merits are its intrinsically superior accuracy in comparison with the finite difference technique, and its compatibility with the traditional division of work in complex engineering tasks among specialty groups.

A Coupled Aeroelastic Model for Launch Vehicle Stability Analysis

NASA Technical Reports Server (NTRS)

Orr, Jeb S.

2010-01-01

A technique for incorporating distributed aerodynamic normal forces and aeroelastic coupling effects into a stability analysis model of a launch vehicle is presented. The formulation augments the linear state-space launch vehicle plant dynamics that are compactly derived as a system of coupled linear differential equations representing small angular and translational perturbations of the rigid body, nozzle, and sloshing propellant coupled with normal vibration of a set of orthogonal modes. The interaction of generalized forces due to aeroelastic coupling and thrust can be expressed as a set of augmenting non-diagonal stiffness and damping matrices in modal coordinates with no penalty on system order. While the eigenvalues of the structural response in the presence of thrust and aeroelastic forcing can be predicted at a given flight condition independent of the remaining degrees of freedom, the coupled model provides confidence in closed-loop stability in the presence of rigid-body, slosh, and actuator dynamics. Simulation results are presented that characterize the coupled dynamic response of the Ares I launch vehicle and the impact of aeroelasticity on control system stability margins.

Augmented Lagrange Hopfield network for solving economic dispatch problem in competitive environment

NASA Astrophysics Data System (ADS)

Vo, Dieu Ngoc; Ongsakul, Weerakorn; Nguyen, Khai Phuc

2012-11-01

This paper proposes an augmented Lagrange Hopfield network (ALHN) for solving economic dispatch (ED) problem in the competitive environment. The proposed ALHN is a continuous Hopfield network with its energy function based on augmented Lagrange function for efficiently dealing with constrained optimization problems. The ALHN method can overcome the drawbacks of the conventional Hopfield network such as local optimum, long computational time, and linear constraints. The proposed method is used for solving the ED problem with two revenue models of revenue based on payment for power delivered and payment for reserve allocated. The proposed ALHN has been tested on two systems of 3 units and 10 units for the two considered revenue models. The obtained results from the proposed methods are compared to those from differential evolution (DE) and particle swarm optimization (PSO) methods. The result comparison has indicated that the proposed method is very efficient for solving the problem. Therefore, the proposed ALHN could be a favorable tool for ED problem in the competitive environment.

Robust preview control for a class of uncertain discrete-time systems with time-varying delay.

PubMed

Li, Li; Liao, Fucheng

2018-02-01

This paper proposes a concept of robust preview tracking control for uncertain discrete-time systems with time-varying delay. Firstly, a model transformation is employed for an uncertain discrete system with time-varying delay. Then, the auxiliary variables related to the system state and input are introduced to derive an augmented error system that includes future information on the reference signal. This leads to the tracking problem being transformed into a regulator problem. Finally, for the augmented error system, a sufficient condition of asymptotic stability is derived and the preview controller design method is proposed based on the scaled small gain theorem and linear matrix inequality (LMI) technique. The method proposed in this paper not only solves the difficulty problem of applying the difference operator to the time-varying matrices but also simplifies the structure of the augmented error system. The numerical simulation example also illustrates the effectiveness of the results presented in the paper. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Micro-CT image reconstruction based on alternating direction augmented Lagrangian method and total variation.

PubMed

Gopi, Varun P; Palanisamy, P; Wahid, Khan A; Babyn, Paul; Cooper, David

2013-01-01

Micro-computed tomography (micro-CT) plays an important role in pre-clinical imaging. The radiation from micro-CT can result in excess radiation exposure to the specimen under test, hence the reduction of radiation from micro-CT is essential. The proposed research focused on analyzing and testing an alternating direction augmented Lagrangian (ADAL) algorithm to recover images from random projections using total variation (TV) regularization. The use of TV regularization in compressed sensing problems makes the recovered image quality sharper by preserving the edges or boundaries more accurately. In this work TV regularization problem is addressed by ADAL which is a variant of the classic augmented Lagrangian method for structured optimization. The per-iteration computational complexity of the algorithm is two fast Fourier transforms, two matrix vector multiplications and a linear time shrinkage operation. Comparison of experimental results indicate that the proposed algorithm is stable, efficient and competitive with the existing algorithms for solving TV regularization problems. Copyright © 2013 Elsevier Ltd. All rights reserved.

Using Augmented Reality to Teach and Learn Biochemistry

ERIC Educational Resources Information Center

Vega Garzón, Juan Carlos; Magrini, Marcio Luiz; Galembeck, Eduardo

2017-01-01

Understanding metabolism and metabolic pathways constitutes one of the central aims for students of biological sciences. Learning metabolic pathways should be focused on the understanding of general concepts and core principles. New technologies such Augmented Reality (AR) have shown potential to improve assimilation of biochemistry abstract…

Semiochemical lures reduce emigration and enhance pest control services in open-field predator augmentation

USDA-ARS?s Scientific Manuscript database

Augmentation biocontrol is a commercially viable pest management tactic in enclosed glasshouse environments, but is far less effective in open-field agriculture where newly released enemies rapidly disperse from release sites. We tested the potential for behavior-modifying semiochemicals to increase...

Visual Evoked Potential Augmenting-Reducing and Personality: The Vertex Augmenter is a Sensation Seeker

DTIC Science & Technology

1987-01-01

disinhibition (DIS) measures a hedonistic , extraverted lifestyle including drinking, parties, sex and gambling; boredom susceptibility (BS) indicates an...has reported that the correlation with A/R is often the strongest with the disinhibition scale, which measures a hedonistic pursuit of extraverted

Stability Assessment and Tuning of an Adaptively Augmented Classical Controller for Launch Vehicle Flight Control

NASA Technical Reports Server (NTRS)

VanZwieten, Tannen; Zhu, J. Jim; Adami, Tony; Berry, Kyle; Grammar, Alex; Orr, Jeb S.; Best, Eric A.

2014-01-01

Recently, a robust and practical adaptive control scheme for launch vehicles [ [1] has been introduced. It augments a classical controller with a real-time loop-gain adaptation, and it is therefore called Adaptive Augmentation Control (AAC). The loop-gain will be increased from the nominal design when the tracking error between the (filtered) output and the (filtered) command trajectory is large; whereas it will be decreased when excitation of flex or sloshing modes are detected. There is a need to determine the range and rate of the loop-gain adaptation in order to retain (exponential) stability, which is critical in vehicle operation, and to develop some theoretically based heuristic tuning methods for the adaptive law gain parameters. The classical launch vehicle flight controller design technics are based on gain-scheduling, whereby the launch vehicle dynamics model is linearized at selected operating points along the nominal tracking command trajectory, and Linear Time-Invariant (LTI) controller design techniques are employed to ensure asymptotic stability of the tracking error dynamics, typically by meeting some prescribed Gain Margin (GM) and Phase Margin (PM) specifications. The controller gains at the design points are then scheduled, tuned and sometimes interpolated to achieve good performance and stability robustness under external disturbances (e.g. winds) and structural perturbations (e.g. vehicle modeling errors). While the GM does give a bound for loop-gain variation without losing stability, it is for constant dispersions of the loop-gain because the GM is based on frequency-domain analysis, which is applicable only for LTI systems. The real-time adaptive loop-gain variation of the AAC effectively renders the closed-loop system a time-varying system, for which it is well-known that the LTI system stability criterion is neither necessary nor sufficient when applying to a Linear Time-Varying (LTV) system in a frozen-time fashion. Therefore, a generalized stability metric for time-varying loop=gain perturbations is needed for the AAC.

Effects of Creatine Monohydrate Augmentation on Brain Metabolic and Network Outcome Measures in Women With Major Depressive Disorder.

PubMed

Yoon, Sujung; Kim, Jieun E; Hwang, Jaeuk; Kim, Tae-Suk; Kang, Hee Jin; Namgung, Eun; Ban, Soonhyun; Oh, Subin; Yang, Jeongwon; Renshaw, Perry F; Lyoo, In Kyoon

2016-09-15

Creatine monohydrate (creatine) augmentation has the potential to accelerate the clinical responses to and enhance the overall efficacy of selective serotonin reuptake inhibitor treatment in women with major depressive disorder (MDD). Although it has been suggested that creatine augmentation may involve the restoration of brain energy metabolism, the mechanisms underlying its antidepressant efficacy are unknown. In a randomized, double-blind, placebo-controlled trial, 52 women with MDD were assigned to receive either creatine augmentation or placebo augmentation of escitalopram; 34 subjects participated in multimodal neuroimaging assessments at baseline and week 8. Age-matched healthy women (n = 39) were also assessed twice at the same intervals. Metabolic and network outcomes were measured for changes in prefrontal N-acetylaspartate and changes in rich club hub connections of the structural brain network using proton magnetic resonance spectroscopy and diffusion tensor imaging, respectively. We found MDD-related metabolic and network dysfunction at baseline. Improvement in depressive symptoms was greater in patients receiving creatine augmentation relative to placebo augmentation. After 8 weeks of treatment, prefrontal N-acetylaspartate levels increased significantly in the creatine augmentation group compared with the placebo augmentation group. Increment in rich club hub connections was also greater in the creatine augmentation group than in the placebo augmentation group. N-acetylaspartate levels and rich club connections increased after creatine augmentation of selective serotonin reuptake inhibitor treatment. Effects of creatine administration on brain energy metabolism and network organization may partly underlie its efficacy in treating women with MDD. Copyright © 2016 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Surface calculations with asymptotically long-ranged potentials in the full-potential linearized augmented plane-wave method

NASA Astrophysics Data System (ADS)

Ye, Lin-Hui

2015-09-01

Although the supercell method has been widely used for surface calculations, it only works well with short-ranged potentials, but meets difficulty when the potential decays very slowly into the vacuum. Unfortunately, the exact exchange-correlation potential of the density functional theory is asymptotically long ranged, and therefore is not easily handled by use of supercells. This paper illustrates that the authentic slab geometry, another technique for surface calculations, is not affected by this issue: It works equally well with both short- and long-ranged potentials, with the computational cost and the convergence speed being essentially the same. Using the asymptotically long-ranged Becke-Roussel'89 exchange potential as an example, we have calculated six surfaces of various types. We found that accurate potential values can be obtained even in extremely low density regions of more than 100 Å away from the surface. This high performance allows us to explore the asymptotic region, and prove with clean numerical evidence that the Becke-Roussel'89 potential satisfies the correct asymptotic behavior for slab surfaces, as it does for finite systems. Our finding further implies that the Slater component of the exact exchange optimized effective potential is responsible for the asymptotic behavior, not only for jellium slabs, but for slabs of any type. The Becke-Roussel'89 potential may therefore be used to build asymptotically correct model exchange potentials applicable to both finite systems and slab surfaces.

Leveraging Mobile Games for Place-Based Language Learning

ERIC Educational Resources Information Center

Holden, Christopher L.; Sykes, Julie M.

2011-01-01

This paper builds on the emerging body of research aimed at exploring the educational potential of mobile technologies, specifically, how to leverage place-based, augmented reality mobile games for language learning. Mentira is the first place-based, augmented reality mobile game for learning Spanish in a local neighborhood in the Southwestern…

Effect of Hydrostatic Pressure on the Structural, Electronic and Optical Properties of SnS2 with a Cubic Structure: The DFT Approach

NASA Astrophysics Data System (ADS)

Bakhshayeshi, A.; Taghavi Mendi, R.; Majidiyan Sarmazdeh, M.

2018-02-01

Recently, a cubic structure of polymorphic SnS2 has been synthesized experimentally, which is stable at room temperature. In this paper, we calculated some structural, electronic and optical properties of the cubic SnS2 structure based on the full potential-linearized augmented plane waves method. We also studied the effect of hydrostatic pressure on the physical properties of the cubic SnS2 structure. Structural results show that the compressibility of the cubic SnS2 phase is greater than its trigonal phase and the compressibility decreases with increasing pressure. Investigations of the electronic properties indicate that pressure changes the density of states and the energy band gap increases with increasing pressure. The variation of energy band gap versus pressure is almost linear. We concluded that cubic SnS2 is a semiconductor with an indirect energy band gap, like its trigonal phase. The optical calculations revealed that the dielectric constant decreases with increasing pressure, and the width of the forbidden energy interval increases for electromagnetic wave propagation. Moreover, plasmonic energy and refractive index are changed with increasing pressure.

Oxytocin regimen for labor augmentation, labor progression, and perinatal outcomes.

PubMed

Zhang, Jun; Branch, D Ware; Ramirez, Mildred M; Laughon, S Katherine; Reddy, Uma; Hoffman, Mathew; Bailit, Jennifer; Kominiarek, Michelle; Chen, Zhen; Hibbard, Judith U

2011-08-01

To examine the effects and safety of high-dose (compared with low-dose) oxytocin regimen for labor augmentation on perinatal outcomes. Data from the Consortium on Safe Labor were used. A total of 15,054 women from six hospitals were eligible for the analysis. Women were grouped based on their oxytocin starting dose and incremental dosing of 1, 2, and 4 milliunits/min. Duration of labor and a number of maternal and neonatal outcomes were compared among these three groups stratified by parity. Multivariable logistic regression and generalized linear mixed model were used to adjust for potential confounders. Oxytocin regimen did not affect the rate of cesarean delivery or other perinatal outcomes. Compared with 1 milliunit/min, the regimens starting with 2 milliunits/min and 4 milliunits/min reduced the duration of first stage by 0.8 hours (95% confidence interval 0.5-1.1) and 1.3 hours (1.0-1.7), respectively, in nulliparous women. No effect was observed on the second stage of labor. Similar patterns were observed in multiparous women. High-dose regimen was associated with a reduced risk of meconium stain, chorioamnionitis, and newborn fever in multiparous women. High-dose oxytocin regimen (starting dose at 4 milliunits/min and increment of 4 millliunits/min) is associated with a shorter duration of first-stage of labor for all parities without increasing the cesarean delivery rate or adversely affecting perinatal outcomes. II.

Neuroticism Magnifies the Detrimental Association between Social Media Addiction Symptoms and Wellbeing in Women, but Not in Men: a three-Way Moderation Model.

PubMed

Turel, Ofir; Poppa, Natalie Tasha; Gil-Or, Oren

2018-02-03

Addiction symptoms in relation to the use of social networking sites (SNS) can be associated with reduced wellbeing. However, the mechanisms that can control this association have not been fully characterized, despite their relevance to effective treatment of individuals presenting SNS addiction symptoms. In this study we hypothesize that sex and neuroticism, which are important determinants of how people evaluate and respond to addiction symptoms, moderate this association. To examine these assertions, we employed hierarchical linear and logistic regression techniques to analyze data collected with a cross-sectional survey of 215 Israeli college students who use SNS. Results lend support to the hypothesized negative association between SNS addiction symptoms and wellbeing (as well as potentially being at-risk for low mood/ mild depression), and the ideas that (1) this association is augmented by neuroticism, and (2) that the augmentation is stronger for women than for men. They demonstrated that the sexes may differ in their SNS addiction-wellbeing associations: while men had similar addiction symptoms -wellbeing associations across neuroticism levels, women with high levels of neuroticism presented much steeper associations compared to women with low neuroticism. This provides an interesting account of possible "telescoping effect", the idea that addicted women present a more severe clinical profile compared to men, in the case of technology-"addictions".

Stress formulation in the all-electron full-potential linearized augmented plane wave method

NASA Astrophysics Data System (ADS)

Nagasako, Naoyuki; Oguchi, Tamio

2012-02-01

Stress formulation in the linearlized augmented plane wave (LAPW) method has been proposed in 2002 [1] as an extension of the force formulation in the LAPW method [2]. However, pressure calculations only for Al and Si were reported in Ref.[1] and even now stress calculations have not yet been fully established in the LAPW method. In order to make it possible to efficiently relax lattice shape and atomic positions simultaneously and to precisely evaluate the elastic constants in the LAPW method, we reformulate stress formula in the LAPW method with the Soler-Williams representation [3]. Validity of the formulation is tested by comparing the pressure obtained as the trace of stress tensor with that estimated from total energies for a wide variety of material systems. Results show that pressure is estimated within the accuracy of less than 0.1 GPa. Calculations of the shear elastic constant show that the shear components of the stress tensor are also precisely computed with the present formulation [4].[4pt] [1] T. Thonhauser et al., Solid State Commun. 124, 275 (2002).[0pt] [2] R. Yu et al., Phys. Rev. B 43, 6411 (1991).[0pt] [3] J. M. Soler and A. R. Williams, Phys. Rev. B 40, 1560 (1989).[0pt] [4] N. Nagasako and T. Oguchi, J. Phys. Soc. Jpn. 80, 024701 (2011).

Thinking Cap Plus Thinking Zap: tDCS of Frontopolar Cortex Improves Creative Analogical Reasoning and Facilitates Conscious Augmentation of State Creativity in Verb Generation.

PubMed

Green, Adam E; Spiegel, Katherine A; Giangrande, Evan J; Weinberger, Adam B; Gallagher, Natalie M; Turkeltaub, Peter E

2017-04-01

Recent neuroimaging evidence indicates neural mechanisms that support transient improvements in creative performance (augmented state creativity) in response to cognitive interventions (creativity cueing). Separately, neural interventions via tDCS show encouraging potential for modulating neuronal function during creative performance. If cognitive and neural interventions are separately effective, can they be combined? Does state creativity augmentation represent "real" creativity, or do interventions simply yield divergence by diminishing meaningfulness/appropriateness? Can augmenting state creativity bolster creative reasoning that supports innovation, particularly analogical reasoning? To address these questions, we combined tDCS with creativity cueing. Testing a regionally specific hypothesis from neuroimaging, high-definition tDCS-targeted frontopolar cortex activity recently shown to predict state creativity augmentation. In a novel analogy finding task, participants under tDCS formulated substantially more creative analogical connections in a large matrix search space (creativity indexed via latent semantic analysis). Critically, increased analogical creativity was not due to diminished accuracy in discerning valid analogies, indicating "real" creativity rather than inappropriate divergence. A simpler relational creativity paradigm (modified verb generation) revealed a tDCS-by-cue interaction; tDCS further enhanced creativity cue-related increases in semantic distance. Findings point to the potential of noninvasive neuromodulation to enhance creative relational cognition, including augmentation of the deliberate effort to formulate connections between distant concepts. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Research on gesture recognition of augmented reality maintenance guiding system based on improved SVM

NASA Astrophysics Data System (ADS)

Zhao, Shouwei; Zhang, Yong; Zhou, Bin; Ma, Dongxi

2014-09-01

Interaction is one of the key techniques of augmented reality (AR) maintenance guiding system. Because of the complexity of the maintenance guiding system's image background and the high dimensionality of gesture characteristics, the whole process of gesture recognition can be divided into three stages which are gesture segmentation, gesture characteristic feature modeling and trick recognition. In segmentation stage, for solving the misrecognition of skin-like region, a segmentation algorithm combing background mode and skin color to preclude some skin-like regions is adopted. In gesture characteristic feature modeling of image attributes stage, plenty of characteristic features are analyzed and acquired, such as structure characteristics, Hu invariant moments features and Fourier descriptor. In trick recognition stage, a classifier based on Support Vector Machine (SVM) is introduced into the augmented reality maintenance guiding process. SVM is a novel learning method based on statistical learning theory, processing academic foundation and excellent learning ability, having a lot of issues in machine learning area and special advantages in dealing with small samples, non-linear pattern recognition at high dimension. The gesture recognition of augmented reality maintenance guiding system is realized by SVM after the granulation of all the characteristic features. The experimental results of the simulation of number gesture recognition and its application in augmented reality maintenance guiding system show that the real-time performance and robustness of gesture recognition of AR maintenance guiding system can be greatly enhanced by improved SVM.

Treatment of Linear Scleroderma (en Coup de Sabre) With Dermal Fat Grafting.

PubMed

Barin, Ensar Zafer; Cinal, Hakan; Cakmak, Mehmet Akif; Tan, Onder

2016-05-01

Linear scleroderma, also known as "en coup de sabre," is a subtype of localized scleroderma that warrants aesthetic correction because it appears on the forehead region in children. To report dermal fat grafting as a novel and effective surgical treatment option in linear scleroderma. Under local anesthesia, a dermal fat graft was successfully placed into a subcutaneous pocket that was prepared underneath the depressed scar. The donor site was closed primarily. No early or late complications developed postoperatively. After 1-year follow-up, the dermal fat graft was viable, the depressed scar was adequately augmented, and a good aesthetic result and patient satisfaction were obtained. We believe that dermal fat grafting is a cost-effective option and provides a long-lasting aesthetic outcome in the management of linear scleroderma. © The Author(s) 2015.

Elastic robot control - Nonlinear inversion and linear stabilization

NASA Technical Reports Server (NTRS)

Singh, S. N.; Schy, A. A.

1986-01-01

An approach to the control of elastic robot systems for space applications using inversion, servocompensation, and feedback stabilization is presented. For simplicity, a robot arm (PUMA type) with three rotational joints is considered. The third link is assumed to be elastic. Using an inversion algorithm, a nonlinear decoupling control law u(d) is derived such that in the closed-loop system independent control of joint angles by the three joint torquers is accomplished. For the stabilization of elastic oscillations, a linear feedback torquer control law u(s) is obtained applying linear quadratic optimization to the linearized arm model augmented with a servocompensator about the terminal state. Simulation results show that in spite of uncertainties in the payload and vehicle angular velocity, good joint angle control and damping of elastic oscillations are obtained with the torquer control law u = u(d) + u(s).

Transduction between worlds: using virtual and mixed reality for earth and planetary science

NASA Astrophysics Data System (ADS)

Hedley, N.; Lochhead, I.; Aagesen, S.; Lonergan, C. D.; Benoy, N.

2017-12-01

Virtual reality (VR) and augmented reality (AR) have the potential to transform the way we visualize multidimensional geospatial datasets in support of geoscience research, exploration and analysis. The beauty of virtual environments is that they can be built at any scale, users can view them at many levels of abstraction, move through them in unconventional ways, and experience spatial phenomena as if they had superpowers. Similarly, augmented reality allows you to bring the power of virtual 3D data visualizations into everyday spaces. Spliced together, these interface technologies hold incredible potential to support 21st-century geoscience. In my ongoing research, my team and I have made significant advances to connect data and virtual simulations with real geographic spaces, using virtual environments, geospatial augmented reality and mixed reality. These research efforts have yielded new capabilities to connect users with spatial data and phenomena. These innovations include: geospatial x-ray vision; flexible mixed reality; augmented 3D GIS; situated augmented reality 3D simulations of tsunamis and other phenomena interacting with real geomorphology; augmented visual analytics; and immersive GIS. These new modalities redefine the ways in which we can connect digital spaces of spatial analysis, simulation and geovisualization, with geographic spaces of data collection, fieldwork, interpretation and communication. In a way, we are talking about transduction between real and virtual worlds. Taking a mixed reality approach to this, we can link real and virtual worlds. This paper presents a selection of our 3D geovisual interface projects in terrestrial, coastal, underwater and other environments. Using rigorous applied geoscience data, analyses and simulations, our research aims to transform the novelty of virtual and augmented reality interface technologies into game-changing mixed reality geoscience.

Osteogenic potential of mesenchymal cells embedded in the provisional matrix after a 6-week healing period in augmented and non-augmented extraction sockets: an immunohistochemical prospective pilot study in humans.

PubMed

Heberer, Susanne; Wustlich, Alexander; Lage, Hermann; Nelson, John J; Nelson, Katja

2012-01-01

The aim of the present clinical study was the evaluation of the osteogenic potential of mesenchymal cells embedded in the provisional matrix of non-augmented and with Bio-Oss collagen-augmented human extraction sockets after 6 weeks of healing time. Twenty-five patients with 47 extraction sites participated in the present study. After tooth removal, the extraction sockets were augmented with Bio-Oss collagen or not augmented. At implant placement, bone biopsies of the extraction sockets were obtained. The immunohistochemical analysis of the osteogenic potential of the mesenchymal cells in the provisional matrix was performed using three monoclonal antibodies: core-binding factor α1 (Cbfa1)/runt-related protein (Runx)2, osteonectin (OSN/secreted protein acidic and rich in cyst [SPARC]) and osteocalcin (OC). The statistical analysis was performed using two-factorial analysis for repeated measures, Mann-Whitney U-test and Spearman's rank-order correlation coefficient. Of 47 extraction sockets examined, 17 sockets demonstrated an almost complete ossification. Hence, the provisional matrix of the 30 remaining extraction sockets (21 non-augmented, 9 augmented) was immunohistochemically investigated. No evidence of acute or chronic inflammation was noted in any of the specimens. In the provisional matrix of the non-grafted socket, the median amount of Cbfa1/Runx2-positive cells was 72.3%, of OSN (SPARC) 66.9% and of OC 23.4%, whereas in the grafted sockets the median rate of immunopositive cells staining with Cbfa1/Runx2 was 73.3%, of OSN (SPARC) 61.4% and of OC 20.1%. There was no significant difference in the proportion of positive cells expressed by Cbfa1/Runx2, OSN/SPARC and OC between the grafted and non-grafted socket. Furthermore, the cell density did not correlate to the quantity of stained cells independent of the used proteins. After a 6-week healing period, the provisional matrix was demonstrated to have a high proportion of cells displaying a maturation of mature osteoprogenitor cells to osteoblasts. The grafting procedure did not influence the quantity of osteogenic cells in the extraction socket. © 2011 John Wiley & Sons A/S.

Ab-initio study of thermodynamic stability, thermoelectric and optical properties of perovskites ATiO3 (A=Pb, Sn)

NASA Astrophysics Data System (ADS)

Noor, N. A.; Mahmood, Q.; Rashid, Muhammad; Ul Haq, Bakhtiar; Laref, A.; Ahmad, S. A.

2018-07-01

The physical behavior of perovskites ATiO3 (A=Pb, Sn) has been explored by using density functional theory based full-potential linearized-augmented-plane-wave plus local-orbital (FP-LAPW+lo) method. The lattice parameters calculated from the optimized structures by using Murnaghan equation of state and Chapin's method have been found in good agreement with the available literature that ensures the reliability of the adopted methodology. Moreover, the optoelectronic and thermoelectric properties have been elaborated by using modified Becke-Johnson exchange potential. The optical behavior has been explored in terms the dielectric constants, refractive indices, absorption spectra and optical loss factors. The absorption spectra of these materials reveal a large absorption in the visible and low ultraviolet part of incident light. The thermoelectric properties of ATiO3 are explained in terms of electrical conductivities, thermal conductivities, power factors, and the specific heat capacities. The ATiO3family of pervoskites has been found to exhibit the bandgaps falling in the visible region of solar spectrum and show high values of thermal efficiency that make them potential multifunctional candidates for optoelectronic and energy harvesting applications.

Electronic, Optical and Thermoelectric Properties of 2H-CuAlO2: A First Principles Study

NASA Astrophysics Data System (ADS)

Bhamu, K. C.; Khenata, R.; Khan, Saleem Ayaz; Singh, Mangej; Priolkar, K. R.

2016-01-01

The electronic and optical properties of 2H-CuAlO2, including energy bands, density of states (DOS), optical dielectric behaviour, refractive index, absorption coefficient and optical conductivity, have been investigated within the framework of a full-potential linearized augmented plane wave scheme using different potentials. The direct and indirect band gaps for CuAlO2, computed using the Becke-Johnson potential, are estimated at 3.53 eV and 2.48 eV, respectively, which are in better agreement with the experimentally reported band gaps than those previously computed. The origin of energy bands is elucidated in terms of DOS, while the behaviour of the imaginary part of the dielectric constant is explained in terms of electronic transitions from valence bands to conduction bands. The computed value of the refractive index is 2.25 (1.94) for light perpendicular (parallel) to the c axis, in concordance with the available values. The overall shape of the spectral distribution for absorption coefficient and optical conductivity is also in accord with the reported data. The investigated thermoelectric properties indicate that CuAlO2 is a p-type semiconductor showing high effectiveness at low temperatures.

All-electron GW quasiparticle band structures of group 14 nitride compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chu, Iek-Heng; Cheng, Hai-Ping, E-mail: cheng@qtp.ufl.edu; Kozhevnikov, Anton

We have investigated the group 14 nitrides (M{sub 3}N{sub 4}) in the spinel phase (γ-M{sub 3}N{sub 4} with M = C, Si, Ge, and Sn) and β phase (β-M{sub 3}N{sub 4} with M = Si, Ge, and Sn) using density functional theory with the local density approximation and the GW approximation. The Kohn-Sham energies of these systems have been first calculated within the framework of full-potential linearized augmented plane waves (LAPW) and then corrected using single-shot G{sub 0}W{sub 0} calculations, which we have implemented in the modified version of the Elk full-potential LAPW code. Direct band gaps at the Γmore » point have been found for spinel-type nitrides γ-M{sub 3}N{sub 4} with M = Si, Ge, and Sn. The corresponding GW-corrected band gaps agree with experiment. We have also found that the GW calculations with and without the plasmon-pole approximation give very similar results, even when the system contains semi-core d electrons. These spinel-type nitrides are novel materials for potential optoelectronic applications because of their direct and tunable band gaps.« less

Effectiveness of basic display augmentation in vehicular control by visual field cues

NASA Technical Reports Server (NTRS)

Grunwald, A. J.; Merhav, S. J.

1978-01-01

The paper investigates the effectiveness of different basic display augmentation concepts - fixed reticle, velocity vector, and predicted future vehicle path - for RPVs controlled by a vehicle-mounted TV camera. The task is lateral manual control of a low flying RPV along a straight reference line in the presence of random side gusts. The man-machine system and the visual interface are modeled as a linear time-invariant system. Minimization of a quadratic performance criterion is assumed to underlie the control strategy of a well-trained human operator. The solution for the optimal feedback matrix enables the explicit computation of the variances of lateral deviation and directional error of the vehicle and of the control force that are used as performance measures.

Myelopotentiating effect of curcumin in tumor-bearing host: Role of bone marrow resident macrophages

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vishvakarma, Naveen Kumar; Kumar, Anjani; Kumar, Ajay

2012-08-15

The present investigation was undertaken to study if curcumin, which is recognized for its potential as an antineoplastic and immunopotentiating agent, can also influence the process of myelopoiesis in a tumor-bearing host. Administration of curcumin to tumor-bearing host augmented count of bone marrow cell (BMC) accompanied by an up-regulated BMC survival and a declined induction of apoptosis. Curcumin administration modulated expression of cell survival regulatory molecules: Bcl2, p53, caspase-activated DNase (CAD) and p53-upregulated modulator of apoptosis (PUMA) along with enhanced expression of genes of receptors for M-CSF and GM-CSF in BMC. The BMC harvested from curcumin-administered hosts showed an up-regulatedmore » colony forming ability with predominant differentiation into bone marrow-derived macrophages (BMDM), responsive for activation to tumoricidal state. The number of F4/80 positive bone marrow resident macrophages (BMM), showing an augmented expression of M-CSF, was also augmented in the bone marrow of curcumin-administered host. In vitro reconstitution experiments indicated that only BMM of curcumin-administered hosts, but not in vitro curcumin-exposed BMM, augmented BMC survival. It suggests that curcumin-dependent modulation of BMM is of indirect nature. Such prosurvival action of curcumin is associated with altered T{sub H1}/T{sub H2} cytokine balance in serum. Augmented level of serum-borne IFN-γ was found to mediate modulation of BMM to produce enhanced amount of monokines (IL-1, IL-6, TNF-α), which are suggested to augment the BMC survival. Taken together the present investigation indicates that curcumin can potentiate myelopoiesis in a tumor-bearing host, which may have implications in its therapeutic utility. Highlights: ► Curcumin augments myelopoiesis in tumor-bearing host. ► Bone marrow resident macrophages mediate curcumin-dependent augmented myelopoiesis. ► Serum borne cytokine are implicated in modulation of bone marrow resident macrophages.« less

Antidepressant response to aripiprazole augmentation associated with enhanced FDOPA utilization in striatum: a preliminary PET study

PubMed Central

Conway, Charles R.; Chibnall, John T.; Cumming, Paul; Mintun, Mark A.; Gebara, Marie Anne I.; Perantie, Dana C.; Price, Joseph L.; Cornell, Martha E.; McConathy, Jonathan E.; Gangwani, Sunil; Sheline, Yvette I.

2014-01-01

Several double blind, prospective trials have demonstrated an antidepressant augmentation efficacy of aripiprazole in depressed patients unresponsive to standard antidepressant therapy. Although aripiprazole is now widely used for this indication, and much is known about its receptor-binding properties, the mechanism of its antidepressant augmentation remains ill-defined. In vivo animal studies and in vitro human studies using cloned dopamine dopamine D2 receptors suggest aripiprazole is a partial dopamine agonist; in this preliminary neuroimaging trial, we hypothesized that aripiprazole’s antidepressant augmentation efficacy arises from dopamine partial agonist activity. To test this, we assessed the effects of aripiprazole augmentation on the cerebral utilization of 6-[18F]-fluoro-3,4-dihydroxy-L-phenylalanine (FDOPA) using positron emission tomography (PET). Fourteen depressed patients, who had failed 8 weeks of antidepressant therapy with selective serotonin reuptake inhibitors, underwent FDOPA PET scans before and after aripiprazole augmentation; eleven responded to augmentation. Whole brain, voxel-wise comparisons of pre- and post-aripiprazole scans revealed increased FDOPA trapping in the right medial caudate of augmentation responders. An exploratory analysis of depressive symptoms revealed that responders experienced large improvements only in putatively dopaminergic symptoms of lassitude and inability to feel. These preliminary findings suggest that augmentation of antidepressant response by aripiprazole may be associated with potentiation of dopaminergic activity. PMID:24468015

A Benzothiadiazole Primes Parsley Cells for Augmented Elicitation of Defense Responses

PubMed Central

Katz, Vera A.; Thulke, Oliver U.; Conrath, Uwe

1998-01-01

Systemic acquired resistance is an important component of the disease-resistance arsenal of plants, and is associated with an enhanced potency for activating local defense responses upon pathogen attack. Here we demonstrate that pretreatment with benzothiadiazole (BTH), a synthetic activator of acquired resistance in plants, augmented the sensitivity for low-dose elicitation of coumarin phytoalexin secretion by cultured parsley (Petroselinum crispum L.) cells. Enhanced coumarin secretion was associated with potentiated activation of genes encoding Phe ammonia-lyase (PAL). The augmentation of PAL gene induction was proportional to the length of pretreatment with BTH, indicating time-dependent priming of the cells. In contrast to the PAL genes, those for anionic peroxidase were directly induced by BTH in the absence of elicitor, thus confirming a dual role for BTH in the activation of plant defenses. Strikingly, the ability of various chemicals to enhance plant disease resistance correlated with their capability to potentiate parsley PAL gene elicitation, emphasizing an important role for defense response potentiation in acquired plant disease resistance. PMID:9701589

Symmetric linear systems - An application of algebraic systems theory

NASA Technical Reports Server (NTRS)

Hazewinkel, M.; Martin, C.

1983-01-01

Dynamical systems which contain several identical subsystems occur in a variety of applications ranging from command and control systems and discretization of partial differential equations, to the stability augmentation of pairs of helicopters lifting a large mass. Linear models for such systems display certain obvious symmetries. In this paper, we discuss how these symmetries can be incorporated into a mathematical model that utilizes the modern theory of algebraic systems. Such systems are inherently related to the representation theory of algebras over fields. We will show that any control scheme which respects the dynamical structure either implicitly or explicitly uses the underlying algebra.

Feel, Imagine and Learn!--Haptic Augmented Simulation and Embodied Instruction in Physics Learning

ERIC Educational Resources Information Center

Han, In Sook

2010-01-01

The purpose of this study was to investigate the potentials and effects of an embodied instructional model in abstract concept learning. This embodied instructional process included haptic augmented educational simulation as an instructional tool to provide perceptual experiences as well as further instruction to activate those previous…

Affordances of Augmented Reality in Science Learning: Suggestions for Future Research

ERIC Educational Resources Information Center

Cheng, Kun-Hung; Tsai, Chin-Chung

2013-01-01

Augmented reality (AR) is currently considered as having potential for pedagogical applications. However, in science education, research regarding AR-aided learning is in its infancy. To understand how AR could help science learning, this review paper firstly has identified two major approaches of utilizing AR technology in science education,…

Augmented Reality Games: Using Technology on a Budget

ERIC Educational Resources Information Center

Annetta, Leonard; Burton, Erin Peters; Frazier, Wendy; Cheng, Rebecca; Chmiel, Margaret

2012-01-01

As smartphones become more ubiquitous among adolescents, there is increasing potential for these as a tool to engage students in science instruction through innovative learning environments such as augmented reality (AR). Aligned with the National Science Education Standards (NRC 1996) and integrating the three dimensions of "A Framework for K-12…

Correlation of pull-out strength of cement-augmented pedicle screws with CT-volumetric measurement of cement.

PubMed

Fölsch, Christian; Goost, Hans; Figiel, Jens; Paletta, Jürgen R J; Schultz, Wolfgang; Lakemeier, Stefan

2012-12-01

Cement augmentation of pedicle screws increases fixation strength in an osteoporotic spine. This study was designed to determine the cement distribution and the correlation between the pull-out strength of the augmented screw and the cement volume within polyurethane (PU) foam. Twenty-eight cannulated pedicle screws (6×45 mm) (Peter Brehm, Erlangen, Germany) with four holes at the distal end of the screw were augmented with the acrylic Stabilit ER Bone Cement Vertebral Augmentation System (DFine Inc., San Jose, CA, USA) and implanted into open-cell rigid PU foam (Pacific Research Laboratories, Vashon Island, WA, USA) with a density of 0.12 g/cm3, resembling severe osteoporosis. Volumetric measurement of the cement with consideration of the distribution around the screws was done with multislice computed tomography scan (Somatom Definition, Siemens, Erlangen, Germany). Pull-out strength was tested with a servohydraulic system (MTS System Corporation, Eden Prairie, MN, USA), and nonaugmented screws served as control. Pearson's correlation coefficient with significance level α=0.05 and one-way analysis of variance test were used. We found a high (r=0.88) and significant (p<0.01) correlation between the cement volume and the pull-out strength, which increased by more than 5-fold with a volume of 3 ml. The correlation appeared linear at least up to 4 ml cement volume and failure always occurred at the cement-bone interface. The cement distribution was symmetric and circular around the most proximal hole, with a distance of 14 mm from the tip, and nearly 90% of the cement was found 6 mm distal and cranial to it. The 95% confidence interval for the relative amount of cement was 37%-41% within 2 mm of the most proximal hole. Compared with the control, a cement volume between 2.0 and 3.0 ml increased the pull-out strength significantly and is relevant for clinical purposes, whereas a volume of 0.5 ml did not. A cement volume beyond 3.0 ml should further increase the pull-out strength because the correlation was linear at least up to 4.0 ml, but the possibility of in vivo cement leakage with increasing volume has to be considered. Pressure-controlled cement application might be a tool to avoid this complication. The cement almost completely penetrated the most proximal perforation.

Electronic band structure of LaCoO3/Y/Mn compounds

NASA Astrophysics Data System (ADS)

Rahnamaye Aliabad, H. A.; Hesam, V.; Ahmad, Iftikhar; Khan, Imad

2013-02-01

Spin polarization effects on electronic properties of pure LaCoO3 and doped compounds (La0.5Y0.5CoO3, LaCo0.5Mn0.5O3) in the rhombohedral phase have been studied. We have employed the full potential linearized augmented plane wave (FP-LAPW) method with the generalized gradient approximation (GGA+U) under density functional theory (DFT). The calculated band structures along with total as well as partial densities of states reveal that Y and Mn impurities have a significant effect on the structural and electronic properties of LaCoO3. It is found that Mn alters insulating behavior of this compound to the half metallic for spin up state. Obtained results show that the magnetic moment for the Co-3d state is near 3.12μB in LaCoO3 compound which increases and decreases with addition of Y and Mn dopants respectively.

Adsorption and Dissociation of Molecular Oxygen on the (0001) Surface of Double Hexagonal Close Packed Americium

NASA Astrophysics Data System (ADS)

Dholabhai, Pratik; Atta-Fynn, Raymond; Ray, Asok

2008-03-01

Oxygen molecule adsorption on (0001) surface of double hexagonal packed americium has been studied in detail within the framework of density functional theory using a full-potential all-electron linearized augmented plane wave plus local orbitals method. The most stable configuration corresponded to molecular dissociation with the oxygen atoms occupying neighboring three-fold hollow h3 sites. Chemisorption energies and adsorption geometries for the adsorbed species, and change in work functions, magnetic moments, partial charges inside muffin-tins, difference charge density distributions and density of states for the bare Am slab and the Am slab after adsorption of the oxygen molecule will be discussed. The effects of chemisorption on Am 5f electron localization-delocalization in the vicinity of the Fermi level and the reaction barrier calculation for the dissociation of oxygen molecule to the most stable h3 sites will be discussed.

A Density Functional Study of Atomic Hydrogen and Oxygen Chemisorptions on the (0001) Surface of Double Hexagonal Close Packed Americium

NASA Astrophysics Data System (ADS)

Dholabhai, Pratik; Atta-Fynn, Raymond; Ray, Asok

2008-03-01

Ab initio total energy calculations within the framework of density functional theory have been performed for atomic hydrogen and oxygen chemisorptions on the (0001) surface of double hexagonal packed americium using a full-potential all-electron linearized augmented plane wave plus local orbitals (FLAPW+lo) method. The three-fold hollow hcp site was found to be the most stable site for H adsorption, while the two-fold bridge adsorption site was found to be the most stable site for O adsorption. Chemisorption energies and adsorption geometries for different adsorption sites will be discussed. The change in work functions, magnetic moments, partial charges inside muffin-tins, difference charge density distributions and density of states for the bare Am slab and the Am slab after adsorption of the adatom will be discussed. The implications of chemisorption on Am 5f electron localization-delocalization will also be discussed.

Half-metallicity and tetragonal distortion in semi-Heusler alloy FeCrSe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, H. M., E-mail: smilehhm@163.com; Luo, S. J.; Yao, K. L.

2014-01-28

Full-potential linearized augmented plane wave methods are carried out to investigate the electronic structures and magnetic properties in semi-Heusler alloy FeCrSe. Results show that FeCrSe is half-metallic ferromagnet with the half-metallic gap 0.31 eV at equilibrium lattice constant. Calculated total magnetic moment of 2.00μ{sub B} per formula unit follows the Slater-Pauling rule quite well. Two kinds of structural changes are used to investigate the sensitivity of half-metallicity. It is found that the half-metallicity can be retained when lattice constant is changed by −4.56% to 3.52%, and the results of tetragonal distortion indicate the half-metallicity can be kept at the range ofmore » c/a ratio from 0.85 to 1.20. The Curie temperature, cohesive energy, and heat of formations of FeCrSe are also discussed.« less

A Driving Behaviour Model of Electrical Wheelchair Users

PubMed Central

Hamam, Y.; Djouani, K.; Daachi, B.; Steyn, N.

2016-01-01

In spite of the presence of powered wheelchairs, some of the users still experience steering challenges and manoeuvring difficulties that limit their capacity of navigating effectively. For such users, steering support and assistive systems may be very necessary. To appreciate the assistance, there is need that the assistive control is adaptable to the user's steering behaviour. This paper contributes to wheelchair steering improvement by modelling the steering behaviour of powered wheelchair users, for integration into the control system. More precisely, the modelling is based on the improved Directed Potential Field (DPF) method for trajectory planning. The method has facilitated the formulation of a simple behaviour model that is also linear in parameters. To obtain the steering data for parameter identification, seven individuals participated in driving the wheelchair in different virtual worlds on the augmented platform. The obtained data facilitated the estimation of user parameters, using the ordinary least square method, with satisfactory regression analysis results. PMID:27148362

Optical properties of rhodamine 6G-doped TiO2 sol-gel films

NASA Astrophysics Data System (ADS)

Tomás, S. A.; Stolik, S.; Palomino, R.; Lozada, R.; Persson, C.; Ahuja, R.; Pepe, I.; Ferreira da Silva, A.

2005-06-01

The optical properties of titania (TiO2) thin films prepared by the sol-gel process and doped with rhodamine 6G were studied by Photoacoustic Spectroscopy. Rhodamine 6G-doping was achieved by adding 0.01%, 0.02%, 0.05% y 0.1% mol rhodamine to a solution that contained titanium isopropoxide as precursor. Two absorption regions were distinguished in the absorption spectrum of a typical rhodamine 6G-doped TiO2 film. A shift of these bands occured as a function of rhodamine 6G-doping concentration. In addition, the optical absorption and band gap energy for rutile-phase TiO2 films were calculated employing the full-potential linearized augmented plane wave method. A comparison of these calculations with experimental data of TiO2 films prepared by sol-gel at room temperature was performed.

Charge transfer mechanism for the formation of metallic states at the KTaO3/SrTiO3 interface

NASA Astrophysics Data System (ADS)

Nazir, S.; Singh, N.; Schwingenschlögl, U.

2011-03-01

The electronic and optical properties of the KTaO3/SrTiO3 heterointerface are analyzed by the full-potential linearized augmented plane-wave approach of density functional theory. Optimization of the atomic positions points at subordinate changes in the crystal structure and chemical bonding near the interface, which is due to a minimal lattice mismatch. The creation of metallic interface states thus is not affected by structural relaxation but can be explained by charge transfer between transition metal and oxygen atoms. It is to be expected that a charge transfer is likewise important for related interfaces such as LaAlO3/SrTiO3. The KTaO3/SrTiO3 system is ideal for disentangling the complex behavior of metallic interface states, since almost no structural relaxation takes place.

Electronic and optical properties of Praseodymium trifluoride

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saini, Sapan Mohan, E-mail: smsaini.phy@nitrr.ac.in

2014-10-24

We report the role of f- states on electronic and optical properties of Praseodymium trifluoride (PrF{sub 3}) compound. Full potential linearized augmented plane wave (FPLAPW) method with the inclusion of spin orbit coupling has been used. We employed the local spin density approximation (LSDA) and Coulomb-corrected local spin density approximation (LSDA+U). LSDA+U is known for treating the highly correlated 4f electrons properly. Our theoretical investigation shows that LSDA+U approximation reproduce the correct insulating ground state of PrF{sub 3}. On the other hand there is no significant difference of reflectivity calculated by LSDA and LSDA+U. We find that the reflectivity formore » PrF{sub 3} compound stays low till around 7 eV which is consistent with their large energy gaps. Our calculated reflectivity compares well with the experimental data. The results are analyzed in the light of transitions involved.« less

Relaxation of Actinide Surfaces: An All Electron Study

NASA Astrophysics Data System (ADS)

Atta-Fynn, Raymond; Dholabhai, Pratik; Ray, Asok

2006-10-01

Fully relativistic full potential density functional calculations with a linearized augmented plane wave plus local orbitals basis (LAPW + lo) have been performed to investigate the relaxations of heavy actinide surfaces, namely the (111) surface of fcc δ-Pu and the (0001) surface of dhcp Am using WIEN2k. This code uses the LAPW + lo method with the unit cell divided into non-overlapping atom-centered spheres and an interstitial region. The APW+lo basis is used to describe all s, p, d, and f states and LAPW basis to describe all higher angular momentum states. Each surface was modeled by a three-layer periodic slab separated by 60 Bohr vacuum with four atoms per surface unit cell. In general, we have found a contraction of the interlayer separations for both Pu and Am. We will report, in detail, the electronic and geometric structures of the relaxed surfaces and comparisons with the respective non-relaxed surfaces.

Ab initio study on structural stability of uranium carbide

NASA Astrophysics Data System (ADS)

Sahoo, B. D.; Joshi, K. D.; Gupta, Satish C.

2013-06-01

First principles calculations have been performed using plane wave pseudopotential and full potential linearized augmented plane wave (FP-LAPW) methods to analyze structural, elastic and dynamic stability of UC under hydrostatic compression. Our calculations within pseudopotential method suggest that the rocksalt (B1) structure will transform to body centered orthorhombic (bco) structure at ˜21.5 GPa. The FP-LAPW calculations put this transition at 23 GPa. The transition pressures determined from our calculations though agree reasonably with the experimental value of 27 GPa, the high pressure bco structure suggested by theory differs slightly from the experimentally reported pseudo bco phase. The elastic stability analysis of B1 phase suggests that the B1 to bco transition is driven by the failure of C44 modulus. This finding is further substantiated by the lattice dynamic calculations which demonstrate that the B1 phase becomes dynamically unstable around the transition pressure and the instability is of long wavelength nature.

Magneto-optical spectroscopy of Co{sub 2}FeSi Heusler compound

DOE Office of Scientific and Technical Information (OSTI.GOV)

Veis, M., E-mail: veis@karlov.mff.cuni.cz; Beran, L.; Antos, R.

2014-05-07

Magneto-optical and electronic properties of the Co{sub 2}FeSi Heusler compound were studied by polar Kerr magneto-optical spectroscopy and ab-initio calculations. The thin-film samples were grown by dc/rf magnetron co-sputtering on MgO(100) substrates. A Cr seed layer was deposited prior to the Co{sub 2}FeSi layer to achieve its epitaxial growth. The magneto-optical spectroscopy was carried out using generalized magneto-optical ellipsometry with rotating analyzer in the photon energy range from 1.4 to 5.5 eV with an applied magnetic field of up to 1.2 T. The polar Kerr spectra showed a smooth spectral behavior up to 5.5 eV indicating nearly free charge carriers. Experimental data weremore » compared with ab-initio calculations based on density functional theory employing the full-potential linearized augmented plane wave method.« less

Transforming Experience: The Potential of Augmented Reality and Virtual Reality for Enhancing Personal and Clinical Change

PubMed Central

Riva, Giuseppe; Baños, Rosa M.; Botella, Cristina; Mantovani, Fabrizia; Gaggioli, Andrea

2016-01-01

During life, many personal changes occur. These include changing house, school, work, and even friends and partners. However, the daily experience shows clearly that, in some situations, subjects are unable to change even if they want to. The recent advances in psychology and neuroscience are now providing a better view of personal change, the change affecting our assumptive world: (a) the focus of personal change is reducing the distance between self and reality (conflict); (b) this reduction is achieved through (1) an intense focus on the particular experience creating the conflict or (2) an internal or external reorganization of this experience; (c) personal change requires a progression through a series of different stages that however happen in discontinuous and non-linear ways; and (d) clinical psychology is often used to facilitate personal change when subjects are unable to move forward. Starting from these premises, the aim of this paper is to review the potential of virtuality for enhancing the processes of personal and clinical change. First, the paper focuses on the two leading virtual technologies – augmented reality (AR) and virtual reality (VR) – exploring their current uses in behavioral health and the outcomes of the 28 available systematic reviews and meta-analyses. Then the paper discusses the added value provided by VR and AR in transforming our external experience by focusing on the high level of personal efficacy and self-reflectiveness generated by their sense of presence and emotional engagement. Finally, it outlines the potential future use of virtuality for transforming our inner experience by structuring, altering, and/or replacing our bodily self-consciousness. The final outcome may be a new generation of transformative experiences that provide knowledge that is epistemically inaccessible to the individual until he or she has that experience, while at the same time transforming the individual’s worldview. PMID:27746747

Transforming Experience: The Potential of Augmented Reality and Virtual Reality for Enhancing Personal and Clinical Change.

PubMed

Riva, Giuseppe; Baños, Rosa M; Botella, Cristina; Mantovani, Fabrizia; Gaggioli, Andrea

2016-01-01

During life, many personal changes occur. These include changing house, school, work, and even friends and partners. However, the daily experience shows clearly that, in some situations, subjects are unable to change even if they want to. The recent advances in psychology and neuroscience are now providing a better view of personal change, the change affecting our assumptive world: (a) the focus of personal change is reducing the distance between self and reality (conflict); (b) this reduction is achieved through (1) an intense focus on the particular experience creating the conflict or (2) an internal or external reorganization of this experience; (c) personal change requires a progression through a series of different stages that however happen in discontinuous and non-linear ways; and (d) clinical psychology is often used to facilitate personal change when subjects are unable to move forward. Starting from these premises, the aim of this paper is to review the potential of virtuality for enhancing the processes of personal and clinical change. First, the paper focuses on the two leading virtual technologies - augmented reality (AR) and virtual reality (VR) - exploring their current uses in behavioral health and the outcomes of the 28 available systematic reviews and meta-analyses. Then the paper discusses the added value provided by VR and AR in transforming our external experience by focusing on the high level of personal efficacy and self-reflectiveness generated by their sense of presence and emotional engagement. Finally, it outlines the potential future use of virtuality for transforming our inner experience by structuring, altering, and/or replacing our bodily self-consciousness. The final outcome may be a new generation of transformative experiences that provide knowledge that is epistemically inaccessible to the individual until he or she has that experience, while at the same time transforming the individual's worldview.

First-principles study of the structural, electronic and thermal properties of CaLiF3

NASA Astrophysics Data System (ADS)

Chouit, N.; Amara Korba, S.; Slimani, M.; Meradji, H.; Ghemid, S.; Khenata, R.

2013-09-01

Density functional theory calculations have been performed to study the structural, electronic and optical properties of CaLiF3 cubic fluoroperovskite. Our calculations were carried out by means of the full-potential linearized augmented plane-wave method. The exchange-correlation potential is treated by the local density approximation and the generalized gradient approximation (GGA) (Perdew, Burke and Ernzerhof). Moreover, the alternative form of GGA proposed by Engel and Vosko is also used for band structure calculations. The calculated total energy versus volume allows us to obtain structural properties such as the lattice constant (a0), bulk modulus (B0) and pressure derivative of the bulk modulus (B'0 ). Band structure, density of states and band gap pressure coefficients are also given. Our calculations show that CaLiF3 has an indirect band gap (R-Γ). Following the quasi-harmonic Debye model, in which the phononic effects are considered, the temperature and pressure effects on the lattice constant, bulk modulus, thermal expansion coefficient, Debye temperature and heat capacities are calculated.

First-principles calculations of two cubic fluoropervskite compounds: RbFeF3 and RbNiF3

NASA Astrophysics Data System (ADS)

Mubarak, A. A.; Al-Omari, Saleh

2015-05-01

We present first-principles calculations of the structural, elastic, electronic, magnetic and optical properties for RbFeF3 and RbNiF3. The full-potential linear augmented plan wave (FP-LAPW) method within the density functional theory was utilized to perform the present calculations. We employed the generalized gradient approximation as exchange-correlation potential. It was found that the calculated analytical lattice parameters agree with previous studies. The analysis of elastic constants showed that the present compounds are elastically stable and anisotropic. Moreover, both compounds are classified as a ductile compound. The calculations of the band structure and density functional theory revealed that the RbFeF3 compound has a half-metallic behavior while the RbNiF3 compound has a semiconductor behavior with indirect (M-Γ) band gap. The ferromagnetic behavior was studied for both compounds. The optical properties were calculated for the radiation of up to 40 eV. A beneficial optics technology is predicted as revealed from the optical spectra.

Addition of deep brain stimulation signal to a local field potential driven Izhikevich model masks the pathological firing pattern of an STN neuron.

PubMed

Michmizos, Kostis P; Nikita, Konstantina S

2011-01-01

The crucial engagement of the subthalamic nucleus (STN) with the neurosurgical procedure of deep brain stimulation (DBS) that alleviates medically intractable Parkinsonian tremor augments the need to refine our current understanding of STN. To enhance the efficacy of DBS as a result of precise targeting, STN boundaries are accurately mapped using extracellular microelectrode recordings (MERs). We utilized the intranuclear MER to acquire the local field potential (LFP) and drive an Izhikevich model of an STN neuron. Using the model as the test bed for clinically acquired data, we demonstrated that stimulation of the STN neuron produces excitatory responses that tonically increase its average firing rate and alter the pattern of its neuronal activity. We also found that the spiking rhythm increases linearly with the increase of amplitude, frequency, and duration of the DBS pulse, inside the clinical range. Our results are in agreement with the current hypothesis that DBS increases the firing rate of STN and masks its pathological bursting firing pattern.

Electron-phonon coupling and superconductivity in MgB2 under hydrostatic pressure.

NASA Astrophysics Data System (ADS)

Quijano, Ramiro; Aguayo, Aaron

2005-03-01

We have studied the dynamics and coupling of the E2g phonon mode with the σ-band in MgB2 under pressure using the Frozen Phonon Approximation. The results were obtained by means of first-principles total-energy calculations using the full potential Linearized Augmented Plane Wave (LAPW) method and the Generalized Gradient Approximation (GGA) for the exchange-correlation potential. We present results for the evolution of the anharmonicity and phonon frequency of the E2g mode, the electron-phonon coupling constant, and Tc as a function of hydrostatic pressure in the range 0-40 GPa. We find that the phonon frequency increases monotonically with pressure, but the the anharmonicity, the electron-phonon coupling and Tc decreases with pressure. We have obtained a very good agreement between the calculated Tc(P) and the experimental data available in the literature, in particular with the experimental data corresponding to monocystalline samples. This work was supported by Consejo Nacional de Ciencia y Tecnolog'ia (CONACYT, M'exico) under Grant No. 43830-F.

First-Principles Study of the Electronic Structure and Bonding Properties of X8C46 and X8B6C40 (X: Li, Na, Mg, Ca) Carbon Clathrates

NASA Astrophysics Data System (ADS)

KoleŻyński, Andrzej; Szczypka, Wojciech

2016-03-01

Results from theoretical analysis of the crystal structure, electronic structure, and bonding properties of C46 and B6C40 carbon clathrates doped with selected alkali and alkaline earth metals cations (Li, Na, Mg, Ca) are presented. The ab initio calculations were performed by means of the WIEN2k package (full potential linearized augmented plane wave method (FP-LAPW) within density functional theory (DFT)) with PBESol and modified Becke-Johnson exchange-correlation potentials used in geometry optimization and electronic structure calculations, respectively. The bonding properties were analyzed by applying Bader's quantum theory of atoms in molecules formalism to the topological properties of total electron density obtained from ab initio calculations. Analysis of the results obtained (i.a. equilibrium geometry, equation of state, cohesive energy, band structure, density of states—both total and projected on to particular atoms, and topological properties of bond critical points and net charges of topological atoms) is presented in detail.

Augmented Reality-Guided Lumbar Facet Joint Injections.

PubMed

Agten, Christoph A; Dennler, Cyrill; Rosskopf, Andrea B; Jaberg, Laurenz; Pfirrmann, Christian W A; Farshad, Mazda

2018-05-08

The aim of this study was to assess feasibility and accuracy of augmented reality-guided lumbar facet joint injections. A spine phantom completely embedded in hardened opaque agar with 3 ring markers was built. A 3-dimensional model of the phantom was uploaded to an augmented reality headset (Microsoft HoloLens). Two radiologists independently performed 20 augmented reality-guided and 20 computed tomography (CT)-guided facet joint injections each: for each augmented reality-guided injection, the hologram was manually aligned with the phantom container using the ring markers. The radiologists targeted the virtual facet joint and tried to place the needle tip in the holographic joint space. Computed tomography was performed after each needle placement to document final needle tip position. Time needed from grabbing the needle to final needle placement was measured for each simulated injection. An independent radiologist rated images of all needle placements in a randomized order blinded to modality (augmented reality vs CT) and performer as perfect, acceptable, incorrect, or unsafe. Accuracy and time to place needles were compared between augmented reality-guided and CT-guided facet joint injections. In total, 39/40 (97.5%) of augmented reality-guided needle placements were either perfect or acceptable compared with 40/40 (100%) CT-guided needle placements (P = 0.5). One augmented reality-guided injection missed the facet joint space by 2 mm. No unsafe needle placements occurred. Time to final needle placement was substantially faster with augmented reality guidance (mean 14 ± 6 seconds vs 39 ± 15 seconds, P < 0.001 for both readers). Augmented reality-guided facet joint injections are feasible and accurate without potentially harmful needle placement in an experimental setting.

Control by model error estimation

NASA Technical Reports Server (NTRS)

Likins, P. W.; Skelton, R. E.

1976-01-01

Modern control theory relies upon the fidelity of the mathematical model of the system. Truncated modes, external disturbances, and parameter errors in linear system models are corrected by augmenting to the original system of equations an 'error system' which is designed to approximate the effects of such model errors. A Chebyshev error system is developed for application to the Large Space Telescope (LST).

GPU implementation of the simplex identification via split augmented Lagrangian

NASA Astrophysics Data System (ADS)

Sevilla, Jorge; Nascimento, José M. P.

2015-10-01

Hyperspectral imaging can be used for object detection and for discriminating between different objects based on their spectral characteristics. One of the main problems of hyperspectral data analysis is the presence of mixed pixels, due to the low spatial resolution of such images. This means that several spectrally pure signatures (endmembers) are combined into the same mixed pixel. Linear spectral unmixing follows an unsupervised approach which aims at inferring pure spectral signatures and their material fractions at each pixel of the scene. The huge data volumes acquired by such sensors put stringent requirements on processing and unmixing methods. This paper proposes an efficient implementation of a unsupervised linear unmixing method on GPUs using CUDA. The method finds the smallest simplex by solving a sequence of nonsmooth convex subproblems using variable splitting to obtain a constraint formulation, and then applying an augmented Lagrangian technique. The parallel implementation of SISAL presented in this work exploits the GPU architecture at low level, using shared memory and coalesced accesses to memory. The results herein presented indicate that the GPU implementation can significantly accelerate the method's execution over big datasets while maintaining the methods accuracy.

Augmented switching linear dynamical system model for gas concentration estimation with MOX sensors in an open sampling system.

PubMed

Di Lello, Enrico; Trincavelli, Marco; Bruyninckx, Herman; De Laet, Tinne

2014-07-11

In this paper, we introduce a Bayesian time series model approach for gas concentration estimation using Metal Oxide (MOX) sensors in Open Sampling System (OSS). Our approach focuses on the compensation of the slow response of MOX sensors, while concurrently solving the problem of estimating the gas concentration in OSS. The proposed Augmented Switching Linear System model allows to include all the sources of uncertainty arising at each step of the problem in a single coherent probabilistic formulation. In particular, the problem of detecting on-line the current sensor dynamical regime and estimating the underlying gas concentration under environmental disturbances and noisy measurements is formulated and solved as a statistical inference problem. Our model improves, with respect to the state of the art, where system modeling approaches have been already introduced, but only provided an indirect relative measures proportional to the gas concentration and the problem of modeling uncertainty was ignored. Our approach is validated experimentally and the performances in terms of speed of and quality of the gas concentration estimation are compared with the ones obtained using a photo-ionization detector.

Augmented Switching Linear Dynamical System Model for Gas Concentration Estimation with MOX Sensors in an Open Sampling System

PubMed Central

Di Lello, Enrico; Trincavelli, Marco; Bruyninckx, Herman; De Laet, Tinne

2014-01-01

In this paper, we introduce a Bayesian time series model approach for gas concentration estimation using Metal Oxide (MOX) sensors in Open Sampling System (OSS). Our approach focuses on the compensation of the slow response of MOX sensors, while concurrently solving the problem of estimating the gas concentration in OSS. The proposed Augmented Switching Linear System model allows to include all the sources of uncertainty arising at each step of the problem in a single coherent probabilistic formulation. In particular, the problem of detecting on-line the current sensor dynamical regime and estimating the underlying gas concentration under environmental disturbances and noisy measurements is formulated and solved as a statistical inference problem. Our model improves, with respect to the state of the art, where system modeling approaches have been already introduced, but only provided an indirect relative measures proportional to the gas concentration and the problem of modeling uncertainty was ignored. Our approach is validated experimentally and the performances in terms of speed of and quality of the gas concentration estimation are compared with the ones obtained using a photo-ionization detector. PMID:25019637

Stochastic modeling of mode interactions via linear parabolized stability equations

NASA Astrophysics Data System (ADS)

Ran, Wei; Zare, Armin; Hack, M. J. Philipp; Jovanovic, Mihailo

2017-11-01

Low-complexity approximations of the Navier-Stokes equations have been widely used in the analysis of wall-bounded shear flows. In particular, the parabolized stability equations (PSE) and Floquet theory have been employed to capture the evolution of primary and secondary instabilities in spatially-evolving flows. We augment linear PSE with Floquet analysis to formally treat modal interactions and the evolution of secondary instabilities in the transitional boundary layer via a linear progression. To this end, we leverage Floquet theory by incorporating the primary instability into the base flow and accounting for different harmonics in the flow state. A stochastic forcing is introduced into the resulting linear dynamics to model the effect of nonlinear interactions on the evolution of modes. We examine the H-type transition scenario to demonstrate how our approach can be used to model nonlinear effects and capture the growth of the fundamental and subharmonic modes observed in direct numerical simulations and experiments.

Topiramate in schizophrenia: a review of effects on psychopathology and metabolic parameters.

PubMed

Hahn, Margaret K; Cohn, Tony; Teo, Celine; Remington, Gary

2013-01-01

Less than half of patients with schizophrenia obtain full response to antipsychotic drugs and, while clozapine represents the treatment of choice for refractory psychosis, a significant number of individuals remain only partially responsive. Despite a need for augmentation in this subpopulation, to date clear choices have not been forthcoming. Because clozapine, along with the majority of second-generation agents (SGAs), are linked to metabolic disturbances, augmentation strategies that do not further exacerbate these side effects are needed. Topiramate, unlike other anticonvulsants used for augmentation purposes, has been associated with weight loss. This article reviews the safety and efficacy of topiramate in treatment-refractory schizophrenia, including effects on metabolic disturbances, which burden this population. While current evidence specifically examining improvements in psychopathology demonstrates small to moderate benefits with topiramate augmentation, a growing body of evidence suggests that topiramate may have beneficial effects on antipsychotic-induced weight gain. We conclude that topiramate's metabolic profile, taken together with a current lack of evidence supporting a particular augmentation strategy, argues for further well-controlled studies examining its potential as an augmentation strategy in schizophrenia.

Novel Augmentation Technique for Patellar Tendon Repair Improves Strength and Decreases Gap Formation: A Cadaveric Study.

PubMed

Black, James C; Ricci, William M; Gardner, Michael J; McAndrew, Christopher M; Agarwalla, Avinesh; Wojahn, Robert D; Abar, Orchid; Tang, Simon Y

2016-12-01

Patellar tendon ruptures commonly are repaired using transosseous patellar drill tunnels with modified-Krackow sutures in the patellar tendon. This simple suture technique has been associated with failure rates and poor clinical outcomes in a modest proportion of patients. Failure of this repair technique can result from gap formation during loading or a single catastrophic event. Several augmentation techniques have been described to improve the integrity of the repair, but standardized biomechanical evaluation of repair strength among different techniques is lacking. The purpose of this study was to describe a novel figure-of-eight suture technique to augment traditional fixation and evaluate its biomechanical performance. We hypothesized that the augmentation technique would (1) reduce gap formation during cyclic loading and (2) increase the maximum load to failure. Ten pairs (two male, eight female) of fresh-frozen cadaveric knees free of overt disorders or patellar tendon damage were used (average donor age, 76 years; range, 65-87 years). For each pair, one specimen underwent the standard transosseous tunnel suture repair with a modified-Krackow suture technique and the second underwent the standard repair with our experimental augmentation method. Nine pairs were suitable for testing. Each specimen underwent cyclic loading while continuously measuring gap formation across the repair. At the completion of cyclic loading, load to failure testing was performed. A difference in gap formation and mean load to failure was seen in favor of the augmentation technique. At 250 cycles, a 68% increase in gap formation was seen for the control group (control: 5.96 ± 0.86 mm [95% CI, 5.30-6.62 mm]; augmentation: 3.55 ± 0.56 mm [95% CI, 3.12-3.98 mm]; p = 0.02). The mean load to failure was 13% greater in the augmentation group (control: 899.57 ± 96.94 N [95% CI, 825.06-974.09 N]; augmentation: 1030.70 ± 122.41 N [95% CI, 936.61-1124.79 N]; p = 0.01). This biomechanical study showed improved performance of a novel augmentation technique compared with the standard repair, in terms of reduced gap formation during cyclic loading and increased maximum load to failure. Decreased gap formation and higher load to failure may improve healing potential and minimize failure risk. This study shows a potential biomechanical advantage of the augmentation technique, providing support for future clinical investigations comparing this technique with other repair methods that are in common use such as transosseous suture repair.

Making the Invisible Visible in Science Museums through Augmented Reality Devices

ERIC Educational Resources Information Center

Yoon, Susan A.; Wang, Joyce

2014-01-01

Despite the potential of augmented reality (AR) in enabling students to construct new understanding, little is known about how the processes and interactions with the multimedia lead to increased learning. This study seeks to explore the affordances of an AR tool on learning that is focused on the science concept of magnets and magnetic fields.…

Pedagogical and Technological Augmentation of Mobile Learning for Young Children Interactive Learning Environments

ERIC Educational Resources Information Center

Kim, Yanghee; Smith, Diantha

2017-01-01

The ubiquity and educational potential of mobile applications are well acknowledged. This paper proposes six theory-based, pedagogical strategies to guide interaction design of mobile apps for young children. Also, to augment the capabilities of mobile devices, we used a humanoid robot integrated with a smartphone and developed an English-learning…

Pilots Rate Augmented Generalized Predictive Control for Reconfiguration

NASA Technical Reports Server (NTRS)

Soloway, Don; Haley, Pam

2004-01-01

The objective of this paper is to report the results from the research being conducted in reconfigurable fight controls at NASA Ames. A study was conducted with three NASA Dryden test pilots to evaluate two approaches of reconfiguring an aircraft's control system when failures occur in the control surfaces and engine. NASA Ames is investigating both a Neural Generalized Predictive Control scheme and a Neural Network based Dynamic Inverse controller. This paper highlights the Predictive Control scheme where a simple augmentation to reduce zero steady-state error led to the neural network predictor model becoming redundant for the task. Instead of using a neural network predictor model, a nominal single point linear model was used and then augmented with an error corrector. This paper shows that the Generalized Predictive Controller and the Dynamic Inverse Neural Network controller perform equally well at reconfiguration, but with less rate requirements from the actuators. Also presented are the pilot ratings for each controller for various failure scenarios and two samples of the required control actuation during reconfiguration. Finally, the paper concludes by stepping through the Generalized Predictive Control's reconfiguration process for an elevator failure.

Identifiability of Additive, Time-Varying Actuator and Sensor Faults by State Augmentation

NASA Technical Reports Server (NTRS)

Upchurch, Jason M.; Gonzalez, Oscar R.; Joshi, Suresh M.

2014-01-01

Recent work has provided a set of necessary and sucient conditions for identifiability of additive step faults (e.g., lock-in-place actuator faults, constant bias in the sensors) using state augmentation. This paper extends these results to an important class of faults which may affect linear, time-invariant systems. In particular, the faults under consideration are those which vary with time and affect the system dynamics additively. Such faults may manifest themselves in aircraft as, for example, control surface oscillations, control surface runaway, and sensor drift. The set of necessary and sucient conditions presented in this paper are general, and apply when a class of time-varying faults affects arbitrary combinations of actuators and sensors. The results in the main theorems are illustrated by two case studies, which provide some insight into how the conditions may be used to check the theoretical identifiability of fault configurations of interest for a given system. It is shown that while state augmentation can be used to identify certain fault configurations, other fault configurations are theoretically impossible to identify using state augmentation, giving practitioners valuable insight into such situations. That is, the limitations of state augmentation for a given system and configuration of faults are made explicit. Another limitation of model-based methods is that there can be large numbers of fault configurations, thus making identification of all possible configurations impractical. However, the theoretical identifiability of known, credible fault configurations can be tested using the theorems presented in this paper, which can then assist the efforts of fault identification practitioners.

Comparative study of flare control laws. [optimal control of b-737 aircraft approach and landing

NASA Technical Reports Server (NTRS)

Nadkarni, A. A.; Breedlove, W. J., Jr.

1979-01-01

A digital 3-D automatic control law was developed to achieve an optimal transition of a B-737 aircraft between various initial glid slope conditions and the desired final touchdown condition. A discrete, time-invariant, optimal, closed-loop control law presented for a linear regulator problem, was extended to include a system being acted upon by a constant disturbance. Two forms of control laws were derived to solve this problem. One method utilized the feedback of integral states defined appropriately and augmented with the original system equations. The second method formulated the problem as a control variable constraint, and the control variables were augmented with the original system. The control variable constraint control law yielded a better performance compared to feedback control law for the integral states chosen.

The design and implementation of cost-effective algorithms for direct solution of banded linear systems on the vector processor system 32 supercomputer

NASA Technical Reports Server (NTRS)

Samba, A. S.

1985-01-01

The problem of solving banded linear systems by direct (non-iterative) techniques on the Vector Processor System (VPS) 32 supercomputer is considered. Two efficient direct methods for solving banded linear systems on the VPS 32 are described. The vector cyclic reduction (VCR) algorithm is discussed in detail. The performance of the VCR on a three parameter model problem is also illustrated. The VCR is an adaptation of the conventional point cyclic reduction algorithm. The second direct method is the Customized Reduction of Augmented Triangles' (CRAT). CRAT has the dominant characteristics of an efficient VPS 32 algorithm. CRAT is tailored to the pipeline architecture of the VPS 32 and as a consequence the algorithm is implicitly vectorizable.

Recombinant human bone morphogenetic protein 2 in augmentation procedures: case reports.

PubMed

Luiz, Jaques; Padovan, Luis Eduardo Marques; Claudino, Marcela

2014-01-01

To successfully rehabilitate edentulous patients using endosseous implants, there must be enough available bone. Several techniques have been proposed for augmentation of sites with insufficient bone volume. Although autogenous bone has long been considered the gold standard for such procedures, the limited availability of graft material and a high morbidity rate are potential disadvantages of this type of graft. An alternative is to use recombinant human bone morphogenetic protein 2 (rhBMP-2), which is able to support bone regeneration in the oral environment. These cases demonstrate the applicability of rhBMP-2 in maxillary sinus elevation and augmentation procedures in the maxilla to enable dental implant placement. The use of rhBMP-2 in alveolar augmentation procedures had several clinical benefits for these patients.

Generation of dark solitons and their instability dynamics in two-dimensional condensates

NASA Astrophysics Data System (ADS)

Verma, Gunjan; Rapol, Umakant D.; Nath, Rejish

2017-04-01

We analyze numerically the formation and the subsequent dynamics of two-dimensional matter wave dark solitons in a Thomas-Fermi rubidium condensate using various techniques. An initially imprinted sharp phase gradient leads to the dynamical formation of a stationary soliton as well as very shallow gray solitons, whereas a smooth gradient only creates gray solitons. The depth and hence, the velocity of the soliton is provided by the spatial width of the phase gradient, and it also strongly influences the snake-instability dynamics of the two-dimensional solitons. The vortex dipoles stemming from the unstable soliton exhibit rich dynamics. Notably, the annihilation of a vortex dipole via a transient dark lump or a vortexonium state, the exchange of vortices between either a pair of vortex dipoles or a vortex dipole and a single vortex, and so on. For sufficiently large width of the initial phase gradient, the solitons may decay directly into vortexoniums instead of vortex pairs, and also the decay rate is augmented. Later, we discuss alternative techniques to generate dark solitons, which involve a Gaussian potential barrier and time-dependent interactions, both linear and periodic. The properties of the solitons can be controlled by tuning the amplitude or the width of the potential barrier. In the linear case, the number of solitons and their depths are determined by the quench time of the interactions. For the periodic modulation, a transient soliton lattice emerges with its periodicity depending on the modulation frequency, through a wave number selection governed by the local Bogoliubov spectrum. Interestingly, for sufficiently low barrier potential, both Faraday pattern and soliton lattice coexist. The snake instability dynamics of the soliton lattice is characteristically modified if the Faraday pattern is present.

The augmented anticancer potential of AP9-cd loaded solid lipid nanoparticles in human leukemia Molt-4 cells and experimental tumor.

PubMed

Bhushan, Shashi; Kakkar, Vandita; Pal, Harish Chandra; Mondhe, D M; Kaur, Indu Pal

2016-01-25

AP9-cd, a novel lignan composition from Cedrus deodara has significant anticancer potential, and to further enhance its activity, it was lucratively encumbered into solid lipid nanoparticles (SLNs). These nanoparticles were formulated by micro-emulsion technique with 70% drug trap competence. AP9-cd-SLNs were regular, solid, globular particles in the range of 100-200 nm, which were confirmed by electron microscopic studies. Moreover, AP9-cd-SLNs were found to be stable for up to six months in terms of color, particle size, zeta potential, drug content and entrapment. AP9-cd-SLNs have 30-50% higher cytotoxic and apoptotic potential than the AP9-cd alone. The augmented anticancer potential of AP9-cd-SLNs was observed in cytotoxic IC50 value, apoptosis signaling cascade and in Ehrlich ascites tumor (EAT) model. AP9-cd-SLNs induce apoptosis in Molt-4 cells via both intrinsic and extrinsic pathway. Moreover, the dummy nanoparticles (SLNs without AP9-cd) did not have any cytotoxic effect in cancer as well as in normal cells. Consequently, SLNs of AP9-cd significantly augment the apoptotic and antitumor potential of AP9-cd. The present study provides a podium for ornamental the remedial latent via novel delivery systems like solid lipid nanoparticles. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

The Biomechanical and Histologic Effects of Platelet-Rich Plasma on Rat Rotator Cuff Repairs

PubMed Central

Beck, Jennifer; Evans, Douglas; Tonino, Pietro M.; Yong, Sherri; Callaci, John J.

2013-01-01

Background Rotator cuff tears are common injuries that are often treated with surgical repair. Because of the high concentration of growth factors within platelets, platelet-rich plasma (PRP) has the potential to enhance healing in rotator cuff repairs. Hypothesis Platelet-rich plasma would alter the biomechanical and histologic properties of rotator cuff repair during an acute injury response. Study Design Controlled laboratory study. Methods Platelet-rich plasma was produced from inbred donor rats. A tendon-from-bone supraspinatus tear was created surgically and an immediate transosseous repair performed. The control group underwent repair only. The PRP group underwent a repair with PRP augmentation. Rats in each group were sacrificed at 7, 14, and 21 days. The surgically repaired tendons underwent biomechanical testing, including failure load, stiffness, failure strain, and stress relaxation characteristics. Histological analysis evaluated the cellular characteristics of the repair tissue. Results At 7- and 21-day periods, augmentation with PRP showed statistically significant effects on the biomechanical properties of the repaired rat supraspinatus tear, but failure load was not increased at the 7-, 14-, or 21-day periods (P = .688, .209, and .477, respectively). The control group had significantly higher stiffness at 21 days (P = .006). The control group had higher failure strain at 7 days (P = .02), whereas the PRP group had higher failure strain at 21 days (P = .008). Histologically, the PRP group showed increased fibroblastic response and vascular proliferation at each time point. At 21 days, the collagen fibers in the PRP group were oriented in a more linear fashion toward the tendon footprint. Conclusion In this controlled, rat model study, PRP altered the tissue properties of the supraspinatus tendon without affecting the construct’s failure load. Clinical Relevance The decreased tendon tissue stiffness acutely and failure to enhance tendon-to-bone healing of repairs should be considered before augmenting rotator cuff repairs with PRP. Further studies will be necessary to determine the role of PRP in clinical practice. PMID:22822177

An augmented Lagrangian trust region method for inclusion boundary reconstruction using ultrasound/electrical dual-modality tomography

NASA Astrophysics Data System (ADS)

Liang, Guanghui; Ren, Shangjie; Dong, Feng

2018-07-01

The ultrasound/electrical dual-modality tomography utilizes the complementarity of ultrasound reflection tomography (URT) and electrical impedance tomography (EIT) to improve the speed and accuracy of image reconstruction. Due to its advantages of no-invasive, no-radiation and low-cost, ultrasound/electrical dual-modality tomography has attracted much attention in the field of dual-modality imaging and has many potential applications in industrial and biomedical imaging. However, the data fusion of URT and EIT is difficult due to their different theoretical foundations and measurement principles. The most commonly used data fusion strategy in ultrasound/electrical dual-modality tomography is incorporating the structured information extracted from the URT into the EIT image reconstruction process through a pixel-based constraint. Due to the inherent non-linearity and ill-posedness of EIT, the reconstructed images from the strategy suffer from the low resolution, especially at the boundary of the observed inclusions. To improve this condition, an augmented Lagrangian trust region method is proposed to directly reconstruct the shapes of the inclusions from the ultrasound/electrical dual-modality measurements. In the proposed method, the shape of the target inclusion is parameterized by a radial shape model whose coefficients are used as the shape parameters. Then, the dual-modality shape inversion problem is formulated by an energy minimization problem in which the energy function derived from EIT is constrained by an ultrasound measurements model through an equality constraint equation. Finally, the optimal shape parameters associated with the optimal inclusion shape guesses are determined by minimizing the constrained cost function using the augmented Lagrangian trust region method. To evaluate the proposed method, numerical tests are carried out. Compared with single modality EIT, the proposed dual-modality inclusion boundary reconstruction method has a higher accuracy and is more robust to the measurement noise.

Using Trial Vocal Fold Injection to Select Vocal Fold Scar Patients Who May Benefit From More Durable Augmentation.

PubMed

Carroll, Thomas L; Dezube, Aaron; Bauman, Laura A; Mallur, Pavan S

2018-02-01

Clinical indications for vocal fold injection augmentation (VFI) are expanding. Prior studies demonstrate the benefit of trial VFI for select causes of glottic insufficiency. No studies have examined trial VFI for glottic insufficiency resulting from true vocal fold (TVF) scar. Retrospective chart review of patients who underwent trial VFI for a dominant pathology of TVF scar causing dysphonia. Patients who subsequently underwent durable augmentation were identified. The primary study outcome was the difference in Voice Handicap Index-10 (VHI-10) score from pretrial VFI to post-durable augmentation. Twenty-eight patients underwent trial VFI for TVF scar, 22 of whom reported a positive response. Fifteen of 22 subjects who underwent durable augmentation had viable data for analysis. Mean VHI-10 improved from 26.9 to 18.6 ( P < .05), for a delta VHI-10 of 8.3, or 30.9% improvement. Twelve of the 15 (80%) showed a clinically significant improvement (delta VHI-10 >5). A trial VFI is a potentially useful, low-risk procedure that appears to help the patient and clinician identify when global augmentation might improve the voice when vocal fold scar is present. Patients who reported successful trial VFI often demonstrated significant improvement in their VHI-10 after subsequent durable augmentation.

Labor progress indices and dynamics of the individual uterine contraction during the active stage of labor.

PubMed

Ophir, Ella; Bornstein, Jacob; Odeh, Marwan; Kaminsky, Svetlana; Shnaider, Oleg; Megel, Yuri; Barnea, Ofer

2014-03-01

To obtain and study new data on the dynamics of the labor process and to develop a contraction-based index of labor progress. This study was carried out at the Delivery Room, Department of Obstetrics and Gynecology, Western Galilee Hospital, Nahariya, Israel, using a new device (Birth Track). We continuously monitored cervical dilatation (CD) and head descent (HD) in 30 nulliparaous women during active labor with (augmented group) and without (study group) oxytocin augmentation. This led to the development and validation of progress indices based on features extracted from continuous monitoring. There were no significant differences between the average of each parameter in the study and augmented groups, except for HD velocity. Average HD velocity was faster in the study group. Linear regression analyses demonstrated that head station (HS) amplitude and Toco amplitude were the best parameters for predicting HD velocity in both groups. In the study group, average HD velocity was also significantly related to Toco rate and contraction efficiency. In the augmented group, only a weak correlation with Toco rate was seen, and no correlation with contraction efficiency. With the assistance of the Birth Track device, we can obtain continuous data on the labor process and indices to estimate the labor progress process without the use of vaginal (manual) examination. © 2013 The Authors. Journal of Obstetrics and Gynaecology Research © 2013 Japan Society of Obstetrics and Gynecology.

Development of an IOS App Using Situated Learning, Communities of Practice, and Augmented Reality for Autism Spectrum Disorder

ERIC Educational Resources Information Center

Clarkson, Jessica

2014-01-01

This paper presents the development process and framework used to construct a transportation app that uses situated learning, augmented reality, and communities of practice. Autism spectrum disorder (ASD) is a neurodevelopmental disorder that can cause social impairments as well as the limit the potential for the individual to achieve independence…

Contextualized Interdisciplinary Learning in Mainstream Schools Using Augmented Reality-Based Technology: A Dream or Reality?

ERIC Educational Resources Information Center

Ong, Alex

2010-01-01

The use of augmented reality (AR) tools, where virtual objects such as tables and graphs can be displayed and be interacted with in real scenes created from imaging devices, in mainstream school curriculum is uncommon, as they are potentially costly and sometimes bulky. Thus, such learning tools are mainly applied in tertiary institutions, such as…

Augmented Reality M-Learning to Enhance Nursing Skills Acquisition in the Clinical Skills Laboratory

ERIC Educational Resources Information Center

Garrett, Bernard M.; Jackson, Cathryn; Wilson, Brian

2015-01-01

Purpose: This paper aims to report on a pilot research project designed to explore if new mobile augmented reality (AR) technologies have the potential to enhance the learning of clinical skills in the lab. Design/methodology/approach: An exploratory action-research-based pilot study was undertaken to explore an initial proof-of-concept design in…

Augmented Reality and Mobile Learning: The State of the Art

ERIC Educational Resources Information Center

FitzGerald, Elizabeth; Ferguson, Rebecca; Adams, Anne; Gaved, Mark; Mor, Yishay; Thomas, Rhodri

2013-01-01

In this paper, the authors examine the state of the art in augmented reality (AR) for mobile learning. Previous work in the field of mobile learning has included AR as a component of a wider toolkit but little has been done to discuss the phenomenon in detail or to examine in a balanced fashion its potential for learning, identifying both positive…

Pokémon-Go: Why Augmented Reality Games Offer Insights for Enhancing Public Health Interventions on Obesity-Related Diseases.

PubMed

Wong, Ming Chao; Turner, Paul; MacIntyre, Kate; Yee, Kwang Chien

2017-01-01

Stimulating widespread interests of the population to participate in behavioural changes through information and technology has been an aim of much health informatics research. The recent widespread participation of the augmented reality game Pokémon Go which encourages exercises, provides significant insights into the potential of information technology to improve healthcare intervention on obesity-related disease. Does Pokémon Go point to another way of achieving health benefits using mobile devices? This paper analyses the features of Pokémon Go in relation to potential health benefits. This paper suggests from the perspective of a user on changes to the game that potentially could help with obesity, mental health cardiovascular health and vitamin D deficiencies. While the impact of augmented reality games on improving exercises might be substantial, the question of sustainability and likely long-term health outcomes remain debatable. The rapid uptake of Pokémon Go by the population around the world, however, should serve as a useful lesson for information and technological design to improve outcomes obesity-related diseases in the future.

Frontal auditory evoked potentials and augmenting-reducing.

PubMed

Bruneau, N; Roux, S; Garreau, B; Lelord, G

1985-09-01

Auditory evoked potentials (AEPs) to tones (750 Hz--200 msec) ranging from 50 to 80 dB SPL were studied at Cz and Fz leads in 29 normal adults (15 males) ranging in age from 20 to 22. Peak-to-trough amplitudes were measured for the P1-N1 and the N1-P2 wave forms as well as baseline (500 msec prestimulus)-to-peak amplitudes for each component, i.e., P1, N1 and P2. Amplitudes were examined as a function of intensity and electrode location. Cz-Fz amplitude differences increased with increasing stimulus intensity, the differentiating peak being the N1 component. An overall reducing phenomenon was found at Fz in the 70-80 dB range whereas an augmenting effect was observed at Cz for these intensities. The augmenting/reducing groups defined by analysis of individual amplitude-intensity patterns were different whether we considered Fz or Cz results: Fz reducers were more numerous than Cz reducers. These results on prominent reducing at the frontal level were examined in relation to the data concerning the modulatory function of the frontal cortex on auditory EPs. Implications were drawn for the role of the frontal cortex in cortical augmenting-reducing.

Iterative methods for mixed finite element equations

NASA Technical Reports Server (NTRS)

Nakazawa, S.; Nagtegaal, J. C.; Zienkiewicz, O. C.

1985-01-01

Iterative strategies for the solution of indefinite system of equations arising from the mixed finite element method are investigated in this paper with application to linear and nonlinear problems in solid and structural mechanics. The augmented Hu-Washizu form is derived, which is then utilized to construct a family of iterative algorithms using the displacement method as the preconditioner. Two types of iterative algorithms are implemented. Those are: constant metric iterations which does not involve the update of preconditioner; variable metric iterations, in which the inverse of the preconditioning matrix is updated. A series of numerical experiments is conducted to evaluate the numerical performance with application to linear and nonlinear model problems.

High sensitivity of positrons to oxygen vacancies and to copper-oxygen chain disorder in YBa2Cu3O(7-x)

NASA Astrophysics Data System (ADS)

von Stetten, E. C.; Berko, S.; Li, X. S.; Lee, R. R.; Brynestad, J.

1988-05-01

Temperature-dependent positron-electron momentum densities have been studied by two-dimensional angular correlation of annihilation radiation from 10 to 320 K in YBa2Cu3O(7-x) samples. The positron ground-state charge density, computed by the linearized augmented-plane-wave method, indicates that in YBa2Cu3O7 delocalized positrons sample preferentially the linear copper-oxygen chains. Positron localization due to disorder in these chains is invoked to explain the striking differences observed between superconducting (x = about 0.02) and nonsuperconducting (x = about 0.70) samples.

Nonlinear graphene plasmonics

PubMed Central

2017-01-01

The rapid development of graphene has opened up exciting new fields in graphene plasmonics and nonlinear optics. Graphene's unique two-dimensional band structure provides extraordinary linear and nonlinear optical properties, which have led to extreme optical confinement in graphene plasmonics and ultrahigh nonlinear optical coefficients, respectively. The synergy between graphene's linear and nonlinear optical properties gave rise to nonlinear graphene plasmonics, which greatly augments graphene-based nonlinear device performance beyond a billion-fold. This nascent field of research will eventually find far-reaching revolutionary technological applications that require device miniaturization, low power consumption and a broad range of operating wavelengths approaching the far-infrared, such as optical computing, medical instrumentation and security applications. PMID:29118665

Nonlinear graphene plasmonics

NASA Astrophysics Data System (ADS)

Ooi, Kelvin J. A.; Tan, Dawn T. H.

2017-10-01

The rapid development of graphene has opened up exciting new fields in graphene plasmonics and nonlinear optics. Graphene's unique two-dimensional band structure provides extraordinary linear and nonlinear optical properties, which have led to extreme optical confinement in graphene plasmonics and ultrahigh nonlinear optical coefficients, respectively. The synergy between graphene's linear and nonlinear optical properties gave rise to nonlinear graphene plasmonics, which greatly augments graphene-based nonlinear device performance beyond a billion-fold. This nascent field of research will eventually find far-reaching revolutionary technological applications that require device miniaturization, low power consumption and a broad range of operating wavelengths approaching the far-infrared, such as optical computing, medical instrumentation and security applications.

Smart maintenance of riverbanks using a standard data layer and Augmented Reality

NASA Astrophysics Data System (ADS)

Pierdicca, Roberto; Frontoni, Emanuele; Zingaretti, Primo; Mancini, Adriano; Malinverni, Eva Savina; Tassetti, Anna Nora; Marcheggiani, Ernesto; Galli, Andrea

2016-10-01

Linear buffer strips (BS) along watercourses are commonly adopted to reduce run-off, accumulation of bank-top sediments and the leaking of pesticides into fresh-waters, which strongly increase water pollution. However, the monitoring of their conditions is a difficult task because they are scattered over wide rural areas. This work demonstrates the benefits of using a standard data layer and Augmented Reality (AR) in watershed control and outlines the guideline of a novel approach for the health-check of linear BS. We designed a mobile environmental monitoring system for smart maintenance of riverbanks by embedding the AR technology within a Geographical Information System (GIS). From the technological point of view, the system's architecture consists of a cloud-based service for data sharing, using a standard data layer, and of a mobile device provided with a GPS based AR engine for augmented data visualization. The proposed solution aims to ease the overall inspection process by reducing the time required to run a survey. Indeed, ordinary operational survey conditions are usually performed basing the fieldwork on just classical digitized maps. Our application proposes to enrich inspections by superimposing information on the device screen with the same point of view of the camera, providing an intuitive visualization of buffer strip location. This way, the inspection officer can quickly and dynamically access relevant information overlaying geographic features, comments and other contents in real time. The solution has been tested in fieldwork to prove at what extent this cutting-edge technology contributes to an effective monitoring over large territorial settings. The aim is to encourage officers, land managers and practitioners toward more effective monitoring and management practices.

Computerised mirror therapy with Augmented Reflection Technology for early stroke rehabilitation: clinical feasibility and integration as an adjunct therapy.

PubMed

Hoermann, Simon; Ferreira Dos Santos, Luara; Morkisch, Nadine; Jettkowski, Katrin; Sillis, Moran; Devan, Hemakumar; Kanagasabai, Parimala S; Schmidt, Henning; Krüger, Jörg; Dohle, Christian; Regenbrecht, Holger; Hale, Leigh; Cutfield, Nicholas J

2017-07-01

New rehabilitation strategies for post-stroke upper limb rehabilitation employing visual stimulation show promising results, however, cost-efficient and clinically feasible ways to provide these interventions are still lacking. An integral step is to translate recent technological advances, such as in virtual and augmented reality, into therapeutic practice to improve outcomes for patients. This requires research on the adaptation of the technology for clinical use as well as on the appropriate guidelines and protocols for sustainable integration into therapeutic routines. Here, we present and evaluate a novel and affordable augmented reality system (Augmented Reflection Technology, ART) in combination with a validated mirror therapy protocol for upper limb rehabilitation after stroke. We evaluated components of the therapeutic intervention, from the patients' and the therapists' points of view in a clinical feasibility study at a rehabilitation centre. We also assessed the integration of ART as an adjunct therapy for the clinical rehabilitation of subacute patients at two different hospitals. The results showed that the combination and application of the Berlin Protocol for Mirror Therapy together with ART was feasible for clinical use. This combination was integrated into the therapeutic plan of subacute stroke patients at the two clinical locations where the second part of this research was conducted. Our findings pave the way for using technology to provide mirror therapy in clinical settings and show potential for the more effective use of inpatient time and enhanced recoveries for patients. Implications for Rehabilitation Computerised Mirror Therapy is feasible for clinical use Augmented Reflection Technology can be integrated as an adjunctive therapeutic intervention for subacute stroke patients in an inpatient setting Virtual Rehabilitation devices such as Augmented Reflection Technology have considerable potential to enhance stroke rehabilitation.

Binary Classification of an Unknown Object through Atmospheric Turbulence Using a Polarimetric Blind-Deconvolution Algorithm Augmented with Adaptive Degree of Linear Polarization Priors

DTIC Science & Technology

2012-03-01

geometry of reflection from a smooth (or mirror-like) surface [27]. In passive polarimetry , the angle of polarization (AoP) provides information about... polarimetry for remote sens- ing applications”. Appl. Opt., 45(22):5453–5469, Aug 2006. URL http://ao.osa.org/abstract.cfm?URI=ao-45-22-5453. 27

Real-time prediction of respiratory motion based on a local dynamic model in an augmented space

NASA Astrophysics Data System (ADS)

Hong, S.-M.; Jung, B.-H.; Ruan, D.

2011-03-01

Motion-adaptive radiotherapy aims to deliver ablative radiation dose to the tumor target with minimal normal tissue exposure, by accounting for real-time target movement. In practice, prediction is usually necessary to compensate for system latency induced by measurement, communication and control. This work focuses on predicting respiratory motion, which is most dominant for thoracic and abdominal tumors. We develop and investigate the use of a local dynamic model in an augmented space, motivated by the observation that respiratory movement exhibits a locally circular pattern in a plane augmented with a delayed axis. By including the angular velocity as part of the system state, the proposed dynamic model effectively captures the natural evolution of respiratory motion. The first-order extended Kalman filter is used to propagate and update the state estimate. The target location is predicted by evaluating the local dynamic model equations at the required prediction length. This method is complementary to existing work in that (1) the local circular motion model characterizes 'turning', overcoming the limitation of linear motion models; (2) it uses a natural state representation including the local angular velocity and updates the state estimate systematically, offering explicit physical interpretations; (3) it relies on a parametric model and is much less data-satiate than the typical adaptive semiparametric or nonparametric method. We tested the performance of the proposed method with ten RPM traces, using the normalized root mean squared difference between the predicted value and the retrospective observation as the error metric. Its performance was compared with predictors based on the linear model, the interacting multiple linear models and the kernel density estimator for various combinations of prediction lengths and observation rates. The local dynamic model based approach provides the best performance for short to medium prediction lengths under relatively low observation rate. Sensitivity analysis indicates its robustness toward the choice of parameters. Its simplicity, robustness and low computation cost makes the proposed local dynamic model an attractive tool for real-time prediction with system latencies below 0.4 s.

Real-time prediction of respiratory motion based on a local dynamic model in an augmented space.

PubMed

Hong, S-M; Jung, B-H; Ruan, D

2011-03-21

Motion-adaptive radiotherapy aims to deliver ablative radiation dose to the tumor target with minimal normal tissue exposure, by accounting for real-time target movement. In practice, prediction is usually necessary to compensate for system latency induced by measurement, communication and control. This work focuses on predicting respiratory motion, which is most dominant for thoracic and abdominal tumors. We develop and investigate the use of a local dynamic model in an augmented space, motivated by the observation that respiratory movement exhibits a locally circular pattern in a plane augmented with a delayed axis. By including the angular velocity as part of the system state, the proposed dynamic model effectively captures the natural evolution of respiratory motion. The first-order extended Kalman filter is used to propagate and update the state estimate. The target location is predicted by evaluating the local dynamic model equations at the required prediction length. This method is complementary to existing work in that (1) the local circular motion model characterizes 'turning', overcoming the limitation of linear motion models; (2) it uses a natural state representation including the local angular velocity and updates the state estimate systematically, offering explicit physical interpretations; (3) it relies on a parametric model and is much less data-satiate than the typical adaptive semiparametric or nonparametric method. We tested the performance of the proposed method with ten RPM traces, using the normalized root mean squared difference between the predicted value and the retrospective observation as the error metric. Its performance was compared with predictors based on the linear model, the interacting multiple linear models and the kernel density estimator for various combinations of prediction lengths and observation rates. The local dynamic model based approach provides the best performance for short to medium prediction lengths under relatively low observation rate. Sensitivity analysis indicates its robustness toward the choice of parameters. Its simplicity, robustness and low computation cost makes the proposed local dynamic model an attractive tool for real-time prediction with system latencies below 0.4 s.

Electronic structure and defect properties of selenophosphate Pb2P2Se6 for γ-ray detection

NASA Astrophysics Data System (ADS)

Kontsevoi, Oleg Y.; Im, Jino; Wessels, Bruce W.; Kanatzidis, Mercouri G.; Freeman, Arthur J.

Heavy metal chalco-phosphate Pb2P2Se6 has shown a significant promise as an X-ray and γ-ray detector material. To assess the fundamental physical properties important for its performance as detector, theoretical calculations were performed for the electronic structure, band gaps, electron and hole effective masses, and static dielectric constants. The calculations were based on first-principles density functional theory (DFT) and employ the highly precise full potential linearized augmented plane wave method and the projector augmented wave method and include nonlocal exchange-correlation functionals to overcome the band gap underestimation in DFT calculations. The calculations show that Pb2P2Se6 is an indirect band gap material with the calculated band gap of 2.0 eV, has small effective masses, which could result in a good carrier mobility-lifetime product μτ , and a very high static dielectric constant, which could lead to high mobility of carriers by screening of charged scattering centers. We further investigated a large set of native defects in Pb2P2Se6 to determine the optimal growth conditions for application as γ-ray detectors. The results suggest that the prevalent intrinsic defects are selenium vacancies, followed by lead vacancies, then phosphorus vacancies and antisite defects. The effect of various chemical environments on defect properties was examined and the optimal conditions for material synthesis were suggested. Supported by DHS (Grant No. 2014-DN-077-ARI086-01).

Identification and treatment of augmentation in patients with restless legs syndrome: practical recommendations.

PubMed

Geyer, James; Bogan, Richard

2017-09-01

Restless legs syndrome (RLS) is a chronic disorder causing clinically significant discomfort to approximately 3% of adults. Although RLS was first identified centuries ago, our understanding of this disorder, its causes, and its treatments is still evolving. In particular, our knowledge of the potential negative effects of RLS treatments, including dopaminergic augmentation, continues to expand. Augmentation, which refers to a paradoxical treatment-related increase in RLS symptoms, has been associated with all three dopamine agonists approved for the treatment of RLS - rotigotine, pramipexole, and ropinirole. This review presents key information on prevention and treatment of dopaminergic augmentation from the recently published consensus-based guidelines issued by the International RLS Study Group task force in conjunction with the European RLS Study Group and the RLS Foundation for first-line treatment of RLS/Willis-Ekbom disease. If dopamine agonists are used to treat RLS, it is recommended that the dosage should be kept as low as possible without exceeding the maximum dose recommended for RLS treatment. As the frequency of augmentation with the rotigotine patch may only be slightly lower than that associated with pramipexole or ropinirole, medications that are effective and have little risk of augmentation, such as alpha-2-delta ligands, may be considered for initial RLS treatment. In addition, we present our clinical experience with treating patients with dopaminergic augmentation by highlighting 2 case studies and practical considerations when treating different patient populations. Applying current RLS augmentation diagnosis and treatment guidelines, as well as collecting detailed histories of worsening RLS symptoms, is critical for patient safety and effective management of RLS augmentation.

Mechanical and magneto-opto-electronic investigation of transition metal based fluoro-perovskites: An ab-initio DFT study

NASA Astrophysics Data System (ADS)

Erum, Nazia; Azhar Iqbal, Muhammad

2017-09-01

Detailed ab-initio calculations are performed to investigate structural, elastic, mechanical, magneto-electronic and optical properties of the KXF3 (X = V, Fe, Co, Ni) fluoro-perovskites using Full Potential Linearized Augmented Plane Wave (FP-LAPW) method within the framework of density functional theory (DFT). The calculated structural parameters by DFT and analytical methods are found consistent with the experimental results. From the elastic and mechanical properties, it can be inferred that these compounds are elastically stable and anisotropic while KCoF3 is harder than rest of the compounds. Furthermore, thermal behavior of these compounds is analyzed by calculating Debye temperature (θD). The calculated spin dependent magneto-electronic properties in these compounds reveal that exchange splitting is dominated by N-3d orbital. The stable magnetic phase optimizations verify the experimental observations at low temperature. Type of chemical bonding is analyzed with the help of variations in electron density difference distribution that is induced due to changes of the second cation. The linear optical properties are also discussed in terms of optical spectra. The present methodology represents an influential approach to calculate the whole set of mechanical and magneto-opto-electronic parameters, which would support to understand various physical phenomena and empower device engineers for implementing these materials in spintronic applications.

Two-photon momentum density in La2-xSrxCuO4 and Nd2-xCexCuO4

NASA Astrophysics Data System (ADS)

Blandin, P.; Massidda, S.; Barbiellini, B.; Jarlborg, T.; Lerch, P.; Manuel, A. A.; Hoffmann, L.; Gauthier, M.; Sadowski, W.; Walker, E.; Peter, M.; Yu, Jaejun; Freeman, A. J.

1992-07-01

We present calculations of the electron-positron momentum density for the high-Tc superconductors La2-xSrxCuO4 and Nd2-xCexCuO4, together with experimental two-dimensional angular correlation of annihilation radiation (2D-ACAR) for Nd2-xCexCuO4. The calculations are based on first-principles electronic structure obtained using the full-potential linearized augmented-plane-wave and the linear muffin-tin orbital methods. Our results indicate a non-negligible overlap of the positron wave function with the CuO2 plane electrons responsible for the Fermi surfaces in these compounds. Therefore, these compounds may be well suited for investigating Fermi-surface-related effects. After the folding of umklapp terms according to Lock, Crisp, and West, the predicted Fermi-surface breaks are mixed with strong effects induced by the positron wave function in La2-xSrxCuO4, while their resolution is better in Nd2-xCexCuO4. A comparison of our calculations with the most recent experimental results for La2-xSrxCuO4 shows good agreement. For Nd2-xCexCuO4 good agreement is observed between theoretical and experimental 2D-ACAR profiles.

Different brain activity in response to emotional faces alone and augmented by contextual information.

PubMed

Lee, Kyung Hwa; Siegle, Greg J

2014-11-01

This study examined the extent to which emotional face stimuli differ from the neural reactivity associated with more ecological contextually augmented stimuli. Participants were scanned when they viewed contextually rich pictures depicting both emotional faces and context, and pictures of emotional faces presented alone. Emotional faces alone were more strongly associated with brain activity in paralimbic and social information processing regions, whereas emotional faces augmented by context were associated with increased and sustained activity in regions potentially representing increased complexity and subjective emotional experience. Furthermore, context effects were modulated by emotional intensity and valence. These findings suggest that cortical elaboration that is apparent in contextually augmented stimuli may be missed in studies of emotional faces alone, whereas emotional faces may more selectively recruit limbic reactivity. Copyright © 2014 Society for Psychophysiological Research.

The locus of origin of augmenting and reducing of visual evoked potentials in rat brain.

PubMed

Siegel, J; Gayle, D; Sharma, A; Driscoll, P

1996-07-01

Humans who are high sensation seekers and cats who demonstrate comparable behavioral traits show increasing amplitudes of the early components of the cortical visual evoked potential (VEP) to increasing intensities of light flash; low sensation seekers show VEP reducing. Roman high-avoidance (RHA) and Roman low-avoidance (RLA) rats have behavioral traits comparable to human and cat high and low sensation seekers, respectively. Previously, we showed that RHA and RLA rats are cortical VEP augmenters and reducers, respectively. The goal of this study was to determine if augmenting-reducing is in fact a property of the visual cortex or if it originates at the lateral geniculate nucleus and is merely reflected in recordings from the cortex. EPs to five flash intensities were recorded from the visual cortex and dorsal lateral geniculate of RHA and RLA rats. As in the previous study, the slope of the first cortical component as a function of flash intensity was greater in the RHA than in the RLA rats. The amplitude of the geniculate component that has a latency shorter than the first cortical component was no different in the two lines of rats. The finding from the cortex confirms the earlier finding of augmenting and reducing in RHA and RLA rats, respectively. The major new finding is that the augmenting-reducing difference recorded at the cortex does not occur at the thalamus, indicating that it is truly a cortical phenomenon.

A new orthosis reduces pain and mechanical forces in prone position in women with augmented or natural breast tissue: a pilot study.

PubMed

Armstrong, Simon; Ried, Karin; Sali, Avni; McLaughlin, Patrick

2013-07-01

Breast augmentation, post-mastectomy patients as well as some women with natural breast tissue, and lactating, women often experience discomfort in prone activities. Our study, for the first time, examines pain levels, mechanical force and peak pressure in natural, reconstructed and augmented breast tissues with and without a new orthosis designed for reduction of displacement, compression and loading forces through the breast tissue during prone activities. Twelve females with natural, lactating or augmented breast tissue, and cup-sizes C-F volunteered for the study. Pain perception was measured using an 11-point visual-analogue-scale without and with different sizes/textures of the orthosis. Magnetic-Resonance-Imaging captured segmental transverse and para-sagittal mid-breast views, and provided linear measurements of breast tissue displacement and deformation. Capacitance-pliance® sensorstrips were used to measure force and pressure between the breast tissue and the surface of a standard treatment table. Measurements were taken whilst the participants were load bearing in prone positions with and without the orthosis. The new orthosis significantly reduced pain and mechanical forces in participants with natural or augmented breast tissue with cup-sizes C-F. Larger orthotic sizes were correlated with greater reduction in pain and mechanical forces, with all participants reporting no pain with the largest size orthotic. A size-3 orthotic decreased load on the breast tissue by 82% and reduced peak pressure by 42%. The same orthotic decreased medio-lateral spread of breast tissue and implant whilst increasing height. The new orthosis significantly reduced pain and mechanical forces in all women with natural or augmented tissues. Results are of clinical significance, as reduced mechanical forces are associated with greater comfort and reduced pressure and displacement which may lower the probability of breast implant complication. In clinical settings the orthosis is recommended for all augmentation patients when undergoing prone treatment by therapists and clinicians for improved comfort and safety. Copyright © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Potential risks of using cement-augmented screws for spinal fusion in patients with low bone quality.

PubMed

Martín-Fernández, M; López-Herradón, A; Piñera, A R; Tomé-Bermejo, F; Duart, J M; Vlad, M D; Rodríguez-Arguisjuela, M G; Alvarez-Galovich, L

2017-08-01

Dramatic increases in the average life expectancy have led to increases in the variety of degenerative changes and deformities observed in the aging spine. The elderly population can present challenges for spine surgeons, not only because of increased comorbidities, but also because of the quality of their bones. Pedicle screws are the implants used most commonly in spinal surgery for fixation, but their efficacy depends directly on bone quality. Although polymethyl methacrylate (PMMA)-augmented screws represent an alternative for patients with osteoporotic vertebrae, their use has raised some concerns because of the possible association between cement leakages (CLs) and other morbidities. To analyze potential complications related to the use of cement-augmented screws for spinal fusion and to investigate the effectiveness of using these screws in the treatment of patients with low bone quality. A retrospective single-center study. This study included 313 consecutive patients who underwent spinal fusion using a total of 1,780 cement-augmented screws. We analyzed potential complications related to the use of cement-augmented screws, including CL, vascular injury, infection, screw extraction problems, revision surgery, and instrument failure. There are no financial conflicts of interest to report. A total of 1,043 vertebrae were instrumented. Cement leakage was observed in 650 vertebrae (62.3%). There were no major clinical complications related to CL, but two patients (0.6%) had radicular pain related to CL at the S1 foramina. Of the 13 patients (4.1%) who developed deep infections requiring surgical debridement, two with chronic infections had possible spondylitis that required instrument removal. All patients responded well to antibiotic therapy. Revision surgery was performed in 56 patients (17.9%), most of whom had long construction. A total of 180 screws were removed as a result of revision. There were no problems with screw extraction. These results demonstrate the efficacy and safety of cement-augmented screws for the treatment of patients with low bone mineral density. Copyright © 2017 Elsevier Inc. All rights reserved.

A new ab initio potential energy surface for the collisional excitation of HCN by para- and ortho-H2

NASA Astrophysics Data System (ADS)

Denis-Alpizar, Otoniel; Kalugina, Yulia; Stoecklin, Thierry; Vera, Mario Hernández; Lique, François

2013-12-01

We present a new four-dimensional potential energy surface for the collisional excitation of HCN by H2. Ab initio calculations of the HCN-H2 van der Waals complex, considering both molecules as rigid rotors, were carried out at the explicitly correlated coupled cluster with single, double, and perturbative triple excitations [CCSD(T)-F12a] level of theory using an augmented correlation-consistent triple zeta (aVTZ) basis set. The equilibrium structure is linear HCN-H2 with the nitrogen pointing towards H2 at an intermolecular separation of 7.20 a0. The corresponding well depth is -195.20 cm-1. A secondary minimum of -183.59 cm-1 was found for a T-shape configuration with the H of HCN pointing to the center of mass of H2. We also determine the rovibrational energy levels of the HCN-para-H2 and HCN-ortho-H2 complexes. The calculated dissociation energies for the para and ortho complexes are 37.79 cm-1 and 60.26 cm-1, respectively. The calculated ro-vibrational transitions in the HCN-H2 complex are found to agree by more than 0.5% with the available experimental data, confirming the accuracy of the potential energy surface.

Revealing the optoelectronic and thermoelectric properties of the Zintl quaternary arsenides ACdGeAs{sub 2} (A = K, Rb)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Azam, Sikander; Khan, Saleem Ayaz; Goumri-Said, Souraya, E-mail: Souraya.Goumri-Said@chemistry.gatech.edu

Highlights: • Zintl tetragonal phase ACdGeAs{sub 2} (A = K, Rb) are chalcopyrite and semiconductors. • Their direct band gap is suitable for PV, optolectronic and thermoelectric applications. • Combination of DFT and Boltzmann transport theory is employed. • The present arsenides are found to be covalent materials. - Abstract: Chalcopyrite semiconductors have attracted much attention due to their potential implications in photovoltaic and thermoelectric applications. First principle calculations were performed to investigate the electronic, optical and thermoelectric properties of the Zintl tetragonal phase ACdGeAs{sub 2} (A = K, Rb) using the full potential linear augmented plane wave method andmore » the Engle–Vosko GGA (EV–GGA) approximation. The present compounds are found semiconductors with direct band gap and covalent bonding character. The optical transitions are investigated via the dielectric function (real and imaginary parts) along with other related optical constants including refractive index, reflectivity and energy-loss spectrum. Combining results from DFT and Boltzmann transport theory, we reported the thermoelectric properties such as the Seebeck’s coefficient, electrical and thermal conductivity, figure of merit and power factor as function of temperatures. The present chalcopyrite Zintl quaternary arsenides deserve to be explored for their potential applications as thermoelectric materials and for photovoltaic devices.« less

Theoretical investigation of the structural stabilities, optoelectronic properties and thermodynamic characteristics of GaPxSb1-x ternary alloys

NASA Astrophysics Data System (ADS)

Oumelaz, F.; Nemiri, O.; Boumaza, A.; Ghemid, S.; Meradji, H.; Bin Omran, S.; El Haj Hassan, F.; Rai, D. P.; Khenata, R.

2018-06-01

In this theoretical study, we have investigated the structural, phase transition, electronic, thermodynamic and optical properties of GaPxSb1-x ternary alloys. Our calculations are performed with the WIEN2k code based on density functional theory using the full-potential linearized augmented plane wave method. For the electron exchange-correlation potential, a generalized gradient approximation within Wu-Cohen scheme is considered. The recently developed Tran-Blaha modified Becke-Johnson potential has also been used to improve the underestimated band gap. The structural properties, including the lattice constants, the bulk moduli and their pressure derivatives are in very good agreement with the available experimental data and theoretical results. Several structural phase transitions were studied here to establish the stable structure and to predict the phase transition under hydrostatic pressure. The computed transition pressure (Pt) of the material of our interest from the zinc blende (B3) to the rock salt (B1) phase has been determined and found to agree well with the experimental and theoretical data. The calculated band structure shows that GaSb binary compound and the ternary alloys are direct band gap semiconductors. Optical parameters such as the dielectric constants and the refractive indices are calculated and analyzed. The thermodynamic results are also interpreted and analyzed.

2D non-separable linear canonical transform (2D-NS-LCT) based cryptography

NASA Astrophysics Data System (ADS)

Zhao, Liang; Muniraj, Inbarasan; Healy, John J.; Malallah, Ra'ed; Cui, Xiao-Guang; Ryle, James P.; Sheridan, John T.

2017-05-01

The 2D non-separable linear canonical transform (2D-NS-LCT) can describe a variety of paraxial optical systems. Digital algorithms to numerically evaluate the 2D-NS-LCTs are not only important in modeling the light field propagations but also of interest in various signal processing based applications, for instance optical encryption. Therefore, in this paper, for the first time, a 2D-NS-LCT based optical Double-random- Phase-Encryption (DRPE) system is proposed which offers encrypting information in multiple degrees of freedom. Compared with the traditional systems, i.e. (i) Fourier transform (FT); (ii) Fresnel transform (FST); (iii) Fractional Fourier transform (FRT); and (iv) Linear Canonical transform (LCT), based DRPE systems, the proposed system is more secure and robust as it encrypts the data with more degrees of freedom with an augmented key-space.

In-Flight Suppression of an Unstable F/A-18 Structural Mode Using the Space Launch System Adaptive Augmenting Control System

NASA Technical Reports Server (NTRS)

VanZwieten, Tannen S.; Gilligan, Eric T.; Wall, John H.; Miller, Christopher J.; Hanson, Curtis E.; Orr, Jeb S.

2015-01-01

NASA's Space Launch System (SLS) Flight Control System (FCS) includes an Adaptive Augmenting Control (AAC) component which employs a multiplicative gain update law to enhance the performance and robustness of the baseline control system for extreme off-nominal scenarios. The SLS FCS algorithm including AAC has been flight tested utilizing a specially outfitted F/A-18 fighter jet in which the pitch axis control of the aircraft was performed by a Non-linear Dynamic Inversion (NDI) controller, SLS reference models, and the SLS flight software prototype. This paper describes test cases from the research flight campaign in which the fundamental F/A-18 airframe structural mode was identified using post-flight frequency-domain reconstruction, amplified to result in closed loop instability, and suppressed in-flight by the SLS adaptive control system.

An Augmented Lagrangian Filter Method for Real-Time Embedded Optimization

DOE PAGES

Chiang, Nai -Yuan; Huang, Rui; Zavala, Victor M.

2017-04-17

We present a filter line-search algorithm for nonconvex continuous optimization that combines an augmented Lagrangian function and a constraint violation metric to accept and reject steps. The approach is motivated by real-time optimization applications that need to be executed on embedded computing platforms with limited memory and processor speeds. The proposed method enables primal–dual regularization of the linear algebra system that in turn permits the use of solution strategies with lower computing overheads. We prove that the proposed algorithm is globally convergent and we demonstrate the developments using a nonconvex real-time optimization application for a building heating, ventilation, and airmore » conditioning system. Our numerical tests are performed on a standard processor and on an embedded platform. Lastly, we demonstrate that the approach reduces solution times by a factor of over 1000.« less

An Augmented Lagrangian Filter Method for Real-Time Embedded Optimization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chiang, Nai -Yuan; Huang, Rui; Zavala, Victor M.

We present a filter line-search algorithm for nonconvex continuous optimization that combines an augmented Lagrangian function and a constraint violation metric to accept and reject steps. The approach is motivated by real-time optimization applications that need to be executed on embedded computing platforms with limited memory and processor speeds. The proposed method enables primal–dual regularization of the linear algebra system that in turn permits the use of solution strategies with lower computing overheads. We prove that the proposed algorithm is globally convergent and we demonstrate the developments using a nonconvex real-time optimization application for a building heating, ventilation, and airmore » conditioning system. Our numerical tests are performed on a standard processor and on an embedded platform. Lastly, we demonstrate that the approach reduces solution times by a factor of over 1000.« less

Analysis of the Westland Data Set

NASA Technical Reports Server (NTRS)

Wen, Fang; Willett, Peter; Deb, Somnath

2001-01-01

The "Westland" set of empirical accelerometer helicopter data with seeded and labeled faults is analyzed with the aim of condition monitoring. The autoregressive (AR) coefficients from a simple linear model encapsulate a great deal of information in a relatively few measurements; and it has also been found that augmentation of these by harmonic and other parameters call improve classification significantly. Several techniques have been explored, among these restricted Coulomb energy (RCE) networks, learning vector quantization (LVQ), Gaussian mixture classifiers and decision trees. A problem with these approaches, and in common with many classification paradigms, is that augmentation of the feature dimension can degrade classification ability. Thus, we also introduce the Bayesian data reduction algorithm (BDRA), which imposes a Dirichlet prior oil training data and is thus able to quantify probability of error in all exact manner, such that features may be discarded or coarsened appropriately.

Antiwindup analysis and design approaches for MIMO systems

NASA Technical Reports Server (NTRS)

Marcopoli, Vincent R.; Phillips, Stephen M.

1994-01-01

Performance degradation of multiple-input multiple-output (MIMO) control systems having limited actuators is often handled by augmenting the controller with an antiwindup mechanism, which attempts to maintain system performance when limits are encountered. The goals of this paper are: (1) To develop a method to analyze antiwindup systems to determine precisely what stability and performance degradation is incurred under limited conditions. It is shown that by reformulating limited actuator commands as resulting from multiplicative perturbations to the corresponding controller requests, mu-analysis tools can be utilized to obtain quantitative measures of stability and performance degradation. (2) To propose a linear, time invariant (LTI) criterion on which to base the antiwindup design. These analysis and design methods are illustrated through the evaluation of two competing antiwindup schemes augmenting the controller of a Short Take-Off and Vertical Landing (STOVL) aircraft in transition flight.

Antiwindup analysis and design approaches for MIMO systems

NASA Technical Reports Server (NTRS)

Marcopoli, Vincent R.; Phillips, Stephen M.

1993-01-01

Performance degradation of multiple-input multiple-output (MIMO) control systems having limited actuators is often handled by augmenting the controller with an antiwindup mechanism, which attempts to maintain system performance when limits are encountered. The goals of this paper are: 1) to develop a method to analyze antiwindup systems to determine precisely what stability and performance degradation is incurred under limited conditions. It is shown that by reformulating limited actuator commands as resulting from multiplicative perturbations to the corresponding controller requests, mu-analysis tools can be utilized to obtain quantitative measures of stability and performance degradation. 2) To propose a linear, time invariant (LTI) criterion on which to base the antiwindup design. These analysis and design methods are illustrated through the evaluation of two competing antiwindup schemes augmenting the controller of a Short Take-Off and Vertical Landing (STOVL) aircraft in transition flight.

Realizable optimal control for a remotely piloted research vehicle. [stability augmentation

NASA Technical Reports Server (NTRS)

Dunn, H. J.

1980-01-01

The design of a control system using the linear-quadratic regulator (LQR) control law theory for time invariant systems in conjunction with an incremental gradient procedure is presented. The incremental gradient technique reduces the full-state feedback controller design, generated by the LQR algorithm, to a realizable design. With a realizable controller, the feedback gains are based only on the available system outputs instead of being based on the full-state outputs. The design is for a remotely piloted research vehicle (RPRV) stability augmentation system. The design includes methods for accounting for noisy measurements, discrete controls with zero-order-hold outputs, and computational delay errors. Results from simulation studies of the response of the RPRV to a step in the elevator and frequency analysis techniques are included to illustrate these abnormalities and their influence on the controller design.

Electronic structure of Pt-substituted clathrate silicides Ba{sub 8}Pt{sub x}Si{sub 46–x}(x = 4–6)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borshch, N. A., E-mail: n.a.borshch@ya.ru

The results of calculation of the electronic structure of Si-based Pt-substituted clathrates are reported. Calculation is carried out by the linearized-augmented-plane-wave method. The effect of the number of substitutions and their crystallographic position in the unit cell on the electron-energy spectrum and the electronic properties of Pt-substituted clathrates is analyzed.

Active vibration damping of the Space Shuttle remote manipulator system

NASA Technical Reports Server (NTRS)

Scott, Michael A.; Gilbert, Michael G.; Demeo, Martha E.

1991-01-01

The feasibility of providing active damping augmentation of the Space Shuttle Remote Manipulator System (RMS) following normal payload handling operations is investigated. The approach used in the analysis is described, and the results for both linear and nonlinear performance analysis of candidate laws are presented, demonstrating that significant improvement in the RMS dynamic response can be achieved through active control using measured RMS tip acceleration data for feedback.

Challenges in computational evaluation of redox and magnetic properties of Fe-based sulfate cathode materials of Li- and Na-ion batteries

NASA Astrophysics Data System (ADS)

Shishkin, Maxim; Sato, Hirofumi

2017-06-01

Several Fe-based sulfates have been proposed recently as cathode materials characterized by a high average operating voltage (i.e. Li2Fe(SO4)2 and Na2Fe2(SO4)3) or low fabrication temperature (e.g. Na2Fe(SO4)2·2H2O)). In this work, we apply three methods to evaluate the redox potentials and magnetic properties of these materials: (1) local density functional theory (DFT) in Perdew-Burke-Ernzerhof parametrization; (2) rotationally invariant DFT  +  U and (3) DFT  +  U with magnetic exchange, suggested herein. The U parameters used for DFT  +  U calculations have been evaluated by using a linear response method (this applies to DFT  +  U as well as DFT  +  U calculations with a magnetic exchange term). Moreover, we have performed adjustments of U and, for the case of magnetic exchange, J parameters, to find better agreement with experimental measurements of redox and magnetic properties. We find that a self-consistent DFT  +  U/linear response approach yields quite overestimated redox potentials as compared to experiment. On the other hand, we also show that DFT  +  U calculations are not capable of providing a reasonably accurate description of both redox and magnetic properties for the case of Li2Fe(SO4)2, even when adjusted U parameters are employed. As a solution, we demonstrate that a DFT  +  U methodology augmented by a magnetic exchange term potentially provides more precise values for both the redox potentials and the magnetic moments of the Fe ions in the studied materials. Thus our work shows that for a more accurate description of redox and magnetic properties, further extensions of the DFT  +  U method, such as inclusion of the contribution of magnetic exchange, should be considered.

Augmented reality with image registration, vision correction and sunlight readability via liquid crystal devices.

PubMed

Wang, Yu-Jen; Chen, Po-Ju; Liang, Xiao; Lin, Yi-Hsin

2017-03-27

Augmented reality (AR), which use computer-aided projected information to augment our sense, has important impact on human life, especially for the elder people. However, there are three major challenges regarding the optical system in the AR system, which are registration, vision correction, and readability under strong ambient light. Here, we solve three challenges simultaneously for the first time using two liquid crystal (LC) lenses and polarizer-free attenuator integrated in optical-see-through AR system. One of the LC lens is used to electrically adjust the position of the projected virtual image which is so-called registration. The other LC lens with larger aperture and polarization independent characteristic is in charge of vision correction, such as myopia and presbyopia. The linearity of lens powers of two LC lenses is also discussed. The readability of virtual images under strong ambient light is solved by electrically switchable transmittance of the LC attenuator originating from light scattering and light absorption. The concept demonstrated in this paper could be further extended to other electro-optical devices as long as the devices exhibit the capability of phase modulations and amplitude modulations.

Sensor-Augmented Virtual Labs: Using Physical Interactions with Science Simulations to Promote Understanding of Gas Behavior

NASA Astrophysics Data System (ADS)

Chao, Jie; Chiu, Jennifer L.; DeJaegher, Crystal J.; Pan, Edward A.

2016-02-01

Deep learning of science involves integration of existing knowledge and normative science concepts. Past research demonstrates that combining physical and virtual labs sequentially or side by side can take advantage of the unique affordances each provides for helping students learn science concepts. However, providing simultaneously connected physical and virtual experiences has the potential to promote connections among ideas. This paper explores the effect of augmenting a virtual lab with physical controls on high school chemistry students' understanding of gas laws. We compared students using the augmented virtual lab to students using a similar sensor-based physical lab with teacher-led discussions. Results demonstrate that students in the augmented virtual lab condition made significant gains from pretest and posttest and outperformed traditional students on some but not all concepts. Results provide insight into incorporating mixed-reality technologies into authentic classroom settings.

Variational formulation for dissipative continua and an incremental J-integral

NASA Astrophysics Data System (ADS)

Rahaman, Md. Masiur; Dhas, Bensingh; Roy, D.; Reddy, J. N.

2018-01-01

Our aim is to rationally formulate a proper variational principle for dissipative (viscoplastic) solids in the presence of inertia forces. As a first step, a consistent linearization of the governing nonlinear partial differential equations (PDEs) is carried out. An additional set of complementary (adjoint) equations is then formed to recover an underlying variational structure for the augmented system of linearized balance laws. This makes it possible to introduce an incremental Lagrangian such that the linearized PDEs, including the complementary equations, become the Euler-Lagrange equations. Continuous groups of symmetries of the linearized PDEs are computed and an analysis is undertaken to identify the variational groups of symmetries of the linearized dissipative system. Application of Noether's theorem leads to the conservation laws (conserved currents) of motion corresponding to the variational symmetries. As a specific outcome, we exploit translational symmetries of the functional in the material space and recover, via Noether's theorem, an incremental J-integral for viscoplastic solids in the presence of inertia forces. Numerical demonstrations are provided through a two-dimensional plane strain numerical simulation of a compact tension specimen of annealed mild steel under dynamic loading.

Effects of an Augmented Reality-Based Educational Game on Students' Learning Achievements and Attitudes in Real-World Observations

ERIC Educational Resources Information Center

Hwang, Gwo-Jen; Wu, Po-Han; Chen, Chi-Chang; Tu, Nien-Ting

2016-01-01

Augmented reality (AR) has been recognized as a potential technology to help students link what they are observing in the real world to their prior knowledge. One of the most challenging issues of AR-based learning is the provision of effective strategy to help students focus on what they need to observe in the field. In this study, a competitive…

Control logic to track the outputs of a command generator or randomly forced target

NASA Technical Reports Server (NTRS)

Trankle, T. L.; Bryson, A. E., Jr.

1977-01-01

A procedure is presented for synthesizing time-invariant control logic to cause the outputs of a linear plant to track the outputs of an unforced (or randomly forced) linear dynamic system. The control logic uses feed-forward of the reference system state variables and feedback of the plant state variables. The feed-forward gains are obtained from the solution of a linear algebraic matrix equation of the Liapunov type. The feedback gains are the usual regulator gains, determined to stabilize (or augment the stability of) the plant, possibly including integral control. The method is applied here to the design of control logic for a second-order servomechanism to follow a linearly increasing (ramp) signal, an unstable third-order system with two controls to track two separate ramp signals, and a sixth-order system with two controls to track a constant signal and an exponentially decreasing signal (aircraft landing-flare or glide-slope-capture with constant velocity).

Virtual and Augmented Reality Systems for Renal Interventions: A Systematic Review.

PubMed

Detmer, Felicitas J; Hettig, Julian; Schindele, Daniel; Schostak, Martin; Hansen, Christian

2017-01-01

Many virtual and augmented reality systems have been proposed to support renal interventions. This paper reviews such systems employed in the treatment of renal cell carcinoma and renal stones. A systematic literature search was performed. Inclusion criteria were virtual and augmented reality systems for radical or partial nephrectomy and renal stone treatment, excluding systems solely developed or evaluated for training purposes. In total, 52 research papers were identified and analyzed. Most of the identified literature (87%) deals with systems for renal cell carcinoma treatment. About 44% of the systems have already been employed in clinical practice, but only 20% in studies with ten or more patients. Main challenges remaining for future research include the consideration of organ movement and deformation, human factor issues, and the conduction of large clinical studies. Augmented and virtual reality systems have the potential to improve safety and outcomes of renal interventions. In the last ten years, many technical advances have led to more sophisticated systems, which are already applied in clinical practice. Further research is required to cope with current limitations of virtual and augmented reality assistance in clinical environments.

Optimization of cutting parameters for machining time in turning process

NASA Astrophysics Data System (ADS)

Mavliutov, A. R.; Zlotnikov, E. G.

2018-03-01

This paper describes the most effective methods for nonlinear constraint optimization of cutting parameters in the turning process. Among them are Linearization Programming Method with Dual-Simplex algorithm, Interior Point method, and Augmented Lagrangian Genetic Algorithm (ALGA). Every each of them is tested on an actual example – the minimization of production rate in turning process. The computation was conducted in the MATLAB environment. The comparative results obtained from the application of these methods show: The optimal value of the linearized objective and the original function are the same. ALGA gives sufficiently accurate values, however, when the algorithm uses the Hybrid function with Interior Point algorithm, the resulted values have the maximal accuracy.

Structural, electronic, elastic, thermoelectric and thermodynamic properties of the NbMSb half heusler (M=Fe, Ru, Os) compounds with first principle calculations

NASA Astrophysics Data System (ADS)

Abid, O. Miloud; Menouer, S.; Yakoubi, A.; Khachai, H.; Omran, S. Bin; Murtaza, G.; Prakash, Deo; Khenata, R.; Verma, K. D.

2016-05-01

The structural, electronic, elastic, thermoelectric and thermodynamic properties of NbMSb (M = Fe, Ru, Os) half heusler compounds are reported. The full-potential linearized augmented plane wave (FP-LAPW) plus local orbital (lo) method, based on the density functional theory (DFT) was employed for the present study. The equilibrium lattice parameter results are in good compliance with the available experimental measurements. The electronic band structure and Boltzmann transport calculations indicated a narrow indirect energy band gap for the compound having electronic structure favorable for thermoelectric performance as well as with substantial thermopowers at temperature ranges from 300 K to 800 K. Furthermore, good potential for thermoelectric performance (thermopower S ≥ 500 μeV) was found at higher temperature. In addition, the analysis of the charge density, partial and total densities of states (DOS) of three compounds demonstrate their semiconducting, ionic and covalent characters. Conversely, the calculated values of the Poisson's ratio and the B/G ratio indicate their ductile makeup. The thermal properties of the compounds were calculated by quasi-harmonic Debye model as implemented in the GIBBS code.

X-ray diffraction, crystal structure, and spectral features of the optical susceptibilities of single crystals of the ternary borate oxide lead bismuth tetraoxide, PbBiBO4.

PubMed

Reshak, Ali Hussain; Kityk, I V; Auluck, S; Chen, Xuean

2009-05-14

The all-electron full-potential linearized augmented plane-wave method has been used for an ab initio theoretical study of the band structure, the spectral features of the optical susceptibilities, the density of states, and the electron charge density for PbBiBO4. Our calculations show that the valence-band maximum (VBM) and conduction-band minimum (CBM) are located at the center of the Brillouin zone, resulting in a direct energy gap of about 3.2 eV. We have synthesized the PbBiBO4 crystal by employing a conventional solid-state reaction method. The theoretical calculations in this work are based on the structure built from our measured atomic parameters. We should emphasize that the observed experimental X-ray diffraction (XRD) pattern is in good agreement with the theoretical one, confirming that our structural model is valid. Our calculated bond lengths show excellent agreement with the experimental data. This agreement is attributed to our use of full-potential calculations. The spectral features of the optical susceptibilities show a small positive uniaxial anisotropy.

Electronic and magnetic properties of double perovskite Sr2CoUO6: Heisenberg model

NASA Astrophysics Data System (ADS)

Nid-bahami, A.; Ahmed, S. Sidi; Ait-Tamerd, M.; Zaari, H.; El Kenz, A.; Benyoussef, A.

2018-01-01

This work will be focused on the electronic and magnetic properties of Sr2CoUO6 (SCUO) using ab-initio calculations and Monte Carlo Simulation (MCS). Firstly, we calculate the exchange coupling and the crystal field, then, the electronic and magnetic properties will be studied, using the full-potential linearized augmented plane wave (FP-LAPW) method, as implemented in the Wien2k code. This method employing the generalized gradient approximation (GGA) for exchange-correlation term. The half-metallic ferromagnetic nature implies a potential application of this new compound in spintronics devices. Also, we have presented the results of the band structures and densities of states for the two up and down spin polarizations. The exchange coupling and the crystal field calculated are J = 0 . 567 meV and δ = 0 . 559meV, and total spin magnetic moments is 2.96 μB closed to experimental values 3 μB. Secondly, we have presented the results for the magnetization and the susceptibility as a function of temperature. Finally, we obtain the critical temperature T = 9 . 20 K by MCS in good agreement with the experimental value.

Advanced millimeter-wave security portal imaging techniques

NASA Astrophysics Data System (ADS)

Sheen, David M.; Bernacki, Bruce E.; McMakin, Douglas L.

2012-03-01

Millimeter-wave (mm-wave) imaging is rapidly gaining acceptance as a security tool to augment conventional metal detectors and baggage x-ray systems for passenger screening at airports and other secured facilities. This acceptance indicates that the technology has matured; however, many potential improvements can yet be realized. The authors have developed a number of techniques over the last several years including novel image reconstruction and display techniques, polarimetric imaging techniques, array switching schemes, and high-frequency high-bandwidth techniques. All of these may improve the performance of new systems; however, some of these techniques will increase the cost and complexity of the mm-wave security portal imaging systems. Reducing this cost may require the development of novel array designs. In particular, RF photonic methods may provide new solutions to the design and development of the sequentially switched linear mm-wave arrays that are the key element in the mm-wave portal imaging systems. Highfrequency, high-bandwidth designs are difficult to achieve with conventional mm-wave electronic devices, and RF photonic devices may be a practical alternative. In this paper, the mm-wave imaging techniques developed at PNNL are reviewed and the potential for implementing RF photonic mm-wave array designs is explored.

Impact of anion replacement on the optoelectronic and thermoelectric properties of CaMg2X2, X= (N, P, As, Sb, Bi) compounds

NASA Astrophysics Data System (ADS)

Khan, Abdul Ahad; Yaseen, M.; Laref, A.; Murtaza, G.

2018-07-01

The structural, electronic, optical and thermoelectric properties of ternary CaMg2X2 (X = N, P, As, Sb and Bi) compounds are investigated using all electrons full potential linearized augment plane wave method. By using generalized gradient approximation (GGA), unit cell volumes of the compounds are optimized. For calculations of optical and electronic properties the modified Becke Johnson exchange potential is used along with the GGA. The direct energy band gap decreases by replacing the pnictogen elements, while indirect bandgap also decreases except for CaMg2As2. The optical properties show a prominent variation over the change of anion from N to Bi. There is inverse variation between refractive index and the band gap. The refractive indices of these compounds are high in the visible region and sharply decreased in the ultraviolet region. The thermoelectric properties are also studied using Boltzmann statistics through BoltzTrap code. A positive non-zero value of Seebeck coefficient shows a P-type semiconducting behavior of these compounds. High figure of merits (ZT) and optical conductivity peaks for all compounds reveal that they are good candidates for the thermo-electric and optoelectronics devices.

A full-dimensional ab initio potential energy surface and rovibrational energies of the Ar–HF complex

NASA Astrophysics Data System (ADS)

Huang, Jing; Zhou, Yanzi; Xie, Daiqian

2018-04-01

We report a new full-dimensional ab initio potential energy surface for the Ar-HF van der Waals complex at the level of coupled-cluster singles and doubles with noniterative inclusion of connected triples levels [CCSD(T)] using augmented correlation-consistent quintuple-zeta basis set (aV5Z) plus bond functions. Full counterpoise correction was employed to correct the basis-set superposition error. The hypersurface was fitted using artificial neural network method with a root mean square error of 0.1085 cm-1 for more than 8000 ab initio points. The complex was found to prefer a linear Ar-H-F equilibrium structure. The three-dimensional discrete variable representation method and the Lanczos propagation algorithm were then employed to calculate the rovibrational states without separating inter- and intra- molecular nuclear motions. The calculated vibrational energies of Ar-HF differ from the experiment values within about 1 cm-1 on the first four HF vibrational states, and the predicted pure rotational energies on (0000) and (1000) vibrational states are deviated from the observed value by about 1%, which shows the accuracy of our new PES.

Augmented and virtual reality in surgery—the digital surgical environment: applications, limitations and legal pitfalls

PubMed Central

Baker, Benjamin; Amin, Kavit; Chan, Adrian; Patel, Ketan; Wong, Jason

2016-01-01

The continuing enhancement of the surgical environment in the digital age has led to a number of innovations being highlighted as potential disruptive technologies in the surgical workplace. Augmented reality (AR) and virtual reality (VR) are rapidly becoming increasingly available, accessible and importantly affordable, hence their application into healthcare to enhance the medical use of data is certain. Whether it relates to anatomy, intraoperative surgery, or post-operative rehabilitation, applications are already being investigated for their role in the surgeons armamentarium. Here we provide an introduction to the technology and the potential areas of development in the surgical arena. PMID:28090510

Augmented and virtual reality in surgery-the digital surgical environment: applications, limitations and legal pitfalls.

PubMed

Khor, Wee Sim; Baker, Benjamin; Amin, Kavit; Chan, Adrian; Patel, Ketan; Wong, Jason

2016-12-01

The continuing enhancement of the surgical environment in the digital age has led to a number of innovations being highlighted as potential disruptive technologies in the surgical workplace. Augmented reality (AR) and virtual reality (VR) are rapidly becoming increasingly available, accessible and importantly affordable, hence their application into healthcare to enhance the medical use of data is certain. Whether it relates to anatomy, intraoperative surgery, or post-operative rehabilitation, applications are already being investigated for their role in the surgeons armamentarium. Here we provide an introduction to the technology and the potential areas of development in the surgical arena.

Augmented reality cube game for cognitive training: an interaction study.

PubMed

Boletsis, Costas; Mccallum, Simon

2014-01-01

There is the potential that cognitive activity may delay cognitive decline in people with mild cognitive impairment. Games provide both cognitive challenge and motivation for repeated use, a prerequisite for long lasting effect. Recent advances in technology introduce several new interaction methods, potentially leading to more efficient, personalized cognitive gaming experiences. In this paper, we present an Augmented Reality (AR) cognitive training game, utilizing cubes as input tools, and we test the cube interaction with a pilot study. The results of the study revealed the marker occlusion problem, and that novice AR users can adjust to the developed AR environment after a small number of sessions.

Applications of Mesenchymal Stem Cells in Sinus Lift Augmentation as a Dental Implant Technology.

PubMed

Parnia, Feridoun; Yazdani, Javad; Maleki Dizaj, Solmaz

2018-01-01

The potential application of stem cell biology in human dentistry is a new and emerging field of research. The objective of the current review was to study the efficiency of mesenchymal stem cells (MSCs) in sinus lift augmentation (SLA). A literature review was performed in PubMed Central using MeSH keywords such as sinus lift, MSCs, dental implants, and augmentation. The searches involved full-text papers written in English, published in the past 10 years (2007-2017). The review included in vitro and in vivo studies on the use of MSCs in SLA. Electronic searching provided 45 titles, and among them, 8 papers were chosen as suitable based on the inclusion requirements of this review. The reviewed studies have revealed the potential of MSCs in SLA. According to these papers, stem cell therapy combined with different biomaterials may considerably improve bone regeneration in previous steps of dental implantation and may veritably lead to efficient clinical usages in the recent future. However, the identification of an ideal source of stem cells as well as long-term studies is vital to assess the success rate of this technology. Further clinical trials are also needed to approve the potential of MSCs in SLA.

An experimental test of alternative population augmentation scenarios.

PubMed

Kronenberger, John A; Gerberich, Jill C; Fitzpatrick, Sarah W; Broder, E Dale; Angeloni, Lisa M; Funk, W Chris

2018-01-19

Human land use is fragmenting habitats worldwide and inhibiting dispersal among previously connected populations of organisms, often leading to inbreeding depression and reduced evolutionary potential in the face of rapid environmental change. To combat this augmentation of isolated populations with immigrants is sometimes used to facilitate demographic and genetic rescue. Augmentation with immigrants that are genetically and adaptively similar to the target population effectively increases population fitness, but if immigrants are very genetically or adaptively divergent, augmentation can lead to outbreeding depression. Despite well-cited guidelines for the best practice selection of immigrant sources, often only highly divergent populations remain, and experimental tests of these riskier augmentation scenarios are essentially nonexistent. We conducted a mesocosm experiment with Trinidadian guppies (Poecilia reticulata) to test the multigenerational demographic and genetic effects of augmenting 2 target populations with 3 types of divergent immigrants. We found no evidence of demographic rescue, but we did observe genetic rescue in one population. Divergent immigrant treatments tended to maintain greater genetic diversity, abundance, and hybrid fitness than controls that received immigrants from the source used to seed the mesocosms. In the second population, divergent immigrants had a slightly negative effect in one treatment, and the benefits of augmentation were less apparent overall, likely because this population started with higher genetic diversity and a lower reproductive rate that limited genetic admixture. Our results add to a growing consensus that gene flow can increase population fitness even when immigrants are more highly divergent and may help reduce uncertainty about the use of augmentation in conservation. © 2018 Society for Conservation Biology.

Prophylactic augmentation of the proximal femur: an investigation of two techniques.

PubMed

Raas, Christoph; Hofmann-Fliri, Ladina; Hörmann, Romed; Schmoelz, Werner

2016-03-01

Osteoporotic hip fractures are an increasing problem in an ageing population. They result in high morbidity, mortality and high socioeconomic costs. For patients with poor bone quality, prophylactic augmentation of the proximal femur might be an option for fracture prevention. In two groups of paired human femora the potential of limited polymethyl-methacrylate (PMMA) augmentation (11-15 ml) in a V-shape pattern and the insertion of a proximal femur nail antirotation (PFNA) blade were investigated. The testing was carried out pair wise simulating the single leg stand. The untreated femur in each pair served as control. An axial load was applied until failure. Load displacement parameters and temperature increase during the augmentation process were recorded. In the PMMA group no significant difference was found between the augmented and non-augmented specimen concerning load to failure (p = 0.35) and energy to failure (p = 0.9). A median temperature increase of 9.5 °C was observed in the augmented specimen. A significant correlation was found between the amount of applied PMMA and the temperature increase (Cor. Coef. = 0.82, p = 0.042). In the PFNA group, a significant decrease of load to failure and a non-significant decrease of energy to failure were observed (p = 0.037 and p = 0.075). Limited V-shaped PMMA augmentation and PFNA blade insertion did not show any improvement in failure load or energy to failure. Volumes of up to 15 ml PMMA did not cause a critical surface temperature increase.

Type 2 diabetes impairs the ability of skeletal muscle pericytes to augment postischemic neovascularization in db/db mice.

PubMed

Hayes, Katherine L; Messina, Louis M; Schwartz, Lawrence M; Yan, Jinglian; Burnside, Amy S; Witkowski, Sarah

2018-05-01

Peripheral artery disease is an atherosclerotic occlusive disease that causes limb ischemia and has few effective noninterventional treatments. Stem cell therapy is promising, but concomitant diabetes may limit its effectiveness. We evaluated the therapeutic potential of skeletal muscle pericytes to augment postischemic neovascularization in wild-type and type 2 diabetic (T2DM) mice. Wild-type C57BL/6J and leptin receptor spontaneous mutation db/db T2DM mice underwent unilateral femoral artery excision to induce limb ischemia. Twenty-four hours after ischemia induction, CD45 - CD34 - CD146 + skeletal muscle pericytes or vehicle controls were transplanted into ischemic hindlimb muscles. At postoperative day 28, pericyte transplantation augmented blood flow recovery in wild-type mice (79.3 ± 5% vs. 61.9 ± 5%; P = 0.04), but not in T2DM mice (48.6% vs. 46.3 ± 5%; P = 0.51). Pericyte transplantation augmented collateral artery enlargement in wild-type (26.7 ± 2 μm vs. 22.3 ± 1 μm, P = 0.03), but not T2DM mice (20.4 ± 1.4 μm vs. 18.5 ± 1.2 μm, P = 0.14). Pericyte incorporation into collateral arteries was higher in wild-type than in T2DM mice ( P = 0.002). Unexpectedly, pericytes differentiated into Schwann cells in vivo. In vitro, Insulin increased Nox2 expression and decreased tubular formation capacity in human pericytes. These insulin-induced effects were reversed by N-acetylcysteine antioxidant treatment. In conclusion, T2DM impairs the ability of pericytes to augment neovascularization via decreased collateral artery enlargement and impaired engraftment into collateral arteries, potentially via hyperinsulinemia-induced oxidant stress. While pericytes show promise as a unique form of stem cell therapy to increase postischemic neovascularization, characterizing the molecular mechanisms by which T2DM impairs their function is essential to achieve their therapeutic potential.

Vascularized interpositional periosteal connective tissue flap: A modern approach to augment soft tissue

PubMed Central

Agarwal, Chitra; Deora, Savita; Abraham, Dennis; Gaba, Rohini; Kumar, Baron Tarun; Kudva, Praveen

2015-01-01

Context: Nowadays esthetics plays an important role in dentistry along with function of the prosthesis. Various soft tissue augmentation procedures are available to correct the ridge defects in the anterior region. The newer technique, vascularized interpositional periosteal connective tissue (VIP-CT) flap has been introduced, which has the potential to augment predictable amount of tissue and has many benefits when compared to other techniques. Aim: The study was designed to determine the efficacy of the VIP-CT flap in augmenting the ridge defect. Materials and Methods: Ten patients with Class III (Seibert's) ridge defects were treated with VIP-CT flap technique before fabricating fixed partial denture. Height and width of the ridge defects were measured before and after the procedure. Subsequent follow-up was done every 3 months for 1-year. Statistical Analysis Used: Paired t-test was performed to detect the significance of the procedure. Results: The surgical site healed uneventfully. The predictable amount of soft tissue augmentation had been achieved with the procedure. The increase in height and width of the ridge was statistically highly significant. Conclusion: The VIP-CT flap technique was effective in augmenting the soft tissue in esthetic area that remained stable over a long period. PMID:25810597

A novel augmented reality system for displaying inferior alveolar nerve bundles in maxillofacial surgery

PubMed Central

Zhu, Ming; Liu, Fei; Chai, Gang; Pan, Jun J.; Jiang, Taoran; Lin, Li; Xin, Yu; Zhang, Yan; Li, Qingfeng

2017-01-01

Augmented reality systems can combine virtual images with a real environment to ensure accurate surgery with lower risk. This study aimed to develop a novel registration and tracking technique to establish a navigation system based on augmented reality for maxillofacial surgery. Specifically, a virtual image is reconstructed from CT data using 3D software. The real environment is tracked by the augmented reality (AR) software. The novel registration strategy that we created uses an occlusal splint compounded with a fiducial marker (OSM) to establish a relationship between the virtual image and the real object. After the fiducial marker is recognized, the virtual image is superimposed onto the real environment, forming the “integrated image” on semi-transparent glass. Via the registration process, the integral image, which combines the virtual image with the real scene, is successfully presented on the semi-transparent helmet. The position error of this navigation system is 0.96 ± 0.51 mm. This augmented reality system was applied in the clinic and good surgical outcomes were obtained. The augmented reality system that we established for maxillofacial surgery has the advantages of easy manipulation and high accuracy, which can improve surgical outcomes. Thus, this system exhibits significant potential in clinical applications. PMID:28198442

A novel augmented reality system for displaying inferior alveolar nerve bundles in maxillofacial surgery.

PubMed

Zhu, Ming; Liu, Fei; Chai, Gang; Pan, Jun J; Jiang, Taoran; Lin, Li; Xin, Yu; Zhang, Yan; Li, Qingfeng

2017-02-15

Augmented reality systems can combine virtual images with a real environment to ensure accurate surgery with lower risk. This study aimed to develop a novel registration and tracking technique to establish a navigation system based on augmented reality for maxillofacial surgery. Specifically, a virtual image is reconstructed from CT data using 3D software. The real environment is tracked by the augmented reality (AR) software. The novel registration strategy that we created uses an occlusal splint compounded with a fiducial marker (OSM) to establish a relationship between the virtual image and the real object. After the fiducial marker is recognized, the virtual image is superimposed onto the real environment, forming the "integrated image" on semi-transparent glass. Via the registration process, the integral image, which combines the virtual image with the real scene, is successfully presented on the semi-transparent helmet. The position error of this navigation system is 0.96 ± 0.51 mm. This augmented reality system was applied in the clinic and good surgical outcomes were obtained. The augmented reality system that we established for maxillofacial surgery has the advantages of easy manipulation and high accuracy, which can improve surgical outcomes. Thus, this system exhibits significant potential in clinical applications.

Effect of doping on electronic properties of HgSe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nag, Abhinav, E-mail: abhinavn76@gmail.com; Sastri, O. S. K. S., E-mail: sastri.osks@gmail.com; Kumar, Jagdish, E-mail: jagdishphysicist@gmail.com

2016-05-23

First principle study of electronic properties of pure and doped HgSe have been performed using all electron Full Potential Linearized Augmented Plane Wave (FP-LAPW) method using ELK code. The electronic exchange and co-relations are considered using Generalized Gradient Approach (GGA). Lattice parameter, Density of States (DOS) and Band structure calculations have been performed. The total energy curve (Energy vs Lattice parameter), DOS and band structure calculations are in good agreement with the experimental values and those obtained using other DFT codes. The doped material is studied within the Virtual Crystal Approximation (VCA) with doping levels of 10% to 25% ofmore » electrons (hole) per unit cell. Results predict zero band gap in undopedHgSe and bands meet at Fermi level near the symmetry point Γ. For doped HgSe, we found that by electron (hole) doping, the point where conduction and valence bands meet can be shifted below (above) the fermi level.« less

Translational systems pharmacology‐based predictive assessment of drug‐induced cardiomyopathy

PubMed Central

Messinis, Dimitris E.; Melas, Ioannis N.; Hur, Junguk; Varshney, Navya; Alexopoulos, Leonidas G.

2018-01-01

Drug‐induced cardiomyopathy contributes to drug attrition. We compared two pipelines of predictive modeling: (1) applying elastic net (EN) to differentially expressed genes (DEGs) of drugs; (2) applying integer linear programming (ILP) to construct each drug's signaling pathway starting from its targets to downstream proteins, to transcription factors, and to its DEGs in human cardiomyocytes, and then subjecting the genes/proteins in the drugs' signaling networks to EN regression. We classified 31 drugs with availability of DEGs into 13 toxic and 18 nontoxic drugs based on a clinical cardiomyopathy incidence cutoff of 0.1%. The ILP‐augmented modeling increased prediction accuracy from 79% to 88% (sensitivity: 88%; specificity: 89%) under leave‐one‐out cross validation. The ILP‐constructed signaling networks of drugs were better predictors than DEGs. Per literature, the microRNAs that reportedly regulate expression of our six top predictors are of diagnostic value for natural heart failure or doxorubicin‐induced cardiomyopathy. This translational predictive modeling might uncover potential biomarkers. PMID:29341478

Band-gap tuning and optical response of two-dimensional Si x C 1 - x : A first-principles real-space study of disordered two-dimensional materials

DOE PAGES

Sadhukhan, Banasree; Singh, Prashant; Nayak, Arabinda; ...

2017-08-09

We present a real-space formulation for calculating the electronic structure and optical conductivity of random alloys based on Kubo-Greenwood formalism interfaced with augmented space recursion technique formulated with the tight-binding linear muffin-tin orbital basis with the van Leeuwen–Baerends corrected exchange potential. This approach has been used to quantitatively analyze the effect of chemical disorder on the configuration averaged electronic properties and optical response of two-dimensional honeycomb siliphene Si xC 1–x beyond the usual Dirac-cone approximation. We predicted the quantitative effect of disorder on both the electronic structure and optical response over a wide energy range, and the results are discussedmore » in the light of the available experimental and other theoretical data. As a result, our proposed formalism may open up a facile way for planned band-gap engineering in optoelectronic applications.« less

Electronic and optical properties of graphene-like InAs: An ab initio study

NASA Astrophysics Data System (ADS)

Sohrabi, Leila; Boochani, Arash; Ali Sebt, S.; Mohammad Elahi, S.

2018-03-01

The present work initially investigates structural, optical, and electronic properties of graphene-like InAs by using the full potential linear augmented plane wave method in the framework of density functional theory and is then compared with the bulk Indium Arsenide in the wurtzite phase. The lattice parameters are optimized with GGA-PBE and LDA approximations for both 2D- and 3D-InAs. In order to study the electronic properties of graphene-like InAs and bulk InAs in the wurtzite phase, the band gap is calculated by GGA-PBG and GGA-EV approximations. Moreover, optical parameters of graphene-like InAs and bulk InAs such as the real and imaginary parts of dielectric function, electron energy loss function, refractivity, extinction and absorption coefficients, and optical conductivity are investigated. Plasmonic frequencies of 2D- and 3D-InAs are also calculated by using maximum electron energy loss function and the roots of the real part of the dielectric function.

FP-LAPW calculations of the elastic, electronic and thermoelectric properties of the filled skutterudite CeRu{sub 4}Sb{sub 12}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shankar, A., E-mail: amitshan2009@gmail.com; Rai, D.P.; Chettri, Sandeep

2016-08-15

We have investigated the electronic structure, elastic and thermoelectric properties of the filled skutterudite CeRu{sub 4}Sb{sub 12} using the density functional theory (DFT). The full potential linearized augmented plane wave (FP-LAPW) method within a framework of the generalized gradient approximation (GGA) approach is used to perform the calculations presented here. The electronic structure calculation suggests an indirect band gap semiconducting nature of the material with energy band gap of 0.08 eV. The analysis of the elastic constants at relaxed positions reveals the ductile nature of the sample material with covalent contribution in the inter-atomic bonding. The narrow band gap semiconductingmore » nature with high value of Seebeck coefficient suggests the possibility of the thermoelectric application of the material. The analysis of the thermal transport properties confirms the result obtained from the energy band structure of the material with high thermopower and dimensionless figure of merit 0.19 at room temperature.« less

Thermoelectric properties of doped BaHfO{sub 3}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dixit, Chandra Kr., E-mail: ckparadise@gmail.com, E-mail: sharmarameshfgiet@gmail.com; Bhamu, K. C.; Sharma, Ramesh, E-mail: ckparadise@gmail.com, E-mail: sharmarameshfgiet@gmail.com

2016-05-06

We have studied the structural stability, electronic structure, optical properties and thermoelectric properties of doped BaHfO{sub 3} by full potential linearized augmented plane wave (FP-LAPW) method. The electronic structure of BaHfO{sub 3} doped with Sr shows enhances the indirect band gaps of 3.53 eV, 3.58 eV. The charge density plots show strong ionic bonding in Ba-Hf, and ionic and covalent bonding between Hf and O. Calculations of the optical spectra, viz., the dielectric function, refractive index and extinction coefficient are performed for the energy range are calculated and analyzed. Thermoelectric properties of semi conducting are also reported first time. Themore » doped BaHfO{sub 3} is approximately wide band gap semiconductor with the large p-type Seebeck coefficient. The power factor of BaHfO{sub 3} is increased with Sr doping, decreases because of low electrical resistivity and thermal conductivity.« less

Computational attributes of the integral form of the equation of transfer

NASA Technical Reports Server (NTRS)

Frankel, J. I.

1991-01-01

Difficulties can arise in radiative and neutron transport calculations when a highly anisotropic scattering phase function is present. In the presence of anisotropy, currently used numerical solutions are based on the integro-differential form of the linearized Boltzmann transport equation. This paper, departs from classical thought and presents an alternative numerical approach based on application of the integral form of the transport equation. Use of the integral formalism facilitates the following steps: a reduction in dimensionality of the system prior to discretization, the use of symbolic manipulation to augment the computational procedure, and the direct determination of key physical quantities which are derivable through the various Legendre moments of the intensity. The approach is developed in the context of radiative heat transfer in a plane-parallel geometry, and results are presented and compared with existing benchmark solutions. Encouraging results are presented to illustrate the potential of the integral formalism for computation. The integral formalism appears to possess several computational attributes which are well-suited to radiative and neutron transport calculations.

Electronic structure and optical properties of iron based chalcogenide FeX2 (X = S, Se, Te) for photovoltaic applications: a first principle study

NASA Astrophysics Data System (ADS)

Ghosh, Anima; Thangavel, R.

2017-11-01

In present work, the electronic structure and optical properties of the FeX2 (X = S, Se, Te) compounds have been evaluated by the density functional theory based on the scalar-relativistic full potential linear augmented plane wave method via Wien2K. From the total energy calculations, it has been found that all the compounds have direct band nature, which determined by iron 3 d states at valance band edge and anion p dominated at conduction band at Γ-point and the fundamental band gap between the valence band and conduction band are estimated 1.40, 1.02 and 0.88 eV respectively with scissor correction for FeS2, FeSe2 and FeTe2 which are close to the experimental values. The optical properties such as dielectric tensor components and the absorption coefficient of these materials are determined in order to investigate their usefulness in photovoltaic applications.

Band-gap tuning and optical response of two-dimensional Si x C 1 - x : A first-principles real-space study of disordered two-dimensional materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sadhukhan, Banasree; Singh, Prashant; Nayak, Arabinda

We present a real-space formulation for calculating the electronic structure and optical conductivity of random alloys based on Kubo-Greenwood formalism interfaced with augmented space recursion technique formulated with the tight-binding linear muffin-tin orbital basis with the van Leeuwen–Baerends corrected exchange potential. This approach has been used to quantitatively analyze the effect of chemical disorder on the configuration averaged electronic properties and optical response of two-dimensional honeycomb siliphene Si xC 1–x beyond the usual Dirac-cone approximation. We predicted the quantitative effect of disorder on both the electronic structure and optical response over a wide energy range, and the results are discussedmore » in the light of the available experimental and other theoretical data. As a result, our proposed formalism may open up a facile way for planned band-gap engineering in optoelectronic applications.« less

A globally convergent LCL method for nonlinear optimization.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Friedlander, M. P.; Saunders, M. A.; Mathematics and Computer Science

2005-01-01

For optimization problems with nonlinear constraints, linearly constrained Lagrangian (LCL) methods solve a sequence of subproblems of the form 'minimize an augmented Lagrangian function subject to linearized constraints.' Such methods converge rapidly near a solution but may not be reliable from arbitrary starting points. Nevertheless, the well-known software package MINOS has proved effective on many large problems. Its success motivates us to derive a related LCL algorithm that possesses three important properties: it is globally convergent, the subproblem constraints are always feasible, and the subproblems may be solved inexactly. The new algorithm has been implemented in Matlab, with an optionmore » to use either MINOS or SNOPT (Fortran codes) to solve the linearly constrained subproblems. Only first derivatives are required. We present numerical results on a subset of the COPS, HS, and CUTE test problems, which include many large examples. The results demonstrate the robustness and efficiency of the stabilized LCL procedure.« less

Fault detection for singular switched linear systems with multiple time-varying delay in finite frequency domain

NASA Astrophysics Data System (ADS)

Zhai, Ding; Lu, Anyang; Li, Jinghao; Zhang, Qingling

2016-10-01

This paper deals with the problem of the fault detection (FD) for continuous-time singular switched linear systems with multiple time-varying delay. In this paper, the actuator fault is considered. Besides, the systems faults and unknown disturbances are assumed in known frequency domains. Some finite frequency performance indices are initially introduced to design the switched FD filters which ensure that the filtering augmented systems under switching signal with average dwell time are exponentially admissible and guarantee the fault input sensitivity and disturbance robustness. By developing generalised Kalman-Yakubovic-Popov lemma and using Parseval's theorem and Fourier transform, finite frequency delay-dependent sufficient conditions for the existence of such a filter which can guarantee the finite-frequency H- and H∞ performance are derived and formulated in terms of linear matrix inequalities. Four examples are provided to illustrate the effectiveness of the proposed finite frequency method.

Use of augmentative and alternative communication strategies by family members in the intensive care unit.

PubMed

Broyles, Lauren M; Tate, Judith A; Happ, Mary Beth

2012-03-01

Little is known about communication between patients and their family members during critical illness and mechanical ventilation in the intensive care unit, including use of augmentative and alternative communication tools and strategies. To identify (1) which augmentative and alternative communication tools families use with nonspeaking intensive care patients and how they are used, and (2) what families and nurses say about communication of family members with nonspeaking intensive care patients. A qualitative secondary analysis was conducted of existing data from a clinical trial testing interventions to improve communication between nurses and intensive care patients. Narrative study data (field notes, intervention logs, nurses' interviews) from 127 critically ill adults were reviewed for evidence of family involvement with augmentative and alternative communication tools. Qualitative content analysis was applied for thematic description of family members' and nurses' accounts of patient-family communication. Family involvement with augmentative and alternative communication tools was evident in 44% of the 93 patients who completed the parent study protocol. Spouses or significant others communicated with patients most often. Main themes describing patient-family communication included (1) families being unprepared and unaware, (2) families' perceptions of communication effectiveness, (3) nurses deferring to or guiding patient-family communication, (4) patients' communication characteristics, and (5) families' experience with and interest in augmentative and alternative communication tools. Assessment by skilled bedside clinicians can reveal patients' communication potential and facilitate useful augmentative and alternative communication tools and strategies for patients and their families.

In-Flight Suppression of a Destabilized F/A-18 Structural Mode Using the Space Launch System Adaptive Augmenting Control System

NASA Technical Reports Server (NTRS)

Wall, John H.; VanZwieten, Tannen S.; Gilligan, Eric T.; Miller, Christopher J.; Hanson, Curtis E.; Orr, Jeb S.

2015-01-01

NASA's Space Launch System (SLS) Flight Control System (FCS) includes an Adaptive Augmenting Control (AAC) component which employs a multiplicative gain update law to enhance the performance and robustness of the baseline control system for extreme off nominal scenarios. The SLS FCS algorithm including AAC has been flight tested utilizing a specially outfitted F/A-18 fighter jet in which the pitch axis control of the aircraft was performed by a Non-linear Dynamic Inversion (NDI) controller, SLS reference models, and the SLS flight software prototype. This paper describes test cases from the research flight campaign in which the fundamental F/A-18 airframe structural mode was identified using frequency-domain reconstruction of flight data, amplified to result in closed loop instability, and suppressed in-flight by the SLS adaptive control system.

Inverse sequential procedures for the monitoring of time series

NASA Technical Reports Server (NTRS)

Radok, Uwe; Brown, Timothy

1993-01-01

Climate changes traditionally have been detected from long series of observations and long after they happened. The 'inverse sequential' monitoring procedure is designed to detect changes as soon as they occur. Frequency distribution parameters are estimated both from the most recent existing set of observations and from the same set augmented by 1,2,...j new observations. Individual-value probability products ('likelihoods') are then calculated which yield probabilities for erroneously accepting the existing parameter(s) as valid for the augmented data set and vice versa. A parameter change is signaled when these probabilities (or a more convenient and robust compound 'no change' probability) show a progressive decrease. New parameters are then estimated from the new observations alone to restart the procedure. The detailed algebra is developed and tested for Gaussian means and variances, Poisson and chi-square means, and linear or exponential trends; a comprehensive and interactive Fortran program is provided in the appendix.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Unseren, M.A.

A general framework for solving the dynamic load distribution when two manipulators hold a rigid object is proposed. The underspecified problem of solving for the contact forces and torques based on the object`s equations of motion is transformed into a well specified problem. This is accomplished by augmenting the object`s equations of motion with additional equations which relate a new vector variable quantifying the internal contact force and torque degrees of freedom (DOF) as a linear function of the contact forces and torques. The resulting augmented system yields a well specified solution for the contact forces and torques in whichmore » they are separated into their motion inducing and internal components. A particular solution is suggested which enables the designer to conveniently specify what portion of the payload`s mass each manipulator is to bear. It is also shown that the results of the previous work are just a special case of the general load distribution framework described here.« less

Beam steering for virtual/augmented reality displays with a cycloidal diffractive waveplate.

PubMed

Chen, Haiwei; Weng, Yishi; Xu, Daming; Tabiryan, Nelson V; Wu, Shin-Tson

2016-04-04

We proposed a switchable beam steering device with cycloidal diffractive waveplate (CDW) for eye tracking in a virtual reality (VR) or augmented reality (AR) display system. Such a CDW diffracts the incident circularly polarized light to the first order with over 95% efficiency. To convert the input linearly polarized light to right-handed or left-handed circular polarization, we developed a broadband polarization switch consisting of a twisted nematic liquid crystal cell and an achromatic quarter-wave retardation film. By cascading 2-3 CDWs together, multiple diffraction angles can be achieved. To suppress the color dispersion, we proposed two approaches to obtain the same diffraction angle for red, green, and blue LEDs-based full color displays. Our device exhibits several advantages, such as high diffraction efficiency, fast response time, low power consumption, and low cost. It holds promise for the emerging VR/AR displays.

Electronic structure and defect properties of hybrid chalcohalides Hg3Q2I2 (Q =S, Se and Te) for radiation detection

NASA Astrophysics Data System (ADS)

Kontsevoi, Oleg Y.; He, Yihui; Wessels, Bruce W.; Kanatzidis, Mercouri G.

Heavy metal chalcohalides Hg3Q2I2 (Q =S, Se and Te) have shown significant promise as X-ray and γ-ray detector materials. To assess the fundamental physical properties important for their performance as detectors, theoretical calculations were performed for the electronic structure, band gaps, electron and hole effective masses, and native defect properties. The calculations were based on first-principles density functional theory (DFT) and employ the highly precise full potential linearized augmented plane wave method and the projector augmented wave method and include nonlocal exchange-correlation functionals to overcome the band gap underestimation in DFT calculations. The calculations show that Hg3Q2I2 have either indirect (Q =S, Se) or direct (Q =Te) band gaps within 1.9-2.25 range which is optimal for a detector material, and very small electron effective masses (0.19 m0 for Hg3Se2I2) which could result in a good carrier mobility-lifetime product μτ . We further investigated a large set of native defects in the most promising candidate material, Hg3Se2I2, to determine the optimal growth conditions for application as γ-ray detectors. The results suggest that the prevalent intrinsic defects are iodine vacancies, mercury vacancies, and selenium vacancies followed by antisite defects. The effect of various chemical environments on defect properties was examined and the optimal conditions for material synthesis were suggested. Supported by DHS (Grant No. 2014-DN-077-ARI086-01).

Practice on an augmented reality/haptic simulator and library of virtual brains improves residents' ability to perform a ventriculostomy.

PubMed

Yudkowsky, Rachel; Luciano, Cristian; Banerjee, Pat; Schwartz, Alan; Alaraj, Ali; Lemole, G Michael; Charbel, Fady; Smith, Kelly; Rizzi, Silvio; Byrne, Richard; Bendok, Bernard; Frim, David

2013-02-01

Ventriculostomy is a neurosurgical procedure for providing therapeutic cerebrospinal fluid drainage. Complications may arise during repeated attempts at placing the catheter in the ventricle. We studied the impact of simulation-based practice with a library of virtual brains on neurosurgery residents' performance in simulated and live surgical ventriculostomies. Using computed tomographic scans of actual patients, we developed a library of 15 virtual brains for the ImmersiveTouch system, a head- and hand-tracked augmented reality and haptic simulator. The virtual brains represent a range of anatomies including normal, shifted, and compressed ventricles. Neurosurgery residents participated in individual simulator practice on the library of brains including visualizing the 3-dimensional location of the catheter within the brain immediately after each insertion. Performance of participants on novel brains in the simulator and during actual surgery before and after intervention was analyzed using generalized linear mixed models. Simulator cannulation success rates increased after intervention, and live procedure outcomes showed improvement in the rate of successful cannulation on the first pass. However, the incidence of deeper, contralateral (simulator) and third-ventricle (live) placements increased after intervention. Residents reported that simulations were realistic and helpful in improving procedural skills such as aiming the probe, sensing the pressure change when entering the ventricle, and estimating how far the catheter should be advanced within the ventricle. Simulator practice with a library of virtual brains representing a range of anatomies and difficulty levels may improve performance, potentially decreasing complications due to inexpert technique.

Need for, and financial feasibility of, satellite-aided land mobile communications

NASA Technical Reports Server (NTRS)

Castruccio, P. A.; Marantz, C. S.; Freibaum, J.

1982-01-01

Questions regarding the role of a mobile-satellite system in augmenting the terrestrial communications system are considered, and a market assessment study is discussed. Aspects of an investment analysis are examined, taking into account a three phase financial study of four postulated land Mobile Satellite Service (LMSS) systems, project profitability evaluation methods, risk analysis methods, financial projections, potential investor acceptance standards, and a risk analysis. It is concluded that a satellite augmented terrestrial mobile service appears to be economically and technically superior to a service depending exclusively on terrestrial systems. The interest in the Mobile Satellite Service is found to be worldwide, and the ground equipment market is potentially large.

Virtual patients in a real clinical context using augmented reality: impact on antibiotics prescription behaviors.

PubMed

Nifakos, Sokratis; Zary, Nabil

2014-01-01

The research community has called for the development of effective educational interventions for addressing prescription behaviour since antimicrobial resistance remains a global health issue. Examining the potential to displace the educational process from Personal Computers to Mobile devices, in this paper we investigated a new method of integration of Virtual Patients into Mobile devices with augmented reality technology, enriching the practitioner's education in prescription behavior. Moreover, we also explored which information are critical during the prescription behavior education and we visualized these information on real context with augmented reality technology, simultaneously with a running Virtual Patient's scenario. Following this process, we set the educational frame of experiential knowledge to a mixed (virtual and real) environment.

Robust control of integrated motor-transmission powertrain system over controller area network for automotive applications

NASA Astrophysics Data System (ADS)

Zhu, Xiaoyuan; Zhang, Hui; Cao, Dongpu; Fang, Zongde

2015-06-01

Integrated motor-transmission (IMT) powertrain system with directly coupled motor and gearbox is a good choice for electric commercial vehicles (e.g., pure electric buses) due to its potential in motor size reduction and energy efficiency improvement. However, the controller design for powertrain oscillation damping becomes challenging due to the elimination of damping components. On the other hand, as controller area network (CAN) is commonly adopted in modern vehicle system, the network-induced time-varying delays that caused by bandwidth limitation will further lead to powertrain vibration or even destabilize the powertrain control system. Therefore, in this paper, a robust energy-to-peak controller is proposed for the IMT powertrain system to address the oscillation damping problem and also attenuate the external disturbance. The control law adopted here is based on a multivariable PI control, which ensures the applicability and performance of the proposed controller in engineering practice. With the linearized delay uncertainties characterized by polytopic inclusions, a delay-free closed-loop augmented system is established for the IMT powertrain system under discrete-time framework. The proposed controller design problem is then converted to a static output feedback (SOF) controller design problem where the feedback control gains are obtained by solving a set of linear matrix inequalities (LMIs). The effectiveness as well as robustness of the proposed controller is demonstrated by comparing its performance against that of a conventional PI controller.

Ab initio calculations of the structural, electronic, thermodynamic and thermal properties of BaSe1-x Te x alloys

NASA Astrophysics Data System (ADS)

Drablia, S.; Boukhris, N.; Boulechfar, R.; Meradji, H.; Ghemid, S.; Ahmed, R.; Omran, S. Bin; El Haj Hassan, F.; Khenata, R.

2017-10-01

The alkaline earth metal chalcogenides are being intensively investigated because of their advanced technological applications, for example in photoluminescent devices. In this study, the structural, electronic, thermodynamic and thermal properties of the BaSe1-x Te x alloys at alloying composition x = 0, 0.25, 0.50, 0.75 and 1 are investigated. The full potential linearized augmented plane wave plus local orbital method designed within the density functional theory was used to perform the total energy calculations. In this research work the effect of the composition on the results of the parameters and bulk modulus as well as on the band gap energy is analyzed. From our results, we found a deviation of the obtained results for the lattice constants from Vegard’s law as well as a deviation of the value of the bulk modulus from the linear concentration dependence. We also carried out a microscopic analysis of the origin of the band gap energy bowing parameter. Furthermore, the thermodynamic stability of the considered alloys was explored through the measurement of the miscibility critical temperature. The quasi-harmonic Debye model, as implemented in the Gibbs code, was used to predict the thermal properties of the BaSe1-x Te x alloys, and these investigations comprise our first theoretical predictions concerning the BaSe1-x Te x alloys.

Improved methods in neural network-based adaptive output feedback control, with applications to flight control

NASA Astrophysics Data System (ADS)

Kim, Nakwan

Utilizing the universal approximation property of neural networks, we develop several novel approaches to neural network-based adaptive output feedback control of nonlinear systems, and illustrate these approaches for several flight control applications. In particular, we address the problem of non-affine systems and eliminate the fixed point assumption present in earlier work. All of the stability proofs are carried out in a form that eliminates an algebraic loop in the neural network implementation. An approximate input/output feedback linearizing controller is augmented with a neural network using input/output sequences of the uncertain system. These approaches permit adaptation to both parametric uncertainty and unmodeled dynamics. All physical systems also have control position and rate limits, which may either deteriorate performance or cause instability for a sufficiently high control bandwidth. Here we apply a method for protecting an adaptive process from the effects of input saturation and time delays, known as "pseudo control hedging". This method was originally developed for the state feedback case, and we provide a stability analysis that extends its domain of applicability to the case of output feedback. The approach is illustrated by the design of a pitch-attitude flight control system for a linearized model of an R-50 experimental helicopter, and by the design of a pitch-rate control system for a 58-state model of a flexible aircraft consisting of rigid body dynamics coupled with actuator and flexible modes. A new approach to augmentation of an existing linear controller is introduced. It is especially useful when there is limited information concerning the plant model, and the existing controller. The approach is applied to the design of an adaptive autopilot for a guided munition. Design of a neural network adaptive control that ensures asymptotically stable tracking performance is also addressed.

Modal control of an unstable periodic orbit

NASA Astrophysics Data System (ADS)

Wiesel, W.; Shelton, W.

1983-03-01

Floquet theory is applied to the problem of designing a control system for a satellite in an unstable periodic orbit. Expansion about a periodic orbit produces a time-periodic linear system, which is augmented by a time-periodic control term. It is shown that this can be done such that (1) the application of control produces only inertial accelerations, (2) positive real Poincareexponents are shifted into the left half-plane, and (3) the shift of the exponent is linear with control gain. These developments are applied to an unstable orbit near the earth-moon L(3) point pertubed by the sun. Finally, it is shown that the control theory can be extended to include first order perturbations about the periodic orbit without increase in control cost.

Modal control of an unstable periodic orbit

NASA Technical Reports Server (NTRS)

Wiesel, W.; Shelton, W.

1983-01-01

Floquet theory is applied to the problem of designing a control system for a satellite in an unstable periodic orbit. Expansion about a periodic orbit produces a time-periodic linear system, which is augmented by a time-periodic control term. It is shown that this can be done such that (1) the application of control produces only inertial accelerations, (2) positive real Poincareexponents are shifted into the left half-plane, and (3) the shift of the exponent is linear with control gain. These developments are applied to an unstable orbit near the earth-moon L(3) point pertubed by the sun. Finally, it is shown that the control theory can be extended to include first order perturbations about the periodic orbit without increase in control cost.

Nanostructures: a platform for brain repair and augmentation

PubMed Central

Vidu, Ruxandra; Rahman, Masoud; Mahmoudi, Morteza; Enachescu, Marius; Poteca, Teodor D.; Opris, Ioan

2014-01-01

Nanoscale structures have been at the core of research efforts dealing with integration of nanotechnology into novel electronic devices for the last decade. Because the size of nanomaterials is of the same order of magnitude as biomolecules, these materials are valuable tools for nanoscale manipulation in a broad range of neurobiological systems. For instance, the unique electrical and optical properties of nanowires, nanotubes, and nanocables with vertical orientation, assembled in nanoscale arrays, have been used in many device applications such as sensors that hold the potential to augment brain functions. However, the challenge in creating nanowires/nanotubes or nanocables array-based sensors lies in making individual electrical connections fitting both the features of the brain and of the nanostructures. This review discusses two of the most important applications of nanostructures in neuroscience. First, the current approaches to create nanowires and nanocable structures are reviewed to critically evaluate their potential for developing unique nanostructure based sensors to improve recording and device performance to reduce noise and the detrimental effect of the interface on the tissue. Second, the implementation of nanomaterials in neurobiological and medical applications will be considered from the brain augmentation perspective. Novel applications for diagnosis and treatment of brain diseases such as multiple sclerosis, meningitis, stroke, epilepsy, Alzheimer's disease, schizophrenia, and autism will be considered. Because the blood brain barrier (BBB) has a defensive mechanism in preventing nanomaterials arrival to the brain, various strategies to help them to pass through the BBB will be discussed. Finally, the implementation of nanomaterials in neurobiological applications is addressed from the brain repair/augmentation perspective. These nanostructures at the interface between nanotechnology and neuroscience will play a pivotal role not only in addressing the multitude of brain disorders but also to repair or augment brain functions. PMID:24999319

Real-time 3D image reconstruction guidance in liver resection surgery.

PubMed

Soler, Luc; Nicolau, Stephane; Pessaux, Patrick; Mutter, Didier; Marescaux, Jacques

2014-04-01

Minimally invasive surgery represents one of the main evolutions of surgical techniques. However, minimally invasive surgery adds difficulty that can be reduced through computer technology. From a patient's medical image [US, computed tomography (CT) or MRI], we have developed an Augmented Reality (AR) system that increases the surgeon's intraoperative vision by providing a virtual transparency of the patient. AR is based on two major processes: 3D modeling and visualization of anatomical or pathological structures appearing in the medical image, and the registration of this visualization onto the real patient. We have thus developed a new online service, named Visible Patient, providing efficient 3D modeling of patients. We have then developed several 3D visualization and surgical planning software tools to combine direct volume rendering and surface rendering. Finally, we have developed two registration techniques, one interactive and one automatic providing intraoperative augmented reality view. From January 2009 to June 2013, 769 clinical cases have been modeled by the Visible Patient service. Moreover, three clinical validations have been realized demonstrating the accuracy of 3D models and their great benefit, potentially increasing surgical eligibility in liver surgery (20% of cases). From these 3D models, more than 50 interactive AR-assisted surgical procedures have been realized illustrating the potential clinical benefit of such assistance to gain safety, but also current limits that automatic augmented reality will overcome. Virtual patient modeling should be mandatory for certain interventions that have now to be defined, such as liver surgery. Augmented reality is clearly the next step of the new surgical instrumentation but remains currently limited due to the complexity of organ deformations during surgery. Intraoperative medical imaging used in new generation of automated augmented reality should solve this issue thanks to the development of Hybrid OR.

Using augmented reality as a clinical support tool to assist combat medics in the treatment of tension pneumothoraces.

PubMed

Wilson, Kenneth L; Doswell, Jayfus T; Fashola, Olatokunbo S; Debeatham, Wayne; Darko, Nii; Walker, Travelyan M; Danner, Omar K; Matthews, Leslie R; Weaver, William L

2013-09-01

This study was to extrapolate potential roles of augmented reality goggles as a clinical support tool assisting in the reduction of preventable causes of death on the battlefield. Our pilot study was designed to improve medic performance in accurately placing a large bore catheter to release tension pneumothorax (prehospital setting) while using augmented reality goggles. Thirty-four preclinical medical students recruited from Morehouse School of Medicine performed needle decompressions on human cadaver models after hearing a brief training lecture on tension pneumothorax management. Clinical vignettes identifying cadavers as having life-threatening tension pneumothoraces as a consequence of improvised explosive device attacks were used. Study group (n = 13) performed needle decompression using augmented reality goggles whereas the control group (n = 21) relied solely on memory from the lecture. The two groups were compared according to their ability to accurately complete the steps required to decompress a tension pneumothorax. The medical students using augmented reality goggle support were able to treat the tension pneumothorax on the human cadaver models more accurately than the students relying on their memory (p < 0.008). Although the augmented reality group required more time to complete the needle decompression intervention (p = 0.0684), this did not reach statistical significance. Reprint & Copyright © 2013 Association of Military Surgeons of the U.S.

[Intraoperative augmented reality visualization. Current state of development and initial experiences with the CamC].

PubMed

Weidert, S; Wang, L; von der Heide, A; Navab, N; Euler, E

2012-03-01

The intraoperative application of augmented reality (AR) has so far mainly taken place in the field of endoscopy. Here, the camera image of the endoscope was augmented by computer graphics derived mostly from preoperative imaging. Due to the complex setup and operation of the devices, they have not yet become part of routine clinical practice. The Camera Augmented Mobile C-arm (CamC) that extends a classic C-arm by a video camera and mirror construction is characterized by its uncomplicated handling. It combines its video live stream geometrically correct with the acquired X-ray. The clinical application of the device in 43 cases showed the strengths of the device in positioning for X-ray acquisition, incision placement, K-wire placement, and instrument guidance. With its new function and the easy integration into the OR workflow of any procedure that requires X-ray imaging, the CamC has the potential to become the first widely used AR technology for orthopedic and trauma surgery.

Likelihood-based methods for evaluating principal surrogacy in augmented vaccine trials.

PubMed

Liu, Wei; Zhang, Bo; Zhang, Hui; Zhang, Zhiwei

2017-04-01

There is growing interest in assessing immune biomarkers, which are quick to measure and potentially predictive of long-term efficacy, as surrogate endpoints in randomized, placebo-controlled vaccine trials. This can be done under a principal stratification approach, with principal strata defined using a subject's potential immune responses to vaccine and placebo (the latter may be assumed to be zero). In this context, principal surrogacy refers to the extent to which vaccine efficacy varies across principal strata. Because a placebo recipient's potential immune response to vaccine is unobserved in a standard vaccine trial, augmented vaccine trials have been proposed to produce the information needed to evaluate principal surrogacy. This article reviews existing methods based on an estimated likelihood and a pseudo-score (PS) and proposes two new methods based on a semiparametric likelihood (SL) and a pseudo-likelihood (PL), for analyzing augmented vaccine trials. Unlike the PS method, the SL method does not require a model for missingness, which can be advantageous when immune response data are missing by happenstance. The SL method is shown to be asymptotically efficient, and it performs similarly to the PS and PL methods in simulation experiments. The PL method appears to have a computational advantage over the PS and SL methods.

Augmented Cognitive Behavioral Therapy for Poststroke Depressive Symptoms: A Randomized Controlled Trial.

PubMed

Kootker, Joyce A; Rasquin, Sascha M C; Lem, Frederik C; van Heugten, Caroline M; Fasotti, Luciano; Geurts, Alexander C H

2017-04-01

To evaluate the effectiveness of individually tailored cognitive behavioral therapy (CBT) for reducing depressive symptoms with or without anxiety poststroke. Multicenter, assessor-blinded, randomized controlled trial. Ambulatory rehabilitation setting. Patients who had a Hospital Anxiety and Depression Scale-depression subscale (HADS-D) score >7 at least 3 months poststroke (N=61). Participants were randomly allocated to either augmented CBT or computerized cognitive training (CCT). The CBT intervention was based on the principles of recognizing, registering, and altering negative thoughts and cognitions. CBT was augmented with goal-directed real-life activity training given by an occupational or movement therapist. HADS-D was the primary outcome, and measures of participation and quality of life were secondary outcomes. Outcome measurements were performed at baseline, immediately posttreatment, and at 4- and 8-month follow-up. Analysis was performed with linear mixed models using group (CBT vs CCT) as the between-subjects factor and time (4 assessments) as the within-subjects factor. Mixed model analyses showed a significant and persistent time effect for HADS-D (mean difference, -4.6; 95% confidence interval, -5.7 to -3.6; P<.001) and for participation and quality of life in both groups. There was no significant group × time effect for any of the outcome measures. Our augmented CBT intervention was not superior to CCT for the treatment of mood disorders after stroke. Future studies should determine whether both interventions are better than natural history. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Adsorptive immobilization of a Pseudomonas strain on solid carriers for augmented decolourization in a chemostat bioreactor.

PubMed

Tse, Siu-Wah; Yu, Jian

2003-08-01

Pseudomonas GM3, a highly efficient strain in cleavage of azo bonds of synthetic dyes under anoxic conditions, was immobilized via adsorption on two types of carriers, porous glass beads and solid PVA particles. The cells were cultivated in a nutrient medium, adsorbed on sterile carriers, stabilized as biofilms in repeated batch cultures, and introduced into a chemostat activated sludge reactor for augmented decolourization. The microbial cells were quickly adsorbed and fixed on the PVA surface, compared to a slow and linear immobilization on the glass surface. The porous structure of glass beads provided shelter for the embedded cells, giving a high biomass loading or thick biofilm (13.3 mg VS ml-1 carrier) in comparison with PVA particles (4.8 mg VS ml-1 carrier), but the mass transfer of substrate in the biofilm became a significant limiting factorin the thicker biofilms (effectiveness factor eta = 0.31). The microbial decolourization rate per volume of carriers was 0.15 and 0.17 mg dye ml-1 of glass beads and PVA particles, respectively. In augmented decomposition of a recalcitrant azo dye (60 mg l-1), the immobilized Pseudomonas cells in porous glass beads gave a stable decolourization efficiency (80-81%), but cells fixed on solid PVA particles showed an initial high colour removal of 90% which then declined to a stable removal efficiency of 81%. In both cases, the colour removal efficiency of the chemostat bioreactor was increased from < 10% by an activated sludge to approximately 80% by the augmented system.

Open and Filled Hole Static Tensile Strength Characterization of Metal Matrix Composite SCS-9/Beta21s.

DTIC Science & Technology

1992-12-01

Augmentation Program (28) state that for filled hole tensile testing of MMCs the tolerance between the pin diameter and hole diameter must not exceed .0254...Acetate replication, metallography, and fractography will be used in conjunction with analytical methods to define the aforementioned material... fractography that this bi-linear response is due to the release of residual stresses and interfacial failures of the off-axis plies and not micro

Frequency-selective augmenting responses by short-term synaptic depression in cat neocortex

PubMed Central

Houweling, Arthur R; Bazhenov, Maxim; Timofeev, Igor; Grenier, François; Steriade, Mircea; Sejnowski, Terrence J

2002-01-01

Thalamic stimulation at frequencies between 5 and 15 Hz elicits incremental or ‘augmenting’ cortical responses. Augmenting responses can also be evoked in cortical slices and isolated cortical slabs in vivo. Here we show that a realistic network model of cortical pyramidal cells and interneurones including short-term plasticity of inhibitory and excitatory synapses replicates the main features of augmenting responses as obtained in isolated slabs in vivo. Repetitive stimulation of synaptic inputs at frequencies around 10 Hz produced postsynaptic potentials that grew in size and carried an increasing number of action potentials resulting from the depression of inhibitory synaptic currents. Frequency selectivity was obtained through the relatively weak depression of inhibitory synapses at low frequencies, and strong depression of excitatory synapses together with activation of a calcium-activated potassium current at high frequencies. This network resonance is a consequence of short-term synaptic plasticity in a network of neurones without intrinsic resonances. These results suggest that short-term plasticity of cortical synapses could shape the dynamics of synchronized oscillations in the brain. PMID:12122156

Augmented reality in medical education?

PubMed

Kamphuis, Carolien; Barsom, Esther; Schijven, Marlies; Christoph, Noor

2014-09-01

Learning in the medical domain is to a large extent workplace learning and involves mastery of complex skills that require performance up to professional standards in the work environment. Since training in this real-life context is not always possible for reasons of safety, costs, or didactics, alternative ways are needed to achieve clinical excellence. Educational technology and more specifically augmented reality (AR) has the potential to offer a highly realistic situated learning experience supportive of complex medical learning and transfer. AR is a technology that adds virtual content to the physical real world, thereby augmenting the perception of reality. Three examples of dedicated AR learning environments for the medical domain are described. Five types of research questions are identified that may guide empirical research into the effects of these learning environments. Up to now, empirical research mainly appears to focus on the development, usability and initial implementation of AR for learning. Limited review results reflect the motivational value of AR, its potential for training psychomotor skills and the capacity to visualize the invisible, possibly leading to enhanced conceptual understanding of complex causality.

Radiation from violently accelerated bodies

NASA Astrophysics Data System (ADS)

Gerlach, Ulrich H.

2001-11-01

A determination is made of the radiation emitted by a linearly uniformly accelerated uncharged dipole transmitter. It is found that, first of all, the radiation rate is given by the familiar Larmor formula, but it is augmented by an amount which becomes dominant for sufficiently high acceleration. For an accelerated dipole oscillator, the criterion is that the center of mass motion become relativistic within one oscillation period. The augmented formula and the measurements which it summarizes presuppose an expanding inertial observation frame. A static inertial reference frame will not do. Secondly, it is found that the radiation measured in the expanding inertial frame is received with 100% fidelity. There is no blueshift or redshift due to the accelerative motion of the transmitter. Finally, it is found that a pair of coherently radiating oscillators accelerating (into opposite directions) in their respective causally disjoint Rindler-coordinatized sectors produces an interference pattern in the expanding inertial frame. Like the pattern of a Young double slit interferometer, this Rindler interferometer pattern has a fringe spacing which is inversely proportional to the proper separation and the proper frequency of the accelerated sources. The interferometer, as well as the augmented Larmor formula, provide a unifying perspective. It joins adjacent Rindler-coordinatized neighborhoods into a single spacetime arena for scattering and radiation from accelerated bodies.

Precise Haptic Device Co-Location for Visuo-Haptic Augmented Reality.

PubMed

Eck, Ulrich; Pankratz, Frieder; Sandor, Christian; Klinker, Gudrun; Laga, Hamid

2015-12-01

Visuo-haptic augmented reality systems enable users to see and touch digital information that is embedded in the real world. PHANToM haptic devices are often employed to provide haptic feedback. Precise co-location of computer-generated graphics and the haptic stylus is necessary to provide a realistic user experience. Previous work has focused on calibration procedures that compensate the non-linear position error caused by inaccuracies in the joint angle sensors. In this article we present a more complete procedure that additionally compensates for errors in the gimbal sensors and improves position calibration. The proposed procedure further includes software-based temporal alignment of sensor data and a method for the estimation of a reference for position calibration, resulting in increased robustness against haptic device initialization and external tracker noise. We designed our procedure to require minimal user input to maximize usability. We conducted an extensive evaluation with two different PHANToMs, two different optical trackers, and a mechanical tracker. Compared to state-of-the-art calibration procedures, our approach significantly improves the co-location of the haptic stylus. This results in higher fidelity visual and haptic augmentations, which are crucial for fine-motor tasks in areas such as medical training simulators, assembly planning tools, or rapid prototyping applications.

ELECTROPHYSIOLOGY OF ELECTRIC ORGAN IN GYMNOTUS CARAPO

PubMed Central

Bennett, Michael V. L.; Grundfest, Harry

1959-01-01

The electric organ of G. carapo is formed by linearly arrayed electroplaques which lie in four tubes on each side of the fish. In one tube the electroplaques are innervated on their rostral surfaces, in the others on the caudal. Both surfaces of each electroplaque produce spikes, and either can be excited alone by a suitably oriented externally applied stimulating current. The innervated surface, however, has a lower threshold, and in the normal organ activity, which is a continuous discharge at 35 to 60/sec., it is always fired first by the large neurally evoked postsynaptic potential. The spike of the innervated face then fires the opposite face. The potential recorded external to the innervated face is initially negative and becomes positive when the other face fires. The potential outside the other face is inverted. The p.s.p.'s are electrically inexcitable, have short duration, and are augmented by hyperpolarization. A single electroplaque is innervated by several nerve fibers, which produce summative p.s.p.'s. Homosynaptic facilitation of p.s.p.'s is common. The synapses are cholinoceptive. The organ discharge begins with synchronized activity in the rostrally innervated electroplaques. After a brief interval, the electroplaques in the other three tubes fire. The organ discharge therefore is triphasic, resulting from the summation of the two diphasic components that are oppositely directed and asynchronous. Observations on the sensory role of the organ are included. PMID:13654750

X-ray photoelectron spectrum and electronic properties of a noncentrosymmetric chalcopyrite compound HgGa(2)S(4): LDA, GGA, and EV-GGA.

PubMed

Reshak, Ali Hussain; Khenata, R; Kityk, I V; Plucinski, K J; Auluck, S

2009-04-30

An all electron full potential linearized augmented plane wave method has been applied for a theoretical study of the band structure, density of states, and electron charge density of a noncentrosymmetric chalcopyrite compound HgGa(2)S(4) using three different approximations for the exchange correlation potential. Our calculations show that the valence band maximum (VBM) and conduction band minimum (CBM) are located at Gamma resulting in a direct energy gap of about 2.0, 2.2, and 2.8 eV for local density approximation (LDA), generalized gradient approximation (GGA), and Engel-Vosko (EVGGA) compared to the experimental value of 2.84 eV. We notice that EVGGA shows excellent agreement with the experimental data. This agreement is attributed to the fact that the Engel-Vosko GGA formalism optimizes the corresponding potential for band structure calculations. We make a detailed comparison of the density of states deduced from the X-ray photoelectron spectra with our calculations. We find that there is a strong covalent bond between the Hg and S atoms and Ga and S atoms. The Hg-Hg, Ga-Ga, and S-S bonds are found to be weaker than the Hg-S and Ga-S bonds showing that a covalent bond exists between Hg and S atoms and Ga and S atoms.

Single-molecule investigation of the interactions between reconstituted planar lipid membranes and an analogue of the HP(2-20) antimicrobial peptide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mereuta, Loredana; Luchian, Tudor; Park, Yoonkyung

2008-09-05

In this study, we employed electrophysiology experiments carried out at the single-molecule level to study the mechanism of action of the HPA3 peptide, an analogue of the linear antimicrobial peptide, HP(2-20), isolated from the N-terminal region of the Helicobacter pylori ribosomal protein. Amplitude analysis of currents fluctuations induced by HPA3 peptide at various potentials in zwitterionic lipid membranes reveal the existence of reproducible conductive states in the stochastic behavior of such events, which directly supports the existence of transmembrane pores induced the peptide. From our data recorded both at the single-pore and macroscopic levels, we propose that the HPA3 poremore » formation is electrophoretically facilitated by trans-negative transmembrane potentials, and HPA3 peptides translocate into the trans monolayers after forming the pores. We present evidence according to which the decrease in the membrane dipole potential of a reconstituted lipid membranes leads to an augmentation of the membrane activity of HPA3 peptides, and propose that a lower electric dipole field of the interfacial region of the membrane caused by phloretin facilitates the surface-bound HPA3 peptides to break free from one leaflet of the membrane, insert into the membrane and contribute to pore formation spanning the entire thickness of the membrane.« less

Effect of pressure variation on structural, elastic, mechanical, optoelectronic and thermodynamic properties of SrNaF3 fluoroperovskite

NASA Astrophysics Data System (ADS)

Erum, Nazia; Azhar Iqbal, Muhammad

2017-12-01

The effect of pressure variation on structural, electronic, elastic, mechanical, optical and thermodynamic characteristics of cubic SrNaF3 fluoroperovskite have been investigated by employing first-principles method within the framework of gradient approximation (GGA). For the total energy calculations, we have used the full-potential linearized augmented plane wave (FP-LAPW) method. Thermodynamic properties are computed in terms of quasi-harmonic Debye model. The pressure effects are determined in the range of 0-25 GPa, in which mechanical stability of SrNaF3 fluoroperovskite remains valid. A prominent decrease in lattice constant and bonds length is observed with the increase in pressure from 0 to 25 GPa. The effect of increase in pressure on band structure calculations with GGA and GGA plus Tran-Blaha modified Becke-Johnson (TB-mBJ) potential reveals a predominant characteristic associated with widening of bandgap. The influence of pressure on set of isotropic elastic parameters and their related properties are numerically estimated for SrNaF3 polycrystalline aggregate. Apart of linear dependence of elastic coefficients, transition from brittle to ductile behavior is observed as pressure is increased from 0 to 25 GPa. We have successfully obtained variation of lattice constant, volume expansion, bulk modulus, Debye temperature and specific heat capacities with pressure and temperature in the range of 0-25 GPa and 0-600 K. All the calculated optical properties such as the complex dielectric function ɛ(ω), optical conductivity σ(ω), energy loss function L(ω), absorption coefficient α(w), refractive index n(ω), reflectivity R(ω), and effective number of electrons n eff, via sum rules shift towards the higher energies under the application of pressure.

Benchmark calculations with correlated molecular wavefunctions. XIII. Potential energy curves for He2, Ne2 and Ar2 using correlation consistent basis sets through augmented sextuple zeta

NASA Astrophysics Data System (ADS)

van Mourik, Tanja

1999-02-01

The potential energy curves of the rare gas dimers He2, Ne2, and Ar2 have been computed using correlation consistent basis sets ranging from singly augmented aug-cc-pVDZ sets through triply augmented t-aug-cc-pV6Z sets, with the augmented sextuple basis sets being reported herein. Several methods for including electron correlation were investigated, namely Moller-Plesset perturbation theory (MP2, MP3 and MP4) and coupled cluster theory [CCSD and CCSD(T)]. For He2CCSD(T)/d-aug-cc-pV6Z calculations yield a well depth of 7.35cm-1 (10.58K), with an estimated complete basis set (CBS) limit of 7.40cm-1 (10.65K). The latter is smaller than the 'exact' well depth (Aziz, R. A., Janzen, A. R., and Moldover, M. R., 1995, Phys. Rev. Lett., 74, 1586) by about 0.2cm-1 (0.35K). The Ne well depth, computed with the CCSD(T)/d-aug-cc-pV6Z method, is 28.31cm-1 and the estimated CBS limit is 28.4cm-1, approximately 1cm-1 smaller than the empirical potential of Aziz, R. A., and Slaman, M., J., 1989, Chem. Phys., 130, 187. Inclusion of core and core-valence correlation effects has a negligible effect on the Ne well depth, decreasing it by only 0.04cm-1. For Ar2, CCSD(T)/ d-aug-cc-pV6Z calculations yield a well depth of 96.2cm-1. The corresponding HFDID potential of Aziz, R. A., 1993, J. chem. Phys., 99, 4518 predicts of D of 99.7cm-1. Inclusion of core and core-valence effects in Ar increases the well depth and decreases the discrepancy by approximately 1cm-1.

Examination of the Pharmacology of Oxytocin and Clinical Guidelines for Use in Labor.

PubMed

Page, Katie; McCool, William F; Guidera, Mamie

2017-07-01

The use of exogenous oxytocin to induce or augment labor has increased in recent years. This literature-informed review examines the action of this medication and the potential associated complications, with an evaluation of current professional practice guidelines. A brief history of the use of exogenous oxytocin for labor induction or augmentation is presented. In addition, risk management strategies for the prevention of oxytocin-related adverse outcomes and subsequent litigation are identified. © 2017 by the American College of Nurse-Midwives.

A way around the Nyquist lag

NASA Astrophysics Data System (ADS)

Penland, C.

2017-12-01

One way to test for the linearity of a multivariate system is to perform Linear Inverse Modeling (LIM) to a multivariate time series. LIM yields an estimated operator by combining a lagged covariance matrix with the contemporaneous covariance matrix. If the underlying dynamics is linear, the resulting dynamical description should not depend on the particular lag at which the lagged covariance matrix is estimated. This test is known as the "tau test." The tau test will be severely compromised if the lag at which the analysis is performed is approximately half the period of an internal oscillation frequency. In this case, the tau test will fail even though the dynamics are actually linear. Thus, until now, the tau test has only been possible for lags smaller than this "Nyquist lag." In this poster, we investigate the use of Hilbert transforms as a way to avoid the problems associated with Nyquist lags. By augmenting the data with dimensions orthogonal to those spanning the original system, information that would be inaccessible to LIM in its original form may be sampled.

Augmenting NMDA receptor signaling boosts experience-dependent neuroplasticity in the adult human brain

PubMed Central

Forsyth, Jennifer K.; Bachman, Peter; Mathalon, Daniel H.; Roach, Brian J.; Asarnow, Robert F.

2015-01-01

Experience-dependent plasticity is a fundamental property of the brain. It is critical for everyday function, is impaired in a range of neurological and psychiatric disorders, and frequently depends on long-term potentiation (LTP). Preclinical studies suggest that augmenting N-methyl-d-aspartate receptor (NMDAR) signaling may promote experience-dependent plasticity; however, a lack of noninvasive methods has limited our ability to test this idea in humans until recently. We examined the effects of enhancing NMDAR signaling using d-cycloserine (DCS) on a recently developed LTP EEG paradigm that uses high-frequency visual stimulation (HFvS) to induce neural potentiation in visual cortex neurons, as well as on three cognitive tasks: a weather prediction task (WPT), an information integration task (IIT), and a n-back task. The WPT and IIT are learning tasks that require practice with feedback to reach optimal performance. The n-back assesses working memory. Healthy adults were randomized to receive DCS (100 mg; n = 32) or placebo (n = 33); groups were similar in IQ and demographic characteristics. Participants who received DCS showed enhanced potentiation of neural responses following repetitive HFvS, as well as enhanced performance on the WPT and IIT. Groups did not differ on the n-back. Augmenting NMDAR signaling using DCS therefore enhanced activity-dependent plasticity in human adults, as demonstrated by lasting enhancement of neural potentiation following repetitive HFvS and accelerated acquisition of two learning tasks. Results highlight the utility of considering cellular mechanisms underlying distinct cognitive functions when investigating potential cognitive enhancers. PMID:26621715

Scaffolds in Tendon Tissue Engineering

PubMed Central

Longo, Umile Giuseppe; Lamberti, Alfredo; Petrillo, Stefano; Maffulli, Nicola; Denaro, Vincenzo

2012-01-01

Tissue engineering techniques using novel scaffold materials offer potential alternatives for managing tendon disorders. Tissue engineering strategies to improve tendon repair healing include the use of scaffolds, growth factors, cell seeding, or a combination of these approaches. Scaffolds have been the most common strategy investigated to date. Available scaffolds for tendon repair include both biological scaffolds, obtained from mammalian tissues, and synthetic scaffolds, manufactured from chemical compounds. Preliminary studies support the idea that scaffolds can provide an alternative for tendon augmentation with an enormous therapeutic potential. However, available data are lacking to allow definitive conclusion on the use of scaffolds for tendon augmentation. We review the current basic science and clinical understanding in the field of scaffolds and tissue engineering for tendon repair. PMID:22190961

Geometry Modeling and Adaptive Control of Air-Breathing Hypersonic Vehicles

NASA Astrophysics Data System (ADS)

Vick, Tyler Joseph

Air-breathing hypersonic vehicles have the potential to provide global reach and affordable access to space. Recent technological advancements have made scramjet-powered flight achievable, as evidenced by the successes of the X-43A and X-51A flight test programs over the last decade. Air-breathing hypersonic vehicles present unique modeling and control challenges in large part due to the fact that scramjet propulsion systems are highly integrated into the airframe, resulting in strongly coupled and often unstable dynamics. Additionally, the extreme flight conditions and inability to test fully integrated vehicle systems larger than X-51 before flight leads to inherent uncertainty in hypersonic flight. This thesis presents a means to design vehicle geometries, simulate vehicle dynamics, and develop and analyze control systems for hypersonic vehicles. First, a software tool for generating three-dimensional watertight vehicle surface meshes from simple design parameters is developed. These surface meshes are compatible with existing vehicle analysis tools, with which databases of aerodynamic and propulsive forces and moments can be constructed. A six-degree-of-freedom nonlinear dynamics simulation model which incorporates this data is presented. Inner-loop longitudinal and lateral control systems are designed and analyzed utilizing the simulation model. The first is an output feedback proportional-integral linear controller designed using linear quadratic regulator techniques. The second is a model reference adaptive controller (MRAC) which augments this baseline linear controller with an adaptive element. The performance and robustness of each controller are analyzed through simulated time responses to angle-of-attack and bank angle commands, while various uncertainties are introduced. The MRAC architecture enables the controller to adapt in a nonlinear fashion to deviations from the desired response, allowing for improved tracking performance, stability, and robustness.

Using augmented reality to teach and learn biochemistry.

PubMed

Vega Garzón, Juan Carlos; Magrini, Marcio Luiz; Galembeck, Eduardo

2017-09-01

Understanding metabolism and metabolic pathways constitutes one of the central aims for students of biological sciences. Learning metabolic pathways should be focused on the understanding of general concepts and core principles. New technologies such Augmented Reality (AR) have shown potential to improve assimilation of biochemistry abstract concepts because students can manipulate 3D molecules in real time. Here we describe an application named Augmented Reality Metabolic Pathways (ARMET), which allowed students to visualize the 3D molecular structure of substrates and products, thus perceiving changes in each molecule. The structural modification of molecules shows students the flow and exchange of compounds and energy through metabolism. © 2017 by The International Union of Biochemistry and Molecular Biology, 45(5):417-420, 2017. © 2017 The International Union of Biochemistry and Molecular Biology.

Adipose-derived stem-cell-implanted poly(ϵ-caprolactone)/chitosan scaffold improves bladder regeneration in a rat model.

PubMed

Zhou, Zhe; Yan, Hao; Liu, Yidong; Xiao, Dongdong; Li, Wei; Wang, Qiong; Zhao, Yang; Sun, Kang; Zhang, Ming; Lu, Mujun

2018-04-01

The study investigated the feasibility of seeding adipose-derived stem cells (ASCs) onto a poly(ϵ-caprolactone)/chitosan (PCL/CS) scaffold for bladder reconstruction using a rat model of bladder augmentation. In the experimental group, the autologous ASCs were seeded onto the PCL/CS scaffold for bladder augmentation. An unseeded scaffold was used for bladder augmentation as control group. The sham group was also set. 8 weeks after implantation, more densely smooth muscles were detected in the experimental group with a larger bladder capacity and more intensive blood vessels. Immunofluorescence staining demonstrated that some of the smooth muscle cells were transdifferentiated from the ASCs. Our findings indicated that ASC-seeded PCL/CS may be a potential scaffold for bladder tissue engineering.

Contingency power for small turboshaft engines using water injection into turbine cooling air

NASA Technical Reports Server (NTRS)

Biesiadny, Thomas J.; Klann, Gary A.; Clark, David A.; Berger, Brett

1987-01-01

Because of one engine inoperative requirements, together with hot-gas reingestion and hot day, high altitude takeoff situations, power augmentation for multiengine rotorcraft has always been of critical interest. However, power augmentation using overtemperature at the turbine inlet will shorten turbine life unless a method of limiting thermal and mechanical stresses is found. A possible solution involves allowing the turbine inlet temperature to rise to augment power while injecting water into the turbine cooling air to limit hot-section metal temperatures. An experimental water injection device was installed in an engine and successfully tested. Although concern for unprotected subcomponents in the engine hot section prevented demonstration of the technique's maximum potential, it was still possible to demonstrate increases in power while maintaining nearly constant turbine rotor blade temperature.

Modular design attitude control system

NASA Technical Reports Server (NTRS)

Chichester, F. D.

1982-01-01

A hybrid multilevel linear quadratic regulator (ML-LQR) approach was developed and applied to the attitude control of models of the rotational dynamics of a prototype flexible spacecraft and of a typical space platform. Three axis rigid body flexible suspension models were developed for both the spacecraft and the space platform utilizing augmented body methods. Models of the spacecraft with hybrid ML-LQR attitude control and with LQR attitude control were simulated and their response with the two different types of control were compared.

Augmented l1 and Nuclear-Norm Models with a Globally Linearly Convergent Algorithm. Revision 1

DTIC Science & Technology

2012-10-17

nonzero and sampled from the standard Gaussian distribution (for Figure 2) or the Bernoulli distribution (for Figure 3). Both tests had the same sensing...dual variable y(k) Figure 3: Convergence of primal and dual variables of three algorithms on Bernoulli sparse x0 was the slowest. Besides the obvious...slower convergence than the final stage. Comparing the results of two tests, the convergence was faster on the Bernoulli sparse signal than the

Generating chaos for discrete time-delayed systems via impulsive control.

PubMed

Guan, Zhi-Hong; Liu, Na

2010-03-01

Generating chaos for a class of discrete time-delayed systems via impulsive control is investigated in this paper. With the augmented matrix method, the time-delay impulsive systems can be transformed into a new class of linear discrete impulsive systems. Based on the largest Lyapunov exponent and the boundedness of the systems, some theoretical results about the chaotification for the discrete impulsive systems with time delay are derived and an example is given to visualize the satisfactory control performance.

Dynamic stability and handling qualities tests on a highly augmented, statically unstable airplane

NASA Technical Reports Server (NTRS)

Gera, Joseph; Bosworth, John T.

1987-01-01

This paper describes some novel flight tests and analysis techniques in the flight dynamics and handling qualities area. These techniques were utilized during the initial flight envelope clearance of the X-29A aircraft and were largely responsible for the completion of the flight controls clearance program without any incidents or significant delays. The resulting open-loop and closed-loop frequency responses and the time history comparison using flight and linear simulation data are discussed.

Computational Analysis of Material Flow During Friction Stir Welding of AA5059 Aluminum Alloys

DTIC Science & Technology

2011-01-01

tool material (AISI H13 tool steel ) is modeled as an isotropic linear-elastic material. Within the analysis, the effects of some of the FSW key process...threads/m; (b) tool 598 material = AISI H13 tool steel ; (c) workpiece material = 599 AA5059; (d) tool rotation speed = 500 rpm; (e) tool travel 600 speed...the strain-hardening term is augmented to take into account for the effect of dynamic recrystallization) while the FSW tool material (AISI H13

Autonomous Control Modes and Optimized Path Guidance for Shipboard Landing in High Sea States

DTIC Science & Technology

2017-04-15

50 0 50 Singular Values Frequency (rad/s) S in g u la r V a lu e s ( d B ) controller . The non -output variables can be estimated by reliable linear...Contract # N00014-14-C-0004 Autonomous Control Modes and Optimized Path Guidance for Shipboard Landing in High Sea States Progress Report...recovery of a VTOL UAV. There is a clear need for additional levels of stability and control augmentation and, ultimately, fully autonomous landing

Analysis and application of a velocity command motor as a reaction mass actuator

NASA Technical Reports Server (NTRS)

Sulla, Jeffrey L.; Juang, Jer-Nan; Horta, Lucas G.

1990-01-01

A commercially available linear stepper motor is applied as a reaction mass (RM) actuator. With the actuator operating in the (RM) relative-velocity command mode, open-loop and closed-loop testing is performed to determine operational limits. With the actuator mounted on a simple beam structure, root strain, RM acceleration, or beam acceleration is used in the feedback loop to augment the structural damping. The RM relative position is also used as feedback to ensure that the RM remains centered.

First-principles calculations of the structural, electronic, optical and thermal properties of the BNxAs1-x alloys

NASA Astrophysics Data System (ADS)

Hamioud, L.; Boumaza, A.; Touam, S.; Meradji, H.; Ghemid, S.; El Haj Hassan, F.; Khenata, R.; Omran, S. Bin

2016-06-01

The present paper aims to study the structural, electronic, optical and thermal properties of the boron nitride (BN) and BAs bulk materials as well as the BNxAs1-x ternary alloys by employing the full-potential-linearised augmented plane wave method within the density functional theory. The structural properties are determined using the Wu-Cohen generalised gradient approximation that is based on the optimisation of the total energy. For band structure calculations, both the Wu-Cohen generalised gradient approximation and the modified Becke-Johnson of the exchange-correlation energy and potential, respectively, are used. We investigated the effect of composition on the lattice constants, bulk modulus and band gap. Deviations of the lattice constants and the bulk modulus from the Vegard's law and the linear concentration dependence, respectively, were observed for the alloys where this result allows us to explain some specific behaviours in the electronic properties of the alloys. For the optical properties, the calculated refractive indices and the optical dielectric constants were found to vary nonlinearly with the N composition. Finally, the thermal effect on some of the macroscopic properties was predicted using the quasi-harmonic Debye model in which the lattice vibrations are taken into account.

AB INITIO STUDY OF THE ELECTRONIC AND MAGNETIC PROPERTIES OF GRAPHENE WITH AND WITHOUT ADSORPTION OF M ATOM (M = C, N, O, F, Cl)

NASA Astrophysics Data System (ADS)

Ismail, Ali I.; Mubarak, A. A.

We present here an ab initio study for the energetic, electronic, magnetic and optical structures of the graphene sheet with and without the adsorption of M atom (M = C, N, O, F, Cl). The calculations are preformed using the full-potential linearized augmented plane wave (FP-LAPW) within the generalized gradient approximation (GGA) to describe the exchange-correlation potential. The calculations show that N prefers the bridge site, while C, O, F and Cl prefer the top site above the graphene sheet. The calculated M-graphene bond length is found to be inversely proportional to the adsorption energy. The hybridization between sp-states of the graphene sheet and M adatom is determined by the analysis of the partial and local density of states (PDOS and TDOS). In case of O and F as adsorbed atoms, graphene sheets show a wide energy band-gap and some significant magnetic moments. The optical properties of the studied sheets are performed in different radiation regions using the real and imaginary parts of the dielectric function. We think that the energetic, electronic, optical and magnetic properties of the M-graphene sheets are governed by two main factors; the number of unpaired valence electrons and the electronegativity of the M atom.

Structural, elastic, electronic, optical and thermoelectric properties of the Zintl-phase Ae3AlAs3 (Ae = Sr, Ba)

NASA Astrophysics Data System (ADS)

Benahmed, A.; Bouhemadou, A.; Alqarni, B.; Guechi, N.; Al-Douri, Y.; Khenata, R.; Bin-Omran, S.

2018-05-01

First-principles calculations were performed to investigate the structural, elastic, electronic, optical and thermoelectric properties of the Zintl-phase Ae3AlAs3 (Ae = Sr, Ba) using two complementary approaches based on density functional theory. The pseudopotential plane-wave method was used to explore the structural and elastic properties whereas the full-potential linearised augmented plane wave approach was used to study the structural, electronic, optical and thermoelectric properties. The calculated structural parameters are in good consistency with the corresponding measured ones. The single-crystal and polycrystalline elastic constants and related properties were examined in details. The electronic properties, including energy band dispersions, density of states and charge-carrier effective masses, were computed using Tran-Blaha modified Becke-Johnson functional for the exchange-correlation potential. It is found that both studied compounds are direct band gap semiconductors. Frequency-dependence of the linear optical functions were predicted for a wide photon energy range up to 15 eV. Charge carrier concentration and temperature dependences of the basic parameters of the thermoelectric properties were explored using the semi-classical Boltzmann transport model. Our calculations unveil that the studied compounds are characterised by a high thermopower for both carriers, especially the p-type conduction is more favourable.

Engel-Vosko GGA calculations of the structural, electronic and optical properties of LiYO2

NASA Astrophysics Data System (ADS)

Muhammad, Nisar; Khan, Afzal; Haidar Khan, Shah; Sajjaj Siraj, Muhammad; Shah, Syed Sarmad Ali; Murtaza, Ghulam

2017-09-01

Structural, electronic and optical properties of lithium yttrium oxide (LiYO2) are investigated using density functional theory (DFT). These calculations are based on full potential linearized augmented plane wave (FP-LAPW) method implemented by WIEN2k. The generalized gradient approximation (GGA) is used as an exchange correlation potential with Perdew-Burk-Ernzerhof (PBE) and Engel-Vosko (EV) as exchange correlation functional. The structural properties are calculated with PBE-GGA as it gives the equilibrium lattice constants very close to the experimental values. While, the band structure and optical properties are calculated with EV-GGA obtain much closer results to their experimental values. Our calculations confirm LiYO2 as large indirect band gap semiconductor having band gap of 5.23 eV exhibiting the characteristics of ultrawide band gap materials showing the properties like higher critical breakdown field, higher temperature operation and higher radiation tolerance. In this article, we report the density of states (DOS) in terms of contribution from s, p, and d-states of the constituent atoms, the band structure, the electronic structure, and the frequency-dependent optical properties of LiYO2. The optical properties presented in this article reveal LiYO2 a suitable candidate for the field of optoelectronic and optical devices.

Phonon renormalization and anharmonicity in Al-doped MgB2

NASA Astrophysics Data System (ADS)

Ortiz, Filiberto; Aguayo, Aarón

2005-03-01

We have studied the evolution of the E2g phonon mode dynamics in Mg1-xAlxB2 as a function of doping using the Frozen Phonon Approximation (FPA). The doping was modeled in the ab-initio Virtual Crystal Approximation (VCA). The results were obtained by means of first-principles total-energy calculations using the full potential Linearized Augmented Plane Wave (LAPW) method and the Generalized Gradient Approximation (GGA) for the exchange-correlation potential. We present results for the evolution of the phonon frequency and anharmonicity of the E2g mode as a function of Al concentration (x). From a comparison of the experimental data with the calculated E2g phonon frequency we show that the VCA-FPA reproduces the observed phonon renormalization in the whole range of Al concentrations. More interestingly, we find that the anharmonicity gradually decreases with Al doping and vanishes for x(Al)>0.5, that behaviour correlates with the evolution of the measured Raman linewidth in Al-doped MgB2. The significance of these results are discussed in the light of the experimentally observed loss of superconductivity in Mg1- xAlxB2.This work was supported by Consejo Nacional de Ciencia y Tecnolog'ia (CONACYT, M'exico) under Grant. No. 43830-F.

Growth/differentiation factor-5: pre-clinical and clinical evaluations of periodontal regeneration and alveolar augmentation--review.

PubMed

Lee, Jaebum; Wikesjö, Ulf M E

2014-08-01

Growth/differentiation factor-5 (GDF-5) plays critical roles in mesenchymal cell differentiation and stimulates human periodontal ligament cell proliferation. Potentially, GDF-5 may also play roles in wound healing including periodontal regeneration and alveolar augmentation. The objective of this review was to provide up-to-date information from pre-clinical/clinical studies evaluating GDF-5 for these indications. A comprehensive search using PubMed and Google search engines was conducted to identify reports on GDF-5 applied to periodontal and alveolar indications. Two reviewers independently screened the titles and abstracts from a total of 479 reports. Full-length articles of 17 pre-clinical and four clinical studies were selected and reviewed. Canine-, porcine- and non-human primate-based models as well as human clinical trials were used in the evaluation of GDF-5 in support of periodontal regeneration and alveolar augmentation. An absorbable collagen sponge (ACS), β-tricalcium phosphate (β-TCP) and a poly(lactic-co-glycolic) acid (PLGA) were evaluated as candidate carriers for GDF-5 using various dose and healing intervals demonstrating significantly enhanced periodontal regeneration/alveolar augmentation including cementum, periodontal ligament and alveolar bone with limited, if any, adverse effects. Growth/differentiation factor-5 supports periodontal regeneration/alveolar augmentation without aberrant healing events documented in qualified pre-clinical models and clinical pilot studies. In perspective, GDF-5 appears a promising technology for periodontal regeneration/alveolar augmentation. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Into the Wild: Neuroergonomic Differentiation of Hand-Held and Augmented Reality Wearable Displays during Outdoor Navigation with Functional Near Infrared Spectroscopy.

PubMed

McKendrick, Ryan; Parasuraman, Raja; Murtza, Rabia; Formwalt, Alice; Baccus, Wendy; Paczynski, Martin; Ayaz, Hasan

2016-01-01

Highly mobile computing devices promise to improve quality of life, productivity, and performance. Increased situation awareness and reduced mental workload are two potential means by which this can be accomplished. However, it is difficult to measure these concepts in the "wild". We employed ultra-portable battery operated and wireless functional near infrared spectroscopy (fNIRS) to non-invasively measure hemodynamic changes in the brain's Prefrontal cortex (PFC). Measurements were taken during navigation of a college campus with either a hand-held display, or an Augmented reality wearable display (ARWD). Hemodynamic measures were also paired with secondary tasks of visual perception and auditory working memory to provide behavioral assessment of situation awareness and mental workload. Navigating with an augmented reality wearable display produced the least workload during the auditory working memory task, and a trend for improved situation awareness in our measures of prefrontal hemodynamics. The hemodynamics associated with errors were also different between the two devices. Errors with an augmented reality wearable display were associated with increased prefrontal activity and the opposite was observed for the hand-held display. This suggests that the cognitive mechanisms underlying errors between the two devices differ. These findings show fNIRS is a valuable tool for assessing new technology in ecologically valid settings and that ARWDs offer benefits with regards to mental workload while navigating, and potentially superior situation awareness with improved display design.

Into the Wild: Neuroergonomic Differentiation of Hand-Held and Augmented Reality Wearable Displays during Outdoor Navigation with Functional Near Infrared Spectroscopy

PubMed Central

McKendrick, Ryan; Parasuraman, Raja; Murtza, Rabia; Formwalt, Alice; Baccus, Wendy; Paczynski, Martin; Ayaz, Hasan

2016-01-01

Highly mobile computing devices promise to improve quality of life, productivity, and performance. Increased situation awareness and reduced mental workload are two potential means by which this can be accomplished. However, it is difficult to measure these concepts in the “wild”. We employed ultra-portable battery operated and wireless functional near infrared spectroscopy (fNIRS) to non-invasively measure hemodynamic changes in the brain’s Prefrontal cortex (PFC). Measurements were taken during navigation of a college campus with either a hand-held display, or an Augmented reality wearable display (ARWD). Hemodynamic measures were also paired with secondary tasks of visual perception and auditory working memory to provide behavioral assessment of situation awareness and mental workload. Navigating with an augmented reality wearable display produced the least workload during the auditory working memory task, and a trend for improved situation awareness in our measures of prefrontal hemodynamics. The hemodynamics associated with errors were also different between the two devices. Errors with an augmented reality wearable display were associated with increased prefrontal activity and the opposite was observed for the hand-held display. This suggests that the cognitive mechanisms underlying errors between the two devices differ. These findings show fNIRS is a valuable tool for assessing new technology in ecologically valid settings and that ARWDs offer benefits with regards to mental workload while navigating, and potentially superior situation awareness with improved display design. PMID:27242480

Augmentative and alternative communication supports for adults with autism spectrum disorders.

PubMed

Trembath, David; Iacono, Teresa; Lyon, Katie; West, Denise; Johnson, Hilary

2014-11-01

Many adults with autism spectrum disorders have complex communication needs and may benefit from the use of augmentative and alternative communication. However, there is a lack of research examining the specific communication needs of these adults, let alone the outcomes of interventions aimed at addressing them. The aim of this study was to explore the views and experiences of support workers and family members regarding the outcomes of providing low-technology communication aids to adults with autism spectrum disorders. The participants were six support workers and two family members of six men and women with autism spectrum disorders, who had received low-technology communication aids. Using semi-structured, in-depth interviews and following thematic analysis, the results revealed strong support for, and the potential benefits of, augmentative and alternative communication for both adults with autism spectrum disorders and their communication partners. The results also revealed inconsistencies in the actions taken to support the use of the prescribed augmentative and alternative communication systems, pointing to the clinical need to address common barriers to the provision of augmentative and alternative communication support. These barriers include organisational practices and limitations in the knowledge and skills of key stakeholders, as well as problematic attitudes. © The Author(s) 2013.

Motivational factors and psychological processes in cosmetic breast augmentation surgery.

PubMed

Solvi, Anette S; Foss, Kaja; von Soest, Tilmann; Roald, Helge E; Skolleborg, Knut C; Holte, Arne

2010-04-01

We investigated how and why prospective cosmetic breast augmentation patients decide to undergo such surgery. The results can offer important insights to plastic surgeons in addressing their patients' motives and expectations, and thereby avoiding potential patient dissatisfaction and disappointment. It is also a necessary first step to better understand the increasing tendency among women in the Western society to seek cosmetic breast augmentation. A qualitative, descriptive and phenomenological design was employed. Fourteen female prospective breast augmentation patients, aged 19-46 years, were recruited from a private plastic surgery clinic and interviewed in depth based on an informant-centred format. The interviews were tape-recorded, transcribed verbatim and coded and analysed phenomenologically using a QSR-N*Vivo software program. We detected four psychological processes associated with cosmetic breast augmentation surgery (create, improve, repair and restore). The data could further be categorised into one basic drive (femininity), six generating factors (appearance dissatisfaction, ideal figure, self-esteem, comments, clothes and sexuality) and five eliciting factors motivating the decision (media, knowledge of former patients, physicians, finances and romantic partner). These new insights into how and why women seek cosmetic breast augmentation may aid plastic surgeons in enhancing their communication with patients. This can be achieved by addressing the patient's psychological process and motives, and thereby better assist them in making the best decision possible in their particular situation. It may also lay the groundwork for future quantitative studies on the prevalence of certain motives for undergoing such surgery and, as such, help explain the increasing popularity of cosmetic breast-augmentation surgery. Copyright 2009 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Interventions for Dental Implant Placement in Atrophic Edentulous Mandibles: Vertical Bone Augmentation and Alternative Treatments. A Meta-Analysis of Randomized Clinical Trials.

PubMed

Camps-Font, Octavi; Burgueño-Barris, Genís; Figueiredo, Rui; Jung, Ronald E; Gay-Escoda, Cosme; Valmaseda-Castellón, Eduard

2016-12-01

The purpose of the current study is to assess which vertical bone augmentation techniques are most effective for restoring atrophic posterior areas of the mandible with dental implants and compare these procedures with alternative treatments. Electronic literature searches in PubMed (MEDLINE), Ovid, and the Cochrane Library were conducted to identify all relevant articles published up to July 1, 2015. Eligibility was based on inclusion criteria, and quality assessments were conducted. The primary outcome variables were implant and prosthetic failure. After data extraction, meta-analyses were performed. Out of 527 potentially eligible papers, 14 randomized clinical trials were included. Out of these 14 studies, four trials assessed short implants (5 to 8 mm) as an alternative to vertical bone augmentation in sites with a residual ridge height of 5 to 8 mm. No statistically significant differences were found in implant (odds ratio [OR]: 1.02; 95% confidence interval [CI]: 0.31 to 3.31; P = 0.98; I 2 : 0%) or prosthetic failure (OR: 0.64; 95% CI: 0.21 to 1.96; P = 0.43; I 2 : 0%) after 12 months of loading. However, complications at treated sites increased with the augmentation procedures (OR: 8.33; 95% CI: 3.85 to 20.0; P <0.001; I 2 : 0%). There was no evidence of any vertical augmentation procedure being of greater benefit than any other for the primary outcomes (implant and prosthetic failure). Short implants in the posterior area of the mandible seem to be preferable to vertical augmentation procedures, which present similar implant and prosthetic failure rates but greater morbidity. All the vertical augmentation technique comparisons showed similar intergroup results.

A kernel adaptive algorithm for quaternion-valued inputs.

PubMed

Paul, Thomas K; Ogunfunmi, Tokunbo

2015-10-01

The use of quaternion data can provide benefit in applications like robotics and image recognition, and particularly for performing transforms in 3-D space. Here, we describe a kernel adaptive algorithm for quaternions. A least mean square (LMS)-based method was used, resulting in the derivation of the quaternion kernel LMS (Quat-KLMS) algorithm. Deriving this algorithm required describing the idea of a quaternion reproducing kernel Hilbert space (RKHS), as well as kernel functions suitable with quaternions. A modified HR calculus for Hilbert spaces was used to find the gradient of cost functions defined on a quaternion RKHS. In addition, the use of widely linear (or augmented) filtering is proposed to improve performance. The benefit of the Quat-KLMS and widely linear forms in learning nonlinear transformations of quaternion data are illustrated with simulations.

Bone physiology in human grafted and non-grafted extraction sockets--an immunohistochemical study.

PubMed

Nahles, Susanne; Nack, Claudia; Gratecap, Kerrin; Lage, Hermann; Nelson, John J; Nelson, Katja

2013-07-01

The aim of the present immunohistological investigation was to define and compare the osteogenic potential with the vascularization of the provisional matrix in grafted and ungrafted extraction sockets after 4 and 12 weeks of healing. A total of 33 Patients (15 women, 18 men) with 65 extraction sites with a mean age of 54.4 years (30-73 years) participated in this study. After tooth extraction, the sockets were augmented with Bio-Oss collagen or non-augmented. At implant placement after 4 or 12 weeks bone biopsies were obtained. Within the specimens the osteogenic and endothelial potential of mesenchymal cells was analyzed in the provisional matrix using immunohistochemical analysis with three monoclonal antibodies Cbfa1/Runx2, Osteocalcin (OC), and CD31. Statistical analysis was performed using Mann-Whitney U-test, Spearman's rank-order correlation coefficient, and the two-factorial analysis for repeated measurements. Of the 65 extraction sockets, 25 (13 non-augmented, 12 augmented) sites after 4 weeks healing time and 40 (19 non-augmented, 21 augmented) sites after 12 weeks healing time were involved in the study. No signs of acute or chronic inflammation were noted in any specimens. After 4 weeks, a median amount of 56% (10-85%) of Cbfa1 positive cells and a median amount of cells expressing OC of 21% (5-42%) were measured. A median CD31 score of 5 was observed. After 12 weeks, a median amount of 61% (19-90%) positive cells expressed by Cbfa1/Runx2 staining a median amount of OC positive cells of 9% (2-17%) was measured. The results at 12 weeks revealed a median score of CD31 positive cells of 3. Osteoblastic activity in the provisional matrix was highest after 4 weeks of healing period. The active zone of bone formation is found in the apical region of the extraction socket during the early healing phase, shifting to the coronal region after 12 weeks. A peak of osteoblast activity within the first weeks is followed by a reduction in mature osteoblasts with osteoblasts remaining in an inactive stage. The vascularity changed in likewise fashion to the maturation of osteoblasts within the observation period. The results have shown that with increasing age a decreasing endothelial potential was observed not after 4 weeks, but after 12 weeks, thus it suggests that angiogenesis is diminished in older patients in the later phase of healing in extraction sockets. © 2012 John Wiley & Sons A/S.

Hard and soft tissue augmentation in a postorthodontic patient: a case report.

PubMed

Bonacci, Fred J

2011-02-01

A combination of hard and soft tissue grafting is used to augment a thin biotype. A 26-year-old woman with mandibular anterior flaring and Miller Class I and III recessions requested interceptive treatment. Surgery included a full-thickness buccal flap, intramarrow penetrations, bone graft placement, and primary flap closure. Postoperative visits were at 2 and 4 weeks and 2, 3, and 6 months. Stage-two surgery consisted of submerged connective tissue graft placement. Postoperative visits were completed at 2, 4, 6, and 8 weeks and 1 year. Follow-up was completed 3 years after the initial surgery. Interradicular concavities were resolved and gingival biotype was augmented. Soft tissue recession remained at 6 months. Reentry revealed clinical labial plate augmentation; 2 mm was achieved at the lateral incisors and the left central incisor and 3 mm was achieved at the right canine. No bone augmentation was achieved on the left canine and right central incisor. The dehiscence at the right central incisor appeared narrower. Overall, a 2- to 3-mm gain in alveolar bone thickness/height was observed. Two months after stage-two surgery, near complete root coverage was achieved; 1 mm of recession remained on the left central incisor. There was a soft tissue thickness gain of 2 mm without any visual difference in keratinized tissue height. Interradicular concavities were eliminated; the soft tissue was augmented and the gingival biotype was altered. Interdental soft tissue craters remained. One year after connective tissue graft placement, there was near complete root coverage at the left central incisor, which at 2 months experienced residual recession. Interradicular concavities and interdental soft tissue craters were eliminated with soft tissue augmentation, including clinical reestablishment of the mucogingival junction. Clinical stability remained 3 years after the initial surgery, with the patient noting comfort during mastication and routine oral hygiene. A clinical increase in labial plate thickness, in conjunction with soft tissue augmentation, appears to provide for continued stability and decreased potential for future clinical attachment loss.

Cement augmentation of the Proximal Femoral Nail Antirotation (PFNA) - A multicentre randomized controlled trial.

PubMed

Kammerlander, Christian; Hem, Einar S; Klopfer, Tim; Gebhard, Florian; Sermon, An; Dietrich, Michael; Bach, Olaf; Weil, Yoram; Babst, Reto; Blauth, Michael

2018-04-22

New implant designs like the Proximal Femoral Nail Antirotation (PFNA) were developed to reduce failure rates in unstable pertrochanteric fractures in the elderly. Standardized implant augmentation with up to 6 mL of polymethylmethacrylate (PMMA) cement has been introduced to enhance implant anchorage by increasing the implant-bone interface in osteoporotic bone conditions. Biomechanically, loads to failure were significantly higher with augmentation. The primary objective of this study was to compare the mobility of patients with closed unstable trochanteric fractures treated by PFNA either with or without cement augmentation. A prospective multicentre, randomized, patient-blinded trial was conducted with ambulatory patients aged 75 or older who sustained a closed, unstable trochanteric fracture. Surgical fixation had to be performed within 72 h after admission. Outcomes were evaluated at baseline, during surgery, 3 to 14 days after surgery, 3 months, 6 months, and 12 months after surgery. To evaluate the primary objective, patients' walking speed was assessed by the Timed Up and Go (TUG) test. Secondary objectives included the analysis of implant migration assessed on radiographs, quality of life measured by the Barthel Index, mobility measured by the Parker Mobility Score, and complications. Of 253 randomized patients, 223 patients were eligible: 105 patients were allocated to the PFNA Augmentation group and 118 to PFNA group. At 3 to 14 days after surgery, there was no statistical significant difference in mean walking speed between the treatment groups. For the secondary objectives, also no statistical significant differences were found. However, no patient in the PFNA Augmentation group had a reoperation due to mechanical failure or symptomatic implant migration compared to 6 patients in the PFNA group. Augmentation of the PFNA blade did not improve patients' walking ability compared to the use of a non-augmented PFNA but might have the potential to prevent reoperations by strengthening the osteosynthesis construct. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Flexible Modes Control Using Sliding Mode Observers: Application to Ares I

NASA Technical Reports Server (NTRS)

Shtessel, Yuri B.; Hall, Charles E.; Baev, Simon; Orr, Jeb S.

2010-01-01

The launch vehicle dynamics affected by bending and sloshing modes are considered. Attitude measurement data that are corrupted by flexible modes could yield instability of the vehicle dynamics. Flexible body and sloshing modes are reconstructed by sliding mode observers. The resultant estimates are used to remove the undesirable dynamics from the measurements, and the direct effects of sloshing and bending modes on the launch vehicle are compensated by means of a controller that is designed without taking the bending and sloshing modes into account. A linearized mathematical model of Ares I launch vehicle was derived based on FRACTAL, a linear model developed by NASA/MSFC. The compensated vehicle dynamics with a simple PID controller were studied for the launch vehicle model that included two bending modes, two slosh modes and actuator dynamics. A simulation study demonstrated stable and accurate performance of the flight control system with the augmented simple PID controller without the use of traditional linear bending filters.

Do pain-associated contexts increase pain sensitivity? An investigation using virtual reality.

PubMed

Harvie, Daniel S; Sterling, Michele; Smith, Ashley D

2018-04-30

Pain is not a linear result of nociception, but is dependent on multisensory inputs, psychological factors, and prior experience. Since nociceptive models appear insufficient to explain chronic pain, understanding non-nociceptive contributors is imperative. Several recent models propose that cues associatively linked to painful events might acquire the capacity to augment, or even cause, pain. This experiment aimed to determine whether contexts associated with pain, could modulate mechanical pain thresholds and pain intensity. Forty-eight healthy participants underwent a contextual conditioning procedure, where three neutral virtual reality contexts were paired with either unpredictable noxious stimulation, unpredictable vibrotactile stimulation, or no stimulation. Following the conditioning procedure, mechanical pain thresholds and pain evoked by a test stimulus were examined in each context. In the test phase, the effect of expectancy was equalised across conditions by informing participants when thresholds and painful stimuli would be presented. Contrary to our hypothesis, scenes that were associated with noxious stimulation did not increase mechanical sensitivity (p=0.08), or increase pain intensity (p=0.46). However, an interaction with sex highlighted the possibility that pain-associated contexts may alter pain sensitivity in females but not males (p=0.03). Overall, our data does not support the idea that pain-associated contexts can alter pain sensitivity in healthy asymptomatic individuals. That an effect was shown in females highlights the possibility that some subgroups may be susceptible to such an effect, although the magnitude of the effect may lack real-world significance. If pain-associated cues prove to have a relevant pain augmenting effect, in some subgroups, procedures aimed at extinguishing pain-related associations may have therapeutic potential.

Alterations in Neural Control of Constant Isometric Contraction with the Size of Error Feedback

PubMed Central

Hwang, Ing-Shiou; Lin, Yen-Ting; Huang, Wei-Min; Yang, Zong-Ru; Hu, Chia-Ling; Chen, Yi-Ching

2017-01-01

Discharge patterns from a population of motor units (MUs) were estimated with multi-channel surface electromyogram and signal processing techniques to investigate parametric differences in low-frequency force fluctuations, MU discharges, and force-discharge relation during static force-tracking with varying sizes of execution error presented via visual feedback. Fourteen healthy adults produced isometric force at 10% of maximal voluntary contraction through index abduction under three visual conditions that scaled execution errors with different amplification factors. Error-augmentation feedback that used a high amplification factor (HAF) to potentiate visualized error size resulted in higher sample entropy, mean frequency, ratio of high-frequency components, and spectral dispersion of force fluctuations than those of error-reducing feedback using a low amplification factor (LAF). In the HAF condition, MUs with relatively high recruitment thresholds in the dorsal interosseous muscle exhibited a larger coefficient of variation for inter-spike intervals and a greater spectral peak of the pooled MU coherence at 13–35 Hz than did those in the LAF condition. Manipulation of the size of error feedback altered the force-discharge relation, which was characterized with non-linear approaches such as mutual information and cross sample entropy. The association of force fluctuations and global discharge trace decreased with increasing error amplification factor. Our findings provide direct neurophysiological evidence that favors motor training using error-augmentation feedback. Amplification of the visualized error size of visual feedback could enrich force gradation strategies during static force-tracking, pertaining to selective increases in the discharge variability of higher-threshold MUs that receive greater common oscillatory inputs in the β-band. PMID:28125658

Stochastic parameter estimation in nonlinear time-delayed vibratory systems with distributed delay

NASA Astrophysics Data System (ADS)

Torkamani, Shahab; Butcher, Eric A.

2013-07-01

The stochastic estimation of parameters and states in linear and nonlinear time-delayed vibratory systems with distributed delay is explored. The approach consists of first employing a continuous time approximation to approximate the delayed integro-differential system with a large set of ordinary differential equations having stochastic excitations. Then the problem of state and parameter estimation in the resulting stochastic ordinary differential system is represented as an optimal filtering problem using a state augmentation technique. By adapting the extended Kalman-Bucy filter to the augmented filtering problem, the unknown parameters of the time-delayed system are estimated from noise-corrupted, possibly incomplete measurements of the states. Similarly, the upper bound of the distributed delay can also be estimated by the proposed technique. As an illustrative example to a practical problem in vibrations, the parameter, delay upper bound, and state estimation from noise-corrupted measurements in a distributed force model widely used for modeling machine tool vibrations in the turning operation is investigated.

Control Augmented Structural Synthesis

NASA Technical Reports Server (NTRS)

Lust, Robert V.; Schmit, Lucien A.

1988-01-01

A methodology for control augmented structural synthesis is proposed for a class of structures which can be modeled as an assemblage of frame and/or truss elements. It is assumed that both the plant (structure) and the active control system dynamics can be adequately represented with a linear model. The structural sizing variables, active control system feedback gains and nonstructural lumped masses are treated simultaneously as independent design variables. Design constraints are imposed on static and dynamic displacements, static stresses, actuator forces and natural frequencies to ensure acceptable system behavior. Multiple static and dynamic loading conditions are considered. Side constraints imposed on the design variables protect against the generation of unrealizable designs. While the proposed approach is fundamentally more general, here the methodology is developed and demonstrated for the case where: (1) the dynamic loading is harmonic and thus the steady state response is of primary interest; (2) direct output feedback is used for the control system model; and (3) the actuators and sensors are collocated.

CSI, optimal control, and accelerometers: Trials and tribulations

NASA Technical Reports Server (NTRS)

Benjamin, Brian J.; Sesak, John R.

1994-01-01

New results concerning optimal design with accelerometers are presented. These results show that the designer must be concerned with the stability properties of two Linear Quadratic Gaussian (LQG) compensators, one of which does not explicitly appear in the closed-loop system dynamics. The new concepts of virtual and implemented compensators are introduced to cope with these subtleties. The virtual compensator appears in the closed-loop system dynamics and the implemented compensator appears in control electronics. The stability of one compensator does not guarantee the stability of the other. For strongly stable (robust) systems, both compensators should be stable. The presence of controlled and uncontrolled modes in the system results in two additional forms of the compensator with corresponding terms that are of like form, but opposite sign, making simultaneous stabilization of both the virtual and implemented compensator difficult. A new design algorithm termed sensor augmentation is developed that aids stabilization of these compensator forms by incorporating a static augmentation term associated with the uncontrolled modes in the design process.

A comparison of linear respiratory system models based on parameter estimates from PRN forced oscillation data.

PubMed

Diong, B; Grainger, J; Goldman, M; Nazeran, H

2009-01-01

The forced oscillation technique offers some advantages over spirometry for assessing pulmonary function. It requires only passive patient cooperation; it also provides data in a form, frequency-dependent impedance, which is very amenable to engineering analysis. In particular, the data can be used to obtain parameter estimates for electric circuit-based models of the respiratory system, which can in turn aid the detection and diagnosis of various diseases/pathologies. In this study, we compare the least-squares error performance of the RIC, extended RIC, augmented RIC, augmented RIC+I(p), DuBois, Nagels and Mead models in fitting 3 sets of impedance data. These data were obtained by pseudorandom noise forced oscillation of healthy subjects, mild asthmatics and more severe asthmatics. We found that the aRIC+I(p) and DuBois models yielded the lowest fitting errors (for the healthy subjects group and the 2 asthmatic patient groups, respectively) without also producing unphysiologically large component estimates.

A triaxial accelerometer-based physical-activity recognition via augmented-signal features and a hierarchical recognizer.

PubMed

Khan, Adil Mehmood; Lee, Young-Koo; Lee, Sungyoung Y; Kim, Tae-Seong

2010-09-01

Physical-activity recognition via wearable sensors can provide valuable information regarding an individual's degree of functional ability and lifestyle. In this paper, we present an accelerometer sensor-based approach for human-activity recognition. Our proposed recognition method uses a hierarchical scheme. At the lower level, the state to which an activity belongs, i.e., static, transition, or dynamic, is recognized by means of statistical signal features and artificial-neural nets (ANNs). The upper level recognition uses the autoregressive (AR) modeling of the acceleration signals, thus, incorporating the derived AR-coefficients along with the signal-magnitude area and tilt angle to form an augmented-feature vector. The resulting feature vector is further processed by the linear-discriminant analysis and ANNs to recognize a particular human activity. Our proposed activity-recognition method recognizes three states and 15 activities with an average accuracy of 97.9% using only a single triaxial accelerometer attached to the subject's chest.

An analysis of region-of-influence methods for flood regionalization in the Gulf-Atlantic Rolling Plains

USGS Publications Warehouse

Eng, K.; Tasker, Gary D.; Milly, P.C.D.

2005-01-01

Region-of-influence (RoI) approaches for estimating streamflow characteristics at ungaged sites were applied and evaluated in a case study of the 50-year peak discharge in the Gulf-Atlantic Rolling Plains of the southeastern United States. Linear regression against basin characteristics was performed for each ungaged site considered based on data from a region of influence containing the n closest gages in predictor variable (PRoI) or geographic (GRoI) space. Augmentation of this count based cutoff by a distance based cutoff also was considered. Prediction errors were evaluated for an independent (split-sampled) dataset. For the dataset and metrics considered here: (1) for either PRoI or GRoI, optimal results were found when the simpler count based cutoff, rather than the distance augmented cutoff, was used; (2) GRoI produced lower error than PRoI when applied indiscriminately over the entire study region; (3) PRoI performance improved considerably when RoI was restricted to predefined geographic subregions.

Geospatial Augmented Reality for the interactive exploitation of large-scale walkable orthoimage maps in museums

NASA Astrophysics Data System (ADS)

Wüest, Robert; Nebiker, Stephan

2018-05-01

In this paper we present an app framework for augmenting large-scale walkable maps and orthoimages in museums or public spaces using standard smartphones and tablets. We first introduce a novel approach for using huge orthoimage mosaic floor prints covering several hundred square meters as natural Augmented Reality (AR) markers. We then present a new app architecture and subsequent tests in the Swissarena of the Swiss National Transport Museum in Lucerne demonstrating the capabilities of accurately tracking and augmenting different map topics, including dynamic 3d data such as live air traffic. The resulting prototype was tested with everyday visitors of the museum to get feedback on the usability of the AR app and to identify pitfalls when using AR in the context of a potentially crowded museum. The prototype is to be rolled out to the public after successful testing and optimization of the app. We were able to show that AR apps on standard smartphone devices can dramatically enhance the interactive use of large-scale maps for different purposes such as education or serious gaming in a museum context.

A Simple Model of Pulsed Ejector Thrust Augmentation

NASA Technical Reports Server (NTRS)

Wilson, Jack; Deloof, Richard L. (Technical Monitor)

2003-01-01

A simple model of thrust augmentation from a pulsed source is described. In the model it is assumed that the flow into the ejector is quasi-steady, and can be calculated using potential flow techniques. The velocity of the flow is related to the speed of the starting vortex ring formed by the jet. The vortex ring properties are obtained from the slug model, knowing the jet diameter, speed and slug length. The model, when combined with experimental results, predicts an optimum ejector radius for thrust augmentation. Data on pulsed ejector performance for comparison with the model was obtained using a shrouded Hartmann-Sprenger tube as the pulsed jet source. A statistical experiment, in which ejector length, diameter, and nose radius were independent parameters, was performed at four different frequencies. These frequencies corresponded to four different slug length to diameter ratios, two below cut-off, and two above. Comparison of the model with the experimental data showed reasonable agreement. Maximum pulsed thrust augmentation is shown to occur for a pulsed source with slug length to diameter ratio equal to the cut-off value.

Augmentation treatment in major depressive disorder: focus on aripiprazole

PubMed Central

Nelson, J Craig; Pikalov, Andrei; Berman, Robert M

2008-01-01

Major depressive disorder (MDD) is a disabling psychiatric condition for which effective treatment remains an outstanding need. Antidepressants are currently the mainstay of treatment for depression; however, almost two-thirds of patients will fail to achieve remission with initial treatment. As a result, a range of augmentation and combination strategies have been used in order to improve outcomes for patients. Despite the popularity of these approaches, limited data from double-blind, randomized, placebo-controlled studies are available to allow clinicians to determine which are the most effective augmentation options or which patients are most likely to respond to which options. Recently, evidence has shown that adjunctive therapy with atypical antipsychotics has the potential for beneficial antidepressant effects in the absence of psychotic symptoms. In particular, aripiprazole has shown efficacy as an augmentation option with standard antidepressant therapy in two, large, randomized, double-blind studies. Based on these efficacy and safety data, aripiprazole was recently approved by the FDA as adjunctive therapy for MDD. The availability of this new treatment option should allow more patients with MDD to achieve remission and, ultimately, long-term, successful outcomes. PMID:19183784

Predictive value of ridge dimensions on autologous bone graft resorption in staged maxillary sinus augmentation surgery using Cone-Beam CT.

PubMed

Klijn, R J; van den Beucken, J J J P; Bronkhorst, E M; Berge, S J; Meijer, G J; Jansen, J A

2012-04-01

No studies are available that provide predictive parameters regarding the expected amount of resorption after maxillary sinus augmentation surgery using autologous bone grafts. Therefore, the aim of this study was to determine parameters influencing the outcome of the bone graft resorption process. In 20 patients, three-dimensional analysis of alveolar ridge dimensions and bone graft volume change in the atrophic posterior maxilla was performed by Cone-Beam Computerized Tomography imaging. Ridge dimensions were assessed before maxillary sinus augmentation surgery. Bone graft volumes were compared after maxillary sinus floor augmentation surgery and a graft healing interval of several months. To analyze the relation between bone volume changes with the independent variables, patients' gender, age, alveolar crest height and width, and graft healing time interval, a multi-level extension of linear regression was applied. A residual bone height of 6.0 mm (SD = 3.6 mm) and 6.2 mm (SD = 3.6 mm) was found at the left and right sides, respectively. Moreover, alveolar bone widths of 6.5 mm (SD = 2.2 mm) and 7.0 mm (SD = 2.3 mm) at the premolars, and 8.8 mm (SD = 2.2 mm) and 8.9 mm (SD = 2.5 mm) at the molars regions were found at the left and right site, respectively. Bone graft volume decreased by 25.0% (SD = 21.0%) after 4.7 months (SD = 2.7, median = 4.0 months) of healing time. The variables "age" (P = 0.009) and mean alveolar crest "bone height" (P = 0.043), showed a significant influence on bone graft resorption. A decrease of 1.0% (SE = 0.3%) of bone graft resorption was found for each year the patient grew older, and an increase in bone graft resorption of 1.8% (SE = 0.8%) was found for each mm of original bone height before sinus floor augmentation. Graft resorption occurs when using autologous bone grafts for maxillary sinus augmentation. Alveolar crest bone height and patient age have a significant effect on graft resorption, with increased resorption for higher alveolar crest bone height and decreased resorption for older patients. Consequently, patient characteristics that affect the process of bone graft resorption should be given full consideration, when performing sinus augmentation surgery. © 2011 John Wiley & Sons A/S.

Density functional theory calculations of 95Mo NMR parameters in solid-state compounds.

PubMed

Cuny, Jérôme; Furet, Eric; Gautier, Régis; Le Pollès, Laurent; Pickard, Chris J; d'Espinose de Lacaillerie, Jean-Baptiste

2009-12-21

The application of periodic density functional theory-based methods to the calculation of (95)Mo electric field gradient (EFG) and chemical shift (CS) tensors in solid-state molybdenum compounds is presented. Calculations of EFG tensors are performed using the projector augmented-wave (PAW) method. Comparison of the results with those obtained using the augmented plane wave + local orbitals (APW+lo) method and with available experimental values shows the reliability of the approach for (95)Mo EFG tensor calculation. CS tensors are calculated using the recently developed gauge-including projector augmented-wave (GIPAW) method. This work is the first application of the GIPAW method to a 4d transition-metal nucleus. The effects of ultra-soft pseudo-potential parameters, exchange-correlation functionals and structural parameters are precisely examined. Comparison with experimental results allows the validation of this computational formalism.

Logic flowgraph methodology - A tool for modeling embedded systems

NASA Technical Reports Server (NTRS)

Muthukumar, C. T.; Guarro, S. B.; Apostolakis, G. E.

1991-01-01

The logic flowgraph methodology (LFM), a method for modeling hardware in terms of its process parameters, has been extended to form an analytical tool for the analysis of integrated (hardware/software) embedded systems. In the software part of a given embedded system model, timing and the control flow among different software components are modeled by augmenting LFM with modified Petrinet structures. The objective of the use of such an augmented LFM model is to uncover possible errors and the potential for unanticipated software/hardware interactions. This is done by backtracking through the augmented LFM mode according to established procedures which allow the semiautomated construction of fault trees for any chosen state of the embedded system (top event). These fault trees, in turn, produce the possible combinations of lower-level states (events) that may lead to the top event.

Contingency power for a small turboshaft engine by using water injection into turbine cooling air

NASA Technical Reports Server (NTRS)

Biesiadny, Thomas J.; Klann, Gary A.

1992-01-01

Because of one-engine-inoperative (OEI) requirements, together with hot-gas reingestion and hot-day, high-altitude take-off situations, power augmentation for multiengine rotorcraft has always been of critical interest. However, power augmentation by using overtemperature at the turbine inlet will shorten turbine life unless a method of limiting thermal and mechanical stress is found. A possible solution involves allowing the turbine inlet temperature to rise to augment power while injecting water into the turbine cooling air to limit hot-section metal temperatures. An experimental water injection device was installed in an engine and successfully tested. Although concern for unprotected subcomponents in the engine hot section prevented demonstration of the technique's maximum potential, it was still possible to demonstrate increases in power while maintaining nearly constant turbine rotor blade temperature.

B-52 stability augmentation system reliability

NASA Technical Reports Server (NTRS)

Bowling, T. C.; Key, L. W.

1976-01-01

The B-52 SAS (Stability Augmentation System) was developed and retrofitted to nearly 300 aircraft. It actively controls B-52 structural bending, provides improved yaw and pitch damping through sensors and electronic control channels, and puts complete reliance on hydraulic control power for rudder and elevators. The system has experienced over 300,000 flight hours and has exhibited service reliability comparable to the results of the reliability test program. Development experience points out numerous lessons with potential application in the mechanization and development of advanced technology control systems of high reliability.

Prevention of cement leakage into the hip joint by a standard cement plug during PFN-A cement augmentation: a technical note.

PubMed

Hanke, M; Djonov, V; Tannast, M; Keel, M J; Bastian, J D

2016-06-01

Medial penetration of the helical blade into the hip joint after fixation of trochanteric fractures using the proximal femur nail antirotation (PFN-A) is a potential failure mode. In low demand patients a blade exchange with cement augmentation may be an option if conversion to total hip arthroplasty is unfeasible to salvage the cut-through. This article describes a technique to avoid intraarticular cement leakage using a cement plug to close the defect in the femoral head caused by the cut-through.

Effects of phenytoin on N100 augmenting/reducing and the late positive complex of the event-related potential: a topographic analysis.

PubMed

Pritchard, W S; Barratt, E S; Faulk, D M; Brandt, M E; Bryant, S G

1986-01-01

The effects of 100 mg of phenytoin on the topographic distribution of augmenting/reducing (amplitude response/nonresponse to increases in stimulus intensity) of the visual N100 component of the event-related potential (ERP) were examined. In normal subjects, visual N100 augmenting is associated with impulsivity and attentional distraction. Effects of phenytoin on the topographic distributions of the P300 and slow-wave cognitive ERP components were also examined. Subjects counted the total number of light flashes presented at two highly discriminable but equiprobable intensities. Results indicated that phenytoin had a significant reducing effect on the intensity response of N100 at the vertex and anterior temporal electrode sites, and approached significance at the frontal pole. That is, at these loci N100 showed less of an increase in amplitude (or, in some subjects, more of a decrease) in going from baseline to drug than in going from baseline to placebo. Results also indicated that phenytoin significantly enhanced the amplitude of the frontal, negative portion of slow wave, but not the posterior, positive portion or the P300 component. These findings are consistent with behavioral evidence that phenytoin reduces impulsivity and improves concentration.

Modeling and computational simulation and the potential of virtual and augmented reality associated to the teaching of nanoscience and nanotechnology

NASA Astrophysics Data System (ADS)

Ribeiro, Allan; Santos, Helen

With the advent of new information and communication technologies (ICTs), the communicative interaction changes the way of being and acting of people, at the same time that changes the way of work activities related to education. In this range of possibilities provided by the advancement of computational resources include virtual reality (VR) and augmented reality (AR), are highlighted as new forms of information visualization in computer applications. While the RV allows user interaction with a virtual environment totally computer generated; in RA the virtual images are inserted in real environment, but both create new opportunities to support teaching and learning in formal and informal contexts. Such technologies are able to express representations of reality or of the imagination, as systems in nanoscale and low dimensionality, being imperative to explore, in the most diverse areas of knowledge, the potential offered by ICT and emerging technologies. In this sense, this work presents computer applications of virtual and augmented reality developed with the use of modeling and simulation in computational approaches to topics related to nanoscience and nanotechnology, and articulated with innovative pedagogical practices.

Leveraging algal omics to reveal potential targets for augmenting TAG accumulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arora, Neha; Pienkos, Philip T.; Pruthi, Vikas

Ongoing global efforts to commercialize microalgal biofuels have expedited the use of multi-omics techniques to gain insights into lipid biosynthetic pathways. Functional genomics analyses have recently been employed to complement existing sequence-level omics studies, shedding light on the dynamics of lipid synthesis and its interplay with other cellular metabolic pathways, thus revealing possible targets for metabolic engineering. Here, we review the current status of algal omics studies to reveal potential targets to augment TAG accumulation in various microalgae. Here, this review specifically aims to examine and catalog systems level data related to stress-induced TAG accumulation in oleaginous microalgae and informmore » future metabolic engineering strategies to develop strains with enhanced bioproductivity, which could pave a path for sustainable green energy.« less

Leveraging Algal Omics to Reveal Potential Targets for Augmenting TAG Accumulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guarnieri, Michael T; Pienkos, Philip T; Arora, Neha

2018-04-18

Ongoing global efforts to commercialize microalgal biofuels have expedited the use of multi-omics techniques to gain insights into lipid biosynthetic pathways. Functional genomics analyses have recently been employed to complement existing sequence-level omics studies, shedding light on the dynamics of lipid synthesis and its interplay with other cellular metabolic pathways, thus revealing possible targets for metabolic engineering. Here, we review the current status of algal omics studies to reveal potential targets to augment TAG accumulation in various microalgae. This review specifically aims to examine and catalog systems level data related to stress-induced TAG accumulation in oleaginous microalgae and inform futuremore » metabolic engineering strategies to develop strains with enhanced bioproductivity, which could pave a path for sustainable green energy.« less

A Heads-Up Display for Diabetic Limb Salvage Surgery

PubMed Central

Rankin, Timothy M.; Giovinco, Nicholas A.; Mills, Joseph L.; Matsuoka, Yoky

2014-01-01

Although the use of augmented reality has been well described over the past several years, available devices suffer from high cost, an uncomfortable form factor, suboptimal battery life, and lack an app-based developer ecosystem. This article describes the potential use of a novel, consumer-based, wearable device to assist surgeons in real time during limb preservation surgery and clinical consultation. Using routine intraoperative, clinical, and educational case examples, we describe the use of a wearable augmented reality device (Google Glass; Google, Mountain View, CA). The device facilitated hands-free, rapid communication, documentation, and consultation. An eyeglass-mounted screen form factor has the potential to improve communication, safety, and efficiency of intraoperative and clinical care. We believe this represents a natural progression toward union of medical devices with consumer technology. PMID:24876445

Leveraging algal omics to reveal potential targets for augmenting TAG accumulation

DOE PAGES

Arora, Neha; Pienkos, Philip T.; Pruthi, Vikas; ...

2018-04-18

Ongoing global efforts to commercialize microalgal biofuels have expedited the use of multi-omics techniques to gain insights into lipid biosynthetic pathways. Functional genomics analyses have recently been employed to complement existing sequence-level omics studies, shedding light on the dynamics of lipid synthesis and its interplay with other cellular metabolic pathways, thus revealing possible targets for metabolic engineering. Here, we review the current status of algal omics studies to reveal potential targets to augment TAG accumulation in various microalgae. Here, this review specifically aims to examine and catalog systems level data related to stress-induced TAG accumulation in oleaginous microalgae and informmore » future metabolic engineering strategies to develop strains with enhanced bioproductivity, which could pave a path for sustainable green energy.« less

A see through future: augmented reality and health information systems.

PubMed

Monkman, Helen; Kushniruk, Andre W

2015-01-01

Augmented Reality (AR) is a method whereby virtual objects are superimposed on the real world. AR technology is becoming increasingly accessible and affordable and it has many potential health applications. This paper discusses current research on AR health applications such as medical education and medical practice. Some of the potential future uses for this technology (e.g., health information systems, consumer health applications) will also be presented. Additionally, there will be a discussion outlining some of usability and human factors challenges associated with AR in healthcare. It is expected that AR will become increasingly prevalent in healthcare; however, further investigation is required to demonstrate that they provide benefits over traditional methods. Moreover, AR applications must be thoroughly tested to ensure they do not introduce new errors into practice and have patient safety implications.

Leveraging algal omics to reveal potential targets for augmenting TAG accumulation.

PubMed

Arora, Neha; Pienkos, Philip T; Pruthi, Vikas; Poluri, Krishna Mohan; Guarnieri, Michael T

2018-04-18

Ongoing global efforts to commercialize microalgal biofuels have expedited the use of multi-omics techniques to gain insights into lipid biosynthetic pathways. Functional genomics analyses have recently been employed to complement existing sequence-level omics studies, shedding light on the dynamics of lipid synthesis and its interplay with other cellular metabolic pathways, thus revealing possible targets for metabolic engineering. Here, we review the current status of algal omics studies to reveal potential targets to augment TAG accumulation in various microalgae. This review specifically aims to examine and catalog systems level data related to stress-induced TAG accumulation in oleaginous microalgae and inform future metabolic engineering strategies to develop strains with enhanced bioproductivity, which could pave a path for sustainable green energy. Copyright © 2018. Published by Elsevier Inc.

An Experimental Evaluation of Generalized Predictive Control for Tiltrotor Aeroelastic Stability Augmentation in Airplane Mode of Flight

NASA Technical Reports Server (NTRS)

Kvaternik, Raymond G.; Piatak, David J.; Nixon, Mark W.; Langston, Chester W.; Singleton, Jeffrey D.; Bennett, Richard L.; Brown, Ross K.

2001-01-01

The results of a joint NASA/Army/Bell Helicopter Textron wind-tunnel test to assess the potential of Generalized Predictive Control (GPC) for actively controlling the swashplate of tiltrotor aircraft to enhance aeroelastic stability in the airplane mode of flight are presented. GPC is an adaptive time-domain predictive control method that uses a linear difference equation to describe the input-output relationship of the system and to design the controller. The test was conducted in the Langley Transonic Dynamics Tunnel using an unpowered 1/5-scale semispan aeroelastic model of the V-22 that was modified to incorporate a GPC-based multi-input multi-output control algorithm to individually control each of the three swashplate actuators. Wing responses were used for feedback. The GPC-based control system was highly effective in increasing the stability of the critical wing mode for all of the conditions tested, without measurable degradation of the damping in the other modes. The algorithm was also robust with respect to its performance in adjusting to rapid changes in both the rotor speed and the tunnel airspeed.

First principles study of the ground state properties of Si, Ga, and Ge doped Fe50Al50

NASA Astrophysics Data System (ADS)

Pérez, Carlos Ariel Samudio; dos Santos, Antonio Vanderlei

2018-06-01

The first principles calculation of the structural, electronic and associated properties of the Fe50Al50 alloy (B2 phase) doped by s-p elements (Im = Si, Ga, and Ge) are performed as a function of the atomic concentration on the basis of the Full Potential Linear Augmented Plane Wave (FP-LAPW) method as implemented in the WIEN2k code. The Al substitution by Im (Si and Ge) atoms (principally at a concentration of 6.25 at%) induces a pronounced redistribution of the electronic charge leading to a strong Fe-Im interaction with covalent bonding character. At the same time, decrease the lattice volume (V) while increase the bulk modulus (B). For the alloys containing Ga, the Fe-Ga interaction is also observed but the V and B of the alloy are very near to that of pure Fe-Al alloy. The magnetic moment and hyperfine parameters observed at the lattice sites of studied alloys also show variations, they increase or decrease in relation to that in Fe50Al50 according to the Im that substitutes Al.

GW study of topological insulators Bi2Se3, Bi2Te3, and Sb2Te3: Beyond the perturbative one-shot approach

NASA Astrophysics Data System (ADS)

Aguilera, Irene; Friedrich, Christoph; Bihlmayer, Gustav; Blügel, Stefan

2013-07-01

We present GW calculations of the topological insulators Bi2Se3, Bi2Te3, and Sb2Te3 within the all-electron full-potential linearized augmented-plane-wave formalism. Quasiparticle effects produce significant qualitative changes in the band structures of these materials when compared to density functional theory (DFT), especially at the Γ point, where band inversion takes place. There, the widely used perturbative one-shot GW approach can produce unphysical band dispersions, as the quasiparticle wave functions are forced to be identical to the noninteracting single-particle states. We show that a treatment beyond the perturbative approach, which incorporates the off-diagonal GW matrix elements and thus enables many-body hybridization to be effective in the quasiparticle wave functions, is crucial in these cases to describe the characteristics of the band inversion around the Γ point in an appropriate way. In addition, this beyond one-shot GW approach allows us to calculate the values of the Z2 topological invariants and compare them with those previously obtained within DFT.

First-principle calculations of structural, electronic, optical, elastic and thermal properties of MgXAs2 (X=Si, Ge) compounds

NASA Astrophysics Data System (ADS)

Cheddadi, S.; Boubendira, K.; Meradji, H.; Ghemid, S.; Hassan, F. El Haj; Lakel, S.; Khenata, R.

2017-12-01

First-principle calculations on the structural, electronic, optical, elastic and thermal properties of the chalcopyrite MgXAs2 (X=Si, Ge) have been performed within the density functional theory (DFT) using the full-potential linearized augmented plane wave (FP-LAPW) method. The obtained equilibrium structural parameters are in good agreement with the available experimental data and theoretical results. The calculated band structures reveal a direct energy band gap for the interested compounds. The predicted band gaps using the modified Becke-Johnson (mBJ) exchange approximation are in fairly good agreement with the experimental data. The optical constants such as the dielectric function, refractive index, and the extinction coefficient are calculated and analysed. The independent elastic parameters namely, C_{11}, C_{12}, C_{13}, C_{33}, C_{44} and C_{66 } are evaluated. The effects of temperature and pressure on some macroscopic properties of MgSiAs2 and MgGeAs2 are predicted using the quasiharmonic Debye model in which the lattice vibrations are taken into account.

Electronic, magnetic properties and phase diagrams of system with Fe4N compound: An ab initio calculations and Monte Carlo study

NASA Astrophysics Data System (ADS)

Masrour, R.; Jabar, A.; Hlil, E. K.

2018-05-01

Self-consistent ab initio calculations, based on Density Functional Theory (DFT) approach and using Full potential Linear Augmented Plane Wave (FLAPW) method, are performed to investigate the electronic and magnetic properties of the Fe4N compound. Polarized spin and spin-orbit coupling are included in calculations within the framework of the ferromagnetic state between Fe(I) and Fe(II) in Fe4N compound. We have used the obtained data from abinitio calculations as an input in Monte Carlo simulation to calculate the magnetic properties of this compounds such as the ground state phase diagrams, total and partial magnetization of Fe(I) and Fe(II) as well as the transition temperatures are computed. The variation of magnetization with the crystal field are also studied. The magnetic hysteresis cycle of the same Fe4N compound are determined for different values of temperatures and crystal field values. The two-step hysteresis loop are evidenced, which is typical for Fe4N structure. The ferromagnetic and superparamagnetic phase is observed as well.

Evolution of the orbitals Dy-4f in the DyB2 compound using the LDA, PBE approximations, and the PBE0 hybrid functional

NASA Astrophysics Data System (ADS)

Rasero Causil, Diego; Ortega López, César; Espitia Rico, Miguel

2018-04-01

Computational calculations of total energy based on density functional theory were used to investigate the structural, electronic, and magnetic properties of the DyB2 compounds in the hexagonal structure. The calculations were carried out by means of the full-potential linearized augmented plane wave (FP-LAPW) method, employing the computational Wien2k package. The local density approximation (LDA) and the generalized gradient approximation (GGA) were used for the electron-electron interactions. Additionally, we used the functional hybrid PBE0 for a better description the electronic and magnetic properties, because the DyB2 compound is a strongly-correlated system. We found that the calculated lattice constant agrees well with the values reported theoretically and experimentally. The density of states (DOS) calculation shows that the compound exhibits a metallic behavior and has magnetic properties, with a total magnetic moment of 5.47 μ0/cell determined mainly by the 4f states of the rare earth elements. The functional PBE0 shows a strong localization of the Dy-4f orbitals.

Optoelectronic and transport properties of LiBZ (B = Al, In, Ga and Z = Si, Ge, Sn) semiconductors

NASA Astrophysics Data System (ADS)

Shah, Syed Hatim; Khan, Shah Haider; Laref, A.; Murtaza, G.

2018-02-01

Half-Heusler compounds LiBZ (B = Al, In, Ga and Z = Si, Ge, Sn) are comprehensively investigated using state of the art full potential linearized augmented plane wave (FP-LAPW) method. Stable geometry of the compounds obtained through energy minimization procedure. Lattice constant increased while bulk modulus decreased in replacing the ions of size increasing from top to bottom of the periodic table. Band structure calculations show LiInGe and LiInSn as direct bandgap while LiAlSi, LiInGe and LiGaSn indirect bandgap semiconductors. Density of states demonstrates mixed s, p, d states of cations and anions in the valence and conduction bands. These compounds have mixed ionic and covalent bonding. Compounds show dominant optical response in the visible and low frequency ultraviolet energy region. The transport properties of the compounds are described in terms of Seebeck coefficient, electrical and thermal conductivities. The calculated figure of merit of LiAlSi is in good agreement with the recent experimental results.

Adsorbing H₂S onto a single graphene sheet: A possible gas sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reshak, A. H., E-mail: maalidph@yahoo.co.uk; Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis; Auluck, S.

2014-09-14

The electronic structure of pristine graphene sheet and the resulting structure of adsorbing a single molecule of H₂S on pristine graphene in three different sites (bridge, top, and hollow) are studied using the full potential linearized augmented plane wave method. Our calculations show that the adsorption of H₂S molecule on the bridge site opens up a small direct energy gap of about 0.1 eV at symmetry point M, while adsorption of H₂S on top site opens a gap of 0.3 eV around the symmetry point K. We find that adsorbed H₂S onto the hollow site of pristine graphene sheet causesmore » to push the conduction band minimum and the valence band maximum towards Fermi level resulting in a metallic behavior. Comparing the angular momentum decomposition of the atoms projected electronic density of states of pristine graphene sheet with that of H₂S–graphene for three different cases, we find a significant influence of the location of the H₂S molecule on the electronic properties especially the strong hybridization between H₂S molecule and graphene sheet.« less

Band-gap tuning and optical response of two-dimensional SixC1 -x : A first-principles real-space study of disordered two-dimensional materials

NASA Astrophysics Data System (ADS)

Sadhukhan, Banasree; Singh, Prashant; Nayak, Arabinda; Datta, Sujoy; Johnson, Duane D.; Mookerjee, Abhijit

2017-08-01

We present a real-space formulation for calculating the electronic structure and optical conductivity of random alloys based on Kubo-Greenwood formalism interfaced with augmented space recursion technique [Mookerjee, J. Phys. C 6, 1340 (1973), 10.1088/0022-3719/6/8/003] formulated with the tight-binding linear muffin-tin orbital basis with the van Leeuwen-Baerends corrected exchange potential [Singh, Harbola, Hemanadhan, Mookerjee, and Johnson, Phys. Rev. B 93, 085204 (2016), 10.1103/PhysRevB.93.085204]. This approach has been used to quantitatively analyze the effect of chemical disorder on the configuration averaged electronic properties and optical response of two-dimensional honeycomb siliphene SixC1 -x beyond the usual Dirac-cone approximation. We predicted the quantitative effect of disorder on both the electronic structure and optical response over a wide energy range, and the results are discussed in the light of the available experimental and other theoretical data. Our proposed formalism may open up a facile way for planned band-gap engineering in optoelectronic applications.

Artificial Intelligence, DNA Mimicry, and Human Health.

PubMed

Stefano, George B; Kream, Richard M

2017-08-14

The molecular evolution of genomic DNA across diverse plant and animal phyla involved dynamic registrations of sequence modifications to maintain existential homeostasis to increasingly complex patterns of environmental stressors. As an essential corollary, driver effects of positive evolutionary pressure are hypothesized to effect concerted modifications of genomic DNA sequences to meet expanded platforms of regulatory controls for successful implementation of advanced physiological requirements. It is also clearly apparent that preservation of updated registries of advantageous modifications of genomic DNA sequences requires coordinate expansion of convergent cellular proofreading/error correction mechanisms that are encoded by reciprocally modified genomic DNA. Computational expansion of operationally defined DNA memory extends to coordinate modification of coding and previously under-emphasized noncoding regions that now appear to represent essential reservoirs of untapped genetic information amenable to evolutionary driven recruitment into the realm of biologically active domains. Additionally, expansion of DNA memory potential via chemical modification and activation of noncoding sequences is targeted to vertical augmentation and integration of an expanded cadre of transcriptional and epigenetic regulatory factors affecting linear coding of protein amino acid sequences within open reading frames.

First-Principles Study on the Structural and Magnetic Properties of Iron Hydride

NASA Astrophysics Data System (ADS)

Tsumuraya, Takao; Matsuura, Yasuyuki; Shishidou, Tatsuya; Oguchi, Tamio

2012-06-01

The magnetic and structural properties of iron hydride FeH with the double hexagonal close-packed (dhcp) and hexagonal close-packed (hcp) structures are investigated by first-principles density-functional theory calculations with a spin-polarized form of generalized gradient approximation. All the calculations are performed using all-electron full-potential linearized augmented plane wave method. Both dhcp and hcp FeH are ferromagnetic at ambient pressure. The ferromagnetic ordering of the dhcp structure collapses at a pressure of 48 GPa, while that of the hcp structure vanishes gradually from 48 GPa. The modification in the density of states (DOS) due to the applied pressure causes the collapse of the magnetization. The difference in magnetic moment reduction between dhcp and hcp FeH is attributed to their DOS around the Fermi level. The calculated magnetocrystalline anisotropy energies between in-plane and out-of-plane spin orientations are found to be 124 μeV/Fe for the dhcp structure, and 100 μeV/Fe for the hcp structure. The easy axis is in-plane direction for both structures.

Bone Repair and Military Readiness

DTIC Science & Technology

2012-10-25

formation. Orthopedic surgeons have had to adapt surgical techniques to account for issues with cementing total joint prostheses and subsequent total joint ...the silorane composite has the potential to support osseous integration around the cemented total joint implant and may generate less immunogenic wear...factors, and potential for osseointegration/osseoinduction, this material has potential to be used for screw augmentation, total hip/knee joint

Fluid Flow and Heat Transfer Analysis of a Nanofluid Containing Motile Gyrotactic Micro-Organisms Passing a Nonlinear Stretching Vertical Sheet in the Presence of a Non-Uniform Magnetic Field; Numerical Approach

PubMed Central

M. Mehryan, S. A.; Moradi Kashkooli, Farshad; Soltani, M.; Raahemifar, Kaamran

2016-01-01

The behavior of a water-based nanofluid containing motile gyrotactic micro-organisms passing an isothermal nonlinear stretching sheet in the presence of a non-uniform magnetic field is studied numerically. The governing partial differential equations including continuity, momentums, energy, concentration of the nanoparticles, and density of motile micro-organisms are converted into a system of the ordinary differential equations via a set of similarity transformations. New set of equations are discretized using the finite difference method and have been linearized by employing the Newton’s linearization technique. The tri-diagonal system of algebraic equations from discretization is solved using the well-known Thomas algorithm. The numerical results for profiles of velocity, temperature, nanoparticles concentration and density of motile micro-organisms as well as the local skin friction coefficient Cfx, the local Nusselt number Nux, the local Sherwood number Shx and the local density number of the motile microorganism Nnx are expressed graphically and described in detail. This investigation shows the density number of the motile micro-organisms enhances with rise of M, Gr/Re2, Pe and Ω but it decreases with augment of Rb and n. Also, Sherwood number augments with an increase of M and Gr/Re2, while decreases with n, Rb, Nb and Nr. To show the validity of the current results, a comparison between the present results and the existing literature has been carried out. PMID:27322536

Randomised controlled clinical trial of augmentation of the alveolar ridge using recombinant human bone morphogenetic protein 2 with hydroxyapatite and bovine-derived xenografts: comparison of changes in volume.

PubMed

Nam, J W; Khureltogtokh, S; Choi, H M; Lee, A R; Park, Y B; Kim, H J

2017-10-01

The aim of this randomised controlled clinical trial was to assess the early efficacy of bone morphogenetic protein-2 with hydroxyapatite granules (BMP-2/hydroxyapatite) on augmentation of the alveolar ridge, by comparing changes in volume with those associated with the use of an inorganic bovine-derived xenograft (BDX). We studied 20 patients who were divided into two groups using a table of random numbers, and BMP-2/hydroxyapatite and BDX were applied accordingly. Computed tomographic (CT) images and panoramic radiographs were obtained immediately after operation and four months later. CT images were reconstructed in three dimensions to measure volumetric changes, and linear measurements were made on panoramic images. The mean (SD) absorption rates for BMP-2/hydroxyapatite and BDX were 13.2 (8.8)% and 13.8 (20.5)%, respectively. While the mean value did not differ significantly between the two materials, the SD was higher in the BDX group than in the BMP-2/hydroxyapatite group. No clinically important complications occurred in either group. We conclude that both BMP-2/hydroxyapatite and BDX were effective in augmenting the alveolar ridge, but BMP-2/hydroxyapatite seemed to be more useful in complicated bone defects. Copyright © 2017 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

ACCURATE SOLUTION AND GRADIENT COMPUTATION FOR ELLIPTIC INTERFACE PROBLEMS WITH VARIABLE COEFFICIENTS

PubMed Central

LI, ZHILIN; JI, HAIFENG; CHEN, XIAOHONG

2016-01-01

A new augmented method is proposed for elliptic interface problems with a piecewise variable coefficient that has a finite jump across a smooth interface. The main motivation is not only to get a second order accurate solution but also a second order accurate gradient from each side of the interface. The key of the new method is to introduce the jump in the normal derivative of the solution as an augmented variable and re-write the interface problem as a new PDE that consists of a leading Laplacian operator plus lower order derivative terms near the interface. In this way, the leading second order derivatives jump relations are independent of the jump in the coefficient that appears only in the lower order terms after the scaling. An upwind type discretization is used for the finite difference discretization at the irregular grid points near or on the interface so that the resulting coefficient matrix is an M-matrix. A multi-grid solver is used to solve the linear system of equations and the GMRES iterative method is used to solve the augmented variable. Second order convergence for the solution and the gradient from each side of the interface has also been proved in this paper. Numerical examples for general elliptic interface problems have confirmed the theoretical analysis and efficiency of the new method. PMID:28983130

Experimental Design for Hanford Low-Activity Waste Glasses with High Waste Loading

DOE Office of Scientific and Technical Information (OSTI.GOV)

Piepel, Gregory F.; Cooley, Scott K.; Vienna, John D.

This report discusses the development of an experimental design for the initial phase of the Hanford low-activity waste (LAW) enhanced glass study. This report is based on a manuscript written for an applied statistics journal. Appendices A, B, and E include additional information relevant to the LAW enhanced glass experimental design that is not included in the journal manuscript. The glass composition experimental region is defined by single-component constraints (SCCs), linear multiple-component constraints (MCCs), and a nonlinear MCC involving 15 LAW glass components. Traditional methods and software for designing constrained mixture experiments with SCCs and linear MCCs are not directlymore » applicable because of the nonlinear MCC. A modification of existing methodology to account for the nonlinear MCC was developed and is described in this report. One of the glass components, SO 3, has a solubility limit in glass that depends on the composition of the balance of the glass. A goal was to design the experiment so that SO 3 would not exceed its predicted solubility limit for any of the experimental glasses. The SO 3 solubility limit had previously been modeled by a partial quadratic mixture model expressed in the relative proportions of the 14 other components. The partial quadratic mixture model was used to construct a nonlinear MCC in terms of all 15 components. In addition, there were SCCs and linear MCCs. This report describes how a layered design was generated to (i) account for the SCCs, linear MCCs, and nonlinear MCC and (ii) meet the goals of the study. A layered design consists of points on an outer layer, and inner layer, and a center point. There were 18 outer-layer glasses chosen using optimal experimental design software to augment 147 existing glass compositions that were within the LAW glass composition experimental region. Then 13 inner-layer glasses were chosen with the software to augment the existing and outer-layer glasses. The experimental design was completed by a center-point glass, a Vitreous State Laboratory glass, and replicates of the center point and Vitreous State Laboratory glasses.« less

Projection Operator: A Step Towards Certification of Adaptive Controllers

NASA Technical Reports Server (NTRS)

Larchev, Gregory V.; Campbell, Stefan F.; Kaneshige, John T.

2010-01-01

One of the major barriers to wider use of adaptive controllers in commercial aviation is the lack of appropriate certification procedures. In order to be certified by the Federal Aviation Administration (FAA), an aircraft controller is expected to meet a set of guidelines on functionality and reliability while not negatively impacting other systems or safety of aircraft operations. Due to their inherent time-variant and non-linear behavior, adaptive controllers cannot be certified via the metrics used for linear conventional controllers, such as gain and phase margin. Projection Operator is a robustness augmentation technique that bounds the output of a non-linear adaptive controller while conforming to the Lyapunov stability rules. It can also be used to limit the control authority of the adaptive component so that the said control authority can be arbitrarily close to that of a linear controller. In this paper we will present the results of applying the Projection Operator to a Model-Reference Adaptive Controller (MRAC), varying the amount of control authority, and comparing controller s performance and stability characteristics with those of a linear controller. We will also show how adjusting Projection Operator parameters can make it easier for the controller to satisfy the certification guidelines by enabling a tradeoff between controller s performance and robustness.

Scaled effective on-site Coulomb interaction in the DFT+U method for correlated materials

NASA Astrophysics Data System (ADS)

Nawa, Kenji; Akiyama, Toru; Ito, Tomonori; Nakamura, Kohji; Oguchi, Tamio; Weinert, M.

2018-01-01

The first-principles calculation of correlated materials within density functional theory remains challenging, but the inclusion of a Hubbard-type effective on-site Coulomb term (Ueff) often provides a computationally tractable and physically reasonable approach. However, the reported values of Ueff vary widely, even for the same ionic state and the same material. Since the final physical results can depend critically on the choice of parameter and the computational details, there is a need to have a consistent procedure to choose an appropriate one. We revisit this issue from constraint density functional theory, using the full-potential linearized augmented plane wave method. The calculated Ueff parameters for the prototypical transition-metal monoxides—MnO, FeO, CoO, and NiO—are found to depend significantly on the muffin-tin radius RMT, with variations of more than 2-3 eV as RMT changes from 2.0 to 2.7 aB. Despite this large variation in Ueff, the calculated valence bands differ only slightly. Moreover, we find an approximately linear relationship between Ueff(RMT) and the number of occupied localized electrons within the sphere, and give a simple scaling argument for Ueff; these results provide a rationalization for the large variation in reported values. Although our results imply that Ueff values are not directly transferable among different calculation methods (or even the same one with different input parameters such as RMT), use of this scaling relationship should help simplify the choice of Ueff.

GBAS Ionospheric Anomaly Monitoring Based on a Two-Step Approach

PubMed Central

Zhao, Lin; Yang, Fuxin; Li, Liang; Ding, Jicheng; Zhao, Yuxin

2016-01-01

As one significant component of space environmental weather, the ionosphere has to be monitored using Global Positioning System (GPS) receivers for the Ground-Based Augmentation System (GBAS). This is because an ionospheric anomaly can pose a potential threat for GBAS to support safety-critical services. The traditional code-carrier divergence (CCD) methods, which have been widely used to detect the variants of the ionospheric gradient for GBAS, adopt a linear time-invariant low-pass filter to suppress the effect of high frequency noise on the detection of the ionospheric anomaly. However, there is a counterbalance between response time and estimation accuracy due to the fixed time constants. In order to release the limitation, a two-step approach (TSA) is proposed by integrating the cascaded linear time-invariant low-pass filters with the adaptive Kalman filter to detect the ionospheric gradient anomaly. The performance of the proposed method is tested by using simulated and real-world data, respectively. The simulation results show that the TSA can detect ionospheric gradient anomalies quickly, even when the noise is severer. Compared to the traditional CCD methods, the experiments from real-world GPS data indicate that the average estimation accuracy of the ionospheric gradient improves by more than 31.3%, and the average response time to the ionospheric gradient at a rate of 0.018 m/s improves by more than 59.3%, which demonstrates the ability of TSA to detect a small ionospheric gradient more rapidly. PMID:27240367

Higher-dimensional Wannier functions of multiparameter Hamiltonians

NASA Astrophysics Data System (ADS)

Hanke, Jan-Philipp; Freimuth, Frank; Blügel, Stefan; Mokrousov, Yuriy

2015-05-01

When using Wannier functions to study the electronic structure of multiparameter Hamiltonians H(k ,λ ) carrying a dependence on crystal momentum k and an additional periodic parameter λ , one usually constructs several sets of Wannier functions for a set of values of λ . We present the concept of higher-dimensional Wannier functions (HDWFs), which provide a minimal and accurate description of the electronic structure of multiparameter Hamiltonians based on a single set of HDWFs. The obstacle of nonorthogonality of Bloch functions at different λ is overcome by introducing an auxiliary real space, which is reciprocal to the parameter λ . We derive a generalized interpolation scheme and emphasize the essential conceptual and computational simplifications in using the formalism, for instance, in the evaluation of linear response coefficients. We further implement the necessary machinery to construct HDWFs from ab initio within the full potential linearized augmented plane-wave method (FLAPW). We apply our implementation to accurately interpolate the Hamiltonian of a one-dimensional magnetic chain of Mn atoms in two important cases of λ : (i) the spin-spiral vector q and (ii) the direction of the ferromagnetic magnetization m ̂. Using the generalized interpolation of the energy, we extract the corresponding values of magnetocrystalline anisotropy energy, Heisenberg exchange constants, and spin stiffness, which compare very well with the values obtained from direct first principles calculations. For toy models we demonstrate that the method of HDWFs can also be used in applications such as the virtual crystal approximation, ferroelectric polarization, and spin torques.

Polar Lunar Regions: Exploiting Natural and Augmented Thermal Environments

NASA Technical Reports Server (NTRS)

Ryan, Robert E.; McKellip, Rodney; Brannon, David P.; Underwood, Lauren; Russell, Kristen J.

2007-01-01

In polar regions of the Moon, some areas within craters are permanently shadowed from solar illumination and can reach temperatures of 100 K or less. These regions could serve as cold traps, capturing ice and other volatile compounds. These potential ice stores have many applications for lunar exploration. Within double-shaded craters, even colder regions exist, with temperatures never exceeding 50 K in many cases. Observed temperatures suggest that these regions could enable equivalent liquid nitrogen cryogenic functions. These permanently shaded polar craters also offer unprecedented high-vacuum cryogenic environments, which in their current state could support cryogenic applications. Besides ice stores, the unique conditions at the lunar poles harbor an environment that provides an opportunity to reduce the power, weight, and total mass that needs to be carried from the Earth to the Moon for lunar exploration and research. Reducing the heat flux of geothermal, black body radiation can have significant impacts on the achievable temperature. With a few manmade augmentations, permanently shaded craters located near the lunar poles achieve temperatures even lower than those that naturally exist. Our analysis reveals that lightweight thermal shielding within shaded craters could create an environment several Kelvin above absolute zero. The temperature ranges of both naturally shaded and thermally augmented craters could enable the long-term storage of most gases, low-temperature superconductors for large magnetic fields, devices and advanced high-speed computing instruments. Augmenting thermal conditions in these craters could then be used as a basis for the development of an advanced thermal management architecture that would support a wide variety of cryogenically based applications. Lunar exploration and habitation capabilities would significantly benefit if permanently shaded craters, augmented with thermal shielding, were used to facilitate the operation of near absolute zero instruments, including a wide variety of cryogenically based propulsion, energy, communication, sensing, and computing devices. The required burden of carrying massive life-supporting components from the Earth to the Moon for lunar exploration and research potentially could be reduced.

Real-time 3D image reconstruction guidance in liver resection surgery

PubMed Central

Nicolau, Stephane; Pessaux, Patrick; Mutter, Didier; Marescaux, Jacques

2014-01-01

Background Minimally invasive surgery represents one of the main evolutions of surgical techniques. However, minimally invasive surgery adds difficulty that can be reduced through computer technology. Methods From a patient’s medical image [US, computed tomography (CT) or MRI], we have developed an Augmented Reality (AR) system that increases the surgeon’s intraoperative vision by providing a virtual transparency of the patient. AR is based on two major processes: 3D modeling and visualization of anatomical or pathological structures appearing in the medical image, and the registration of this visualization onto the real patient. We have thus developed a new online service, named Visible Patient, providing efficient 3D modeling of patients. We have then developed several 3D visualization and surgical planning software tools to combine direct volume rendering and surface rendering. Finally, we have developed two registration techniques, one interactive and one automatic providing intraoperative augmented reality view. Results From January 2009 to June 2013, 769 clinical cases have been modeled by the Visible Patient service. Moreover, three clinical validations have been realized demonstrating the accuracy of 3D models and their great benefit, potentially increasing surgical eligibility in liver surgery (20% of cases). From these 3D models, more than 50 interactive AR-assisted surgical procedures have been realized illustrating the potential clinical benefit of such assistance to gain safety, but also current limits that automatic augmented reality will overcome. Conclusions Virtual patient modeling should be mandatory for certain interventions that have now to be defined, such as liver surgery. Augmented reality is clearly the next step of the new surgical instrumentation but remains currently limited due to the complexity of organ deformations during surgery. Intraoperative medical imaging used in new generation of automated augmented reality should solve this issue thanks to the development of Hybrid OR. PMID:24812598

Manganese Porphyrin, MnTE-2-PyP5+, Acts as a Pro-Oxidant to Potentiate Glucocorticoid-Induced Apoptosis in Lymphoma Cells

PubMed Central

Jaramillo, Melba C.; Briehl, Margaret M.; Crapo, James D.; Haberle, Ines Batinic; Tome, Margaret E.

2012-01-01

Using current chemotherapy protocols, over 55% of lymphoma patients fail treatment. Novel agents are needed to improve lymphoma survival. The manganese porphyrin, MnTE-2-PyP5+, augments glucocorticoid-induced apoptosis in WEHI7.2 murine thymic lymphoma cells, suggesting that it may have potential as a lymphoma therapeutic. However, the mechanism by which MnTE-2-PyP5+ potentiates glucocorticoid-induced apoptosis is unknown. Previously, we showed that glucocorticoid treatment increases the steady state levels of hydrogen peroxide ([H2O2]ss) and oxidizes the redox environment in WEHI7.2 cells. In the current study, we found that when MnTE-2-PyP5+ is combined with glucocorticoids, it augments dexamethasone-induced oxidative stress however, it does not augment the [H2O2]ss levels. The combined treatment depletes GSH, oxidizes the 2GSH:GSSG ratio, and causes protein glutathionylation to a greater extent than glucocorticoid treatment alone. Removal of the glucocorticoid-generated H2O2 or depletion of glutathione by BSO prevents MnTE-2-PyP5+ from augmenting glucocorticoid-induced apoptosis. In combination with glucocorticoids, MnTE-2-PyP5+ glutathionylates p65 NF-κB and inhibits NF-κB activity. Inhibition of NF-κB with SN50, an NF-κB inhibitor, enhances glucocorticoid-induced apoptosis to the same extent as MnTE-2-PyP5+. Taken together, these findings indicate that: 1) H2O2 is important for MnTE-2-PyP5+ activity; 2) Mn-TE-2-PyP5+ cycles with GSH; and 3) MnTE-2-PyP5+ potentiates glucocorticoid-induced apoptosis by glutathionylating and inhibiting critical survival proteins, including NF-κB. In the clinic, over-expression of NF-κB is associated with a poor prognosis in lymphoma. MnTE-2-PyP5+ may therefore, synergize with glucocorticoids to inhibit NF-κB and improve current treatment. PMID:22330065

A new ab initio potential energy surface for the collisional excitation of HCN by para- and ortho-H{sub 2}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denis-Alpizar, Otoniel, E-mail: otonieldenisalpizar@gmail.com; Departamento de Física, Universidad de Matanzas, Matanzas 40100; Kalugina, Yulia

We present a new four-dimensional potential energy surface for the collisional excitation of HCN by H{sub 2}. Ab initio calculations of the HCN–H{sub 2} van der Waals complex, considering both molecules as rigid rotors, were carried out at the explicitly correlated coupled cluster with single, double, and perturbative triple excitations [CCSD(T)-F12a] level of theory using an augmented correlation-consistent triple zeta (aVTZ) basis set. The equilibrium structure is linear HCN–H{sub 2} with the nitrogen pointing towards H{sub 2} at an intermolecular separation of 7.20 a{sub 0}. The corresponding well depth is −195.20 cm{sup −1}. A secondary minimum of −183.59 cm{sup −1}more » was found for a T-shape configuration with the H of HCN pointing to the center of mass of H{sub 2}. We also determine the rovibrational energy levels of the HCN–para-H{sub 2} and HCN–ortho-H{sub 2} complexes. The calculated dissociation energies for the para and ortho complexes are 37.79 cm{sup −1} and 60.26 cm{sup −1}, respectively. The calculated ro-vibrational transitions in the HCN–H{sub 2} complex are found to agree by more than 0.5% with the available experimental data, confirming the accuracy of the potential energy surface.« less

Moving from Virtual Reality Exposure-Based Therapy to Augmented Reality Exposure-Based Therapy: A Review

PubMed Central

Baus, Oliver; Bouchard, Stéphane

2014-01-01

This paper reviews the move from virtual reality exposure-based therapy to augmented reality exposure-based therapy (ARET). Unlike virtual reality (VR), which entails a complete virtual environment (VE), augmented reality (AR) limits itself to producing certain virtual elements to then merge them into the view of the physical world. Although, the general public may only have become aware of AR in the last few years, AR type applications have been around since beginning of the twentieth century. Since, then, technological developments have enabled an ever increasing level of seamless integration of virtual and physical elements into one view. Like VR, AR allows the exposure to stimuli which, due to various reasons, may not be suitable for real-life scenarios. As such, AR has proven itself to be a medium through which individuals suffering from specific phobia can be exposed “safely” to the object(s) of their fear, without the costs associated with programing complete VEs. Thus, ARET can offer an efficacious alternative to some less advantageous exposure-based therapies. Above and beyond presenting what has been accomplished in ARET, this paper covers some less well-known aspects of the history of AR, raises some ARET related issues, and proposes potential avenues to be followed. These include the type of measures to be used to qualify the user’s experience in an augmented reality environment, the exclusion of certain AR-type functionalities from the definition of AR, as well as the potential use of ARET to treat non-small animal phobias, such as social phobia. PMID:24624073

Age protects from harmful effects produced by chronic intermittent hypoxia.

PubMed

Quintero, M; Olea, E; Conde, S V; Obeso, A; Gallego-Martin, T; Gonzalez, C; Monserrat, J M; Gómez-Niño, A; Yubero, S; Agapito, T

2016-03-15

Obstructive sleep apnoea (OSA) affects an estimated 3–7% of the adult population, the frequency doubling at ages >60–65 years. As it evolves, OSA becomes frequently associated with cardiovascular, metabolic and neuropsychiatric pathologies defining OSA syndrome (OSAS). Exposing experimental animals to chronic intermittent hypoxia (CIH) can be used as a model of the recurrent hypoxic and O2 desaturation patterns observed in OSA patients. CIH is an important OSA event triggering associated pathologies; CIH induces carotid body (CB)-driven exaggerated sympathetic tone and overproduction of reactive oxygen species, related to the pathogenic mechanisms of associated pathologies observed in OSAS. Aiming to discover why OSAS is clinically less conspicuous in aged patients, the present study compares CIH effects in young (3–4 months) and aged (22–24 months) rats. To define potential distinctive patterns of these pathogenic mechanisms, mean arterial blood pressure as the final CIH outcome was measured. In young rats, CIH augmented CB sensory responses to hypoxia, decreased hypoxic ventilation and augmented sympathetic activity (plasma catecholamine levels and renal artery content and synthesis rate). An increased brainstem integration of CB sensory input as a trigger of sympathetic activity is suggested. CIH also caused an oxidative status decreasing aconitase/fumarase ratio and superoxide dismutase activity. In aged animals, CIH minimally affected CB responses, ventilation and sympathetic-related parameters leaving redox status unaltered. In young animals, CIH caused hypertension and in aged animals, whose baseline blood pressure was augmented, CIH did not augment it further. Plausible mechanisms of the differences and potential significance of these findings for the diagnosis and therapy of OSAS are discussed.

Moving from virtual reality exposure-based therapy to augmented reality exposure-based therapy: a review.

PubMed

Baus, Oliver; Bouchard, Stéphane

2014-01-01

This paper reviews the move from virtual reality exposure-based therapy to augmented reality exposure-based therapy (ARET). Unlike virtual reality (VR), which entails a complete virtual environment (VE), augmented reality (AR) limits itself to producing certain virtual elements to then merge them into the view of the physical world. Although, the general public may only have become aware of AR in the last few years, AR type applications have been around since beginning of the twentieth century. Since, then, technological developments have enabled an ever increasing level of seamless integration of virtual and physical elements into one view. Like VR, AR allows the exposure to stimuli which, due to various reasons, may not be suitable for real-life scenarios. As such, AR has proven itself to be a medium through which individuals suffering from specific phobia can be exposed "safely" to the object(s) of their fear, without the costs associated with programing complete VEs. Thus, ARET can offer an efficacious alternative to some less advantageous exposure-based therapies. Above and beyond presenting what has been accomplished in ARET, this paper covers some less well-known aspects of the history of AR, raises some ARET related issues, and proposes potential avenues to be followed. These include the type of measures to be used to qualify the user's experience in an augmented reality environment, the exclusion of certain AR-type functionalities from the definition of AR, as well as the potential use of ARET to treat non-small animal phobias, such as social phobia.

Method of Conjugate Radii for Solving Linear and Nonlinear Systems

NASA Technical Reports Server (NTRS)

Nachtsheim, Philip R.

1999-01-01

This paper describes a method to solve a system of N linear equations in N steps. A quadratic form is developed involving the sum of the squares of the residuals of the equations. Equating the quadratic form to a constant yields a surface which is an ellipsoid. For different constants, a family of similar ellipsoids can be generated. Starting at an arbitrary point an orthogonal basis is constructed and the center of the family of similar ellipsoids is found in this basis by a sequence of projections. The coordinates of the center in this basis are the solution of linear system of equations. A quadratic form in N variables requires N projections. That is, the current method is an exact method. It is shown that the sequence of projections is equivalent to a special case of the Gram-Schmidt orthogonalization process. The current method enjoys an advantage not shared by the classic Method of Conjugate Gradients. The current method can be extended to nonlinear systems without modification. For nonlinear equations the Method of Conjugate Gradients has to be augmented with a line-search procedure. Results for linear and nonlinear problems are presented.

Observations From the Coupled Boundary Layer Air-Sea Transfer Experiment in Hurricanes

NASA Astrophysics Data System (ADS)

Black, P. G.

2006-12-01

The CBLAST field program conducted from 2002-2004 has shown that the wind speed range for which turbulent momentum and moisture exchange coefficients have been derived based upon direct flux measurements has been extended by 30 and 60 percent, respectively, from airborne observations in Hurricanes Fabian and Isabel in 2003. The drag coefficient (CD) values derived from CBLAST momentum flux measurements show CD becoming invariant with wind speed near a 23 ms-1 threshold rather than a hurricane-force threshold near 33 ms-1. Values above 23 ms-1 are lower than previous open ocean measurements. The Dalton number estimates (CE) derived from CBLAST moisture flux measurements are shown to be invariant with wind speed to 30 ms-1, in approximate agreement with previous measurements at lower winds. These observations imply a CE/CD ratio of approximately 0.7, suggesting that additional energy sources are necessary for hurricanes to achieve their maximum potential intensity. Two such additional mechanisms for augmented moisture flux in the boundary layer might be 1) augmented wave breaking by short-crested, fetch limited waves suggested by whitecap aerial coverage measurements, and 2) sea spray at high winds suggested by laboratory spray source function measurements. Linear coherent features in the hurricane boundary layer are a third mechanism, observed during CBLAST 2002 aircraft measurements, to have wavelengths of 0.9 to 1.2 km. Linear features of the same wavelength range were observed in nearly-concurrent RADARSAT Synthetic Aperture Radar (SAR) imagery. Arrays of drifting buoys and subsurface floats were successfully deployed ahead of Hurricanes Fabian (2003) and Frances (2004): 16 (6) and 38 (14) drifters (floats). Two types of surface drifters and three types of floats provided observations of surface and subsurface oceanic currents, temperature, salinity, gas exchange, bubble concentrations and surface wave spectra to a depth of 200 m on a continuous basis before, during and after storm passage. Float observations indicated deepening of the mixed layer from 40 to 120 m in approximately 8 hr with a corresponding decrease in SST in the right-rear quadrant of 3.2 ºC in 11 hr, roughly one-half inertial period. Strong inertial currents with a peak amplitude of 1.5 ms-1 were observed. Vertical structure showed the critical Richardson number was reached sporadically during the mixed-layer deepening event, suggesting shear-induced mixing as a prominent mechanism during storm passage.

Percussive Augmenter of Rotary Drills (PARoD)

NASA Technical Reports Server (NTRS)

Badescu, Mircea; Bar-Cohen, Yoseph; Sherrit, Stewart; Bao, Xiaoqi; Chang, Zensheu; Donnelly, Chris; Aldrich, Jack

2012-01-01

Increasingly, NASA exploration mission objectives include sample acquisition tasks for in-situ analysis or for potential sample return to Earth. To address the requirements for samplers that could be operated at the conditions of the various bodies in the solar system, a piezoelectric actuated percussive sampling device was developed that requires low preload (as low as 10N) which is important for operation at low gravity. This device can be made as light as 400g, can be operated using low average power, and can drill rocks as hard as basalt. Significant improvement of the penetration rate was achieved by augmenting the hammering action by rotation and use of a fluted bit to provide effective cuttings removal. Generally, hammering is effective in fracturing drilled media while rotation of fluted bits is effective in cuttings removal. To benefit from these two actions, a novel configuration of a percussive mechanism was developed to produce an augmenter of rotary drills. The device was called Percussive Augmenter of Rotary Drills (PARoD). A breadboard PARoD was developed with a 6.4 mm (0.25 in) diameter bit and was demonstrated to increase the drilling rate of rotation alone by 1.5 to over 10 times. Further, a large PARoD breadboard with 50.8 mm diameter bit was developed and its tests are currently underway. This paper presents the design, analysis and preliminary test results of the percussive augmenter.

Augmentation of sensory-evoked hemodynamic response in an early Alzheimer's disease mouse model.

PubMed

Kim, Jinho; Jeong, Yong

2013-01-01

Based on enlarged blood oxygen level-dependent (BOLD) responses in cognitively normal subjects at risk for Alzheimer's disease (AD), compensatory neuronal hyperactivation has been proposed as an early marker for diagnosis of AD. The BOLD response results from neurovascular coupling, i.e., hemodynamic response induced by neuronal activity. However, there has been no evidence of task-induced increases in hemodynamic response in animal models of AD. Here, we observed an augmented hemodynamic response pattern in a transgenic AβPP(SWE)/PS1ΔE9 mouse model of AD using three in vivo imaging methods: intrinsic optical signal imaging, multi-photon laser scanning microscopy, and laser Doppler flowmetry. Sensory stimulation resulted in augmented and prolonged hemodynamic responses in transgenic mice evidenced by changes in total, oxygenated, and deoxygenated hemoglobin concentration. This difference between transgenic and wild-type mice was significant at 7 months of age when amyloid plaques and cerebral amyloid angiopathy had developed but not at younger or older ages. Correspondingly, sensory stimulation-induced pial arteriole diameter was also augmented and prolonged in transgenic mice at 7 months of age. Cerebral blood flow response in transgenic mice was augmented but not prolonged. These results are consistent with the existence of BOLD signal hyperactivation in non-demented AD-risk human subjects, supporting its potential use as an early diagnostic marker of AD.

Lipocalin-2 Promotes Endoplasmic Reticulum Stress and Proliferation by Augmenting Intracellular Iron in Human Pulmonary Arterial Smooth Muscle Cells

PubMed Central

Wang, Guoliang; Liu, Shenghua; Wang, Li; Meng, Liukun; Cui, Chuanjue; Zhang, Hao; Hu, Shengshou; Ma, Ning; Wei, Yingjie

2017-01-01

Endoplasmic reticulum (ER) stress, a feature of many conditions associated with pulmonary hypertension (PH), is increasingly recognized as a common response to promote proliferation in the walls of pulmonary arteries. Increased expression of Lipocalin-2 in PH led us to test the hypothesis that Lipocalin-2, a protein known to sequester iron and regulate it intracellularly, might facilitate the ER stress and proliferation in pulmonary arterial smooth muscle cells (PASMCs). In this study, we observed greatly increased Lcn2 expression accompanied with increased ATF6 cleavage in a standard rat model of pulmonary hypertension induced by monocrotaline. In cultured human PASMCs, Lcn2 significantly promoted ER stress (determined by augmented cleavage and nuclear localization of ATF6, up-regulated transcription of GRP78 and NOGO, increased expression of SOD2, and mild augmented mitochondrial membrane potential) and proliferation (assessed by Ki67 staining and BrdU incorporation). Lcn2 promoted ER stress accompanied with augmented intracellular iron levels in human PASMCs. Treatment human PASMCs with FeSO4 induced the similar ER stress and proliferation response and iron chelator (deferoxamine) abrogated the ER stress and proliferation induced by Lcn2 in cultured human PASMCs. In conclusion, Lcn2 significantly promoted human PASMC ER stress and proliferation by augmenting intracellular iron. The up-regulation of Lcn2 probably involved in the pathogenesis and progression of PH. PMID:28255266

Fracture prevention by prophylactic femoroplasty of the proximal femur--metallic compared with cemented augmentation.

PubMed

Springorum, Hans-Robert; Gebauer, Matthias; Mehrl, Alexander; Stark, Olaf; Craiovan, Benjamin; Püschel, Klaus; Amling, Michael; Grifka, Joachim; Beckmann, Johannes

2014-07-01

To compare 2 different femoral neck augmentation techniques at improving the mechanical strength of the femoral neck. Twenty pairs of human cadaveric femora were randomly divided into 2 groups. In 1 group, the femora were augmented with a steel spiral; the other group with the cemented technique. The untreated contralateral side served as an intraindividual control. Fracture strength was evaluated using an established biomechanical testing scenario mimicking a fall on the greater trochanter (Hayes fall). The peak load to failure was significantly higher in the steel spiral group (P = 0.0024) and in the cemented group (P = 0.001) compared with the intraindividual controls. The peak load to failure showed a median of 3167 N (1825-5230 N) in the spiral group and 2485 N (1066-4395 N) in the spiral control group. The peak load to failure in the cemented group was 3698 N (SD ± 1249 N) compared with 2763 N (SD ± 1335 N) in the cement control group. Furthermore, fracture displacement was clearly reduced in the steel spiral group. Femoral augmentations using steel spirals or cement-based femoroplasty are technically feasible procedures. Our results demonstrate that a prophylactic reinforced proximal femur has higher strength when compared with the untreated contralateral limb. Prophylactic augmentation has potential to become an auxiliary treatment option to protect the osteoporotic proximal femur against fracture.

The Potential for Scientific Collaboration in Virtual Ecosystems

ERIC Educational Resources Information Center

Magerko, Brian

2010-01-01

This article explores the potential benefits of creating "virtual ecosystems" from real-world data. These ecosystems are intended to be realistic virtual representations of environments that may be costly or difficult to access in person. They can be constructed as 3D worlds rendered from stereo video data, augmented with scientific data, and then…

Computerized implementation of higher-order electron-correlation methods and their linear-scaling divide-and-conquer extensions.

PubMed

Nakano, Masahiko; Yoshikawa, Takeshi; Hirata, So; Seino, Junji; Nakai, Hiromi

2017-11-05

We have implemented a linear-scaling divide-and-conquer (DC)-based higher-order coupled-cluster (CC) and Møller-Plesset perturbation theories (MPPT) as well as their combinations automatically by means of the tensor contraction engine, which is a computerized symbolic algebra system. The DC-based energy expressions of the standard CC and MPPT methods and the CC methods augmented with a perturbation correction were proposed for up to high excitation orders [e.g., CCSDTQ, MP4, and CCSD(2) TQ ]. The numerical assessment for hydrogen halide chains, polyene chains, and first coordination sphere (C1) model of photoactive yellow protein has revealed that the DC-based correlation methods provide reliable correlation energies with significantly less computational cost than that of the conventional implementations. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Relative receiver autonomous integrity monitoring for future GNSS-based aircraft navigation

NASA Astrophysics Data System (ADS)

Gratton, Livio Rafael

The Global Positioning System (GPS) has enabled reliable, safe, and practical aircraft positioning for en-route and non-precision phases of flight for more than a decade. Intense research is currently devoted to extending the use of Global Navigation Satellite Systems (GNSS), including GPS, to precision approach and landing operations. In this context, this work is focused on the development, analysis, and verification of the concept of Relative Receiver Autonomous Integrity Monitoring (RRAIM) and its potential applications to precision approach navigation. RRAIM fault detection algorithms are developed, and associated mathematical bounds on position error are derived. These are investigated as possible solutions to some current key challenges in precision approach navigation, discussed below. Augmentation systems serving continent-size areas (like the Wide Area Augmentation System or WAAS) allow certain precision approach operations within the covered region. More and better satellites, with dual frequency capabilities, are expected to be in orbit in the mid-term future, which will potentially allow WAAS-like capabilities worldwide with a sparse ground station network. Two main challenges in achieving this goal are (1) ensuring that navigation fault detection functions are fast enough to alert worldwide users of hazardously misleading information, and (2) minimizing situations in which navigation is unavailable because the user's local satellite geometry is insufficient for safe position estimation. Local augmentation systems (implemented at individual airports, like the Local Area Augmentation System or LAAS) have the potential to allow precision approach and landing operations by providing precise corrections to user-satellite range measurements. An exception to these capabilities arises during ionospheric storms (caused by solar activity), when hazardous situations can exist with residual range errors several orders of magnitudes higher than nominal. Until dual frequency civil GPS signals are available, the ability to provide integrity during ionospheric storms, without excessive loss of availability is a major challenge. For all users, with or without augmentation, some situations cause short duration losses of satellites in view. Two examples are aircraft banking during turns and ionospheric scintillation. The loss of range signals can translate into gaps in good satellite geometry, and the resulting challenge is to ensure navigation continuity by bridging these gaps, while simultaneously maintaining high integrity. It is shown that the RRAIM methods developed in this research can be applied to mitigate each of these obstacles to safe and reliable precision aircraft navigation.

Virtual reality to augment robot-assisted gait training in non-ambulatory patients with a subacute stroke: a pilot randomized controlled trial.

PubMed

Bergmann, Jeannine; Krewer, Carmen; Bauer, Petra; Koenig, Alexander; Riener, Robert; Müller, Friedemann

2018-06-01

Active performance is crucial for motor learning, and, together with motivation, is believed to be associated with a better rehabilitation outcome. Virtual reality (VR) is an innovative approach to engage and motivate patients during training. There is promising evidence for its efficiency in retraining upper limb function. However, there is insufficient proof for its effectiveness in gait training. To evaluate the acceptability of robot-assisted gait training (RAGT) with and without VR and the feasibility of potential outcome measures to guide the planning of a larger randomized controlled trial (RCT). Single-blind randomized controlled pilot trial with two parallel arms. Rehabilitation hospital. Twenty subacute stroke patients (64±9 years) with a Functional Ambulation Classification (FAC) ≤2. Twelve sessions (over 4 weeks) of either VR-augmented RAGT (intervention group) or standard RAGT (control group). Acceptability of the interventions (drop-out rate, questionnaire), patients' motivation (Intrinsic Motivation Inventory [IMI], individual mean walking time), and feasibility of potential outcome measures (completion rate and response to interventions) were determined. We found high acceptability of repetitive VR-augmented RAGT. The drop-out rate was 1/11 in the intervention and 4/14 in the control group. Patients of the intervention group spent significantly more time walking in the robot than the control group (per session and total walking time; P<0.03). In both groups, motivation measured with the IMI was high over the entire intervention period. The felt pressure and tension significantly decreased in the intervention group (P<0.01) and was significantly lower than in the control group at the last therapy session (r=-0.66, P=0.005). The FAC is suggested as a potential primary outcome measure for a definitive RCT, as it could be assessed in all patients and showed significant response to interventions (P<0.01). We estimated a sample size of 44 for a future RCT. VR-augmented RAGT resulted in high acceptability and motivation, and in a reduced drop-out rate and an extended training time compared to standard RAGT. This pilot trial provides guidance for a prospective RCT on the effectiveness of VR-augmented RAGT. VR might be a promising approach to enrich and improve gait rehabilitation after stroke.

Experiments on high speed ejectors

NASA Technical Reports Server (NTRS)

Wu, J. J.

1986-01-01

Experimental studies were conducted to investigate the flow and the performance of thrust augmenting ejectors for flight Mach numbers in the range of 0.5 to 0.8, primary air stagnation pressures up to 107 psig (738 kPa), and primary air stagnation temperatures up to 1250 F (677 C). The experiment verified the existence of the second solution ejector flow, where the flow after complete mixing is supersonic. Thrust augmentation in excess of 1.2 was demonstrated for both hot and cold primary jets. The experimental ejector performed better than the corresponding theoretical optimal first solution ejector, where the mixed flow is subsonic. Further studies are required to realize the full potential of the second solution ejector. The research program was started by the Flight Dynamics Research Corporation (FDRC) to investigate the characteristic of a high speed ejector which augments thrust of a jet at high flight speeds.

Equine-derived bone mineral matrix for maxillary sinus floor augmentation: a clinical, radiographic, histologic, and histomorphometric case series.

PubMed

Nevins, Myron; Heinemann, Friedhelm; Janke, Ulrich W; Lombardi, Teresa; Nisand, David; Rocchietta, Isabella; Santoro, Giacomo; Schupbach, Peter; Kim, David M

2013-01-01

The objective of this proof-of-principle multicenter case series was to examine the bone regenerative potential of a newly introduced equine-derived bone mineral matrix (Equimatrix) to provide human sinus augmentation for the purpose of implant placement in the posterior maxilla. There were 10 patients requiring 12 maxillary sinus augmentations enrolled in this study. Histologic results at 6 months demonstrated abundant amounts of vital new bone in intimate contact with residual graft particles. Active bridging between residual graft particles with newly regenerated bone was routinely observed in intact core specimens. A mean value of 23.4% vital bone formation was observed at 6 months. This compared favorably with previous results using xenografts to produce bone in the maxillary sinus for the purpose of dental implant placement. Both the qualitative and quantitative results of this case series suggest comparable bone regenerative results at 6 months to bovine-derived xenografts.

a Framework for Low-Cost Multi-Platform VR and AR Site Experiences

NASA Astrophysics Data System (ADS)

Wallgrün, J. O.; Huang, J.; Zhao, J.; Masrur, A.; Oprean, D.; Klippel, A.

2017-11-01

Low-cost consumer-level immersive solutions have the potential to revolutionize education and research in many fields by providing virtual experiences of sites that are either inaccessible, too dangerous, or too expensive to visit, or by augmenting in-situ experiences using augmented and mixed reality methods. We present our approach for creating low-cost multi-platform virtual and augmented reality site experiences of real world places for education and research purposes, making extensive use of Structure-from-Motion methods as well as 360° photography and videography. We discuss several example projects, for the Mayan City of Cahal Pech, Iceland's Thrihnukar volcano, the Santa Marta informal settlement in Rio, and for the Penn State Campus, and we propose a framework for creating and maintaining such applications by combining declarative content specification methods with a central linked-data based spatio-temporal information system.

ChemPreview: an augmented reality-based molecular interface.

PubMed

Zheng, Min; Waller, Mark P

2017-05-01

Human computer interfaces make computational science more comprehensible and impactful. Complex 3D structures such as proteins or DNA are magnified by digital representations and displayed on two-dimensional monitors. Augmented reality has recently opened another door to access the virtual three-dimensional world. Herein, we present an augmented reality application called ChemPreview with the potential to manipulate bio-molecular structures at an atomistic level. ChemPreview is available at https://github.com/wallerlab/chem-preview/releases, and is built on top of the Meta 1 platform https://www.metavision.com/. ChemPreview can be used to interact with a protein in an intuitive way using natural hand gestures, thereby making it appealing to computational chemists or structural biologists. The ability to manipulate atoms in real world could eventually provide new and more efficient ways of extracting structural knowledge, or designing new molecules in silico. Copyright © 2017 Elsevier Inc. All rights reserved.

Eotaxin Augments Calcification in Vascular Smooth Muscle Cells.

PubMed

Raghuraman, Gayatri; Hsiung, Joseph; Zuniga, Mary C; Baughman, Brittanie D; Hitchner, Elizabeth; Guzman, Raul J; Zhou, Wei

2017-03-01

Calcification of atherosclerotic plaques in elderly patients represents a potent risk marker of cardiovascular events. Plasma analyses of patients with or without calcified plaques reveal significant differences in chemokines, particularly eotaxin, which escalates with increased calcification. We therefore, hypothesize that eotaxin in circulation augments calcification of vascular smooth muscle cells (VSMCs) possibly via oxidative stress in the vasculature. We observe that eotaxin increases the rate of calcification significantly in VSMCs as evidenced by increased alkaline phosphatase activity, calcium deposition, and osteogenic marker expression. In addition, eotaxin promotes proliferation in VSMCs and triggers oxidative stress in a NADPH oxidase dependent manner. These primary novel observations support our proposition that in the vasculature eotaxin augments mineralization. Our findings suggest that eotaxin may represent a potential therapeutic target for prevention of cardiovascular complications in the elderly. J. Cell. Biochem. 118: 647-654, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

CRUX: a Compliant Robotic Upper-Extremity eXosuit for Lightweight, Portable, Multi-DoF Muscular Augmentation

NASA Technical Reports Server (NTRS)

Lessard, Steven; Pansodtee, Pattawong; Robbins, Ash; Baltaxe-Admony, Leya Breanna; Teodorescu, Mircea; Kurniawan,Sri; Agogino, Adrian; Kurniawan, Sri

2017-01-01

Wearable robots can potentially offer their users enhanced stability and strength. These augmentations are ideally designed to actuate harmoniously with the users movements and provide extra force as needed. The creation of such robots, however, is particularly challenging due to the complexity of the underlying human body. In this paper, we present a compliant, robotic exosuit for upper-extremities called CRUX. This exosuit, inspired by tensegrity models of the human arm, features a lightweight (1.3 kg), flexible design for portability. We also show how CRUX maintains full flexibility of the upper-extremities for its users while providing multi- DoF augmentative strength to the major muscles of the arm, as evident by tracking the heart rate of an individual exercising said arm. Exosuits such as CRUX may be useful in physical therapy and in extreme environments where users are expected to exert their bodies to the fullest extent.

Enhancing a Multi-body Mechanism with Learning-Aided Cues in an Augmented Reality Environment

NASA Astrophysics Data System (ADS)

Singh Sidhu, Manjit

2013-06-01

Augmented Reality (AR) is a potential area of research for education, covering issues such as tracking and calibration, and realistic rendering of virtual objects. The ability to augment real world with virtual information has opened the possibility of using AR technology in areas such as education and training as well. In the domain of Computer Aided Learning (CAL), researchers have long been looking into enhancing the effectiveness of the teaching and learning process by providing cues that could assist learners to better comprehend the materials presented. Although a number of works were done looking into the effectiveness of learning-aided cues, but none has really addressed this issue for AR-based learning solutions. This paper discusses the design and model of an AR based software that uses visual cues to enhance the learning process and the outcome perception results of the cues.

First-principles energy band calculation of Ruddlesden–Popper compound Sr{sub 3}Sn{sub 2}O{sub 7} using modified Becke–Johnson exchange potential

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kamimura, Sunao, E-mail: kamimura-sunao@che.kyutech.ac.jp; National Institute of Advanced Industrial Science and Technology; Department of Molecular and Material Sciences, Interdisciplinary Graduate School of Engineering Science, Kyushu University, 6-1 Kasuga Kouen, Kasuga, Fukuoka 816-8580 Japan

The electronic structure of Sr{sub 3}Sn{sub 2}O{sub 7} is evaluated by the scalar-relativistic full potential linearized augmented plane wave (FLAPW+lo) method using the modified Becke–Johnson potential (Tran–Blaha potential) combined with the local density approximation correlation (MBJ–LDA). The fundamental gap between the valence band (VB) and conduction band (CB) is estimated to be 3.96 eV, which is close to the experimental value. Sn 5s states and Sr 4d states are predominant in the lower and upper CB, respectively. On the other hand, the lower VB is mainly composed of Sn 5s, 5p, and O 2p states, while the upper VB mainlymore » consists of O 2p states. These features of the DOS are well reflected by the optical transition between the upper VB and lower CB, as seen in the energy dependence of the dielectric function. Furthermore, the absorption coefficient estimated from the MBJ–LDA is similar to the experimental result. - Graphical abstract: Calculated energy band structure along the symmetry lines of the first BZ of Sr{sub 3}Sn{sub 2}O{sub 7} crystal obtained using the MBJ potential. - Highlights: • Electronic structure of Sr{sub 3}Sn{sub 2}O{sub 7} is calculated on the basis of MBJ–LDA method for the first time. • Band gap of Sr{sub 3}Sn{sub 2}O{sub 7} is determined accurately on the basis of MBJ–LDA method. • The experimental absorption spectrum of Sr{sub 3}Sn{sub 2}O{sub 7} produced by MBJ–LDA is more accurate than that obtained by GGA method.« less

Directing driver attention with augmented reality cues

PubMed Central

Rusch, Michelle L.; Schall, Mark C.; Gavin, Patrick; Lee, John D.; Dawson, Jeffrey D.; Vecera, Shaun; Rizzo, Matthew

2013-01-01

This simulator study evaluated the effects of augmented reality (AR) cues designed to direct the attention of experienced drivers to roadside hazards. Twenty-seven healthy middle-aged licensed drivers with a range of attention capacity participated in a 54 mile (1.5 hour) drive in an interactive fixed-base driving simulator. Each participant received AR cues to potential roadside hazards in six simulated straight (9 mile long) rural roadway segments. Drivers were evaluated on response time for detecting a potentially hazardous event, detection accuracy for target (hazard) and non-target objects, and headway with respect to the hazards. Results showed no negative outcomes associated with interference. AR cues did not impair perception of non-target objects, including for drivers with lower attentional capacity. Results showed near significant response time benefits for AR cued hazards. AR cueing increased response rate for detecting pedestrians and warning signs but not vehicles. AR system false alarms and misses did not impair driver responses to potential hazards. PMID:24436635

A Nonlinear Dynamic Inversion Predictor-Based Model Reference Adaptive Controller for a Generic Transport Model

NASA Technical Reports Server (NTRS)

Campbell, Stefan F.; Kaneshige, John T.

2010-01-01

Presented here is a Predictor-Based Model Reference Adaptive Control (PMRAC) architecture for a generic transport aircraft. At its core, this architecture features a three-axis, non-linear, dynamic-inversion controller. Command inputs for this baseline controller are provided by pilot roll-rate, pitch-rate, and sideslip commands. This paper will first thoroughly present the baseline controller followed by a description of the PMRAC adaptive augmentation to this control system. Results are presented via a full-scale, nonlinear simulation of NASA s Generic Transport Model (GTM).

Space-based communications infrastructure for developing countries

NASA Astrophysics Data System (ADS)

Barker, Keith; Barnes, Carl; Price, K. M.

1995-08-01

This study examines the potential use of satellites to augment the telecommunications infrastructure of developing countries with advanced satellites. The study investigated the potential market for using satellites in developing countries, the role of satellites in national information infrastructures (NII), the technical feasibility of augmenting NIIs with satellites, and a nation's financial conditions necessary for procuring satellite systems. In addition, the study examined several technical areas including onboard processing, intersatellite links, frequency of operation, multibeam and active antennas, and advanced satellite technologies. The marketing portion of this study focused on three case studies: China, Brazil, and Mexico. These cases represent countries in various stages of telecommunication infrastructure development. The study concludes by defining the needs of developing countries for satellites, and recommends steps that both industry and NASA can take to improve the competitiveness of U.S. satellite manufacturing.

Space-based Communications Infrastructure for Developing Countries

NASA Technical Reports Server (NTRS)

Barker, Keith; Barnes, Carl; Price, K. M.

1995-01-01

This study examines the potential use of satellites to augment the telecommunications infrastructure of developing countries with advanced satellites. The study investigated the potential market for using satellites in developing countries, the role of satellites in national information infractructures (NII), the technical feasibility of augmenting NIIs with satellites, and a nation's financial conditions necessary for procuring satellite systems. In addition, the study examined several technical areas including onboard processing, intersatellite links, frequency of operation, multibeam and active antennas, and advanced satellite technologies. The marketing portion of this study focused on three case studies: China, Brazil, and Mexico. These cases represent countries in various stages of telecommunication infrastructure development. The study concludes by defining the needs of developing countries for satellites, and recommends steps that both industry and NASA can take to improve the competitiveness of U.S. satellite manufacturing.

Augmentation of Water Resources Potential and Cropping Intensification Through Watershed Programs.

PubMed

Mondal, Biswajit; Singh, Alka; Singh, S D; Kalra, B S; Samal, P; Sinha, M K; Ramajayam, D; Kumar, Suresh

2018-02-01

  This paper presents the biophysical impact of various interventions made under watershed development programs, in terms of the creation of additional water resources, and resultant changes in land use and cropping patterns in the Bundelkhand region of Madhya Pradesh State, India. Both primary and secondary data gathered from randomly selected watersheds and their corresponding control villages were used in this study. Analysis revealed that emphasis was given primarily to the creation of water resources potential during implementation of the programs, which led to augmentation of surface and groundwater availability for both irrigation and non-agricultural purposes. In addition, other land based interventions for soil and moisture conservation, plantation activities, and so forth, were taken up on both arable and nonarable land, which helped to improve land slope and land use, cropping pattern, agricultural productivity, and vegetation cover.

The Mobility and Dispersal of Augmented Gravel in Upland Channels: a Knowledge-limited Practise in Supply-limited Channels

NASA Astrophysics Data System (ADS)

Downs, P. W.; Gilvear, D. J.

2017-12-01

Most river restoration research has been directed at rivers in the highly populated alluvial lowlands: significantly less is known about effectively rehabilitating upland channels, in part because the dynamics of sediment transfer are less well understood. Upland gravel augmentation is thus both a somewhat unproven method for rehabilitating degraded aquatic habitats in sediment-poor reaches, but also a natural experiment in better understanding sediment dynamics in steep, hydraulically-complex river channels. Monitoring on the River Avon in SW England since Water Year (WY) 2015 uses seismic impact plates, RFID-tagged particles and detailed channel bed mapping to establish the mobility rates of augmented particles, their dispersal distances and settling locations relative to flows received. Particles are highly, and equally, mobile: in WY2015, 17 sub-bankfull flows moved at least 60% of augmented particles with volumetric movement non-linearly correlated to flow energy but not to particle size. Waning rates of transport over the year suggest supply limitations. This relationship breaks down early in WY2017 where a two-year flow event moved 40% of the particles in just two months - confounding factors may include particle mass differences and particle supplies from upstream. Median particle travel distances correlate well to energy applied and suggest a long-tailed fan of dispersal with supplemental controls including channel curvature, boulder presence and stream power. Locally, particles are deposited preferentially around boulders and in sheltered river margins but also perched in clusters above the low-flow channel. High tracer mobility makes median transport distances highly dependent on the survey length - in WY2017 some particles travelled 300 m in a 3-month period that included the two-year flood event. Further, in WY2017 median transport distance as a function of volumetric transport suggested significant transport beyond the target reach. The observed particle dynamics thus have implications both for the biological effectiveness of gravel augmentation and the efficacy criterion of `minimum mobility'. They also reflect the challenges inherent to constraint-limited natural experiments that are, conversely, important in proving the value of geomorphology to resource managers.

Augmented Reality for Searching Potential Assets in Medan using GPS based Tracking

NASA Astrophysics Data System (ADS)

Muchtar, M. A.; Syahputra, M. F.; Syahputra, N.; Ashrafia, S.; Rahmat, R. F.

2017-01-01

Every city is required to introduce its variety of potential assets so that the people know how to utilize or to develop their area. Potential assets include infrastructure, facilities, people, communities, organizations, customs that affects the characteristics and the way of life in Medan. Due to lack of socialization and information, most of people in Medan only know a few parts of the assets. Recently, so many mobile apps provide search and mapping locations used to find the location of potential assets in user’s area. However, the available information, such as text and digital maps, sometimes do not much help the user clearly and dynamically. Therefore, Augmented Reality technology able to display information in real world vision is implemented in this research so that the information can be more interactive and easily understood by user. This technology will be implemented in mobile apps using GPS based tracking and define the coordinate of user’s smartphone as a marker so that it can help people dynamically and easily find the location of potential assets in the nearest area based on the direction of user’s view on camera.

Pulmonary Vascular Response Patterns During Exercise in Left Ventricular Systolic Dysfunction Predict Exercise Capacity and Outcomes

PubMed Central

Lewis, Gregory D.; Murphy, Ryan M.; Shah, Ravi V.; Pappagianopoulos, Paul P.; Malhotra, Rajeev; Bloch, Kenneth D.; Systrom, David M.; Semigran, Marc J.

2012-01-01

Background Elevated resting pulmonary arterial pressure (PAP) in patients with left ventricular systolic dysfunction (LVSD) purports a poor prognosis. However, PAP response patterns to exercise in LVSD and their relationship to functional capacity and outcomes have not been characterized. Methods and Results Sixty consecutive patients with LVSD (age 60±12 years, LV ejection fraction 0.31±0.07, mean±SD) and 19 controls underwent maximum incremental cardiopulmonary exercise testing with simultaneous hemodynamic monitoring. During low-level exercise (30 Watts), LVSD subjects compared to controls, had greater augmentation in mean PAPs (15±1 vs. 5±1 mmHg), transpulmonary gradients (5±1 vs. 1±1 mmHg), and effective PA elastance (0.05±0.02 vs. −0.03±0.01 mmHg/ml, p<0.0001 for all). A linear increment in PAP relative to work (0.28±0.12 mmHg/watt) was observed in 65% of LVSD patients, which exceeded that observed in controls (0.07±0.02 mmHg/watt, P<0.0001). Exercise capacity and survival was worse in patients with a PAP/watt slope above the median than in patients with a lower slope. In the remaining 35% of LVSD patients, exercise induced a steep initial increment in PAP (0.41±0.16 mmHg/watt) followed by a plateau. The plateau pattern, compared to a linear pattern, was associated with reduced peak VO2 (10.6±2.6 vs. 13.1±4.0 ml/kg/min, P=0.005), lower right ventricular stroke work index augmentation with exercise (5.7±3.8 vs. 9.7±5.0 g/m2, P=0.002), and increased mortality (HR 8.1, 95% CI 2.7-23.8, P<0.001). Conclusions A steep increment in PAP during exercise and failure to augment PAP throughout exercise are associated with decreased exercise capacity and survival in patients with LVSD, and may therefore represent therapeutic targets. Clinical Trial Information URL: http://www.clinicaltrials.gov. Unique Identifier: NCT00309790) PMID:21292991

Laser Scanner Technology, Ground-Penetrating Radar and Augmented Reality for the Survey and Recovery of Artistic, Archaeological and Cultural Heritage

NASA Astrophysics Data System (ADS)

Barrile, V.; Bilotta, G.; Meduri, G. M.; De Carlo, D.; Nunnari, A.

2017-11-01

In this study, using technologies such as laser scanner and GPR it was desired to see their potential in the cultural heritage. Also with regard to the processing part we are compared the results obtained by the various commercial software and algorithms developed and implemented in Matlab. Moreover, Virtual Reality and Augmented Reality allow integrating the real world with historical-artistic information, laser scanners and georadar (GPR) data and virtual objects, virtually enriching it with multimedia elements, graphic and textual information accessible through smartphones and tablets.

Topiramate augmentation in clozapine-treated patients with schizophrenia: clinical and metabolic effects.

PubMed

Hahn, Margaret K; Remington, Gary; Bois, Daniel; Cohn, Tony

2010-12-01

Clozapine represents the treatment of choice for refractory psychosis, although a significant number of individuals demonstrate suboptimal response to it as well, leading to clozapine augmentation strategies. A variety of agents have been investigated in this regard, including mood stabilizers, such as anticonvulsants. Within this group of medications, topiramate is unique in that it is associated with weight loss, making it an attractive option because of clozapine's notable risk for associated metabolic disturbance. A 12-week naturalistic, open study was carried out to examine the potential benefits of topiramate in clozapine-treated individuals with schizophrenia demonstrating a suboptimal clinical response. We were specifically interested in clinical symptoms, changes in metabolic parameters, and tolerability. A total of 20 subjects were enrolled, and 16 completed the study, including 5 individuals with type 2 diabetes. Topiramate augmentation led to a 14% improvement in total Brief Psychiatric Rating Scale scores (P = 0.0003), a 2.5% decrease in body weight (P = 0.015), and was generally well tolerated, paraesthesia being the most common side effect. These findings support topiramate as a viable augmentation strategy in clozapine partial responders, with evidence of both clinical and metabolic benefits.

Bio-augmentation and nutrient amendment decrease concentration of mercury in contaminated soil.

PubMed

Mahbub, Khandaker Rayhan; Krishnan, Kannan; Andrews, Stuart; Venter, Henrietta; Naidu, Ravi; Megharaj, Mallavarapu

2017-01-15

Four mercury (Hg) contaminated soils with different pH (7.6, 8.5, 4.2 and 7.02) and total organic carbon contents (2.1, 2.2, 4 and 0.9%) were subjected to bioremediation utilizing a Hg volatilizing bacterial strain Sphingobium SA2 and nutrient amendment. In a field with ~280mg/kgHg, 60% of Hg was removed by bio-augmentation in 7days, and the removal was improved when nutrients were added. Whereas in artificially spiked soils, with ~100mg/kgHg, removal due to bio-augmentation was 33 to 48% in 14days. In the field contaminated soil, nutrient amendment alone without bio-augmentation removed 50% of Hg in 28days. Nutrient amendment also had an impact on Hg remediation in the spiked soils, but the best results were obtained when the strain and nutrients both were applied. The development of longer root lengths from lettuce and cucumber seeds grown in the remediated soils confirmed that the soil quality improved after bioremediation. This study clearly demonstrates the potential of Hg-reducing bacteria in remediation of Hg-contaminated soils. However, it is desirable to trap the volatilized Hg for enhanced bioremediation. Copyright © 2016 Elsevier B.V. All rights reserved.

The Extended Direct Anterior Approach for Column Augmentation in the Deficient Pelvis: A Novel Surgical Technique, and Case Series Report.

PubMed

Spanyer, Jonathon M; Beaumont, Christopher M; Yerasimides, Jonathan G

2017-02-01

Anterior column deficiency of the pelvis may pose a serious threat to the stability of the acetabular component after total hip arthroplasty and, thus, jeopardize the overall success of the procedure. After Institutional Review Board approval, a retrospective review was undertaken to identify all patients undergoing revision total hip arthroplasty with anterior column augmentation through an extended direct anterior approach. Demographics and surgical details were collected, and subjects were followed for a 2-year minimum period to measure patient outcomes and to evaluate for the stability of construct fixation. A novel surgical procedure description was provided and supplemented with an illustrative case example. At 2 years post augmentation, patients had favorable functional outcomes with radiologic evidence of stable fixation. Proximal extension of the direct anterior approach to the hip can facilitate anterior column access and augmentation to improve stability of the hip reconstruction. This treatment may be an alternative to spanning constructs such as cup-cage constructs and custom implants, affording the potential for long-term biologic fixation. Further investigation into this technique is warranted. Copyright © 2016 Elsevier Inc. All rights reserved.

Distinct Mechanisms Underlie Boosted Polysaccharide-Specific IgG Responses Following Secondary Challenge with Intact Gram-Negative versus Gram-Positive Extracellular Bacteria.

PubMed

Kar, Swagata; Arjunaraja, Swadhinya; Akkoyunlu, Mustafa; Pier, Gerald B; Snapper, Clifford M

2016-06-01

Priming of mice with intact, heat-killed cells of Gram-negative Neisseria meningitidis, capsular serogroup C (MenC) or Gram-positive group B Streptococcus, capsular type III (GBS-III) bacteria resulted in augmented serum polysaccharide (PS)-specific IgG titers following booster immunization. Induction of memory required CD4(+) T cells during primary immunization. We determined whether PS-specific memory for IgG production was contained within the B cell and/or T cell populations, and whether augmented IgG responses following booster immunization were also dependent on CD4(+) T cells. Adoptive transfer of purified B cells from MenC- or GBS-III-primed, but not naive mice resulted in augmented PS-specific IgG responses following booster immunization. Similar responses were observed when cotransferred CD4(+) T cells were from primed or naive mice. Similarly, primary immunization with unencapsulated MenC or GBS-III, to potentially prime CD4(+) T cells, failed to enhance PS-specific IgG responses following booster immunization with their encapsulated isogenic partners. Furthermore, in contrast to GBS-III, depletion of CD4(+) T cells during secondary immunization with MenC or another Gram-negative bacteria, Acinetobacter baumannii, did not inhibit augmented PS-specific IgG booster responses of mice primed with heat-killed cells. Also, in contrast with GBS-III, booster immunization of MenC-primed mice with isolated MenC-PS, a TI Ag, or a conjugate of MenC-PS and tetanus toxoid elicited an augmented PS-specific IgG response similar to booster immunization with intact MenC. These data demonstrate that memory for augmented PS-specific IgG booster responses to Gram-negative and Gram-positive bacteria is contained solely within the B cell compartment, with a differential requirement for CD4(+) T cells for augmented IgG responses following booster immunization. Copyright © 2016 by The American Association of Immunologists, Inc.

A prospective, randomized pilot study on the safety and efficacy of recombinant human growth and differentiation factor-5 coated onto β-tricalcium phosphate for sinus lift augmentation.

PubMed

Koch, Felix P; Becker, Jürgen; Terheyden, Hendrik; Capsius, Björn; Wagner, Wilfried

2010-11-01

The aim of this prospective, randomized clinical trial was to investigate the potential of recombinant human growth and differentiation factor-5 (rhGDF-5) coated onto β-tricalcium phosphate (β-TCP) (rhGDF-5/β-TCP) to support bone formation after sinus lift augmentation. In total, 31 patients participated in this multicenter clinical trial. They required a two-stage unilateral maxillary sinus floor augmentation (residual bone height <5 mm). According to a parallel-group design, the patients were randomized to three treatment groups: (a) augmentation with rhGDF-5/β-TCP and a 3-month healing period, (b) augmentation with rhGDF-5/β-TCP and a 4-month healing period and (c) medical device β-TCP mixed with autologous bone and a 4-month healing period. The primary study objective was the area of newly formed bone within the augmented area as assessed by histomorphometric evaluation of trephine bur biopsies. The osseous regeneration was similar in each treatment group; the amount of newly formed bone ranged between 28% (± 15.5%) and 31.8% (± 17.9%). Detailed analysis of histological data will be published elsewhere. As secondary efficacy variables, the augmentation height at the surgery site was measured by radiography. The largest augmentation was radiologically achieved in the rhGDF-5/β-TCP - 3-month and the rhGDF-5/β-TCP - 4-month treatment groups. As safety parameters, adverse events were recorded and anti-drug antibody levels were evaluated. Most of the adverse events were judged as unrelated to the study medication. Four out of 47 (8.5%) implants failed in patients treated with rhGDF-5/β-TCP, a result that is in agreement with the general implant failure rate of 5-15%. Transiently very low amounts of anti-rhGDF-5 antibodies were detected in some patients who received rhGDF-5, which was not related to the bone formation outcome. rhGDF-5/β-TCP was found to be effective and safe as the control treatment with autologous bone mixed β-TCP in sinus floor augmentation. Thus, further investigation regarding efficacy and safety will be carried out in larger patient populations. © 2010 John Wiley & Sons A/S.

Regulatory domain phosphorylation to distinguish the mechanistic basis underlying acute CFTR modulators

PubMed Central

Pyle, Louise C.; Ehrhardt, Annette; Mitchell, Lisa High; Fan, LiJuan; Ren, Aixia; Naren, Anjaparavanda P.; Li, Yao; Clancy, J. P.; Bolger, Graeme B.; Sorscher, Eric J.

2011-01-01

Modulator compounds intended to overcome disease-causing mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) show significant promise in clinical testing for cystic fibrosis. However, the mechanism(s) of action underlying these compounds are not fully understood. Activation of CFTR ion transport requires PKA-regulated phosphorylation of the regulatory domain (R-D) and dimerization of the nucleotide binding domains. Using a newly developed assay, we evaluated nine compounds including both CFTR potentatiators and activators discovered via various high-throughput screening strategies to acutely augment CFTR activity. We found considerable differences in the effects on R-D phosphorylation. Some (including UCCF-152) stimulated robust phosphorylation, and others had little effect (e.g., VRT-532 and VX-770). We then compared CFTR activation by UCCF-152 and VRT-532 in Ussing chamber studies using two epithelial models, CFBE41o− and Fischer rat thyroid cells, expressing various CFTR forms. UCCF-152 activated wild-type-, G551D-, and rescued F508del-CFTR currents but did not potentiate cAMP-mediated CFTR activation. In contrast, VRT-532 moderately activated CFTR short-circuit current and strongly potentiated forskolin-mediated current. Combined with the result that UCCF-152, but not VRT-532 or VX-770, acts by increasing CFTR R-D phosphorylation, these findings indicate that potentiation of endogenous cAMP-mediated activation of mutant CFTR is not due to a pathway involving augmented R-D phosphorylation. This study presents an assay useful to distinguish preclinical compounds by a crucial mechanism underlying CFTR activation, delineates two types of compound able to acutely augment CFTR activity (e.g., activators and potentiators), and demonstrates that a number of different mechanisms can be successfully employed to activate mutant CFTR. PMID:21724857

Development of functional composts using spent coffee grounds, poultry manure and biochar through microbial bioaugmentation.

PubMed

Emmanuel, S Aalfin; Yoo, Jangyeon; Kim, Eok-Jo; Chang, Jae-Soo; Park, Young-In; Koh, Sung-Cheol

2017-11-02

Spent coffee grounds (SCG), poultry manure, and agricultural waste-derived biochar were used to manufacture functional composts through microbial bioaugmentation. The highest yield of tomato stalk-based biochar (40.7%) was obtained at 450°C with a surface area of 2.35 m 2 g -1 . Four pilot-scale composting reactors were established to perform composting for 45 days. The ratios of NH 4 + -N/NO 3 - -N, which served as an indicator of compost maturity, indicate rapid, and successful composting via microbial bioaugmentation and biochar amendment. Moreover, germination indices for radish also increased by 14-34% through augmentation and biochar amendment. Microbial diversity was also enhanced in the augmented and biochar-amended composts by 7.1-8.9%, where two species of Sphingobacteriaceae were dominant (29-43%). The scavenging activities of 2,2-diphenyl-1-picrylhydrazyl (DPPH) were enhanced by 14.1% and 8.6% in the fruits of pepper plants grown in the presence of the TR-2 (augmentation applied only) and TR-3 (both augmentation and biochar amendment applied) composts, respectively. Total phenolic content was also enhanced by 68% in the fruits of the crops grown in TR-3. Moreover, the other compost, TR-L (augmentation applied only), boosted DPPH scavenging activity by 111% in leeks compared with commercial organic fertilizer, while TR-3 increased the phenolic content by 44.8%. Composting facilitated by microbial augmentation and biochar amendment shortened the composting time and enhanced the quality of the functional compost. These results indicate that functional compost has great potential to compete with commercially available organic fertilizers and that the novel composting technology could significantly contribute to the eco-friendly recycling of organic wastes such as spent coffee grounds, poultry manure, and agricultural wastes.

Flashback Detection Sensor for Hydrogen Augmented Natural Gas Combustion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thornton, J.D.; Chorpening, B.T.; Sidwell, T.

2007-05-01

The use of hydrogen augmented fuel is being investigated by various researchers as a method to extend the lean operating limit, and potentially reduce thermal NOx formation in natural gas fired lean premixed (LPM) combustion systems. The resulting increase in flame speed during hydrogen augmentation, however, increases the propensity for flashback in LPM systems. Real-time in-situ monitoring of flashback is important for the development of control strategies for use of hydrogen augmented fuel in state-of-the-art combustion systems, and for the development of advanced hydrogen combustion systems. The National Energy Technology Laboratory (NETL) and Woodward Industrial Controls are developing a combustionmore » control and diagnostics sensor (CCADS), which has already been demonstrated as a useful sensor for in-situ monitoring of natural gas combustion, including detection of important combustion events such as flashback and lean blowoff. Since CCADS is a flame ionization sensor technique, the low ion concentration produced in pure hydrogen combustion raises concerns of whether CCADS can be used to monitor flashback in hydrogen augmented combustion. This paper discusses CCADS tests conducted at 0.2-0.6 MPa (2-6 atm), demonstrating flashback detection with fuel compositions up to 80% hydrogen (by volume) mixed with natural gas. NETL’s Simulation Validation (SimVal) combustor offers full optical access to pressurized combustion during these tests. The CCADS data and high-speed video show the reaction zone moves upstream into the nozzle as the hydrogen fuel concentration increases, as is expected with the increased flame speed of the mixture. The CCADS data and video also demonstrate the opportunity for using CCADS to provide the necessary in-situ monitor to control flashback and lean blowoff in hydrogen augmented combustion applications.« less

Functional Redundancy Between Canonical Endocannabinoid Signaling Systems in the Modulation of Anxiety.

PubMed

Bedse, Gaurav; Hartley, Nolan D; Neale, Emily; Gaulden, Andrew D; Patrick, Toni A; Kingsley, Philip J; Uddin, Md Jashim; Plath, Niels; Marnett, Lawrence J; Patel, Sachin

2017-10-01

Increasing the available repertoire of effective treatments for mood and anxiety disorders represents a critical unmet need. Pharmacological augmentation of endogenous cannabinoid (eCB) signaling has been suggested to represent a novel approach to the treatment of anxiety disorders; however, the functional interactions between two canonical eCB pathways mediated via anandamide (N-arachidonylethanolamine [AEA]) and 2-arachidonoylglycerol (2-AG) in the regulation of anxiety are not well understood. We utilized pharmacological augmentation and depletion combined with behavioral and electrophysiological approaches to probe the role of 2-AG signaling in the modulation of stress-induced anxiety and the functional redundancy between AEA and 2-AG signaling in the modulation of anxiety-like behaviors in mice. Selective 2-AG augmentation reduced anxiety in the light/dark box assay and prevented stress-induced increases in anxiety associated with limbic AEA deficiency. In contrast, acute 2-AG depletion increased anxiety-like behaviors, which was normalized by selective pharmacological augmentation of AEA signaling and via direct cannabinoid receptor 1 stimulation with Δ 9 -tetrahydrocannabinol. Electrophysiological studies revealed 2-AG modulation of amygdala glutamatergic transmission as a key synaptic correlate of the anxiolytic effects of 2-AG augmentation. Although AEA and 2-AG likely subserve distinct physiological roles, a pharmacological and functional redundancy between these canonical eCB signaling pathways exists in the modulation of anxiety-like behaviors. These data support development of eCB-based treatment approaches for mood and anxiety disorders and suggest a potentially wider therapeutic overlap between AEA and 2-AG augmentation approaches than was previously appreciated. Copyright © 2017 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Insulin treatment augments KCNQ1/KCNE1 currents but not KCNQ1 currents, which is associated with an increase in KCNE1 expression.

PubMed

Wu, Minghua; Obara, Yutaro; Ohshima, Shingo; Nagasawa, Yoshinobu; Ishii, Kuniaki

2017-11-04

Diabetes mellitus affects ion channel physiology. We have previously reported that acute application of insulin suppresses the KCNQ1/KCNE1 currents that play an important role in terminating ventricular action potential. In this study, we investigated the effect of long-term insulin treatment on KCNQ1/KCNE1 currents using the Xenopus oocyte expression system. Insulin treatment with a duration longer than 6 h had an opposite effect to acute insulin application, that is, it augmented the KCNQ1/KCNE1 currents. Inhibitors of PI3K, wortmannin and LY294002, and a MEK inhibitor, U0126, abolished the potentiating effect of long-term insulin treatment. The long-term treatment with insulin had no effect on KCNQ1 currents indicating an essential role of KCNE1 in the insulin effect, which is similar to the acute insulin effect. Cycloheximide, an inhibitor of protein synthesis, and brefeldin A, an inhibitor of protein transport from endoplasmic reticulum, suppressed the long-term insulin effect. Western blotting analysis combined with these pharmacological data suggest that long-term insulin treatment augments KCNQ1/KCNE1 currents by increasing KCNE1 protein expression. Copyright © 2017 Elsevier Inc. All rights reserved.

The role of selective estrogen receptor modulators in the treatment of schizophrenia.

PubMed

Bratek, Agnieszka; Krysta, Krzysztof; Drzyzga, Karolina; Barańska, Justyna; Kucia, Krzysztof

2016-09-01

Gender differences in schizophrenia have been recognized for a long time and it has been widely accepted that sex steroid hormones, especially estradiol, are strongly attributed to this fact. Two hypotheses regarding estradiol action in psychoses gained special research attention - the estrogen protection hypothesis and hypoestrogenism hypothesis. A growing number of studies have shown benefits in augmenting antipsychotic treatment with estrogens or selective estrogen receptor modulators (SERM). This review is focused on the role of selective estrogen receptor modulators in the treatment of schizophrenic patients. In order to achieve this result PubMed was searched using the following terms: schizophrenia, raloxifene, humans. We reviewed only randomized, placebo-controlled studies. Raloxifene, a selective estrogen receptor modulator was identified as useful to improve negative, positive, and general psychopathological symptoms, and also cognitive functions. All reviewed studies indicated improvement in at least one studied domain. Augmentation with raloxifene was found to be a beneficial treatment strategy for chronic schizophrenia both in female and male patients, however potential side effects (a small increase in the risk of venous thromboembolism and endometrial cancer) should be carefully considered. SERMs could be an effective augmentation strategy in the treatment of both men women with schizophrenia, although further research efforts are needed to study potential long-term side effects.

Communication and team situation awareness in the OR: Implications for augmentative information display.

PubMed

Parush, Avi; Kramer, Chelsea; Foster-Hunt, Tara; Momtahan, Kathryn; Hunter, Aren; Sohmer, Benjamin

2011-06-01

Team Situation Awareness (TSA) is one of the critical factors in effective Operating Room (OR) teamwork and can impact patient safety and quality of care. While previous research showed a relationship between situation awareness, as measured by communication events, and team performance, the implications for developing technology to augment and facilitate TSA were not examined. This research aims to further study situation-related communications in the cardiac OR in order to uncover potential degradation in TSA which may lead to adverse events. The communication loop construct-the full cycle of information flow between the participants in the sequence-was used to assess susceptibility to breakdown. Previous research and the findings here suggest that communication loops that are open, non-directed, or with delayed closure, can be susceptible to information loss. These were quantitatively related to communication indicators of TSA such as questions, replies, and announcements. Taken together, both qualitative and quantitative analyses suggest that a high proportion of TSA-related communication (63%) can be characterized as susceptible to information loss. The findings were then used to derive requirements and design a TSA augmentative display. The design principles and potential benefits of such a display are outlined and discussed. Copyright © 2010 Elsevier Inc. All rights reserved.

Histone deacetylase inhibitors augment doxorubicin-induced DNA damage in cardiomyocytes.

PubMed

Ververis, Katherine; Rodd, Annabelle L; Tang, Michelle M; El-Osta, Assam; Karagiannis, Tom C

2011-12-01

Histone deacetylase inhibitors have emerged as a new class of anticancer therapeutics with suberoylanilide hydroxamic acid (Vorinostat) and depsipeptide (Romidepsin) already being approved for clinical use. Numerous studies have identified that histone deacetylase inhibitors will be most effective in the clinic when used in combination with conventional cancer therapies such as ionizing radiation and chemotherapeutic agents. One promising combination, particularly for hematologic malignancies, involves the use of histone deacetylase inhibitors with the anthracycline, doxorubicin. However, we previously identified that trichostatin A can potentiate doxorubicin-induced hypertrophy, the dose-limiting side-effect of the anthracycline, in cardiac myocytes. Here we have the extended the earlier studies and evaluated the effects of combinations of the histone deacetylase inhibitors, trichostatin A, valproic acid and sodium butyrate on doxorubicin-induced DNA double-strand breaks in cardiomyocytes. Using γH2AX as a molecular marker for the DNA lesions, we identified that all of the broad-spectrum histone deacetylase inhibitors tested augment doxorubicin-induced DNA damage. Furthermore, it is evident from the fluorescence photomicrographs of stained nuclei that the histone deacetylase inhibitors also augment doxorubicin-induced hypertrophy. These observations highlight the importance of investigating potential side-effects, in relevant model systems, which may be associated with emerging combination therapies for cancer.

The unreimbursed costs of preventing revision surgery in adult spinal deformity: analysis of cost-effectiveness of proximal junctional failure prevention with ligament augmentation.

PubMed

Safaee, Michael M; Dalle Ore, Cecilia L; Zygourakis, Corinna C; Deviren, Vedat; Ames, Christopher P

2018-05-01

OBJECTIVE Proximal junctional kyphosis (PJK) is a well-recognized complication of surgery for adult spinal deformity and is characterized by increased kyphosis at the upper instrumented vertebra (UIV). PJK prevention strategies have the potential to decrease morbidity and cost by reducing rates of proximal junctional failure (PJF), which the authors define as radiographic PJK plus clinical sequelae requiring revision surgery. METHODS The authors performed an analysis of 195 consecutive patients with adult spinal deformity. Age, sex, levels fused, upper instrumented vertebra (UIV), use of 3-column osteotomy, pelvic fixation, and mean time to follow-up were collected. The authors also reviewed operative reports to assess for the use of surgical adjuncts targeted toward PJK prevention, including ligament augmentation, hook fixation, and vertebroplasty. The cost of surgery, including direct and total costs, was also assessed at index surgery and revision surgery. Only revision surgery for PJF was included. RESULTS The mean age of the cohort was 64 years (range 25-84 years); 135 (69%) patients were female. The mean number of levels fused was 10 (range 2-18) with the UIV as follows: 2 cervical (1%), 73 upper thoracic (37%), 108 lower thoracic (55%), and 12 lumbar (6%). Ligament augmentation was used in 99 cases (51%), hook fixation in 60 cases (31%), and vertebroplasty in 71 cases (36%). PJF occurred in 18 cases (9%). Univariate analysis found that ligament augmentation and hook fixation were associated with decreased rates of PJF. However, in a multivariate model that also incorporated age, sex, and UIV, only ligament augmentation maintained a significant association with PJF reduction (OR 0.196, 95% CI 0.050-0.774; p = 0.020). Patients with ligament augmentation, compared with those without, had a higher cost of index surgery, but ligament augmentation was overall cost effective and produced significant cost savings. In sensitivity analyses in which we independently varied the reduction in PJF, cost of ligament augmentation, and cost of reoperation by ± 50%, ligament augmentation remained a cost-effective strategy for PJF prevention. CONCLUSIONS Prevention strategies for PJK/PJF are limited, and their cost-effectiveness has yet to be established. The authors present the results of 195 patients with adult spinal deformity and show that ligament augmentation is associated with significant reductions in PJF in both univariate and multivariate analyses, and that this intervention is cost-effective. Future studies will need to determine if these clinical results are reproducible, but for high-risk cases, these data suggest an important role of ligament augmentation for PJF prevention and cost savings.

Comparison of the hydrogeology and water quality of a ground-water augmented lake with two non-augmented lakes in northwest Hillsborough County, Florida

USGS Publications Warehouse

Metz, Patricia A.; Sacks, Laura A.

2002-01-01

The hydrologic effects associated with augmenting a lake with ground water from the Upper Floridan aquifer were examined in northwest Hillsborough County, Florida, from June 1996 through May 1999. The hydrogeology, ground-water flow patterns, water budgets, and water-quality characteristics were compared between a lake that has been augmented for more than 30 years (Round Lake) and two nearby nonaugmented lakes (Dosson Lake and Halfmoon Lake). Compared to the other study lakes, Round Lake is in a more leakage-dominated hydrogeologic setting. The intermediate confining unit is thin or highly breached, which increases the potential for vertical ground-water flow. Round Lake has the least amount of soft, organic lake-bottom sediments and the lake bottom has been dredged deeper and more extensively than the other study lakes, which could allow more leakage from the lake bottom. The area around Round Lake has experienced more sinkhole activity than the other study lakes. During this study, three sinkholes developed around the perimeter of the lake, which may have further disrupted the intermediate confining unit.Ground-water flow patterns around Round Lake were considerably different than the nonaugmented lakes. For most of the study, groundwater augmentation artificially raised the level of Round Lake to about 2 to 3 feet higher than the adjacent water table. As a result, lake water recharged the surficial aquifer around the entire lake perimeter, except during very wet periods when ground-water inflow occurred around part of the lake perimeter. The non-augmented lakes typically had areas of ground-water inflow and areas of lake leakage around their perimeter, and during wet periods, ground-water inflow occurred around the entire lake perimeter. Therefore, the area potentially contributing ground water to the non-augmented lakes is much larger than for augmented Round Lake. Vertical head loss within the surficial aquifer was greater at Round Lake than the other study lakes, which is additional evidence of the limited confinement at Round Lake. A comparison of the water quality and lake-bottom sediments at the three lakes indicate that Round Lake is strongly influenced by the addition of large quantities of calcium-bicarbonate enriched augmentation water. Round Lake had higher alkalinity, pH, calcium and dissolved oxygen concentrations, specific conductance, and water clarity than the two non-augmented lakes. Round Lake was generally saturated to supersaturated with respect to calcite, but was undersaturated when augmentation was low and after high rainfall periods. Calcium carbonate has accumulated in the lake sediments from calcite precipitation, from macrophytes such as Nitella sp., and from the deposition of carbonate-rich mollusk shells, such as Planerbella sp., both of which thrive in the high alkalinity lake water. Lake-bottom sediments and aquatic biota at Round Lake had some of the highest radium-226 activity levels measured in a Florida lake. The high radium-226 levels (27 disintegrations per minute per dry mass) can be atrributed to augmenting the lake with ground water from the Upper Floridan aquifer. Although the ground water has relatively low levels of radium-226 (5.8 disintegrations per minute per liter), the large volumes of ground water added to the lake for more than 30 years have caused radium-226 to accumulate in the sediments and lake biota.The Round Lake basin had higher calcium and bicarbonate concentrations in the surficial aquifer than at the non-augmented lakes, which indicates the lateral leakage of calcium-bicarbonate enriched lake water into the surficial aquifer. Deuterium and oxygen-18 data indicated that water in well nests near the lake consists of as much as 100 percent lake leakage, and water from the augmentation well had a high percentage of recirculated lake water (between 59 and 73 percent lake leakage). The ground water surrounding Round Lake was undersaturated with respect to calcite, indicating that the water is capable of dissolving calcite in the underlying limestone aquifer. Annual and monthly ground-water outflow (lake leakage) was significantly higher at Round Lake than at the non-augmented lakes for the 3-year study period. Minimum estimates of the total annual ground-water inflow and outflow were made from monthly net ground-water flow values. Based on these estimates, total annual groundwater outflow from Round Lake was more than 10 times higher than for the non-augmented lakes. Local ground-water pumping, augmentation, and hydrogeologic factors are responsible for the high net ground-water outflow at Round Lake. Localized ground-water pumping causes the head difference between the lake and the Upper Floridan aquifer to increase, which increases lake leakage and results in lower lake levels. Augmenting the lake further increases the head difference between the lake, the water table, and the Upper Floridan aquifer, which results in an increase in lateral and vertical lake leakage. The lack of confinement or breaches in the intermediate confining unit facilitates the downward movement of this augmented lake water back into the Upper Floridan aquifer. The increase in ground-water circulation in the leakage-dominated hydrogeologic setting at Round Lake has made the basin more susceptible to karst activity (limestone dissolution, subsidence, and sinkhole formation)

An Examination of the Potential for Blissymbolics to Serve as the Foundation for a Tactile Symbol System

ERIC Educational Resources Information Center

Isaacson, Mickey

2012-01-01

The primary purpose of this study was to determine whether Blissymbolics have the potential for being developed into a tactile symbol communication system. Tactile techniques are used by many individuals with augmentative and alternative communication (AAC) needs. Tactile processing is optimized by the use of minimalistic stimuli, i.e., stimuli…

Enhanced Development of Auditory Change Detection in Musically Trained School-Aged Children: A Longitudinal Event-Related Potential Study

ERIC Educational Resources Information Center

Putkinen, Vesa; Tervaniemi, Mari; Saarikivi, Katri; Ojala, Pauliina; Huotilainen, Minna

2014-01-01

Adult musicians show superior auditory discrimination skills when compared to non-musicians. The enhanced auditory skills of musicians are reflected in the augmented amplitudes of their auditory event-related potential (ERP) responses. In the current study, we investigated longitudinally the development of auditory discrimination skills in…

ELECTRICAL PHENOMENA IN NERVE

PubMed Central

Shanes, Abraham M.

1949-01-01

The action of a number of agents, which may be classified as "stabilizers" and "unstabilizers" on the electrical oscillations and after-potentials in the squid giant axon has been examined. The effects on the spike, "positive overshoot," and "potassium potential" were also observed, but where possible concentrations were employed which left these phenomena unaltered. Veratrine augmented the oscillations and the negative after-potential, particularly with repetitive stimulation. Yohimbine caused a small long lasting positive after-potential and depressed the oscillations, effects also enhanced with repetitive activity. Cocaine and procaine suppressed the oscillations and the negative after-potential but DDT was completely inert. An elevation in the medium calcium depressed the oscillations and the naturally occurring negative after-potential; negative after-potentials induced with veratrine were increased by calcium. A decrease in the potassium augmented the oscillations and the negative after-potential. A hypothesis is presented in which these effects are interpreted in terms of potassium concentration at the fiber surface as regulated by a labile permeability and metabolism. This is discussed in relation to the available evidence for these factors. It is a pleasure to acknowledge the author's indebtedness to Dr. D. E. S. Brown, Director, and to his staff at the Bermuda Biological Station for Research for the cooperation and special facilities provided during the initiation of this work. Dr. T. Baylor of Princeton University very kindly provided the camera and film used in Bermuda. PMID:18139008

Diffusion and Electric Mobility of Ions within Isolated Cuticles of Citrus aurantium 1

PubMed Central

Tyree, Melvin T.; Wescott, Charles R.; Tabor, Christopher A.

1991-01-01

We report a new method for measuring cation and anion permeability across cuticles of sour orange, Citrus aurantium, leaves. The method requires the measurement of two electrical parameters: the diffusion potential arising when the two sides of the cuticle are bathed in unequal concentrations of a Cl− salt; and the electrical conductance of the cuticle measured at a salt concentration equal to the average of that used in the diffusion-potential measurement. The permeabilities of H+, Li+, Na+, K+, and Cs+ ranged from 2 × 10−8 to 0.6 × 10−8 meters per second when cuticles were bathed in 2 moles per cubic meter Cl− salts. The permeability of Cl− was 3 × 10−9 meters per second. The permeability of Li+, Na+, and K+ was about five times less when measured in 500 moles per cubic meter Cl− salts. We also report an asymmetry in cuticle-conductance values depending on the magnitude and the direction of current flow. The asymmetry disappears at low current-pulse magnitude and increases linearly with the magnitude of the current pulse. This phenomenon is explained in terms of transport-number effects in a bilayer model of the cuticle. Conductance is not augmented by current carried by exchangeable cations in cuticles; conductance is rate limited by the outer waxy layer of the cuticle. PMID:16668382

Structural, electronic, elastic, and thermal properties of CaNiH3 perovskite obtained from first-principles calculations

NASA Astrophysics Data System (ADS)

Benlamari, S.; Bendjeddou, H.; Boulechfar, R.; Amara Korba, S.; Meradji, H.; Ahmed, R.; Ghemid, S.; Khenata, R.; Omran, S. Bin

2018-03-01

A theoretical study of the structural, elastic, electronic, mechanical, and thermal properties of the perovskite-type hydride CaNiH3 is presented. This study is carried out via first-principles full potential (FP) linearized augmented plane wave plus local orbital (LAPW+lo) method designed within the density functional theory (DFT). To treat the exchange–correlation energy/potential for the total energy calculations, the local density approximation (LDA) of Perdew–Wang (PW) and the generalized gradient approximation (GGA) of Perdew–Burke–Ernzerhof (PBE) are used. The three independent elastic constants (C 11, C 12, and C 44) are calculated from the direct computation of the stresses generated by small strains. Besides, we report the variation of the elastic constants as a function of pressure as well. From the calculated elastic constants, the mechanical character of CaNiH3 is predicted. Pertaining to the thermal properties, the Debye temperature is estimated from the average sound velocity. To further comprehend this compound, the quasi-harmonic Debye model is used to analyze the thermal properties. From the calculations, we find that the obtained results of the lattice constant (a 0), bulk modulus (B 0), and its pressure derivative ({B}0^{\\prime }) are in good agreement with the available theoretical as well as experimental results. Similarly, the obtained electronic band structure demonstrates the metallic character of this perovskite-type hydride.

Optical properties of armchair (7, 7) single walled carbon nanotubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gharbavi, K.; Badehian, H., E-mail: hojatbadehian@gmail.com

2015-07-15

Full potential linearized augmented plane waves method with the generalized gradient approximation for the exchange-correlation potential was applied to calculate the optical properties of (7, 7) single walled carbon nanotubes. The both x and z directions of the incident photons were applied to estimate optical gaps, dielectric function, electron energy loss spectroscopies, optical conductivity, optical extinction, optical refractive index and optical absorption coefficient. The results predict that dielectric function, ε (ω), is anisotropic since it has higher peaks along z-direction than x-direction. The static optical refractive constant were calculated about 1.4 (z-direction) and 1.1 (x- direction). Moreover, the electron energymore » loss spectroscopy showed a sharp π electron plasmon peaks at about 6 eV and 5 eV for z and x-directions respectively. The calculated reflection spectra show that directions perpendicular to the tube axis have further optical reflection. Moreover, z-direction indicates higher peaks at absorption spectra in low range energies. Totally, increasing the diameter of armchair carbon nanotubes cause the optical band gap, static optical refractive constant and optical reflectivity to decrease. On the other hand, increasing the diameter cause the optical absorption and the optical conductivity to increase. Moreover, the sharp peaks being illustrated at optical spectrum are related to the 1D structure of CNTs which confirm the accuracy of the calculations.« less

Stability and Control CFD Investigations of a Generic 53 Degree Swept UCAV Configuration

NASA Technical Reports Server (NTRS)

Frink, Neal T.

2014-01-01

NATO STO Task Group AVT-201 on "Extended Assessment of Reliable Stability & Control Prediction Methods for NATO Air Vehicles" is studying various computational approaches to predict stability and control parameters for aircraft undergoing non-linear flight conditions. This paper contributes an assessment through correlations with wind tunnel data for the state of aerodynamic predictive capability of time-accurate RANS methodology on the group's focus configuration, a 53deg swept and twisted lambda wing UCAV, undergoing a variety of roll, pitch, and yaw motions. The vehicle aerodynamics is dominated by the complex non-linear physics of round leading-edge vortex flow separation. Correlations with experimental data are made for static longitudinal/lateral sweeps, and at varying frequencies of prescribed roll/pitch/yaw sinusoidal motion for the vehicle operating with and without control surfaces. The data and the derived understanding should prove useful to the AVT-201 team and other researchers who are developing techniques for augmenting flight simulation models from low-speed CFD predictions of aircraft traversing non-linear regions of a flight envelope.

A linear quadratic Gaussian with loop transfer recovery proximity operations autopilot for spacecraft. M.S. Thesis - MIT

NASA Technical Reports Server (NTRS)

Chen, George T.

1987-01-01

An automatic control scheme for spacecraft proximity operations is presented. The controller is capable of holding the vehicle at a prescribed location relative to a target, or maneuvering it to a different relative position using straight line-of-sight translations. The autopilot uses a feedforward loop to initiate and terminate maneuvers, and for operations at nonequilibrium set-points. A multivariate feedback loop facilitates precise position and velocity control in the presence of sensor noise. The feedback loop is formulated using the Linear Quadratic Gaussian (LQG) with Loop Transfer Recovery (LTR) design procedure. Linear models of spacecraft dynamics, adapted from Clohessey-Wiltshire Equations, are augmented and loop shaping techniques are applied to design a target feedback loop. The loop transfer recovery procedure is used to recover the frequency domain properties of the target feedback loop. The resulting compensator is integrated into an autopilot which is tested in a high fidelity Space Shuttle Simulator. The autopilot performance is evaluated for a variety of proximity operations tasks envisioned for future Shuttle flights.

Chemosensitization as a Means to Augment Commercial Antifungal Agents

PubMed Central

Campbell, Bruce C.; Chan, Kathleen L.; Kim, Jong H.

2012-01-01

Antimycotic chemosensitization and its mode of action are of growing interest. Currently, use of antifungal agents in agriculture and medicine has a number of obstacles. Foremost of these is development of resistance or cross-resistance to one or more antifungal agents. The generally high expense and negative impact, or side effects, associated with antifungal agents are two further issues of concern. Collectively, these problems are exacerbated by efforts to control resistant strains, which can evolve into a treadmill of higher dosages for longer periods. This cycle in turn, inflates cost of treatment, dramatically. A further problem is stagnation in development of new and effective antifungal agents, especially for treatment of human mycoses. Efforts to overcome some of these issues have involved using combinations of available antimycotics (e.g., combination therapy for invasive mycoses). However, this approach has had inconsistent success and is often associated with a marked increase in negative side effects. Chemosensitization by natural compounds to increase effectiveness of commercial antimycotics is a somewhat new approach to dealing with the aforementioned problems. The potential for safe natural products to improve antifungal activity has been observed for over three decades. Chemosensitizing agents possess antifungal activity, but at insufficient levels to serve as antimycotics, alone. Their main function is to disrupt fungal stress response, destabilize the structural integrity of cellular and vacuolar membranes or stimulate production of reactive oxygen species, augmenting oxidative stress and apoptosis. Use of safe chemosensitizing agents has potential benefit to both agriculture and medicine. When co-applied with a commercial antifungal agent, an additive or synergistic interaction may occur, augmenting antifungal efficacy. This augmentation, in turn, lowers effective dosages, costs, negative side effects and, in some cases, countermands resistance. PMID:22393330

Aromatase inhibitors augment nociceptive behaviors in rats and enhance the excitability of sensory neurons

PubMed Central

Robarge, Jason D.; Duarte, Djane B.; Shariati, Behzad; Wang, Ruizhong; Flockhart, David A.; Vasko, Michael R.

2016-01-01

Although aromatase inhibitors (AIs) are commonly used therapies for breast cancer, their use is limited because they produce arthralgia in a large number of patients. To determine whether AIs produce hypersensitivity in animal models of pain, we examined the effects of the AI, letrozole, on mechanical, thermal, and chemical sensitivity in rats. In ovariectomized (OVX) rats, administering a single dose of 1 or 5 mg/kg letrozole significantly reduced mechanical paw withdrawal thresholds, without altering thermal sensitivity. Repeated injection of 5 mg/kg letrozole in male rats produced mechanical, but not thermal, hypersensitivity that extinguished when drug dosing was stopped. A single dose of 5 mg/kg letrozole or daily dosing of letrozole or exemestane in male rats also augmented flinching behavior induced by intraplantar injection of 1000 nmol of adenosine 5′-triphosphate (ATP). To determine whether sensitization of sensory neurons contributed to AI-induced hypersensitivity, we evaluated the excitability of neurons isolated from dorsal root ganglia of male rats chronically treated with letrozole. Both small and medium-diameter sensory neurons isolated from letrozole-treated rats were more excitable, as reflected by increased action potential firing in response to a ramp of depolarizing current, a lower resting membrane potential, and a lower rheobase. However, systemic letrozole treatment did not augment the stimulus-evoked release of the neuropeptide calcitonin gene-related peptide (CGRP) from spinal cord slices, suggesting that the enhanced nociceptive responses were not secondary to an increase in peptide release from sensory endings in the spinal cord. These results provide the first evidence that AIs modulate the excitability of sensory neurons, which may be a primary mechanism for the effect of these drugs to augment pain behaviors in rats. PMID:27072527

Hepatic oxidative stress in ovariectomized transgenic mice expressing the hepatitis C virus polyprotein is augmented through suppression of adenosine monophosphate-activated protein kinase/proliferator-activated receptor gamma co-activator 1 alpha signaling.

PubMed

Tomiyama, Yasuyuki; Nishina, Sohji; Hara, Yuichi; Kawase, Tomoya; Hino, Keisuke

2014-10-01

Oxidative stress plays an important role in hepatocarcinogenesis of hepatitis C virus (HCV)-related chronic liver diseases. Despite the evidence of an increased proportion of females among elderly patients with HCV-related hepatocellular carcinoma (HCC), it remains unknown whether HCV augments hepatic oxidative stress in postmenopausal women. The aim of this study was to determine whether oxidative stress was augmented in ovariectomized (OVX) transgenic mice expressing the HCV polyprotein and to investigate its underlying mechanisms. OVX and sham-operated female transgenic mice expressing the HCV polyprotein and non-transgenic littermates were assessed for the production of reactive oxygen species (ROS), expression of inflammatory cytokines and antioxidant potential in the liver. Compared with OVX non-transgenic mice, OVX transgenic mice showed marked hepatic steatosis and ROS production without increased induction of inflammatory cytokines, but there was no increase in ROS-detoxifying enzymes such as superoxide dismutase 2 and glutathione peroxidase 1. In accordance with these results, OVX transgenic mice showed less activation of peroxisome proliferator-activated receptor-γ co-activator-1α (PGC-1α), which is required for the induction of ROS-detoxifying enzymes, and no activation of adenosine monophosphate-activated protein kinase-α (AMPKα), which regulates the activity of PGC-1α. Our study demonstrated that hepatic oxidative stress was augmented in OVX transgenic mice expressing the HCV polyprotein by attenuation of antioxidant potential through inhibition of AMPK/PGC-1α signaling. These results may account in part for the mechanisms by which HCV-infected women are at high risk for HCC development when some period has passed after menopause. © 2013 The Japan Society of Hepatology.

A direct application of the non-linear inverse transformation flight control system design on a STOVL aircraft

NASA Technical Reports Server (NTRS)

Chung, W. W.; Mcneill, W. E.; Stortz, M. W.

1993-01-01

The nonlinear inverse transformation flight control system design method is applied to the Lockheed Ft. Worth Company's E-7D short takeoff and vertical land (STOVL) supersonic fighter/attack aircraft design with a modified General Electric F110 engine which has augmented propulsive lift capability. The system is fully augmented to provide flight path control and velocity control, and rate command attitude hold for angular axes during the transition and hover operations. In cruise mode, the flight control system is configured to provide direct thrust command, rate command attitude hold for pitch and roll axes, and sideslip command with turn coordination. A control selector based on the nonlinear inverse transformation method is designed specifically to be compatible with the propulsion system's physical configuration which has a two dimensional convergent-divergent aft nozzle, a vectorable ventral nozzle, and a thrust augmented ejector. The nonlinear inverse transformation is used to determine the propulsive forces and nozzle deflections, which in combination with the aerodynamic forces and moments (including propulsive induced contributions), and gravitational force, are required to achieve the longitudinal and vertical acceleration commands. The longitudinal control axes are fully decoupled within the propulsion system's performance envelope. A piloted motion-base flight simulation was conducted on the Vertical Motion Simulator (VMS) at NASA Ames Research Center to examine the handling qualities of this design. Based on results of the simulation, refinements to the control system have been made and will also be covered in the report.

Exogrip: assisted hand strength glove - biomed 2011.

PubMed

Best, Jade E; Bostick, Nehemiah F; Connelly, John R; Dunn, Michael G; Gelles, Richard A; Norvell, Elizabeth K; Waugaman, William B; Mims, Capt Willie H

2011-01-01

A large number of American troops fighting in Afghanistan and Iraq have received wounds in their upper extremities leading to significant nerve damage and loss of strength. These injuries impair their ability to perform day-to-day tasks such as lifting a cup of coffee or opening a door. Although the cause of some injuries in service-people is often unique to their employment, civilian employees in other industries are also plagued with similar physical damage due to other kinds of injuries. Our goal is to develop a device to augment the strength of injured troops and civilian workers so they can perform everyday tasks despite their physical limitations. The ExoGrip is a glove designed to provide this necessary strength augmentation. The ExoGrip consists primarily of pressure sensors, linear actuators, and a microcontroller to provide a force multiplier based on a person’s strength. The goal of the first phase of the project was to conduct research and also produce a working prototype of one finger. This goal was achieved by a group of classmates who started the project a year before. Their research and feasibility analysis ended in the mechanical movement of a single finger when the sensors were activated. The next phase of this project is to design and integrate a working prototype that manipulates all four fingers, while keeping the thumb in a fixed position. This paper describes the integration of new microcontrollers, linear actuators utilizing pulse width modulation technology, and improved pressure sensors needed to manipulate the fingers, as well as laying the foundation for future testing and development of a final product.